Molecular Dynamics Simulations of Weak Detonations

Detonation of a three-dimensional reactive non-isotropic molecular crystal is modeled using molecular dynamics simulations. The detonation process is initiated by an impulse, followed by the creation of a stable fast reactive shock wave. The terminal shock velocity is independent of the initiation conditions. Further analysis shows supersonic propagation decoupled from the dynamics of the decomposed material left behind the shock front. The dependence of the shock velocity on crystal nonlinear compressibility resembles solitary behavior. These properties categorize the phenomena as a weak detonation. The dependence of the detonation wave on microscopic potential parameters was investigated. An increase in detonation velocity with the reaction exothermicity reaching a saturation value is observed. In all other respects the model crystal exhibits typical properties of a molecular crystal.Comment: 38 pages, 20 figures. Submitted to Physical Review

Determination of protein fractions in a sports horse with laryngotracheitis, nonspecifically stimulated with a phytotherapeutic extract (case study

In a sports horse with signs of laryngotracheitis that hardly achieved the training program, a phytotherapeutic extract with immunomodulating properties was administered. Following the administration of the extract, on the second day, the horse showed a remarkable comeback in the sense that it did the normal training without the presence of fatigue and coughing. The horse was clinically examined, blood samples were collected and the extract was inoculated s.c., blood samples were collected at 24 hours, 7 days and 10 days for haematological, biochemical examinations and also for electrophoresis, in order to determin the protein fractions. Significant changes are noted for fractions β1, β2 and γ. In terms of albumin, they are found initially at physiological values, and 24 hours after the inoculation of the extract, very significant decreased throughout the experiment. The most spectacular variations of the protein fractions are those for gamma globulins: initially they are drastically decreased, and 24 hours after the inoculation of the extract, they increased spectacularly, about 3 times, and remain close to this level (in physiological parameters), throughout the experiment. The albumin / globulin ratio is clearly in favor of globulins

Metabolic researches in Țurcana sheep breeding in different pastoral ecosystems

The health of Tsurcana sheep in different pastoral ecosystems is the result of a continuous adaptive metabolic process to macro and microclimate changes, depending on individual factors and breed characteristics (the rustic, indigenous breeds are better adapted). In this paper, the biological study material were two-year old Tsurcana sheep raised in Fagaraș, Rucar, Bacau (Comanești area); exclusively pasture fed; from each region and from each flock we collected blood samples from 5 sheep and we presented the average of the values obtained. We found: hypercholesterolemia in the Tsurcana sheep in all three regions (Fagaras and Rucar with similar values), hyperglobulinemia in Tsurcana sheep from Rucar; increased GOT activity in all the Tsurcana tested, most notably at Rucar; increased GPT activity, the highest value in those from Bacau; the increase in GGT activity, the highest value in Ţurcanele de Bacau. This increased plasma activity is due to hepatic lesions, hyperuraemia (the highest values being registered for the Rucar and Bacău Tsurcana); hypercreatinemia (the highest value in Bacau). A classification, depending on the affected organs: the liver is affected in sheep in Rucar and in Bacau; - the kidney and implicitly the nucleoproteic metabolism is more affected in Bacău and Rucăr sheep; the proteic metabolism in sheep in Rucar, where the highest globulin value were identified; on the other hand the increased globulins play a role in the host immunity and we must not forget that the research was carried out during lactation and the sheep from Rucar graze during summer at Lake Iezer at an altitude of over 1800 m; as for cholesterol, it is increased in sheep in all three regions; so lipid metabolism is disrupted, implicitly liver function. In conclusion: Fagaras Tsurcana have hypercholesterolemia, but excretion and epuration are less affected; correlating the obtained results, it can be argued that routine explorations can sometimes reveal unexpected and isolated transaminase elevations; these increases may be influenced by excess weight, adaptive liver reactions, cardio-circulatory failure etc.; many of these are not clinically investigated

Memory, post-socialism and the media: nostalgia and beyond

While research on the mediation of post-socialist memory has gained momentum in recent years, the field remains fragmented and limited to small-scale case studies, with little attempt to develop a more general reflection on the nature of the processes investigated. Engagement with the wider literature on the mediatisation of memory has been limited as well, with research typically applying established conceptual frameworks rather than using post-socialist materials to generate new theoretical insights. Given the state of the field, this article has a double aim. First, it offers a critical review of the main trends in existing research, focussing on four key issues: the fascination with nostalgic modes of remembering, the dominance of national frames of analysis, the lack of research on the mediation of personal and vernacular remembering, and the privileging of descriptive over explanatory modes of analysis. Second, the article outlines a new agenda for the field, and proposes three main research trajectories. The first pays attention to how mediated memories at local and national levels interact with transnational processes of remembering the Cold War, the second focusses on to the intersections between personal and public modes of mediated remembering, and the last moves the discussion from description to explanation, using comparative approaches to advance explanations of different modes of mediated post-socialist memories

