845 research outputs found

    Enhanced roughness of lipid membranes caused by external electric fields

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    The behavior of lipid membranes in the presence of an external electric field is studied and used to examine the influence of such fields on membrane parameters such as roughness and show that for a micro sized membrane, roughness grows as the field increases. The dependence of bending rigidity on the electric field is also studied and an estimation of thickness of the accumulated charges around lipid membranes in a free-salt solution is presented.Comment: 9 pages, 6 figures, to appear in Computational Materials Scienc

    Surgical Indications for Eye Removal in Enugu, South Eastern Nigeria

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    Objective: To determine the surgical indications for removal of the eye in Enugu in south eastern Nigeria. Method: Retrospective case series review. Results: At the University of Nigeria Teaching Hospital Enugu, between 1st January 1994 and 31st December 2003, 106 eyes of 106 patients, comprising 71 (67.0%) males and 35 (33.0%) females, aged 6-72 years (mean 31.8), were removed by evisceration (59; 55.7%), enucleation (35; 33.0%), and exenteration (12; 11.3%). Severe open globe injury (49; 46.2%), infection (29; 27.4%), malignant tumour (15; 14.2%) and blind painful eye (14; 13.2%) were the indications for eye removal. Eye removal was more frequent in males (67.0%), among farmers (21.7%), and among the 21-40 year age group (41.5%). Patients who had their eyes removed constituted 0.42% of new outpatients, 4.63% of inpatients and 7.83% of patients who had eye operations during the study period. Conclusion: The indications for eye removal were mainly for preventable/curable causes. There is, therefore, a need to improve promotive, preventive and curative eye care delivery to reverse this trend. Keywords:eye, removal, indications, Enugu, NigeriaNigerian Journal of Opthalmology Vol. 15 (2) 2007: pp. 44-4

    Effect of Yangtze River on population genetic structure of the relict plant Parrotia subaequalis in eastern Chin

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    Parrotia subaequalis (Hamamelidaceae) is a Tertiary relic species endemic in eastern China. We used inter-simple sequence repeat (ISSR) markers to access genetic diversity and population genetic structure in natural five populations of P. subaequalis. The levels of genetic diversity were higher at species level (H = 0.2031) but lower at population level (H = 0.1096). The higher genetic diversity at species levels might be attributed to the accumulation of distinctive genotypes which adapted to the different habitats after Quaternary glaciations. Meanwhile, founder effects on the early stage, and subsequent bottleneck of population regeneration due to its biological characteristics, environmental features, and human activities, seemed to explain the low population levels of genetic diversity. The hierarchical AMOVA revealed high levels (42.60%) of among-population genetic differentiation, which was in congruence with the high levels of Nei’s genetic differentiation index (GST = 0.4629) and limited gene flow (Nm = 0.5801) among the studied populations. Mantel test showed a significant isolation-by-distance, indicating that geographic isolation has a significant effect on genetic structure in this species. Unweighted pair-group method with arithmetic average clustering, PCoA, and Bayesian analyses uniformly recovered groups that matched the geographical distribution of this species. In particular, our results suggest that Yangtze River has served as a natural barrier to gene flow between populations occurred on both riversides. Concerning the management of P. subaequalis, the high genetic differentiation among populations indicates that preserving all five natural populations in situ and collecting enough individuals from these populations for ex situ conservation are necessary

    Search for new phenomena in final states with an energetic jet and large missing transverse momentum in pp collisions at √ s = 8 TeV with the ATLAS detector

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    Results of a search for new phenomena in final states with an energetic jet and large missing transverse momentum are reported. The search uses 20.3 fb−1 of √ s = 8 TeV data collected in 2012 with the ATLAS detector at the LHC. Events are required to have at least one jet with pT > 120 GeV and no leptons. Nine signal regions are considered with increasing missing transverse momentum requirements between Emiss T > 150 GeV and Emiss T > 700 GeV. Good agreement is observed between the number of events in data and Standard Model expectations. The results are translated into exclusion limits on models with either large extra spatial dimensions, pair production of weakly interacting dark matter candidates, or production of very light gravitinos in a gauge-mediated supersymmetric model. In addition, limits on the production of an invisibly decaying Higgs-like boson leading to similar topologies in the final state are presente

    Waste leachate induces histological alterations in Limicolaria aurora (Jay, 1839) digestive gland

