Testing and Optimizing a Stove-Powered Thermoelectric Generator with Fan Cooling

In order to provide heat and electricity under emergency conditions in off-grid areas, a stove-powered thermoelectric generator (STEG) was designed and optimized. No battery was incorporated, ensuring it would work anytime, anywhere, as long as combustible materials were provided. The startup performance, power load feature and thermoelectric (TE) efficiency were investigated in detail. Furthermore, the heat-conducting plate thickness, cooling fan selection, heat sink dimension and TE module configuration were optimized. The heat flow method was employed to determine the TE efficiency, which was compared to the predicted data. Results showed that the STEG can supply clean-and-warm air (625 W) and electricity (8.25 W at 5 V) continuously at a temperature difference of 148 °C, and the corresponding TE efficiency was measured to be 2.31%. Optimization showed that the choice of heat-conducting plate thickness, heat sink dimensions and cooling fan were inter-dependent, and the TE module configuration affected both the startup process and the power output

Compact Water-Cooled Thermoelectric Generator (TEG) Based on a Portable Gas Stove

A compact water-cooled thermoelectric generator (TEG) based on a portable gas stove was designed and analyzed to supply electricity in off-grid scenarios. The TEG incorporates a newly designed heat collector, eight thermoelectric (TE) modules, and a radiator to ensure its portability (5.9 kg) and sufficiency of electric power (12.9 W). Detailed measurements and discussions on power load feature and TE efficiency are presented. Experiments showed that the power generation capability of the proposed TEG is compromised by its compactness over previous water-cooled TEGs. A theoretical model incorporated with heat leaks from various origins has been developed to illustrate that the designed TEG exerts the potential of every TE module, and to reveal the proportion of various heat fluxes. The predicted electric power, various heat fluxes, and TE efficiency agree well with experimental data. The limitations of TE efficiency and the nonlinearity caused by Joule heat are discussed quantitatively

Plasma levels of alarmin HNPs 1–3 associate with lung dysfunction after cardiac surgery in children

Abstract Background Early onset of lung injury is considerable common after cardiac surgery and is associated with increasing in morbidity and mortality, but current clinical predictors for the occurrence of this complication always have limited positive warning value. This study aimed to evaluate whether elevated plasma levels of human neutrophil peptides (HNPs) 1–3 herald impaired lung function in infants and young children after cardiac surgery necessitating cardiopulmonary bypass (CPB). Methods Consecutive children younger than 3 years old who underwent cardiac surgery were prospectively enrolled. Plasma concentrations of HNPs 1–3 and inflammatory cytokines were measured before, and immediately after CPB, as well as at 1 h, 12 h, and 24 h after CPB. Results Thirty patients were enrolled, 18 (60%) of whom were infants. Plasma levels of HNPs 1–3 and the pro-inflammatory cytokine interleukin-6 (IL-6) significantly increased immediately after CPB (P < 0.001), while IL-8 increased 1 h after the CPB operation (P = 0.002). The anti-inflammatory cytokine IL-10 levels were also significantly elevated immediately after CPB compared with the baseline (P < 0.001). The stepwise multiple linear regression analysis showed that the plasma HNPs 1–3 levels immediately after CPB was independent correlated with the declined lung function, as reflected by the PaO2/FiO2 ratio on the first 2 days after operation (for the first day: OR, −1.067, 95% CI, −0.548 to −1.574; P < 0.001; for the second day: OR, −0.667, 95% CI, −0.183 to −1.148; P = 0.009) and prolonged mechanical ventilation time (OR, 0.039, 95% CI, 0.005 to 0.056; P = 0.011). Plasma levels of HNPs 1–3 and IL-10 returned to the baseline values, while IL-6 and IL-8 levels remained significantly higher than baseline 24 h after CPB (P ≤ 0.01). Conclusions Elevated HNPs 1–3 levels immediately after CPB correlate with impaired lung function, and HNPs 1–3 could serve as a quantifiable early alarmin biomarker for onset of lung injury in infants and young children undergoing cardiac surgery with CPB

Potential Role of microRNA-21 in the Diagnosis of Gastric Cancer: A Meta-Analysis

<div><p>Introduction</p><p>Accumulating evidences indicate that microRNA-21(miR-21) show significant high concentration in plasma of gastric cancer (GC) patients compared to normal individuals, suggesting that it may be a useful novel diagnostic biomarker for gastric cancer. Therefore, we aimed to assess the potential diagnostic value of miR-21 for gastric cancer in this study.</p><p>Methods</p><p>Literature database including PubMed, Embase, the Cochrane Library, Web of Science, Ovid, SciVerse, Science Direct, Scopus, BioMed Central, Biosis previews,Chinese Biomedical Literature Database (CBM), Chinese National Knowledge Infrastructure (CNKI), Technology of Chongqing (VIP), and Wan Fang DATA were searched for publications concerning the diagnostic value of miR-21 for GC without language restriction. The quality of each study was scored with the Quality Assessment of Diagnostic Accuracy Studies (QUADAS). Then, data were retrieved from any qualified article hits and subject to meta-analysis. Receiver operating characteristic curves (ROC) were used to check the overall test performance. Evidence of heterogeneity was evaluated using the Chi-square and <i>I</i>² test.</p><p>Results</p><p>Five studies with a total 251 GC patients and 184 control individuals were included in this meta-analysis. All of the included studies are of high quality (QUADAS score$13). The summary estimates revealed that the pooled sensitivity is 66.5% (95% confidence interval (CI): 55.0%–76.3%) and the specificity is 83.1% (95% CI: 69.4%–91.5%). In addition, the area under the summary ROC curve (AUC) is 0.80.</p><p>Conclusion</p><p>The current evidence suggests that miR-21 has potential diagnostic value with a moderate sensitivity and specificity for GC. More prospective studies on the diagnostic value of miR-21 for GC are needed in the future.</p></div

Summary of studies using miR-21 as a biomarker of GC and study quality assessment.

<p>Note: *Calculated from independent patient data (IPD) QUADAS = quality assessment for studies of diagnostic accuracy. AUC = Area under the curve of a receiver operator curve. NR = not report. Se = sensitivity. Sp = specificity.</p

Forest plots of sensitivities and specificities from test accuracy studies of miR-21 in the diagnosis of GC.

<p>Forest plots of sensitivities and specificities from test accuracy studies of miR-21 in the diagnosis of GC.</p

Funnel plot for the assessment of potential bias in miR-21 assays.

<p>Funnel plot for the assessment of potential bias in miR-21 assays.</p

Le Courrier

06 juin 18221822/06/06 (A0,N157)