Effect of Al2O3 and CaF2 additives on the viscosity of conventional cryolite melts

The viscosity of cryolite melts of conventional composition NaF–AlF3–CaF2–Al2O3 was studied by rotational viscometry using the FRS 1600 high-temperature rheometer. The cryolite ratio of the NaF–AlF3 melt was 2.1, 2.3, and 2.5; the Al2O3 content varied from 2 to 6.6, and CaF2 – from 0 to 8 wt%. The measurements were carried out in the temperature range from liquidus to 1200 °C. The conditions for the laminar flow of the investigated melts were determined, based on the measurements of the cryolite melts viscosity as a function of the shear rate at a constant temperature. A shear rate of 12 ± 1 s–1 was chosen for studying the viscosity temperature dependence for all samples. The viscosity temperature dependence of cryolite melts is described by a linear equation. The temperature coefficient b in this equation has negative values and varies in the range of (–0.01)–(–0.06) mPa·s/deg. It was found that the viscosity of cryolite melts of conventional composition in the range of operating temperatures of aluminum electrolysis (950–970 °C) varies from 2.5 to 3.7 mPa·s (depending on the composition and temperature). The viscosity of cryolite-alumina melts increases with the rise of alumina content: 1 wt% Al2O3 increases the viscosity, on average, by 1%. However, the influence of CaF2 is more significant: the addition of 1 wt% CaF2 leads to an increase in viscosity by 3%. A decrease in the CR of the melt by 0.1 (in the range of 2.1–2.5) leads to a decrease in the viscosity of cryolite melts by 2.3%. A viscosity regression equation for the cryolite melts of conventional composition as a function of several independent parameters (temperature, CR, CaF2 and Al2O3 content) is obtained by the multivariable approximation of experimental data. The equation satisfactorily (within 1.5%) describes the viscosity of conventional industrial electrolytes and can be used for estimation of their viscosity

Borated graphite cathodes for low-temperature aluminum electrolysis

Electrochemical boriding of the graphite plates in the potassium cryolite based electrolytes was studied. The boriding were carried out in a cell with vertical electrodes. The procedure included 2 stages: 1) electrolysis in the KF–AlF3–KBF4 melt (CR=1.3) at low current density (0.01–0.02 A/cm2), required for the boron reduction, at 700 and 750 °C; 2) electrolysis in the KF–AlF3–Al2O3 melt at higher current density (0.2 A/cm2), required for the aluminum reduction. The optimal conditions of electrodeposition for obtaining the borated wettable cathodes were determined. According to the SEM data, a continuous AlB2 layer with a thickness of 7–10 μm was formed on the graphite surface. The borated graphite was tested as a wetted cathode during the low-temperature aluminum electrolysis. Prolonged electrolysis in a vertical cell with the graphite anode and the borated graphite cathode was carried out in the KF–NaF(10 wt.%)–AlF3–Al2O3 electrolyte (CR=1.5) at 830 °C. After 100 h of electrolysis, the thickness of the AlB2 layer on the graphite surface was 5 μm, while the cathode surface was completely wetted with aluminum. Thus, we demonstrated the feasibility of using the borated graphite cathode as a wettable dripping cathode in the low-temperature aluminum electrolysis in the vertical cell

Malnutrition as a factor aggravating the heart failure course in the elderly and senile age

Cardiovascular diseases are the main death causes in the modern world. Heart failure (HF) is the terminal stage of most cardiovascular diseases. The prevalence of HF is increasing in patients of older age groups. At the same time, the number of geriatric syndromes increases with age, one of which is malnutrition. Recent studies demonstrate the mutually aggravating effect of heart failure and malnutrition, and that the correction of malnutrition can improve the heart failure course. The introduction of screening and timely correction of malnutrition will reduce the hospitalization and mortality rates in geriatric patients with HF

EFFICACY AND SAFETY OF LIPID-LOWERING DRUGS IN PRIMARY AND SECONDARY PREVENTION OF CARDIOVASCULAR DISEASES IN THE ELDERLY

