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The kink effect is a phenomenon that typically occurs in InP-based InAlAs/InGaAs high electron mobility transistors (HEMTs) at cryogenic temperatures. It results in higher output conductance (gDS) and non-monotonic behavior. This Letter discusses the origin and suppression of the kink effect in InP HEMTs at cryogenic temperatures, which is linked to the structure of gate recess passivation. At room temperature, two devices with different gate recess passivation structures show similar characteristics. However, a temperature-sensitive kink is observed in the non-passivated gate recess structure, leading to the discontinuous transconductance (gm) and the non-monotonic threshold voltage (Vth) shifts. Based on pulsed and static (non-pulsed) measurement data, surface traps and impact ionization in the high-field region are identified as the origin of the kink effect. Specifically, a positive Vth shift of +160 mV is caused by surface traps when the temperature drops to 150 K. A negative Vth shift of –60 mV is due to the enhanced impact ionization below 150 K. Conversely, the device with a passivated gate recess has a negligible kink effect and effectively improves discontinuous gm and the non-monotonic Vth shifts (+25 mV) when the temperature drops. Therefore, the device with a passivated gate recess is significant for suppressing the kink effect and maintaining the stability of the device in variable temperature environments. [ABSTRACT FROM AUTHOR]

OBJECTIVES To investigate the feasibility and safety of non-robotically assisted totally thoracoscopic closure for atrial septal defect (ASD) on perfused beating hearts. METHODS Twenty-four patients (8–45 years, mean 14.4 ± 18.7) underwent ASD closure on beating hearts by a totally thoracoscopic approach without the aid of a robotic surgical system. Additional 72 patients undergoing totally thoracoscopic ASD closure on cardioplegic arrested hearts were selected as a control. Cardiopulmonary bypass (CPB) was achieved peripherally. The aorta was not cross-clamped in the study group but it was cross-clamped in the control group. RESULTS ASD closure was successful in all study and control group patients without in-hospital mortality or major complications. The total duration of operation (76 ± 9 vs. 98 ± 6 min, P = 0.012), CPB time (32 ± 5 vs. 48 ± 4 min, P = 0.001), duration of intensive care stay (10.0 ± 5.1 vs. 19.2 ± 4.2 h, P = 0.003) and post-operative hospital stay (4.5 ± 0.8 vs. 5.0 ± 1.1 days, P = 0.045) in the study group were shorter than in the control group. There was no statistically significant difference in the proportion of patients requiring in-operation blood transfusion between study group and control group (25.0 vs. 36.1%, P = 0.226). Follow-up transthoracic echocardiography on Day 5 and Day 30 showed no residual shunts in study or control group patients. CONCLUSIONS Non-robotically assisted totally thoracoscopic closures of ASD on perfused beating hearts are feasible and safe. These procedures are associated with a shorter operation time and a shorter hospital stay than in surgeries on cardioplegic arrested hearts. [ABSTRACT FROM AUTHOR]

Objective: To investigate the effects of inhibition of lncRNA PVT1 on the proliferation, apoptosis and oxidative stress of vascular endothelial cells induced by hyperglycemic. Methods: Human umbilical vein endothelial cells (HUVECs) were cultured in vitro and divided into four groups: control group (5.5 mmol/L glucose), high glucose group (30 mmol/L glucose), high glucose + siNC group (30 mmol/L glucose +siNC, negative control group), HG + siPVT1 group (30 mmol/L glucose + siPVT1, lncRNA PVT1 silencing group). The expression of PVT1 after transfection was detected by quantitative real-time PCR. MTT assay was used to detect the effect of siPVT1 (small interfering RNA PVT1) on the proliferation of HUVECs cells induced by high glucose. Flow cytometry was used to detect ROS and apoptosis of HUVECs cells induced by siPVT1. Western blot was used to detect the expression levels of apoptotic proteins such as Bax, Bcl-2, and cleaved caspase-3 in HUVECs cells. Results: Compared with the control group, after transfection with siPVT1, the expression level of PVT1 was decreased significantly ( P ＜0.05). MTT results showed that the proliferation activity of HUVECs cells in the high-glucose group was reduced significantly after 24 h and 48 h. Compared with the HG + siNC group, the proliferation activity of HUVECs cells in the HG + siPVT1 group was increased significantly ( P ＜0.05) after 24 h and 48 h. Flow cytometry results showed that ROS and apoptosis rate of HUVECs cells in the high-glucose group were increased significantly compared with the control group. Compared with the HG + siNC (negative control) group, ROS and apoptosis rates of HUVECs cells in the HG + siPVT1 group were reduced significantly. Compared with the control group, the expression levels of cleaved-caspase-3 and Bax in the high-glucose group were significantly up-regulated, while the expression level of Bcl-2 was down-regulated. Compared with the HG + siNC group, the expression levels of cleaved-caspase-3 and Bax were down-regulated, and the expression level of Bcl-2 was up-regulated. The differences were statistically significant ( P ＜0.05). Conclusion: Inhibition of lncRNA PVT1 can significantly increase the proliferation activity of HUVECs cells induced by hyperglycemia, reduce oxidative stress and inhibit cell apoptosis.

Objective: To study the immune mechanism of nourishing kidney and eliminating toxicity decoction (NKETD) on Chronic Hepatitis B (CHB), we detected the serum concentrations of IFN-γ (the characteristic cytokine of Th1), IL-17A (the characteristic cytokine of Th17) and the quantitative proportion of CD(+) 4CD(+) 25 foxp3 Treg to CD(+) 4 Treg in HBV transgenic mice., Methods: The HBV transgenic mice were randomly divided into six groups: high-dose group, middle-dose group, low-dose group, lamivudine group, model control group and normal mice control group. The serum concentrations of IFN-γ and IL-17A in mice were measured by ELISA method and the ratio of CD(+) 4CD(+) 25 foxp3 Treg to CD(+) 4 Treg was detected by Flow Cytometry Method (FCM)., Results: The decoction could increase the serum concentration of IFN-γ and decrease that of IL-17A in HBV transgenic mice. The higher the dose was, the more significantly the concentration of IFN-γ increased. And high-dose decoction could decrease the serum concentration of IL-17A in HBV transgenic mice significantly and continuously while middle-dose and low-dose decoction had no significant effects. However, there wasn't statistically significant variation on the ratio of CD(+) 4CD(+) 25 foxp3 Treg to CD(+) 4 Treg in HBV transgenic mice., Conclusion: The decoction could treat CHB by regulating the immune function by promoting the generation of Th1 and/or enhancing its function while inhibiting Th17. The immune regulation by decoction had more significant effects than lamivudine.