Comparison of the accuracy of resting metabolic rate in children with simple obesity using calculation formulas and indirect respiratory calorimetry

BACKGROUND: A prerequisite for planning a diet for weight loss in obese children is to determine the level of resting metabolic rate (RMR). The gold standard for estimating the daily energy consumption of rest is indirect respiratory calorimetry. However, given its high cost and labor intensity, various calculation formulas are widely used in clinical practice. AIMS: to determine the accuracy of resting metabolic rate estimated by calculation formulas and indirect respiratory calorimetry in children with simple obesity. MATERIALS AND METHODS: The study included 100 children aged 9 to 18 years, with a «simple» constitutional-exogenous obesity, which assessed the resting metabolic rate estimated by calculation formulas and indirect respiratory calorimetry. RESULTS: The Molnar formula most accurately estimates resting metabolic rate, comparable to the results of indirect respiratory calorimetry in 64% of cases. The Harris-Benedict and IOM formulas yield an accurate result in 53 and 51% of the cases, respectively. The least accurate result is shown by WHO formula (22%). The minimum mean difference between the calculated and actual basal metabolic rate in obese boys for the Molnar formula is 18 kcal (CI: -53 to 90, 95% LOA from -490 to 527), in girls: -0.7 kcal (CI) : -65 - 63, 95% LOA from -435 to 434). Attention is drawn to the large mean difference and wide spread of the boundaries of the agreement of the studied indicators in obese children. In the evaluation, depending on the degree of obesity, it is shown that the formula Molnar has the highest accuracy, however, in children with morbid obesity, the accuracy of the evaluation is significantly reduced. CONCLUSIONS: Indirect respiratory calorimetry is the preferred method of assessing resting metabolic rate in children with simple obesity

Особенности синтеза триамилцитрата

Objectives. To find an effective way for obtaining triamyl citrate, an environmentally friendly, biodegradable citric acid ester used as a plasticizer for PVC-based polymer compositions.Methods. The possibilities of heterogeneous catalysis were analyzed using the case study of three commercial samples of macroporous sulfocationites (Amberlyst™ 15, Amberlyst™ 70, and TULSION® 66). Homogeneous catalysis was studied using the example of orthophosphoric acid (H3PO4), while self-catalysis was investigated during esterification of citric acid with amyl alcohol (ROH). The syntheses were carried out under identical conditions: T = 110 °C, the ratio of CA:ROH = 1:5 (mol) amount of catalyst 1 wt % on the reaction mass in a thermostatically controlled reactor of ideal mixing with continuous distillation of the resulting water.Results. It was found that in all variants (even under self-catalysis conditions), the conversion of citric acid in 180 min reached 94–99%. Triamyl citrate was formed after 9 h with a yield of 90% only when using a homogeneous catalyst (H3PO4) and in the presence of a heterogeneous catalyst sample (Amberlyst ™ 15).Conclusions. The revealed differences in the reactivity of the studied sulfocationites (Amberlyst™ 15, Amberlyst ™ 70, and TULSION® 66) confirm the well-known theoretical positions, according to which the kinetic pseudo-homogeneous model of the esterification process of hydroxy acids in excess of aliphatic alcohols is based on the law of acting masses and depends on the specific surface area of the catalyst, which for Amberlyst ™ 15 is of the greatest importance as compared to Amberlyst ™ 70 and TULSION® 66 (m2/g): 53:36:35, respectively.Цели. Поиск эффективного метода получения триамилцитрата – экологически чистого, биоразлагаемого сложного эфира лимонной кислоты, используемого в качестве пластификатора полимерных композиций на основе поливинилхлорида.Методы. Выявлены возможности гетерогенного катализа на примере трех коммерческих образцов макропористых сульфокатионитов (Амберлист™ 15, Амберлист™ 70 и Тулсион® 66); гомогенного катализа на примере ортофосфорной кислоты (H3PO4) и самокатализа при этерификации лимонной кислоты (ЛК) амиловым спиртом (ROH). Синтезы проводили в одинаковых условиях: T = 110 °С отношение ЛК:ROH = 1:5 (мольн.) количество катализатора 1 мас. %. на реакционную массу в термостатированном реакторе идеального смешения с непрерывным отгоном образующейся воды.Результаты. Установлено, что во всех вариантах конверсия лимонной кислоты за 180 мин достигает 94–99%. Триамилцитрат с выходом 90% образуется через 9 ч только при использовании гомогенного катализатора (H3PO4) и в присутствии образца гетерогенного катализатора – Амберлист™ 15.Выводы. Выявленные различия в реакционной способности исследованных сульфокатионитов Амберлист™ 15, Амберлист™ 70 и Тулсион® 66 подтверждают известные теоретические положения, в соответствии с которыми кинетическая псевдогомогенная модель процесса этерификации гидроксикислот в избытке алифатических спиртов основывается на законе действующих масс и зависит от удельной поверхности катализатора, которая для Амберлист™ 15 имеет наибольшее значение по сравнению с Амберлист™ 70 и Тулсион® 66 (м2/г): 53:36:35 соответственно

Theory of rotating electrohydrodynamic flows in a liquid film

The mathematical model of rotating electrohydrodynamic flows in a thin suspended liquid film is proposed and studied. The flows are driven by the given difference of potentials in one direction and constant external electric field E-out in another direction in the plane of a film. To derive the model, we employ the spatial averaging over the normal coordinate to a film that leads to the average Reynolds stress that is proportional to vertical bar E-out vertical bar(3). This stress generates tangential velocity in the vicinity of the edges of a film that, in turn, causes the rotational motion of a liquid. The proposed model is used to explain the experimental observations of the liquid film motor

Региональные особенности современных изменений зимней аккумуляции снега на севере Евразии по данным наблюдений, реанализа и спутниковых измерений

The paper presents data on winter snow accumulation on the Russian territory obtained from different sources: ground measurements of snow depth on meteorological stations, water snow equivalent calculated from data of route surveys, reanalysis, and satellite observations. Three large regions were isolated which are distinguished by characters of the snow depth fluctuations and their long-term tendencies. Comparison of the trends calculated from data of reanalysis and satellite measurements demonstrated essential disagreement of them with data of in situ observations.Рассматриваются данные о зимней аккумуляции снега на территории России из разных источников: наземных наблюдений за толщиной снежного покрова на метеостанциях; водного эквивалента снега по данным маршрутной съёмки, а также реанализа и спутниковых измерений. Выделено три крупных района, отличающихся по характеру колебаний толщины снега и их многолетним тенденциям. Сравнение этих трендов, полученных по данным реанализа и спутниковых измерений, указывает на их существенные расхождения с данными наблюдений