ARTICLE | doi:10.20944/preprints202102.0049.v1
Subject: Engineering, Automotive Engineering Keywords: Flowability; Powder rheometer; Powder characterization
Online: 1 February 2021 (15:08:09 CET)
The flowability of a powder is a characteristic dependent on both the particle ensemble's physical properties as well as the testing equipment and conditions. In powder bed additive manufacturing processes (SLM, EBM), flowability can be used to predict the quality of the deposited powder layer. However, how representative flowability is for the powder bed layer quality is not always clear.In this work, we compared several steel powders, as well as different testing methods. Each powder had an individual combination of composition or particle size distribution. Furthermore, the flowability testing equipment and methods were selected according to standards (Tap density, Hall flow) or referring to the published literature (angle of repose, FT4 Powder Rheometer). After measuring the flowability of different samples for each testing method, we created a database to evaluate a first correlation between the different testing methods. Finally, with a Powder Rheometer, we investigated for one sample some flow properties as function of different particle size distributions.
ARTICLE | doi:10.20944/preprints202102.0200.v1
Subject: Environmental And Earth Sciences, Atmospheric Science And Meteorology Keywords: Iron ore; Maghemite; Nonstoichiometric magnetite; X-Ray diffraction; Ore characterization
Online: 8 February 2021 (12:13:32 CET)
Maghemite (γ-Fe2O3) is a mineral formed from magnetite oxidation at low temperatures, an intermediate metastable term of the magnetite to hematite oxidation and could be mixed with both. It has magnetic susceptibility similar to magnetite, crystal structure close to magnetite with which it forms a solid solution, while compositionally it equals hematite. Maghemite is thus easily misidentified as magnetite by X-ray diffraction and/or as hematite by spot chemical analysis in iron ore characterization routines. Nonstoichiometric magnetite could be quantified in samples of Brazilian soils and iron ores by the Rietveld method using a constrained refinement of the X-ray patterns. The results were confirmed by reflected light microscopy and Raman spectroscopy, thus qualitatively validating the method. X-ray diffraction with the refinement of the isomorphic substitution of Fe2+ by Fe3+ along the magnetite-maghemite solid solution could help to suitably characterize maghemite in iron ores, allowing for the evaluation of its ultimate influence on mineral processing, by affecting its surface and breakage properties.
ARTICLE | doi:10.20944/preprints201811.0524.v1
Online: 21 November 2018 (11:27:40 CET)
The study sought to determine solar irradiation in Homa Bay County which can be tapped and utilized in improving lives of residents of the region by converting the solar thermal energy in Home Bay to other forms of energy such as electric form, mechanical form and light. The study was done by assessing the local atmospheric conditions which included sunshine duration data and air temperature records for the period of two years and the data obtained subjected to statistical analysis to determine the localized characteristics of the resource. The characteristics that were examined include; seasonal and annual power expectations as well as resource reliability. The solar irradiance of Home County was found to be 768.0 W/m2.
ARTICLE | doi:10.20944/preprints202304.0670.v1
Subject: Engineering, Electrical And Electronic Engineering Keywords: low-cost instrumentation; characterization setup; multidimensional characterization; metasurfaces; millimeter-wave
Online: 21 April 2023 (03:58:20 CEST)
3D printing is commonly used to create complex objects at a low cost. It has also been applied in the fabrication of metamaterials and metasurfaces, which alter the propagation path of electromagnetic waves. These structures have diverse applications, including enhancing beam direction, improving antenna gain and signal-to-noise ratio, and creating filters and reflectors. Metasurfaces are cheap to fabricate and their use is expected to boost antenna efficiency in 5G telecommunications and beyond. However, accurately characterizing their profile remains a significant challenge. This paper presents a low-cost fully automated 4-axis instrument for microwave metasurface charac-terization, overcoming limitations of manual methods and offering an efficient and accurate approach. This research represents a significant advancement in microwave metasurface characterization, enabling sophisticated techniques to advance wireless communication technolo-gies, as it is the case of the future 5G and millimeter-wave communication systems. The equipment has an approximate cost of $1550 USD and was able to characterize a metalens with a focal distance of 20 cm designed for signals at 30 GHz. It was possible to create 2D and 3D profiles of the intensity distribution focused by the metalens and extract parameters such as the gain (8.05 dB), 3dB depth of focus (11 cm) and full width at half maximum (2.17 cm). The comparison of the measurements with the diffraction calculations of the metalens showed a very good agreement between the in-tensity distributions and the parameters of the metalens.
ARTICLE | doi:10.20944/preprints201801.0163.v1
Subject: Chemistry And Materials Science, Polymers And Plastics Keywords: methacrylate monomers, cosmetics, polymerization rate, thermal properties characterization, mechanical properties characterization
Online: 17 January 2018 (14:05:09 CET)
Mixtures of methacrylic polymers are the most common materials for making composites to be used as resins for dental and cosmetic applications. Some of these mixtures are composed by poly (ethyl methacrylate) (PEMA) and poly (methyl methacrylate) (PMMA), which constitute a solid component to be mixed with a liquid component made out of methacrylate monomers. The reaction between the thermal initiator benzoyl peroxyde (BPO) present in the solid component and the activator of the polymerization process, N,N-dimethyl-p-toluidine (DMT) present in the liquid component, gives rise to thermoset materials. In the present study, different liquid formulations composed by a mixture of two methacrylic monomers, ethyl methacrylate (EMA) and triethylene glycol dimethacrylate (TEGDMA) for cosmetic applications, were prepared and characterized, using a commercial powder (POW) composed by PEMA and PMMA. With the aim of improving workability during final application of the material, it was necessary to slow down the polymerization rate of liquid formulations. Their thermal behaviour was investigated by DSC in order to check the polymerization rate. Thermal stability of final materials was determined by TGA. DMTA, microindentation hardness and impact tests were performed on final materials, to assess their performance with respect to standard formulation. The combination of thermal and mechanical properties allows choosing which formulations could be suitable for use in cosmetics.
ARTICLE | doi:10.20944/preprints202308.1363.v1
Subject: Biology And Life Sciences, Horticulture Keywords: plum; underutilized; characterization; composition
Online: 18 August 2023 (11:48:20 CEST)
Plums are widely distributed in Türkiye and around the world. Different wild grown plum spe-cies such as Prunus spinosa, Prunus cerasifera and Prunus domestica shows abundance of different climatic zones in Türkiye. Seed propagated diverse plum trees has been growing Anatolia for centuries and fruits of wild plants has economic value. In this study a total of 8 wild grown blackthorn (Prunus spinosa) sampled from Ispir district of Erzurum province and subjected to morphological, biochemical and antioxidant characterization. Taste, aroma, and juiciness were used as the criteria for sensory analysis, and a trained panel of five experts established and evaluated the sensory characteristics of the fruits of the blackthorn. Fruit weight, fruit skin and flesh color as L*, a* and b* values were the main morphological parameters. For biochemical analysis, organic acids, SSC (Soluble Solid Content), vitamin C, total anthocyanins, total phenol-ic content and total antioxidant capacity were determined. Antioxidant capacity was determined by FRAP (ferric reducing antioxidant power) assay. Results indicated significant differences among genotypes. Fruit weight were found between 2.78-3.67 g. Skin L∗, a∗ and b∗ values were 13.11-16.12, 2.56-3.85 and 2.01-3.44, respectively. Flesh L∗, a∗ and b∗ values were in range of 17.45-20.37, 4.88-6.73 and 4.12-5.66, respectively. SSC content was ranged from 18.66% to 21.07%. The total phenolic content (TPC), total anthocyanin content (TAC) and ferric reducing antioxi-dant power (FRAP) were between 372-504 mg GAE/100 g; 53-72 mg cy-3-g eq./100 g and 107-134 mmol Fe (II) eq./g, respectively. The dominant organic acid was malic acid for all genotypes and varied from 1.04 g/100 g to 1.52 g/100 g fresh weight base. Results indicated the importance wild blackthorn fruits for human health.
ARTICLE | doi:10.20944/preprints202112.0049.v1
Subject: Biology And Life Sciences, Agricultural Science And Agronomy Keywords: bacterial wilt; biological control; phage; microscopy; sequencing; molecular characterization; genomic characterization; depolymerase
Online: 3 December 2021 (10:36:47 CET)
Ralstonia solanacearum is the causative agent of bacterial wilt, one of the most destructive plant diseases. While chemical control has an environmental impact, biological control strategies can allow sustainable agrosystems. Three lytic bacteriophages (phages) of R. solanacearum with biocontrol capacity in environmental water and plant were isolated from river water in Europe but not fully characterized, their genomic characterization being fundamental to understand their biology. In this work, the phage genomes were sequenced and subjected to bioinformatic analysis. The morphology was also observed by electron microscopy. Phylogenetic analyses were performed with a selection of phages able to infect R. solanacearum and the closely related phytopathogenic species R. pseudosolanacearum. The results indicated that the genomes of vRsoP-WF2, vRsoP-WM2 and vRsoP-WR2 range from 40,688 to 41,158 bp with almost 59% GC-contents, 52 ORFs in vRsoP-WF2 and vRsoP-WM2, and 53 in vRsoP-WR2 but, with only 22 or 23 predicted proteins with functional homologs in databases. Among them, two lysins and one exopolysaccharide (EPS) depolymerase, this type of depolymerase being identified in R. solanacearum phages for the first time. These three European phages belong to the same novel species within the Gyeongsanvirus, Autographiviridae family (formerly Podoviridae). These genomic data will contribute to a better understanding of the abilities of these phages to damage host cells and, consequently, to an improvement in the biological control of R. solanacearum.
REVIEW | doi:10.20944/preprints202309.1862.v1
Subject: Chemistry And Materials Science, Materials Science And Technology Keywords: antimicrobial coatings; functionalization; characterization methodology
Online: 27 September 2023 (14:35:53 CEST)
This comprehensive review addresses topics relevant to understanding of characterization of antimicrobial coatings used in surface modifications of yarns and materials intended for usage in medical and dental applications. These coatings are created using various physical and chemical methods to achieve efficient, homogeneous, and uniform layers on different surfaces and materials, with the goal of imparting antimicrobial and/or antiviral properties. Antimicrobial coatings must contain active compounds effective against various microorganisms, including those resistant to antibiotics. Examples of such compounds include metallic nanoparticles (such as silver, copper, and gold) and nanoparticles of metal oxides (such as zinc, titanium, and aluminum). Once materials intended for medical applications are coated, they undergo extensive testing and characterization, for which the methodologies will be presented in this chapter. Despite their wide efficiency in medical applications, concerns are raised regarding the potential toxicity of nanoparticles to living organisms. Therefore, the development of novel legal frameworks is anticipated, which will depend on proper characterization and testing procedures. This paper provides a summary of the current state-of-the-art methodologies for characterizing nanoparticles in antimicrobial coatings on materials with different roughness and structures and specifies the problems related with accumulation of antimicrobial nanoparticles in a human body.
ARTICLE | doi:10.20944/preprints202305.1250.v1
Subject: Chemistry And Materials Science, Ceramics And Composites Keywords: Nd-YAG; Laser; Optical characterization
Online: 17 May 2023 (12:56:53 CEST)
Materials known as Nd:YAG are crystalline materials of the cubic system made from neodymium-doped yttrium aluminum garnet, which among others, have excellent optical properties. Nd:YAG four-level laser devices are highly used in both the health and industrial sectors. In this study, a simple and inexpensive alternative to manufacturing Nd:YAG materials through solid state reactions following powder processing routes was proposed. For this, an intense mixture of the precursor materials (Al2O3 and Y2O3) was carried out, followed by the addition of neodymium atoms to improve the optical properties of the resulting material. High energy mechanical mixing of the precursor powders resulted in submicron particles, with good size distributions of the powders. The advance of YAG formation was monitored by intermediate phase formation during heat treatment through interrupted tests at different temperatures and analysis by X-ray diffraction. From this analysis, it was found that reaction for the formation of the desired YAG is completed at 1500°C. Fourier-transform infrared spectroscopy analyses determined the presence of functional groups corresponding to the YAG. Finally, the study by optical emission spectroscopy showed wavelengths in agreement with the electronic structure of the elements of the synthesized Nd:YAG.
ARTICLE | doi:10.20944/preprints202311.0240.v1
Subject: Chemistry And Materials Science, Materials Science And Technology Keywords: PBAT; Lignin; Biodegradable; film; fabrication; characterization
Online: 6 November 2023 (01:20:36 CET)
Biodegradable and renewable plastic films have been regarded as promising alternative green materials to achieve the substitution polythene (PE)films to reduce plastic pollution. Poly (butylene adipate-co-terephthalate) (PBAT) is a kind of biodegradable polyester, which is widely used in the production of biodegradable mulching films. However, the high cost of PBAT limited it applications. Thus, lignin, one of the most abundant biomass resources was incorporated into PBAT matrix in the present work. A series of Lignin/PBAT biodegradable plastics films with different Lignin/PBAT weight ratios (0.00 %-5.00 %) were successfully fabricated using twin screw and twin roll extruders. The chemical compositions, morphologies, thermal stabilities, mechanical properties, and barrier properties of samples were characterized by XRD, FTIR, TG/DSC, mechanical testing machine, and WVTR, respectively. Results show that the corporation of lignin into PBAT matrix could lead to improved thermal stabilities, mechanical properties and barrier properties of films even after Xenon lamp aging process, especially when Lignin/PBAT weight ratio is 1.00 % in the present work. This work provides a very promising approach for fabrication of biodegradable plastics films with low cost, enhanced mechanical properties and barrier properties, the as-prepared samples may have potential applications in agricultural or food packaging materials.
REVIEW | doi:10.20944/preprints202310.1024.v1
Subject: Biology And Life Sciences, Food Science And Technology Keywords: Characterization; Arazá; phenolic compounds; systematic review
Online: 17 October 2023 (05:43:06 CEST)
(1) Background: In Eugenia Stipitata Mac Vaugh (Arazá), there is an abundance of flavonoids, carotenoids, and phenolic acids, which are bioactive compounds with antioxidant, anticarcinogenic, antimicrobial, anti-inflammatory, antispasmodic, antiulcer, and cardiovascular disease prevention benefits. Therefore, the aim of this review is to compile the compounds that have been identified in the fruit and gather information about secondary metabolites to establish their potential preventive and therapeutic effects; (2) Methods: a literature search was conducted in repositories and databases such as Science Direct, Scopus, PubMed, Web of Science, Agriculture Collection Gale, SAGE, OXFORD University, DOAJ, among others. Articles identifying and quantifying bioactive compounds present in Arazá were included; (3) Results: Five studies meeting the inclusion criteria were incorporated, resulting in the compilation of 82 compounds, of which 24 were identified and quantified, while 58 were solely identified. This review was able to identify and report the concentration, and in some cases, the quantity, of phenolic compounds with antioxidant and anti-inflammatory capabilities present in Arazá; (4) Conclusions: With this scope, it was possible to obtain a more comprehensive understanding of the fruit's potential to potentially enhance health aspects, thereby providing greater prominence and added value to this product, allowing for more frequent inclusion in the diets of consumers, and even enabling exportation.
ARTICLE | doi:10.20944/preprints202307.1550.v1
Subject: Chemistry And Materials Science, Polymers And Plastics Keywords: PANI; polymerization; particle size; dispersion; characterization
Online: 22 July 2023 (17:08:55 CEST)
Polyaniline or PANI is a conductive polymer (CPs) with flexibility in turning into conducting properties. The drawback is mainly in terms of limited mechanical properties improvement which attracted the interest in fabrication of PANI with other polymeric materials. PANI-PVL composites film was synthesized and fabricated in this work with chronological steps according to the objectives aligned in two different phases. The first phase determines the optimum parameters to synthesize nanosized PANI. The ideal initial molar ratio, r was 1, stirring speed of 600 rpm, purified by filtration, synthesis temperature of 25 oC, washed by dopant acid, acetone and distilled water. The usage of non-ionic surfactant, Triton X-100 (TX100) with 0.1 % concentration favours the formation of smaller particle size of PANI and good dispersibility compared to the usage of anionic sodium dodecyl sulphate (SDS). The synthesis of PANI in nanosized dimension has the potential to be applied for antimicrobial applications such as gloves and antimicrobial coating of frequent contact points in the near future.
ARTICLE | doi:10.20944/preprints202304.1262.v1
Subject: Environmental And Earth Sciences, Sustainable Science And Technology Keywords: Technically Hydrolyzed Lignin; Carbonization; Biochar Characterization
Online: 30 April 2023 (04:48:39 CEST)
The present study aimed at utilizing technically hydrolyzed lignin (THL), industrial biomass residue, derived in high-temperature diluted sulphuric acid hydrolysis of softwood and hardwood chips to sugars. The THL was carbonized in horizontal tube furnace at atmospheric pressure, in inert atmosphere and at three different temperatures (500, 600 and 700 ºC). Biochar chemical composition was investigated along with its HHV, thermal stability (thermogravimetric analysis) and textural properties. Surface area and pore volume were measured with nitrogen physisorption analysis often named upon Brunauer–Emmett–Teller (BET). Increasing the carbonization temperature reduced volatile organic compounds (40 ÷ 96 wt. %), increased fixed carbon (2.11 to 3.68 times the wt. % of fixed carbon in THL), ash and C-content. Moreover, H and O were reduced, while N- and S-content were below the detection limit. This suggested biochar application as solid biofuel. The biochar Fourier-transform infrared (FTIR) spectra revealed that the functional groups were gradually lost thus, forming materials having merely polycyclic aromatic structures and high condensation rate. The biochar obtained at 600 and 700 ºC proved having properties typical for microporous adsorbents, suitable for selective adsorption purposes. Based on the latest observations another biochar application was proposed - as catalyst.
