Symmetrical and Anti-Symmetrical Buckling of Long Corroded Cylindrical Shell Subjected to External Pressure

This paper derives an exact analytical solution for determining elastic critical buckling pressures and mode shapes for very long corroded cylindrical steel shells subjected to external pressure considering symmetrical and anti-symmetrical mode cases. The corroded long cylindrical shell has been modelled as a non-uniform “stepped-type” ring consisting of two portions- corroded and un-corroded regions. A full range parametric study has been made to investigate the effect of corrosion angular extent and corrosion thickness on the elastic buckling pressures and their modes. The study shows that buckling loads and modes depend on the corrosion angular extent â and the corroded to un-corroded thicknesses ratio. The results are verified by a set of investigations with a series of corroded cylindrical shells. They showed a close agreement with those obtained from using the finite element package ABAQUS

Experimental models for the autoimmune and inflammatory blistering disease, Bullous pemphigoid

Bullous pemphigoid (BP) is a subepidermal skin blistering disease characterized immunohistologically by dermal-epidermal junction (DEJ) separation, an inflammatory cell infiltrate in the upper dermis, and autoantibodies targeted toward the hemidesmosomal proteins BP230 and BP180. Development of an IgG passive transfer mouse model of BP that reproduces these key features of human BP has demonstrated that subepidermal blistering is initiated by anti-BP180 antibodies and mediated by complement activation, mast cell degranulation, neutrophil infiltration, and proteinase secretion. This model is not compatible with study of human pathogenic antibodies, as the human and murine antigenic epitopes are not cross-reactive. The development of two novel humanized mouse models for the first time has enabled study of disease mechanisms caused by BP autoantibodies, and presents an ideal in vivo system to test novel therapeutic strategies for disease management

Vaginal infections among pregnant women at Omdurman Maternity Hospital in Khartoum, Sudan

Microbial infections of the vagina (vaginosis and vaginitis) among pregnant women are serious problems because they can lead to serious medical co mplications such as preterm labor, amniotic fluid infection, premature rupture of the fetal membranes, and low birth weight of the neonate [1], leading to high prenatal mortality [2]. However, proper identification and treatment will reduce the risk of pre term birth and its consequences [3]ntroduction: Microbial infections of the vagina in pregnant women are health problems that lead to serious medical complicat ions and consequences. This study aimed to investigate and determine antimicrobial susceptibilities of the causative agents of vagi nal infections in pregnant women. Methodology: A cross - sectional study of pregnant women (n = 200) was conducted between August and December 2008 at Omdurman Maternity Hospital, Khartoum, Sudan. Vaginal and cervical swabs were obtained from each subject a nd processed for isolation and identification of pathogenic microorganisms using standard methods of wet mount preparation, direct Gram smear, Nugent scorin g system, direct immunofluorescence, and cultural techniques. Antimicrobial susceptibility testing o f bacterial isolates was performed using standard procedures. Statistical analysis was done using SPSS program version 12.0.1. A p value < 0.05 was considered statistically si gnificant. Results: Of the 200 pregnant women enrolled, BV was detected in 49.8%, followed by Chlamydia trachomatis (31.3%) and Candida albicans (16.6%), with low frequencies of Neisseria gonorrhoeae (1.8%) and Trichomonas vaginalis (0.5%). Higher infection rates were recorded among subjects in the third trimester (71.6%) than in the s econd trimester of gestation (28.4%). No significant association (p = 0.7) between history of abortions and C. trachomatis infections was found. Gentamicin was the most active agent against Gram - positive and Gram - negative bacteria. Clarythromycin was the m ost active against Mycoplasma species. Conclusions: Pregnant women with vaginal complaints revealed various positive microbiology results. Such cases may require sp ecific medication. Routine culture of vaginal and cervical samples should be performed on a ll pregnant women during prenatal visits

Modeling and Analysis of Proof-Based Strategies for Distributed Consensus in Blockchain-Based Peer-to-Peer Networks

Blockchain technology has a wide range of applicability in the fields of transportation infrastructure construction and maintenance, transportation big data analysis and application, expressway toll collection, and logistics. The core technology lies in the distributed, decentralized, immutable, and programmable features brought about by consensus. This paper studies the dynamic analytical modeling of Proof-Based Consensus (PBC) strategies in blockchain systems, focusing on basic strategies, including Proof of Work (PoW), Proof of Stake (PoS), Proof of Authority (PoA), and Proof of Luck (PoL), which can be extended to other PBC models. We focus on modeling these typical strategies and discuss their solution characteristics in terms of algorithmic mechanisms and principles. The relevant results can be used for quantitative analysis and evaluation of distributed consensus based on the model