552 research outputs found

    Effect of mixture proportions on the drying shrinkage and permeation properties of high strength concrete containing class F fly ash

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    Sustainability of concrete can be improved by using large volume of fly ash as a replacement of cement and by ensuring improved durability of concrete. Durability of concrete containing large volume of class F fly ash is dependent on the design of mixture proportions. This paper presents an experimental study on the effect of mixture proportions on the drying shrinkage and permeation properties of high strength concrete containing large volume local class F fly ash. Concrete mixtures were designed with and without adjustments in the water to binder ratio (w/b) and the total binder content to take into account the incorporation of fly ash up to 40% of total binder. Concretes, in which the mixture proportions were adjusted for fly ash inclusion achieved equivalent strength of the control concrete and showed enhanced properties of drying shrinkage, sorptivity, water permeability and chloride penetration as compared to the control concrete. The improvement of durability properties was less significant when no adjustments were made to the w/b ratio and total binder content. The results show the necessity of the adjustments in mixture proportions of concrete to achieve improved durability properties when using class F fly ash as a cement replacement

    The γδ variant of T cell large granular lymphocyte leukemia is very similar to the common αβ type: report of two cases

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    The vast majority of cases of T cell large granular lymphocyte (T-LGL) leukemia have a CD3+, CD4−, CD8+ phenotype and express the αβ T cell receptor. Whether the rare γδ variant should be included in the same diagnostic category is currently unclear. Two well-characterized cases of γδ T-LGL leukemia were identified by our laboratory in 2007. These two cases and other reports of γδ T-LGL leukemia were compared with the common αβ variant. Other than more often being negative for both CD4 and CD8 (in about 35% to 40% of cases), the γδ variant of T-LGL leukemia is similar to the common αβ type in virtually all respects and should be included in the general category of T-LGL leukemia. However, it is important to exclude other more aggressive γδ T cell lymphoproliferative disorders

    Spectrum and antibiotic sensitivity of bacteria contaminating the upper gut in patients with malabsorption syndrome from the tropics

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    BACKGROUND: Various causes of malabsorption syndrome (MAS) are associated with intestinal stasis that may cause small intestinal bacterial overgrowth (SIBO). Frequency, nature and antibiotic sensitivity of SIBO in patients with MAS are not well understood. METHODS: Jejunal aspirates of 50 consecutive patients with MAS were cultured for bacteria and colony counts and antibiotic sensitivity were performed. Twelve patients with irritable bowel syndrome were studied as controls. RESULTS: Culture revealed growth of bacteria in 34/50 (68%) patients with MAS and 3/12 controls (p < 0.05). Colony counts ranged from 3 × 10(2 )to 10(15 )(median 10(5)) in MAS and 100 to 1000 (median 700) CFU/ml in controls (p 0.003). 21/50 (42%) patients had counts ≥10(5 )CFU/ml in MAS and none of controls (p < 0.05). Aerobes were isolated in 34/34 and anaerobe in 1/34. Commonest Gram positive and negative bacteria were Streptococcus species and Escherichia coli respectively. The isolated bacteria were more often sensitive to quinolones than to tetracycline (ciprofloxacin: 39/47 and norfloxacin: 34/47 vs. tetracycline 19/47, <0.01), ampicillin, erythromycin and co-trimoxazole (21/44, 14/22 and 24/47 respectively vs. tetracycline, p = ns). CONCLUSIONS: SIBO is common in patients with MAS due to various causes and quinolones may be the preferred treatment. This needs to be proved further by a randomized controlled trial

    X-Linked thrombocytopenia causing mutations in WASP (L46P and A47D) impair T cell chemotaxis

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    BACKGROUND: Mutation in the Wiskott-Aldrich syndrome Protein (WASP) causes Wiskott-Aldrich syndrome (WAS), X-linked thrombocytopenia (XLT) and X-linked congenital neutropenia (XLN). The majority of missense mutations causing WAS and XLT are found in the WH1 (WASP Homology) domain of WASP, known to mediate interaction with WIP (WASP Interacting Protein) and CIB1 (Calcium and Integrin Binding). RESULTS: We analyzed two WASP missense mutants (L46P and A47D) causing XLT for their effects on T cell chemotaxis. Both mutants, WASP(R)(L46P) and WASP(R)(A47D) (S1-WASP shRNA resistant) expressed well in Jurkat(WASP-KD) T cells (WASP knockdown), however expression of these two mutants did not rescue the chemotaxis defect of Jurkat(WASP-KD) T cells towards SDF-1α. In addition Jurkat(WASP-KD) T cells expressing these two WASP mutants were found to be defective in T cell polarization when stimulated with SDF-1α. WASP exists in a closed conformation in the presence of WIP, however both the mutants (WASP(R)(L46P) and WASP(R)(A47D)) were found to be in an open conformation as determined in the bi-molecular complementation assay. WASP protein undergoes proteolysis upon phosphorylation and this turnover of WASP is critical for T cell migration. Both the WASP mutants were found to be stable and have reduced tyrosine phosphorylation after stimulation with SDF-1α. CONCLUSION: Thus our data suggest that missense mutations WASP(R)(L46P) or WASP(R)(A47D) affect the activity of WASP in T cell chemotaxis probably by affecting the turnover of the protein. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1186/s12929-014-0091-1) contains supplementary material, which is available to authorized users

