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    Fertility and the Availability of Contraception in Bududa, Uganda

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    In research on fertility in developing countries, it is often assumed that lack of access to a method of affordable contraception is a significant determinant of high levels of fertility. As a result of this lack of access, actual family size exceeds desired family size. This study examines the relationship between fertility and contraception access in Bududa, an impoverished district in Uganda, which is experiencing rapid population growth. Quantitative data is combined with a series of intervals of women of childbearing age. The unexpected result is that while contraceptive use is widespread among the women in Bududa, they commonly use contraception not to reduce family size but rather to achieve optimal spacing of children in their large families. In other words, actual family size roughly equals desired family size, access to contraception primarily influences birth spacing. Instead of access to contraception, cultural and economic characteristics such as female education and compensation appear to more important determinants of fertility in Bududa, Uganda

    Integrating a Medical Screening Device into the Healthcare System of Sierra Leone

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    Information on Lehigh Ukweli Test Strips team: We produce low-cost test strips that screen for Preeclampsia and Urinary Tract Infections (UTIs) by identifying biomarkers in urine. We distribute our product to communities in developing nations by partnering with networks of Community Health Workers (CHWs) and established on-the-ground NGOs, thereby helping to bridge the gap between patients and healthcare

    LUVME: February Songs, I. Letters

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    Association of cholera toxin with Vibrio cholerae outer membrane vesicles

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    Toxigenic Vibrio cholerae is the causative organism responsible for cholera, an infectious disease characterized by acute watery diarrhea. Cholera toxin (CT), the primary virulence factor of V. cholerae, is a prototypical AB5 toxin secreted through the type II secretion pathway. Upon secretion, the toxin initiates endocytosis through the interaction of the CTB subunit with the GM1 ganglioside receptor on the small intestinal cells. In addition to the secretion of the toxin in the free, water-soluble form, V. cholerae secrete biologically active CT in association with outer membrane vesicles (OMVs). OMVs are naturally released spherical buds of the outer membranes of Gram-negative bacteria with an enveloped periplasmic content. Pathogen-derived OMVs are known to mediate the delivery of active toxins and other virulence factors to distant host cells. In this work, we sought to characterize the association of CT with V. cholerae OMVs and the role of CT-GM1 interaction in cellular uptake of vesicles. demonstrated that strain 569B releases OMVs that encapsulate CT, and which interact with host cells in a GM1-independent mechanism. Here, we have demonstrated that OMV-encapsulated CT, while biologically active, does not exist in an AB5 form; rather, the OMVs encapsulate two CTA polypeptides. We further investigated the assembly and secretion of the periplasmic CT and found that a major fraction of periplasmic CTA does not participate in the CT assembly process and instead is continuously encapsulated within the OMVs. Additionally, we found that the encapsulation of CTA fragments in OMVs is conserved among several Inaba O1 strains. We further found that under conditions in which the amount of extracellularly secreted CT increases, the concentration of OMV-encapsulated likewise CTA increases. These results point to a secondary mechanism for the secretion of biologically active CT that does not depend on the CTB-GM1 interaction for endocytosis

    The Design of Tribological Composites for Multifunctional Applications: Model Development and Topology Optimization

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    As a result of the significant economic and environmental burdens caused by wear, extensive research has been conducted to understand, predict, and control wear to achieve desired performance and lifetimes for tribological systems. Sliding interfaces in many tribological systems must also be multifunctional, prompting the need to optimize for a range of properties and processes. Composites serve as great multifunctional candidates for targeted properties and performance: including mechanical, thermal, electrical, and chemical. However, current material selection and design processes for tribological composites are often trial-and-error, time-consuming and involve significant material and energy waste. This dissertation presents a new design framework that can direct and accelerate the development of tribological composites for combined wear and thermal performance. The framework integrates three main components: (i) wear models that can predict the evolution of key metrics (surface topography, material loss, contact pressure and temperatures) (ii) wear experiments that are used to evaluate and validate the wear models and (iii) topology optimization tools that control the spatial arrangement of materials in tribological composites to achieve target multifunctional performance. In particular, existing wear models are improved and enhanced for the design of rotary and linear wear systems. One of the major contributions is the development of a thermomechanical wear model that includes frictional heat generation and transfer, along with temperature-dependent wear rates. The model developments are incorporated into several topology optimization protocols, and for the first time, a framework to design tribological composites for enhanced frictional heat dissipation is presented. The material distribution within bi-material composites is optimized to minimize temperatures at sliding interfaces while maintaining target wear performance

    Experimental Study of High-Speed Boats with Suspended Flaps for Reducing the Slamming Forces

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    This thesis consists of two parts. In the first part a small-scale high-speed monohull boat was fitted with a suspended flap under the bottom. The author tested shock absorbers for this boat, and worked on data analysis from a few initial test runs. The boat tests were performed during a few hours in a single day and the data are far too scarce to draw any conclusions. The second part of the thesis concerns multi-body numerical analysis of a suspension boat that consists of an airborne centerhull and four suspended sponsons. No simulations of boat dynamics in waves were performed. First, a brief overview of slamming problem and techniques used to reduce the vertical acceleration was conducted, full description of proposed mechanism and the instruments used to evaluate the boat behavior equipped with the mechanism, then boat testing and data analysis was illustrated. Second, advanced dynamic numerical model for the suspension boat with four sposons was developed

    Uncovering Early Synaptic Defects in Amyotrophic Lateral Sclerosis

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    State Transitions of Epileptic Seizures in Cultured Rat Hippocampal Brain Slices

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    The dynamic nature of neural activity makes prediction of epileptic seizures from electrophysiological recordings a difficult task. Understanding the states of the neural networks may lead to improvements in the prediction, control, and modeling of electrographic seizures. We explored the stability and evolution of epileptic seizures from hippocampal slices cultured on multielectrode arrays (MEA). The device recorded stable seizures that repeated for several hours. Three of the hippocampal slices that displayed continuous seizure activity for 24 hours were analyzed for state changes. Small changes in spike timings between seizures (or jitter) were calculated to quantify the transition between different states. The jitter was very small (\u3c20%) when the seizure remained in the same state, but the jitter between seizures increased as the seizure changed in shape or frequency

    Using knickpoints as geomorphic markers of crustal deformation in Appalachian Piedmont seismic clusters

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    Knickpoint elevations potentially record geomorphic signals of seismicity in slowly deforming plate interiors that lack surface expressions of underlying seismic faults. The presence or lack of cumulative differential uplift in knickpoint elevations may shed light on the mechanisms driving intraplate seismicity, namely whether there is dynamic plate-tectonic activity deep in the interior or whether seismicity is driven by topography focusing stress on favored structures. The Reading-Lancaster Seismic Zone (RLSZ) is one of several clusters of seismicity in the Appalachian Piedmont. Modeled knickpoint ages derived from channel response times to impulsive base level falls indicate that Pleistocene-age knickpoints in Susquehanna tributary streams have undergone up to 10 m/Myr of differential uplift. Regional patterns of modeled deformation are coincident with the E-W trending Westminster and Tucquan anticlines and inconsistent with N-S trending faults. This study concludes that seismicity is driven by the growth of the Westminster anticline releasing strain on preexisting faults


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