ABSTRACT
This Letter presents the first measurement of event-by-event fluctuations of the elliptic flow parameter v(2) in Au+Au collisions at square root(s(NN))=200 GeV as a function of collision centrality. The relative nonstatistical fluctuations of the v(2) parameter are found to be approximately 40%. The results, including contributions from event-by-event elliptic flow fluctuations and from azimuthal correlations that are unrelated to the reaction plane (nonflow correlations), establish an upper limit on the magnitude of underlying elliptic flow fluctuations. This limit is consistent with predictions based on spatial fluctuations of the participating nucleons in the initial nuclear overlap region. These results provide important constraints on models of the initial state and hydrodynamic evolution of relativistic heavy ion collisions.
ABSTRACT
A measurement of two-particle correlations with a high transverse momentum trigger particle (p(T)(trig) > 2.5 GeV/c) is presented for Au+Au collisions at square root(s(NN)) = 200 GeV over the uniquely broad longitudinal acceptance of the PHOBOS detector (-4 < Delta eta < 2). A broadening of the away-side azimuthal correlation compared to elementary collisions is observed at all Delta eta. As in p+p collisions, the near side is characterized by a peak of correlated partners at small angle relative to the trigger particle. However, in central Au+Au collisions an additional correlation extended in Delta eta and known as the "ridge" is found to reach at least |Delta eta| approximately = 4. The ridge yield is largely independent of Delta eta over the measured range, and it decreases towards more peripheral collisions. For the chosen (p(T)(trig) cut, the ridge yield is consistent with zero for events with less than roughly 100 participating nucleons.
ABSTRACT
We present the first measurements of the pseudorapidity distribution of primary charged particles in Cu+Cu collisions as a function of collision centrality and energy, sqrt[s_{NN}]=22.4, 62.4, and 200 GeV, over a wide range of pseudorapidity, using the PHOBOS detector. A comparison of Cu+Cu and Au+Au results shows that the total number of produced charged particles and the rough shape (height and width) of the pseudorapidity distributions are determined by the number of nucleon participants. More detailed studies reveal that a more precise matching of the shape of the Cu+Cu and Au+Au pseudorapidity distributions over the full range of pseudorapidity occurs for the same N{part}/2A rather than the same N_{part}. In other words, it is the collision geometry rather than just the number of nucleon participants that drives the detailed shape of the pseudorapidity distribution and its centrality dependence at RHIC energies.
ABSTRACT
This Letter presents measurements of the elliptic flow of charged particles as a function of pseudorapidity and centrality from Cu-Cu collisions at 62.4 and 200 GeV using the PHOBOS detector at the Relativistic Heavy Ion Collider. The elliptic flow in Cu-Cu collisions is found to be significant even for the most central events. For comparison with the Au-Au results, it is found that the detailed way in which the collision geometry (eccentricity) is estimated is of critical importance when scaling out system-size effects. A new form of eccentricity, called the participant eccentricity, is introduced which yields a scaled elliptic flow in the Cu-Cu system that has the same relative magnitude and qualitative features as that in the Au-Au system.
ABSTRACT
The aim of this study is to evaluate the application of phospholipid liposomes in HCl--induced RDS in rabbits. Acute respiratory distress syndrome was induced by administration of 0.2 N HCl via intratracheal instillation for 45 min. After induced ARDS animals under artificial lung ventilation were retreated with liposomes for 60 min. Arterial blood gas analysis was performed at 30, 45 and 60 min after liposome application. Untreated animals were ventilated for the same time. Rabbits were killed with thiopental and bronhoalveolar lavage fluid biochemical and biophysical parameters were investigated. HCl- lung injury caused decrease of arterial oxygen pressure/ fraction of inspired oxygen ratio more than 50% compared to the control. We obtained high respiratory acidosis as well. The instillation of liposomes led to reversion of gas exchange at 60 min. after application almost to the control value. In order to characterize the rabbit lung tissue changes after HCl-treatment histological and ultra thin slices were obtained. Electron microscopic preparations demonstrate disappearance of surface active film in treated animals. Application of liposomes led to visualization of osmophilic material forming lamellae in lamellar bodies. On the basis of the results obtained we may assume that it is likely that the liposomes assessed in this study might be used for in vivo improvement of oxygenation in acid aspiration induced ARDS.
