Condensation of 4-chloro-2H-chromene-3-carbaldehydes and ethyl-3-aminocrotonates with p-TsOH: a facile approach for the synthesis of chromenyldihydropyridines

The investigated reaction of 4-chloro-2H-chromene-3-carbaldehyde 1a with ethyl 3-oxobutanoate 2a in the presence of ammonium acetate provided two compounds, 2H-chromenyldihydropyridine dicarboxylate 3a and chromenopyridine carboxylate 4a. However, the reaction of 1a with ethyl-3-aminocrotonate 5a in the presence of p-TsOH provided selectively 2H-chromenyldihydropyridine dicarboxylate 3a with very good yield. The established method was applied for the preparation of series of 2H-chromenyldihydropyridine dicarboxylates 3a–q.     

Boundary value problems for multi-term fractional differential equations

Multi-term fractional diffusion-wave equation along with the homogeneous/non-homogeneous boundary conditions has been solved using the method of separation of variables. It is observed that, unlike in the one term case, solution of multi-term fractional diffusion-wave equation is not necessarily non-negative, and hence does not represent anomalous diffusion of any kind.     

Hierarchical neural networks for the storage of correlated memories

A class of hierarchical neural network models introduced by Dotsenko for the storage and associative recall of strongly correlated memories is studied analytically and numerically. In these models, patterns stored in higher levels of the hierarchy represent generalized categories and those stored in lower levels describe finer details. We first show that the models originally proposed by Dotsenko have a serious flaw: they are not able to detect or correct errors in categorization which may be present in the input. We then describe three different models which attempt to overcome this shortcoming of the original models. In the first model, the interaction between different levels of the hierarchy has the form of an external field conjugate to memories stored in the lower level. In the second model, a three-spin interaction term is included in addition to the usual binary interactions of the Hopfield type. The third model makes use of a time delay mechanism to induce, if necessary, transitions between memory states and their complements. Detailed analytical and numerical studies of the performance of these models are presented. Our analysis shows that all three models are able to detect and also to correct in varying degrees any error in categorization that may be present in the input pattern.     

Synthesis,Characterization, and Antimicrobial Studies of New Rigid Linker‐Based Bispyrazolines

The bispyrazolines 4a , 4b , 4c , 4d , 4e were synthesized from the cyclization reaction of bischalcones 3a , 3b , 3c , 3d , 3e with phenyl hydrazine by refluxing under alcoholic medium in the presence of glacial acetic acid. The bischalcones were obtained from the Claisen–Schmidt reaction of acetophenone with dibenzaldehydes 1a , 1b , 1c , 1d , 1e and later were obtained in good yield from the O‐alkylation of 4‐hydroxybenzaldehyde with suitable alkylating agents. The structures of the prepared compounds were determined from the rigorous analysis of their spectral data (UV–vis, IR, ¹H‐NMR, ¹³C‐NMR, and ESI‐MS). The elemental analysis also confirmed the purity of these compounds. All the bischalcones 3a , 3b , 3c , 3d , 3e and bispyrazolines 4a , 4b , 4c , 4d , 4e were screened for their antimicrobial activity using the serial dilution method. Seven bacterial and five fungal species were used as the antimicrobial test strains, namely Klebsiella pneumoniae (MTCC 3384), Pseudomonas aeruginosa (MTCC 424), Escherichia coli (MTCC 443), Staphylococcus aureus (MTCC 443), Bacillus subtilis (MTCC 441), Pseudomonas fluorescens (MTCC 103), and Staphylococcus pyrogens (MTCC 442), and Aspergillus janus (MTCC 2751), Penicillium glabrum (MTCC 4951), Fusarium oxysporum (MTCC 2480), Aspergillus sclerotiorum (MTCC 1008), and Aspergillus niger (MTCC 281), respectively. The minimum inhibitory concentrations (MIC in µg/mL) were determined by using different dilutions.     

Phase transitions and relaxation characteristics of Quantum Magnets and Quantum Glasses

An overview is presented of the phase changes as well as certain relaxation characteristics of model quantum magnets, magnetic glasses and proton glasses. Although the systems considered are quite varied, they are connected by the common themes of tunneling, transverse Ising model, long-ranged interactions and above all, the occurrence of quantum phase transitions. Because the interactions are long-ranged, mean-field theory is eminently suitable for analyzing both the equilibrium and nonequilibrium properties. Wherever pertinent, detailed comparisons with experimental data have been presented.     

