Effects of jet quenching on the hydrodynamical evolution of quark-gluon plasma.

We study the effects of jet quenching on the hydrodynamical evolution of the quark-gluon plasma (QGP) fluid created in a heavy-ion collision. In jet quenching, a hard QCD parton, before fragmenting into a jet of hadrons, deposits a fraction of its energy in the medium, leading to suppressed production of high-pT hadrons. Assuming that the deposited energy quickly thermalizes, we simulate the subsequent hydrodynamic evolution of the QGP fluid. For partons moving at supersonic speed, vp>cs, and sufficiently large energy loss, a shock wave forms leading to conical flow. The PHENIX Collaboration recently suggested that observed structures in the azimuthal angle distribution might be caused by conical flow. We show here that, for phenomenologically acceptable values of parton energy loss, conical flow effects are too weak to explain these structures.

Anti-inflammatory activity of Indian black tea (Sikkim variety).

In this study, the anti-inflammatory (in reference to the cardinal signs of inflammation) and other related pharmacological activities of the hot water extract of black tea (Camellia sinensis, Sikkim variety) were evaluated along with certain standard drugs. The extract showed significant inhibitory activity against carrageenin, histamine, serotonin and prostaglandin-induced pedal inflammation. The extract inhibited exudative inflammation. The tea extract also inhibited cotton pellet-induced granuloma formation and adjuvant-induced polyarthritis. Black tea extract showed significant inhibition against glucose oxidase-mediated inflammation. The present observations establish the efficacy of this particular variety of black tea, both in the exudative and proliferative forms and as well in the chronic phase of inflammation.

Psychopharmacological studies on Tragia involucrata root extract.

The methanol fraction of the root extract of Tragia involucrata was investigated for psychopharmacological activity in rodents. It produced an alteration of behavioural pattern and a reduction in spontaneous motility. A significant potentiation of pentobarbitone-induced sleep, a decrease of body temperature, suppression of the aggressive behaviour pattern and of the conditioned avoidance response (CAR) were observed with the fraction. These suggest that the methanol fraction of the T. involucrata root extract possesses significant central nervous system depressant action.

Antioxidant activity of the methanol fraction of Pluchea indica root extract.

Studies were carried out to evaluate the influence of the methanol fraction of Pluchea indica Less root extract (PIRE), the dual inhibitors (BW 755C and phenidone) and vitamin on both in vivo and in vitro free radical-scavenging activities, CCl(4)-induced lipid peroxidation and the metabolism of arachidonic acid by lipoxygenase. PIRE produced significant antiinflammatory activity against glucose oxidase-induced paw oedema (in vivo), inhibited hydroxyl radical and superoxide generation, lysis of erythrocytes induced by hydrogen peroxide, CCl(4)-induced lipid peroxidation and also dioxygenase activity of lipoxygenase (both in the presence and absence of hydrogen peroxide). Significantly higher free radical-scavenging activity was observed with BW 755C and phenidone compared with PIRE. However, both BW 755C and phenidone stimulated hydroxyl radical generation compared with the observed inhibitory effects of PIRE and vitamin E.

J/psi suppression in Pb + Pb collisions: a conventional description.

We have analyzed the latest NA50 data on J/psi suppression in Pb + Pb collisions. J/psi production is assumed to be a two-step process: (i) formation of a cc- pair, which is accurately calculable in QCD, and (ii) formation of a J/psi meson from the cc- pair, which can be conveniently parametrized. The parameters of the model were fixed from experimental data on the total J/psi cross section as a function of effective nuclear length. The model gives an excellent description of NA50 data on the ET dependence of the J/psi-to-Drell-Yan ratio. It was applied to the ET dependence of J/psi at RHIC energies, and predicts a much larger suppression of J/psi, in agreement with other model calculations.

Effect of amitriptyline on gastric ulceration.

Amitriptyline significantly inhibited alcohol, aspirin, indomethacin and cold-restraint stress-induced ulceration. Secretory studies conducted in pyloric-ligated rats revealed that the drug, at the doses employed, significantly reduced total acidity and protein content. However, significant reductions of the gastric volume were only observed at the highest dose of the drug. In another set of experiments, when 50% alcohol (v/v) was administered to the pyloric-ligated rats pretreated with amitriptyline, it was observed that the drug significantly reduced the pH, total acidity and protein content.

The central Scotland Escherichia coli O157:H7 outbreak: risk factors for the hemolytic uremic syndrome and death among hospitalized patients.

