A Positioning System based on Communication Satellites and the Chinese Area Positioning System(CAPS)

The Chinese Area Positioning System （CAPS） is a positioning system based on satellite communication that is fundamentally different from the 3＂G＂ （GPS, GLONASS and GALILEO） systems. The latter use special-purpose navigation satellites to broadcast navigation information generated on-board to users, while the CAPS transfers ground-generated navigation information to users via the communication satellite. In order to achieve accurate Positioning, Velocity and Time （PVT）, the CAPS employs the following strategies to over- come the three main obstacles caused by using the communication satellite： （a） by real-time following-up frequency stabilization to achieve stable frequency; （b） by using a single carrier in the transponder with 36 MHz band-width to gain sufficient power; （c） by incorporating Decommissioned Geostationary Orbit communication satellite （DGEO）, barometric pressure and Inclined Geostationary Orbit communication satellite （IGSO） to achieve the 3-D posi- tioning. Furthermore, the abundant transponders available on DGEO can be used to realize the large capacity of communication as well as the integrated navigation and communication. With the communication functions incorporated, five new functions appear in the CAPS： （1） combination of navigation and communication; （2） combination of navigation and high accu- racy orbit measurement; （3） combination of navigation message and wide/local area differen- tial processing; （4） combination of the switching of satellites, frequencies and codes; and （5） combination of the navigation message and the barometric altimetry. The CAPS is thereby labelled a PVT5C system of high accuracy. In order to validate the working principle and the performance of the CAPS, a trial system was established in the course of two years at a cost of about 20 million dollars. The trial constellation consists of two GEO satellites located at E87.5° and E110.5°, two DGEOs located at E130° and E142°, as well as barometric altimetry as a virtual satellite. Static and dynamic performance tests were completed for the Eastern, the Western, the Northern, the Southern and the Middle regions of China. The evaluation results are as follows： （1） land static test, plane accuracy range： C/A code, 15-25 m; P code, 5-10 meters; altitude accuracy range, 1- m; （2） land dynamic test, plane accuracy range, C/A code, 15-25 m; P code, 8-10m; （3） velocity accuracy, C/A code, 0.13-0.3 m s-1, P code, 0.15-0.17 m s- 1; （4） timing accuracy, C/A code, 160 ns, P code, 13 ns; （5） timing compared accuracy of Two Way Satellite Time and Frequency Transfer （TWSTFT）, average accuracy, 0.068 ns; （6） random error of the satellite ranging, 10.7 mm; （7） orbit determination accuracy, better than 2 m. The above stated random error is 1σ error. At present, this system is used as a preliminary operational system and a complete system with 3 GEO, 3 DGEO and 3 IGSO is being established.

Lung epithelial cell-derived IL-25 negatively regulates LPS-induced exosome release from macrophages

Background: Acute lung injury(ALI) is a major component of multiple organ dysfunction syndrome(MODS) following pulmonary and systemic infection. Alveolar macrophages(AMφ) are at the center of ALI pathogenesis. Emerging evidence has shown that cell-cell interactions in the lungs play an important regulatory role in the development of acute lung inflammation. However, the underneath mechanisms remain poorly addressed. In this study, we explore a novel function of lung epithelial cells(LEPCs) in regulating the release of exosomes from AMφ following LPS stimulation.Methods: For the in vivo experiments, C57 BL/6 wildtype(WT) mice were treated with lipopolysaccharide(LPS)(2 mg/kg) in 0.2 ml of saline via intratracheal aerosol administration. Bronchoalveolar lavage fluid was collected at 0–24 h after LPS treatment, and exosomes derived from AMφ were measured. For the in vitro studies, LEPCs and bone marrowderived Mφ(BMDM) were isolated from WT or TLR4-/-mice and were then cocultured in the Transwell? system. After coculture for 0–24 h, the BMDM and supernatant were harvested for the measurement of exosomes and cytokines.Results: We demonstrate that LPS induces macrophages(Mφ) to release exosomes, which are then internalized by neighboring Mφ to promote TNF-α expression. The secreted interleukin(IL)-25 from LEPCs downregulates Rab27 a and Rab27 b expression in Mφ, resulting in suppressed exosome release and thereby attenuating exosome-induced TNF-α expression and secretion.Conclusion: These findings reveal a previously unidentified crosstalk pathway between LEPCs and Mφ that negatively regulates the inflammatory responses of Mφ to LPS. Modulating IL-25 signaling and targeting exosome release may present a new therapeutic strategy for the treatment of ALI.

