Development of a 3 MV coaxial peaking capacitor for large-scale electromagnetic pulse simulator.

Coaxial peaking capacitor is a key component in high-altitude electromagnetic pulse (EMP) simulators with fast front pulse output. It poses significant technical and engineering challenges in limiting radiation field amplitude and test space. This paper presents the design and testing of a 180 pF, 3 MV coaxial peaking capacitor with improved insulation performance. In the insulation design, the length of the dielectric film is extended to reduce the background electric field on the flashover path. The electric field threshold obtained from image diagnosis is used as a reference. During capacitor testing, the insulation characteristics are diagnosed using both direct and indirect methods. The voltage measured by a D-dot probe, the output waveform of the Marx generator in the primary source, and the radiation field waveform are analyzed to understand the flashover characteristics of the capacitor and to improve the reliability of the test results. The experimental results demonstrate that the peaking capacitor can operate stably at 3.0 MV. If flashover occurring on the dropping edge of the pulse is permitted, the operating voltage can be greater than 3.7 MV without significantly affecting the radiation field waveform. The analysis on the surface flashover morphology of the peaking capacitor reveals that the flashover mainly occurs at the dropping edge of the capacitor's waveform, indicating that the damage to the film is not serious. This research significantly increases the working voltage of coaxial peaking capacitors and contributes to the development of high-altitude EMP simulation technology.

[Epidemiological Characteristics and Drug Resistance of Microbial Pathogens of Patients With Silicosis Combined With Pulmonary Infection].

Objective: To investigate the epidemiological characteristics of patients with silicosis combined with pulmonary infection in recent years, to study the distribution and the drug susceptibility of fungal and bacterial pathogens in their sputum samples, and to provide references for the prevention and treatment of silicosis and the appropriate drug use. Methods: The clinical data and drug sensitivity test results of patients with silicosis combined with pulmonary infection diagnosed at the Department of Occupational Diseases, West China Fourth Hospital, Sichuan University were retrospectively analyzed. Results: A total of 318 patients with silicosis combined with pulmonary infection who received treatment between January 2017 and December 2020 were enrolled. All the patients had positive microorganism test results. All participants were male. Their median age at the time of onset was 51.00 years and the median time of exposure to silica dust at work was 12.40 years. They worked mostly in construction, non-ferrous metal mining, and coal mining. The main types of work they did were pneumatic drilling, coal digging, and mining. The positive detection rates for the first, second and third phases of silicosis were 27.54%, 28.32%, and 32.97%, respectively. A total of 341 strains of fungal and bacterial pathogens were isolated, of which, 54.1% were fungi, including 114 strains (35.8%) of Candida albicans, and 53.1% were bacteria, including 168 strains (52.8%) of gram-negative bacteria, most of which being Klebsiella pneumoniae (30.2%). There was only 1 strain (0.3%) of gram-positive bacteria, namely Staphylococcus hemolyticus. Gram-negative bacilli were most resistant to ampicillin and highly sensitive to penicillin G and ofloxacin. Conclusion: Among patients with silicosis combined with pulmonary infection, the incidence of pulmonary infection increases along with the progress of silicosis. Microorganism analysis reveals high detection rates for fungi and the bacteria detected are predominantly gram-negative bacteria. The overall prospect for drug resistance rate was not optimistic.

Reciprocal effect between non-suicidal self-injury and depressive symptoms in adolescence.

Background: Non-suicidal self-injury (NSSI) is a common psychological and behavioral problem among adolescents. The COVID-19 pandemic has had a significant impact on people's mental health. To date, few studies have documented the temporal changes in adolescents' psychological status during the pandemic, as well as the impact of large-scale public health intervention strategies. This study contributes to the existing evidence on the subject. Methods: Participants were 6,023 adolescents aged 10 years and older, with data from two waves of longitudinal surveys, including data for a 7-month interval before and during the pandemic. A cross-lagged model was used to test the bidirectional relationship between NSSI and depressive symptoms in adolescents; logistic regression analysis was used to explore the predictors of NSSI implementation in adolescents with depressive symptoms. Results: In this study, 32.69% participants reported depressive symptoms at baseline and 34.27% at follow-up; 44.34% participants with depressive symptoms reported NSSI at baseline and 53.44% at follow-up. The duration of the online class, depressed affect, and somatic and related activity were the risk factors for NSSI; sleep duration and positive mood were the protective factors. The lag effect of depression symptoms on NSSI is significant, and so is NSSI on depressive symptoms. Conclusion: During the COVID-19 pandemic, adolescents' mental health has worsened, resulting in an increase in the prevalence of NSSI among those with depressive symptoms compared to pre-pandemic levels. Early screening for depression is crucial in preventing or decreasing NSSI in adolescents.

[Management of chronic kidney disease guided by the theory of Traditional Chinese Medicine: an experimental study].

