Short versus long silver nanowires: a comparison of in vivo pulmonary effects post instillation.

BackgroundSilver nanowires (Ag NWs) are increasingly being used to produce touchscreens for smart phones and computers. When applied in a thin film over a plastic substrate, Ag NWs create a transparent, highly-conductive network of fibers enabling the touch interface between consumers and their electronics. Large-scale application methods utilize techniques whereby Ag NW suspensions are deposited onto substrates via droplets. Aerosolized droplets increase risk of occupational Ag NW exposure. Currently, there are few published studies on Ag NW exposure-related health effects. Concerns have risen about the potential for greater toxicity from exposure to high-aspect ratio nanomaterials compared to their non-fibrous counterparts. This study examines whether Ag NWs of varying lengths affect biological responses and silver distribution within the lungs at different time-points.MethodsTwo different sizes of Ag NWs (2 μm [S-Ag NWs] and 20 μm [L-Ag NWs]) were tested. Male, Sprague-Dawley rats were intratracheally instilled with Ag NWs (0, 0.1, 0.5, or 1.0 mg/kg). Broncho-alveolar lavage fluid (BALF) and lung tissues were obtained at 1, 7, and 21 days post exposure for analysis of BAL total cells, cell differentials, and total protein as well as tissue pathology and silver distribution.Results and conclusionsThe two highest doses produced significant increases in BAL endpoints. At Day 1, Ag NWs increased total cells, inflammatory polymorphonuclear cells (PMNs), and total protein. PMNs persisted for both Ag NW types at Day 7, though not significantly so, and by Day 21, PMNs appeared in line with sham control values. Striking histopathological features associated with Ag NWs included 1) a strong influx of eosinophils at Days 1 and 7; and 2) formation of Langhans and foreign body giant cells at Days 7 and 21. Epithelial sloughing in the terminal bronchioles (TB) and cellular exudate in alveolar regions were also common. By Day 21, Ag NWs were primarily enclosed in granulomas or surrounded by numerous macrophages in the TB-alveolar duct junction. These findings suggest short and long Ag NWs produce pulmonary toxicity; thus, further research into exposure-related health effects and possible exposure scenarios are necessary to ensure human safety as Ag NW demand increases

Lava channel formation during the 2001 eruption on Mount Etna: evidence for mechanical erosion

We report the direct observation of a peculiar lava channel that was formed near the base of a parasitic cone during the 2001 eruption on Mount Etna. Erosive processes by flowing lava are commonly attributed to thermal erosion. However, field evidence strongly suggests that models of thermal erosion cannot explain the formation of this channel. Here, we put forward the idea that the essential erosion mechanism was abrasive wear. By applying a simple model from tribology we demonstrate that the available data agree favorably with our hypothesis. Consequently, we propose that erosional processes resembling the wear phenomena in glacial erosion are possible in a volcanic environment.Comment: accepted for publication in Physical Review Letter

Biomass burning and pollution aerosol over North America: Organic components and their influence on spectral optical properties and humidification response

Thermal analysis of aerosol size distributions provided size resolved volatility up to temperatures of 400°C during extensive flights over North America (NA) for the INTEX/ICARTT experiment in summer 2004. Biomass burning and pollution plumes identified from trace gas measurements were evaluated for their aerosol physiochemical and optical signatures. Measurements of soluble ionic mass and refractory black carbon (BC) mass, inferred from light absorption, were combined with volatility to identify organic carbon at 400°C (VolatileOC) and the residual or refractory organic carbon, RefractoryOC. This approach characterized distinct constituent mass fractions present in biomass burning and pollution plumes every 5–10 min. Biomass burning, pollution and dust aerosol could be stratified by their combined spectral scattering and absorption properties. The “nonplume” regional aerosol exhibited properties dominated by pollution characteristics near the surface and biomass burning aloft. VolatileOC included most water-soluble organic carbon. RefractoryOC dominated enhanced shortwave absorption in plumes from Alaskan and Canadian forest fires. The mass absorption efficiency of this RefractoryOC was about 0.63 m2 g−1 at 470 nm and 0.09 m2 g−1 at 530 nm. Concurrent measurements of the humidity dependence of scattering, γ, revealed the OC component to be only weakly hygroscopic resulting in a general decrease in γ with increasing OC mass fractions. Under ambient humidity conditions, the systematic relations between physiochemical properties and γ lead to a well-constrained dependency on the absorption per unit dry mass for these plume types that may be used to challenge remotely sensed and modeled optical properties

Making a home, finding a job: investigating early housing and employment outcomes for young people leaving care

This paper presents findings from a new study of outcomes for young people leaving care funded by the Department for Education and Skills. It reports findings for a sample of 106 young people in relation to progress made in housing and employment some 12-15 months after leaving care. The generally poor employment outcomes of care leavers are acknowledged, but ingredients that make for success are also highlighted, including the value of settled care and post-care careers, sound career planning and, significantly, the value of delaying young people's transitions from care. Early career paths also interconnect with how young people fare in housing, in developing life skills and with other problems in their lives after leaving care. Housing outcomes were more encouraging and predominantly shaped by events after leaving care, and faring well in housing was the factor most closely associated with positive mental well-being in young people. Some groups that are at risk of faring badly are identified, including young people with mental-health problems, young people with persistent offending or substance misuse problems and, in some respects, young disabled people. The implications of these findings for leaving care services are considered

Acceptability of Condom Promotion and Distribution Among 10-19 Year-Old Adolescents in Mpwapwa and Mbeya Rural Districts, Tanzania.

