110 research outputs found
Free Energy of an SU(2) Model of (2+1)-dimensional QCD in the Constant Condensate Background
Gluon and quark contributions to the thermodynamic potential (free energy) of
a (2+1)-dimensional QCD model at finite temperature in the background of a
constant homogeneous chromomagnetic field H combined with A_0 condensate are
calculated. The role of the tachyonic mode in the gluon energy spectrum is
discussed. A possibility of the free energy global minimum generation at
nonzero values of H and A_0 condensates is investigated.Comment: LaTeX 2e, 14 pages, 6 eps figures, some miscalculations were
correcte
Form factors for decay in a model constrained by chiral symmetry and quark model
The form factors for the transition are evaluated in the entire
momentum transfer range by using the constraints obtained in the framework
combining the heavy quark expansion and chiral symmetry for light quarks and
the quark model. In particular, we calculate the valence quark contributions
and show that it together with the equal time commutator contribution simulate
a B-meson pole q^2-dependence of form factors in addition to the usual vector
meson B^{*}-pole diagram for in the above framework. We
discuss the predictions in our model, which provide an estimate of |V_{ub}|^2.Comment: 7 pages, Revtex, 5 figure, fig 3 is replaced and some text is adde
Classical and quantized aspects of dynamics in five dimensional relativity
A null path in 5D can appear as a timelike path in 4D, and for a certain
gauge in 5D the motion of a massive particle in 4D obeys the usual quantization
rule with an uncertainty-type relation. Generalizations of this result are
discussed in regard to induced-matter and membrane theory.Comment: 26 pages, in press in Class. Quant. Gra
Role of Vector Mesons in High-Q^2 Lepton-Nucleon Scattering
The possible role played by vector mesons in inclusive deep inelastic
lepton-nucleon scattering is investigated. In the context of the convolution
model, we calculate self-consistently the scaling contribution to the nucleon
structure function using the formalism of time-ordered perturbation theory in
the infinite momentum frame. Our results indicate potentially significant
effects only when the vector meson---nucleon form factor is very hard.
Agreement with the experimental antiquark distributions, however, requires
relatively soft form factors for the , and vertices.Comment: 22 pages, 9 figures (available upon request); accepted for
publication in Phys.Rev.D, ADP-92-197/T12
The Pioneer anomaly in the context of the braneworld scenario
We examine the Pioneer anomaly - a reported anomalous acceleration affecting
the Pioneer 10/11, Galileo and Ulysses spacecrafts - in the context of a
braneworld scenario. We show that effects due to the radion field cannot
account for the anomaly, but that a scalar field with an appropriate potential
is able to explain the phenomena. Implications and features of our solution are
analyzed.Comment: Final version to appear at Classical & Quantum Gravity. Plainlatex 19
page
Application of high-volume continuous venovenous hemofiltration in complex therapy of severe thermal injury at children
Purpose: assessment of efficiency of application of high-volume continuous venovenous hemofiltration at children with severe thermal injury in the period of burn shock. Materials and methods: there were studied 23 patients with severe thermal injury. High-volume continuous venovenous hemofiltration was entered in the list of intensive care for 12 children during the first 72 hours from the moment of burn. High-volume continuous veno-venous hemofiltration was carried out on the apparatus Prisma Flex with use of sorption membrane hemocartridge AN 69 Prisma Flex ST 60 S e t.. This method was not used at the group of comparison which consist of 11 children. Index of central hemodynamics, biome-chanics of respiration, transport of 02, acid-base balance of blood were studied.Resume: there were determined that application of this method at children with severe thermal injury prevent progression of syndrom of multiple organ failure, decrease number of involved systems, promote improvement results of therapy.Цель работы: оценить эффективность применения продленной гемофильтрации у детей с тяжелой термической травмой в периоде ожогового шока для профилактики полиорганной недостаточности. Материалы и метод: в исследование вошло 23 пациента с тяжёлой термической травмой. 12-ти детям в первые 72 часа с момента ожога в протокол интенсивной терапии была включена продлённая вено-венозная гемофильтрация, которая проводилась на аппарате Prisma Flex, с использованием сорбционно-мембранного гемокартриджа AN 69 Prisma Flex ST 60 Set. Группа сравнения — 11 детей, которым данная методика не применялась. Изучены показатели центральной гемодинамики, биомеханики дыхания, транспорта 02, кислотно-основного состояния крови. Вывод: установлено, что применение данного метода у детей с тяжелой термической травмой в период ожогового шока предотвращает прогрессирование СПОИ, уменьшает число вовлекаемых систем, способствует улучшению результатов лечения
Solulin reduces infarct volume and regulates gene-expression in transient middle cerebral artery occlusion in rats
