Tandem Reactions of Electrophilic Indoles toward Indolizines and Their Subsequent Transformations through Pd(II)-Mediated C-H Functionalization to Access Polyring-Fused N-Heterocycles

A simple and efficient synthetic approach for generating a library of structurally novel indolizines has been developed via sequential 1,3-dipolar cycloaddition-ring opening processes. Using this methodology, a series of indolizines bearing different substituents were made in moderate to good yields. The presence of two functionalizable C-H bonds in these indolizine motifs makes them attractive for accessing fused indolizine scaffolds. In this line, we have introduced palladium-mediated site-selective C-H functionalizations, where the N-center and the two C-H centers of the indolizine moiety can be readily functionalized to generate fused N-heterocycles. Utilizing a Pd-mediated dual C-H activation of 5-benzoyl-substituted indolizine afforded 6H-indeno-indolizine, and a tetracene, viz., indolizino[2,1-b]indoles, was produced in the same substrate by the Pd-catalyzed selective C-H amination in the presence of oxygen.

Design, synthesis and evaluation of new thiazolidin-4-ones as LPA1 receptor antagonists for breast cancer therapy

Aim: Breast cancer has been a leading cause of mortality among women worldwide in recent years. Targeting the lysophosphatidic acid (LPA)-LPA1 pathway using small molecules could improve breast cancer therapy. Materials & methods: Thiazolidin-4-ones were developed and tested on MCF-7 cancer cells, and active compounds were analyzed for their effects on apoptosis, migration angiogenesis and LPA1 protein and gene expression. Results & conclusion: Compounds TZ-4 and TZ-6 effectively reduced the migration of MCF-7 cells, and induced apoptosis. TZ-4, TZ-6, TZ-8 and TZ-14 significantly reduced the LPA1 protein, LPA1 and angiogenesis gene expression in treated MCF-7 cells. Molecular docking and molecular dynamic simulation studies reveal the ligand interactions and stability of the LPA1-ligand complex. Developed thiazolidin-4-ones showed great potential as an LPA1-targeted approach to combating breast cancer.

Thermal performance study of a PV-driven innovative solar dryer with and without sensible heat storage for drying of Garcinia Pedunculata

Uneven drying is the key drawback of a conventional multi-tray dryer. Therefore, an improved active solar dryer with and without integrated sensible heat storage (SHS) was proposed. A unique feature of this dryer is its movable walls from the sides of the dryer to transform it to an indirect or mixed-mode as and when necessary. Garcinia Pedunculata (GP) is a local seasonal medicinal fruit in Northeast India. Drying kinetics of GP, the dryer performance and economic analysis of dryer were evaluated in the indirect solar dryer without SHS (Exp. I), mixed-mode solar dryer without SHS (Exp. II), indirect solar dryer with SHS (Exp. III), mixed-mode solar dryer with SHS (Exp. IV), and open sun drying (OSD). The dryer's average efficiencies were 18.12%, 22.37%, 21.74%, and 24.46% for Exp. I, Exp. II, Exp. III, and Exp. IV, respectively. The moisture content of GP was reduced to 12.09% in wet basis (w.b.) from 87.99% (w.b.). The overall drying time for Exp. I, Exp. II, OSD, Exp. III and Exp. IV were 31, 26, 53, 28, and 10 h, respectively. From the eleven drying models, the Two-Term model was the best-fitted model for Exp. I, Exp. II, OSD and Exp. III, and Midilli and Kucuk model was for Exp. IV. The final product's fragrance and colour are better for Exp. IV. Developing this dryer for Exp. I, Exp. II, Exp. III and Exp. IV, the price required was around 25,000, 27,000, 26,000, and 28,000 INR (1 US$ = 74.57 INR), respectively, while the economic payback periods are 1.6 years, 0.9 year, 1.4 years, and 0.59 year, respectively.

