108 research outputs found

    Wind-induced Torsional Loads on Low Buildings

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    Wind-induced instantaneous pressures on low building envelopes continuously vary in temporal and spatial dimensions and this may lead to significant torsional moments on the building's lateral load resisting system. Studies on wind-induced torsional loads on low buildings are very limited. Wind-induced torsion provisions in the American Society of Civil Engineers Standard (ASCE/SEI 7-10, 2010), the National Building Code of Canada (NBCC, 2010), and the European Code (EN 1991-1-4, 2005) were reviewed and compared for three gabled-roof (18.4°) low buildings. Significant discrepancies were found among the provisions of these wind standards in evaluating torsional wind loads on low buildings. In addition, wind-induced torsional loads on low buildings have been measured in a boundary layer wind tunnel. Three low buildings, with the same plan dimensions but different gabled-roof angles (0°, 18.4°, 45°) and two different heights (i.e. full, and half eave building height) were tested in simulated open and urban terrain exposures for different wind directions (from 0° to 180° every 15°). The experimental results were compared with current wind-induced torsional load provisions. It was found that NBCC (2010) underestimates the torsional moments on low buildings significantly

    Design Wind Loads Including Torsion for Rectangular Buildings with Horizontal Aspect Ratio of 1.6

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    Limited information is available regarding wind-induced torsional loads on buildings. This paper presents results of tests carried out in a boundary-layer wind tunnel using building models with the same plan dimensions (aspect ratio of 1.6) and located in a simulated open terrain exposure for different wind directions. Synchronized wind pressure measurements allowed estimating instantaneous base-shear forces and torsional moments on the tested rigid building models. Results were normalized and presented in terms of shear and torsional coefficients for two load cases, namely: maximum torsion and corresponding shear, and maximum shear and corresponding torsion. Comparison of the wind-tunnel test results with current torsion- and shear-related provisions in the American standard demonstrates good agreement for low-rise buildings but differences for medium-rise buildings

    Comparison of Wind Tunnel Measurements with NBCC 2010 Wind-Induced Torsion Provisions for Low- and Medium-Rise Buildings

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    The aim of this study is to assess wind-induced torsional loads on low- and medium-rise buildings determined in accordance with the National Building Code of Canada (NBCC 2010). Two building models with the same horizontal dimensions but different gabled-roof angles (0° and 45°) were tested at different full-scale equivalent eave heights (6, 12, 20, 30, 40, 50, and 60 m) in open terrain exposure for several wind directions (every 15°). Wind-induced measured pressures were numerically integrated over all building surfaces and results were obtained for along-wind force, across-wind force, and torsional moment. Torsion load case (i.e., maximum torsion and corresponding shear) and shear load case (i.e., maximum shear and corresponding torsion) were evaluated to reflect the maximum actual wind load effects in the two horizontal directions (i.e., transverse and longitudinal). The evaluated torsion and shear load cases were also compared with the current torsion- and shear-related provisions in the NBCC 2010. The results demonstrated significant discrepancies between NBCC 2010 and the wind tunnel measurements regarding the evaluation of torsional wind loads on low- and medium-rise buildings. Finally, shear and torsion load cases were suggested for evaluating wind loads in the design of low- and medium-rise rectangular buildings

    Torsional and Shear Wind Loads on Flat-Roofed Buildings

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    There is limited information available on wind-induced torsional loads on buildings. This paper presents results of wind tunnel tests carried out on a series of models of low- and medium-rise buildings. Four buildings with the same plan dimensions but different heights (6, 12, 25 and 50 m) were tested in a simulated open terrain exposure for different wind directions. Synchronized wind pressure measurements allowed estimating instantaneous base shear forces and torsional moments on the tested rigid building models. Results were normalized and presented in terms of mean and peak values of shear and torsional coefficients for two load cases, namely: maximum torsion and corresponding shear, and maximum shear and corresponding torsion. Comparison of the wind tunnel test results with current torsion- and shear-related provisions in the American Standard as well as the Canadian and European codes demonstrates significant discrepancies. The findings of this study could assist wind code and standards committees to improve provisions for wind-induced torsional loads on buildings

