Kinetics of the Reactions of Chlorinated Very Short-Lived Substances (VSLSs) with Chlorine Atoms

Chlorinated very short-lived substances (VSLSs), which are not controlled by the Montreal Protocol, are of current concern with regard to recovery of stratospheric ozone. Further study is needed on the temperature dependences of chlorinated VSLSs relevant to atmospheric conditions. Here, the kinetics of chlorinated VSLSs, such as chloroform (CHCl3), dichloromethane (CH2Cl2), dichloroethane (CH2ClCH2Cl), and trichloroethene (C2HCl3) reacting with chlorine atoms, were investigated between 180 and 400 K, expanding the range of temperatures relative to previous studies. RRKM/Master Equation and Canonical Variational Transition State Theory were utilized to calculate the rate coefficients using the MultiWell suite of programs. CCSD(T), QCISD(T), and M062X with aug-cc-pV(T+d)Z levels of theory were used to calculate the kinetic parameters. Arrhenius equations obtained from fits to the calculated rate coefficients are k1 = (2.66 ± 0.7) × 10-12 exp [(-927 ± 131)/T] cm3 molecule-1 s-1, k2 = (8.99 ± 0.3) × 10-12 exp [(-957 ± 19)/T] cm3 molecule-1 s-1, k3 = (1.51 ± 0.16) × 10-11 exp [(-714 ± 54)/T] cm3 molecule-1 s-1, and k4 = (9.17 ± 1.8) × 10-12 exp [(612 ± 101)/T] cm3 molecule-1 s-1 for the reactions of CHCl3, CH2Cl2, CH2ClCH2Cl, and C2HCl3 with Cl atoms, respectively. The rate coefficients for the reactions of chlorinated VSLSs with Cl atoms from this study are compared with the most recent recommended values from the NASA/JPL and IUPAC evaluations and with literature values. The reactivity trends of the reactions are discussed.

Porous chitosan-infused graphitic carbon nitride nanosheets for potential microbicidal and photo-catalytic efficacies

Supply of safe drinking water is a high-risk challenge faced internationally. Hybrid technologies involving nanomaterials can offer possible solutions to this research involving natural biopolymers. Porous chitosan with a high specific surface area has promising properties but its use as a membrane component in water purification is still rarely reported. Graphitic carbon nitride (g-C₃N₄) is a carbon nitride allotrope with a graphene-like layered structure that gifts unfamiliar physicochemical properties due to the presence of s-triazine fragments. It is a metal-free semiconductor with a band gap of ~2.7 eV to ~3.7 eV; which shows better visible light-activated photocatalyst properties. This work aims at synthesizing graphitic carbon nitride-biopolymer composite and exploring its properties in the field of wastewater treatment. The samples were synthesized via a soft chemical process with urea, as the source material. The flake-like morphology is displayed in the microstructural SEM image. The composition of the material was analyzed using EDS. Thermogram shows that the material is stable up to 500 °C and also confirms the formation of graphitic carbon nitride. In XRD spectra the intensity reduction shows the chitosan inclusion at the nitride site. The band gap of the prepared material was identified to be 2.3, 2.4 eV. The structural properties were analyzed using Fourier Transform Infrared Spectrometer and Raman spectroscopy. FTIR spectra and Raman spectra indicate the stretching vibration modes of CN and CN heterocycles and chitosan inclusion in the carbon nitride network. The photocatalytic activity was done in sunlight and a UV lamp with different dyes for doped and undoped g-C₃N₄. The doped (Porous/Non-porous chitosan) g-C₃N₄ showed faster dye degradation in sunlight compared to UV light. A biomolecular interaction study was done using Bovine serum albumin. It shows the material interaction with the BSA protein. The anti-microbial activity was performed on the Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli by disk diffusion method, the chitosan doped g-C₃N₄ showed good inhibitions against bacterial growth. The current work reveals the impact of nanoscale chitosan nanostructures doped on the optical, microstructural, catalytic, and antimicrobial properties of g-C₃N₄ nanosheets. This work provides new research options for nanocomposite-based photocatalytic nanomaterial g-C₃N₄ so that the quality of contaminated water could be improved.