Electroacupuncture at Dazhui(GV14) and Mingmen(GV4) protects against spinal cord injury:the role of the Wnt/β-catenin signaling pathway

Electroacupuncture at Dazhui（GV14） and Mingmen（GV4） on the Governor Vessel has been shown to exhibit curative effects on spinal cord injury; however, the underlying mechanism remains poorly understood. In this study, we established rat models of spinal cord injury using a modified Allen＇s weight-drop method. Ninety-nine male Sprague-Dawley rats were randomly divided into three equal groups： sham（only laminectomy）, SCI（induction of spinal cord injury at T10）, and EA（induction of spinal cord injury at T10 and electroacupuncture intervention at GV14 and GV4 for 20 minutes once a day）. Rats in the SCI and EA groups were further randomly divided into the following subgroups： 1-day（n = 11）, 7-day（n = 11）, and 14-day（n = 11）. At 1, 7, and 14 days after electroacupuncture treatment, the Basso, Beattie and Bresnahan locomotor rating scale showed obvious improvement in rat hind limb locomotor function, hematoxylin-eosin staining showed that the histological change of injured spinal cord tissue was obviously alleviated, and immunohistochemistry and western blot analysis showed that Wnt1, Wnt3 a, β-catenin immunoreactivity and protein expression in the injured spinal cord tissue were greatly increased compared with the sham and SCI groups. These findings suggest that electroacupuncture at GV14 and GV4 upregulates Wnt1, Wnt3 a, and β-catenin expression in the Wnt/β-catenin signaling pathway, exhibiting neuroprotective effects against spinal cord injury.

Krüppel-like factor 7 attenuates hippocampal neuronal injury after traumatic brain injury

Our previous study has shown that the transcription factor Krüppel-like factor 7(KLF7) promotes peripheral nerve regeneration and motor function recovery after spinal cord injury.KLF7 also participates in traumatic brain injury,but its regulatory mechanisms remain poorly understood.In the present study,an HT22 cell model of traumatic brain injury was established by stretch injury and oxygenglucose deprivation.These cells were then transfected with an adeno-associated virus carrying KLF7(AAV-KLF7).The results revealed that,after stretch injury and oxygen-glucose deprivation,KLF7 greatly reduced apoptosis,activated caspase-3 and lactate dehydrogenase,downregulated the expression of the apoptotic markers B-cell lymphoma 2(Bcl-2)-associated X protein(Bax) and cleaved caspase-3,and increased the expression of βIII-tubulin and the antiapoptotic marker Bcl-2.Furthermore,KLF7 overexpression upregulated Janus kinase 2(JAK2) and signal transducer and activator of transcription 3(STAT3) phosphorylation in HT22 cells treated by stretch injury and oxygenglucose deprivation.Immunoprecipitation assays revealed that KLF7 directly participated in the phosphorylation of STAT3.In addition,treatment with AG490,a selective inhibitor of JAK2/STAT3,weakened the protective effects of KLF7.A mouse controlled cortical impact model of traumatic brain injury was then established.At 30 minutes before modeling,AAV-KLF7 was injected into the ipsilateral lateral ventricle.The protein and m RNA levels of KLF7 in the hippocampus were increased at 1 day after injury and recovered to normal levels at 3 days after injury.KLF7 reduced ipsilateral hippocampal atrophy,decreased the injured cortex volume,downregulated Bax and cleaved caspase-3 expression,and increased the number of 5-bromo-2'-deoxyuridine-positive neurons and Bcl-2 protein expression.Moreover,KLF7 transfection greatly enhanced the phosphorylation of JAK2 and STAT3 in the ipsilateral hippocampus.These results suggest that KLF7 may protect hippocampal neurons after traumatic brain injury through activation of the JAK2/STAT3 signaling pathway.The study was approved by the Institutional Review Board of Mudanjiang Medical University,China(approval No.mdjyxy-2018-0012) on March 6,2018.

