Fabrication and performance of PET mesh enhanced cellulose acetate membranes for forward osmosis

Polyethylene terephthalate mesh(PET) enhanced cellulose acetate membranes were fabricated via a phase inversion process. The membrane fabrication parameters that may affect the membrane performance were systematically evaluated including the concentration and temperature of the casting polymer solution and the temperature and time of the evaporation, coagulation and annealing processes. The water permeability and reverse salt flux were measured in forward osmosis(FO) mode for determination of the optimal membrane fabrication conditions. The optimal FO membrane shows a typical asymmetric sandwich structure with a mean thickness of about 148.2 μm. The performance of the optimal FO membrane was tested using 0.2 mol/L Na Cl as the feed solution and 1.5 mol/L glucose as the draw solution. The membrane displayed a water flux of 3.47 L/(m2·hr) and salt rejection of95.48% in FO mode. While in pressure retarded osmosis(PRO) mode, the water flux was4.74 L/(m2·hr) and salt rejection 96.03%. The high ratio of water flux in FO mode to that in PRO mode indicates that the fabricated membrane has a lower degree of internal concentration polarization than comparable membranes.     

Characteristics of atmospheric single particles during haze periods in a typical urban area of Beijing: A case study in October, 2014

To investigate the composition and possible sources of particles, especially during heavy haze pollution, a single particle aerosol mass spectrometer (SPAMS) was deployed to measure the changes of single particle species and sizes during October of 2014, in Beijing. A total of 2,871,431 particles with both positive and negative spectra were collected and characterized in combination with the adaptive resonance theory neural network algorithm (ART-2a). Eight types of particles were classified: dust particles (dust, 8.1%), elemental carbon (EC, 29.0%), organic carbon (OC, 18.0%), EC and OC combined particles (ECOC, 9.5%), Na-K containing particles (NaK, 7.9%), K-containing particles (K, 21.8%), organic nitrogen and potassium containing particles (KCN, 2.3%), and metal-containing particles (metal, 3.6%). Three haze pollution events (P1, P2, P3) and one clean period (clean) were analyzed, based on the mass and number concentration of PM_2.5 and the back trajectory results from the hybrid single particle Lagrangian integrated trajectory model (Hysplit-4 model). Results showed that EC, OC and K were the major components of single particles during the three haze pollution periods, which showed clearly increased ratios compared with those in the clean period. Results from the mixing state of secondary species of different types of particles showed that sulfate and nitrate were more readily mixed with carbon-containing particles during haze pollution episodes than in clean periods.     

上海市用水量与经济发展的关系研究

选取上海市1998～2006年的用水量、经济数据,通过人均GDP与人均用水量之间的关系,探索上海市用水量与经济发展是否存在环境库兹涅茨曲线关系,剖析上海市经济增长与用水量的演变规律,结果表明：上海市经济增长与用水量之间不符合一般的环境库兹涅茨曲线特征,重新建立了曲线模型,通过模型计量分析,人均总用水量,人均农业用水量,人均生活用水量与人均GDP曲线均为“U＋倒U”形,而人均工业用水量人均GDP曲线为“倒U＋U”形,为合理开发上海市水资源提供较为科学严谨的依据。     

模拟盐碱胁迫对小麦种子萌发的影响

农田土壤盐碱化已经成为影响小麦种子萌发的一个重要因素。利用NaCl和Na2CO3模拟盐碱胁迫对小麦种子的萌发影响实验表明：四种小麦的萌发率均表现出显著差异,并随着浓度的增加而表现出降低的趋势,并与无盐碱胁迫的萌发率表现相一致,其萌发率及萌发耐盐碱性次序高低顺序为：济南17〉淄麦12〉邯6172〉泰山9818。在单一盐或碱胁迫条件下,小麦的萌发率总是随着NaCl或Na2CO3浓度的增加而表现出不同程度的降低。无论以NaCl浓度增加为主还是以Na2CO3浓度增加为主的情况下,小麦种子的萌发均随着浓度的增加受到明显的抑制作用。盐碱复合胁迫对小麦种子萌发的影响机理还缺乏生物学及生理学上的解释,仍需要进行深入研究。     

Evaluation of the readsorption of plutonium and americium in dynamic fractionations of environmental solid samples

A dynamic extraction system exploiting sequential injection (SI) for sequential extractions incorporating a specially designed extraction column is developed to fractionate radionuclides in environmental solid samples such as soils and sediments. The extraction column can contain up to 5 g of a soil sample, and under optimal operational conditions it does not give rise to creation of back pressure. Attention has been placed on studies of the readsorption problems during sequential extraction using a modified Standards, Measurements and Testing (SM&T) scheme with four-step sequential extractions. The degree of readsorption in dynamic and conventional batch extraction systems is compared and evaluated by using a double-spiking technique. A high degree of readsorption of plutonium and americium (>75%) was observed in both systems, and they also exhibited similar distribution patterns of the two radionuclides. However, the dynamic system is fully automated, eliminates manual separations, significantly reduces the operational time required, and offers detailed kinetic information.     

