661 research outputs found
The gas phase cyclization of deprotonated N-aryl-2-cyano-2-diazoacetamides
The document attached has been archived with permission from the publisher.1-Aryl-4-cyano-5-hydroxy-1,2,3-triazoles can be obtained in solution by base-catalysed cyclization of N-aryl-2-cyano-2-diazoacetamides. A similar reaction was shown to take place under conditions of negative ion chemical ionization in the ion source of a mass spectrometer. High resolution mass spectrometry, tandem mass spectrometry, charge reversal spectra, synthesis of the ions with known structures and quantum chemical calculations were used to prove the latter statement. The fact of the observed cyclization demonstrates once again the ability of mass spectrometry to study the gas phase chemical reactions that take place in solution.Vladislav V. Lobodin, Yuriy Yu. Morzherin, Tom Blumenthal, Daniel Bilusich, Vladimir V. Ovcharenko, John H. Bowie, and Albert T. Lebede
Synthesis of nitroxyl radical by direct nucleophilic functionalization of a C-H bond in the azadiene systems
Cyclic dinitrones underwent nucleophilic substitution of the hydrogen atom in the reaction with a paramagnetic carbanion, the lithium derivative of 4,4,5,5-tetramethyl-4,5-dihydro-1H-imidazol-1-oxyl 3-oxide, to give polyfunctional nitronyl nitroxyls. © 2012 Springer Science+Business Media New York
Observation and Control of Laser-Enabled Auger Decay
Single photon laser enabled Auger decay (spLEAD) has been redicted
theoretically [Phys. Rev. Lett. 111, 083004 (2013)] and here we report its
first experimental observation in neon. Using coherent, bichromatic
free-electron laser pulses, we have detected the process and coherently
controlled the angular distribution of the emitted electrons by varying the
phase difference between the two laser fields. Since spLEAD is highly sensitive
to electron correlation, this is a promising method for probing both
correlation and ultrafast hole migration in more complex systems.Comment: 5 pages, 3 figure
Geometry and symmetries of multi-particle systems
The quantum dynamical evolution of atomic and molecular aggregates, from
their compact to their fragmented states, is parametrized by a single
collective radial parameter. Treating all the remaining particle coordinates in
d dimensions democratically, as a set of angles orthogonal to this collective
radius or by equivalent variables, bypasses all independent-particle
approximations. The invariance of the total kinetic energy under arbitrary
d-dimensional transformations which preserve the radial parameter gives rise to
novel quantum numbers and ladder operators interconnecting its eigenstates at
each value of the radial parameter.
We develop the systematics and technology of this approach, introducing the
relevant mathematics tutorially, by analogy to the familiar theory of angular
momentum in three dimensions. The angular basis functions so obtained are
treated in a manifestly coordinate-free manner, thus serving as a flexible
generalized basis for carrying out detailed studies of wavefunction evolution
in multi-particle systems.Comment: 37 pages, 2 eps figure
Investigation of contact deformation and wear characteristics of discrete track recording media
The even semester 2014/2015 Technical Information Engineering University of Semarang (USM) has been running the Competency Based Curriculum (CBC) in the management of learning. Conversions that occur in some subjects at an increase in scheduled meetings in the classroom or in the laboratory. Computer Networks is one of the subjects who experienced a conversion. In the curriculum in 2008, Computer Networking has a number of credits 3. From the 2 credits 3 credits are for credits 1 credits for theory and practical credits. While at the CBC in 2013, Computer Networking has 4 credits, with details of 2 credits 2 credits theory and practicum. As lecture and instructor Computer Network, researchers interested in studying the effect of applying the CBC in 2013 in the subje ct of Computer Network. Does the addition of meeting practical and theoretical material renewal in accordance with the expected competencies?. Researchers tried applying the CBC in 2013 by conducting action research. Implementation of the research was conducted during an ongoing lecture that even semester 2015/2016. The results of the study during the first half of researchers will compare with the achievements that never existed when the old curriculum still in use. The goals of this research is, subjects in the Computer Network has always been one of the subjects that the content of the material and its application in the lab was able to follow the needs of the workforc
