146 research outputs found

    Modern Strengthening Strategies for Steel Moment Resisting Frames: State – of – the – Art –Review

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    The Northridge (1994) and Kobe (1995) earthquakes caused widespread brittle fracture in the connections of steel moment-resisting frames. As a response to this unexpected damage, a variety of new designs have been proposed. Among many connections investigated recently, two categories of connections are mostly used to enhance ductility under severe earthquake loads. One of the two categories is the reinforced connections, in which the cover plate or haunch are used to strengthen the connections. The other category is the reduced beam section (RBS) connections. In present paper recent studies of strengthening strategies or reinforced connections are discussed. In this design philosophy, the portion of the beam adjacent to the column, where the maximum moment occurs during seismic loading, is strengthened. This will force the plastic hinge to form away from the joint. The strengthening may be done using: haunches cover plates, rib plates, side plates…etc. Keywords: Strengthening schemes, reinforced connections, cover plates, rib plates, side plates, haunche

    MMC: Multiple Metric Cost Routing Metric for Wireless Mesh Networks

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    Wireless Mesh Networks (WMNs) are bringing revolutionary changes in the field of wireless communication. Routing metric is the most important factor to find the optimized route. Researchers have shown that integrating multiple performance metrics into a routing protocol is effective for attaining optimal performance because a single metric will not be able to satisfy the comprehensive requirements of WMNs. In this paper, we propose a new routing metric for WMNs, Multiple Metric Cost (MMC), integrating three metrics: 1) Available bandwidth, 2) Residual energy and 3) Expected Transmission Count (ETX).MMC results in a better throughput. We evaluated the performance of MMC for proactive, reactive and opportunistic routing protocols using the OMNET++ network simulator. Our evaluation shows that MMC performs well in all three classes of routing protocols.

    In Silico Prediction of Evolutionarily Conserved GC-Rich Elements Associated with Antigenic Proteins of Plasmodium falciparum

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    The Plasmodium falciparum genome being AT-rich, the presence of GC-rich regions suggests functional significance. Evolution imposes selection pressure to retain functionally important coding and regulatory elements. Hence searching for evolutionarily conserved GC-rich, intergenic regions in an AT-rich genome will help in discovering new coding regions and regulatory elements. We have used elevated GC content in intergenic regions coupled with sequence conservation against P. reichenowi, which is evolutionarily closely related to P. falciparum to identify potential sequences of functional importance. Interestingly, ~30% of the GC-rich, conserved sequences were associated with antigenic proteins encoded by var and rifin genes. The majority of sequences identified in the 5′ UTR of var genes are represented by short expressed sequence tags (ESTs) in cDNA libraries signifying that they are transcribed in the parasite. Additionally, 19 sequences were located in the 3′ UTR of rifins and 4 also have overlapping ESTs. Further analysis showed that several sequences associated with var genes have the capacity to encode small peptides. A previous report has shown that upstream peptides can regulate the expression of var genes hence we propose that these conserved GC-rich sequences may play roles in regulation of gene expression

    Behavior of Reduced Beam Section Moment Connection with Varying Thickness of Continuity Plate

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    Reduced beam section (RBS) connection is investigated and is widely used in US, Japan and Europe. However, very limited study is conducted with respect to Indian profiles. This study is conducted to give advantageous factors related to RBS connections with continuity plate (CP) and to learn usefulness of those connections for Indian sections. Analytical work of reduced beam section moment connections by providing continuity plates of varying thickness under monotonic drift is presented in this paper. The model is created with finite element method (FEM) and analyzed by ANSYS workbench 16.0 software. Observations were noted for the connections with varying thickness of continuity plates and without continuity plates respectively. Similarity of the results is observed between the, the connections with CP having same thickness of beam flange and with CP having half the thickness of beam flang

    A retrospective study on maternal and perinatal outcome in pregnancy requiring DJ stent and PCN during pregnancy

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    Background: Gestational hydronephrosis (GH) is result of dilatation effect of the progesterone and mechanical compression of the gravid uterus. Management during pregnancy is challenging as routine radiological investigations and surgical treatments cannot be applied due to the potential harm to the fetus. Intervention is indicated in women who fail to respond to conservative management. Acute hydronephrosis and renal colic are common etiologies for loin pain, and can lead to severe form of urinary tract infection affecting perinatal outcome. Ureteric stenting and percutaneous nephrostomy (PCN) during pregnancy are safe, requiring no intra-operative imaging, and inserted under local anaesthesia. It provides good symptom relief, low complication rate, efficient and safe modality for women with refractory symptoms.Methods: A retrospective study of pregnant women admitted under obstetric units with acute hydronephrosis requiring DJ stenting and/or PCN. Aim was to evaluate the course and pregnancy outcomes in a tertiary center of Southern India over a period of five years.Results: Descriptive statistical analysis was done in 12 women with acute hydronephrosis in pregnancy. 66.7% were nulliparous and mean gestational age at admission was 31 weeks. Diagnosis was done by USG. One-fourth had pyelonephritis and calculus being the main pathology (n=9;75%).Women requiring DJ stent and PCN were 41.6% and 58.4% respectively. 41.7% had preterm labour. 66.7% delivered vaginally, birth weight was more than 2.5kg in 50%.Conclusions: Maternal and neonatal outcome mainly depends on the early diagnosis. In this study we emphasize on the importance of multidisciplinary team approach in the management of women with acute hydronephrosis. DJ stent and PCN are efficient and safe modalities in women with refractory symptoms

