Analysis Of Absorption Spectra Research Articles

Analysis of the high resolution absorption spectrum of ethylene between 5800 and 6400 cm−1

The highly congested room temperature absorption spectrum of ethylene (C2H4) is analyzed in the range 5800–6400 cm−1 on the basis of a previously elaborated empirical list of more than 12,200 lines. The investigated spectral interval coincides to a region of weak absorption of water, methane and acetylene. Quantitative information on the relatively strong C2H4 absorption in the region is valuable for trace detection applications.Relying on the position and intensity agreement with a line list of 12C2H4 transitions calculated by the variational method, 1674 transitions could be assigned to five bands (ν5+ν9, ν5+ν11, ν2+ν3 +ν11, ν2+ν6+ν9 and ν1+ν11). All the reported assignments are confirmed by Lower State Combination Difference (LSCD) relations i.e. all the upper states (607 in total) have coinciding determinations of their energies through several transitions (up to 6). The position and intensity comparisons between experiment and theory are discussed together with a comparison to previous works in the region.

Selective adsorption analysis of BAPTA depressants on the surface of carbonate minerals: Insights into flotation behavior and adsorption mechanism

Flotation separation of magnesite and calcite, two carbonate minerals, poses a significant challenge due to their intrinsic surface similarities. In this study, 1,2-bis(o-aminophenoxy)ethane-N,N,N′,N′-tetraacetic acid (BAPTA) was employed as a depressant to selectively regulate the mineral surface property in magnesite-calcite flotation. Micro-flotation experiments demonstrated that successful separation of magnesite-calcite mixtures could be achieved with 40 mg/L BAPTA and 100 mg/L sodium oleate (NaOL). Contact angle measurements and Ultraviolet-Visible absorption spectrum analysis revealed that pre-adsorption of BAPTA selectively hindered the adsorption of sodium oleate onto calcite surface, effectively eliminating the surface hydrophobicity of calcite induced by sodium oleate. The Extended-Derjaguin-Landau-Verwey-Overbeek (EDLVO) theory further indicated a reduced attractive interaction energy between magnesite and calcite particles in the presence of BAPTA. X-ray photoelectron spectroscopy (XPS) and density functional theory (DFT) simulation elucidated the stronger binding affinity of BAPTA towards calcium ions. Finally, a model was established for the selective formation of cage-like chelating structures on the calcite surface by BAPTA.

In silico study of inhibition activity of boceprevir drug against 2019-nCoV main protease.

Boceprevir drug is a ketoamide serine protease inhibitor with a linear peptidomimetic structure that exhibits inhibition activity against 2019-nCoV main protease. This paper reports electronic properties of boceprevir and its molecular docking as well as molecular dynamics simulation analysis with protein receptor. For this, the equilibrium structure of boceprevir has been obtained by DFT at B3LYP and ωB97XD levels with 6-311+G(d,p) basis set in gas and water mediums. HOMO-LUMO and absorption spectrum analysis have been used to evaluate the boceprevir's toxicity and photosensitivity, respectively. Molecular docking simulation has been performed to test the binding affinity of boceprevir with 2019-nCoV MPRO; which rendered a variety of desirable binding locations between the ligand and target protein's residue positions. The optimum binding location has been considered for molecular dynamics simulation. The findings have been addressed to clarify the boceprevir drug efficacy against the 2019-nCoV MPRO.

Low-cost and highly sensitive colorimetric and visual detection of amikacin in milk using melamine functionalized gold nanoparticles.

