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Low-frequency (LF) noise measurements are compared for Schottky-gate AlGaN/GaN heterostructure planar and fin field-effect transistors (FinFETs) as functions of gate voltage and measuring temperature. The noise of each device type is consistent with a carrier number fluctuation model. Similar effective defect-energy Eo distributions are derived for each of the two device architectures from measurements of excess drain-voltage noise-power spectral density vs temperature from 80 to 380 K. Defect- and/or impurity-related peaks are observed in the inferred energy distributions for Eo < 0.2 eV, Eo ≈ 0.45 eV, and Eo > 0.6 eV. Significant contributions to the LF noise are inferred for nitrogen vacancies and ON and FeGa impurity complexes. Ga dangling bonds at fin interfaces with gate metal are likely candidates for enhanced noise observed in FinFETs, relative to planar devices. Reducing the concentrations of these defects and impurity complexes should reduce the LF noise and enhance the performance, reliability, and radiation tolerance of GaN-based high electron mobility transistors. [ABSTRACT FROM AUTHOR]

Current–voltage characteristics and low-frequency (LF) noise of industrial-quality AlGaAs/InGaAs/GaAs pseudomorphic high-electron-mobility transistors are evaluated as a function of bias stress and temperature. A small positive shift of threshold voltage Vth and negligible degradation in peak transconductance GM are observed under ON-state bias conditions at elevated temperatures. The Vth measurements suggest activation of an acceptor-like defect or impurity center. The GM measurements demonstrate that newly activated defects are not located close enough to the two-dimensional electron gas to scatter carriers strongly. First-principles calculations and comparisons with previous work suggest that OAs impurity centers, other oxygen-related defects, isolated AsGa antisites, and dopant-based DX centers may contribute significantly to low-frequency (LF) noise in as-processed devices. LF noise is relatively unaffected by voltage stress at elevated temperatures, consistent with the small changes in Vth and peak GM. [ABSTRACT FROM AUTHOR]

Change-point analysis of time-series data plays a vital role in various fields of earth sciences under changing environments. Most of the analysis approaches were usually designed to detect the change-point in the level of time-series mean. In this study, we aimed to propose a non-parametric approach to detect the change-point of different parameters of time-series data. In this approach, the Boot- strap method, coupling with Kernel density estimation, was first used to estimate the probability distribution function (pdf) of a parameter before and after any potential change-points. Second, the Ar-index based on the uncross area of the two pdfs was designed to quantify the difference of the parameter before and after each potential change-point. Finally, the potential change-point owning the largest Ar-index value was determined as the locations of the change-point of the parameter. The hydrological extreme series from four stations in the Hanjiang basin were used to demonstrate this approach. The Pettitt test method commonly used in hydrology was employed as a comparison to indirectly analyze the reliability of the proposed approach. The results show that change-point detected by the proposed approach in the four stations are identified with those detected by the Pettitt approach in the level of time-series mean. But in comparison with the Pettitt test, the proposed approach can provide more detection information for other parameters, such as coefficient of variation (Cv) and coefficient of skewness (Cs) of the series. The results also show that the degree of change in the series mean is greater than its Cv and Cs, while the degree of change in series Cv is greater than its Cs. [ABSTRACT FROM AUTHOR]

Objective: To evaluate the efficacy and safety of matched sibling donor allogeneic hematopoietic stem cell transplantation (allo-HSCT) for the treatment of myelofibrosis (MF). Methods: In this case series, the clinical data of 18 patients with MF who received allo-HSCT in the Department of Hematology, Peking University People's Hospital from December 2008 to December 2023 were retrospectively studied. Kaplan-Meier survival analysis and competitive risk model were used to evaluate the probabilities of 3-year overall survival (OS), disease-free survival (DFS), cumulative incidence of relapse (CIR), and transplant related mortality (TRM). The transplant related complications were also analyzed. Results: Among the 18 patients included, there were 12 males and 6 females, with a median age of 50 (range: 28-64) years. All 18 patients achieved neutrophil engraftment, and the time of neutrophil engraftment [ M ( Q 1 , Q 3 )] was 16.0 (11.8, 18.0) days. Twelve patients achieved platelet engraftment, and the platelet engraftment time was 21.0 (16.2, 43.2) days. Six patients had grade Ⅱ to Ⅳ acute graft-versus-host disease (GVHD), and six patients had chronic GVHD. The 3-year OS rate and DFS rate after transplantation were 62.2% and 52.2%, respectively. The 3-year CIR and TRM were 29.7% and 24.6%, respectively. Four patients died during follow-up, with the main cause of death being infections. Conclusion: Matched sibling allo-HSCT is a feasible option for the treatment of MF.