Sodium atoms and clusters on graphite: a density functional study

Sodium atoms and clusters (N<5) on graphite (0001) are studied using density functional theory, pseudopotentials and periodic boundary conditions. A single Na atom is observed to bind at a hollow site 2.45 A above the surface with an adsorption energy of 0.51 eV. The small diffusion barrier of 0.06 eV indicates a flat potential energy surface. Increased Na coverage results in a weak adsorbate-substrate interaction, which is evident in the larger separation from the surface in the cases of Na_3, Na_4, Na_5, and the (2x2) Na overlayer. The binding is weak for Na_2, which has a full valence electron shell. The presence of substrate modifies the structures of Na_3, Na_4, and Na_5 significantly, and both Na_4 and Na_5 are distorted from planarity. The calculated formation energies suggest that clustering of atoms is energetically favorable, and that the open shell clusters (e.g. Na_3 and Na_5) can be more abundant on graphite than in the gas phase. Analysis of the lateral charge density distributions of Na and Na_3 shows a charge transfer of about 0.5 electrons in both cases.Comment: 20 pages, 6 figure

The metabolic status of goats from Târnava Farm, Sibiu County

Târnava farm is located in Sibiu County, 12 km from the town of Mediaș and in 2017 owns 450 goats (740 goats in 2016, 420 in 2015). The farm is based on a reproductive core of different goat breeds: Saanen, French Alpine, Carpathian, cross bred Boer goats, both domestic and acclimated breeds. In establishing the metabolic status of these goats, we took blood samples from 10 2-year-old lactating goats, representing each breed. For each breed we averaged the values obtained and used as reference values the values provided by the equipment manufacturer; the samples were processed in the Laboratory of the Internal Medicine Department of the Faculty of Veterinary Medicine Bucharest. From the research we carried out, what we found metabolically in all the goat breeds on the farm was: normal proteic profile and lipid metabolism, normal enzymatic profile except for an increased alkaline phosphatase; hyperbilirubinemia; creatinemia and normal urea levels. As for the alkaline phosphatase – the orthophosphoric-monoester-phosphohydrolase has three isoenzymes: hepatic, bone, intestinal and during gestation, there is also a placental form. The hepatic alkaline phosphatase, which has major implications in veterinary pathology, plays a role in transport at the biliary and sinusoidal poles of the hepatocyte; in our research we observed that the hepato-biliary alkaline phosphatase is increased and accompanied by hyperbilirubinemia. Small non-specific increases may also occur in heart failure, possibly through intrahepatic biliary duct obstruction, all of which are difficult to follow pathological phenomena in veterinary medicine, so we can discuss about hepato-biliary dysfunction in the goats in this farm. The largest increase in alkaline phosphatase and bilirubin was registered in the Saanen breed, more pronounced in males than in females, followed by the French Alpine breed, while in the Carpathian the growth is moderate. We consider that this is a problem of functional adaptation in these imported breeds, one of the aspects observed during our research, constituting a part of a complex metabolic adaptation syndrome of imported goat breeds

Research on metabolic status in periparturient cows

In the experiment, hematological and blood biochemical parameters were determined in a batch of 5 cows in the last week of gestation (Group 1) and 5 cows in the first week after calving (Group 2). Cows are clinically healthy and come from a farm where the milk production per fed animal is about 30 liters/day, cows being milked 3 times per day. Hematologic parameters were found within physiological limits, but in both groups the monocytes were found to be low, and in group 1, mild lymphopenia was detected. Investigated blood biochemical parameters allowed to assert that in cows in the last week of gestation, bilirubin was found to be significantly increased when recently-bred cows were within normal limits. In both lots, LDH was found to be significantly increased. Metabolic status also determined the protein fractions by means of electrophoresis: 10 samples were analyzed (Group 3 consisting of 5 cows in the last week of gestation and Group 4 consisting of 5 cows in the first week after calving). The values of the protein fractions were within the physiological limits and the Albumin/Globulin Ratio was found within physiological limits in group 3 and lower in group 4, which confirms gamma globulin reactivation immediately after calving

Reversing Blood Flows Act through klf2a to Ensure Normal Valvulogenesis in the Developing Heart

Heart valve anomalies are some of the most common congenital heart defects, yet neither the genetic nor the epigenetic forces guiding heart valve development are well understood. When functioning normally, mature heart valves prevent intracardiac retrograde blood flow; before valves develop, there is considerable regurgitation, resulting in reversing (or oscillatory) flows between the atrium and ventricle. As reversing flows are particularly strong stimuli to endothelial cells in culture, an attractive hypothesis is that heart valves form as a developmental response to retrograde blood flows through the maturing heart. Here, we exploit the relationship between oscillatory flow and heart rate to manipulate the amount of retrograde flow in the atrioventricular (AV) canal before and during valvulogenesis, and find that this leads to arrested valve growth. Using this manipulation, we determined that klf2a is normally expressed in the valve precursors in response to reversing flows, and is dramatically reduced by treatments that decrease such flows. Experimentally knocking down the expression of this shear-responsive gene with morpholine antisense oligonucleotides (MOs) results in dysfunctional valves. Thus, klf2a expression appears to be necessary for normal valve formation. This, together with its dependence on intracardiac hemodynamic forces, makes klf2a expression an early and reliable indicator of proper valve development. Together, these results demonstrate a critical role for reversing flows during valvulogenesis and show how relatively subtle perturbations of normal hemodynamic patterns can lead to both major alterations in gene expression and severe valve dysgenesis