Characterization of Hydrothermally Decomposed and Synthesized CaCO3 Reinforcement from Dead Snail Shells

The development of new materials from marine resources presents a significant challenge due to the complexity of the associated materials and biology technologies. During this work, the snail shell, which naturally increases in thickness over time to protect the snail, has been identified as one of them. In this study, we investigated the use of powdered snail shells as a potential alternative to ceramics in the creation of customized composites. Our main objective is to explore the hydrothermal decomposition of the snail shell powder to remove undesirable components. To achieve this, we crushed and ground-washed dead snail shells and subjected them to hydrothermal decomposition using an autoclave and furnace at a temperature of 200, 220, 250, or 300 °C. We then analyzed the resulting samples using scanning electron microscope/energy-dispersive X-ray spectroscopy (SEM/EDS) and X-ray diffraction (XRD) techniques to determine changes in their composition and structure. Our findings demonstrate that all samples contained the elements Ca, C, and O, as confirmed by SEM/EDS results. XRD results show that hydrothermal decomposition at 250 °C led to good crystallization with maximum peak intensities observed at various diffraction angles. This indicates that the resulting material may have promising properties for use in composite materials. Overall, our study provides valuable insights into the use of snail shell powder as a potential material source for customized composites. Future studies could explore the optimization of the hydrothermal decomposition process and investigate the mechanical properties of the resulting materials to further develop this promising avenue of research.

A Computational Investigation on Chitosan Derivatives using Pharmacophore- based Screening, Molecular Docking, and Molecular Dynamics Simulations against Kaposi Sarcoma

BACKGROUND

Cancer is one of the most dangerous illnesses to the human body due to its severity and progressive nature. Kaposi's Sarcoma (KS) tumor can appear as painless purple spots on the legs, foot, or face. This cancer develops in the lining of lymph arteries and blood vessels. Along with the enlargement of lymph nodes, the vaginal region and the mouth portion are the additional target areas of KS. DNA-binding proteins known as Sox proteins are found in all mammals and belong to the HMG box superfamily. They controlled a wide range of developmental procedures, such as the formation of the germ layer, the growth of organs, and the selection of the cell type. Human developmental abnormalities and congenital illnesses are frequently caused by the deletion or mutation of the Sox protein.

AIM

The purpose of this study is to determine the promising Kaposi's sarcoma inhibitors through computational studies.

OBJECTIVE

In this present study computational approaches were used to evaluate the anti- carcinogenic efficacy against Kaposi's sarcoma.

METHODS

Ligand-based pharmacophore screening was performed utilising four different chemical libraries (Asinex, Chembridge, Specs, and NCI Natural products (NSC)) depending on the top hypothesis. The top hits were examined using molecular docking, absorption, distribution, metabolism and excretion. Highest occupied molecular orbital and lowest unoccupied molecular orbital were analysed to determine the lead compounds' biological and pharmacological efficacy. The results of the study indicated that the leading candidates were possible SOX protein inhibitors.

RESULTS

A pharmacophore model to inhibit the production of SOX protein in Kaposi Sarcoma was generated in this computational experiment using a set of 19 Chitosan compounds.

CONCLUSION

The results revealed that the top hits responded to all of the pharmacological druglikening criteria and had the best interaction residues, fitness scores, and docking scores. The resulting leads might be potential Kaposi's Sarcoma alternative treatments.

Unveiling the chemistry of 1,3,4-oxadiazoles and thiadiazols: A comprehensive review

Oxadiazoles and thiadiazoles are malleable heterocycles that have recently generated major interest in the field of medicinal chemistry. Compounds based on these moieties have versatile biological applications such as anticonvulsant, anticancer, antidiabetic, and antioxidant agents. Due to the versatile nature and stability of the oxadiazole and thiadiazole nucleus, medicinal chemists have changed the structural elements of the ring in numerous ways. These compounds have shown significant anticonvulsant effects, demonstrating their potential in the management of epileptic disorders. In this review, we have covered numerous biological pathways and in silico targeted proteins of oxadiazole and thiadiazole derivatives for treating various biological disorders. The data compiled in this article will be helpful for researchers, research scientists, and research chemists who work in the field of drug discovery and drug development.

