Stability of Weak Confined Wake Behind a Cylinder in Fully Developed Turbulent Channel Flow

AbstractThe motivation for the study of instability of turbulent wake flow in a confined turbulent channel was multi-fold. First, the instability of confined wake flows has not been studied much. Second, confined wakes are found to retain their mean velocity profile for a considerable downstream distance. Third, wakes have two points of inflection, one each on either side of the centre line. The basic aim of the present study was to investigate the correlation between the turbulence in the wake region and the inflection points in the wake region using stability theory. The wake behind a cylinder of diameter d in a turbulent channel with half width h, is a weak confined wake when d/h ≈ 0.2. Thus, d/h=0.2 was chosen for the present work. Experimental results are obtained by introducing organized disturbances in the wake and tracking these downstream. Theoretical results were obtained by solving the Orr-Sommerfeld equation by numerical methods

Mutations in rpoB and katG genes of multidrug resistant mycobacterium tuberculosis undetectable using genotyping diagnostic methods

Introduction: Tuberculosis remains the leading causes of death worldwide with frequencies of mutations in rifampicin and isoniazid resistant Mycobacterium tuberculosis isolates varying according to geographical location. There is limited information in Zimbabwe on specific antibiotic resistance gene mutation patterns in MTB and hence, increased rate of discordant results and mortality due to inappropriate antibiotic prescriptions. The rpoB and katG genes molecular markers are used for detecting rifampicin and isoniazid resistance respectively. Some mutations within these gene sequences are associated with drug resistance as they directly alter gene function. The objectives of this research was to determine the drug resistance profiles in M. tuberculosis isolates that are phenotypically resistant but not detected by the GeneXpert and MTBDRplus kit and also to detect mutations in the rpoB and katG genes which are not detected by the Hain Genotype MTBDRplus kit and GeneXpert diagnosis.Methods: PCR was used for the amplification of the rpoB and katG genes from MTB isolates collected from human clinical samples between 2008 and 2015. The genes were sequenced and compared to the wild type MTB H37Rv rpoB (accession number L27989) and kat G genes (KP46920), respectively. Sequence analysis results were compared to genotyping results obtained from molecular assays and culture results of all isolates.Results: The most frequent mutation responsible for rifampicin resistance was (25/92) S531L that was detected by using all molecular assays. Some inconsistencies were observed between phenotypic and genotypic assay results for both katG and rpoB genes in 30 strains. For these, eight codons; G507S, T508A, L511V, del513-526, P520P, L524L, R528H, R529Q and S531F were novel mutations. In addition, the I572P/F, E562Q, P564S, and Q490Y mutations were identified as novel mutations outside the rifampicin resistance determining region. In katG gene, amino acid changes to threonine, asparagine and isoleucine exhibited high degrees of polymorphism such as V473N, D311N, and L427I. The R463L (20/92) amino acid substitution was most common but was not associated with isoniazid resistance.Conclusion: These finding indicate that molecular assay kit diagnosis that is based on the rpoB and katG genes should be improved to cater for the genetic variations associated with the geographic specificity of the target genes and be able to detect most prevalent mutations in different areas.Keywords: Mutation, rpoB, katG, GeneXpert, hains genotype MTBDRplus, mycobacterium tuberculosis, sequencing, DNA and PC

HIV among pregnant women in Moshi Tanzania: the role of sexual behavior, male partner characteristics and sexually transmitted infections

BACKGROUND: Women continue to be disproportionately affected by HIV in Tanzania, and factors contributing to this situation need to be identified. The objective of this study was to determine social, behavioral and biological risk factors of HIV infection among pregnant women in Moshi urban, Tanzania. In 2002 – 2004, consenting women (N = 2654), attending primary health clinics for routine antenatal care were interviewed, examined and biological samples collected for diagnosis of HIV and other sexually transmitted/reproductive tract infections. RESULTS: The prevalence of HIV was 6.9%. The risk for HIV was greater among women whose male partner; had other sexual partners (adjusted odds ratio [AOR], 15.11; 95% confidence interval [CI], 8.39–27.20), traveled frequently (AOR, 1.79; 95% CI, 1.22–2.65) or consumed alcohol daily (AOR, 1.68; 95% CI, 1.06–2.67). Other independent predictors of HIV were age, number of sex partners, recent migration, and presence of bacterial vaginosis, genital ulcer, active syphilis and herpes simplex virus type 2. CONCLUSION: Development of programs that actively involve men in HIV prevention is important in reducing transmission of HIV in this population. Further, interventions that focus on STI control, the mobile population, sexual risk behavior and responsible alcohol use are required

Increasing trend of exclusive breastfeeding over 12 years period (2002-2014) among women in Moshi, Tanzania.

BACKGROUND: The World Health Organization has recommended that all infants under 6 months should be exclusively breastfed. An understanding of the trend of exclusive breastfeeding (EBF) over years and over smaller geographical areas is crucial to monitor the progress made in improving the proportions of infants' EBF. METHODS: Data on infant feeding practices on 2315 mother-infant pairs from 2002 to 2014 were extracted from cohorts of women who delivered in the Moshi Municipality. Descriptive statistics were used to establish the trend of EBF up to 1, 3 and 6 months across waves (2002/2004 = wave I, 2005/2012 = wave II and 2013/2014 = wave III), to relate EBF up to 6 months to wealth quintiles and to HIV status of mothers. RESULTS: The number of mothers in waves I, II and III were 1656 (71.5%), 256 (11.1%) and 403(17.4%) respectively. The percentages of EBF up to 6 months increased from 5.5, 13.7 to 16.9% from wave I to III. Overall, across the waves, the proportion of EBF up to 6 months among the mothers in the low wealth quintile was 4, 9 and 42%, and 7, 26 and 15% for the ones in the highest wealth quintile. The proportion of EBF up to 6 months has been increasing among HIV positive mothers while fluctuating among their counterparts across the waves. CONCLUSION: The proportion of EBF up to 6 months has been increasing in the Moshi municipality but is below the national average. While establishing trends of EBF at the national level is commendable, research to establish trends over smaller geographical areas is needed to provide a true picture that may otherwise be masked

BMC Medicine editorial board members on open access publishing.

