572 research outputs found

    Seismic performance of ductility classes medium RC beam-column connections with continuous rectangular spiral transverse reinforcements

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    The seismic performance of RC columns can considerably be improved through the use of continuous spiral reinforcement in terms of ductility and energy dissipation capacity. Since the beam-column connections were subjected to brittle failure after earthquakes, the simultaneous application of this method in both beams and columns could greatly improve the seismic behaviour of such connections. In this investigation, a new proposed detail for beam to column connection introduced as "twisted opposing rectangular spiral" was investigated both experimentally and numerically and its seismic performance was verified through comparison with normal rectangular spiral and conventional shear reinforcement systems. In this research, three full scale beam to column connections were first designed according to Eurocode (EC8-04) for Medium ductility classes and then tested by quasi-static cyclic loading suggested by ACI Building Code (ACI 318-08). Finally, numerical methods were hired to validate the experimental results. The results indicated that the ultimate lateral resistance, ductility and energy dissipation capacity of the connection could be improved using the new proposed connection

    Hepatic transaminase and alkaline phosphatase enzyme levels in HIV/HBV co‑infected and HIV mono‑infected patients in Maiduguri, Nigeria

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    Background: Studies have shown that HIV‑HBV co‑infected patients have an increased risk of liver‑related morbidity and mortality compared to their HIV‑mono‑infected counterparts. Furthermore, it has been reported that HIV‑HBV co‑infected patients have a significantly high incidence of drug‑induced hepatotoxicity following commencement of HAART than HIV‑mono‑infected patients.Objectives: To compare the levels of aspartate amino transferase (AST), alanine amino transferase (ALT) and alkaline phosphatase (ALKPO4) enzyme levels between HAART naïve HIV‑HBV co‑infected patients and their HIV‑mono‑infected counterparts.Materials and Methods: A cross‑sectional descriptive study in which 142 newly diagnosed HIV/HBV co‑infected and HIV mono‑infected adults were investigated for alkaline aminotransferase, aspartate aminotransferase and alkaline phosphatase enzyme levels.Results: The study subjects comprised of 80 (56.3%) females and 62 (46.7%) males. The age range of the study population was 15‑65 years. The mean ages of male and female subjects were 45.5 ± 10.5 years and 39.1 ± 7.5 years respectively (P < 0.05). Sixty‑three (44.4%) study subjects were HIV/HBV co‑infected while 79 (55.6%) were HIV mono‑infected. The mean ALT enzyme level of HIV/HBV co‑infected subjects was significantly higher than that of HIV mono‑infected ones i.e., 42.12 IU/l vs. 27.86 IU/l, (P = 0.038). However, there was no statistically significant difference in the mean AST (30.14 IU/l vs. 29.09 IU/l, P = 0.893) and ALKPO4 (55.86 IU/l vs. 60.97 IU/l, P = 0.205) enzyme levels between HIV‑HBV co‑infected and HIV mono‑infected subjects albeit the two enzymes were moderately elevated in both categories of subjects.Conclusion: The significantly elevated ALT enzyme levels amongst HIV‑HBV co‑infected subjects suggest that HIV‑HBV co‑infected patients may have an increased risk of liver‑related morbidity and mortality than their HIV mono‑infected counterparts. Screening for serological markers of chronic HBV infection, as well as hepatic transaminase enzyme levels in all newly diagnosed HIV‑positive patients is therefore recommended before commencement of HAART.Keywords: Alkaline phosphatase enzyme, hepatitis B virus surface antigen, hepatic transaminase enzymes, human immunodeficiency virusNigerian Journal of Clinical Practice • Oct-Dec 2013 • Vol 16 • Issue

    Frontonasal dysplasia Sequence : A case report

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    Frontonasal dysplasia (FND) is a very rare congenital abnormality in which the mid face does not develop normally. It affects mainly the head and face. Cause is unknown but may be sporadic or familial. We report a rare case of a full term baby who presented with classical features of FND in Maiduguri, Nigeria. Management difficulty in resource limited setting is highlighted.Key words: Dysmorphism, Frontonasaldysplasia, Neonate

    The state of ambient air quality in Pakistan—a review

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    Background and purpose: Pakistan, during the last decade, has seen an extensive escalation in population growth, urbanization, and industrialization, together with a great increase in motorization and energy use. As a result, a substantial rise has taken place in the types and number of emission sources of various air pollutants. However, due to the lack of air quality management capabilities, the country is suffering from deterioration of air quality. Evidence from various governmental organizations and international bodies has indicated that air pollution is a significant risk to the environment, quality of life, and health of the population. The Government has taken positive steps toward air quality management in the form of the Pakistan Clean Air Program and has recently established a small number of continuous monitoring stations. However, ambient air quality standards have not yet been established. This paper reviews the data being available on the criteria air pollutants: particulate matter (PM), sulfur dioxide, ozone, carbon monoxide, nitrogen dioxide, and lead. Methods: Air pollution studies in Pakistan published in both scientific journals and by the Government have been reviewed and the reported concentrations of PM, SO2, O3, CO, NO2, and Pb collated. A comparison of the levels of these air pollutants with the World Health Organization air quality guidelines was carried out. Results: Particulate matter was the most serious air pollutant in the country. NO2 has emerged as the second high-risk pollutant. The reported levels of PM, SO2, CO, NO2, and Pb were many times higher than the World Health Organization air quality guidelines. Only O3 concentrations were below the guidelines. Conclusions: The current state of air quality calls for immediate action to tackle the poor air quality. The establishment of ambient air quality standards, an extension of the continuous monitoring sites, and the development of emission control strategies are essential. © Springer-Verlag 2009