We introduce a discrete mathematical model for the mechanical behaviour of a planar slice of human corneal tissue, in equilibrium under the action of physiological intraocular pressure (IOP). The model considers a regular (two-dimensional) network of structural elements mimicking a discrete number of parallel collagen lamellae connected by proteoglycan-based chemical bonds (crosslinks). Since the thickness of each collagen lamella is small compared to the overall corneal thickness, we upscale the discrete force balance into a continuum system of partial differential equations and deduce the corresponding macroscopic stress tensor and strain energy function for the micro-structured corneal tissue. We demonstrate that, for physiological values of the IOP, the predictions of the discrete model converge to those of the continuum model. We use the continuum model to simulate the progression of the degenerative disease known as keratoconus, characterized by a localized bulging of the corneal shell. We assign a spatial distribution of damage (i.e. reduction of the stiffness) to the mechanical properties of the structural elements and predict the resulting macroscopic shape of the cornea, showing that a large reduction in the element stiffness results in substantial corneal thinning and a significant increase in the curvature of both the anterior and posterior surfaces., Competing Interests: We declare we have no competing interests., (© 2024 The Authors.)

Hepatosplenic candidiasis (HSC) is a rare type of candidiasis that can occur in patients with hematologic malignancies, hematopoietic stem cell transplantation. At present, there is still a lack of studies on HSC in patients with hematologic disorders. Based on The Chinese Guidelines for the Diagnosis and Treatment of Invasive Fungal Disease in Patients with Hematological Disorders and Cancers (the 6th revision), We retrospectively analyzed the clinical characteristics and prognosis of patients with HSC treated in Peking University Institute of Hematology from 2008 to 2022. Finally, eighteen patients were included, with 1 (5.6%) proven, 2 (11.1%) probable, and 15 (83.3%) possible HSC. Among them, 3 (16.7%) patients occurred after haploid hematopoietic stem cell transplantation and 15 (83.3%) patients occurred after chemotherapy. 6 (33.3%) patients had positive blood cultures, including 4 cases of Candida tropicalis and 2 cases of Candida albicans. At 4 weeks of antifungal therapy, 10 (58.8%) patients achieved partial response (PR), At 8 weeks, 1 (6.3%) patients achieved complete response and 10 (62.5%) patients achieved PR. At 6 months after diagnosis, 3 (16.7%) patients died of hematopoietic recurrence, and none of them died of HSC. As a rare fungal infection disease, HSC has a low positive rate of microbiological and histological examinations, a persistent treat cycle, and has difficulty in remission, reminding us of the need for vigilance in patients with hematopoietic disorders and persistent fever.

Human parvovirus B19 (HPVB19) belongs to Parvoviridae, a genus of erythrovirus, and has been associated with various human diseases, and HPVB19 infection is one of the most important causes of refractory anemia after allogeneic hematopoietic stem cell transplantation (allo-HSCT). This study retrospectively analyzed 24 patients with HSCT combined with HPVB19 infection to collate and summarize the clinical presentation, treatment, and regression of patients with combined HPVB19 infection after allo-HSCT and provide experience in the management of HPVB19 infection after allo-HSCT. The median age of the patients with HPVB19 infection was 25 years, and the median time of infection occurrence was +107 days after transplantation, and 22 (91.7% ) had anemia with a median hemoglobin (HGB) level of 77.5 (46-149) g/L, and 13 (54.2% ) had new-onset anemia or persistent decline in HGB. The median length of hospital stay was 19 days. Among patients with new-onset anemia or persistent decline in HGB, the mean increase in HGB after treatment with intravenous immunoglobulin and/or antiviral therapy was 15.69 g/L, and treatment was effective in 10 (76.92% ) patients. HPVB19 infection should be alerted to the development of refractory anemia after HSCT; despite the lack of specific treatment, the overall prognosis of HPVB19-infected patients is good.

