The nature of the blue color in the iodine-starch reaction (or, in most cases, iodine-iodide-starch reaction, i.e. as I2 as well as I- are typically present) has for decades elicited debate. The intensity of the color suggests a clear charge-transfer nature of the band at ~600 nm, and there is consensus regarding the fact that the hydrophobic interior of the amylose helix is the location where iodine binds. Three types of possible sources of charge transfer have been proposed: (1) chains of neutral I2 molecules, (2) chains of poly-iodine anions (complicated by the complex speciation of the I2 - I- mixture), or (3) mixtures of I2 molecules and iodide or polyiodide anions. An extended literature review of the topic is provided here. According to the most recent data, the best candidate for the “blue complex” is a I2-I5-I2 unit – expected to occur in repetitive manner inside the amylose helix.

The kiwiberry is a trendy variety that shows a high demand for consumption but presents commercialization challenges due to its short life. The purpose of this study is to compare the effects of edible alginate coatings in prolonging the shelf life of this fruit. Two different forms were tested (coarse emulsions(C) and nanoemulsions(N)) and the effects of two different coating application techniques (spraying(S) and dipping(D)) were tested. Additionally, the use of Vis-NIR for quality monitorization was assessed as well. Fruits were treated with ten different treatments, using the following base formulations:Alginate(AL) 2%(w/v) enriched with eugenol(Eug) and citral(Cit) at minimum inhibitory concentrations (0.10% and 0.15%) and double MIC. Samples were taken from cold storage (0° C), at 2 and 4 weeks. For fruit quality evaluation, colour analysis, firmness, soluble solids content, dry matter and weight loss were performed. During storage, the colour and SSC parameters increased. Firmness decreased over time.Weight loss was the parameter with higher significant differences, increasing over time and more pronounced in treatments with higher essential oils components. This study suggests that AL-S, AL-D, AL-Cit 0.15+Eug0.1-N-S, AL-Cit0.15+Eug0.1-N-D and AL-Cit0.15+Eug0.1-C-D can preserve kiwiberries quality. Moreover, we verify that the Vis-NIR spectral analysis could be beneficial for performing coatings discrimination.

Agricultural soils serve as crucial storage sites for soil organic carbon (SOC). Their appropriate management is pivotal for mitigating climate change. To evaluate spatial and temporal changes in SOC within agricultural fields, continuous monitoring is imperative. In-field data sets of Vis-NIR soil spectra were collected on a long-term experimental site using an on-the-go spectrophotometer. Data processing for continuous SOC prediction involves a two-steps modelling approach. In Step 1, a Partial Least Square (PLSR) regression model is trained to establish a relationship between the SOC content and the spectral information also including spectral preprocesisng. In Step 2, the predicted SOC content obtained from the PLSR models is interpolated using ordinary kriging. Among the tested spectral preprocessing techniques and semivariogram models, SG and gapDer preprocessing along with a Gaussian semivariogram model, yielded the best performance resulting in a root mean square error of of 1.24 and 1.26 g kg-1. A striping effect due to the transect-based data collection was addressed by testing the effectiveness of extending the spatial separation distance, employing data aggregation, and defining the distribution based on treatment plots using block kriging. Overall, the results highlight the immense potential of on-the-go spectral Vis-NIR data for field-scale spatial-temporal monitoring of SOC.

The manuscript presents the optical properties of directly deposited films of gold nanoparticles (AuNPs) prepared by ultrasonic spray pyrolysis technology. Four samples were produced, with an AuNPs deposition time of 15 min, 30 min, 1h and 4h on the glass substrate. The morphological characterization of the deposited films showed that the size of the first deposited AuNPs is between 10 and 20 nm, while with a longer duration of the deposition process, larger clusters of AuNPs grow by coalescence and aggregation. The prepared layers were optically characterised with Ultraviolet–visible spectroscopy (UV-vis) and ellipsometry. The ellipsometric measurements showed an increasingly denser and thicker effective thickness of the AuNPs layers. The extinction spectra display a clear local surface plasmonic resonance (LSPR) signature (peak 520-540 nm), indicating the presence of isolated particles in all samples. For all AuNPs layers, the imaginary part of both ε// and ε⏊ is dominated by a central peak around 2.2 eV corresponding to the LSPR of isolated particles and a high-energy shoulder due to Au interband transitions. It is shown that, as the density of particles increases, the extinction cross section grows over the whole spectral range where measurements are taken. Thus response can be explained with an enhanced electromagnetic response among AuNPs, that can be connected to the increase of particle density but also by the formation of clusters and irregular structures.