    Shear capacity evaluation of reinforced concrete beams: finite element simulation

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    The shear performance of reinforced concrete beams with rectangle cross-section and two different continuous rectangular spiral shear reinforcement under monotonous loading is numerically evaluated. Further, the behaviour of two continuous shear reinforcement systems named, “Single Square Spring Shear Resistance System” (SSSSRS) and “Double Square Spring Shear Resistance System” (DSSSRS) as transverse reinforcements are compared with conventional discontinuous system “Stirrups”. The finite element study includes three (3) beams. The results clearly show that the application of continuous shear reinforcement system delivered improved shear behaviour and enhanced bearing capacity in beams. Beams with Single Square Spring Shear Resistance System (SSSSRS) and Double Square Spring Shear Resistance System (DSSSRS) exhibited 14.4% and 19.8% increased shear performance in comparison with conventional control beam. It was concluded that under the same deflection higher forces was achieved for “Single Square Spring Shear Resistance System” (SSSSRS) and “Double Square Spring Shear Resistance System” (DSSSRS) compared to control specimens

    Improved functionalization of oleic acid-coated iron oxide nanoparticles for biomedical applications

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    Superparamagnetic iron oxide nanoparticles can providemultiple benefits for biomedical applications in aqueous environments such asmagnetic separation or magnetic resonance imaging. To increase the colloidal stability and allow subsequent reactions, the introduction of hydrophilic functional groups onto the particles’ surface is essential. During this process, the original coating is exchanged by preferably covalently bonded ligands such as trialkoxysilanes. The duration of the silane exchange reaction, which commonly takes more than 24 h, is an important drawback for this approach. In this paper, we present a novel method, which introduces ultrasonication as an energy source to dramatically accelerate this process, resulting in high-quality waterdispersible nanoparticles around 10 nmin size. To prove the generic character, different functional groups were introduced on the surface including polyethylene glycol chains, carboxylic acid, amine, and thiol groups. Their colloidal stability in various aqueous buffer solutions as well as human plasma and serum was investigated to allow implementation in biomedical and sensing applications.status: publishe

    Functional kinomics establishes a critical node of volume-sensitive cation-Cl<sup>-</sup> cotransporter regulation in the mammalian brain

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    This is the final version of the article. Available from the publisher via the DOI in this record.There is another record in ORE for this publication: http://hdl.handle.net/10871/33424Cell volume homeostasis requires the dynamically regulated transport of ions across the plasmalemma. While the ensemble of ion transport proteins involved in cell volume regulation is well established, the molecular coordinators of their activities remain poorly characterized. We utilized a functional kinomics approach including a kinome-wide siRNA-phosphoproteomic screen, a high-content kinase inhibitor screen, and a kinase trapping-Orbitrap mass spectroscopy screen to systematically identify essential kinase regulators of KCC3 Thr991/Thr1048 phosphorylation – a key signaling event in cell swelling-induced regulatory volume decrease (RVD). In the mammalian brain, we found the Cl−-sensitive WNK3-SPAK kinase complex, required for cell shrinkage-induced regulatory volume decrease (RVI) via the stimulatory phosphorylation of NKCC1 (Thr203/Thr207/Thr212), is also essential for the inhibitory phosphorylation of KCC3 (Thr991/Thr1048). This is mediated in vivo by an interaction between the CCT domain in SPAK and RFXV/I domains in WNK3 and NKCC1/KCC3. Accordingly, genetic or pharmacologic WNK3-SPAK inhibition prevents cell swelling in response to osmotic stress and ameliorates post-ischemic brain swelling through a simultaneous inhibition of NKCC1-mediated Cl− uptake and stimulation of KCC3-mediated Cl− extrusion. We conclude that WNK3-SPAK is an integral component of the long-sought “Cl−/volume-sensitive kinase” of the cation-Cl− cotransporters, and functions as a molecular rheostat of cell volume in the mammalian brain.We thank the excellent technical support of the MRC-Protein Phosphorylation and Ubiquitylation Unit (PPU) DNA Sequencing Service (coordinated by Nicholas Helps), the MRC-PPU tissue culture team (coordinated by Laura Fin), the Division of Signal Transduction Therapy (DSTT) antibody purification teams (coordinated by Hilary McLauchlan and James Hastie). We are grateful to the MRC PPU Proteomics facility (coordinated by David Campbell, Robert Gourlay and Joby Varghese). We thank for support the Medical Research Council (MC_UU_12016/2; DRA) and the pharmaceutical companies supporting the Division of Signal Transduction Therapy Unit (AstraZeneca, Boehringer-Ingelheim, GlaxoSmithKline, Merck KGaA, Janssen Pharmaceutica and Pfizer; DRA). We thank Thomas J. Jentsch (Max-Delbrück-Centrum für Molekulare Medizin) for providing the KCC1/3 double KO mice and his reading of this manuscript. We thank Nathaniel Grey (Harvard) for providing the kinase inhibitor library used in this study (NIH LINCS Program grant U54HL127365). This work was also supported by a Harvard-MIT Neuroscience Grant (to KTK/SJE)

    Seroprevalence of IgG anti- T. Gondii antibody among HIV-infected patients in Maiduguri, north eastern Nigeria.