Coercivity Ageing Effect on FePt Nanoparticles in Mesoporous Silica via Stepwise Synthesis Strategy

FePt nanoparticles in mesoporous silica are fabricated by a simple stepwise synthesis strategy.A pre-annealing temperature-dependent coercivity-ageing effect in FePt nanoparticles is observed at room temperature.For facecentered cubic（fcc）structured FePt nanoparticles,the ageing effect is sensitive to the pre-annealing temperature,especially when the temperature is close to the phase-transition.The special magnetic behavior of FePt nanoparticles reveals that the physical properties gradually change between fee and face-centered tetragonal structures,and will deepen our understanding of the mechanism of such magnetism in FePt nanoparticles.

Chx10+V2a interneurons in spinal motor regulation and spinal cord injury

Chx10-expressing V2 a(Chx10+V2 a) spinal interneurons play a large role in the excitatory drive of motoneurons. Chemogenetic ablation studies have demonstrated the essential nature of Chx10+V2 a interneurons in the regulation of locomotor initiation, maintenance, alternation, speed, and rhythmicity. The role of Chx10+V2 a interneurons in locomotion and autonomic nervous system regulation is thought to be robust, but their precise role in spinal motor regulation and spinal cord injury have not been fully explored. The present paper reviews the origin, characteristics, and functional roles of Chx10+V2 a interneurons with an emphasis on their involvement in the pathogenesis of spinal cord injury. The diverse functional properties of these cells have only been substantiated by and are due in large part to their integration in a variety of diverse spinal circuits. Chx10+V2 a interneurons play an integral role in conferring locomotion, which integrates various corticospinal, mechanosensory, and interneuron pathways. Moreover, accumulating evidence suggests that Chx10+V2 a interneurons also play an important role in rhythmic patterning maintenance, leftright alternation of central pattern generation, and locomotor pattern generation in higher order mammals, likely conferring complex locomotion. Consequently, the latest research has focused on postinjury transplantation and noninvasive stimulation of Chx10+V2 a interneurons as a therapeutic strategy, particularly in spinal cord injury. Finally, we review the latest preclinical study advances in laboratory derivation and stimulation/transplantation of these cells as a strategy for the treatment of spinal cord injury. The evidence supports that the Chx10+V2 a interneurons act as a new therapeutic target for spinal cord injury. Future optimization strategies should focus on the viability, maturity, and functional integration of Chx10+V2 a interneurons transplanted in spinal cord injury foci.

真空压力浸渗制备SiC_(p)/AZ91复合材料的显微组织、力学性能和磨损行为

采用真空压力浸透法制备SiC_(p)/AZ91复合材料,研究其显微组织、力学性能和耐磨性。结果表明,SiC颗粒均匀分布于金属基体中,并与基体界面结合良好。Mg_(17)Al_(12)相在SiC颗粒附近优先析出,SiC与AZ91基体的热膨胀系数失配导致高密度位错的产生,加速基体的时效析出。与AZ91合金相比,SiC颗粒的加入提高了复合材料的硬度和抗压强度,这主要是由于载荷传递强化和晶粒细化强化机制。此外,由于SiC具有优异的耐磨性,在磨损过程中形成稳定的支撑面保护基体。

挤压镁合金薄壁方管的耐撞性能（英文）

对不同长度的完整AZ31B镁合金薄壁方管和A6063铝合金薄壁方管以及具有诱导特征的薄壁管进行不同应变率的轴向压缩试验研究。研究发现,压缩过程中镁合金薄壁管局部屈曲,进而断裂,其中在断裂阶段出现3种耐撞性能断裂模式,分别是水平断裂、斜向断裂和螺旋断裂。相比于铝合金方管,镁合金薄壁管的吸能效果较差。在上述研究基础上,进一步分析长宽比、应变率和诱导特征对薄壁管耐撞性能的影响。结果表明,随着长宽比从1增加到4,镁合金薄壁管的最大压缩载荷和整体吸能比以幂函数的规律减小,而铝合金薄壁管则基本保持不变。随着压缩速率从5×10-5增加到10m/s,镁合金薄壁管的主要耐撞性能参数以指数形式增加,而铝合金薄壁管则变化很小。此外,本文作者引入的圆孔和缝的诱导特征未明显提高镁合金薄壁管的吸能效果,因此,后期需要在薄壁管不同位置设计更多种类和尺寸的诱导特征来提高镁合金薄壁管的吸能比。

