252 research outputs found

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    Recommendations for Practitioners Engaged in Antitrafficking Task Forces: An Evalaution of the Enhanced Collaborative Model Task Forces to Combat Human Trafficking

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    The Enhanced Collaborative Model (ECM) Task Force to Combat Human Trafficking Program funded task forces comprised of law enforcement officials, prosecutors, victim service providers, and other stakeholders at the local, state, and federal levels. This brief details recommendations from the Urban Institute's 10-site evaluation of ECM task forces across the United States. Recommendations were derived from the findings of our analysis and directly from task force stakeholders' responses to interview questions about task force recommendations and best practices. Respondents summarized recommendations across four categories including structure, operation, and funding of ECM task forces; collaboration among stakeholders; survivor engagement and service provision; and task force training, focus, and activities

    E. coli catheter-associated urinary tract infections are associated with distinctive virulence and biofilm gene determinants

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    Urinary catheterization facilitates urinary tract colonization by E. coli and increases infection risk. Here, we aimed to identify strain-specific characteristics associated with the transition from colonization to infection in catheterized patients. In a single-site study population, we compared E. coli isolates from patients with catheter-associated asymptomatic bacteriuria (CAASB) to those with catheter-associated urinary tract infection (CAUTI). CAUTI isolates were dominated by a phylotype B2 subclade containing the multidrug-resistant ST131 lineage relative to CAASB isolates, which were phylogenetically more diverse. A distinctive combination of virulence-associated genes was present in the CAUTI-associated B2 subclade. Catheter-associated biofilm formation was widespread among isolates and did not distinguish CAUTI from CAASB strains. Preincubation with CAASB strains could inhibit catheter colonization by multiple ST131 CAUTI isolates. Comparative genomic analysis identified a group of variable genes associated with high catheter biofilm formation present in both CAUTI and CAASB strains. Among these, ferric citrate transport (Fec) system genes were experimentally associated with enhanced catheter biofilm formation using reporter and fecA deletion strains. These results are consistent with a variable role for catheter biofilm formation in promoting CAUTI by ST131-like strains or resisting CAUTI by lower-risk strains that engage in niche exclusion

    Cash vs. food assistance to improve adherence to antiretroviral therapy among HIV-infected adults in Tanzania.

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    OBJECTIVE: We evaluated the effectiveness of short-term cash and food assistance to improve adherence to antiretroviral therapy (ART) and retention in care among people living with HIV in Tanzania. METHODS: At three clinics, 805 participants were randomized to three groups in a 3 : 3 : 1 ratio, stratified by site : nutrition assessment and counseling (NAC) and cash transfers (∼$11/month, n = 347), NAC and food baskets (n = 345), and NAC-only (comparison group, n = 113, clinicaltrials.gov NCT01957917). Eligible people living with HIV were at least 18 years, initiated ART 90 days or less prior, and food insecure. Cash or food was provided for 6 or less consecutive months, conditional on visit attendance. The primary outcome was medication possession ratio (MPR ≥ 95%) at 6 months. Secondary outcomes were appointment attendance and loss to follow-up (LTFU) at 6 and 12 months. RESULTS: The primary intent-to-treat analysis included 800 participants. Achievement of MPR ≥ 95% at 6 months was higher in the NAC + cash group compared with NAC-only (85.0 vs. 63.4%), a 21.6 percentage point difference [95% confidence interval (CI): 9.8, 33.4, P < 0.01]. MPR ≥ 95% was also significantly higher in the NAC + food group vs. NAC-only (difference = 15.8, 95% CI: 3.8, 27.9, P < 0.01). When directly compared, MPR ≥ 95% was similar in the NAC + cash and NAC + food groups (difference = 5.7, 95% CI: -1.2, 12.7, P = 0.15). Compared with NAC-only, appointment attendance and LTFU were significantly higher in both the NAC + cash and NAC + food groups at 6 months. At 12 months, the effect of NAC + cash, but not NAC + food, on MPR ≥ 95% and retention was sustained. CONCLUSION: Short-term conditional cash and food assistance improves ART possession and appointment attendance and reduces LTFU among food-insecure ART initiates in Tanzania

    Polynomial Identities, Indices, and Duality for the N=1 Superconformal Model SM(2,4\nu)

