Numerical study of web crippling strength in cold-formed austenitic stainless steel lipped channels with web openings subjected to interior-two-flange loading

In cold-formed stainless steel lipped channel-sections, use of web openings for service purposes are becoming increasingly popular. Web openings, however, result in the sections becoming more susceptible to web crippling. This paper presents a finite element investigation into the web crippling strength of cold-formed austenitic stainless steel lipped channel-sections with circular web openings under the interior-two-flange (ITF) loading condition. The cases of web openings located centred and offset to the bearing plates are considered in this study. In order to take into account the influence of the circular web openings, a parametric study involving 740 non-linear elasto-plastic finite element analyses was performed, covering austenitic EN1.4404 stainless steel grade. From the results of the parametric study, the effect of the size of the web opening, length of bearing plate and location of the web opening is investigated. Strength reduction factor equations are then proposed, that can be used to take into account such web openings in design

Web crippling design of cold-formed duplex stainless steel lipped channel-sections with web openings under end-one-flange loading condition

Cold-formed stainless steel sections are becoming more widely used in the residential and commercial sectors due to their high corrosion resistance and high strength-to-weight ratio. However, their susceptibility to web crippling at points of concentrated loading is well-known to be an important design issue. In addition, web openings are also become popular, as they improve ease of installation of services. This paper presents the results of an investigation into the effect of web crippling on cold-formed duplex stainless steel lipped channel-sections, having such openings, under the end-one-flange (EOF) loading condition. 728 non-linear elasto-plastic finite element analyses are undertaken, with web openings located either centred above the bearing plate or offset to bearing plate. The effect of the size of the web opening, length of bearing plate and location of the web opening is considered. Strength reduction factor equations are proposed, that can be used to take into account such openings in design

Risks, Vulnerability and Adaptation in Bangladesh

human development, climate change

Experimental and Numerical Investigation of Cold-formed Steel Sections with Web Openings under One-flange Loading Condition subjected to Web Crippling

Organised by Department of Civil Engineering, The University of Hong KongParallel Session F1D: Web Cripplingpublished_or_final_versio

Medicinal Plants as Therapeutic Alternatives to Combat Mycobacterium tuberculosis : A Comprehensive Review

Tuberculosis (TB) is a serious infectious disease caused by Mycobacterium tuberculosis (MTB) and a significant health concern worldwide. The main threat to the elimination of TB is the development of resistance by MTB to the currently used antibiotics and more extended treatment methods, which is a massive burden on the health care system. As a result, there is an urgent need to identify new, effective therapeutic strategies with fewer adverse effects. The traditional medicines found in South Asia and Africa have a reservoir of medicinal plants and plant-based compounds that are considered another reliable option for human beings to treat various diseases. Abundant research is available for the biotherapeutic potential of naturally occurring compounds in various diseases but has been lagging in the area of TB. Plant-based compounds, or phytoproducts, are being investigated as potential anti-mycobacterial agents by reducing bacterial burden or modulating the immune system, thereby minimizing adverse effects. The efficacy of these phytochemicals has been evaluated through drug delivery using nanoformulations. This review aims to emphasize the value of anti-TB compounds derived from plants and provide a summary of current research on phytochemicals with potential anti-mycobacterial activity against MTB. This article aims to inform readers about the numerous potential herbal treatment options available for combatting TB.publishedVersionPeer reviewe

Spike protein mutations and structural insights of pangolin lineage B.1.1.25 with implications for viral pathogenicity and ACE2 binding affinity

Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), the causative agent of COVID -19, is constantly evolving, requiring continuous genomic surveillance. In this study, we used whole-genome sequencing to investigate the genetic epidemiology of SARS-CoV-2 in Bangladesh, with particular emphasis on identifying dominant variants and associated mutations. We used high-throughput next-generation sequencing (NGS) to obtain DNA sequences from COVID-19 patient samples and compared these sequences to the Wuhan SARS-CoV-2 reference genome using the Global Initiative for Sharing All Influenza Data (GISAID). Our phylogenetic and mutational analyzes revealed that the majority (88%) of the samples belonged to the pangolin lineage B.1.1.25, whereas the remaining 11% were assigned to the parental lineage B.1.1. Two main mutations, D614G and P681R, were identified in the spike protein sequences of the samples. The D614G mutation, which is the most common, decreases S1 domain flexibility, whereas the P681R mutation may increase the severity of viral infections by increasing the binding affinity between the spike protein and the ACE2 receptor. We employed molecular modeling techniques, including protein modeling, molecular docking, and quantum mechanics/molecular mechanics (QM/MM) geometry optimization, to build and validate three-dimensional models of the S_D614G-ACE2 and S_P681R-ACE2 complexes from the predominant strains. The description of the binding mode and intermolecular contacts of the referenced systems suggests that the P681R mutation may be associated with increased viral pathogenicity in Bangladeshi patients due to enhanced electrostatic interactions between the mutant spike protein and the human ACE2 receptor, underscoring the importance of continuous genomic surveillance in the fight against COVID -19. Finally, the binding profile of the S_D614G-ACE2 and S_P681R-ACE2 complexes offer valuable insights to deeply understand the binding site characteristics that could help to develop antiviral therapeutics that inhibit protein–protein interactions between SARS-CoV-2 spike protein and human ACE2 receptor

