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The large deuterium/tritium target is the key component to achieve high yield and high current neutron source, which is the precondition for the wide application of deuterium/tritium neutron source. At present, there are mature deuterium/tritium titanium targets in scientific or engineering applications abroad, and the neutron yield generally reaches the level of 1013/s. However, the technology of large-area target film in China is immature. The scientific and industrial application of large-area target film is rarely reported. The main problem is that the deuterium/tritium target can not reach the high yield, and the large area of the target film prepared is uneven, the binding force is poor and easy to fall off. In this paper, in order to solve the above mentioned problems and optimize the performance of the target film, magnetron sputtering coating and multi-arc ion plating were combined to prepare large-area titanium films with copper or molybdenum substrate and diameter greater than φ500 mm. At the same time, the feasibility of erbium film, scandium film and zirconium film preparation was explored by preparing large area deuterium-titanium or tritium-titanium targets with high binding force and high deuterium-tritium-titanium ratio. Deuterium and tritium targets with deuterium/tritium titanium ratio greater than 1.85 are produced by using self-developed deuterium/tritium target production system after degassing, purification, high temperature deuterium absorption, tail gas recovery and other processes. In order to better utilize the functions of each film layer, scanning electron microscopy was used to observe the cross-section of the film layer in the experiment. The results show that the clear interface is observed among the base layer, transition layer, and functional layer. The prepared titanium film was tested for neutron yield using a deuterium ion accelerator, and the effects of deuterium ion beam current and anode voltage on neutron yield were analyzed. The experiment shows that with the increase of deuterium beam current, neutron yield shows a linear increase in the range of 700 μA. The effect of anode acceleration voltage on neutron yield increases exponentially in a quadratic relationship. The neutron yield of the developed deuterium target is more than 8.0×108/s, and the neutron yield of the tritium target is estimated according to the reaction section of the deuterium target and the tritium target. Under the same conditions, the neutron yield of the tritium target is more than 1.0×1011/s. The test results show that the developed φ500 mm large area deuterium/tritium target can achieve the high-yield neutron output of the high-current neutron source, reaching the highest neutron flux of 1013/s in the world.

IntroductionIbuprofen is one of the most common non-steroidal anti-inflammatory drugs used to close patent ductus arteriosus (PDA) in preterm infants. PDA is associated with bronchopulmonary dysplasia (BPD), while PDA closure by ibuprofen did not reduce the incidence of BPD or death. Previous studies have indicated an anti-angiogenesis effect of ibuprofen. This study investigated the change of angiogenic factors after ibuprofen treatment in preterm infants.MethodsPreterm infants with hemodynamically significant PDA (hsPDA) were included. After confirmed hsPDA by color doppler ultrasonography within 1 week after birth, infants received oral ibuprofen for three continuous days. Paired plasma before and after the ibuprofen treatment was collected and measured by ELISA to determine the concentrations of platelet-derived growth factor-BB (PDGF-BB) and vascular endothelial growth factor A (VEGF-A), and hypoxia-inducible factor-2α (HIF-2α).Results17 paired plasma from infants with hsPDA were collected. The concentration of PDGF-BB and VEGF-A significantly decreased after ibuprofen treatment (1,908 vs. 442 pg/mL for PDGF-BB, 379 vs. 174 pg/mL for VEGF-A). HIF-2α level showed a tendency to decrease after ibuprofen treatment, although the reduction was not statistically significant (p = 0.077).ConclusionThis study demonstrated decreased vascular growth factors after ibuprofen exposure in hsPDA infants.

Cooling technology is widely applied in modern turbines to protect the turbine blades, and extracting high-pressure cooling air from a compressor exerts a remarkable influence on the gas-turbine performance. However, the three-dimensional optimal design of a turbine in modern industrial practice is usually carried out by pursuing high component efficiency without considering possible changes in coolant requirement; hence, it may not exactly lead to improvement in the gas-turbine cycle efficiency. In this study, the turbine stator was twisted and leaned to achieve higher comprehensive efficiency, which is the cycle-based efficiency definition for a cooled turbine that considers both turbine aerodynamic performance and coolant requirement. First, the influence of twist and compound lean on turbine aerodynamic performance, considering stator-hub leakage, was investigated. Then, a method to predict the coolant requirement for turbines with different stator designs was applied, to evaluate coolant-requirement change at the design condition. The optimized turbines were finally compared to demonstrate the necessity of considering the coolant-requirement change in the optimal design. This indicated that proper twisting to open the throat area in the stator hub and compound lean to the pressure surface side could help improve the cooled-turbine comprehensive efficiency.

