421 research outputs found

    Charge Localization and Ordering in A2_2Mn8_8O16_{16} Hollandite Group Oxides: Impact of Density Functional Theory Approaches

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    The phases of A2_2Mn8_8O16_{16} hollandite group oxides emerge from the competition between ionic interactions, Jahn-Teller effects, charge ordering, and magnetic interactions. Their balanced treatment with feasible computational approaches can be challenging for commonly used approximations in Density Functional Theory. Three examples (A = Ag, Li and K) are studied with a sequence of different approximate exchange-correlation functionals. Starting from a generalized gradient approximation (GGA), an extension to include van der Waals interactions and a recently proposed meta-GGA are considered. Then local Coulomb interactions for the Mn 3d3d electrons are more explicitly considered with the DFT+UU approach. Finally selected results from a hybrid functional approach provide a reference. Results for the binding energy of the A species in the parent oxide highlight the role of van der Waals interactions. Relatively accurate results for insertion energies can be achieved with a low UU and a high UU approach. In the low UU case, the materials are described as band metals with a high symmetry, tetragonal crystal structure. In the high UU case, the electrons donated by A result in formation of local Mn3+^{3+} centers and corresponding Jahn-Teller distortions characterized by a local order parameter. The resulting degree of monoclinic distortion depends on charge ordering and magnetic interactions in the phase formed. The reference hybrid functional results show charge localization and ordering. Comparison to low temperature experiments of related compounds suggests that charge localization is the physically correct result for the hollandite group oxides studied here. . . .Comment: 16 pages, 8 figure

    Проект реконструкции системы теплоснабжения города Междуреченска.

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    Проект перевода системы теплоснабжения микрорайона «жилмассив железнодорожного вокзала» города Междуреченска c открытой на закрытую содержит расчёт тепловых нагрузок на отопление, горячее водоснабжение и вентиляцию, расчёт расхода сетевой воды на отопление, горячее водоснабжение и вентиляцию, суммарный расчетный расход сетевой воды в двухтрубных тепловых сетях в закрытых системах теплоснабжения при качественном регулировании отпуска теплоты. Выполнен расчёт двухступенчатых подогревателей ГВС, подбор циркуляционных насосов, определение толщины изоляции водонагревателей МТП и подводящих трубопроводов, объёмно-планировочные решения и компоновка оборудования МТП. Приведён проверочный гидравлический расчет тепловых сетей, наладка присоеди-ненных систем, автоматизация тепловых пунктов, охрана труда при рекон-струкции и ремонте МТП. Технико-экономическое обоснование.heating systems Translation Project neighborhood "zhilmassiv train station" of the city of Mezhdurechensk c open the closed contains a calculation of the heat load for heating, hot water and ventilation, the power flow calculation for heating, hot water and ventilation, the total current consumption of mains water in two-pipe heating networks in closed heating systems with qualitative regulation of heat supply. Calculations of the two-stage heaters hot water, circulating pumps selection, determining the thickness of insulation and water heaters ICC supply lines, volumetric-planning solutions and equipment layout of the ICC. The above test hydraulic calculation of heating networks, setting up United adjunction-systems, automation heating units, labor protection at the recon-struction and repair of the ICC. Feasibility study

    Liver transplantation for glycogen storage disease types I, III, and IV

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    Glycogen storage disease (GSD) types I, III, and IV can be associated with severe liver disease. The possible development of hepatocellular carcinoma and/or hepatic failure make these GSDs potential candidates for liver transplantation. Early diagnosis and initiation of effective dietary therapy have dramatically improved the outcome of GSD type I by reducing the incidence of liver adenoma and renal insufficiency. Nine type I and 3 type III patients have received liver transplants because of poor metabolic control, multiple liver adenomas, or progressive liver failure. Metabolic abnormalities were corrected in all GSD type I and type III patients, while catch-up growth was reported only in two patients. Whether liver transplantation results in reversal and/or prevention of renal disease remains unclear. Neutropenia persisted in both GSDIb patients post liver transplantation necessitating continuous granulocyte colony stimulating factor treatment. Thirteen GSD type IV patients were liver transplanted because of progressive liver cirrhosis and failure. All but one patient have not had neuromuscular or cardiac complications during follow-up periods for as long as 13 years. Four have died within a week and 5 years after transplantation. Caution should be taken in selecting GSD type IV candidates for liver transplantation because of the variable phenotype, which may include life-limiting extrahepatic manifestations. It remains to be evaluated, whether a genotype-phenotype correlation exists for GSD type IV, which may aid in the decision making. Conclusion Liver transplantation should be considered for patients with glycogen storage disease who have developed liver malignancy or hepatic failure, and for type IV patients with the classical and progressive hepatic form

