In vitro study of the inactivation by dentine of some endodontic medicaments and their bases

BACKGROUND

The aim of this study was to investigate the antimicrobial effect of endodontic medicaments and their bases in the presence of dentine powder.

METHODS

The medicaments tested were Ledermix paste, Pulpdent paste, a 50:50 combination of the Pulpdent:Ledermix and their bases. The test organism was Enterococcus faecalis ATCC 29212. The presence or absence of dentine was examined as well as the effect of autoclaving dentine. Serial dilutions of samples at 1 hour, 1 day and 3 days were used for colony counting. The effects of dentine powder on pH for saturated Ca(OH)2 solution and Pulpdent paste at 1 hour and 24 hours were also measured.

RESULTS

Pulpdent and the 50:50 combination of Pulpdent:Ledermix completely inhibited the growth of E. faecalis from 1 hour onwards, and these results were not affected by the presence/absence of dentine powder, pre-incubation period, timing of autoclaving, or exposure time. Saturated solutions of Ca(OH)2 are prone to inactivation by dentine powder unlike Pulpdent paste. Ledermix paste took 3 days to exert a significant effect on the growth of E. faecalis.

CONCLUSIONS

In this laboratory study, both Pulpdent and the 50:50 mixture of Pulpdent with Ledermix were effective medicaments against E. faecalis in the presence of dentine powder.

Event-by-event fluctuations of azimuthal particle anisotropy in Au+Au collisions at square root(sNN) = 200 GeV

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.

High transverse momentum triggered correlations over a large pseudorapidity acceptance in Au + Au collisions at square root(s(NN)) = 200 GeV

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.

Ventricular rupture secondary to cardiac metastasis of transitional cell carcinoma of the bladder

We report a patient with transitional cell carcinoma of the bladder who had metastatic nodules in the myocardium of the left ventricle and tumour emboli in the left circumflex artery which caused myocardial infarction with ventricular rupture and haemopericardium. Cardiac metastasis of transitional cell carcinoma of the bladder is discussed and the literature reviewed.

Challenging endoscopy reprocessing guidelines: a prospective study investigating the safe shelf life of flexible endoscopes in a tertiary gastroenterology unit

BACKGROUND AND STUDY AIMS

Professional practice guidelines for endoscope reprocessing recommend reprocessing endoscopes between each case and proper storage following reprocessing after the last case of the list. There is limited empirical evidence to support the efficacy of endoscope reprocessing prior to use in the first case of the day; however, internationally, many guidelines continue to recommend this practice. The aim of this study is to estimate a safe shelf life for flexible endoscopes in a high-turnover gastroenterology unit.

MATERIALS AND METHODS

In a prospective observational study, all flexible endoscopes in active service during the 3-week study period were microbiologically sampled prior to reprocessing before the first case of the day (n = 200). The main outcome variables were culture status, organism cultured, and shelf life.

RESULTS

Among the total number of useable samples (n = 194), the overall contamination rate was 15.5%, with a pathogenic contamination rate of 0.5%. Mean time between last case one day and reprocessing before the first case on the next day (that is, shelf life) was 37.62 h (SD 36.47). Median shelf life was 18.8 h (range 5.27-165.35 h). The most frequently identified organism was coagulase-negative Staphylococcus, an environmental nonpathogenic organism.

CONCLUSIONS

When processed according to established guidelines, flexible endoscopes remain free from pathogenic organisms between last case and next day first case use. Significant reductions in the expenditure of time and resources on reprocessing endoscopes have the potential to reduce the restraints experienced by high-turnover endoscopy units and improve service delivery.

System size, energy, pseudorapidity, and centrality dependence of elliptic flow

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.

Use of Elastin Fibres Detected in Non-Directed Low Volume Bronchial Lavage in Ventilated ICU Patients

Elastin fibres in sputum have been described as a more sensitive marker of pulmonary necrosis than plain chest X-rays. This study aimed to determine the prevalence of elastin fibres using non-directed non-protected mini-bronchoalveolarlavage (BM-BAL) in mechanically ventilated patients in the intensive care unit. Patients admitted to the general intensive care unit of a tertiary referral hospital requiring more than 48 hours of mechanical ventilation had surveillance BM-BAL performed on admission and were then examined weekly using potassium hydroxide wet preparations for the presence of elastin fibres. All positive and a random selection of 16 negative preparations from patients with acute respiratory distress syndrome or pneumonia were fixed and examined using Weigert's staining method for elastin. Of 412 patients enrolled, 130 (32%) had pneumonia on admission, 50 (12%) developed 58 episodes of ventilator-associated pneumonia and acute respiratory distress syndrome was diagnosed in 86 patients (21%). No chest X-ray showed cavitating infiltrates. Of 985 specimens examined, only seven had elastin fibres. Elastin fibres are uncommonly found using BM-BAL in general screening, acute respiratory distress syndrome or pneumonia in the intensive care unit, the incidence too low to be a useful indicator of pulmonary necrosis.