Optical sensor data can be used to determine changes in anthocyanins, chlorophyll and soluble solids content (SSC) in apple production. In this study, visible and near-infrared spectra (729 to 975 nm) were transformed to SSC values by advanced multivariate calibration models i.e. partial least square regression (PLSR) in order to test the substitution of destructive chemical analyses through non-destructive optical measurements. Spectral field scans were carried out from 2016 to 2018 on marked ’Braeburn’ apples in Southwest Germany. The study combines an in-depth statistical analyses of longitudinal SSC values with horticultural knowledge to set guidelines for further applied use of SSC predictions in the orchard to gain insights into apple carbohydrate physiology. The PLSR models were investigated with respect to sample size, seasonal variation, laboratory errors and the explanatory power of PLSR models when applied to independent samples. As a result of Monte Carlo simulations, PLSR modelled SSC only depended to a minor extent on the absolute number and accuracy of the wet chemistry laboratory calibration measurements. The comparison between non-destructive SSC determinations in the orchard with standard destructive lab testing at harvest on an independent sample showed mean differences of 0.5 % SSC over all study years. SSC modelling with longitudinal linear mixed-effect (LME) models linked high crop loads to lower SSC values at harvest and higher SSC values for fruit from the top part of a tree.

Cyanobacterial mass developments in eutrophic ponds and lakes are a major concern for lake management, as many cyanobacteria produce a huge variety of toxic secondary metabolites, e.g. microcystins. The aim of this research was to culture a strain of the cyanobacterium Microcystis sp strain BM25, to observe its biomass production and to isolate and purify protease inhibitors from this cyanobacterial biomass. Different secondary metabolites were isolated following a standard bioassay-guideline. Isolation was performed, with an enzymatic protease assay as bioassay. High performance liquid chromatography was used to identify different fractions of secondary metabolite from the strain BM25. Moreover, protease homogenates were isolated from Daphnia magna in order to test the inhibitors against naturally occurring major digestive proteases trypsin and chymotrypsin. It was measured that 60% MeOH and the 80% MeOH C18-SPE fraction inhibits chymotrypsin activity 98% (6 nmol pNA min^-1 mg^-1) and 99 % (4 nmol pNA min^-1 mg^-1), respectively. In contrast, trypsin activity was not inhibited by methanolic extracts of this cyanobacterium strain.

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.

Gold nanoparticles (AuNPs) exhibit improved optical and spectral properties compared to bulk materials, making them suitable for detection of DNA, RNA, antigens, and antibodies. Here, we describe a simple, selective, and rapid non-cross linking detection assay, using approx. 35 nm spherical Au nanoprobes, for a common mutation occurring in exon 19 of the epidermal growth factor receptor (EGFR), associated with non-small cell lung cancer cells. AuNPs were synthesized based on the seed-mediated growth method and functionalized with a specific 16 bp thiolated oligonucleotide using a pH-assisted method. Both AuNPs and Au nanoprobes proved to be highly stable and monodisperse by ultraviolet-visible spectrophotometry, dynamic light scattering (DLS) and electrophoretic light scattering (ELS). Our results indicate a detection limit of 1.5 µg mL−1 using a 0.15 nmol dm−3 Au nanoprobe concentration. In conclusion, this work is an effective possibility for a straight-forward, fast, and inexpensive alternative for the detection of DNA sequences related to lung cancer, leading to a potential platform for an early diagnosis of lung cancer patients.

In this work, we report manganese phthalocyanine (MnPc) films obtained by ultrasonic spray-pyrolysis technique at 40°C deposited on glass substrate subjected to thermal annealing at 100 °C and 120°C. The MnPc films were characterized by UV/Vis spectroscopy, Raman spectroscopy, X-Ray Diffraction (XRD) and Scanning Electron Microscopy (SEM). The absorption spectra of the MnPc films were studied in a wavelength range from 200 to 850 nm, where the characteristic bands of a metallic phthalocyanine known as B and Q bands were observed in this range of the spectrum. The optical energy band (Eg) was calculated by the Tauc equation. It was found that for these MnPc films, the Eg has the values of 4.41, 4.46 and 3.58 eV corresponding to as deposited, annealing 100°C and 120°C, respectively. The Raman spectra of the films showed their characteristic vibrational modes of the MnPc films. In X-ray diffractograms of these films, the characteristic diffraction peaks of a metallic phthalocyanine are observed, presenting a monoclinic phase. SEM images of these films were studied in cross section obtaining thicknesses of 2, 1.2 and 0.3 μm to as deposited, annealing 100°C and 120°C, successively. Also, in the SEM images of these films, both the average particle sizes ranging from 4 to 0.041 µm and the average diameter from 4.8 to 0.091 μm were obtained. The results agree with those reported in the literature for MnPc films deposited with other techniques.

