The effects of thermomechanical history on the microstructure of a nickel-base superalloy during forging

The effect of thermo-mechanical history on hot compression behaviour and resulting microstructures of a nickel base superalloy is presented. Hot compression tests were carried out on HAYNES® 282® specimens to varying strains from 0.1 to 0.8. Both single pass and multi-pass tests were completed. 60 minute inter-pass times were utilized to accurately replicate industrial forging practices. The effect of dynamic, metadynamic and static recrystallization during inter-pass times on flow stress was investigated. The study showed the presence of yield peaks in the flow stress data which have been identified in previous studies and thought to be due to solute atoms pinning dislocations, but in this work are shown to be due to friction. The resulting microstructures were analysed using scanning electron, optical microscopy and EBSD to relate grain size and homogeneity with flow stress data. The study showed a negligible difference between multi-pass and single pass tests for strain increments above 0.2. Therefore, when modelling similar low strain and strain rate forging processes inHAYNES® 282®, previous forging steps can be ignored

High residual prevalence of vaccine-serotype Streptococcus pneumoniae carriage after introduction of a pneumococcal conjugate vaccine in Malawi: a prospective serial cross-sectional study

Background: There are concerns that pneumococcal conjugate vaccines (PCV) in sub-Saharan Africa sub-optimally interrupt vaccine-serotype (VT) carriage and transmission, thus limiting vaccine-induced direct and indirect protection. We assessed carriage in vaccinated children and unvaccinated populations targeted for indirect protection, between 4 and 7 years after Malawi’s November 2011 introduction of PCV13 using a 3+0 schedule. / Methods: We conducted sequential prospective nasopharyngeal carriage surveys between 2015 and 2018 among healthy PCV-vaccinated and PCV-unvaccinated children, and HIV-infected adults. VT and NVT carriage risk by age was analysed by non-linear regression. / Results: Among PCV-vaccinated children, there was a 24% relative reduction in carriage, from a mean 21.1% to 16.1%; 45% reduction among older PCV-unvaccinated children, from 27.5% to 15.2%; 41.4% reduction among adults, from 15.2% to 8.9%. Using carriage data from children 3.6 to 10 years of age, VT carriage probability declined with age, with a similar prevalence half-life among PCV-vaccinated (3.34 years) and PCV-unvaccinated (3.26 years) children. / Conclusion: Compared to high-income settings, the 3+0 schedule in Malawi has led to a sub-optimal reduction in pneumococcal carriage prevalence. This is likely due to recolonisation of vaccinated children with waning vaccine-induced immunity, resulting in insufficient indirect protection of unvaccinated populations. Rigorous evaluation of strategies to augment vaccine-induced control of carriage, including alternative schedules and catch-up campaigns is required

Design and operating experience of the cryogenic system of the U. S. SCMS as incorporated into the bypass loop of the U-25 MHD generator facility

The design features and accumulated operating experience, from a cryogenics point of view, of the United States Superconducting Magnet System (U.S. SCMS) are presented. The principal cryogenic system design parameters are enumerated. Details of the cryogenic aspects of magnetic system commissioning, standby mode, and operation with MHD generators are discussed. Included are system operation, problems encountered and corrective actions taken, and measured operating parameters which include liquid helium boiloff, cryostat pressure and level versus time, etc. The aspects of the transition between operation in the laboratory and in an MHD plant are elaborated

Cryogenic aspects of the experience in operating the U-25 superconducting MHD magnet in conjunction with the MHD generator

In order to facilitate the rapid development of MHD technology for the generation of electrical energy, the U.S. and U.S.S.R. are jointly conducting research within the framework of the Program of Scientific and Technical Cooperation. The Institute for High Temperature (IVTAN) of the U.S.S.R. has designed and fabricated a special MHD facility which uses as its base much of the equipment of the existing U-25 Facility. The new MHD fow train consisting of a combustor, magnet, channel, and diffuser is named U-25B. The U.S. has provided a superconducting magnet system for the U-25B MHD Facility. As a result of these joint efforts, a unique and broad range of experimental test conditions similar to those that will exist in operation of commercial MHD generators has been created. The United States Superconducting Magnet System (U.S. SCMS) was designed, fabricated, and delivered to the U-25B Facility by the Argonne National Laboratory (ANL) under the sponsorship of the U.S. Department of Energy. The following description focuses on the cryogenic-related aspects of the magnet system commissioning and operation in the U.S.S.R

