Isothermal-isobaric molecular dynamics using stochastic velocity rescaling

The authors present a new molecular dynamics algorithm for sampling the isothermal-isobaric ensemble. In this approach the velocities of all particles and volume degrees of freedom are rescaled by a properly chosen random factor. The technical aspects concerning the derivation of the integration scheme and the conservation laws are discussed in detail. The efficiency of the barostat is examined in Lennard-Jones solid and liquid near the triple point and compared with the deterministic Nos\'{e}-Hoover and the stochastic Langevin methods. In particular, the dependence of the sampling efficiency on the choice of the thermostat and barostat relaxation times is systematically analyzed.Comment: Accepted for publication on Journal of Chemical Physic

ВПЛИВ ЕКЗО- ТА ЕНДОГЕННИХ ЧИННИКІВ НА МОРФОЛОГІЮ ПІДШЛУНКОВОЇ ЗАЛОЗИ: (ОГЛЯД ЛІТЕРАТУРИ)

Summary. The article is devoted to the study and detailed analysis of articles and scientific literature on the morphofunctional features of pancreatic remodeling with various effects on the body. The pancreas, along with other glands involved in the regulation of body functions, so the violation of its activities under the influence of various factors is a topical issue. The aim of the study – to learn and analyze the current data of scientists on the influence of various factors on the reorganization of the pancreas and to identify new promising morphological views on the study of the organ. Materials and Methods. The material for the article was scientific publications in recent years on the influence of various factors on the morphological features of the pancreas. Results. The article considers the literature on the effects on the pancreas of salts of heavy metals, drugs and toxic substances, alcohol, smoking, starvation, obesity, gravity, oxygen starvation, hyperoxygenation, hypothermia, dehydration, iodine deficiency, drugs, and viral infections. under the action of electric current. However, a small number of scientific sources are devoted to the influence of thermal factors on the condition of the pancreas. Conclusions. According to the analysis of literature sources to date, the influence of a significant number of external and internal factors on the pancreas has been stu­died. However, the effect of thermal skin burns on the morphofunctional state of the gland in modern scientific articles is almost non-existent, so this problem requires further research.Резюме. Стаття присвячена вивченню та детальному аналізу статей та наукової літератури щодо морфофункціональних особливостей ремоделювання підшлункової залози при різноманітних впливах на організм. Підшлункова залоза разом з іншими залозами беруть участь у регуляції функцій організму, тому порушення її діяльності під впливом різноманітних чинників є актуальною темою. Мета дослідження – вивчити і проаналізувати сучасні дані науковців щодо впливу різноманітних чинників на реорганізацію підшлункової залози та виокремити нові перспективні морфологічні погляди на дослідження органа. Матеріали і методи. Матеріалом для статті були наукові публікації за останні роки, що стосувалися впливу різноманітних чинників на морфологічні особливості підшлункової залози. Результати. У дослідженні розглянуто літературні дані впливу на підшлункову залозу солей важких металів, наркотичних і токсичних речовин, алкоголю, тютюнокуріння, голодування, ожиріння, гравітаційних навантажень, кисневого голодування, гіпероксигенації, гіпотермії, дегідратації, недостатньої кількості йоду, лікарських препаратів, вірусних інфекцій, а також при дії електричного струму. Проте невелика кількість наукових джерел присвячена впливу термічного фактора на стан підшлункової залози. Висновки. Згідно з аналізом літературних джерел, вивчено вплив значної кількості зовнішніх та внутрішніх чинників на підшлункову залозу. Проте вплив термічних опіків шкіри на морфофункціональний стан залози у сучасних наукових статтях практично не зустрічається, тому дана проблема потребує подальших досліджень

Influence of CSP 310 and CSP 310-like proteins from cereals on mitochondrial energetic activity and lipid peroxidation in vitro and in vivo

BACKGROUND: The development of chilling and freezing injury symptoms in plants is known to frequently coincide with peroxidation of free fatty acids. Mitochondria are one of the major sources of reactive oxygen species during cold stress. Recently it has been suggested that uncoupling of oxidation and phosphorylation in mitochondria during oxidative stress can decrease ROS formation by mitochondrial respiratory chain generation. At the same time, it is known that plant uncoupling mitochondrial protein (PUMP) and other UCP-like proteins are not the only uncoupling system in plant mitochondria. All plants have cyanide-resistant oxidase (AOX) whose activation causes an uncoupling of respiration and oxidative phosphorylation. Recently it has been found that in cereals, cold stress protein CSP 310 exists, and that this causes uncoupling of oxidation and phosphorylation in mitochondria. RESULTS: We studied the effects of CSP 310-like native cytoplasmic proteins from a number of cereal species (winter rye, winter wheat, Elymus and maize) on the energetic activity of winter wheat mitochondria. This showed that only CSP 310 (cold shock protein with molecular weight 310 kD) caused a significant increase of non-phosphorylative respiration. CSP 310-like proteins of other cereals studied did not have any significant influence on mitochondrial energetic activity. It was found that among CSP 310-like proteins only CSP 310 had prooxidant activity. At the same time, Elymus CSP 310-like proteins have antioxidant activity. The study of an influence of infiltration by different plant uncoupling system activators (pyruvate, which activates AOX, and linoleic acid which is a substrate and activator for PUMP and CSP 310) showed that all of these decreased lipid peroxidation during cold stress. CONCLUSIONS: Different influence of CSP 310-like proteins on mitochondrial energetic activity and lipid peroxidation presumably depend on the various subunit combinations in their composition. All the plant cell systems that caused an uncoupling of oxidation and phosphorylation in plant mitochondria can participate in plant defence from oxidative damage during cold stress