There is experimental evidence of high vibronic activity that accompanies the strongly allowed transition between the ground state and the lowest electronic singlet excited state of oligofurans that contain 2,3, and 4 furan rings. The absorption and emission spectra of the three lowest oligofurans measured in liquid nitrogen temperature show distinct fine structures that are reproduced using the projection-based model of vibronic coupling (with Dushinsky rotation included) parameterized utilizing either DFT (with several different exchange-correlation functionals) or ab initio (CC2) quantum chemistry calculations. Using as reference the experimental data concerning the electronic absorption and fluorescence for the 8 lowest oligofurans we first analyze the performance of the exchange-correlation functionals for the electronic transition energies and the reorganization energies. Subsequently, we use the best functionals alongside the CC2 method to explore how the reorganization energies are distributed among the totally symmetric vibrations, identify the normal modes that dominate in the fine structures present in the absorption and emission bands, and trace their evolution with the increasing number of rings in the oligofuran series. Confrontation of the simulated spectra with the experiment allows for verification of the performance of the selected DFT functionals and the CC2 method.

Glass samples (59.5 – x) B2O3 – 20Na2O – 20CaO – xV2O5 – Er2O3 – 0.5AgCl (x = 0 – 2.5 mol%) were prepared using melt – quenching method to investigate the structural and optical properties of the glass. The structural of the glass were characterized by using XRD, TEM and FTIR, meanwhile the optical properties were characterized by UV – VIS absorption. The XRD patterns confirmed the amorphous nature of the prepared glass samples. FTIR confirmed the presence of VO4, VO5, BO3, and BO4 vibration, and this result showed NBO increased with increasing vanadium concentration. The UV – Vis – NIR spectra exhibits six absorption band centered at 490, 520, 540, 660, 800, and 980 nm. The optical band gap (Eopt), Urbach energy and refractive index shown decrease, increase and increase, respectively. The Judd – Ofelt intensity parameter reveal the trends was Ω2 > Ω4 > Ω6. There are three emission bands at 516 nm, 580 nm, and 673 nm which are represented by 2H11/2 – 4I15/2, 4S3/2 – 4I15/2, and 4F15/2 – 4I15/2, respectively under 800 nm excitation was obtained.

Petrosamine (1) – a colored pyridoacridine alkaloid from the Belizean sponge, Petrosia sp. that is also a potent inhibitor of acetylcholine esterase (AChE) – was investigated by spectroscopic and computational methods. Analysis of the petrosamine free energy landscapes, pKa and tautomerism revealed an accurate electronic depiction of the molecular structure of 1 as the di-keto form, with net charge of q = +1, rather than a dication (q = +2) under ambient conditions of isolation-purification. The pronounced solvatochromism (UV-vis) reported for 1, and related analogs, was investigated in detail and is best explained by charge delocalization and stabilization of the ground state (HOMO) of 1 rather than an equilibrium of competing tautomers. Refinement of the molecular structure of 1 by QM methods complements published computational docking studies to define the contact points in the enzyme active site that may improve design of new AChE inhibitors based on the pyridoacridine alkaloid molecular skeleton.

This joint experimental-theoretical work focuses on molecular and photophysical properties of the spiropyran-containing amphiphilic molecule in organic and aqueous solutions. Being dissolved in tested organic solvents, the system demonstrates positive photochromism, i.e. upon UV stimulus the colorless spiropyran form is transformed into colorful merocyanine isomer. However, aqueous solution of the amphiphile possesses a negative photochromism: the orange-red merocyanine form turns to be thermodynamically more stable in water, and both UV and vis stimuli lead to the partial or complete photobleaching of the solution. The explanation of this phenomenon is given on the basis of density functional theory calculations and classical modeling including thermodynamic integration. The simulations reveal that stabilization of merocyanine in water proceeds with the energy of ca. 70 kJ mol−1, and that the Helmholtz free energy of hydration of merocyanine form is 100 kJ mol−1 lower as compared to the behavior of SP isomer in water. The explanation of such a difference lies in the molecular properties of the merocyanine: after ring-opening reaction this molecule transforms into a zwitterionic form, as evidenced by the electrostatic potential plotted around the opened form. The presence of three charged groups on the periphery of a flat conjugated backbone stimulates the self-assembly of merocyanine molecules in water, ending up with the formation of elongated associates with stack-like building blocks, as shown in molecular dynamics simulations of the aqueous solution with the concentration above critical micelle concentration. Our quantitative evaluation of the hydrophilicity switching in spiropyran/merocyanine containing surfactants may prompt the search for new systems, including colloidal and polymeric ones, aiming at remote tuning of their morphology, which could give new promising shapes and patterns for the needs of modern nanotechnology.

