DMSO promoted catalyst-free oxidative C-N/C-O couplings towards synthesis of imidazoles and oxazoles

Dimethyl sulfoxide (DMSO)-promoted catalyst-free oxidative C-N coupling and C-O coupling under oxidant-free conditions are outlined. This protocol is operationally simple and leads to various functionalized substituted imidazoles or oxazoles in good yields. To date, a very limited number of oxidation protocols have been established, where DMSO acts solely as a catalyst or an oxidant or both. In this report, DMSO is not only used as a C-N/C-O coupling agent but is also used as the oxidant required for these oxidative transformations. Hence, our demonstrated DMSO-promoted catalyst-free coupling transformation has the ability to lead to a new dimension in the field of oxidative coupling.

A Rare Case Report of Limb Body Wall Complex

Limb body wall complex (LBWC), also known as body stalk anomaly, is a rare and lethal disorder of the anterior abdominal wall. It is characterized by a severe combination of congenital malformations in the fetus, including, abdomino- and/or thoracoschisis, exencephaly/encephalocele, limb deformities, and facial clefts. Short umbilical cord, abdominal placental attachment, and spinal anomalies are among other manifestations of this disorder. The cause of LBWC is still unknown. The main hypotheses include embryonic dysplasia, early amniotic rupture, and vascular accident during embryonic development. We present a case of LBWC that was detected prenatally on ultrasound (USG) imaging and later confirmed postnatally in a Rh-negative mother at the menstrual age of 14 weeks.

Silica-Derived Nanostructured Electrode Materials for ORR, OER, HER, CO2RR Electrocatalysis, and Energy Storage Applications: A Review

Silica-derived nanostructured catalysts (SDNCs) are a class of materials synthesized using nanocasting and templating techniques, which involve the sacrificial removal of a silica template to generate highly porous nanostructured materials. The surface of these nanostructures is functionalized with a variety of electrocatalytically active metal and non-metal atoms. SDNCs have attracted considerable attention due to their unique physicochemical properties, tunable electronic configuration, and microstructure. These properties make them highly efficient catalysts and promising electrode materials for next generation electrocatalysis, energy conversion, and energy storage technologies. The continued development of SDNCs is likely to lead to new and improved electrocatalysts and electrode materials. This review article provides a comprehensive overview of the recent advances in the development of SDNCs for electrocatalysis and energy storage applications. It analyzes 337,061 research articles published in the Web of Science (WoS) database up to December 2022 using the keywords "silica", "electrocatalysts", "ORR", "OER", "HER", "HOR", "CO2RR", "batteries", and "supercapacitors". The review discusses the application of SDNCs for oxygen reduction reaction (ORR), oxygen evolution reaction (OER), hydrogen evolution reaction (HER), carbon dioxide reduction reaction (CO2RR), supercapacitors, lithium-ion batteries, and thermal energy storage applications. It concludes by discussing the advantages and limitations of SDNCs for energy applications.

Electrochemistry-enabled residue-specific modification of peptides and proteins

Selective chemical reactions at precise amino acid residues of peptides and proteins have become an exploding field of research in the last few decades. With the emerging utility of bioconjugated peptides and proteins as drug leads and therapeutic agents, the design of smart protocols to modulate and conjugate biomolecules has become necessary. During this modification, the most important concern of biochemists is to keep intact the structural integrity of the biomolecules. Hence, a soft and selective biocompatible reaction environment is necessary. Electrochemistry, a mild and elegant tunable reaction platform to synthesize complex molecules while avoiding harsh and toxic chemicals, can provide such a reaction condition. However, this strategy is yet to be fully exploited in the field of selective modification of polypeptides. With this possibility, the use of electrochemistry as a reaction toolbox in peptide and protein chemistry is flourishing day by day. Unfortunately, there is no suitable review article summarizing the residue-specific modification of biomolecules. The present review provides a comprehensive summary of the latest manifested electrochemical approaches for the modulation of five redox-active amino acid residues, namely cysteine, tyrosine, tryptophan, histidine and methionine, found in peptides and proteins. The article also highlights the incredible potential of electrochemistry for the regio- as well as chemoselective bioconjugation strategy of biomolecules.

