Probing the QCD Critical Point with Relativistic Heavy-Ion Collisions

We utilize an event-by-event relativistic hydrodynamic calculation performed at a number of different incident beam energies to investigate the creation of hot and dense QCD matter near the critical point. Using state-of-the-art analysis and visualization tools we demonstrate that each collision event probes QCD matter characterized by a wide range of temperatures and baryo-chemical potentials, making a dynamical response of the system to the vicinity of the critical point very difficult to isolate above the background.Comment: CPOD 2011 Proceeding

On the Use of Accelerated Molecular Dynamics to Enhance Configurational Sampling in Ab Initio Simulations

We have implemented the accelerated molecular dynamics approach (Hamelberg, D.; Mongan, J.; McCammon, J. A. J. Chem. Phys. 2004, 120 (24), 11919) in the framework of ab initio MD (AIMD). Using three simple examples, we demonstrate that accelerated AIMD (A-AIMD) can be used to accelerate solvent relaxation in AIMD simulations and facilitate the detection of reaction coordinates: (i) We show, for one cyclohexane molecule in the gas phase, that the method can be used to accelerate the rate of the chair-to-chair interconversion by a factor of ∼1 × 105, while allowing for the reconstruction of the correct canonical distribution of low-energy states; (ii) We then show, for a water box of 64 H2O molecules, that A-AIMD can also be used in the condensed phase to accelerate the sampling of water conformations, without affecting the structural properties of the solvent; and (iii) The method is then used to compute the potential of mean force (PMF) for the dissociation of Na−Cl in water, accelerating the convergence by a factor of ∼3−4 compared to conventional AIMD simulations.(2) These results suggest that A-AIMD is a useful addition to existing methods for enhanced conformational and phase-space sampling in solution. While the method does not make the use of collective variables superfluous, it also does not require the user to define a set of collective variables that can capture all the low-energy minima on the potential energy surface. This property may prove very useful when dealing with highly complex multidimensional systems that require a quantum mechanical treatment

Calculations Predict That Carbon Tunneling Allows the Degenerate Cope Rearrangement of Semibullvalene to Occur Rapidly at Cryogenic Temperatures

Article on calculations predicting that carbon tunneling allows the degenerate cope rearrangement of semibullvalene to occur rapidly at cryogenic temperatures

Polyyne Hybrid Compounds from Notopterygium incisum with Peroxisome Proliferator-Activated Receptor Gamma Agonistic Effects

[Image: see text] In the search for peroxisome proliferator-activated receptor gamma (PPARγ) active constituents from the roots and rhizomes of Notopterygium incisum, 11 new polyacetylene derivatives (1–11) were isolated. Their structures were elucidated by NMR and HRESIMS as new polyyne hybrid molecules of falcarindiol with sesquiterpenoid or phenylpropanoid moieties, named notoethers A–H (1–8) and notoincisols A–C (9–11), respectively. Notoincisol B (10) and notoincisol C (11) represent two new carbon skeletons. When tested for PPARγ activation in a luciferase reporter assay with HEK-293 cells, notoethers A–C (1–3), notoincisol A (9), and notoincisol B (10) showed promising agonistic activity (EC(50) values of 1.7 to 2.3 μM). In addition, notoincisol A (9) exhibited inhibitory activity on NO production of stimulated RAW 264.7 macrophages

Natural alpha interferon in multiple sclerosis : Results of three preliminary series