As one of GEO-constellation for environmental monitoring in the next decade, Geostationary Environment Monitoring Spectrometer (GEMS) is designed to observe the Asia Pacific region to provide the information on the atmospheric chemicals, aerosol and cloud properties. For the continuous monitoring of the sensor performance after its launch in early 2020, here we suggest deep convective clouds (DCCs) as a possible target for the vicarious calibration of GEMS, the first UV/VIS hyperspectral sensor onboard a geostationary satellite. Tropospheric Monitoring Instrument (TROPOMI) and Ozone Monitoring Instrument (OMI) are used as a proxy of GEMS, and a conventional DCC detection approach applying the thermal threshold test is used for the DCC detection based on the collocations with Advance Himawari-8 Imager (AHI) onboard Himawari-8 geostationary satellite. DCCs are frequently detected over the GEMS observation area on average over 200 pixels in a single observation scene. Considering the spatial resolution of GEMS, 3.5 km×7 km which is similar to TROPOMI, and its temporal resolution (8 times a day), availability of DCCs for vicarious calibration of GEMS is expected to be sufficient. Inspection of the DCC reflectivity spectra estimated from the OMI and TROPOMI data also shows a promising result. Even though, their observation geometry and sensor characteristics are quite a different, the estimated DCC spectra agree quite a well within a known uncertainty range with comparable spectral features. When the DCC detection is further improved by applying both visible and infrared tests, the variability of DCC reflectivity from the TROPOMI data is reduced by half, from 10% to 5%. This is mainly due to the efficient screening of cold thin cirrus with the visible test and of bright warm clouds with the infrared test. The precise DCC detection is also expected to contribute to the accurate characterization of the cloud reflectivity, which will be further investigated.

Target detection of defense technology is being rapidly upgraded with modern surveillance technologies. The latest techniques of surveillance are already being implemented for defense applications. Self-protection and hiding from opposing forces are the key principle for protection of special team in defense. Camouflage textiles aims to create confusing objects for target detection of military personnel. These textiles are applied for military protection such as clothing, weapon, vehicle and location hiding nets/tents, etc. The urgent need of camouflage textiles have been formulated with a technical solution and implementation of right camouflage materials for concealment of defense target signature against dry leaves, green leaves, tree bark-woodland combat background; water-marine combat background; sand-desertland combat background; stone-stoneland combat background; snow-snowland combat background; sky combat background and ice-iceland combat background, concrete-concreteland combat background (DGTWSICB) in ultraviolet-visible-infrared (UV-Vis-IR) spectrums. This hypothesis of optical & surveillance engineering has been coalesced for advancement of UV-Vis-IR-DGTWSICB camouflage textiles technology. The principle of camouflage engineering has been approached by broader spectrum probe in UV-Vis-IR rather than Vis ranges only. Furthermore, single formulation of camouflage textiles has been proposed for multidimensional CBs-DGTWSICB. Electromagnetic spectrum, reflection, electron energy, photonic signal and imaging mechanism in UV-Vis-IR have been presented for optical engineering of concealment, detection, recognition and identification of target signature against DGTWSICB. Spectrum relationship of camouflage materials and DGTWSICB materials have been illustrated and compared in UV-Vis-IR spectrums. Camouflage material design, method design & spectral design; adaptive camouflage; techniques for camouflage textile assessment for digital camera and hyperspectral camera imaging; image processing techniques and a hierarchical model have been demonstrated for augmentation of camouflage textiles in UV-Vis-IR illumination. Therefore, anticipated design of camouflage textiles may enhance high-performance innovation for modern surveillance of military protection related to digital camera, hyperspectral camera and radar. This hypothesis includes advance guideline for camouflage textiles design for CBs-DGTWSICB.

The drug delivery systems receive more and more attention for the control and treatment of many diseases due to their increased number in recent years. The main aims of this study were to develop and to characterize a polyurethane drug delivery system that it is intended to be used for the transmembrane transport of nucleosides. Three different samples have been synthesized based on aliphatic diisocyanates (hexamethylene diisocyanate, isophorone diisocyanate and lysine diisocyanate) as organic phase, respectively a mixture of polyethylene glycol, polycaprolactone diol and low molecular weight diols as aqueous phase. The samples were characterized by pH, refractivity index and solubility measurements, drug loading efficacy and release investigations, thermal behavior, Zetasizer, cells viability and irritation tests on mice skin. The results indicate the obtaining of different populations of neutral acido-basic particles with size between 132 and 190 nm; the Zeta potential values and SEM images show a medium tendency to form clusters, while UV-Vis evaluations indicate an almost 70% encapsulation efficacy, a prolonged release (45% of encapsulated substance is released in the first 5 days) and around 70% of particles have penetrated an artificial membrane in the first 24h. The synthesized products can be tested in further clinical trials, the currently tests on cells culture and mice skin revealing no side effects.

