349 research outputs found

    Family Planning at Primary Health Clinics in Addis Ababa, Ethiopia

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    Honors (Bachelor's)International StudiesUniversity of Michiganhttp://deepblue.lib.umich.edu/bitstream/2027.42/120617/1/sackd.pd

    Photoredox Catalytic Activation of Trichlorofluoromethane and Addition to Styrenes

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    A new method activates CCl3F by means of photoredox catalysis and functionalizes alkenes by the CCl2F group. N-phenylphenothiazine is used as strongly reducing organophotocatalyst. The photoredox catalytic approach combines the productive disposal of this ozone depleting material and greenhouse gas with the synthesis of potentially useful organic compounds, complements the concept of atom transfer radical addition, and allows for the first time direct synthetic access to the CCl2F group as structural motif. The substrate scope is broad and the multifunctionalized class of products allows for a variety of following-up transformations

    Coastal Wave Powered Reverse Osmosis System

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    Part of the Marine Energy Collegiate Competition (MECC) is the optional Build and Test Challenge where teams are encouraged to build a portion of their proposed solution. After the conducted testing the laboratory results are compared to the simulated and calculated models. For the MECC the University of New Hampshire (UNH) team decided to use a wave energy converter to produce pressurized water. The pressurized water would be filtered through a reverse osmosis membrane to make it potable. Our system uses the power of the ocean waves to move a float up and down in heave motion. This motion drives a piston in a piston chamber. The piston and piston chamber are two separate buoys that work together to create the pressurized water. The relative motion between the piston float and the piston chamber float creates pressurized water for the reverse osmosis membrane. Our team decided to reproduce our system at a 1/8 scale and test it in the UNH wave tank in the Jere A. Chase Ocean Engineering Lab. The UNH wave tank can produce waves at specific periods and wave heights which allows testing of the device at scaled down wave heights and periods using Froude scaling

    Effect of hydrocarbon adsorption on the wettability of rare earth oxide ceramics

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    Vapor condensation is routinely used as an effective means of transferring heat, with dropwise condensation exhibiting a 5 − 7x heat transfer improvement compared to filmwise condensation. However, state-of-the-art techniques to promote dropwise condensation rely on functional hydrophobic coatings, which are often not robust and therefore undesirable for industrial implementation. Natural surface contamination due to hydrocarbon adsorption, particularly on noble metals, has been explored as an alternative approach to realize stable dropwise condensing surfaces. While noble metals are prohibitively expensive, the recent discovery of robust rare earth oxide (REO) hydrophobicity has generated interest for dropwise condensation applications due to material costs approaching 1% of gold; however, the underlying mechanism of REO hydrophobicity remains under debate. In this work, we show through careful experiments and modeling that REO hydrophobicity occurs due to the same hydrocarbon adsorption mechanism seen previously on noble metals. To investigate adsorption dynamics, we studied holmia and ceria REOs, along with control samples of gold and silica, via X-Ray photoelectron spectroscopy (XPS) and dynamic time-resolved contact angle measurements. The contact angle and surface carbon percent started at ≈0 on in-situ argon-plasma-cleaned samples and increased asymptotically over time after exposure to laboratory air, with the rare earth oxides displaying hydrophobic (>90°) advancing contact angle behavior at long times (>4 days). The results indicate that REOs are in fact hydrophilic when clean and become hydrophobic due to hydrocarbon adsorption. Furthermore, this study provides insight into how REOs can be used to promote stable dropwise condensation, which is important for the development of enhanced phase change surfaces.United States. Office of Naval ResearchUnited States. Dept. of Energy (MIT S3TEC Energy Research Frontier Center, Award No. DE- FG02-09ER46577)National Science Foundation (U.S.) (Graduate research fellowship)National Science Foundation (U.S.) (Graduate Research Fellowship Program, Grant No. 1122374)Irish Research Council for Science, Engineering, and Technology (Marie Curie Actions under FP7

    Effect of Contact Force on Pulsed Field Ablation Lesions in Porcine Cardiac Tissue.

