海藻酸钙水凝胶喷射式生物3D打印工艺研究

提出一种利用平行排列的双排压电喷嘴喷射海藻酸钠和氯化钙两种组分的溶液进行大尺寸水凝胶支架制造的方法,研究了不同溶液组分与打印工艺参数对流变特性与喷射性能的关系。研究表明:适合双组分喷墨打印的最佳溶液质量浓度为40 g/L,最佳打印工艺参数组合为电压幅值80~100 V、打印频率0.2~5 kHz。在此参数下完成了尺寸60 mm×30 mm×1 mm海藻酸钙凝胶支架的打印。该打印方法工艺简单、效率高、材料利用率高,有望应用于结构复杂的组织工程支架的一体化制造中。

皮肤修复生物3D打印的研究进展与挑战

皮肤作为人体最大的器官,有着屏障功能、免疫应答、防止水分流失和排泄废物等重要作用。大面积的严重皮肤损伤患者会由于缺乏充足的可移植皮肤而死亡。生物3D打印技术的发展为可移植皮肤的制造提供了解决办法。生物3D打印技术可以定制化制造功能性的皮肤替代品,有望解决移植皮肤短缺的困难。本文简述了皮肤创伤修复原理,比较了用于皮肤修复的生物材料墨水、细胞和主要的生物3D打印技术,分析了光电技术在3D打印皮肤上的应用潜力,并总结了生物3D打印技术在皮肤修复应用中所面临的挑战和未来的发展方向,提出了光电技术在生物3D打印中的应用需求。

现代土壤磁化率空间分布特征及成壤影响因素分析——以桑干河阳原段为例

为了揭示影响成壤作用发生的主要因素,对河北省阳原县桑干河流域表层土壤开展常规土壤指标和环境磁学参数的地统计学分析,结果表明,土壤的频率磁化率(χfd20)、Eh值、有机质、黏土-粉砂含量等参数的空间分布特征受控于研究区的高程,而土壤的含水量、铁游离度和活化度的空间分布特征受控于坡向。因此,在影响成壤作用的五大因素(母质、气候、地形、有机质、时间)中,地形(高程、坡向)是影响研究区成壤作用强弱的主要因素。此外,虽然前人发现频率磁化率和铁游离度都能反映铁氧化物含量和成壤作用强弱,但本次研究通过对比空间分布特征发现,频率磁化率与有机质、Eh值等土壤指标有较好的相似性,且与耕地类型分布一致,所以,相对于铁游离度,频率磁化率更能反映研究区土壤发育状况。

高速列车降噪涂料涂抹仿真研究

为降低高速列车车厢内的噪声,提高乘坐舒适度,设计一种在车厢底板铝型材内腔涂抹阻尼浆的装置。利用FLUENT软件模拟涂料在该涂抹装置关键部件挤压结构内的流动,得到挤压结构内部速度场和压力场的分布特征,并对比不同入口速度和涂料黏度下的压力场和速度场。研究结果表明:涂料在挤压结构内部流动顺畅,出口处涂料分布均匀。发现入口速度对挤压结构内部压力场和速度场均有较大影响,涂料黏度对挤压结构内部压力场有较大影响,对速度场影响很小。研究结果为涂料涂抹装置改进和膏体材料变截面挤压实验提供参考。

Episcleral macular buckling for posterior retinal detachment in silicone oil filled eyes associated with myopic macular hole

AIM: To evaluate anatomical and visual outcomes of episcleral macular buckling (EMB) for posterior retinal detachment in silicone oil filled eyes associated with myopic macular hole.METHODS: Five cases of EMB for initial failure of retinal reattachment after internal limiting membrane (ILM) peeling and silicone oil tamponade caused by myopic macular hole were retrospectively reviewed. A silicone sponge sutured directly across the macular region was performed on the silicone oil filled eyes. Silicone oil was removed no sooner than 1 month post- EMB. The duration of follow -up time after removal of silicone oil was more than 3 months.RESULTS: Retinas of five eyes were all reattached at the last follow-up. The postoperative vision ranged from counting fingers to 0.08.CONCLUSION: Anatomical results improved after EBM for posterior retinal detachment in silicone oil filled eyes associated with myopic macular hole, which was not evident for visual outcome.

Million-year-old groundwater revealed by krypton-81 dating in Guanzhong Basin,China

Groundwater age,defined as the mean subsurface residence time spent isolated from the atmosphere,is of crucial significance for managing water resources and industrial waste.It is also very useful for understanding subsurface contaminant transport,and for paleoclimate reconstruction.It is an important parameter

Clinical epidemiology and disease burden of bronchiolitis in hospitalized children in China:a national cross-sectional study

