A biofilm reactor was developed to investigate the sorption of polycyclic aromatic hydrocarbons (PAH) as model compounds for hydrophobic organic contaminants (HOC) to intact microbial biofilms at ...environmentally realistic concentrations. When operated as a differential column batch reactor, the system can be used to study the thermodynamics as well as the kinetics of the exchange of HOC between an aqueous phase and microbial biofilms. Organic carbon normalized partition coefficients (
K
oc) for phenanthrene, fluoranthene and pyrene were at the lower end of those known for other organic sorbents. Intra-biofilm diffusion coefficients (
D) were calculated from decrease in solute concentration over time using a model for diffusion through a plane sheet and ranged from 0.23 to 0.45×10
−9
cm
2
s
−1 for the three PAH. These diffusion coefficients are about four orders of magnitude lower than those reported in literature for free aqueous solution. These data and the experimental approach presented here are useful to assess the importance of microbial biofilms for exchange processes of HOC in heterogeneous systems such as water distribution systems, membranes and aquifers, sewer systems or surface soils.
Previous studies showed that angiotensin II (AII) infusion increased survival in gerbils subjected to abrupt unilateral carotid ligation. Recently, stimulation of the AII AT2 receptor, reportedly ...effectively extended the blood pressure (BP) range of cerebral blood flow (CBF) autoregulation. We evaluated the survival of gerbils treated with PD-123319, a ligand of AT2 receptors, to test the hypothesis that restoration of BF to ischemic cerebral tissue produced by AII is mediated through AT2 receptors. Abrupt unilateral carotid ligation was performed on 300 gerbils. In five experimental groups, animals received no drug pretreatment(a) saline; (b)-(d) PD-123319 1.0, 3.0, and 10 mg/kg; and (e) losartan 10 mg/kg. In three additional experimental groups, animals were pretreated with enalaprilat(f) saline; (g) PD-123319, 10 mg/kg, and (h) losartan, 10 mg/kg. Survival for 48 h was significantly improved by PD-123319 (10 mg/kg) (p < 0.05) and by losartan (10 mg/kg) (p < 0.05) as compared with animals injected with saline. Pretreatment with enalaprilat neutralized the protective effect of losartan. PD-123319 is an AT2 agonist and improved survival in this animal model of stroke. Losartan, an AT1 antagonist, also improved survival, possibly through renin release and AT2 stimulation by endogenous AII. This effect was neutralized by enalaprilat.
Abstract Purpose Bulb syringes can be used for the self-clearance of earwax and, in the short term, appear effective. We compared the long-term effectiveness of self-irrigation using a bulb syringe ...with routine care in United Kingdom (UK) family practice clinics where irrigating ears to remove wax is a common procedure. Methods We assessed the impact on health service utilization as a follow-up to a single-blind, randomized, controlled trial of 237 patients attending 7 UK family practice clinics with symptomatic, occluding earwax who were randomized to an intervention group (ear drops, bulb syringe, instructions on its use and re-use) or a control group (ear drops, then clinic irrigation). After 2 years, a retrospective notes search for earwax-related consultations was carried out. We used an intention-to-treat analysis to assess differences in dichotomous outcomes between groups. Results In the 2-year trial follow-up, more control group patients returned with episodes of earwax: 85 of 117 (73%) control vs 70 of 117 (60%) intervention, χ2 = 4.30; P = .038; risk ratio 1.21 (95% CI, 1.01–1.37). The numbers of consultations amounted to 1.15 (control) vs 0.64 (intervention) (incidence rate ratio 1.79; 95% CI, 1.05–3.04, P = .032), ie, a difference of 0.50 consultations, thus saving a consultation on average for every 2 people. Conclusion For patients who have not already tried bulb syringes, self-irrigation using a bulb syringe significantly reduces subsequent demand for ear irrigation by health professionals. Advocating the initial use of bulb syringes could reduce demand for ear irrigation in family practice clinics.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
The production of single- and multi-photon events has been studied in the reaction e(+) e(-) --> gamma(gamma) + invisible particles. The data collected with the DELPHI detector during the years 1999 ...and 2000 at centre-of-mass energies between 191 GeV and 209 GeV was combined with earlier data to search for phenomena beyond the Standard Model. The measured number of light neutrino families was consistent with three and the absence of an excess of events beyond that predicted by the Standard Model processes was used to set limits on new physics. Both model-independent searches and searches for new processes predicted by supersymmetric and extra-dimensional models have been made. Limits on new non-standard model interactions between neutrinos and electrons were also determined.
The heaviest known Fermion particle—the top quark—was discovered at Fermilab in the first run of the Tevatron in 1995. However, besides its mere existence one needs to study its properties precisely ...in order to verify or falsify the predictions of the Standard Model. With the top quark's extremely high mass and short lifetime such measurements probe yet unexplored regions of the theory and bring us closer to solving the open fundamental questions of our universe of elementary particles such as why three families of quarks and leptons exist and why their masses differ so dramatically. To perform these measurements hundreds of millions of recorded proton-antiproton collisions must be reconstructed and filtered to extract the few top quarks produced. Simulated background and signal events with full detector response need to be generated and reconstructed to validate and understand the results. Since the start of the second run of the Tevatron the DØ collaboration has brought Grid computing to its aid for the production of simulated events. Data processing on the Grid has recently been added and thereby enabled us to effectively triple the amount of data available with the highest quality reconstruction methods. We will present recent top quark results DØ obtained from these improved data and explain how they benefited from the availability of computing resources on the Grid.
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