Towards hybrid one-pot/one-electrode Pd-NPs-based nanoreactors for modular biocatalysis

Here, fundamental aspects affecting template-assisted engineering of oxidase-associated peroxide oxidation co-catalysis of the modeled microanalytical system based on the hybrid palladium nanoparticles (Pd-NPs) with tailored functional properties were studied. By an accurate tuning and validation of the experimental setup, a modular Pd-NPs-doped one-pot/one-electrode amperometric nanobiosensor for advanced multiplex analyte detection was constructed. The specific operational conditions (electrochemical read-out mode, pH, regeneration procedure) of the modular one-pot/one-electrode nanobiosensor allowed a reliable sensing of L-lactate (with linear dynamic range, LDR = 500 µM – 2 mM, R2 = 0.977), D-glucose (with LDR = 200 µM – 50 mM, R2 = 0.987), hydrogen peroxide (with LDR = 20 µM – 100 mM, R2 = 0.998) and glutaraldehyde (with LDR = 1 – 100 mM, R2 = 0.971). In addition, mechanistic aspects influencing the performance of Pd-NPs-doped one-pot/one-electrode for multiplex analyte sensing were studied in detail. The designed one-pot/one-electrode amperometric nanobiosensor showed a thin layer electrochemical behavior that greatly enhanced electron transfer between the functional hybrid layer and the electrode. Finally, a specific regeneration procedure of the hybrid one-pot/one-electrode and algorithm towards its usage for modular biocatalysis were developed. The reported strategy can readily be considered as a guideline towards the fabrication of commercialized nanobiosensors with tailored properties for advanced modular biocatalysis

Towards hybrid one-pot/one-electrode Pd-NPs-based nanoreactors for modular biocatalysis

Here, fundamental aspects affecting template-assisted engineering of oxidase-associated peroxide oxidation co catalysis of the modeled microanalytical system based on the hybrid palladium nanoparticles (Pd-NPs) with tailored functional properties were studied. By an accurate tuning and validation of the experimental setup, a modular Pd-NPs-doped one-pot/one-electrode amperometric nanobiosensor for advanced multiplex analyte detection was constructed. The specific operational conditions (electrochemical read-out mode, pH, regeneration procedure) of the modular one-pot/one-electrode nanobiosensor allowed a reliable sensing of L-lactate (with linear dynamic range, LDR = 500 µM – 2 mM, R2 = 0.977), D-glucose (with LDR = 200 µM – 50 mM, R2 = 0.987), hydrogen peroxide (with LDR = 20 µM – 100 mM, R2 = 0.998) and glutaraldehyde (with LDR = 1 – 100 mM, R2 = 0.971). In addition, mechanistic aspects influencing the performance of Pd-NPs-doped one-pot/ one-electrode for multiplex analyte sensing were studied in detail. The designed one-pot/one-electrode amper ometric nanobiosensor showed a thin layer electrochemical behavior that greatly enhanced electron transfer between the functional hybrid layer and the electrode. Finally, a specific regeneration procedure of the hybrid one-pot/one-electrode and algorithm towards its usage for modular biocatalysis were developed. The reported strategy can readily be considered as a guideline towards the fabrication of commercialized nanobiosensors with tailored properties for advanced modular biocatalysis

A tandem of GC-MS and electroanalysis for a rapid chemical profiling of bacterial extracellular matrix

Herein an assay toward a rapid and reliable profiling of extracellular matrix of Escherichia coli (E. coli) utilizing a tandem of GC-MS as a tool for definition of the exact chemical nature of low molecular weight compounds and cyclic voltammetry for their high throughput detection is presented. Briefly, during a set of investigations the formation of glycerol in the extracellular matrix (ECM) of E. coli at physiological relevant conditions of cells was revealed. Based on the obtained knowledge, the electrochemical protocol allowing both qualitative and quantitative analyses of glycerol in E. coli ECMs at palladium ink-modified screen printed electrodes with precision values (RSD) <10 % and recovery rates ranged from 98 % to 102 % was proposed. The provided protocol for a rapid electrochemical profiling of the bacterial ECMs can readily be used as a guideline for the controlled electroanalysis of target electroactive signaling analytes in complex biological samples

Electrochemical operational principles and analytical performance of Pd-based amperometric nanobiosensors

Palladium nanoparticles (Pd-NPs) have been approved as an effective catalyst for hydrogen peroxide decomposition which is released during specific enzymatic reactions. However, the general operational principles and electrochemical performance of Pd-NPs-based nanobiosensors have been poorly exploited. Here, the electrochemical behavior of oxidase-associated peroxide oxidation co-catalysis of the modelled microanalytical system based on screen-printed electrodes modified by electroplated PdNPs as an electrocatalyst, glucose oxidase (GOx) or alcohol oxidase (AOx) as a bioreceptor and the ionomer Nafion as a polymeric binding agent was studied in detail. The impact of palladium surface oxides and adsorbed oxygen on the activity and product selectivity in an oxidase type of nanobiosensor was ascertained. To avoid PdO and oxygen electroreduction affecting the entire amperometric response of Pd-NPs-based nanobiosensors, a special two-step polarization procedure was proposed. Under the established electrochemical conditions, Pd-NPs-based nanobiosensors with encapsulated oxidases showed a wide dynamic range towards selective bioanalyte detection, excellent basic line stability, accuracy and resistance to the presence of interfering electrochemical species. This work can serve as a guideline for the search and validation of operational principles of novel biosensors based on nanoparticles

Efficiency of local therapy with the use of a new preparation for oral care at periodontitis in the course of hyperpeptic gastritis after tobacco smoke intoxication