Abstract Background The causes of birth defects (BDs) are complex and include genetic and environmental factors and/or their interactions. More research is needed to describe the epidemiology of BDs within specific regions of China. This study focused on differences in the prevalence of BDs based on ethnicity in a large city in Guangxi Province, China. Methods Surveillance data of infants born in 114 registered hospitals in Liuzhou between 2011 and 2015 were analyzed to determine the epidemiology of BDs across five major ethnic groups. We calculated the prevalence of BDs and relative risk of BDs by ethnicity. Results There were 260,722 perinatal infants of which 6581 had BDs, with the average prevalence of 25.24 per 1000 perinatal infants (PIs). Prevalence data showed an obvious uptrend over the past 5 years. Han had the highest prevalence of total BDs (28.98‰), followed by Zhuang (25.19‰), Yao (18.50‰), Miao (15.78‰) and Dong (14.24‰). Relative to the Han; Zhuang, Miao, Yao, and Dong had a lower risk of musculoskeletal and urogenital malformations; Miao and Yao had a lower risk of cardiovascular malformation; and Dong had a lower risk of cardiovascular and craniofacial malformation. Several maternal risk factors were found to be associated with BDs (e.g., maternal and gestational age, number of antenatal care visits). Conclusion This study provided a comprehensive description of ethnic differences in the risk of BDs in Liuzhou City, China. Observed ethnic differences in the risk of BDs may be related to genetic susceptibilities, environment, cultural customs, or to potential combinations of these factors.

Abstract Background Although the majority of Candida infections occur in the developing world, candidemia epidemiology is poorly understood in these countries. The aim of this study was to investigate the epidemiology of non-Candida albicans (non-C. albicans) candidemia among neonates at Liuzhou Maternity and Child Healthcare Hospital in China. Methods A retrospective review of all positive blood culture about Candida species in neonatal intensive care unit was conducted between January 2012 and November 2015. Information about demographics, risk factors and outcome of candidemia were collected. Univariate and multivariate logistic regression models were used to identify the risk factors associated with the development of non-C.albicans candidemia. Results The prevalence of candidemia in infants was 1.4%. Non-C.albicans was responsible for 56.5% of neonatal candidemia. The predisposing factors for development of non-C.albicans candidemia among infants included mechanical ventilation [odds ratio (OR), 95% confidence interval (95%CI) = 3.13, 1.07–9.14; P = 0.037] and use of assisted reproductive technology (OR, 95%CI = 4.52, 1.39–14.77; P = 0.012). The overall mortality rate of candidemia was 8.7% and non-C.albicans attributed to 83.3% of all mortalities. Conclusions Non-C.albicans species are the major cause of candidemia in local neonatal group. The study highlights the urgent needs to evaluate the possibility of development of non-C.albicans candidemia in neonates exposed to these risk factors and much emphasis must be laid on the early implementation of medical intervention to reduce the incidences of candidemia in neonates.

Abstract Background The prevalence and clinical characteristics of neonatal candidemia are poorly understood in western China. The aim of our study was to evaluate the epidemiological features of neonatal candidemia in the Liuzhou Maternity and Child Healthcare Hospital. Methods A retrospective case-control study was conducted between January 2012 and November 2015. Electronic databases were reviewed and data on Candida species were isolated from blood cultures and candidemia incidence, risk factors, and mortality were extracted. Univariate and multivariate logistic regression analysis were performed to identify risk factors associated with candidemia. Results During the 4-year period, candidemia was identified in 69 newborns, for an incidence rate of 13.6 per 1000 admissions. Prolonged antibiotic therapy duration [odds ratio (OR), 95% confidence incidence (95% CI) = 1.06, 1.01–1.10], total parenteral nutrition [OR, 95% CI = 6.03, 2.10–17.30] and neurodevelopmental impairment (OR, 95% CI = 7.34, 1.18–45.80) were all associated with increased odds of candidemia development in infants (P value was 0.010, 0.001, 0.033, respectively). The overall mortality rate was 7.2% in the candidemia group. Conclusions Prolonged duration of antibiotic therapy, presence of total parenteral nutrition and neurodevelopmental impairment were the major risk factors associated with neonatal candidemia. This study highlights the importance of the early detection, diagnosis and treatment of neonatal candidemia.

A novel internal model control (IMC) method for wave rotor refrigeration process (WRRP) based on Harris hawks optimization (HHO) is presented in this paper. Firstly, an identification model is established by the test data of the WRRP. In order to reduce the complexity of the model, the Routh order reduction method was used to reduce the order of the identification model. This procedure yields an approximate second order model with time delay for the WRRP. Secondly, an IMC method based on HHO is proposed after analyzing the time delay characteristics of the WRRP model. This method improves the traditional IMC structure, and introduces a three degree of freedom IMC structure. The parameters of the controller are optimized by HHO to make the comprehensive performance index of the system reach the best. Simulation results demonstrate that the proposed method can achieve a good performance of tracking and disturbance rejection. [ABSTRACT FROM AUTHOR]