The structure and working principle of the multi-leaf collimator(MLC)optical system of Elekta linear accelerator were introduced.The causes for the faults of the MLC optical system were analyzed,and the fault repair and maintenance of the MLC optical system were summarized.References were provided for medical engineers to repair and maintain the MLC optical system.[Chinese Medical Equipment Journal,2024,45(1):76-83]

Objective: To learn the status and influencing factors of development among infants at ages of 0 to 36 months in Xiaoshan District, Hangzhou City, so as to provide the reference for promoting healthy development of infants. Methods: Infants at ages of 0-36 months who underwent physical examination in Child Health Clinic of Xiaoshan District Community Health Service Center were selected in 2022. General data of infants and their mothers were collected through questionnaires, and the development status of infants was screened by Age and Stages Questionnaire (third edition). Factors affecting the development status were identified using a multivariable logistic regression model. Results: A total of 2 519 infants were investigated, including 1 339 males (53.16%) and 1 180 females (46.84%). There were 608 infants with abnormal development of at least one functional area of communication (CM), gross motor (GM), fine motor (FM), problems solving (CG) and personal-social (PS). The abnormal rate was 24.14%, and the abnormal rates of the above functional areas were 9.77%, 6.59%, 7.98%, 6.39% and 9.33%, respectively. Multivariable logistic regression analysis showed that gender (male, OR=1.563, 95%CI: 1.191-2.052), mother's childbearing age (≥35 years, OR=1.411, 95%CI: 1.001-1.988), mother's educational level (lower than junior college, OR=1.460, 95%CI: 1.116-1.912) were factors affecting abnormal development of CM; preterm birth (OR=2.323, 95%CI: 1.315-4.103) was factors affecting abnormal development of GM; gender (male, OR=1.654, 95%CI: 1.225-2.232) was factors affecting abnormal development of FM; gender (male, OR=1.511, 95%CI: 1.086-2.102) and mode of delivery (cesarean section, OR=1.460, 95%CI: 1.060-2.010) were factors affecting abnormal development of CG; gender (male, OR=1.340, 95%CI: 1.019-1.763) and birth weight (low birth weight, OR=1.985, 95%CI: 1.149-3.432) were factors affecting abnormal development of PS. Conclusions The rate of abnormal development among infants at ages of 0 to 36 months in Xiaoshan District is 24.14%. Gender, preterm birth, mode of delivery, birth weight, mother's childbearing age and mother's educational level could affect the development status of infants.

Sulfur dioxide(SO2)is involved in regulating various physiological processes of blood vessels,such as maintaining normal vascular structure,regulating vascular tension,controlling blood pressure,inhibiting vascular cell proliferation,regulating apoptosis and autophagy.In pathophysiological conditions such as hypertension,pulmonary hypertension and atherosclerosis,SO2 plays a protective role in pathological changes through different molecular mechanisms.In this paper,we will review the endogenous SO2 production and metabolism,vascular biological effects and its regulation on blood vessels.

Hydrogen sulfide(H2S)is an emerging endogenous neuromodulator that holds significant potential in the realm of neurological diseases.Its role encompasses reducing neuronal damage,inhibiting excessive activation of striatal astrocytes,and regulating cerebrovascular function,among other physiopathological pathways.Conversely,microRNAs(miRNAs)are widely recognized as pivotal regulators of neurological diseases.They primarily target the 3'untranslated region of the target gene mRNA,impeding mRNA translation and hindering its expression to impart neuroprotective effects.Recent findings have underscored the crucial involvement of H2S and miRNAs in the pathogenesis of various neurological disorders such as Parkinson's disease,stroke,and spinal cord diseases,thereby garnering significant attention.This paper comprehensively summarizes the protective effects arising from the interplay between H2S and miRNAs in neurological diseases,while also delving into the potential therapeutic efficacy they hold for such conditions.

