3 research outputs found

    Tailoring the electrochemical charge storage properties of carbonaceous support by redox properties of heteropoly acids: where does the synergy come from?

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    The synergistic effects between two Keggin-type heteropoly acids (HPAs) and carbon surface were examined and elucidated. An improved high rate capability (and potential high capacitor electrode for supercapacitors) of the hybrid materials, obtained by anchoring of α-dodecamolybdophosphoric (MoPA), α-dodecatungstophosphoric (WPA), and their mixture to activated carbon (AC), was achieved through the different mechanism of interaction. In order to elaborate this, a detailed analysis of AC-HPA composites has been performed by scanning electron microscopy (SEM), Brunauer–Emmett–Teller (BET) analysis, temperature-programmed desorption (TPD), Fourier-transform infrared spectroscopy (FTIR), micro Raman spectroscopy, and zeta potential measurements. The zeta potential measurements revealed positive charge of carbon surface thus indicating attractive interactions with negatively charged Keggin anion. The surface analysis has shown that WPA spontaneously reduces the carbon surface, while interaction with MoPA leads to its oxidation. As the consequence of the tailoring of the functional groups at carbon surface through HPAs’ action, the distortion of cyclic voltammograms (CVs) decreased in the following order: AC-MoPA, AC-MoPA-WPA, and AC-WPA. A prominent rectangular shape of AC-WPA, even at an extremely high scan rate of 400 mVs−1, was measured, which is rarely demonstrated for carbon-based composites. By applying the theory of electrode potentials, the HPA-AC synergistic effect was explained and discussed in terms of charge storage improvement of HPA-modified carbon

    Post-trauma cardiovascular risk factors and subclinical atherosclerosis in young adults following the war in Bosnia and Herzegovina

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    Background: Risk of cardiovascular disease (CVD) has been associated with stress from serving in a war, but it has not been established whether children who experience war-related stress are at increased CVD risk. Objective: This study aimed to compare CVD risk factors in young adults according to whether they experienced traumatic events as children during the 1990–1995 war in Bosnia and Herzegovina, and whether those exposed to trauma have evidence of subclinical atherosclerosis. Method: We examined 372 first-year medical students who were preschool children during the war (1990–1995) (average age 19.5 ± 1.7 years, 67% female) in 2007–2010. They completed the Semi-Structured Interview for Survivors of War. CVD risk factors and carotid intima–media thickness (CIMT) measurements were obtained and compared in individuals with and without trauma. We also examined whether increased CIMT was independently associated with trauma after adjustment for other risk factors. Results: From multiple logistic regression, only elevated triglycerides (> 1.7 mmol/l) were associated with a 5.2 greater odds of having experienced trauma. The mean CIMT of subjects with trauma was greater than that of non-trauma-exposed subjects (0.53 mm vs 0.50 mm, p = 0.07). Moreover, trauma was independently associated with higher CIMT (difference = 0.036 mm, p = 0.024) after adjustment for CVD risk factors. Conclusions: We show that most CVD risk factors are associated with post-war trauma in young adults, and, if present, such trauma is associated with higher triglycerides and higher levels of CIMT in multivariable analysis

    Mechanism and Clinical Importance of Respiratory Failure Induced by Anticholinesterases

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    Respiratory failure is the predominant cause of death in humans and animals poisoned with anticholinesterases. Organophosphorus and carbamate anticholinesterases inhibit acetylcholinesterase irreversibly and reversibly, respectively. Some of them contain a quaternary atom that makes them lipophobic, limiting their action at the periphery, i.e. outside the central nervous system. They impair respiratory function primarily by inducing a desensitization block of nicotinic receptors in the neuromuscular synapse. Lipophilic anticholinesterases inhibit the acetylcholinesterase both in the brain and in other tissues, including respiratory muscles. Their doses needed for cessation of central respiratory drive are significantly less than doses needed for paralysis of the neuromuscular transmission. Antagonist of muscarinic receptors atropine blocks both the central and peripheral muscarinic receptors and effectively antagonizes the central respiratory depression produced by anticholinesterases. To manage the peripheral nicotinic receptor hyperstimulation phenomena, oximes as acetylcholinesterase reactivators are used. Addition of diazepam is useful for treatment of seizures, since they are cholinergic only in their initial phase and can contribute to the occurrence of central respiratory depression. Possible involvement of central nicotinic receptors as well as the other neurotransmitter systems – glutamatergic, opioidergic – necessitates further research of additional antidotes
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