The self-organization properties of C70 fullerene molecules in a xylene/tetrahydrofuran binary mixture were studied for the first time by optical absorption, refractometry, and dynamic light scattering. A correlation has been established between the change in the refractive index of the C70/xylene/tetrahydrofuran solution and the degree of self-organization of C70 molecules in the medium at various concentrations and storage periods of the solution. It is shown that the features of the optical absorption spectrum of C70/xylene/tetrahydrofuran at a fixed low concentration of the fullerene are sensitive to its storage time. It was determined that the beginning time of the formation of C70 nanoclusters and their final size depend on the concentration of fullerene and the time of keeping the solution. The observed nature of the C70 fullerene solution in a binary mixture may help to elucidate the mechanism of self-organization in the future.

Using optical characterization, it is evident that the spin state of the spin crossover molecular complex [Fe{H2B(pz)2}2(bipy)] (pz = tris (pyrazol-1-1y)-borohydride, bipy = 2,2’-bipyridine) depends on the ferroelectric polarization of an adjacent thin film of the polymer ferroelectric polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP). The UV-Vis spectroscopy reveals that room temperature switching of [Fe{H2B(pz)2}2(bipy)] molecules in bilayers of PVDF-HFP/[Fe{H2B(pz)2}2(bipy)] as a function of ferroelectric polar polarization. The electric polarity dependence of bilayers of PVDF-HFP/[Fe{H2B(pz)2}2(bipy)] shows a strong dependence on the thickness of the PVDF-HFP layer. The PVDF-HFP/[Fe{H2B(pz)2}2(bipy)] interface may affect polarization retention in the PVDF-HFP thin film limit.

Chymotrypsin is an important proteolytic enzyme in human digestion system that cleaves milk proteins, through hydrolysis reaction, which makes it interesting subject to study activity of milk proteases. In this work, we compared detection of chymotrypsin by spectrophotometric, dynamic light scattering (DLS) and quartz crystal microbalance (QCM) methods and determined the limit of chymotrypsin detection (LOD), 0.15 ± 0.01 nM for spectrophotometric, 0.67 ± 0.05 nM for DLS and 1.40 ± 0.30 nM for QCM methods, respectively. We discuss peculiarities and give perspective for implementation of detection methods and note that while the optical detection methods are simple to implement, the QCM method is more robust for sample preparation. We give an overview on methods and instruments for detection of chymotrypsin and other milk proteases.

Today, more than 70 million tons of lignin are produced by the pulp and paper industry every year. However, the utilization of lignin as a source for chemical synthesis is still limited due to the complex and heterogeneous lignin structure. The purpose of this study was a selective photodegradation of industrially available kraft lignin in order to obtain appropriate fragments and building block chemicals for further utilization, e.g. polymerization. Thus, kraft lignin obtained from soft wood black liquor by acidification was dissolved in sodium hydroxide and irradiated at a wavelength of 254 nm with and without the presence of titanium dioxide in various concentrations. Analyses of the irradiated products via SEC showed decreasing molar masses and decreasing polydispersity indices over time. At the end of the irradiation period the lignin was depolymerised to form fragments as small as the lignin monomers. TOC analyses showed minimal mineralisation due to the depolymerisation process.

Addressing within field spatial variability for nitrogen management to avoid over and under-use of nitrogen is crucial for optimizing crop productivity and ensuring environmental sustainability. In this study we investigated the economic, environmental and agronomic benefits of variable rate nitrogen application in potato (Solanum tuberosum). An online visible and near infrared (vis-NIR) spectroscopy sensor we utilized to predict soil moisture content (MC), pH, total organic carbon (TOC), extractable phosphorus (P), potassium (K), magnesium (Mg), and cation exchange capacity (CEC) using a partial least squares regression (PLSR) models. The crop's normalized difference vegetation Index (NDVI) from Sentinel-2 satellite images was incorporated to online measured soil data to derive fertility management zones (MZs) maps, after homogenous raster and clustering analyses. The MZs maps were categorized into high fertile (VR-H), medium-high fertile (VR-MH), medium-low fertile (VR-ML), and low fertile (VR-L) zones. A parallel strip experiment compared variable rate nitrogen (VR-N) with uniform rate (UR) treatments, adjusting nitrogen levels based on fertility zones as: 50% less for VR-H, 25% less for VR-MH, 25% more for VR-ML, and 50% more for VR-L zones compared to the UR treatment. Results showed that the VR-H zone received a 50% reduction in N fertilizer input and demonstrated a significantly higher crop yield compared to the UR treatment. This implies a potential reduction in negative environmental impact by lowering fertilizer costs while maintaining robust crop yields. In total, the VR -N treatment received an additional 1.2 Kg/ha of nitrogen input, resulting in a crop yield increase of 1.89 tons/ha. The relative gross margin for the VR-N treatment compared to the UR treatment 374.83 €/ha, indicating substantial profitability for the farmer. To further optimize environmental benefits and profitability, additional research is needed to explore site-specific application of all farm resources through precision agricultural technologies.