ARTICLE | doi:10.20944/preprints202111.0131.v1
Subject: Medicine And Pharmacology, Pharmacology And Toxicology Keywords: Rosuvastatine; polymorphism; preformulation; tablet; physicochemical characterization
Online: 8 November 2021 (12:07:56 CET)
This work proposes a methodology for the design, development, optimisation, and evaluation of amorphous rosuvastatin calcium tablets (BCS class II drug). The main goal was to ensure rapid disintegration and high dissolution rate of the active ingredient, thus enhancing its bioavailability. The design started from a careful selection of excipients, which due to their characteristics and proportions within the formulation allowed the use of their properties such as fluidity or granulometric distribution. The formulation was characterised using scanning electron microscopy (SEM), differential scanning calorimetry (DSC), thermogravimetry (TGA), Fourier transform infrared spectroscopy (FT-IR) and powder X-ray diffraction (PXRD) methods. The galenic SeDeM methodology was used to establish the profile of the active ingredient-excipient mixture and guarantee its suitability for producing tablets by the direct compression method. The results demonstrate that the amorphous rosuvastatin calcium tablets formulation developed made it possible to obtain cost-effective tablets by direct compression with optimal pharmacotechnical characteristics that showed a remarkable disintegration and dissolution rate. The manufactured tablets complied with the pharmacopoeia guidelines regarding uniformity of weight, tablet hardness, thickness, friability, in vitro disintegration time and dissolution profile.
ARTICLE | doi:10.20944/preprints201808.0005.v1
Subject: Chemistry And Materials Science, Chemical Engineering Keywords: polymer; characterization; sludge conditioning; UV; flocculant
Online: 1 August 2018 (08:18:34 CEST)
Controlling the concentration of free radicals in polymerization systems is advantageous for preparing cationic polyacrylamide (CPAM) with high molecular weight and acceptable dissolvability. In this study, a novel ultraviolet (UV)-initiated system characterized with adjustable light intensity and redox-azo complex initiator was used to synthesize a CPAM flocculant named NP. Comparatively, another CPAM flocculant named SP with stable UV light intensity and single initiator was prepared. The chemical structure, morphology, and thermal stability were analyzed through instrumental analysis. Proton nuclear magnetic resonance indicated that NP was successfully prepared, and a small fraction of cationic homopolymer was mixed in the product. Polymerization conditions were optimized, and polymerization mechanism was determined by investigating the effects of various parameters on intrinsic viscosity, conversion, and dissolvability. Results showed that the best performance was obtained at indexes of 0.45 wt‰ redox initiator concentration, 0.2 wt‰ azo initiator concentration, 40.0 wt% of cationic monomer, first- and second-stage light intensities of 8.5 and 13 mW/cm2, respectively, and 3 wt% urea. Sludge conditioning performances of NP and SP were comparatively evaluated, and the mechanism was determined by investigating the sedimentation behavior and floc size distribution. High intrinsic viscosity, porous morphology structure, and the mixed cationic homopolymer of NP resulted in better sludge conditioning performance.
ARTICLE | doi:10.20944/preprints201703.0226.v1
Subject: Chemistry And Materials Science, Biomaterials Keywords: hydroxyapatite; xenografts; physicochemical-characterization; tissue reaction
Online: 31 March 2017 (08:35:07 CEST)
Detailed information about graft material characteristic is crucial to evaluate their clinical outcomes. The present study evaluates the physicochemical characteristics of two xenografts manufactured on an industrial scale deproteinized at different temperatures (non-sintered and sintered) in accordance with a protocol previously used in sinus lift procedures. It compares how the physico-chemical properties influence the material performance in vivo with a histomorphometric study in retrieved bone biopsies following maxillary sinus augmentation, in 10 clinical cases. X-ray diffraction analysis revealed typical structure of hydroxyapatite for both materials. Both xenografts are porous and exhibit intraparticle pores. Strong differences were observed in terms of porosity, cristallinity, and calcium/phosphate. Histomorphometric measurements on the bone biopsies showed statistically significant differences. The physicochemical assessment of both xenografts in accordance with the protocol developed at industrial scale confirmed that these products present excelent biocompatibilitity, with characteristics similar to natural bone. The sintered HAs xenograft exhibit higher osteoconductivity although were not complete resorbable (30.80±0.88% residual material). On the other hand, the non-sintered HAs xerograft induced about 25.92±1.61% of new bone and almost complete degradation after 6 months implantation. Differences in physico-chemical characteristics found between the two HAs xenograft determine different behavior of this material.
ARTICLE | doi:10.20944/preprints202310.1338.v1
Subject: Chemistry And Materials Science, Materials Science And Technology Keywords: butadiene; expanded perlite; modification; composite; structural characterization
Online: 20 October 2023 (11:50:50 CEST)
The article presents a method for obtaining new composites using a well-known mineral, expanded perlite (EP), and an industrial polymer, butadiene rubber (BR). For the design of composites, a joint oxidative chlorophosphorylation reaction of BR and EP (as well as BR and modified EP) was carried out, and the modifications obtained from this reaction were further hydrolyzed. The structure and morphology of the obtained samples were characterized in detail using Fourier transform infrared spectroscopy, ultraviolet-visible spectroscopy, X-ray powder diffraction, as well as scanning electron microscopy, and energy-dispersive X-ray analysis. EP and BR were separately modified with a similar reaction and characterized for data interpretation.
ARTICLE | doi:10.20944/preprints202310.0253.v1
Subject: Biology And Life Sciences, Biology And Biotechnology Keywords: Bacillus; 16S rRNA; molecular characterization; rhizosphere; biocontroller
Online: 5 October 2023 (07:54:35 CEST)
Abrstract: Bacillus spp. it is a genus that is used to biocontrol post-harvest diseases in various vegetables and fruits during transportation and storage. It suppresses the development of pathogens such as gray mold (Botrytis cinerea) in strawberry cultivation. In this work, the molecular characterization of Bacillus spp. species was carried out. in three cities in Peru: Huaura, Chanchamayo and Cañete. The samples were collected from rhizospheric soil from crop areas, subsequently processed for microbiological isolation, molecular analysis using the 16S rRNA gene and bioinformatic analysis. In total, 14 strains were obtained where they were identified with a minimum of 92.05% and a maximum of 100% similarity: 8 strains of Bacillus subtilis, 4 strains of Bacillus licheniformis, 1 strain of Bacillus paralicheniformis and 1 strain of Bacillus cereus, all the strains were related by constructing a phylogenetic tree.
ARTICLE | doi:10.20944/preprints202308.0902.v1
Subject: Biology And Life Sciences, Ecology, Evolution, Behavior And Systematics Keywords: ecosystems; conservation; vegetation; phytocoenoses; association; ecological characterization
Online: 11 August 2023 (07:58:00 CEST)
The purpose of this paper is to develop a phytosociological, ecological, cytogenetic, eco-protective and economic study of the vegetation of the wetland ecosystems in the Vlădeasa Massif built by the phytocoenoses of the association Carici echinatae-Sphagnetum (Balázs 1942) Soó 1955. In order to attain the aim and objectives put forward we carried out 10 phytocoenological surveys (surveys) in the phytocoenoses of the ecosystems during the optimal vegetation periods related to the summer-serotinal season in the timeframe 2020-2021. The taxonomically inventoried species were included in an association table by the criteria of their belonging to the basic coenotaxa of the association, alliance, order, vegetation class. The outcomes of the phytocoenosis research of the vegetation of the wetland ecosystems were processed, analysed, interpreted based on tables, histograms, diagrams, regarding the numerical and percentage weight of the species in the ecological categories of bioforms, phytogeographic elements (geoelements) and cytogenetic elements. The ecological behaviour of the species confined in ecosystems was also analysed by their relationship with ecological factors, edaphic soil moisture, air temperature and chemical reaction of the soil. The current state of ecosystems, potential threats, sustainable conservation of biodiversity, dynamics of phytocenoses, economic and scientific relevance were also subjected to research. The results obtained in the surveyed territory were analysed and compared numerically and as percentage with the data provided by two reference scientific works belonging to authors who independently carried out research with a similar topic in two different geographical regions of the Western Carpathians.
ARTICLE | doi:10.20944/preprints202307.1348.v1
Subject: Engineering, Mining And Mineral Processing Keywords: Geometallurgy; comminution; ore characterization; variability; breakage test
Online: 20 July 2023 (08:34:45 CEST)
Comminution is the most power-demanding stage, and the lack of geometallurgical testing, often for financial reasons, may result in an inefficient operation. The Geopyörä Rock Breakage test was developed with the objective of making mineral variability data more accessible by providing both standard comminution parameters and rock mechanical properties at low cost, and with a modest sample size, allowing a larger number of samples to be tested to reduce uncertainties and assure productivity. The objective of this work is to present the results of an extensive validation of this new rock breakage method against two of the main tests currently in use, namely the SMC® and Bond ball mill work index tests. More than 100 samples have been tested and the results compared, showing that the new method can accurately estimate the parameters of the traditional tests. This confirms that the new test is a reliable tool for comminution and geometallurgical tests.
ARTICLE | doi:10.20944/preprints202305.1494.v1
Subject: Chemistry And Materials Science, Analytical Chemistry Keywords: Gold nanoparticles; Synthesis; Nanomaterial; Turkevich method; characterization
Online: 22 May 2023 (10:03:26 CEST)
The gold nanoparticle (AuNP) was synthesized using the well-known Turkevich method. This article explains didactic step-by-step of the synthesis, showing pictures of the entire process, including a well-explained mechanism and characterization study. The synthesis includes the reduction of NaAuCl4 using sodium citrate in high temperature (around 90 ⁰C). The two main mechanisms used to explain the AuNP synthesis via Turkevich method were explained. The first mechanism considerate that a nanowire intermediary and the other proposed that aggregate intermediates are not formed at any time during the synthesis. The materials (NaAuCl4 and AuNP) were characterized by UV-Vis, SEM, AFM, XRD and DLS. The UV-Vis exhibit an absorption maximum in 521 nm because the surface plasmon resonance (SPR) absorption band of AuNP. The SEM images of NaAuCl4 presents crystals with cubic shapes, while the AuNP presents average particle size of about 16-25 nm and particles that appear mainly spherical. To confirm the particles shapes, the AFM was conducted and it was possible to observe clearly the individual spherical nanoparticles. The XRD of AuNP showed the four main characteristic peaks for silver corresponding to (111), (200), (220) and (311) planes, confirming the cubic (FCC) silver. The DLS presented the average particle size of 3.3 ± 0.9 nm and the polydispersity index (PDI) of 0.574. In summary, the AuNP was synthesized using a simple and fast method. The result was a spherical and ultrasmall particle, that can be used is several applications.
ARTICLE | doi:10.20944/preprints202105.0529.v1
Subject: Chemistry And Materials Science, Biomaterials Keywords: Electrospun nanocomposite fiber; nanomechanical characterization, epoxy nanocomposites.
Online: 21 May 2021 (15:30:44 CEST)
The reinforcing effect of boehmite nanoparticles (BNP) in epoxy resins for fiber composite lightweight construction is related to the formation of a soft but bound interphase between filler and polymer. The interphase is able to dissipate crack propagation energy and consequently increases the fracture toughness of the epoxy resin. Usually, the nanoparticles are dispersed in the resin and then mixed with the hardener to form an applicable mixture to impregnate the fibers. If one wishes to locally increase the fracture toughness at particularly stressed positions of the fiber-reinforced polymer composites (FRPC), this could be done by spraying nanoparticles from a suspension. However, this would entail high costs for removing the nanoparticles from the ambient air. We propose that a fiber fleece containing bound nanoparticles be inserted at exposed locations. For the present proof-of-concept study, an electrospun polycarbonate nonwoven and taurine modified BNP are proposed. After fabrication of suitable PC/EP/BNP composites, the thermomechanical properties were tested by dynamic mechanical analysis (DMTA). Comparatively, the local nano-mechanical properties such as stiffness and elastic modulus were determined by atomic force microscopy (AFM). An additional investigation of the distribution of the nanoparticles in the epoxy matrix, which is a prerequisite for an effective nanocomposite, is carried out by scanning electron microscopy in transmission mode (TSEM). From the results it can be concluded that the concept of carrier fibers for nanoparticles is viable.
ARTICLE | doi:10.20944/preprints202103.0384.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: Biodegradable plastic; Biodegradation; Characterization; Extraction; Kinetics; Production.
Online: 15 March 2021 (13:12:28 CET)
The present study was aimed to evaluate the suitability of agro-wastes and crude vegetable oils for the cost effective production of poly-β-hydroxybutyrate (PHB), to evaluate growth kinetics and PHB production in Alcaligenes faecalis RZS4 and Pseudomonas sp. RZS1 with these carbon substrates and to study the biodegradation of PHB accumulated by these cultures. Alcaligenes faecalis RZS4 and Pseudomonas sp. RZS1 accumulate higher amounts of PHB corn (79.90% of dry cell mass) and rice straw (66.22% of dry cell mass) medium respectively. The kinetic model suggests that the Pseudomonas sp. RZS1 follows the Monod model more closely than A. faecalis RZS4. Both the cultures degrade their own PHB extract under the influence of PHB depolymerase. Corn waste and rice straw appear as the best and cost-effective substrates for the sustainable production of PHB from Alcaligenes faecalis RZS4 and Pseudomonas sp. RZS1. The biopolymer accumulated by these organisms is biodegradable in nature. The agro-wastes and crude vegetable oils are good and low cost sources of nutrients for the growth and production of PHN and other metabolites. Their use would lower the production cost of PHN and the low cost production will reduce the sailing price of PHB based products. This would promote the large scale commercialization and popularization of PHB as ecofriendly bioplastic/biopolymer.
ARTICLE | doi:10.20944/preprints201912.0169.v1
Subject: Engineering, Civil Engineering Keywords: mortar mosaic; volubilis; characterization; mineralogical; testing; mechanical.
Online: 12 December 2019 (09:59:49 CET)
The objective of this study is to conduct a mineralogical and chemical characterization of the mortars Roman archaeological site of Volubilis to rebuild spare mortars for restoration. We take samples of mortar, broken tile palate garden, and pavement mosaic Falavius Germanus houses. The analysis by X-ray diffraction reveals the coarse mortar Flavius Germanus is made of quartz and calcite with feldspar and probably, mica and dolomite in small amounts. The binder end is formed calcite and quartz. However, the broken tile mortar is formed by coarse particles, clay base mixed with a binder phase dominated by calcite. These results allowed us to reformulate spare mortars for the restoration of damaged Roman mosaics. The mortars are made up by 63.6% of lime and 36.4% of sand(with 4.19% of large grain, 71, 04% of coarse sand, 24.22%, of fine sand and 0.55% fines parts).The performance of these mortars was tested by mechanical testing.
ARTICLE | doi:10.20944/preprints201804.0279.v1
Subject: Biology And Life Sciences, Virology Keywords: Betaflexiviridae; blackcurrant; blackcurrant virus A; characterization; detection
Online: 23 April 2018 (10:37:14 CEST)
A novel virus with distinct genome features was discovered by high throughput sequencing in a symptomatic blackcurrant plant. The virus tentatively named as blackcurrant virus A (BCVA) has distinct genome organization and molecular features bridging genera in the order Tymovirales. The genome consists of 7106 nucleotides excluding the poly(A) tail. Five open reading frames were identified with the first encoding a putative viral replicase with methyl transferase (MTR), AlkB, helicase and RNA dependent RNA polymerase (RdRp) domains. The other four putative proteins exhibit no significant homology to other virus proteins. The genome organization downstream of the replicase resembles that of members of the order Tymovirales with an unconventional triple gene block (TGB) movement protein arrangement. Phylogenetic analysis using replicase conserved motifs loosely placed BCVA within the Betaflexiviridae whereas it was evolutionarily distant to existing members of the family when using the putative TGBp 1-like and coat protein sequences. Our analysis strongly suggests that BCVA is a novel virus that should be classified as a species in a new genus in the Betaflexiviridae or a new family in the order Tymovirales.
ARTICLE | doi:10.20944/preprints201610.0112.v1
Subject: Engineering, Chemical Engineering Keywords: silver; dissolution; thiosulfate; characterization; complex; temperature; arsenic
Online: 26 October 2016 (10:26:54 CEST)
Metallic elements of higher economic value occurring in the mineralogy of Zimapán are Pb, Zn, Cu and Fe, said elements are sold as concentrates, which, even after processing, generally include significant concentrations of Mo, Cd, Sb, Ag and As that could recover through different leaching methods. In this work the influence of temperature was studied in the complexation of silver in the S2O32--O2 system. Chemical and mineralogical characterization of concentrated Zn from the state of Hidalgo confirmed the presence of the silver contained in a sulfide of silver arsenic (AgAsS2) through the techniques of Atomic Absorption Spectrophotometry (AAS), X-Ray Diffraction (XRD) and Scanning Electron Microscopy-Energy-Dispersive X-Ray Spectroscopy (SEM-EDS). The mineralogical species identified allowed the construction mineralogical species Pourbaix diagrams in the range of 298 K to 333 K, through which the Eh-pH conditions to obtain silver in solution were determined. The formation of Ag(S2O3)23- complex was confirmed by characterizing liquors leached using the technique Infrared Spectroscopy Fourier Transform (FTIR).
