[Child with sitosterolemia initially presenting with hemolytic anemia and thrombocytopenia: a case repore and literrature review]

This article focuses on a case study of sitosterolemia in a child who initially presented with hemolytic anemia and thrombocytopenia. Sitosterolemia is a rare autosomal recessive lipid metabolism disorder, difficult to diagnose due to its non-typical clinical manifestations. The 8-year-old patient was initially misdiagnosed with pyruvate kinase deficiency. Comprehensive biochemical and molecular biology analyses, including gene sequencing, eventually led to the correct diagnosis of sitosterolemia. This case highlights the complexity and diagnostic challenges of sitosterolemia, emphasizing the need for increased awareness and accurate diagnosis in patients presenting with similar symptoms.

[Guidelines for diagnosis and treatment of glucocorticoid-induced osteoporosis]

Glucocorticoid-induced osteoporosis (GIOP) is a skeletal disease characterized by decreased bone strength and increased fracture risk associated with long-term glucocorticoid use. GIOP is the most common secondary osteoporosis that critically affects the quality of life of patients. Currently, the incidence of GIOP in China remains high, with insufficient awareness and lack of prevention and treatment norms. Therefore, the Chinese Rheumatology Association has established this standard based on domestic and international experience, with the aim of raising awareness of prevention and treatment among clinicians, guiding the standardized diagnosis and treatment of this disease, and improving the overall prognosis of patients with GIOP.

[Expression and significance of immune checkpoint B7-homolog 4 in endometrial cancer]

Objective: To investigate the expression of B7 homolog 4 (B7-H4) and its clinical significance in endometrial cancer. Methods: A total of 833 patients with endometrial cancer admitted to Peking Union Medical College Hospital, Chinese Academy of Medical Sciences from 2009 to 2019, were enrolled. The expression of B7-H4, mismatch repair (MMR), p53, programmed cell death ligand 1 (PD-L1) protein, and CD₈⁺ T lymphocyte density in endometrial cancer tissues were detected by the EnVision two-step method of immunohistochemical staining. First-generation sequencing (Sanger method) was used to determine molecular subtyping of endometrial cancer. The χ² test was used to compare the differences in positive expression rate of B7-H4 protein in endometrial cancer tissues with different clinicopathological features and molecular subtyping, PD-L1 protein expression, and CD₈⁺ T lymphocyte density. Survival analyses [including recurrence-free survival (RFS) and disease-specific survival (DSS)] were performed for 664 patients with follow-up time≥3 months, with a median follow-up time of 31 months (range: 4-121 months), and the Cox proportional hazards regression model was used to analyze the relevant factors affecting the prognosis of patients with endometrial cancer. Results: (1) The median age of 833 patients was 58 years (range: 25-88 years); pathological type: 595 with endometrioid carcinoma, 238 with non-endometrioid carcinoma; surgical-pathological staging: 542 cases at stage Ⅰ, 38 cases at stage Ⅱ, 173 cases at stage Ⅲ, and 45 cases at stage Ⅳ. Molecular subtyping was performed in 590 patients, including 50 with POLE mutation, 163 with mismatch repair defect (MMR-d) type, 246 with nospecific molecular change (NSMP) type, and 131 with p53 mutation subtype. (2) B7-H4 protein was expressed with brownish-yellow stainind in the cell membrane and cytoplasm of endometrial carcinoma, and the positivity rate of B7-H4 protein was 71.5% (596/833). The positivity rates of B7-H4 protein among patients with different age, surgical-pathological stage, tumor grade, pathological type, depth of muscular invasion, presence or absence of lymphovascular space invasion, and molecular subtype were significantly different (all P<0.05). The positivity rates of B7-H4 protein among patients with different PD-L1 protein expression and CD₈⁺ T lymphocyte density were not significantly different (P>0.05). The 5-year RFS (83.9%) and DSS (87.3%) of B7-H4 protein-positive patients had an increasing trend compared with the 5-year RFS (77.2%) and DSS (78.1%) of B7-H4 protein-negative patients, but there were not statistically significant differences (P=0.053, P=0.083). (3) Univariate analysis showed that the 5-year RFS and DSS of patients with different age, tumor grade, surgical-pathological stage, pathological type, depth of muscular invasion, lymphovascular space invasion, and molecular subtype were significantly different (all P<0.01). There were no significant differences in 5-year RFS (P=0.184, P=0.113) and DSS (P=0.549, P=0.247) among patients with different CD₈⁺ T lymphocyte density and PD-L1 protein expression. Further analysis according to molecular subtype, the results of CD₈⁺ T lymphocyte density and PD-L1 protein expression showed that the 5-year RFS and DSS of B7-H4 protein-positive patients were higher than those of B7-H4 protein-negative patients with NSMP subtype, low density of CD₈⁺ T lymphocyte and PD-L1 protein-negative endometrial carcinoma (all P<0.05), however, there was no significant difference in 5-year DSS between B7-H4 protein-positive patients and B7-H4 protein-negative patients with PD-L1 protein-negative endometrial cancer (P=0.060). Multivariate analysis showed that positive expression of B7-H4 protein was an independent factor for 5-year RFS (HR=0.27, 95%CI: 0.09-0.78, P=0.016) and DSS (HR=0.16, 95%CI: 0.05-0.58, P=0.005) in patients with NSMP subtype endometrial carcinoma. In patients with low-density CD₈⁺ T lymphocytes endometrial cancer, positive expression of B7-H4 protein was an independent factor for 5-year RFS (HR=0.45, 95%CI: 0.26-0.80, P=0.006), but it was not an independent factor for 5-year DSS. In patients with PD-L1 protein-negative endometrial cancer, B7-H4 protein was not an independent factor for 5-year RFS. Conclusion: B7-H4 protein expressed highly in endometrial carcinoma tissues, and its high expression is closely related to clinicopathological features, molecular subtype of p53 mutant and NSMP, and the favorable prognosis of patients with low density of CD₈⁺ T lymphocyte immunophenotype endometrial carcinoma.

Constraints on Heavy Decaying Dark Matter from 570 Days of LHAASO Observations

The kilometer square array (KM2A) of the large high altitude air shower observatory (LHAASO) aims at surveying the northern γ-ray sky at energies above 10 TeV with unprecedented sensitivity. γ-ray observations have long been one of the most powerful tools for dark matter searches, as, e.g., high-energy γ rays could be produced by the decays of heavy dark matter particles. In this Letter, we present the first dark matter analysis with LHAASO-KM2A, using the first 340 days of data from 1/2-KM2A and 230 days of data from 3/4-KM2A. Several regions of interest are used to search for a signal and account for the residual cosmic-ray background after γ/hadron separation. We find no excess of dark matter signals, and thus place some of the strongest γ-ray constraints on the lifetime of heavy dark matter particles with mass between 10^{5} and 10^{9}  GeV. Our results with LHAASO are robust, and have important implications for dark matter interpretations of the diffuse astrophysical high-energy neutrino emission.