OBJECTIVE: To determine the impact of Traditional Chinese Medicine on patients with chronic kidney disease (CKD). METHODS: A total of 225 CKD patients in an outpatient department were recruited for this study, among whom 170 received regular Western and Chinese medicine treatments (control group) and 55 received treatments guided by the theory of Traditional Chinese Medicine (experimental group). The effectiveness of the treatments was determined through a pre-post comparison. RESULTS: Significant pre-intervention differences in age (P < 0.01), stage of glomerular filtration rate (GFR) (P = 0.007) and urine protein (P < 0.01) were found between the two groups of patients. But age, gender and proteinuria were not significant predictors on clinical outcomes of the patients in the multivariate regression models. The experimental group had a greater level of decrease in blood urea nitrogen (P < 0.01) and serum creatine (P < 0. 01) than the control group. No significant differences between the groups were found in changes of uric acid (P = 0.475), urine protein (P = 0.058), urine red cells (P = 0.577), and urine white cells (P = 0.01). A greater level of increase in estimated glomerular filtration rate was found in the experimental group compared with the control (P < 0.001). The multivariate linear regression analysis identified group (B = 0.395, P < 0.001) and stage of GFR (B = 0.165, P = 0.008) as significant predictors on the outcomes of treatment. CONCLUSION: The treatment of CKD patients guided by the theory of Traditional Chinese Medicine can improve renal function through influencing glomerular filtration rate. The effect is more prominent than the regular treatment regime.

[Leukemia inhibitory factor suppresses renal interstitial fibroblast activation induced by transforming growth factor].

OBJECTIVE: To investigate the effects of leukemia inhibitory factor (LIF) on renal interstitial fibroblast activation following induction by transforming growth factor beta 1 (TGF-beta1). METHODS: Normal rat interstitial fibroblast cells (NRK/49F) were treated with TGF-beta1 and TGF-beta1, combining with LIF respectively for different duration with different concentration. Changes in cell morphology and expression of alpha-SMA were evaluated with electronic microscope and Western blot respectively. The collagen I in the supernatant was detected with ABC-ELISA. RESULTS: TGF-beta1 induced renal interstitial fibroblast activation, and this was accompanied by significant morphological transformations and secretion of collagen I. Co-culturing of cells with LIF blocked the morphological transformation. In addition, LIF inhibited TGF-beta1-induced expression of alpha-SMA mRNA and protein (P < 0.01), and decreased the levels of collagen I (P < 0.01) in a dose-dependent manner. CONCLUSION: LIF suppresses TGF-beta1-induced activation and collagen I secretion of cultured renal interstitial fibroblasts.

Immunoglobulin A1 protease: a new therapeutic candidate for immunoglobulin A nephropathy.

Immunoglobulin A nephropathy (IgAN), characterized by predominant or exclusive deposition of IgA1 in glomerular mesangium, is the most common primary glomerulonephritis worldwide. At present, the treatment is always limited due to the incomplete understanding of the pathogenesis of IgAN. Mesangial deposited IgA1 is the common final pathway leading to glomerulonephritis and renal injury. IgA1 protease, a proteolytic enzyme with strict substrate specificity for human IgA1, may be an effective therapeutic candidate for IgAN by removing the mesangial deposited IgA1.

The role of C1GALT1C1 in lipopolysaccharide-induced IgA1 aberrant O-glycosylation in IgA nephropathy.

PURPOSE: IgA1 aberrant O-glycosylation is one of the main pathogenetic features of IgA nephropathy (IgAN). This study attempted to determine the role of C1GALT1C1 in aberrant IgA1 O-glycosylation induced by lipopolysaccharide (LPS) and identify potential therapeutic targets in IgAN. METHODS: Lymphocytes isolated from 22 patients with IgAN and 17 normal controls were cultured for 3 to 7 days with or without LPS and 5-azacytidine (5-AZA). Expression levels of C1GALT1C1 mRNA and protein were measured by real-time PCR and Western blot analysis, respectively. Concentration of IgA1 and level of O-glycosylation were determined by ELISA and Vicia villosa (VV) lectin-binding assay. Correlation analysis was performed between the expression of C1GALT1C1 protein and IgA1 O-glycosylation. RESULTS: Lymphocytes from patients with IgAN secreted more IgA1 than that from normal controls after LPS stimulation (P=0.26, 0.002 and 0.005 on the 3rd, 5th and 7th day, respectively) which could be inhibited by 5-AZA (P=0.001, 0.025 and 0.001 on the 3rd, 5th and 7th day, respectively). Moreover, LPS stimulation could obviously inhibit C1GALT1C1 expression in patients with IgAN (decreased by 71%, 82% and 92% on the 3rd, 5th and 7th day, respectively; P < 0.001), and cause a significant decrease of IgA1 O-glycosylation compared with normal controls (P=0.004, 0.003 and 0.03 on the 3rd, 5th and 7th day, respectively). When 5-AZA was added, the level of C1GALT1C1 expression increased dramatically (1.98, 5.53 and 8.97 times on the 3rd, 5th and 7th day, respectively; P < 0.001) along with an increase of IgA1 O-glycosylation (P=0.295, 0.09 and 0.003 on the 3rd, 5th and 7th day, respectively). However, normal controls showed no significant change in C1GALT1C1 expression and IgA1 O-glycosylation after LPS stimulation (P > 0.05). CONCLUSION: LPS induced IgA1 aberrant O-glycosylation and suppressed C1GALT1C1 expression in patients with IgAN. Upregulation of C1GALT1C1 expression by 5-AZA could reverse the IgA1 aberrant O-glycosylation. These results suggest that C1GALT1C1 may play a key role in the regulation of IgA1 O-glycosylation.