The purpose of this investigation was to prepare a water-soluble complex by encapsulation of propolis extract with the carrier 2-hydroxypropyl-β-cyclodextrin (HP-β-CD) and to examine the influence of in vitro simulated gastrointestinal digestion (GID) on the content of the main polyphenolic groups when administered as aqueous suspension. The research was conducted on two continental samples of propolis from Croatia and a mixture of selected polyphenol standards. By applying UAE followed by a lyophilization procedure, it was possible to obtain a powder with a high content of polyphenols. The content of total phenols (TPs), total flavonols/flavones (TFFs) and total flavanones/dihydroflavonols (TFDs) in the fractions of oral and gastric phase and small intestinal phase performed with two models: centrifugation and dialysis through a semi-permeable membrane, was determined by three UV/Vis spectrophotometric methods: Folin-Ciocalteu, aluminium complexation and 2,4-dinitrophenylhydrazine method. The obtained results for both propolis complexes showed stability in the polyphenol content and high bioaccessibility during all three phases of digestion. The bioaccessibility of TPs, TFFs and TFDs under in vitro conditions after dialysis through a semipermeable membrane was lower compared to the intestinal phase model with centrifugation.

This work shows a correlation between light reflectance, absorption, and morphologies of series of (1-x) BM–x PT, (x = 0.0, 0.02, 0.04, 0.08, 0.12, 0.16, 0.24) ceramics composite. The (1-x) BM–x PT showed features of a black mirror with a low optical energy gap. The measured Vis-NIR diffused reflectance enabled the calculation of the energy gap using the modified Kubelka-Munk function. The estimated energy gap was lower than 1.5 eV related to low reflectance in the Vis-NIR range. Moreover, obtained histograms of grains, using scanning electron microscope, enabled the correlation between grains size and amount of lead titanate. We deduced from the ceramics surface morphology that marked porosity also induced reflectivity of low magnitude. We correlated the magnitude of the energy gap with phases of the BM-PT composite and with the electrical conductivity activation energy reported in the literature. Our results findings opened prospect studied materials for optical applications.

A new strategy to nanoengineer gold/fluorocarbon multilayer (ML) nanostructures is reported. We have investigated the morphological changes occuring at the metal-polymer interface in multilayer structures with varying volume fraction of gold (Au) and the kinetic growth aspect of the microscale properties of nano-sized Au in plasma polymer fluorocarbon (PPFC). Investigations were carried out at various temperatures and annealing time by means of grazing incidence small-angle and wide-angle X-ray scattering (GISAXS and GIWAXS). We have fabricated a series of multilayers with variying volume fraction (0.12, 0.27, 0.38) of Au and bilayer periodicity in ML structure. They show an interesting granular structure consisting of nearly spherical shaped nanoparticles within the polymer layer. The nanoparticle (NP) morphology changes due to the collective effects of NPs diffusion within ensembles in the in-plane vicinity and inter-layer with increasing temperature. The in-plane NPs size distinctly increases (from 1.9 to 4 nm) with increasing temperature. The NPs become more spherical thus reducing the surface energy. Linear growth of NPs with temperature and time shows diffusion-controled growth of NPs in the ML structure. The structural stability of the multilayer is controlled by the volume ratio of the metal in polymer. At room temperature UV-Vis shows a blueshift of the plasmon peak from 560 nm in ML Au/PTFE_1 to 437 nm in Au/PTFE_3. We have identified the fabrication and post-deposition annealing conditions to limit the Local Surface Plasmon resonance (LSPR) shift (from 〖∆λ〗_LSPR=180 nm (Au/PTFE_1) to 〖∆λ〗_LSPR=67 nm (Au/PTFE_3 ML)) and their optical response over a wide visible wavelength range. A variation in the dielectric constant of the polymer in precence of varying Au inclusion is found to be the main factor affecting the LSPR frequency. Our finding may provide insights in Nano engineering ML structure can be useful to systematically control the growth of NPs in polymer matrix.

In the literature, the chemical composition of Rhododendron tomentosum is mainly represented by the study of isoprenoid compounds of essential oil. In contrast, the study of the content of flavonoids will contribute to the expansion of the pharmacological action and the use of the medicinal plant for medical purposes. The paper deals with the technology of extracts from Rhododendron tomentosum shoots using ethanol of various concentrations and purified water as an extractant. Extracts from Rhododendron tomentosum were obtained by a modified method that combined the effects of ultrasound and temperature to maximize the extraction of biologically active substances from the raw material. By the method of high-performance thin-layer chromatography in the system of solvents ethyl acetate: formic acid: water (15:1:1) the following substances have been separated and identified: rutin, hyperoside, quercetin, and chlorogenic acid in all the extracts obtained. To quantify the total flavonoids content, a method of spectrophotometric determination based on the reaction of complexation with aluminum chloride has been developed. It has been proved that the course of the complexation reaction and, accordingly, the quantification of the flavonoid structure substances by the spectrophotometric method is influenced by some factors, including the environment, pH, the structure of the complexes, etc. Regardless of the chosen method, for the further production of Rhododendron tomentosum extracts with a higher content of flavonoid structure substance, it is advisable to use 60%, 70%, and 80% ethyl alcohol as extractant.