Challenges in QCD matter physics - The Compressed Baryonic Matter experiment at FAIR
Substantial experimental and theoretical efforts worldwide are devoted to
explore the phase diagram of strongly interacting matter. At LHC and top RHIC
energies, QCD matter is studied at very high temperatures and nearly vanishing
net-baryon densities. There is evidence that a Quark-Gluon-Plasma (QGP) was
created at experiments at RHIC and LHC. The transition from the QGP back to the
hadron gas is found to be a smooth cross over. For larger net-baryon densities
and lower temperatures, it is expected that the QCD phase diagram exhibits a
rich structure, such as a first-order phase transition between hadronic and
partonic matter which terminates in a critical point, or exotic phases like
quarkyonic matter. The discovery of these landmarks would be a breakthrough in
our understanding of the strong interaction and is therefore in the focus of
various high-energy heavy-ion research programs. The Compressed Baryonic Matter
(CBM) experiment at FAIR will play a unique role in the exploration of the QCD
phase diagram in the region of high net-baryon densities, because it is
designed to run at unprecedented interaction rates. High-rate operation is the
key prerequisite for high-precision measurements of multi-differential
observables and of rare diagnostic probes which are sensitive to the dense
phase of the nuclear fireball. The goal of the CBM experiment at SIS100
(sqrt(s_NN) = 2.7 - 4.9 GeV) is to discover fundamental properties of QCD
matter: the phase structure at large baryon-chemical potentials (mu_B > 500
MeV), effects of chiral symmetry, and the equation-of-state at high density as
it is expected to occur in the core of neutron stars. In this article, we
review the motivation for and the physics programme of CBM, including
activities before the start of data taking in 2022, in the context of the
worldwide efforts to explore high-density QCD matter.Comment: 15 pages, 11 figures. Published in European Physical Journal
Varespladib and cardiovascular events in patients with an acute coronary syndrome: the VISTA-16 randomized clinical trial
IMPORTANCE: Secretory phospholipase A2(sPLA2) generates bioactive phospholipid products implicated in atherosclerosis. The sPLA2inhibitor varespladib has favorable effects on lipid and inflammatory markers; however, its effect on cardiovascular outcomes is unknown. OBJECTIVE: To determine the effects of sPLA2inhibition with varespladib on cardiovascular outcomes. DESIGN, SETTING, AND PARTICIPANTS: A double-blind, randomized, multicenter trial at 362 academic and community hospitals in Europe, Australia, New Zealand, India, and North America of 5145 patients randomized within 96 hours of presentation of an acute coronary syndrome (ACS) to either varespladib (n = 2572) or placebo (n = 2573) with enrollment between June 1, 2010, and March 7, 2012 (study termination on March 9, 2012). INTERVENTIONS: Participants were randomized to receive varespladib (500 mg) or placebo daily for 16 weeks, in addition to atorvastatin and other established therapies. MAIN OUTCOMES AND MEASURES: The primary efficacy measurewas a composite of cardiovascular mortality, nonfatal myocardial infarction (MI), nonfatal stroke, or unstable angina with evidence of ischemia requiring hospitalization at 16 weeks. Six-month survival status was also evaluated. RESULTS: At a prespecified interim analysis, including 212 primary end point events, the independent data and safety monitoring board recommended termination of the trial for futility and possible harm. The primary end point occurred in 136 patients (6.1%) treated with varespladib compared with 109 patients (5.1%) treated with placebo (hazard ratio [HR], 1.25; 95%CI, 0.97-1.61; log-rank P = .08). Varespladib was associated with a greater risk of MI (78 [3.4%] vs 47 [2.2%]; HR, 1.66; 95%CI, 1.16-2.39; log-rank P = .005). The composite secondary end point of cardiovascular mortality, MI, and stroke was observed in 107 patients (4.6%) in the varespladib group and 79 patients (3.8%) in the placebo group (HR, 1.36; 95% CI, 1.02-1.82; P = .04). CONCLUSIONS AND RELEVANCE: In patients with recent ACS, varespladib did not reduce the risk of recurrent cardiovascular events and significantly increased the risk of MI. The sPLA2inhibition with varespladib may be harmful and is not a useful strategy to reduce adverse cardiovascular outcomes after ACS. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT01130246. Copyright 2014 American Medical Association. All rights reserved
