266 research outputs found
Accuracy of Name and Age Data Provided About Network Members in a Social Network Study of People Who Use Drugs: Implications for Constructing Sociometric Networks
Purpose—Network analysis has become increasingly popular in epidemiologic research, but the accuracy of data key to constructing risk networks is largely unknown. Using network data from people who use drugs (PWUD), the study examined how accurately PWUD reported their network members’ (i.e., alters’) names and ages.
Methods—Data were collected from 2008 to 2010 from 503 PWUD residing in rural Appalachia. Network ties (n=897) involved recent (past 6 months) sex, drug co-usage, and/or social support. Participants provided alters’ names, ages, and relationship-level characteristics; these data were cross-referenced to that of other participants to identify participant-participant relationships and to determine the accuracy of reported ages (years) and names (binary).
Results—Participants gave alters’ exact names and ages within two years in 75% and 79% of relationships, respectively. Accurate name was more common in relationships that were reciprocally reported and those involving social support and male alters. Age was more accurate in reciprocal ties and those characterized by kinship, sexual partnership, recruitment referral, and financial support, and less accurate for ties with older alters.
Conclusions—Most participants reported alters’ characteristics accurately, and name accuracy was not significantly different in relationships involving drug-related/sexual behavior compared to those not involving these behaviors
L-5-methyltetrahydrofolate supplementation increases blood folate concentrations to a greater extent than folic acid supplementation in Malaysian women
Background: Folic acid fortification of grains is mandated in many countries to prevent neural tube defects. Concerns regarding excessive intakes of folic acid have been raised. A synthetic analog of the circulating form of folate, l-5-methyltetrahydrofolate (l-5-MTHF), may be a potential alternative. Objective: The objective of this study was to determine the effects of folic acid or l-5-MTHF supplementation on blood folate concentrations, methyl nutrient metabolites, and DNA methylation in women living in Malaysia, where there is no mandatory fortification policy. Methods: In a 12-wk, randomized, placebo-controlled intervention trial, healthy Malaysian women (n = 142, aged 20–45 y) were randomly assigned to receive 1 of the following supplements daily: 1 mg (2.27 μmol) folic acid, 1.13 mg (2.27 μmol) l-5-MTHF, or a placebo. The primary outcomes were plasma and RBC folate and vitamin B-12 concentrations. Secondary outcomes included plasma total homocysteine, total cysteine, methionine, betaine, and choline concentrations and monocyte long interspersed nuclear element-1 (LINE-1) methylation. Results: The folic acid and l-5-MTHF groups had higher (P < 0.001) RBC folate (mean ± SD: 1498 ± 580 and 1951 ± 496 nmol/L, respectively) and plasma folate [median (25th, 75th percentiles): 40.1 nmol/L (24.9, 52.7 nmol/L) and 52.0 nmol/L (42.7, 73.1 nmol/L), respectively] concentrations compared with RBC folate (958 ± 345 nmol/L) and plasma folate [12.6 nmol/L (8.80, 17.0 nmol/L)] concentrations in the placebo group at 12 wk. The l-5-MTHF group had higher RBC folate (1951 ± 496 nmol/L; P = 0.003) and plasma folate [52.0 nmol/L (42.7, 73.1 nmol/L); P = 0.023] at 12 wk than did the folic acid group [RBC folate, 1498 ± 580 nmol/L; plasma folate, 40.1 nmol/L (24.9, 52.7 nmol/L)]. The folic acid and l-5-MTHF groups had 17% and 15%, respectively, lower (P < 0.001) plasma total homocysteine concentrations than did the placebo group at 12 wk; there were no differences between the folic acid and l-5-MTHF groups. No differences in plasma vitamin B-12, total cysteine, methionine, betaine, and choline and monocyte LINE-1 methylation were observed. Conclusion: These findings suggest differential effects of l-5-MTHF compared with folic acid supplementation on blood folate concentrations but no differences on plasma total homocysteine lowering in Malaysian women. This trial was registered at clinicaltrials.gov as NCT01584050
HIV, Tuberculosis, and Non-Communicable Diseases: what is known about the costs, effects, and cost-effectiveness of integrated care?