Targeted Delivery of 5-Fluorouracil and Sonidegib via Surface-Modified ZIF-8 MOFs for Effective Basal Cell Carcinoma Therapy

The therapeutic effectiveness of the most widely used anticancer drug 5-fluorouracil (5-FU) is constrained by its high metabolism, short half-life, and rapid drug resistance after chemotherapy. Although various nanodrug delivery systems have been reported for skin cancer therapy, their retention, penetration and targeting are still a matter of concern. Hence, in the current study, a topical gel formulation that contains a metal-organic framework (zeolitic imidazole framework; ZIF-8) loaded with 5-FU and a surface modified with sonidegib (SDG; acting as a therapeutic agent as well as a targeting ligand) (5-FU@ZIF-8 MOFs) is developed against DMBA-UV-induced BCC skin cancer in rats. The MOFs were prepared using one-pot synthesis followed by post drug loading and SDG conjugation. The optimized MOFs were incorporated into hyaluronic acid-hydroxypropyl methyl cellulose gel and further subjected to characterization. Enhanced skin deposition of the 5-FU@ZIF-8-SDG MOFs was observed using ex vivo skin permeation studies. Confocal laser microscopy studies showed that 5-FU@ZIF-8-SDG MOFs permeated the skin via the transfollicular pathway. The 5-FU@ZIF-8-SDG MOFs showed stronger cell growth inhibition in A431 cells and good biocompatibility with HaCaT cells. Histopathological studies showed that the efficacy of the optimized MOF gels improved as the epithelial cells manifested modest hyperplasia, nuclear pleomorphism, and dyskeratosis. Additionally, immunohistochemistry and protein expression studies demonstrated the improved effectiveness of the 5-FU@ZIF-8-SDG MOFs, which displayed a considerable reduction in the expression of Bcl-2 protein. Overall, the developed MOF gels showed good potential for the targeted delivery of multifunctional MOFs in topical formulations for treating BCC cancer.

Antibody-conjugated nanoparticles for target-specific drug delivery of chemotherapeutics

Nanotechnology provides effective methods for precisely delivering chemotherapeutics to cancer cells, thereby improving efficacy and reducing off-target side effects. The targeted delivery of nanoscale chemotherapeutics is accomplished by two different approaches, namely the exploitation of leaky tumor vasculature (EPR effect) and the surface modification of nanoparticles (NPs) with various tumor-homing peptides, aptamers, oligonucleotides, and monoclonal antibodies (mAbs). Because of higher binding affinity and specificity, mAbs have received a lot of attention for the detection of selective cancer biomarkers and also for the treatment of various types of cancer. Antibody-conjugated nanoparticles (ACNPs) are an effective targeted therapy for the efficient delivery of chemotherapeutics specifically to the targeted cancer cells. ACNPs combine the benefits of NPs and mAbs to provide high drug loads at the tumor site with better selectivity and delivery efficiency. The mAbs on the NP surfaces recognize their specific receptors expressed on the target cells and release the chemotherapeutic agent in a controlled manner. Appropriately designed and synthesized ACNPs are essential to fully realize their therapeutic benefits. In blood stream, ACNPs instantly interact with biological molecules, and a protein corona is formed. Protein corona formation triggers an immune response and affects the targeting ability of the nanoformulation. In this review, we provide recent findings to highlight several antibody conjugation methods such as adsorption, covalent conjugation, and biotin-avidin interaction. This review also provides an overview of the many effects of the protein corona and the theranostic applications of ACNPs for the treatment of cancer.

SAM C-GAN: a method for removal of face masks from masked faces

The past years of COVID-19 have attracted researchers to carry out benchmark work in face mask detection. However, the existing work does not focus on the problem of reconstructing the face area behind the mask and completing the face that can be used for face recognition. In order to address this problem, in this work we have proposed a spatial attention module-based conditional generative adversarial network method that can generate plausible images of faces without masks by removing the face masks from the face region. The method proposed in this work utilizes a self-created dataset consisting of faces with three types of face masks for training and testing purposes. With the proposed method, an SSIM value of 0.91231 which is 3.89% higher and a PSNR value of 30.9879 which is 3.17% higher has been obtained as compared to the vanilla C-GAN method.

