Study of thermal currents in powder β-spodumene ceramics doped with Cuo, FeO and TiO2

Ternary-phase ceramic system of Li₂O Al₂O₃ 4SiO₂ doped with CuO, FeO and TiO₂ has been prepared and subjected to dc electrical conductivity and thermally stimulated depolarization current (TSDC) measurements as a function of temperature (30-250 °C) and field strength. The electrical conductivity results are explained by assuming both ionic and electronic conduction mechanisms coexist with different contributions over the whole temperature range of experiments. TSDC spectra have been found to be characterized by a broad intense relaxation peak, which can be attributed to an ionic charge polarization. The broad relaxation transitions are apparently a result of the nonuniform nature of this process. Activation energies are calculated for both dc electrical conductivity and TSDC according to Arrhenius equation and initial rise method, respectively.     

Synthesis of Potential Antiviral Agents for SARS-CoV-2 Using Molecular Hybridization Approach

We synthesized a set of small molecules using a molecular hybridization approach with good yields. The antiviral properties of the synthesized conjugates against the SAR-CoV-2 virus were investigated and their cytotoxicity was also determined. Among all the synthesized conjugates, compound 9f showed potential against SARS-CoV-2 and low cytotoxicity. The conjugates’ selectivity indexes (SIs) were determined to correlate the antiviral properties and cytotoxicity. The observed biological data were further validated using computational studies.     

Anti-Quorum Sensing and Anti-Biofilm Activity of Pelargonium × hortorum Root Extract against Pseudomonas aeruginosa: Combinatorial Effect of Catechin and Gallic Acid

HPLC-UV was used to compare the major constituents of two Pelargonium × hortorum cultivars and Pelargonium sidoides root extract. It revealed the presence of catechin and gallic acid in high concentrations and the absence of umckalin in P. × hortorum root extracts. The antibacterial activity of these extracts was screened against 19 Pseudomonas aeruginosa clinical isolates. P. × hortorum root extracts showed the lowest MIC values (512–1024 µg/mL). This activity was concluded to be attributable to the high concentrations of catechin and gallic acid. The anti-biofilm activity of catechin, gallic acid, and their combination was examined by a crystal violet assay. The combination reduced the percentage of strong and moderate biofilm-forming isolates from 52.63% to 5.26%. The impact on lasI and lasR genes expression using qRT-PCR and simultaneous docking against LasR protein was explored. The combination downregulated lasI and lasR gene expression in eight and six P. aeruginosa isolates, respectively, and showed the greatest docking score. Additionally, the in vivo protection capability of this combination in infected mice showed enhancement in the survival rate. Our study revealed the potential biofilm and quorum-sensing-inhibitory activity of the catechin and gallic acid combination as a novel alternative to inhibit bacterial pathogenicity.     

Preparation and Spectroscopic of Vanadyl(Ⅱ) Vitamin D_3 Amino Acid Mixed Complexes as Insulin Mimetic Drug

A new six intraperitoneal injection insulin-mimetic vanadyl(Ⅱ) compounds [(VD-1₃)(VO+2)(AA-1_n)] (where (n=1～6); AA₁=isoleucine, AA₂=threonine, AA₃=proline, AA₄=phenylalanine, AA₅=lysine and AA₆=glutamine) were synthesized by the chemical reactions between vitamin D₃ (VD₃), VOSO₄ and amino acids (AA_n) with equal molar ratio 1∶1∶1 in neutralized media. The structures of these complexes were elucidated by spectroscopic methods like, infrared and solid reflectance spectroscopes. Magnetic moments and electronic spectra reveal square pyramid geometrical structure of the complexes. The infrared spectra assignments of these complexes revealed that the chelation towards vanadyl(Ⅳ) ions existed via deprotonation of the hydroxyl group of VD₃ drug ligand and so amino acids act as bidentate ligand via N-amino and O-carboxylate groups. The anti-diabetic efficiency of these complexes were evaluated against streptozotocin induced diabetic male albino rats.     

Accurate radial basis function based neural network approach for analysis of photonic crystal fibers

In this paper, a new and an accurate artificial neural network approach (ANN) is presented for the analysis and design of photonic crystal fibers (PCFs). The new ANN approach is based on the radial basis functions which offer a very quick convergence and high efficiency during the ANN learning. The accuracy of the suggested approach is demonstrated via the excellent agreement between the results obtained using the presented approach and the results of the full vectorial finite difference method (FVFDM). In addition, a new design of highly birefringence PCF with low losses for the two polarized modes is presented using the proposed approach.     

A fully automated system with on-line micro solid-phase extraction combined with capillary liquid chromatography-tandem mass spectrometry for high throughput analysis of microcystins and nodularin-R in tap water and lake water

Microcystins and nodularins are cyclic peptide hepatotoxins and tumour promoters from cyanobacteria. The present study describes the development, validation and practical application of a fully automated analytical method based on on-line micro solid-phase extraction-capillary liquid chromatography-tandem mass spectrometry for the simultaneous determination of seven microcystins and nodularin-R in tap water and lake water. Aliquots of just 100 μL of water samples are sufficient for the detection and quantification of all eight toxins. Selected reaction monitoring was used to obtain the highest sensitivity. Good linear calibrations were obtained for microcystins (50-2000ng/L) and nodularin-R (25-1000 ng/L) in spiked tap water and lake water samples. Excellent interday and intraday repeatability were achieved for eight toxins with relative standard deviation less than 15.7% in three different concentrations. Acceptable recoveries were achieved in the three concentrations with both tap water matrix and lake water matrix and no significant matrix effect was found in tap water and lake water except for microcystin-RR. The limits of detection (signal to noise ratio=3) of toxins were lower than 56.6 ng/L which is far below the 1 μg/L defined by the World Health Organization provisional guideline for microcystin-LR. Finally, this method was successfully applied to lake water samples from Tai lake and proved to be useful for water quality monitoring.     