CAPRISA, 2014.Abstract available in pdf
Pacific Northwest National Laboratory Site Environmental Report for Calendar Year 2011
The PNNL Site Environmental Report for Calendar Year 2011 was prepared pursuant to the requirements of Department of Energy (DOE) Order 231.1B, "Environment, Safety and Health Reporting" to provide a synopsis of calendar year 2011 information related to environmental management performance and compliance efforts. It summarizes site compliance with federal, state, and local environmental laws, regulations, policies, directives, permits, and orders and environmental management performance
The Clinical and Economic Impact of Point-of-Care CD4 Testing in Mozambique and Other Resource-Limited Settings: A Cost-Effectiveness Analysis
Background: Point-of-care CD4 tests at HIV diagnosis could improve linkage to care in resource-limited settings. Our objective is to evaluate the clinical and economic impact of point-of-care CD4 tests compared to laboratory-based tests in Mozambique. Methods and Findings: We use a validated model of HIV testing, linkage, and treatment (CEPAC-International) to examine two strategies of immunological staging in Mozambique: (1) laboratory-based CD4 testing (LAB-CD4) and (2) point-of-care CD4 testing (POC-CD4). Model outcomes include 5-y survival, life expectancy, lifetime costs, and incremental cost-effectiveness ratios (ICERs). Input parameters include linkage to care (LAB-CD4, 34%; POC-CD4, 61%), probability of correctly detecting antiretroviral therapy (ART) eligibility (sensitivity: LAB-CD4, 100%; POC-CD4, 90%) or ART ineligibility (specificity: LAB-CD4, 100%; POC-CD4, 85%), and test cost (LAB-CD4, US24). In sensitivity analyses, we vary POC-CD4-specific parameters, as well as cohort and setting parameters to reflect a range of scenarios in sub-Saharan Africa. We consider ICERs less than three times the per capita gross domestic product in Mozambique (US2,440 (95% CI, US2,450) and increase with POC-CD4 to 10.3 y (95% CI, 10.3–10.3 y) and US2,790–US500/year of life saved (YLS) (95% CI, US520/YLS). POC-CD4 improves clinical outcomes and remains near the very cost-effective threshold in sensitivity analyses, even if point-of-care CD4 tests have lower sensitivity/specificity and higher cost than published values. In other resource-limited settings with fewer opportunities to access care, POC-CD4 has a greater impact on clinical outcomes and remains cost-effective compared to LAB-CD4. Limitations of the analysis include the uncertainty around input parameters, which is examined in sensitivity analyses. The potential added benefits due to decreased transmission are excluded; their inclusion would likely further increase the value of POC-CD4 compared to LAB-CD4. Conclusions: POC-CD4 at the time of HIV diagnosis could improve survival and be cost-effective compared to LAB-CD4 in Mozambique, if it improves linkage to care. POC-CD4 could have the greatest impact on mortality in settings where resources for HIV testing and linkage are most limited. Please see later in the article for the Editors' Summar
The clinical and economic impact of point-of-care CD4 testing in Mozambique and other resource-limited settings: a cost-effectiveness analysis
Emily Hyle and colleagues conduct a cost-effectiveness analysis to estimate the clinical and economic impact of point-of-care CD4 testing compared to laboratory-based tests in Mozambique. Please see later in the article for the Editors' Summar
High-fidelity operation and algorithmic initialisation of spin qubits above one kelvin
The encoding of qubits in semiconductor spin carriers has been recognised as
a promising approach to a commercial quantum computer that can be
lithographically produced and integrated at scale. However, the operation of
the large number of qubits required for advantageous quantum applications will
produce a thermal load exceeding the available cooling power of cryostats at
millikelvin temperatures. As the scale-up accelerates, it becomes imperative to
establish fault-tolerant operation above 1 kelvin, where the cooling power is
orders of magnitude higher. Here, we tune up and operate spin qubits in silicon
above 1 kelvin, with fidelities in the range required for fault-tolerant
operation at such temperatures. We design an algorithmic initialisation
protocol to prepare a pure two-qubit state even when the thermal energy is
substantially above the qubit energies, and incorporate high-fidelity
radio-frequency readout to achieve an initialisation fidelity of 99.34 per
cent. Importantly, we demonstrate a single-qubit Clifford gate fidelity of
99.85 per cent, and a two-qubit gate fidelity of 98.92 per cent. These advances
overcome the fundamental limitation that the thermal energy must be well below
the qubit energies for high-fidelity operation to be possible, surmounting a
major obstacle in the pathway to scalable and fault-tolerant quantum
computation
Consistency of high-fidelity two-qubit operations in silicon
The consistency of entangling operations between qubits is essential for the
performance of multi-qubit systems, and is a crucial factor in achieving
fault-tolerant quantum processors. Solid-state platforms are particularly
exposed to inconsistency due to the materials-induced variability of
performance between qubits and the instability of gate fidelities over time.
