Objectives To assess diagnostic accuracy of screening tests for pre-diabetes and efficacy of interventions (lifestyle or metformin) in preventing onset of type 2 diabetes in people with ...pre-diabetes.Design Systematic review and meta-analysis.Data sources and method Medline, PreMedline, and Embase. Study protocols and seminal papers were citation-tracked in Google Scholar to identify definitive trials and additional publications. Data on study design, methods, and findings were extracted onto Excel spreadsheets; a 20% sample was checked by a second researcher. Data extracted for screening tests included diagnostic accuracy and population prevalence. Two meta-analyses were performed, one summarising accuracy of screening tests (with the oral glucose tolerance test as the standard) for identification of pre-diabetes, and the other assessing relative risk of progression to type 2 diabetes after either lifestyle intervention or treatment with metformin.Eligibility criteria Empirical studies evaluating accuracy of tests for identification of pre-diabetes. Interventions (randomised trials and interventional studies) with a control group in people identified through screening. No language restrictions.Results 2874 titles were scanned and 148 papers (covering 138 studies) reviewed in full. The final analysis included 49 studies of screening tests (five of which were prevalence studies) and 50 intervention trials. HbA1c had a mean sensitivity of 0.49 (95% confidence interval 0.40 to 0.58) and specificity of 0.79 (0.73 to 0.84), for identification of pre-diabetes, though different studies used different cut-off values. Fasting plasma glucose had a mean sensitivity of 0.25 (0.19 to 0.32) and specificity of 0.94 (0.92 to 0.96). Different measures of glycaemic abnormality identified different subpopulations (for example, 47%of people with abnormal HbA1c had no other glycaemic abnormality). Lifestyle interventions were associated with a 36% (28% to 43%) reduction in relative risk of type 2 diabetes over six months to six years, attenuating to 20% (8% to 31%) at follow-up in the period after the trails.Conclusions HbA1c is neither sensitive nor specific for detecting pre-diabetes; fasting glucose is specific but not sensitive. Interventions in people classified through screening as having pre-diabetes have some efficacy in preventing or delaying onset of type 2 diabetes in trial populations. As screening is inaccurate, many people will receives an incorrect diagnosis and be referred on for interventions while others will be falsely reassured and not offered the intervention. These findings suggest that “screen and treat” policies alone are unlikely to have substantial impact on the worsening epidemic of type 2 diabetes.Registration PROSPERO (No CRD42016042920).
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BFBNIB, CMK, NMLJ, NUK, PNG, SAZU, UL, UM, UPUK
Examining non-sport-related cognitive tasks of attention and executive control in skilled athletes may provide insight into the acquisition of highly specific skills developed in experts as well as ...help identify successful performance in sport. Through a cross-sectional design, this study examined performance on aspects of attention and executive control among varsity athletes playing soccer (strategic sport) or track & field (static sport) using a computerized test of attention and executive control. Ninety-seven university athletes participating in soccer (n = 50) or track and field (n = 47) were included in the study. Domains of attention and executive control were examined using the Attention Network Test-Interactions (ANT-I). Mean reaction time (RT) and intra-individual variability (IIV) were compared between groups as measures of performance speed and performance stability respectively. Soccer players demonstrated overall faster RTs (p = 0.0499; ηp2 = .04) and higher response accuracy (p = .021, d = .48) on the ANT-I compared to track and field athletes. Faster RTs were observed for soccer players when presented with an alerting tone (p = .029, d = .45), valid orienting cue (p = .019, d = .49) and incongruent flanker (p = .031, d = .45). No significant group differences were observed in IIV (p = .083, d = .36). Athletes engaging in strategic sports (i.e., soccer) demonstrated faster performance under test conditions that required higher vigilance and conflict resolution. These findings suggest that engagement in strategic sports is associated with enhanced performance on non-sport-related cognitive tasks of attention and executive control.
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DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
3.
Graphene kirigami Blees, Melina K; Barnard, Arthur W; Rose, Peter A ...
Nature (London),
08/2015, Volume:
524, Issue:
7564
Journal Article
Peer reviewed
For centuries, practitioners of origami ('ori', fold; 'kami', paper) and kirigami ('kiru', cut) have fashioned sheets of paper into beautiful and complex three-dimensional structures. Both techniques ...are scalable, and scientists and engineers are adapting them to different two-dimensional starting materials to create structures from the macro- to the microscale. Here we show that graphene is well suited for kirigami, allowing us to build robust microscale structures with tunable mechanical properties. The material parameter crucial for kirigami is the Föppl-von Kármán number γ: an indication of the ratio between in-plane stiffness and out-of-plane bending stiffness, with high numbers corresponding to membranes that more easily bend and crumple than they stretch and shear. To determine γ, we measure the bending stiffness of graphene monolayers that are 10-100 micrometres in size and obtain a value that is thousands of times higher than the predicted atomic-scale bending stiffness. Interferometric imaging attributes this finding to ripples in the membrane that stiffen the graphene sheets considerably, to the extent that γ is comparable to that of a standard piece of paper. We may therefore apply ideas from kirigami to graphene sheets to build mechanical metamaterials such as stretchable electrodes, springs, and hinges. These results establish graphene kirigami as a simple yet powerful and customizable approach for fashioning one-atom-thick graphene sheets into resilient and movable parts with microscale dimensions.