Effect of hyperlipidemia on morbidity and mortality in elderly patients is considered. Authors also cover issues of efficacy and safety of lipid-lowering therapy in primary and secondary prevention of cardiovascular diseases in patients ≥80 years of age who are the most quickly growing group of population and have the highest cardiovascular risk. They stress the need to take into account polymorbidity and polypharmacy that increase the risk of adverse reactions due to the use of both statins and their drug-drug interactions, which requires an assessment of risk/benefit ratio. In addition, there is a need for development of reliable prognostic tools to predict relevant outcomes (e.g., stroke, decrease in functionality/independence, quality of life reduction) and rationales for lipid-lowering therapy in the elderly and also their adherence to treatment

Features of pharmacotherapy in the elderly patients. Introduction to the problem

Features of pharmacotherapy in the elderly patients are discussed. Data on the pharmacokinetics and pharmacodynamics, comorbidity, polypragmasy and treatment adherence among patients of this age group are presented

Получение лигатуры Al–B алюмотермическим восстановлением KBF4и B2O3 в среде расплавленных солевых флюсов

The study covers the process of obtaining the Al–B master alloy by the KBF4and B2O3aluminothermic reduction using KF–AlF3and KF–NaF–AlF3fluoride fluxes at 983 and 1123 К, respectively, and KCl–NaCl–KF chloride-fluoride fluxes at Т= 1173÷1223 К. All experiments were carried out under the same conditions: molten mixture stirring rate was 400 rpm, synthesis duration was 30min. The maximum amount of boron (1,5 %) in the Al–B alloy was obtained when using KBF4(3 % per B) as a boron-containing raw material in the KF–AlF3medium with a molar (cryolite) ratio (CR) of KF/AlF3equal to 1,3, atТ= 983 К, while boron recovery ratio did not exceed 75 %. Comparable results were obtained in experiments with KF–NaF–AlF3f lux (CR = 1,5) at Т= 1123 К. However, with the increased concentration of fed boron its recovery ratio decreased substantially. It is connected with the higher decomposition temperature of not only KBF4, but also less thermally stable NaBF4 formed as a result of exchange reaction in the melt. Therefore it is not recommended to use sodium salts as a f lux component. The Al–B master alloys obtained by KBF4reduction in fluoride fluxes were solid solutions of B in Al containing the AlB2intermetallic compound. The lowest amount of boron in aluminum with the minimum degree of extraction was obtained in experiments with the B2O3in molten KF–AlF3with CR = 1,5. Nevertheless, the results of scanning electron microscopy indicate a uniform distribution of B over the Al matrix and the absence of intermetallic compounds, while a large amount of Al2O3was found, which is the product of B2O3reactions with both liquid Al and KF–AlF3flux.Исследован процесс получения лигатуры Al–B методом алюмотермического восстановления KBF4и B2O3с использованием фторидных флюсов KF–AlF3и КF–NaF–AlF3при температурах, соответственно, 983 и 1123 К и хлоридно-фторидных флюсов KCl–NaCl–KF при Т= 1173÷1223 К. Все эксперименты проводили при одинаковых условиях: скорость перемешивания расплавленной смеси – 400 об/мин, длительность синтеза – 30 мин. Максимальное количество бора (1,5 %) в сплаве Al–B было получено в случае применения в качестве борсодержащего сырья KBF4(3 % в расчете на В) в среде KF–AlF3с мольным (криолитовым) отношением (КО) компонентов KF/AlF3, равным 1,3, при Т= 983 К, при этом степень извлечения бора не превышала 75 %. Сравнимые результаты были получены в экспериментах с флюсом KF–NaF–AlF3(КО = 1,5) при Т= 1123 К. Однако при увеличении концентрации задаваемого бора степень его извлечения существенно снижалась, что связано с разложением при более высокой температуре не только KBF4, но и менее термически устойчивого NaBF4, который образуется в результате обменной реакции в расплаве. Поэтому не рекомендуется использование солей натрия в качестве компонента флюса. Лигатуры Al–B, полученные восстановлением KBF4в среде фторидных флюсов, представляли собой твердые растворы бора в алюминии, содержащие интерметаллид AlB2. Наименьшее количество бора в алюминии с минимальной степенью извлечения было получено в опытах с B2O3в среде расплавленного KF–AlF3с КО = 1,5. Тем не менее результаты сканирующей электронной микроскопии свидетельствуют о равномерном распре-делении B в матрице Al и отсутствии интерметаллидов, при этом найдено большое количество оксида Al2O3, который является продуктом реакций B2O3как с жидким Al, так и с флюсом KF–AlF3