Subject(s)
Acidosis, Respiratory/etiology , Lung/drug effects , Phospholipids/therapeutic use , Respiratory Distress Syndrome/drug therapy , Acidosis, Respiratory/blood , Animals , Biophysical Phenomena , Biophysics , Blood Gas Analysis , Bronchoalveolar Lavage Fluid/chemistry , Disease Models, Animal , Liposomes , Lung/ultrastructure , Male , Microscopy, Electron , Phospholipids/administration & dosage , Rabbits , Respiratory Distress Syndrome/blood , Respiratory Distress Syndrome/complications , Respiratory Distress Syndrome/pathologyABSTRACT
Surfactant therapy leads to significant clinical improvement in infants at risk for, or having, respiratory distress syndrome (RDS). The development of exogenous surfactant (ES) as a therapy for neonatal respiratory disorders was a significant advance in neonatal intensive care that has led to a decrease in neonatal mortality. Two broad categories of surfactants are available for exogenous therapy: surfactants derived from animal sources or 'natural' surfactants; and synthetic surfactants. The physical properties of natural and synthetic surfactants have been studied using techniques such as the Wilhelmy surface balance and the bilayer black film (BBF) method. Here we report some data from a comparative study of ES (Exosurf, Survanta, Curosurf and Alveofact) and clinical samples of tracheal aspirate (TA) of newborns with RDS treated with Curosurf. Measured interfacial physico-chemical parameters prove "better" properties in vitro of the surfactant proteins (SP-B and SP-C) containing preparations Curosurf and Alveofact. Their properties are similar, Alveofact showing a higher surface tension lowering capacity under dynamic conditions. A compendious comparison of results for dynamic surface properties of monolayers of TA from newborns treated with Curosurf with data for newborns treated with Exosurf is presented. Both ES yield the desired lowering of the surface tension during cyclic film compression, being larger after treatment with Curosurf. Observations concerning the properties of BFF of ES (dependence on surfactant concentration, adsorption time, film drainage time and BFF formation time) are also reported and discussed.
Subject(s)
Models, Biological , Pulmonary Surfactants , Respiratory Distress Syndrome, Newborn/drug therapy , Animals , Biological Products/chemistry , Biological Products/pharmacology , Biological Products/therapeutic use , Biophysical Phenomena , Biophysics , Drug Combinations , Fatty Alcohols/chemistry , Fatty Alcohols/pharmacology , Fatty Alcohols/therapeutic use , Humans , Infant, Newborn , Lipids/chemistry , Lipids/pharmacology , Lipids/therapeutic use , Phospholipids/chemistry , Phospholipids/pharmacology , Phospholipids/therapeutic use , Phosphorylcholine/chemistry , Phosphorylcholine/pharmacology , Phosphorylcholine/therapeutic use , Polyethylene Glycols/chemistry , Polyethylene Glycols/pharmacology , Polyethylene Glycols/therapeutic use , Pulmonary Surfactants/chemistry , Pulmonary Surfactants/pharmacology , Pulmonary Surfactants/therapeutic use , Respiratory Distress Syndrome, Newborn/metabolism , Surface Tension/drug effectsABSTRACT
We report on measurements of directed flow as a function of pseudorapidity in Au + Au collisions at energies of square root of SNN = 19.6, 62.4, 130 and 200 GeV as measured by the PHOBOS detector at the BNL Relativistic Heavy Ion Collider. These results are particularly valuable because of the extensive, continuous pseudorapidity coverage of the PHOBOS detector. There is no significant indication of structure near midrapidity and the data surprisingly exhibit extended longitudinal scaling similar to that seen for elliptic flow and charged particle pseudorapidity density.
ABSTRACT
We present transverse momentum distributions of charged hadrons produced in Cu + Cu collisions at square root of SNN = 62.4 and 200 GeV. The spectra are measured for transverse momenta of 0.25 < pT < 5.0 GeV/c at square root of SNN = 62.4 GeV and 0.25 < pT < 7.0 GeV/c at square root of SNN = 200 GeV, in a pseudorapidity range of 0.2 < eta < 1.4. The nuclear modification factor R(AA) is calculated relative to p + p data at both collision energies as a function of collision centrality. At a given collision energy and fractional cross section, R(AA) is observed to be systematically larger in Cu + Cu collisions compared to Au + Au. However, for the same number of participating nucleons, R(AA) is essentially the same in both systems over the measured range of pT, in spite of the significantly different geometries of the Cu + Cu and Au + Au systems.
ABSTRACT
This Letter describes the measurement of the energy dependence of elliptic flow for charged particles in Au+Au collisions using the PHOBOS detector at the Relativistic Heavy Ion Collider. Data taken at collision energies of square root of s(NN)=19.6, 62.4, 130, and 200 GeV are shown over a wide range in pseudorapidity. These results, when plotted as a function of eta(')=|eta|-y(beam), scale with approximate linearity throughout eta('), implying no sharp changes in the dynamics of particle production as a function of pseudorapidity or increasing beam energy.