金芪灌洗液对慢性鼻-鼻窦炎模型白兔鼻黏膜组织miRNA-155-3p表达的影响

目的探讨中药金芪灌洗液对慢性鼻-鼻窦炎(CRS)模型白兔鼻黏膜组织miRNA-155-3p表达的影响。方法从慢性鼻-鼻窦炎患者的鼻腔分泌物中单独分离出金黄色葡萄球菌菌株,培养后收集菌落并稀释至1.0×1011 cfu/L混悬液,通过手术方式移植到白兔的鼻腔内,复制慢性鼻-鼻窦炎动物模型。将实验白兔随机分为空白组、模型组、庆大霉素组、金芪灌洗液组,每组6只。各组白兔给予相应干预,观察2周后处死取材。采用实时荧光定量聚合酶链反应检测miRNA-155-3p的表达,HE染色观察各组鼻黏膜炎症及结构的变化。结果模型组、庆大霉素组miRNA-155-3p相对表达量较空白组升高(P<0.05),金芪灌洗液组较空白组降低(P<0.05),金芪灌洗液组miRNA-155-3p相对表达量较模型组降低(P<0.05),庆大霉素组较模型组升高(P<0.05),金芪灌洗液组miRNA-155-3p相对表达量较庆大霉素组降低(P<0.05)。白兔鼻窦黏膜形态学改变显示金芪灌洗液组黏膜形态趋于正常。结论金芪灌洗液可抑制miRNA-155-3p的表达,起到抗炎作用并修复白兔损伤的鼻黏膜。

Lymph node dissection in esophageal carcinoma: Minimally invasive esophagectomy vs open surgery

AIM: To compare lymph node dissection results of minimally invasive esophagectomy(MIE) and open surgery for esophageal squamous cell carcinoma.METHODS: We retrospectively reviewed data from patients who underwent MIE or open surgery for esophageal squamous cell carcinoma from January 2011 to September 2014. Number of lymph nodes resected, positive lymph node(p N+) rate, lymph node sampling(LNS) rate and lymph node metastatic(LNM) rate were evaluated. R E S U LT S : A m o n g 4 4 7 p a t i e n t s i n c l u d e d, 1 2 3 underwent MIE and 324 underwent open surgery. The number of lymph nodes resected did not significantly differ between the MIE and open surgery groups(21.1 ± 4.3 vs 20.4 ± 3.8, respectively, P = 0.0944). The p N+ rate of stage T3 esophageal squamous cell carcinoma in the open surgery group was higher than that in the MIE group(16.3% vs 11.4%, P = 0.031), but no differences was observed for stages T1 and T2 esophageal squamous cell carcinoma. The LNS rate at left para-recurrent laryngeal nerve(RLN) site was significantly higher for open surgery than for MIE(80.2% vs 43.9%, P < 0.001), but no differences were noted at other sites. The LNM rate at left para-RLN site in the open surgery group was significantly higher than that in the MIE group, regardless of pathologic T stage. CONCLUSION: For stages T1 and T2 esophageal squamous cell carcinoma, the lymph node dissection result after MIE was comparable to that achieved by open surgery. However, the efficacy of MIE in lymphadenectomy for stage T3 esophageal squamous cell carcinoma, particularly at left para-RLN site, remains to be improved.

Intravenous leiomyomatosis with different surgical approaches:Three case reports

BACKGROUND Intravenous leiomyomatosis(IVL) is a rare and complicated disease, which requires surgery by a multidisciplinary team. However, the optimal surgical approach has not been determined.CASE SUMMARY Here we report three cases of IVL treated with different surgical approaches. All patients presented with circulation symptoms. Two patients had lower extremity edema and the other had cardiopalmus. The diagnosis of IVL was confirmed based on the imagining examinations and pathological findings. All patients underwent surgical treatment and were discharged without any complications.CONCLUSION Preoperative examination is crucial for surgical planning and surgical approach is dependent on the patient's condition and tumor involvement.