ВЛИЯНИЕ УСЛОВИЙ КРИСТАЛЛИЗАЦИИ НА СТРУКТУРУ И МОДИФИЦИРУЮЩУЮ СПОСОБНОСТЬ Al–Sc-СПЛАВОВ

The study covers the impact of thermo-time processing and cooling rate of molten metal on the crystallization regularities, structure, properties and modifying ability of Al–Sc alloys. The Al–Sc alloys obtained by electrolysis in the KF–NaF–AlF3–Sc2O3 melts at 820–850 °C were used as an initial charge for casting. It was found that changes in overheat values and casting temperatures make it possible to vary the shape, number and size of crystals in a wide range. The modifying effect of the cast and fast-quenched master alloys and alloy produced by electrolysis was tested on Al–4,5%Cu alloys. The greatest refinement of the Al–4,5%Cu–0,4%Sc alloy structure was obtained with the fast-quenched master alloy.Исследовано влияние режимов термовременной обработки и скорости охлаждения металлических расплавов на закономерности кристаллизации Al–Sc-сплавов, их структуру, свойства и модифицирующую способность. В качестве исходной шихты для литья использовали отливки Al–Sc-сплавов, полученные электролизом солевых расплавов KF–NaF– AlF3–Sc2O3 при 820–850 °С. Установлено, что, меняя величину перегрева расплава и температуру литья, можно в широких пределах варьировать форму, количество и размеры кристаллов. Модифицирующее действие литой и быстрозакаленной лигатур, а также лигатурного сплава, полученного электролизом, протестировано на сплавах Al–4,5%Cu. Наибольший эффект измельчения структуры сплава Al–4,5%Cu–0,4%Sc был достигнут при использовании быстрозакаленной лигатуры

Diagnosis and Treatment of Elderly and Senile Chronic Constipation: an Expert Consensus

Aim. An appraisal of practitioners with chronic constipation management details in older and senile adults.Key points. Chronic constipation is a common issue in geriatrics. Aside to age-related physiological bowel disfunction, a higher constipation incidence is conditioned by declined physical activity and frailty, polypharmacy and a series of secondary constipation-developing chronic states and diseases. Chronic constipation is associated with a higher risk of cardiovascular disease and complications, impaired general perception of health and pain, growing alarm and depression, and reduced quality of life. The treatment tactics in chronic constipation is cause-conditioned and should account for the patient’s history and therapy line, overall clinical condition, cognitive status and functional activity level. An essential baseline aspect of constipation management is apprising the patient and his family of the underlying factors and methods for non-drug and drug correction. An higher-fibre diet is recommended as first measure, with osmotic laxatives added and titrated to clinical response if none observed towards the non-drug and high-fibre regimens. Stimulant laxatives and prokinetics should be recommended in patients reluctant to fibre supplements and osmotic laxatives. Subsidiary correction includes biofeedback, transanal irrigation, acupuncture, foot reflexology and percutaneous tibial nerve stimulation.Conclusion. Elderly and senile chronic constipation is a prevalent multifactorial state requiring an efficient management via assessment and correction of total risk factors and consistent use of non-medication and drug therapies

Особенности гериатрического статуса у пожилых пациентов с остеоартритом в сочетании с невропатической болью: данные российского эпидемиологического исследования ЭВКАЛИПТ

