ARTICLE | doi:10.20944/preprints202105.0358.v1
Subject: Materials Science, Biomaterials Keywords: encapsulation; freeze drying; gelatin; polyphenols; spray drying
Online: 16 May 2021 (19:57:12 CEST)
Freeze drying was compared with spray drying regarding feasibility to process wild thyme drug in order to obtain dry formulations at laboratory scale starting from liquid extracts produced by different extraction methods: maceration, heat-, ultrasound-, and microwave-assisted extractions. Higher powder yield (based on the dry weight prior to extraction) was achieved by freeze than spray drying and lower loss of total polyphenol content (TPC) and total flavonoid content (TFC) due to the drying process. Gelatin as a coating agent (5% w/w) provided better TPC recovery by 70% in case of lyophilization and higher powder yield in case of spray drying by diminishing material deposition on the wall of the drying chamber. The resulting gelatin-free and gelatin-containing powders carried polyphenols in amount ~190 and 53-75 mg gallic acid equivalents GAE/g of powder, respectively. Microwave-assisted extract formulation distinguished from others by higher content of polyphenols, proteins and sugars, higher bulk density and lower solubility. The type of the drying process affected mainly position of the gelatin-derived -OH and amide bands in FTIR spectra. Spray dried formulations compared to freeze dried expressed higher thermal stability as confirmed by differential scanning calorimetry analysis and higher diffusion coefficient; the last feature can be associated with the lower specific surface area of irregularly shaped freeze-dried particles (151-223 µm) compared to small microspheres (~8 µm) in spray-dried powder.
ARTICLE | doi:10.20944/preprints201911.0137.v1
Subject: Life Sciences, Other Keywords: Hibiscus sabdariffa; phenolic compounds; spray-drying; antioxidant capacity
Online: 13 November 2019 (03:15:28 CET)
Aqueous and ethanolic extracts of Hibiscus sabdariffa were spray-drying using maltodextrin (MD) and gum arabic (GA) as carriers agents. An experimental design Taguchi L8 with seven variables was implemented. Physicochemical properties in the encapsulates were evaluated by UV-Vis, XRD, spectroscopy and gravimetric techniques. Treatments with aqueous extracts showed the highest concentration of total soluble polyphenols (TSP) 32.12- 21.23 mg EAG/g DW, and antioxidant capacity (AOX) for ABTS assay. The best treatment for TSP and AOX was T4: 2.5% Hibiscus w/w, aqueous extracts, decoction, extract-to-carrier ratio 1:1 (w/w), proportion to carriers (MD:GA) 80:20 (w/w), 10000 rpm, 150°C. Taguchi L8 model is a tool that allows the use of multiple variables with a low number of treatments that indicate the drying conditions that give the best parameters, focusing mainly on TSP and AOX, in addition, is a good alternative for the preservation and stability of the PC in Hibiscus.
COMMUNICATION | doi:10.20944/preprints201905.0163.v1
Subject: Materials Science, Surfaces, Coatings & Films Keywords: plasma spray; in-flight particles; molten status; YSZ
Online: 13 May 2019 (14:18:40 CEST)
In order to achieve better knowledge of the thermal barrier coatings (TBCs) by supersonic atmospheric plasma spraying (SAPS) process, an experimental study was carried out to elaborate physicochemical properties of particles in-flight during the SAPS process. One type of commercially available agglomerated and sintered yttria-stabilized-zirconia (YSZ) powders were injected into the SAPS plasma jet and collected by shock chilling method. The YSZ particles in-flight physicochemical properties of the melting state, morphology, microstructure, particle size distribution, element composition changes and phase transformation during the SAPS process have been systematically analyzed. The melting state, morphology and microstructure of the collected particles were determined by scanning electron microscopy (SEM). The particle size distribution was measured by a laser particle size analyzer (LPSA). Element compositions were quantitatively analysed by an electron probe X-ray microanalyzer (EPMA). Additionally, the X-ray diffraction (XRD) method was used to analyse the phase transformation. The results showed that the original YSZ powders injected into the SAPS plasma jet were quickly heated and melted from the outer layer companied with breakup and collision-coalescence. The outer layer of the collected particles containing roughly hexagonal shaped grains exhibited a surface texture with high sphericity and the inside was dense with hollow structure. The median particle size was decreased from 45.65 μm to 42.04 μm. Besides, phase transformation took place and the content of zirconium (Zr) and yttrium (Y) element was decreased with the evaporation of ZrO2 and Y2O3.