This study developed a rapid, low-cost and highly sensitive analytical method using melamine functionalized gold nanoparticles (MA-Au NPs) as a colorimetric sensor to detect amikacin in milk. The MA-Au NPs were synthesized using a self-assembly process and analyzed using absorption spectroscopy, transmission electron microscopy (TEM), and Fourier transform infrared (FT-IR) spectroscopy. The MA-Au NPs exhibited a distinct surface plasmon resonance (SPR) absorption peak at 520 nm and demonstrated excellent spherical dispersion. The reaction parameters were optimized, with a Au NP concentration of 2.0 × 10-7 mol L-1, MA concentration of 1.0 × 10-6 mol L-1, pH of 4.0, and reaction time of 15 minutes. In the optimization experiment, the effects of unmodified Au NPs and MA-Au NPs as colorimetric sensors for amikacin determination were compared. As a specific amount of amikacin was added to the Au NP solution, the reaction solution showed a visible change from wine red to purple and then to blue gray; a red-shift in the absorption spectrum of the solutions was observed, which could also be analyzed using the A640/A520 value, and the color changes were recorded using smartphones for visual detection through RGB (red-green-blue) data image analysis, which made the detection easy and fast. As a result, two approaches were devised using visible absorption spectra and smartphones. A linear correlation was established between the A640/A520 value and the concentration of amikacin in the range of 4.0 to 16.0 × 10-8 mol L-1. The minimal limit of detection (LOD) for absorption spectrum analysis was 3.75 × 10-9 mol L-1, whereas for smartphone analysis, it was 6.0 × 10-8 mol L-1. The recoveries ranged from 103.09% to 104.51%, while the relative standard deviations (RSDs) ranged from 3.76% to 4.25%. The proposed method was used to detect actual milk samples. The results showed that the method is simple, selective, and practical.

Gas-liquid contact evaporation of concentrate leachate from disk-tube reverse osmosis treatment in waste incineration plant

In order to utilize waste heat such as exhaust steam and hot air passing through air preheater in the waste incineration plant to heat air used for evaporating leachate concentrate (LC) by gas-liquid contact evaporation technology, hot air of 600 °C, 450 °C and 250 °C was used to evaporate LC in a laboratory-scale evaporator to obtain purified condensate used for supplying water for circulating cooling water system. The influence of pH, hot air temperature and evaporation rate on COD and NH3–N in condensate were investigated to identify the optimum operation of this technology. The results showed that COD concentration in condensate obviously decreased with increase in hot air temperature. Higher hot air temperature led to higher initial evaporation temperature, and evaporation rate of water was significantly greater than that of small molecular organic matter with lower boiling point than water with increasing hot air temperature. Reduction in contents of phenol, ketone and benzene was responsible for COD decreasing in condensate. COD in condensate decreased with increase in pH, as the amount of volatile organic matter such as fatty acids escaped from LC to condensate decreased. The pH had little influence on the DOM in condensate according to EEM spectra analysis. Evaporation rate had little influence on COD in the condensate water. NH3–N concentrations in condensate in all experimental groups were far away from the limit value (10 mg/L) in the water quality standard. Under the premise of meeting water quality standard, the lowest temperature (450 °C) of hot air was selected to save energy and use lower grade waste heat. Therefore, the optimum condition was 450 °C of hot air, pH = 7 of LC and CF = 10. At this condition, molecular weight of DOM in the condensate was smaller and humification degree and aromaticity of DOM were lower according to UV–visible absorption spectrum analysis.

Exploration of 4-Chloro-3-nitrocoumarin: Spectroscopic Analysis, DFT Insights, Molecular Docking, Assessments of Antibacterial and In Vitro Anticancer Activities as a Potent Bioactive Agent

The detailed theoretical and experimental (FT-IR, FT-Raman, UV-visible) spectroscopy analyses of the 4-Chloro-3-nitrocoumarin (CNC) molecule were carried out. The CNC compound's pharmacological properties were also investigated utilizing antibacterial and anticancer activity investigations. Initially, the CNC molecule was optimized by the density functional theory B3LYP method with a cc-pVTZ basis set using the Gaussian 09W program. The optimized molecular structure provides the harmonic vibrational frequencies of the CNC molecule. The observed and computed vibrational wavenumbers were assigned and found to be well correlated. UV-Vis absorption spectrum analysis indicates that the molecule contains π→π* electronic transition. Frontier molecular orbitals (FMOs) analysis indicates that the LUMO of CNC molecule is mainly located over the nitro group, it indicates that the nitro group is particularly prone to accepting electrons from other molecules and participate in chemical reactions where acts as an electrophile. Mulliken atomic charge distribution analysis further confirms the FMOs results. The antibacterial test results validate that the CNC molecule exhibits a stronger inhibitory effect on Staphylococcus aureus compared to the other tested bacteria. In vitro anticancer cytotoxicity analysis clearly evidences that the CNC compound inhibits the growth of HeLa cervical cancer cell lines more than A549 lung cancer cell lines. In silico molecular docking study further validates that the CNC molecule inhibits the function of the p38a Mitogen-activated protein kinase 14, which has been associated with cervical cancer. As a result, the present study paves the way for the development of new drugs to treat cervical cancer.
 Keywords: 4-Chloro-3-nitrocoumarin; DFT; FT-IR; FT-Raman; Anticancer; Molecular docking; Cervical cancer drug.