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Current silicon photonics phased arrays based on waveguide gratings enable beam steering with no moving parts. However, they suffer from a trade-off between beam divergence and field of view. Here, ...we show a platform based on silicon-nitride/silicon that achieves simultaneously minimal beam divergence and maximum field of view while maintaining performance that is robust to fabrication variations. In addition, in order to maximize the emission from the entire length of the grating, we design the grating's strength by varying its duty cycle (apodization) to emit uniformly. We fabricate a millimeter long grating emitter with diffraction-limited beam divergence of 0.089°.
HIV‐1 enters the brain by altering properties of the blood‐brain barrier (BBB). Recent evidence indicates that among cells of the BBB, pericytes are prone to HIV‐1 infection. Occludin (ocln) and ...caveolin‐1 (cav‐1) are critical determinants of BBB integrity that can regulate barrier properties of the BBB in response to HIV‐1 infection. Additionally, Alix is an early acting endosomal factor involved in HIV‐1 budding from the cells. The aim of the present study was to evaluate the role of cav‐1, ocln, and Alix in HIV‐1 infection of brain pericytes. Our results indicated that cav‐1, ocln, and Alix form a multi‐protein complex in which they cross‐regulate each other's expression. Importantly, the stability of this complex was affected by HIV‐1 infection. Modifications of the complex resulted in diminished HIV‐1 infection and alterations of the cytokine profile produced by brain pericytes. These results identify a novel mechanism involved in HIV‐1 infection contributing to a better understanding of the HIV‐1 pathology and the associated neuroinflammatory responses.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SAZU, SBCE, SBMB, UL, UM, UPUK
On-chip resonators are promising candidates for applications in a wide range of integrated photonic fields, such as communications, spectroscopy, biosensing, and optical filters, due to their compact ...size, wavelength selectivity, tunability, and flexible structure. The high quality (Q) factor is a main positive attribute of on-chip resonators that makes it possible for them to provide high sensitivity, narrow bandpass, and low power consumption. In this Tutorial, we discuss methods to achieve ultra-high Q factor on-chip resonators on a silicon nitride (Si3N4) platform. We outline the microfabrication processes, including detailed descriptions and recipes for steps such as deposition, lithography, etch, cladding, and etch facet, and then describe the measurement of the Q factor and methods to improve it. We also discuss how to extract the basic loss limit and determine the contribution of each loss source in the waveguide and resonator. We present a modified model for calculating scattering losses, which successfully relates the measured roughness of the waveguide interface to the overall performance of the device. We conclude with a summary of work done to date with low pressure chemical vapor deposition Si3N4 resonator devices, confinement, cross-sectional dimensions, bend radius, Q factor, and propagation loss.
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•Na and Li are more effective dopants to REOs in OCM than Ca and Mg but require higher temperatures.•The number of weak basic sites correlates with OCM activity for undoped REOs ...supported on MgO.•Na-doped TbOx/n-MgO more stable than Li-TbOx/n-MgO over 30h.•Highest C2H4 yield is obtained over a Li-doped CeO2/n-MgO catalyst.