\ud The HIV/AIDS pandemic remains a leading challenge for global health. Although condoms are acknowledged for their key role on preventing HIV transmission, low and inappropriate use of condoms persists in Tanzania and elsewhere in Africa. This study assesses factors affecting acceptability of condom promotion and distribution among adolescents in Mpwapwa and Mbeya rural districts of Tanzania. Data were collected in 2011 as part of a larger cross-sectional survey on condom use among 10-19 year-olds in Mpwapwa and Mbeya rural districts of Tanzania using a structured questionnaire. Associations between acceptability of condom promotion and distribution and each of the explanatory variables were tested using Chi Square. Multivariate logistic regression model was used to examine independent predictors of the acceptability of condom promotion and distribution using STATA (11) statistical software at 5% significance level. Mean age of the 1,327 adolescent participants (50.5% being males) was 13.5 years (SD = 1.4). Acceptance of condom promotion and distribution was found among 37% (35% in Mpwapwa and 39% in Mbeya rural) of the adolescents. Being sexually active and aged 15-19 was the strongest predictor of the acceptability of condom promotion and distribution (OR = 7.78, 95% CI 4.65-12.99). Others were; not agreeing that a condom is effective in preventing transmissions of STIs including HIV (OR = 0.34, 95% CI 0.20-0.56), being a resident of Mbeya rural district (OR = 1.67, 95% CI 1.28-2.19), feeling comfortable being seen by parents/guardians holding/buying condoms (OR = 2.20, 95% CI 1.40-3.46) and living with a guardian (OR = 1.48, 95% CI 1.08-2.04). Acceptability of condom promotion and distribution among adolescents in Mpwapwa and Mbeya rural is low. Effect of sexual activity on the acceptability of condom promotion and distribution is age-dependent and was the strongest. Feeling comfortable being seen by parents/guardians buying or holding condoms, perceived ability of condoms to offer protection against HIV/AIDS infections, district of residence and living arrangements also offered significant predictive effect. Knowledge of these factors is vital in designing successful and sustainable condom promotion and distribution programs in Tanzania.\u

Relationships between paranoid thinking, self-esteem and the menstrual cycle.

This study aimed to investigate whether paranoid experiences and levels of self-esteem fluctuate over the menstrual cycle and whether levels of self-esteem are lower when perceived persecution is felt to be deserved. Measures of anxiety, depression, persecution, deservedness and self-esteem were completed on-line by 278 women over their menstrual cycle. Responses were compared at the paramenstrual (3 days before and after menses onset) and mid-cycle phase. At the paramenstrual phase persecution, negative self-esteem, anxiety and depression were higher and positive self-esteem was lower than at mid-cycle. A greater proportion of women experienced persecution as deserved at the paramenstrual phase. This was associated with higher depression and negative self-esteem scores. Increased levels of deservedness significantly strengthened the relationship between persecution and negative, but not positive, self-esteem. These findings suggest that the paramenstrual phase is a time of vulnerability to increased paranoid experiences, an increased likelihood that feelings of persecution will feel deserved and lowered self-esteem. The findings support the view that interpersonal sensitivities may be key to menstrual cycle symptoms and have an impact on relationships. Further, the study illustrated that ideas developed for psychosis could make a valuable contribution to understanding and managing this aspect of menstruation-related distress

HIV infection and sexual risk among men who have sex with men and women (MSMW): A systematic review and meta-analysis

Objectives: To estimate the number of men who have sex with men and women who are HIV-positive in the United States, and to compare HIV prevalence rates between men who have sex with men and women, men who have sex with men only, and men who have sex with women exclusively. Methods: Following PRISMA guidelines, we conducted a systematic review and meta-analysis of reports referencing HIV prevalence and men who have sex with men and women. We searched PubMed and Ovid PsycINFO for peer-reviewed, U.S.-based articles reporting on HIV prevalence among men who have sex with men and women. We conducted event rate, effect size, moderation and sensitivity analyses. Results: We estimate that 1.0% of U.S. males are bisexually-behaving, and that 121,800 bisexually-behaving men are HIV-positive. Men who have sex with men and women are less than half as likely to be HIV-positive as men who have sex with men only (16.9% vs. 33.3%; OR = 0.41, 95% CI: 0.31, 0.54), but more than five times as likely to be HIV-positive as men who have sex with women exclusively (18.3% vs. 3.5%; OR = 5.71, 95% CI: 3.47, 9.39). They are less likely to engage in unprotected receptive anal intercourse than men who have sex with men only (15.9% vs. 35.0%; OR = 0.36, 95% CI: 0.28, 0.46). Men who have sex with men and women in samples with high racial/ethnic minority proportions had significantly higher HIV prevalence than their counterparts in low racial/ethnic minority samples. Conclusions: This represents the first meta-analysis of HIV prevalence in the U.S. between men who have sex with men and women and men who have sex with men only. Data collection, research, and HIV prevention and care delivery specifically tailored to men who have sex with men and women are necessary to better quantify and ameliorate this population's HIV burden. © 2014 Friedman et al

Rapid VAC high dose melphalan regimen, a novel chemotherapy approach in childhood soft tissue sarcomas.