ARTICLE | doi:10.20944/preprints202309.2043.v1
Subject: Biology And Life Sciences, Animal Science, Veterinary Science And Zoology Keywords: Avipoxvirus; molecular characterization; phylogenetic analysis; viral introduction; Portugal
Online: 29 September 2023 (08:32:26 CEST)
Avipoxvirus (APV), a linear dsDNA virus belonging to the subfamily Chordopoxvirinae of the family Poxviridae, infects more than 278 species of domestic and wild birds. It is responsible for causing the avian pox disease, which is characterized by its cutaneous and diphtheric forms. With a high transmission capacity, it can cause high economic losses and damage to the ecosys-tem. Several diagnostic methods are available and vaccination of birds can be an effective pre-ventive measure. To update the molecular characterization and phylogenetic analysis of viruses isolated in Portugal between 2017 and 2023, ten APV-positive samples were analyzed. A P4b gene fragment was amplified by PCR and the nucleotide sequence of the amplicons was deter-mined by Sanger sequencing. The sequences obtained were aligned using ClustalW, and a max-imum likelihood phylogenetic tree was constructed. With this study, it was possible to verify that the analyzed sequences are distributed in subclades A1, A2, B1, and B3. Since some of them are quite similar to others from different countries and obtained in different years, it is possible to conclude that there have been several viral introductions in Portugal. Finally, it was possible to successfully update the data on avipoxviruses in Portugal.
ARTICLE | doi:10.20944/preprints202303.0303.v1
Subject: Chemistry And Materials Science, Polymers And Plastics Keywords: Synthesis; characterization; carbonization; coagulation; bio char; nanocarbon; morphological
Online: 16 March 2023 (10:35:30 CET)
This work aimed to study the thermal and crystalline properties of poly (1,4-phenylene sulfide)@carbon char nanocomposites. Coagulation-processed nanocomposites of polyphenylene sulfide were prepared using synthesized mesoporous nanocarbon of coconut shell as reinforcement. The mesoporous reinforcement was synthesized using a facile carbonization method. The investigation of the properties of nanocarbon was done by SAP, XRD, and FESEM analysis. The research was further propagated via the synthesis of nanocomposite by the addition of characterized nanofiller into poly (1,4-phenylene sulfide) at five different combinations. The coagulation method was utilized for the nanocomposite formation. The obtained nanocomposite was analyzed using FTIR, TGA, DSC, and FESEM analysis. The BET surface area and average pore volume of bio-carbon prepared from coconut shell residue were calculated to be 1517 m2/g and 2.51 nm respectively. The addition of nanocarbon to poly (1,4-phenylene sulfide) has led to an increase in thermal stability and crystallinity up to 6% loading of filler. The minimum achievable glass transition temperature is for 6 % doping of filler into the polymer matrix. It was established that the thermal, morphological, and crystalline properties have been tailored by synthesizing their nanocomposites with mesoporous bio-nanocarbon obtained from coconut shells. So, the loading of filler into poly (1,4-phenylene sulfide) can be optimized to enhance its thermoplastic properties for surface applications.
ARTICLE | doi:10.20944/preprints202211.0195.v1
Subject: Medicine And Pharmacology, Veterinary Medicine Keywords: EHDV; Tunisia; virus characterization; EHDV serotype 8; circulation
Online: 10 November 2022 (09:59:16 CET)
Epizootic haemorrhagic disease (EHD) is a Culicoides-borne viral disease caused by epizootic haemorrhagic disease virus (EHDV) and associated with clinical manifestations in cervids and bovids. In late September 2021, EHDV was reported in cattle farms in central/western Tunisia. It rapidly spread throughout the country with more than 200 confirmed outbreaks. A combination of classical and molecular techniques was applied to characterize the causative virus as a member of EHDV-8 serotype. This is the first evidence of EHDV- 8 circulation since 1982 when the prototype EHDV-8 strain was isolated in Australia. This work highlights the urgent need for vaccines for a range of EHDV serotypes.
ARTICLE | doi:10.20944/preprints202205.0139.v1
Subject: Chemistry And Materials Science, Theoretical Chemistry Keywords: DESs; polarity; hydrophobicity; contact angle; solvatochromism; materials characterization
Online: 10 May 2022 (10:26:38 CEST)
The paper presents a new procedure for assessing the polarity and hydrophobicity of deep eutectic solvents (DESs) based on the measurement of the DES contact angle on glass. DESs consisting of benzoic acid derivatives and quaternary ammonium chlorides – tetrabutylammonium chloride (TBAC) and benzyldimethylhexadecylammonium chloride (16-BAC) in selected mole ratios were chosen for the study. To investigate the DESs polarity, an optical goniometer and an ET(30) solvatochromic scale based on the Reichardt’s dye were used. The research demonstrated the high accuracy and precision of the developed procedure. The simplicity of the examination and the availability of basic equipment allow the implementation of the developed procedure in routine investigations of DESs.
ARTICLE | doi:10.20944/preprints202009.0451.v1
Subject: Chemistry And Materials Science, Polymers And Plastics Keywords: adherence; adhesion; surface tackiness; PDMS; characterization; organo sheet
Online: 19 September 2020 (08:28:08 CEST)
Damage and fibre misalignment of woven fabrics during discontinuous polymer processing remain challenging. To overcome these, a promising switchable elastomeric adherence gripper is introduced here. The inherent surface tackiness is utilized for picking and placing large sheets. Due to the elastomer’s viscoelastic material behavior, the surface properties depend on loading speed and temperature. Different peeling speeds result in different adherence strength of an interface between the gripper and the substrate. This feature is mechanically characterized and the viscoelastic behavior of the stamp is examined. Based on this experimental characterization, an empirical model is proposed. Furthermore, a discussion of the applicability and limitation of the elastomeric gripper is given.
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: cathepsins; cancer; characterization; cysteine; Escherichia coli; expression; molecular
Online: 27 November 2019 (11:09:52 CET)
Cysteine cathepsins, a class of proteinaceous enzymes, regulate a wide variety of metabolic processes in human including protein breakdown and turnover and immune functions. Eleven cysteine cathepsins have been identified so far and a wide array of studies related to identifying their specific functions, regulation and distribution patterns in tissues have been conducted. However, in recent past, the association of cysteine cathepsins in occurrence and progression of cancers have been identified and this has caused unrest in scientists triggering them to investigate the physiology, biochemical pathways and interactions of these cathepsins in cancer metastasis and therefore has become a noteworthy topic of intensive research. This review focusses and collects together the published work on molecular functional and structural characterization studies that have been done so far on in vitro expression of genes encoding for cysteine cathepsins in the Escherichia coli bacterial expression system. Accordingly, it was found out that all cathepsins except for cathepsins K, C, H, X and W have been expressed this way and the majority of them were found to be expressed in E. coli BL21(DE3) pLysS expression host via pET3 expression vector. In addition, it was also noted that in most of the expression studies, the substrate that was used to validate the enzymatic activity of the recombinant enzyme that was produced was a cysteine residue along with a benzyloxy-carbonyl salt. Through this review, the authors suggest that there is a very high need that all cysteine cathepsins need to be characterized both structurally and functionally on a molecular platform to better understand their interactions including the biochemical pathways. It is also momentous that the mass production of the recombinant forms of these enzymes are facilitated via expression in such bacterial expression systems and in turn, would also provide a strong platform for the development and progression of studies related to human physiology including oncological studies such as cancer metastasis. Moreover, as per biochemical features of the enzymes that could be identified, the production of efficient inhibitors or inducers as per the necessity to improve health and promote wellbeing among the mankind could be facilitated.
ARTICLE | doi:10.20944/preprints201907.0334.v1
Subject: Engineering, Mechanical Engineering Keywords: polycrystals; ultrasonics; scattering; characterization; microstructure; Earth's internal core
Online: 29 July 2019 (10:35:51 CEST)
This work is a natural extension of the author’s previous work: “Multiple scattering theory for heterogeneous elastic continua with strong property fluctuation: theoretical fundamentals and applications” (arXiv:1706.09137 [physics.geo-ph]), which established the foundation for developing multiple scattering model for heterogeneous elastic continua with either weak or strong fluctuations in mass density and elastic stiffness. Polycrystalline material is another type of heterogeneous materials that widely exists in nature and extensively used in industry. In this work, the corresponding multiple scattering theory for polycrystalline materials with randomly oriented anisotropic crystallites is developed. To validate the theory, the theoretical results for a series of materials such as OFHC copper, 304 stainless steel, and Inconel 600 are compared to experimental measurements and the numerical results obtained using finite element simulations. Detailed analysis shows that the new theory is capable of predicting the dispersion and attenuation of polycrystals with satisfactory accuracy. The results also show the new model can give an estimate on the average grain size with a relative error equal to or less than ten percent. As applications in ultrasonic nondestructive evaluation, we calculated the dispersion and attenuation coefficient of one of the most important polycrystalline materials in aeronautics engineering: high-temperature titanium alloys. The effects of grain symmetry, grain size, and alloying elements on the dispersion and attenuation behaviors are examined. Key information is obtained which has significant implications for quantitatively evaluating the average grain size, monitoring the phase transition, and even estimating gradual change in chemical composition of titanium components in gas turbine engines. For applications in seismology, the velocities and Q-factors for both hexagonal and cubic polycrystalline iron models for the Earth’s uppermost inner core are obtained in the whole frequency range. Using the realistic material parameters of iron under the high temperature and high-pressure conditions calculated from ab initio simulations, the numerical results show that the Q-factors range from 0.001 to 0.05, which shows good agreement with that inferred from real seismic data. The new model predicts the velocity of longitudinal waves varies between ± 1% to ± 5 % relative to the Voight average velocity, while the velocity of transverse waves varies from ± 10% to ± 20%, which gives promising explanation to the abnormally slow transverse velocity observed in practical measurements. The numerical results support the conjecture that the Earth’s uppermost inner core is a solid polycrystalline medium. The comprehensive numerical examples show the new model is capable of capturing the most important scattering features of both ultrasonic and seismic waves with satisfactory accuracy. This work provides a universal, quantitative model for characterization of a large variety of polycrystalline materials. It also can be extended to incorporate more complicated microstructures, including ellipsoidal grains with or without textures, and even multi-phase polycrystalline materials. The new model demonstrates great potential of applications in ultrasonic nondestructive evaluation and inspection of aerospace and aeronautic structures. It also provides a theoretical framework for quantitative seismic data explanation and inversion for the material composition and structural formations of the Earth’s inner core.
ARTICLE | doi:10.20944/preprints201812.0050.v1
Subject: Medicine And Pharmacology, Pharmacology And Toxicology Keywords: Semen Allii Fistulosi; protein; extraction; characterization; antioxidant activity
Online: 4 December 2018 (09:32:34 CET)
Semen Allii Fistulosi is the seed of Allium fistulosum L. of the Liliaceae family. The purpose of this study was to extract, characterize, and evaluate the antioxidant activity in vitro of proteins from Semen Allii Fistulosi (PSAF). Using single factor and orthogonal design, the optimum conditions of extraction were determined to be as follows: extraction time 150 min, pH 8.5, temperature 60℃, and ratio (v/w, mL/g) of extraction solvent to raw material 35. The isoelectric point of the pH was determined to be about 4.4 and 10.2, by measuring the protein content of PSAF solutions at different pH. The amino acid composition of PSAF was determined by high performance liquid chromatography (HPLC), and the results suggested that the species of amino acids contained in the PSAF was complete. Sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS–PAGE) analysis showed the molecular weight was mainly between 40 and 55 kDa, and Fourier-transform infrared spectroscopy (FTIR) characterized prevalent protein absorption peaks. PSAF exhibited potent scavenging activities against DPPH assays, via targeting of hydroxyl and superoxide radicals, while chelating Fe2+ activity, and demonstrating weak reducing power. This work revealed that PSAF possessed potential antioxidant activity in vitro, suggesting potential for use of PSAF as a natural antioxidant.
ARTICLE | doi:10.20944/preprints201809.0237.v1
Subject: Environmental And Earth Sciences, Geophysics And Geology Keywords: reservoir characterization; Bayesian inversion; A-priori statistical models
Online: 13 September 2018 (12:05:12 CEST)
We discuss the influence played by different statistical models in the prediction of porosity and litho-fluid facies from logged and post-stack inverted acoustic impedance (Ip) values. We compare the inversion and classification results obtained under three different a-priori statistical assumptions: an analytical Gaussian distribution, an analytical Gaussian-mixture model and a non-parametric mixture distribution. The first model assumes Gaussian distributed porosity and Ip values, thus neglecting their facies-dependent behaviour caused by different lithologic and saturation conditions. Differently, the other two statistical models relate each component of the mixture to a specific litho-fluid facies, so that the facies-dependency of porosity and Ip values is taken into account. Blind well tests are used to validate the final predictions, whereas the analysis of the maximum-a-posteriori (MAP) solutions, the coverage ratio and the contingency analysis tools are used to quantitatively compare the inversion outcomes. This work points out that the correct choice of the statistical petrophysical model could be crucial in reservoir characterization studies. Indeed, for the investigated zone it turns out that the simple Gaussian model constitutes an oversimplified assumption, while the two mixture models provide more accurate results, although the non-parametric one yields slightly superior predictions with respect to the Gaussian-mixture assumption.
ARTICLE | doi:10.20944/preprints201708.0033.v1
Subject: Engineering, Chemical Engineering Keywords: petroleum sludge; characterization; total organic carbon; metal concentration
Online: 8 August 2017 (13:24:39 CEST)
Thermal plasma technique is becoming prominent in the treatment of variety of waste ranging from municipal solid waste, incinerator residue, hospital waste, electronics waste and industrial sludge. Application of the new treatment technology to petroleum sludge requires information on the nature and characteristics of the sludge that will be use to optimize the treatment system. In this investigation, petroleum sludge obtained from Petronas Melaka was characterized for its physical and chemical features. Proximate and ultimate analysis as well as determination of elemental composition were carried out. The sludge was found to contain high moisture (78.91%), low ash (5.06%), low volatiles (5.52%) and high fixed carbon (10.51%). The sludge has a TOC of 54.48% and HHV of 23.599MJ/kg. Despite the high moisture content, the higher heating value (HHV) is high when compared to literature values. The high value of HHV may be associated with the high fixed carbon, low ash content and high value of TOC. The apparent density of the sludge is slightly lower. Fourteen heavy metals are detected in significant quantities. Proper waste management that will safely dispose the sludge is required. The waste disposal technique should take into cognizant the possibility of leaching of heavy metals into ground water on one hand and the gasification of lighter ones on the other.
ARTICLE | doi:10.20944/preprints201705.0036.v2
Subject: Engineering, Energy And Fuel Technology Keywords: solar PV; module; degradation; characterization; I-V curve
Online: 10 May 2017 (04:32:43 CEST)
Fourteen (14) rack-mounted polycrystalline modules installed on the concrete roof of the solar energy applications laboratory at the Kwame Nkrumah University of Science and Technology (KNUST) in Ghana, a hot humid environment were assessed after 19 years of continuous outdoor expodure. The physical state of the modules was documented using a visual inspection checklist. They were further assessed by current-voltage (I-V) characterization and thermal imaging. The modules were found to be in good physical state, except some bubbles on front side and minor discolouration/corrosion at edge of the cells. Compared with reference values, the performance decline of the modules observed over the exposure period was: nominal power (Pnom), 21% to 35%; short circuit current (Isc), 5.8% to 11.7%; open circuit voltage (Voc) 3.6% to 5.6% and 11.9% to 25.7% for fill factor (FF). It is hoped that this study will provide some helpful information to project developers, manufacturers and the research community on the long-term performance of PV modules in Ghana.
ARTICLE | doi:10.20944/preprints201703.0056.v1
Subject: Chemistry And Materials Science, Chemical Engineering Keywords: Ag/MgAl2O4; characterization; activity; Photocatalytic degradation; Methylene blue
Online: 10 March 2017 (10:37:46 CET)
In the present work report, the MgAl2O4and the Ag/MgAl2O4 samples were successfully synthesized by the modified hydrothermal and the isovolumetric impregnation methods, respectively. The structural properties of the prepared samples were systematically characterized by XRD, SEM, TEM, DRS, XPS and et al techniques. The photocatalytic degradation of methylene blue by the Ag/MgAl2O4 and MgAl2O4 samples was comparatively studied under UV lamp irradiation. The results revealed that the prepared Ag/MgAl2O4 (pH=6) samples were the most active among the samples in photocatalytic of methylene blue. Under UV lamp irradiation, the Ag/MgAl2O4 (pH=6) photodegradation of methylene blue reached to 89.6% within 120 min. And the Ag/MgAl2O4 (pH=6) complex photocatalysts displayed a high photochemical stability under repeated irradiation. Repeated irradiate the Ag/MgAl2O4 (pH=6) compound, which indicated it had a high photochemical stability.
