196 research outputs found

    New Thermal and Microbial Resistant Metal-Containing Epoxy Polymers

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    A series of metal-containing epoxy polymers have been synthesized by the condensation of epichlorohydrin (1-chloro-2,3-epoxy propane) with Schiff base metal complexes in alkaline medium. Schiff base was initially prepared by the reaction of 2,6 dihydroxy 1-napthaldehyde and o-phenylenediamine in 1  :  2 molar ratio and then with metal acetate. All the synthesized compounds were characterized by elemental, spectral, and thermal analysis. The physicochemical properties, viz., epoxy value, hydroxyl content, and chlorine content [mol/100 g] were measured by standard procedures. The antimicrobial activities of these metal-containing epoxy polymers were carried out by using minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) methods against S. aureus, B. subtilis (Gram-positive bacteria), and E. coli, P. aeruginosa (Gram-negative bacteria). It was found that the ECu(II) showed higher antibacterial activity than other metal-chelated epoxy resin while EMn(II) exhibited reduced antibacterial activity against all bacteria

    Metal-Containing Epoxy Polymers

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    A series of metal-containing epoxy polymers have been synthesized by the condensation of epichlorohydrin (1-chloro-2,3-epoxy propane) with Schiff base metal complexes in alkaline medium. Schiff base was initially prepared by the reaction of 2,6 dihydroxy 1-napthaldehyde and o-phenylenediamine in 1 : 2 molar ratio and then with metal acetate. All the synthesized compounds were characterized by elemental, spectral, and thermal analysis. The physicochemical properties, viz., epoxy value, hydroxyl content, and chlorine content [mol/100 g] were measured by standard procedures. The antimicrobial activities of these metal-containing epoxy polymers were carried out by using minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC) methods against S. aureus, B. subtilis (Gram-positive bacteria), and E. coli, P. aeruginosa (Gram-negative bacteria). It was found that the ECu(II) showed higher antibacterial activity than other metal-chelated epoxy resin while EMn(II) exhibited reduced antibacterial activity against all bacteria

    Characteristics and anticancer properties of Sunitinib malate-loaded poly-lactic-co-glycolic acid nanoparticles against human colon cancer HT-29 cells lines

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    Purpose: To develop poly-lactic-co-glycolic acid (PLGA) -based nanoparticles (NPs) for the delivery of sunitinib malate (STM) to colon cancer cells.Methods: Three different formulations (F1 – F3) were developed by nano-precipitation technique using various concentrations of PLGA. The NPs were evaluated for particle size, polydispersity index, zeta potential, drug entrapment, and drug loading, using differential scanning calorimetry (DSC), Fouriertransform infrared spectroscopy (FTIR), x-ray diffraction (XRD), and scanning electron microscopy (SEM). Furthermore, in vitro drug release and anticancer studies were carried out on the formulations.Results: Among the three NPs, optimized NP (F3) of STM was chosen for in vitro anti-cancer study against H-29 human colon cancer cells lines based on its particle size (132.9 nm), PDI (0.115), zeta potential (-38.12 mV), entrapment efficiency (52.42 %), drug loading (5.24 %), and drug release (91.26 % in 48 h). A significant anti-cancer activity of the optimized NPs was observed, relative to free STM.Conclusion: These findings suggest that STM-loaded NPs possess significant anti-cancer activity against human colon cancer HT-29 cells lines.Keywords: Sunitinib malate, Poly-lactic-co-glycolic acid, Nanoparticles, Colon cance

    Coordination Polymer: Synthesis, Spectral Characterization and Thermal Behaviour of Starch-Urea Based Biodegradable Polymer and Its Polymer Metal Complexes

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    A starch-urea-based biodegradable coordination polymer modified by transition metal Mn(II), Co(II), Ni(II), Cu(II), and Zn(II) was prepared by polycondensation of starch and urea. All the synthesized polymeric compounds were characterized by Fourier transform-infrared spectroscopy (FT-IR), (1)H-NMR spectroscopy, (13)C-NMR spectroscopy, UV-visible spectra, magnetic moment measurements, differential scanning calorimeter (DSC), and thermogravimetric analysis (TGA). The results of electronic spectra and magnetic moment measurements indicate that Mn(II), Co(II), and Ni(II) complexes show octahedral geometry, while Cu(II) and Zn(II) complexes show square planar and tetrahedral geometry, respectively. The thermogravimetric analysis revealed that all the polymeric metal complexes are more thermally stable than the parental ligand. In addition, biodegradable studies of all the polymeric compounds were also carried out through ASTM standards of biodegradable polymers by CO(2) evolution method

    Bimetallic metal-organic frameworks for controlled catalytic graphitization of nanoporous carbons

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    Single metal-organic frameworks (MOFs), constructed from the coordination between one-fold metal ions and organic linkers, show limited functionalities when used as precursors for nanoporous carbon materials. Herein, we propose to merge the advantages of zinc and cobalt metals ions into one single MOF crystal (i.e., bimetallic MOFs). The organic linkers that coordinate with cobalt ions tend to yield graphitic carbons after carbonization, unlike those bridging with zinc ions, due to the controlled catalytic graphitization by the cobalt nanoparticles. In this work, we demonstrate a feasible method to achieve nanoporous carbon materials with tailored properties, including specific surface area, pore size distribution, degree of graphitization, and content of heteroatoms. The bimetallic-MOF-derived nanoporous carbon are systematically characterized, highlighting the importance of precisely controlling the properties of the carbon materials. This can be done by finely tuning the components in the bimetallic MOF precursors, and thus designing optimal carbon materials for specific applications