Evolution characteristics and transcriptional responses to multiple stresses of NAC genes in Chenopodium quinoa and its ancestral diploid species北大核心CSCD

NAC是一类广泛参与调控植物在生物和非生物胁迫下防御应答的转录因子.基于系统的比较基因组学研究方法,对藜麦Chenopodium quinoa的NAC基因进行进化与多个生物和非生物逆境下的应答研究.在藜麦C.quinoa、祖先二倍体Chenopodium pallidicaule和Chenopodium suecicum基因组中分别共鉴定得到106、54和54个NAC基因.染色体定位数据表明藜麦基因组中18个NAC基因涉及串联倍增事件.3个物种NAC基因的系统进化树证明藜麦基因组中存在NAC基因的倍增与丢失.藜麦分别和C.pallidicaule和C.suecicum之间同源基因组模块的对应数目关系进一步证明藜麦保留了相当数量的祖先二倍体NAC基因,是其NAC基因倍增的主要动力.此外,藜麦NAC基因在干旱、高温、盐、低磷胁迫和GCFSV侵染下的表达模式被阐明;大量NAC基因被显著地诱导表达,推测其参与了藜麦在生物和非生物胁迫下的防御应答反应.本研究结果为藜麦的遗传育种提供了优良的候选NAC基因.(图7参26)     

Recovery and reuse of floc sludge for high-performance capacitors

• The feasibility of facile fabrication of capacitor from floc sludge is discussed. • The porous carbon composites are obtained by acidification and KOH activation. • The as-prepared 3D structure has large surface area and optimal pore size. • Admirable specific capacitance and outstanding cycling stability are obtained. In this paper, floc sludge was transformed into porous carbon matrix composites by acidification and KOH activation at high temperature and used as an electrode material for application in capacitors. The effects of different treatment processes on the electrochemical properties of sludge materials were compared. The results of electrochemical tests showed that the sludge electrode exhibited excellent energy storage performance after HNO₃ acidification and KOH activation with a mass ratio of 3:1 (KOH/C). The specific capacitance of the sludge electrode reached 287 F/g at a current density of 1 A/g. In addition, the sludge electrode material showed excellent cycle stability (specific capacity retained at 93.4% after 5000 cycles at 5 A/g). Based on XRD, FTIR, SEM, TEM, and BET surface analysis, the morphology of sludge electrode materials can be effectively regulated by chemical pretreatment. The best-performing material showed a 3D porous morphology with a large specific surface area (2588 m²/g) and optimal pore size distribution, improving ion channels and charge conductivity. According to the life cycle assessment of floc sludge utilization, it reduced the resource consumption and toxicity risk by more than 90% compared with ordinary sludge disposal processes. This work provided a cost-effective and eco-friendly sludge reuse method and demonstrated the application potential of sludge-based materials in high-performance supercapacitors.     

Partial anammox achieved in full scale biofilm process for typical domestic wastewater treatment

• A full scale biofilm process was developed for typical domestic wastewater treatment. • The HRT was 8 h and secondary sedimentation tank was omitted. • Candidatus Brocadia were enriched in the HBR with an abundance of 2.89%. • Anammox enabled a stable ammonium removal of ~15% in the anoxic zone. The slow initiation of anammox for treating typical domestic wastewater and the relatively high footprint of wastewater treatment infrastructures are major concerns for practical wastewater treatment systems. Herein, a 300 m³/d hybrid biofilm reactor (HBR) process was developed and operated with a short hydraulic retention time (HRT) of 8 h. The analysis of the bacterial community demonstrated that anammox were enriched in the anoxic zone of the HBR process. The percentage abundance of Candidatus Brocadia in the total bacterial community of the anoxic zone increased from 0 at Day 1 to 0.33% at Day 130 and then to 2.89% at Day 213. Based upon the activity of anammox bacteria, the removal of ammonia nitrogen (NH₄⁺-N) in the anoxic zone was approximately 15%. This showed that the nitrogen transformation pathway was enhanced in the HBR system through partial anammox process in the anoxic zone. The final effluent contained 12 mg/L chemical oxygen demand (COD), 0.662 mg/L NH₄⁺-N, 7.2 mg/L total nitrogen (TN), and 6 mg/L SS, indicating the effectiveness of the HBR process for treating real domestic wastewater.     

纳米银诱导细胞自噬的分子机制和生物效应

细胞自噬对维持细胞的生长代谢以及细胞内环境稳态具有重要意义。近年来,纳米银(silver nanoparticles, AgNPs)与细胞自噬的关系逐渐被揭示。深入了解AgNPs诱导的细胞自噬效应有助于其在医药领域的进一步应用,也能为全面评估AgNPs的纳米毒性提供科学依据。本文重点介绍AgNPs诱导细胞自噬的机制及其涉及的主要信号通路,通过探讨不同理化性质的AgNPs诱导自噬的不同结果及机制,归纳总结AgNPs诱导细胞自噬的生物效应,以期为全面认识AgNPs的自噬效应提供科学依据。     

Response to environmental flows in the Lower Tarim River, Xinjiang, China: an ecological interpretation of water-table dynamics

Increased water-dependent development and utilization have led to significant environmental and hydrological degradation of the Tarim River in western China and its dependent ecosystems. Between the 1950s and 1970s, 350 km of the lower reaches were drained and between 1960 and 1980 the water-table fell from between −2 and −3 m to between −8 and −10 m. Subsequently, riparian ecosystems were seriously degraded. In 2000, the Chinese government launched a program to restore the lower reaches of the river. Four environmental flows of 1034×10⁶ m³ were released from 2000 to 2002. This paper interprets and discusses the ecological significance of changes following the releases and identifies the relationship between water-table dynamics and vegetation responses. Short-term objectives for river restoration are proposed with possible monitoring parameters suggested.