[Preliminary analysis of the promotion effect of laparoscopic standardized surgical treatment for gastric cancer in regional medical centers in Shanghai]

Objective: To explore the promotion effect of laparoscopic standardized surgery for gastric cancer observational in some regional medical centers in Shanghai. Methods: A retrospective cohort study was carried out. Eleven regional medical centers in Shanghai received the promotion program of laparoscopic standardized surgery for gastric cancer, which was led by Ruijin Hospital, Shanghai Jiaotong University School of Medicine (Shanghai Minimally Invasive Surgery Center) from January to December 2020. Clinicopathological data of gastric cancer patients treated at these 11 regional medical centers before and after the promotion program were collected. Inclusion criteria were as follows: patients undergoing laparoscopic distal gastrectomy or total gastrectomy; gastric cancer confirmed by pathology; without distant metastasis or peritoneal metastasis. Patients who did not undergo laparoscopic D2 radical resection, or received neoadjuvant chemotherapy before surgery, or without complete clinical data were excluded. Patients undergoing laparoscopic surgery from January to December 2019 were included in the pre-promotion group (46 cases). Patients undergoing laparoscopic surgery from January to December 2021 were included in the post-promotion group (102 cases). In addition, patients undergoing laparoscopic surgery at Ruijin Hospital from January 2021 to December were included in the control group (138 cases). The baseline data, perioperative measurements postoperative complications, and pathological results of the three groups were analyzed and compared. Results: There were no significant differences in baseline characteristics among the three groups (all P>0.05). Compared with the pre-promotion group, the operation time in post-promotion group was significantly shorter [(207.3±36.0) minutes vs. (254.2±47.1) minutes, t=7.038,P<0.001], and the number of harvested lymph node was significantly more (24.4±12.2 vs. 18.9±5.5, t=2.900, P=0.004). However, there were no significant differences in the extent of resection, time to fluid intake, and postoperative hospital stay between the two groups (all P>0.05). Compared with the control group, the operation time [(207.3±36.0) minutes vs (172.6±26.0) minutes, t=8.281, P<0.001], time to fluid intake [(6.3±3.2) days than (5.5±3.0) days, t=2.029, P=0.044], and the postoperative hospital stay [(14.3±5.6) days vs. (10.1±4.8) days, t=6.036, P<0.001] in the post- promotion group were still longer. Total gastrectomy was less common in the post-promotion group compared with the control group [18 cases (17.6%) vs. 41 cases (29.7%), χ²=7.380, P=0.007]. However, there was no significant difference in the number of harvested lymph node between the two groups (P>0.05). The morbidity of postoperative complication in the post-promotion group (9.8%, 10/102) was significantly lower than that in the pre-promotion group (23.9%, 11/46) (χ²=5.183, P=0.023), while above morbidity was not significantly different between the post-promotion group and the control group [9.8% vs. 6.5% (9/138), χ²=0.867, P=0.352]. Conclusion: After the promotion of laparoscopic standardized surgery for gastric cancer in regional medical centers, the standardization degree of surgery has been improved, and the morbidity of postoperative complication decreases. Laparoscopic standardized surgery for gastric cancer can be promoted to more regional medical centers.

[Relationship between simple renal cyst and adverse events in patients receiving thoracic endovascular aortic repair for Stanford B aortic dissection]

Objective: To explore the prognostic value of simple renal cyst (SRC) for adverse events in patients receiving thoracic endovascular aortic repair (TEVAR) for Stanford B aortic dissection (TBAD). Methods: This study is a retrospective cohort study. Consecutive patients receiving TEVAR for TBAD between January 2010 and December 2015 were enrolled in this study. The patients were divided into SRC group and non-SRC group. With sex and age ±2 years old as matching factors, SRC group and non-SRC group were matched by 1∶1. Collect and compare the differences of clinical data between the two groups. Adverse events were recorded through outpatient, telephone follow-up and in-hospital review. After adjusting for confounding factors, multivariate Cox regression was used to analyze the risk factors of aortic adverse events. Kaplan-Meier method was used to analyze the survival curve of SRC group and non-SRC group. Results: A total of 692 consecutive patients were recruited. Patients were divided into SRC group (n=235) and non-SRC group (n=457). After 1∶1 matching, there were 229 cases in SRC group and no SRC group respectively. The age of SRC group was (62.3±10.4) years old, 209 cases were male (91.3%), and the age of no SRC group was (62.0±10.2) years old, 209 cases were male (91.3%). Cox regression analysis showed that, after adjusting for confounding factors, comorbid SRC (HR=1.991, 95%CI: 1.090-3.673, P=0.025), TEVAR in the acute phase (HR=13.635, 95%CI: 5.969-31.147, P=0.001), general anesthesia (HR=2.012, 95%CI: 1.066-3.799, P=0.031) are independent factors of aortic-adverse events after TEVAR for TBAD. Kaplan-Meier analysis showed that the cumulative survival rate of SRC group was significantly lower than non-SRC group (log-rank P=0.031, 0.005). Conclusion: SRC is an independent predictor of aortic-related adverse events in patients following TEVAR for TBAD.

Sponge-like hierarchical porous carbon decorated by Fe atoms for high-efficiency sodium storage and diffusion

Hierarchical pores with accessible active sites in carbon are highly desired for enhancing sodium storage in sodium ion batteries (SIBs). However, it is still challenging to construct such materials with tunable architectures. Herein, a sponge-like 3D hierarchical porous Fe-doped carbon (Fe@NCS) was successfully assembled from an energetic framework. The continuous distribution of micro/meso/macro-pores in the range of 5 nm-2 μm and homogenously decorated Fe atoms were achieved, which greatly enhanced the storage and diffusion of Na⁺ ions and displayed brilliant high-rate capability and cycling stability.

Exploring Lorentz Invariance Violation from Ultrahigh-Energy γ Rays Observed by LHAASO

Recently, the LHAASO Collaboration published the detection of 12 ultrahigh-energy γ-ray sources above 100 TeV, with the highest energy photon reaching 1.4 PeV. The first detection of PeV γ rays from astrophysical sources may provide a very sensitive probe of the effect of the Lorentz invariance violation (LIV), which results in decay of high-energy γ rays in the superluminal scenario and hence a sharp cutoff of the energy spectrum. Two highest energy sources are studied in this work. No signature of the existence of the LIV is found in their energy spectra, and the lower limits on the LIV energy scale are derived. Our results show that the first-order LIV energy scale should be higher than about 10^{5} times the Planck scale M_{Pl} and that the second-order LIV scale is >10^{-3}M_{Pl}. Both limits improve by at least one order of magnitude the previous results.

