EBSD analysis of a Ti-IF steel subjected to hot torsion in the ferritic region

The effect of grain size on the warm deformation behaviour of a titanium stabilized interstitial free steel was investigated using hot torsion. Tests were performed at temperatures between 765 °C and 850 °C at strain rates between 0.003 s⁻¹ and 1 s⁻¹ for samples with grain sizes of 25 μm, 75 μm and 150 μm. The structures were observed using EBSD analysis and are consistent with those expected for materials dominated by dynamic recovery. Some evidence was found for small amounts of thermally induced migration of pre-existing boundary (bulging) and for the generation of new segments of high angle boundaries by continuous dynamic recrystallization. The early onset of a steady-state flow stress in the finer grained samples is attributed to one or a combination of thermally induced boundary migration and enhanced rates of recovery near subgrain (and grain) boundaries.     

Ozone-initiated chemistry in an occupied simulated aircraft cabin

We have used multiple analytical methods to characterize the gas-phase products formed when ozone was added to cabin air during simulated 4-hour flights that were conducted in a reconstructed section of a B-767 aircraft containing human occupants. Two separate groups of 16 females were each exposed to four conditions: low air exchange (4.4 (h-1)), <2 ppb ozone; low air exchange, 61-64 ppb ozone; high air exchange (8.8 h(-1)), <2 ppb ozone; and high air exchange, 73-77 ppb ozone. The addition of ozone to the cabin air increased the levels of identified byproducts from approximately 70 to 130 ppb at the lower air exchange rate and from approximately 30 to 70 ppb at the higher air exchange rate. Most of the increase was attributable to acetone, nonanal, decanal, 4-oxopentanal (4-OPA), 6-methyl-5-hepten-2-one (6-MHO), formic acid, and acetic acid, with 0.25-0.30 mol of quantified product volatilized per mol of ozone consumed. Several of these compounds reached levels above their reported odor thresholds. Most byproducts were derived from surface reactions with occupants and their clothing, consistent with the inference that occupants were responsible for the removal of >55% of the ozone in the cabin. The observations made in this study have implications for other indoor settings. Whenever human beings and ozone are simultaneously present, one anticipates production of acetone, nonanal, decanal, 6-MHO, geranyl acetone, and 4-OPA.     

AneuRx stent graft versus open surgical repair of abdominal aortic aneurysms: multicenter prospective clinical trial

The results of a prospective, nonrandomized, multicenter clinical trial that compared endovascular stent graft exclusion of abdominal aortic aneurysms with open surgical repair are presented. During an 18-month period, 250 patients with infrarenal aneurysms underwent treatment at 12 study sites-190 patients underwent endovascular repair using the Medtronic AneuRx stent graft (Sunnyvale, Calif), and 60 underwent open surgical repair. There was no significant difference in operative mortality rates between the groups. The patients who underwent stent grafting had significant reductions in blood loss, time to extubation, and days in the intensive care unit and in the hospital, with an earlier return to function. The major morbidity rate was reduced from 23% in the surgery group to 12% (P <. 05) in the stent graft group. There was no difference in the combined morbidity/mortality rates between the two groups. Primary technical success at the time of discharge for the patients with stent grafts was 77%, largely as a result of a 21% endoleak rate. At 1 month, the endoleak rate had decreased to 9%. There was no difference in the primary or secondary procedure success rates at 30 days between the surgery and stent graft groups. The primary graft patency rate at 6 months was 98% in the surgery group and 97% in the stent graft group. The aneurysm exclusion rate at 1 month and 6 months was 100% in patients who underwent surgery and 91% in patients who underwent stent grafting. Stent graft migration occurred in three patients and resulted in late endoleaks; each endoleak was corrected by means of endovascular placement of a stent graft extender cuff. There have been no aneurysm ruptures and no surgical conversions to open repair in the stent graft group. Stent graft repair compares favorably with open surgical repair, with a reduced morbidity rate, shortened hospital stays, and satisfactory short term outcomes.     

Comparison of the effects of black and green tea on in vitro lipoprotein oxidation in human serum

Lipoprotein oxidation is a process thought to be involved in atherogenesis. Dietary antioxidants that prevent or inhibit oxidative damage to lipoproteins may help to prevent atherosclerosis. Both black and green teas can be major dietary sources of flavonoids and other phenolics with antioxidant activity. Results of previous studies suggest that green tea may have a greater antioxidant potential than black tea. The aim of this study was to assess and compare the effects of black and green tea on in vitro lipoprotein oxidation. The tea extracts were prepared using a method similar to that used to prepare infusions of tea for drinking. Antioxidant activities of seven black teas and four green teas were assessed using an in vitro assay that measures Cu²⁺ ‐induced oxidation of lipoproteins in human serum. All tea extracts inhibited in vitro lipoprotein oxidation in human serum to a similar extent. No significant difference in antioxidant activity was found between black and green tea. Caffeine prepared to a comparable concentration to that found in tea had no effect on lipoprotein oxidation. Further studies are required to determine the importance of these findings in relation to possible protective effects of black and green tea consumption against atherogenesis and cardiovascular disease. © 1999 Society of Chemical Industry     

Lupin seed coat as a promising food ingredient: physicochemical,nutritional, antioxidant properties,and effect of genotype and environment

The high proportion of seed coat of legume lupins results in big milling lose during kernel flour production, though the seed coat could be value-added as human food. The physicochemical and nutritional properties and antioxidant capacities of seed coats of six Australian sweet lupin cultivars grown at two locations were evaluated. Results showed that genotype, environment and their interaction were significant for seed coat percentage, proximate composition, dietary fibre content, polyphenols and antioxidant capacities. Strong correlations between seed coat lightness and polyphenol content were found. A comparison using multivariate analysis of the seed coat properties showed clear separation based on growing sites. This study indicates the enormous potential of Australian sweet lupin seed coat as an ‘antioxidant dietary fibre’ food source. The results could also benefit to breed varieties with desirable levels of nutrients and phytochemicals.     

Epitaxial Growth of Multi-structure SnO_2 by Chemical Vapor Deposition

The nanowire and whisker heterostructures of tin dioxide were fabricated by the chemical vapor deposition technique.It was demonstrated that various structures of tin oxide can be obtained by controlling the thickness of gold layer and the partial pressure of source vapor at growing sites.12.5 and 25 nm thicknesses are preferable for the epitaxial growth of nanowires and heterostructure through vapor–liquid–solid mechanism,respectively.The tin dioxide whiskers with core-shell structure were fabricated by vapor–solid mechanism.Meanwhile,the influences of various factors on the tin dioxide growth are also discussed.     

A molecular perspective of water at metal interfaces

Water/solid interfaces are relevant to a broad range of physicochemical phenomena and technological processes such as corrosion, lubrication, heterogeneous catalysis and electrochemistry. Although many fields have contributed to rapid progress in the fundamental knowledge of water at interfaces, detailed molecular-level understanding of water/solid interfaces comes mainly from studies on flat metal substrates. These studies have recently shown that a remarkably rich variety of structures form at the interface between water and even seemingly simple flat surfaces. In this Review we discuss the most exciting work in this area, in particular the emerging physical insight and general concepts about how water binds to metal surfaces. We also provide a perspective on outstanding problems, challenges and open questions.