Chorioamnionitis: Case definition & guidelines for data collection, analysis, and presentation of immunization safety data

Chorioamnionitis is a term encompassing a broad spectrum of disease during pregnancy that is characterized by inflammation and/or infection of intrauterine structures such as the placenta, the chorion and amnion. The clinical presentation of chorioamnionitis can vary based on clinical, microbiologic, and histologic factors which interact and overlap to varying degrees

Prevalence of complications of male circumcision in Anglophone Africa: a systematic review

BACKGROUND: There is growing evidence that male circumcision (MC) prevents heterosexual acquisition of HIV by males in sub-Saharan Africa, the region of the world heavily affected by the HIV pandemic. While there is growing support for wide-spread availability and accessibility of MC in Africa, there is limited discussion about the prevalence of physical complications of male circumcision on the continent. METHODS: A systematic literature search and review of articles in indexed journals and conference abstracts was conducted to collect and analyze prevalence of complications of MC in Anglophone sub-Saharan Africa. Information extracted included: indications for MC, complications reported, age of patients and category of circumcisers. RESULTS: There were 8 articles and 2 abstracts that were suitable for the analysis. The studies were not strictly comparable as some reported on a wide range of complications while others reported just a limited list of possible complications. Prevalence of reported complications of MC ranged from 0% to 50.1%. Excluding the study with 50.1%, which was on a series of haemophilia patients, the next highest prevalence of complications was 24.1%. Most of the complications were minor. There was no firm evidence to suggest that MCs performed by physician surgeons were associated with lower prevalence of complications when compared with non-physician health professionals. CONCLUSION: The available data are inadequate to obtain a reasonable assessment of the prevalence of complications of MC in sub-Saharan Africa. Some of the available studies however report potentially significant prevalence of complications, though of minor clinical significance. This should be considered as public health policy makers consider whether to scale-up MC as an HIV preventative measure. Decision for the scale-up will depend on a careful cost-benefit assessment of which physical complications are certainly an important aspect. There is need for standardized reporting of complications of male circumcision

A Randomized Trial of Prophylactic Antibiotics for Miscarriage Surgery.

BACKGROUND: Surgical intervention is needed in some cases of spontaneous abortion to remove retained products of conception. Antibiotic prophylaxis may reduce the risk of pelvic infection, which is an important complication of this surgery, particularly in low-resource countries. METHODS: We conducted a double-blind, placebo-controlled, randomized trial investigating whether antibiotic prophylaxis before surgery to complete a spontaneous abortion would reduce pelvic infection among women and adolescents in low-resource countries. We randomly assigned patients to a single preoperative dose of 400 mg of oral doxycycline and 400 mg of oral metronidazole or identical placebos. The primary outcome was pelvic infection within 14 days after surgery. Pelvic infection was defined by the presence of two or more of four clinical features (purulent vaginal discharge, pyrexia, uterine tenderness, and leukocytosis) or by the presence of one of these features and the clinically identified need to administer antibiotics. The definition of pelvic infection was changed before the unblinding of the data; the original strict definition was two or more of the clinical features, without reference to the administration of antibiotics. RESULTS: We enrolled 3412 patients in Malawi, Pakistan, Tanzania, and Uganda. A total of 1705 patients were assigned to receive antibiotics and 1707 to receive placebo. The risk of pelvic infection was 4.1% (68 of 1676 pregnancies) in the antibiotics group and 5.3% (90 of 1684 pregnancies) in the placebo group (risk ratio, 0.77; 95% confidence interval [CI], 0.56 to 1.04; P = 0.09). Pelvic infection according to original strict criteria was diagnosed in 1.5% (26 of 1700 pregnancies) and 2.6% (44 of 1704 pregnancies), respectively (risk ratio, 0.60; 95% CI, 0.37 to 0.96). There were no significant between-group differences in adverse events. CONCLUSIONS: Antibiotic prophylaxis before miscarriage surgery did not result in a significantly lower risk of pelvic infection, as defined by pragmatic broad criteria, than placebo. (Funded by the Medical Research Council and others; AIMS Current Controlled Trials number, ISRCTN97143849.)