[Association analysis between extracurricular physical activity and dyslipidemia among primary, middle and high school students in Guangzhou]

Objective: To investigate the prevalence of dyslipidemia, and to explore the association between extracurricular physical activity and dyslipidemia among primary, middle and high school students in Guangzhou. Methods: This cross-sectional study selected primary and middle school students in Guangzhou by the stratified cluster sampling method from March to December 2019. Physical examination and blood lipid test were performed. Information about students' basic characteristics and extracurricular physical activity was collected by questionnaire. Multivariate logistic regression analysis was used to determine the association between extracurricular physical activity and dyslipidemia in this cohort. Results: A total of 7 797 participants (mean aged (12.2±2.9) years) were included (4 194 (53.79%) boys and 3 603 (46.21%) girls]. The detection rates of high total cholesterol, high triglycerides, low high-density lipoprotein cholesterol, high low-density lipoprotein cholesterol and dyslipidemia were 12.49% (974/7 797), 6.44% (502/7 797), 6.62% (516/7 797), 11.31% (882/7 797) and 23.83% (1 858/7 797), respectively. Dyslipidemia rate was lower in the junior school students (21.39% (675/3 156)) than in primary school students (25.96% (896/3 451)) and high-school students (24.12% (287/1 190)) (P<0.001). The dyslipidemia rates of boys and girls were similar (23.15% (971/4 194) vs. 24.62% (887/3 603), P>0.05). Dyslipidemia rate was lower in students with extracurricular physical activity than in students without extracurricular physical activity (22.50% (923/4 102) vs. 25.30% (935/3 695), P<0.05). Multivariate logistic regression analysis showed that extracurricular physical activity was associated with lower risk of dyslipidemia (OR=0.88, 95%CI=0.79-0.99, P=0.033). Among all types of extracurricular physical activities, participating in extracurricular large ball game was associated with 28% lower risk among junior school students (OR=0.72, 95%CI=0.57-0.91, P=0.006). Conclusion: The prevalence of dyslipidemia is high among primary, middle and high school students in Guangzhou. Extracurricular physical activity is associated with reduced risk of dyslipidemia in this cohort.

[Preliminary clinical observation of omalizumab therapy for moderate to severe asthma]

Objective: To observe the effectiveness, safety and management of omalizumab therapy for moderate to severe asthma in real-world clinical practice in China. Methods: This retrospective analysis involved 79 patients with moderate to severe asthma who received omalizumab therapy for at least 4 months in the First Affiliated Hospital of Guangzhou Medical University from March 2018 to April 2020. All participants were between 14 to 76 years old(median 50 years),including 30 males and 49 females. Data regarding the patients' clinical manifestations, eosinophil count, fractional exhaled nitric oxide (FeNO), lung function, oral corticosteroid dosage, and adverse reactions were collected before and after treatment. Paired t-test or non-parametric paired Wilcoxon analysis was used for pairwise comparison, Mann Whitney analysis for inter-group comparison, and Chi square test or Fisher test for inter-group comparison of count data. Results: The following changes were noted after 4 months of omalizumab thearpy. The patients' Asthma Control Test (ACT) scores increased from 17.0 (13.0-19.0) to 20.0 (18.0-24.0) points (P<0.001). The frequency of acute exacerbations(AE) decreased from 1.0 (0-1.0) to 0 (0-1.0) episodes every 4 months (P<0.001). The variation rate of the peak expiratory flow (PEF) decreased from 16.5 (13.8-27.3)% to 10.4 (6.0-16.2)% (P<0.001). The percent predicted value of PEF (PEFpred%) increased from 71.7 (51.4-91.6)% to 87.5 (65.2-105.5)% (P<0.001). The percent predicted value of the forced expiratory volume in 1 second(FEV₁%pred) increased from 73.6 (53.9-90.8)% to 80.6 (68.7-91.8)% (P=0.007). The maintenance dose of oral corticosteroids (OCS) decreased from 12.0 (10.0-20.0) to 5.0 (0-17.5) mg/day (P=0.001). After 4 months of treatment, the response rate of the 79 patients with asthma was 74.7%. The response rate of patients with allergic asthma (77.3%) was higher than that of patients with non-allergic asthma (25.0%) (P=0.019). Among 5 patients who completed 1 year of treatment, the ACT score, frequency of AE, PEFpred%, variation rate of PEF and OCS maintenance dose were still improved after 1 year of treatment. Adverse reactions occurred in 3 patients (3.8%), for a total of 3 (0.6%) times. Stratified analysis showed that after 4 months of treatment, the improvement in the ACT score and the decrease in the PEF variation rate among patients who reached the recommended treatment dose (full dose) [3.0 (1.0-8.0) points, 6.5 (3.5-15.8) %] were significantly higher than those among patients who did not reach the recommended treatment dose (insufficient dose) [1.0 (-0.3-3.0) points, 2.9 (1.5-5.0) %] (P<0.05). Additionally, the treatment response rate in patients with a sufficient dose (80.0%) was higher than that in patients with an insufficient dose (50.0%) (P=0.019).The main factors associated with stopping treatment within 1 year despite a response to omalizumab was economic burden (70.3%), followed by satisfactory improvement by self-evaluation (21.9%) and less improvement in symptoms than expected (7.8%). Conclusion: Omalizumab was an effective treatment for moderate to severe allergic asthma with few adverse effects. The response rate was higher when the recommended injection dose was achieved. Financial difficulty was the main reason for stopping treatment within 1 year despite a good therapeutic response.

Peta-electron volt gamma-ray emission from the Crab Nebula

The Crab Nebula is a bright source of gamma rays powered by the Crab Pulsar's rotational energy through the formation and termination of a relativistic electron-positron wind. We report the detection of gamma rays from this source with energies from 5 × 10^-4 to 1.1 peta-electron volts with a spectrum showing gradual steepening over three energy decades. The ultrahigh-energy photons imply the presence of a peta-electron volt electron accelerator (a pevatron) in the nebula, with an acceleration rate exceeding 15% of the theoretical limit. We constrain the pevatron's size between 0.025 and 0.1 parsecs and the magnetic field to ≈110 microgauss. The production rate of peta-electron volt electrons, 2.5 × 10³⁶ ergs per second, constitutes 0.5% of the pulsar spin-down luminosity, although we cannot exclude a contribution of peta-electron volt protons to the production of the highest-energy gamma rays.