TiO2 nanoparticles derived from egg shell waste: Eco synthesis, characterization, biological and photocatalytic applications

Biosynthesis of metal oxide nanoparticles has attracted much attention in recent years owing to the increasing impact for improving hygienic substances, cost effective approaches, environment friendly solvents and reusable resources. The present study has shown the eco synthesis of TiO₂ nanoparticles using the aqueous extract of egg shell waste. UV, XRD, FT-IR, and FE-SEM with EDX methods were implied for TiO₂ nanoparticles. The agar well approach was used to investigate the antimicrobial properties of biosynthesized nanoparticles against pathogenic organisms. The cytotoxicity analysis was investigated by MTT assay method and photocatalytic activity was studied using methylene blue, methyl orange and Congo red dye. X-ray diffraction studies showed that the presence of tetragonal structure. The crystallite size of synthesized TiO₂ nanoparticles is 27.3 nm. FE-SEM analysis indicates that the average grain size of the prepared sample was found to be in the range of 30-40 nm. Eco synthesis of TiO₂ nanoparticles displayed amazing antimicrobial efficacies against human pathogenic organisms and obtained excellent cytotoxicity investigation was performed against Osteosarcoma cell lines (MG-63). Further it was also found that the expression of impressive catalytic efficiency, 91.1 percent decreased in 60 min for methylene blue. From the results, we found that eco synthesized TiO₂ nanoparticles has promising utility in multidisciplinary like antimicrobial, anticancer and photocatalytic applications.

Assessment of spatial-temporal changes in water bodies and its influencing factors using remote sensing and GIS - a model study in the southeast coast of India

Concerns have been raised about the threat of ecological imbalance due to the loss of water bodies in densely populated areas. The present study explored the changes in water bodies in terms of area, number, and size in northern districts of Tamil Nadu, India, between 1978 and 2018 using satellite data, geographic information system, spatial analysis, ground truth verification, and field validation. The analysis indicated that the water bodies' area has reduced by 3027 ha and 4363 ha in the Kancheepuram and Tiruvallur Districts, respectively. Almost 179 water bodies have entirely disappeared, and 628 water bodies have been partly converted for other purposes. Of the disappeared water bodies, small, medium, and large water bodies account for 53, 93, and 33, respectively. The main reason for the changes in water bodies was the conversion to agriculture and buildings. Overall, the water bodies' area and number have been reduced by 9% and 12%, respectively, while the population has grown by 37%. The water bodies lost due to anthropogenic activities demand the scientific inventory of water bodies and integrated water resources management at a state or national level with strict monitoring regulations to protect them.

Anti-dengue Potential of Mangiferin: Intricate Network of Dengue to Human Genes

Dengue fever has become one of the deadliest infectious diseases and requires the development of effective antiviral therapies. It is caused by members of the Flaviviridae family, which also cause various infections in humans, including dengue fever, tick-borne encephalitis, West Nile fever, and yellow fever. In addition, since 2019, dengue-endemic regions have been grappling with the public health and socio-economic impact of the ongoing coronavirus disease 19. Co-infections of coronavirus and dengue fever cause serious health complications for people who also have difficulty managing them. To identify the potentials of mangiferin, a molecular docking with various dengue virus proteins was performed. In addition, to understand the gene interactions between human and dengue genes, Cytoscape was used in this research. The Kyoto Encyclopedia of Genes and Genomes software was used to find the paths of Flaviviridae. The Kyoto Encyclopedia of Genes and Genomes and the Reactome Pathway Library were used to understand the biochemical processes involved. The present results show that mangiferin shows efficient docking scores and that it has good binding affinities with all docked proteins. The exact biological functions of type I interferon, such as interferon-α and interferon-β, were also shown in detail through the enrichment analysis of the signaling pathway. According to the docking results, it was concluded that mangiferin could be an effective drug against the complications of dengue virus 1, dengue virus 3, and non-structural protein 5. In addition, computational biological studies lead to the discovery of a new antiviral bioactive molecule and also to a deeper understanding of viral replication in the human body. Ultimately, the current research will be an important resource for those looking to use mangiferin as an anti-dengue drug.

Raman and X-ray photoelectron spectroscopic investigation of solution processed Alq3/ZnO hybrid thin films

In this study, we characterize the solution processed tris-(8-hydroxyquinoline)aluminum(Alq₃)/ZnO hybrid thin films using Raman and X-ray photoelectron spectroscopic (XPS) techniques. Raman studies reveal the sol-gel derived spin-coated ZnO thin film has hexagonal wurtzite structure. The incorporation of Alq₃ molecules in the hybrid film results in the formation of bonding onto the surface of highly crystalline ZnO nanoparticles. The XPS confirms the incorporation of Alq₃ in the hybrid thin films and corroborates that the Alq₃ molecules may be adsorbed onto the surface of ZnO nanoparticles (chemisorption), showing the existence of chemical interaction between Alq₃ and ZnO in the hybrid films. These studies support that the chemisorbed Alq₃ molecules onto the ZnO nanoparticles may facilitate the charge transfer (non-radiative) between Alq₃ and ZnO in the hybrid thin films which will be useful to enhance the optical and electrical properties for the optoelectronic device applications.