基于倾向性评分匹配的输尿管外支架管和双J管在无管化经皮肾镜取石术中的疗效比较

目的比较输尿管外支架管与双J管在无管化经皮肾镜取石术(PCNL)中应用的安全性及有效性。方法选择2016年1月-2018年2月由笔者主刀实施无管化PCNL的105例患者的临床资料,采用倾向性评分匹配法(PSM),选取输尿管外支架管组与双J管组各30例进行安全性及有效性比较,比较两组患者手术时间、术后住院时间、术后1 d结石清除率、术后3个月结石清除率、内支架管相关性不适、术后疼痛评分、镇痛药物的需求及术后并发症的发生率等指标的区别。结果 60例患者手术均一期顺利完成,两组术后住院时间、术后1 d结石清除率、术后3个月结石清除率、术后疼痛评分、镇痛药物的需求及术后并发症的发生率比较,差异均无统计学意义(P>0.05),两组的手术时间分别为(45.32±27.78)和(67.51±30.53)min、支架管相关性不适的发生率分别为0.0%和43.3%,差异有统计学意义(P <0.05)。结论无管化PCNL术后短暂留置输尿管外支架管是安全有效的,与双J管相比,并不增加术后相关并发症的风险,相反它可以减少手术时间,不需第二次内镜手术拔除内支架管,减少了内支架管相关性不适,改善了患者的就医体验,节约了医疗成本,有一定的临床应用价值,值得推广应用。

Progress of Animal Research on Electro-acupuncture Treatment for Depression

This paper summarized the Chinese literatures in the previous 5 years about the pre-clinical animal researches on the application of electro-acupuncture(EA) treatment for depression,searched in China National Knowledge Infrastructure(CNKI).The efficiency of EA treatment for depression and the mechanism of it were discussed,to shed light on new ideas and new fronts for the further research on depression in clinical or pre-clinical fields.

Preparation and properties of open-cell zinc foams as human bone substitute material

Foamed zinc was prepared by infiltration casting process.The mechanical properties and corrosion resistance of the samples were studied,and the feasibility of the foamed zinc as a bone implant material was discussed.All the compression stress-strain curves of open-cell zinc foams with various cell size(1-4 mm)and porosity(55%-67%)show three stages:elastic stage,plastic stage,and densification stage.The compression strength increases with decreasing density.The smooth stress-strain response indicates a progressively deformation of open-cell zinc foam.In addition,the cell wall or edge bending and fracture are the dominated mechanisms for failure of open cell zinc foam.The immersion test for determining the corrosion rate of open cell zinc foam was conducted in simulated body fluid.It was found that zinc foam with a small cell size and high porosity showed a higher corrosion rate.In addition,open-cell zinc foams can effectively induce Ca-P deposition in immersion tests,showing good bioactivity.Therefore,the open cell zinc foam prepared in this experiment has a good potential application as a human bone substitute material.

Toward accurate measurement of property-dependent galaxy clustering I.Comparison of the Vmax method and the“shuffled”method

Galaxy clustering provides insightful clues to our understanding of galaxy formation and evolution,as well as the universe.The redshift assignment for the random sample is one of the key steps to accurately measure galaxy clustering.In this paper,by virtue of the mock galaxy catalogs,we investigate the effect of two redshift assignment methods on the measurement of galaxy two-point correlation functions(hereafter 2 PCFs),the Vmax method and the"shuffled"method.We have found that the shuffled method significantly underestimates both of the projected 2 PCFs and the two-dimensional 2 PCFs in redshift space,while the Vmax method does not show any notable bias on the 2 PCFs for volume-limited samples.For fluxlimited samples,the bias produced by the Vmax method is less than half of the shuffled method on large scales.Therefore,we strongly recommend the Vmax method to assign redshifts to random samples in the future galaxy clustering analysis.

Effects of different anesthesia methods on immune function, oxidative stress and related cytokine levels in elderly lung cancer patients undergoing radical operation