Remodelling of gap junctions and connexin expression in diseased myocardium

Gap junctions form the cell-to-cell pathways for propagation of the precisely orchestrated patterns of current flow that govern the regular rhythm of the healthy heart. As in most tissues and organs, multiple connexin types are expressed in the heart: connexin43 (Cx43), Cx40 and Cx45 are found in distinctive combinations and relative quantities in different, functionally-specialized subsets of cardiac myocyte. Mutations in genes that encode connexins have only rarely been identified as being a cause of human cardiac disease, but remodelling of connexin expression and gap junction organization are well documented in acquired adult heart disease, notably ischaemic heart disease and heart failure. Remodelling may take the form of alterations in (i) the distribution of gap junctions and (ii) the amount and type of connexins expressed. Heterogeneous reduction in Cx43 expression and disordering in gap junction distribution feature in human ventricular disease and correlate with electrophysiologically identified arrhythmic changes and contractile dysfunction in animal models. Disease-related alterations in Cx45 and Cx40 expression have also been reported, and some of the functional implications of these are beginning to emerge. Apart from ventricular disease, various features of gap junction organization and connexin expression have been implicated in the initiation and persistence of the most common form of atrial arrhythmia, atrial fibrillation, though the disparate findings in this area remain to be clarified. Other major tasks ahead focus on the Purkinje/working ventricular myocyte interface and its role in normal and abnormal impulse propagation, connexin-interacting proteins and their regulatory functions, and on defining the precise functional properties conferred by the distinctive connexin co-expression patterns of different myocyte types in health and disease

The Political Economy of Tax Reform in Bangladesh: Political Settlements, Informal Institutions and the Negotiation of Reform

political economy, tax reform, political settlementsThis paper explores the political economy of tax reform in Bangladesh over several decades, shedding light on the complex factors that account for unusually effective and sustained resistance to significant reform. We contend that it is necessary to understand both deep-seated formal and informal institutions and the micro-level incentives that shape the negotiation of short-term reform in order to comprehend tax outcomes. We describe a tax system that is highly informal, largely manual and characterised by high levels of discretion and corruption. However, despite appearing highly dysfunctional on the surface, this system serves the core interests of powerful political, economic and administrative actors. Underpinned by robust informal institutions, the current system delivers low and predictable tax rates to businesses, provides extensive discretion and opportunities for corruption to the tax administration, and acts as an important vehicle for political elites to raise funds and distribute patronage and economic rents. While the tax system has not been without reform, individual reform efforts have been constrained by the parameters of this broader settlement, leaving competing interest groups to pursue strategic gains at the margins while seeking to satisfy external reform demands. This tax bargain reflects Bangladesh’s broader political economy, which is characterised by entrenched informal institutions underpinning the combination of generally weak governance and high levels of economic growth – the so-called ‘paradox of Bangladesh’.DfID, NORA

Ergocalciferol and Microcirculatory Function in Chronic Kidney Disease and Concomitant Vitamin D Deficiency: An Exploratory, Double Blind, Randomised Controlled Trial

Vitamin D deficiency and endothelial dysfunction are non-traditional risk factors for cardiovascular events in chronic kidney disease. Previous studies in chronic kidney disease have failed to demonstrate a beneficial effect of vitamin D on arterial stiffness, left ventricular mass and inflammation but none have assessed the effect of vitamin D on microcirculatory endothelial function.We conducted a randomised controlled trial of 38 patients with non diabetic chronic kidney disease stage 3-4 and concomitant vitamin D deficiency (<16 ng/dl) who received oral ergocalciferol (50,000 IU weekly for one month followed by 50,000 IU monthly) or placebo over 6 months. The primary outcome was change in microcirculatory function measured by laser Doppler flowmetry after iontophoresis of acetylcholine. Secondary endpoints were tissue advanced glycation end products, sublingual functional capillary density and flow index as well as macrovascular parameters. Parallel in vitro experiments were conducted to determine the effect of ergocalciferol on cultured human endothelial cells.Twenty patients received ergocalciferol and 18 patients received placebo. After 6 months, there was a significant improvement in the ergocalciferol group in both endothelium dependent microcirculatory vasodilatation after iontophoresis of acetylcholine (p = 0.03) and a reduction in tissue advanced glycation end products (p = 0.03). There were no changes in sublingual microcirculatory parameters. Pulse pressure (p = 0.01) but not aortic pulse wave velocity was reduced. There were no significant changes in bone mineral parameters, blood pressure or left ventricular mass index suggesting that ergocalciferol improved endothelial function independently of these parameters. In parallel experiments, expression of endothelial nitric oxide synthase and activity were increased in human endothelial cells in a dose dependent manner.Ergocalciferol improved microcirculatory endothelial function in patients with chronic kidney disease and concomitant vitamin D deficiency. This process may be mediated through enhanced expression and activity of endothelial nitric oxide synthase.Clinical trials.gov NCT00882401