Narrowing of the balance function with centrality in Au+Au collisions at the square root of SNN = 130 GeV

The balance function is a new observable based on the principle that charge is locally conserved when particles are pair produced. Balance functions have been measured for charged particle pairs and identified charged pion pairs in Au+Au collisions at the square root of SNN = 130 GeV at the Relativistic Heavy Ion Collider using STAR. Balance functions for peripheral collisions have widths consistent with model predictions based on a superposition of nucleon-nucleon scattering. Widths in central collisions are smaller, consistent with trends predicted by models incorporating late hadronization.

Effect of graduated elastic compression stockings on leg symptoms and signs during exercise in patients with deep venous thrombosis: a randomized cross-over trial

Graduated elastic compression stockings (ECS) are often prescribed after deep venous thrombosis (DVT) to alleviate acute symptoms and to prevent and treat post-thrombotic syndrome (PTS). In patients with DVT, leg symptoms tend to worsen with exercise. The effects of ECS use during exercise have not been studied. Objectives were to determine whether ECS improve symptoms and signs and increase exercise capacity when worn during treadmill exercise by patients with prior DVT, with or without PTS. The methods employed a randomized cross-over trial. We recruited subjects who had a first episode of unilateral DVT at least 1 year earlier and categorized them as having, or not having, the PTS using a validated scale. Subjects underwent two identical treadmill exercise sessions at least 1 week apart, and were randomly assigned to wear knee-length 30 mmHg ECS on the affected leg during one of the two sessions. Venous symptoms, leg volume, leg circumference and calf muscle flexibility were measured in the affected leg before and after both exercise sessions. Subjects achieved similar percentage maximum predicted heart rates during both sessions. Comparing the ECS to no ECS session, there were no significant differences in treadmill time (21.2 vs. 21.2 min, P = 0.94), gain in leg volume (71 vs. 73 mL, P = 0.83), or change in soleus or gastrocnemius flexibility, whether or not PTS was present. Symptoms in general worsened slightly with exercise regardless of whether or not ECS were worn and did not differ according to PTS status. Per-subject analysis showed that use of ECS resulted in global improvement of symptoms in 25% of subjects, global worsening in 33% of subjects, and had no or inconsistent effects in 42% of subjects. Whether or not PTS was present, the use of ECS during exercise by patients with prior DVT did not improve symptoms and signs during exercise or increase exercise capacity.

Disappearance of back-to-back high-pT hadron correlations in central Au+Au collisions at sqrt[s NN ] =200 GeV

Azimuthal correlations for large transverse momentum charged hadrons have been measured over a wide pseudorapidity range and full azimuth in Au+Au and p+p collisions at sqrt[s(NN)]=200 GeV. The small-angle correlations observed in p+p collisions and at all centralities of Au+Au collisions are characteristic of hard-scattering processes previously observed in high-energy collisions. A strong back-to-back correlation exists for p+p and peripheral Au+Au. In contrast, the back-to-back correlations are reduced considerably in the most central Au+Au collisions, indicating substantial interaction as the hard-scattered partons or their fragmentation products traverse the medium.

Azimuthal anisotropy and correlations in the hard scattering regime at RHIC

Azimuthal anisotropy (v(2)) and two-particle angular correlations of high p(T) charged hadrons have been measured in Au+Au collisions at sqrt[s(NN)]=130 GeV for transverse momenta up to 6 GeV/c, where hard processes are expected to contribute significantly. The two-particle angular correlations exhibit elliptic flow and a structure suggestive of fragmentation of high p(T) partons. The monotonic rise of v(2)(p(T)) for p(T)<2 GeV/c is consistent with collective hydrodynamical flow calculations. At p(T)>3 GeV/c, a saturation of v(2) is observed which persists up to p(T)=6 GeV/c.

Coherent rho(0) production in ultraperipheral heavy-ion collisions

The STAR Collaboration reports the first observation of exclusive rho(0) photoproduction, AuAu-->AuAurho(0), and rho(0) production accompanied by mutual nuclear Coulomb excitation, AuAu-->Au*Au*rho(0), in ultraperipheral heavy-ion collisions. The rho(0) have low transverse momenta, consistent with coherent coupling to both nuclei. The cross sections at sqrt[s(NN)]=130 GeV agree with theoretical predictions treating rho(0) production and Coulomb excitation as independent processes.

