Search

Coffee is one of the most popular non-alcoholic beverages, consumed as a raw material in different food sectors. The popularity of coffee is induced by its pleasant flavor, taste, and highly nutritious nature. However, the absorption of potentially toxic elements (PTEs) through preharvest, harvesting, and post-harvest stages makes it a potentially rich source. Essential elements are potentially toxic at a higher concentration than required for the human body to work. PTEs intake through food systems may lead to health risks, including mutagenicity, teratogenicity, carcinogenicity, and embryotoxic effects. Different analytical techniques such as spectroscopy, electromigration, and electrochemical. are used for PTEs content determination of coffee. Considering the importance of PTEs in human health and the worldwide popularity of coffee, their monitoring of coffee is crucial. Therefore, this study is aimed to investigate the classification, prevalence, and determination techniques of PTEs in different coffee types. [ABSTRACT FROM AUTHOR]

Geometric and electronic structures of molecular (AH), cationic , zwitterionic (A–H+), and anionic (A–) forms of substituted naphthalenesulfonic (1-aminonaphthalene-8-sulfonic and 1-(N-phenyl)aminonaphthalene-8-sulfonic) acids are considered by the B3LYP DFT method. The theoretical electronic absorption and emission spectra of various forms of the studied sulfonic acids are recorded and analyzed. It is shown on the example of the molecular form of 1-aminonaphthalene-8-sulfonic acid that the absorption bands of conformer I are shifted to the short-wavelength region due to the presence of intramolecular hydrogen bonding, in contrast to the conformers containing no such bonds. The relationship between the energy and shape of frontier orbitals of various forms of sulfonic acids and the features of their electronic absorption spectra is analyzed. It is shown that the theoretical emission spectra of the cationic and zwitterionic forms of 1-(N-phenyl)aminonaphthalene-8-sulfonic acid reproduce well the tendency of the experimental spectra where the band with the maximum wavelength shifts to the long-wavelength region upon the transition from an acidic medium to weakly acidic and neutral ones. [ABSTRACT FROM AUTHOR]

This study proposes the use of thiomalic acid--modified Au and Ag nanoparticle mixtures (TMA-Au/AgNP mixes) for the selective detection of tricyclazole. Upon the addition of tricyclazole, the color of TMA-Au/AgNP mixes solution changes from orange-red to lavender (red-shift). According to the density-functional theory calculations, tricyclazole-induced aggregation of TMA-Au/AgNP mixes through electron donor--acceptor interactions was proved. The sensitivity and selectivity of the proposed method are affected by the amount of TMA, volume ratio of TMA-AuNPs to TMA-AgNPs, pH value, and buffer concentration. The ratio of absorbance (A654/A520) of TMA-Au/AgNP mixes solution is proportional to the concentration of tricyclazole over the range 0.1--0.5 ppm with a linear correlation (R² = 0.948). Moreover, the limit of detection was estimated at 0.028 ppm. The practicality of TMA-Au/AgNP mixes was validated for the determination of tricyclazole concentration in real samples (spiked recovery was 97.5%--105.2%), demonstrating its advantages of simplicity, selectivity, and sensitivity. [ABSTRACT FROM AUTHOR]

Objective: This investigation evaluated the effect of two sintering modes of a translucent zirconia (Y‐TZP) on its surface roughness, topography, phase‐transformation (t → m), translucency and biaxial flexure fatigue strength. Materials and Methods: To do so, 50 Y‐TZP discs (Ø = 15 mm; thickness = 1.2 mm; IPS e.max ZirCAD LT) were prepared and divided into two groups: Standard mode (SM) and Fast mode (FM). Staircase fatigue testing was performed (piston‐on‐three balls set‐up, ISO 6872:2015), as well as surface roughness, profilometry, scanning electron microscopy (SEM‐FEG), energy dispersive X‐ray spectroscopy (EDX), phase transformation (t → m) using X‐ray diffraction analysis (XRD), translucency parameter analysis (TP and TP00) and fractography. Results: The results showed no statistical significant differences for roughness parameters (p > 0.05, SM: Ra = 0.13 ± 0.02, Rz = 1.21 ± 0.26 and RSm = 24.91 ± 2.19; FM: Ra = 0.14 ± 0.03, Rz = 1.32 ± 0.25 and RSm = 24.68 ± 2.16) or flexural fatigue strength (SM: 512 (464–560) MPa; FM: 542 (472–611) MPa) between the groups. In addition, similarity in surface morphological features (SEM and profilometry), composition and phases (EDX and XRD) was observed between the firing protocols. Fractography showed that the failure origin occurred on the tensile side. Sintering mode did not affect the TP (F = 0.001, p = 0.97) and TP00 (F = 0.12, p = 0.72). Conclusions: Therefore, the fast‐sintering mode is suggested as a viable alternative to the standard mode since it does not influence the evaluated surface morphology, microstructure, fatigue strength and translucency of a translucent monolithic zirconia. Clinical Significance: The fast sintering mode is a viable alternative for zirconia without compromising its topography, microstructure, mechanical performance or translucency. [ABSTRACT FROM AUTHOR]

Prof. Dr. Panne's ambition as an editor for ABC is to demonstrate that good analytical chemistry is at the core of many fundamental and applied scientific problems and innovations and will contribute to solving the grand challenges of our times. We continue to have a dynamic team of editors at ABC. [Extracted from the article]

The technological mineralogical characteristics of cesium-containing minerals in tailings were examined by means of chemical analysis, the energy spectrum analysis method, and MLA (mineral liberation analyzer) to determine the element content, phase analysis, associated mineral components, degree of liberation, particle size, etc. The results showed that the samples mainly contained spodumene, quartz, feldspar, mica, and other minerals. Pollucite was the main cesium-containing mineral in the sample, which had a cesium oxide content that was as high as 34.58%. The mineral content of pollucite in the sample was relatively low—only 1.23%. The pollucite monomer content and the amount of rich intergrowth was 85.25%, and the metal distribution of cesium in the +0.074 mm sample was as high as 87.06%. Spodumene was the main mineral associated with pollucite. The beneficiation evaluation of this tailing sample was conducted using a combined process that integrated desliming, magnetic separation, and froth flotation, and a pollucite concentrate containing 4.45% Cs2O was obtained with a 63.71 recovery rate. This indicates that little pollucite was removed by means of desliming and magnetic separation before froth flotation recovery, but during the froth flotation stage in spodumene and feldspar, a large pollucite loss was observed. Therefore, to improve pollucite recovery, a pollucite-specific adsorption reagent should be synthesized. [ABSTRACT FROM AUTHOR]