Objective: To investigate the effect of different anesthesia methods on immune function, oxidative stress and related cytokines in elderly patients undergoing radical mastectomy. Methods: The 90 elderly patients who underwent radical surgery for lung cancer from March 2016 to March 2018 were randomly divided into two groups, 45 cases each. One group was given sevoflurane inhalation anesthesia (sevoflurane group), and the other group was given propofol anesthesia (propofol group). The immune function, oxidative stress and related cytokine levels in immediately before induction of anesthesia (T0), 1 hour of surgery (T1), 2 hours of surgery(T2) and 2 hours after surgery (T3) were compared between the two groups. Result: At T1, T2 and T3, the levels of CD3+, CD4+ and CD4+/CD8+ in the two groups were significantly lower, and the levels of CD8+ were significantly higher those in T0 (P<0.05), and the levels of CD3+, CD4+ and CD4+/CD8+ in the sevoflurane group were significantly lower ,the level of CD8+ was significantly higher than those in the propofol group (P<0.05). There was no significant difference in VEGF and COX-2 levels between propofol groups at each time point (P>0.05), but at T3, VEGF and COX-2 levels in sevoflurane group were (415.12±60.23) pg/mL and (23.14±2.19) ng/mL respectively, which were significantly lower than those in T0 (P<0.05), and significantly lower than propofol group (P<0.05). There was no significant difference in MMP-2 and MMP-9 levels between propofol groups at each time point (P>0.05). The levels of MMP-2 and MMP-9 in the sevoflurane group at T2 and T3 were (324.83±26.81) ng/L, (352.05±31.96) ng/L, (313.19±27.32) ng/L and (345.21±33.04) ng/L respectively, which were significantly lower than those in T0, and significantly lower than propofol group (P<0.05). At T1 and T2, the MDA levels of the two groups were significantly higher than those in T0, and the SOD were significantly lower than those in T0 (P<0.05). At T2, the MDA level in the sevoflurane group was significantly lower than that in the propofol group (P<0.05), and the SOD level was significantly higher than that in the propofol group (P<0.05). Conclusion:Propofol intravenous anesthesia can protect the immune function of elderly patients undergoing radical lung cancer surgery, but sevoflurane can weaken the oxidative stress response and inhibit the expression of VEGF, COX-2, MMP-2 and MMP-9.

Effects of dezocine on cardiovascular response, stress response and cellular immune function before anesthesia induction in radical mastectomy for breast cancer

Objective: To investigate the effects of dezocine on cardiovascular response, stress response and cellular immune function before anesthesia induction in radical mastectomy for breast cancer. Methods: From January 2014 to January 2018, 220 patients with breast cancer undergoing modified radical mastectomy were randomly divided into observation group (110 cases) and control group (110 cases). The observation group was given dezocine before induction of anesthesia, while the control group was given the same amount of Sodium Chloride Injection. Heart rate (HR), mean arterial pressure (MAP), blood oxygen saturation (SpO2), aldosterone (ALD), renin (REN), cortisol (Cor), angiotensin Ⅱ (Ang-Ⅱ) and the level of T cell subsets at 5 time points before anesthesia (T1), 2 h after operation (T2), 10 hours (T3), 24 h (T4) and 48 h (T5) after operation were compared between the two groups. Results:There was no significant difference in HR and MAP between the two groups before anesthesia (30 min). HR and MAP of the two groups were higher at 2 h after operation and 10 h after operation than before, and the HR and MAP of the control group were higher than those of the observation group. There was no significant difference in ALD, REN, Cor and Ang-Ⅱ between the two groups at 30 min before anesthesia and 48 h after operation. ALD, REN, Cor and Ang-Ⅱ in the two groups at 2 h after operation and 10 h, 24 h after operation were higher than those at the 30 min before anesthesia, and ALD, REN, Cor and Ang-Ⅱ in the control group were higher than those in the observation group. There was no significant difference in CD3+, CD4+, CD4+/ CD8+ between the two groups at 30 min before anesthesia and 48 h after operation. CD3+, CD4+, CD4+/CD8+ in the two groups at 2 h after operation and 10 h, 24 h after operation were lower than those at the 30 min before anesthesia, and CD3+, CD4+, CD4+/CD8+ in the control group were lower than those in the observation group. Conclusion: Dezocine before anesthesia induction in radical mastectomy can effectively reduce cardiovascular response and stress response, and play a protective role in cellular immune function.

Development and global validation of a 1-week-old piglet head finite element model for impact simulations