Centrality dependence of high-p(T) hadron suppression in Au+Au collisions at sqrt[s(NN)]=130 GeV

Inclusive transverse momentum distributions of charged hadrons within 0.2<p(T)<6.0 GeV/c have been measured over a broad range of centrality for Au+Au collisions at sqrt[s(NN)]=130 GeV. Hadron yields are suppressed at high p(T) in central collisions relative to peripheral collisions and to a nucleon-nucleon reference scaled for collision geometry. Peripheral collisions are not suppressed relative to the nucleon-nucleon reference. The suppression varies continuously at intermediate centralities. The results indicate significant nuclear medium effects on high-p(T) hadron production in heavy-ion collisions at high energy.

Azimuthal anisotropy of K(0)(S) and Lambda+Lambda production at midrapidity from Au+Au collisions at sqrt[s(NN)]=130 GeV

We report STAR results on the azimuthal anisotropy parameter v(2) for strange particles K(0)(S), Lambda, and Lambda at midrapidity in Au+Au collisions at sqrt[s(NN)]=130 GeV at the Relativistic Heavy Ion Collider. The value of v(2) as a function of transverse momentum, p(t), of the produced particle and collision centrality is presented for both particles up to p(t) approximately 3.0 GeV/c. A strong p(t) dependence in v(2) is observed up to 2.0 GeV/c. The v(2) measurement is compared with hydrodynamic model calculations. The physics implications of the p(t) integrated v(2) magnitude as a function of particle mass are also discussed.

Midrapidity Lambda and Lambda(macro) production in Au+Au collisions at the square root of [s(NN)]=130 GeV

We report the first measurement of strange (Lambda) and antistrange (Lambda macro) baryon production from square root of [s(NN)]=130 GeV Au+Au collisions at the Relativistic Heavy Ion Collider (RHIC). Rapidity density and transverse mass distributions at midrapidity are presented as a function of centrality. The yield of Lambda and Lambda; hyperons is found to be approximately proportional to the number of negative hadrons. The production of Lambda; hyperons relative to negative hadrons increases very rapidly with transverse momentum. The magnitude of the increase cannot be described by existing hadronic string fragmentation models alone.

Longitudinal flow of protons from (2-8)A GeV central Au+Au collisions

Rapidity distributions of protons from central 197Au+197Au collisions measured by the E895 Collaboration in the energy range from (2-8)A GeV at the Brookhaven AGS are presented. Longitudinal flow parameters derived using a thermal model including collective longitudinal expansion are extracted from these distributions. The results show an approximately linear increase in the longitudinal flow velocity, <betagamma>(L), as a function of the logarithm of beam energy.

Measurement of inclusive antiprotons from Au+Au collisions at square root of s(NN) = 130 GeV

We report the first measurement of inclusive antiproton production at midrapidity in Au+Au collisions at square root of s(NN) = 130 GeV by the STAR experiment at RHIC. The antiproton transverse mass distributions in the measured transverse momentum range of 0.25<p( perpendicular)<0.95 GeV/c are found to fall less steeply for more central collisions. The extrapolated antiproton rapidity density is found to scale approximately with the negative hadron multiplicity density.

d Macro and (3)He macro production in square root of s(NN) = 130 GeV Au+Au collisions

The first measurements of light antinucleus production in Au+Au collisions at the Relativistic Heavy-Ion Collider are reported. The observed production rates for d macro and (3)He macro are much larger than in lower energy nucleus-nucleus collisions. A coalescence model analysis of the yields indicates that there is little or no increase in the antinucleon freeze-out volume compared to collisions at CERN SPS energy. These analyses also indicate that the (3)He macro freeze-out volume is smaller than the d macro freeze-out volume.

Electrophoretic behavior of a highly water-soluble dendro[60]fullerene

The aim of the present study was to develop an analytical method for measuring amounts of a dendro[60]fullerene (DF) which is a highly water-soluble [60]fullerene derivative. We tried to define a straightforward methodology using capillary zone electrophoresis, a method which, to our knowledge, has not yet been used to that purpose. Preliminary assays showed that DF has almost the same mobility than the electroosmotic flow (EOF) but in the opposite direction. Attempts were carried out to reduce the EOF and positive results were obtained by adding hydroxypropylcellulose to the background electrolyte. In order to define optimal operating conditions, a Taguchi experimental plan was used to study simultaneously the effects of the main parameters that are pH, ionic strength, methanol amount and hydroxypropylcellulose concentration. Two parameters are of the utmost importance as to their effect on the migration time and separation efficiecy: pH and ionic strength whose actions are opposite.