This article explores the influence and applications of Artificial Intelligence (AI) in analytical chemistry, highlighting its potential to revolutionize the analysis of complex data sets and the development of innovative analytical methods. Additionally, it discusses the role of AI in interpreting large-scale data and optimizing experimental processes. AI has been fundamental in managing heterogeneous data and in advanced analysis of complex spectra in areas such as spectroscopy and chromatography. The article also examines the historical development of AI in chemistry, its current challenges, including the interpretation of AI models and the integration of large volumes of data. Finally, it forecasts future trends and the potential impact of AI on analytical chemistry, emphasizing the need for ethical and secure approaches in the use of AI. [Display omitted] • AI revolutionizes data analysis in analytical chemistry. • Advanced AI aids complex spectroscopy and chromatography interpretation. • AI in chromatography enhances compound identification and quantification. • Machine learning predicts properties, enhancing drug and material discovery. • Explainable AI models improve interpretability in analytical chemistry. [ABSTRACT FROM AUTHOR]

Three new phenolic glycosides (1 – 3) and a new lignan glycoside (4), together with five known compounds (5 – 9) were isolated from the ethanol extract of the aerial part of Gaultheria leucocarpa var. yunnanensis (Franch.) T.Z.Hsu & R.C.Fang. Their structures were determined on the basis of spectroscopic techniques, experimental and calculated ECD spectra, acid hydrolysis, and enzymatic hydrolysis experiments. All the isolates were evaluated for their anti-inflammatory and antioxidant activities. Compounds 7 and 8 exhibited inhibitory effects against the LPS-induced production of NO with IC 50 of 63.71 and 10.66 μM, respectively, compared to L-NMMA having an IC 50 of 6.95 μM. Besides, compound 7 also represented significant DPPH radical scavenging activity with EC 50 of 18.75 μM, comparable with vitamin C (EC 50 = 15.77 μM). [Display omitted] • Four new (1 – 4) and five known (5 – 9) compounds were isolated from Gaultheria leucocarpa var. yunnanensis. • Compounds 7 and 8 exhibited moderate inhibition against LPS-induced NO production. • Compound 7 showed a comparable DPPH radical scavenging effect to vitamin C. [ABSTRACT FROM AUTHOR]

Novel Ce 2 (MoO 4) 2 (Mo 2 O 7) (CMO) ceramics were prepared by a conventional solid-state method, and the microwave dielectric properties were investigated. X-ray diffraction results illustrated that pure Ce 2 (MoO 4) 2 (Mo 2 O 7) structure formed upon sintering at 600 °C-725 °C. [CeO 7 ], [CeO 8 ], [MoO 4 ], and [MoO 6 ] polyhedra were connected to form a three-dimensional structure of CMO ceramics. Analysis based on chemical bond theory indicated that the Mo–O bond critically affected the ceramics' performance. Furthermore, infrared-reflectivity spectra analysis revealed that the primary polarisation contribution was from ionic polarisation. Notably, the optimum microwave dielectric properties of ε r = 10.69, Q·f = 49,440 GHz (@ 9.29 GHz), and τ f = −30.4 ppm/°C were obtained in CMO ceramics sintered at 700 °C. [ABSTRACT FROM AUTHOR]

This research work presents a modelling strategy to analyse thermal conversion rates of two thermal wood modification processes based on time-temperature superposition method. It gathers in a single study different original and bibliographic experimental works analysing the dry mass variation that occurs during thermal and hydro-thermal wood modification processes. The mass loss kinetic was successfully modelled using a modified Arrhenius approach. The time-temperature superposition method allowed to define for each wood modification process a master curve and its time shift depending on the treatment temperature. The analysis of ventilated oven and saturated steam treatments pointed out the existence of a continuous single kinetic for the ventilated oven which became more complex for saturated steam since a second kinetic stage appeared. This kinetic difference was sustained by infrared spectra chemical analysis which showed that hemicelluloses degraded much faster in presence of steam while lignin degradation occurred in both conditions. [ABSTRACT FROM AUTHOR]

In clinical treatment, the analytical quality assessment of the delivery of chemotherapeutic preparations is required to guarantee the patient's safety regarding the dose and most importantly the appropriate anticancer drug. On its own, the development of rapid analytical methods allowing both qualitative and quantitative control of the formulation of prepared solutions could significantly enhance the hospital's workflow, reducing costs, and potentially providing optimal patient care. UV-visible spectroscopy is a nondestructive, fast, and economical technique for molecular characterization of samples. A discrimination and quantification study of three chemotherapeutic drugs doxorubicin, daunorubicin, and epirubicin was conducted, using clinically relevant concentration ranges prepared in 0.9% NaCl solutions. The application of the partial least square discriminant analysis PLS-DA method on the UV-visible spectral data shows a perfect discrimination of the three drugs with a sensitivity and specificity of 100%. The use of partial least square regression PLS shows high quantification performance of these molecules in solution represented by the low value of root mean square error of calibration (RMSEC) and root mean square error of cross validation (RMSCECV) on the one hand and the high value of R -square on the other hand. This study demonstrated the viability of UV-visible fingerprinting (routine approach) coupled with chemometric tools for the classification and quantification of chemotherapeutic drugs during clinical preparation. [ABSTRACT FROM AUTHOR]

This work describes simple analytical formulas to describe the fluorescence line-narrowed (FLN) spectra of weakly coupled chromophores in the presence of excitation energy transfer (EET). Modeling studies for dimer systems (assuming low fluence and weak coupling) show that the FLN spectra (including absorption and emission spectra) calculated for various dimers using our model are in good agreement with spectra calculated by: (i) the simple convolution method and (ii) the more rigorous treatment using the Redfield approach [T. Renger and R. A. Marcus, J. Chem. Phys. 116, 9997 (2002)]. The calculated FLN spectra in the presence of EET of all three approaches are very similar. We argue that our approach provides a simplified and computationally more efficient description of FLN spectra in the presence of EET. This method also has been applied to FLN spectra obtained for the CP47 antenna complex of Photosystem II reported by Neupane et al. [J. Am. Chem. Soc. 132, 4214 (2010)], which indicated the presence of uncorrelated EET between pigments contributing to the two lowest energy (overlapping) exciton states, each mostly localized on a single chromophore. Calculated and experimental FLN spectra for CP47 complex show very good qualitative agreement [ABSTRACT FROM AUTHOR]

