Properties of proton exchange membranes poly-ethylene terephthalate (PET) films developed by gamma radiation induced grafting and sulfonation technique

Proton exchange membranes (PEMs) were developed by radiation induced grafting of styrene onto poly ethylene terephthalate (PET) and linear low density polyethylene (LLDPE) membranes using two steps technique. Subsequent sulfonation on the PET films was conducted by chlorosulfonic acid (ClSO3H). The PET films in 45% styrene solution at 1500 krad dose has found to show the highest grafting (17.4%) in both techniques while the maximum degree of sulfonation was noticed to be 9% with a soaking time 150 minutes. Surface morphology was investigated from scanning electron microgram (SEM). Proton exchange capacity (PEC) was confirmed by pH change in 0.01 M NaCl solution. Optical and electrical characteristics of the PEMs were performed by the measurements of FTIR optical absorption, electrical impedance, and electrical resistance respectively

Study of physical, mechanical and thermal properties of unidirectional jute fiber reinforced PVC film composites

This paper presents the physical, mechanical and thermal properties of unidirectional jute fiber reinforced polyvinyl chloride (PVC) film composites. Composites (wt % of fiber) of jute fiber reinforced PVC matrix were prepared by compression molding at 160⁰ C. Variable weight ratios of these composites namely 100:0, 95:5, 90:10, 85:15 and 80:20 were prepared and then physical, mechanical and thermal properties were studied. The tensile strength of composites increases with the increase of fiber addition and percentage of elongation at break decreases with increase of fiber addition. Thermal analysis of PVC-jute fiber composites show that thermal degradation of PVC film starts ahead of jute fiber and the degradation of composites was occurring in two stages

Interaction of palmitic acid with losartan potassium at the binding sites of bovine serum albumin

The binding of losartan potassium, an angiotensin II receptor antagonist, to bovine serum albumin was studied by equilibrium dialysis method (ED) in presence or absence of palmitic acid. The study was carried out using ranitidine and diazepam as site-1 and site-2 specific probe, respectively. Different analysis of binding of losartan to bovine serum albumin suggested two sets of association constants: high affinity association constant (k1 = 11.2 x 105 M-1) with low capacity (n1 = 2) and low affinity association (k2 = 2. 63 x 105 M-1) constant with high capacity (n2 = 10) at pH 7.4 and 27°C. During concurrent administration of palmitic acid and losartan potassium in presence or absence of ranitidine or diazepam, it was that found that palmitic acid causes the release of losartan potassium from its binding site on BSA resulting reduced binding of losartan potassium to BSA. The increment in free fraction of losartan potassium was from 13.1% to 47.2 % upon the addition of increased concentration of only palmitic acid at a concentration of 0 x 10-5 M to 16 x 10-5 M. In presence of ranitidine or diazepam as site specific probes, palmitic acid further increases the free fraction of losartan potassium were from 22.8% to 53.4% and 35.3 to 65.5%, respectively. This data provided the evidence of interaction of higher concentration of palmitic acid at the binding sites on BSA changing the pharmacokinetics properties of losartan potassium

Tetranuclear Group 7/8 Mixed-Metal and Open Trinuclear Group 7 Metal Carbonyl Clusters Bearing Bridging 2-mercapto-1-methylimidazole Ligands

The reactivity of group 7 metal dinuclear carbonyl complexes [M2(CO)6(μ-SN2C4H5)2] (1, M = Re; 2, M = Mn) toward group 8 metal trinuclear carbonyl clusters were examined. Reactions of 1 and 2 with [Os3(CO)10(NCMe)2] in refluxing benzene furnished the tetranuclear mixed-metal clusters [Os3Re(CO)13(μ3-SN2C4H5)] (3) and [Os3Mn(CO)13(μ3-SN2C4H5)] (4), respectively. Similar treatment of 1 and 2 with Ru3(CO)12 yielded the ruthenium analogs [Ru3Re(CO)13(μ3-SN2C4H5)] (5), and [Ru3Mn(CO)13(μ3-SN2C4H5)] (6), but in the case of 2 a secondary product [Mn3(CO)10(μ-Cl)(μ3-SN2C4H5)2] (7) was also formed. Compounds 3–6 have a butterfly core of four metal atoms with the M (Mn or Re) at a wingtip of the butterfly and containing a noncrystallographic mirror plane of symmetry. This result provides a potential method for the synthesis of a series of new group 7/8 mixed metal complexes containing a bifunctional heterocyclic ligand. Compound 7 is a unique example of a 54-electron trimanganese complex having bridging 2-mercapto-1-methylimidazolate and chloride ligands. Interestingly, the reaction of 1 with Fe3(CO)12 at 70–75 °C furnished the tri- and dirhenium complexes [Re3(CO)10(μ-H)(μ3-SN2C4H5)2] (8) and [Re2(CO)6(N2C4H5)(μ-SN2C4H5)2] (9), respectively instead of the expected formation of the mixed-metal clusters. The former is an interesting example of a 52-electron trirhenium-hydridic complex containing bridging 2-mercapto-1-methylimidazolate ligand, while the latter can be viewed as a 1-methylimidazole adduct of 1. No mixed Fe–Re complexes were produced in this reaction. The molecular structures of the new compounds 3–5 and 7–9 were established by single-crystal X-ray diffraction analyses and the DFT studies of compounds 5, 7 and 8 are reported

