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.

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 Cα(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.

An Open-Label Randomized Controlled Trial Comparing Effectiveness of Aggressive Hydration Versus High-dose Rectal Indomethacin in the Prevention of Postendoscopic Retrograde Cholangiopancreatographic Pancreatitis (AHRI-PEP).

BACKGROUND: Although rectal administration of nonsteroidal anti-inflammatory drugs is recommended as the standard pharmacologic modality to prevent postendoscopic retrograde cholangiopancreatography (ERCP) post-ERCP pancreatitis (PEP), vigorous periprocedural hydration (vHR) with lactated Ringer's solution (LR) is emerging as an effective prophylaxis modality for PEP. There has been no head-to-head comparison between these 2. STUDY: This was a single-center, randomized, open-label, noninferiority, parallel-assigned, equal allocation, controlled clinical trial in a tertiary care hospital. Consecutive adults referred for ERCP, satisfying predefined inclusion criteria, underwent simple randomization and blinded allocation into 2 groups. Those allocated to vHR received intravenous LR at 3 mL/kg/h during procedure, 20 ml/kg bolus immediately afterward, and then at 3 mL/kg/h for another 8 hours. Those randomized to rectal Indomethacin received only per-rectal 100 mg suppository immediately post-ERCP. Assuming PEP of 9% in Indomethacin arm and noninferiority margin of 4%, we calculated sample size of 171 patients in each arm for 80% power and α-error 5%. Primary outcome was incidence of PEP, within 1 week, as defined by Cotton's criteria. All analysis were done by intention-to-treat. RESULTS: Between October, 2017 to February, 2018, 521 patients were assessed. In all, 352 were enrolled, 178 randomized to vHR, and 174 to per-rectal Indomethacin. Baseline details and ERCP outcomes were not different between 2 groups. PEP occurred in 6 (1.7%) overall, with 1 (0.6%) in hydration arm, and 5 (2.9%) in indomethacin arm; an absolute risk reduction of 2.3% (95% confidence interval: 0.9%-3.5%) and odds ratio of 0.19 (95% confidence interval: 0.02-1.65). Three patients developed severe PEP, all receiving indomethacin. CONCLUSIONS: vHR with LR is noninferior to postprocedure per-rectal Indomethacin for PEP prevention (ClinicalTrials.govID:NCT03629600).

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.

Draft Genome Sequence of a Multidrug-Resistant and Novel Sequence Type 6130 Klebsiella quasipneumoniae Strain C11S11_BCSIR Isolated from Wastewater of a Tertiary Care Hospital in Chattogram, Bangladesh.

In this article, we report draft genome sequence and annotation of Klebsiella quasipneumoniae from the wastewater source in Bangladesh. Here, we identified Klebsiella quasipneumoniae strain C11S11_BCSIR, a multidrug-resistant pathogenic bacterium harboring seven antimicrobial resistance genes of five major antibiotic classes with a novel multilocus sequence type (MLST) (ST6130).

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.

A combination of circulating microRNA-375-3p and chemokines CCL11, CXCL12, and G-CSF differentiate Crohn's disease and intestinal tuberculosis.

Differentiation of Crohn's disease (CD) from intestinal tuberculosis (ITB) is a big challenge to gastroenterologists because of their indistinguishable features and insensitive diagnostic tools. A non-invasive biomarker is urgently required to distinguish ITB/CD patients particularly in India, a TB endemic region, where CD frequency is increasing rapidly due to urbanization. Among the three differentially expressed miRNAs obtained from small RNA transcriptomic profiling of ileocaecal/terminal ileal tissue of ITB/CD patients (n = 3), only two down-regulated miRNAs, miR-31-5p, and miR-215-5p showed comparable data in qRT-PCR. Out of which, only miR-215-5p was detectable in the patient's plasma, but there was no significant difference in expression between ITB/CD. On the other hand, miR-375-3p, the pulmonary TB specific marker was found in higher amount in the plasma of ITB patients than CD while reverse expression was observed in the ileocaecal/terminal ileal tissues of the same patients. Next, using Bioplex pro-human cytokine 48-plex screening panel, only three chemokines, Eotaxin-1/CCL11, SDF-1α/CXCL12, and G-CSF have noted significantly different levels in the serum of ITB/CD patients. ROC analysis has revealed that compared to a single molecule, a combination of miR-375-3p + Eotaxin-1/CCL11 + SDF-1α /CXCL12 + G-CSF showed a better AUC of 0.83, 95% CI (0.69-0.96) with 100% specificity and positive predictive value while sensitivity, negative predictive value, and accuracy were 56%, 69%, and 78% respectively in distinguishing ITB from CD. This study suggests that a combination of plasma markers shows better potential in differentiating ITB from CD than a single marker and this panel of markers may be used for clinical management of ITB/CD patients.

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.

Levothyroxine Absorption Test to Differentiate Pseudomalabsorption from True Malabsorption.

BACKGROUND: The levothyroxine absorption test for evaluation of pseudomalabsorption in patients with primary hypothyroid is not standardised. An individual in whom a workup for malabsorption is warranted remains undefined. METHODS: Twenty-five euthyroid, 25 newly diagnosed hypothyroid, 25 treated hypothyroid with normalised TSH, and 25 hypothyroid subjects with elevated TSH despite adequate dose of levothyroxine for more than 6 months, and 10 euthyroid subjects with true malabsorption were administered levothyroxine (10 µg/kg or maximum 600 µg) to study its absorption profile by measuring free T4 level at hourly intervals for 5 h. Results : Free T4 peaked at 3 h with marginal insignificant decline at 4 h in all groups. The increments of free T4 (between baseline and 3 h) of the four groups (except malabsorption) were not statistically different. The mean increment of free T4 in true malabsorption was 0.39 ng/dL (95% CI: 0.29-0.52) and it was 0.78 ng/dL (95% CI: 0.73-0.85) (10.4 pmol/L) for other groups combined together. The cut off of free T4 increment at 3 h from baseline above 0.40 ng/dL had a sensitivity of 97% and specificity of 80% (AUC 0.904, p < 0.001) to exclude true malabsorption. CONCLUSION: Subjects with elevated TSH on adequate dose of LT4 can be reliably diagnosed to be non-adherent to treatment with levothyroxine absorption test. The incremental value above 0.40 ng/dL (5.14 pmol/L) at 3 h may be useful to identify individuals where workup of malabsorption is unwarranted.

Correction: An efficient one pot ipso-nitration: structural transformation of a dipeptide by N-terminus modification.

[This corrects the article DOI: 10.1039/C5RA09789D.].

Visible-Light-Induced Organophotoredox-Catalyzed Phosphonylation of 2 H-Indazoles with Diphenylphosphine Oxide.

A metal-free visible-light-induced phosphonylation of 2 H-indazoles with diphenylphosphine oxide has been developed using rose bengal as an organophotoredox catalyst under ambient air at room temperature. A library of diphenyl(2-phenyl-2 H-indazol-3-yl)phosphine oxide with broad functionalities has been synthesized in high yields. The experimental result suggests the radical pathway of the reaction.