In recognition of Open Access week (21st-27th October 2013), we asked some BMC Medicine Editorial Board Members to share their views and experiences on open access publishing. In this short video, they highlight the benefits of visibility and dissemination of their research, and discuss the future directions for this model of publishing

Prevalence of sexually transmitted infections among pregnant women with known HIV status in northern Tanzania

<p>Abstract</p> <p>Objectives</p> <p>To determine the prevalence of sexually transmitted infections (STIs) and other reproductive tract infections (RTIs) among pregnant women in Moshi, Tanzania and to compare the occurrence of STIs/RTIs among human immunodeficiency virus (HIV)-infected and uninfected women.</p> <p>Methods</p> <p>Pregnant women in their 3^rdtrimester (N = 2654) were recruited from two primary health care clinics between June 2002 and March 2004. They were interviewed, examined and genital and blood samples were collected for diagnosis of STIs/RTIs and HIV.</p> <p>Results</p> <p>The prevalence of HIV, active syphilis and herpes simplex virus – type 2 (HSV-2) were 6.9%, 0.9% and 33.6%, respectively, while 0.5% were positive for <it>N gonorrhoeae</it>, 5.0% for <it>T vaginalis </it>and 20.9% for bacterial vaginosis. Genital tract infections were more prevalent in HIV-seropositive than seronegative women, statistically significant for syphilis (3.3% vs 0.7%), HSV-2 (43.2% vs 32.0%), genital ulcers (4.4% vs 1.4%) and bacterial vaginosis (37.2% vs 19.6%). In comparison with published data, a declining trend for curable STIs/RTIs (syphilis, trichomoniasis and bacterial vaginosis) was noted.</p> <p>Conclusion</p> <p>Rates of STIs and RTIs are still high among pregnant women in Moshi. Where resources allow, routine screening and treatment of STIs/RTIs in the antenatal care setting should be offered. Higher STIs/RTIs in HIV-seropositive women supports the expansion of HIV-counseling and testing services to all centers offering antenatal care. After identification, STIs/RTIs need to be aggressively addressed in HIV-seropositive women, both at antenatal and antiretroviral therapy care clinics.</p

Screening test for olfactory function: a new tool validated in Nepalese children

Background: Olfactory function disorders adversely affect the growth and development of children and it increases the risk of various injuries and hazards. Despite a significant problem, this area has been neglected and there is no single cross culturally validated tool to evaluate olfactory function of Nepalese children. This study was designed to determine the order recognizable by Nepalese children, which could be used as a screening test tool for olfactory function. Methods:  A total of 130 children age ranging from 4 to 10 years from six schools of Kathmandu valley were examined. (Sampling) All students of Nursery to grade 4 were divided into three age groups and tested separately for 22 different odors for the olfactory function. The child was then asked to point out the correct answer and was recorded. From the most recognized 12 odors, 7 odors were selected which exceeded the minimum threshold for a proposed screening tool. After two weeks, a revalidation test was carried out among 45 children (15 from each age group) in same schools by using 7 odors in four-fold repetition in order to determine the real identification of odor. Results: Among the 22 objects or odors tested, a 75% recognizability threshold was exceeded by 12 odors. From these 12 orders, 7 most recognized odors (apple, banana, lemon, fish, chocolate, soap and coconut) were selected for a proposed screening test tool. Retesting of the chosen odors showed satisfactory test-retest reliability, split half reliability and validity of the 7 odors test. Conclusion: We found 7 odorants, which were commonly familiar to Nepalese children and can be used to determine the orthonasal olfactory function of Nepalese children. This test is easy, quick, non-interventional and cost effective in resource restricted clinical practice setting like in Nepa

Implementation of uniform information on fetal movement in a Norwegian population reduced delayed reporting of decreased fetal movement and stillbirths in primiparous women - a clinical quality improvement

Background. Delayed maternal reporting of decreased fetal movement (DFM) is associated with adverse pregnancy outcomes. Inconsistent information on fetal activity to women during the antenatal period may result in delayed reporting of DFM. We aimed to evaluate an intervention of implementation of uniform information on fetal activity to women during the antenatal period. Methods. In a prospective before-and-after study, singleton women presenting DFM in the third trimester across 14 hospitals in Norway were registered. Outcome measures were maternal behavior regarding reporting of DFM, concerns and stillbirth. In addition, cross-sectional studies of all women giving birth were undertaken to assess maternal concerns about fetal activity, and population-based data were obtained from the Medical Birth Registry Norway. Results. Pre- and post-intervention cohorts included 19 407 and 46 143 births with 1 215 and 3 038 women with DFM respectively. Among primiparous women with DFM, a reduction in delayed reporting of DFM (48 hrs) OR 0.61 (95% CI 0.47-0.81) and stillbirths OR 0.36 (95% CI 0.19-0.69) was shown in the post-intervention period. No difference was shown in rates of consultations for DFM or maternal concerns. Stillbirth rates and maternal behavior among women who were of non-Western origin, smokers, overweight or >34 years old were unchanged. Conclusions. Uniform information on fetal activity provided to pregnant women was associated with a reduction in the number of primiparous women who delayed reporting of DFM and a reduction of the stillbirth rates for primiparous women reporting DFM. The information did not appear to increase maternal concerns or rate of consultation. Due to different imperfections in different clinical settings, further studies in other populations replicating these findings are required