Conformational Transitions of the Catalytic Domain of Heme-Regulated Eukaryotic Initiation Factor 2α Kinase, a Key Translational Regulatory Molecule

In mammalian cells, the heme-regulated inhibitor (HRI) plays a critical role in the regulation of protein synthesis at the initiation step through phosphorylation of α-subunit of the eukaryotic initiation factor 2 (eIF2). In this study we have cloned and performed biophysical characterization of the kinase catalytic domain (KD) of rabbit HRI. The KD described here comprises kinase 1, the kinase insertion domain (KI) and kinase 2. We report here the existence of an active and stable monomer of HRI (KD). The HRI (KD) containing three tryptophan residues was examined for its conformational transitions occurring under various denaturing conditions using steady-state and time-resolved tryptophan fluorescence, circular dichroism (CD) and hydrophobic dye binding. The parameter A and phase diagram analysis revealed multi-state unfolding and existence of three stable intermediates during guanidine hydrochloride (Gdn-HCl) induced unfolding of HRI (KD). The protein treated with 6 M Gdn-HCl showed collisional and static mechanism of acrylamide quenching and the constants (K _sv  = 3.08 M⁻¹and K _s   = 5.62 M⁻¹) were resolved using time resolved fluorescence titration. Based on pH, guanidine hydrochloride and temperature mediated transitions, HRI (KD) appears to exemplify a rigid molten globule-like intermediate with compact secondary structure, altered tertiary structure and exposed hydrophobic patches at pH 3.0. The results indicate the inherent structural stability of HRI (KD), a member of the class of stress response proteins.     

Uncapped silver nanoparticles synthesized by DC arc thermal plasma technique for conductor paste formulation

Uncapped silver nanoparticles were synthesized by DC arc thermal plasma technique. The synthesized nanoparticles were structurally cubic and showed wide particle size variation (between 20–150 nm). Thick film paste formulated from such uncapped silver nanoparticles was screen-printed on alumina substrates and the resultant ‘green’ films were fired at different firing temperatures. The films fired at 600 °C revealed better microstructure properties and also yielded the lowest value of sheet resistance in comparison to those corresponding to conventional peak firing temperature of 850 °C. Our findings directly support the role of silver nanoparticles in substantially depressing the operative peak firing temperature involved in traditional conductor thick films technology.     

The Role of Microbiome in Brain Development and Neurodegenerative Diseases

Hundreds of billions of commensal microorganisms live in and on our bodies, most of which colonize the gut shortly after birth and stay there for the rest of our lives. In animal models, bidirectional communications between the central nervous system and gut microbiota (Gut–Brain Axis) have been extensively studied, and it is clear that changes in microbiota composition play a vital role in the pathogenesis of various neurodevelopmental and neurodegenerative disorders, such as Autism Spectrum Disorder, Alzheimer’s disease, Parkinson’s disease, Multiple Sclerosis, Amyotrophic Lateral Sclerosis, anxiety, stress, and so on. The makeup of the microbiome is impacted by a variety of factors, such as genetics, health status, method of delivery, environment, nutrition, and exercise, and the present understanding of the role of gut microbiota and its metabolites in the preservation of brain functioning and the development of the aforementioned neurological illnesses is summarized in this review article. Furthermore, we discuss current breakthroughs in the use of probiotics, prebiotics, and synbiotics to address neurological illnesses. Moreover, we also discussed the role of boron-based diet in memory, boron and microbiome relation, boron as anti-inflammatory agents, and boron in neurodegenerative diseases. In addition, in the coming years, boron reagents will play a significant role to improve dysbiosis and will open new areas for researchers.     

An iterative method for solving nonlinear functional equations

An iterative method for solving nonlinear functional equations, viz. nonlinear Volterra integral equations, algebraic equations and systems of ordinary differential equation, nonlinear algebraic equations and fractional differential equations has been discussed.     

In vitro and ex vivo antitubercular activity of diarylheptanoids from the rhizomes of Alpinia officinarum Hance

Phytochemical investigation of methanol extract of the rhizomes of Alpinia officinarum Hance afforded four known diarylheptanoids 1,7-diphenylhept-4-en-3-one (1), 5-hydroxy-1,7-diphenyl-3-heptanone (2), 5-hydroxy-7-(4″-hydroxy-3″-methoxyphenyl)-1-phenyl-3-heptanone (3), and 7-(4″-hydroxy-3″-methoxyphenyl)-1-phenyl heptan-3-one (4).The acetate derivative of (4), 7-(4″-actetate-3″-methoxy phenyl)-1-phenyl heptan-3-one (5), was prepared. These diarylheptanoids exhibited promising in vitro and ex vivo antitubercular activity for the first time against dormant Mycobacterium tuberculosis H37Ra with the IC₅₀ values between 0.34–47.69 and 0.13–22.91 μM, respectively. All compounds showed comparable activity against Mycobacterium bovis BCG (dormant phage) and did not show any activity against two gram + ve and two gram –ve bacterial strains. These compounds were also weakly cytotoxic up to 300 μM against three human cancer cell lines THP-1, Panc-1 and A549.