Increased brain natriuretic peptide as a marker for right ventricular dysfunction in acute pulmonary embolism

Right ventricular (RV) function is of major prognostic significance in patients with acute pulmonary embolism (PE). The aim of the present study was to evaluate the role of neurohormone plasma brain natriuretic peptide (BNP) in assessing RV function in patients with acute PE. BNP levels were measured in 16 consecutive patients with acute PE as diagnosed by high probability lung scintigraphy or pulmonary angiography. Twelve healthy age-matched volunteers served as controls. All 16 patients underwent standard echocardiography and blood tests during the first hour of presentation. In the patient group, survival was studied for a period of 30 days. Plasma BNP levels in patients with acute PE were higher than in controls (7.2 [95% CI 0.4 to 144.6] versus 1.4[95% CI 0.4 to 4.6] pmol/L, p = 0.0008). Plasma BNP was significantly higher in 5 patients with RV dysfunction compared to II patients with normal RV function (40.2 [95% CI 7.5 to 214.9] versus 3.3 [95% CI 0.4 to 24.9] pmol/L, p = 0.0003). RV systolic pressure was not significantly correlated with BNP (r = 0.42, p = ns). In conclusion, plasma BNP neurohormone levels might be of clinical importance as a supplementary tool for assessment of RV function in patients with acute PE.

Root coverage and pocket reduction as combined surgical procedures

BACKGROUND

One of the main objectives of periodontal reconstructive surgery is the coverage of exposed roots due to gingival recession. A large variety of mucogingival grafting procedures are available that give highly predictable and esthetically acceptable results when treating intact root surfaces. However, these procedures call for a second surgery site in the palate. The present study examines a series of cases in which connective tissue, obtained from the tuberosity during pocket reduction procedures in the posterior region of the maxilla, was used for root coverage.

METHODS

Forty-four teeth from 25 patients with gingival recession of 3.30 +/- 0.14 mm (mean +/- SEM) were treated with subepithelial connective tissue grafts using connective tissue obtained from the tuberosity area during pocket reduction procedures in the posterior region of the maxilla.

RESULTS

The mean root coverage recession after treatment was 0.16 +/- 0.06 mm, with effectiveness of coverage at 95.0% +/- 1.84 and a predictability of 84.1%. Periodontal probing depth reduction at the donor site was 4.08 +/- 0.24 mm.

CONCLUSIONS

These results indicate that the subepithelial connective tissue graft obtained from the tuberosity area during pocket reduction procedures in the posterior region of the maxilla provides a very predictable and esthetic root coverage without the need for a second surgical site.

Multiplicity distribution and spectra of negatively charged hadrons in Au+Au collisions at square root of (sNN) = 130 GeV

The minimum-bias multiplicity distribution and the transverse momentum and pseudorapidity distributions for central collisions have been measured for negative hadrons ( h(-)) in Au+Au interactions at square root of ([s(NN)]) = 130 GeV. The multiplicity density at midrapidity for the 5% most central interactions is dN(h(-))/d(eta)/(eta = 0) = 280+/-1(stat)+/-20(syst), an increase per participant of 38% relative to pp collisions at the same energy. The mean transverse momentum is 0.508+/-0.012 GeV/c and is larger than in central Pb+Pb collisions at lower energies. The scaling of the h(-) yield per participant is a strong function of p( perpendicular). The pseudorapidity distribution is almost constant within /eta/<1.

Model-independent source imaging using two-pion correlations in (2 to 8)a GeV Au+Au collisions

We report a particle source imaging analysis based on two-pion correlations in high multiplicity Au+Au collisions at beam energies between 2A and 8A GeV. We apply the imaging technique introduced by Brown and Danielewicz, which allows a model-independent extraction of source functions with useful accuracy out to relative pion separations of about 20 fm. The extracted source functions have Gaussian shapes. Values of source functions at zero separation are almost constant across the energy range under study. Imaging results are found to be consistent with conventional source parameters obtained from a multidimensional Hanburg-Brown-Twiss analysis.

Pion Interferometry of square root of (s(NN)) =130 GeV Au + Au collisions at RHIC

Two-pion correlation functions in Au+Au collisions at square root of [s(NN)] = 130 GeV have been measured by the STAR (solenoidal tracker at RHIC) detector. The source size extracted by fitting the correlations grows with event multiplicity and decreases with transverse momentum. Anomalously large sizes or emission durations, which have been suggested as signals of quark-gluon plasma formation and rehadronization, are not observed. The Hanbury Brown-Twiss parameters display a weak energy dependence over a broad range in square root of [s(NN)].