Objectives: In parts I and II of our review of physicochemical research performed on homeopathic preparations, we identified relevant publications and analyzed the data in terms of individual experiments, looking for the most promising techniques that were used in the past. In this third part, we analyze the results of the experiments seeking to extract information about the possible modes of action underpinning homeopathic preparations. Methods: We summarized the results from the 11 experimental areas previously introduced, extracting the general findings and trends. We also summarized the results in terms of specific research topics: aging, medium used for potentization, sample volume, temperature, material of potentization vessel, and, finally, the use of molecules to probe homeopathic samples. Results: We identified a number of effects that appear consistently throughout the data: Differences to controls seem to increase with: time, moderate temperature, small samples volume, and in ionic medium, whereas high temperatures seem to abolish differences to controls. Based on the present analysis, there is no consistent evidence to date for the nanoparticle hypothesis to explain specific homeopathic treatment effects. However, the quantum coherence domain hypothesis, the dynamic water cluster hypothesis, and the weak quantum theory are still contenders and need to be further assessed experimentally. Conclusions: The field requires further targeted experimentation to validate past findings reporting differences between homeopathic dilutions and controls, and to expand these findings by specifically testing the three main working hypotheses that are currently at hand. [ABSTRACT FROM AUTHOR]

Previously, we and other laboratories have reported an unusual and strong Raman optical activity (ROA) induced in solvents by chiral dyes. Various theories of the phenomenon appeared, but they were not capable of explaining fully the observed ROA band signs and intensities. In this work, an analysis based both on the light scattering theory and dedicated experiments provides a more complete understanding. For example, double‐cell magnetic circular dichroism and magnetic ROA experiments with copper‐porphyrin complex show that the induced chirality is observed without any contact of the solvents with the complex. The results thus indicate that a combination of electronic circular dichroism (ECD) with the polarized Raman scattering is responsible for the effect. The degree of circularity of solvent vibrational bands is a principal molecular property participating in the event. The insight and the possibility to predict the chirality transfer promise future applications in spectroscopy, chemical analysis and polarized imaging. [ABSTRACT FROM AUTHOR]

Previously, we and other laboratories have reported an unusual and strong Raman optical activity (ROA) induced in solvents by chiral dyes. Various theories of the phenomenon appeared, but they were not capable of explaining fully the observed ROA band signs and intensities. In this work, an analysis based both on the light scattering theory and dedicated experiments provides a more complete understanding. For example, double‐cell magnetic circular dichroism and magnetic ROA experiments with copper‐porphyrin complex show that the induced chirality is observed without any contact of the solvents with the complex. The results thus indicate that a combination of electronic circular dichroism (ECD) with the polarized Raman scattering is responsible for the effect. The degree of circularity of solvent vibrational bands is a principal molecular property participating in the event. The insight and the possibility to predict the chirality transfer promise future applications in spectroscopy, chemical analysis and polarized imaging. [ABSTRACT FROM AUTHOR]

Rationale: The dinoflagellate genera Gambierdiscus and Fukuyoa are producers of toxins responsible for Ciguatera Poisoning (CP). Although having very low oral potency, maitotoxins (MTXs) are very toxic following intraperitoneal injection and feeding studies have shown they may accumulate in fish muscle. To date, six MTX congeners have been described but two congeners (MTX2 and MTX4) have not yet been structurally elucidated. The aim of the present study was to further characterize MTX4. Methods: Chemical analysis was performed using liquid chromatography coupled to a diode-array detector (DAD) and positive ion mode high-resolution mass spectrometry (LC/HRMS) on partially purified extracts of G. excentricus (strain VGO792). HRMS/MS studies were also carried out to tentatively explain the fragmentation pathways of MTX and MTX4. Results: The comparison of UV and HRMS (ESI+) spectra between MTX and MTX4 led us to propose the elemental formula of MTX4 (C157H241NO68S2, as the unsalted molecule). The comparison of the theoretical and measured m/z values of the doubly charged ions of the isotopic profile in ESI+ were coherent with the proposed elemental formula of MTX4. The study of HRMS/MS spectra on the tri-ammoniated adduct ([M - H + 3NH4]2+) of both molecules gave additional information about structural features. The cleavage observed, probably located at C99-C100 in both MTX and MTX4, highlighted the same A-side product ion shared by the two molecules. Conclusions: All these investigations on the characterization of MTX4 contribute to highlighting that MTX4 belongs to the same structural family of MTXs. However, to accomplish a complete structural elucidation of MTX4, an NMR-based study and LC/HRMSn investigation will have to be carried out. [ABSTRACT FROM AUTHOR]

In the last decade, ground-based high-resolution Doppler spectroscopy (HRS) has detected numerous species in transiting and non-transiting hot Jupiters, and is ideally placed for atmospheric characterization of warm Neptunes and super Earths. Many of these cooler and smaller exoplanets have shown cloudy atmospheres from low-resolution near-infrared observations, making constraints on chemical species difficult. We investigate how HRS can improve on these given its sensitivity to spectral line cores which probe higher altitudes above the clouds. We model transmission spectra for the warm Neptune GJ 3470b and determine the detectability of H2O with the CARMENES, GIANO, and SPIRou spectrographs. We also model a grid of spectra for another warm Neptune, GJ 436b, over a range of cloud-top pressure and H2O abundance. We show H2O is detectable for both planets with modest observational time and that the high H2O abundance-high cloud deck degeneracy is broken with HRS. However, meaningful constraints on abundance and cloud-top pressure are only possible in the high-metallicity scenario. We also show that detections of CH4 and NH3 are possible from cloudy models of GJ 436b. Lastly, we show how the presence of the Earth's transmission spectrum hinders the detection of H2O for the most cloudy scenarios given that telluric absorption overlaps with the strongest H2O features. The constraints possible with HRS on the molecular species can be used for compositional analysis and to study the chemical diversity of such planets in the future. [ABSTRACT FROM AUTHOR]