ARTICLE | doi:10.20944/preprints202207.0342.v1
Subject: Medicine & Pharmacology, Nutrition Keywords: COVID-19; CRP; vitamin D insufficiency; vitamin D spray
Online: 22 July 2022 (13:21:04 CEST)
Background: According to newly published studies, patients with Coronavirus Disease 2019 (COVID-19) have significantly lower serum 25-hydroxyvitamin D 25(OH)D levels than those without the SARS-CoV-2 infection. Vitamin D insufficiency may be a predictor of poor prognosis in COVID-19 patients. Vitamin D supplementation is related to improved clinical outcomes in terms of intensive care unit (ICU) admission and death, particularly in individuals with moderate-to-severe forms of COVID-19 requiring hospitalization. Materials and methods: This placebo-controlled five-day study was performed on 100 hospitalized COVID-19 patients with vitamin D insufficiency randomized into two groups. Vitamin D in the form of a sublingual sprayable microemulsion (LYL love your life® sunD3 LYLmicro™) was given three times daily after breakfast, lunch, and dinner (daily dose 12,000 IU) to 52 patients with blood vitamin D levels below 30 ng/ml. 48 patients in the control group received a placebo spray in the same daily regiment. Results: We observed a statistically significant increase by 8.6 ng/ml in median vitamin D level after five days of high-dose vitamin D3 spray therapy. 90.2% of subjects reached normal serum levels of vitamin D. There was a strong correlation between changes in vitamin D and C-reactive protein (CRP) levels in individuals with moderately severe disease (p<0.05), while mild and severe cases showed no statistical significance comparing case and control groups. There were no statistically significant changes in ferritin and interleukin-6 (IL-6) levels. Conclusions: In this study, we demonstrated the possibility to rapidly increase circulating levels of vitamin D just in 5 days of high-dose intervention and found a statistically significant decrease of CRP levels in patients with moderately severe COVID-19. We were not able to detect statistically significant changes in ferritin and IL-6 levels during the 5-day vitamin D intervention.
ARTICLE | doi:10.20944/preprints202203.0255.v1
Subject: Materials Science, Surfaces, Coatings & Films Keywords: spray dry; protein; encapsulation; formulation; excipient; core-shell; EISA
Online: 17 March 2022 (12:19:43 CET)
The encapsulation of proteins into core-shell structures is a widely utilised strategy for controlling protein stability, delivery and release. Despite the recognised utility of these microstructures, however, core-shell fabrication routes are often too costly or poorly scalable to allow for industrial translation. Furthermore, many scalable routes rely upon emulsion-techniques implicating denaturing or environmentally harmful organic solvents. Herein, we investigate core-shell protein encapsulation through single-feed, aqueous spray drying: a cheap, industrially ubiquitous particle-formation technology in the absence of organic solvents. We show that an excipient’s preference for the surface of the spray dried particle is well-predicted by its hydrodynamic diameter (Dh) under relevant feed buffer conditions (pH and ionic strength) and that the predictive power of Dh is improved when measured at the spray dryer outlet temperature compared to room temperature (R2 = 0.64 vs. 0.59). Lastly, we leverage these findings to propose an adaptable design framework for fabricating core-shell protein encapsulates by single-feed aqueous spray drying.
ARTICLE | doi:10.20944/preprints202008.0052.v1
Subject: Chemistry, Food Chemistry Keywords: Spray Drying; Vitamin C; Phenolic Compounds; Preservation; Modeling; Optimization
Online: 2 August 2020 (18:22:59 CEST)
Umbu is a tropical fruit with high content of bioactive compounds. However, maturation causes significant losses on nutrient density reducing the nutritional value of this highly appreciated fruit. Thus, the objective of the present work was to encapsulate the Umbu fruit bioactive compounds using spray drying and identify the variables affecting the biomolecules preservation. A Box-Behnken experimental design with 3 factors was set varying inlet temperature, atomization flow rate, and maltodextrin concentration for process otimization. Then the powder physicochemical and chemical properties were characterized, and results were modeled using a polynomial equation. Results revealed that the droplet size and maltodextrin concentration had a significant influence on the conservation of the biomolecules. Drying kinetics favoring fast formation of a particle crust increases encapsulation efficiency. Bioactive compounds retention was achieved by increasing maltodextrin even at high temperatures, where a matrix is formed hindering chemical degradation. Process optimization was validated and revealed low inlet temperatures (122ºC), high atomization flow rate (5kg/h) and high maltodextrin concentration (20%) to be the most desirable conditions for bioactive compounds retention.
ARTICLE | doi:10.20944/preprints202002.0002.v1
Subject: Engineering, Construction Keywords: construction; rainwater harvesting; solar; spray foam; finger-jointed studs
Online: 3 February 2020 (03:04:44 CET)
The question of building sustainable in a geographical locality is inexorably linked to cost. In 2011, one of the authors built a sustainable house that was (at the time) the highest certified sustainable home based on the National Association of Home Builder’s standards for sustainable construction. This Texas house has been used for residential and research purposes for the past decade. In this case study, the authors evaluate components of the construction and their effectiveness as well as unseen secondary and tertiary effects. Some of the specific components discussed are home site placement; rainwater harvesting (100% of residential requirements); aerobic septic system; grid-tied solar array power; electric car charging; geothermal heating and cooling; reclaimed wood framing; spray foam installation; selection of windows, fixtures, and appliances; on-demand electric water heaters for guest areas; generator backups; and use of local items. Electric bills and water system improvements are discussed in detail, as improvements were made as part of residential and research requirements. This case study suggests that the financial outlay is worth the extra up-front costs if residents in this geographical area and climate will occupy the residence 7 years.