In three preliminary, sequential series conducted between 1987 – 1991, natural human leukocyte interferon-alpha [HuIFN(Le)] was evaluated in 49 interferon-naive multiple sclerosis (MS) patients. In this study, safety data are reported for all 49 patients, and efficacy data for 45 of 49, each patient having received 3 – 12 months of therapy during the initial study year with observation only in the second year. No major side-effects for HuIFN(Le) were observed at doses of 5 – 30 million international units (MIU) per week for 3 – 12 months, although severe fatigue caused some patient drop-outs prior to completion of 3 months of therapy. The relapse rate in patients having received HuIFN(Le), prospectively evaluated in two series (34 patients), was reduced by 80% at 2 years. An unexpected trend towards improved disability provoked a retrospective analysis. In the first year, 36 of 45 (80%) patients improved or stabilized ( P = 0.0001); of these 26 of 45 (58%) improved and 10 of 45 (22%) stabilized ( P = 0.0023, X2 = 9.3). In year 2, 34 of 45 (76%) were improved/stabilized ( P = 0.001); of these, 24 of 45 (53%) remained improved and 10 of 45 (22%) remained stable ( P = 0.01, X2 = 6.6). A trend to greater efficacy at the higher doses for longer periods of therapy, up to 12 months, was observed. [Formula: see text] Durant trois essais préliminaires séquentiels menés entre 1987 – 1991, on a examiné les effets de l'interféron alpha naturel des leucocytes humains [HuIFN(Le)] chez 49 patients atteints de sclérose en plaques (MS) qui n'avaient pas reçu ce type de traitement auparavant. Les données relatives à l'innocuité qui sont présentées se rapportent à l'ensemble des 49 patients, et celles relatives à l'efficacité ont été obtenues chez 45 des 49 malades, chacun ayant été soumis à 3 – 12 mois de traitement durant l'année initiale d'étude et les observations ayant été effectuées durant la seconde année seulement. Aucun effet secondaire majeur n'a été décrit avec l'HuIFN(Le) administré à des doses de 5 –30 millions d'unités internationales (MUI) par semaine pendant 3 – 12 mois, et ce bien qu'une fatigue sévère ait conduit à l'abandon de certains patients avant la fin des 3 mois de traitement. Le taux de récidive a été évalué à titre prospectif durant deux séries (34 patients) chez des malades qui avaient été traitès par l'HuIFN(Le), et une réduction de 80% a été enregistrée à 2 ans. L'incapacité a tendance à s'améliorer, un effet inattendu qui a conduit à la réalisation d'une analyse rétrospective. Durant la première année, 36 des 45 patients (80%) ont bénéficié d'une amélioration ou d'une stabilisation ( P = 0,0001), parmi lesquels 26 sur 45 (58%) ont présenté une amélioration, et 10 sur 45 (22%) une stabilisation ( P = 0,0023, x2 = 9,3). Durant la deuxième année, une amélioration/stabilisation a été observée chez 34 des 45 patients (76%) ( P = 0,001) puisqu'un maintien de 1'amélioration a été mis en évidence chez 24 sur 45 patients (53%) et un maintien de la stabilisation chez 10 sur 45 d'entre eux (22%) ( P = 0,01, X2 = 6,6). On a remarqué que les doses plus fortes ont tendance à être plus efficaces lorsque le traitement est prolongé (jusqu'à 12 mois). In drei vorläufigen, sequentiellen Serien die zwischen 1987 und 1991 durchgeführt wurden, wurde natürliches Human-Leukozyten Interferon-alpha [HuIFN(Le)] bei 49 Interferon-naiven Multiple Sklerose (MS) Patienten ausgewertet. In dieser Studie sind Sicherheitswerte für alie 49 Patienten dargestellt, und Wirksamkeitswerte für 45 von 49, wobei alle Patienten im ersten Studienjahr eine 3- bis 12- monatige Behandlung erhielten und die Observation erst im zweiten Jahr erfolgte. Es wurden keine wesentlichen Nebenwirkungen für HuIFN(Le) beobachtet bei Dosierungen von 5 – 30 Millionen Internationalen Einheiten (MIU) pro Woche über einen Zeitraum von 3 – 12 Monaten, obgleich schwere Fatigatio den Drop Out einiger Patienten noch vor Ablauf der dreimonatigen Therapie verursachte. Die Rückfallrate für Patienten die HuIFN(Le) erhalten hatten, prospektive ausgewertet in zwei Serien (34 Patienten), wurde an der Zweijahresmarke um 80% reduziert. Eine unerwartete Tendenz zu verbesserter Invalidität bewirkte eine rückwirkende Analyse. Im ersten Jahr verbesserte oder stabilisierte sich der Zustand von 36 Patienten von insgesamt 45 (80%) ( P = 0,0001); von diesen erfuhren 26 von 45 (58%) eine Verbesserung, 10 von 45 (22%) eine Stabilisierung ( P = 0,0023, x2 = 9,3). Im zweiten Jahr, ergab sich eine Besserung/Stabilisierung bie 34 von 45 (76%) ( P = 0,0001); von diesen dauerte bei 24 von 45 (53%) die Besserung, und bei 10 von 45 (22%) die Stabilisierung an ( P = 0,0023, x2 = 6,6). Eine Tendenz zu gesteigerter Wirksamkeit bei den höheren Dosierungen über längere Therapiezeiträume von bis zu 12 Monaten wurde beobachtet. </jats:p

^(15)N NMR Spectrum of a 1,1-Diazene. N-(2,2,6,6-Tetramethylpiperidyl)nitrene

The low-temperature ^(15)N NMR spectrum of the 1,1-diazene, N-(2,2,6,6-tetramethylpiperidyl)nitrene (l), is reported. The ^(15)N double- and mono-labeled 1,ldiazenes la and lb were synthesized. The nitrene and amino nitrogens of 1 have resonance in dimethyl ether at -90 ºC at 917.0 and 321.4 ppm, respectively, downfield from anhydrous ^(15)NH_3, affording a chemical shift difference of 595 ppm for the directly bonded nitrogen nuclei. The chemical shift of the ring nitrogen is consistent with an amino nitrogen whose lone pair is largely delocalized. The large downfield shift of the nitrene nitrogen is consistent with a large paramagnetic term due to a low-lying n → π^* transition