Validated HPLC method for ceftriaxone from dried blood spots for pharmacokinetic studies and therapeutic drug monitoring in neonatal population

Background: Pharmacokinetic evaluation is essential for the precise dosing of ceftriaxone in neonates. There is a need for developing a sensitive, affordable and convenient analytical method that can estimate ceftriaxone from dried blood spot (DBS) samples of neonates. Method: An HPLC-UV method was developed and validated as per ICH M10 for ceftriaxone from DBS and plasma using an Inertsil-ODS-3V column with gradient elution. DBS samples were extracted with methanol. Clinical validation was performed using neonatal samples. Results: The developed plasma- and DBS-based-HPLC method were linear from 2-700 μg/ml and 2-500 μg/ml, respectively, for ceftriaxone. Bland-Altman analysis indicated a strong interconvertibility between the plasma and DBS assays. Conclusion: Observed concentrations in clinical samples were comparable to the predicted concentrations, proving the clinical validity of the method.

Effect of pressure and time on bioactive content, PPO inactivation, physicochemical and sensory properties of aonla (Emblica officinalis) juice during hydrodynamic cavitation processing

Physical and nutritional attributes of aonla juice treated with hydrodynamic cavitation (HC) at a pressure range of 5-15 psi and time between 5 to 30 min were evaluated. Based on maximum retention of bioactives, antioxidant activity, inactivation of polyphenol oxidase (PPO), and physicochemical properties, HC conditions were optimized at 10 psi for 15 min, based on retention of 92.19% antioxidant activity, 88.01% vitamin C, and 96.80% of total phenolic content. Improved sedimentation index and viscosity were noted due to HC processing. The color profile of HC-treated samples was improved with less browning (63.86) and yellowing index (14.79) than that of control (browning index 64.61). Thermally treated samples inactivated 100% of PPO at 95 ℃ for 3 min, however, formation of a dark color with a browning index value of 67.38 was noted. The retention of various bioactives in thermally treated juice samples was much lesser than that of HC-treated samples.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10068-022-01164-2.

Structural Insights into N-heterocyclic Moieties as an Anticancer Agent against Hepatocellular Carcinoma: An Exhaustive Perspective

Hepatocellular carcinoma (HCC) is rapidly spreading around the world with a high mortality rate. In the low- and middle-income nations most impacted by HCV and HBV infections, HCC places a significant strain on the healthcare system and leaches productive capability. An extensive study on HCC to create novel therapeutic approaches was motivated by the lack of adequate preventive or curative therapy methods. Several medications have been put forward and some drug molecules are under investigation by the Food and Drug Administration (FDA) for the treatment of HCC. However, these therapeutic choices fall short of the ideal due to toxicity and the rapid rise in drug resistance which decreases the efficacy of these therapeutics and leads to the severity of hepatocellular carcinoma. Therefore, concerning these problems, there is a critical need for novel systemic combination therapies as well as novel molecular entities that target various signalling pathways, reducing the likelihood that cancer cells may develop treatment resistance. In this review, we discuss the conclusions of several studies suggesting that the N-heterocyclic ring system is a key structural component of many synthetic drugs with a diverse range of biological activities. Following nuclei, such as pyridazine, pyridine, and pyrimidines, along with benzimidazole, indole, acridine, oxadiazole, imidazole, isoxazole, pyrazole, quinolines, and quinazolines, have been included to provide a general overview of the link between structure and activity between heterocyclics and their derivatives against hepatocellular carcinoma. A comprehensive investigation of the structure-activity relationship between the series may be done by the direct comparison of anticancer activities with the reference.