ARTICLE | doi:10.20944/preprints201612.0110.v1
Subject: Chemistry And Materials Science, Applied Chemistry Keywords: arylpiperazine compound; X-ray crystal structure; characterization; triclinic
Online: 21 December 2016 (11:01:58 CET)
The structure of arylpiperazine moieties as an important pharmacophore could generate wide pharmacological activities．Arylpiperazine derivatives referred in this paper possessed antitumor activity. The title compounds were crystallized by slow evaporation. 2-(4-(2-(4-Phenylpiperazin-1-yl)ethyl)benzyl)isoindoline-1,3-dione(1), 2-(4-(2-(4-(4-Bromophenyl)piperazin-1-yl)ethyl)benzyl)isoindoline-1,3-dione (2) and 2-(4-(2-(4-(4-Chlorophenyl)piperazin-1-yl)ethyl)benzyl)isoindoline-1,3-dione (3) crystallizes in the triclinic space group P-1 with two molecules in the unit cell. The unit cell parameters for 1 are a = 6.9159(14) Å, b = 9.999(2) Å, c = 16.925(3) Å, α = 88.25(3)°, β = 85.14(3) °, γ = 79.22(3) °. The unit cell parameters for 2 are a = 6.9995(14) Å, b = 9.919(2) Å, c = 17.671(4) Å, α= 97.55(3)°, β = 92.19(3) °, γ = 102.23(3) °. The unit cell parameters for 1 are a = 6.9872(14) Å, b = 9.863(2) Å, c = 17.557(4) Å, α=96.81(3)°, β = 91.89(3) °, γ = 101.74(3) °. Pi-pi interactions were observed between molecules, and compound 2 and 3 showed halogen interactions between molecules nearby, which was different from compound 1.
ARTICLE | doi:10.20944/preprints202311.1808.v1
Subject: Biology And Life Sciences, Food Science And Technology Keywords: Agrocybe aegerita; Hygrophorus olivaceoalbus; polysaccharide; structure characterization; biological activities.
Online: 28 November 2023 (11:47:02 CET)
The structure characterization of two new polysaccharides from Agrocybe aegerita (AA-P) and Hygrophorus olivaceoalbus (HO-P) by HPGPC, GC-MS, NMR and FT-IR indicated that AA-P was composed of Galactose, Glucose and Arabinose, in the ratio of 3:2:1. Its skeleton structure was consisted of (1→4)-Arap, (1→4,6)-Glup and (1→6)-Galp with one branched chain. The HO-P was consisted of mannose, galactose and glucose in a ratio of 1:1:2. Its skeleton structure was consisted of (1→6)-Galactose residues, (→1)-glucose residues, (1→4)-glucose residues and (1→4,6)-D-mannose residues. There were two branched chains connected to the main chain. AA-P and HO-P had the best stimulation effect on B cells and RAW264.7 cells, respectively, and could both mainly by impacting and reducing G0/G1 phase which lead to a significant proliferation of B cells, T cells and RAW264.7 cells. In addition, AA-P and HO-P could significantly promote the secretion of TNF-α from T cells, the secretion of IgA, IgD, IgE, IgG and IgM from B cells, and the secretion of TNF-α from RAW264.7 cells, but neither of them could impact the secretion of IL-1β from RAW264.7 cells.
REVIEW | doi:10.20944/preprints202310.0446.v1
Subject: Chemistry And Materials Science, Physical Chemistry Keywords: bimetallic single-atom; characterization; catalytic mechanism; hydrogen evolution reaction
Online: 8 October 2023 (11:59:21 CEST)
Electrocatalytic and photocatalytic hydrogen evolution reaction (HER) provides a promising approach to clean energy generation. Bimetallic single-atom catalysts raised and have been explored to be advanced catalysts for HER. It is urgent to review and summarize the recent advances in developing bimetallic single-atom HER catalysts. Firstly, the fundamentals of bimetallic single-atom catalysts are presented, highlighting their unique configuration of two isolated metal atoms on supports and resultant synergistic effects. Secondly, recent advances in bimetallic single-atom catalysts for electrocatalytic HER under acidic/alkaline conditions are then reviewed, including W-Mo, Ru-Bi, Ni-Fe, Co-Ag, and other dual-atom systems on graphene and transition metal dichalcogenides (TMDs) with enhanced HER activity versus monometallic analogs due to geometric and electronic synergies. Then, Photocatalytic bimetallic single-atom catalysts on semiconducting carbon nitrides for solar H2 production are also discussed. Finally, an outlook is provided on opportunities and challenges in precisely controlling bimetallic single-atom catalyst synthesis and gaining in-depth mechanistic insights into bimetallic interactions.
ARTICLE | doi:10.20944/preprints202309.2166.v1
Subject: Biology And Life Sciences, Biology And Biotechnology Keywords: L-asparaginase II; Bacillus subtilis; saline environment; biochemical characterization
Online: 30 September 2023 (08:39:19 CEST)
L-asparaginase from bacterial sources have been used in antineoplastic treatments and the food industry. A novel type II L-a sparaginase encoded by the N-truncated gene ansZP21 of halotolerant Bacillus subtilis CH11 isolated from Chilca salterns in Peru was expressed using a heterologous system in Escherichia coli BL21 (DE3)pLysS. The recombinant protein was purified using one-step nickel affinity chromatography and exhibited activity of 234.38 U mg-1 and a maximum catalytic activity at pH 9.0 and 60 °C. The enzyme shows a homotetrameric form with an estimated molecular weight of 155 kDa by gel filtration chromatography. The enzyme half-life at 60 °C was 3 h 48 min, and L-asparaginase retained 50% of initial activity for 24 h at 37 °C. The activity was considerably enhanced by KCl, CaCl2, MgCl2, mercaptoethanol, and DL-dithiothreitol (p-value < 0.01). Moreover, the Vmax and Km were 145.2 µmol mL-1 min-1 and 4.752 mM, respectively. These findings evidence a promising novel type II L-asparaginase for future industrial applications.
ARTICLE | doi:10.20944/preprints202308.1137.v1
Subject: Public Health And Healthcare, Public, Environmental And Occupational Health Keywords: Rotavirus A; Reassortment; Interspecies transmission; Genomic characterization; Porcine; Zambia
Online: 16 August 2023 (04:19:03 CEST)
Rotavirus is a major cause of diarrhea globally in animals and young children under 5 years. Here, molecular detection and genetic characterization of porcine rotavirus in smallholder and commercial pig farms in the Lusaka Province of Zambia were con-ducted. Screening of 148 stool samples by RT-PCR targeting the VP6 gene revealed a prevalence of 22.9 % (34/148). Further testing of VP6-positive samples with VP7-specific primers produced 12 positives, which were then Sanger-sequenced. BLASTn of the VP7 positives showed sequence similarity to porcine and human rota-virus strains with identities ranging from 87.5% to 97.1%. By next-generation se-quencing, the full-length genetic constellation of the representative strains RVA/pig-wt/ZMB/LSK0137 and RVA/pig-wt/ZMB/LSK0147 were determined. Geno-typing of these strains revealed a known Wa-like genetic backbone and their genetic constellations were G4-P-I5-R1-C1-M1-A8-N1-T1-E1-H1 and G9-P-I5-R1-C1-M1-A8-N1-T1-E1-H1, respectively. Phylogenetic analysis revealed that these two viruses might have their ancestral origin from pigs, though some of their gene segments were related to human strains. The study shows evidence of reas-sortment and possible interspecies transmission between pigs and humans in Zambia. Therefore, the “One Health” surveillance approach for rotavirus A in animals and humans is recommended to inform the design of effective control measures.
ARTICLE | doi:10.20944/preprints202305.1321.v1
Subject: Chemistry And Materials Science, Medicinal Chemistry Keywords: Abricó de macaco; antioxidant potential; chemistry characterization; dentistry; microbiology
Online: 18 May 2023 (10:08:10 CEST)
The study of phytotherapy in dentistry is relevant due to the low occurrence of research in the treatment of oral pathologies, such as caries and periodontal disease. Thus, the aim of this research was to characterize the chemical composition of extracts from the leaves of Couroupita guianensis Aubl, including toxicological evaluation and the antioxidant and antimicrobial potential against Staphylococcus aureus, Streptococcus mutans and Candida albicans. Three extracts were prepared using assisted ultrasound, originating the Crude Ultrasound Extract (CUE) and Soxhlet apparatus, originating the Crude Soxhlet Extract (CSE) and the Ethanol Soxhlet Extract (ESE). In the analysis of the chemical composition, the presence of flavonoids, tannins and saponins were detected. LC-DAD analysis revealed the presence of caffeic acid, sinapic acid, rutin, quercetin, luteolin, kaempferol and apigenin in all extracts. In the GC-MS analysis, stigmasterol and β-sitosterol were identified in CUE and CSE. The antioxidant potentials, determined by the DPPH• and ABTS•+ methods, the ESE showed higher antioxidant activity (2.98 ± 0.96 and 4.93 ± 0.90, respectively). In the evaluation of toxicity, the CUE 50µg/mL and the ESE 50 µg/mL presented growth stimulation of Allium cepa roots. At a concentration of 750µg/mL, all extracts inhibited root growth. None of the extracts showed toxicity against Artemia salina. Antibacterial action was detected in all extracts, mainly against the microorganisms S. aureus and S. mutans; however, the antifungal action against C. albicans was not detected. From the results, the extracts of C. guianensis have therapeutic potential for use in the control of microorganisms in the oral microbiota.
ARTICLE | doi:10.20944/preprints202304.0296.v1
Subject: Environmental And Earth Sciences, Environmental Science Keywords: biochar; crop straws; heavy metal adsorption; adsorption kinetics; characterization
Online: 13 April 2023 (05:08:11 CEST)
China is a large agricultural country that produces a large amount of crop straw every year. Thus, the development of cost-effective and economic application of invasive plants is warranted. Biochars derived from crop straw has been proven to be promising for adsorbent materials. However, less studies have focused on biochar derived from different types of crop straw as adsorbent under the same conditions to compare their adsorption performance. Here, we characterized the five biochars in the same system (600 ℃). In results, GBC has higher ash content, pH, CEC, specific surface area, mineral composition and oxygen-containing functional groups. The adsorption kinetics can be explained adequately by pseudo-second-order model and Langmuir model, indicating that the adsorption behavior of the biochar is both physical adsorption and chemical adsorption, the adsorption process includes complexation reaction, cationic π bond, ion precipitation and electrostatic adsorption. In conclusion, GBC exhibited higher metal equilibrium adsorption capacities (125 mg·g-1 for Pb2+, 29 mg·g-1 for Cd2+). The solution pH, biochar dosing, pyrolysis temperature and the properties of these heavy metals were responsible for adsorption capacity, thus showing stronger affinity and better adsorption effect. Our results are important for the selection and utilization of plant-based biochar for different heavy metals.
ARTICLE | doi:10.20944/preprints202301.0251.v1
Subject: Medicine And Pharmacology, Orthopedics And Sports Medicine Keywords: laser beam characterization; laser therapy; medical devices; sports medicine
Online: 13 January 2023 (10:51:11 CET)
Laser therapy devices (LTDs) operating with near-infrared laser light are increasingly being used in sports medicine. For several reasons the users cannot evaluate whether or not such devices emit laser beams according to the specifications provided by the manufacturer and the settings of the device. In this study the laser beams from two different LTDs that can be used in sports medicine were thoroughly characterized by measuring the emitted power, pulse shapes and lengths, and spatial intensity distributions using professional, high-fidelity laser measurement technology. This was repeated for three units of each LDT independently to distinguish problems of individual units from potential intrinsic instrument design errors. The laser beams from the units of one LTD agreed with the settings at the device, with the measured average power for these units being within 3.3% of the set power. In contrast, the laser beams from the units of the other LTD showed large deviations between the settings and the actual emitted light. This device came with three laser diodes that could be used independently and simultaneously. The average power differed greatly between the units as well as between the laser diodes within each unit. Some laser diodes emitted essentially no light, which could lead to a lack of treatment of patients. Other laser diodes emitted much more power than set at the device (up to 230%) that could result in skin irritations or burnings of patients. These findings indicate a need for better standardization and consistency of therapeutic laser light sources.
Subject: Chemistry And Materials Science, Biomaterials Keywords: computed tomography; 3D imaging; quantitative analysis; accurate morphometric characterization
Online: 15 October 2021 (12:12:47 CEST)
The ever-growing field of materials with applications in the biomedical field holds great promise regarding the design and fabrication of devices with specific characteristics especially scaffolds with personalized geometry and architecture. The continuous technological development pushes the limits of innovation in obtaining adequate scaffolds and establishing their characteristics and performance. To this end, computed tomography (CT) proved to be a reliable, non-destructive, high-performance machine, enabling visualization and structure analysis at sub-micronic resolutions. CT allows both qualitative and quantitative data of the 3D model, offering an overall image of its specific architectural features as well as reliable numerical data for rigorous analyses. The precise engineering of scaffolds consists in the fabrication of objects with well-defined morphometric parameters (e.g.: shape, porosity, wall thickness), and in their performance validation through thorough control over their behavior (in situ visualization, degradation, new tissue formation, wear, etc.). This review is focused on the use of CT in biomaterial science with the aim of qualitatively and quantitatively assess the scaffolds’ features and in monitoring their behavior following in vivo or in vitro experiments. Furthermore, the paper presents the benefits and limitations regarding the employment of this technique when engineering materials with applications in the biomedical field.
Subject: Chemistry And Materials Science, Biomaterials Keywords: Zinc nanoparticles; Plant extract; Green Synthesis; Characterization; Mechanism; Applications
Online: 28 May 2021 (09:58:44 CEST)
Background:Boom in nanotechnology in current era has sketched unforeseen transformations in number of fields, such as medicine, health care, food, space, agriculture, etc. The synthesis of nanoparticles with different chemical compositions, sizes, shapes and controlled disparities is an important area of research in this field. Over the last decade, the biosynthesis of metal nanoparticles has received considerable attention due to their unusual and fascinating properties, with various applications, over their bulk counterparts.Hypothesis: The nanoparticle can have huge application in the field of food, pharmaceutical, and cosmetic industries and thus become a major area of research. Green synthesis of zinc oxide nanoparticles (ZnO NPs) using plant extracts offers an eco-friendly and promising substitute to the conventional methods of chemical synthesis. Conclusion: In the arena of nanoparticle phytosynthesis, novel materials have been produced that are eco-friendly, cost-effective and stable. In the current situation, nanotechnology inspires progress in all spheres of life, and therefore the phytosynthetic path of nanoparticle synthesis has emerged as a safe and best alternative to conventional methods. This review summarizes the recent work in the field of zinc nanoparticle phytosynthesis and critically discusses the mechanism proposed behind it.
REVIEW | doi:10.20944/preprints202104.0069.v1
Subject: Biology And Life Sciences, Anatomy And Physiology Keywords: willow bark; chemical characterization; mechanism; broiler diet; heat stress
Online: 2 April 2021 (14:09:52 CEST)
Over the last decade, there has been a growing interest in the use of a wide range of phytoadditives to counteract the harmful effects of heat stress in poultry. Willow (Salix spp.) is a tree with a long history. Among various forms, willow bark is an important natural source of salicin, β-O-glucoside of saligenin, but also of polyphenols (flavonoids and condensed tannins) with antioxidant, antimicrobial and anti-inflammatory activity. In light of this, the current review presents some literature data aiming to: (1) describe the relationship between heat stress and oxidative stress in broilers, (2) present or summarize literature data on the chemical composition of Salix species, (3) summarize the mechanisms of action of willow bark in heat-stressed broilers, (4) present different biological effects of the extract of Salix species in different experimental models.
ARTICLE | doi:10.20944/preprints202103.0576.v1
Subject: Biology And Life Sciences, Anatomy And Physiology Keywords: Lactic acid bacteria; Traditional fermented milk; Isolation; Identification. characterization
Online: 24 March 2021 (09:58:43 CET)
Fermented milk product "Laban" in Libya is one of the most a traditional fermented milk product consumed a refreshing drink, particularly in the warm season The average values of the physicochemical including titratable acidity, pH, total solids, and fat were 0.73%, 4.16, 8.12%, and 1.54% respectively. Coliform, yeast and mold counts were 21×10⁴, 39×10⁴, and 41 ×10³ cfu/ ml., respectively. Most strains of coliform bacteria were Serratia odorifera, Escherichia coli 1, E. coli 2. and Klebsiella oxytoca. The average Lactococcus, Streptococcus, Mesophilic Lactobacillus / Leuconostoc and Thermophilic Lactobacillus counts were 99 ×10⁷, 96 ×10⁷, 93 ×10⁷ and 15 ×10⁷ cfu / ml. respectively. A total of 142 lactic acid bacteria (LAB) isolates were identified to the genus level as Lactobacillus (48.59%), Lactococcus (43.66%), Streptococcus (4.93%) and Leuconostoc (2.82%). Sugar fermentation tests revealed the most frequent Lactobacillus species found to be Lactobacillus delbrueckii ssp. lactis (62.32%), followed by Lactobacillus plantarum (31.88%). Furthermore, other selected LAB isolates were identified by API 50 CH test as Lactococcus lactis ssp. lactics, Lactobacillus pentosus, Lactobacillus brevis, and Leuconostoc mesenteroides ssp. cremoris. Thus, our research documented the lactic acid bacteria strains and will provides fundamental basic and useful information for further studies of strain selection starter culture, with regard to the industrial production of fermented dairy milk products.