Self-Supported Ag/Pt/Pd Alloy Aerogels as High-Performance Bifunctional and Durable Electrocatalysts for Methanol and Ethanol Oxidation Reactions

Assembly of nanoparticles (NPs) into functional macrostructures is imperative for the development of NP-based devices. However, existing methods employ insulating organic ligands, polymers, and biomolecules as mediators for the NP assembly, which are detrimental for charge transport and interparticle coupling that impede the efficient integration of low-dimensional properties. Herein, we report a methodology for the direct self-supported assembly of Ag/Pt/Pd alloy NPs into high surface area (119.1 ± 3.9 to 140.1 ± 5.7 m2/g), mesoporous (19.7 ± 6.2 to 23.0 ± 1.6 nm), and conducting nanostructures (aerogels) that show superior electrocatalytic activity and stability in methanol (MOR) and ethanol (EOR) oxidation reactions. Ultrasmall (3.9 ± 1.3 nm) and quasi-spherical Ag/Pt/Pd alloy NPs were synthesized via stepwise galvanic replacement reaction (GRR) of glutathione (GSH)-coated Ag NPs. As-synthesized NPs were transformed into free-standing alloy hydrogels via chemical oxidation of the GSH ligands. The composition of alloy aerogels was tuned by varying the oxidant/thiolate molar ratio of the precursor NP sol that prompts Ag dealloying with in situ generated HNO3, selectively enriching the Pt and Pd catalytic sites on the aerogel surface. The highest-performing alloy aerogel (Ag0.449Pt0.480Pd0.071) demonstrates excellent mass activity for methanol (3179.5 mA/mg) and ethanol (2444.5 mA/mg) electro-oxidation reactions, which are ∼4-5 times higher than those of commercial Pt/C and Pd/C electrocatalysts. The aerogel also maintained high alcohol oxidation activity for 17 h at a constant potential of -0.3 V in an alkaline medium. The synergistic effects of noble metal alloying, high surface area and mesoporosity, and the pristine active surface of aerogels provide efficient interaction of analytes with the nanostructure surface, facilitating both MOR and EOR activity and improving tolerance for poisonous byproducts, enabling the Ag/Pt/Pd alloy aerogel a promising (electro)catalyst for a number of new technologies.

Pd@GO catalyzed stereo- and regio-selective addition of arenes to alkynes and synthesis of coumarins via C-H functionalization

A stereo- and regio-selective addition of arenes to alkynes via C-H bond functionalization has been developed using palladium nanoparticles supported on graphite oxide (Pd@GO) as the reusable catalyst. The prepared catalyst was characterized by various spectroscopic techniques such as FT-IR, TEM, SEM, EDX, P-XRD, and XPS analysis. The thermal stability of the catalyst was established by TGA. The C-H functionalized products were obtained in good to excellent yields (69-92%) at room temperature. The methodology further extended to the synthesis of biologically and pharmaceutically important coumarin molecules from phenols and alkynes. Good to excellent yields of the coumarins (74-92%) were obtained. After the reaction, the catalyst was separated by centrifugation followed by filtration. The recovered catalyst was washed and reused up to five cycles. The advantages of this method are the simple procedure of the catalyst preparation, high catalytic efficiency, high selectivity, good functional group tolerance, low catalyst loading, and gram-scale synthesis.

A sustainable avenue for the synthesis of propargylamines and benzofurans using a Cu-functionalized MIL-101(Cr) as a reusable heterogeneous catalyst

A heterogeneous copper-catalyzed A3 coupling reaction of aldehydes, amines, and alkynes for the synthesis of propargylamines and benzofurans has been developed. Here, the modified metal-organic framework MIL-101(Cr)-SB-Cu complex was chosen as the heterogeneous copper catalyst and prepared via post-synthetic modification of amino-functionalized MIL-101(Cr). The structure, morphology, thermal stability, and copper content of the catalyst were determined by FT-IR, PXRD, SEM, TEM, EDX, TGA, XPS, and ICP-OES. The catalyst shows high catalytic activity for the aforementioned reactions under solvent-free reaction conditions. High yields, low catalyst loading, easy catalyst recovery and reusability with not much shrink in catalytic activity, and a good yield of 82% in gram-scale synthesis are some of the benefits of this protocol that drove it towards sustainability.