Extended Very-High-Energy Gamma-Ray Emission Surrounding PSR J0622+3749 Observed by LHAASO-KM2A

We report the discovery of an extended very-high-energy (VHE) gamma-ray source around the location of the middle-aged (207.8 kyr) pulsar PSR J0622+3749 with the Large High-Altitude Air Shower Observatory (LHAASO). The source is detected with a significance of 8.2σ for E>25  TeV assuming a Gaussian template. The best-fit location is (right ascension, declination) =(95.47°±0.11°,37.92°±0.09°), and the extension is 0.40°±0.07°. The energy spectrum can be described by a power-law spectrum with an index of -2.92±0.17_{stat}±0.02_{sys}. No clear extended multiwavelength counterpart of the LHAASO source has been found from the radio to sub-TeV bands. The LHAASO observations are consistent with the scenario that VHE electrons escaped from the pulsar, diffused in the interstellar medium, and scattered the interstellar radiation field. If interpreted as the pulsar halo scenario, the diffusion coefficient, inferred for electrons with median energies of ∼160  TeV, is consistent with those obtained from the extended halos around Geminga and Monogem and much smaller than that derived from cosmic ray secondaries. The LHAASO discovery of this source thus likely enriches the class of so-called pulsar halos and confirms that high-energy particles generally diffuse very slowly in the disturbed medium around pulsars.

Ultrahigh-energy photons up to 1.4 petaelectronvolts from 12 γ-ray Galactic sources

The extension of the cosmic-ray spectrum beyond 1 petaelectronvolt (PeV; 10¹⁵ electronvolts) indicates the existence of the so-called PeVatrons-cosmic-ray factories that accelerate particles to PeV energies. We need to locate and identify such objects to find the origin of Galactic cosmic rays¹. The principal signature of both electron and proton PeVatrons is ultrahigh-energy (exceeding 100 TeV) γ radiation. Evidence of the presence of a proton PeVatron has been found in the Galactic Centre, according to the detection of a hard-spectrum radiation extending to 0.04 PeV (ref. ²). Although γ-rays with energies slightly higher than 0.1 PeV have been reported from a few objects in the Galactic plane^3-6, unbiased identification and in-depth exploration of PeVatrons requires detection of γ-rays with energies well above 0.1 PeV. Here we report the detection of more than 530 photons at energies above 100 teraelectronvolts and up to 1.4 PeV from 12 ultrahigh-energy γ-ray sources with a statistical significance greater than seven standard deviations. Despite having several potential counterparts in their proximity, including pulsar wind nebulae, supernova remnants and star-forming regions, the PeVatrons responsible for the ultrahigh-energy γ-rays have not yet been firmly localized and identified (except for the Crab Nebula), leaving open the origin of these extreme accelerators.

[Effect of long non-coding RNA MBNL1-AS1 expression on prognosis of acute myeloid leukemia patients]

Objective: To explore the prognosis effect of the expression of long-chain non-coding RNA (lncRNA) MBNL1-AS1 on acute myeloid leukemia (AML) patients. Methods: One hundred and twenty-five AML patients of the Cancer Genome Atlas (TCGA) from November 2001 to March 2010 were involved, including 70 patients who received chemotherapy only and other 55 patients treated with allogeneic hematopoietic stem cell transplantation (allo-HSCT) in addition to chemotherapy. According to the median expression of lncRNA MBNL1-AS1, patients of chemotherapy group were divided into high expression sub-group(n=35) and low expression sub-group (n=35), and patients of allo-HSCT group were also divided into high expression sub-group (n=28) and low expression sub-group (n=27) for prognosis analysis. Clinical characteristics at diagnosis, including peripheral white blood cell counts (WBC), blast percentages in peripheral blood and bone marrow (BM), French-American-British (FAB) subtypes and the frequencies of common genetic mutations in AML were described. The event-free survival (EFS) rate and overall survival (OS) rate of patients in different groups were analyzed, and the influence of the clinical characteristics of patients on the prognosis of AML was analyzed by COX multivariate analysis. Results: In the chemotherapy group, patients with low lncRNA-MBNL1-AS1 expression had significantly lower EFS and OS (60.0%, 8.6%) than patients with high lncRNA-MBNL1-AS1 expression (68.6%, 34.3%) (χ²=7.817, 10.880, all P<0.01). However, in the alloHSCT group, no significant differences were observed in EFS and OS of patients between high and low expression groups of lncRNA-MBNL1-AS1 (all P>0.05). COX multivariate analysis confirmed that age≥60 years old (EFS: HR (95%CI): 6.934 (1.918-25.075),P=0.003;OS: HR (95%CI): 4.119 (1.812-9.364), P=0.001), and low expression of lncRNA MBNL1-AS1 (EFS: HR (95%CI): 0.354 (0.126-0.941), P=0.038; OS: HR (95%CI): 0.424 (0.231-0.778), P=0.006)were independent risk factors for EFS and OS in the chemotherapy group. Conclusion: The long-chain non-coding RNA MBNL1-AS1 is related to the prognosis of AML, and its low expression is an independent poor prognostic factor in AML patients.

[Consistency between bioelectrical impedance analysis and dual-energy X-ray absorptiometry for body composition measurement in children aged 7-17 years]

Objective: To evaluate the consistency between bioelectrical impedance analysis (BIA) and dual-energy X-ray absorptiometry (DXA) in the measurement of body composition in children and adolescents aged 7-17 years. Methods: Fat-free mass (FFM) and fat mass (FM) were measured by both BIA and DXA in 1 431 children. The consistency between the methods was evaluated by intra-class correlation coefficients (ICCs) and Bland-Altman analysis. Logarithmic transformation of both measurements was performed before Bland-Altman analysis. Results: The ICCs for FFM were 0.986 and 0.974 and ICCs for FM were 0.854 and 0.926 in boys and girls respectively. In boys, the mean ratio of FFMs by BIA and DXA was 1.04, with limits of Agreement (LoA) of 0.95-1.14, and in girls, the mean ratio of FFMs by BIA and DXA was 1.02, with the LoA of 0.90-1.15. The LoA of FFM became narrower with age in both boys and girls. Both boys and girls had the wide LoAs for FM (0.40-1.27 and 0.48-1.48, respectively). Additionally, the LoA ranges for FFM and FM narrowed with the increase of BMI level in both boys and girls. Conclusion: For all children, BIA showed good consistency with DXA for FFM, whereas significant errors occurred in FM measurement. The consistency between BIA and DXA was better for obese children than for underweight or normal-weight children.