Traditional uses, phytochemistry and pharmacology of Bauhinia racemosa Lam.: a comprehensive review

Background

Bauhinia racemosa is not familiarly known in Asian countries due to its limited existence and lack of medicinal information. It is commonly used as a medicine, ornamental plant, fence plant, and fodder for livestock since ancient times. It is also used as a landfill tree to avoid soil erosion of the forest.

Main body

In South India, people cultivate this plant in their premises in order to protect themselves from the effects of thunder. In this review, the various research prospects of this plant have been analyzed and are summarized. The aim of this review is to provide the traditional uses, phytochemicals and pharmacological activities of B. racemosa, and to highlight the current pharmacological developments of this medicinal plant.

Conclusions

The B. racemosa has immense therapeutic potential for treating diseases with both traditional and pharmacological applications. But many traditional uses of B. racemosa have not been validated by current investigations in the aspects of pharmaceutical. Until now, research on phyto-constituents from B. racemosa has not been done in an extensive way. Hence, the identified phytochemicals of B. racemosa should also be subjected to pharmacological studies to illuminate the biological mechanisms of these unreported secondary metabolites for the prevention of diseases or microbial infections and other health disorders of human and animal races.

Evolving Perceptions, Utilization, and Real-World Implementation Experiences of Oncology Monoclonal Antibody Biosimilars in the USA: Perspectives from Both Payers and Physicians

BACKGROUND

The adoption of oncology biosimilars has been slow in the USA, which may be attributed in part to stakeholder perceptions and lack of operational guidance that supports favorable access to biosimilars.

OBJECTIVE

Our objective was to understand the real-world implementation experiences with oncology biosimilars of US payers and healthcare professionals (HCPs) as their experience with biosimilars has evolved.

METHODS

In-depth qualitative interviews with payers (n = 20) and HCPs (n = 17 physicians, n = 3 practice managers) were conducted. Payers included managed care organizations (MCOs), integrated delivery networks, and pharmacy benefit managers (PBMs). Physicians were affiliated with a healthcare network or were community based, specialized in hematology/oncology, and had prescribed oncology biosimilars. Audio transcripts of the interviews were coded using MaxQDA software to enable descriptive analysis of the qualitative data.

RESULTS

Over 80.0% of physicians perceived the efficacy and safety of biosimilars to be highly comparable to that of originators. Up to 87.5% of physicians reported using biosimilars in > 50% of their treatment-naïve patients and were comfortable using biosimilars in all approved indications. To encourage utilization, 75.0% of MCOs/PBMs preferred biosimilars over originators in treatment-naïve patients and implementation via step therapy. Physician involvement in choosing biosimilars was minimal, which was largely dependent on practice protocols or insurance preferences. The major factor influencing payers' coverage decisions and biosimilar adoption was potential cost savings.

CONCLUSIONS

US payers and physicians who have experience with biosimilars have favorable views of oncology biosimilars, particularly for treatment-naïve patients. A framework for integrating biosimilars into oncology practice is developing, primarily driven by insurance coverage, contracting, and cost benefits.

Experimental and Computational Investigations of the Tropospheric Photooxidation Reactions of 1,1,1,3,3,3-Hexafluoro-2-Methyl-2-Propanol Initiated by OH Radicals and Cl Atoms

The gas-phase kinetics for the reactions of OH radicals and Cl atoms with 1,1,1,3,3,3-hexafluoro-2-methyl-2-propanol (HF2M2P) were measured at temperatures between 268 and 363 K using the relative rate experimental technique. Methane and acetonitrile were used as reference compounds to measure the rate coefficients of the title reactions. For the reactions of HF2M2P with OH radicals and Cl atoms, the rate coefficients were measured to be (7.07 ± 1.21) × 10^-15 and (2.85 ± 0.54) × 10^-14 cm³ molecule^-1 s^-1, respectively, at 298 K. The obtained Arrhenius expressions for the reactions of HF2M2P with OH radicals and Cl atoms are k_{HF2M2P + OH}^{Exp - (268 - 363 K)} = (7.84 ± 0.75) × 10^-14 exp [-(717 ± 59)/T] and k_{HF2M2P + Cl}^{Exp - (268 - 363 K)} = (3.21 ± 0.45) × 10^-12 exp [-(1395 ± 83)/T] cm³ molecule^-1 s^-1. In addition to the experimental measurements, computational kinetic calculations were also performed for the title reactions at the M06-2X/MG3S//M06-2X/6-31 + G(d,p) level of theory using advanced methods such as the canonical variational transition-state theory coupled with small curvature tunneling corrections at temperatures between 200 and 400 K. Theoretical calculations reveal that the H-abstraction from the CH₃ group is a more favorable reaction channel than that from the OH group. Thermochemistry, branching ratios, cumulative atmospheric lifetime, global warming potential, acidification potential, and photochemical ozone creation potential of HF2M2P were calculated in the present investigation.