Up-regulation of endothelin type B receptors in the human internal mammary artery in culture is dependent on protein kinase C and mitogen-activated kinase signaling pathways

<p>Abstract</p> <p>Background</p> <p>Up-regulation of vascular endothelin type B (ET_B) receptors is implicated in the pathogenesis of cardiovascular disease. Culture of intact arteries has been shown to induce similar receptor alterations and has therefore been suggested as a suitable method for, <it>ex vivo</it>, in detail delineation of the regulation of endothelin receptors. We hypothesize that mitogen-activated kinases (MAPK) and protein kinase C (PKC) are involved in the regulation of endothelin ET_Breceptors in human internal mammary arteries.</p> <p>Methods</p> <p>Human internal mammary arteries were obtained during coronary artery bypass graft surgery and were studied before and after 24 hours of organ culture, using <it>in vitro </it>pharmacology, real time PCR and Western blot techniques. Sarafotoxin 6c and endothelin-1 were used to examine the endothelin ET_Aand ET_Breceptor effects, respectively. The involvement of PKC and MAPK in the endothelin receptor regulation was examined by culture in the presence of antagonists.</p> <p>Results</p> <p>The endohtelin-1-induced contraction (after endothelin ET_Breceptor desensitization) and the endothelin ET_Areceptor mRNA expression levels were not altered by culture. The sarafotoxin 6c contraction, endothelin ET_Breceptor protein and mRNA expression levels were increased after organ culture. This increase was antagonized by; (1) PKC inhibitors (10 μM bisindolylmaleimide I and 10 μM Ro-32-0432), and (2) inhibitors of the p38, extracellular signal related kinases 1 and 2 (ERK1/2) and C-jun terminal kinase (JNK) MAPK pathways (10 μM SB203580, 10 μM PD98059 and 10 μM SP600125, respectively).</p> <p>Conclusion</p> <p>In conclusion, PKC and MAPK seem to be involved in the up-regulation of endothelin ET_Breceptor expression in human internal mammary arteries. Inhibiting these intracellular signal transduction pathways may provide a future therapeutic target for hindering the development of vascular endothelin ET_Breceptor changes in cardiovascular disease.</p

Piper sarmentosum inhibits ICAM-1 and Nox4 gene expression in oxidative stress-induced human umbilical vein endothelial cells

<p>Abstract</p> <p>Background</p> <p>Aqueous extract of <it>Piper sarmentosum </it>(AEPS) is known to possess antioxidant and anti-atherosclerotic activities but the mechanism responsible for it remains unclear. In early part of atherosclerosis, nuclear factor-kappa B (NF-κB) induces the expression of cellular adhesion molecules such as vascular cell adhesion molecule-1 (VCAM-1), intracellular adhesion molecule-1 (ICAM-1) and E-selectin. NADPH oxidase 4 (Nox4) is the predominant source of superoxide in the endothelial cells whereas superoxide dismutase 1 (SOD1), catalase (CAT) and glutathione peroxidase (GPx) are the antioxidant enzymes responsible for inactivating reactive oxygen species. The present study aimed to investigate the effects of AEPS on the gene expression of NF-κB, VCAM-1, ICAM-1, E-selectin, Nox4, SOD1, CAT and GPx in cultured human umbilical vein endothelial cells (HUVECs).</p> <p>Methods</p> <p>HUVECs were divided into four groups:- control; treatment with 180 μM hydrogen peroxide (H₂O₂); treatment with 150 μg/mL AEPS and concomitant treatment with AEPS and H₂O₂for 24 hours. Total RNA was extracted from all the groups of HUVEC using TRI reagent. Subsequently, qPCR was carried out to determine the mRNA expression of NF-κB, VCAM-1, ICAM-1, E-selectin, Nox4, SOD1, CAT and GPx. The specificity of the reactions was verified using melting curve analysis and agarose gel electrophoresis.</p> <p>Results</p> <p>When stimulated with H₂O₂, HUVECs expressed higher level of ICAM-1 (1.3-fold) and Nox4 (1.2-fold) mRNA expression. However, AEPS treatment led to a reduction in the mRNA expression of ICAM-1 (p < 0.01) and Nox4 (p < 0.05) in the H₂O₂-induced HUVECs. AEPS also upregulated the mRNA expression of SOD1 (p < 0.05), CAT (p < 0.01) and GPx (p < 0.05) in oxidative stress-induced HUVECs. There was no significant change in the mRNA expression of VCAM-1 and E-selectin.</p> <p>Conclusion</p> <p>The expressional suppression of ICAM-1 and Nox4 and induction of antioxidant enzymes might be an important component of the vascular protective effect of AEPS.</p