Objective To develop a biological safety protection third-level(BSL-3)laboratory based on folding-modular shelters to solve the problems of the existing laboratories in space and function expansion,large-scale deployment and low-cost transportation.Methods The BSL-3 laboratory was composed of a folding combined shelter module,a ventilation and purification module,a power supply and distribution module,a monitoring and communication module,a control system module and an equipment module.The folding combined shelter module used a leveling base frame as the foundation and a lightweight panel as the enclosure mechanism,and was divided into an auxiliary area and a protection protected area;the ventilation and purification module was made up of an air supply unit and an air exhaust unit,the air supply unit was integrated with a fresh-air air conditioner and the exhaust unit was equipped with a main fan,a standby fan and a bag in/bag out filter;the control system module adopted a supervision mode of decentralized control and centralized management,which executed communication with the data server as the center and Profinet protocol and MODBUS-TCP.Results The BSL-3 laboratory proved to meet the requirements of relevant standards in internal microenvironment,airflow direction,airtightness,working condition and disinfection effect.Conclusion The BSL-3 laboratory is compatible with large-scale transport and deployment and facilitates reliable and safe experiments for epidemic prevention and control and cross-regional support.[Chinese Medical Equipment Journal,2024,45(3):41-46]

Objective To construct a risk prediction model for healthcare-associated infection(HAI)in stroke pa-tients,accurately and effectively screen out potential high-risk groups,and formulate targeted preventive interven-tions to reduce the occurrence of infection.Methods Stroke patients in the"Henan Stroke Cohort"in 2019-2021 were selected as the study objects,and relevant clinical data were collected as the main analysis data for model con-struction and internal validation.The relevant data of stroke patients in three hospitals that had never participated in the cohort construction from January to September 2022 were randomly selected as a test set for external validation of the risk prediction model.The main analysis data were randomly divided into a training set and a test set,and a risk prediction model was constructed based on logistic regression,artificial neural network(ANN)algorithm,extreme gradient boosting algorithm and random forest algorithm,respectively.Multiple indicators were used to evaluate the prediction performance of the model,and the optimal model was externally validated based on the test set data.Results The infection rate of stroke patients was 20.6％in the main analysis data and 56.4％in the test set data.The accuracy of the risk prediction model based on logistic regression was 91.2％,the area under the re-ceiver operating characteristic(ROC)curve(AUC)was 0.938,the precision rate,recall rate,specificity,and the F1 score were 0.851,0.695,0.968,and 0.765,respectively.The accuracy rate,precision rate,specificity and AUC of the logistic risk prediction model and the ANN risk prediction model were all significantly better than other models,while the recall rate and F1 score of the logistic risk prediction model were slightly better than the ANN risk prediction model.The logistic risk prediction model had excellent prediction performance in external validation.Conclusion HAI risk prediction model of stroke patients based on logistic regression can better screen out high-risk stroke patients with infection risk,and can contribute to formulate targeted preventive interventions to reduce the occurrence of infection.

Objective: To describe the distribution characteristics of hypertension among adult twins in the Chinese National Twin Registry (CNTR) and to provide clues for exploring the role of genetic and environmental factors on hypertension. Methods: A total of 69 220 (34 610 pairs) of twins aged 18 and above with hypertension information were selected from CNTR registered from 2010 to 2018. Random effect models were used to describe the population and regional distribution of hypertension in twins. To estimate the heritability, the concordance rates of hypertension were calculated and compared between monozygotic twins (MZ) and dizygotic twins (DZ). Results: The age of all participants was (34.1±12.4) years. The overall self-reported prevalence of hypertension was 3.8%(2 610/69 220). Twin pairs who were older, living in urban areas, married, overweight or obese, current smokers or ex-smokers, and current drinkers or abstainers had a higher self-reported prevalence of hypertension (P<0.05). Analysis within the same-sex twin pairs found that the concordance rate of hypertension was 43.2% in MZ and 27.0% in DZ, and the difference was statistically significant (P<0.001). The heritability of hypertension was 22.1% (95%CI: 16.3%- 28.0%). Stratified by gender, age, and region, the concordance rate of hypertension in MZ was still higher than that in DZ. The heritability of hypertension was higher in female participants. Conclusions: There were differences in the distribution of hypertension among twins with different demographic and regional characteristics. It is indicated that genetic factors play a crucial role in hypertension in different genders, ages, and regions, while the magnitude of genetic effects may vary.
Adult ; Female ; Humans ; Male ; Alcohol Drinking ; Diseases in Twins/genetics* ; Hypertension/genetics* ; Twins, Dizygotic/genetics* ; Twins, Monozygotic/genetics*

