Characteristics of hydrogen sensors based on thin tin dioxide films modified with gold

Effect of hydrogen in the concentration range from 10 to 2000 ppm on the characteristics of sensors based on thin films of tin dioxide modified with gold (Au/SnO2:Sb, Au) is studied in the thermo-cyclic mode at temperatures from 623 to 773 K and absolute humidity from 2.5 to 20 g/m3. Experimental data are discussed using expressions obtained within the framework of a model that takes into account the presence of three types of adsorbed particles (O¯, OH, and OH¯) on the surface of SnO2 nanocrystals. The characteristics of the sensors based on thin Pt/Pd/SnO2:Sb films (the first series) are compared with those of Au/SnO2:Sb, Au films (the second series). It is found that the degree of dissociation of molecular hydrogen into atoms during adsorption on the sensor under interaction with Au particles on the SnO2 surface is 4 times greater than that under interaction with Pt/Pd particles. The degree of dissociation of H2O molecules into hydrogen atoms and hydroxyl groups in pure moist air on the surface of the sensors of the second series is 1.6 times greater than that for the sensors of the first series. Thus, gold is a more effective stimulator of the dissociation of H2 and H2O molecules than platinum and palladium. A formula is obtained that describes more accurately the dependence of the response of the sensors of both series to the effect of hydrogen on the concentration of this gas and on the temperature of the measuring devices

Pheochromocytoma – clinical manifestations, diagnosis and current perioperative management

Pheochromocytoma is a neuroendocrine tumor characterized by the excessive production of catecholamines (epinephrine, norepinephrine, and dopamine). The diagnosis is suspected due to hypertensive paroxysms, associated with vegetative phenomena, due to the catecholaminergic hypersecretion. Diagnosis involves biochemical tests that reveal elevated levels of catecholamine metabolites (metanephrine and normetanephrine). Functional imaging, such as 123I-metaiodobenzylguanidine scintigraphy (123I-MIBG), has increased specificity in identifying the catecholamine-producing tumor and its metastases. The gold-standard treatment for patients with pheochromocytoma is represented by the surgical removal of the tumor. Before surgical resection, it is important to optimize blood pressure and intravascular volume in order to avoid negative hemodynamic events

Effect of long-term operation on energy band bending at the SnO2 microcrystals interfaces in thin tin dioxide films with various catalysts

This work presents the results of investigation of stability of energy band bending at the SnO2 microcrystals interfaces in thin films of tin dioxide with deposited Pt and Pd dispersed layers (Pt/Pd/SnO2:Sb) and with the additions of gold in the bulk and on the surface (Au/SnO2:Sb, Au) in long - term operation. Measurements of energy band bending were showed that the significantly variation of this value is observed in first month of the sensor using. Perhaps this phenomenon is caused by the surface reconstruction during operation of sensors and consequently by the increase of density of oxygen ions chemisorbed on the surface of tin dioxide

Gastrointestinal manifestations and dynamics of liver enzymes in children and adolescents with COVID-19 infection: A systematic review and meta-analysis

Objectives: To improve the knowledge on Coronavirus Disease (COVID-19) infection, we aimed to study the prevalence of gastrointestinal symptoms and the dynamics of liver enzymes in children infected with COVID-19. Methods: We performed a systematic search of all the articles published up to May 2020 in the following databases: PubMed-MEDLINE, Scopus, and Cochrane. We chose the fixed-or random-effect model for analysis based on the I2 statistic. The included data were analyzed to identify the prevalence of gastrointestinal symptoms (diarrhea, vomiting or nausea) and to identify the dynamics of liver enzymes in children and adolescents diagnosed with COVID-19. Results: We detected an overall prevalence of all gastrointestinal symptoms of 26 (95 CI: 0.18-0.35). The pooled prevalence of diarrhea and nausea/vomiting was 12 (95 CI: 0.08-0.16) with no heterogeneity (P = 0.19; I2 = 23.53) and 11 (95 CI: 0.05-0.17), respectively. The pooled prevalence of elevated ALT and AST and LDH was 12 (95 CI: 0.07-0.17), 14 (95 CI: 0.10-0.18) and 33 (95 CI: 0.12-0.54), respectively among the included studies. Conclusions: According to our systematic review and meta-analysis, 26 of the children and adolescents diagnosed with COVID-19 present gastrointestinal symptoms. This paper has provided a comprehensive overview of the prevalence of digestive symptoms of COVID-19 and of the liver enzymes dynamics in children and adolescents. © 2020, Author(s)

Pheochromocytoma – clinical manifestations, diagnosis and current perioperative management

Pheochromocytoma is a neuroendocrine tumor characterized by the excessive production of catecholamines (epinephrine, norepinephrine, and dopamine). The diagnosis is suspected due to hypertensive paroxysms, associated with vegetative phenomena, due to the catecholaminergic hypersecretion. Diagnosis involves biochemical tests that reveal elevated levels of catecholamine metabolites (metanephrine and normetanephrine). Functional imaging, such as 123I-metaiodobenzylguanidine scintigraphy (123I-MIBG), has increased specificity in identifying the catecholamine-producing tumor and its metastases. The gold-standard treatment for patients with pheochromocytoma is represented by the surgical removal of the tumor. Before surgical resection, it is important to optimize blood pressure and intravascular volume in order to avoid negative hemodynamic events