ABSTRACT
We have measured transverse momentum distributions of charged hadrons produced in Au+Au collisions at sqrt[s(NN)]=62.4 GeV. The spectra are presented for transverse momenta 0.25
ABSTRACT
The measured pseudorapidity distribution of primary charged particles in minimum-bias d+Au collisions at sqrt[s(NN)]=200 GeV is presented for the first time. This distribution falls off less rapidly in the gold direction as compared to the deuteron direction. The average value of the charged particle pseudorapidity density at midrapidity is
ABSTRACT
We have measured transverse momentum distributions of charged hadrons produced in d+Au collisions at sqrt[s(NN)]=200 GeV. The spectra were obtained for transverse momenta 0.25
ABSTRACT
We present measurements of the pseudorapidity distribution of primary charged particles produced in Au+Au collisions at three energies, sqrt[s(NN)]=19.6, 130, and 200 GeV, for a range of collision centrali-ties. The distribution narrows for more central collisions and excess particles are produced at high pseudorapidity in peripheral collisions. For a given centrality, however, the distributions are found to scale with energy according to the "limiting fragmentation" hypothesis. The universal fragmentation region described by this scaling grows in pseudorapidity with increasing collision energy, extending well away from the beam rapidity and covering more than half of the pseudorapidity range over which particles are produced. This approach to a universal limiting curve appears to be a dominant feature of the pseudorapidity distribution and therefore of the total particle production in these collisions.
ABSTRACT
This paper describes the measurement of collective flow for charged particles in Au+Au collisions at sqrt[s(NN)]=130 GeV using the PHOBOS detector at the Relativistic Heavy Ion Collider (RHIC). The measured azimuthal hit anisotropy is presented over a wide range of pseudorapidity (-5.0
ABSTRACT
We present the first measurement of the pseudorapidity density of primary charged particles in Au+Au collisions at root square[s(NN)] = 200 GeV. For the 6% most central collisions, we obtain dN(ch)/d(eta)/(/eta/<1) = 650+/-35(syst). Compared to collisions at root square[s(NN)] = 130 GeV, the highest energy studied previously, an increase by a factor of 1.14+/-0.05 at 90% confidence level, is found. The energy dependence of the pseudorapidity density is discussed in comparison with data from proton-induced collisions and theoretical predictions.
Subject(s)
Adjuvants, Immunologic/pharmacology , Anti-Infective Agents/pharmacology , Infections/drug therapy , Infections/immunology , Adjuvants, Immunologic/therapeutic use , Animals , Anti-Infective Agents/therapeutic use , Anti-Inflammatory Agents/pharmacology , Anti-Inflammatory Agents/therapeutic use , HumansABSTRACT
The results of treatment of 63 injured persons with thoracicoabdominal trauma were analyzed. Injured persons with severe trauma and pronounced infringements of hemodynamic (41.25%); with severe injury of inferior organs and stable hemodynamical indexes (47.62%), light injury (11.12%) were detailed. Algorithm of curative-diagnostical measures for every group was elaborated. Among the injured persons 11 (17.46%) died.
Subject(s)
Abdominal Injuries/epidemiology , Abdominal Injuries/surgery , Thoracic Injuries/epidemiology , Thoracic Injuries/surgery , Abdominal Injuries/diagnosis , Adolescent , Adult , Aged , Aged, 80 and over , Female , Humans , Male , Middle Aged , Thoracic Injuries/diagnosis , Treatment OutcomeABSTRACT
Multifactor analysis of the lomefloxacin effect on the primary immune response to T-independent bacterial antigen (vaccine EV fraction 1) and to T-dependent cellular antigen (SRBC) in mice was performed with the use of a wide range of the antibiotic concentrations and the dosage time. It was shown that lomefloxacin in the doses corresponding to the average therapeutic ones used for 3-9 days had no effect on the content of the IgG antibodies, was able to increase the level of the IgM antibodies and insignificantly lowered the concentration of the IgA antibodies.
Subject(s)
Anti-Infective Agents/pharmacology , Antigens, Bacterial/immunology , Fluoroquinolones , Hemagglutinins/immunology , Immunoglobulins/biosynthesis , Quinolones/pharmacology , Animals , Erythrocytes/immunology , Immunization , Immunoglobulin A/biosynthesis , Immunoglobulin G/biosynthesis , Immunoglobulin M/biosynthesis , Mice , SheepABSTRACT
The in vitro effect of lomefloxacin within the wide dose ranges from 0.1 to 100 micrograms/ml on luminol-dependent chemiluminescence and adherence of polymorphonuclear leukocytes of guinea pigs was studied under two different conditions: during the cell incubation in the presence of various concentrations of the drug and after the cell washing to remove lomefloxacin. In concentrations of 10 and 100 micrograms/ml the drug inhibited the response under the both conditions while in a concentration of 1 microgram/ml it stimulated the chemiluminescence. In concentrations of 0.1 to 100 micrograms/ml lomefloxacin stimulated the leukocyte adherence. The highest stimulation was observed with the use of the drug in a concentration of 1 microgram/ml.