High-frequency dielectric anomalies in a highly frustrated square kagome lattice nabokoite family compounds ACu7_7(TeO4_4)(SO4_4)5_5Cl (A=Na, K, Rb, Cs)

Nabokoite family compounds ACu$_7$(TeO$_4$)(SO$_4$)$_5$Cl (A=Na, K, Cs, Rb) are candidates for the experimental realization of highly-frustrated 2D square kagome lattice (SKL). Their magnetic subsystem includes SKL layers decorated by additional copper ions. All members of this family are characterized by quite high Curie-Weiss temperatures ($\sim 80-200$ K), but magnetic ordering was reported only for Na and K compounds at a much lower temperatures below 4 K. We report here results of the study of high-frequency ($\sim 10$ GHz) dielectric properties of this family of compounds. Our study revealed presence of the strong dielectric anomaly both in the real and imaginary parts of high-frequency dielectric permittivity for Na and K compounds approx. 100 and 26 K, correspondingly, presumably related to antiferroelectric ordering. Additionally, much weaker anomalies were observed at approximately 5K indicating possible interplay of magnetic and lattice degrees of freedom. We discuss possible relation between the structure rearrangements accompanying dielectric anomalies and a delayed magnetic ordering in the nabokoite family compounds.Comment: 12 pages, 8 figure

POLYMORPHISM OF GENES RESPONSIBLE FOR THROMBOPHILIA AND THEIR INFLUENCE ON THE DEVELOPMENT OF THROMBOSIS IN CHILDREN

The article is devoted to the prevalence of polymorphism of genes responsible for thrombophilia among children. The study included 52 children with thrombosis and 59 children without thrombosis. Detects mutations factor V Leiden, G20210A prothrombin gene, the C677T mutation in the gene for 5,10-methylenetetrahydrofolate reductase and 4G/5G polymorphism of gene plasminogen activator inhibitor 1. Mutations thrombophilia markers are detected in 38 of 52 (73 %) children with thrombosis, and 36 of 59 (61 %) children without thrombosis (p=0,1). A combination of several mutations in genes had 38 of 69 (55 %) children having different polymorphisms. The highest percentage (86 %) of different combinations of mutations have children with venous thrombosis, wherein the presence of mutations in Factor V (Leiden) mutation and prothrombin gene was isolated, and in all cases with each other or combined with mutation of the MTHFR gene. The most significant in the development of thrombosis are the G20210A mutation in the prothrombin gene mutation and Leiden. An example of clinical thrombosis, the girl with the data mutations

Antibodies raised against a Sunn bug (Eurygaster integriceps Put.) recombinant protease, rGHP3p2, can inhibit gluten‐hydrolyzing activity

Sunn pest or Sunn bug, Eurygaster integriceps Put., salivary gland proteases are responsible for the deterioration of wheat flour quality during dough mixing, resulting from gluten hydrolysis. These proteases are highly heterogeneous and show low sensitivity to most types of proteinaceous inhibitors, meaning that such inhibitors cannot be used to prevent gluten damage. The present study describes the generation of a specific peptide antibody, raised against the active center of the recombinant gluten-hydrolyzing protease (GHP3). The recombinant protein, encoding two repeats of the GHP3 sequence element involved in forming the S4 pocket and binding of substrate at position P4, was designed and expressed in Escherichia coli. The antibodies raised to this recombinant protein showed inhibitory activity against the GHP3 protease. The results indicate that it is possible to design specific antibodies to inhibit wheat-bug gluten-hydrolyzing proteases

Impact of General Anesthesia and Antioxidants on Cognitive, Static and Locomotor Functions During Laparoscopic Cholecystectomy

Aim of the study: to reduce cognitive impairment during laparoscopic cholecystectomy by perioperative administration of drugs with antihypoxic and antioxidant effects under the control of stabilography.   Materials and methods. We studied the effect of general anesthesia and antioxidants on cognitive, static and locomotor functions during laparoscopic cholecystectomy. We studied 90 patients with acute calculous cholecystitis randomized into three experimental groups (n=30, each group). The control group was composed of 24 healthy individuals. Group 1 patients received no antioxidants, group 2 patients received the combination antioxidant drug (sodium fumarate+sodium chloride+potassium chloride+magnesium chloride) in the post-operative period, and group 3 patients received methylethylpyridinol. The patient groups were comparable in sex, age and type of inflammatory and destructive process in the gallbladder. Surgical intervention was performed under endotracheal anesthesia. Premedication with atropine and promedol was given, and anesthesia induction was carried out with propofol, fentanyl and suxamethonium. Sevoflurane, fentanyl andcisatracurium were employed to maintain anesthesia, analgesia and myorelaxation, respectively. The patients were examined before surgery, 24 and 48 hours after surgery. In the groups of patients who received antioxidant therapy, blood sampling for hematological and biochemical examinations was performed 30 min after the administration of antioxidants. Stabilographic studies and MoCA test (Montreal Scale) were performed before antioxidant administration prior to surgery and after surgery, on days 2 and 3.   Results. Neuropsychological testing revealed postoperative cognitive dysfunction on standard therapy which included impaired attention and concentration, executive function, memory, speech, visual constructional skills, abstract thinking, counting, and orientation (21 points on the MoCA scale versus 28–30 points for normal). We found that the pathogenetic factors of cognitive dysfunction included insufficient antioxidant protection, decreased TNF-α and elevated interleukin-18 levels along with an increased level of C-reactive protein in plasma, which manifested as activation of free-radical oxidation processes and reduced antioxidant system and performance of nonspecific resistance. Perioperative use of the combination antioxidant drug and methylethylpyridinol antioxidants reduced the frequency and severity of postoperative cognitive impairment in patients after laparoscopic cholecystectomy.   Conclusion. The most important pathogenetic factors of cognitive dysfunction after laparoscopic cholecystectomy include activation of free-radical oxidation, reduction of antioxidant defense system performance and lack of nonspecific resistance factors. Adding the combination antioxidant drug or methylethylpyridinol to the standard therapy reduces the intensity of radical oxygen species generation, maintains the antioxidant potential, activates production and secretion of nonspecific resistance factors, preventing the development and reducing the severity of cognitive disorders in the perioperative period. Neuropsychological testing and stabilographic examination allow identifying the risk of cognitive disorders in patients after laparoscopic cholecystectomy and provide a rationale for the use of antioxidant therapy for their prevention

О работе семинара «Нелинейная динамика»

В 2011—2012 годах в рамках научно-образовательного центра «Нелинейная динамика» продолжил работу научный семинар, посвященный исследованиям поведения и методам анализа динамических систем. За прошедший учебный год на нем было заслушано более тридцати сообщений по тематике исследований научно-образовательного центра. Ниже представлены тезисы наиболее интересных докладов, прозвучавших на семинаре