Increased brain and atrial natriuretic peptides in patients with chronic right ventricular pressure overload: correlation between plasma neurohormones and right ventricular dysfunction

OBJECTIVE

To evaluate the role of plasma neurohormones in the diagnosis of asymptomatic or minimally symptomatic right ventricular dysfunction.

SETTING

Tertiary cardiovascular referral centre.

METHODS

Plasma brain natriuretic peptide (BNP) and atrial natriuretic peptide (ANP) concentrations were measured in 21 asymptomatic or minimally symptomatic patients with chronic right ventricular pressure overload caused by congenital heart disease, and in seven healthy volunteers. Right ventricular ejection fraction was determined using magnetic resonance imaging.

RESULTS

Right ventricular ejection fraction in the volunteers was higher than in the patients (69.0 (8.2)% v 58.0(12.0)%, respectively; p < 0.006). Left ventricular ejection fraction was 72.3(7.8)% in volunteers and 68.1(11.0)% in patients (NS). There was a significant difference between patients and volunteers in the plasma concentrations of BNP (5.3 (3.5) v 2.3 (1.7) pmol/l, respectively; p < 0.009) and ANP (7.3 (4.5)v 3.6 (1.4) pmol/l; p < 0.05). In both patients and volunteers, mean plasma ANP was higher than mean plasma BNP. Right ventricular ejection fraction was inversely correlated with BNP and ANP (respectively, r = 0.65; p < 0.0002 and r = 0.61; p < 0.002). There was no correlation between left ventricular ejection fraction and BNP (r = 0.2; NS) or ANP (r = 0.52; NS). Similarly, no correlation was shown between the level of right ventricular systolic pressure and either plasma BNP (r = 0.20) or plasma ANP (r = 0.07).

CONCLUSIONS

There was a significant inverse correlation between right ventricular ejection fraction and the plasma neurohormones BNP and ANP in asymptomatic or minimally symptomatic patients with right ventricular pressure overload and congenital heart disease. Monitoring changes in BNP and ANP may provide quantitative follow up of right ventricular dysfunction in these patients.

Increased brain and atrial natriuretic peptides in patients with chronic right ventricular pressure overload: correlation between plasma neurohormones and right ventricular dysfunction

OBJECTIVE

To evaluate the role of plasma neurohormones in the diagnosis of asymptomatic or minimally symptomatic right ventricular dysfunction.

SETTING

Tertiary cardiovascular referral centre.

METHODS

Plasma brain natriuretic peptide (BNP) and atrial natriuretic peptide (ANP) concentrations were measured in 21 asymptomatic or minimally symptomatic patients with chronic right ventricular pressure overload caused by congenital heart disease, and in seven healthy volunteers. Right ventricular ejection fraction was determined using magnetic resonance imaging.

RESULTS

Right ventricular ejection fraction in the volunteers was higher than in the patients (69.0 (8.2)% v 58.0(12.0)%, respectively; p < 0.006). Left ventricular ejection fraction was 72.3(7.8)% in volunteers and 68.1(11.0)% in patients (NS). There was a significant difference between patients and volunteers in the plasma concentrations of BNP (5.3 (3.5) v 2.3 (1.7) pmol/l, respectively; p < 0.009) and ANP (7.3 (4.5) v 3.6 (1.4) pmol/l; p < 0.05). In both patients and volunteers, mean plasma ANP was higher than mean plasma BNP. Right ventricular ejection fraction was inversely correlated with BNP and ANP (respectively, r = 0.65; p < 0.0002 and r = 0.61; p < 0.002). There was no correlation between left ventricular ejection fraction and BNP (r = 0.2; NS) or ANP (r = 0.52; NS). Similarly, no correlation was shown between the level of right ventricular systolic pressure and either plasma BNP (r = 0.20) or plasma ANP (r = 0.07).

CONCLUSIONS

There was a significant inverse correlation between right ventricular ejection fraction and the plasma neurohormones BNP and ANP in asymptomatic or minimally symptomatic patients with right ventricular pressure overload and congenital heart disease. Monitoring changes in BNP and ANP may provide quantitative follow up of right ventricular dysfunction in these patients.