Simulation-Based Analysis of the Effect of Alpha Irradiation on GaN Particle Detectors.

Radiation-hardened semiconductor GaN has drawn considerable attention owing to its excellent properties such as large displacement energy. Many studies have focused on evaluating the degradation of GaN-based power device performance by proton beam or particle irradiation, while quantitative analysis of the energy transfer process of particles inside the material and the mechanisms involved in inducing degradation of electrical properties are rare. Here, on the basis of the fabricated alpha-particle detector, a device model validated by basic electrical experiments is established to simulate the influence of alpha-particle irradiation on the leakage current of the device. We observe that the current does not change significantly with increasing radiation fluence at low bias, while it shows a descending trend with increasing radiation fluence at higher bias. However, increasing the energy of the radiation particles at the same radiation fluence directly leads to a monotonically elevated leakage current. Such a series of phenomena is associated with radiation-induced changes in the density of trapped states within the active layers of the device.

An Analytical Model of Dynamic Power Losses in eGaN HEMT Power Devices.

In this work, we present an analytical model of dynamic power losses for enhancement-mode AlGaN/GaN high-electron-mobility transistor power devices (eGaN HEMTs). To build this new model, the dynamic on-resistance (Rdson) is first accurately extracted via our extraction circuit based on a double-diode isolation (DDI) method using a high operating frequency of up to 1 MHz and a large drain voltage of up to 600 V; thus, the unique problem of an increase in the dynamic Rdson is presented. Then, the impact of the current operation mode on the on/off transition time is evaluated via a dual-pulse-current-mode test (DPCT), including a discontinuous conduction mode (DCM) and a continuous conduction mode (CCM); thus, the transition time is revised for different current modes. Afterward, the discrepancy between the drain current and the real channel current is qualitative investigated using an external shunt capacitance (ESC) method; thus, the losses due to device parasitic capacitance are also taken into account. After these improvements, the dynamic model will be more compatible for eGaN HEMTs. Finally, the dynamic power losses calculated via this model are found to be in good agreement with the experimental results. Based on this model, we propose a superior solution with a quasi-resonant mode (QRM) to achieve lossless switching and accelerated switching speeds.

LncRNA CASC11 upregulation promotes HDAC4 to alleviate oxidized low-density lipoprotein-induced injury of cardiac microvascular endothelial cells.

Long noncoding RNAs (LncRNAs) are essential to regulate the pathogenesis of coronary artery disease (CAD). This study was conducted to analyze the functionality of long noncoding RNA cancer susceptibility candidate 11 (lncRNA CASC11) in oxidized low-density lipoprotein (ox-LDL)-induced injury of cardiac microvascular endothelial cells (CMECs). CMECs were treated with ox-LDL to induce the CAD cell model. The cellular expression levels of CASC11 and histone deacetylase 4 (HDAC4) were determined by real-time quantitative polymerase chain reaction or Western blot assay. Cell absorbance, apoptosis, angiogenesis, and inflammation were evaluated by cell counting kit-8, flow cytometry, tube formation, and enzyme-linked immunosorbent assays. The subcellular localization of CASC11 was examined by the nuclear/cytoplasmic fractionation assay. The binding of human antigen R (HuR) to CASC11 and HDAC4 was analyzed by RNA immunoprecipitation. HDAC4 stability was determined after actinomycin D treatment. CASC11 was found to be decreased in the CAD cell model. CASC11 upregulation increased cell viability and angiogenesis and reduced apoptosis and inflammation. CASC11 bound to HuR and improved HDAC4 expression. HDAC4 downregulation counteracted the protective role of CASC11 overexpression in CMECs. In summary, CASC11 alleviated ox-LDL-induced injury of CMECs by binding to HuR and stabilizing HDAC4.

Evaluation on Temperature-Dependent Transient VT Instability in p-GaN Gate HEMTs under Negative Gate Stress by Fast Sweeping Characterization.

In this work, temperature-dependent transient threshold voltage (VT) instability behaviors in p-GaN/AlGaN/GaN HEMTs, with both Schottky gate (SG) and Ohmic gate (OG), were investigated systematically, under negative gate bias stress, by a fast voltage sweeping method. For SG devices, a concave-shaped VT evolution gradually occurs with the increase in temperature, and the concave peak appears faster with increasing reverse bias stress, followed by a corresponding convex-shaped VT recovery process. In contrast, the concave-shaped VT evolution for OG devices that occurred at room temperature gradually disappears in the opposite shifting direction with the increasing temperature, but the corresponding convex-shaped VT recovery process is not observed, substituted, instead, with a quick and monotonic recovery process to the initial state. To explain these interesting and different phenomena, we proposed physical mechanisms of time and temperature-dependent hole trapping, releasing, and transport, in terms of the discrepancies in barrier height and space charge region, at the metal/p-GaN junction between SG and OG HEMTs.