The oxidative coupling of methane (OCM) to ethane and ethylene was studied over alkali metal (Li and Na) and alkaline earth metal (Mg and Ca) doped rare earth oxides (Sm2O3, TbOx, PrOy and CeO2) catalysts supported on nanoparticle magnesium oxide (n-MgO). It was found that the Li-TbOx/n-MgO catalyst outperformed all other combinations of rare earth oxide and dopant, in terms of initial activity and selectivity, except at temperatures below 600°C where the undoped Sm2O3/n-MgO, Ca-Sm2O3/n-MgO and Ca-CeO2/n-MgO catalysts resulted in higher C2+ yields. Li doping was most efficient in yielding C2+ products over all rare earth oxides, followed by doping with Na. These dopants result in the most basic sites on the surface according to CO2 desorption experiments. However, these sites are blocked at lower reaction temperatures, which can explain why most Li- and Na-doped catalysts are not active below 650°C. Below reaction temperatures of 650°C moderately basic sites, which bind CO2 up to ∼350°C, are important and correlate well with OCM activity. Li doping also resulted in the highest ethylene yields, which is a more desirable product than ethane, and the highest ethylene yield (9.7%) was obtained over the Li-CeO2/n-MgO (at 800°C). However, Li-doped catalysts are not very stable, and the Na-TbOx/n-MgO catalyst therefore outperformed the Li-TbOx/n-MgO catalyst after only a few hours on stream. Removal of both Li and Na during reaction was also confirmed and is probably the reason for the loss in selectivity with time on stream. Tb2O3 is the only TbOx phase observed with XRD on the Na- and Li-doped TbOx/n-MgO catalysts after reaction and this is important since Tb2O3 is likely more selective to C2+ products than TbO1.81 in the OCM reaction.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
Energy transferred via thermal radiation between two surfaces separated by nanometer distances can be much larger than the blackbody limit. However, realizing a scalable platform that utilizes this ...near-field energy exchange mechanism to generate electricity remains a challenge. Here, we present a fully integrated, reconfigurable and scalable platform operating in the near-field regime that performs controlled heat extraction and energy recycling. Our platform relies on an integrated nano-electromechanical system that enables precise positioning of a thermal emitter within nanometer distances from a room-temperature germanium photodetector to form a thermo-photovoltaic cell. We demonstrate over an order of magnitude enhancement of power generation (P
~ 1.25 μWcm
) in our thermo-photovoltaic cell by actively tuning the gap between a hot-emitter (T
~ 880 K) and the cold photodetector (T
~ 300 K) from ~ 500 nm down to ~ 100 nm. Our nano-electromechanical system consumes negligible tuning power (P
/P
~ 10
) and relies on scalable silicon-based process technologies.
Purpose The primary purposes of eligibility criteria are to protect the safety of trial participants and define the trial population. Excessive or overly restrictive eligibility criteria can slow ...trial accrual, jeopardize the generalizability of results, and limit understanding of the intervention's benefit-risk profile. Methods ASCO, Friends of Cancer Research, and the US Food and Drug Administration examined specific eligibility criteria (ie, brain metastases, minimum age, HIV infection, and organ dysfunction and prior and concurrent malignancies) to determine whether to modify definitions to extend trials to a broader population. Working groups developed consensus recommendations based on review of evidence, consideration of the patient population, and consultation with the research community. Results Patients with treated or clinically stable brain metastases should be routinely included in trials and only excluded if there is compelling rationale. In initial dose-finding trials, pediatric-specific cohorts should be included based on strong scientific rationale for benefit. Later phase trials in diseases that span adult and pediatric populations should include patients older than age 12 years. HIV-infected patients who are healthy and have low risk of AIDS-related outcomes should be included absent specific rationale for exclusion. Renal function criteria should enable liberal creatinine clearance, unless the investigational agent involves renal excretion. Patients with prior or concurrent malignancies should be included, especially when the risk of the malignancy interfering with either safety or efficacy endpoints is very low. Conclusion To maximize generalizability of results, trial enrollment criteria should strive for inclusiveness. Rationale for excluding patients should be clearly articulated and reflect expected toxicities associated with the therapy under investigation.
This study examined associations between Sport Concussion Assessment Tool-5 (SCAT-5) symptom reporting and gold-standard measures of anxiety and depression, and explored the utility SCAT-5 symptom ...subscales to identify anxiety and depression symptomology.
Prospective cross-sectional study.
York University in Toronto, Canada.
Preseason data were collected for varsity athletes (N = 296) aged between 17 and 25 years ( M = 20.01 years, SD = 1.69 years; 52% male).
The SCAT-5 symptom evaluation scale was used to assess baseline symptoms. The Generalized Anxiety Disorder Index-7 (GAD-7) and Patient Health Questionnaire-9 (PHQ-9) were used to assess symptoms of anxiety and depression, respectively.
Endorsement of SCAT-5 symptoms of feeling anxious, sadness, irritability, and feeling more emotional had the strongest correlations with the GAD-7 ( r' s > 0.400; P' s < 0.001). Sadness, trouble falling asleep, concentration problems, feeling slowed down, anxious, irritability, mental fog, fatigue, and memory problems had the highest correlations with the PHQ-9 ( r' s >0 .400; P' s < 0.001). The Emotional subscale from the SCAT-5 predicted mild to severe anxiety on the GAD-7 ( P < 0.001). The Sleep, Cognitive, and Emotional subscales predicted mild to severe depression on the PHQ-9 ( P' s < 0.05).
These findings provide better delineation of symptoms endorsed on the SCAT-5 symptoms that aid in identification of athletes with symptoms of anxiety or depression who may be at risk for developing a clinical disorder or experiencing persistent symptoms after a concussion.
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