Hydrothermal synthesis and characterization of nanostructured nickel vanadate for supercapacitor and photocatalytic applications

We successfully synthesised nickel vanadate (NiVO3) nanocomposite by an inexpensive hydrothermal technique. Several analytical methods have been employed to characterise the synthesised nanocomposite. The crystal structure of NiVO3 is orthorhombic, and its crystallite size is around 10.3 nm. The NiVO3 nanocomposite has an optical band gap of 2.62 eV from the absorption spectra analysis. At a current density of 5 Ag−1, the NiVO3 nanocomposite exhibits a specific capacitance value of 398 Fg−1 and a retention rate of almost 90% after 2000 cycles. Furthermore, stability studies show that at a current density of 5 Ag−1, 90% of the capacitance is retained for 4000 cycles. The photocatalytic studies to break down the industrial pollutant Fast Orange Red (F-OR) dye show a 98.7% decolourization rate after 120 min of exposure to UV light irradiation. These features promote the creation of such nanocomposites for practical energy and environmental applications while providing a deeper understanding of the material’s characteristics.

Pure-water-soluble colorimetric chemosensors for highly sensitive and rapid detection of hydrogen sulfide: Applications to evaluation of on-site water quality and real-time gas sensors

Hydrogen sulfide (H2S) has adverse effects on humans in various routes through water and air. However, the versatile detection of hydrogen sulfide (H2S) gas in various environments is still challenging. Herein, we report a highly sensitive, rapid, and selective colorimetric chemosensor (IID1) for the detection of H2S in diverse conditions including solution in pure water, thin-film, dyed-fabric, and coated silica in ambient air. The H2S-induced chemical reaction of IID1 results in significant spectral changes in UV-Vis absorption, accompanied by a discernible color change from dark red to colorless. Moreover, IID1 exhibits excellent selectivity among the competitive analytes, with a detection limit of 1.12 ppb and a rapid detection time (<10 s), which is among the highest performances reported for colorimetric H2S chemosensors. The detection mechanism is systemically investigated based on the analyses of UV-Vis absorption, NMR, and mass spectra. Utilizing the high solubility of IID1 in pure water, we successfully evaluate on-site water (river, lake, stream, reservoir, and tap water) quality with excellent accuracy. Furthermore, we demonstrate H2S detection on paper strips and face masks using the IID1. Our results suggest that IID1 is a practical sensor platform for the efficient detection of H2S in various environments.

The potentials of Si-doped magnesium oxide nanotubes for decontamination of pollutants

This work investigated the potential of the silicon-doped magnesium oxide nanotubes (Si: MgONT) to serve as a photocatalyst for the treatment of pollutants. The analysis of the photocatalytic properties of the Si: MgONT was carried out based on considering structural, electronic and optical properties at Si concentrations of 3.12% and 6.25%, respectively. We performed ground state analysis and ionic interactions using density functional theory (DFT) via quantum ESPRESSO and Yambo codes. The results of structural property analysis showed that pristine single-walled magnesium oxide nanotubes (SWMgONT) were stable to the introduction of Si impurities at a concentration of up to 6.25%. The highest binding energy value of −288.66 eV for 3.12% Si-doped SWMgONT showed that photons can be bound more strongly in this system than for 6.25% Si-doped and pure SWMgONT. 3.12% Si-doped SWMgONT exhibited indirect band gaps of 2.36 eV, which is well above the standard overpotential for pollutant degradation, while 6.25% SWMgONT had no bandgap. Analysis of the optical absorption spectra showed that 3.12% SWMgONT absorbs light very well in the visible region and reflects it in the IR region, while pristine and 6.25% MgONT showed poor light absorption in the visible region. On this basis, this work recommended 3.12% Si-doped SWMgONT semiconductor as a better material for dye degradation, CO2 reduction and hydrogen evolution.

