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The photocatalytic degradation of environmentally non-benign, toxic organic pollutants such as bisphenol A (BPA), brilliant green (BG), or mixture of dyes have been carried out using g-C3N4-TiO2 (GNT) nanocomposites. The GNT nanocomposites were synthesized by using hydrothermal method with different compositions and these nanocomposites were characterized using the different techniques. X-ray diffraction revealed that the anatase phase of TiO2 has been retained in composites; while characteristic reflection of g-C3N4 at 27.07° (d = 3.22 Å) is not observed due to its lower content in the nanocomposites. Raman spectra confirms the formation of composites between TiO2 with g-C3N4. Furthermore nano-scale dimensions of the bare or composites have been proved by FE-SEM and HR-TEM analysis. X-ray photoelectron spectroscopy (XPS) shows the presence of C, N, Ti and O as a constituents, with peaks due to CC, NCN of g-C3N4. Among the different nanocomposites, g-C3N4-TiO2 catalyst having 30% g-C3N4 and 70% TiO2 in molar proportion (i.e. 30-GNT) is exhibiting the highest efficiency for degradation of the different dyes in correlation to its higher surface area, lower optical band gap as well as more visible-light absorption (i.e., λ > 400 nm) in the electromagnetic spectrum. Keywords: Nanocomposites, TiO2, g-C3N4, Photocatalytic degradation, Bisphenol A, Brilliant green

Hydrothermal technique was employed for the synthesis of N- and B-codoped TiO2 at different atomic percentages and calcination temperatures (350 and 400 °C). Borane tert-butylamine complex was used as a novel precursor for the dopant atoms. The photocatalytic activities of catalysts were evaluated for destruction of bisphenol A (BPA) spiked in clean water and in secondary treated wastewater influent (SWI) collected from the Groundwater Replenishment System GWRS (Orange County, CA, USA), the world's largest water purification system for indirect potable reuse. Results of X-ray photoelectron spectroscopy (XPS) revealed the incorporation of N and B atoms onto TiO2 lattice via substitution of O and/or Ti, and interstitial incorporation mechanisms. Carbon doping (graphite-like carbon; O-C = O) was also evidenced from XPS spectra. X-ray diffraction (XRD) and high-resolution transmission electron microscopy (HR-TEM) revealed pristine TiO2 and all doped TiO2 existed in anatase structure. The anatase phase of catalysts was further confirmed by simulation of selected area electron diffraction (SAED) of the catalysts and reported anatase TiO2 using the simulation software CrysTBox (v 1.10). Among all prepared catalysts, 2.0NBT-350 (N + B = 2.0%, calcination = 350 °C) possessed the smallest particle size (12.9 nm), largest BET surface area (108.5 m2/g) and highest visible-light absorption (i.e., λ > 400 nm). Simulated solar light/2.0NBT-350 system exhibited the maximum removal of BPA (0.1 μM) at the optimum catalyst dose of 0.8 g/L in clean water, over three consecutive degradation reuse cycles without any noticeable decrease in its photocatalytic activity. BPA was also successfully removed in SWI water, however with slower kinetics due to hydroxyl radical quenching effect of dissolved organic and inorganic species present in the SWI matrix. Degradation byproducts were identified by LC/Q-TOF-ESI-MS analysis. Six byproducts were found in the reaction mixture, with two compounds were newly identified in the current study. BPA oxidation routes comprised successive BPA hydroxylation, elimination of aromatic ring, ring opening, and cyclization of aliphatic compounds. This study is a promising demonstration for controlled design and synthesis of photocatalysts useful for environmental applications, especially for the treatment of BPA in wastewater effluents.

Iodine-doped TiO2 nanoparticles (I@TiO2 NPs), in different mol percentage (mol%) of iodine with anatase phase only, have been prepared by using simple sol-gel method. Samples were characterized by various physico-chemical techniques. Physico-chemical characterization revealed that crystallite size, surface hydroxylation, and tuning of optical band gap towards visible region of composites increases with increase in dopant concentration upto 7.0 mol% in TiO2 host lattice. Thereafter, the samples were used to photocatalytic degradation of textile effluent (TE) as well as Rhodamine B (RhB) under sunlight irradiation directly. The progress of photodegradation reaction was monitored by UV–visible spectroscopy. The chemical oxygen demand (COD) of TE samples was evaluated before and after photocatalytic studies. During photocatalytic reaction, the effect of pH and amount of catalyst on the rate of degradation reaction was also studied. It is clearly shown that I@TiO2 particles result in the enhancement of the degradation ability of RhB as well as TE in sunlight.

