EVOLUTION OF THE CARBON NANOTUBE BUNDLE STRUCTURE UNDER BIAXIAL AND SHEAR STRAINS

Close packed carbon nanotube bundles are materials with highly deformable elements, for which unusual deformation mechanisms are expected. Structural evolution of the zigzag carbon nanotube bundle subjected to biaxial lateral compression with the subsequent shear straining is studied under plane strain conditions using the chain model with a reduced number of degrees of freedom. Biaxial compression results in bending of carbon nanotubes walls and formation of the characteristic pattern, when nanotube cross-sections are inclined in the opposite directions alternatively in the parallel close-packed rows. Subsequent shearing up to a certain shear strain leads to an appearance of shear bands and vortex-like displacements. Stress components and potential energy as the functions of shear strain for different values of the biaxial volumetric strain are analyzed in detail. A new mechanism of carbon nanotube bundle shear deformation through cooperative, vortex-like displacements of nanotube cross sections is reported

Mathematical model of the starter system for a three-stage synchronous generator with a damping cage

В данной статье рассматривается математическая модель стартерной системы для газотурбинных двигателей. Модель исследуемого трехкаскадного синхронного генератора была построена в системе d-q-координат. Полученная модель позволяет сконфигурировать параметры машины в широком диапазоне, а также получить информацию о токах и напряжениях основных электрических узлов машины. Математическое моделирование показало эффективность полученной модели и адекватность предложенного алгоритма электростартерного запуска синхронной машины.This paper, considers a mathematical model the starter system for gas turbine engines. Model of the investigated three-stage synchronous generator has been built in the dq-coordinates. The obtained model allows one to configure the machine parameters in a wide range, as well as receive information about currents and voltages major electrical components of the machine. Mathematical modeling shown efficiency of the resulting model and adequacy of the proposed algorithms electric starter mode synchronous machine

Assessment of senile asthenia syndrome using the Frailty and Edmonton frail scales in elderly and senile patients who underwent emergency abdominal surgery

The aim of the work was to compare the effectiveness of the assessment of senile asthenia syndrome using the Frailty and Edmonton Frail scales in elderly and senile patients undergoing emergency abdominal surgery. Materials and methods. The study included 80 patients aged 60 to 89 years with a diagnosis of acute calculous cholecystitis. A correlation was determined between asthenia and the severity of the patient’s condition according to the P-POSSUM scale, the peak value of the increase in the risk of postoperative complications and mortality occurs in patients with a sum of points >32, p = 0.012. The syndrome of senile asthenia using the Edmonton Frail scale was detected in 30 (37.5 %) patients, according to the Frailty scale – 32 (40.0 %), U = 3120.0, p = 0.7862. Results. The main advantage of the Edmonton Frail scale is the examination time of 22 ± 3 min, while with the Frailty scale 360 ± 22 min (U = 24.5, p < 0.0001). Based on the assessment of the severity of the condition using the P-POSSUM scale, we determined a direct correlation of average strength between the presence of asthenia and the number of points: Edmonton Frail subgroup A – rs = 0.81, p = 0.000001. The same results, respectively, on the Frailty scale – rs = 0.78, p = 0.000004. The frequency of complications increases significantly in the category of patients with asthenia, which is confirmed by both the Edmonton Frail scale – 23.3 % (U = 605.0, p = 0.0087), and the Frailty scale – 21.9 % (U = 632.0, p = 0.0150). Conclusions. The frequency of detection of senile asthenia syndrome using the Edmonton Frail and Frailty scale in patients was equivalent (U = 3120.0, p = 0.7862). The Edmonton Frail scale is more convenient to use in urgent situations, and the mean time to diagnose asthenia using it was 22 ± 3 min, while the complete diagnosis using the Frailty scale took 360 ± 22 min (U = 24.5, p < 0.0001). A significant increase in the frequency of postoperative complications was determined in the category of patients with asthenia, confirmed both by the Edmonton Frail scale – 23.3 % (U = 605.0, p = 0.0087), and by the Frailty scale – 21.9 % (U = 632.0, p = 0.0150)

Pharmacological sequestration of mitochondrial calcium uptake protects against dementia and β-amyloid neurotoxicity