A Pt(II) complex featuring chelating tridentate bis-aryloxide tetrahydropyrimidinium based N-heterocyclic carbene (NHC) was synthesized and characterized by using different techniques. The electrochemical properties of the complex were investigated by cyclic voltammetry as well as differential pulse voltammetry, which revealed two reversible one-electron oxidation processes. The chemical generation and isolation of one-electron-oxidized species were performed oxidizing the initial complex by means of AgBF4. The combined UV-Vis/NIR- and EPR-spectroscopy studies supported by density functional theory (DFT) calculations suggest the formation of Pt(II)-phenoxyl radical complex. The latter open-shell derivative was structurally characterized by means of X-ray diffraction analysis. Finally, the neutral platinum complex was tested as a mediator in the process of electrocatalytic oxidation of 2-(methylamino)ethanol (MEA).

The electrical and optical properties of sol-gel derived aluminum-doped0 zinc oxide thin films containing 2 at.% Al were investigated considering the modifying effects of 1) increasing the sol H₂O content; and 2) thermal treatment procedure with high-temperature approach followed by an additional heat-treatment step under a reducing atmosphere. According to the results obtained via the TG-DTA analysis, FT-IR spectroscopy, X-ray diffraction technique and four-point probe resistivity measurement, it is argued that the sol hydrolysis, decomposition of the deposited gel and crystallization of grains result in grains of larger crystallite size and stronger c-axis preferred orientation with slightly less microstrain in the modified sample. The consequent morphology and grain-boundary characteristics turn out as improved conductivity, implying higher values of concentration and mobility of charge carriers. A detailed investigation on samples optical properties, in terms of analyzing their absorption and dispersion behaviors through the UV-Vis-NIR spectroscopy, support our reasoning for the increase of the mobility, and to a lesser extent, the concentration of charge carriers, while causing only a slight degradation of optical transmission. Hence, an enhanced performance as a transparent conducting film is claimed for the modified sample by comparing the figure-of-merit values.

The extensive use of engineered nanoparticles (ENPs) such as zinc oxide nanoparticles (ZnO NPs) in various commercial fields has spurred significant concern about its possible toxicological effects of ZnO NPs on human health and eco-system. Therefore, it is substantial to understand the aggregation phenomena which could attenuate this effect. This data article provides information on aggregation of ZnO NPs under the influence of various parameters of water chemistry. Moreover, Taguchi orthogonal array L27(313) design matrix was used to evaluate the effect of multiple parameters in aqueous solution. The data were obtained from single beam UV-Vis spectrophotometer (Optizen 2120 UV, Mecasys, Korea) using Optizenview 4.2.5 PC interference software, Fourier transform infrared spectrometer (FT/IR-4700, spectroscopy, JASCO Analytical Instruments, Easton, USA) and particle electrophoresis (NanoZS, Zetasizer, Malvern Instruments Ltd, Worcestershire, UK). The dataset draws attention on dominant parameters influencing aggregation of ZnO NPs in water. The analysis of variance (ANOVA) data revealed that electrolyte concentration, type and natural organic matter (NOM) concentration were the most significant parameters. Furthermore, FT-IR data presents a possible mechanism of ZnO NPs stabilization in the presence of different NOM. This data will be helpful for the development of environmental risk assessment strategies and prediction of fate and mobility of other ENPs in the aquatic environment.

Traditional soil characterization methods are time consuming, laborious and invasive and do not allow long-term repeatability of measurements. The overall aim of this paper was to assess and model spatial variability of the soil in an olive grove in south Italy by using data from two sensors of different type: a multi-spectral on-board drone radiometer and a hyperspectral visible-near infrared-shortwave infrared (VIS-NIR-SWIR) reflectance radiometer as well as sample data, to arrive at a delineation of homogeneous areas. The hyperspectral data were processed using continuum removal methodology to obtain information about the content and composition of clay. Differently, the multispectral data were firstly upscaled to the support of soil data using geostatistics and taking into account change of support. Secondly, the two-sensor data were integrated with soil granulometric properties by using the multivariate geostatistical techniques of multi-collocated cokriging and factor cokriging, in order to achieve a more exhaustive and finer-scale soil characterisation. The paper shows the impact of change of support on the uncertainty of soil prediction that can have a significant effect on decision making in Precision Agriculture. Moreover, four regionalised factors at two different scales (two per each scale) were retained and mapped. Each factor provided a different delineation of the field with areas characterised by different granulometry and clay composition. The applied method is sufficiently flexible and could be applied to any number and type of sensors.