Diagnostic efficacy of sentinel lymph node in breast cancer under percutaneous contrast-enhanced ultrasound: An updated meta-analysis.

BACKGROUND: To investigate the diagnostic efficacy of sentinel lymph nodes (SLN) in breast cancer by percutaneous contrast-enhanced ultrasound (CEUS) through pooled analysis of relevant studies published before June 2021. METHODS: We conducted a systematic review and meta-analysis of relevant studies by searching the electronic databases of PubMed, Embase, Cochrane Library, Chinese National Knowledge Infrastructure, Wanfang and VIP and the studies were screened according to their inclusion and exclusion criteria. Sensitivity (SEN), specificity (SPE), positive likelihood ratio (+LR), negative likelihood ratio (-LR) and diagnostic odds ratio (DOR) were calculated by Meta-disc 1.4 software and the summary receiver operating characteristic (SROC) curve and area under the curve of ROC (AUC) were constructed. RESULTS: Twenty-two publications evaluating the diagnostic efficacy of SLN in breast cancer under percutaneous CEUS were included in the meta-analysis. The diagnostic sensitivity, specificity were 0.86 (95% CI: 0.83-0.88) and 0.89 (95% CI: 0.87-0.91) for SLN in breast cancer detected by percutaneous CEUS respectively using a random effect model. The +LR and -LR were combined in a random effect model due to significant statistical heterogeneity (p < 0.05). The pooled +LR, -LR were 7.06 (95% CI: 4.34-11.50), and 0.17 (95% CI: 0.12-0.24), respectively. The combined DOR was 53.32 (95% CI: 29.74-95.61) for SLN diagnosis in breast cancer by percutaneous CEUS under a random effect model. The AUC was 0.94 which indicated that CEUS had high diagnostic efficacy of SLN in patients with breast cancer. CONCLUSIONS: CEUS is a noninvasive method for the detection SLN in patients of breast cancer with relative high prediction efficacy.

Correlation of Ultrasound Synovitis Joint Count with Disease Activity and Its Longitudinal Variation with Treatment Response to Etanercept in Rheumatoid Arthritis.

More research is needed into rheumatoid arthritis (RA), and ultrasound (US) synovitis is a promising factor for assisting in the management of RA; however, related research is extremely limited. The goal of this study was to evaluate the correlation of US synovitis joint count with clinical features, and its longitudinal changes with treatment response to etanercept in RA. We consecutively enrolled 117 people with active RA being treated with etanercept. US synovitis joint count was evaluated in 28 joints at baseline (W0), week 4 (W4), week 12 (W12) and week 24 (W24) after initiation of etanercept treatment. The mean (±standard deviation), median, inter-quartile range, and total range of the US synovitis joint count at W0 were 9.3 ± 4.0, 9.0, 7.0-11.0 and 2.0-21.0, respectively. US synovitis joint count was positively associated with tenderness joint count, swollen joint count, erythrocyte sedimentation rate, 28-joint Disease Activity Score based on erythrocyte sedimentation rate and Health Assessment Questionnaire-Disability Index score. Then participants were categorized into response and non-response groups according to their response status at W24. Further analyses showed that US synovitis joint count gradually decreased from W0 to W24, and displayed a more notable declining trend in the response group compared with the non-response group. In addition, US synovitis joint count at W0 and W4 was similar between groups, but at W12 and W24 it was markedly decreased in the response group compared with the non-response group. In conclusion, US synovitis joint count correlates with disease activity, and its longitudinal decrease is associated with treatment response to etanercept in RA.

Metal oxide semiconductor nanomembrane-based soft unnoticeable multifunctional electronics for wearable human-machine interfaces.

Wearable human-machine interfaces (HMIs) are an important class of devices that enable human and machine interaction and teaming. Recent advances in electronics, materials, and mechanical designs have offered avenues toward wearable HMI devices. However, existing wearable HMI devices are uncomfortable to use and restrict the human body's motion, show slow response times, or are challenging to realize with multiple functions. Here, we report sol-gel-on-polymer-processed indium zinc oxide semiconductor nanomembrane-based ultrathin stretchable electronics with advantages of multifunctionality, simple manufacturing, imperceptible wearing, and robust interfacing. Multifunctional wearable HMI devices range from resistive random-access memory for data storage to field-effect transistors for interfacing and switching circuits, to various sensors for health and body motion sensing, and to microheaters for temperature delivery. The HMI devices can be not only seamlessly worn by humans but also implemented as prosthetic skin for robotics, which offer intelligent feedback, resulting in a closed-loop HMI system.