ЭФФЕКТ ВОЗДЕЙСТВИЯ 1,5-БИС(3,5-ДИМЕТИЛПИРАЗОЛ-1-ИЛ)-3-ОКСАПЕНТАН-ДИАЦЕТАТОМЕДИ НА ОБЩЕЕ СОСТОЯНИЕ ОРГАНИЗМА КРЫС В УСЛОВИЯХ ЭКСПЕРИМЕНТА
Многие производные пиразола проявляют разнообразные фармакологические свойства. Им характерны антиоксидантная, антивирусная активность, противовоспалительные, иммуномодулирующие свойства, а также антидепрессивный и противоопухолевый эффекты. Данная работа основана на результатах морфометрических показателей массы тела и печени и биохимического анализа крови здоровых взрослых самцов белых крыс после однократного и многократного внутрибрюшинного введения 1,5-бис(3,5-диметилпиразол-1-ил)-3-оксапентан-диацетатомеди, растворенного в свежеприготовленном физиологическом растворе (доза 12 мг / кг массы тела). Результаты исследования показали, что при введении препарата в организм крыс проявляются различные эффекты. Установлено, что исследуемое вещество имеет гипогликемический эффект, о чем свидетельствует снижение уровня глюкозы в крови и увеличение количества гликогена в печени. Антилиполитический его эффект подтверждается снижением уровня свободных жирных кислот в крови. Токсическое воздействие препарата проявляется повышением уровня печеночных ферментов аланин аминотрансферазы и аспартат аминотрансферазы, а также снижением уровня альбумина в сыворотке крови и уменьшением массы тела и печени. Эти эффекты проявляются и сохраняются только при многократном ежедневном применении этого препарата в течение 6 недель
Электрохимический синтез композиционных материалов на основе никеля, модифицированных наноразмерным оксидом алюминия
Electrochemical synthesis of nickel-based composite coatings and foil reinforced with nanosized aluminum oxide is reported. Ni-Al₂O₃ composites with different content of the modifying phase were prepared by chemical dispersion of aluminum oxide using the “from above down” principle. The influence of the aluminum oxide concentration in the electrolyte on the physicomechanical properties of the reinforced foil was determined. Incorporation of reinforcing phase particles into the metal matrix leads to a decrease in the grain size and enhances by a factor of 2–6 the strength characteristics of the coatings and foil. The topography of the surface and the cross section profile of the composites were examined, and the influence of these characteristics on the properties of the materials was determined.Представлены результаты электрохимического формирования композиционных покрытий и фольг на основе никеля, армированных наноразмерным оксидом алюминия. Для получения композитов Ni-Al₂O₃ с различным содержанием модифицирующей фазы использован метод химического диспергирования оксида алюминия по принципу сверху вниз. Установлено влияние концентрации оксида алюминия в электролите на физико-механические свойства армированных фольг. Включение в основную матрицу металла частиц армирующей фазы приводит к уменьшению размеров зерен и повышает в 2-6 раз прочностные характеристики покрытий и фольг. Изучена топография поверхности и профиль сечения композитов и установлено их влияние на свойства материалов
Phase field modelling voids nucleation and growth in binary systems
We present a comprehensive study of voids formation, nucleation and growth in
a prototype model of binary alloys subjected to irradiation by using a combined
approach based on phase field and rate theories. It is shown that voids
formation is caused by interaction of irradiation-produced vacancies through
elastic deformation of a lattice and vacancy coupling with composition field of
the alloy. Phase diagrams illustrating the formation of states related to solid
solution, phase decomposition, and patterning are obtained. Formation of voids
from supersaturated ensemble of vacancies is accompanied by composition
rearrangement of alloy components. It was found that elastic inhomogeneity
leading to the formation of anisotropic precipitates in an initially prepared
binary alloy results in the formation of a void super-lattice under
irradiation. It was shown that voids nucleate and grow with dose according to
diffusion controlled precipitation processes, where universal dynamics of voids
growth is revealed. Estimations of main quantitative and statistical
characteristics of voids by using material parameters relevant to most of
alloys and steels give good agreement with experimental observations.Comment: 21 pages, 10 figure
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