Aqueous mediated iodine catalyzed C-N coupling followed by C-C coupling towards 5H-pyrazino[2,3-b]indoles

Our study describes a new development featuring iodine-catalyzed two consecutive oxidative cross-coupling reactions involving C_α(sp³)-H of benzyl amines followed by intramolecular cyclization in water under air. Here, C-N coupling followed by C-C coupling occurs in a green environment to provide a variety of 5H-pyrazino[2,3-b]indoles within a short time period.

Bioactive properties and organosulfur compounds profiling of newly developed garlic varieties of Bangladesh

Studies are being carried out on achieving the maximum quality of garlic through various approaches. In Bangladesh, new garlic varieties (BARI 1-4, BAU-1, BAU-2, BAU-5) have been recently developed by artificial selection to enhance their quality. The present study aimed to evaluate their potency in terms of bioactive properties and organosulfur compounds content using different bioassay and GC-MS techniques while comparing them with other accessible varieties (Chinese, Indian, Local). The new variety, BARI-3 showed the highest antioxidant activity and total phenolic content. It was also found with the highest level of a potent blood pressure-lowering agent, 2-vinyl-4H-1,3-dithiine (78.15 %), which is never reported in any garlic at this percentage. However, the local variety exhibited greater inhibitory properties against the tested organisms including multidrug-resistant pathogens compared to other varieties. This study primarily shows the potential of these two kinds of garlic for their further utilization and development.

Cu incorporated polymeric heterogeneous catalyst: Exploring an expedient approach to construct amide bonds and extending its application to triazole hybrid amides synthesis

A self-assembly of copper-grafted imidazole polymeric complex is synthesized via a coordinative-convolution method. The structural characterization of the polymeric copper catalyst was completed through FT-IR, SEM, TEM-EDX, SAED, PXRD, TGA,...

Versatile and Sustainable Approach to Access Biologically Relevant Chromeno[2,3-b]pyridine and Benzylpyrazolyl Coumarin Derivatives Using Graphitic Carbon Nitride as a Reusable Heterogeneous Catalyst

Herein, the synthesis of graphitic carbon nitride (g-C₃N₄) via the simple heating of cheap and readily available urea as the starting material has been reported. The catalytic activity of the prepared g-C₃N₄ was investigated for the synthesis of chromeno[2,3-b]pyridine and benzylpyrazolyl coumarin derivatives in an ethanol medium. The reactions were performed under mild conditions to achieve widely functionalized target products in a one-pot operation. The as-synthesized g-C₃N₄, being a heterogeneous catalyst, demonstrates excellent recyclability up to the 5th consecutive run without a significant decrease in its catalytic activity and yield of the product. A gram-scale reaction was performed to demonstrate the industrial applications of the present protocol. The green chemistry metrics such as environmental factor (E-factor), atom economy (AE), carbon efficiency (CE), and reaction mass efficiency (RME) were calculated and found to be very close to the ideal values. Additionally, operation simplicity, wide substrate scope, easy reusability of the catalyst, and avoidance of metal contamination in the products drive the process toward green and sustainable development.

Static and Resonant Properties and Magnetic Phase Diagram of LiMn2TeO6

Physical properties of the mixed-valent tellurate of lithium and manganese, LiMn2TeO6, were investigated in measurements of ac and dc magnetic susceptibility χ, magnetization M, specific heat Cp, electron spin resonance (ESR), and nuclear magnetic resonance (NMR) in the temperature range 2−300 K under magnetic field up to 9 T. The title compound orders magnetically in two steps at T1 = 20 K and T2 = 13 K. The intermediate phase at T2 < T < T1 is fully suppressed by magnetic field µ0H of about 4 T. Besides magnetic phases transitions firmly established in static measurements, relaxation-type phenomena were observed well above magnetic ordering temperature in resonant measurements.

Streptomyces: The biofactory of secondary metabolites

Natural products derived from microorganisms serve as a vital resource of valuable pharmaceuticals and therapeutic agents. Streptomyces is the most ubiquitous bacterial genus in the environments with prolific capability to produce diverse and valuable natural products with significant biological activities in medicine, environments, food industries, and agronomy sectors. However, many natural products remain unexplored among Streptomyces. It is exigent to develop novel antibiotics, agrochemicals, anticancer medicines, etc., due to the fast growth in resistance to antibiotics, cancer chemotherapeutics, and pesticides. This review article focused the natural products secreted by Streptomyces and their function and importance in curing diseases and agriculture. Moreover, it discussed genomic-driven drug discovery strategies and also gave a future perspective for drug development from the Streptomyces.