Implication of in silico studies in the search for novel inhibitors against SARS-CoV-2

Corona Virus Disease-19 (COVID-19) is a pandemic disease mainly caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). It had spread from Wuhan, China, in late 2019 and spread over 222 countries and territories all over the world. Earlier, at the very beginning of COVID-19 infection, there were no approved medicines or vaccines for combating this disease, which adversely affected a lot of individuals worldwide. Although frequent mutation leads to the generation of more deadly variants of SARS-CoV-2, researchers have developed several highly effective vaccines that were approved for emergency use by the World Health Organization (WHO), such as mRNA-1273 by Moderna, BNT162b2 by Pfizer/BioNTech, Ad26.COV2.S by Janssen, AZD1222 by Oxford/AstraZeneca, Covishield by the Serum Institute of India, BBIBP-CorV by Sinopharm, coronaVac by Sinovac, and Covaxin by Bharat Biotech, and the first US Food and Drug Administration-approved antiviral drug Veklury (remdesivir) for the treatment of COVID-19. Several waves of COVID-19 have already occurred worldwide, and good-quality vaccines and medicines should be available for ongoing as well as upcoming waves of the pandemic. Therefore, in silico studies have become an excellent tool for identifying possible ligands that could lead to the development of safer medicines or vaccines. Various phytoconstituents from plants and herbs with antiviral properties are studied further to obtain inhibitors of SARS-CoV-2. In silico screening of various molecular databases like PubChem, ZINC, Asinex Biol-Design Library, and so on has been performed extensively for finding effective ligands against targets. Herein, in silico studies carried out by various researchers are summarized so that one can easily find the best molecule for further in vitro and in vivo studies.

Synthesis of diamond crystal growth on tungsten carbide inserts by HFCVD using various seeding powders

The hot filament chemical vapor deposition (HFCVD) process is used to synthesize diamond crystals on cemented carbide (WC-Co) SPUN inserts. Diamond (Dia.), carbon (GC-glassy spherical form), iridium (Ir), molybdenum (Mo), palladium (Pd), platinum (Pt), tungsten (W), and tantalum (Ta) powders were used as seeding materials for crystal growth. Scanning electron microscopy (SEM) data revealed the development of a few diamond crystals in platinum, iridium, and tungsten powders. The seeding with carbon, tantalum, and diamond powders formed clustered microcrystalline diamond (MCD) crystals, although other powders produced discrete crystals. Tantalum and diamond-seeded powders produced the most significant number and size of crystals. According to micro-Raman spectroscopy (µ-RS), tantalum powder had the lowest I _D/I _G ratio and the most excellent sp ³ bonding. X-ray diffraction (XRD) revealed the maximum diamond intensity in the (111) plane. According to atomic force microscopy (AFM), diamond and molybdenum powders had the largest grains, whereas tantalum powder had the smallest root mean square roughness value with a homogeneous grain distribution. The Vickers microhardness (VHN) test confirmed the highest hardness value for diamond and tantalum seeded powder coatings with the least amount of radial cracking. Field emission scanning electron microscopy (FESEM) revealed that both powders had higher film thickness values.

Novel Dispersion of 1D Nanofiber Fillers for Fast Ion-Conducting Nanocomposite Polymer Blend Quasi-Solid Electrolytes for Dye-Sensitized Solar Cells

