Oxygen vacancy dynamics in Pt/TiOx/TaOy/Pt memristors: exchange with the environment and internal electromigration.

Memristors are expected to be one of the key building blocks for the development of new bio-inspired nanoelectronics. Memristive effects in transition metal oxides are usually linked to the electromigration at the nanoscale of charged oxygen vacancies (OV). In this paper we address, for Pt/TiOx/TaOy/Pt devices, the exchange of OV between the device and the environment upon the application of electrical stress. From a combination of experiments and theoretical simulations we determine that both TiOxand TaOylayers oxidize, via environmental oxygen uptake, during the electroforming process. Once the memristive effect is stabilized (post-forming behavior) our results suggest that oxygen exchange with the environment is suppressed and the OV dynamics that drives the memristive behavior is restricted to an internal electromigration between TiOxand TaOylayers. Our work provides relevant information for the design of reliable binary oxide memristive devices.

Dietary B group vitamin intake and the bladder cancer risk: a pooled analysis of prospective cohort studies.

PURPOSE: Diet may play an essential role in the aetiology of bladder cancer (BC). The B group complex vitamins involve diverse biological functions that could be influential in cancer prevention. The aim of the present study was to investigate the association between various components of the B group vitamin complex and BC risk. METHODS: Dietary data were pooled from four cohort studies. Food item intake was converted to daily intakes of B group vitamins and pooled multivariate hazard ratios (HRs), with corresponding 95% confidence intervals (CIs), were obtained using Cox-regression models. Dose-response relationships were examined using a nonparametric test for trend. RESULTS: In total, 2915 BC cases and 530,012 non-cases were included in the analyses. The present study showed an increased BC risk for moderate intake of vitamin B1 (HRB1: 1.13, 95% CI: 1.00-1.20). In men, moderate intake of the vitamins B1, B2, energy-related vitamins and high intake of vitamin B1 were associated with an increased BC risk (HR (95% CI): 1.13 (1.02-1.26), 1.14 (1.02-1.26), 1.13 (1.02-1.26; 1.13 (1.02-1.26), respectively). In women, high intake of all vitamins and vitamin combinations, except for the entire complex, showed an inverse association (HR (95% CI): 0.80 (0.67-0.97), 0.83 (0.70-1.00); 0.77 (0.63-0.93), 0.73 (0.61-0.88), 0.82 (0.68-0.99), 0.79 (0.66-0.95), 0.80 (0.66-0.96), 0.74 (0.62-0.89), 0.76 (0.63-0.92), respectively). Dose-response analyses showed an increased BC risk for higher intake of vitamin B1 and B12. CONCLUSION: Our findings highlight the importance of future research on the food sources of B group vitamins in the context of the overall and sex-stratified diet.

Anthropometric measures, physical activity, and risk of glioma and meningioma in a large prospective cohort study.

Body fatness has been associated with increased risk of a number of hormone-dependent cancers. Recent studies suggest that body mass index (BMI) may be related to meningiomas, which are more common in women than men, and for which estrogens are believed to play a role. Using data from a large European propective cohort, 203 incident cases of meningioma and 340 cases of glioma were included in the analysis for measures of body fat, height, and physical activity among 380,775 participants. All analyses were conducted using Cox proportional hazards model and controlling for age, sex, country, and education. A 71% increase in risk of meningioma was observed among men and women in the top quartile of waist circumference (HR = 1.71, 95% CI = 1.08-2.73, P(trend) = 0.01). A positive association was also observed for BMI and meningioma (HR = 1.48, 95% CI = 0.98-2.23, for BMI ≥30 compared with a BMI of 20-24.9, P(trend) = 0.05). An association with height and meningioma was also suggestive (HR = 1.24, 95% 0.96-1.51, for each 10 cm increase). In contrast, no associations were observed for height and different measures of body fat and risk of glioma. Physical activity was not related to either type of brain tumors. Results from this study support an increase in risk of meningioma with higher body fatness among both men and women. No association was observed between anthropometric measures and risk of glioma.

Dietary sources of vitamin C, vitamin E and specific carotenoids in Spain.

A cross-sectional study was conducted within the Spanish cohort of the European Prospective Investigation in Cancer and Nutrition to assess the principal food sources of vitamin C, vitamin E, alpha-carotene, beta-carotene, lycopene, lutein, beta-cryptoxanthin and zeaxanthin in an adult Spanish population. The study included 41446 healthy volunteers (25812 women and 15634 men), aged 29-69 years, from three Spanish regions in the north (Asturias, Navarra and Guipúzcoa) and two in the south (Murcia and Granada). Usual food intake was estimated by personal interview through a computerized version of a dietary history questionnaire. Foods that provided at least two-thirds of the studied nutrients were: fruits (mainly oranges) (51 %) and fruiting vegetables (mainly tomato and sweet pepper) (20 %) for vitamin C; vegetable oils (sunflower and olive) (40 %), non-citrus fruits (10 %), and nuts and seeds (8 %) for vitamin E; root vegetables (carrots) (82 %) for alpha-carotene; green leafy (28 %), root (24 %) and fruiting vegetables (22 %) for beta-carotene; fruiting vegetables (fresh tomato) (72 %) for lycopene; green leafy vegetables (64 %) for lutein; citrus fruits (68 %) for beta-cryptoxanthin; citrus fruits (43 %) and green leafy vegetables (20 %) for zeaxanthin. In conclusion, the main food sources of nutrients with redox properties have been identified in a Mediterranean country. This could provide an insight into the interpretation of epidemiological studies investigating the role of diet in health and disease.