    Diffuse idiopathic skeletal hyperostosis in ancient clergymen

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    Diffuse idiopathic skeletal hyperostosis (DISH) is a common but often unrecognized systemic disorder observed mainly in the elderly. DISH is diagnosed when the anterior longitudinal ligament of the spine is ossified on at least four contiguous spinal levels or when multiple peripheral enthesopathies are present. The etiology of DISH is unknown but previous studies have shown a strong association with obesity and insulin-independent diabetes mellitus. DISH can lead to back pain, dysphagia, myelopathy, musculoskeletal impairment and grossly unstable spine fractures after minor trauma. In archeological studies a high prevalence of DISH has been demonstrated in ancient clergymen. The present study describes the pathological changes of human remains excavated from the abbey court (Pandhof) in the city of Maastricht, The Netherlands. Human remains of 51 individuals buried between 275 and 1795 ce were excavated and examined. The remains were investigated according to a standardized physical anthropological report and individuals demonstrating ossification of spinal ligaments and/or multiple peripheral enthesopathies were included in the study group. The authors reviewed all available material and after reaching consensus, each abnormality found was given a diagnosis and subsequently recorded. After examination, 28 individuals were considered to be adult males; 11 adult females; three adults of indeterminate sex and nine individuals were of sub adult age. The mean age at death for adults was 36.8 years. Seventeen adult individuals (40.4% of all adults), displayed ossifications of at least four contiguous spinal levels and/or multiple enthesopathies of the appendicular skeleton and were therefore, assigned the diagnosis DISH. The mean age of these individuals was 49.5 ± 13.0 years. In at least three of these individuals, DISH had led to extensive ossification and subsequent ankylosis of axial and peripheral skeletal structures. In this population of (presumably) clergymen and high-ranking citizens, DISH was observed in unusual high numbers at a relatively young age. Some of the examined cases suggest that DISH may be a seriously incapacitating disorder when the more advanced stages of the disease have been reached. It is hypothesized that “a monastic way of life” can predispose to DISH. Present demographic trends in obesity and diabetes mellitus as potential co-factors for the development of DISH warrant further study to investigate its future prevalence

    Revascularization for Unprotected Left Main Coronary Artery Disease: An Evolution in Clinical Decision Making

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    Coronary artery bypass grafting (CABG) has been considered the standard therapy for unprotected (nonrevascularized) left main coronary disease (ULM). However, increasing experience with ULM percutaneous coronary intervention (PCI) has resulted in high procedural success and favorable early and late clinical outcomes. In particular, reduction in clinical restenosis with drug-eluting stents, evolution of procedural technique, and demonstration of favorable outcomes from comparative trials with CABG have promoted consideration of PCI as an alternative revascularization strategy in selected patients with ULM disease. This review summarizes the results from comparative studies examining PCI versus CABG for ULM disease, discusses changing indications for ULM PCI and identifies outstanding issues that must be considered before further advancing treatment recommendations

    Early biomarkers and potential mediators of ventilation-induced lung injury in very preterm lambs

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    BACKGROUND: Bronchopulmonary dysplasia (BPD) is closely associated with ventilator-induced lung injury (VILI) in very preterm infants. The greatest risk of VILI may be in the immediate period after birth, when the lungs are surfactant deficient, still partially filled with liquid and not uniformly aerated. However, there have been very few studies that have examined this immediate post-birth period and identified the initial injury-related pathways that are activated. We aimed to determine if the early response genes; connective tissue growth factor (CTGF), cysteine rich-61 (CYR61) and early growth response 1 (EGR1), were rapidly induced by VILI in preterm lambs and whether ventilation with different tidal volumes caused different inflammatory cytokine and early response gene expression. METHODS: To identify early markers of VILI, preterm lambs (132 d gestational age; GA, term approximately 147 d) were resuscitated with an injurious ventilation strategy (V(T) 20 mL/kg for 15 min) then gently ventilated (5 mL/kg) for 15, 30, 60 or 120 min (n = 4 in each). To determine if early response genes and inflammatory cytokines were differentially regulated by different ventilation strategies, separate groups of preterm lambs (125 d GA; n = 5 in each) were ventilated from birth with a V(T) of 5 (VG5) or 10 mL/kg (VG10) for 135 minutes. Lung gene expression levels were compared to levels prior to ventilation in age-matched control fetuses. RESULTS: CTGF, CYR61 and EGR1 lung mRNA levels were increased approximately 25, 50 and 120-fold respectively (p < 0.05), within 30 minutes of injurious ventilation. VG5 and VG10 caused significant increases in CTGF, CYR61, EGR1, IL1- , IL-6 and IL-8 mRNA levels compared to control levels. CTGF, CYR61, IL-6 and IL-8 expression levels were higher in VG10 than VG5 lambs; although only the IL-6 and CYR61 mRNA levels reached significance. CONCLUSION: CTGF, CYR61 and EGR1 may be novel early markers of lung injury and mechanical ventilation from birth using relatively low tidal volumes may be less injurious than using higher tidal volumes

    Maximization of propylene in an industrial FCC unit

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    YesThe FCC riser cracks gas oil into useful fuels such as gasoline, diesel and some lighter products such as ethylene and propylene, which are major building blocks for the polyethylene and polypropylene production. The production objective of the riser is usually the maximization of gasoline and diesel, but it can also be to maximize propylene. The optimization and parameter estimation of a six-lumped catalytic cracking reaction of gas oil in FCC is carried out to maximize the yield of propylene using an optimisation framework developed in gPROMS software 5.0 by optimizing mass flow rates and temperatures of catalyst and gas oil. The optimal values of 290.8 kg/s mass flow rate of catalyst and 53.4 kg/s mass flow rate of gas oil were obtained as propylene yield is maximized to give 8.95 wt%. When compared with the base case simulation value of 4.59 wt% propylene yield, the maximized propylene yield is increased by 95%
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