Hybrid Zeolitic Imidazolate Frameworks for Promoting Electrocatalytic Oxygen Evolution via a Dual-Site Relay Mechanism

Developing efficient oxygen evolution reaction (OER) electrocatalysts is important for enhancing the water splitting efficiency. However, with the current catalysts containing one kind of active sites, it is challenging to achieve low overpotentials because of the four-electron transfer process. Herein is reported HZIF-2-CoMo, a new metal-organic framework with well-defined Co-Mo dual sites that can promote the OER process through an unconventional Mo⁶⁺/Co²⁺ dual-site relay mechanism. Theoretical calculations suggested that the Mo and Co sites stabilize the HO* and HOO* intermediates, respectively, and that the unique Co-O-Mo configuration induces the formation of a Co-O*-Mo transition intermediate, remarkably reducing the reaction free energy. As a result, HZIF-2-CoMo shows an overpotential of 277 mV at 10 mA cm^-2 and a low Tafel slope of 70 mV dec^-1 in alkaline solution, making it one of the best OER electrocatalysts reported to date.

Recent progress and perspectives on the structural design on metal-organic zeolite (MOZ) frameworks

As a typical group of coordination polymers, metal-organic zeolite (MOZs) frameworks inherit the topological and structural advantages of inorganic zeolites and display great application potential in many areas, including gas adsorption/separation, catalysis, luminescence and chemical sensing. In this review, we outline the recent progress in the synthesis, functionalization and application of metal-organic zeolite frameworks, mainly focusing on the basic structural design principle and synthesis strategy on 4-connect inorganic nodes and 2-connect organic linkers. Employing different valent metals, small inorganic TO₄^2- units and high-nuclear clusters as 4-connect nodes, we derived multi-types of MOZs with a modified framework charge, improved stability and enhanced photo-/eletrocatalytic activity. Besides, the selection, functionalization and defect-engineering on the 2-connect ligands generated different topological and functional MOZs. Finally, the future trends and some perspectives in this area are outlined.

Highly efficient electrocatalysts for overall water splitting: mesoporous CoS/MoS2 with hetero-interfaces

Mesoporous CoS/MoS2 with abundant heterogeneous interfaces was faciley synthesized from a bimetallic hybrid zeolitic imidazolate framework, which showed excellent catalytic activity and reaction kinetics in both the HER and OER in 1 M KOH. Meanwhile, as a cathode and anode in water splitting electrocatalysis, it delivers a low cell voltage of 1.61 V at 10 mA cm-2 and excellent durability.

CoMo-bimetallic N-doped porous carbon materials embedded with highly dispersed Pt nanoparticles as pH-universal hydrogen evolution reaction electrocatalysts

The hydrogen evolution reaction is a key half reaction for water electrolysis and is of great significance. Pt-based nanomaterials are promising candidates for HER electrocatalysts. However, the high price of platinum and poor durability impede their practical applications. Herein, a new CoMo-bimetallic hybrid zeolite imidazolate framework is employed to load Pt nanoparticles in a highly dispersed manner as a precursor to synthesize an efficient pH-universal HER electrocatalyst (PtCoMo@NC), which displays overpotentials of 26, 51, and 66 mV at a current density of 10 mA cm^-2 in acidic, basic, and neutral media, respectively. The strong synergistic effect of highly dispersed multi-type catalytic species, including cobalt, molybdenum carbide, and platinum (4.7%) promotes the catalytic activity in the HER process. Meanwhile, the aggregation of Pt nanoparticles is greatly restrained by the carbon matrix so that a brilliant long-time durability of 12 hours and a negligible current decrease in the LSV curve after 10 000 CV cycles are achieved.

Zeolitic Metal Cluster Carboxylic Framework for Selective Carbon Dioxide Chemical Fixation through the Superlarge Cage

Metal-organic frameworks (MOFs) with zeolitic structure process fantastic structural metrics and display excellent applications in many aspects; however, they are difficult to assemble. Herein, on the basis of a tetrahedral Zn₄O cluster and a 3,5-bis(2,4-dicarboxylphenyl)nitrobenzene (H₄L) ligand, a novel sodalite (SOD) zeolitic cluster framework (ZCF), {[Zn₄(O)(L)₂]·4DMF·6H₂O}_n (ZCF-1; DMF = N,N-dimethylformamide), has been hydrothermally synthesized. Compared with the traditional SOD zeolitic framework of ZIF-8, the cage size of ZCF-1 is dramatically improved from 16.9 to 29.2 Å by the introduction of longer tetradentate carboxylic ligands. Moreover, because of the functional nitryl group in the ligand, ZCF-1 exhibits a high CO₂/CH₄ selectivity. Hence, further research on the chemical fixation of CO₂ is implemented, which reveals excellent heterogeneous catalytic activity and durability. Especially, a unique selective catalytic performance with a high yield of 88.3% on a larger molecular size reactant (glycidyl phenyl ether) is observed, which is attributed to the stereoselection effect of the superlarge cage and abundant Zn₄O catalytic clusters in ZCF-1.

Effect of peak power enhancement of ferrite phase shifter from full-height to increased-height rectangular waveguide

In order to enhance the high-power performance of the ferrite phase shifter (PS), a method of increasing waveguide height is proposed and experimentally demonstrated. Dual-toroid geometry is utilized as a high-power structure. Two configurations of X-band PSs with full-height (FH) and increased-height (IH) waveguides are designed and fabricated while keeping other parameters consistent. Comparative analysis based on simulation and high-power experiments is conducted. The simulation results agree well with experiments. Compared with the FHPS, the IHPS can enhance the peak-power-capacity from 90 kW to 140 kW while maintaining almost the same insertion loss of 0.5 dB with a slight increase in differential phase shift from 360° to 380°.

P5609Outcomes of chimney technique for aortic arch diseases: a single-center experience with 226 cases

Objective

The aim of the present study is to report our single-center experience with chimney technique for aortic arch diseases and the early- and mid-term outcomes in these patients.

Methods

From August 2012 to October 2017, 226 patients (mean age 54±12 years; 197 men) with aortic arch diseases underwent thoracic endovascular aortic repair combined with chimney stents. Pathologies included type B aortic dissection (n=185), aortic arch aneurysm/descending thoracic aortic aneurysm (n=13), aortic arch pseudoaneurysm (n=10), penetrating aortic ulcer (n=7), intramural hematoma (n=7), and aortic rupture (n=4).

Results

The aortic stent-grafts were deployed in zone 0 (n=22), zone 1 (n=13), and zone 2 (n=191). A total of 230 chimney stents were deployed (innominate artery, n=21; right common carotid artery, n=1; left common carotid artery, n=13; left subclavian artery, n=195). The technical success rate was 84% (189/226) and immediate type Ia endoleak occurred in 37 (16%) patients. In the early-term, four patients died, of which from aortic rupture (n=1), ventricular fibrillation (n=1) or major stroke (n=2). Four major strokes occurred (two patients died and two recovered), but no reintervention was recorded. Spinal cord ischemia developed in three patients. The mean duration of follow-up was 22±16 months. Late type Ia endoleaks were recorded in two patients. Chimney stent occlusions were recorded in six patients. During follow-up, five patients died, of which from aortic rupture (n=3), cerebral hemorrhage (n=1) or rectal cancer (n=1). Two major strokes occurred (one patient died and one recovered) and reintervention performed in one case.