ARTICLE | doi:10.20944/preprints201902.0192.v2
Subject: Materials Science, Surfaces, Coatings & Films Keywords: Anti-Glare; spray-coating; gloss; haze; response surface methodology
Online: 27 February 2019 (08:56:00 CET)
The process of preparing anti-glare thin films by spray-coating silica sol-gel to soda-lime glass was exclusively and statistically studied in this paper. The effects of sol-gel deliver pressure, air transport pressure, and spray gun displacement speed on the gloss, haze, arithmetic mean surface roughness, and total transmittance light were analyzed. The experimental results indicate that the factors of sol-gel deliver pressure, air transport pressure, and displacement speed exhibit significant effect on the haze, gloss, and Ra. In contrast, the variation of total transmittance light with these three factors are insignificant. Because the anti-glare property is predominantly determined by low gloss and high haze, therefore, we aim to minimize gloss and maximize haze to achieve high anti-glare. Central composite design and response rurface methodology are employed to analyze the main and interaction effects of the three factors through quadratic polynomial equations, which are confirmed by the analysis of variance and R2. The response surface methodology predict the lowest gloss and highest haze are 9.2 GU and 57.0%, corresponding to the sol-gel deliver pressure, air-transport pressure, and displacement speed of 250 kPa, 560 kPa, and 140 mm/s, and 340 kPa, 620 kPa, and 20 mm/s, respectively. Comparing the predicted optimal data with the real experimental results validates the applicability of the mathematical model. This study provides an important basis for the subsequent production of anti-glare glass with different specifications to satisfy the market demand.
REVIEW | doi:10.20944/preprints201809.0072.v1
Subject: Engineering, Mechanical Engineering Keywords: photo-catalysis, suspension plasma spray, thermal plasma, titanium oxide
Online: 4 September 2018 (15:08:47 CEST)
As a photo-catalytic titanium oxide film deposition process, thermal spray is hoped to be utilized practically on the condition that it is relatively easy to deposit anatase rich films. However, because of its high equipment and feedstock powder costs, it is very difficult to introduce thermal spray equipment into small companies. In this study, to develop a low cost thermal spray system, low power atmospheric suspension plasma spray equipment with titanium hydroxide suspension created by hydrolysis of titanium tetra iso butoxide using Ar, N2 as working gases. For avoiding sedimentation of the hydroxide particles in the suspension, mechanical milling of the suspension was conducted to create colloidal suspension before using it as feedstock. Moreover, an Ultrasonic wave container was used to keep the suspension particles moving while the spray process was conducted. After the film deposition, with As for the coating, anatase rich TiO2 ﬁlm could be obtained. For characterization of the film, microstructure observation by optical microscope and X-ray diffraction was carried out. Consequently, by creation of colloidal suspension, deposition could be conducted without sedimentation of the hydroxide particle in the suspension during operation. Besides, it was proved the film had enough photo-catalytic property to decolor methylene-blue droplet
ARTICLE | doi:10.20944/preprints202210.0107.v1
Subject: Earth Sciences, Environmental Sciences Keywords: occupational; environmental; health; organic solvents; automobile; workshop; spray painting; Brunei
Online: 9 October 2022 (04:18:58 CEST)
Automobile industries worldwide extensively use organic solvents. Yet, limited evidence examined the health and safety in handling these solvents, which can only be assured if workers have appropriate knowledge and demonstrate safe practices. A cross-sectional study was conducted to explore the knowledge and practice among workers who are involved with handling organic solvents in the automobile industry in the largest most urban district in Brunei Darussalam. Qualitative data were sought from open-ended questions; observations and pictorial evidence through still photographs. Quantitative analysis showed that 75% of the workers practice reading labels, 94.1% use fully covered clothes, 82.4% wear gloves and 98.5% practice proper hand washing as well as 98.5% cover container lids. The qualitative analysis illustrated workers have general knowledge of materials containing solvents but did not identify the exact solvents, the harmful effects of the solvents, pathophysiology and harmful effects on specific body systems. Health and safety were practiced albeit not consistent. Health and Safety Authorities in Brunei Darussalam must review and enforce specific policies on use of organic solvents so that they can be practiced consistently and safely in automobile industries. Cooperation and collaboration in adhering to the policies are mandatory to ensure health and safety at work.
REVIEW | doi:10.20944/preprints202207.0177.v1
Subject: Materials Science, Surfaces, Coatings & Films Keywords: dip-coating; spin-coating; spray-coating; blade-coating; roll-coating
Online: 12 July 2022 (09:01:50 CEST)
In this review, several cost-effective thin-film coating methods which include dip-coating, spin-coating, spray-coating, blade-coating, and roll-coating are presented. Each method has its set of advantages and disadvantages depending on the type of application. Not all of them are appropriate for large-scale production due to their certain limitations. That is why the coating method should be selected based on the type and size of substrate including the resolution of the required thin-films. The sol-gel method offers several benefits, such as simplicity in fabrication, excellent film uniformity, the capacity to cover surfaces of any size and over vast areas, and a low processing temperature. Nevertheless, these coating methods are somewhat economical and well managed in low-budget laboratories. Moreover, the produced thin-films are homogeneous and have low-surface roughness. Furthermore, some other thin-film deposition methods such as physical vapor deposition (PVD) and chemical vapor deposition (CVD) are also discussed. Since CVD is not restricted to line-of-sight deposition, a characteristic shared by sputtering, evaporation, and other PVD processes, many manufacturing methods favor it. However, these techniques require sophisticated equipment and cleanroom facility. We aim to provide the pros and cons of thin-film coating methods and let the readers decide the suitable technique for their specific application.
