Critical Risk Indicators (CRIs) for the electric power grid: a survey and discussion of interconnected effects

The electric power grid is a critical societal resource connecting multiple infrastructural domains such as agriculture, transportation, and manufacturing. The electrical grid as an infrastructure is shaped by human activity and public policy in terms of demand and supply requirements. Further, the grid is subject to changes and stresses due to diverse factors including solar weather, climate, hydrology, and ecology. The emerging interconnected and complex network dependencies make such interactions increasingly dynamic, posing novel risks, and presenting new challenges to manage the coupled human–natural system. This paper provides a survey of models and methods that seek to explore the significant interconnected impact of the electric power grid and interdependent domains. We also provide relevant critical risk indicators (CRIs) across diverse domains that may be used to assess risks to electric grid reliability, including climate, ecology, hydrology, finance, space weather, and agriculture. We discuss the convergence of indicators from individual domains to explore possible systemic risk, i.e., holistic risk arising from cross-domain interconnections. Further, we propose a compositional approach to risk assessment that incorporates diverse domain expertise and information, data science, and computer science to identify domain-specific CRIs and their union in systemic risk indicators. Our study provides an important first step towards data-driven analysis and predictive modeling of risks in interconnected human–natural systems.

     

Advances in the study of directed evolution for cellulases

If cellulose can be effectively hydrolyzed into glucose by cellulase, the production costs of hydrogen, ethanol or other chemicals from cellulosic materials will be greatly decreased, and economically viable production of biohydrogen and bioethanol will become feasible. Cellulose is degraded into glucoses by multi-component enzyme systems. Nowadays cellulases are widely used in brewing, food, bioenergy, fodder, textiles, paper, pharmaceuticals, environmental protection and other industries. However, existing cellulases have several problems that limit their wider applications, including the low turnover number for solid cellulosic materials, and low stability in adapting to various application conditions. For example, high temperature, low pH, and so on. Application of directed evolution technology may be one of the most effective ways for improving the characteristics of cellulases. This paper presents a brief review of the cellulose hydrolysis mechanism by cellulase, advances in cellulases (endoglucanase and β-glucosidase) improvement by directed evolution for several characteristics (for instance, thermal stability, pH adaptability and enzyme activity), limitations of directed evolution for cellulases, and the outlook for directed evolution for cellulase.     

Nest desertion is not predicted by cuckoldry in the Eurasian penduline tit

Engagement in extra-pair copulations is an example of the abundant conflicting interests between males and females over reproduction. Potential benefits for females and the risk of cuckoldry for males are expected to have important implications on the evolution of parental care. However, whether parents adjust parental care in response to parentage remains unclear. In Eurasian penduline tits Remiz pendulinus, which are small polygamous songbirds, parental care is carried out either by the male or by the female. In addition, one third of clutches is deserted by both male and female. Desertion takes place during the egg-laying phase. Using genotypes of nine microsatellite loci of 443 offspring and 211 adults, we test whether extra-pair paternity predicts parental care. We expect males to be more likely to desert cuckolded broods, whereas we expect females, if they obtain benefits from having multiple sires, to be more likely to care for broods with multiple paternity. Our results suggest that parental care is not adjusted to parentage on an ecological timescale. Furthermore, we found that male attractiveness does not predict cuckoldry, and we found no evidence for indirect benefits for females (i.e., increased growth rates or heterozygosity of extra-pair offspring). We argue that male Eurasian penduline tits may not be able to assess the risk of cuckoldry; thus, a direct association with parental care is unlikely to evolve. However, timing of desertion (i.e., when to desert during the egg-laying phase) may be influenced by the risk of cuckoldry. Future work applying extensive gene sequencing and quantitative genetics is likely to further our understanding of how selection may influence the association between parentage and parental care.     