Conclusion

The chimney technique for aortic arch diseases is safe and feasible. And long-term follow-up observation is needed.

[Role and mechanism of lipopolysaccharide induced exosome in the pathogenesis of acute lung injury]

Objective: To explore the effect and mechanism of exosome derived from lipopolysaccharide (LPS)-induced mouse macrophage (RAW264.7) on acute lung injury. Methods: RAW264.7 were cultured in vitro and divided into 2 groups: control group and LPS-induced group. The exosomes were extracted from the two groups of cell supernatant by ultracentrifugation and classified into 2 groups: C-EXO group and LPS-EXO group. In vivo, random allocation was used to averagely divide the eighteen male C57BL/6 mice into 3 groups: control group, EXO-control group and EXO-LPS group. All mice were sacrificed after 12 h. The lung tissue was used for HE staining to assess the degree of acute lung injury as well as immunohistochemical staining for interleukin (IL) -1β and tumor necrosis factor (TNF)-α. The tissue protein expression levels of IL-1β, TNF-α, β-catenin, E-cadhein, ZO-1 and Occludin were measured by Western blot. In vitro, alveolar type Ⅱ epithelial cells (MLE-12) were cultured and divided into 3 groups: C-control group, EXO-control-induced group and EXO-LPS-induced group. The tissue protein expression levels of IL-1β, TNF-α, and Occludin were measured by Western blot after 12 h. Results: The two samples of C-EXO group and LPS-EXO group was proved to be exosomes. Under a light microscope, the lung tissue of EXO-LPS group showed inflammatory cell infiltration, hemorrhage, interstitial and alveolar edema, and the thickness of alveolar septum. The tissue protein levels of IL-1β and TNF-α in EXO-LPS group were obviously higher than the control group, EXO-control group (1.331±0.203 and 0.274±0.018, 0.892±0.074; 0.800±0.096 and 0.596±0.025, 0.441±0.061; all P<0.05). While the tissue protein levels of Occludin showed the opposite phenomenon (0.251±0.021 and 0.862±0.029, 0.453±0.013; all P<0.05). In vitro, Compared with the C-control group and the EXO-control-induced group, the expression levels of IL-1β and TNF-α increased significantly in the EXO-LPS-induced group (0.900±0.033 and 0.320±0.030, 0.661±0.028; 0.739±0.045 and 0.151±0.024, 0.360±0.037; all P<0.05). whereas the protein levels of Occludin expression were reversed in MLE-12 (0.585±0.082 and 0.941±0.090, 0.732±0.083; all P<0.05). Conclusion: Exosomes derived from LPS-induced RAW264.7 can induced the acute lung injury by affecting barrier function, which probably is related to the low degree of Occludin in alveolar type Ⅱ epithelial cells.

[Characteristics of pulmonary vascular remodeling in rat model of pulmonary hypertension in left heart disease]

Objective: To investigate pulmonary vascular remodeling in rat model of pulmonary hypertension in left heart disease (PH-LHD). Methods: A total of 66 male minor Sprague-Dawley (SD) rats were randomly divided into control group (n=6), sham operation group (n=6) and model group (n=54). The rats in the control group entered the experimental procedure immediately without any treatment, and the rats in the sham operation group entered the experimental procedure 64 days after sham operation, and the rats in model group entered the experimental procedure (6 rats each) on day 1, day 3, day 5, day 8, day 15, day 22, day 36, day 50 and day 64 respectively after supracoronary aortic banding successfully. The lung tissue was fixed and cut and made into pathological sections to observe the characteristics of pulmonary vascular remodeling. Results: Medial thickening was mainly observed in pulmonary arterioles with diameter <100 μm [(11.17±1.03)%]. Additionally, medial thickening was seen in pulmonary arterioles with diameter 50-100 μm and 20-50 μm from day 15 [(12.73±1.15)%] and day 50 [(14.53±1.53)%], respectively. Medial muscularize of pulmonary arterioles were mainly observed in arterioles with diameter 20-50 μm, and deteriorated with time. Reduced pulmonary arteriole lumen size were observed with diameter 20-50 μm since day 50 (P<0.05). Conclusion: Pulmonary arteries with diameter >100 μm have little effect on the reconstruction of pulmonary vessels in PH-LHD rat model. However, arterioles with diameter 20-50 μm and 50-100 μm are the most important vessels involved in the formation of pulmonary hypertension, especially 20-50 μm.

[Feasibility and safety of paclitaxel-eluting balloon for the treatment of de novo coronary lesions]

Objective: To evaluate the safety and feasibility of treating de novo coronary lesions with paclitaxel-eluting balloon. Methods: This is a retrospective study, which enrolled 76 patients with 80 de novo coronary lesions treated with paclitaxel-eluting balloons(<30% residual stenosis and there was no blood flow limited dissection after pretreatment) from April 2015 to November 2016 in Guangdong general hospital. The data of basic characteristics,procedures,devices and follow-up information were retrieved and analyzed. The primary endpoint was the composite of cardiac death, recurrent myocardial infarction and target lesion revascularization. Results: (1)The age was (63.3±10.3) years. There were 68.4%(52/76) acute coronary syndrome patients, prevalence of type 2 diabetes was 36.8%(28/76), and 64.5%(49/76)patients with at least one high bleeding risk. (2)The lesion length was (17.4±7.6)mm, and the stenosis was (88.1±8.2)%.The reference vessel diameter≥2.75 mm accounted for 51.2% (41/80), and bifurcation stenosis accounted for 67.5%(54/80). (3)53.7%(43/80) lesions were pretreated with scoring balloon to optimize plaque modification. The paclitaxel-eluting balloon length and diameter were (22.3±5.5)mm and (2.74±0.52)mm.The residual stenosis was (12.3±10.3)%. Procedural success was 88.8%(71/80).Bail-out stenting rate was 5.0%(4/80). (4)The median follow-up duration was 12(6, 25) months. Primary endpoint occurred in 3 cases (3.9%), including 2 cardiac deaths(1 patient died of recurrent myocardial infarction, and 1 patient died of acute heart failure induced by severe mitral insufficiency), and one patient receivedtarget lesion revascularization. Conclusion: In case of no more than 30% residual stenosis and no blood flow limited dissection after lesion pretreatment,it is safe and feasible to treat de novo coronary lesionsusing paclitaxel-eluting balloon.