ARTICLE | doi:10.20944/preprints201906.0197.v1
Subject: Materials Science, Nanotechnology Keywords: L-ascorbic acid; Sodium alginate; Gum arabic; Spray-drying; Encapsulation
Online: 20 June 2019 (10:24:11 CEST)
The potential of sodium alginate (ALG) and gum arabic (GA) as wall polymers for L-ascorbic acid (AA) encapsulation as a tool for their preservation against the thermo-oxidative degradation was investigated. The influence of such polymers used as wall material on the AA-content, size, encapsulation efficiency, encapsulation yield and thermo-oxidative stability were evaluated. The AA-microparticles were obtained using the spray-drying technique. An experimental Taguchi design was employed to assess the influence of the variables in the encapsulation process. The microparticles morphology and size distribution were characterized by scanning electron microscopy and laser diffraction. The thermal stability of AA microparticles was studied by differential scanning calorimetry and thermogravimetry analysis. This work points out the viability to encapsulate AA using GA and ALG through a spray-drying process. In general, a product yield ranging from 35.1% to 83.2% and an encapsulation efficiency above 90% was reached. Spherical microparticles with a smooth surface were obtained with a mean diameter around 6 μm and 9 μm for the those prepared with GA and ALG, respectively. The thermo-oxidative analysis showed that both polymers allow maintaining AA stable up to 188 °C, which is higher than the traditional processing temperature used in the fish feed industry.
ARTICLE | doi:10.20944/preprints202301.0562.v1
Subject: Life Sciences, Virology Keywords: African swine fever; ASFV; spray-dried porcine plasma; challenge; nutritional intervention
Online: 31 January 2023 (02:21:18 CET)
The objective of this study was to evaluate the potential benefits of feeding spray-dried porcine plasma (SDPP) to pigs infected with African swine fever virus (ASFV). Two groups of twelve weaned pigs each were fed with CONVENTIONAL or 8% SDPP enriched diets. Two pigs (trojans)/group) were injected intramuscularly with the pandemic ASFV (Georgia 2007/01) and comingled with the rest of the pigs (1:5 trojan:naïve ratio) to simulate a natural route of transmission. Trojans developed ASF and died within the first week after inoculation but contact pigs did not develop ASF, viremia or seroconversion. Therefore, three more trojans per group were introduced to optimize the ASFV transmission (1:2 trojan:naïve ratio). Blood, nasal and rectal swabs were weekly harvested and at end of the study, ASFV-target organs collected. After the second exposure, rectal temperature of conventionally fed contact pigs increased >40.5˚C while fever was delayed in the SDPP contact pigs. Additionally, PCR Ct values in blood, secretions and tissue samples were significantly lower (P<0.05) for CONVENTIONAL compared to SDPP contact pigs. Under these study conditions, contact exposed pigs fed SDPP had delayed ASFV transmission and reduced virus load, likely by enhanced specific T-cell priming after the first ASFV-exposure.
ARTICLE | doi:10.20944/preprints202110.0428.v1
Subject: Materials Science, Polymers & Plastics Keywords: evaporation; poly (vinylidene fluoride); crystallization; droplet; coffee ring effect; ultrasonic spray
Online: 28 October 2021 (09:55:59 CEST)
The evaporation of polymer solution droplet is an important in solution-based polymer film fabrications, such as inkjet print, spray coatings, and droplet casting etc. In this work, we investigated the effect of droplet size, solvent evaporation rate, and concentration on “coffee-ring” effect, crystal nucleation, polymorphism, and morphology of dried poly (vinylidene fluoride) (PVDF) solution droplets with atomic force microscopy (AFM) method. We found that the crystal structure, morphology and crystal distribution in the center and edge regions of dried PVDF droplets were different due to “coffee-ring” effect. The “coffee-ring” effect of dried PVDF droplets was mainly composited of accumulated crystals at the edge region of droplet, which was mainly made by crystallization of migrated chains. The interplay between migration of chains, crystallization and solidification of PVDF droplets significantly influenced the formation of “coffee-ring”. In addition, our results showed that the decrease of droplet size and controlling solvent evaporation rate were effective ways to improve the PVDF β-phase nucleation and decrease crystal size.