Electrospun nanocomposite polymer blend poly(vinylidene difluoride-co-hexafluoropropylene) (PVDF-HFP)/poly(methyl methacrylate) (PMMA) membranes with a novel dispersion of x wt % of one-dimensional (1D) TiO₂ nanofiber fillers (x = 0.0-0.8 in steps of 0.2) were developed using the electrospinning technique. The developed nanocomposite polymer membranes were activated using various redox agents such as LiI, NaI, KI, and tetrabutyl ammonium iodide (TBAI). Introduction of the 1D TiO₂ nanofiber fillers improves the amorphous nature of the blended polymer membrane, as confirmed through X-ray diffraction (XRD) and Fourier transform infrared (FTIR), and yielded an electrolyte uptake of over 480% for a 6 wt % TiO₂ nanofiber filler-dispersed sample. PVDF-HFP/PMMA-1D 6 wt % TiO₂ nanofiber fillers with the LiI-based redox electrolyte provided a high conductivity of 2.80 × 10^-2 S cm^-1 and a power conversion efficiency (PCE) of 8.08% to their fabricated dye-sensitized solar cells (DSSCs). The observed better ionic conductivity and efficiency of the fabricated DSSCs could be due to the faster movement of the smaller-ionic-radius (Li) ions entrapped inside the amorphous polymer. This enhanced mobility of ions in the quasi-solid electrolyte leads to faster regeneration of the depleting electrons in the photoanode, resulting in improved efficiency. Further, the achieved high conductivity was analyzed in terms of the dynamics and relaxation mechanisms involved by the ionic charge carriers with complex impedance spectroscopy using a random barrier model and Havriliak-Negami formulation. It was observed that the high-conducting PVDF-HFP/PMMA-1D 6 wt % TiO₂ nanofiber fillers with LiI-based redox electrolyte show better ac conductivity parameters such as a σ of 5.82 × 10^-2 S cm^-1, ω_e (12685 rad s^-1), τ_e (0.909 × 10^-4 s), and n (0.578). Also, dielectric studies revealed that the high-conducting sample has a higher dielectric constant and subsequently high loss. The J-V characteristics were studied using the equivalent circuit of a single-diode model, and the parameters influencing the photovoltaic performance were determined by Symbiotic Organisms Search (SOS) algorithm. The results suggest that the high-efficient sample possesses a minimum series resistance of 1.33 Ω and a maximum shunt resistance of 997 Ω. Hence, the highest-conducting electrospun-blended polymeric nanocomposite (PVDF-HFP-PMMA-6 wt % TiO₂ nanofiber fillers) with LiI-based redox agent and tert-butyl pyridine (TBP) additive as the polymer quasi-solid electrolyte nanofibrous membrane can be a better electrolyte for high-performance dye-sensitized solar cell applications.

A hybrid tiny YOLO v4-SPP module based improved face mask detection vision system

Law offenders take advantage of face masks to conceal their identities and in the present time of the COVID-19 pandemic wearing face masks is a new norm which makes it a daunting task for the investigation agencies to identify the offenders. To address the issue of detection of people wearing face masks using surveillance cameras, we propose a novel face mask vision system that is based on an improved tiny YOLO v4 object detector. The face masks detection network of the proposed vision system is developed by integrating tiny YOLO v4 with spatial pyramid pooling (SPP) module and additional YOLO detection layer and tested and validated on a self-created face masks detection dataset consisting of more than 50,000 images. The proposed tiny YOLO v4-SPP network achieved a mAP (mean average precision) value of 64.31% on the employed dataset which was 6.6% higher than tiny YOLO v4. Specifically, for detection of the presence of a small object like a face mask on the face region, the proposed tiny YOLO v4-SPP based vision system achieved an AP (average precision) of 84.42% which was 14.05% higher than the original tiny YOLO v4 thus, ensuring that the proposed network is capable of accurate detection of a mask on the face region in real-time surveillance applications where visibility of complete face area is a guideline.

Validation of an HPLC method for estimation of cefotaxime from dried blood spot: alternative to plasma-based PK evaluation in neonates

Aim: Pharmacokinetic evaluation of cefotaxime in neonates is currently a challenge due to the large volume requirement of blood for its analysis by existing methods. A dried blood spot (DBS) based method is the best alternative. Materials & methods: We validated an HPLC method for estimation of cefotaxime from DBS and plasma. Extraction employed a simple procedure using acetonitrile and buffer. Selective separation of cefotaxime was achieved on a C8 column using gradient programming. Results & conclusion: The linearity of the method ranged from 2 to 200 μg/ml with acceptable precision and accuracy for both plasma and DBS. Hematocrit was not affecting the assay accuracy. A strong correlation and interchangeability observed with the plasma method proves its clinical validity for application to PK evaluations.