某有色金属企业污水处理厂污水处理工艺

对有色金属冶炼过程中产生的废水按特征因子的不同进行分质处理。其中,高浓度氨氮废水采用三级氨氮吹脱、吸收工艺进行脱氨预处理;含砷酸性废水采用三段中和-铁盐混凝法预处理;经预处理废水混合后,采用石灰法分级沉淀处理废水中重金属离子;然后根据各单位对回用水水质的不同要求,对废水进行深度处理,实现了污水处理后全部回用,污水零排放的目的。并且对污水中的氨、石膏、镍等资源进行回收利用,为企业降低了运行成本,并且防止了二次污染。     

代谢组学技术在环境毒理学研究中的应用

代谢组学作为系统生物学的一部分,通过考察机体受刺激后体液或组织中内源性代谢物的动态变化规律,并结合生物信息统计方法,可系统全面地揭示内因和外因作用于机体的毒性效应和机制。代谢组学技术具有快速、灵敏度高、选择性强的特点,逐渐在低剂量环境污染物长期暴露的毒性效应评估方面发挥出优势。本文综述了代谢组学技术的主要研究手段,在毒理学研究中的发展历程和优点,以及在环境毒理学研究中的应用及前景展望。重点讨论了代谢组学技术在重金属和持久性有机污染物(POPs)毒性评估以及环境胁迫耐受性评价中的应用。     

林下凋落物去除与施氮对针叶林和阔叶林土壤氮的影响

通过野外模拟试验,选择中亚热带针叶林(杉木林)和阔叶林(浙江桂林和罗浮栲林)森林生态系统,设3个施氮水平CK(对照)、低氮〔30kg/(hm2·a) 〕和高氮〔100kg/(hm2·a)〕及2个凋落物处理,研究施氮对土壤主要形态氮质量分数的影响、动态变化及凋落物在其中的作用. 结果表明:与CK相比,高氮处理可瞬时(3d)提高森林土壤氮质量分数,但施氮后持续效应的影响降低. 与保留凋落物相比,去除凋落物在施氮的持续效应中,可降低阔叶林土壤w(铵态氮)18.2%,而杉木林土壤的氮质量分数则略有升高.去除凋落物下施氮的持续和瞬时效应可增加各种林下土壤的w(硝态氮),其中浙江桂林土壤w(硝态氮)分别增加58.9%和38.2%,罗浮栲林土壤分别增加7.0%和30.0%,杉木林土壤分别增加-17.1%和9.0%. 可见凋落物在施氮连续事件中存在复杂的短期和长期相互影响. 阔叶林土壤w(SON)(SON为可溶性有机氮)较高,并且其微生物w(SON)及其占微生物w(TN)的比例高于杉木林土壤,而杉木林土壤微生物w(铵态氮)及其占微生物w(TN)的比例高于阔叶林土壤.      

Pollution characteristics and potential health risk of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) in soil/sediment from Baiyin City, North West, China

In order to better understand the environmental behaviors of persistent organic pollutants, the characteristics of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs) were investigated in twenty-three soil/sediment samples from Baiying City, Northwest China, in 2008. The possible sources and potential health risk of PCDD/Fs were also discussed. The concentrations of PCDD/Fs in nineteen soil samples varied between 20.13 and 496.26 pg/g dry weight (dw.), with an average value of 125.59 pg/g dw. The highest International Toxic Equivalent (I-TEQ) of PCDD/Fs (8.34 pg/g dw.) in soil was found at sample S1 collected from proximity to a copper metallurgy plant. The concentrations of PCDD/Fs in four sediment samples ranged from 37.69 to 491.49 pg/g dw., with an average value of 169.95 pg/g dw. The highest I-TEQ of PCDD/Fs (8.56 pg/g dw.) in sediment was found at sample S12 collected from the East big ditch with waste water discharged into the Yellow River. The results indicated that PCDD/Fs contamination of soil/sediment is originated from three sources: chlorine-containing chemicals, non-ferrous metal industrial PCDD/Fs emission and coal burning. The health risk exposure to PCDD/Fs through soil, dust ingestion and dermal absorption ranged from 0.0006 to 0.0134 pg/kg/day Word Health Organization’s toxic equivalent in 1998 (WHO₁₉₉₈-TEQ) with mean values 0.0032 pg WHO₁₉₉₈-TEQ for adults and varied between 0.0012 and 0.0256 pg/kg/day WHO₁₉₉₈-TEQ with mean values 0.006 pg/kg/day WHO₁₉₉₈-TEQ for children, respectively. These results indicated that health risk of PCDD/Fs for children should be paid more attention.     