Rapid detection of Actinobacillus pleuropneumoniae targeting the apxIVA gene for diagnosis of contagious porcine pleuropneumonia in pigs by Polymerase Spiral Reaction

Actinobacillus pleuropneumoniae is the primary etiological agent of contagious porcine pleuropneumonia associated with serious economic impact on pig husbandry worldwide. Diagnosis of the disease by existing techniques including isolation and identification bacteria followed by serotyping, serological techniques, conventional PCR, real-time PCR and LAMP assays are cumbersome, time consuming, costly and not suitable for rapid field application. A novel isothermal polymerase chain reaction (PSR) technique is standardized for all the reagents, incubation time and incubation temperature against A. pleuropneumoniae. Sensitivity of the assay was determined against various dilutions of purified DNA and total bacterial count. Specificity of the assay was determined against 11 closely related bacterial isolates. The relative sensitivity and specificity was compared with bacterial isolation, conventional PCR and real-time PCR assays. The PSR assay for specific detection was standardized at 64^o C for 30 minutes incubation in a water bath. The result was visible by the naked eye after centrifugation of the reaction mixture or after incorporation of SYBR Green dye as yellow-green fluorescence. The technique was found to be 100% specific and equally sensitive with real-time PCR and 10 times more sensitive than conventional PCR. The PSR assay could be applicable in detection of the organisms in porcine nasal swabs spiked with A. pleuropneumoniae. This is the first ever report on development of PSR for specific detection of A. pleuropneumoniae and can be applied for early diagnosis at field level.

Brine residues and organics in the Urvara basin on Ceres

Ceres is a partially differentiated dwarf planet, as confirmed by NASA's Dawn mission. The Urvara basin (diameter ~170 km) is its third-largest impact feature, enabling insights into the cerean crust. Urvara's geology and mineralogy suggest a potential brine layer at the crust-mantle transition. Here we report new findings that help in understanding the structure and composition of the cerean crust. These results were derived by using the highest-resolution Framing Camera images acquired by Dawn at Ceres. Unexpectedly, we found meter-scale concentrated exposures of bright material (salts) along the crater's upper central ridge, which originate from an enormous depth, possibly from a deep-seated brine or salt reservoir. An extended resurfacing modified the southern floor ~100 Myr after crater formation (~250 Myr), long after the dissipation of the impact-generated heat. In this resurfaced area, one floor scarp shows a granular flow pattern of bright material, showing spectra consistent with the presence of organic material, the first such finding on Ceres beyond the vast Ernutet area. Our results strengthen the hypothesis that Ceres is and has been a geologically active world even in recent epochs, with salts and organic-rich material playing a major role in its evolution.

Palladium incorporated MIL-101(Cr): A heterogeneous and reusable catalyst for C-H functionalization of unactivated arenes

Herein, palladium containing metal-organic framework was designed for utilizing in C-H functionalization of unactivated arenes. The catalyst was prepared via post-synthetic modification of amino-functionalized MIL-101(Cr) and was well characterized using...

Role of cytokines in Granulomatous Colitis

Background: Intestinal tuberculosis (ITB) have significant immunological similarity with Crohn’s disease (CD). T helper cells and various cytokines secreted by them play a very crucial role in the pathogenesis of both the diseases. It is of great clinical relevance in a country like India to perform a comparative study between CD and ITB with respect to pathogenesis. Objectives: To study the levels of four cytokines(IL-4,IL-17, IFN-ϒ & TGF-β1 ) s in serum of patients with CD & ITB which indirectly reflects the levels of CD4+ T cells. Material and method: An observational, cross-sectional study was done on patients, attending Gastroenterolory clinic in a tertiary care hospital, with features of ileitis, colitis or ileo-colitis due to CD or ITB.12 cases of Crohn’s disease & 13 cases of intestinal tuberculosis were taken( control-20 cases). 5 biopsies were taken from the ulcerated mucosa & 3 biopsies were taken from normal mucosa. H & E study & serum levels of four cytokines(IL-4,IL-17, IFN-ϒ & TGF-β1 ) were estimated. Results & analysis: In CD & ITB we found marginal increase of IFN-ϒ & TGF-β1 compared to control. IL17 level was found decreased in ITB compared to control (p=0.001).CD4+ T cells study by ELISA also showed significant increase in the concentration of IFN-γ (p=0.007) in ITB. There was no change in IL4 levels. Conclusion: Cytokines have an important role in the pathogenesis of grannulomatuos inflammatory bowel diseases. The identification of cytokines & their role in the pathogenesis might be helpful for future therapy based on cytokines, and anti-cytokine antibodies. Bangladesh Journal of Medical Science Vol.20(4) 2021 p.784-789