REVIEW | doi:10.20944/preprints202003.0082.v1
Subject: Chemistry And Materials Science, Polymers And Plastics Keywords: ARM-IR; polymers; polymer blends; polymer aging; nanoscale characterization
Online: 5 March 2020 (04:03:23 CET)
Atomic force microscopy (AFM) has been extensively used for the nanoscale characterization of polymeric materials. The coupling of AFM with infrared spectroscope (AFM-IR) provides another advantage to the chemical analyses and thus helps to shed light upon the study of polymers. In this perspective paper, we review recent progress in the use of AFM-IR in polymer science. We describe first the principle of AFM-IR and the recent improvements to enhance its resolution. We discuss then the last progress in the use of AFM-IR as a super-resolution correlated scanned-probe IR spectroscopy for chemical characterization of polymer materials dealing with polymer composites, polymer blends, multilayers and biopolymers. To highlight the advantages of AFM-IR, we report here several results in studying crystallization of both miscible and immiscible blends as well as polymer aging. Then, we demonstrate how this novel technique can be used to determine phase separation, spherulitic structure and crystallization mechanisms at the nanoscale, which have never been achieved before. The review also discusses future trends in the use of AFM-IR in polymer materials, especially in polymer thin film investigation.
Subject: Biology And Life Sciences, Plant Sciences Keywords: Aspergillus sp.; extracellular laccase; production; purification; characterization; dye decolorization
Online: 8 December 2019 (17:24:19 CET)
Although laccase has been recognized as a wonder molecule, and green enzyme, the use of low yielding fungal strains, poor production, purification, and low enzyme kinetics have hampered its larger-scale applications. Hence the present research was aimed to select high yielding fungal strains and to optimize the production, purification, and kinetics of laccase of Aspergillus sp. HB_RZ4. Aspergillus sp. HB_RZ4 produced a copious amount of laccase on under meso-acidophillic shaking conditions in a medium containing glucose and yeast extract. A 25 µM of CuSO4 enhanced the enzyme yield. The enzyme was best purified on Sephadex G-100 column. Purified enzyme resembled with the laccase of A. flavus. Kinetics of purified enzyme revealed the high substrate specificity and good velocity of reaction with ABTS as substrate. The enzyme was stable over a wide range of pH and temperature. The peptide structure of the purified enzyme resembled with the laccase of A. kawachii IFO 4308. The fungus decolorized various dyes independent of the requirement of a laccase mediator system (LMS). Aspergillus sp. HB_RZ4 came out as a potent natural producer of laccase, it decolorized the dyes even in absence of LMS and thus can be used for bioremediation.
ARTICLE | doi:10.20944/preprints201809.0116.v1
Subject: Environmental And Earth Sciences, Geophysics And Geology Keywords: undifferentiated and wheathered deposits, thin layers, vs characterization, MASW
Online: 6 September 2018 (13:16:56 CEST)
The application of geophysical methods for the characterization of geomorphologic subsurface features has become very popular in recent years. Convential geophysical applications on undifferentiated and weathered slopes have been less effective. Multichannel analysis of surface waves (MASW) is a new hope for the solution of the problem. MASW methods was used to the first step in order to reconstruct the ancient eruption of Mount Samalas. MASW was applied to the remnants of ancient volcanic sediment on Lombok Island to determine the physical and physical characteristics of seismic subsurface features. This paper is also discussion the application's capabilities of the MASW method on undifferentiated and weathered volcanic deposits on the slope area and classified them. The results of the research show that MASW technique is powerful in characterizing and delineating the stratum of the layers of undifferentiated and weathered volcanic precipitation areas. MASW is able to predict subsurface structures, especially for shallow and thin layers and presenting site class information for internal structure (vertical resolution). Based on S wave velocity structure, undifferentiated and weathered volcanic layer, genes are classified into site class C, D, and E. In the future, this method will completed with combination of other geophysical method and parameters variation (frequency and spaces) for isopach mapping of volcanic sediment and then analysis of ancient volcanic eruption dynamics.
ARTICLE | doi:10.20944/preprints201711.0035.v1
Subject: Physical Sciences, Applied Physics Keywords: stress relaxation; polymer dynamics; biomechanical characterization; articular cartilage; osteoarthritis
Online: 6 November 2017 (06:44:18 CET)
Osteoarthritis (OA) is a common joint disorder found mostly in elderly people. The role of mechanical behavior in the progression of OA is complex and remains unclear. The stress-relaxation behavior of human articular cartilage in clinically defined osteoarthritic stages may have importance in diagnosis and prognosis of OA. In this study we investigated differences in the biomechanical responses among human cartilage of ICRS grades I, II and III using polymer dynamics theory. We collected 24 explants of human articular cartilage (eight each of ICRS grade I, II and III) and acquired stress-relaxation data applying a continuous load on the articular surface of each cartilage explant for 1180 s. We observed a significant decrease in Young’s modulus, stress-relaxation time, and stretching exponent in advanced stages of OA (ICRS grade III). The stretch exponential model indicated that significant loss in hyaluronic acid polymer might be the reason for the loss of proteoglycan in advanced OA. This work encourages further biomechanical modelling of osteoarthritic cartilage utilizing these data as input parameters to enhance the fidelity of computational models aimed at revealing how mechanical behaviors play a role in pathogenesis of OA.
ARTICLE | doi:10.20944/preprints201610.0059.v1
Subject: Engineering, Metallurgy And Metallurgical Engineering Keywords: ammonium–arsenic jarosite; characterization; chemical decomposition and thermal decomposition
Online: 14 October 2016 (11:27:36 CEST)
Arsenic, an element of environmental impact, can be incorporated into jarosite–type compounds and remain stabilised within the structure under a wide range of environmental conditions. In this study, a sample of ammonium–arsenic jarosite was synthesised by precipitation in sulphate medium at controlled pH of 1.2–1.8. The behaviour of arsenic during the thermal and chemical decomposition of jarosite was analysed; the degradation in alkaline medium of jarosite was also studied. According to the results, the synthesised jarosite is composed of joined rhombohedral crystals, forming tightly spherical shaped particles, 37–54 μm size. The ammonium jarosite produced possessed a high arsenic concentration; its calculated stoichiometry being (NH4)Fe2.45[(SO4)1.80(AsO4)0.20][(OH)4.15(H20)1.85]. It was found that arsenic is stabilised in the jarosite structure; upon heating, it remains in residual solids above 700°C, whilst in alkaline medium an incongruent dissolution takes place, with the arsenic retained in the solid phase along with iron. These solids, when exposed to high temperatures (1200°C), transform into a type of iron oxide known as hematite, so with arsenic it is retained an iron compound forming a stable compound which withstands high temperatures.
REVIEW | doi:10.20944/preprints202311.1355.v1
Subject: Public Health And Healthcare, Public, Environmental And Occupational Health Keywords: cancer; NK cells; macrophages; T cells; immunotherapy; molecular characterization
Online: 21 November 2023 (15:27:16 CET)
Tumors are complex tissues of malignant cells surrounded by a diverse cellular micro-environment with which they interact. The molecular and cellular underpinnings of cancer cells have been increasingly understood during the last few decades. Nonetheless, a great deal remains unknown regarding the ways in which tumour cells modify their surroundings and impact the organisation and makeup of cells. This review aims to concentrate on recent advancements in molecular characterization of tumor cells and its immunology, provides recent and general insight into cancer immunity and immunotherapy, and discusses the immunobiology of human adaptive and innate immunity to malignant growth of cancer cells, the mechanisms that support human immune response from beneath, an up-to-date scientific development to cancer immunotherapy, and how tumor and host responses can Encircle as a military tactic effective anti-cancer immunity.
ARTICLE | doi:10.20944/preprints202310.1370.v1
Subject: Biology And Life Sciences, Biology And Biotechnology Keywords: Xaa-Pro dipeptidase; Aspergillus phoenicis; reclassification; heterologous expression; biochemical characterization
Online: 20 October 2023 (16:14:13 CEST)
Xaa-Pro dipeptidase (XPD, EC 188.8.131.52; also known as prolidase) catalyzes the hydrolysis of iminopeptide bond in the trans Xaa-Pro dipeptides (Xaa represents any amino acid except proline), which makes it find wide applications in food, medical and environmental protection fields. In the present study, a novel Xaa-Pro dipeptidase from Aspergillus phoenicis ATCC 14332 (ApXPD) was molecularly and biochemically characterized. Reclassification based on phylogenetic analysis and version 12.5 MEROPS database showed that this enzyme was the only fungal XPD in the unassigned subfamily which shared the highest sequence similarity with Xanthomonas campestris prolidase but not with that from the more related fungal species A. niudulans. As compared with other prolidases, ApXPD also contained an N-terminal tail (residues 81-89) and an additional region (PAPARLREKL), and used a different arginine residue for dipeptide selectivity. After heterologous expression and partial purification, recombinant ApXPD was highly active and stable over the alkaline range from 8.5 to 10.0, with a maximum activity at pH 9.0 and more than 80% activity retained after 1-h incubation at pHs of 8.5-10.0 (55oC). It also had an apparent optimum temperature of 55oC and remained stable at 20-30oC. Moreover, this enzyme was a cobalt dependent prolidase that only cleaved dipeptides Lys-Pro, Gly-Pro and Ala-Pro rather than other dipeptides, tripeptides and tetrapeptides. All these distinct features make A. phoenicis ATCC 14332 XPD unique among currently known prolidases, thus defining a novel Xaa-Pro dipeptidase subfamily.
ARTICLE | doi:10.20944/preprints202310.0464.v1
Subject: Biology And Life Sciences, Animal Science, Veterinary Science And Zoology Keywords: Sracocystis cruzi; Sarcocystis poephagicanis; cattle; yak; morphological and molecular characterization
Online: 9 October 2023 (10:36:54 CEST)
Sracocystis cruzi in cattle (Bos taurus) and Sarcocystis poephagicanis in yaks (Bos grunniens) are morphologically indistinguishable. However, the relationship of the two parasites is still un-clear. Here, muscular tissues of the two domestic animals collected from abattoirs in China were examined for sarcocysts of S. cruzi and S. poephagicanis. The sarcocysts isolated from the samples were processed for light microscopy (LM), transmission electron microscopy (TEM), and DNA analysis. Sarcocysts of S. cruzi and S. poephagicanis were found in 405 of 950 (42.6%) cattle and 304 of 320 (95.0%) yaks, respectively. By LM and TEM, the sarcocysts of the two parasites showed similar morphologically characteristics. The thin-walled sarcocysts had hair-like protrusions on the surface. Ultrastructures exhibited the primary cyst wall contained irregularly folded, hirsute or bone-like protrusions. Four genetic markers, 18S rDNA, 28S rDNA, mitochondrial cox1, and apicoplast rpl6 of the two parasites were sequenced and analyzed. The sequences of the four loci presented an interspecific identity of 97.9−98.6%, 97.2−98.1%, 89.5−90.4%, and 96.9−97.2%, respec-tively. Phylogenetic analysis using 28S rDNA and cox1 sequences indicated that both species were placed into a group encompassing Sarcocystis spp. in ruminants with canid as known or putative definitive hosts. Sarcocystis cruzi and S. poephagicanis should represent separated species, and cox1 and rpl6 was suitable for distinguishing between them.
REVIEW | doi:10.20944/preprints202310.0345.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: Prostate cancer, SPOP mutations, Androgen Receptor, disease characterization, therapeutic targets
Online: 6 October 2023 (11:29:08 CEST)
Background: Prostate cancer is a global health concern, necessitating ongoing research to enhance our comprehension of its molecular foundations and develop more efficacious therapeutic approaches. Among the emerging protagonists in this arena is Speckle-type POZ (pox virus and zinc finger protein) (SPOP), an E3 ubiquitin ligase substrate adaptor protein. SPOP's recent ascent to prominence in prostate cancer research is attributed to its crucial role in regulating the Androgen Receptor (AR) signaling pathway. This systematic review aims to provide a comprehensive synthesis of existing knowledge concerning SPOP mutations in prostate cancer. It seeks to elucidate their significance in characterizing the disease and their potential as therapeutic targets. Methods: A systematic literature search was conducted in multiple databases, including PubMed, Web of science, Scopus and google scholar to identify relevant studies published up to September 2023. Eligible studies included investigations of SPOP mutations in prostate cancer and their implications. Data extraction, quality assessment, and synthesis were performed in conformity to the PRISMA guidelines. Results: The review revealed that SPOP mutations are recurrent events in prostate cancer, with a notable prevalence in specific molecular subtypes. These mutations primarily affect the MATH domain of SPOP, disrupting its substrate recognition function. Notably, SPOP mutations have profound consequences on the AR signaling pathway, leading to increased AR protein stability and transcriptional activity. The clinical implications of SPOP mutations remain diverse, with varying associations with prognostic outcomes. Conclusion: SPOP mutations represent a significant facet of prostate cancer biology, influencing disease heterogeneity and clinical behavior. While their precise prognostic significance is evolving, their functional impact on the AR pathway highlights their potential as therapeutic targets. This systematic review provides a comprehensive overview of SPOP mutations in prostate cancer, contributing to our understanding of the disease's molecular landscape and therapeutic avenues.
ARTICLE | doi:10.20944/preprints202310.0215.v1
Subject: Engineering, Electrical And Electronic Engineering Keywords: PMUT; ultrasound; MEMS; finite difference method; characterization; lumped-element; vibrometry.
Online: 4 October 2023 (09:06:16 CEST)
A complete model was developed to simulate the behavior of a circular clamped axisymmetric fluid-coupled Piezoelectric Micromachined Ultrasonic Transducer (PMUT). Combining Finite Difference and Boundary Element Matrix (FD-BEM), this model is based on the discretization of the partial differential equation used to translate the mechanical behavior of a PMUT. In the model, both the axial and the transverse displacements are preserved in the equation of motion and used to properly define the neutral line position. To introduce fluid coupling, a Green’s function dedicated to axisymmetric circular radiating sources is employed. The resolution of the behavioral equations is used to establish the equivalent electroacoustic circuit of a PMUT that preserves the average particular velocity, the mechanical power, and the acoustic power. Particular consideration is given to verifying the validity of certain assumptions that are usually made across various steps of previously reported analytical models. In this framework, the advantages of the membrane discretization performed in the FD-BEM model are highlighted through accurate simulations of the first vibration mode and especially the cutoff frequency that many other models do not predict. This high cutoff frequency corresponds to cases where the spatial average velocity of the plate is null and is of great importance for PMUT design because it defines the upper limit above which the device is considered to be mechanically blocked. These modeling results are compared with electrical and dynamic membrane displacement measurements of AlN-based PMUTs in air and fluid. This complete PMUT model using the FD-BEM approach is shown to be very efficient in terms of computation time and accuracy.
ARTICLE | doi:10.20944/preprints202309.1829.v1
Subject: Biology And Life Sciences, Horticulture Keywords: yellow sapote; tree selection; viviparity; leaf characterization; early seed germination
Online: 27 September 2023 (05:13:32 CEST)
Canistel (Pouteria campechiana (Kunth) Baehni) (yellow sapote, canistel). Originally from Mexico, the fruit is edible, and the tree is used as an ornamental and medicinal plant. Descriptive studies were carried out with the objective of morphologically characterizing the fruits and leaves of trees located in different regions of Mexico to select outstanding specimens and propose their massive reproduction. The trees were selected in three zones. In zone 2 from flower anthesis to harvest 11 months, fruits with 3 seeds, greater weight (180 to 330 g) and quantity of pulp (198.88 g), subglobose shape, total soluble solids 33 %. The fruits of zone 1 at harvest 8 months and zone 3 took 9 months to be harvested, in the rest of the characteristics evaluated were exceeded by the fruits of zone 2. To characterize the canistel (P. campechiana) leaf and identify accessions or cultivars, the three main variables, according to the principal component analysis were: leaf area, perimeter, and minor diameter. The three zones where canistel fruits and leaves were characterized are important and can be recommended for propagation in zones with favorable climatic conditions for fruiting in tropical and subtropical regions of Mexico.
ARTICLE | doi:10.20944/preprints202309.1302.v1
Subject: Biology And Life Sciences, Plant Sciences Keywords: Bacterial blight; Xanthomonas oryzae pv. oryzae; molecular characterization; resistance genes
Online: 19 September 2023 (11:00:55 CEST)
In Benin, Xanthomonas oryzae pv. oryzae (Xoo) causing bacterial blight (BLB) was first described in 2013 on wild rice Oryza longistaminata. No studies have been conducted on Beninese Xoo strains and resistant rice varieties. The aim of this study is to check whether Xoo has already spread to cultivated varieties and to screen some rice accessions for the main resistance genes detection. To achieve this aim, rice leaves showing typical BLB symptoms were collected from various rice fields in Benin and analyzed by PCR to identify Xoo-specific sequences. In addition, seventy-five rice accessions were examined to identify Xoo resistance genes. The results showed that Xanthomonas oryzae (Xo) had been identified in Banikouara and Malanville. In addition, Sphingomonas sp was detected in several rice fields. A Xo-Sphingomonas Sp co-infection was also noted. 47 of 75 rice accessions examined (62.66%) carried Xoo resistance genes with 3 (4%) and 40 (53.33%) of xa5 and Xa21 respectively. None of the accessions had neither Xa7 nor Xa13 resistance genes. Three accessions had both xa5 and Xa21 genes. In addition, the rice isogenic lines IRBB60 and IRBB21used as positive controls, were found to be susceptible. These results indicate that Xo has evolved from a wild rice to cultivated varieties in northern Benin. Consequently, a varietal improvement program must be implemented with varieties having resistance genes to prevent a BLB pandemic in Benin.