In vitro evaluation of human liver cancer cells and the potential cytotoxicity of Tecoma stans (Bignoniaceae) and Brickellia cavanillesi (Asteraceae) both single and in combination

Medicinal herbs are steadily increasing in complementary use for chronic and alterative therapies. The health risks associated with herbal supplements have therefore been identified as a top research priority. Tecoma stans (Tronadora), a Bignoniaceae plant, is a herbal drug traditionally consumed as tea in South America for the control of diabetes. It contains the alkaloids of tecomine and tecostanine which were shown as functional compounds responsible for hypoglycemic activity. However, the side effects of aqueous extracts of this herbal tea have not been reported. In this study, studies sought to evaluate the cytotoxicity of water extracts from T. stans in human hepatoblastoma (HepG2). Toxic effects of T. stans were concentration- and time-dependent in the presence and absence of fetal bovine serum (FBS). Cells were incubated for up to 72-h with varying concentrations of herbal extracts (60–100%), cytotoxicity was determined spectrophotometrically by MTT and reported in terms of % cell viability. For IC₅₀ assay (24 h exposure), cytotoxicity was found at concentration of 60–100%. Evaluation of the effects of T. stans and Brickellia cavanillesi (Asteraceae) in combination revealed that extracts of both herbal extracts' nontoxic levels of T. stans significantly reduced cell viability in a time-dependent manner. Further studies are needed regarding the identification, toxicity, and molecular mechanism of action of active compounds, as well as their cytotoxicity to other cell lines following exposure to both single and combined herbal extracts of these plants with anti-diabetic properties.     

Modelling global-scale potential grassland changes in spatio-temporal patterns to global climate change

Grassland is one of the most widespread vegetation types worldwide and plays a significant role in global carbon cycling. Understanding the sensitivity of grassland to climate change and the effect of climate changes on the grassland ecosystems is a key issue in global carbon cycling. One of the goals of this study was to evaluate the three net primary productivity (NPP)–climate models, i.e. the Miami model, the Schuur model and the classification indices-based model. Results indicated that the classification indices-based model was the most effective model at estimating large-scale grassland NPP. In this research, changes in the spatial pattern of global potential grassland from recent past (1950–2000) to future (2001–2050) A2a scenario were analysed with the integrated orderly classification system of grassland (IOCSG) approach in a Geographic Information System (GIS) environment. NPP was evaluated with the classification indices-based model. Results indicate that under recent past climatic conditions, the main parts of global grassland are the savanna and tundra and alpine grassland and will be converted into the savanna, steppe and semi-desert grassland in A2a scenario. As a whole, areas of grassland will increase by 31.76 million hectares. The classification indices-based model estimated a 12.40% increase of total NPP in grassland from recent past to A2a scenario. It will impose a new issue for future grassland researches to support sustainable development and to provide action relevant knowledge to meet the challenge of climate change.     

Biosorption and biotransformation of crystal violet by Aeromonas hydrophila DN322p

DN322p, an offspring of Aeromonas hydrophila DN322, has the capacity to adsorb and decolorize triphenylmethane dyes in wastewater simultaneously. As a common triphenylmethane dye, crystal violet (CV) was chosen to test the decolorization characteristics of DN322p. Within 0.5 h, the strain DN322p adsorbed a large amount of CV, producing a deep-colored cell pellet and colorless supernatant. The colors of the cell pellet and supernatant lightened over time. The supernatant and dichloromethane extract of the cell pellet both showed conspicuous CV and leuco CV (LCV) characteristic absorbance peaks at 590 nm and 260 nm, respectively, in the UV-vis spectral analysis. This finding indicated that the DN322p cells can adsorb the two dyes. A 99% (w/w) decolorization rate was achieved within 2.5 h with shaking at 30°C for 50 mg CV·L^?1. High Performance Liquid Chromatography (HPLC) analysis of the dichloromethane extract of the supernatant and cell pellet confirmed that CV was mainly converted into its leuco form. Dead cells had a similar adsorption capacity with living cells. About 90% of CV in the dye solution (50 mg·L^?1) was removed by autoclaved cells with an optical delnsity at 600 nm (OD₆₀₀) above 1.0.