Solar Fuels: Photoelectrosynthesis of CO from CO2 at p‐Type Si using Fe Porphyrin Electrocatalysts

Photoelectrocatalytic conversion of CO₂ to CO can be driven at a boron‐doped, hydrogen terminated, p‐type silicon electrode using a meso‐tetraphenylporphyrin Fe^III chloride in the presence of CF₃CH₂OH as a proton source and 0.1 M [NBu₄][BF₄]/MeCN/5 % DMF (v/v) as the electrolyte. Under illumination with polychromatic light, the photoelectrocatalysis operates with a photovoltage of about 650 mV positive of that for the dark reaction. Carbon monoxide is produced with a current efficiency >90 % and with a high selectivity over H₂ formation. Photoelectrochemical current densities of 3 mA cm^?2 at ?1.1 V versus SCE are typical, and 175 turnovers have been attained over a 6 h period. Cyclic voltammetric data are consistent with a turnover frequency of ${k{{{\rm Si}\hfill \atop {\rm obs}\hfill}}}$ =0.24×10⁴ s^?1 for the photoelectrocatalysis at p‐type Si at ?1.2 V versus SCE this compares with ${k{{{\rm C}\hfill \atop {\rm obs}\hfill}}}$ =1.03×10⁴ s^?1 for the electrocatalysis in the dark on vitreous carbon at a potential of ?1.85 V versus SCE.     

The structure elucidation of the isomeric mixture of 3-[L-threo-2,3,4-tri -hydroxy-1-(phenyl-hydrazono)butyl] quinoxalin-2(1H)-one in dimethyl sulfoxide solution revisited: experimental and theoretical study

Structural Chemistry - Based on the analyses of 1D and 2D NMR spectra techniques, such as H–H COSY, HSQC, and HMBC of 3-[L-threo-2,3,4-trihydroxy-1-(phenylhydrazono)butyl]-...     

A new flexible strategy for the synthesis of gem-difluoro-bisarylic derivatives and heterocyclic analogues

A new strategy has been designed for the preparation of gem-difluoro-bisarylic derivatives. It starts from easily accessible and reactive gem-difluoro-propargylic intermediates and elaborates the aromatic rings by a Diels-Alder-aromatization sequence. Heterocyclic systems can be also obtained by 1,3 dipolar cycloadditions, affording mixed aromatic/heteroaromatic derivatives with CF₂ as a linker. Since this motif is a bioisostere of O and CO, corresponding bisarylic scaffolds could be of use to prepare chemical libraries of fluorinated analogues of bioactive natural products and/or drugs.     

Photoconductivities of Nanocrystalline Vanadium Pentoxide Thin Film Grown by Plasma RF Magnetron Sputtering at Different Conditions of Deposition

Physics of the Solid State - In this study, the fabrication and characterization of a metal–semiconductor–metal (MSM) visible photodetector based on V2O5 were investigated. The V2O5...     

Radiometric efficiency of analytical filters at different physical conditions

The radiometric efficiency of three analytical filters AFA-RSP-20, AFA-RMP-20 and AFA-RMV-20 was examined at different air velocities and aerosol number concentrations. An experimental setup had been constructed with 2 m³ radon chamber. Alpha radiometry was used to measure the deposited activities in the filters. Aerosols parameters like number concentration and size distribution are measured continuously with an aerosol diffusion spectrometer (ADS). RMV filter has a stable efficiency ~ 99.8%. The RSP and RMP filters efficiency is depending on the aerosol concentration and air sampling velocity. The effect of an aerosol concentration on the filter efficiency is more obvious than the effect of air velocity.

     

A generating equation for mixing rules and two new mixing rules for interatomic potential energy parameters

A generating equation for the mixing rules of interatomic potential energy parameters is proposed. It is demonstrated that this equation can, indeed, reproduce many popular mixing rules. A weighting matrix is used with the generating equation. This weighting matrix approach is superior to the present status of mixing rule development. A systematic framework is given for devising new mixing rules and/or comparing them. Two new mixing rules, which are more accurate than the available rules in the literature, are proposed. These rules are capable of reproducing the collision diameter and well-depth parameters for the binary values of noble gases to within their experimental uncertainties.     

Liquid crystalline polymers VII. Thermotropic liquid crystalline poly(azomethine-ether)s containing dibenzylidene derivatives in the main chain

A new homologous series of thermotropic liquid crystalline poly(azomethine-ether)s based on dibenzylidene derivatives was synthesized by solution polycondensation of various diformyl-α,ω-diphenoxyalkanes, I-VIII with 2,7-bis-(m-aminobenzylidene)cycloheptanone IX and bis-(m-aminobenzylidene)acetone X. The inherent viscosities of the polymers were in the range 0.23-0.69 dl/g. All the poly(azomethine-ether)s were insoluble in common organic solvents but dissolved completely in concentrated H₂SO₄ and methanesulphonic acid. The mesomorphic properties were studied as a function of the diphenoxyalkane space length. Analysis by differential scanning calorimetry and optical polarized microscopy demonstrated that the poly(azomethine-ether)s from nematic mesophases over wide temperature ranges.     