ARTICLE | doi:10.20944/preprints202309.0647.v1
Subject: Biology And Life Sciences, Biology And Biotechnology Keywords: biofilm characterization; cyanobacteria; phototrophic biofilms; carrier; loofah sponge; Luffa cylindrica
Online: 11 September 2023 (09:31:06 CEST)
Cyanobacteria are promising organisms for the sustainable production of various biotechnologi-cal interesting products. Due to their energy production via photosynthesis, the cultivation of cyanobacteria expands the CO2 cycle. Most cyanobacteria form biofilms on surfaces in their natu-ral environment by surrounding the cells with a self-produced matrix of extracellular polymeric substances (EPS) that hold the cells together. These special growth properties need special reac-tors for cultivation. By immobilizing cyanobacteria on carriers, systems currently established in industry could also be used for biofilm formers. Various artificial carriers for immobilized growth of cyanobacteria and microalgae have already been described in the literature. However, the use of waste materials or natural biodegradable carriers would be more sustainable and is, therefore, the focus of this study. Dried Luffa cylindrica, zeolite, and corn stalks were investigated for their use as carriers for cyanobacteria. L. cylindrica was shown to be an excellent natural carrier for (i) Anabaena cylindrica (ii) Nostoc muscorum 1453-12a, and (III) Nostoc muscorum 1453-12b. Higher or at least similar growth rates were achieved when cyanobacteria were cultivated with L. cylindrica compared to submerged cultivation. Additionally, the production of EPS and C-phycocyanin was increased at least 1.4-fold in all strains by culturing on L. cylindrica. The improved growth could be explained on the one hand by the high surface area of L. cylindrica and its properties, and on the other hand by the release of growth-promoting nutrients from L. cylindrica to the medium.
ARTICLE | doi:10.20944/preprints202306.0615.v1
Subject: Engineering, Mining And Mineral Processing Keywords: marble; small-scale mining; blast impact; fragments size characterization; WipFrag,
Online: 8 June 2023 (09:44:49 CEST)
Blast charge initiation procedures have a significant impact on both mining safety and production rates. In this study, the inventory benefit of an electric initiation system was investigated to assess its influence on both fragmentation and blast-induced damages. The Wipfrag software's was used to examine the size distribution and productivity of 12 small-scale blasts initiated by both non-electric and electric detonators. All blast rounds was initiated with plain type of electric and NONEL detonators. The average burden, spacing, stemming length, and charge weight were, respectively, 0.85 m, 1.10 m, 0.66m, and 1.1kg. The results showed that the mesh through which 80% of the blast fragments will pass for the electric blast is smaller than the mesh through which the material products from the NONEL blast will pass. The results also demonstrate that the generated blast-induced ground vibration (PPV) from all blast rounds for electric blast varies from 0.4–1.2 mm/s and 80–105dB, while that for non-electric blast ranges from 0.05–0.2mm/s and 72–95dB. As a result, the electric blast initiation technique was found to produce good fragmentation, with a higher percentage of optimum fragment sizes on spec than non-electrically initiated blasts.
ARTICLE | doi:10.20944/preprints202306.0249.v1
Subject: Chemistry And Materials Science, Applied Chemistry Keywords: Oxolinic acid; Metal-based complex; Spectroscopy; Microscopic characterization; Antimicrobial activity.
Online: 5 June 2023 (07:09:44 CEST)
The chemical reaction between the quinolone antibiotic oxolinic acid (OA) and Fe(III), Zn(II), Ca(II), and Mg(II) ions results in the formation of metal-based complexes with the following formulas: [Fe(OA)(H2O)2Cl2]2H2O, [Zn(OA)(H2O)Cl]2H2O, [Ca(OA)(H2O)Cl], and [Mg(OA)(H2O)Cl]. We used analytical (C, N, H, Cl, metal analysis) and spectral (FT-IR, 1H NMR, UV-visible) data to structurally characterize the synthesized metal-based complexes of the OA molecule. We found that the OA molecule utilizes the two oxygen atoms of the carboxylate group and the pyridone C=O group to bind the investigated metal ions. The morphological properties of the synthesized OA complexes were assessed using X-ray powder diffractometry (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). The biological properties, specifically antibacterial and antifungal activity, of the synthesized complexes were evaluated in vitro using the Kirby-Bauer disc diffusion protocol with five bacterial and three fungal strains. The complex containing Ca(II) ions exhibited remarkable antibacterial and antifungal activity against all tested microbial strains, surpassing or equaling the potency of the standard drugs (streptomycin for antibacterial assays and ketoconazole for antifungal assays).
REVIEW | doi:10.20944/preprints202305.1796.v1
Subject: Chemistry And Materials Science, Food Chemistry Keywords: proso millet starch; extraction; characterization; modification; in vitro digestibility; application
Online: 25 May 2023 (10:17:40 CEST)
Proso millet starch (PMS) as an unconventional and underutilized cereal starch is becoming increasingly popular worldwide due to its health-promoting properties. This review summarizes research progress in the isolation, characterization, modification, and applications of PMS. PMS can be isolated from proso millet grains by acidic, alkaline, or enzymatic extraction. PMS exhibits typical A-type polymorphic diffraction patterns and shows polygonal and spherical granular structures with a granule size of 0.3-17 µm. PMS is modified by chemical, physical, and biological methods. The native and modified PMS are analyzed for swelling power, solubility, pasting properties, thermal properties, retrogradation, freeze-thaw stability, and in vitro digestibility. The improved physicochemical, structural, and functional properties and digestibility of modified PMS are discussed in terms of their suitability for specific applications. The potential applications of native and modified PMS in food and non-food products are presented. Future prospects for research and commercial use of PMS in the food industry are also highlighted.
ARTICLE | doi:10.20944/preprints202212.0433.v1
Subject: Physical Sciences, Quantum Science And Technology Keywords: Optimal control; supervised learning; system characterization; two-level quantum systems
Online: 23 December 2022 (01:44:57 CET)
We investigate the extent to which a two-level quantum system subjected to an external time-dependent drive can be characterized by supervised learning. We apply this approach to the case of bang-bang control and the estimation of the offset and the final distance to a given target state. The estimate is global in the sense that no a priori knowledge is required on the parameters to be determined. Different neural network algorithms are tested on a series of data sets. We point out the limits of the estimation procedure with respect to the properties of the mapping to be interpolated. We discuss the physical relevance of the different results.
ARTICLE | doi:10.20944/preprints202211.0175.v1
Subject: Medicine And Pharmacology, Orthopedics And Sports Medicine Keywords: laser therapy; musculoskeletal system; tissue penetration depth; laser beam characterization
Online: 9 November 2022 (10:24:26 CET)
There is increasing interest in the application of near-infrared (NIR) laser light for the treatment of various musculoskeletal disorders. The present study thoroughly examined the physical characteristics of laser beams from two different laser therapy devices that are commercially available for the treatment of musculoskeletal disorders. Then, these laser beams were used to measure the penetration depth in various biological tissues from different animal species. The key result of the present study was the finding that for all investigated tissues, most of the initial light energy was lost in the first one to two millimeters, more than 90% of the light energy was absorbed within the first ten millimeters, and there was hardly any light energy left after 15 – 20 mm of tissue. Furthermore, the investigated laser therapy devices fundamentally differed in several laser beam parameters that can have an influence on how light is transmitted through tissue. Overall, the present study showed that a laser therapy device that is supposed to reach deep layers of tissue for treatments of musculoskeletal disorders should operate with a wavelength between 800 nm and 905 nm, a top-hat beam profile, and it should emit very short pulses with a large peak power.
COMMUNICATION | doi:10.20944/preprints202201.0462.v1
Subject: Biology And Life Sciences, Animal Science, Veterinary Science And Zoology Keywords: roe deer; Tick-Borne Encephalitis; neurologic disease; pathology; genetic characterization
Online: 31 January 2022 (13:21:18 CET)
Tick borne encephalitis virus (TBEV) is the causative agent of Tick borne encephalitis in humans, a severe zoonosis occurring in the Paleartic region mainly transmitted through ticks belonging to the genus Ixodes. In Italy, TBEV is restricted to few foci in the north-eastern part of the country. This report describes for the first time a case of clinical TBE in a roe deer, occurred in the Belluno province, Veneto region, an area highly endemic for the presence of the virus. The affected roe deer showed ataxia, staggering movements, muscle tremors and persistent teeth grinding causing hypersalivation. At necropsy, the macroscopic picture was inconclusive. RNA of TBEV was detected by real-time RT-PCR. Phylogenetic analysis revealed a close relationship to TBEV of the European subtype, and 100% similarity with a virus from the bordering Trento Province. The histological examination of the midbrain confirmed the viral etiology and specific immunofluorescence indicated the presence of a Flavivirus infection and characterized the pattern of infection in the neurons. This report underlines for the first time the occurrence of clinical encephalitic manifestations due to TBEV in a roe deer, thussuggesting to include this pathogen in the frame of differential diagnosis in this species.
ARTICLE | doi:10.20944/preprints202105.0728.v1
Subject: Biology And Life Sciences, Biochemistry And Molecular Biology Keywords: theratyping; cystic fibrosis; functional characterization; personalized medicine; CFTR; rare mutation
Online: 31 May 2021 (10:11:41 CEST)
The new CFTR modulator combination, elexacaftor/tezacaftor/ivacaftor (Trikafta) was approved by the FDA in October 2019 for treatment of Cystic Fibrosis in patients 12 years of age or older who have at least one F508del mutation in one allele and a minimal-function or another F508del mutation in the other allele. However, there is a group of patients, in addition to those with rare mutations, in which despite the presence of a F508del in one allele, it was not possible to identify any mutation in the other allele. Today these patients are excluded from treatment with Trikafta. In Italy CF patients carrying F508del/unknown represent about 3% (156 patients) of the overall Italian CF patients. In this paper we show that the Trikafta treatment of nasal epithelial cells, derived from F508del/Unknown patients, results in a significant rescue of CFTR activity. Based on our findings, we think that the F508del/Unknown patients considered in this study could obtain clinical benefits from Trikafta treatment, and we strongly suggest their eligibility for this type of treatment.This study, adding further evidence in the literature, once again confirms the validity of functional studies on nasal cells in the cystic fibrosis theratyping and personalized medicine.
ARTICLE | doi:10.20944/preprints202103.0660.v1
Subject: Chemistry And Materials Science, Analytical Chemistry Keywords: ZnO; Room Temperature Synthesis; XRD Characterization UV-Vis reflectance spectroscopy
Online: 26 March 2021 (11:38:42 CET)
ZnO has many technological applications which largely depend on its properties that can be tuned by controlled synthesis. Ideally, the most convenient ZnO synthesis is carried out at room temperature in aqueous solvent. However, the correct temperature values are often loosely defined. In the current paper we performed synthesis of ZnO in aqueous solvent, by varying reaction and drying temperature by 10°C steps and monitored the synthesis products primarily by XRD. We found out that a simple direct synthesis of ZnO, without additional surfactant, pumping of freezing, required both a reaction (TP) and a drying (TD) temperature of 40°C. Higher temperatures also afford ZnO, but lowering any of the TP or TD below the threshold value results either in the achievement of Zn(OH)2 or in a mixture of Zn(OH)2/ZnO. A more detailed Rietveld analysis of the ZnO samples reveals a density variation with the synthesis temperature and an increase of the nanoparticles average size also verified by SEM images. The optical properties of ZnO obtained by UV-Vis reflectance spectroscopy indicate a red shift of the band gap by ~0.1 eV.
ARTICLE | doi:10.20944/preprints202101.0614.v1
Subject: Biology And Life Sciences, Anatomy And Physiology Keywords: Durum wheat; Tunisian landraces; genetic diversity; population structure; phenotypic characterization
Online: 29 January 2021 (11:53:26 CET)
During the 1970s, Tunisian durum wheat landraces were replaced progressively by modern cultivars. These landraces are nowadays maintained by smallholder farmers in some ecological niches and are threatened gradually by extinction resulting on the narrowing of the genetic diversity. This study aims to investigate patterns of phenotypic variability using twelve quantitative traits in a panel of 189 durum wheat landraces and seven checks, based on farmer’s population name attribution and genetic structure. Our results showed high phenotypic variability among and within landraces and checks for the majority of the studied traits. The principal components analysis showed similar grouping using farmers name attribution and genetic structure using K = 6, which confirmed the identification of a new gene pool in the oases of Tunisia, represented by the sub-population Jenah Zarzoura and the robustness and high relationships between phenotypic and genome-wide genetic structure using DArTseq method. These findings will enhance the conservation efforts of these landraces and their use in breeding efforts at national and international levels to adapt to dry conditions.
ARTICLE | doi:10.20944/preprints202010.0472.v1
Subject: Biology And Life Sciences, Anatomy And Physiology Keywords: BLB Resistance; Xa genes; Xoo; Molecular characterization; Rice; LRR; S_TKc
Online: 23 October 2020 (09:13:39 CEST)
Globally, rice is utilized as staple food, belongs to the family Poaceae. From the past few decades under variable climate conditions, it greatly affected by the bacterial leaf blight (BLB) disease caused by a bacterium Xanthomonas oryzae pv. oryzae (Xoo). Scientists studied causes of the disease and found more than 61 isolates of Xoo. About 39 Xa genes were noted that cause race specifically resistance either individually or in pairs against Xoo. The canvas on the characterization of these genes is still unrevealed. In this study, amino acid sequences of Xa15, Xa19, Xa20 and Xa21 were mined and used for motif-domain identification, characterization, and comparative analysis. It includes screening of physical and chemical characteristics, sequence comparison to find sequence similarity between them and their phylogenetic comparison with other Xa genes and other species based upon LRR and S_TKc domains to find evolutionary relationship among them. The comparison-based modeling was performed and assessed by different tools to gain better understanding and structural evaluation. The results showed identified domains are specific in function, each domain involved in resistance against biotic and abiotic stresses through regulating different cellular processes. This study also revealed high similarity (>98% sequence identity) between these genes and encode a similar leucine-rich repeat receptor kinase like protein. It will optimize the breeding programs as it will be useful for the selection of effective genes to produce resistance in rice varieties against the specific strains of Xoo that will be more effective against BLB than the other Xa genes.
ARTICLE | doi:10.20944/preprints202006.0219.v1
Subject: Biology And Life Sciences, Biology And Biotechnology Keywords: tetrasubsituted imidazoles; synthesis; cyclocondensation reaction; characterization; antibacterial activity; compound K2
Online: 17 June 2020 (13:18:37 CEST)
A new class of tetrasubstituted imidazole based compounds was synthesized using a multicomponent one-pot synthesis scheme through a cyclo condensation reaction of benzil, aromatic primary amines, aldehydes and ammonium acetate in glacial acetic acid. The synthesized compounds have been analyzed and characterized by melting point, color, conductivity method, CHN analysis, FT-IR, and UV-Visible. The reaction proceeding was examined by TLC after regular intervals of period. To test biological activity, the synthesized compounds have been examined against various bacterial strains. From the analysis of the antibacterial activity of these synthesized compounds demonstrated that all three imidazole compounds have considerable to significant activity against the strains, and compound K2 was found potent comparatively.
ARTICLE | doi:10.20944/preprints202307.0689.v1
Subject: Environmental And Earth Sciences, Waste Management And Disposal Keywords: agricultural utilization; biosolids; characterization; land application; sustainable management; sewage sludge; standardization.
Online: 11 July 2023 (10:20:35 CEST)
One of the issues facing modern society, whatever the socio-economic level of the communities involved, is the development of sustainable strategies in the management of sludge/biosolids. Today, it is imperative to replace solutions aimed at simply “disposing of” with those oriented towards “maximizing recovery benefits”. It is desirable that agricultural use remains the main option in sludge/biosolids management, but to ensure effective and safe agronomic benefits, correctly fulfill the legal requirements, and build stakeholder and public confidence, rigorous and sustainable procedures need to be estab-lished. The development of realistic and enforceable regulation is crucial as it represents the right bal-ance between the different aspects of a coordinated and effective management. Furthermore, it is to recognize that regulation needs to be supported by standardized character-ization procedures and guidelines of good practices, because well-defined procedures allow le-gal requirements to be correctly and uniformly met, thus ensuring reliable comparison of re-sults obtained under different conditions. In this article, main aspects to consider for a sustainable application of this management practice are discussed, together with the parameters that need to be evaluated for the characterization of sludge/biosolids, according to the various aspects related to the agricultural use.
ARTICLE | doi:10.20944/preprints202306.1978.v1
Subject: Engineering, Aerospace Engineering Keywords: UAV; additive manufacturing; material experimental characterization; multirotor UAV airframe; CAx; CAD
Online: 28 June 2023 (09:34:46 CEST)
In this paper, the characterization of 3D printed materials that are considered in the design of multirotor unmanned aerial vehicles (UAVs) for specialised purposes was carried out. The multirotor UAV system is briefly described, primarily from the aspect of system dynamics, considering that the airframe parts connect the UAV components, including the propulsion configuration, into a functional assembly. Three additive manufacturing (AM) technologies were discussed, and a brief overview was given of selective laser sintering (SLS), fused deposition modeling (FDM), and continuous fiber fabrication (CFF). Using hardware and related software, 12 series of specimens were produced which were experimentally tested utilizing a quasi-static uniaxial tensile test. The results of the experimental tests are given graphically with displacement-force characteristics. In this work, the focus is on CFF technology and the testing of materials that will be used in the production of mechanically loaded airframe parts of multirotor UAVs. Furthermore, an overview was given in such a way that the specimens were grouped, and the mean values of the maximum stress were presented, so that the tested materials could be more easily compared with conventional materials, such as aluminum alloys.