Periodontal diseases, arising against a background of stomach pathology at tobacco addiction remain an acute problem of modern dentistry. The aim of the work is an experimental study of efficiency of application of the new preparation for oral care during treatment of periodontitis simulated against a background of hyperpeptic gastritis under conditions of intoxication by tobacco smoke. At the first stage all experimental animals were divided into 4 groups: І - intact, II - with simulated periodontitis, III - with simulated periodontitis against a background of simulated hyperpeptic gastritis, IV - with simulated periodontitis against a background of hyperpeptic gastritis under conditions of tobacco smoking. Biochemical researches at periodontitis in rats were conducted for determination of influencing stomach pathology and tobacco smoke. On the II stage efficiency of local therapy was studied with the use of the new preparation for oral care and a comparator agent.Results: At experimental periodontitis against a background of hyperpeptic gastritis under conditions of smoking the considerable changes in periodontal tissues typical for the inflammatory process develop. The local therapy at rats with the use of the new preparation resulted in accelerating removing harmful influence of damaging factors and restoring the state of periodontal tissues, than in case of application of the comparator agent. The efficiency of the new preparation consists in normalizing influence on processes of lipid peroxidation, inflammation and activation of the protective systems of oral cavity during periodontitis which arises up against a background of hyperpeptic gastritis

Kinetic features of mediator bioelectrocatalytic oxidation of glucose by "crude" bacterial extracts

«Сырой» белковый экстракт микробных клеток изучали как биоэлектрокатализатор в реакции окисления глюкозы. Такой экстракт, полученный из культуры Escherichia coli BB, рассматривался в данной работе как модельная система, содержащая все ферменты жизненного цикла бактерий

Late Antiquity: the regional specific nature of intellectual tradition

The primary purpose of the study is to investigate the specifics of the intellectual tradition prevailing in some regions of the Late Antique world. For the purpose of a comprehensive review of the problem, the authors focus on wellknown intellectuals of the 5th-6th centuries, representing Gaul (Ausonius, Sidonius, Ennodius et al.), Alexandria (John Philoponus, Hypatia, Sinesius of Cyrene et al.), Africa (Fulgentius, Priscian, Corippus), Isauria (Candidus Isaurus

Palladium Nanoparticles–Polypyrrole Composite as Effective Catalyst for Fluoroalkylation of Alkenes

© 2018, Springer Science+Business Media, LLC, part of Springer Nature. Abstract: Palladium nanoparticles–polypyrrole composite (Pd/PPy) catalyzes the addition of perfluoroalkyl halides to olefins to produce a variety of products with good yields. An effective fluoroalkylation technique tested with various olefins, fluoroalkyl halides and Pd/PPy was developed. The reaction proceeds highly efficient under mild phosphine-free reaction conditions with different substrates, easy catalyst recycling and provides a general and straightforward access to fluoroalkylated products. Furthermore, we were able to control whether the addition of perfluoroalkyl occurs with various monomer (fluoroalkylated alkene or alkane with RF and OH moieties) or dimer formation (under electrochemical conditions). Graphical Abstract: [Figure not available: see fulltext.]

State of microcirculation and free-radical processes of periodontal tissues in smoking dependent patients with chronic generalized periodontitis associated with chronic hyperacid gastritis

The aim of the work was to determine the state of microcirculation and free radical processes of periodontal tissues in smoking dependent patients with chronic generalized periodontitis associated with chronic hyperacid gastritis. Materials and methods: We examined 90 patients (men and women) aged 25 to 44 years, who were divided into 3 groups: the first group - 48 smoking patients with chronic generalized periodontitis and chronic hyperacid gastritis associated with Helicobacter pylori; the second group - 22 patients with chronic generalized periodontitis and chronic hyperacid gastritis associated with Helicobacter pylori, without the bad habit; the third group - control, consisted of 20 healthy individuals. The smoking patients were randomly divided into two subgroups: patients of the first subgroup (G1.1) received the basic therapy of chronic generalized periodontitis and the proposed treatment and prevention complex; the patients in the second subgroup (G1.2) received basic therapy for chronic generalized periodontitis and ultraphonophoresis with placebo. Results: The use of treatment and prevention complex in smoking dependent patients and patients without the bad habit with chronic generalized periodontitis and chronic hyperacid gastritis associated with Helicobacter pylori demonstrated a positive dynamics of the functional characteristics of microcirculation and the balance in the lipid peroxidation – antioxidant system. Conclusions: So, the use of the proposed treatment and prevention complex had a positive effect on the state of microcirculation and free radical processes of periodontal tissues both at the near and long-term follow up, even under conditions of chronic hyperacid gastritis and the risk factor – smoking

ОБСЛЕДОВАНИЕ ГОРОДА КРАСНОКАМЕНСК НА СОДЕРЖАНИЕ РАДОНА В ПОМЕЩЕНИЯХ

Survey of dwellings and enterprises of the Krasnokamensk city on the indoor radon content were performed. The radon volume activity measurements were carried out by integral method with the help of track chambers. Chambers were exhibited in the heating and the warm periods of the year for the 3-4 months in the same premises. The values of equivalent equilibrium volume activity of radon and doses from radon were obtained. It is shown, that the situation with the radon irradiation of the population of Krasnokamensk city in general meets the requirements of the radiation safety standards. Seasonal relations of volume radon activity in the premises are presented.Проведено обследование жилых домов и учреждений города Краснокаменска на содержание радона в помещениях. Измерения объемной активности радона проводились интегральным методом с помощью трековых камер. Камеры экспонировали по 3–4 месяца в отопительный и теплый периоды года в одних и тех же помещениях. Получены значения эквивалентной равновесной объемной активности радона и доз от радона в помещениях. Показано, что ситуация с облучением населения г. Краснокаменска радоном в целом соответствует требованиям Норм радиационной безопасности. Представлены межсезонные отношения объемной активности радона в помещениях