Objective: To compare the efficacy of lower extremity three dimensional CT venography (CTV) and lower extremity ascending phlebography in evaluating recurrent varicose veins. Methods: A retrospective analysis was conducted on clinical data from 235 patients with unilateral recurrent varicose veins who were treated at the Department of Vascular Surgery,Beijing Shijitan Hospital,Capital Medical University, between January 2015 and December 2020.There were 112 males and 123 females, with an age of (62.5±11.4)years (range:24 to 75 years).Patients were stratified into two groups based on preoperative imaging examination:the CTV group (utilizing lower extremity venous ultrasound+lower extremity CTV) and the control group (employing lower extremity venous ultrasound+lower extremity ascending phlebography).The two groups were matched in a 1∶1 ratio using propensity score matching, resulting in 43 cases per group.Comparative analyses between the groups at the one-year postoperative follow-up were performed using independent sample t tests, Wilcoxon rank-sum tests, χ 2 tests, and linear regression analysis. Results: One year post-surgery,the CTV group exhibited a lower venous clinical severity score (VCSS) compared to the control group( M (IQR),3.0(4.3) vs. 4.0(5.8), Z =-2.038, P =0.040).Additionally, the chronic venous insufficiency patients' quality of life questionnaire (CIVIQ-20) scores were significantly higher in the CTV group than in the control group (89.0(8.0) vs. 82.5(17.0), Z =-2.627, P =0.010).Patients in the CTV group also experienced a shorter ulcer healing time compared to the control group (4.0(4.0) weeks vs. 12.0(7.0) weeks, Z =-3.217, P <0.01).Both groups showed no clinically symptomatic recurrent varicose veins or ulcers.However, they exhibited ultrasound-detectable varicose vein recurrence, with no statistically significant difference ( χ 2 =0.453, P =0.500).The number of diseased vessels requiring management based on ultrasound supplemented by CTV was 16, while the number supplemented by ascending phlebography was 7,with a statistically significant difference ( χ 2 =4.800, P =0.030).Linear regression analysis demonstrated that clinical-etiology-anatomy-pathology clinical grading and the preoperative imaging examination method exerted independent influences on VCSS and CIVIQ-20 during the one-year postoperative assessment. Conclusions: CTV-assisted ultrasound enables a direct and comprehensive evaluation and localization of diseased veins in patients with recurrent varicose veins.The utilization of lower extremity vein ultrasound combined with CTV-guided management of lower extremity vessels in minimally invasive treatment significantly improves patient prognosis, surpassing the assessment provided by ascending phlebography.

Objective: To investigate the potential of allogeneic hematopoietic stem cell transplantation (allo-HSCT) in mitigating the adverse prognosis associated with central nervous system leukemia (CNSL) and to assess the significance of prophylactic intrathecal injection. Methods: A retrospective cohort analysis was conducted involving 30 patients with acute leukemia who had a history of CNSL who underwent allo-HSCT at Peking University People's Hospital between September 2012 and March 2018 (referred to as the CNSL-positive group). In addition, 90 patients with acute leukemia were selected from the same period who underwent allo-HSCT without a history of CNSL (referred to as the CNSL-negative group) and a rigorous 1∶3 matching was performed based on disease type, disease status, and transplantation type to form the control group. The prognosis between the two groups was compared using Kaplan-Meier analysis and the high-risk factors for CNSL relapse post-transplant were identified through Cox proportional-hazards model. Results: The median age of patients in the CNSL-negative group was significantly higher than that of patients in the CNSL-positive group (32 years vs. 24 years, P =0.014). No significant differences were observed in baseline data, including sex, disease type, disease status at transplantation, donor-recipient relationship, and human leukocyte antigen consistency between the two groups. The median follow-up time was 568 days (range: 21-1 852 days). The 4-year cumulative incidence of relapse (71.4%±20.9% vs. 29.3%±11.5%, P =0.005) and the cumulative incidence of CNSL post-transplant (33.6%±9.2% vs. 1.2%±1.2%, P <0.001) were significantly higher in the CNSL-positive group than in the CNSL-negative group. Furthermore, the 4-year leukemia-free survival rate in the CNSL-positive group was significantly lower than that in the CNSL-negative group (23.1%±17.0% vs. 71.5%±11.6%, P <0.001). However, no significant differences were observed in the 4-year cumulative transplant-related mortality and overall survival rates between the two groups (both P >0.05). Multivariate analysis revealed that a history of CNSL before transplantation ( HR =25.050, 95% CI 3.072-204.300, P =0.003) was identified as high-risk factors for CNSL relapse post-transplant. Conversely, haploidentical transplantation was associated with a reduced risk of CNSL relapse post-transplant ( HR =0.260, 95% CI 0.073-0.900, P =0.034). Within the CNSL-positive group, seven patients received prophylactic intrathecal therapy after transplantation, and their CNSL relapse rate was significantly lower than that of the 23 patients who did not receive intrathecal therapy after transplantation (0/7 vs. 9/23, P =0.048). Conclusions: Patients with a history of CNSL have a higher risk of relapse and experience poorer leukemia-free survival following transplantation. The use of prophylactic intrathecal injection shows promise in mitigating CNSL relapse rates, although further validation through prospective studies is necessary to substantiate these observations.