Effect of variety and processing method on functional properties of traditional sweet potato flour (“elubo”) and sensory acceptability of cooked paste (“amala”)

“Amala” is a generic term in Nigeria, used to describe a thick paste prepared by stirring flour (“elubo”) from yam, cassava or unripe plantain, in hot water, to form a smooth consistency. In order to overcome its high perishability and increase the utilization of sweet potato roots, three varieties of sweet potato roots were processed into flour using two methods. The interactive effect of variety and the processing method had a significant effect (P < 0.05) on all the functional properties of the flour except yellowness, setback viscosity, and peak time. Acceptable sweet potato “amala” with average sensory acceptability score of 7.5 were obtained from yellow-fleshed varieties irrespective of the processing method. Flour that produced acceptable “amala” were characterized by lower values of protein (2.20–3.94%), fiber (1.30–1.65%), total sugar (12.41–38.83 lg/mg), water absorption capacity (168–215 g/100 g), water solubility (8.29–14.65%), swelling power (0.52–0.82 g/g), and higher peak time (6.9–8.7 min)

Sequelae of COVID-19 at long-term follow-up after hospitalization

Aim. To assess long-term sequelae of COVID-19 in hospitalized patients at 3 to 7 months after discharge.Material and Methods. The whole of 700 patients hospitalized to the temporary COVID-19 treatment center hosted by the FSBI “National Medical Research Center of Cardiology” of the Ministry of Health of Russia from April to June 2020 were invited to participate in a follow-up study. At 3-7 months after the index hospitalization, patients or their proxies were contacted via telephone in order to obtain information on their vital status, cardiovascular and other conditions or their complications, and new hospitalizations. In addition, patients were invited to an outpatient visit under the "COVID-19-follow-up" program, encompassing physical examination and a comprehensive battery of laboratory and instrumental tests, including spirometry, chest computed tomography (CT) and the six minute walk test (6MWT). Further, dyspnea was assessed using the mMRC (Modified Medical Research Council) Dyspnea Scale. Results: We were able to contact 87.4% (612/700) of patients or their proxies. At follow-up, 4.4% (27) patients died, of which 96.3% (26) had cardiovascular diseases (CVD). A total of 213 patients aged 19 to 94 years old (mean age 56.8±12.5, median 57 years [49.0; 64.0]; men, 55.4%) agreed come for an outpatient visit and to participate in the “COVID-19-follow-up” program. Since discharge, 8% (17) of patients required new hospitalizations, and more than a half of these patients (58.8%; 10/17) had CVD-related hospitalizations. A total of 8.4% (18) patients experienced worsening of hypertension, 9 (4.2%) patients had newly diagnosed hypertension, 2 (0.9%) – coronary artery disease patients experienced new/recurrent angina symptoms. 4 (1.9%) patients had newly diagnosed coronary artery disease, and one patient had an ischemic stroke. At the outpatient visit, 114 (53.5%) patients had some symptoms, most frequently, shortness of breath (33%), fatigue (27.4%), chest pain (11.3%), and abnormal heartbeats (8.5%). Based on the mMRC Scale, 59% of patients had dyspnea of varying severity. Most patients had a normal vital capacity (VC), which was moderately reduced in 3.3% and severely reduced in 0.5% of patients. Chest CT scans were obtained in 78 (36.6%) patients, whose worst lung damage scores during hospitalization were CT3 or CT4. One in ten patients (10.8%) with severe lung damage during acute infection had persisting ground glass opacities, 35.9% developed fibrotic changes, 79.6% of patients had linear or fine focal opacities. According to the 6MWT data, 12.3% of patients walked less than 70% of the predicted distance, 67% walked 71 to 99% of the predicted distance, and 20.7% of patients were able to walk 100% of their predicted distance.Conclusion. These data suggest long-term negative sequelae of COVID-19 in more than half of hospitalized patients

The bone marrow compartment is modified in the absence of galectin-3

Galectin-3 (gal-3) is a β-galactoside binding protein present in multivalent complexes with an extracellular matrix and with cell surface glycoconjugates. In this context, it can deliver a variety of intracellular signals to modulate cell activation, differentiation and survival. In the hematopoietic system, it was demonstrated that gal-3 is expressed in myeloid cells and surrounding stromal cells. Furthermore, exogenous and surface gal-3 drive the proliferation of myeloblasts in a granulocyte–macrophage colony-stimulating factor (GM-CSF)-dependent manner. Here, we investigated whether gal-3 regulates the formation of myeloid bone marrow compartments by studying galectin-3−/− mice (gal-3−/−) in the C57BL/6 background. The bone marrow histology of gal-3−/− mice was significantly modified and the myeloid compartments drastically disturbed, in comparison with wild-type (WT) animals. In the absence of gal-3, we found reduced cell density and diaphyseal disorders containing increased trabecular projections into the marrow cavity. Moreover, myeloid cells presented limited capacity to differentiate into mature myeloid cell populations in gal-3−/− mice and the number of hematopoietic multipotent progenitors was increased relative to WT animals. In addition, bone marrow stromal cells of these mice had reduced levels of GM-CSF gene expression. Taken together, our data suggest that gal-3 interferes with hematopoiesis, controlling both precursors and stromal cells and favors terminal differentiation of myeloid progenitors rather than proliferation