MoS₂/TiO₂ nanostructures made of MoS₂ nanoparticles covering TiO₂ nanosheets have been synthesized, either via ex-situ or in-situ approaches. Morphology and structure of MoS₂/TiO₂ hybrid nanostructures have been investigated and imaged by means of X-ray diffraction (XRD) analysis and high-resolution transmission electron microscopy (HRTEM), while the vibrational and the optical properties have been investigated by Raman, Fourier-transform infrared spectroscopy (FTIR) and UV−visible (UV-Vis) techniques. The different stacking degrees together with the size distribution of the MoS₂ nanosheets, decorating the TiO₂ nanosheets, have been carefully obtained from HRTEM images. The nature of the surface sites on the main exposed faces of both materials has been detected by means of in-situ FTIR spectra of adsorbed CO probe molecule. The results coming from the ex-situ and in-situ approaches will be compared, by highlighting the role of the synthesis processes in affecting morphology and structure of MoS₂ nanosheets, including their curvature, surface defects, and stacking order. Some more, it will be shown that the in-situ approach is affecting the reactivity of the TiO₂ nanosheets too, hence in turn affects the MoS₂/TiO₂ nanosheets interaction.

This paper discusses a cross-disciplinary, international collaboration aimed at researching a series of 15th century choir books at the abbey of San Giorgio Maggiore on the homonymous island in Venice. Produced for the abbey itself, the books have never left the island during their 500-years history, thereby allowing a unique opportunity to analyse historic artefacts, which have undergone little modification over time. Prompted by ongoing cataloguing work on the manuscripts, a week-long analytical campaign using a combination of non-invasive analytical methods used in portable configuration allowed the comprehensive characterisation of ten volumes. The manuscripts’ palette and painting techniques were analysed using near-infrared imaging, reflectance spectroscopy in the UV-vis-NIR range, Raman spectroscopy, X-ray fluorescence mapping and digital microscopy. The paper will discuss the challenges linked to the fragility and the large dimensions of the volumes as well as the most interesting results of the investigation. These include the detection of unusual painting materials such as bismuth ink, as well as the discovery of a less homogeneous palette than originally expected, which prompted a partial revision of the attribution of the decoration in one of the volumes to a single artist.

In the present research, groups of nanolayered structures and nanohybrids based on organic green dyes and inorganic species are designated to act as fillers for PVA for inducing new optical sites and increasing its thermal stability through producing polymeric nanocomposites. In this trend, different percentages of Naphthol green B were intercalated as pillars inside the Zn-Al nanolayered structures to form green organic-inorganic nanohybrids. The two-dimensional green nanohybrids were identified by X-ray diffraction, TEM and SEM. According to the thermal analyses, the nanohybrid, which has the highest amount of green dyes, was used for modifying the PVA through two series. In the first series, three nanocomposites were prepared depending on the green nanohybrid as prepared. In the second series, the yellow nanohybrid, which was produced from the green nanohybrid by thermal treatment, was used to produce another three nanocomposites. The optical properties revealed that the polymeric nanocomposites depending on green nanohybrids became optical-active in UV and visible regions because the energy band gap decreased to be 2.2 eV. In addition, the energy band gap of the nanocomposites depended on yellow nanohybrids was 2.5 eV. The thermal analyses indicated that the polymeric nanocomposites are thermally more stable than that of the original PVA. Finally, the dual functionality of organic-inorganic nanohybrids that produced from the confinement of organic dyes and the thermal stability of inorganic species converted the non-optical PVA to optical-active polymer in a wide range with high thermal stability

Copper(II), nickel(II) and zinc(II) complexes of various peptide fragments of tau protein were studied by potentiometric and spectroscopic techniques. All peptides contained one histidyl residue and represented the sequences of tau(91-97) (Ac-AQPHTEI-NH2), tau(385-390) (Ac-KTDHGA-NH2) and tau(404-409) (Ac-SPRHLS-NH2). Imidazole-N donors of histidine were the primary metal binding sites for all peptides and all metal ions but in case of copper(II) and nickel(II) the deprotonated amide groups were also involved in metal binding by increasing pH. The most stable complexes were formed with copper(II) ion but the presence of prolyl residues resulted in significant changes in the thermodynamic stability and speciation of the systems. It was also demonstrated that nickel(II) and especially zinc(II) complexes have relative low thermodynamic stability with these peptides. Copper(II) catalyzed oxidation of the peptides was also studied. In the presence of H2O2 the fragmentation of peptides can be detected in all cases. In the simultaneous presence of of H2O2 and ascorbic acid the extent of the fragmentation of the peptide is less preferred, and the formation of 2-oxo-histidine also occurs.