All forms of dementia including Alzheimer's disease are currently incurable. Mitochondrial dysfunction and calcium alterations are shown to be involved in the mechanism of neurodegeneration in Alzheimer's disease. Previously we have described the ability of compound Tg-2112x to protect neurons via sequestration of mitochondrial calcium uptake and we suggest that it can also be protective against neurodegeneration and development of dementia. Using primary co-culture neurons and astrocytes we studied the effect of Tg-2112x and its derivative Tg-2113x on β-amyloid-induced changes in calcium signal, mitochondrial membrane potential, mitochondrial calcium, and cell death. We have found that both compounds had no effect on β-amyloid or acetylcholine-induced calcium changes in the cytosol although Tg2113x, but not Tg2112x reduced glutamate-induced calcium signal. Both compounds were able to reduce mitochondrial calcium uptake and protected cells against β-amyloid-induced mitochondrial depolarization and cell death. Behavioral effects of Tg-2113x on learning and memory in fear conditioning were also studied in 3 mouse models of neurodegeneration: aged (16-month-old) C57Bl/6j mice, scopolamine-induced amnesia (3-month-old mice), and 9-month-old 5xFAD mice. It was found that Tg-2113x prevented age-, scopolamine- and cerebral amyloidosis-induced decrease in fear conditioning. In addition, Tg-2113x restored fear extinction of aged mice. Thus, reduction of the mitochondrial calcium uptake protects neurons and astrocytes against β-amyloid-induced cell death and contributes to protection against dementia of different ethology. These compounds could be used as background for the developing of a novel generation of disease-modifying neuroprotective agents

Novel potent pyridoxine-based inhibitors of AChE and BChE, structural analogs of pyridostigmine, with improved in vivo safety profile

© 2016 Elsevier LtdWe report a novel class of carbamate-type ChE inhibitors, structural analogs of pyridostigmine. A small library of congeneric pyridoxine-based compounds was designed, synthesized and evaluated for AChE and BChE enzymes inhibition in vitro. The most active compounds have potent enzyme inhibiting activity with IC50 values in the range of 0.46–2.1 μM (for AChE) and 0.59–8.1 μM (for BChE), with moderate selectivity for AChE comparable with that of pyridostigmine and neostigmine. Acute toxicity studies using mice models demonstrated excellent safety profile of the obtained compounds with LD50 in the range of 22–326 mg/kg, while pyridostigmine and neostigmine are much more toxic (LD50 3.3 and 0.51 mg/kg, respectively). The obtained results pave the way to design of novel potent and safe cholinesterase inhibitors for symptomatic treatment of neuromuscular disorders

Hormonal parameters and embryological outcomes of in vitro fertilisation/intra cytoplasmic sperm injection cycles in women using dydrogesterone for the prevention of premature luteinizing hormone surge during ovarian stimulation

Aim. To evaluate the hormonal parameters and embryological outcomes of an ovarian stimulation protocol using dydrogesterone to prevent the premature LH surge in IVF/ICSI programmes. Materials and methods. A prospective study randomised, including 79 women with normal ovarian reserve undergoing ovarian stimulation for IVF/ICSI with recombinant FSH (rFSH) from Day 2 or 3 of the menstrual cycle. To prevent the premature LH surge, participants in Group 1 (n=38) received oral dydrogesterone 20 mg/day from the start of ovarian stimulation until the day of ovulation trigger administration. Participants in Group 2 (n=41) received a GnRH antagonist. We evaluated the starting and total dose of gonadotropins, duration of stimulation, serum levels of LH, oestradiol and progesterone on Day 1 and 6 of stimulation and the day of trigger administration, number of retrieved and mature oocytes, fertilization rate, and the number of blastocysts and cryopreserved embryos. Results. There were no significant differences in most hormonal parameters, characteristics of the ovarian stimulation and embryological outcomes between the two groups. Serum levels of progesterone in the dydrogesterone arm were higher than in the GnRH antagonist arm (2.3 nmol/l [2.03.4] vs 1.5 [1.02.4] nmol/l; p=0.026), but without any impact on the embryological outcomes. Conclusion. Prevention of premature LH surge in ovarian stimulation cycles using oral dydrogesterone may represent a convenient alternative to the conventional use of GnRH antagonists, reducing the number of required injections and potentially increasing the convenience in patients who are not planning a fresh embryo transfer

APPLICATION OF ARTIFICIAL INTELLIGENCE METHODS IN SOLVING THE PROBLEM OF COMMUNICATION OF PEOPLE WITH SPEECH DEFECTS

Проведена аналитика по видам и количеству заболеваемости речевого аппарата в России и мире, найдены и приведены способы и методы решения проблем людей с дефектами речи, в частности проблемы коммуникации, средствами искусственного интеллекта, показаны примеры решения зарубежными компаниями.An analysis was carried out on the types and number of morbidity of the speech apparatus in Russia and the world, methods and methods of solving the problem of communication of people with speech defects by means of arificial intelligence were found and presented, examples of solutions by foreign companies were shown