СОПОСТАВЛЕНИЕ РЕЗУЛЬТАТОВ КОМПЬЮТЕРНОЙ ТОМОГРАФИИ И ВНУТРИСОСУДИСТОГО УЛЬТРАЗВУКОВОГО ИССЛЕДОВАНИЯ В ОЦЕНКЕ ПАРАМЕТРОВ АТЕРОСКЛЕРОТИЧЕСКИХ БЛЯШЕК КОРОНАРНЫХ АРТЕРИЙ

Purpose. To determine the possibilities of coronary CT-angiography (CTA) in evaluation of qualitative and qualitative parameters of coronary plaques in comparison with intravascular ultrasound (IVUS).Matherials and methods. 37 patients (29 men, 8 women) with symptoms of acute coronary syndrome (ACS) were included in the study. Unstable angina was detected in 24 patients, acute myocardial infarction (AMI) – in 13 patients. Averageage was 58 [44; 65] years. CTA had been performed as the first method of beam diagnostics in all cases if it was not necessary to use the emergency selective coronary angiography (CAG). IVUS was performed in one, two or three coronary arteries of every patient. Total, 60 coronary lesionsin 55 arteries were examined with IVUS. IVUS data was compared with CTA data.Results. Methods well correlated in detection of plaque burden (r = 0.823; p &lt; 0.0001), plaque length (r = 0.932, p &lt; 0.0001), remodeling index(RI) (r = 0.906; p &lt; 0.0001). Sensitivity and specificity of CTA in detection of irregular contour was 96.1% and 88.9% (area under ROC-curve 0.925), positive remodeling – 100% and 97.4% (area under ROC-curve 0.974). CTA and IVUS in evaluation of spotty calcinates was not coincide in 9 plaques, sensitivity and specificity of CTA in detection of 71% and 100% (area under ROC-curve 0.855).Discussion. Comparison of CTA and IVUS was performed in evaluation of plaques features in patients with ACS. This analysis showed high comparability of methods for evaluation of coronary stenosis degree, RI, plaque burden, length and contour. Thus, the characteristics of plaques according to CTA data can be used to stratify the risk of development of ACS.Conclusion. CTA – fast non-invasive method of coronary plaques evaluation. CTA correlates well with IVUS.Цель исследования: определить возможности КТ-ангиографии (КТА) в оценке количественных и качественных характеристик атеросклеротических бляшек (АСБ) в коронарных артериях по сравнению с данными внутрисосудистого ультразвукового исследования (ВСУЗИ).Материал и методы. В исследование было включено 37 пациентов (29 мужчин, 8 женщин), поступивших в отделение неотложной кардиологии с клинической картиной острого коронарного синдрома (ОКС), из которых у 24 диагностирована нестабильная стенокардия, у 13 – острый инфаркт миокарда. Средний возраст больных составил 58 [44; 65] лет. Всем пациентам первым из лучевых методов исследования была выполнена КТА коронарных артерий при отсутствии необходимости экстренного проведения инвазивной коронарной ангиографии. Каждому из 37 пациентов ВСУЗИ было выполнено в одной, двух или трех коронарных артериях. Всего с помощью ВСУЗИ обследовано 60 измененных участков в 55 коронарных артериях. Данные ВСУЗИ сравнивались с результатами КТА.Результаты. Корреляционный анализ показал высокую сопоставимость методов в определении бремени бляшки (r = 0,823; p &lt; 0,0001), протяженности бляшки (r = 0,932; p &lt; 0,0001), индекса ремоделирования (ИР) (r = 0,906; p &lt; 0,0001). Чувствительность и специфичность метода в выявлении неровности контура составили 96,1 и 88,9% (площадь под кривой 0,925), положительного ремоделирования – 100 и 97,4% (площадь под кривой 0,974) соответственно. При оценке точечных кальцинатов в 9 мягких бляшках данные КТА не совпадали с данными ВСУЗИ. а чувствительность и специфичность метода составили 71 и 100% (площадь под кривой 0,855) соответственно.Обсуждение. В представленной работе впервые в нашей стране проведен сравнительный анализ состояния бляшек в коронарных артериях по данным КТА и ВСУЗИ у больных с ОКС, который показал высокую сопоставимость методов для определения степени стенозирования просвета коронарных артерий, ИР, бремени, протяженности и контуров бляшки. Таким образом, характеристики АСБ по данным КТА можно использовать для стратификации риска развития ОКС.Заключение. КТА является быстрым неинвазивным методом оценки состояния АСБ. Результаты КТА хорошо коррелируют с данными ВСУЗИ