Computational Prediction of Pressure and Thermal Environments in the Flame Trench With Launch Vehicles

One of the key objectives for the development of the 21st Century Space Launch Com- plex is to provide the exibility needed to support evolving launch vehicles and spacecrafts with enhanced range capacity. The launch complex needs to support various proprietary and commercial vehicles with widely di erent needs. The design of a multi-purpose main ame de ector supporting many di erent launch vehicles becomes a very challenging task when considering that even small geometric changes may have a strong impact on the pressure and thermal environment. The physical and geometric complexity encountered at the launch site require the use of state-of-the-art Computational Fluid Dynamics (CFD) tools to predict the pressure and thermal environments. Due to harsh conditions encountered in the launch environment, currently available CFD methods which are frequently employed for aerodynamic and ther- mal load predictions in aerospace applications, reach their limits of validity. This paper provides an in-depth discussion on the computational and physical challenges encountered when attempting to provide a detailed description of the ow eld in the launch environ- ment. Several modeling aspects, such as viscous versus inviscid calculations, single-species versus multiple-species ow models, and calorically perfect gas versus thermally perfect gas, are discussed. The Space Shuttle and the Falcon Heavy launch vehicles are used to study di erent engine and geometric con gurations. Finally, we provide a discussion on traditional analytical tools which have been used to provide estimates on the expected pressure and thermal loads

Diagnostic accuracy of body mass index and fasting glucose for the prediction of gestational diabetes mellitus after assisted reproductive technology

Background: The aim of the present study was to determine the maternal pre-pregnancy body mass index (BMI), first-trimester fasting blood sugar (FBS), and the combination of (BMI+FBS) cut-points for at-risk pregnant women conceived by assisted reproductive technology (ART) to better predict the risk of developing gestational diabetes mellitus (GDM) in infertile women. Materials and Methods: In this nested case-control study, 270 singleton pregnant women consisted of 135 (GDM) and 135 (non-GDM) who conceived using ART were assessed. The diagnosis of GDM was confirmed by a one-step glucose tolerance test (O-GTT) using 75 g oral glucose. BMI was classified base on World Health Organization (WHO) criteria. The relationship between BMI, FBS, and BMI+FBS with the risk of GDM development was determined by logistic regression and adjusted for confounding factors. Receiver operating characteristic (ROC) curve analysis was performed to assess the value of BMI, FBS, and BMI+FBS for the prediction of GDM. Results: The GDM group had significantly higher age, BMI, family history of diabetes, and history of polycystic ovary syndrome in comparison with the non-GDM group (P<0.05). Overweight and obese women had 3.27, and 5.14 folds increase in the odds of developing GDM, respectively. There was a 17 increase in the risk of developing GDM with each 1 mg/dl increase in fasting glucose level. The cut points for FBS 84.5 mg/dl (72.9 sensitivity, 74.4 specificity), BMI 25.4 kg/m 2 (68.9 sensitivity, 62.8 specificity), and BMI+FBS 111.2 (70.7 sensitivity, 80.6 specificity) was determined. Conclusion: The early screening and high-quality prenatal care should be recommended upon the co-occurrence of high FBS (�84.5 mg/dl) in the first-trimester of the pregnancy and the BMI (�25.4 kg/m2) in pre-pregnancy period in women undergone ART. The combination of BMI and FBS is considered a better prediction value. © 2019, Royan Institute (ACECR). All rights reserved

Active Methamphetamine Use is Associated with Transmitted Drug Resis-tance to Non-Nucleoside Reverse Transcriptase Inhibitors in Individuals with HIV Infection of Unknown Duration