Athletes regularly consume commercially available food and sports shot products, carbohydrate beverages, and water to improve their physical exertion and to possibly prevent or relieve exercise-associated muscle cramps (EAMCs)—often experienced during practice, training, or competition. Acetic acid, a component of interest within these products, has been recognized for its potential role in cramp reduction. Acetic acid is postulated to mitigate cramping by decreasing alpha motor neuron activity through oropharyngeal stimulation and inhibitory neurotransmitter production, while aiding in the role acetylcholine plays in muscle contraction and relaxation. The purpose of this research is to analytically assess the most viable sources of acetic acid from substances that athletes ingest before or when experiencing these cramps. The range of samples investigated were based on their widespread use in the athletic world: dill and sweet pickle juices, yellow mustard, sweet relish, apple cider vinegar, Hot Shot, PJ Shot, PJ Sport, E-Lyte Sport, Powerade, Gatorade, Smartwater, and Propel (with electrolytes). As hypothesized, pH and enzymatic assay or spectroscopic analyses revealed that yellow mustard, sweet relish, all pickle juices, and the pickle juice products were composed of moderate amounts of acetic acid. Based on established studies resulting in EAMC relief, acetic acid consumption, and the appropriate serving size, the yellow mustard, PJ Shot, and all pickle juices would be the most practical and palatable sources of acetic acid for strength and conditioning professionals to recommend that athletes consume for the possible prevention or alleviation of muscle cramps. [ABSTRACT FROM AUTHOR]

Background: Dengue burden is increasing day-by-day globally. A rapid, sensitive, cost-effective early diagnosis kit is the need of the hour. In this study, a label-free electrochemical immunosensor was proposed for dengue virus detection. A modified Polyaniline (PANI) coated Glassy Carbon (GC) electrode, immobilized with DENV NS1 antibody was used to detect the circulating DENV NS1 antigen in both spiked and infected sample. Methods: Cloning, purification and expression of DENV NS1 protein in Escherichia coli ( E. coli) was performed and sensor design, PANI modification on GC electrode surface by electrochemical polymerization and immobilization of NS1 antibody on the modified electrode surface was done and finally the analytical performance of the electrochemical immunosensor was done using Cyclic Voltammetry (CV) and Electrochemical Impedance Spectroscopy (EIS). Results: CV and EIS were used to study and quantitate the circulating DENV antigen. The calibration curve showed wide linearity, good sensitivity (Slope=13.8% IpR/ ml.ng-1) and distribution of data with a correlation coefficient (R) of 0.997. A lower Limit of Detection (LOD) was found to be 0.33 ng.ml-1 which encourages the applicability of the sensor. Conclusion: Thus, a PANI based new electrochemical immunosensor has been developed which has the potential to be further modified for the development of cost effective, point of care dengue diagnostic kit. [ABSTRACT FROM AUTHOR]

Since the advent of X-Ray fluorescence (XRF) spectrum analysis technology, with its wide range of elemental analysis, rapid, nondestructive analysis characteristics, and better detection accuracy, the workload of semi-quantitative analysis has taken half of the total analysis in contemporary research institutes and university laboratories engaged in material research. In addition, XRF has been widely and efficiently used in analytical chemistry, geological and mineral survey, ecological and environmental monitoring, food and drug detection, archeology and other fields. XRF spectrum processing technology is based on the application of mathematical principles, using reasonable algorithms to optimize the processing of spectrum data to contribute more accurate quantitative analysis of key elements. Over the years, XRF spectrum processing technology has formed a relatively complete set of processes, in each step of spectrum processing, plenty of research work and paper reports have been implemented and developed. This paper mainly reviews the representative algorithms and their progress in spectrum smoothing, background subtraction and overlapping peak decomposition of XRF spectrum analysis technology, analyzes their applications in related fields, summarizes and proposes the development direction of some potential algorithms. [ABSTRACT FROM AUTHOR]

In this study, Chinese yam starch-water suspension (8%) were subjected to high-pressure homogenization (HPH) at 100 MPa for increasing cycle numbers, and its effect of on the physicochemical properties of the starch was investigated. Results of the polarizing microscope observations showed that the starch granules were disrupted (i.e. greater breakdown value) after HPH treatment, followed by a decrease in cross polarization. After three HPH cycles, the crystallinity of starch decreased, while the crystal type remained unaltered. Meanwhile, the contents of rapidly digestible starch and slowly digestible starch were increased. On the contrary, resistant starch content was decreased. Our results indicate that HPH treatment resulted in reduction of starch crystallinity and increase of starch digestibility. [ABSTRACT FROM AUTHOR]

Three new 3,4,6-trisubstituted α-pyrone derivatives, namely 6-(2′R-hydroxy-3′E,5′E-diene-1′-heptyl)-4-hydroxy-3-methyl-2H-pyran-2-one (1), 6-(2′S-hydroxy-5′E-ene-1′-heptyl)-4-hydroxy-3-methyl-2H-pyran-2-one (2), and 6-(2′S-hydroxy-1′-heptyl)-4 -hydroxy-3-methyl-2H-pyran-2-one (3), together with one known compound trichodermic acid (4), were isolated from the solid-substrate fermentation culture of Penicillium ochrochloronthe associated the roots of Taxus media. Compounds 1–4 displayed the antimicrobial activity selectively against tested fungal and bacterial strains with minimum inhibitory concentration (MIC) values ranging from 12.5 to 100 μg/ml. Furthermore, we found that only compound 4 exhibited moderate cytotoxicity against five human cancer cells (A549, LN229, MGC, LOVO, and MDA231) with IC50 values of 51.45, 23.43, 39.16, 46.97, and 42.85 μg/ml, respectively. [ABSTRACT FROM AUTHOR]

Coix lachryma-jobi L. var. ma-yuen has been a source of food and traditional folk medicine in some parts of Asia for thousands of years; however, the roots of this plant have not been phytochemically investigated. Herein, we report the isolation of a new benzoxazinoid glycoside, coixlachryside B (1), along with ten known compounds (2–11), from the roots of C. lachryma-jobi var. ma-yuen using a variety of chromatographic methods. Among the known compounds, the absolute configuration of compound 4 was determined. The structures of all compounds were elucidated by interpreting NMR spectroscopic data, and experimental and calculated electronic circular dichroism spectra. [ABSTRACT FROM AUTHOR]