The influence of structural isomerism on fluorescence and organic dye selective adsorption in two complexes based on flexible ligands

Based on Cd(NO₃)₂·4H₂O and 4,4'-((5-carboxy-1,3-phenylene)bis(oxy))dibenzoic acid (H₃cpbda), two isomeric coordination polymers, {[Cd_1.5(cpbda)(bpa)(H₂O)₂]·1.5H₂O}_n (1), [Cd(H₂cpbda)₂(bpa)_0.5(H₂O)]_n (2), were synthesized by using different solvent-systems. The complexes were characterized by single-crystal X-ray diffraction, IR spectroscopy, powder X-ray diffraction, and thermogravimetric analysis. Owing to the obvious structural difference between the two isomeric complexes, the further fluorescence sensing and dye selection and adsorption were investigated. The 3D tight stacking structure of 1 strengthened the fluorescence emission and the loose 2D layer structure of 2 generated the active selection and adsorption of the Malachite Green Oxalate (MGO) dye.

S-shaped non-paraxial corrections to general astigmatic beams

Non-paraxial perturbation wave equations are solved for general astigmatic Gaussian beams for the first time, to the best of our knowledge, in the angular spectrum representation by taking into account generic boundary conditions. Expressions for second-order corrections are derived and exemplified with an optical cavity made of two cylindrical mirrors. Non-paraxial corrections can lead, depending on the choice of boundary conditions, to a transverse S-shaped beam mode, which has been qualitatively been observed in a highly divergent non-planar four-mirror cavity.

A novel high power X-band ferrite phase shifter

A novel high power X-band ferrite phase shifter (PS) employing the structure of several waveguides connected in parallel is proposed. Each of the waveguides is a phase shift unit utilizing a dual-toroid structure. First, the phase shift unit is designed, manufactured, and tested. The results indicate that the power capacity reaches 115 kW. At this power, the maximum magnetic field strength of ferrite is 7.9 kA/m, beyond which the nonlinear effect of ferrite will occur. On this basis, the PS that consists of four units connected in parallel is designed. According to the threshold of ferrite, the power capacity of the PS can theoretically reach 430 kW. Limited by the maximum output power of the microwave source, the preliminary high-power test results demonstrate that the PS can operate properly at 270 kW. The PS exhibits an insertion loss of 0.82 dB and a maximum differential phase shift of approximately 300° at 9.3 GHz. The return loss of the PS is more than 16 dB from 9.0 to 9.5 GHz.

[The spontaneous herniation of temporomandibular joint into external auditory canal: diagnosis of otoscopy, CT and MRI]

OBJECTIVE

To summarize the otoscopy, CT and MRI features of spontaneous herniation of the temporomandibular joint(TMJ) into the external auditory canal(EAC) through the persistence Huschke's foramen(PHF).

METHODS

The otoscopy, CT and MRI images of three cases with the herniation of the TMJ into the EAC through the PHF were analyzed retrospectively.

RESULTS

Otoscopy revealed the masses located in the antero-inferior aspect of the bony EAC, and the mass displayed an alternative of forward and backward motion during opening and closing of the mouth.CT of the temporal bone showed a bony defect and a consecutive soft mass in the antero-inferior wall of the bony EAC. The margin of the bony defects were well-defined in all cases, the bone adjacent to PHF was pressed and partially wrapped around the soft mass as 'holding ball' in two cases, partly peripheral pseudo bony shell of the soft mass were showed in two cases. The soft mass in EAC appeared equal attenuated with the soft tissue of TMJ, and on enhanced CT scans showed no enhancement of the soft mass. On MRI scans, the imaging displayed a bony defect in the antero-inferior wall of the EAC with a soft mass which was formed by the capsule of the TMJ, and the mass showed iso-signal to the capsule of the TMJ on all sequences, and there was no enhancement after contrast administration.

CONCLUSION

The otoscopy, CT and MRI features of the spontaneous herniation of the TMJ into the EAC through the PHF is special, and the above examinations are valuable for diagnosis of the disease.

Compact high-power microwave divider and combiner

A novel, compact, TM01-TE10 mode power divider and a novel, compact, four-way TE10-TM01 mode power combiner were theoretically designed and experimentally tested as a proof of principle. The theoretical and experimental S parameters are consistent with each other. High-power experiments show that their power capacities are no less than 1.5 GW and 3 GW, respectively. The devices have the merits of high power capacities and low insertion losses.

Association between IL2/IL21 and SH2B3 polymorphisms and risk of celiac disease: a meta-analysis

Celiac disease (CD) is a common autoimmune disorder characterized by heightened immunological response to ingested gluten. Certain gene polymorphisms of IL2/IL21 (rs6822844 and rs6840978) and SH2B3 (rs3184504) may influence susceptibility to CD, although the effects remain unclear. We performed a meta-analysis of the associations between rs6822844, rs6840978, and rs3184504 polymorphisms and CD risk. PubMed, EMBASE, and the China National Knowledge Infrastructure were searched. ORs and 95%CIs of each single nucleotide polymorphism (SNP) were estimated using the fixed-effect model if I(2) < 50% in the test of heterogeneity; otherwise, the random-effect model was used. Our meta-analysis included 12,986 CD cases and 28,733 controls from 16 independent samples, and the analysis of each SNP contained a subset of the total. We found that the minor allele T of both rs6822844 (T vs G, OR = 0.72, 95%CI = 0.67-0.78, P < 0.001) and rs6840978 (T vs C, OR = 0.76, 95%CI = 0.71-0.83, P < 0.001) in IL2/IL21 significantly decreased the risk of CD. However, the minor allele A of rs3184504 (A vs G, OR = 1.18, 95%CI = 1.12-1.24, P < 0.001) in SH2B3 significantly increased CD susceptibility. The estimated lambda values were 0.49, 0.50, and 0.53 for rs6822844, rs6840978, and rs3184504, respectively, suggesting that a co-dominant model of genotype effect was most appropriate for the three SNPs. Our results support associations between the three SNPs and CD and provide a strong argument for further research.