Forty-three children with malignant soft tissue sarcomas (IRS Groups II-IV) were treated with rapid dose delivery chemotherapy protocol comprising six courses of vincristine, adriamycin and cyclophosphamide, given in most cases within 8 weeks (Rapid VAC). This was followed in 36 patients by high dose melphalan with autologous bone marrow rescue. Twenty-six patients also received irradiation to the site of primary tumour. The Rapid VAC regimen was well tolerated and largely administered as an out-patient. There was one toxic death which occurred 2 months after high dose melphalan due to a combination of infection and possible anthracycline cardiomyopathy. Stages were, (Intergroup Rhabdomyosarcoma Study (IRS) system) Group, Group II--four patients. Group III--27 patients and Group IV--12 patients; International Society of Paediatric Oncology (SIOP) staging, Stage I--11, Stage II--13, Stage III--7, Stage IV--12. Actuarial survival at 5 years for all stages is 57% and event free survival 44%. For patients with non-metastatic diseases, 62% and 53% respectively. This treatment strategy utilises the philosophy of rapid drug delivery with high dose consolidation and enables all chemotherapy to be finished within a 4 month period. In general, a conservative approach was applied to both radiation and surgery to minimise late sequelae related to these treatment modalities. Although the small number of high risk patients in this study limits conclusions regarding efficacy in these subgroups the overall results with this regimen appear to be comparable to that with other approaches

Translational toxicology in setting occupational exposure limits for dusts and hazard classification – a critical evaluation of a recent approach to translate dust overload findings from rats to humans

Background We analyze the scientific basis and methodology used by the German MAK Commission in their recommendations for exposure limits and carcinogen classification of “granular biopersistent particles without known specific toxicity” (GBS). These recommendations are under review at the European Union level. We examine the scientific assumptions in an attempt to reproduce the results. MAK’s human equivalent concentrations (HECs) are based on a particle mass and on a volumetric model in which results from rat inhalation studies are translated to derive occupational exposure limits (OELs) and a carcinogen classification. Methods We followed the methods as proposed by the MAK Commission and Pauluhn 2011. We also examined key assumptions in the metrics, such as surface area of the human lung, deposition fractions of inhaled dusts, human clearance rates; and risk of lung cancer among workers, presumed to have some potential for lung overload, the physiological condition in rats associated with an increase in lung cancer risk. Results The MAK recommendations on exposure limits for GBS have numerous incorrect assumptions that adversely affect the final results. The procedures to derive the respirable occupational exposure limit (OEL) could not be reproduced, a finding raising considerable scientific uncertainty about the reliability of the recommendations. Moreover, the scientific basis of using the rat model is confounded by the fact that rats and humans show different cellular responses to inhaled particles as demonstrated by bronchoalveolar lavage (BAL) studies in both species. Conclusion Classifying all GBS as carcinogenic to humans based on rat inhalation studies in which lung overload leads to chronic inflammation and cancer is inappropriate. Studies of workers, who have been exposed to relevant levels of dust, have not indicated an increase in lung cancer risk. Using the methods proposed by the MAK, we were unable to reproduce the OEL for GBS recommended by the Commission, but identified substantial errors in the models. Considerable shortcomings in the use of lung surface area, clearance rates, deposition fractions; as well as using the mass and volumetric metrics as opposed to the particle surface area metric limit the scientific reliability of the proposed GBS OEL and carcinogen classification.International Carbon Black Associatio

Characterization of the binding sites of the anticancer ruthenium(III) complexes KP1019 and KP1339 on human serum albumin via competition studies

Indazolium trans-[tetrachloridobis(1H-indazole)ruthenate(III)] (KP1019) and its Na+ analogue (KP1339) are two of the most prominent non-platinum antitumor metal complexes currently undergoing clinical trials. After intravenous administration, they are known to bind to human serum albumin (HSA) in a noncovalent manner. To elucidate their HSA binding sites, displacement reactions with the established site markers warfarin and dansylglycine as well as bilirubin were monitored by spectrofluorimetry, ultrafiltration-UV-vis spectrophotometry, and/or capillary zone electrophoresis. Conditional stability constants for the binding of KP1019 and KP1339 to sites I and II of HSA were determined, indicating that both Ru(III) compounds bind to both sites with moderately strong affinity (log K (1)' = 5.3-5.8). No preference for either binding site was found, and similar results were obtained for both metal complexes, demonstrating low influence of the counter ion on the binding event