Germanium powder was thermally evaporated under a vacuum onto unheated substrates as well as substrates heated to 200 °C. The striking feature was that the resulting films were transparent. Chemical analysis using x-ray photoelectron spectroscopy depth profiling indicated that oxygen was present throughout the thickness of the films, and therefore the films were composed of substoichiometric germanium oxide. The source of oxygen was investigated, and traced to the source material. Subsequently, the optical constants and the band gaps of the films were determined from spectrophotometric measurements. These properties were found to be intermediate between those of pure germanium and germanium dioxide, with values appropriate for optical applications in the visible range. [ABSTRACT FROM AUTHOR]

Guided by theoretical predictions, the rotational spectra of the mono- and bideuterated species of trans-1-chloro-2-fluoroethylene, CH35ClCDF, CH37ClCDF, CD35ClCHF, CD37ClCHF, CD35ClCDF, and CD37ClCDF, have been recorded for the first time. Assignment of the ΔJ=0 and ΔK-1= +1 bands with K-1=3,4,5,… (all isotopic species) as well as of several ΔJ= ±1 and ΔK-1= +1 transitions (all isotopic species except CH37ClCDF, CD37ClCHF, and CD37ClCDF) led to the accurate determination of the ground-state rotational constants, the quartic, and some sextic centrifugal distortion constants, as well as the nuclear quadrupole coupling constants for both 35Cl and 37Cl in good agreement with corresponding theoretical predictions based on high-level coupled-cluster calculations. Inconsistencies of the present spectroscopic parameters with respect to those reported earlier for the two main isotopologues, i.e., CH35ClCHF and CH37ClCHF, necessitated a reinvestigation of the rotational spectra for these two isotopic species. Supported by quantum chemical calculations, the previously recorded spectra are reassigned to a vibrationally excited state, while analysis of the ΔJ=0 and ΔK-1=+1 as well as some ΔJ=±1 and ΔK-1=+1 transitions provided a revised set of spectroscopic parameters for the vibrational ground state of these two isotopic species. [ABSTRACT FROM AUTHOR]

Rare earth doped BaCeO3 has been widely investigated as a proton conducting material. Trivalent dopants are generally assumed to fully occupy the Ce4+-site, and thereby introduce oxygen vacancies into the perovskite structure. Recent studies indicate the possibility of partial dopant incorporation onto the Ba2+-site concomitant with BaO evaporation, reducing the oxygen vacancy content. Because proton incorporation requires, as a first step, the generation of oxygen vacancies such dopant partitioning is detrimental to protonic conductivity. A quantitative Extended X-ray Absorption Fine Structure (EXAFS) study of BaCe0.85M0.15O3-δ(M=Yb,Gd) is presented here along with complementary x-ray powder diffraction and electron probe chemical analyses. The EXAFS results demonstrate that as much as 4.6% of the ytterbium and 7.2% of the gadolinium intended for incorporation onto the Ce site, in fact, resides on the Ba site. The results are in qualitative agreement with the diffraction and chemical analyses, which additionally show an even greater extent of Nd incorporation on the Ba site. [ABSTRACT FROM AUTHOR]

Reciprocal-space analysis offers several advantages for determining critical point parameters in optical and other spectra, for example the separation of baseline effects, information, and noise in low-, medium-, and high-index Fourier coefficients, respectively. However, endpoint-discontinuity artifacts can obscure much of the information when segments are isolated for analysis. We developed a procedure for eliminating these artifacts and recovering buried information by minimizing in the white-noise region the mean-square deviation between the Fourier coefficients of the data and those of low-order polynomials, then subtracting the resulting coefficients from the data over the entire range. We find that spectral analysis is optimized if no false data are used, i.e., when the number of points transformed equals the number of actual data points in the segment. Using fractional differentiation we develop a simple derivation of the variation of the reciprocal-space coefficients with index n for Lorentzian and Gaussian line shapes in direct space. More generally, we show that the definition of critical point energies in terms of phase coherence of the Fourier coefficients allows these energies to be determined for a broad class of line shapes even if the direct-space line shapes themselves are not known. Limitations for undersampled or highly broadened spectra are discussed, along with extensions to two- or higher-dimensional arrays of data. © 2001 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Presents information on a study which investigated a single longitudinal mode simultaneous dual wavelength laser in neodymium host crystals using a standing wave model. Experimental method; Results; Conclusion.

In the article has been presented an analysis of susceptibility of selected dental materials, made in the CAD/CAM technology. The morphology and structural properties of selected dental materials and their composites were determined by using XRPD (X-ray powder diffraction) techniques, as well as the IR (infrared) spectroscopy. Moreover, an adhesion as well as development of biofilm by oral microorganisms has been studied. It has been shown that a degree of the biofilm development on the tested dental materials depended on microorganism genus and species. Streptococcus mutans has demonstrated the best adhesion to the tested materials in comparison with Candida albicans and Lactobacillus rhamnosus. However, the sintered materials such as IPS e.max® and the polished IPS e.max® have showed the best "anti-adhesive properties" in relation to S. mutans and L. rhamnosus that have not formed the biofilm on the polished IPS e.max® sample. Furthermore, S. mutans have not formed the biofilm on both surfaces. On the contrary to S. mutans and L. rhamnosus, C. albicans has demonstrated the adhesive properties in relation to the above-mentioned surfaces. Moreover, in contrast to S. mutans and C. albicans, L. rhamnosus has not formed the biofilm on the polished IPS Empress material. [ABSTRACT FROM AUTHOR]

Six 8,12-epoxyguaiane sesquiterpenes (1 – 6), together with two known 2-(2-phenylethyl)chromone derivatives (7 – 8) were isolated from agarwood originating from Aquilaria filaria. Their structures were established by spectroscopic methods including IR, HRESIMS, 1D, and 2D NMR, and comparison with the published data. The absolute configuration of compound 1 was unambiguously determined by quantum chemical calculation of the electronic circular dichroism (ECD) spectrum. All compounds were tested for their α -glucosidase inhibitory activity and cytotoxicity. Compound 5 showed significant α -glucosidase inhibitory activity with IC 50 value of 253.2 ± 9.7 μM (Acarbose, 743. 4 ± 3.3 μM). Compounds 2 – 4 displayed weak cytotoxicity against K562 tumor cell lines. Unlabelled Image [ABSTRACT FROM AUTHOR]