REVIEW | doi:10.20944/preprints202305.0300.v1
Subject: Chemistry And Materials Science, Biomaterials Keywords: Chitosan; Hydrogel; biomedical application; stimuli-responsive hydrogels; synthesis methods; characterization methods
Online: 5 May 2023 (04:50:52 CEST)
The prospective applications of chitosan-based hydrogels (CBHs), a category of biocompatible and biodegradable materials, in biomedical disciplines such as tissue engineering, wound healing, drug delivery, and biosensing have garnered great interest. The synthesis and characterization processes used to create CBHs play a significant role in determining their characteristics and effectiveness. The processing procedure could be tailored to obtain specific features like porosity, swelling, mechanical strength, degradation rate, and bioactivity, affecting the properties of CBHs to a great extent. Additionally, characterization methods aid in gaining access to the microstructures and properties of CBHs. Especially, this review provides a comprehensive assessment of the state-of-the-art with a focus on the affiliation between particular properties and application domains. The main obstacles and prospects for the future of CBH development for biomedical applications are also covered in the review.
ARTICLE | doi:10.20944/preprints202206.0416.v1
Subject: Physical Sciences, Condensed Matter Physics Keywords: Thin films; BiFeO3/VO2; Solid-solid interface; Surface characterization; Electrical property
Online: 30 June 2022 (06:16:25 CEST)
Thin films of BiFeO3 (BFO), VO2 and BFO/VO2 were grown on SrTiO3(100) and Al2O3(0001) monocrystalline substrates using the RF and DC sputtering techniques. The surface of the films was characterized by profilometry, AFM, and XPS. The heterostructures have roughnesses between 0.2 and 16 nm and a grain size between 20 nm and 67 nm. XPS measurements show a higher proportion of the V4+ and Bi3+ oxides. In the Fe region, a higher proportion of Fe3+ is shown in the films. The homogeneous ordering, low roughnesses, and the oxidation states on the obtained surface show a good coupling in these films. The I-V curves show ohmic behavior at room temperature and change with increasing temperature. The effect of coupling these materials in a thin film shows the appearance of hysteresis cycles I-V and R-T, typical of materials with high potential in applications such as resistive memories and solar cells.
REVIEW | doi:10.20944/preprints202205.0113.v1
Subject: Physical Sciences, Condensed Matter Physics Keywords: electron beam sensitive materials; electron microscopic characterization; low dose; iDPC-STEM
Online: 9 May 2022 (09:56:01 CEST)
The main aspects of material research: material synthesis, material structure, and material properties, are interrelated. Acquiring atomic structure information of electron beam sensitive materials by electron microscope, such as porous zeolites, organic-inorganic hybrid perovskites, metal-organic frameworks, is an important and challenging task. The difficulties in characterization of the structures will inevitably limit the optimization of their synthesis methods and further improve their performance. The emergence of integrated differential phase contrast scanning transmission electron microscopy (iDPC-STEM), a STEM characterization technique capable of obtaining images with high signal-to-noise ratio under lower doses, has made great breakthroughs in the atomic structure characterization of these materials. This article reviews the developments and applications of iDPC-STEM in electron beam sensitive materials, and provides an outlook on its capabilities and development.
ARTICLE | doi:10.20944/preprints202202.0166.v1
Subject: Biology And Life Sciences, Immunology And Microbiology Keywords: microbiological characterization; safety; VanZ; isolation; vancomycin resistant gene; genome; bee; honey
Online: 11 February 2022 (21:17:45 CET)
Bifidobacteria have long been recognized as bacteria with probiotic and therapeutic features. The aim of this work is to characterize the Bifidobacterium asteroides BA15 and BA17 strains, isolated from honeybee gut. An in-depth assessment was carried out on safety properties (antibiotic resistance profiling, β-haemolytic, DNAse and gelatinase activities and virulence factor presence) and other properties (antimicrobial activity, auto-aggregation, co-aggregation and hydrophobicity). Based on phenotypic and genotypic characterization, both strains satisfied all the safety requirements. More specifically, genome analysis showed the absence of genes encoding for glycopeptide (vanA, vanB, vanC-1, vanC-2, vanD, vanE, vanG), resistance to tetracycline (tet-M, tet-L and tetO), and virulence genes (asa1, gelE, cylA, esp, hyl).
ARTICLE | doi:10.20944/preprints202112.0144.v1
Subject: Medicine And Pharmacology, Pediatrics, Perinatology And Child Health Keywords: 21-hydroxylase deficiency; congenital adrenal hyperplasia; CYP21A2; functional characterization; Cytochrome P450
Online: 9 December 2021 (08:34:16 CET)
Deficiency of Cytochrome P450 Steroid 21-hydroxylase (CYP21A2) represents 90% of cases in congenital adrenal hyperplasia (CAH), an autosomal recessive disease caused by defects in cortisol biosynthesis. Computational prediction along with functional studies are often the only way to classify variants to understand the links to disease-causing effects. Here we investigated the pathogenicity of uncharacterized variants in the CYP21A2 gene reported in the Brazilian and Portuguese populations. Physicochemical alterations, residue conservation, and effect on protein structure were accessed by computational analysis. The enzymatic performance was obtained by functional assay with the wild-type and mutant CYP21A2 proteins expressed in HEK293 cells. Computational analysis showed that p.W202R, p.E352V, and p.R484L have severely impaired the protein structure, while p.P35L, p.L199P, and p.P433L have moderate effects. The p.W202R, p.E352V, p.P433L, and p.R484L variants showed residual 21OH activity consistent with the simple virilizing phenotype. The p.P35L and p.L199P variants showed partial 21OH efficiency associated with the non-classical phenotype. Additionally, p.W202R, p.E352V and p.R484L also modified the protein expression level. We have determined how the selected CYP21A2 gene mutations affect the 21OH activity through structural and activity alteration contributing to the future diagnosis and management of 21OH deficiency.
ARTICLE | doi:10.20944/preprints202107.0427.v1
Subject: Environmental And Earth Sciences, Waste Management And Disposal Keywords: Solid waste management; LED lamp; characterization protocol; recycling; LED waste management
Online: 20 July 2021 (09:25:18 CEST)
Solid-state lighting has been replacing conventional lighting in the market, raising concerns for implementing an efficient end-of-life management system. Since LED waste streams have not been quite dominant, characterization studies (product-level characteristics, component-wise information, bill of materials, diversity, and differences) are inconsistent and having substantial gaps. This study investigates the end-of-life LED lamp literature, focusing on the bill-of-materials, and reveals that the characterization procedure suffers from a severe lack of sample representativeness. Consequently, characterization results are widely varied and not generalizable. Moreover, most of the studies did not inform and document the detailed sample characteristics, precluding the possibility of identifying reasons for variation. Combining available information from the recent studies, we present a mass distribution at the component level, exemplifying the prospect for meeting EU regulatory limit and the need for more insight at the lamp and component level. To fill the disconnection between lamp level characteristics and component and material content, we propose a characterization protocol that carefully documents lamp, component, and material level information by establishing a lamp-component–material composition nexus. The protocol may help researchers, policymakers, and industrial stakeholders conduct a systematic characterization, analyze complexities and prepare for a sustainable solution.
ARTICLE | doi:10.20944/preprints202105.0394.v1
Subject: Biology And Life Sciences, Biophysics Keywords: Modularity; Protein-to-protein interaction networks; Spectral characterization; Tree of life
Online: 17 May 2021 (16:56:57 CEST)
Modularity and organizational hierarchy are important concepts in understanding the structure and evolution of interactions in complex biological systems. In this work, we introduce and use a spectral characterization measure (Spectral Entropy) to quantify modularity in protein-to-protein interaction (PPI) networks in species across the tree of life. We evaluated the relation between the size of a PPI network and its (Spectral Entropy-based) modularity, and found a sigmoidal response between the two. We also found significant differences in the distribution of Spectral Entropy values among the three domains of life (Bacteria, Archaea, Eukaryotes). To explore further correlations with biological traits, we focused solely on bacterial PPI networks, which are the most numerous among the three domains and had associated trait metadata, and investigated how modularity impacts or is impacted by growth, aerobicity, selection and location on the tree of life. We found no relation between maximal growth rate and Spectral Entropy, but a strong dependence between G-C content (a proxy for selection) and Spectral Entropy. We also discovered that Spectral Entropy is negatively affected by phylogenetic placement (evolutionary distance from the last universal common ancestor). The general nature of the Spectral Entropy measure of hierarchical modularity in networks suggests that it will be useful in other settings where structural properties of real-world networks are being compared.
ARTICLE | doi:10.20944/preprints202102.0080.v1
Subject: Chemistry And Materials Science, Analytical Chemistry Keywords: Chemical characterization; New psychoactive substances; Synthetic cathinones; FTIR; GC-MS; NMR
Online: 2 February 2021 (09:44:23 CET)
The innovation of the new psychoactive substances (NPS) market requires the rapid identification of new substances that can be a risk to public health, in order to reduce the damage due to their use. Twelve seized products suspected to contain illicit substances were analyzed by attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), gas chromatography coupled to mass spectrometry (GC-MS), and nuclear magnetic resonance spectroscopy (NMR). Synthetic cathinones (SCat) were found in all products, either as a single component or in mixtures. Infrared spectra of all products were consistent with the molecular structure of SCat, showing an intense absorption band at 1700–1674 cm‐1, corresponding to the carbonyl stretching, a medium/strong peak at 1605-1580 cm-1, indicating stretching vibrations in the aromatic ring (C=C) and bands with relative low intensity at frequencies near 2700–2400 cm-1, corresponding to an amine salt. It was possible to identify a total of eight cathinone derivatives by GC-MS and NMR analysis: 4’-methyl-α-pyrrolidinohexanophenone (MPHP), α-pyrrolidinohexanophenone (α-PHP), 3-fluoromethcathinone (3-FMC), methedrone, methylone, buphedrone, N-ethylcathinone, and pentedrone. Among the adulterants found in these samples, caffeine was the most frequently detected substance, followed by ethylphenidate. These results highlight the prevalence of SCat in seized materials of the Portuguese market. Reference standards are usually required for confirmation, but when reference materials are not available, the combination of complementary techniques is fundamental for a rapid and an unequivocal identification of such substances.
ARTICLE | doi:10.20944/preprints202009.0267.v3
Subject: Engineering, Automotive Engineering Keywords: mechanical characterization; foams; ultrafiltration membrane; finite element method; non-linear deformations
Online: 15 October 2020 (16:48:45 CEST)
To investigate the effect of Polyvinylpyrrolidone (PVP) addition and consequently porosity, two different sets of membranes are manufactured, since PVP is a widely used poring agent which has an impact on the mechanical properties of the membrane material. The first set (PAN 1) includes PAN and the necessary solvent while the second set (PAN 2) is made of PAN and PVP. These membranes are put through several characterisation processes including tensile testing. The obtained data are used to model the static behaviour of the membranes with different geometries, but similar loading and boundary conditions that represent their operating conditions. This modelling process is undertaken by using finite element method. The main idea is to investigate how geometry affects the load-carrying capacity of the membranes. Alongside membrane modelling, their materials are modelled with representative elements with hexagonal and rectangular pore arrays (RE) to understand the impact of porosity on the mechanical properties. Exploring the results, the best geometry is found as the elliptic membrane with the aspect ratio 4 and the better RE as the hexagonal array which can predict the elastic properties with an approximate error of 12%.
ARTICLE | doi:10.20944/preprints202009.0447.v1
Subject: Chemistry And Materials Science, Nanotechnology Keywords: nano- and micro-sized TiO2; photocatalytic efficiency; photoelectrochemical characterization; environmental remediation
Online: 19 September 2020 (05:11:43 CEST)
The size of TiO2 (either nanometric or micrometric) can significantly affect both its photocatalytic and photoelectrochemical properties, thus altering the photooxidation of organic pollutants in air or water. The purpose of this work is to give an account of the photoelectrochemical and photocatalytic features of some nano- and micro-sized TiO2 commercial powders towards a model reaction, the photooxidation of acetone. Cyclic voltammograms (CV) of TiO2 particulated electrodes under UV illumination experiments were carried out in either saturated O2 or N2 solutions for a direct correlation with the photocatalytic process. In addition, the effect of different reaction conditions on the photocatalytic efficiency under UV light in both aqueous and gaseous phases was also investigated. CV curves with the addition of acetone under UV light showed a negative shift of the photocurrent onset, confirming the efficient transfer of photoproduced reactive oxygen species (ROSs), e.g., hydroxyl radicals, or holes to acetone molecules. The photocatalytic experiments showed that the two nano-sized samples exhibit the best photocatalytic performance. The different photoactivity of the micro-sized samples is probably attributed to their morphological differences, affecting both the amount and distribution of free ROSs involved in the photooxidation reaction.
ARTICLE | doi:10.20944/preprints202311.1467.v1
Subject: Environmental And Earth Sciences, Pollution Keywords: microplastics, polyethylene, polystyrene, polypropylene, characterization, identification, FT-IR, Raman, Somesul Mic River
Online: 23 November 2023 (04:54:42 CET)
Microplastics (MPs) pollution has become a persisting problem over the last decades and a critical issue for environmental protection and human health. In this context any scientific data able to reveal the MPs presence and to improve the characterization and identification in different systems is valuable. The aim of this paper was to assess available techniques for determining MPs in real freshwater samples and subsequently to highlight the occurrence and type of MPs in the study case area (Somesul Mic River). The specific objectives of the study were: i) MPs separation and visual characterization; ii) microscopic analyses and morphological characterization of MPs; iii) Raman and FT-IR spectroscopic identification of MPs. MPs sampling was performed from the fresh water and sediment using planktonic nets and sieves with different mesh sizes (20 to 500µm). After digestion with hydrogen peroxide, the MPs characterization was performed using both classical microscopic techniques as well as scanning electron microscopy (SEM). For the MPs identification, Raman and FT-IR spectrometry techniques were used. Large (1-5 mm) and small (1 µm to 1 mm) MPs were observed in the shape of fibers, fragments, foam, foils and spheres in various colors (red, green, blue, purple, pink, white, black, transparent, opaque). Polymers were identified related to scientific literature and reference spectra. The presence of polyethylene (PE), polypropylene (PP) and polystyrene (PS) was registered for all sampling point. The MPs laboratory investigations have raised some issues regarding the identification of MPs particles with the size smaller than 500µm, being characterized especially under microscope. Small MPs particle dispersed on cellulose filter were identified using micro-Raman spectroscopy highlighting the same type of polymers. The results showed that both spectrometric methods Raman or FT-IR confirm the identification of the same type of polymers. No differences were registered between the sampling points due to the widespread presence of MPs. The sediments samples presented a greater abundance compared to the water samples. Overall, it is necessary to continue the optimization of the MPs separation protocol and identification according to the complexity of samples, mainly due to the limitation and lack of spectral databases.
ARTICLE | doi:10.20944/preprints202310.1205.v1
Subject: Biology And Life Sciences, Food Science And Technology Keywords: grape pomace extract; phenolic compounds; encapsulation; drying; microbeads characterization; release in vitro
Online: 19 October 2023 (03:56:48 CEST)
Grape pomace is a byproduct of wineries and sustainable source of bioactive phenolic compounds. Encapsulation of phenolics with a well-chosen coating may be a promising means of delivering them to the intestine, where they can then be absorbed and exert their health-promoting properties. Ionic gelation of grape pomace extract with natural coatings (sodium alginate and its combination with maltodextrins, gelatin, chitosan, tragacanth gum, and gum arabic) was performed, and the resulting hydrogel microbeads were then air-, vacuum-, or freeze-dried to prevent their spoilage. The physicochemical characterization (size, shape, texture, and morphology) of the microbeads and the in vitro release of phenols from microbeads were studied and a good relationship between them was established. Freeze-dried microbeads showed the highest cumulative release of phenols as in the intestinal phase (23.31 – 43.27 mgGAE/gMB), followed by vacuum-dried (23.31 - 35.41 mgGAE/gMB) and air-dried (22.74 – 31.38 mgGAE/gMB), while the most suitable release dynamics in the intestinal phase were observed for alginate-based microbeads combined with gelatin (58.4 %), gum arabic (34 %) and 1.5 % w/v chitosan (15.3 %). The results highlight the importance of developing encapsulated formulations containing a natural source of bioactive compounds that can be used in various functional foods and pharmaceutical products.