ARTICLE | doi:10.20944/preprints201811.0553.v1
Subject: Materials Science, Surfaces, Coatings & Films Keywords: graphene; hydroxyapatite; crystallinity; surface roughness; heat and hydrothermal treatment; plasma spray
Online: 22 November 2018 (15:08:21 CET)
Recent advances and demands in clinical applications drive a large amount of research to hydroxyapatite (HA) composite coatings fabricated by plasma spray. However, lower degree of HA crystallinity related to high temperature exposure in plasma spray usually leads to rapid weakening and disintegration of HA coatings and often promotes inflammatory responses in the surrounding tissue. In this research, graphene nanosheet (GNS) reinforced HA coatings were fabricated using plasma spray and followed by heat and hydrothermal treatment (hereafter referred to as thermal treatment). The addition of GNSs resulted in competing phenomenon to influence HA crystallinity viz. increased portion of the partially melted/unmelted zones and higher cooling rate during splat formation, leading to slight increase in HA crystallinity (~46.0-51.3%) in the as-sprayed coating. XRD and FTIR results showed that thermal treatment was capable of inducing significant transformation of amorphous HA to the crystalline form and removing other foreign non-HA compounds through regaining OH- ion, and therefore HA coatings displayed ~45.5-47.1% improvements in HA crystallinity regardless of addition or not of the GNS nanofillers. Microstructure observations revealed that thermal treatment enabled microcrack propagation due to stresses caused by crystallisation and phase transformations, and the residual partially melted/unmelted zone of the thermally treated GNS/HA coating was significantly decreased in size. More importantly, the added GNSs contributed greatly to the significant increase in surface nanoroughness of the thermally treated HA coatings owing to the fact that much more structural defects along with the GNSs mainly induced by thermal treatment might act as nucleation sites to accelerate HA nanoparticle precipitation, which would be beneficial for the improved adhesion strength of the osteoblast cells on the coating surface.
ARTICLE | doi:10.20944/preprints201807.0448.v1
Subject: Materials Science, Surfaces, Coatings & Films Keywords: X-ray tomography; cold spray; porosity; stainless steel; three-dimensional imaging
Online: 24 July 2018 (07:50:30 CEST)
Cold gas-dynamic spray (cold spray) is an evolving coating deposition and restoration technology in which particles are deposited above the sonic speed. This paper presents the non-destructive three-dimensional characterization of cold sprayed stainless steel coating. The visualization of coating morphology and volumetric porosity, and the analyses of porosity size and spatial distributions confirmed that dense stainless steel coating with non-connected, micron-sized gradient porosity is successfully produced by cold spray. The suitability of X-ray tomography for characterizing cold sprayed coatings is assessed.
ARTICLE | doi:10.20944/preprints202111.0364.v1
Subject: Engineering, Biomedical & Chemical Engineering Keywords: Polymeric micelles; cannabidiol (CBD); spray-drying; ocular drug delivery; corneal epithelial cells
Online: 19 November 2021 (14:48:27 CET)
Ocular drug delivery is one of the most challenging administration routes due to the very low drug bioavailability. In this work, we produce and characterize mucoadhesive mixed polymeric micelles (PMs) made of chitosan and poly(vinyl alcohol) backbones graft-hydrophobized with short poly(methyl methacrylate) blocks and use them to encapsulate cannabidiol (CBD), an anti-inflammatory cannabinoid. CBD-loaded mixed PMs are physically stabilized by ionotropic crosslinking of the CS domains with sodium tripolyphoshate and spray-drying. These mixed PMs display CBD loading capacity of 20% w/w and sizes of 100-200 nm, and spherical morphology (cryogenic-transmission electron microscopy). The good compatibility of the unloaded and CBD-loaded PMs is assessed in a human corneal epithelial cell line. Then, we confirm the permeability of CBD-free PMs and nanoencapsulated CBD in cornea cell monolayers under liquid-liquid and air-liquid conditions. Overall, our results highlight the potential of these polymeric nanocarriers for ocular drug delivery.
ARTICLE | doi:10.20944/preprints202101.0042.v1
Subject: Earth Sciences, Environmental Sciences Keywords: inhalation exposure assessment; computational fluid dynamics (CFD); biocides; spray model; unsteady RANS
Online: 4 January 2021 (13:17:30 CET)
Consumer products contain the chemical substances that threaten human health. The modeling methods and experimental methods have been used to estimate the inhalation exposure concentration by the consumer products. The model and measurement methods have the spatial property problem and time/cost consuming problem, respectively. For solving the problems due to the conventional methodology, this study performed the feasibility of applying CFD for evaluation of inhalation exposure by comparing the experiment results and the zero-dimensional results with CFD results. To calculate the aerosol concentration, the CFD was performed by combined the 3D Reynolds averaged Navier Stoke’s equation and discrete phased model using ANSYS FLUENT. As a result of comparing the three methodologies performed under the same simulation/experimental conditions, we found the zero-dimensional spray model shows approximately 5 times underestimated inhalation exposure concentration when compared with the CFD results and measurement results in near field. Also, the results of the measured concentration of aerosols at five locations and the CFD results at the same location were compared to show the possibility of evaluating inhalation exposure at various locations using CFD instead of experimental method. The CFD results according to measurement positions can predict rationally the measurement results with low error. In conclusion, in the field of exposure science, a guideline for exposure evaluation using CFD was found that complements the shortcomings of the conventional methodology, the zero-dimensional spray model and measurement method.