Metal(loid)s (As, Hg, Se, Pb and Cd) in paddy soil: Bioavailability and potential risk to human health

Rice is one of the principal staple foods, essential for safeguarding the global food and nutritional security, but due to different natural and anthropogenic sources, it also acts as one of the biggest reservoirs of potentially toxic metal(loids) like As, Hg, Se, Pb and Cd. This review summarizes mobilization, translocation and speciation mechanism of these metal(loids) in soil-plant continuum as well as available cost-effective remediation measures and future research needs to eliminate the long-term risk to human health. High concentrations of these elements not only cause toxicity problems in plants, but also in animals that consume them and gradual deposition of these elements leads to the risk of bioaccumulation. The extensive occurrence of contaminated rice grains globally poses substantial public health risk and merits immediate action. People living in hotspots of contamination are exposed to higher health risks, however, rice import/export among different countries make the problem of global concern. Accumulation of As, Hg, Se, Pb and Cd in rice grains can be reduced by reducing their bioavailability, and controlling their uptake by rice plants. The contaminated soils can be reclaimed by phytoremediation, bioremediation, chemical amendments and mechanical measures; however these methods are either too expensive and/or too slow. Integration of innovative agronomic practices like crop establishment methods and improved irrigation and nutrient management practices are important steps to help mitigate the accumulation in soil as well as plant parts. Adoption of transgenic techniques for development of rice cultivars with low accumulation in edible plant parts could be a realistic option that would permit rice cultivation in soils with high bioavailability of these metal(loid)s.

A milestone in prediction of the coronary artery dimensions from the multiple linear regression equation

BACHGROUND /AIM

Coronary artery imaging is one of the most commonly used diagnostic methods. We aimed to investigate whether there is a correlation between left main coronary artery (LMCA), left anterior descending artery (LAD) and left circumflex artery (LCx) artery dimensions in normal cases and a possibility to express the coronary dimensions by multiple linear equations.

MATERIALS AND METHODS

Images of coronary angiograms of 925 normal cases selected from 3855 cases made up the study population (515 men and 410 women; age range, 30-75 years). The mean age of the patients was 55.50 ± 6.49 years. The mean body mass index was 24.79 ± 1.45 kg/m² (range, 31.30-21.26 kg/m²). The mean dimensions of LMCA, LAD and LCx were 4.18 ± 0.65 mm, 3.22 ± 0.63 mm and 3.07 ± 0.65 mm, respectively. Correlation between LMCA, LAD and LCx diameters was investigated. Multiple linear regression analysis was used to develop a model to elucidate the relationship between LMCA, LAD and LCx diameters.

RESULTS

There was a strong correlation between LMCA dimensions and LAD and LCx dimensions (r = 0.526**, p < 0.001* and r = 0.469**, p < 0.001*, respectively). The positive correlation indicated that a regression analysis can be carried out by incorporating the measurements. Coronary artery dimensions were gender specific.

CONCLUSION

The present study explored the possibility of explaining the relationship with the LMCA and its branches by multiple linear equations, which may then be used to estimate the reference diameter of a stenosed coronary artery when the other two arteries are normal.