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    BACKGROUND Contact force has been used to titrate lesion formation for radiofrequency ablation. Pulsed Field Ablation (PFA) is a field-based ablation technology for which limited evidence on the impact of contact force on lesion size is available. METHODS Porcine hearts (n=6) were perfused using a modified Langendorff set-up. A prototype focal PFA catheter attached to a force gauge was held perpendicular to the epicardium and lowered until contact was made. Contact force was recorded during each PFA delivery. Matured lesions were cross-sectioned, stained, and the lesion dimensions measured. RESULTS A total of 82 lesions were evaluated with contact forces between 1.3 g and 48.6 g. Mean lesion depth was 4.8 ± 0.9 mm (standard deviation), mean lesion width was 9.1 ± 1.3 mm and mean lesion volume was 217.0. ± 96.6 mm3 . Linear regression curves showed an increase of only 0.01 mm in depth (Depth = 0.01*Contact Force + 4.41, R2 = 0.05), 0.03 mm in width (Width = 0.03*Contact Force + 8.26, R2 = 0.13) for each additional gram of contact force, and 2.20 mm3 in volume (Volume = 2.20*Contact Force + 162, R2 = 0.10). CONCLUSIONS Increasing contact force using a bipolar, biphasic focal PFA system has minimal effects on acute lesion dimensions in an isolated porcine heart model and achieving tissue contact is more important than the force with which that contact is made. This article is protected by copyright. All rights reserved

    Health impacts of bedbug infestation: A case of five towns in Amhara Region, Ethiopia

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    Background: Bedbug is a wingless human blood-sucking bug that generally infests houses and beds. Bedbug infestation is prevalent across the country. Despite its prevalence, however, there is scarce information on the epidemiological, psychological, social and public health impacts of the infestation. This lack may arise from the absence of sufficient research in the area. The impetus for this study arose from this recognition. This study therefore assessed the extent of bedbug infestation in five towns in Amhara Regional State, Ethiopia, and its impact on public health in the areas considered in this study.Methods: A community-based cross sectional study was conducted in five towns of Amhara Regional State from 1 March 2015 to 30 June 2016. Bedbug inspection was done following the Michigan manual for prevention and control of bedbug recommendation. The presence of a living or dead bedbugs, their eggs, their skin discarded in shedding, and their fecal stains or droppings were taken as an infestation. In addition, data from households were collected using pretested, structured and interviewer-administered questionnaire. The data were analyzed using SPSS version 20. Both bivariate and multivariate logistic regressions were computed to identify associated factors.Results: From the 203 residential institutions surveyed, evidence of prevalence of bedbugs was located in 75.9% (154) houses. From among the infested residents, 87%, 83.1%, and 71.4% had faced one or more psychological, social and health impacts, respectively. Residential institutions in Bahir Dar town administration were 3.4 times more likely to be infested by bedbug than those in Amanuel town (AOR: 3.4; 95% CI: 1-11). The chances that residents of Kobo town administration had to be infested by bedbug were 41 times more than that of the residents in Amanuel town (AOR: 41; 95%CI: 8-206). However, no statistically significant difference was observed between the rates of bedbug infestation and the type of residential institutions.Conclusions: Bedbug infestation was found to be a major public health problem in Bahir Dar, Woreta and Kobo towns. A significant psychological, social and health impact was observed in the communities. Thus, aggressive public health promotion campaigns against bedbug are recommended to empower the communities and equip them with preventive strategies. Moreover, an effective pest management strategy also needs to be made a priority health agenda, in the particular areas of study. A larger study is recommended to assess more in-depth impacts of bedbug infestation on public health [Ethiop. J. Health Dev. 2017;31(4):251-258]Keywords: Bedbug infestation, Ethiopi

    Household Transmission of Rotavirus in a Community with Rotavirus Vaccination in Quininde, Ecuador

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    Background: We studied the transmission of rotavirus infection in households in peri-urban Ecuador in the vaccination era. Methods: Stool samples were collected from household contacts of child rotavirus cases, diarrhea controls and healthy controls following presentation of the index child to health facilities. Rotavirus infection status of contacts was determined by RT-qPCR. We examined factors associated with transmissibility (index-case characteristics) and susceptibility (householdcontact characteristics). Results: Amongst cases, diarrhea controls and healthy control household contacts, infection attack rates (iAR) were 55%, 8% and 2%, (n = 137, 130, 137) respectively. iARs were higher from index cases with vomiting, and amongst siblings. Disease ARs were higher when the index child was ,18 months and had vomiting, with household contact ,10 years and those sharing a room with the index case being more susceptible. We found no evidence of asymptomatic infections leading to disease transmission. Conclusion: Transmission rates of rotavirus are high in households with an infected child, while background infections are rare. We have identified factors associated with transmission (vomiting/young age of index case) and susceptibility (young age/sharing a room/being a sibling of the index case). Vaccination may lead to indirect benefits by averting episodes or reducing symptoms in vaccinees
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