Diffusion and Transport Coefficients in Synthetic Opals

Opals are structures composed of the closed packing of spheres in the size range of nano-to-micro meter. They are sintered to create small necks at the points of contact. We have solved the diffusion problem in such structures. The relation between the diffusion coefficient and the termal and electrical conductivity makes possible to estimate the transport coefficients of opal structures. We estimate this changes as function of the neck size and the mean-free path of the carriers. The theory presented is also applicable to the diffusion problem in other periodic structures.Comment: Submitted to PR

Immunological Remission as a Basis for Dose Reduction of Immunosuppressors in Autoimmune Hepatitis: Results of Monocenter Surveillance Study

Aim of the study: evaluate the role of normalization of humoral immunity to address dose reduction or discontinuation of immunosuppressors in patients with autoimmune hepatitis (AIH).Patients and methods. The data of 47 patients with AIH who received immunosuppressive therapy from April 2001 to August 2023 were analyzed: 10 men (21 %), 37 women (79 %); the average age was 37 (17–66) years. The follow-up period was 10–180 months. Type 1 AIH was diagnosed in 37 patients, type 2 AIH — in 7 patients, seronegative AIH — in 3 patients. The diagnosis was established according to the IAIHG point system. To confirm the diagnosis, a liver biopsy was performed in 17 patients, a histological picture of AIH was detected in all of them. The most used combination was prednisolone and azathioprine — in 25 patients (53.2 %), as well as methylprednisolone and azathioprine — in 8 patients (17 %).Results. In some patients, when the immunosuppressive therapy decreased below the recommended dose, a relapse of the disease developed (Group 1), and in others, remission persisted (Group 2). The concentration of гамма-globulins in patients of Group 1 was 22.5 mg%, in Group 2 — 17.95 mg% (p = 0.00055). IgG level after achieving remission in Group 1 was 1709.7 mg/dL, in Group 2 — 1381.7 mg/dL (p = 0.000001). The terms of ALT normalization in Group 1 were 2.14 months, in Group 2 — 1.47 months (p = 0.037); AST normalization in Group 1 made 2.22 months, in Group 2 — 1.48 months (p = 0.026).Conclusions. Normalization of humoral immunity, as well as rapid normalization of ALT and AST can be considered as markers of maintaining AIH remission when immunosuppressor doses are reduced below standard doses, and in individual patients — the possibility of immunosuppressive therapy withdrawal. This will reduce the risk of adverse events and increase adherence to the therapy. We propose introducing the term “immunological remission” into the clinical lexicon, which, along with biochemical and histological remission, acts as a predictor of persistent remission of AIH

Is Combined Bulevirtide and Pegylated Interferon Therapy for Chronic Hepatitis D Superior over Bulevirtide Monotherapy?

Bulevirtide is a novel antiviral agent approved for suppression of chronic hepatitis D but requiring further research into optimising the treatment scheme.Aim. Comparative assessment of bulevirtide monotherapy versus combined treatment with bulevirtide and pegylat-ed interferon (PEG-IFN) using published trial data.Key points. MYR201 and MYR203 trials expose a higher frequency of HBsAg and HDV RNA extinction, as well as more effective HDV suppression for combined bulevirtide/PEG-IFN therapy compared to bulevirtide monotherapy.Conclusion. Combined bulevirtide/PEG-IFN therapy has particular advantages over bulevirtide monotherapy in patients with chronic hepatitis D. Further research is required to optimise bulevirtide dosage and duration of therapy

Relief and geology of the north polar region of the planet Venus

Description of topographic features is given for the North polar region of the planet Venus. Principal geomorphic types of terrain are characterized as well as their geologic relations. Relative ages of geologic units in Venus North polar region are discussed

Metallic Xenon, Molecular Condensates, and Superconductivity

A possibility of explaining the light absorption observed to occur under pressure-induced xenon metallization as due to the transition to the superconducting state is analyzed. The mechanism of the van der Waals bonding is discussed.Comment: LaTeX 2.09 (RevTeX), 4 pages, 4 PostScript figures included in tex

Determination properties of cast iron used in the installation of anodes

This paper presents the results of determining the cast iron’s properties, which is used in the installation of anodes in the electrolytic production of aluminum. The research methods and applied instruments used for metallographic analysis and chemical composition analysis are described. The results of metallographic analysis of cast iron microstructure “before” and “after” electrolysis are presented. The cast iron’s chemical composition was analyzed by using an X-ray fluorescence spectrometer. The results of experimental melting for testing the casting properties of cast iron for fluidity in a spiral sample are presented