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    Background: Toxoplasma gondii infection is one of the commonest opportunistic infections in HIV-infected patients, with the fatal consequences of toxoplasmic encephalitis particularly in advanced disease. However, data regarding T.gondii infection in the setting of HIV/AIDS are scant in Nigeria. Objective: To determine the seroprevalence of T.gondii amongst HIV-infected patients as well as to determine the correlation between anti-T.gondii IgG titre and the CD4+ cell count/HIV-1 RNA viral load. Method: A cross sectional study in which a total of 190 subjects were involved i.e. 110 newly diagnosed HAART naïve HIV-positive patients and 80 apparently healthy HIV-negative age- and-sex matched controls that were selected by simple random sampling method. Results: The age range of the study population was 20-64 years. The mean ages of male subjects for both HIV-positives and controls were 37.52 ±8.20 years and 35.79 ±12.31years, respectively, (p= 0.462). On the other hand, the mean ages of female subjects for both HIV-positives and controls were 29.90 ±6.98 years and 32.30 ±10.29 years, respectively, (p=0.149). Twenty one subjects (19.1%) among HIV-positives and 1 (1.25%) HIV-negative tested positive for anti-T.gondii IgG, respectively, (p= 0.000). The prevalence rate ration of anti-T. gondii IgG of HIV positives compared to HIVnegatives was 15.28. Significant proportion of anti-T.gondii positive subjects presented with AIDS defining illnesses compared with their anti-T.gondii negative counterparts. Conclusion:The study has shown that anti-T.gondii IgG is about 15 times more prevalent among HIV positive patients compared to controls. Routine screening for T.gondii IgG anti-body is therefore recommended for all HIV-infected subjects at the facility as well as commencement of chemoprophylaxis against Toxoplasmic encephalitis in HIV-infected patients with CD4+ cell count of &lt;100 cells/ml

    Recruitment in the sea: bacterial genes required for inducing larval settlement in a polychaete worm

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    Metamorphically competent larvae of the marine tubeworm Hydroides elegans can be induced to metamorphose by biofilms of the bacterium Pseudoalteromonas luteoviolacea strain HI1. Mutational analysis was used to identify four genes that are necessary for metamorphic induction and encode functions that may be related to cell adhesion and bacterial secretion systems. No major differences in biofilm characteristics, such as biofilm cell density, thickness, biomass and EPS biomass, were seen between biofilms composed of P. luteoviolacea (HI1) and mutants lacking one of the four genes. The analysis indicates that factors other than those relating to physical characteristics of biofilms are critical to the inductive capacity of P. luteoviolacea (HI1), and that essential inductive molecular components are missing in the non-inductive deletion-mutant strains

    Obatoclax induces Atg7-dependent autophagy independent of beclin-1 and BAX/BAK

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    Direct pharmacological targeting of the anti-apoptotic B-cell lymphoma-2 (BCL-2) family is an attractive therapeutic strategy for treating cancer. Obatoclax is a pan-BCL-2 family inhibitor currently in clinical development. Here we show that, although obatoclax can induce mitochondrial apoptosis dependent on BCL-2 associated x protein/BCL-2 antagonist killer (BAX/BAK) consistent with its on-target pharmacodynamics, simultaneous silencing of both BAX and BAK did not abolish acute toxicity or loss of clonogenicity. This is despite complete inhibition of apoptosis. Obatoclax dramatically reduced viability without inducing loss of plasma membrane integrity. This was associated with rapid processing of light chain-3 (LC3) and reduction of S6 kinase phosphorylation, consistent with autophagy. Dramatic ultrastructural vacuolation, not typical of autophagy, was also induced. Silencing of beclin-1 failed to prevent LC3 processing, whereas knockout of autophagy-related (Atg)7 abolished LC3 processing but failed to prevent obatoclax-induced loss of clonogenicity or ultrastructural changes. siRNA silencing of Atg7 in BAX/BAK knockout mouse embryonic fibroblasts did not prevent obatoclax-induced loss of viability. Cells selected for obatoclax resistance evaded apoptosis independent of changes in BCL-2 family expression and displayed reduced LC3 processing. In summary, obatoclax exhibits BAX- and BAK-dependent and -independent mechanisms of toxicity and activation of autophagy. Mechanisms other than autophagy and apoptosis are blocked in obatoclax resistant cells and contribute significantly to obatoclax's anticancer efficacy
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