Purpose:Child head injury under impact scenarios(e.g.falls,vehicle crashes,etc.)is an important topic in the field of injury biomechanics.The head of piglet was commonly used as the surrogate to investigate the biomechanical response and mechanisms of pediatric head injuries because of the similar cellular structures and material properties.However,up to date,piglet head models with accurate geometry and material properties,which have been validated by impact experiments,are seldom.We aim to develop such a model for future research.Methods:In this study,first,the detailed anatomical structures of the piglet head,including the skull,suture,brain,pia mater,dura mater,cerebrospinal fluid,scalp and soft tissue,were constructed based on CT scans.Then,a structured butterfly method was adopted to mesh the complex geometries of the piglet head to generate high-quality elements and each component was assigned corresponding constitutive material models.Finally,the guided drop tower tests were conducted and the force-time histories were ectracted to validate the piglet head finite element model.Results:Simulations were conducted on the developed finite element model under impact conditions and the simulation results were compared with the experimental data from the guided drop tower tests and the published literature.The average peak force and duration of the guide drop tower test were similar to that of the simulation,with an error below 10%.The inaccuracy was below 20%.The average peak force and duration reported in the literature were comparable to those of the simulation,with the exception of the duration for an impact energy of 11 J.The results showed that the model was capable to capture the response of the pig head.Conclusion:This study can provide an effective tool for investigating child head injury mechanisms and protection strategies under impact loading conditions.

Clinical Research of Pulmonary Langerhans Cell Histiocytosis in Children

Background： Pulmonary Langerhans cell histiocytosis （PLCH） is an interstitial primary pulmonary disease, characterized by Langerhans cell proliferation. It is easily misdiagnosed in children. This study aimed to characterize the clinical manifestations and features of PLCH by retrospective analysis. Meihods： A retrospective analysis was performed in 117 PLCH patients out of 338 LCH patients who were admitted in our center from November 2006 to October 2013. Variables between two groups were compared by Mann-Whitney U-test and Chi-square test. Kaplan-Meier curves were constructed to compare the survival rates and Cox regression to evaluate the effect of risk factors. Results： The median age of PLCH group was significantly lower than that ofnon-PkCH group （ 18.63 months vs. 43.4 months, P 〈 0.001 ）. All PLCH children had other organ involvement and only 11 cases （9.4%） had respiratory symptoms. The most common radiologic finding was cystic lesions （29 cases, 24.8%）. Pulmonary thnction abnormalities were dominated by obstructive ventilatory dysfunction （63 cases, 82.9%）. The 5-year overall survival （OS） of PECH children was 93.6% ± 2.3% and the event-free survival （EFS） was 55.7% ± 5.2%. Among the 38 cases with progressed or relapsed disease, five cases （13.2%） were due to progression or recurrence of lung damage. The 5-year OS of PECH children with ＂risk organ＂ involvement was significantly lower than those without ＂risk organ＂ involvement （86.0% ± 4.9% vs. 100%,X^2 = 8.793, P= 0.003）. The difference of EFS between two groups was also significant （43.7% ± 7.7% vs. 66.3% ± 6.5%,X^2 = 5.399, P = 0.020）. The ＂＇risk organ＂ involvement had a significant impact on survival （hazard ratio = 1.9, P = 0.039）. Conclusions： PLCH mainly occurs in young children, and only a small percentage of patients have respiratory symptoms. They generally have other organ involvement. Most of PLCH children have a good prognosis and most lung lesions could have improved or stabilized. Management of＂risk organ＂ involvement is the key point to improving EFS.

Rational design of ZnCdS/TpPa-1-COF heterostructure photocatalyst by strengthening the interface connection in solar hydrogen production reactions

ZnCdS quantum dots(QDs)are highly coveted in photocatalysis research for their exceptional visible-light responses and high light-absorption coefficients.However,their practical application is hindered by their tendency to aggregate,due to having high surface energies.To address this issue,herein,a heterostructure is synthesized by growing ZnCdS QDs with a size of approximately 5 nm onto the surface of a two-dimensional(2D)covalent organic framework(COF),TpPa-1-COF.This approach suppresses the aggregation of the QDs and improves their stability.The ZnCdS/TpPa-1-COF composite exhibited a peak hydrogen evolution rate of 6244.16μmol·g^(-1)·h^(-1),which was 2.89 and 4.18 times greater than that of ZnCdS and TpPa-1-COF,respectively.The zero-dimensional/two-dimensional(0D/2D)heterojunction formed by ZnCdS and TpPa-1-COF generates a strong interfacial force,which is attributed to the intimate contact between the interfaces.Tight connections accelerate charge separation,improve the utilisation of reduced electrons,and reduce the extent of agglomeration of the ZnCdS QDs,thereby resulting in high hydrogen production activity of the composites.Meanwhile,the photocatalytic mechanism is studied using Kelvin probe force microscopy and theoretical calculations.This study offers a novel approach for creating sulfide photocatalysts and is crucial for investigating the potential practical applications of the related photocatalysts.