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    360-367Unsanitary open dumping and burning of wastes in dumpsites results to constant leaching of waste pollutants into the surrounding environment with attendant harmful consequences on wildlife and public health. Here, we investigated the histological effects of Onitsha municipal waste leachate on the Giant African land snail, Limicolaria aurora (Jay 1839). The histopathological effects of waste leachate on the digestive cells of the snails were examined following standard protocols. Snails were exposed to different concentrations (0, 6.25, 12.5, 25.0 and 50.0%) of the leachate for a total duration of 21 days. Histological results obtained showed that waste leachate caused dose and duration dependent alterations in the digestive glands of L. aurora. Obvious histological variations were observed in snails exposed to 50% concentrations of the leachate compared to other doses. Observed histological changes were mainly degeneration of the digestive tubules, fragmentation and disappearance of the digestive cells, marked increase in excretory cells, necrosis and epithelia sloughing. This study therefore highlights the potential toxicity of waste leachate of causing mild to severe damage in the tissues of organisms. Reinforcing the fact, that waste leachate contains a mix of toxic substances that could pose a severe injury to the biological system of surrounding biota, including humans

    Endothelial dysfunction and diabetes: roles of hyperglycemia, impaired insulin signaling and obesity

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    Ustekinumab as Induction and Maintenance Therapy for Crohn’s Disease

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    BACKGROUND Ustekinumab, a monoclonal antibody to the p40 subunit of interleukin-12 and inter-leukin-23, was evaluated as an intravenous induction therapy in two populations with moderately to severely active Crohn’s disease. Ustekinumab was also evaluated as subcutaneous maintenance therapy. METHODS We randomly assigned patients to receive a single intravenous dose of ustekinumab (either 130 mg or approximately 6 mg per kilogram of body weight) or placebo in two induction trials. The UNITI-1 trial included 741 patients who met the criteria for primary or secondary nonresponse to tumor necrosis factor (TNF) antagonists or had unacceptable side effects. The UNITI-2 trial included 628 patients in whom conventional therapy failed or unacceptable side effects occurred. Patients who completed these induction trials then participated in IM-UNITI, in which the 397 patients who had a response to ustekinumab were randomly assigned to receive subcutaneous maintenance injections of 90 mg of ustekinumab (either every 8 weeks or every 12 weeks) or placebo. The primary end point for the induction trials was a clinical response at week 6 (defined as a decrease from baseline in the Crohn’s Disease Activity Index [CDAI] score of ≥100 points or a CDAI score <150). The primary end point for the maintenance trial was remission at week 44 (CDAI score <150). RESULTS The rates of response at week 6 among patients receiving intravenous ustekinumab at a dose of either 130 mg or approximately 6 mg per kilogram were significantly higher than the rates among patients receiving placebo (in UNITI-1, 34.3%, 33.7%, and 21.5%, respectively, with P≤0.003 for both comparisons with placebo; in UNITI-2, 51.7%, 55.5%, and 28.7%, respectively, with P<0.001 for both doses). In the groups receiving maintenance doses of ustekinumab every 8 weeks or every 12 weeks, 53.1% and 48.8%, respectively, were in remission at week 44, as compared with 35.9% of those receiving placebo (P = 0.005 and P = 0.04, respectively). Within each trial, adverse-event rates were similar among treatment groups. CONCLUSIONS Among patients with moderately to severely active Crohn’s disease, those receiving intravenous ustekinumab had a significantly higher rate of response than did those receiving placebo. Subcutaneous ustekinumab maintained remission in patients who had a clinical response to induction therapy. (Funded by Janssen Research and Development; ClinicalTrials.gov numbers, NCT01369329, NCT01369342, and NCT01369355.

    Study of hadronic event-shape variables in multijet final states in pp collisions at √s=7 TeV

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    Measurement of the t¯tZ and t¯tW cross sections in proton-proton collisions at √s=13 TeV with the ATLAS detector

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    A measurement of the associated production of a top-quark pair (t¯t) with a vector boson (W, Z) in proton-proton collisions at a center-of-mass energy of 13 TeV is presented, using 36.1  fb−1 of integrated luminosity collected by the ATLAS detector at the Large Hadron Collider. Events are selected in channels with two same- or opposite-sign leptons (electrons or muons), three leptons or four leptons, and each channel is further divided into multiple regions to maximize the sensitivity of the measurement. The t¯tZ and t¯tW production cross sections are simultaneously measured using a combined fit to all regions. The best-fit values of the production cross sections are σt¯tZ=0.95±0.08stat±0.10syst pb and σt¯tW=0.87±0.13stat±0.14syst pb in agreement with the Standard Model predictions. The measurement of the t¯tZ cross section is used to set constraints on effective field theory operators which modify the t¯tZ vertex

    Constraints on parton distribution functions and extraction of the strong coupling constant from the inclusive jet cross section in pp collisions at √s=7 TeV

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