An Amberlite IRA-400 Cl- ion-exchange resin modified with Prosopis juliflora seeds as an efficient Pb2+ adsorbent: adsorption, kinetics, thermodynamics, and computational modeling studies by density functional theory

A Prosopis juliflora-seed-modified Amberlite IRA-400 Cl- ion-exchange resin (hereafter denoted as SMA resin) is used for the removal of Pb2+ from wastewater. SEM, EDX, FT-IR, BET, XRD, and XPS analyses were used to characterize the SMA resin. Parameters such as Pb2+ concentration, pH, temperature, and time are optimized. The obtained results show that the SMA resin has high efficiency for the removal of Pb2+ (73.45%) at a concentration of 100 mg L-1 and a dosage of 0.01 g at pH 6. Thermodynamic studies indicate that the adsorption was spontaneous with negative ΔH° and ΔS° values at all temperatures; pseudo-second-order kinetics and the Langmuir adsorption isotherm provided the best fit (q max = 106 mg g-1 and R 2 = 0.99) from 298 to 338 K. In addition, a diffusion-controlled mechanism at 298 K was observed from intra-particle studies. A desorption and recovery process has been applied successfully to the SMA adsorbent. The obtained results showed desorption of 90.7% at pH 2.5 with 86.3% recovery over six cycles. Furthermore, the DFT results suggest that all the functional groups of the SMA resin possibly bind with Pb2+ and, of these, the -C[double bond, length as m-dash]O group shows the highest binding energy towards Pb2+. Moreover, the high-efficiency removal of Pb2+ from synthetic wastewater using the proposed SMA resin was demonstrated to show the real-life application potential.

A rapid green synthesis of Ag/AgCl-NC photocatalyst for environmental applications

The present study focuses on extract-mediated Ag nanoparticles (NPs), AgCl-NPs, and Ag/AgCl nanocomposites (NCs) as photocatalysts along with its antimicrobial and dye degradation activities. The synthesis of these NPs and NCs was performed by using Azadirachta indica plant fruit extract and analyzed using UV-Vis spectroscopy to confirm the synthesis and band gap of these NPs and NCs, X-ray diffraction (XRD) to determine its size and crystalline nature. Fourier transform infrared spectroscopy (FTIR) to discern phytochemicals, responsible for the reduction and capping of the synthesized NCs. Scanning electron microscopy analysis (SEM), transmission electron microscopy analysis (TEM), and energy dispersive X-ray (EDX) spectroscopy analysis were performed to validate the morphology and presence of silver and chloride percentage in the composites. Later, these NPs and NCs were used for their potential role in photocatalytic degradation of methylene blue dye and antibacterial activity against Escherichia coli and Staphylococcus aureus of human pathogen. The prepared Ag/AgCl-NCs exhibited an enhanced photocatalytic and antibacterial activities in comparison with pure Ag and AgCl nanomaterials. However, green-synthesized NPs and NCs played dual roles as a photocatalyst and antibacterial agent in various biomedical and industrial sectors. Moreover, we found that it might be a hot research in many other environmental applications in upcoming days.

Effects of COVID-19 lockdown phases in India: an atmospheric perspective

Coronavirus disease 2019 (COVID-19) is an infectious disease caused by severe acute respiratory syndrome coronavirus. It was first identified in December 2019 in Wuhan, Hubei, China, and has resulted in an ongoing pandemic. As of 5 July 2020, more than 11.1 million cases have been reported across 188 countries and territories, resulting in more than 528,000 deaths. More than 6.03 million people have recovered. The entire world population currently faces enormous challenges (i.e., social, environmental, health, and economic) due to the impact of COVID-19. In this regard, the affected countries are now trying to slow down the virus's transmission through social-distancing, lockdowns, increasing the number of tests and treatment facilities. There have been four lockdowns (25 March 2020-31 May 2020), and two unlock periods (1 June-31 July 2020) in India. Aerosol Optical Depth (AOD) has been analyzed using MODIS satellite data during various phases of lockdowns over India. With the implementation of lockdown steps, AOD values dropped significantly over various regions. A significant reduction in AOD over the North-Central regions (up to -50%) compared to the regions in the South or Northeast India. The AOD over these regions was significantly affected by the lock/unlock phases. It was also observed that there was a considerable buildup of AOD during the pre-lockdown period in the year 2020 as compared to the past two years.