We use integral field spectroscopic (IFS) observations from Gemini Multi-Object Spectrograph-North (GMOS-N) to analyse the ionized gas in the principal star-forming region in the blue compact dwarf galaxy SBS 1415+437. The IFS data enable us to map the weak auroral line [O iii ] λ4363 at a spatial scale of ∼6.5 pc across a region of ∼143 × 143 pc2. This in turn allows us to use the robust direct T e-method to map the ionic and elemental abundances of nitrogen (N) along with the alpha-elements, oxygen (O), neon (Ne), sulphur (S), and argon (Ar). We utilize these abundances to map the relative abundances of N, Ne, S, and Ar with respect to O. We segment this pre-dominantly photoionized region of study into elliptical annuli on the basis of the H α flux distribution to study the variation of chemical abundances and their ratios, and find no significant chemical variation. We also perform chemical abundance analysis on the integrated spectra of the region under study and elliptical annuli within it. We find that the inferred abundances are in agreement with the median of the abundances obtained from the chemical abundance maps of the principal star-forming region and the mapped values within annuli. The finding has important implications for direct comparison with high-redshift observations, where spatial resolution is not available, and for a consistent approach to track chemical evolution across cosmic time. [ABSTRACT FROM AUTHOR]

Phytochemical study on rhizomes of Cimicifuga dahurica resulted in the isolation of nine new neolignan and phenylpropanoid glycosides, cimicifugasides A-E (1, 2, 7–9), cimicifugamides B-D (3 – 5), shomaside G (6) along with four known compounds (10 − 13). Their structures were identified by extensive spectroscopic analyses (1D-, 2D-NMR, MS, CD, IR, UV) and chemical methods. Their anti-inflammatory potentials were evaluated by measuring their effects on PGE 2 production of LPS-stimulated RAW264.7 cells, and compounds 12 and 13 showed moderate anti-inflammatory activities. Unlabelled Image [ABSTRACT FROM AUTHOR]

Two kinds of biologically active compounds were isolated from the MeOH extract of the Early Cretaceous Burmese amber [99 million years ago (Ma)], which is older than the K-Pg boundary (65 Ma). These compounds had inhibitory activity against the hypersensitive mutant yeast strain (zds1 ∆ erg3 ∆ pdr1 ∆ pdr3∆) with respect to Ca2+ signal transduction. They were identified as 16,17-bisnordehydroabietic acid (1) and 16,17-bisnorcallitrisic acid (2), respectively, on the basis of spectral analyses including HREIMS, 1D, and 2D NMR. Both have faint growth restoring activities around the clear inhibition zone against the mutant yeast on the 0.31–0.16 μg/spot. This is the first report of direct structural elucidation of 1 and 2 and the biologically active compounds derived from Burmese amber. Unlabelled Image [ABSTRACT FROM AUTHOR]

Three new compounds (1 – 3), euphorimaoid A (1), euphorimaoid B (2), 1 α -hydroxy-3 β -acetoxy-olean-9,12-diene (3), two firstly isolated natural products 3 β -acetyloxy-olean-13(18)-en-12-one (4) and 18,19-epoxyolean-3 β -ol acetate (5), together with 13 known compounds (6 – 18) have been identified from the aerial parts of Euphorbia pulcherrima Willd. Structures of compounds 1 – 5 were elucidated by comprehensive spectroscopic analysis. The absolute configuration of euphorimaoid A (1) was established using single crystal X-ray diffraction analysis. All the isolates were evaluated for their inhibition of osteoclastogenesis in BMMs. Among them, compounds 7 and 10 showed significantly inhibition in a concentration-dependent manner. Unlabelled Image [ABSTRACT FROM AUTHOR]

Two new hexaketides, xylarodons B (1) and C (2), were isolated from solid cultures of the endophytic fungus Xylaria sp. SC1440. The structures of these compounds were elucidated on the basis of detailed 1D, 2D NMR, and HRESIMS analysis. Their absolute configurations were established by experimental and TDDFT calculated ECD spectra. The isolated compounds were evaluated for cytotoxic and tyrosinase inhibitory activity. [ABSTRACT FROM AUTHOR]

Abstract A new series of 2‑styryl phenanthro[9,10‑ d ]oxazoles was readily accessible from the condensation reaction of 9,10‑phenanthroquinone with cinnamaldehydes in the presence of lactic acid. All these styryl dyes were isolated in good yields and characterized by various analytical and spectroscopic techniques. One of the dyes containing NO 2 group (3d) was structurally characterized by single crystal X-ray analysis. These dyes displayed emission in blue to green region with larger Stokes shift values characteristic to the nature of substituents. In addition, positive solvatochromic trend was observed by increasing the solvent polarity suggestive of a more stabilized polar excited state. Moreover, the addition of trifluoroacetic acid leads to a prominent blue-shift in visible and emission color changes owing to the protonation of the nitrogen atom of oxazole moiety. Among the all, the oxazole derivative having NMe 2 group (3b) exhibits good response to acidic pH in the range of 3.0 to 5.6 with a good linearity upon decreasing the pH from 8.0 to 2.16. The absorption studies were further supported by density functional theory calculations. Graphical Abstract Unlabelled Image Highlights • Synthesis and characterization of a series of 2-Styryl phenanthro[9,10- d ]oxazoles are described. • The dyes exhibit positive solvatochromism, acidochromism and halochromism. • The protonation studies indicate the formation of a mono and dication species on protonation. • The impact of the nature of substituted styryl fragment on electronic properties is strengthened by DFT calculations. [ABSTRACT FROM AUTHOR]