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    We prove polynomial identities for the N=1 superconformal model SM(2,4\nu) which generalize and extend the known Fermi/Bose character identities. Our proof uses the q-trinomial coefficients of Andrews and Baxter on the bosonic side and a recently introduced very general method of producing recursion relations for q-series on the fermionic side. We use these polynomials to demonstrate a dual relation under q \rightarrow q^{-1} between SM(2,4\nu) and M(2\nu-1,4\nu). We also introduce a generalization of the Witten index which is expressible in terms of the Rogers false theta functions.Comment: 41 pages, harvmac, no figures; new identities, proofs and comments added; misprints eliminate

    Capturing Hammerhead Ribozyme Structures in Action by Modulating General Base Catalysis

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    We have obtained precatalytic (enzyme–substrate complex) and postcatalytic (enzyme–product complex) crystal structures of an active full-length hammerhead RNA that cleaves in the crystal. Using the natural satellite tobacco ringspot virus hammerhead RNA sequence, the self-cleavage reaction was modulated by substituting the general base of the ribozyme, G12, with A12, a purine variant with a much lower pKa that does not significantly perturb the ribozyme's atomic structure. The active, but slowly cleaving, ribozyme thus permitted isolation of enzyme–substrate and enzyme–product complexes without modifying the nucleophile or leaving group of the cleavage reaction, nor any other aspect of the substrate. The predissociation enzyme-product complex structure reveals RNA and metal ion interactions potentially relevant to transition-state stabilization that are absent in precatalytic structures

    Financial incentives to promote retention in care and viral suppression in adults with HIV initiating antiretroviral therapy in Tanzania: a three-arm randomised controlled trial

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    Background: Financial incentives promote use of HIV services and might support adherence to the sustained antiretroviral therapy (ART) necessary for viral suppression, but few studies have assessed a biomarker of adherence or evaluated optimal implementation. We sought to determine whether varying sized financial incentives for clinic attendance effected viral suppression in patients starting ART in Tanzania. Methods: In a three-arm, parallel-group, randomised controlled trial at four health facilities in Shinyanga region, Tanzania, adults aged 18 years or older with HIV who had started ART within the past 30 days were randomly assigned (1:1:1) using a tablet-based application (stratified by site) to receive usual care (control group) or to receive a cash incentive for monthly clinic attendance in one of two amounts: 10 000 Tanzanian Shillings (TZS; about US450)or22500TZS(about4·50) or 22 500 TZS (about 10·00). There were no formal exclusion criteria. Participants were masked to the existence of two incentive sizes. Incentives were provided for up to 6 months via mobile health technology (mHealth) that linked biometric attendance monitoring to automated mobile payments. We evaluated the primary outcome of retention in care with viral suppression (<1000 copies per mL) at 6 months using logistic regression. This trial is registered with ClinicalTrials.gov, NCT03351556. Findings: Between April 24 and Dec 14, 2018, 530 participants were randomly assigned to an incentive strategy (184 in the control group, 172 in the smaller incentive group, and 174 in the larger incentive group). All participants were included in the primary intention-to-treat analysis. At 6 months, approximately 134 (73%) participants in the control group remained in care and had viral suppression, compared with 143 (83%) in the smaller incentive group (risk difference [RD] 9·8, 95% CI 1·2 to 18·5) and 150 (86%) in the larger incentive group (RD 13·0, 4·5 to 21·5); we identified a positive trend between incentive size and viral suppression (p trend=0·0032), although the incentive groups did not significantly differ (RD 3·2, −4·6 to 11·0). Adverse events included seven (4%) deaths in the control group and 11 (3%) deaths in the intervention groups, none related to study participation. Interpretation: Small financial incentives delivered using mHealth can improve retention in care and viral suppression in adults starting HIV treatment. Although further research should investigate the durability of effects from short-term incentives, these findings strengthen the evidence for implementing financial incentives within standard HIV care

    Structure of an Engineered β-Lactamase Maltose Binding Protein Fusion Protein: Insights into Heterotropic Allosteric Regulation