Objective: To describe the distribution characteristics of hyperlipidemia in adult twins in the Chinese National Twin Registry (CNTR) and explore the effect of genetic and environmental factors on hyperlipidemia. Methods: Twins recruited from the CNTR in 11 project areas across China were included in the study. A total of 69 130 (34 565 pairs) of adult twins with complete information on hyperlipidemia were selected for analysis. The random effect model was used to characterize the population and regional distribution of hyperlipidemia among twins. The concordance rates of hyperlipidemia were calculated in monozygotic twins (MZ) and dizygotic twins (DZ), respectively, to estimate the heritability. Results: The age of all participants was (34.2±12.4) years. This study's prevalence of hyperlipidemia was 1.3% (895/69 130). Twin pairs who were men, older, living in urban areas, married,had junior college degree or above, overweight, obese, insufficient physical activity, current smokers, ex-smokers, current drinkers, and ex-drinkers had a higher prevalence of hyperlipidemia (P<0.05). In within-pair analysis, the concordance rate of hyperlipidemia was 29.1% (118/405) in MZ and 18.1% (57/315) in DZ, and the difference was statistically significant (P<0.05). Stratified by gender, age, and region, the concordance rate of hyperlipidemia in MZ was still higher than that in DZ. Further, in within-same-sex twin pair analyses, the heritability of hyperlipidemia was 13.04% (95%CI: 2.61%-23.47%) in the northern group and 18.59% (95%CI: 4.43%-32.74%) in the female group, respectively. Conclusions: Adult twins were included in this study and were found to have a lower prevalence of hyperlipidemia than in the general population study, with population and regional differences. Genetic factors influence hyperlipidemia, but the genetic effect may vary with gender and area.
Adult ; Female ; Humans ; Male ; Middle Aged ; Young Adult ; China/epidemiology* ; Diseases in Twins/genetics* ; Hyperlipidemias/genetics* ; Metabolic Diseases ; Twins, Dizygotic ; Twins, Monozygotic/genetics*

Objective: To evaluate the efficacy and safety of different medical treatment in advanced or unresectable angiosarcoma. Methods: This study was a single-center retrospective clinical study. Fifty-five advanced or unresectable angiosarcoma patients treated in Sun-Yat Sen University Cancer Center from January 2005 to August 2020 were enrolled. There were 34 patients who received first-line doxorubicin-based chemotherapy (doxorubicin group), 12 patients received first-line doxorubicin or liposome doxorubicin plus paclitaxel or albumin bound paclitaxel chemotherapy (combination therapy group), and 4 patients received first-line paclitaxel-based treatment (paclitaxel group). There were 6 patients who received anti-angiogenesis targeted therapy, another 2 patients received anti-PD-1 antibody plus anti-angiogenesis targeted therapy. Targeted therapy and immunotherapy plus targeted therapy included 5 cases of first-line therapy and 3 cases of second-line therapy. The therapeutic effect was evaluated by RECIST 1.1 standard. The adverse reactions were evaluated by CTCAE4.0 standard. Kaplan-Meier survival analysis was evaluated with Log rank test. Cox proportional hazard model was used to analyze the influencing factors. Results: There were 18 patients achieved partial response (PR) in 34 patients in the doxorubicin group, median progression-free survival (mPFS) was 4.5 months, and median overall survival (mOS) was 15 months. Four patients achieved PR in 12 patients in the combination therapy group, mPFS and mOS were 4 months and 19 months. Two patients achieved PR in 4 patients in the paclitaxel group, mPFS and mOS were 3 months and 9 months. However, only 1 in 6 patients achieved PR for anti-angiogenesis targeted therapy, mPFS and mOS were 3 months and 16 months. Two patients who received anti-PD-1 immunotherapy combined with anti-angiogenesis targeted therapy acquired PR for 17 months and more than 16 months. Median PFS (7.5 months) were longer in those with primary liver, lung and spleen angiosarcoma than in those with other primary site (3.0 months, P=0.028). The mOS (20 months) was longer in females than that in males (12 months, P=0.045). Primary tumor site, sex, age and treatment were not independent prognostic factors for angiosarcoma patients (P>0.05). Grade 3-4 cardiac toxicity was found in 2 patients in the combination therapy group. Conclusions: Doxorubicin-based and paclitaxel-based chemotherapy are the most important treatment for advanced angiosarcoma. Potential efficacy for targeted therapy combined with anti-PD-1 immunotherapy are showed in some patients with long duration of response and moderate adverse event.
Male ; Female ; Humans ; Hemangiosarcoma ; Retrospective Studies ; Paclitaxel/adverse effects* ; Doxorubicin/therapeutic use* ; Antineoplastic Combined Chemotherapy Protocols/adverse effects*