Structural, mechanical, electronic and optical properties of Si decorated zinc oxide nanotube photocatalyst for hydrogen evolution via overall water splitting: A DFT study

This work investigated an Si-doped single-walled zinc oxide nanotube (SWZnONT) as photocatalyst for hydrogen energy production. Photocatalytic properties of the Si-doped SWZnONT were determined based on analysis of structural, electronic and optical absorption spectra using density functional theory. The obtained data for structural and mechanical properties of the systems revealed that Si-doped SWZnONT was stable under 2.7 % and 5.5 % of Si concentrations. Furthermore, the studied SWZnONT doped with 2.7 % Si demonstrated an indirect band gap of 2.6 eV which is desirable to be an ideal photocatalyst. Results from optical spectra analysis revealed that Photo-generated holes on the Si-doped SWZnONT surface promote water splitting.

Spectroscopic Characterization, Quantum Chemical, Molecular Docking, Antibacterial and Anticancer Studies on Ethyl Coumarin-3-Carboxylate: an Antibacterial and Lung Cancer Agent

The detailed theoretical and experimental (FT-IR, FT-Raman, UV-visible) spectroscopy analyses of the Ethyl Coumarin-3-Carboxylate (ECC) molecule were carried out. The ECC compound’s pharmacological properties were also investigated, utilizing antibacterial and anticancer activity investigations. Initially, the ECC molecule was optimized by the density functional theory B3LYP method with a 6-311 G++ (d,p) basis set using the Gaussian 09 W program. The optimized molecular structure provides the harmonic vibrational frequencies of the ECC molecule. The observed and computed vibrational wavenumbers were assigned and found to be well correlated. UV-Vis absorption spectrum analysis indicates that the molecule contains π →π* and n → π* electronic transitions. The Frontier molecular orbital analysis confirmed the molecular reactivity and bioactivity of ECC, while the Mulliken atomic charge distribution analysis pinpointed the molecule’s reactive sites. Antibacterial testing demonstrated the ECC compound’s inhibitory effect on various bacterial strains, with a particular impact on Klebsiella pneumonia. In vitro, anticancer assessments showcased ECC's stronger inhibitory effects on A549 lung cancer cell lines compared to HeLa cervical cancer cell lines. Additionally, in silico molecular docking investigations provided further validation that the ECC compound can inhibit the function of the epidermal growth factor receptor, a factor associated with lung cancer. As a result, this study lays the foundation for the development of novel drugs for lung cancer treatment.

Electronic structure, and dielectric, magnetic and reflection-loss behaviors of BaFe12-xMnxO19 (0 < x ≤ 2) hexaferrites

M−type hexaferrites doped with transition metals are important materials used widely in modern electronic devices. Although many research works considered their magnetic properties, the relation between their electronic structure and electromagnetic behaviors have been less taken into account, particularly Mn-doped M−type hexaferrites. This work presents a detailed study on the electronic structure, and dielectric, magnetic and reflection-loss behaviors of BaFe12-xMnxO19 (x = 0.5, 1 and 2) hexaferrite specimens prepared by conventional solid-state reactions. The analysis of X-ray absorption spectra proves a mixed oxidation state of Fe2+,3+ and Mn2+,3+ ions, and chemical shifts of Fe2+ → Fe3+ and Mn2+ → Mn3+ when x increases from 0.5 to 2. These factors change the unit-cell volume, and cause Mn3+-related Jahn-Teller distortions. Concurrently, the saturation magnetization Ms varies in the range from 24 to ∼31 emu/g, which is associated with interaction competitions between Fe2+,3+-Mn2+,3+ pairs and Fe2+-related spin canting. Having studied electromagnetic behaviors, we have found strong changes in values of the permittivity and permeability at frequencies f = 10∼15 GHz. For a thickness t = 2.4 mm, reflection-loss magnitudes of microwave are about 10 ∼ 11 dB (corresponding to above 90% microwave being absorbed), with an absorption bandwidth of ∼3 GHz. Assessments of the magnetic and dielectric loss tangents, and Cole-Cole curves indicate electrical energy dissipation associated with interfacial/dipolar polarizations and conductive loss playing a dominant role in microwave absorption of BaFe12-xMnxO19.