Here we quantify this consistency for spin qubits, tying it to its physical
origins, while demonstrating sustained and repeatable operation of two-qubit
gates with fidelities above 99% in the technologically important silicon
metal-oxide-semiconductor (SiMOS) quantum dot platform. We undertake a detailed
study of the stability of these operations by analysing errors and fidelities
in multiple devices through numerous trials and extended periods of operation.
Adopting three different characterisation methods, we measure entangling gate
fidelities ranging from 96.8% to 99.8%. Our analysis tools also identify
physical causes of qubit degradation and offer ways to maintain performance
within tolerance. Furthermore, we investigate the impact of qubit design,
feedback systems, and robust gates on implementing scalable, high-fidelity
control strategies. These results highlight both the capabilities and
challenges for the scaling up of spin-based qubits into full-scale quantum
processors
Boron Nitride Nanotube: Synthesis and Applications
Scientists have predicted that carbon's immediate neighbors on the periodic chart, boron and nitrogen, may also form perfect nanotubes, since the advent of carbon nanotubes (CNTs) in 1991. First proposed then synthesized by researchers at UC Berkeley in the mid 1990's, the boron nitride nanotube (BNNT) has proven very difficult to make until now. Herein we provide an update on a catalyst-free method for synthesizing highly crystalline, small diameter BNNTs with a high aspect ratio using a high power laser under a high pressure and high temperature environment first discovered jointly by NASA/NIA JSA. Progress in purification methods, dispersion studies, BNNT mat and composite formation, and modeling and diagnostics will also be presented. The white BNNTs offer extraordinary properties including neutron radiation shielding, piezoelectricity, thermal oxidative stability (> 800 C in air), mechanical strength, and toughness. The characteristics of the novel BNNTs and BNNT polymer composites and their potential applications are discussed
HER2-Specific Chimeric Antigen Receptor–Modified Virus-Specific T Cells for Progressive Glioblastoma: A Phase 1 Dose-Escalation Trial
Glioblastoma is an incurable tumor, and the therapeutic options for patients are limited. To determine whether the systemic administration of HER2-specific chimeric antigen receptor (CAR)-modified virus-specific T cells (VSTs) is safe and whether these cells have antiglioblastoma activity. In this open-label phase 1 dose-escalation study conducted at Baylor College of Medicine, Houston Methodist Hospital, and Texas Children's Hospital, patients with progressive HER2-positive glioblastoma were enrolled between July 25, 2011, and April 21, 2014. The duration of follow-up was 10 weeks to 29 months (median, 8 months). Monotherapy with autologous VSTs specific for cytomegalovirus, Epstein-Barr virus, or adenovirus and genetically modified to express HER2-CARs with a CD28.ζ-signaling endodomain (HER2-CAR VSTs). Primary end points were feasibility and safety. The key secondary end points were T-cell persistence and their antiglioblastoma activity. A total of 17 patients (8 females and 9 males; 10 patients ≥18 years [median age, 60 years; range, 30-69 years] and 7 patients <18 years [median age, 14 years; range, 10-17 years]) with progressive HER2-positive glioblastoma received 1 or more infusions of autologous HER2-CAR VSTs (1 × 106/m2 to 1 × 108/m2) without prior lymphodepletion. Infusions were well tolerated, with no dose-limiting toxic effects. HER2-CAR VSTs were detected in the peripheral blood for up to 12 months after the infusion by quantitative real-time polymerase chain reaction. Of 16 evaluable patients (9 adults and 7 children), 1 had a partial response for more than 9 months, 7 had stable disease for 8 weeks to 29 months, and 8 progressed after T-cell infusion. Three patients with stable disease are alive without any evidence of progression during 24 to 29 months of follow-up. For the entire study cohort, median overall survival was 11.1 months (95% CI, 4.1-27.2 months) from the first T-cell infusion and 24.5 months (95% CI, 17.2-34.6 months) from diagnosis. Infusion of autologous HER2-CAR VSTs is safe and can be associated with clinical benefit for patients with progressive glioblastoma. Further evaluation of HER2-CAR VSTs in a phase 2b study is warranted as a single agent or in combination with other immunomodulatory approaches for glioblastoma
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