Performance of Monolayer Blue Phosphorene Double-Gate MOSFETs from the First Principles.

We systematically study the device characteristics of the monolayer (ML) blue phosphorene metal-oxide semiconductor field-effect transistors (MOSFETs) by using ab initio quantum-transport simulations. The ML blue phosphorene MOSFETs show superior performances with ultrashort-channel length. We first predict the ultrascaled ML blue phosphorene MOSFETs with proper doping concentration and underlap structures are compliant with the high-performance (HP) and low-power (LP) requirements of the International Technology Roadmap for Semiconductors in the next decade in the aspects of the on-state current, delay time, and power dissipation. Encouragingly, the performances of the ML blue phosphorene MOSFETs are superior to that of the MOSFETs based on arsenene, antimonene, InSe, etc. in terms of the on-state current at similar device size. We also consider the electron-phonon scattering in 10.2 nm gate ML blue phosphorene MOSFET. It is found that the on-state current with the scattering of the blue phosphorene device is degraded by 25.4 and 23.6% for HP and LP applications, which can also fulfill the HP and LP application target. Therefore, we can deduce that ML blue phosphorene is an alternative channel material to silicon for ultrascaled FETs if the large-scale and high-quality blue phosphorene can be achieved.

An ultra-sensitive and selective nitrogen dioxide sensor based on a novel P2C2 monolayer from a theoretical perspective.

The sensing properties of an α phase black phosphorus carbide (P2C2) monolayer for the adsorption of CO2, H2, H2O, N2, H2S, NH3, O2 and NO2 gases are theoretically investigated using first-principles calculations. We calculate the adsorption energy, equilibrium distance, Mulliken charge transfer, electron localization function, and work function to explore whether P2C2 is suitable for detecting NO2 gas. The results demonstrate that the P2C2 monolayer is highly sensitive and selective to NO2 gas molecules with robust adsorption energy and superior charge transfer due to the existence of strong orbital hybridization between the NO2 molecule and monolayer P2C2. In addition, the results of the work function calculations indicate that field effect transistor type NO2 gas sensors based on P2C2 monolayers are also feasible. Furthermore, the current-voltage curves reveal that the adsorption of NO2 can greatly modify the resistance of the P2C2 monolayer. Our results show that gas sensors based on P2C2 monolayers could be better than those based on black phosphorene (BP) for detecting NO2 molecules in an air mixture. In addition, the recovery time of the P2C2 sensor at T = 300 K was estimated to be short (and even shorter at higher temperatures) for NO2 which satisfies the demands for sustainable use.

Prediction value of unmeasurable MR enhancement at early stage after gross-total resection on the survival state of patients with high-grade glioma.

PROPOSE: To explore the value of unmeasurable enhancement pattern of residual cavity in predicting survival at early stage after gross-total resection in high-grade glioma (HGG) patients. METHODS: This retrospective study enrolled consecutive 51 HGG patients with unmeasurable enhancement who underwent gross-total resection followed by concurrent chemoradiotherapy and adjuvant chemotherapy. We evaluated the enhancement patterns of residual cavity on contrast-T1WI made within 1 month after tumor resection (20 ± 3 days). The survival state of different enhancement was compared. RESULTS: Thin-linear, thick-linear and nodular enhancement were observed in 22 patients (43%), 10 patients (20%), and 19 patients (37%), respectively. The progression-free survival of patients with thin-linear (487, 151-887 days) was longer than those patients with thick-linear (277, 133-573 days), and nodular enhancement (210, 120-765 days) (P = 0.002). The overall survival of patients with thin-linear (774, 457-1343 days) was longer than those with thick-linear (462, 320-678 days), and nodular enhancement (326, 234-1393 days) (P = 0.002). There was no significant difference of orthogonal value between thick-linear and nodular enhancement (0.854), neither between grade III and IV with same enhancement patterns (P = 0.540, P = 0.720). CONCLUSIONS: The unmeasurable enhancement patterns in HGG patients within 1 month after gross-total resection, which might be better than the grade of tumor, holds a potential marker in survival state.

Increasing FLAIR signal intensity in the postoperative cavity predicts progression in gross-total resected high-grade gliomas.

