C60 fullerene: a powerful antioxidant or a damaging agent? The importance of an in-depth material characterization prior to toxicity assays

Since the discovery of fullerenes in 1985, these carbon nanospheres have attracted attention regarding their physico/chemical properties. Despite little knowledge about their impact on the environment and human health, the production of fullerenes has already reached an industrial scale. However, the toxicity of C₆₀ is still controversially discussed.The aim of this study was to clarify the biological effects of tetrahydrofuran (THF) suspended C₆₀ fullerene in comparison to water stirred C₆₀ fullerene suspensions. Beyond that, we analyzed the effects on the Crustacea Daphnia magna an indicator for ecotoxicological effects and the human lung epithelial cell line A549 as a simplified model for the respiratory tract.We could demonstrate that water-soluble side products which were formed in THF nC₆₀ suspension were responsible for the observed acute toxic effects, whereas fullerenes themselves had no negative effect regardless of the preparative route on either A549 cell in vitro or D. magna in vivo.     

论当代大学生的信息素养教育

国民信息素养的高低已成为一个国家在全球竞争中获得优势地位的关键,信息素养教育在全世界范围内备受重视。本文以信息素养为出发点,以当今高校对在校大学生信息素养培训的新要求为依据,通过信息的选择、检索、利用,个人创新和文化素养等五个方面的教育,论述了如何培养高校学生信息素养,使学生养成终身学习的习惯。     

Modeling the Hydrology of Climate Change in California’s Sierra Nevada for Subwatershed Scale Adaptation1

Young, Charles A., Marisa I. Escobar‐Arias, Martha Fernandes, Brian Joyce, Michael Kiparsky, Jeffrey F. Mount, Vishal K. Mehta, David Purkey, Joshua H. Viers, and David Yates, 2009. Modeling the Hydrology of Climate Change in California’s Sierra Nevada for Subwatershed Scale Adaptation. Journal of the American Water Resources Association (JAWRA) 45(6):1409‐1423. Abstract: The rainfall‐runoff model presented in this study represents the hydrology of 15 major watersheds of the Sierra Nevada in California as the backbone of a planning tool for water resources analysis including climate change studies. Our model implementation documents potential changes in hydrologic metrics such as snowpack and the initiation of snowmelt at a finer resolution than previous studies, in accordance with the needs of watershed‐level planning decisions. Calibration was performed with a sequence of steps focusing sequentially on parameters of land cover, snow accumulation and melt, and water capacity and hydraulic conductivity of soil horizons. An assessment of the calibrated streamflows using goodness of fit statistics indicate that the model robustly represents major features of weekly average flows of the historical 1980‐2001 time series. Runs of the model for climate warming scenarios with fixed increases of 2°C, 4°C, and 6°C for the spatial domain were used to analyze changes in snow accumulation and runoff timing. The results indicated a reduction in snowmelt volume that was largest in the 1,750‐2,750 m elevation range. In addition, the runoff center of mass shifted to earlier dates and this shift was non‐uniformly distributed throughout the Sierra Nevada. Because the hydrologic model presented here is nested within a water resources planning system, future research can focus on the management and adaptation of the water resources system in the context of climate change.     

Numerical simulations on the influence of matrix diffusion to carbon sequestration in double porosity fissured aquifers

The double porosity model for fissured rocks, such as limestones and dolomites, has some features that may be relevant for carbon sequestration. Numerical simulations were conducted to study the influence of matrix diffusion on the trapping mechanisms relevant for the long-term fate of CO₂ injected in fissured rocks. The simulations show that, due to molecular diffusion of CO₂ into the rock matrix, dissolution trapping and hydrodynamic trapping are more effective in double porosity aquifers than in an equivalent porous media. Mineral trapping, although assessed indirectly, is also probably more relevant in double porosity aquifers due to the larger contact surface and longer contact time between dissolved CO₂ and rock minerals. However, stratigraphic/structural trapping is less efficient in double porosity media, because at short times CO₂ is stored only in the fissures, requiring large aquifer volumes and increasing the risk associated to the occurrence of imperfections in the cap-rock through which leakage can occur. This increased risk is also a reality when considering storage in aquifers with a regional flow gradient, since the CO₂ free-phase will move faster due to the higher flow velocities in fissured media and discharge zones may be reached sooner.     

Methane generation in tropical landfills: simplified methods and field results

This paper deals with the use of simplified methods to predict methane generation in tropical landfills. Methane recovery data obtained on site as part of a research program being carried out at the Metropolitan Landfill, Salvador, Brazil, is analyzed and used to obtain field methane generation over time. Laboratory data from MSW samples of different ages are presented and discussed; and simplified procedures to estimate the methane generation potential, Lo, and the constant related to the biodegradation rate, k are applied. The first order decay method is used to fit field and laboratory results. It is demonstrated that despite the assumptions and the simplicity of the adopted laboratory procedures, the values Lo and k obtained are very close to those measured in the field, thus making this kind of analysis very attractive for first approach purposes.     