Little is known about risk factors for complications of Escherichia coli O157:H7 infection in adults. The 1996 outbreak in central Scotland involved the largest number of adult case patients in whom hemolytic uremic syndrome (HUS) developed and, ultimately, the largest number of deaths associated with E. coli O157:H7 infection that has yet been recorded. We investigated risk factors for HUS in a retrospective study of all hospitalized case patients in this outbreak. Of 120 case patients, 34 had HUS develop, 28 of whom were adults. Sixteen adults died. Significant risk factors for HUS were age <15 years or >65 years (odds ratio [OR], 4.4; 95% confidence interval [CI], 1.3-14.4), hypochlorhydria (OR, 6.7; 95% CI, 1.9-24.0), and coincidental antibiotics (OR, 4.7; 95% CI 1.4-16.5). Factors associated with HUS were as follows: white blood cell count >20 x 10(9) cells/L (OR, 8.25; 95% CI, 1.1-60.3), neutrophil count >15 x 10(9) cells/L (OR, 8.5; 95% CI, 1.5-50.1), and serum albumin level <35 g/L (OR, 7.2; 95% CI, 1.2-42.5) < or =3 days after symptom onset. Deaths were confined to case patients >65 years of age. Early identification of risk factors for HUS is vital and could select case patients for trials of preventative and treatment therapies.

Preliminary studies on the anti-inflammatory and analgesic activity of the methanolic fraction of the root extract of Tragia involucrata Linn.

Tragia involucrata has been widely used in the traditional medicinal system for the treatment of a variety of diseases. The effect of methanolic extract of T. involucrata was studied in different experimental animal models and it was revealed that the extract possesses significant analgesic and anti-inflammatory activity.

Effect of dothiepin on gastric ulceration mediated by lipid derived eicosanoids.

Dothiepin, a tricyclic antidepressant, significantly inhibited the development of gastric ulcers induced by alcohol, aspirin, indomethacin and Shay's pyloric ligation. Antisecretory studies in pyloric ligated rats revealed that the drug at a dose of 100 mg/kg significantly reduced total acidity, gastric output and protein content. In another set of experiments, dothiepin significantly reduced gastric output, total acidity and protein content in pyloric ligated rats which received 50% alcohol (v/v) 30 minutes after the administration of dothiepin.

Temperature dependent luminescence characteristics of Sm3+-doped silicate glass.

We report here on the optical characterisation of Sm3+ (5 wt%): SiO2 + Al2O3 + Li2O + Na2O + MgO glass from the measurements of optical absorption spectra (at 300 K), total luminescence spectra (10-300 K) and fluorescence lifetimes (10-300 K) of the prominent emission transitions of the Sm3+ ions. Besides its spectral properties, physical and nonlinearity characterising property parameters have also been computed to understand the optical dispersive power of this glass. By the application of Judd-Ofelt parameters (omega(lambda)) of the measured absorption spectrum, the radiative transition probability factors (A) and stimulated emission cross-section (sigma(p)E) of the observed fluorescent levels have been analysed. Both emission intensity and measured lifetimes of the prominent luminescent transition (4G(5/2) --> 6H(7/2)) concerning Sm3+-glass has been showing a descending trend with the rise in temperature with N2-laser (337.1 nm) as the source of excitation.

Neuropsychopharmacological profile of the methanolic fraction of Bryophyllum pinnatum leaf extract.

Neuropharmacological studies were conducted in experimental animals (rats and mice) with the methanolic fraction of Bryophyllum pinnatum leaf extract. The fraction produced alteration of behaviour pattern, caused dose-dependent potentiation of pentobarbitone sleeping time and had significant analgesic activity. Significant reduction of exploratory behaviour and loss of residual curiosity were among the effects observed with the fraction. The observations suggest that the methanolic fraction of Bryophyllum pinnatum possesses a potent CNS depressant action.

Studies on the possible mechanism of the gastric mucosal protection by Calotropis procera--involvement of 5-lipoxygenase pathway.

The role of chloroform fraction of Calotropis procera root extract on different experimental ulcer models in rats was investigated. The extract demonstrated significant anti-ulcer activity against aspirin, indomethacin, ethanol, indomethacin + ethanol, or stress-induced ulcerations. Significant inhibition of gastric secretory volume and total acidity in pylorus ligated rats were observed to occur with the extract. It was also observed that the root extract significantly inhibited arachidonic acid metabolism induced by soyabean lipoxygenase. The results suggest that the anti-ulcer activity of the extract might be attributable to the inhibition of 5-lipoxygenase (5-LO).

