Preparation and characterization of sulphur and zinc oxide Co-doped graphitic carbon nitride for photo-assisted removal of Safranin-O dye.

Recently, there has been significant interest in photocatalytic reactions involving graphitic carbon nitride (g-C3N4) due to its sp2-hybridized carbon and nitrogen content and it is an ideal candidate for blending with other materials to enhance performance. Here, we have synthesized and analyzed both doped and undoped g-C3N4 nanoparticles. Specifically, we co-doped sulfur (S) into g-C3N4, integrated it with ZnO particles, and investigated the photocatalytic potential of these nanocomposites to remove Safranin-O dye. The initial step involved the preparation of pure g-C3N4 through calcination of urea. Subsequently, S-g-C3N4 was synthesized by calcining a mixture of urea and thiourea with a 3 : 1 ratio. Finally, the ZnO-S-g-C3N4 composite was synthesized using the liquid exfoliation technique, with distilled water serving as the exfoliating solvent. These samples were characterized by advanced techniques, including UV-Vis spectroscopy, Fourier-transform infrared spectroscopy (FTIR), X-ray Diffraction (XRD), energy dispersive X-ray (EDX) and scanning electron microscopy (SEM), to assess their crystallinity, morphology, optical properties, and phase purity. Subsequently, these nanocomposites were employed in catalytic and photocatalytic processes to remove the Safranin-O dye (SO). The results highlighted the formation of Z-scheme junction responsible for ZnO-S-g-C3N4's significant performance improvement. The comparison of results demonstrated that S-g-C3N4 and ZnO-S-g-C3N4 composites revealed an effective removal of Safranin-O dye in the presence of UV-light as compared to pure g-C3N4, as it was attributed to the phenomenon of improved separation of photogenerated charge carriers as a result of heterojunction formation between S-g-C3N4 and ZnO interfaces. In addition to improving photocatalytic performance, this study presents a facile route for producing ZnO-S-g-C3N4 composite with superior adsorption capabilities and selectivity.

Natural Products as Bioactive Agents in the Prevention of Dementia.

Dementia is a complex syndrome of neurological disorders which is associated with cognitive functions of the body. The present review focuses on the role and application of natural products in the treatment of dementia and related diseases. The studies highlight that there exist some potent synthetic/semisynthetic drugs that can effectively target dementia and related diseases. In contrast, despite the existence of a large library of natural products, only a few of them (galantamine, huperzine A, etc.) have been approved as drugs against dementia. This fact is not discouraging because a large number of natural products, including classes of polyphenols, alkaloids, isothiocyanates, phytocannabinoids, and terpenoids, are in the process of drug development stages against dementia and related diseases. It is because they display some promising and diverse biological activities, including antioxidant, acetylcholinesterase inhibitory activity, and anti-amyloidogenic properties, which are significantly associated with the prevention of dementia syndrome. The studies reported in the literature reveal that bioactive natural products particularly target Alzheimer's and Parkinson's diseases by suppressing the risks responsible for dementia. Huperzine A has been identified as a potent natural product against Alzheimer's disease. Despite the efficient role of natural products in preventing dementia, their direct application as drugs is still limited due to some controversial results obtained from their clinical trials; however, bioassay-guided drug development studies can prove them potential drugs against dementia and related diseases. This review provides useful information for researchers, pharmacologists, and medical doctors.

The SARS-CoV-2 differential genomic adaptation in response to varying UVindex reveals potential genomic resources for better COVID-19 diagnosis and prevention.

Coronavirus disease 2019 (COVID-19) has been a pandemic disease reported in almost every country and causes life-threatening, severe respiratory symptoms. Recent studies showed that various environmental selection pressures challenge the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) infectivity and, in response, the virus engenders new mutations, leading to the emergence of more virulent strains of WHO concern. Advance prediction of the forthcoming virulent SARS-CoV-2 strains in response to the principal environmental selection pressures like temperature and solar UV radiation is indispensable to overcome COVID-19. To discover the UV-solar radiation-driven genomic adaption of SARS-CoV-2, a curated dataset of 2,500 full-grade genomes from five different UVindex regions (25 countries) was subjected to in-depth downstream genome-wide analysis. The recurrent variants that best respond to UV-solar radiations were extracted and extensively annotated to determine their possible effects and impacts on gene functions. This study revealed 515 recurrent single nucleotide variants (rcntSNVs) as SARS-CoV-2 genomic responses to UV-solar radiation, of which 380 were found to be distinct. For all discovered rcntSNVs, 596 functional effects (rcntEffs) were detected, containing 290 missense, 194 synonymous, 81 regulatory, and 31 in the intergenic region. The highest counts of missense rcntSNVs in spike (27) and nucleocapsid (26) genes explain the SARS-CoV-2 genomic adjustment to escape immunity and prevent UV-induced DNA damage, respectively. Among all, the most commonly observed rcntEffs were four missenses (RdRp-Pro327Leu, N-Arg203Lys, N-Gly204Arg, and Spike-Asp614Gly) and one synonymous (ORF1ab-Phe924Phe) functional effects. The highest number of rcntSNVs found distinct and were uniquely attributed to the specific UVindex regions, proposing solar-UV radiation as one of the driving forces for SARS-CoV-2 differential genomic adaptation. The phylogenetic relationship indicated the high UVindex region populating SARS-CoV-2 as the recent progenitor of all included samples. Altogether, these results provide baseline genomic data that may need to be included for preparing UVindex region-specific future diagnostic and vaccine formulations.