Background Bronchiolitis is a common acute lower respiratory tract infection(ALRTI)and the most frequent cause of hospitalization of infants and young children with ALRTI.Respiratory syncytial virus is the main pathogen that leads to severe bronchiolitis.The disease burden is relatively high.To date,few descriptions of the clinical epidemiology and disease burden of children hospitalized for bronchiolitis are available.This study reports the general clinical epidemiological characteristics and disease burden of bronchiolitis in hospitalized children in China.Methods This study included the face sheet of discharge medical records collected from 27 tertiary children’s hospitals from January 2016 to December 2020 that were aggregated into the FUTang Update medical REcords(FUTURE)database.The sociodemographic variables,length of stay(LOS)and disease burden of children with bronchiolitis were analyzed and compared using appropriate statistical tests.Results In total,42,928 children aged 0–3 years were hospitalized due to bronchiolitis from January 2016 to December 2020,accounting for 1.5%of the total number of hospitalized children of the same age in the database during the period and 5.31%of the hospitalizations for ALRTI.The male to female ratio was 2.01:1.Meanwhile,more boys than girls were observed in different regions,age groups,years,and residences.The 1–2 year age group had the greatest number of hospitalizations for bronchiolitis,while the 29 days–6 months group had the largest proportion of the total inpatients and inpatients with ALRTI in the same age group.In terms of region,the hospitalization rate of bronchiolitis was the highest in East China.Overall,the number of hospitalizations from 2017 to 2020 showed a decreasing trend from that in 2016.Seasonally,the peak hospitalizations for bronchiolitis occurred in winter.Hospitalization rates in North China in autumn and winter were higher than those in South China,while hospitalization rates in South China were higher in spring and summer.Approximately,half of the patients with bronchiolitis had no complications.Among the complications,myocardial injury,abnormal liver function and diarrhea were more common.The median LOS was 6 days[interquartile range(IQR)=5–8],and the median hospitalization cost was 758 United States dollars(IQR=601.96–1029.53).Conclusions Bronchiolitis is a common respiratory disease in infants and young children in China,and it accounts for a higher proportion of both total hospitalizations and hospitalizations due to ALRTI in children.Among them,children aged 29 days–2 years are the main hospitalized population,and the hospitalization rate of boys is significantly higher than that of girls.The peak season for bronchiolitis is winter.Bronchiolitis causes few complications and has a low mortality rate,but the burden of this disease is heavy.

Superior single-mode lasing in a self-assembly CsPbX3 microcavity over an ultrawide pumping wavelength range

All-inorganic perovskite micro/nanolasers are emerging as a class of miniaturized coherent photonic sources for many potential applications,such as optical communication,computing,and imaging,owing to their ultracompact sizes,highly localized coherent output,and broadband wavelength tunability.However,to achieve singlemode laser emission in the microscale perovskite cavity is still challenging.Herein,we report unprecedented single-mode laser operations at room temperature in self-assembly Cs Pb X3 microcavities over an ultrawide pumping wavelength range of 400–2300 nm,covering one-to five-photon absorption processes.The superior frequency down-and upconversion single-mode lasing manifests high multiphoton absorption efficiency and excellent optical gain from the electron–hole plasma state in the perovskite microcavities.Through direct compositional modulation,the wavelength of a single-mode Cs Pb X3 microlaser can be continuously tuned from blue-violet to green(427–543 nm).The laser emission remains stable and robust after long-term high-intensity excitation for over 12 h(up to 4.3×107 excitation cycles)in the ambient atmosphere.Moreover,the pump-wavelength dependence of the threshold,as well as the detailed lasing dynamics such as the gain-switching and electron–hole plasma mechanisms,are systematically investigated to shed insight into the more fundamental issues of the lasing processes in Cs Pb X3 perovskite microcavities.

Autophagy induced by human adenovirus B7 structural protein VI inhibits viral replication

Human adenovirus B7(HAdV-B7)causes severe acute lower respiratory tract infections in children.However,neither the child-specific antivirals or vaccines are available,nor the pathogenesis is clear.Autophagy,as part of innate immunity,plays an important role in resistance to viral infection by degrading the virus and promoting the development of innate and adaptive immunity.This study provided evidence that HAdV-B7 infection induced complete autophagic flux,and the pharmacological induction of autophagy decreased HAdV-B7 replication.In this process,the host protein Bcl2-associated athanogene 3(BAG3)mediated autophagy to inhibit the replication of HAdV-B7 by binding to the PPSY structural domain of viral protein pVI through its WW structural domain.These findings further our understanding of the host immune response during viral infection and will help to develop broad anti-HAdV therapies.

Clinical epidemiology and disease burden of adenoviral encephalitis in hospitalized children in China:A nationwide cross-sectional study

Importance:Adenovirus encephalitis is a significant infectious disease of the central nervous system that commonly affects children under the age of 5 and has a profound impact on the health of infants and young children throughout China.National multicenter epidemiological studies have significant public health implications.Objective:This study aims to report the epidemiology of adenovirus encephalitis in hospitalized children in China,providing valuable guidance for clinicians.Methods:The data utilized in this study were extracted from the comprehensive Futang Update Medical Records database,which comprises discharge medical records collected by 27 tertiary children’s hospitals between January 2016 and December 2018 in China.Specifically,the face sheet of discharge medical records encompassed critical sociodemographic variables and basic medical care details.Results:In this database,a total of 544 children were hospitalized due to adenoviral encephalitis.The male-to-female ratio was 1.62:1,with more boys being affected across different age groups and places of residence.Of the children hospitalized,the highest number of hospitalizations occurred in the 1–3-year age group and the number of hospitalizations decreased each year from 2016 to 2018.The disease exhibits seasonal characteristics with a pronounced peak in the summer months of June and July.While most children(58%)did not have any significant complications,one-third of them developed respiratory complications,including pneumonia and acute bronchitis.The median length of stay for adenoviral encephalitis was 7 days,and the median cost of hospitalization was 2145.56 US dollars.Interpretation:This study highlights the prevalence of adenovirus encephalitis in hospitalized children in China.Children aged 1–3 years were found to be the main demographic hospitalized due to this condition,with boys being significantly more affected than girls.The seasonal variations of adenovirus encephalitis were also found to be significant.Fortunately,the fatality rate associated with this condition was low,and the prognosis was generally favorable.