To evaluate the prognostic value of fluid-attenuated inversion recovery (FLAIR) signal intensity of postoperative cavity on progression free survival (PFS) and overall survival (OS) in patients with high-grade gliomas (HGG). This study retrospectively enrolled 45 consecutive HGG patients. These patients had chemoradiotherapy after gross-total resection of tumors. Quantitative analysis of the FLAIR signal intensity in postoperative cavity and background was made. We evaluated the threshold value, accuracy, sensitivity, specificity, and survival state with this technique. The patients who progressed and patients who did not progress were 33 and 12 cases separately. The ratio of postoperative cavity and background (C-B) on FLAIR sequence in patients who progressed was higher than that of patients who did not progress (P = 0.014). The PFS of the patients who progressed was shorter than that of patients who did not progress (P = 0.008). The area under ROC curve, threshold, sensitivity, specificity of C-B ratio for predicting tumor progression were 0.875, 62.3, 69.7, 0.84, and 0.50% respectively. The PFS of lower signal group was much longer than that of higher signal group (P = 0.004). The OS of the patients with higher signal was shorter than that of patients with lower signal (P = 0.034). The increase of gray value of FLAIR in postoperative cavity may be used as an imaging marker for predicting tumor progression.

Relaxin ameliorates high glucose-induced cardiomyocyte hypertrophy and apoptosis via the Notch1 pathway.

The present study aimed to investigate the role of relaxin (RLX) on high glucose (HG)-induced cardiomyocyte hypertrophy and apoptosis, as well as the possible molecular mechanism. H9c2 cells were exposed to 33 mmol/l HG with or without RLX (100 nmol/ml). Cell viability, apoptosis, oxidative stress, cell hypertrophy and the levels of Notch1, hairy and enhancer of split 1 (hes1), atrial natriuretic polypeptide (ANP), brain natriuretic peptide (BNP), manganese superoxide dismutase (MnSOD), cytochrome C and caspase-3 were assessed in cardiomyocytes. Compared with the HG group, the viability of H9c2 cells was increased by RLX in a time- and dose-dependent manner, and was accompanied with a significant reduction in apoptosis. Furthermore, RLX significantly suppressed the formation of reactive oxygen species and malondialdehyde, and enhanced the activity of SOD. In addition, the levels of ANP, BNP, cytochrome C and caspase-3 were increased and Notch1, hes1 and MnSOD were inhibited in the HG group compared with those in the normal group. However, the Notch inhibitor DAPT almost abolished the protective effects of RLX. These results suggested that RLX protected cardiomyocytes from HG-induced hypertrophy and apoptosis partly through a Notch1-dependent pathway, which may be associated with reducing oxidative stress.

A meta-analysis of contrast-enhanced ultrasound for small hepatocellular carcinoma diagnosis.

OBJECTIVE: To discuss the efficacy of contrast-enhanced ultrasound (CEUS) for diagnosis of small hepatocellular carcinoma (HCC) by pooling the open published data. METHODS: A comprehensive publication electronic search was performed by reviewers in the databases of PubMed, Embase, Web of Science, and China National Knowledge Infrastructure. The open published studies about CEUS for small HCC diagnosis were collected. The sensitivity, specificity, positive likelihood ratio (+LR), negative likelihood ratio (-LR), and diagnostic odds ratio (DOR) were pooled by stata 12.0 software. RESULTS: A total of 16 studies were included in the present study. The sensitivity, specificity, +LR, and -LR were aggregated by random effects model because of significant heterogeneity (I2 >50.0%). However, DOR was pooled by fixed effects model without significant heterogeneity (I2 <50.0%). The aggregate sensitivity was 0.86 (95% confidence interval [CI]: 0.79-0.91); the aggregate specificity was 0.87 (95% CI: 0.75-0.94); the aggregate +LR and -LR were 7.06 (95% CI: 1.64-30.36) and 0.20 (95% CI: 1.64-30.36), respectively. The DOR was 33.71 (95% CI: 20.34-55.88); the area under the receiver operating characteristic was 0.93 (95% CI: 0.90-0.95). There was significant publication bias tested by funnel plot and line regression test (t = 2.29, P < 0.05). CONCLUSION: With the present evidence, CEUS is useful for diagnosis of small HCC with relatively high sensitivity and specificity.

Quantitative assessment of physiological cerebrospinal fluid flow in the cervical spinal canal with 3.0T phase-contrast cine MRI.

A total of 50 healthy volunteers aged between 18 and 54 years underwent phase-contrast cine MRI to assess cerebrospinal fluid flow characteristics in different regions of the vertebral canal. The results revealed that the cerebrospinal fluid peak flow velocity and peak flow rate in the systolic phase were significantly greater than those in the diastolic phase at the same level in the subarachnoid space of the cervical spinal canal. The ventral peak flow velocity and peak flow rate were significantly greater than the post-lateral peak flow velocity and flow rate, while there were no differences between left and right post-lateral subarachnoid peak velocity and flow rate. Moreover, there were no significant differences in peak flow velocity and peak flow rate between the systolic and diastolic phases, ventral, right post-lateral or left post-lateral peak flow velocity and peak flow rate at the same level in the subarachnoid space of the cervical spinal canal among different age groups (18-24, 25-34, 35-44, ≥ 45 years).