<p>Abstract</p> <p>Background</p> <p>Thrombolysis after acute ischemic stroke has only proven to be beneficial in a subset of patients. The soluble recombinant analogue of human thrombomodulin, Solulin, was studied in an <it>in vivo </it>rat model of acute ischemic stroke.</p> <p>Methods</p> <p>Male SD rats were subjected to 2 hrs of transient middle cerebral artery occlusion (tMCAO). Rats treated with Solulin intravenously shortly before reperfusion were compared to rats receiving normal saline i.v. with respect to infarct volumes, neurological deficits and mortality. Gene expression of IL-6, IL-1β, TNF-α, MMP-9, CD11B and GFAP were semiquantitatively analyzed by rtPCR of the penumbra.</p> <p>Results</p> <p>24 hrs after reperfusion, rats were neurologically tested, euthanized and infarct volumes determined. Solulin significantly reduced mean total (p = 0.001), cortical (p = 0.002), and basal ganglia (p = 0.036) infarct volumes. Hippocampal infarct volumes (p = 0.191) were not significantly affected. Solulin significantly downregulated the expression of IL-1β (79%; p < 0.001), TNF-α (59%; p = 0.001), IL-6 (47%; p = 0.04), and CD11B (49%; p = 0.001) in the infarcted cortex compared to controls.</p> <p>Conclusions</p> <p>Solulin reduced mean total, cortical and basal ganglia infarct volumes and regulated a subset of cytokines and proteases after tMCAO suggesting the potency of this compound for therapeutic interventions.</p
Probing exotic phenomena at the interface of nuclear and particle physics with the electric dipole moments of diamagnetic atoms: A unique window to hadronic and semi-leptonic CP violation
The current status of electric dipole moments of diamagnetic atoms which
involves the synergy between atomic experiments and three different theoretical
areas -- particle, nuclear and atomic is reviewed. Various models of particle
physics that predict CP violation, which is necessary for the existence of such
electric dipole moments, are presented. These include the standard model of
particle physics and various extensions of it. Effective hadron level combined
charge conjugation (C) and parity (P) symmetry violating interactions are
derived taking into consideration different ways in which a nucleon interacts
with other nucleons as well as with electrons. Nuclear structure calculations
of the CP-odd nuclear Schiff moment are discussed using the shell model and
other theoretical approaches. Results of the calculations of atomic electric
dipole moments due to the interaction of the nuclear Schiff moment with the
electrons and the P and time-reversal (T) symmetry violating
tensor-pseudotensor electron-nucleus are elucidated using different
relativistic many-body theories. The principles of the measurement of the
electric dipole moments of diamagnetic atoms are outlined. Upper limits for the
nuclear Schiff moment and tensor-pseudotensor coupling constant are obtained
combining the results of atomic experiments and relativistic many-body
theories. The coefficients for the different sources of CP violation have been
estimated at the elementary particle level for all the diamagnetic atoms of
current experimental interest and their implications for physics beyond the
standard model is discussed. Possible improvements of the current results of
the measurements as well as quantum chromodynamics, nuclear and atomic
calculations are suggested.Comment: 46 pages, 19 tables and 16 figures. A review article accepted for
EPJ
Mutant Prourokinase with Adjunctive C1-Inhibitor Is an Effective and Safer Alternative to tPA in Rat Stroke
A single-site mutant (M5) of native urokinase plasminogen activator (prouPA) induces effective thrombolysis in dogs with venous or arterial thrombosis with a reduction in bleeding complications compared to tPA. This effect, related to inhibition of two-chain M5 (tcM5) by plasma C1-inhibitor (C1I), thereby preventing non-specific plasmin generation, was augmented by the addition of exogenous C1I to plasma in vitro. In the present study, tPA, M5 or placebo +/− C1I were administered in two rat stroke models. In Part-I, permanent MCA occlusion was used to evaluate intracranial hemorrhage (ICH) by the thrombolytic regimens. In Part II, thromboembolic occlusion was used with thrombolysis administered 2 h later. Infarct and edema volumes, and ICH were determined at 24 h, and neuroscore pre (2 h) and post (24 h) treatment. In Part I, fatal ICH occurred in 57% of tPA and 75% of M5 rats. Adjunctive C1I reduced this to 25% and 17% respectively. Similarly, semiquantitation of ICH by neuropathological examination showed significantly less ICH in rats given adjunctive C1I compared with tPA or M5 alone. In Part-II, tPA, M5, and M5+C1I induced comparable ischemic volume reductions (>55%) compared with the saline or C1I controls, indicating the three treatments had a similar fibrinolytic effect. ICH was seen in 40% of tPA and 50% of M5 rats, with 1 death in the latter. Only 17% of the M5+C1I rats showed ICH, and the bleeding score in this group was significantly less than that in either the tPA or M5 group. The M5+C1I group had the best Benefit Index, calculated by dividing percent brain salvaged by the ICH visual score in each group. In conclusion, adjunctive C1I inhibited bleeding by M5, induced significant neuroscore improvement and had the best Benefit Index. The C1I did not compromise fibrinolysis by M5 in contrast with tPA, consistent with previous in vitro findings
In vivo PET imaging of the neuroinflammatory response in rat spinal cord injury using the TSPO tracer [F-18]GE-180 and effect of docosahexaenoic acid
Centre for Trauma Sciences, funded by the Barts & The London Charity, GE Healthcare Ltd, the
Experimental Medicine Awards from the Blizard Institute and the Imaging Centre at the Barts Cancer Institute
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