817 research outputs found

    Polymethacrylate Colorimetric Sensor for Evaluation of Total Antioxidant Capacity

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    A new colorimetric sensor using an immobilized chromogenic redox reagent was devised for measuring the total antioxidant level in a liquid sample without requiring sample pretreatment. The reagent, Fe(III) – 1,10-phenanthroline (Fe(III)-phen), was immobilized into a polymethacrylate matrix (PMM), and the absorbance changes associated with the formation of the highly colored Fe(II)-phen chelate as a result of reaction with antioxidants was measured at 510 nm. The developed optical sensor was used to screen total antioxidant capacity of some black and green teas, red and white wines

    Solid Phase Sorption of Phenols on Metals Acetylacetonates

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    The solid phase extraction properties of surface layers of Eu(III), Al(III), Fe(III), Cr(III) acetylacetonates are compared for sorption some phenols and chlorophenols. The effects of the energies of adsorption and complexation on the retention of various sorbates were calculated. GC methods with preconcentration are proposed to evaluate phenols by means of solid-phase extraction on a sorbent with a surface layer of Eu acetylacetonate with extraction effectiveness of 85%

    Solid-phase spectrophotometric iodometric determination of nitrite and selenium(IV) using a polymethacrylate matrix

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    Procedures for the iodometric solid-phase spectrophotometric determination of nitrite and selenium( IV) using a polymethacrylate matrix are proposed. The procedures are based on the reaction of nitrite and selenium(IV) with iodine in an acidic medium with the release of free iodine in amounts equivalent to those of the substances to be determined, extraction of the iodine formed with a polymethacrylate matrix, and measurement of absorbance of the matrix at 370 nm. The developed procedures ensure the determination of 0.01–0.12 mg/L of nitrite and 0.05–0.40 mg/L of selenium(IV) with limits of detection of 0.005 and 0.03 mg/L, respectively. It was shown that the proposed procedures can be applied to the determination of selenium(IV) in mineral water and nitrites in vegetables and soil

    Manganese catalysts to obtain olefins from C1-C4 alkanes

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    Oxidative transformations of C1-C4 alkanes into olefins on oxide manganese catalysts were under study. We also studied oxidative coupling of methane (OCM) into ethylene on deposited and applied on the silicon dioxide catalysts. We studied the influence of chemical composition of catalyst and promotors on the OCM. Adding a little amount of ethane and propane hydrocarbons to methane allows increasing the concentration of ethylene in gases and significantly increasing productivity in ethylene. The study also shows the impact of the amount of manganese and promotors applied on SiO2 on the yield of olefins during the conversion of C3-C4 alkanes