    EVALUATE THE EFFECT OF SOME FACTORS AFFECTING SOLUBILIZATION OF PHOSPHORUS IN RHIZOSPHERE

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    The aim of this work was to conduct pot experiment to study the ability of plant roots on solubilizing various sources of phosphorus and factors that may facilitate or inhibit their activity. A split medium – split root technique experiment was conducted to study the effect of CaCO3, pH, organic matter (humic acid) and bentonite on the pH, P solubility in the medium and P concentration in bean plants (Vicia faba var. balady). The changes in pH of the lower solution was recorded, also the root exudate was collected in 500 ml of CaCl2 solution 0.5 × 10-4 M and pH 6.85.  Results showed that the highest recorded total dry weight was found when both N forms were applied in the ratio of 1:4 NO-3: NH+4 or NO-3 alone. The mechanism of solubilizing rock phosphate by exudating protons or organic, amino and other organic compounds is possible at the root surface even in alkaline soil as long as the rock phosphate material was added near the root and organic matter was added to limit the fixing power of the inorganic components as CaCO3 and excess soluble Ca. Also, the availability of P from rock phosphate sources depends on its reactivity value

    Targeted enrichment of genomic DNA regions for next-generation sequencing

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    In this review, we discuss the latest targeted enrichment methods and aspects of their utilization along with second-generation sequencing for complex genome analysis. In doing so, we provide an overview of issues involved in detecting genetic variation, for which targeted enrichment has become a powerful tool. We explain how targeted enrichment for next-generation sequencing has made great progress in terms of methodology, ease of use and applicability, but emphasize the remaining challenges such as the lack of even coverage across targeted regions. Costs are also considered versus the alternative of whole-genome sequencing which is becoming ever more affordable. We conclude that targeted enrichment is likely to be the most economical option for many years to come in a range of settings

    Topical Application of Sadat-Habdan Mesenchymal Stimulating Peptide (SHMSP) Accelerates Wound Healing in Diabetic Rabbits

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    Objective. Diminished wound healing is a common problem in diabetic patients due to diminished angiogenesis. SHMSP was found to promote angiogenesis. The present study was carried out to examine the effect of this peptide in healing of wounds in diabetic rabbits. Materials and Methods. Twenty male New Zealand rabbits were used in this study. Diabetes mellitus was induced and the rabbits were randomly divided into two equal groups: control group and peptide group. A-full thickness punch biopsy was made to create a wound of about 10 mm on the right ears of all rabbits. Every day, the wound was cleaned with saline in control groups. In the peptide group, 15 mg of SHMSP was applied after cleaning. On day 15th, all animals were sacrificed, and the wounds were excised with a rim of 5 mm of normal surrounding tissue. Histo-pathological assessment of wound healing, inflammatory cell infiltration, blood vessel proliferation, and collagen deposition was performed. Results. There were no deaths among the groups. There was significant increase in wound healing, blood vessel proliferation and collagen deposition, and significant decrease in inflammatory cell infiltration in the peptide group compared to the control group. Conclusion. Topical application of SHMSP improves wound healing in diabetic rabbits

    Visual histological assessment of morphological features reflects the underlying molecular profile in invasive breast cancer: a morphomolecular study