Abstract Multivariate analyses are increasingly popular to explore the underlying structure of multivariate datasets, which are more and more prevalent in analytical chemistry. However, difficulties can be associated with estimating the number of components for the data with considerable coherence and noise. The method of Angle Distribution of Loading Subspace (ADLS) has been proposed to estimate the number of components for Principal Component Analysis (PCA) and PARAllel FACtor analysis (PARAFAC), which showed some advantages, in particular in the case of datasets with high coherence, over the commonly used methods (scree plot and cross-validation in PCA, and core consistency diagnostics (CORCONDIA) in PARAFAC). In this paper, we systematically improved and applied ADLS to estimate the number of components in different multivariate methods including, Multivariate Curve Resolution (MCR), PARAFAC and four-way PARAFAC. Firstly, we showed that ADLS performed better when estimating the chemical rank for MCR analysis, compared with scree plots. As well as this, we improved ADLS in multi-way analysis (three- and four-way PARAFAC) by calculating the loading subspace in advance using the Khatri-Rao product. The improved ADLS in multi-way analysis provided the correct result for the simulated three-way fluorescence datasets with unevenly distributed coherence at different dimensions, while the previous version of ADLS showed biased results and CORCONDIA / split-half analysis provided relatively unstable results. Moreover, ADLS was used to estimate the chemical rank for a four-way real-life fluorescence dataset analyzed by four-way PARAFAC. In this case the result of chemical rank results from ADLS was more precise and informative compared with CORCONDIA /split-half analysis in four-way analysis. Graphical abstract fx1 Highlights • Angle Distribution of Loading Subspace (ADLS) is applied in different multivariate methods for a chemical rank estimation. • ADLS outperforms scree plot in MCR analysis. • Loading subspace is calculated using the Khatri-Rao product to improve ADLS in multi-way analysis. • ADLS shows advantage compared with core consistency diagnose in four-way analysis. [ABSTRACT FROM AUTHOR]

Two new carotane-type sesquiterpenes named trichocaranes E (1) and F (2), along with two known ones CAF-603 (3) and trichocarane C (4), were isolated from cultures of the insect pathogenic fungus Isaria fumosorosea. Their structures and relative configurations were elucidated by extensive spectroscopic analysis and X-ray crystallography. Compounds 1-3 showed potent cytotoxic activities against six tumor cell lines MDA, MCF-7, SKOV-3, Hela, A549, HepG2 with IC50 values in a concentration range of 0.1-6.0 μg/ml. [ABSTRACT FROM AUTHOR]

Highlights • The visual determination of malachite green in fish. • A simple visual method for use in the field. • The solid phase extraction of malachite green in polymer matrix. Abstract Polymethylmethacrylate matrix has been developed as an analytical device for visual and spectrophotometric determination of malachite green. Based on the studied effects of different pH levels, temperature, contact time and diverse ions, optimum analysis conditions have been established. For malachite green, the calibration graph was linear in the range of 0.5–30 mg·L−1 in the samples with the detection limit of 1 mg·kg−1. The proposed simple method makes it possible to determine malachite green visually in the concentration range 8–30 mg·L−1 using a colour scale. The method has been implemented for determination of malachite green in various sea fish samples. [ABSTRACT FROM AUTHOR]

Nowadays, more than 95 different Streptococcus pneumoniae serotypes are known, being less than one third responsible for the majority of severe pneumococcal infections. After the introduction of conjugate vaccines, a change in the epidemiology of the serotypes causing invasive pneumococcal disease has been observed making the surveillance of circulating serotypes especially relevant. Some recent studies have used matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) technology to identify the most frequent pneumococcal serotypes that cause invasive disease. The objectives of this study were to evaluate the efficacy of previously described discriminatory peaks determined by MALDI-TOF MS for the identification of serotypes 6B, 19F, 19A and 35B using reference and clinical isolates and to try to identify other discriminatory peaks for serotypes 11A, 19F and 19A using transformed pneumococcal strains. Most of the proposed peaks defined in the literature for the identification of serotypes 6B, 19F, 19A, 35B were not found in the spectra of the 10 reference isolates nor in those of the 60 clinical isolates tested corresponding to these four serotypes. The analysis and comparison of the mass spectra of genetically modified pneumococci (transformed strains) did not allow the establishment of new discriminatory peaks for serotypes 11A, 19F, and 19A. MALDI-TOF MS in the usual range of 2,000 to 20,000 m/z did not prove to be a valid technique for direct S. pneumoniae serotyping. [ABSTRACT FROM AUTHOR]

As cellulose nanocrystals (CNCs) are increasing in production, establishing safe workplace practices in industry will be paramount to their continued use and growth. Particles other than CNCs with similar high aspect ratios have exhibited toxicity on inhalation. Safeguards are needed to monitor concentrations of CNCs in air in industrial and laboratory settings to protect workers. However, because of their size, morphology, and chemical makeup, CNCs are difficult to characterize and differentiate from other dust and cellulose products. This work is focused on developing an effective method of characterizing the concentration of airborne ultrafine CNCs that may deposit in the respiratory tract. CNCs were tagged with rhodamine b (RhB-CNCs) for improved visualization and characterized using UV-vis spectroscopy (UV-vis), transmission electron microscopy (TEM), and dynamic light scattering (DLS), then aerosolized and collected via a novel method using plastic impingers. Concentration of RhB-CNCs was measured using UV-vis and scanning mobility particle sizer (SMPS). The plastic impinger with 3D-printed nozzle collected airborne CNCs at an efficiency that improves upon commercially available impingers for relevant particle sizes. [ABSTRACT FROM AUTHOR]

Two new secolignans, 3,4-trans-3-hydroxymethyl-4-[bis(4-hydroxy-3- methoxyphenyl)methyl]butyrolactone (1) and 3,4-trans-3-hydroxymethyl-4- [bis(3,4-dimethoxyphenyl)methyl]butyrolactone (2) have been isolated from the roots of Urtica fissa E.Pritz. Their structures were determined on the basis of spectroscopic methods, especially 1H NMR, 13C NMR, 2D NMR, and HR-ESI-MS. The inhibitory effects on N1 and N2, two subtypes of neuraminidases (NAs), of these two compounds were assayed. [ABSTRACT FROM AUTHOR]

Two new tetralone derivatives, named cyclopalosides A (1) and B (2), were isolated from the leaves of Cyclocarya paliurus by column chromatography on silica gel, reversed-phase C18 silica gel and preparative HPLC. Their chemical structures were established on the basis of extensive analyses of spectroscopic data. Their structural characteristic is tetralone glycoside with a caffeoyl unit. The antioxidant activities of compound 1 were evaluated by using hydroxyl, superoxide anion, and DPPH radical scavenging assay. [ABSTRACT FROM AUTHOR]