ARTICLE | doi:10.20944/preprints201909.0163.v1
Subject: Engineering, Control & Systems Engineering Keywords: Artificial Neural Network (ANN); classification; image analysis; chokeberry powder; colors; spray-drying
Online: 16 September 2019 (11:04:14 CEST)
The study concentrates on researching possibilities of using computer image analysis and neural modeling in order to assess selected quality discriminants of spray-dried chokeberry powder. The aim of the paper is quality identification of chokeberry powders on account of their highest dying power, the highest bioactivity as well as technologically satisfying looseness of powder. The article presents neural models with vision technique backed up by devices such as digital camera as well as electron microscope. Reduction in size of input variables with PCA has influence on improving the processes of learning data sets, thus increasing effectiveness of identifying chokeberry fruit powders included in digital pictures, which is shown in the results of the conducted research. The effectiveness of image recognition are presented by classifying abilities as well as low Root Mean Square Error (RMSE), for which the best results are achieved with typology of network type Multi-Layer Perceptron (MLP). The selected networks type MLP are characterized by the highest degree of classification at 0.99 and RMSE at 0.11 at most at the same time.
ARTICLE | doi:10.20944/preprints201901.0138.v2
Subject: Materials Science, Surfaces, Coatings & Films Keywords: Ga-doped ZnO; chemical spray technique; XRD; AFM; Optical properties; Electrical properties.
Online: 5 March 2019 (11:23:31 CET)
Ga doped ZnO thin films were formed by the Ultrasonic Chemical Spray Pyrolysis method onto substrates using zinc acetate and gallium (III) nitrate hydrate as precursors. The structural, optical, surface and electrical properties were studied as a function of increasing Ga doping concentration from 0 to 6 at %. Structural studies were shown polycrystalline with a hexagonal crystal structure. The transparency in the visible range was around 85% for thin film deposited using 6 at % Ga doping. With the aim of determining surface images and surface roughness of the films atomic force microscope images were taken. Ga doping of ZnO thin films could markedly decrease surface roughness. Electrical resistivity was determined by four point method. The resistivity 2.0% Ga doped ZnO film was the lowest resistivity of 1.7 cm. In the photoluminescence measurements of the films, existence of UV and defect emission band was observed. As a result, Ga doped ZnO films have advanced properties and promising materials for solar cells.
ARTICLE | doi:10.20944/preprints202301.0564.v1
Subject: Life Sciences, Virology Keywords: African swine fever; ASFV; spray-dried porcine plasma; vaccine; challenge; nutritional interven-tion
Online: 31 January 2023 (02:24:23 CET)
This study aimed to evaluate the effects of feeding spray-dried porcine plasma (SDPP) on the protection afforded by the BA71∆CD2 African swine fever virus (ASFV) vaccine prototype. Two groups of pigs ac-climated to diets without or with 8% SDPP were intranasally inoculated with 105 plaque forming units (PFU) of live attenuated ASFV strain BA71∆CD2 and three weeks later left in direct contact with pigs infected with the pandemic Georgia2007/01 ASFV strain. During the post-exposure (pe) period, 2/6 from the conventional diet group showed a transient peak rectal temperature >40.5ºC before day 20 pe and some tissue samples collected at 20 d pe from 5/6 were PCR+ for ASFV, albeit showing Ct values much higher than Trojan pigs. Interestingly, the SDPP group did not show fever, neither PCR+ in blood nor rectal swab at any time pe and none of the postmortem collected tissue samples were PCR+ for ASFV. Differential serum cytokine profiles among groups at vaccination, and a higher number of ASFV-specific IFNϒ-secreting T-cells in pigs fed with SDPP soon after the Georgia2007/01 encounter, confirmed the relevance of Th1-like responses in ASF pro-tection. We believe that our result show that nutritional interventions might contribute to improve future ASF vaccination strategies.
REVIEW | doi:10.20944/preprints202211.0169.v1
Subject: Life Sciences, Virology Keywords: viroid; resistance; tolerance; RNA silencing; plant hormone; spray-induced gene silencing; genome editing
Online: 9 November 2022 (03:10:00 CET)
Viroids are known the smallest plant pathogens, and although their genome sequences do not encode proteins, they can cause disease in economically important crops. In order to control viroid diseases and mitigate their damage, genetic resources used for breeding of the viroid-resistant crop have been searched, but the practical resistant trait has not been found in almost all viroid-crop combinations, as well as the tolerant trait. Due to the difficulty in exploiting naturally occurring resistance or tolerance, various effective strategies have been devised to control viroid diseases using non-transforming or transforming techniques. Meanwhile, extensive findings related to viroid resistance and tolerance may lead to confer resistance or tolerance to viroid infection by combining with the recently emerged new technologies (e.g., spray-induced gene silencing and genome-editing technologies), which are believed to be more environmentally viable and acceptable to the general public than previously reported approaches. In particular, some genome-modified crops produced by the latter technology are already on the market. In this review, we comprehensively summarize the current status about investigation of naturally occurring genetic traits for viroid resistance and tolerance, accumulating knowledge about host factors involved in viroid pathogenicity, and various basic technologies developed to try to possible viroid disease control strategies. Furthermore, we discuss prospects and challenges for the achievement of more effective, practical, and sustainable disease control of viroid.
ARTICLE | doi:10.20944/preprints202111.0572.v1
Subject: Physical Sciences, Other Keywords: Nickel oxide; Thin films; Al doping ratio; Solar spray pyrolysis; Solar heater; Furnace.