ABBV-075 (Mivebresib) analogues were reported to have BET family bromodomain binding affinity Ki in nano-molar (nM) range (0.8 to 3000 nM). But future optimizations are required to achieve a drug-like molecule with retention of high binding affinity and optimum ADMET (Absorption, Distribution, Metabolism, Excretion and Toxicity) profile. This could be achieved by identifying the pharmacophoric features (salient and concealed) using modern techniques like CADD (Computer-Aided Drug Designing). Therefore, in the present work, QSAR (Quantitative structure-activity relationship) analysis, a thriving CADD branch, has been executed to achieve the determined objectives. The developed QSAR model is statistically acceptable with robust fitting, high internal and external predictive ability. The developed model fulfils the threshold values for a good number of statistical parameters like R2 = 0.80, R2CV = 0.77, etc. The analysis reveals that non-ring Carbon/Nitrogen atoms, frequency of occurrence of specific combinations of Carbon/Nitrogen atoms with acceptor/donor atoms are important pharmacophoric features for BET binding affinity. Thus, the developed QSAR has a balance of quantitative and qualitative approaches. The results could be useful for future optimizations of Mivebresib analogues .

Ta2O5, Ta2O5–SrO and Ta2O5–TiO2 photocatalysts were prepared by hydrothermal method and characterized using X-ray diffraction (XRD), Ultraviolet-visible Diffuse Reflectance spectroscopy (UV-Vis DRS) and Thermogravimetry (TGA). In synthesized series of TiO2-Ta2O5 catalysts, formation of anatase TiO2, hexagonal Ta2O5 and titanium tantalates were observed. For Ta2O5-SrO (Ta:Sr= 1:1) formation of mixed oxide and crystallinity was observed at calcinations temperature at 1100 °C (5hr). These synthesized catalysts were used for degradation study of methylene blue. The result demonstrated that the photocatalytic activity of the mixed oxides [Ta2O5-TiO2(1:1), Ta2O5-TiO2(2:1), Ta2O5-TiO2(1:2), Ta2O5-SrO (Ta:Sr= 1:1)] was higher than that of Ta2O5 alone.

Nitrogen-doped TiO 2 nanoparticles (N–TiO 2 NPs) with anatase phase were synthesized by sol–gel method using a single precursor containing titanium (IV) terbutoxide, glacial acetic acid, sodium dodecyl sulphate, ammonia, and urea. X-ray diffraction (XRD) reveals the nanocrystalline nature with anatase phase of all the samples. The particle size of all samples was found in the range of 5–12 nm using transmission electron microscopy (TEM). UV–visible absorption measurements examined that the optical band gap of the doped samples decrease with increase in dopant concentration from 0.0 to 7.0 mol%. Field-emission scanning electron microscopy (FESEM) with energy dispersive atomic X-ray (EDAX) spectroscopy was employed to analyse the morphology and chemical composition of these N–TiO 2 NPs. The photocatalytic activity of bare/doped TiO 2 samples was demonstrated for the degradation of Rhodamine B (RhB) dye under direct sunlight irradiation. The photocatalytic degradation was monitored by measuring the kinetic parameters based on UV–visible spectroscopy as well as the chemical oxygen demand (COD) during the course of the reaction. The effect of dye concentration and pH of the solution on the photocatalytic degradation reaction in the presence of colloidal bare/doped TiO 2 were also studied. The N–TiO 2 catalyst, with a nitrogen concentration of 7.0 mol%, showed the highest activity for photocatalytic mineralization of dye at acidic or alkaline medium than neutral condition under solar light irradiation directly.

In the present work, an extensive QSAR (Quantitative Structure Activity Relationships) analysis of a series of peptide-type SARS-CoV main protease (MPro) inhibitors following the OECD guidelines has been accomplished. The analysis was aimed to identify salient and concealed structural features that govern the MPro inhibitory activity of peptide-type compounds. The QSAR analysis is based on a dataset of sixty-two peptide-type compounds which resulted in the generation of statistically robust and highly predictive multiple models. All the developed models were validated extensively and satisfy the threshold values for many statistical parameters (for e.g. R2 ​= ​0.80–0.82, Q2loo ​= ​0.74–0.77, Q2LMO ​= ​0.66–0.67). The developed QSAR models identified number of sp2 hybridized Oxygen atoms within seven bonds from aromatic Carbon atoms, the presence of Carbon and Nitrogen atoms at a topological distance of 3 and other interrelations of atom pairs as important pharmacophoric features. Hence, the present QSAR models have a good balance of Qualitative (Descriptive QSARs) and Quantitative (Predictive QSARs) approaches, therefore useful for future modifications of peptide-type compounds for anti- SARS-CoV activity., Highlights • QSAR models have been built using easily interpretable descriptors. • QSAR models have excellent external predictive ability. • Identification salient and hidden pharmacophoric features. • First ever attempt to develop QSAR models for anti-SARS-Cov activity of peptide-type compounds.