    COX-2 and PPARγ expression are potential markers of recurrence risk in mammary duct carcinoma in-situ

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    <p>Abstract</p> <p>Background</p> <p>In women with duct carcinoma in-situ (DCIS) receiving breast conservation therapy (BCT), in-breast recurrences are seen in approximately 10%, but cannot be accurately predicted using clinical and histological criteria. We performed a case-control study to identify protein markers of local recurrence risk in DCIS.</p> <p>Methods</p> <p>Women treated for DCIS with BCT, who later developed in-breast recurrence (cases) were matched by age and year of treatment to women who remained free of recurrence (controls).</p> <p>Results</p> <p>A total of 69 women were included in the study, 31 cases and 38 controls. Immunohistochemical evaluation of DCIS tissue arrays was performed for estrogen receptor, progesterone receptor, HER-2/neu, cyclin D1, p53, p21, cycloxygenase-2 (COX-2) and peroxisome proliferator activated receptor γ (PPARγ). Two markers were significantly different between cases and controls on univariate analysis: strong COX-2 expression was associated with increased risk of recurrence, with 67% vs. 24% positivity in cases and controls p = 0.006; and nuclear expression of PPARγ was associated with protection from recurrence with 4% vs. 27% positivity in cases and controls, p = 0.024. In a multivariate model which included size, grade, COX-2 and PPARγ positivity, we found COX-2 positivity to be a strong independent risk factor for recurrence (OR 7.90, 95% CI 1.72–36.23)., whereas size and grade were of borderline significance. PPARγ expression continued to demonstrate a protective trend, (OR 0.14, 95% CI 0.06–1.84).</p> <p>Conclusion</p> <p>Our findings suggest that COX-2 and PPARγ should be investigated further as biologic markers to predict DCIS recurrence, particularly since they are also potential therapeutic targets.</p

    The Case | Ectopic calcifications in a child

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    The case A nine year old boy, born of third degree consanguinity, presented with a hard left scapular swelling for 6 months. There was no history of fever, trauma or weight loss. There was no pain, redness or discharge. This mass was excised but recurred over the next 6 months (Left panel of Figure 1). A similar swelling had been excised from the left knee one year before presentation, but had recurred over 6 months. Family history was negative for similar lesions. Development was normal for age and he had no other medical problems. On examination, pulse was 84 per minute, blood pressure 96/68 mmHg, weight 22 kg and height 122 cm (both between 10th and 25th percentile). A 6 × 4 cm mass was noted in the right scapular region and a 3 × 3 cm mass at the lateral aspect of the left knee. Both of these masses were firm to hard, globular, nontender, and fixed to the bone. The overlying skin was without erythema or local warmth, though scars from the previous resections were noted. Lymphadenopathy was absent. The rest of the examination was unremarkable. Radiographs of the knee showed a lobular, inhomogenously but densely calcified lesion in the anterolateral region of the left knee (Right panel of Figure 1). Serum calcium was 9.

    Hormonal and non-hormonal oral contraceptives given long-term to pubertal rats differently affect bone mass, quality and metabolism

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    IntroductionWe investigated the effects of hormonal and non-hormonal oral contraceptives (OCs) on bone mass, mineralization, composition, mechanical properties, and metabolites in pubertal female SD rats.MethodsOCs were given for 3-, and 7 months at human equivalent doses. The combined hormonal contraceptive (CHC) was ethinyl estradiol and progestin, whereas the non-hormonal contraceptive (NHC) was ormeloxifene. MicroCT was used to assess bone microarchitecture and BMD. Bone formation and mineralization were assessed by static and dynamic histomorphometry. The 3-point bending test, nanoindentation, FTIR, and cyclic reference point indentation (cRPI) measured the changes in bone strength and material composition. Bone and serum metabolomes were studied to identify potential biomarkers of drug efficacy and safety and gain insight into the underlying mechanisms of action of the OCs.ResultsNHC increased bone mass in the femur metaphysis after 3 months, but the gain was lost after 7 months. After 7 months, both OCs decreased bone mass and deteriorated trabecular microarchitecture in the femur metaphysis and lumbar spine. Also, both OCs decreased the mineral: matrix ratio and increased the unmineralized matrix after 7 months. After 3 months, the OCs increased carbonate: phosphate and carbonate: amide I ratios, indicating a disordered hydroxyapatite crystal structure susceptible to resorption, but these changes mostly reversed after 7 months, indicating that the early changes contributed to demineralization at the later time. In the femur 3-point bending test, CHC reduced energy storage, resilience, and ultimate stress, indicating increased susceptibility to micro-damage and fracture, while NHC only decreased energy storage. In the cyclic loading test, both OCs decreased creep indentation distance, but CHC increased the average unloading slope, implying decreased microdamage risk and improved deformation resistance by the OCs. Thus, reduced bone mineralization by the OCs appears to affect bone mechanical properties under static loading, but not its cyclic loading ability. When compared to an age-matched control, after 7 months, CHC affected 24 metabolic pathways in bone and 9 in serum, whereas NHC altered 17 in bone and none in serum. 6 metabolites were common between the serum and bone of CHC rats, suggesting their potential as biomarkers of bone health in women taking CHC.ConclusionBoth OCs have adverse effects on various skeletal parameters, with CHC having a greater negative impact on bone strength