The main symptoms of osteoarthritis (OA) are pain and dysfunction of the joints. Neuropathic pain (NP) occurs in more than half of patients with OA, it is refractory in nature and is the cause for seeking medical advice more frequently, poor quality of life and disability.Objective: to evaluate the frequency of NP and its relationship with geriatric syndromes (GS) in patients with OA aged 65 years and older. Patients and methods. The subanalysis of the study EVKALIPT included 2286 patients with OA and chronic pain syndrome. All patients underwent a comprehensive geriatric assessment (CGA) and diagnostics of NP using the DN4 questionnaire.Results and discussion. The prevalence of NP in patients with OA was 22.7%. Patients with OA and NP more often experienced pain of any localization with a large number of tender points, they had a higher frequency and intensity of pain syndrome, they more often took analgesics and noted limitations in daily life. When conducting a correlation analysis, correlations of medium strength were found between the sum of scores according to DN4 questionnaire and the pain intensity assessment on a numerical rating scale at the time of examination (r=0.26; p<0.001) and in the previous 7 days (r=0.29; p<0.001). CGA data in patients with OA and NP demonstrated worse geriatric status and a higher incidence of GS. The most common GSs were basic (81%) and instrumental (64%) dependence in everyday life, senile asthenia (70%), urinary incontinence (69%), depression (69%) and cognitive impairment (67%). Multivariate analysis showed that, in addition to age, the presence of NP was independently associated with sensory deficits, depression, falls, urinary incontinence, and bedsores (odds ratio 1.77–2.49). Patients with NP were more likely to use mobility aids, absorbent underwear, and orthotics.Conclusion. NP was diagnosed in 22.7% of OA patients aged 65 years and older. Such patients have worse functional status, they are more often diagnosed with a number of GSs.Главные симптомы остеоартрита (ОА) – боль и нарушение функции суставов. Невропатическая боль (НБ) встречается более чем у половины больных ОА, носит рефрактерный характер и является причиной более частого обращения за медицинской помощью, низкого качества жизни и инвалидизации.Цель исследования – оценить частоту НБ и ее взаимосвязь с гериатрическими синдромами (ГС) у пациентов с ОА в возрасте 65 лет и старше.Пациенты и методы. В субанализ исследования ЭВКАЛИПТ включено 2286 пациентов с ОА и хроническим болевым синдромом. Всем больным проведены комплексная гериатрическая оценка (КГО) и диагностика НБ с помощью опросника DN4.Результаты и обсуждение. Распространенность НБ у пациентов с ОА составила 22,7%. Пациенты с ОА и НБ чаще испытывали боль любой локализации с большим количеством болевых точек, у них были выше частота и интенсивность болевого синдрома, они чаще принимали анальгетики и отмечали ограничения в повседневной жизни. При проведении корреляционного анализа обнаружены взаимосвязи средней силы между суммой баллов по опроснику DN4 и оценкой интенсивности боли по числовой рейтинговой шкале в момент осмотра (r=0,26; p<0,001) и в предшествующие 7 дней (r=0,29; p<0,001). Данные КГО у пациентов с ОА и НБ продемонстрировали худший гериатрический статус и более высокую частоту ГС. Наиболее распространенными ГС были базовая (81%) и инструментальная (64%) зависимость в повседневной жизни, старческая астения (70%), недержание мочи (69%), депрессия (69%) и когнитивные нарушения (67%). Многофакторный анализ показал, что с наличием НБ, помимо возраста, независимо ассоциированы сенсорный дефицит, депрессия, падения, недержание мочи и пролежни (отношение шансов 1,77–2,49). Пациенты с НБ чаще использовали вспомогательные средства для облегчения мобильности, абсорбирующее белье и ортопедические изделия.Заключение. НБ диагностирована у 22,7% пациентов с ОА в возрасте 65 лет и старше. Такие больные имеют худший функциональный статус, у них чаще диагностируется ряд ГС