Human resources requirements for highly active antiretroviral therapy scale-up in Malawi

<p>Abstract</p> <p>Background</p> <p>Twelve percent of the adult population in Malawi is estimated to be HIV infected. About 15% to 20% of these are in need of life saving antiretroviral therapy. The country has a public sector-led antiretroviral treatment program both in the private and public health sectors. Estimation of the clinical human resources needs is required to inform the planning and distribution of health professionals.</p> <p>Methods</p> <p>We obtained data on the total number of patients on highly active antiretroviral treatment program from the Malawi National AIDS Commission and Ministry of Health, HIV Unit, and the number of registered health professionals from the relevant regulatory bodies. We also estimated number of health professionals required to deliver highly active antiretroviral therapy (HAART) using estimates of human resources from the literature. We also obtained data from the Ministry of Health on the actual number of nurses, clinical officers and medical doctors providing services in HAART clinics. We then made comparisons between the human resources situation on the ground and the theoretical estimates based on explicit assumptions.</p> <p>Results</p> <p>There were 610 clinicians (396 clinical officers and 214 physicians), 44 pharmacists and 98 pharmacy technicians and 7264 nurses registered in Malawi. At the end of March 2007 there were 85 clinical officer and physician full-time equivalents (FTEs) and 91 nurse FTEs providing HAART to 95,674 patients. The human resources used for the delivery of HAART comprised 13.9% of all clinical officers and physicians and 1.1% of all nurses. Using the estimated numbers of health professionals from the literature required 15.7–31.4% of all physicians and clinical officers, 66.5–199.3% of all pharmacists and pharmacy technicians and 2.6 to 9.2% of all the available nurses. To provide HAART to all the 170,000 HIV infected persons estimated as clinically eligible would require 4.7% to 16.4% of the total number of nurses, 118.1% to 354.2% of all the available pharmacists and pharmacy technicians and 27.9% to 55.7% of all clinical officers and physicians. The actual number of health professionals working in the delivery of HAART in the clinics represented 44% to 88.8% (for clinical officers and medical doctors) and 13.6% and 47.6% (for nurses), of what would have been needed based on the literature estimation.</p> <p>Conclusion</p> <p>HAART provision is a labour intensive exercise. Although these data are insufficient to determine whether HAART scale-up has resulted in the weakening or strengthening of the health systems in Malawi, the human resources requirements for HAART scale-up are significant. Malawi is using far less human resources than would be estimated based on the literature from other settings. The impact of HAART scale-up on the overall delivery of health services should be assessed.</p

A rapid, reproducible, noninvasive predictor of liver graft survival

BACKGROUND: Clinical and laboratory criteria are not reliable predictors of deceased donor liver graft quality. Intraoperative assessment of experienced surgeons is the gold standard. Standardizing and quantifying this assessment is especially needed now that regional sharing is the rule. We prospectively evaluated a novel, simple, rapid, noninvasive, quantitative measure of liver function performed before graft procurement. MATERIALS AND METHODS: Using a portable, finger-probe–based device, indocyanine green plasma disappearance rates (ICG-PDR) were measured in adult brain-dead donors in the local donor service area before organ procurement. Results were compared with graft function and outcomes. Both donor and recipient teams were blinded to ICG-PDR measurements. RESULTS: Measurements were performed on 53 consecutive donors. Eleven liver grafts were declined by all centers because of quality; the other 42 grafts were transplanted. Logistic regression analysis showed ICG-PDR to be the only donor variable to be significantly associated with 7-d graft survival. Donor risk index, donor age, and transaminase levels at peak or procurement were not significantly associated with 7-d graft survival. CONCLUSIONS: We report the successful use of a portable quantitative means of measuring liver function and its association with graft survival. These data warrant further exploration in a variety of settings to evaluate acceptable values for donated liver grafts