    Curriculum Setting and Pre-Clinical Dental Students' Stress Level

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    Objectives: The first two years of Dental School are commonly known to be the most stressful in a student’s academic career. Very few studies, however, consider both the pressures of dental school and their causes. In order to understand the relationship between the curriculum and its stressful effects it has on the first (D1) and second-year (D2) dental students, a cross-sectional study was performed at the University of New England College of Dental Medicine (UNE-CDM) during the fall and spring semesters of the 2015-2016 academic year. Methods: 64 D1 and 63 D2 dental students were asked to voluntarily complete an anonymous 27-question survey regarding demographic characteristics and the curriculum-related stressors. Researchers utilized the modified Dental Environment Scale (DES) to rate the stress levels. Results: This study revealed that the D2 students felt more stress than the D1 students overall. D2 students experienced more anxiety in their Spring semester of their second year. In general, students who lived with their immediate family felt less stress. Students twenty-five and over experienced less stress than their younger classmates. Conclusions: The study provided valuable information about the current structure of the curriculum at a newly established dental school. This study could provide insight into curriculum-related stress among pre-clinical dental students, which could guide dental schools in making curricular changes that help alleviate stressors during particularly stressful semesters. Furthermore, the outcomes of this project could provide dental schools the information necessary to develop student support programs to help balance students’ lives and intense course loads

    The expression of TRMT2A, a novel cell cycle regulated protein, identifies a subset of breast cancer patients with HER2 over-expression that are at an increased risk of recurrence

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    <p>Abstract</p> <p>Background</p> <p>Over-expression of <it>HER2 </it>in a subset of breast cancers (<it>HER2</it>+) is associated with high histological grade and aggressive clinical course. Despite these distinctive features, the differences in response of <it>HER2</it>+ patients to both adjuvant cytotoxic chemotherapy and targeted therapy (e.g. trastuzumab) suggests that unrecognized biologic and clinical diversity is confounding treatment strategies. Furthermore, the small but established risk of cardiac morbidity with trastuzumab therapy compels efforts towards the identification of biomarkers that might help stratify patients.</p> <p>Methods</p> <p>A single institution tissue array cohort assembled at the Clearview Cancer Institute of Huntsville (CCIH) was screened by immunohistochemistry staining using a large number of novel and commercially available antibodies to identify those with a univariate association with clinical outcome in <it>HER2</it>+ patients. Staining with antibody directed at TRMT2A was found to be strongly associated with outcome in <it>HER2</it>+ patients. This association with outcome was tested in two independent validation cohorts; an existing staining dataset derived from tissue assembled at the Cleveland Clinic Foundation (CCF), and in a new retrospective study performed by staining archived paraffin blocks available at the Roswell Park Cancer Institute (RPCI).</p> <p>Results</p> <p>TRMT2A staining showed a strong correlation with likelihood of recurrence at five years in 67 <it>HER2</it>+ patients from the CCIH discovery cohort (HR 7.0; 95% CI 2.4 to 20.1, p < 0.0004). This association with outcome was confirmed using 75 <it>HER2</it>+ patients from the CCF cohort (HR 3.6; 95% CI 1.3 to 10.2, p < 0.02) and 64 patients from the RPCI cohort (HR 3.4; 95% CI 1.3-8.9, p < 0.02). In bivariable analysis the association with outcome was independent of grade, tumor size, nodal status and the administration of conventional adjuvant chemotherapy in the CCIH and RPCI cohorts.</p> <p>Conclusions</p> <p>Studies from three independent single institution cohorts support TRMT2A protein expression as a biomarker of increased risk of recurrence in <it>HER2+ </it>breast cancer patients. These results suggest that TRMT2A expression should be further studied in the clinical trial setting to explore its predictive power for response to adjuvant cytotoxic chemotherapy in combination with <it>HER2 </it>targeted therapy.</p
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