Analysis of an Ultra-Wideband, Perfectly Absorptive Fractal Absorber with a Central Square Nanopillar in a Cylindrical Structure with a Square Hollow

In this study, a fractal absorber was designed to enhance light absorptivity and improve the efficiency of converting solar energy into electricity for a range of solar energy technologies. The absorber consisted of multiple layers arranged from bottom to top, and the bottom layer was made of Ti metal, followed by a thin layer of MgF2 atop it. Above the two layers, a structure comprising square pillars formed by three layers of Ti/MgF2/Ti was formed. This pillar was encompassed by a square hollow with cylindrical structures made of Ti material on the exterior. The software utilized for this study was COMSOL Multiphysics® (version 6.0). This study contains an absorption spectrum analysis of the various components of the designed absorber system, confirming the notion that achieving ultra-wideband and perfect absorption resulted from the combination of the various components. A comprehensive analysis was also conducted on the width of the central square pillar, and the analysis results demonstrate the presence of several remarkable optical phenomena within the investigated structure, including propagating surface plasmon resonance, localized surface plasmon resonance, Fabry–Perot cavity resonance, and symmetric coupling plasma modes. The optimal model determined through this software demonstrated that broadband absorption in the range of 276 to 2668 nm, which was in the range of UV-B to near-infrared, exceeded 90.0%. The average absorption rate in the range of 276~2668 nm reached 0.965, with the highest achieving a perfect absorptivity of 99.9%. A comparison between absorption with and without outer cylindrical structures revealed that the resonance effects significantly enhanced absorption efficiency, as evidenced by a comparison of electric field distributions.

Investigation of sunlight driven SPR assisted photocatalytic activity of Ag doped SnO2 nanoparticles

Photocatalysis triggered by visible light has emerged as a viable method for addressing environmental pollution and the energy crisis in our society. Numerous metal oxide semiconductors are transformed into visible light active photocatalysts by adopting some straightforward methods. One such efficient way of creating a visible light active photocatalyst is doping a pure semiconductor with plasmonic metal nanoparticles. Our work thoroughly investigates the photocatalytic properties of pure SnO2 nanoparticles (NP) and SnO2 doped with 1%, 3%, and 5% ‘Ag’ under sunlight. These samples are prepared using a straightforward sol–gel approach, followed by a hydrothermal procedure. To examine the different properties and morphology of the synthesized samples, several analytical tools, including UV–visible spectrometer, XRD, XPS, TEM, PL spectrometer and FTIR are used. Analysis of UV-visible absorbance spectra shows a noticeable narrowing of the band gap with increased ‘Ag’ doping. XRD analysis confirms the tetragonal structure of all samples. Methyl orange (MO) dye is used as an imitation of an organic pollutant to examine the photocatalytic activity under sunlight. When compared to pure SnO2 NP, every ‘Ag’ doped SnO2 NP sample exhibits a considerable improvement in the photodegradation of methyl orange. Analysis of PL spectra of SnO2 NPs doped with ‘Ag’ suggests that the major causes of this enhancement in photocatalysis are surface defects and the surface plasmon resonance (SPR) effect caused by ‘Ag’ doping. The scavenging test claims that the holes are the primary and the superoxide radicals are the secondary reactive species which are responsible for MO degradation under sunlight.