Cause-and-effect relationship between thyroid and liver diseases

Thyroid gland (TG) and the liver are in a complex relationship in both physiological and pathological conditions. Thyroid hormones accelerate metabolic processes, intensify the synthesis of proteins and vitamins, play an important role in the development and differentiation of all cells, including hepatocytes. In addition to the central role in the deiodination of thyroid hormones with the formation of their more active and inactivated forms, the liver also carries out their transport. Dysfunction of TG can lead to changes in liver function, and in liver diseases, abnormalities in the metabolism of thyroid hormones can occur. Most often, liver pathology in diseases of TG is manifested by an increase in the serum activity of enzymes of cytolysis and/or cholestasis. Changes in liver function tests are often observed in patients with thyrotoxicosis. They are based on oxidative stress or cholestasis. The increased activity of osteoblasts in hyperthyroidism leads to an increase in the bone fraction of alkaline phosphatase, which must be taken into account in the differential diagnosis. Hepatotoxicity of thyreostatic drugs is relatively common, ranging from minimal hepatocellular damage to fulminant liver failure. In the case of hypothyroidism, the pathophysiological mechanisms are mainly represented by lipid metabolism disorders leading to fatty degeneration. It should be remembered that severe hypothyroidism can be manifested by hyperammonemia and edematous-ascitic syndrome, requiring differential diagnosis with liver failure. Treatment of liver pathology in TG diseases includes normalization of thyroid status, and in cases of drug hepatitis – temporary withdrawal of a potentially hepatotoxic drug. The data on the association of hypothyroidism and non-alcoholic fatty liver disease in the aspect of developing new therapies are very interesting

Antimatter research in Space

Two of the most compelling issues facing astrophysics and cosmology today are to understand the nature of the dark matter that pervades the universe and to understand the apparent absence of cosmological antimatter. For both issues, sensitive measurements of cosmic-ray antiprotons and positrons, in a wide energy range, are crucial. Many different mechanisms can contribute to antiprotons and positrons production, ranging from conventional reactions up to exotic processes like neutralino annihilation. The open problems are so fundamental (i.e.: is the universe symmetric in matter and antimatter ?) that experiments in this field will probably be of the greatest interest in the next years. Here we will summarize the present situation, showing the different hypothesis and models and the experimental measurements needed to lead to a more established scenario.Comment: 10 pages, 7 figures, Invited talk at the 18th European Cosmic Ray Symposium, Moscow, July 2002, submitted to Journal of Physics

Association of insulin resistance and non-alcoholic fatty liver disease

BACKGROUND: The number of patients with chronic metabolic disorders such as obesity, type 2 diabetes mellitus (T2D) and non-alcoholic fatty liver disease (NAFLD) is growing at an alarming rate worldwide in both developed and developing countries. In the world, the prevalence of NAFLD is approaching 25%. Among patients with T2D, 70–80% are diagnosed with NAFLD. Insulin resistance (IR) is recognized as one of the main pathogenetic factors in the development of the most common chronic liver disease — NAFLD.AIM: Our search work was aimed at determining the contribution of the degree of IR to the progression of NAFLD; compare the gold standard for the determination of IR (clamp) and the mathematical model (HOMA-IR).METHODS: An observational one-stage open comparative study was conducted on the basis of the case-control principle. The objects of the study were overweight and obese patients who had not previously been diagnosed carbohydrate metabolism disorders, without secondary causes of fat accumulation in the liver. During the examination, clinical and laboratory studies were carried out, IR indices (M-index, HOMA-IR index) were obtained, a diagnosis of carbohydrate metabolism disturbance (or its absence) was made, a liver biopsy was made, morphological and clinical diagnoses were made.RESULTS: The analysis included information about 60 patients, they are divided into 3 groups: without NAFLD (7 people), with steatosis (18 people), with non-alcoholic steatohepatitis (NASH) (35 people), groups are comparable by age, gender, and body mass index (BMI), glycated hemoglobin. When assessing the degree of IR using the hyperinsulinemic euglycemic clamp test, 19 showed a severe degree of IR, 28 had a moderate degree, 8 had a mild degree, and 5 had no IR. In the three studied groups, the median IR corresponded to an average degree and did not significantly differ. When comparing the gold standard for determining IR and the mathematical model (HOMA-IR) in the studied groups, an negative significant correlation was revealed (p = 0,0001).CONCLUSIONS: In the course of our study, no correlation was found between the degree of IR and the severity of NAFLD. This result allows us to think about other pathogenetic factors that affect the progression of NAFLD