7 research outputs found

    New Stationary Methods for Studying the Kinetics of Redox Reactions Occurring at Inert Semiconductor/Redox Electrolyte Electrodes. I. The »L ∩ P« Method

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    In this first paper, a new method has been theoretically grounded, for studying the kinetics of redox reactions occurring simultaneously at multielectrodes of the type inert semiconductor / redox electrolyte, representing Schottky barriers. The method is based on the simultaneously changing of both the intensity of the illumination (L), and the polarization (P), of the multielectrode; for this reason, the method has been called an »intersection method«, and symbolized by »L ∩ P«. A kinetic model has been developed to account for the effects of these dL and dP variations, in open and closed circuit conditions, and on its basis, the equations of the potentiostatic and galvanostatic »L ∩ P« methods have been obtained. Further, an expression of the specific admittance has resulted, and some particular cases are given, including that of an inert metal/redox electrolyte multielectrode

    New Stationary Methods for Studying the Kinetics of Redox Reactions Occurring at Inert Semiconductor/Redox Electrolyte Electrodes. II. The »a ∩ P« Method

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    In this second paper an other »intersection« method is theoretically grounded. The method is symbolized »a ∩ P«, and it is based on the simultaneously changing of both the activity (activities) of one (or more) electrochemical active species (a), and the polarization (P), of the multielectrode: inert semiconductor / redox electrolyte. Equations for the potentiostatic, respective galvanostatic »a ∩ P« methods have been deduced, and some important kinetic and electroanalytic applications, especially those referring to the inert metallredox electrolyte unielectrodes are given. These methods permit not only to determine the kinetic parameters, but also to separate the total current density j(U) into the two partial current densities j+(U), j-(U), irrespective of the electrode potential U. Finally, the expression resulted for the specific admittance is equivalent to that obtained in the first paper by using the theory of the »L ∩ P« method; this demonstrates the correctness of both »L ∩ P«, and »a ∩ P« theories

    New Stationary Methods for Studying the Kinetics of Redox Reactions Occurring at Inert Semiconductor/Redox Electrolyte Electrodes. I. The »L ∩ P« Method

    Get PDF
    In this first paper, a new method has been theoretically grounded, for studying the kinetics of redox reactions occurring simultaneously at multielectrodes of the type inert semiconductor / redox electrolyte, representing Schottky barriers. The method is based on the simultaneously changing of both the intensity of the illumination (L), and the polarization (P), of the multielectrode; for this reason, the method has been called an »intersection method«, and symbolized by »L ∩ P«. A kinetic model has been developed to account for the effects of these dL and dP variations, in open and closed circuit conditions, and on its basis, the equations of the potentiostatic and galvanostatic »L ∩ P« methods have been obtained. Further, an expression of the specific admittance has resulted, and some particular cases are given, including that of an inert metal/redox electrolyte multielectrode

    A chiral electrochemical system based on l-cysteine modified gold nanoparticles for propranolol enantiodiscrimination: Electroanalysis and computational modelling

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    Enantioselective electrochemical sensors seem to hold the promise for a fast and easy alternative for the chiral probing of bioactive molecules. However, the underlying mechanism responsible for the chiral recognition is rarely known, and suitable investigational tools are dearly missed. Therefore, as a proof-ofconcept, our study is focused on investigating the interaction mechanism of the enantiomers of a chiral drug molecule, namely propranolol (PRNL) with the surface of bare and L-cysteine (L-Cys) modified gold nanoparticles employing various electrochemical techniques (differential pulse voltammetry and electrochemical impedance spectroscopy) and computational modeling (molecular dynamics simulations). If the strong surface adsorption of PRNL antipodes on bare gold nanoparticles may not be exploited for enantioselective recognition, upon the functionalization of the nanostructures with L-Cys, the almost two fold increase in the oxidation current is also accompanied by a cathodic shift (~40 mV) of the peak potential for the S( )-enantiomer. This peak potential shift seems to be the consequence of a favored orientation of the surface adsorbed S( )-enantiomer towards electron transfer and/or a weaker interaction with the chiral selector and thus a higher free energy of the transient diastereoisomeric complex, in comparison with its R(þ)-antipode. Computational modeling highlighted the H-bond donor and acceptor atoms of both the chiral selector (L-Cys) and adsorbates (PRNL enantiomers) responsible for the recorded enantioselective electrochemical signal. Correlations between the observed electrochemical signal and enantioselective molecular interactions occurring at the surface of the electrode may lead the way towards a more rational design of future chiral electrochemical sensing platforms

    Carotid Plaque Features and Inflammatory Biomarkers as Predictors of Restenosis and Mortality Following Carotid Endarterectomy