Exploring the photophysical interaction of xanthene dyes with gold nanorods by optical spectroscopic techniques and in-vitro cytotoxicity studies of dye-nano conjugates

The current study investigates the photophysical interactions of xanthene dyes such as fluorescein (FL) and rose bengal (RB) dyes with cetyltrimethylammonium bromide stabilized gold nanorods (CTAB-AuNRs) using optical spectral techniques, and computational interaction analyses. When xanthene dyes are conjugated with CTAB-AuNRs, significant modifications in their optical spectroscopic characteristics are found. In the absorption spectrum analyses of dye-AuNRs systems, the appearance of longitudinal plasmon resonance bands and the hypochromic behavior of xanthene dyes were observed in response to the interaction of CTAB-AuNRs. The gathered extinction spectral results indicated that there were significant electrostatic interactions between the positively charged CTAB-AuNRs and the negatively charged xanthene dye molecules. At the same time, the substantial quenching with a reduced quantum yield of the dye molecules is shown in the emission spectra of xanthene dyes with CTAB-AuNRs. The strong electrostatic interactions and ground state complex between xanthene dyes and CTAB-AuNRs have been suggested as the mechanism of emission quenching. The results of the emission quenching are supported by the calculated high binding constant values. Additionally, the results of computational interaction investigations also demonstrate the near closeness of xanthene dye molecules and CTAB-AuNRs. Finally, the cytotoxicity of free dyes and dye-nanoconjugates was next tested against breast (MCF-7) and lung (A-549) cancer cells. All the tested samples exhibit significant antiproliferative activity against MCF-7 and A-549 cancer cells. These cytotoxic study results showed that cells treated with xanthene dyes were less sensitive than FL-AuNRs and RB-AuNRs dye nanoconjugates.

ANTHOCYANINS IN LILAC FLOWERS SYRINGA VULGARIS

Anthocyanins from flowers of common lilac (Syringa vulgaris L.) of various color intensities and shades of lilac color from nine samples purchased at the Belgorod market were studied using reverse-phase high-performance liquid chromatography. To determine the structure of anthocyanins, we used the analysis of electronic absorption spectra recorded in the cuvette of a diode array detector and the analysis of mass spectra obtained by electrospray ionization with partial fragmentation. As a result, it was found that in all the studied samples the main component was delphinidin-3-rutinoside (84–90% by peak areas in the chromatogram). The level of cyanidin-3-rutinoside biosynthesis was significantly lower (6–19.6%). Among the minor compounds, delphinidin-3-glucoside and petunidin-3-glucoside were found. Among the unusual compounds, pyranoanthocyanin, built on the basis of delphinidin-3-rutinoside due to condensation with pyruvic acid, was found in a number of studied samples, but the reasons for its appearance have not yet been established. The total content of anthocyanins is low and amounts to 0.020–0.120 g per 100 g of fresh material (depending on the color intensity of the original plant material) in terms of cyanidin-3-glucoside. By drying flowers on a cut branch, air-dried material was obtained containing 0.100–0.300 g per 100 g of anthocyanins.

Spectroscopic Identification of Bacteria Resistance to Antibiotics by Means of Absorption of Specific Biochemical Groups and Special Machine Learning Algorithm.

FTIR (Fourier transform infrared spectroscopy) is one analytical technique of the absorption of infrared radiation. FTIR can also be used as a tool to characterize profiles of biomolecules in bacterial cells, which can be useful in differentiating different bacteria. Considering that different bacterial species have different molecular compositions, it will then result in unique FTIR spectra for each species and even bacterial strains. Having this important tool, here, we have developed a methodology aimed at refining the analysis and classification of the FTIR absorption spectra obtained from samples of Staphylococcus aureus, with the implementation of machine learning algorithms. In the first stage, the system conforming to four specified species groups, Control, Amoxicillin induced (AMO), Gentamicin induced (GEN), and Erythromycin induced (ERY), was analyzed. Then, in the second stage, five hidden samples were identified and correctly classified as with/without resistance to induced antibiotics. The total analyses were performed in three windows, Carbohydrates, Fatty Acids, and Proteins, of five hundred spectra. The protocol for acquiring the spectral data from the antibiotic-resistant bacteria via FTIR spectroscopy developed by Soares et al. was implemented here due to demonstrating high accuracy and sensitivity. The present study focuses on the prediction of antibiotic-induced samples through the implementation of the hierarchical cluster analysis (HCA), principal component analysis (PCA) algorithm, and calculation of confusion matrices (CMs) applied to the FTIR absorption spectra data. The data analysis process developed here has the main objective of obtaining knowledge about the intrinsic behavior of S. aureus samples within the analysis regions of the FTIR absorption spectra. The results yielded values with 0.7 to 1 accuracy and high values of sensitivity and specificity for the species identification in the CM calculations. Such results provide important information on antibiotic resistance in samples of S. aureus bacteria for potential application in the detection of antibiotic resistance in clinical use.

