4,351 research outputs found

    Tube coupling device

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    A first annular ring of a tube coupling device has a keyed opening sized to fit around the nut region of a male coupling, and a second annular ring has a keyed opening sized to fit around the nut of a female coupling. Each ring has mating ratchet teeth and these rings are biased together, thereby engaging these teeth and preventing rotation of these rings. This in turn prevents the rotation of the male nut region with respect to the female nut. For tube-to-bulkhead locking, one facet of one ring is notched, and a pin is pressed into an opening in the bulkhead. This pin is sized to fit within one of the notches in the ring, thereby preventing rotation of this ring with respect to the bulkhead

    The Press, the Academy, and FOIA

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    PHP22 Are Hospital Medicines Prices Influenced by Discounts and Rebates?

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    Control of bacterial population density with population feedback and molecular sequestration

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    Genetic engineering technology has become sophisticated enough to allow precise manipulation of bacterial genetic material. Engineering efforts with these technologies have created modified bacteria for various medical, industrial, and environmental purposes, but organisms designed for specific functions require improvements in stability, longevity, or efficiency of function. Most bacteria live in multispecies communities, whose composition may be closely linked to the effect the community has on the environment. Bacterial engineering efforts will benefit from building communities with regulated compositions, which will enable more stable and powerful community functions. We present a design of a synthetic two member bacterial community capable of maintaining its composition at a defined ratio of [cell type 1] : [cell type 2]. We have constructed the genetic motif that will act in each cell in the two member community, containing an AHL-based negative feedback loop that activates ccdB toxin, which caps population density with increasing feedback strength. It also contains one of two ccdB sequestration modules, either the ccdA protein antitoxin, or an RNA device which prevents transcription and translation of ccdB mRNA, that rescues capped population density with induction. We compare absorbance and colony counting methods of estimating bacterial population density, finding that absorbance-based methods overestimate viable population density when ccdB toxin is used to control population density. Prior modeling results show that two cell types containing this genetic circuit motif that reciprocally activate the other's ccdB sequestration device will establish a steady state ratio of cell types. Experimental testing and tuning the full two member community will help us improve our modeling of multi-member bacterial communities, learn more about the strengths and weaknesses of our design for community composition control, and identify general principles of design of compositionally-regulated microbial communities

    Engineering Logical Inflammation Sensing Circuit for Modulating Gut Conditions

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    The mammalian gut contains trillions of microbes that interact with host cells and monitor changes in the environment. Opportunistic pathogens exploit environmental conditions to stimulate their growth and virulence, leading to a resurgence of chronic disorders such as inflammatory bowel disease (IBD). Current therapies are effective in less than 30% of patients due to the lack of adherence to prescription schedules and overall, off-target effects. Smart microbial therapeutics can be engineered to colonize the gut, providing in situ surveillance and conditional disease modulation. However, many current engineered microbes can only respond to single gut environmental factors, limiting their effectiveness. In this work, we implement the previously characterized split activator AND logic gate in the probiotic E. coli strain Nissle 1917. Our system can respond to two input signals: the inflammatory biomarker tetrathionate and a second input signal, IPTG. We report 4-6 fold induction with minimal leak when both signals are present. We model the dynamics of the AND gate using chemical reaction networks, and by tuning parameters in silico, we identified perturbations that affect our circuit's selectivity. We anticipate that our results will prove useful for designing living therapeutics for spatial targeting and signal processing in complex environments

    How native state topology affects the folding of Dihydrofolate Reductase and Interleukin-1beta

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    The overall structure of the transition state and intermediate ensembles experimentally observed for Dihydrofolate Reductase and Interleukin-1beta can be obtained utilizing simplified models which have almost no energetic frustration. The predictive power of these models suggest that, even for these very large proteins with completely different folding mechanisms and functions, real protein sequences are sufficiently well designed and much of the structural heterogeneity observed in the intermediates and the transition state ensembles is determined by topological effects.Comment: Proc. Natl. Acad. Sci. USA, in press (11 pages, 4 color PS figures) Higher resolution PS files can be found at http://www-physics.ucsd.edu/~cecilia/pub_list.htm