    Model Free Approach for Non-Isothermal Decomposition of Un-Irradiated and γ-Irradiated Silver Acetate: New Route for Synthesis of Ag2O Nanoparticles

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    Kinetic studies for the non-isothermal decomposition of unirradiated and γ-irradiated silver acetate with 103 kGy total γ-ray doses were carried out in air. The results showed that the decomposition proceeds in one major step in the temperature range of (180–270 °C) with the formation of Ag2O as solid residue. The non-isothermal data for un-irradiated and γ-irradiated silver acetate were analyzed using Flynn-Wall-Ozawa (FWO) and nonlinear Vyazovkin (VYZ) iso-conversional methods. These free models on the investigated data showed a systematic dependence of Ea on α indicating a simple decomposition process. No significant changes in the thermal decomposition behavior of silver acetate were recorded as a result of γ-irradiation. Calcinations of γ-irradiated silver acetate (CH3COOAg) at 200 °C for 2 hours only led to the formation of pure Ag2O mono-dispersed nanoparticles. X-ray diffraction, FTIR and SEM techniques were employed for characterization of the synthesized nanoparticles

    Biomedical and photocatalytic applications of biosynthesized silver nanoparticles: Ecotoxicology study of brilliant green dye and its mechanistic degradation pathways

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    © 2020 Elsevier B.V. The preparation of nanoparticles from biological materials is an economic and environmentally friendly strategy with several advantages. The current study is focused to synthesize silver nanoparticles using Petroselinum crispum plant extract. Various characteristics of biologically synthesized AgNPs were determined with UV–Visible (UV/Vis) Spectroscopy, X-ray Diffraction (XRD), Fourier Transform Infrared (FTIR) Spectroscopy, and High-Resolution Transmission Electron Microscopy (HRTEM). The plasmonic resonance peak at 425 nm ensured the formation of AgNPs. The FTIR analysis showed that the as-synthesized particles contain alcoholic and polyphenolic constituents, which are responsible for their capping and reduction. The HRTEM results revealed spherical shape of AgNPs with size ranging from 25 to 90 nm. The as-synthesized particles demonstrated excellent antibacterial properties against Gram positive and Gram-negative bacteria. The antioxidant applications of the particles were determined with 2,2-diphenyle-1-picrylhydrazyl (DPPH). Moreover, the photocatalytic application of the synthesized AgNPs was evaluated for brilliant green dye (BG). The results demonstrated high degradation of BG due to small size and well-dispersed nature of AgNPs. Degradation products of BG were identified to suggest degradation pathways. The eco-toxicity of the BG and constituents derived from the dye were studied with Ecological Structure Activity Relationship (ECOSAR) software

    Overview on Juvenile Primary Fibromyalgia Syndrome

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    JPFS (juvenile primary fibromyalgia syndrome) is a musculoskeletal pain illness that affects children and adolescents. The intricacy of the clinical picture in JPFS has not been adequately characterized in the literature. JFMS symptoms are sometimes difficult to compare to adult fibromyalgia syndrome since many of them are "medically unexplained" and frequently overlap with other medical disorders.  The etiology of the illness is multifaceted, with impaired central pain processing being a significant contributor. Musculoskeletal pain that is severe and pervasive is the defining symptom. Other signs and symptoms include headaches, stiffness, subjective joint swelling, sleep and mood disorders, and headaches. Multiple sensitive spots might be found during a physical examination. The diagnosis has certain criteria and is clinical. Early detection and treatment are crucial. The gold standard of care combines a variety of modalities, but most significantly, exercise and cognitive behavioral therapy. The outlook varies, and symptoms might last well into adulthood. Discussing the epidemiology, etiology, pathophysiology, clinical symptoms, diagnosis, and management of JPFS is the goal of the review

    Codon Usage Is Influenced by Compositional Constraints in Genes Associated With Dementia

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    Dementia is a clinical syndrome characterized by progressive cognitive decline, and the symptoms could be gradual, persistent, and progressive. In the present study, we investigated 47 genes that have been linked to dementia. Compositional, selectional, and mutational forces were seen to be involved. The influence of these two compositional constraints on codon usage bias (CUB) was positive for nucleotide A and negative for GC. Nucleotide A also experienced the highest mutational force, and GC-ending codons were preferred over AT-ending codons. A high bias towards GC-ending codons enhanced the gene expression level, evidenced by the positive association between CAI and GC-ending codons. The unusual behavior of TTG codon showing an inverse relationship with GC-ending codon and negative influence of gene expression, a behavior contrary to all other GC-ending codons, shows operative selectional force. Furthermore, parity analysis, higher translational selection value, preference of GC-ending codons over AT-ending codons, and the association of gene length with gene expression refer to the dominant role of selection pressure with compositional constraint and mutational force shaping codon usage
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