Nanoemulgel for Improved Topical Delivery of Desonide: Formulation Design and Characterization

This research aimed to develop a novel drug delivery system to improve treatment of skin disorders. The system is comprised of a Carbopol 980-based nanoemulgel (NE-gel) containing a desonide (DES; 0.05%, w/w) nanoemulsion (NE), which has a small particle size, high encapsulation efficiency, good thermodynamic stability, good permeation ability, and high skin retention. DES-loaded NE (DES-NE) was prepared by high-pressure homogenization. The developed formulation was characterized by differential scanning calorimetry (DSC), X-ray diffraction, drug release, skin permeation, and drug retention. DES in vitro release and skin permeation studies with different formulations of artificial membrane and rat abdominal skin were performed with the Franz diffusion cell system. Confocal laser scanning microscopy (CLSM) was used to detect the localization and permeation pathways of drugs in the skin. Compared with commercially available gel (CA-gel) and NE, the NE-gel release process conformed to the Higuchi release model (R² = 0.9813). NE-gel prolonged the drug release time and allowed for reduced administration dose and frequency. The unit cumulative permeation of NE and NE-gel through the skin for 12 h was 63.13 ± 2.78 and 42.53 ± 2.06 μg/cm², respectively, values significantly higher (p < 0.01) than that of the CA-gel (30.65 ± 1.25 μg/cm²) and CA-cream (15.21 ± 0.97 μg/cm²). The DES-NE and DES NE-gel skin drug retention was significantly higher than commercially available formulations (p < 0.01). Hence, the prepared NE-gel is a potential vehicle for improved topical DES delivery for better treatment of skin disorders.

Monitoring and evaluating the spatiotemporal variations of the water quality of a stretch of the Bhagirathi-Hugli River, West Bengal, India, using geospatial technology and integrated statistical methods

Water quality is a critical environmental issue because all forms of life depend on the water. The present study primarily focused on the spatiotemporal trends of water quality in a section of the Bhagirathi-Hugli River, West Bengal, using geospatial technology and integrated statistical methods. For this purpose, 83 samples of 7 water parameters were analysed and compared them with Indian Standards (IS 2004), Environmental Protection Agency (EPA 2001) and World Health Organization (WHO 1993) for the protection of aquatic life and human consumption. Correlation, box and whisker plots, paired sample t test, water quality index (WQI), cluster analysis (CA) and principal component analysis (PCA) were applied as an integrated multivariate statistical approach to understanding the nature of water quality. Pollution sources were identified by PCA indicating different origins both naturally and anthropogenic sources. The box and whisker plots displayed the significantly spatiotemporal variations and concentration of the variables. The paired sample t test identified that the surface water quality varied significantly between the seasons with significant value p < 0.05. Cluster analysis grouped 83 monitoring sites into 4 clusters to identify the pollution status such as low, moderate, high and very high pollution sites. Principal component analysis confirmed that the first three PCs with eigenvalues are higher than 1 contributing 90.83% of total variability for various parameters. The conductivity, total dissolved solids (TDS), salt and pH were expressively influenced by the anthropogenic effect while the temperature, oxidation-reduction potential (ORP) and dissolved oxygen (DO) were affected by seasonal factors. Results of WQI ranged from 45.04 to 83.79, and an average value was 69.55 with 69% samples representing poor water quality for drinking and domestic purposes. It also indicates that the water quality of rural sites was better than industrial and urban sites in both seasons and also shows that it was better for the duration of the post-monsoon than pre-monsoon.