Different look at S-p bonding orbital in CdS, with Zn and Se series gap investigations

The electronic characteristics of Cadmium sulfide (CdS) series Zn x Cd16−x S8Se8 and Cd16Se16−x S x are investigated. According to the calculations, barely 12% Zn (X = 2) in the form Zn2Cd14Se16 is required to maximize the gap. To properly evaluate the excited states, the generalized gradient approximation (GGA) and modified Becke-Johnson (mBJ) potentials are utilized in the computations. The parent compound CdS exhibits three distinct forms of crystal structures, with the hexagonal structure being remarkably stable under the GGA and mBJ functionals. The partial density of states around the Fermi level demonstrates that the system’s electronic characteristics are determined by the interaction of S-p and Cd-s,p states. A substantial splitting of the valence band, shown by band structure analysis, suggests a greater polarization crystal field in the hexagonal CdS structure. The stereochemical activity of the S atom stimulated the CdS compound for extremely tiny displacements of 0.0014 Å and 0.043 Å for the Cd and S atoms in the [001] direction, respectively, as well as tilting of the Cd-S-Cd link. This compound exhibits lone pair properties, with three valance electrons of the p-orbital participating in covalent bonding and S-s electrons fully occupied. Furthermore, Van Hove singularities are discovered in the electron density of states due to the Cd-d atoms that support in the analysis of optical absorption spectra. Finally, the results suggest that CdS has potential for solar cells applications due to its direct wide band gap semiconductor features,

Zinc protoporphyrin IX generation by Leuconostoc strains isolated from bulged pasteurized vacuum sliced hams

The colour of meat typically fades as it decays. However, it has been observed that certain vacuum-packaged spoiled hams can maintain a pink colour even when the packaging is bulged. A large amount of Zinc protoporphyrin IX (ZnPP) was found in these hams, compared to fresh red hams or spoiled and grey hams. Combined with high-throughput sequencing and cultural isolation, the potential cultures of Leuconostoc mesenteroides S-13 (LM), Leuconostoc citreum OCLC11 (LC), and Leuconostoc mesenteroides subsp. IMAU:80679 (LS) were selected based on their ability to produce ZnPP. Subsequently, these cultures were introduced into a fermented sausage model to assess their effect on colour conversion. The analysis of absorption and fluorescent spectra showed that Nitrite sausages contained nitrosyl heme pigment, while bacteria-inoculated sausages were predominantly composed of ZnPP. In addition, the a* value of the LS sausage was close to the Nitrite group at the end of fermentation, significantly higher than control, indicating the effect of bacterial metabolism on the redness. Meanwhile, the Ferrochelatase (FECH) activity of LM, LC and LS groups were 140 ± 13, 113 ± 16 and 201 ± 20 U/g sausage, respectively, providing a potential method on compensating for nitrite/nitrate substitution based on the presence of ZnPP in meat products.

Features of the management of the rule of Urbakh in ZnSe:Yb crystals

A comparative analysis of the edge absorption spectra measured in the temperature range of 290–470 K for two types of zinc selenide substrates has been carried out. It has been established that the self-absorption edge of pure ZnSe: Yb melt crystals is described by the «crystalline» approximation of the general Urbach rule, which is a consequence of dynamic disordering. In samples doped with ytterbium, at 330 K, a reversible transition from dynamic to static disordering was detected, which is described by the “glassy” approximation of the general Urbach rule.