The Effect of Masterbatch Addition on the Mechanical, Thermal, Optical and Surface Properties of Poly(lactic acid)

There has been considerable interest in the use of the biodegradable polymer poly(lactic acid) (PLA) as a replacement for petroleum derived polymers due to ease of processability and its high mechanical strength. Other material properties have however limited its wider application. These include its brittle properties, low impact strength and yellow tint. In an attempt to overcome these drawbacks, PLA was blended with four commercially available additives, commonly known as masterbatches. The effect of the addition of 1.5 wt% of the four masterbatches on the mechanical, thermal, optical and surface properties of the polymer was evaluated. All four masterbatches had a slight negative effect on the tensile strength of PLA (3–5% reduction). There was a four fold increase in impact resistance however with the addition of one of the masterbatches. Differential scanning calorimetry demonstrated that this increase corresponded to a decrease in the polymer crystallinity. However there was an associated increase in polymer haze with the addition of this masterbatch. The clarity of PLA was improved through the addition of an optical brightener masterbatch, but the impact resistance remained low. The glass transition and melting temperatures of PLA were not affected by the addition of the masterbatches, and no change was observed in surface energy. Some delay in PLA degradation, in a PBS degradation medium at 50 °C, was observed due to blending with these masterbatches.     

Seat Belt Use in States and Territories with Primary and Secondary Laws -- United States, 2006

Problem

Motor-vehicle crashes are a leading cause of death in the United States. In the event of a crash, seat belts are highly effective in preventing serious injury and death.

Methods

Data from the 2006 Behavioral Risk Factor Surveillance System were used to calculate prevalence of seat belt use by state and territory and by type of state seat belt law (primary vs. secondary enforcement).

Results

In 2006, seat belt use among adults ranged from 58.3% to 91.9% in the states and territories. Seat belt use was 86.0% in states and territories with primary enforcement laws and 75.9% in states with secondary enforcement laws.

Discussion

Seat belt use continues to increase in the United States. Primary enforcement laws remain a more effective strategy than secondary enforcement laws in getting motor-vehicle occupants to wear their seat belts.     

Perceptions matter: household adaptive capacity and capability in two Australian coastal communities

Regional Environmental Change - This paper presents empirical data on household perceptions of capability to adapt to climate hazards and associated capacity needs. Households play an important...     

Fourth-corner correlation is a score test statistic in a log-linear trait–environment model that is useful in permutation testing

Ecologists wish to understand the role of traits of species in determining where each species occurs in the environment. For this, they wish to detect associations between species traits and environmental variables from three data tables, species count data from sites with associated environmental data and species trait data from data bases. These three tables leave a missing part, the fourth-corner. The fourth-corner correlations between quantitative traits and environmental variables, heuristically proposed 20 years ago, fill this corner. Generalized linear (mixed) models have been proposed more recently as a model-based alternative. This paper shows that the squared fourth-corner correlation times the total count is precisely the score test statistic for testing the linear-by-linear interaction in a Poisson log-linear model that also contains species and sites as main effects. For multiple traits and environmental variables, the score test statistic is proportional to the total inertia of a doubly constrained correspondence analysis. When the count data are over-dispersed compared to the Poisson or when there are other deviations from the model such as unobserved traits or environmental variables that interact with the observed ones, the score test statistic does not have the usual chi-square distribution. For these types of deviations, row- and column-based permutation methods (and their sequential combination) are proposed to control the type I error without undue loss of power (unless no deviation is present), as illustrated in a small simulation study. The issues for valid statistical testing are illustrated using the well-known Dutch Dune Meadow data set.     

Green Toxicology: a strategy for sustainable chemical and material development

Green Toxicology refers to the application of predictive toxicology in the sustainable development and production of new less harmful materials and chemicals, subsequently reducing waste and exposure. Built upon the foundation of “Green Chemistry” and “Green Engineering”, “Green Toxicology” aims to shape future manufacturing processes and safe synthesis of chemicals in terms of environmental and human health impacts. Being an integral part of Green Chemistry, the principles of Green Toxicology amplify the role of health-related aspects for the benefit of consumers and the environment, in addition to being economical for manufacturing companies. Due to the costly development and preparation of new materials and chemicals for market entry, it is no longer practical to ignore the safety and environmental status of new products during product development stages. However, this is only possible if toxicologists and chemists work together early on in the development of materials and chemicals to utilize safe design strategies and innovative in vitro and in silico tools. This paper discusses some of the most relevant aspects, advances and limitations of the emergence of Green Toxicology from the perspective of different industry and research groups. The integration of new testing methods and strategies in product development, testing and regulation stages are presented with examples of the application of in silico, omics and in vitro methods. Other tools for Green Toxicology, including the reduction of animal testing, alternative test methods, and read-across approaches are also discussed.