We tested the solubility and dissolution of tamoxifen citrate to ascertain the optimal conditions for faster dissolution. Using the solvent evaporation method and hydrophilic carriers, we formulated tamoxifen citrate (TC) that contained solid dispersions (SDs). We increased the solubility and dissolution rate of TC with a solid dispersion system that consisted of polyethylene glycol (PEG-6000), beta-cyclodextrin (β-CD), and a combination of carriers. Physicochemical characteristics of solubility (mg/ml) were found to be 0.987±0.04 (water), 1.324±0.05 (6.8pH PBS), and 1.156±0.03 (7.4 pH PBS) for F5 formulation, percentage yield was between 98.74 ± 1.11% and 99.06 ± 0.58%, drug content was between 98.06±0.58 and 99.06±1.10, and dissolution studies binary complex showed a faster release of TC as compared to a single polymer and pure drug. Furthermore, thermal properties, physicochemical drug and polymer interaction, crystal properties, and morphology were determined using differential scanning calorimetry (DSC), infrared spectroscopy (FT-IR), X-ray differential studies, and scanning electron microscopy. We used the same proportion of carrier concentrations of the formulations to calculate the solubility of TC. Our results demonstrated that increased concentrations of β-C yielded an improved solubility of TC, which was two times higher than pure TC. The uniformity in drug content was 97.99 %. A quicker drug release occurred from the binary complex formulation as seen in the dissolution profile. FTIR demonstrated an absence in the physicochemical interaction between the drug and carriers. The drug was also found to be dispersed in the amorphous state as revealed by DSC and XRD. The drug concentration did not vary during various storage conditions. Our in vivo studies demonstrated that SD displayed significantly higher values of Cmax (p < 0.05) and AUC0-24 (p < 0.05) as compared to free TC. Furthermore, Tmax in SD was significantly lower (p < 0.05), as compared to free TC. [ABSTRACT FROM AUTHOR]

Mycotoxins are the foremost naturally occurring contaminants of food products such as corn, peanuts, tree nuts, and wheat. As the secondary metabolites, mycotoxins are mainly synthesized by many species of the genera Aspergillus, Fusarium and Penicillium, and are considered highly toxic and carcinogenic to humans and animals. Most mycotoxins are detected and quantified by analytical chemistry-based methods. While mycotoxigenic fungi are usually identified and quantified by biological methods. However, these methods are time-consuming, laborious, costly, and inconsistent because of the variability of the grain-sampling process. It is desirable to develop rapid, non-destructive and efficient methods that objectively measure and evaluate mycotoxins and mycotoxigenic fungi in food. In recent years, some spectroscopy-based technologies such as hyperspectral imaging (HSI), Raman spectroscopy, and Fourier transform infrared spectroscopy have been extensively investigated for their potential use as tools for the detection, classification, and sorting of mycotoxins and toxigenic fungal contaminants in food. HSI integrates both spatial and spectral information for every pixel in an image, making it suitable for rapid detection of large quantities of samples and more heterogeneous samples and for in-line sorting in the food industry. In order to track the latest research developments in HSI, this paper gives a brief overview of the theories and fundamentals behind the technology and discusses its applications in the field of rapid detection and sorting of mycotoxins and toxigenic fungi in food products. Additionally, advantages and disadvantages of HSI are compared, and its potential use in commercial applications is reported. [ABSTRACT FROM AUTHOR]

Abstract With the extensive use of plastic in our daily lives, the increasing requirements for disposal and quality control of plastic products raise more concerns. Laser-induced breakdown spectroscopy (LIBS) has the advantages of requiring little or no sample pretreatment and being high-speed and minimally invasive. The combination of LIBS and analytical chemistry methods has become an efficient method of plastic analysis. This review provides a comprehensive overview of LIBS instruments used for plastic analysis, discrimination among different types of plastics, and the qualitative and quantitative analysis of plastic. Furthermore, applications of plastic are reviewed, including in toys, food containers, e-waste, etc. Finally, limitations and the potential developing trend for the topic are proposed. Highlights • The recent progress in plastic analysis using LIBS technology is presented. • LIBS instruments, analytical chemistry methods, and applications for plastic analysis are reviewed. • Advantages, problems (and their solutions), and future perspective for plastic analysis are commend. [ABSTRACT FROM AUTHOR]

Abstract Although arsenic (As) toxicity in soil vary depending on its chemical forms and oxidation states, regulatory limits for this compartment rely on total As content. Conventional methods of total As determination are expensive and time-consuming. The development of predictive techniques might enable a speditive assessment of As contamination in those scenarios, such as thermal spring sites, where exposure to the metalloid poses a threat to human health. The objective of this study was to assess the suitability of Visible Near Infrared spectrophotometry for predicting the total As content in highly calcareous thermal spring soils and the same aim was pursued for those elements (i.e. Al, Fe and Mn) the chemistry of which is tightly connected with that of As. A Partial Least Square approach, including cross-validation and external independent test, was used to relate the concentrations of the target elements to spectral data. The most accurate prediction was found for As with Pearson's coefficient, RMSE, RPD and SEP being equal to 0.94, 69.65, 2.9 and 66.99, respectively. Less accurate predictions were found for Al (r = 0.88; RMSE = 11014; RPD = 1.96; SEP = 11014) , Fe (r = 0.93; RMSE = 6921.1; RPD = 2.45; SEP = 6462.4), and Mn (r = 0.92; RMSE = 542.01; RPD = 2.43; SEP = 529.79). Graphical abstract fx1 Highlights • Arsenic contamination is a common scenario in thermal spring sites (TSS). • Soils in TSS of volcanic origin are generally highly calcareous. • Hyperspectral spectrophotometry enabled an accurate As prediction in TSS soils. • Other As-connected elements were predicted with good accuracy by the same technique. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • An integrated paper-based platform is proposed for the HSA concentration detection. • BCG reagent and HSA concentration is induced albumin-BCG complex for RGB detection. • HAS concentration of 36 real-world human samples are measured. • The results are in excellent agreement of R2 = 0.9912 versus official method. Abstract A rapid analytical platform composed of a paper-based chip (µPB-Chip) and a small analytic box is developed to determine the concentration of human serum albumin (HSA). In this study, a Bromocresol Green (BCG) reagent is dropped into the reaction area of the µPB-Chip, and the HSA concentration was derived from the R (red) value intensity of the albumin-BCG complex formed after a reaction process at 37 °C for 12 min. The effectiveness of the developed method is displayed using albumin concentrations ranging from 0 to 5 g/dL in HSA control samples. The measurement results acquired from 36 volunteer patient’s HSA samples are presented to be in good consistency with those obtained utilizing a conventional assay technique (R2 = 0.9912). Ultimately, the results show that the developed platform provides a convenient, economical and dependable method for HSA concentration detection. [ABSTRACT FROM AUTHOR]