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    Engineering novel allostery into existing proteins is a challenging endeavor to obtain novel sensors, therapeutic proteins, or modulate metabolic and cellular processes. The RG13 protein achieves such allostery by inserting a circularly permuted TEM-1 β-lactamase gene into the maltose binding protein (MBP). RG13 is positively regulated by maltose yet is, serendipitously, inhibited by Zn2+ at low µM concentration. To probe the structure and allostery of RG13, we crystallized RG13 in the presence of mM Zn2+ concentration and determined its structure. The structure reveals that the MBP and TEM-1 domains are in close proximity connected via two linkers and a zinc ion bridging both domains. By bridging both TEM-1 and MBP, Zn2+ acts to “twist tie” the linkers thereby partially dislodging a linker between the two domains from its original catalytically productive position in TEM-1. This linker 1 contains residues normally part of the TEM-1 active site including the critical β3 and β4 strands important for activity. Mutagenesis of residues comprising the crystallographically observed Zn2+ site only slightly affected Zn2+ inhibition 2- to 4-fold. Combined with previous mutagenesis results we therefore hypothesize the presence of two or more inter-domain mutually exclusive inhibitory Zn2+ sites. Mutagenesis and molecular modeling of an intact TEM-1 domain near MBP within the RG13 framework indicated a close surface proximity of the two domains with maltose switching being critically dependent on MBP linker anchoring residues and linker length. Structural analysis indicated that the linker attachment sites on MBP are at a site that, upon maltose binding, harbors both the largest local Cα distance changes and displays surface curvature changes, from concave to relatively flat becoming thus less sterically intrusive. Maltose activation and zinc inhibition of RG13 are hypothesized to have opposite effects on productive relaxation of the TEM-1 β3 linker region via steric and/or linker juxtapositioning mechanisms

    Structural basis for type VI secreted peptidoglycan DL-endopeptidase function, specificity and neutralization in <em>Serratia marcescens</em>

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    Some Gram-negative bacteria target their competitors by exploiting the type VI secretion system to extrude toxic effector proteins. To prevent self-harm, these bacteria also produce highly specific immunity proteins that neutralize these antagonistic effectors. Here, the peptidoglycan endopeptidase specificity of two type VI secretion-system-associated effectors from Serratia marcescens is characterized. These small secreted proteins, Ssp1 and Ssp2, cleave between γ-d-glutamic acid and l-meso-diaminopimelic acid with different specificities. Ssp2 degrades the acceptor part of cross-linked tetratetrapeptides. Ssp1 displays greater promiscuity and cleaves monomeric tripeptides, tetrapeptides and pentapeptides and dimeric tetratetra and tetrapenta muropeptides on both the acceptor and donor strands. Functional assays confirm the identity of a catalytic cysteine in these endopeptidases and crystal structures provide information on the structure–activity relationships of Ssp1 and, by comparison, of related effectors. Functional assays also reveal that neutralization of these effectors by their cognate immunity proteins, which are called resistance-associated proteins (Raps), contributes an essential role to cell fitness. The structures of two immunity proteins, Rap1a and Rap2a, responsible for the neutralization of Ssp1 and Ssp2-like endopeptidases, respectively, revealed two distinct folds, with that of Rap1a not having previously been observed. The structure of the Ssp1–Rap1a complex revealed a tightly bound heteromeric assembly with two effector molecules flanking a Rap1a dimer. A highly effective steric block of the Ssp1 active site forms the basis of effector neutralization. Comparisons with Ssp2–Rap2a orthologues suggest that the specificity of these immunity proteins for neutralizing effectors is fold-dependent and that in cases where the fold is conserved sequence differences contribute to the specificity of effector–immunity protein interactions

    Structure-Based Exploration and Exploitation of the S4 Subsite of Norovirus 3CL Protease in the Design of Potent and Permeable Inhibitors

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    Human noroviruses are the primary cause of epidemic and sporadic acute gastroenteritis. The worldwide high morbidity and mortality associated with norovirus infections, particularly among the elderly, immunocompromised patients and children, constitute a serious public health concern. There are currently no approved human vaccines or norovirus-specific small-molecule therapeutics or prophylactics. Norovirus 3CL protease has recently emerged as a potential therapeutic target for the development of anti-norovirus agents. We hypothesized that the S4 subsite of the enzyme may provide an effective means of designing potent and cell permeable inhibitors of the enzyme. We report herein the structure-guided exploration and exploitation of the S4 subsite of norovirus 3CL protease in the design and synthesis of effective inhibitors of the protease
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