    Pengaruh Waktu Pengeringan Dan Tempering Terhadap Mutu Beras Pada Pengeringan Gabah Lapisan Tipis

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    The aim of this research was to determine the effect of various drying and tempering durations on rice quality using thin layer drying. The drying procedure consist four satge; first rough rice was dried in a drying chamber for various durations to remove 5 to 8 % moisture content (M.C). In the second stage rice was tempered under the room temperature for certain duration, to reduce MC gradients within the kernels. tempering period. The rice was then dried further to reach the final 14 % M.C. After the second drying the rice was tempered. Drying process was conducted using  heated air at temperature of either 50 0C, RH 26%  or  60 0C, RH 17%. The results  show that very small  reduction in Head Rice Yield (HRY) when  less than 6 % m.c, were removed during the first drying stage. Effects on HRY was obeserved when the moisture removal was greater than 6% m.c. during the 1st drying stage. It was also observed that tempering time could not prevent the reduction in HRY when moisture remomal was higher than 6% M.C. during the 1st drying stage

    The impact of approaches in improving male partner involvement in the prevention of mother-to-child transmission of HIV on the uptake of safe infant feeding practices by HIV positive women in sub-Saharan Africa. A systematic review and meta-analysis.

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    BACKGROUND: The low level of male partner involvement in Prevention of Mother to Child Transmission of HIV services such as safe infant feeding practices poses a serious challenge to the implementation of guidelines on safe infant feeding and may undermine efforts towards elimination of mother to child transmission of HIV in sub Saharan Africa(SSA). We conducted a systematic review and meta-analysis to identify the approaches that have been utilized to improve male partner involvement in PMTCT services as well as their impact on the uptake of safe infant feeding practices by HIV positive mothers in SSA. METHODS: In this systematic review and meta-analysis, Ovid Medline, Embase, PsycINFO, Cochrane library, ClinicalTrials.gov, Web of Science and Current Controlled Trials were searched. Only studies performed in SSA that reported an approach that specifically involved male partners and its impact on the uptake of safe infant feeding practices (irrespective of the language and date of publication) were included. Odds ratios were extracted or calculated from studies and combined in a meta-analysis using the statistical package Stata version 11.0. Forest plots were generated using the random effect model. RESULTS: From an initial 2416 non-duplicate articles, 06 articles were included in the systematic review and meta-analysis. The overall pooled unadjusted OR was 3.08[95%CI: 2.58-3.68], while the effect sizes for interventions aimed at promoting male partner involvement such as verbal encouragement, complex community intervention and enhanced psychosocial interventions were 1.93[95%CI: 1.34-2.79], 3.45[95%CI: 2.79-4.25] and 5.14[95%CI: 2.42-10.90] respectively. Using only adjusted odd ratios, the pooled adjusted OR = 1.78[95%CI: 1.35-2.34]. The I2 = 60.1% p = 0.057 using adjusted ORs. CONCLUSION: Interventions aimed at promoting male partner involvement such as enhanced psychosocial interventions, verbal encouragement and complex community interventions increase the uptake of safe infant feeding options. The heterogeneity was moderate among studies. More studies including randomised trials that will recruit larger, representative samples of patients are needed in the future. Prospero registration number: 42016032673

    Ideally embedded space-times

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    Due to the growing interest in embeddings of space-time in higher-dimensional spaces we consider a specific type of embedding. After proving an inequality between intrinsically defined curvature invariants and the squared mean curvature, we extend the notion of ideal embeddings from Riemannian geometry to the indefinite case. Ideal embeddings are such that the embedded manifold receives the least amount of tension from the surrounding space. Then it is shown that the de Sitter spaces, a Robertson-Walker space-time and some anisotropic perfect fluid metrics can be ideally embedded in a five-dimensional pseudo-Euclidean space.Comment: layout changed and typos corrected; uses revtex
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