Deformation of Silica Aerogel During Fluid Adsorption

Aerogels are very compliant materials - even small stresses can lead to large deformations. In this paper we present measurements of the linear deformation of high porosity aerogels during adsorption of low surface tension fluids, performed using a Linear Variable Differential Transformer (LVDT). We show that the degree of deformation of the aerogel during capillary condensation scales with the surface tension, and extract the bulk modulus of the gel from the data. Furthermore we suggest limits on safe temperatures for filling and emptying low density aerogels with helium.Comment: 8 pages, 5 figures, submitted to PR

Hydrocarbon degradation, plant colonization and gene expression of alkane degradation genes by endophytic Enterobacter ludwigii strains

The genus Enterobacter comprises a range of beneficial plant-associated bacteria 2 showing plant growth-promotion. Enterobacter ludwigii belongs to the Enterobacter 3 cloacae complex and has been reported to include human pathogens but also plant-4 associated strains with plant beneficial capacities. To assess the role of Enterobacter 5 endophytes in hydrocarbon degradation, plant colonization, abundance and expression of 6 CYP153 genes in different plant compartments, three plant species (Italian ryegrass, 7 birdsfoot trefoil and alfalfa) were grown in sterile soil spiked with 1% diesel and 8 inoculated with three endophytic Enterobacter ludwigii strains. Results showed that all 9 strains were capable of hydrocarbon degradation and efficiently colonized the 10 rhizosphere and plant interior. Two strains, ISI10-3 and BRI10-9, showed highest 11 degradation rates of diesel fuel up to 68% and performed best in combination with Italian 12 ryegrass and alfalfa. All strains expressed the CYP153 gene in all plant compartments, 13 indicating an active role in degradation of diesel in association with plants.Higher Education Commission of Pakistanhttp://www.sciencedirect.com/science/journal/0269749

Differential drought-induced modulation of ozone tolerance in winter wheat species

Recent reports challenge the widely accepted idea that drought may offer protection against ozone (O3) damage in plants. However, little is known about the impact of drought on the magnitude of O3 tolerance in winter wheat species. Two winter wheat species with contrasting sensitivity to O3 (O3 tolerant, primitive wheat, T. turgidum ssp. durum; O3 sensitive, modern wheat, T. aestivum L. cv. Xiaoyan 22) were exposed to O3 (83ppb O3, 7h d−1) and/or drought (42% soil water capacity) from flowering to grain maturity to assess drought-induced modulation of O3 tolerance. Plant responses to stress treatments were assessed by determining in vivo biochemical parameters, gas exchange, chlorophyll a fluorescence, and grain yield. The primitive wheat demonstrated higher O3 tolerance than the modern species, with the latter exhibiting higher drought tolerance than the former. This suggested that there was no cross-tolerance of the two stresses when applied separately in these species/cultivars of winter wheat. The primitive wheat lost O3 tolerance, while the modern species showed improved tolerance to O3 under combined drought and O3 exposure. This indicated the existence of differential behaviour of the two wheat species between a single stress and the combination of the two stresses. The observed O3 tolerance in the two wheat species was related to their magnitude of drought tolerance under a combination of drought and O3 exposure. The results clearly demonstrate that O3 tolerance of a drought-sensitive winter wheat species can be completely lost under combined drought and O3 exposure

Anastrozole versus tamoxifen for the prevention of locoregional and contralateral breast cancer in postmenopausal women with locally excised ductal carcinoma in situ (IBIS-II DCIS): a double-blind, randomised controlled trial

Background Third-generation aromatase inhibitors are more effective than tamoxifen for preventing recurrence in postmenopausal women with hormone-receptor-positive invasive breast cancer. However, it is not known whether anastrozole is more effective than tamoxifen for women with hormone-receptor-positive ductal carcinoma in situ (DCIS). Here, we compare the efficacy of anastrozole with that of tamoxifen in postmenopausal women with hormone-receptor-positive DCIS. Methods In a double-blind, multicentre, randomised placebo-controlled trial, we recruited women who had been diagnosed with locally excised, hormone-receptor-positive DCIS. Eligible women were randomly assigned in a 1:1 ratio by central computer allocation to receive 1 mg oral anastrozole or 20 mg oral tamoxifen every day for 5 years. Randomisation was stratified by major centre or hub and was done in blocks (six, eight, or ten). All trial personnel, participants, and clinicians were masked to treatment allocation and only the trial statistician had access to treatment allocation. The primary endpoint was all recurrence, including recurrent DCIS and new contralateral tumours. All analyses were done on a modified intention-to-treat basis (in all women who were randomised and did not revoke consent for their data to be included) and proportional hazard models were used to compute hazard ratios and corresponding confidence intervals. This trial is registered at the ISRCTN registry, number ISRCTN37546358. Results Between March 3, 2003, and Feb 8, 2012, we enrolled 2980 postmenopausal women from 236 centres in 14 countries and randomly assigned them to receive anastrozole (1449 analysed) or tamoxifen (1489 analysed). Median follow-up was 7·2 years (IQR 5·6–8·9), and 144 breast cancer recurrences were recorded. We noted no statistically significant difference in overall recurrence (67 recurrences for anastrozole vs 77 for tamoxifen; HR 0·89 [95% CI 0·64–1·23]). The non-inferiority of anastrozole was established (upper 95% CI <1·25), but its superiority to tamoxifen was not (p=0·49). A total of 69 deaths were recorded (33 for anastrozole vs 36 for tamoxifen; HR 0·93 [95% CI 0·58–1·50], p=0·78), and no specific cause was more common in one group than the other. The number of women reporting any adverse event was similar between anastrozole (1323 women, 91%) and tamoxifen (1379 women, 93%); the side-effect profiles of the two drugs differed, with more fractures, musculoskeletal events, hypercholesterolaemia, and strokes with anastrozole and more muscle spasm, gynaecological cancers and symptoms, vasomotor symptoms, and deep vein thromboses with tamoxifen. Conclusions No clear efficacy differences were seen between the two treatments. Anastrozole offers another treatment option for postmenopausal women with hormone-receptor-positive DCIS, which may be be more appropriate for some women with contraindications for tamoxifen. Longer follow-up will be necessary to fully evaluate treatment differences