Enhanced Contact Performance and Thermal Tolerance of Ni/Bi2Te3 Joints for Bi2Te3-Based Thermoelectric Devices.

Ni metal has been widely used as a barrier layer in Bi2Te3-based thermoelectric devices, which establishes stable joints to link Bi2Te3-based legs and electrodes. However, the Ni/Bi2Te3 joints become very fragile when the devices were exposed to high temperature, causing severe performance deterioration and even device failure. Herein, stable Ni/Bi2Te3 joints have been established by arc spraying of the Ni barrier layer on the Bi2Te3-based alloys. The interface microstructure and contact performance including the bonding strength and contact resistivity of the arc-sprayed Ni/Bi2Te3 joints are investigated. The results indicate that, as compared with traditional Ni/Bi2Te3 joints, the arc-sprayed Ni/Bi2Te3 joints have comparably low contact resistivity while possessing a 50% higher bonding strength. Aging the joints as an exposure to high-temperature circumstances, the arc-sprayed Ni/Bi2Te3 joints exhibit much better tolerance to the thermal shock with stable bonding strength and contact resistivity. The enhanced interfacial contact performance and thermal tolerance should be attributed to the thick Ni barrier layer and interface reaction layer with good Ohmic contact. This work provides an effective strategy to establish stable joints for the Bi2Te3-based thermoelectric devices with improved thermal stability.

Cardiovascular benefits and safety of sotagliflozin in type 2 diabetes mellitus patients with heart failure or cardiovascular risk factors: a bayesian network meta-analysis.

Background: As an antidiabetic agent, sotagliflozin was recently approved for heart failure (HF). However, its cardiovascular benefits in type 2 diabetic mellitus (T2DM) patients with HF or cardiovascular (CV) risk factors have not been systematically evaluated. The aim of this study is to evaluate the cardiovascular benefits and safety of sotagliflozin in T2DM patients with HF or CV risk factors using Bayesian network meta-analysis. Methods: Data were retrieved from PubMed, Embase, Web of Science, ClinicalTrials.gov, and Cochrane Library from their inception to 16 August 2023. Randomized controlled trials (RCTs) comparing sotagliflozin with a placebo, dapagliflozin, and empagliflozin in adult T2DM patients with HF or CV risks for at least 12 weeks were included in the study. Data analysis was conducted using R 4.2.3 and Stata 17.0. Cardiovascular efficacy outcomes included HF events (hospitalization or urgent visits for HF), MACE (deaths from CV causes, hospitalizations for HF, nonfatal myocardial infarctions, and strokes), cardiovascular death, the decrease in SBP, and weight loss. Safety outcomes are urinary tract infection, diarrhea, and diabetic ketoacidosis. Results: Eleven studies with 30,952 patients were included. Compared to dapagliflozin and empagliflozin, 200 mg of sotagliflozin showed the best effect in reducing HF events [OR (95% CI), 0.79 (0.66, 0.94) and 0.90 (0.63, 1.27)]. Compared to dapagliflozin, 200 mg of sotagliflozin [OR (95% CI), 0.76 (0.66, 0.87)] was superior in preventing MACE. Compared to empagliflozin, 200 mg of sotagliflozin [OR (95% CI), 1.46 (1.04, 2.05)] was inferior in preventing CV death. Sotagliflozin showed a poorer SBP decreasing effect than empagliflozin and dapagliflozin [MD (95% CI), 1.30 (0.03, 2.56) and 2.25 (0.35, 4.14), respectively]. There was no significant difference between sotagliflozin and other interventions in weight loss. Sotagliflozin exhibited no increased risk for diabetic ketoacidosis or urinary tract infection among all interventions, however, it showed a mild risk for diarrhea than placebo [OR (95% CI), 1.47 (1.28, 1.69)]. Conclusion: Sotagliflozin displayed moderate CV benefits and acceptable safety. Sotagliflozin can be one of the recommended options for T2DM patients with HF or CV risk factors, which will be important for evidence-based use of sotagliflozin as well as decision-making of T2DM medication.

Fabrication and Excellent Performances of Bismuth Telluride-Based Thermoelectric Devices.

The barrier layer between thermoelectric (TE) legs and electrodes has crucial impact on the electrothermal conversion efficiency of the TE device; however, the interfacial reaction of the Ni metal barrier layer with TE legs in traditional Bi2Te3-based devices is harmful to the device performance. Herein, a high-quality barrier layer of a Ni-based alloy has been fabricated on both n-type and p-type Bi2Te3-based TE legs by the electroplating method. The in situ XRD results indicate that the as-prepared Bi2Te3-based TE legs with a Ni-based alloy barrier layer remain stable even at 300 °C. The high-resolution high-angle annular dark field scanning transmission electron microscopy images reveal that the Ni-based alloy barrier layer has more excellent stability than that of the Ni metal barrier layer. The Bi2Te3-based TE devices with excellent structural and performance stabilities were assembled with the as-grown high-performance n-type and p-type Bi2Te3-based leg with a Ni-based alloy barrier layer, which have lower internal resistance and higher cooling and power generation performances. A maximum cooling temperature difference over 65 K and a maximum cooling capacity of 55 W were obtained for the high-performance Bi2Te3-based TE devices. This work provides a new strategy for high-temperature applications of commercial Bi2Te3-based TE devices.