    THE INITIAL STAGE OF TESTING THE DEVELOPED APPARATUS TO DETERMINE THE INTERNATIONAL NORMALIZED RATIO

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    Протромбиновое время (ПТВ) – это лабораторный показатель, позволяющий оценить внешний путь свертывания крови (активность факторов I, II, V, VII и X). Для стандартизации результатов теста ПТВ введен показатель МНО. МНО = (ПТВ пациента/ПТВ 100%)МИЧ. Набирает популярность контроль МНО с помощью портативных коагулометров. На российском рынке представлены: CoaguChek XS, qLabs Electrometer. Главная проблема − их высокая стоимость и дороговизна в эксплуатации. Российские ученые давно задались вопросом импортозамещения. Однако, в литературе нет информации о тестировании разработок. При разработке экспериментальной модели для измерения МНО и ПТВ, мы руководствовались результатами литературного поиска по наукометрическим базам данных Elibrary, Scopus, PubMed и WoS с учетом предполагаемой стоимости разрабатываемой модели.Цель исследования. Провести начальный этап тестирования экспериментальной модели с сопоставлением полученных результатов с данными сертифицированной лаборатории.Материал и методы. Обследовано 70 пациентов (26 мужчин и 44 женщины), принимающих «Варфарин». Материал для измерения экспериментальной моделью – капиллярная кровь. В качестве тест-системы применяли тест-полоску qLabs® PT-INR Test Strip.Результаты. Разница ПТВ тестируемой модели и результатов сертифицированной лаборатории ± 1–2 секунды. ПТВ Протромбин-калибратора 13 сек. Протромбиновое отношение Протромбин-калибратора 1,0. Пациент №1. ПТВ на тестируемом аппарате 34 сек. МИЧ тробопластина на тест-полоске 1,0. МНО = (34 сек /13 сек × 1,0)1,0 = 2,62. Результат сертифицированной лаборатории: ПТВ 36 сек, МНО 2,86. Пациент №2. ПТВ на тестируемом аппарате 31 сек. МНО = (31 сек/13 сек × 1,0)1,0 = 2,38. Результаты сертифицированной лаборатории: ПТВ 32 сек, МНО 2,48.Вывод. Согласно представленным результатам, полученным в ходе тестирования разработанной портативной модели у пациентов, находящихся на варфаринотерапии, получены сопоставимые результаты ПТВ и МНО сертифицированной лабораторией.Prothrombin time (PTT) is a laboratory indicator that allows to evaluate the external pathway of blood coagulation (activity of factors I, II, V, VII and X). An INR indicator was introduced to standardize the results of the PTV test. INR = (patient’s PTT/PTT norm) ISI. The control of the INR is gaining popularity with the help of portable coagulometers. On the russian market are CoaguChek XS, qLabs Electrometer. The main problem is their high cost and high cost of operation. Russian scientists have long wondered about import substitution. However, in the literature there is no information on testing development. When developing an experimental model for measuring INR and PTV, we were guided by the results of the literary search in the scientometric databases Elibrary, Scopus, PubMed and WoS, taking into account the estimated cost of the developed model.Background. To conduct the initial stage of testing an experimental model with a comparison of the results obtained with the data of a certified laboratory.Materials and methods. We examined 70 patients (26 men and 44 women) taking «Warfarin». The material for measuring the experimental model was capillary blood. We used the qLabs® PT-INR Test Strip as a test system.Results. We obtained the Difference of the PTT of the tested model and the results of the certified laboratory ± 1–2 seconds. PTT prothrombin calibrator was 13 sec. Prothrombin ratio prothrombin calibrator was 1.0. Patient №1. PTT on the tested device 34 seconds. ISI troboplastin on test strip was 1.0. INR = (34 sec / 13 sec × 1.0)1.0 = 2.62. The result of a certified laboratory: PTT 36 sec, INA 2.86. Patient №2. PTT on the tested device 31 sec. INR = (31 sec / 13 sec × 1.0)1.0= 2.38. The results of the certified laboratory: PTT 32 sec, INR 2.48.Conclusions. According to the presented results obtained during testing of the developed portable model in patients on warfarin therapy, comparable results of PTT and INA were obtained with a certified laboratory

    Increasing Availability of the International Normalized Ratio Control in Russia

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    Background: Warfarin is still, in some cases, the only medication to prevent thromboembolic complications. Warfarin intake imposes regular INR monitoring, which can be performed domiciliary. Currently, in the Russian market, there are two models of automatic portable blood coagulometers: CoaguChek XS (Germany) and qLabs ElectroMeter (China). The main problem of portable coagulometers is their high cost and high cost of operation, which the majority of patients cannot afford. To explore the demand for development of a Russian coagulometer with a more affordable price, a questionnaire survey was carried out among the patients who needed this device. Methods and Results: We surveyed 70 patients taking Warfarin, with 5 years duration paroxysmal, persistent/or stable AF of nonvalvular etiology, having >2 CHADS-VASc score for thrombembolia risk assessment and <3 HAS-BLED score for hemorrhage risk assessment. According to the survey results, 7 (10%) patients had portable coagulometers, including 3 persons with CoaguChek XS and 4 persons with Micropoint qLabs ElectroMeter. Among these patients, there were 4 persons who continued regular INR monitoring domiciliary, while 3 patients had financial difficulties in getting testing strips. At the same time, 14 (20%) patients were not aware of the possibility of domiciliary INR monitoring. As it turned out, those patients who received regular INR monitoring domiciliary with a portable coagulometer, or at their local polyclinics, had neither ischemic strokes nor hemorrhages within a period of five years. Conclusion: It is critical to develop and manufacture a domestic equivalent of a portable coagulometer and testing strips for household use at a more affordable price
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