Development of a simulator for training of fetoscopic myelomeningocele surgery

Objective

To develop a realistic simulation model for laparotomy-assisted fetoscopic spina bifida aperta (SBa) surgery, to be used for training purposes and preoperative planning.

Methods

The predefined general requirement was a realistic model of an exteriorized uterus, allowing all neurosurgical steps of the intervention. The uterus was modelled using ultrasound and MRI images of a 25 weeks’ gravid uterus, consisting of flexible polyurethane foam coated with pigmented silicone. The fetal model, contained an opening on the dorsal side for a customizable spinal insert with all the aspects of a SBa, including a cele, placode, and myofascial and skin layer. The model was assessed in a series of validation experiments.

Results

Production costs are low, uterus and fetus are reusable. Placental localization and the level and size of the spinal defect are adjustable, enabling case-specific adaptations. All aspects of the simulator were scored close to realistic or higher for both appearance and functional capacities.

Conclusions

This innovative model provides an excellent training opportunity for centers that are starting a fetoscopic SBa repair program. It is the first simulation model with adjustable spinal defect and placental localisation. Further objective validation is required, but the potential for using this model in preoperative planning is promising.     

Realizing stable operation of anaerobic ammonia oxidation at low temperatures treating low strength synthetic wastewater

The low activity of Anammox bacteria at low temperatures and competition from nitrite oxidation bacteria(NOB) when treating low strength wastewater have been major bottlenecks in implementing Anammox in mainstream wastewater treatment. By intermittent high strength feeding(IHSF) and stepwise temperature reduction, stable operation of a granular Anammox reactor was realized at low temperatures(down to 15°C) for 28 days when treating low strength synthetic wastewater. The nitrogen loading rate reached 1.23–1.34 kgN/m~3/day,and the total nitrogen removal rate reached 0.71–0.98 kgN/m~3/day. The IHSF enriched the Anammox sludge in high strength cycles and compensated for sludge loss in low strength cycles, and the high concentration of ammonium in high strength cycles inhibited NOB. The 16 SrRNA gene sequencing results revealed that Candidatus Kuenenia was predominant in the reactor at low temperatures.     

强还原与生物炭对土壤酶活性和温室气体排放的影响

本研究设置未修复对照（CK）、土壤强还原处理（RSD）、生物炭修复（BC）以及RSD与生物炭联合修复（RSD+BC）,采用培养实验对比研究不同修复处理对设施蔬菜地土壤酶活性和温室气体（CO₂和N₂O）排放的影响.结果表明：相比CK,RSD和RSD+BC处理显著提高了β-葡萄糖苷酶（βG）、纤维二糖水解酶（CBH）、过氧化物酶（PEO）、β-N-乙酰氨基葡萄糖苷酶（NAG）和酸性磷酸酶（AP）的活性以及酶C：P与酶N：P值（P<0.05）,而BC处理对上述5种胞外酶活性的影响并不显著.同CK相比,RSD、BC和RSD+BC处理的CO₂排放量分别提高了10.6、1.1和12.2倍;RSD处理的N₂O排放量亦显著增加,但BC和RSD+BC处理的则显著降低（P<0.05）.与RSD相比,RSD+BC处理的N₂O排放量和综合温室效应（GWP）显著减少了86.9%和37.8%.结构方程模型分析表明：βG与土壤可溶性有机碳（DOC）对CO₂累积排放量具有直接正效应,且βG与CBH通过影响DOC含量间接影响CO₂排放;NO₃^--N和NH₄⁺-N对N₂O累积排放量具有直接显著负效应.综合考虑土壤酶活性和温室气体减排,RSD+BC联合修复效果更佳.     

近30a来乐清湾海岸线与海岸湿地变迁分析

以Landsat ETM/ TM影像为主要数据源,采用人机交互的方式提取了1990~2017年间6期乐清湾海岸线。利用马尔科夫矩阵法计算了滩涂转化规律,并按照年份进行岸线和海岸湿地变迁分析。结合当地相关资料,开展了乐清湾区域海岸线和海岸湿地变化的驱动力分析。结果表明:乐清湾岸线以人工岸线为主,岸线变化剧烈,变化速率分布不均,海岸湿地的变化整体面积变化不大,其中人工湿地主要由自然滩涂湿地转化而来,人类围填是乐清湾海岸线和海岸湿地变迁的主要因素。     

灾害损失等级划分的模糊灾度判别法

作者应用模糊模式识别理论于灾害损失等级划分的研究，提出了模糊灾度概念，并建立了模糊灾度等级的隶属函数，从而给出了一种可用于灾害损失等级划分的模糊灾度判别法。     

Renewable Energy Legislation in China:Politicaland Institutional Strategy for EffectiveImplementation

Over the past decade, the Chinese government has developed several plans regulations and policy measures related to the development of renewable energy technologies and has implemented a series of pilot projects. Chinese policymakers have spent several years studying how renewable energy policy models that have been used internationally could be implemented in China. Programs are currently underway to implement pilot renewable portfolio standards, or mandatory market shares (MMS) for renewable energy, in several provinces. This paper examines the primary institutions that are involved in promoting renewable policies in China, the structure of the policies that currently are being drafted, and the status of the complementary, national-level renewable energy law being drafted to provide a legal basis for ongoing local and national-level policies. It then examines the legal requirements for promoting renewable energy legislation under the Chinese law-making system. Finally, it provides recommendations for     