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    Background: Carotid endarterectomy (CEA) is the first-line surgical intervention for cases of severe carotid stenoses. Unfortunately, the restenosis rate is high after CEA. This study aims to demonstrate the predictive role of carotid plaque features and inflammatory biomarkers (monocyte-to-lymphocyte ratio (MLR), neutrophil-to-lymphocyte ratio (NLR), platelet-to-lymphocyte ratio (PLR), systemic inflammatory index (SII), Systemic Inflammation Response Index (SIRI), and Aggregate Index of Systemic Inflammation (AISI)) in carotid restenosis and mortality at 12 months following CEA. Methods: The present study was designed as an observational, analytical, retrospective cohort study and included all patients over 18 years of age with a minimum of 70% carotid stenosis and surgical indications for CEA admitted to the Vascular Surgery Clinic, Emergency County Hospital of Targu Mures, Romania between 2018 and 2021. Results: According to our results, the high pre-operative values of inflammatory biomarkers—MLR (OR: 10.37 and OR: 6.11; p < 0.001), NLR (OR: 34.22 and OR: 37.62; p < 0.001), PLR (OR: 12.02 and OR: 16.06; p < 0.001), SII (OR: 18.11 and OR: 31.70; p < 0.001), SIRI (OR: 16.64 and OR: 9.89; p < 0.001), and AISI (OR: 16.80 and OR: 8.24; p < 0.001)—are strong independent factors predicting the risk of 12-month restenosis and mortality following CEA. Moreover, unstable plaque (OR: 2.83, p < 0.001 and OR: 2.40, p = 0.04) and MI (OR: 3.16, p < 0.001 and OR: 2.83, p = 0.005) were independent predictors of all outcomes. Furthermore, AH (OR: 2.30; p = 0.006), AF (OR: 1.74; p = 0.02), tobacco (OR: 2.25; p < 0.001), obesity (OR: 1.90; p = 0.02), and thrombotic plaques (OR: 2.77; p < 0.001) were all independent predictors of restenosis, but not for mortality in all patients. In contrast, antiplatelet (OR: 0.46; p = 0.004), statin (OR: 0.59; p = 0.04), and ezetimibe (OR:0.45; p = 0.03) therapy were protective factors against restenosis, but not for mortality. Conclusions: Our data revealed that higher preoperative inflammatory biomarker values highly predict 12-month restenosis and mortality following CEA. Furthermore, age above 70, unstable plaque, cardiovascular disease, and dyslipidemia were risk factors for all outcomes. Additionally, AH, AF, smoking, and obesity were all independent predictors of restenosis but not of mortality in all patients. Antiplatelet and statin medication, on the other hand, were protective against restenosis but not against mortality

    The Predictive Role of Systemic Inflammatory Markers in the Development of Acute Kidney Failure and Mortality in Patients with Abdominal Trauma

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    Background: Abdominal trauma is defined as a variety of injuries to the abdominal wall, solid or hollow intra-abdominal organs, and various intra-abdominal vessels. Recently, there has been a significant amount of interest in the establishment of a reliable biomarker that can predict the outcome in patients with an abdominal injury. The purpose of this study is to confirm the predictive role of inflammatory biomarkers and underlying risk factors and the risk of acute kidney insufficiency (AKI) developing and mortality in abdominal trauma patients; Materials and methods: The current study was intended as an observational, analytical, retrospective cohort study and included all patients over 18 years of age with a diagnosis of abdominal trauma confirmed through a CT scan admitted to the County Emergency Clinical Hospital of Targu-Mureș, Romania between January 2017, and December 2021; Results: Non-survivor patients had a greater age (p = 0.02), as well as a higher prevalence of ischemic heart disease (IHD) (p = 0.007), history of myocardial infarction (MI) (p = 0.002), peripheral arterial disease (PAD) (p = 0.01), chronic kidney disease (CKD) (p = 0.01), and all risk factors (p = 0.0004 and p p = 0.003) and hemoperitoneum (p = 0.008). Multivariate analysis showed a high baseline value for all inflammatory biomarkers that are independent predictors of adverse outcomes for all recruited patients. Furthermore, for all hospitalized patients, the history of MI (p = 0.03; p = 0.001; and p = 0.003), PAD (p = 0.01; p = 0.01; and p = 0.002), obesity (for all p p p = 0.01; and p = 0.001), and kidney injury (p = 0.02; p = 0.004; and p = 0.01) were independent predictors of all outcomes. Moreover, IHD (p = 0.008 and p = 0.02), tobacco (p p = 0.02), and hemoperitoneum (p = 0.009 and p = 0.01) were predictors of mortality and composite endpoint, but not for AKI risk, as well as atrial fibrillation [AF] (p = 0.04) as predictors of the composite endpoint Conclusions: Higher monocyte to lymphocyte ratio (MLR), platelets to lymphocyte ratio (PLR), systemic inflammatory index (SII), neutrophil to lymphocyte ratios (NLR), aggregate inflammatory systemic index (AISI), and systemic inflammatory response index (SIRI) levels at admission, according to our data, highly predict AKI risk and death
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