Spectrophotometric determination of clotrimazole and Phenylephrine-HCl in pharmaceutical formulation using 1, 2-naphthoquinone-4-Sulphonic acid sodium salt (NQS) as a chromogenic reagent

A sensitive, rapid and economical spectrophotometric method based on their interaction with NQS reagent in basic medium, which produces orange-colored complexes, has been devised to identify many drugs with amino groups (clotrimazole and phenylephrine-HCl). The maximum absorption for the complexes of clotrimazole and phenylephrine-HCl is 455 and 484 nm, respectively. Beer's law is applicable in the concentration ranges of (2–40) μg/ml for clotrimazole and (0–20) μg/ml for phenylephrine-HCl. The molar absorptivity values are 3931.1760 L/mol.cm and 4521.4074 L/mol.cm of clotrimazole and phenylephrine-HCl respectively with accuracy of 100.0285%–103.1456% and RSD better than 3.3211%. The method has been successfully used to determine these medications in pharmaceutical formulations, and it has been found to be superior to British Pharmacopeia standard procedures. At a 95% confidence level, F and t-tests are less than the tabulated values.     

Deciphering the Interactions of Bioactive Compounds in Selected Traditional Medicinal Plants against Alzheimer’s Diseases via Pharmacophore Modeling,Auto-QSAR,and Molecular Docking Approaches

Neurodegenerative diseases, for example Alzheimer’s, are perceived as driven by hereditary, cellular, and multifaceted biochemical actions. Numerous plant products, for example flavonoids, are documented in studies for having the ability to pass the blood-brain barrier and moderate the development of such illnesses. Computer-aided drug design (CADD) has achieved importance in the drug discovery world; innovative developments in the aspects of structure identification and characterization, bio-computational science, and molecular biology have added to the preparation of new medications towards these ailments. In this study we evaluated nine flavonoid compounds identified from three medicinal plants, namely T. diversifolia, B. sapida, and I. gabonensis for their inhibitory role on acetylcholinesterase (AChE), butyrylcholinesterase (BChE) and monoamine oxidase (MAO) activity, using pharmacophore modeling, auto-QSAR prediction, and molecular studies, in comparison with standard drugs. The results indicated that the pharmacophore models produced from structures of AChE, BChE and MAO could identify the active compounds, with a recuperation rate of the actives found near 100% in the complete ranked decoy database. Moreso, the robustness of the virtual screening method was accessed by well-established methods including enrichment factor (EF), receiver operating characteristic curve (ROC), Boltzmann-enhanced discrimination of receiver operating characteristic (BEDROC), and area under accumulation curve (AUAC). Most notably, the compounds’ pIC₅₀ values were predicted by a machine learning-based model generated by the AutoQSAR algorithm. The generated model was validated to affirm its predictive model. The best models achieved for AChE, BChE and MAO were models kpls_radial_17 (R² = 0.86 and Q² = 0.73), pls_38 (R² = 0.77 and Q² = 0.72), kpls_desc_44 (R² = 0.81 and Q² = 0.81) and these externally validated models were utilized to predict the bioactivities of the lead compounds. The binding affinity results of the ligands against the three selected targets revealed that luteolin displayed the highest affinity score of −9.60 kcal/mol, closely followed by apigenin and ellagic acid with docking scores of −9.60 and −9.53 kcal/mol, respectively. The least binding affinity was attained by gallic acid (−6.30 kcal/mol). The docking scores of our standards were −10.40 and −7.93 kcal/mol for donepezil and galanthamine, respectively. The toxicity prediction revealed that none of the flavonoids presented toxicity and they all had good absorption parameters for the analyzed targets. Hence, these compounds can be considered as likely leads for drug improvement against the same.     

The Regulation of Endoplasmic Reticulum Stress in Cancer: Special Focuses on Luteolin Patents

Cancer is a major health problem across the globe, and is expeditiously growing at a faster rate worldwide. The endoplasmic reticulum (ER) is a membranous cell organelle having inextricable links in cellular homeostasis. Altering ER homeostasis initiates various signaling events known as the unfolded protein response (UPR). The basic purpose of the UPR is to reinstate the homeostasis; however, a continuous UPR can stimulate pathways of cell death, such as apoptosis. As a result, there is great perturbation to target particular signaling pathways of ER stress. Flavonoids have gained significant interest as a potential anticancer agent because of their considerable role in causing cytotoxicity of the cancerous cells. Luteolin, a flavonoid isolated from natural products, is a promising phytochemical used in the treatment of cancer. The current study is designed to review the different endoplasmic reticulum stress pathways involved in the cancer, mechanistic insights of luteolin as an anticancer agent in modulating ER stress, and the available luteolin patent formulations were also highlighted. The patents were selected on the basis of pre-clinical and/or clinical trials, and established antitumor effects using patent databases of FPO IP and Espacenet. The patented formulation of luteolin studied so far has shown promising anticancer potential against different cancer cell lines. However, further research is still required to determine the molecular targets of such bioactive molecules so that they can be used as anticancer drugs.