Alkyne activation and polyhedral reorganization in benzothiazolate-capped osmium clusters on reaction with diethyl acetylenedicarboxylate (DEAD) and ethyl propiolate

The reactivity of the face-capped benzothiazolate clusters HOs3(CO)9[μ3-C7H3(R)NS] (1a, R = H; 1b, R = 2-CH3) with alkynes has been investigated. 1a reacts with DEAD at 67 °C to furnish the isomeric alkenyl clusters Os3(CO)9(μ-C7H4NS)(μ3-EtO2CCCHCO2Et) (2a and 3a). X-ray crystallographic analyses of 2a and 3a have confirmed the stereoisomeric relationship of these products and the regiospecific polyhedral expansion that follows the formal transfer of the hydride to the coordinated alkyne ligand in HOs3(CO)9(μ-C7H4NS)(2-DEAD). The significant structural differences between the two isomers, as revealed by the solid-state structures, derives from the regiospecific cleavage of one of the three Os-Os bonds in the intermediate alkenyl cluster Os3(CO)9(μ-C7H4NS)(1-EtO2CCCHCO2Et), which follows hydride transfer to the coordinated alkyne ligand in the pi compound HOs3(CO)9(μ-C7H4NS)(2-DEAD). Control experiments confirm the reversibility of the reaction leading to the formation of 2a and 3a. Whereas heating either isomer in refluxing THF or benzene affords a binary mixture containing 2a and 3a, thermolysis in refluxing toluene leads to the activation of the alkenyl ligand and formation of the new cluster Os3(CO)9(μ-C7H4NS)(μ3-EtO2CCCH2) (4). 4 was independently synthesized from 1a and ethyl propiolate at room temperature. The computed mechanisms that account for the formation of 2a and 3a are presented, along with the mechanism for the reaction of 1a with ethyl propiolate to give 4

Clinical presentation of post-COVID pain and its impact on quality of life in long COVID patients: a cross-sectional household survey of SARS-CoV-2 cases in Bangladesh

Background Pain is one of the prevalent Long COVID Symptoms (LCS). Pain interferes with the quality of life (QoL) and induces disease burden. Purpose The study aimed to elicit the clinical presentation of pain and determine the relationships between QoL and pain in LCS. Methods This household cross-sectional study of 12,925 SARS-CoV-2 cases between July and December 2021 was carried out in eight administrative divisions of Bangladesh. Stratifed random sampling from the cases retrieved from the Ministry of Health was employed. Symptom screening was performed through COVID-19 Yorkshire Rehabilitation Scale, and long COVID was diagnosed according to World Health Organization (WHO) criteria. The analyses were conducted using IBM SPSS (Version 20.00). Results The prevalence of pain in long COVID was between 01 and 3.1% in the studied population. The study also found fve categories of pain symptoms as LCS in Bangladesh: muscle pain 3.1% (95% CI; 2.4–3.8), chest pain 2.4% (95% CI; 1.8–3.1), joint pain 2.8% (95% CI; 2.2–2.3), headache 3.1% (95% CI; 2.4–3.8), and abdominal pain 0.3% (95% CI; 0.01–0.5). People with LCS as pain, multiple LCS, and longer duration of LCS had signifcantly lower quality of life across all domains of the WHOQOL-BREF (P<0.001) compared to asymptomatic cases. Conclusion Three out of ten people with long COVID experience painful symptoms, which can signifcantly reduce their quality of life. Comprehensive rehabilitation can improve the symptoms and reduce the burden of the disease

X-ray Structure of \u3cem\u3emer\u3c/em\u3e-[Mo(CO)\u3csub\u3e3\u3c/sub\u3e(PPh\u3csub\u3e3\u3c/sub\u3e)(\u3cem\u3eκ\u3c/em\u3e\u3csup\u3e2\u3c/sup\u3e-dppm)]

Treatment of [Mo(CO)3(NCMe)3] with bis(diphenylphosphino)methane (dppm) and triphenylphosphine (PPh3) at 50 °C afforded mer-[Mo(CO)3(PPh3)(κ2-dppm)] (1) in 55% yield which has been characterized by single crystal X-ray diffraction studies and spectroscopic measurements. Compound 1 crystallizes in the triclinic space group P−1 with a = 10.3449(6), b = 11.1570(6), c = 17.8961(10) Å, β = 80.8400(10)°, Z = 2 and V = 1959.8(2) Å3