Water vapor flux in tropical lowland rice

A field experiment was conducted at Indian Council of Agricultural Research-National Rice Research Institute, Cuttack, Odisha, India in the dry seasons of 2015 and 2016 to assess the water vapor flux (FH₂O) and its relationship with other climatic variables. The FH₂O and climatic variables were measured by an eddy covariance system and a micrometeorological observatory. Daily mean FH₂O during the dry seasons of 2015 and 2016 were 0.009-0.092 g m^-2 s^-1 and 0.014-0.101 g m^-2 s^-1, respectively. Seasonal average FH₂O was 14.6% higher in 2016 than that in 2015. Diurnal variation for FH₂O showed a bell-shaped curve with its peak at 13:30-14:00 Indian Standard Time (IST) in both the years. Carbon dioxide flux was found higher with rise in FH₂O. This relationship was stronger at higher vapor pressure deficit (VPD) (20 ≤ VPD ≤ 40 and VPD > 40 hPa). The FH₂O showed significant positive correlation with latent heat flux, net radiation flux, photosynthatically active radiation, air, water and soil temperatures, shortwave down and upwell radiations, maximum and minimum temperatures, evaporation, and relative humidity in both the years. Principal component analysis showed that FH₂O was very close to latent heat flux in both the years (Pearson correlation coefficient close to 1). The two-dimensional observation map of the principal component F1 and F2 showed the observations taken during the vegetative stage and panicle initiation stage, and flowering stage and maturity stage were closer to each other. It can be concluded that the most important climatic variables controlling the FH₂O were latent heat of vaporization, net radiation, air temperature, soil temperatures, and water temperature.

Antioxidant and nephroprotection activities of Combretum micranthum: A phytochemical, in-vitro and ex-vivo studies

Management of chronic renal failure is exceedingly expensive. Despite of encouraging experimental outcomes, there is a lack of potent nephroprotective drugable molecules in a clinics or market. To develop a nephroprotective phytomedicine, the present study was designed to do a literature survey on reported phytochemical and biological analysis of Combretum micranthum and to carry out chemoprofiling, in-vitro antioxidant and ex-vivo nephroprotective capacity of the title plant. The phytochemical and biological activity survey of C. micranthum has reveals the presence of many bioactive compounds such as flavonoids, terpenoids, steroids and alkaloids with many biological activities. Phytochemical investigation re-confirmed the presence of these compounds. Hydroalcoholic extract of C. micranthum (CM extract) showed a strong antioxidant activity by scavenging AAPH, DPPH, nitric oxide, hydrogen peroxide and chelating metal ions. CM extract exhibited significant (P < 0.001) dose dependent inhibition of ferric chloride-ascorbic acid induced lipid peroxidation. Diabetic nephropathy is a serious and common complication leading to end stage renal disease. Therefore, in the present study, glucose-induced toxicity was also studied in human embryonic kidney cells (HEK-293) as an in vitro model for diabetic nephropathy. The results showed that exposure of cells to high glucose (100 mM) for 72 h significantly reduced the cell viability resulting in morphological changes such as cell shrinkage, rounded cell shape and cytoplasmic vacuolation. Treatment with CM extract at 10 and 25 μg/mL resulted in significant improvement in cell viability from 10 to 23% compared to the high glucose control. This study demonstrated the potential antioxidant and nephroprotective properties of C. micranthum, justifying its traditional use in the treatment of various diseases.

Structural insights into the anti-cancer activity of quercetin on G-tetrad, mixed G-tetrad, and G-quadruplex DNA using quantum chemical and molecular dynamics simulations

Human telomerase referred as 'terminal transferase' is a nucleoprotein enzyme which inhibits the disintegration of telomere length and act as a drug target for the anticancer therapy. The tandem repeating structure of telomere sequence forms the guanine-rich quadruplex structures that stabilize stacked tetrads. In our present work, we have investigated the interaction of quercetin with DNA tetrads using DFT. Geometrical analysis revealed that the influence of quercetin drug induces the structural changes into the DNA tetrads. Among DNA tetrads, the quercetin stacked with GCGC tetrad has the highest interaction energy of -88.08 kcal/mol. The binding mode and the structural stability are verified by the absorption spectroscopy method. The longer wavelength was found at 380 nm and it exhibits bathochromic shift. The findings help us to understand the binding nature of quercetin drug with DNA tetrads and it also inhibits the telomerase activity. Further, the quercetin drug interacted with G-quadruplex DNA by using molecular dynamics (MD) simulation studies for 100 ns simulation at different temperatures and different pH levels (T = 298 K, 320 K and pH = 7.4, 5.4). The structural stability of the quercetin with G-quadruplex structure is confirmed by RMSD. For the acidic condition (pH = 5.4), the binding affinity is higher toward G-quadruplex DNA, this result resembles that the quercetin drug is well interacted with G-quadruplex DNA at acidic condition (pH = 7.4) than the neutral condition. The obtained results show that quercetin drug stabilizes the G-quadruplex DNA, which regulates telomerase enzyme and it potentially acts as a novel anti-cancer agent.Communicated by Ramaswamy H. Sarma.