BackgroundFrequent methamphetamine use among recently HIV infected individuals is associated with transmitted drug resistance (TDR) to non-nucleoside reverse transcriptase inhibitors (NNRTI); however, the reversion time of TDR to drug susceptible HIV may exceed 3 years. We assessed whether recreational substance use is associated with detectable TDR among individuals newly diagnosed with HIV infection of unknown duration.DesignCross-sectional analysis.MethodsSubjects were enrolled at the University California, San Diego Early Intervention Program. Demographic, clinical and substance use data were collected using structured interviews. Genotypic resistance testing was performed using GeneSeq, Monogram Biosciences. We analyzed the association between substance use and TDR using bivariate analyses and the corresponding transmission networks using phylogenetic models.ResultsBetween April 2004 and July 2006, 115 individuals with genotype data were enrolled. The prevalence of alcohol, marijuana and methamphetamine use were 98%, 71% and 64% respectively. Only active methamphetamine use in the 30 days prior to HIV diagnosis was independently associated with TDR to NNRTI (OR: 6.6; p=0.002).ConclusionDespite not knowing the duration of their HIV infection, individuals reporting active methamphetamine use in the 30 days prior to HIV diagnosis are at an increased risk of having HIV strains that are resistant to NNRTI

Cost-effectiveness of a population-based AAA screening program for men over 65 years old in Iran

Background: Screening program tend to recognized patients in their early stage and consequently improve health outcomes. Cost-effectiveness of the abdominal aortic aneurysm (AAA) screening program has been scarcely studied in developing countries. We sought to evaluate the cost-effectiveness of a screening program for the abdominal aortic aneurysm (AAA) in men aged over 65 years in Iran. Methods: A Markov cohort model with 11 mutually exclusive health statuses was used to evaluate the cost-effectiveness of a population-based AAA screening program compared with a no-screening strategy. Transitions between the health statuses were simulated by using 3-month cycles. Data for disease transition probabilities and quality of life outcomes were obtained from published literature, and costs were calculated based on the price of medical services in Iran and the examination of the patients� medical records. The outcomes were life-years gained, the quality-adjusted life-year (QALY), costs, and the incremental cost-effectiveness ratio (ICER). The analysis was conducted for a lifetime horizon from the payer�s perspective. Costs and effects were discounted at an annual rate of 3. Uncertainty surrounding the model inputs was tested with deterministic and probabilistic sensitivity analyses. Results: The mean incremental cost of the AAA screening strategy compared with the no-screening strategy was 140 and the mean incremental QALY gain was 0.025 QALY, resulting in an ICER of 5566 (14,656 PPP) per QALY gained. At a willingness-to-pay of 1 gross domestic product (GDP) per capita (5628) per QALY gained, the probability of the cost-effectiveness of AAA screening was about 50. However, at a willingness-to-pay of twice the GDP per capita per QALY gained, there was about a 95 probability for the AAA screening program to be cost-effective in Iran. Conclusions: The results of this study showed that at a willingness-to-pay of 1 GDP per capita per QALY gained, a 1-time AAA screening program for men aged over 65 years could not be cost-effective. Nevertheless, at a willingness-to-pay of twice the GDP per capita per QALY gained, the AAA screening program could be cost-effective in Iran. Further, AAA screening in high-risk groups could be cost-effective at a willingness-to-pay of 1 GDP per capita per QALY gained. © 2021, The Author(s)

Mothers and their children�s health (MATCH): a study protocol for a population�based longitudinal cohort

Background: The quality of prenatal care is critical for the prevention of adverse pregnancy outcomes. However, according to the World Health Organization (WHO), only 64 of women worldwide have access to over four sessions of prenatal care throughout their pregnancy. Thus, studies that address factors affecting maternal and child health status before and after pregnancy are of immense importance. The primary aim of the mothers and their children�s health (MATCH) cohort study is to evaluate the effect of nutrition, sleep quality, and lifestyle on maternal and neonatal outcomes. Methods: A prospective cohort of > 2500 pregnant women in the first trimester (before 12 weeks� gestation) will be recruited at Arash Women�s Hospital in Tehran, Iran between February 2020 and August 2021. All eligible pregnant women will be followed from their first trimester of pregnancy until delivery at four time points and assessed through a series of in-person visits with interviewer-administered questionnaires and telephone interviews. Detailed data will be collected on maternal demographics, lifestyle, medical history, reproductive history, obstetric history, dietary intake, sleep pattern, blood specimens, and anthropometric measurements, alongside paternal demographics, lifestyle, and family history. The outcomes will include antenatal, peripartum, and postnatal maternal complications and infant growth and neurodevelopment. Discussion: The results of the MATCH cohort study will support the development of contextual interventions that can enhance antenatal, peripartum, and postnatal status, neonatal outcomes, and longevity mother and child. © 2021, The Author(s)