Association of TLR2 and TLR4 non-missense single nucleotide polymorphisms with type 2 diabetes risk in a southern Chinese population: a case-control study

Toll-like receptors (TLRs), the triggers of the innate and adaptive immune responses, are involved in the pathogenesis of type 2 diabetes mellitus (T2DM). Several studies have investigated the effects of genetic polymorphisms in TLR4 and TLR2, but they have yielded limited results. We investigated whether non-missense genetic polymorphisms in the regulatory regions of TLR4 and TLR2 were related to T2DM in a southern Chinese population. Single nucleotide polymorphisms (SNPs) in TLR4 (rs1927911, rs11536889, rs1927907, rs1927906, rs1927914, rs7873784, and rs2149356) and TLR2 (rs1898830, rs3804099, rs4696480, and rs3804100) were genotyped in 552 T2DM and 552 unrelated age- and gender-matched controls by SNaPShot Multiplex assay. Genotypes GG (OR = 0.09, 95%CI = 0.01- 0.83, P = 0.03) and CG (OR = 0.08, 95%CI = 0.01-0.74, P = 0.03) of the 3'-untranslated region (UTR) SNP rs7873784 in TLR4, and genotype AG (OR = 0.67, 95%CI = 0.46-0.97, P = 0.04) and allele G (OR = 0.88, 95%CI = 0.79-0.97, P = 0.01) of the intron SNP rs1898830 in TLR2 were identified as protective against the development of T2DM in southern Chinese people. In contrast, a meta-analysis of rs1927911 and rs1927914 showed no association. Haplotypes AGTT (OR = 0.34, 95%CI = 0.15-0.77, P = 0.01) and AATT (OR = 1.20, 95%CI = 1.01- 1.44, P = 0.05) in TLR2 were significantly associated with susceptibility to T2DM. Our results suggest that the effects of non-missense polymorphisms located in the regulatory regions of TLR4 and TLR2 should not be neglected in T2DM association analysis.

Environmental and DNA repair risk factors for breast cancer in South China

PURPOSE

The incidence of breast cancer (BC) in China has been rapidly increasing. We hypothesize that China-specific risk factors, both life-style and inherent ones, contribute to the problem.

METHOD

We have conducted an epidemiology and functional DNA repair investigation to identify risk factors for the development of BC in Shantou, China.

RESULTS

Our survey of 372 patients and 419 matched normal controls confirmed the significant risk from many universal factors: high BMI, low education level, low fruit intake and sedate lifestyle. Significant risk factors can be organized into endogenous ones (low education and cooking with lard instead of vegetable oil) and externally-introduced ones (sedate life-style and cigarette smoking). We also found highly significant risk from passive exposure to cigarette smoke. Using the Challenge-Comet assay and blood samples from 57 patients who did not inherit the tumor suppressor BRCA gene mutations and 62 matched normal controls; we showed that reduced functional DNA repair capacity was a significant risk factor. In addition, the reduced repair capacity was associated with lymph node metastasis, and with tumors that had negative ER receptor and over-expression of Her-2.

CONCLUSION

Our study indicates that combined externally-introduced and endogenous life-style factors were involved with the increased incidence of BC in China. We also showed, for the first time, that inherent deficiency in DNA repair function was a significant risk factor for BC. The inherent deficiency can interact with other risk factors to significantly increase risk for BC. In addition, the reduced repair capacity was associated with certain clinical features that are indicative of poor prognosis. In this context, it is possible to integrate DNA repair capacity knowledge in promoting prevention of BC and in enhancing personalized therapeutic protocols.

A stable 3D porous coordination polymer as multi-chemosensor to Cr(iv) anion and Fe(iii) cation and its selective adsorption of malachite green oxalate dye

A 3D porous coordination polymer was synthesized by three solvent-thermal methods. The sensing and titration experiments show that it can detect Fe(iii) cation and Cr(vi) anions (Cr₂O₇²⁻ or CrO₄²⁻). Besides, it can selectively adsorb the malachite green oxalate dye.

High finesse pulsed optical cavity locking by tilt-locking technique

We report the Tilt-Locking (TL) technique applied to lock a laser in pulsed regime to a 28,000 high finesse Fabry-Perot cavity. Preliminary experimental results show that TL technique is comparable with the well-known Pound-Drever-Hall technique. This study is the first to implement the TL technique to lock a pulsed laser to a high-finesse optical cavity. Very high and stable coupling is obtained. The coupling rate is ~80%, and locking can last for more than 1 h. Furthermore, while previously published papers have focused on near field case, in this study we will give the error signal shape simulation for the far field case. We will show that for different types of error sources, the split photodiode transverse position can be carefully adjusted to obtain a symmetrical error signal. Our experimental results are consistent with the simulations.

A simple scheme for injection and extraction in compact rings

There has been great interest in building compact synchrotrons for various applications, for example, inverse Compton scattering X-ray sources. However, the beam injection and extraction in compact rings require careful design for the lack of space. In this paper, we propose a simple combined injection-extraction scheme exploiting the fringe field of existing dipole magnets instead of additional septum magnets. This scheme is illustrated by using the 4.8 m ring proposed for Tsinghua Thomson scattering X-ray source as an example. Particle tracking is applied to demonstrate the validity of this scheme.

Phase-space dynamics of ionization injection in plasma-based accelerators

The evolution of beam phase space in ionization injection into plasma wakefields is studied using theory and particle-in-cell simulations. The injection process involves both longitudinal and transverse phase mixing, leading initially to a rapid emittance growth followed by oscillation, decay, and a slow growth to saturation. An analytic theory for this evolution is presented and verified through particle-in-cell simulations. This theory includes the effects of injection distance (time), acceleration distance, wakefield structure, and nonlinear space charge forces, and it also shows how ultralow emittance beams can be produced using ionization injection methods.

Generating high-brightness electron beams via ionization injection by transverse colliding lasers in a plasma-wakefield accelerator

The production of ultrabright electron bunches using ionization injection triggered by two transversely colliding laser pulses inside a beam-driven plasma wake is examined via three-dimensional particle-in-cell simulations. The relatively low intensity lasers are polarized along the wake axis and overlap with the wake for a very short time. The result is that the residual momentum of the ionized electrons in the transverse plane of the wake is reduced, and the injection is localized along the propagation axis of the wake. This minimizes both the initial thermal emittance and the emittance growth due to transverse phase mixing. Simulations show that ultrashort (~8 fs) high-current (0.4 kA) electron bunches with a normalized emittance of 8.5 and 6 nm in the two planes, respectively, and a brightness of 1.7×10(19) A rad(-2) m(-2) can be obtained for realistic parameters.

Generating ultrabroadband terahertz radiation based on the under-compression mode of velocity bunching

We propose and analyze a scheme to generate enhanced ultrabroadband terahertz (THz) radiation through coherent transition radiation emitted by ultrashort electron beams based on a 10.5 m beamline at Tsinghua University. The proposed scheme involves the initial compression of the electron beam with a few hundred pC charges using a velocity bunching scheme (i.e., RF compression) in an under-compression mode instead of the usual critical-compression mode in order to maintain a positive energy chirp at the exit of the traveling wave accelerator. After a long drift segment, the particles in the tail catch up with the bunch head. More than 80% of the particles are distributed in a spike with an rms length less than 20 fs. Such beams correspond to an ultrabroadband coherent transition radiation (CTR) spectrum of 0.1 THz to 25 THz, with the single-pulse THz radiation energy of up to 50 μJ. The principle of CTR and under-compression mode of velocity bunching are introduced in this paper. And the ASTRA simulation parameters and the stability of the system are also discussed.