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    © 2020 The Authors. Histopathology published by John Wiley & Sons Ltd Aims: Tumour genotype and phenotype are related and can predict outcome. In this study, we hypothesised that the visual assessment of breast cancer (BC) morphological features can provide valuable insight into underlying molecular profiles. Methods and results: The Cancer Genome Atlas (TCGA) BC cohort was used (n=743) and morphological features, including Nottingham grade and its components and nucleolar prominence, were assessed utilising whole-slide images (WSIs). Two independent scores were assigned, and discordant cases were utilised to represent cases with intermediate morphological features. Differentially expressed genes (DEGs) were identified for each feature, compared among concordant/discordant cases and tested for specific pathways. Concordant grading was observed in 467 of 743 (63%) of cases. Among concordant case groups, eight common DEGs (UGT8, DDC, RGR, RLBP1, SPRR1B, CXorf49B, PSAPL1 and SPRR2G) were associated with overall tumour grade and its components. These genes are related mainly to cellular proliferation, differentiation and metabolism. The number of DEGs in cases with discordant grading was larger than those identified in concordant cases. The largest number of DEGs was observed in discordant grade 1:3 cases (n=1185). DEGs were identified for each discordant component. Some DEGs were uniquely associated with well-defined specific morphological features, whereas expression/co-expression of other genes was identified across multiple features and underlined intermediate morphological features. Conclusion: Morphological features are probably related to distinct underlying molecular profiles that drive both morphology and behaviour. This study provides further evidence to support the use of image-based analysis of WSIs, including artificial intelligence algorithms, to predict tumour molecular profiles and outcome

    Heritability in the Efficiency of Nonsense-Mediated mRNA Decay in Humans

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    BACKGROUND: In eukaryotes mRNA transcripts of protein-coding genes in which an intron has been retained in the coding region normally result in premature stop codons and are therefore degraded through the nonsense-mediated mRNA decay (NMD) pathway. There is evidence in the form of selective pressure for in-frame stop codons in introns and a depletion of length three introns that this is an important and conserved quality-control mechanism. Yet recent reports have revealed that the efficiency of NMD varies across tissues and between individuals, with important clinical consequences. PRINCIPAL FINDINGS: Using previously published Affymetrix exon microarray data from cell lines genotyped as part of the International HapMap project, we investigated whether there are heritable, inter-individual differences in the abundance of intron-containing transcripts, potentially reflecting differences in the efficiency of NMD. We identified intronic probesets using EST data and report evidence of heritability in the extent of intron expression in 56 HapMap trios. We also used a genome-wide association approach to identify genetic markers associated with intron expression. Among the top candidates was a SNP in the DCP1A gene, which forms part of the decapping complex, involved in NMD. CONCLUSIONS: While we caution that some of the apparent inter-individual difference in intron expression may be attributable to different handling or treatments of cell lines, we hypothesize that there is significant polymorphism in the process of NMD, resulting in heritable differences in the abundance of intronic mRNA. Part of this phenotype is likely to be due to a polymorphism in a decapping enzyme on human chromosome 3

    Systematic Association Mapping Identifies NELL1 as a Novel IBD Disease Gene

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    Crohn disease (CD), a sub-entity of inflammatory bowel disease (IBD), is a complex polygenic disorder. Although recent studies have successfully identified CD-associated genetic variants, these susceptibility loci explain only a fraction of the heritability of the disease. Here, we report on a multi-stage genome-wide scan of 393 German CD cases and 399 controls. Among the 116,161 single-nucleotide polymorphisms tested, an association with the known CD susceptibility gene NOD2, the 5q31 haplotype, and the recently reported CD locus at 5p13.1 was confirmed. In addition, SNP rs1793004 in the gene encoding nel-like 1 precursor (NELL1, chromosome 11p15.1) showed a consistent disease-association in independent German population- and family-based samples (942 cases, 1082 controls, 375 trios). Subsequent fine mapping and replication in an independent sample of 454 French/Canadian CD trios supported the authenticity of the NELL1 association. Further confirmation in a large German ulcerative colitis (UC) sample indicated that NELL1 is a ubiquitous IBD susceptibility locus (combined p<10−6; OR = 1.66, 95% CI: 1.30–2.11). The novel 5p13.1 locus was also replicated in the French/Canadian sample and in an independent UK CD patient panel (453 cases, 521 controls, combined p<10−6 for SNP rs1992660). Several associations were replicated in at least one independent sample, point to an involvement of ITGB6 (upstream), GRM8 (downstream), OR5V1 (downstream), PPP3R2 (downstream), NM_152575 (upstream) and HNF4G (intron)
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