ARTICLE | doi:10.20944/preprints202307.1313.v1
Subject: Biology And Life Sciences, Food Science And Technology Keywords: Citrus by-products; Pectin extraction; Optimization; Characterization; Response surface methodology; technological properties
Online: 19 July 2023 (09:54:28 CEST)
Citrus peels are considered as a rich source of valuable biomolecules like pectin as polymer of polysaccharide acid. In this study, response surface methodology was used to optimize pectin extraction from Citrus clementina peels using citric acid as extraction solvent. The effect of parameters conditioning the extraction process and pectin yield (pH, temperature, extraction time, solid/liquid ratio, and raw material particle size) was investigated using a Box-Behnken design. The quality of the extracted pectin was assessed both chemically (moisture, ash, protein, and sugar content) and functionally (gelling power and emulsifying activity). According to the screening experiment, the factors pH, temperature, and particle size were the main factors influencing the pectin yield. The adjusted mathematical model enabled us to plot response surfaces in order to determine optimal extraction conditions. The highest production yield of pectin (26.6%) was obtained at the optimal conditions of: pH = 1.5; temperature 100 °C and particle size = 0.1 mm for an extraction time of 30min. Compared to the predicted value of 26.6%, the experimental extraction yield was about 21.4% of pectin. Concerning the functional properties, the extracted pectin has a high gelling power of 164°SAG and an emulsifying activity of 38.5%.
ARTICLE | doi:10.20944/preprints202307.0153.v1
Subject: Environmental And Earth Sciences, Environmental Science Keywords: Urban Solid Waste, Gravimetric Characterization, Solubilized Extract, Leachate Extract and Organic Fraction.
Online: 4 July 2023 (10:11:01 CEST)
In this study, the gravimetric characterization and analysis of the solubilized extract of the organic fraction of Urban Household Solid Waste (RSDU) from the municipality of Belém do Pará was carried out in order to obtain the composition of the collected materials and the characteristics of the liquid resulting from the solubilization of these materials . The waste used to carry out this research was collected door-to-door, in which the points and neighborhoods served were determined through the sectorization of these locations and representative statistical sampling. For the sectorization of neighborhoods, family income values were considered as the main parameter. After collecting the solid waste, the material was sent to the facilities of the Federal University of Pará (FUPa), where the waste was classified into paper, cardboard, tetrapak, rigid plastic, soft plastic, metals, glass, organic matter, waste toilets, fabrics and others. The organic fraction of solid waste was separated and sent to the drying, crushing and packaging processes. Subsequently, the solubilized extract of the organic fraction of solid waste was obtained, following the methodology recommended by NBR standard nº 10.006/2004, of the Brazilian Association of Technical Standards and the values obtained were compared with Ordinance GM/MS nº 888/2021 and CONAMA Resolution nº 357/2005, in addition to results obtained by other authors. After carrying out the gravimetric characterization, it was possible to obtain the average proportions of 5.09% paper, 3.20% cardboard, 0.94% tetrapak, 3.58% rigid plastic, 9.97% soft plastic, 2.00% metals, 55.57% organic matter, 1.86% glass, 14.26% sanitary waste, 3.23% fabrics and 3.00% other waste. High values of organic residues were found in the gravimetric composition, which can be explained by the collection method used and the high humidity of the organic solid residues. In the analyzes of the solubilized extract, values of Hp (3.69 to 4.92), Turbidity (791 to 1,733 uT), Apparent Color (8,500 to 12,500 uC), True Color (6,000 to 14,000 uC), Total Dissolved Solids (5,330 to 8,040 mg/L), Total Nitrogen (201.80 to 359.90 mg/L), Ammoniacal Nitrogen (161 to 289 mg/L), Nitrate (10 to 40 mg/L), Total Phosphorus (52.30 to 166.80 mg/L) and Chemical Oxygen Demand (28,701 mg/L to 38,608 mg/L), in addition to other measured parameters, in which such information makes it possible to check the similarities of the waste solubilization conditions to that of leachates from landfills, in addition to not being in compliance with environmental and health legislation, demonstrating risks to the local environment and public health.
ARTICLE | doi:10.20944/preprints202306.0607.v1
Subject: Engineering, Other Keywords: Powder-bed fusion; Composite polymers; Discrete element method; Material characterization; Additive manufacturing
Online: 8 June 2023 (08:19:32 CEST)
Polymeric composites such as Poly-ether-ether-ketone (PEEK)/carbon fiber (CF) have been widely utilized due to outstanding performances such as high specific strength and specific modulus. The PEEK/CF components via powder-bed fusion additive manufacturing usually show brittle fracture behaviors induced by their poor interfacial affinity and inner voids. These defects are strongly associated with powder packing quality upon deposition. The particle dynamic model has been widely employed to study the interactions of particle motions. Powder property, bulk material property, and interfacial features of composite powders are key factors in the particle dynamic model. In this work, an efficient and systematic material evaluation is developed for composite powders to investigate their deposition mechanism. The discrete element method is utilized to simulate the dynamic behaviors of PEEK/CF composite powders. The powder properties, bulk material properties, and interfacial features of powders are calibrated and justified by experimental measurement, numerical simulation, and design of experiments. The particle dynamic model can well explain the powder flow behaviors and interactions. It reveals that the addition of short CF particles can assist the flow of PEEK powders and improve the packing quality of the composite powders.
COMMUNICATION | doi:10.20944/preprints202212.0295.v1
Subject: Physical Sciences, Applied Physics Keywords: Metasurface; Materials characterization; Sensing; Microwave sensors; Powders; Materials science; Millimeter wave devices
Online: 16 December 2022 (05:45:54 CET)
A novel technique using a W-band metasurface for the purpose of transmissive fine powder layer sensing is presented. The proposed technique may allow for the detection, identification, and characterization of inhomogeneous ultrafine powder layers which are effectively hundreds of times thinner than the incident wavelengths used to sense them. Such a technique may be useful during personnel screening processes (i.e., at an airport) and in industrial manufacturing environments where early detection and quantization of harmful airborne particulates can be a matter of security or safety. To our knowledge, the requisite science involved in such a novel W-band metasurface sensing technique has not been fully explored.
COMMUNICATION | doi:10.20944/preprints202112.0270.v1
Subject: Biology And Life Sciences, Virology Keywords: Dengue; Dengue virus; cosmopolitan genotype; Senegal; Mauritania; Molecular characterization; Full genome sequencing
Online: 16 December 2021 (12:06:07 CET)
Globally 390 millions of people are at risk of dengue infection; over the past 50 years the virus incidence increased thirty-fold. In Senegal, an unprecedented occurrence of outbreaks and sporadic cases was noticed since 2017. In October 2018 an outbreak of DENV-2 was reported in Rosso area in the north of Senegal at the border with Mauritania. Out of the 187 blood specimen samples collected, 27 were positives by qRT-PCR and 8 were serologically positive for DENV IgM. Serotyping using qRT-PCR reveals that isolates were positive for DENV-2. A subset of DENV-2 positives samples was selected and subjected to full genome sequencing followed by phylogenetic analysis. Analysis of 06 nearly completed genome sequences (n= 6) revealed that isolates belong to the cosmopolitan genotype and are closely related to the Mauritanian strains detected between 2017 and 2018 and those detected in many West African countries such as Burkina Faso or Cote d’Ivoire. Our results suggest a transboundary circulation of the DENV-2 cosmopolitan genotype between Senegal and Mauritania and call for a need of coordinated surveillance of arboviruses between these two countries. Interestingly, high level of homology between West African isolates highlights endemicity and call for a set-up of sub-regional viral genomic surveillance which will lead to a better understanding of viral dynamic, transmission and spread across Africa.
ARTICLE | doi:10.20944/preprints202103.0203.v1
Subject: Biology And Life Sciences, Anatomy And Physiology Keywords: Antimicrobial activity; Characterization; GC-MS analysis; FTIR analysis; Red lily; Secondary metabolites
Online: 5 March 2021 (21:42:00 CET)
The members of the Liliaceae family have been regarded as an excellent source of biologically active compounds. However, the work on antimicrobial potential and characterization of the bioactive fractions of Lilium philadelphicum flower is limited and needs to be explored. The present study reports the antimicrobial potential, anti-inflammatory and anticancer potential of the bioactive fraction extracted from the flower of L. philadelphicum (Red Lily) and characterization of these bioactive compounds. The antimicrobial activity was tested against nine different Gram-positive and Gram-negative bacterial strains. The minimum inhibitory concentration (MIC) values of methanolic extract of L. philadelphicum flower against Acinetobacter bouvetii, Achromobacter xylosoxidans, Bacillus subtilis MTCC 121, Candida albicans MTCC 183, Klebsiella pneumoniae MTCC 3384, and Salmonella typhi MTCC 537 were 25, 50, 12.5, 50, 100 and 50 μg mL-1, respectively. The phytochemical analysis of the extract reveals the presence of phenols, flavonoids, tannins, terpenoids, glycosides, coumarins, and quinones. The cytotoxicity of the partially purified compound against the HepG2 cell line in MTT assay demonstrates up to 90% cell viability with a bioactive compound concentration of 50 μg/ml. However, with the increase in bioactive compound concentration up to 1000 μg/ml results into nearly 80% cell viability, just a minor decline in cell viability suggests the importance of bioactive compounds for suitable therapeutic applications. Spectroscopic studies of the bioactive compound by UV-Visible spectroscopy, FT-Infra Red spectroscopy, Gas Chromatography-Mass Spectrometry (GCMS) as well as its phytochemical analysis suggests the presence of terpenoids moiety, responsible for the antimicrobial property of L. philadelphicum flower.
ARTICLE | doi:10.20944/preprints201806.0128.v1
Subject: Engineering, Chemical Engineering Keywords: biogas purification; coconut shells; biomass valorization; textural characterization; adsorption isotherms; breakthrough curves.
Online: 7 June 2018 (16:27:12 CEST)
Biomass is a widely distributed and renewable source of carbon. The main objective of this work is to produce an activated carbon from coconut shells with suitable characteristics to separate CO2 from biogas. The textural characterization of the adsorbent has been determined. Pure component adsorption isotherms of CO2 and CH4 at 30, 50 and 70 °C have been measured. Moreover, the performance of the produced activated carbon, as potential adsorbent for CO2 capture from a CO2/CH4 gas mixture has been evaluated under dynamic conditions in a purpose-built fixed-bed setup.
ARTICLE | doi:10.20944/preprints202311.1461.v1
Subject: Chemistry And Materials Science, Materials Science And Technology Keywords: double-perovskites; La2FeCrO6 oxides; hydrothermal process; magnetic properties; electrical transport properties; microstructural characterization
Online: 23 November 2023 (09:38:32 CET)
A La2FeCrO6 (LFCO) double perovskite powders were synthesized by hydrothermal method, which crystallized in an orthorhombic (Pnma) structure and exhibited a spherical morphology with average particle size of 900 nm. Fourier transformation infrared spectroscopy confirmed the octahedral coordination of Fe and Cr ions in the powders. XPS spectra revealed dual oxide states of Fe (Fe2+/Fe3+) and Cr (Cr3+/Cr4+) elements, and oxygen element appeared as lattice oxygen and defect oxygen, respectively. The LFCO powders exhibit ferromagnetic behavior at 5 K with saturation magnetization of 0.31 μB/f.u., coercive field of 8.0 kOe, and Curie temperature of 200 K. Griffiths phase appeared in the powders between 200 K and 223 K. The LFCO ceramics displayed a butterfly-like magnetoresistance (MR)-magnetic field (H) curve at 5 K with MR (5 K, 6 T) value of -4.07%. Temperature dependence of resistivity of the LFCO ceramics demonstrated their semiconducting nature. Electrical transport data were fitted by different conduction models. Strong frequency dispersion dielectric behavior was observed in the LFCO ceramics. A dielectric abnormality observed around 260 K, was ascribed to the jumping of electrons trapped in shallow levels created by oxygen vacancies. The dielectric relaxation behavior exhibited by dielectric loss between 160 K and 260 K, was contributed to the singly-ionized oxygen vacancies.
ARTICLE | doi:10.20944/preprints202307.0949.v1
Subject: Environmental And Earth Sciences, Geophysics And Geology Keywords: Fault detection; reservoir characterization; seismic images; deep learning; convolutional neural network; variance attribute
Online: 14 July 2023 (12:41:00 CEST)
Fault detection is an important step for subsurface interpretation and reservoir characterization from 3D seismic images. Due to the numerous and complicated faulting structures of seismic images, manual seismic interpretation is time taking and need intensive work. To overcome this problem, geoscientists are coming up with productive computer-aided techniques for assisting in interpreter science for many years. However, in this paper, we used a pre-trained CNN model to predict faults from the 3D seismic volume of the Poseidon field of Browse Basin, Australia. Basically, this field is highly structured with complex normal faulting throughout the targeted Plover Formations. So, our motivation for this work in this field is to compare machine learning-based fault prediction to user interpreted faults identification with supported by seismic variance attribute. We found very satisfying result using DL with having an improved fault probability volume that outperform variance technology. Therefore, we propose that this workflow could reduce time and able to predict fault quite accurately in any field area.
ARTICLE | doi:10.20944/preprints202306.0206.v1
Subject: Engineering, Electrical And Electronic Engineering Keywords: Gate Resistance; Characterization; de-embedding; radio-frequency MOSFETs (RF MOS- 7 FETs); FinFET
Online: 2 June 2023 (13:39:46 CEST)
The gate resistance is a parasitic element in transistors for RF and millimeter-wave circuits that can negatively impact power gain and noise figure. To develop accurate device models, a reliable measurement methodology is crucial. This article reviews the standard measurement methodology used in the literature and proposes also an additional method, which is evaluated using suitable test structures in a 16nm FinFET process. The advantages and disadvantages of the two approaches are discussed along with their respective application scenarios
ARTICLE | doi:10.20944/preprints202211.0402.v1
Subject: Engineering, Energy And Fuel Technology Keywords: Corn Stover; Hydrothermal carbonization; Hydro-char characterization; Kinetics of major compounds; Structural evolution.
Online: 22 November 2022 (03:13:44 CET)
In this work, the effect of reaction time and biomass-to-H2O ratio on the structural evolution of hydro-char and kinetic of by hydrothermal processing of corn Stover with hot compressed H2O, have been systematically investigated. The experiments were carried out at 250 °C, heating rate of 2.0 °C/min, biomass-to-H2O ratio of 1:10, and reaction times of 60, 120, and 240 minutes, and at 250 °C, 240 minutes, heating rate of 2.0 °C/min, and biomass-to-H2O water ratio of 1:10, 1:15, and 1:20, using a pilot scale stirred tank reactor of 5 gallon. The characterization of solid phase products performed by thermo-gravimetric analysis, scanning electron microscope, energy dispersive X-ray spectroscopy, X-ray diffraction, and elemental analysis (C, N, H, S). The physical-chemistry properties of solid phase analyzed in terms of dry matter (DM), total organic content (TOC), and ash. The yields of solid and gas phases decrease linearly with decreasing biomass-to-H2O ratio, while that of liquid phases increases linearly. For constant biomass-to-H2O ratio, the yields of solid, liquid, and gaseous reaction products varied between 52.97 and 35.82% (wt.), 44.84 and 54.59% (wt.), and 2.19 and 9.58% (wt.), respectively. The yield of solids decreases exponentially by decreasing the reaction time, while the yields of liquid and gas phases increase exponentially. For constant biomass-to-H2O ratio, TG/DTG curves shows that reaction time of 60 minutes was not enough to carbonize corn Stover. For constant reaction time, TG/DTG curves shows that increasing the H2O-to-biomass ratio worse the carbonization of corn Stover. For constant biomass-to-H2O ratio, the SEM images show the main morphological structure of the corn Stover remains practically unchanged, while for constant reaction time, SEM images show that plant microstructure retains part of its original morphology, demonstrating that a decrease on biomass-to-H2O ratio worse the carbonization of corn Stover. For constant biomass-to-H2O ratio, the EDX analysis shows that the carbon content in hydro-char increases with reaction time, while for constant reaction time, the carbon content decreases with increasing biomass-to-H2O ratio. The kinetic of corn Stover degradation was correlated with a pseudo-first order exponential model, exhibiting a root-mean-square error (r2) of 1.000, demonstrating that degradation kinetics of corn Stover with hot compressed H2O, expressed as hydro-char formation, is well described by an exponential decay kinetics.
REVIEW | doi:10.20944/preprints202102.0255.v1
Subject: Medicine And Pharmacology, Immunology And Allergy Keywords: A-to-I RNA editing; ADAR; microRNAs; microRNA targeting; detection; quantification; functional characterization
Online: 10 February 2021 (12:33:42 CET)
RNA editing involves the insertion, deletion or substitution of single nucleotides within a RNA molecule, without altering the DNA sequence. Adenosine to inosine (A-to-I) editing consists of an RNA modification where single adenosines along the RNA sequence are converted into inosines. Such a biochemical transformation is catalyzed by enzymes belonging to the family of adenosine deaminases acting on RNA (ADARs) and occurs either co- or post-transcriptionally. Initially, the A-to-I RNA editing phenomenon was discovered and studied in messenger RNAs (mRNAs), where it can influence RNA splicing and cause the recoding of codon sequences. The employment of more powerful, high-throughput detection methods has recently revealed that A-to-I editing widely occurs in non-coding RNAs, including microRNAs (miRNAs). MiRNAs are a class of small regulatory non-coding RNAs (ncRNAs) acting as translation inhibitors, known to exert relevant roles in controlling cell cycle, proliferation, and cancer development. Indeed, a growing number of recent researches have evidenced the importance of miRNA editing in cancer biology by exploiting various detection and validation methods. Herein, we briefly overview early and currently available A-to-I miRNA editing detection and validation methods and discuss the significance of A-to-I miRNA editing in human cancer.