    Moonlighting Newborn Screening Markers: The Incidental Discovery of a Second-Tier Test for Pompe Disease

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    Purpose: To describe a novel biochemical marker in dried blood spots suitable to improve the specificity of newborn screening for Pompe disease. Methods: The new marker is a ratio calculated between the creatine/creatinine (Cre/Crn) ratio as the numerator and the activity of acid α-glucosidase (GAA) as the denominator. Using Collaborative Laboratory Integrated Reports (CLIR), the new marker was incorporated in a dual scatter plot that can achieve almost complete segregation between Pompe disease and false-positive cases. Results: The (Cre/Crn)/GAA ratio was measured in residual dried blood spots of five Pompe cases and was found to be elevated (range 4.41–13.26; 99%ile of neonatal controls: 1.10). Verification was by analysis of 39 blinded specimens that included 10 controls, 24 samples with a definitive classification (16 Pompe, 8 false positives), and 5 with genotypes of uncertain significance. The CLIR tool showed 100% concordance of classification for the 24 known cases. Of the remaining five cases, three p.V222M homozygotes, a benign variant, were classified by CLIR as false positives; two with genotypes of unknown significance, one likely informative, were categorized as Pompe disease. Conclusion: The CLIR tool inclusive of the new ratio could have prevented at least 12 of 13 (92%) false-positive outcomes

    Portable potentiometric device for determining the antioxidant capacity

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    Received: 25.11.22. Revised: 12.12.22. Accepted: 12.12.22. Available online: 21.12.22.The open microcell and the microfluidic device were developed for the determination of the antioxidants capacity of various objects.The potentiometric method implemented in the devices allows estimating the AOC of model and multicomponent objects.The relative standard deviation of the AOC in the devices did not exceed 10%.At present, the development of portable devices for the express assessment of the content of biologically active objects, such as antioxidants, is one of the relevant technological problems of modern chemistry, medicine, and engineering. The main advantages of such devices are the simplicity and rapidity of analysis, small volumes of analyte, as well as miniaturization of equipment, making it possible to carry out the on-site analysis and, thus, to take a step towards the personalized medicine. The potentiometric method using the K3[Fe(CN)6]/K4[Fe(CN)6] system, which in the laboratory-scale version proved to be the most accurate, reproducible, and express, was the basis for the developed prototypes of portable devices. In this study, two versions of prototypes of the portable device are proposed, namely, the open microcell with the 0.2 ml volume and the microfluidic device with flow control. The correctness of the antioxidant capacity (AOC) determination in both systems was confirmed by comparing the results of the "introduced-found" method on model solutions of antioxidants and their mixtures with the AOC results obtained in a standard laboratory electrochemical cell. The relative standard deviation did not exceed 10%. The AOC of some beverage industry was determined using the microfluidic device. The correlation coefficient of the results, obtained in the microfluidic device and the laboratory cell, was 0.90, which indicates good data convergence and the possibility of using the potentiometric method implemented in the microfluidic device to assess the AOC of multicomponent objects.The research funding from the Ministry of Science and Higher Education of the Russian Federation (Ural Federal University Program of Development within the Priority-2030 Program) is gratefully acknowledged

    2-methylbutyryl-CoA dehydrogenase deficiency associated with autism and mental retardation: a case report

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    <p>Abstract</p> <p>Background</p> <p>2-methylbutyryl-CoA dehydrogenase deficiency or short/branched chain acyl-CoA dehydrogenase deficiency (SBCADD) is caused by a defect in the degradation pathway of the amino acid L-isoleucine.</p> <p>Methods</p> <p>We report a four-year-old mentally retarded Somali boy with autism and a history of seizures, who was found to excrete increased amounts of 2-methylbutyryl glycine in the urine. The SBCAD gene was examined with sequence analysis. His development was assessed with psychometric testing before and after a trial with low protein diet.</p> <p>Results</p> <p>We found homozygosity for A > G changing the +3 position of intron 3 (c.303+3A > G) in the SBCAD gene. Psychometric testing showed moderate mental retardation and behavioral scores within the autistic spectrum. No beneficial effect was detected after 5 months with a low protein diet.</p> <p>Conclusion</p> <p>This mutation was also found in two previously reported cases with SBCADD, both originating from Somalia and Eritrea, indicating that it is relatively prevalent in this population. Autism has not previously been described with mutations in this gene, thus expanding the clinical spectrum of SBCADD.</p
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