Online: 30 November 2021 (13:29:11 CET)
In this experimental work, pure nickel oxide and Al-doped NiO thin films have successfully been elaborated onto glass substrates by solar spray pyrolysis technique. The substrates were heated at around 450°C using a solar heater (furnace). The structural, optical and electrical properties of the elaborated Al-doped films have been studied at different atomic percentage ratios (0, 0.5, 1, 1.5 and 2 at. %). The results of Al-doped NiO films XRD patterns were, the formation of (NiO) phase under a cubic crystalline structure (polycrystalline) with a strong favored orientation along (111) plane were noticed at all sprayed films. When Al doping ratio reaches 1 at.%, an growth in crystallite size over 31.9 nm was obtained denoting the nano-structure of the product, which confirmed by SEM images. In addition, aluminum oxide Al2O3 was clearly observed at 1.5 at.% Al ratio. Otherwise, all thin films have a good optical transmission in the visible region of about 65%, the optical band gap energy decreased from 3.69 to 3.64 eV with increasing Al doping ratio. It is shown that the layer deposited with 0.5 at.% has less disorder with few defects. The investigation on electrical properties of elaborated thin films confirmed that the conductivity of NiO films was improved, after doping them with Al which affirms their p-type character of semiconductor. However, an addition of an excessive quantity of Al content causes the formation of Al2O3 which leads to a decrease in the conductivity. It is worth mentioning that the Al content of 0.5 at.% is the optimum ratio in terms of electrical conductivity and formation defect. Al-doped NiO can be used in various optoelectronic devices due to its good transparency and high electrical conductivity.
ARTICLE | doi:10.20944/preprints202102.0280.v1
Subject: Life Sciences, Biochemistry Keywords: Double stranded RNA; Nano clay; Phytophthora infestans; Potato; Spray Induced gene silencing (SIGS)
Online: 11 February 2021 (11:07:19 CET)
Phytophthora. infestans is a well known late blight causing oomycetes pathogen. It evolves and adapts to the host background and new fungicide molecules rapidly within a few years of their release, may be due to the predominance of transposable elements in its genome. Frequent and huge applications of fungicides cause environmental concerns. Here we developed target specific RNA interference based molecules, that are capable of effectively reducing the late blight infection. cDNA microarray expression data was used for the selection of genes involved in the early stage of infection process, sporulation etc. The in vitro synthesis of double stranded RNA molecule, targeting SDH, EF-1α, GPI-HAM344, PLD-3 and HSP-90 encoding genes revealed the reduction in growth, sporulation and symptom expression, which were subsequently assessed by culture bioassay, detached leaf assay and topical application methods. The multiple genes targeted dsRNA nano clay sprayed plants showed enhanced disease resistance (4% disease severity) and least sporulation (<1x103), compared to naked dsRNA spray. Use of nano clay was assumed to be involved in the effective delivery, protection and boosting the action of RNAi in potato plants. A significant difference in the growth, sporulation count, disease severity and reduced expression of the genes and confocal microscopy imaging authenticates the effects of SIGS on late blight disease progression. Our research demonstrated that topical dsRNA nano clay spray under the open-air environment could be an alternative to chemical fungicides and transgenic approaches as a novel plant protection strategy for late blight in an environmentally friendly manner.
ARTICLE | doi:10.20944/preprints201901.0070.v1
Subject: Engineering, Mechanical Engineering Keywords: axial and radial suspension plasma spray, commercial suspensions, viscosity, surface tension, coatings microstructures
Online: 8 January 2019 (15:10:25 CET)
The demand for suspensions used in thermal spray processes is expanding from research labs using the lab-prepared suspensions toward actual coating production in different industrial sectors. Industrial applications dictate reduced production time and effort which may in turn justify the development of the market for ready-to-use commercial suspensions. To this end, some of the powder suppliers have already taken steps forward by introducing to the market suspensions of some of the most used materials such as yttria-stabilized zirconia (YSZ), alumina and titania. There is, however, a need to compare the suspension characteristics over time and the resultant coatings when using these suspensions as compared with the freshly prepared home-made suspensions. In this work, such comparison is done using YSZ suspensions of the sub-micron to a few micron powders. In addition, some changes in the suspensions' formula were performed as a tool to vary the coatings’ microstructures in a more predictable way, without variation of spray parameters. The coatings were generated using both radial and axial injection of the suspensions into Oerlikon-Metco 3MB and Mettech Axial III plasma spray torches, respectively. A clear effect of suspension viscosity on the coating microstructure was observed using the 3MB torch with radial injection of suspension (i.e. cross flow atomization). The viscosity role, however, was not dominant when using the Axial III torch with axial feed injection system (i.e. coaxial flow atomization).
ARTICLE | doi:10.20944/preprints202111.0206.v1
Subject: Biology, Entomology Keywords: Indoor residual spray (IRS); Vector control; Anopheles; Aedes aegypti; Culex quinquefasciatus; Neonicotinoids; Pyrethroid; Insecticide resistance; SumiShield; K-Othrine.