Micro-synteny conservation analysis revealed the evolutionary history of bacterial biphenyl degradation pathway.

Phenolic compounds have been enlisted by the United States Environmental Protection Agency (USEPA) and the European Union (EU) as pollutants of priority concern. The biphenyl degradation pathway plays an essential role in prokaryote polychlorinated biphenyls degradation. Our understanding of prokaryotic pathways and their evolution has dramatically increased in recent years with the advancements in prokaryotic genome sequencing and analysis tools. In this work, we applied bioinformatics tools to study the evolution of the biphenyl degradation pathway focusing on the phylogeny and initiation of four representative species (Burkholderia xenovorans LB400, Polaromonas naphthalenivorans CJ2, Pseudomonas putida F1 and Rhodococcus jostii RHA1). These species contained partial or full concatenated genes from bph gene cluster (i.e. bphRbphA1A2A3A4BCKHJID). The aim was to establish this pathway's origin and development mode in the prokaryotic world. Genomic screening revealed that many bacterial species possess genes for the biphenyl degradation pathway. However, the micro-synteny conservation analysis indicated that massive gene recruitment events might have occurred during the evolution of the biphenyl degradation pathway. Combining with the phylogenetic positions, this work points to the evolutionary process of acquiring the biphenyl degradation pathway by different fragments through horizontal gene transfer in these bacterial groups. This study reports the first-ever evidence of the birth of this pathway in the represented species.

Selection of active phase of MnO2 for catalytic ozonation of 4-nitrophenol.

Catalytic ozonation is a highly effective method in wastewater treatment, and MnO2 materials are widely recognized as active heterogeneous catalysts in this process. Many works reported the progress in active MnO2 synthesis, but the active phase is rarely systematically studied. In this paper, all six phases of MnO2 (α-, ß-, δ-, γ-, λ- and ε-) were synthesized by facile methods. Their catalytic activities in ozonation of 4-nitrophenol (4-NP) were evaluated and correlated with the physicochemical properties obtained from X-ray Diffraction (XRD), transmission electron microscopy (TEM), physical adsorption and cyclic voltammetry (CV) analysis. α- MnO2 was found to be the most active catalyst in 4-NP degradation at neutral pH. MnO2 with low average oxidation state (AOS) showed stronger oxidation/reduction peaks in CV characterization, which benefited catalytic decomposition of ozone to generate active species. Superoxide radical was confirmed as the main oxidizing species, along with singlet oxygen and ozone molecule oxidation in bulk solution and little contribution of oxidation on the MnO2 surface. Mn2+ leaching happened during catalytic ozonation, but its catalytic role is negligible. This result may give rise to the preparation of new active MnO2 catalysts.

Superoxide radical-mediated photocatalytic oxidation of phenolic compounds over Ag⁺/TiO2: Influence of electron donating and withdrawing substituents.

A comparative study was constructed to correlate the electronic property of the substituents with the degradation rates of phenolic compounds and their oxidation pathways under UV with Ag(+)/TiO2 suspensions. It was verified that a weak electron withdrawing substituent benefited photocatalytic oxidation the most, while an adverse impact appeared when a substituent was present with stronger electron donating or withdrawing ability. The addition of p-benzoquinone dramatically blocked the degradation, confirming superoxide radicals (O2(-)) as the dominant photooxidant, rather than hydroxyl radicals, singlet oxygen or positive holes, which was also independent of the substituent. Hammett relationship was established based on pseudo-first-order reaction kinetics, and it revealed two disparate reaction patterns between O2(-) and phenolic compounds, which was further verified by the quantum chemical computation on the frontier molecular orbitals and Mulliken charge distributions of O2(-) and phenolic compounds. It was found that electron donating group (EDG) substituted phenols were more likely nucleophilically attacked by O2(-), while O2(-) preferred to electrophilically assault electron withdrawing group (EWG) substituted phenols. Exceptionally, electrophilic and nucleophilic attack by O2(-) could simultaneously occur in p-chlorophenol degradation, consequently leading to its highest rate constant. Possible reactive positions on the phenolic compounds were also detailedly uncovered.

A novel process for recycling and resynthesizing LiNi1/3Co1/3Mn1/3O2 from the cathode scraps intended for lithium-ion batteries.

To solve the recycling challenge for aqueous binder based lithium-ion batteries (LIBs), a novel process for recycling and resynthesizing LiNi1/3Co1/3Mn1/3O2 from the cathode scraps generated during manufacturing process is proposed in this study. Trifluoroacetic acid (TFA) is employed to separate the cathode material from the aluminum foil. The effects of TFA concentration, liquid/solid (L/S) ratio, reaction temperature and time on the separation efficiencies of the cathode material and aluminum foil are investigated systematically. The cathode material can be separated completely under the optimal experimental condition of 15vol.% TFA solution, L/S ratio of 8.0 mL g(-1), reacting at 40°C for 180 min along with appropriate agitation. LiNi1/3Co1/3Mn1/3O2 is successfully resynthesized from the separated cathode material by solid state reaction method. Several kinds of characterizations are performed to verify the typical properties of the resynthesized LiNi1/3Co1/3Mn1/3O2 powder. Electrochemical tests show that the initial charge and discharge capacities of the resynthesized LiNi1/3Co1/3Mn1/3O2 are 201 mAh g(-)(1) and 155.4 mAh g(-1) (2.8-4.5 V, 0.1C), respectively. The discharge capacity remains at 129 mAh g(-1) even after 30 cycles with a capacity retention ratio of 83.01%.