Charging Induced Emission of Neutral Atoms from NaCl Nanocube Corners

Detachment of neutral cations/anions from solid alkali halides can in principle be provoked by donating/subtracting electrons to the surface of alkali halide crystals, but generally constitutes a very endothermic process. However, the amount of energy required for emission is smaller for atoms located in less favorable positions, such as surface steps and kinks. For a corner ion in an alkali halide cube the binding is the weakest, so it should be easier to remove that atom, once it is neutralized. We carried out first principles density functional calculations and simulations of neutral and charged NaCl nanocubes, to establish the energetics of extraction of neutralized corner ions. Following hole donation (electron removal) we find that detachment of neutral Cl corner atoms will require a limited energy of about 0.8 eV. Conversely, following the donation of an excess electron to the cube, a neutral Na atom is extractable from the corner at the lower cost of about 0.6 eV. Since the cube electron affinity level (close to that a NaCl(100) surface state, which we also determine) is estimated to lie about 1.8 eV below vacuum, the overall energy balance upon donation to the nanocube of a zero energy electron from vacuum will be exothermic. The atomic and electronic structure of the NaCl(100) surface, and of the nanocube Na and Cl corner vacancies are obtained and analyzed as a byproduct.Comment: 16 pages, 2 table, 7 figure

Gadolinium-based hybrid ultra-low-background material for protecting the darkside20k dark matter detector from background neutrons

A laboratory technique was developed for obtaining an ultra-low-background hybrid material based on organic glass - polymethyl methacrylate (PMMA). 157Gd nuclei are used as an efficient absorber of thermal neutrons in the hybrid material. A uniform distribution of gadolinium in the PMMAmatrix is achieved by introducing he gadolinium in the form of a coordination compound -gadolinium acetylacetonate- into the hybrid materia

Influence of post-post processing technology and laser radiation parameters on the optical breakdown threshold of a ZnGeP2 single crystal

The aim of this work is to determine the influence of the parameters of post-growth technological operations and experimental conditions on the threshold of optical breakdown of the surface of ZGP crystals under the action of laser radiation at a wavelength of 2091 nm

Relationship between serologic profile (ANCA type) and clinical features of renal involvement in ANCA-associated vasculitides

Objective. To compare the frequency, clinical features and outcomes of renal involvement in ANCA-associated vasculitides (AAV) in patients with antibodies against proteinase-3 (pr3-ANCA) and myeloperoxidase (MPO-ANCA). Materials and methods. In our retrospective study we enrolled 264 patients, 94 males and 170 females, median age 53 [36; 62] years. Among them 157 were pr3-ANCA positive and 107 were MPO-ANCA positive. AAV was diagnosed according to ACR criteria and Chapel Hill consensus conference definition (2012). Median follow up was 44 [18; 93] months. We assessed baseline BVAS and VDI by the end of the follow up. Serum creatinine (sCr), estimated glomerular filtration rate (eGFR), hematuria and daily proteinuria were estimated. Diagnosis and stage of chronic kidney disease (CKD) and acute kidney injury (AKI) were established according to KDIGO guidelines (2012) and Scientific Society of Russian Nephrologists (2016). Results. Renal involvement was present in 181 (68.6%) patients, and its frequency was similar in pr3-ANCA and MPO-ANCA subgroups. Patients with MPO-ANCA developed rapidly progressive glomerulonephritis and hypertension significantly more often than patients with pr3-ANCA: 50.7% vs 35.6% (p=0.049) and 46.1% vs 29.8% (p=0.029) respectively. At disease onset, median sCr was significantly higher and eGFR was significantly lower in patients with MPO-ANCA (

Monte Carlo Methods for Estimating Interfacial Free Energies and Line Tensions

Excess contributions to the free energy due to interfaces occur for many problems encountered in the statistical physics of condensed matter when coexistence between different phases is possible (e.g. wetting phenomena, nucleation, crystal growth, etc.). This article reviews two methods to estimate both interfacial free energies and line tensions by Monte Carlo simulations of simple models, (e.g. the Ising model, a symmetrical binary Lennard-Jones fluid exhibiting a miscibility gap, and a simple Lennard-Jones fluid). One method is based on thermodynamic integration. This method is useful to study flat and inclined interfaces for Ising lattices, allowing also the estimation of line tensions of three-phase contact lines, when the interfaces meet walls (where "surface fields" may act). A generalization to off-lattice systems is described as well. The second method is based on the sampling of the order parameter distribution of the system throughout the two-phase coexistence region of the model. Both the interface free energies of flat interfaces and of (spherical or cylindrical) droplets (or bubbles) can be estimated, including also systems with walls, where sphere-cap shaped wall-attached droplets occur. The curvature-dependence of the interfacial free energy is discussed, and estimates for the line tensions are compared to results from the thermodynamic integration method. Basic limitations of all these methods are critically discussed, and an outlook on other approaches is given