Objective: To analyze the prevalence and the risk factors of fungal sepsis in 25 neonatal intensive care units (NICU) among preterm infants in China, and to provide a basis for preventive strategies of fungal sepsis. Methods: This was a second-analysis of the data from the "reduction of infection in neonatal intensive care units using the evidence-based practice for improving quality" study. The current status of fungal sepsis of the 24 731 preterm infants with the gestational age of <34⁺⁰ weeks, who were admitted to 25 participating NICU within 7 days of birth between May 2015 and April 2018 were retrospectively analyzed. These preterm infants were divided into the fungal sepsis group and the without fungal sepsis group according to whether they developed fungal sepsis to analyze the incidences and the microbiology of fungal sepsis. Chi-square test was used to compare the incidences of fungal sepsis in preterm infants with different gestational ages and birth weights and in different NICU. Multivariate Logistic regression analysis was used to study the outcomes of preterm infants with fungal sepsis, which were further compared with those of preterm infants without fungal sepsis. The 144 preterm infants in the fungal sepsis group were matched with 288 preterm infants in the non-fungal sepsis group by propensity score-matched method. Univariate and multivariate Logistic regression analysis were used to analyze the risk factors of fungal sepsis. Results: In all, 166 (0.7%) of the 24 731 preterm infants developed fungal sepsis, with the gestational age of (29.7±2.0) weeks and the birth weight of (1 300±293) g. The incidence of fungal sepsis increased with decreasing gestational age and birth weight (both P<0.001). The preterm infants with gestational age of <32 weeks accounted for 87.3% (145/166). The incidence of fungal sepsis was 1.0% (117/11 438) in very preterm infants and 2.0% (28/1 401) in extremely preterm infants, and was 1.3% (103/8 060) in very low birth weight infants and 1.7% (21/1 211) in extremely low birth weight infants, respectively. There was no fungal sepsis in 3 NICU, and the incidences in the other 22 NICU ranged from 0.7% (10/1 397) to 2.9% (21/724), with significant statistical difference (P<0.001). The pathogens were mainly Candida (150/166, 90.4%), including 59 cases of Candida albicans and 91 cases of non-Candida albicans, of which Candida parapsilosis was the most common (41 cases). Fungal sepsis was independently associated with increased risk of moderate to severe bronchopulmonary dysplasia (BPD) (adjusted OR 1.52, 95%CI 1.04-2.22, P=0.030) and severe retinopathy of prematurity (ROP) (adjusted OR 2.55, 95%CI 1.12-5.80, P=0.025). Previous broad spectrum antibiotics exposure (adjusted OR=2.50, 95%CI 1.50-4.17, P<0.001), prolonged use of central line (adjusted OR=1.05, 95%CI 1.03-1.08, P<0.001) and previous total parenteral nutrition (TPN) duration (adjusted OR=1.04, 95%CI 1.02-1.06, P<0.001) were all independently associated with increasing risk of fungal sepsis. Conclusions: Candida albicans and Candida parapsilosis are the main pathogens of fungal sepsis among preterm infants in Chinese NICU. Preterm infants with fungal sepsis are at increased risk of moderate to severe BPD and severe ROP. Previous broad spectrum antibiotics exposure, prolonged use of central line and prolonged duration of TPN will increase the risk of fungal sepsis. Ongoing initiatives are needed to reduce fungal sepsis based on these risk factors.
Infant ; Infant, Newborn ; Humans ; Birth Weight ; Intensive Care Units, Neonatal ; Retrospective Studies ; Tertiary Care Centers ; Infant, Extremely Low Birth Weight ; Gestational Age ; Infant, Extremely Premature ; Sepsis/epidemiology* ; Retinopathy of Prematurity/epidemiology* ; Bronchopulmonary Dysplasia/epidemiology*