326 research outputs found
Interaction of hydrogen with impurities in group IVB metals
The energetics of hydrogen bonding with Group IVB metals and the interaction of hydrogen with impurities of 3d-transition and simple metals (Al, Ga, Si, Ge) have been investigated using the projector-augmented-wave (PAW) method within the framework of the density functional theory (DFT). It has been found that the solubility of hydrogen in Ti, Zr, and Hf increases upon their alloying with metals located in the middle of the 3d period. The relationship between the interaction energy of hydrogen with impurities, the lattice distortions, and the electronic structure of the studied systems has been analyzed. It has been shown that impurities do not affect the preferred hydrogen sorption positions in titanium but can change these positions in zirconium and hafnium. The influence of impurities and hydrogen on the electronic structure of metals has been examined. The obtained results have demonstrated that, in the studied metals, the interactions of hydrogen with impurities of 3d-transition and simple metals are determined by different mechanisms: the attraction of hydrogen by transition metal impurities is caused by the size effect, whereas the repulsion of hydrogen by simple metals can be associated with the electronic factors
HEPATORENAL SYNDROME: DIAGNOSTIC AND THERAPEUTIC MANAGEMENT
The practical guidelines on diagnosis and management of hepatorenal syndrome, which could be useful for general medical practitioners, gastroenterologists, and hepatologists, are considered in this paper. Selected recommendations are based on integrated clinical data, international recommendations and results of clinical trials. Beginning from theoretical grounds of hepatorenal syndrome (its definition, diagnostic criteria, and classification), acute kidney injury, and spontaneous bacterial peritonitis, the paper contains diagnostic algorithms (in particular, in ascites, for early revealing hepatorenal syndrome), and main approaches to therapy and prevention. The efficacy criteria and monitoring rules for the terlipressin-based therapy are listed
The effect of ionic composition on acoustic phonon speeds in hybrid perovskites from Brillouin spectroscopy and density functional theory
© The Royal Society of Chemistry 2018. Hybrid organic-inorganic perovskites (HOIPs) have recently emerged as highly promising solution-processable materials for photovoltaic (PV) and other optoelectronic devices. HOIPs represent a broad family of materials with properties highly tuneable by the ions that make up the perovskite structure as well as their multiple combinations. Interestingly, recent high-efficiency PV devices using HOIPs with substantially improved long-term stability have used combinations of different ionic compositions. The structural dynamics of these systems are unique for semiconducting materials and are currently argued to be central to HOIPs stability and charge-transport properties. Here, we studied the impact of ionic composition on phonon speeds of HOIPs from Brillouin spectroscopy experiments and density functional theory calculations for FAPbBr3, MAPbBr3, MAPbCl3, and the mixed halide MAPbBr1.25Cl1.75. Our results show that the acoustic phonon speeds can be strongly modified by ionic composition, which we explain by analysing the lead-halide sublattice in detail. The vibrational properties of HOIPs are therefore tuneable by using targeted ionic compositions in the perovskite structure. This tuning can be rationalized by non-trivial effects, for example, considering the influence of the shape and dipole moment of organic cations. This has an important implications for further improvements in the stability and charge-transport properties of these systems
MATHEMATICAL MODELS PREDICTING LEUKOPENIA AND NEUTROPENIA IN PATIENTS WITH CHRONIC HEPATITIS C IN THE BACKGROUND INTERFERONCONTAINING SCHEMES
Currently in the Russian Federation or chronic hepatitis C (CHC) are still relevant Interferon-based regimens. The purpose of this study is to investigate the influence of baseline characteristics and prognosis of the patient HCV genotype 1 for the development of leukopenia (LP) and neutropenia (NP). We investigated factors such as sex, age, body mass index (BMI), viral load, genotype of Interleukin-28 B (IL-28B), the initial level of leukocytes and neutrophils, alanine aminotransferase (ALT), fibrosis, duration of infection, presence of previous therapy. Absolute values of leukocytes and neutrophils were analyzed on 4, 12, 24, 48 weeks of therapy, and at 4, 12, 24 weeks after antiviral treatment with protease inhibitors (PI) 1 and 2 generation. Prognostic criteria were identified, indicating the possible development of the LP and NP expressed during treatment with interferon: female gender, low initial load, TT-genotype of IL-28B, the initial level of white blood cells and neutrophils below 5,7×109/L and 3,4×109/L, respectively. Mathematical models predicting the onset of LP and NP, formalized in the form of decision trees were also constructed. These models have shown the greatest potential for practical use in view of highest accuracy and reliability
Mathematical Modeling of a Solar Arrays Deploying Process at Ground Tests
This paper focuses on the creating of a mathematical model of a solar array deploying process during ground tests. Lagrange equation was used to obtain the math model. The distinctive feature of this mathematical model is the possibility of taking into account the gravity compensation system influence on the construction in the deploying process and the aerodynamic resistance during ground tests
Inflammatory bowel diseases: Transformation of representations. A review
The global burden of inflammatory bowel disease (IBD) is currently significant and continues to grow due to the increasing prevalence of ulcerative colitis (UC) and Crohn's disease (CD), the increasing costs of diagnosis and treatment, and the high level of disability in patients with this disease. Categories, which leads to the search for risk factors and predictors of aggressive course and extraintestinal manifestations. According to the latest data, the prevalence of UC in Russia is 16.6 per 100 000 population, the annual registered increase is 11.3%; the prevalence of CD is 5.6 per 100 000 population, and the increase is 13.7%. In the Russian population of patients with IBD, the average age of disease onset is 35.3 years for UC and 31.2 years for CD. Moreover, in 89.3% of patients with UC, it took at least 2 years to verify the diagnosis, and in CD, within 2 years from the onset of clinical symptoms, the diagnosis was established in only 72.6% of patients. One of the dominant characteristics of IBD is its multisystem nature, which leads to the development of extraintestinal manifestations (ECM), which can be observed in 50–60% of patients, while up to 25% of patients with IBD have several EMC and the most common variants are joint lesions. A higher frequency of extraintestinal manifestations is observed in CD (up to 45% of patients), in female patients, in smokers and with a longer duration of the disease. To predict clinical remission, the level of fecal calprotectin and CRP, the need for glucocorticosteroids are important, to predict endoscopic remission – the level of fecal calprotectin, and to predict histological remission, an endoscopic Schroeder index value of ≤1 is important. The absolute risk of developing colorectal cancer in IBD remains relatively low, ranging from 1.1 to 5.4% after 20 years of disease. The main risk factors for IBD are total intestinal damage, high inflammatory activity, the stricturing phenotype of CD and the presence of primary sclerosing cholangitis
Pancreatic β-cell protective effect of novel GABA derivatives in rats with type 2 diabetes
Novel GABA derivatives exhibit significant pancreatic β-cell protective effects that may be mediated by enhanced GLP-1, Klotho protein, and Nrf2 transcription factor, and suppressed NF-κB transcription facto
N-acetylcysteine relieves neurologic signs of acute ethanol hangover in rats
Orally administered NAC before acute ethanol intoxication led to a decrease in the severity of neurological deficiency in rats and reduced the amnesic effect of ethanol. This could be due to an improvement of ethanol metabolism and a decrease in the severity of disorders associated with oxidative stress and liver dysfunctio
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