Fate and toxicity of engineered nanomaterials in the environment: A meta-analysis.

The global environment annually receives thousands of tons of engineered nanomaterials (ENMs, particles less than 100 nm diameter). These particles have high active surface area, unique chemical properties, and can enter cells. Humanity uses many ENMs for their biological reactivity (e.g. microbicides), but their environmental effects are complex. We cataloged 2102 experimental results on whole organisms for 22 particle classes (mainly on Ag, Zn, Ti, and Cu) to assess biological responses, effective and lethal concentrations, and bioaccumulation of ENMs. Most responses were negative and varied significantly by particle type, functional group of organism, and type of response. Smaller particles tended to be more toxic. Aquatic organisms responded more negatively than did terrestrial organisms. Animals generally were most sensitive and plants least. Silver ENMs generally had the strongest negative effects. Effective and lethal concentrations generally exceeded modeled environmentally relevant concentrations and organisms usually did not accumulate or biomagnify to concentrations above those in their environment. However, most experiments lasted less than a week and were not field studies. Research to date is probably insufficient to understand chronic effects and long-term biomagnification. Numerous unique and untested ENMs continue to enter environments at accelerating rates, and our analysis indicates potential for negative effects. Our data suggest substantial research is still required to understand the ultimate influence of ENMs as they continue to accumulate in the environment. Around 40% of the papers with experimental data for ENMs failed with respect to reporting means, sample sizes, or experimental error, or they did not have proper experimental design (e.g. lack of true controls). We need more high-quality experiments that are more realistic (field or mesocosm), longer duration, contain a wider range of organisms, and account for complex food web structure.

Positive Aging Views in the General Population Predict Better Long-Term Cognition for Elders in Eight Countries.

Objective: Much of the literature on aging cognitive health has focused on individual determinants, rather than societal ones; in contrast, this study examined whether country-level age status predicts cognitive performance of older individuals over time. Method: Eight countries were examined using a novel combination of country-level age status data from the European Social Survey and individual-level data from the Survey on Health, Ageing, and Retirement in Europe, between 2004 and 2013. Results: We found that more positive age status significantly predicted better performance on three cognitive measures over a 10-year period, after adjusting for relevant covariates. The generalized-linear model nested individuals within countries to account for the multilevel data. Discussion: To our knowledge, this is the first study to report an association between country-level age status and cognitive performance over time. The results suggest that a small change in the perception of old age at the population level could have a significant effect on the cognitive health of older individuals.

Trends and comparison of female first authorship in high impact medical journals: observational study (1994-2014).

OBJECTIVE: To examine changes in representation of women among first authors of original research published in high impact general medical journals from 1994 to 2014 and investigate differences between journals. DESIGN: Observational study. STUDY SAMPLE: All original research articles published in Annals of Internal Medicine, Archives of Internal Medicine, The BMJ, JAMA, The Lancet, and the New England Journal of Medicine (NEJM) for one issue every alternate month from February 1994 to June 2014. MAIN EXPOSURES: Time and journal of publication. MAIN OUTCOME MEASURES: Prevalence of female first authorship and its adjusted association with time of publication and journal, assessed using a multivariable logistic regression model that accounted for number of authors, study type and specialty/topic, continent where the study was conducted, and the interactions between journal and time of publication, study type, and continent. Estimates from this model were used to calculate adjusted odds ratios against the mean across the six journals, with 95% confidence intervals and P values to describe the associations of interest. RESULTS: The gender of the first author was determined for 3758 of the 3860 articles considered; 1273 (34%) were women. After adjustment, female first authorship increased significantly from 27% in 1994 to 37% in 2014 (P<0.001). The NEJM seemed to follow a different pattern, with female first authorship decreasing; it also seemed to decline in recent years in The BMJ but started substantially higher (approximately 40%), and The BMJ had the highest total proportion of female first authors. Compared with the mean across all six journals, first authors were significantly less likely to be female in the NEJM (adjusted odds ratio 0.68, 95% confidence interval 0.53 to 0.89) and significantly more likely to be female in The BMJ (1.30, 1.01 to 1.66) over the study period. CONCLUSIONS: The representation of women among first authors of original research in high impact general medical journals was significantly higher in 2014 than 20 years ago, but it has plateaued in recent years and has declined in some journals. These results, along with the significant differences seen between journals, suggest that underrepresentation of research by women in high impact journals is still an important concern. The underlying causes need to be investigated to help to identify practices and strategies to increase women's influence on and contributions to the evidence that will determine future healthcare policies and standards of clinical practice.