Online: 10 November 2021 (14:24:24 CET)
Insecticides with novel modes of action are required to complement the pyrethroids currently relied upon for controlling malaria vectors. One example of this is the neonicotinoid clothianidin, which is found in SumiShield™ 50WG used in indoor residual spraying (IRS). In a preliminary experiment, mortality in insecticide susceptible and resistant An. gambiae adults exposed to SumiShield™ 50WG-treated filter papers reached 80% by 3-days post-exposure and 100% by 6-days post-exposure. Next, cement, wood, and mud tiles were treated with SumiShield™ 50WG or K-Othrine® WG250 (deltamethrin IRS formulation) and insecticide resistant and susceptible Anopheles and Aedes were exposed to these surfaces periodically for up to 18-months. Pyrethroid resistant Cx. quinquefasciatus were also exposed at 9 months. Between exposures tiles were stored in heat and relative humidity conditions reflecting those found in the field. On these surfaces, SumiShield™ 50WG was effective at killing both susceptible and resistant An. gambiae for 18 months post-treatment, while mortality amongst the resistant strains when exposed to deltamethrin (K-Othrine® WG250) IRS was not above that of the negative control. Greater efficacy of SumiShield™ 50WG was also demonstrated against insecticide resistant strains of An. funestus compared to deltamethrin, though the potency was lower when compared with An. gambiae. In general, a higher efficacy of SumiShield™ 50WG was observed on cement and mud compared to wood. SumiShield™ 50WG demonstrated poor residual activity against Aedes aegypti and Culex quinquefasciatus. Overall, the results suggest SumiShield™ 50WG is well suited for malaria control.
Subject: Materials Science, Surfaces, Coatings & Films Keywords: atmospheric plasma spray (APS) process; particle size; thermal insulation; thermal barrier coating (TBC); thermal diffusivity; coating microstructure; coating porosity
Online: 3 July 2019 (14:49:12 CEST)
In the present work, three different atmospheric plasma sprayed (APS) alumina coatings were fabricated using three fused and crushed alumina powders of different particle size fine, medium and coarse. The influence of the particle size on thermal properties and micro-structural features of the produced coating were investigated by thermal insulation test and detailed image analysis technique, respectively. The analyzed micro-structural features include the total porosity, pore size (fine, medium, and large) and cracks. All types of cracks were considered in calculations as voids and were evaluated according to their sizes as pores. All spray parameters except the particle size were fixed throughout the spraying process. The results revealed that the fine starting powder has produced the densest coating with the lowest total porosity and that the total porosity increases with an increasing particle size. This was expected as powders of smaller particle size will reach a higher in-flight temperature and velocity than powders of bigger particle sizes as long as the same spray parameters are applied. However, a detailed image analysis investigation on the three produced coatings showed that the fraction of fine pores and cracks versus the total porosity is substantially higher in coatings produced by using fine starting powders than those produced using medium and coarse powders. In this work, a connection between the thermal insulation and the porosity fraction, which includes fine pores and cracks, was revealed.
Subject: Materials Science, Nanotechnology Keywords: Sepiapterin; triacetyl-β-cyclodextrin (TAβCD); hydrophilic drug/cyclodextrin complexes; spray-drying; methoxy-poly(ethylene-glycol)-poly(epsilon-caprolactone) (mPEG-PCL) nanoparticles
Online: 24 May 2019 (11:42:42 CEST)
In this work, we investigated for the first time the complexation of sepiapterin (SP), the natural precursor of the natural essential cofactor tetrahydrobiopterin, that displays mild water-solubility and short biological half-life, with the hydrophobic triacetyl-β-cyclodextrin (TAβCD) to improve its encapsulation within methoxy-poly(ethylene-glycol)-poly(epsilon-caprolactone) (mPEG-PCL) nanoparticles. First, TAβCD-SP complexes were produced by spray-drying of TAβCD/SP binary solutions by utilizing the Nano Spray Dryer B-90 HP. Then, dry powders were characterized by differential scanning calorimetry (DSC), Fourier-transform infrared spectroscopy (FTIR) and transmission and scanning electron microscopy (SEM and TEM, respectively) and compared to the complex components and physical mixtures (PMs). Next, SP was encapsulated within methoxy-poly(ethylene-glycol)-poly(epsilon-caprolactone) (mPEG-PCL) nanoparticles by nanoprecipitation of a SP/TAβCD complex/mPEG-PCL solution. In addition to complex nanoencapsulation, we assessed encapsulation of pure SP by nanoprecipitation with an intermediate step, which comprised the co-drying of SP, TAβCD and mPEG-PCL copolymer solution in organic solvent; this step aimed to promote the formation of molecular interactions between SP, TAβCD and the PCL blocks in the copolymer. SP-loaded mPEG-PCL nanoparticles were characterized by dynamic light scattering (DLS) and SEM. Nanoparticles with size of 74-75 nm and small polydispersity index (PDI <0.1) were obtained when SP-TAβCD equimolar spray-dried complex was used for nanoencapsulation, and SEM analysis indicated the absence of free SP crystals. Moreover, the encapsulation efficiency (%EE) and drug loading (DL) were 85% and 2.6%, respectively, as opposed to those achieved with pure SP encapsulation (14% and 0.6%, respectively). Overall, our results confirm that spray-drying of SP/TAβCD solutions at the appropriate molar ratio leads to the hydrophobization of the relatively hydrophilic SP molecule, enabling its encapsulation within mPEG-PCL nanoparticles.