Microtags with 150-nm line gratings fabricated by use of extreme-ultraviolet lithography.

The microtag concept is an anticounterfeiting and security measure. Microtags are computer-generated holograms (CGH's) consisting of 150-nm lines arranged to form 300-nm-period gratings. The microtags that we describe were designed for readout at 442nm . The smallest microtag measures 56micromx80 microm when viewed at normal incidence. The CGH design process uses a modified iterative Fourier-transform algorithm to create either phase-only or phase-and-amplitude microtags. We also report on a simple and compact readout system for recording the diffraction pattern formed by a microtag. The measured diffraction patterns agree very well with predictions.

Bacterial meningitis--the importance of cerebro-spinal fluid examination.

The role of lumbar puncture in bacterial meningitis has been debated in recent years, especially in the presence of worsening headache, alteration of conscious level, focal neurological signs, papilloedema or a haemorrhagic rash. However valuable bacteriological and epidemiological information will be lost if lumbar puncture is avoided, despite blood cultures being taken. This loss of information will be highlighted if pre-admission antibiotics are administered (this should now be standard practice).

Mass-producible microscopic computer-generated holograms: microtags.

We have developed a method for encoding phase and amplitude in microscopic computer-generated holograms (microtags) for security applications. An 8 x 8 cell phase-only and an 8 x 8 cell phase-and-amplitude microtag design has been exposed in photoresist by the extreme-ultraviolet (13.4-nm) lithography tool developed at Sandia National Laboratories. Each microtag measures 80 microm x 160 microm and contains features that are 0.2 microm wide. Fraunhofer zone diffraction patterns can be obtained from fabricated microtags without any intervening optics and compare favorably with predicted diffraction patterns.

A severe outbreak of E. coli O157 in two psychogeriatric wards.

In October 1990 there was a severe outbreak of Escherichia coli O157 in two psychogeriatric wards of a large psychiatric hospital in Lanarkshire. There were 11 cases (eight patients and three staff), of whom four died (all patients). Two cases, one staff and one patient (the likely index case) were identified serologically after the outbreak was over. E. coli O157 was not cultured from any food, water or milk samples, and the evidence suggests that the index case had eaten food brought into the hospital. The results also suggest that the incubation period of the organism may be longer than is currently recognized, particularly for person-to-person spread. A Fatal Accident Inquiry was held into the deaths, and the Sheriff's Determination is discussed together with the implications of the results for infection control procedures.

Infection control in hospitals: has its quality-enhancing and cost-effective role been appreciated?

A review of data from surveys worldwide, including the United Kingdom and the United States, or morbidity and mortality and costs incurred as direct consequences of hospital-acquired infection is presented. These data testify to the role of hitherto somewhat undervalued Infection Control in hospitals as a key factor in the quality of medical care and also establish its contribution towards cost-effectiveness in various health care systems, including the National Health Service in the UK (NHS). It is appropriate, therefore, for Infection Control to be accorded proper appreciation and adequate funding. The achievement of these aims is likely to be helped by the recent changes in the NHS management system and supported by the requirements of Medical Audit and Hospital Accreditation Schemes.

Isolation of a toxin from jellyfish Acromitus rabanchatu and its effect on skeletal muscle.

A toxin (T-Ar) from the crude extract of jellyfish Acromitus rabanchatu was purified by (NH4)2SO4 fractionation followed by ion-exchange chromatography on DEAE-cellulose column. The mol. wt of T-Ar was found to be about 182,000. T-Ar reversibly blocked the twitch response of rat diaphragm muscle stimulated either indirectly or directly. It also reversibly blocked the twitch responses of chick biventer-cervicis muscle preparations. T-Ar failed to alter the contractures of the denervated rat diaphragm muscle preparation induced by acetylcholine, potassium chloride and caffeine. Similarly, acetylcholine and carbachol-induced contractures on chick biventer-cervicis muscle preparation were not influenced by T-Ar. The T-Ar-induced blockade of twitch responses of rat phrenic nerve-diaphragm was enhanced in high Na+ or low Ca2+ medium, and reduced in low Na+ or high Ca(2+)-containing medium. The results suggest that the toxin (T-Ar) possesses a direct paralysing effect on the muscle membrane.