基于WRFDA-Chem的中国大气成分数据再分析方法研究

大气成分数据是开展空气质量预报、认识大气污染形成机理、评估空气污染各种效应的基础,而融合了模式结果和观测资料的大气成分再分析数据则有更广泛的应用价值.本文基于WRFDA-Chem空气质量模型和三维变分同化技术,逐时同化地面站点污染物浓度观测资料 （包括PM_2.5、PM₁₀、O₃、SO₂、NO₂及CO）,建立了大气成分数据再分析的方法.以2019年7月和12月为例,构建空间分辨率为10 km、时间分辨率为1 h的全国大气成分再分析数据,并对该方法的性能进行了检验.结果表明,经过再分析后的大气成分数据的时间变化趋势和空间分布得到显著改善,其中,7月PM_2.5 和O₃的平均偏差分别降低了55%和39%,相关系数分别提升了77%和7%,达到0.80和0.98;12月PM_2.5 和O₃的平均偏差分别降低了55%和68%,相关系数分别提升了58%和13%,达到0.98和0.98.综合而言,基于WRFDA-Chem逐小时同化全国站点空气质量监测资料,能够得到高时空分辨率的大气成分再分析数据,可以为认识我国大气污染的演变特征和制定科学的管控措施提供有效支撑.     

Characteristics of ambient volatile organic compounds during spring O3 pollution episode in Chengdu, China

Surface ozone (O₃) has become a critical pollutant impeding air quality improvement in many Chinese megacities. Chengdu is a megacity located in Sichuan Basin in southwest China, where O₃ pollution occurs frequently in both spring and summer. In order to understand the elevated O₃ during spring in Chengdu, we conducted sampling campaign at three sites during O₃ pollution episodes in April. Volatile organic compounds (VOCs) compositions at each site were similar, and oxygenated VOCs (OVOCs) concentrations accounted for the highest proportion (35%-45%), followed by alkanes, alkens (including acetylene), halohydrocarbons, and aromatics. The sensitivity of O₃ to its precursors was analyzed using an observation based box model. The relative incremental reactivity of OVOCs was larger than other precursors, suggesting that they also played the dominant role in O₃ formation. Furthermore, the positive matrix factorization model was used to identify the dominant emission sources and to evaluate their contribution to VOCs in the city. The main sources of VOCs in spring were from combustion (27.75%), industrial manufacturing (24.17%), vehicle exhaust (20.35%), and solvent utilization (18.35%). Discussions on VOCs and NO_x reduction schemes suggested that Chengdu was typical in the VOC-limited regime, and VOC emission reduction would help to prevent and control O₃. The analysis of emission reduction scenarios based on VOCs sources showed that the emission reduction ratio of VOCs to NO₂ needs to reach more than 3 in order to achieve O₃ prevention. Emission reduction from vehicular exhaust source and solvent utilization source may be more effective.     

钯基催化剂电催化氢解处理氯代有机物的研究进展

氯代有机物(COPs)是一类重要的化工生产原料和中间体,但其高持久性、高生物累积性、致癌性及遗传毒性将对生态环境和人体健康造成巨大危害. 开发消除COPs毒性的新型技术,实现人与自然和谐共生,成为国际学术界和工业界共同关注的焦点. 电催化氢解技术(ECH)因具有高反应活性、结构简单、二次污染风险小等优势而备受青睐. 本文系统综述了钯(Pd)基催化剂上的ECH反应机制,探究强还原性氢自由基(H*)的定量分析方法,揭示脱氯反应与析氢副反应间的竞争关系. 通过分析H*产量、污染物脱附、电场等因素对脱氯速率的影响规律,建立晶面与效能间构效关系,识别不同反应条件下制约ECH速率的因素. 聚焦阴极催化活性低、易受脱氯产物毒化的关键问题,通过暴露Pd活性中心位点、强化水裂解、调控电子效应和配体效应及几何效应等策略增强催化剂产H*量和抗毒化性能. 开展ECH脱氯反应路径识别、脱氯性能影响因素探讨以及生物安全性评价,并基于当前存在的关键科学问题,展望ECH技术的发展趋势,为设计和发展实用型环境催化新技术和新型催化材料指明方向.      

废液晶显示器偏光片水热产乳酸研究

以废液晶显示面板中的偏光片为原料,对其进行水热产乳酸研究,并考察了反应温度(250～375℃)、反应时间(1～11min)以及氧化剂(体积分数为30％的H2O2)投加量(0～1.0 mL)对乳酸产率的影响.结果表明,反应温度、反应时间均会对偏光片水热产乳酸产生一定影响,乳酸产率随反应温度和反应时间的增加呈现先增加后减少的趋势,最佳水热条件为反应温度350℃,反应时间5 min,此时乳酸产率达17％左右.投加氧化剂能显著提高乳酸的产率,在最佳水热条件下,氧化剂投加量为0.6 mL时乳酸的产率可提高到21％.