Energy dependence of directed flow over a wide range of pseudorapidity in Au + Au collisions at the BNL Relativistic Heavy Ion Collider

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.

Energy dependence of elliptic flow over a large pseudorapidity range in Au+Au collisions at the BNL relativistic heavy ion collider

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.

Centrality dependence of charged hadron transverse momentum spectra in Au+Au collisions from sqrt[s(NN)]=62.4 to 200 GeV

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<p(T)<4.5 GeV/c, in a pseudorapidity range of 0.2<eta<1.4. The nuclear modification factor R(AA) is calculated relative to p+p data at the same collision energy as a function of collision centrality. For 2<p(T)<4.5 GeV/c, R(AA) is found to be significantly larger than in Au+Au collisions at sqrt[s(NN)]= 130 and 200 GeV. In contrast to the large change in R(AA), we observe a very similar centrality evolution of the p(T) spectra at sqrt[s(NN)]=62.4 and 200 GeV. The dynamical origin of this surprising factorization of energy and centrality dependence of particle production in heavy-ion collisions remains to be understood.

Pseudorapidity distribution of charged particles in d+Au collisions at sqrt[sNN]=200 GeV

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 <dN(ch)/d eta>|eta|< or =0.6)=9.4+/-0.7(syst) and the integrated primary charged particle multiplicity in the measured region is 82+/-6(syst). Estimates of the total charged particle production, based on extrapolations outside the measured pseudorapidity region, are also presented. The pseudorapidity distribution, normalized to the number of participants in d+Au collisions, is compared to those of Au+Au and p+(-)p systems at the same energy. The d+Au distribution is also compared to the predictions of the parton saturation model, as well as microscopic models.

Spatial and temporal factors during processing of audiovisual speech: a PET study

Speech perception can use not only auditory signals, but also visual information from seeing the speaker's mouth. The relative timing and relative location of auditory and visual inputs are both known to influence crossmodal integration psychologically, but previous imaging studies of audiovisual speech focused primarily on just temporal aspects. Here we used Positron Emission Tomography (PET) during audiovisual speech processing to study how temporal and spatial factors might jointly affect brain activations. In agreement with previous work, synchronous versus asynchronous audiovisual speech yielded increased activity in multisensory association areas (e.g., superior temporal sulcus [STS]), plus in some unimodal visual areas. Our orthogonal manipulation of relative stimulus position (auditory and visual stimuli presented at same location vs. opposite sides) and stimulus synchrony showed that (i) ventral occipital areas and superior temporal sulcus were unaffected by relative location; (ii) lateral and dorsal occipital areas were selectively activated for synchronous bimodal stimulation at the same external location; (iii) right inferior parietal lobule was activated for synchronous auditory and visual stimuli at different locations, that is, in the condition classically associated with the 'ventriloquism effect' (shift of perceived auditory position toward the visual location). Thus, different brain regions are involved in different aspects of audiovisual integration. While ventral areas appear more affected by audiovisual synchrony (which can influence speech identification), more dorsal areas appear to be associated with spatial multisensory interactions.

Centrality dependence of charged-hadron transverse-momentum spectra in d+Au collisions at sqrt[s(NN)]=200 GeV

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<p(T)<6.0 GeV/c, in a pseudorapidity range of 0.2<eta<1.4 in the deuteron direction. The evolution of the spectra with collision centrality is presented in comparison to p+pmacr; collisions at the same collision energy. With increasing centrality, the yield at high transverse momenta increases more rapidly than the overall particle density, leading to a strong modification of the spectral shape. This change in spectral shape is qualitatively different from observations in Au+Au collisions at the same energy. The results provide important information for discriminating between different models for the suppression of high-p(T) hadrons observed in Au+Au collisions.

Significance of the fragmentation region in ultrarelativistic heavy-ion collisions

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.