Construction of a dimethyl sulfoxide sensor based on dimethyl sulfoxide reductase immobilized on a au film electrode.

A novel dimethyl sulfoxide (DMSO) sensor using DMSO reductase and film electrodes was constructed. The Au and Ag electrodes were fabricated on slide glass by vacuum deposition and the application of a photolithographic technique. The micro-chamber (4 x 50 x 1 mm, volume 200 microl) was fabricated on a poly(dimethylsiloxane) (PDMS) polymer. The Pt electrode was implanted in a PDMS polymer. DMSO reductase was immobilized on a Au film electrode with bovine serum albumin (BSA)-glutaraldehyde. This sensor could determine DMSO in an unpurged aqueous solution with glucose oxidase (GOD) and catalase (CAT) for oxygen removal. The DMSO sensor showed a linear response within 1 mM DMSO with a correlation coefficient of 0.999. The detection limit was 200 microM (3sigma), and the sensitivity was 23.8 mA M(-1) cm(-2). The relative standard deviations at each concentration were within 3.6%.     

Simultaneous HPLC determination of thiocolchicoside and glafenine as well as thiocolchicoside and floctafenine in their combined dosage forms

Sensitive and accurate high-performance liquid chromatographic methods have been developed for the simultaneous determination of thiocolchicoside (TC)-glafenine (GF) (Mix I) and thiocolchicoside-floctafenine (FN) (Mix II) in their pharmaceutical formulations. The analysis for both mixtures was performed using 250 mm × 4.6 mm i.d., 5 μm particle size C18 Waters Symmetry column. The mobile phase consisted of methanol-0.035 M phosphate buffer (50:50, v/v) of pH 4.5 for Mix I and methanol-0.03 M phosphate buffer (70:30, v/v) of pH 4 for Mix II with flow rate of 1 mL/min and UV detection at 400 nm in both cases. The calibration plots were rectilinear over the concentration range of 0.2-2 μg/mL for TC in both mixtures and 20-200 μg/mL for each of GF and FN . The limits of detection for TC and GF were 0.05 μg/mL and 0.62 μg/mL, respectively, and for TC and FN were 0.02 μg/mL and 0.70 μg/mL, respectively. Additionally, the proposed methods were successfully applied to their combined tablets with average percentage recoveries of 100.35 ± 0.61 and 100.57 ± 0.72% for TC and GF respectively and for TC and FN the percentage recoveries were 101.2 ± 0.72 and 100.36 ± 0.67%, respectively. The results obtained were favorably compared with those given using the comparison methods.     

Enhancement of β-Glucan Biological Activity Using a Modified Acid-Base Extraction Method from Saccharomyces cerevisiae

Beta glucan (β-glucan) has promising bioactive properties. Consequently, the use of β-glucan as a food additive is favored with the dual-purpose potential of increasing the fiber content of food products and enhancing their health properties. Our aim was to evaluate the biological activity of β-glucan (antimicrobial, antitoxic, immunostimulatory, and anticancer) extracted from Saccharomyces cerevisiae using a modified acid-base extraction method. The results demonstrated that a modified acid-base extraction method gives a higher biological efficacy of β-glucan than in the water extraction method. Using 0.5 mg dry weight of acid-base extracted β-glucan (AB extracted) not only succeeded in removing 100% of aflatoxins, but also had a promising antimicrobial activity against multidrug-resistant bacteria, fungi, and yeast, with minimum inhibitory concentrations (MIC) of 0.39 and 0.19 mg/mL in the case of resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa, respectively. In addition, AB extract exhibited a positive immunomodulatory effect, mediated through the high induction of TNFα, IL-6, IFN-γ, and IL-2. Moreover, AB extract showed a greater anticancer effect against A549, MDA-MB-232, and HepG-2 cells compared to WI-38 cells, at high concentrations. By studying the cell death mechanism using flow-cytometry, AB extract was shown to induce apoptotic cell death at higher concentrations, as in the case of MDA-MB-231 and HePG-2 cells. In conclusion, the use of a modified AB for β-glucan from Saccharomyces cerevisiae exerted a promising antimicrobial, immunomodulatory efficacy, and anti-cancer potential. Future research should focus on evaluating β-glucan in various biological systems and elucidating the underlying mechanism of action.     

3D graphical representation of protein sequences and their statistical characterization

Based on three physicochemical properties of amino acid side chains, we proposed a novel unique 3D graphical representation of protein sequences. Then, we constructed two vectors of three components as mathematical objects to characterize protein sequences numerically. The similarity/dissimilarity analysis among nine ND5 protein sequences proved the utility of our approach. A correlation and significance analysis have been provided to compare our results and the sequence homology.