On the nitrogen-induced lattice expansion of a non-stainless austenitic steel, Invar 36®, under triode plasma nitriding

Chromium, as a strong nitride-forming element, is widely regarded to be an “essential” ingredient for the formation of a nitrogen-expanded lattice in thermochemical nitrogen diffusion treatments of austenitic (stainless) steels. In this article, a proprietary “chrome-free” austenitic iron-nickel alloy, Invar® 36 (Fe-36Ni, in wt pct), is characterized after triode plasma nitriding (TPN) treatments at 400 °C to 450 °C and compared with a “stainless” austenitic counterpart RA 330® (Fe-19Cr-35Ni, in wt pct) treated under equivalent nitriding conditions. Cr does indeed appear to play a pivotal role in colossal nitrogen supersaturation (and hence anisotropic lattice expansion and superior surface hardening) of austenitic steel under low-temperature (≤ 450 °C) nitrogen diffusion. Nevertheless, this work reveals that nitrogen-induced lattice expansion occurs below the nitride-containing surface layer in Invar 36 alloy after TPN treatment, implying that Cr is not a necessity for the nitrogen-interstitial induced lattice expansion phenomenon to occur, also suggesting another type of γN

The cardiovascular risk profile of middle-aged women with polycystic ovary syndrome

Objectives: Contradictory results have been reported regarding the association between polycystic ovary syndrome (PCOS) and cardiovascular disease (CVD). We assessed the cardiometabolic phenotype and prevalence of CVD in middle-aged women with PCOS, compared with age-matched controls from the general population, and estimated 10-year CVD risk and cardiovascular health score. Design: A cross-sectional study. Participants: 200 women aged >45 with PCOS, and 200 age-matched controls. Measurements: Anthropometrics, insulin, lipid levels, prevalence of metabolic syndrome and type II diabetes. Ten-year Framingham risk score and the cardiovascular health score were calculated, and carotid intima-media thickness (cIMT) was measured. Results: Mean age was 50.5 years (SD = 5.5) in women with PCOS and 51.0 years (SD = 5.2) in controls. Increased waist circumference, body mass index and hypertension were more often observed in women with PCOS (P <.001). In women with PCOS, the prevalence of type II diabetes and metabolic syndrome was not significantly increased and lipid levels were not different from controls. cIMT was lower in women with PCOS (P <.001). Calculated cardiovascular health and 10-year CVD risk were similar in women with PCOS and controls. Conclusions: Middle-aged women with PCOS exhibit only a moderately unfavourable cardiometabolic profile compared to age-matched controls, even though they present with an increased BMI and waist circumference. Furthermore, we found no evidence for increased (10-year) CVD risk or more severe atherosclerosis compared with controls from the general population. Long-term follow-up of women with PCOS is necessary to provide a definitive answer concerning lon

The Partially Sighted Older Computer User: Assessing the Ease of Use of Two Input Devices

In a computer course, provided by the Royal Dutch Visio, some partially sighted older clients had difficulty operating a computer. Clients are taught to use a keyboard, which may be difficult to use for a number of older adults. Studies comparing input devices conclude that the touch screen results in the greatest task performance for older adults. However, existing research mainly compares older adults without visual impairments. An experiment was conducted which compared task performance of two input devices (keyboard and touch screen) in two age groups (younger and partially sighted older adults). Task execution times and errors were obtained in three computer tasks. The results indicate that the touch screen outperformed the keyboard in both age groups in simple point-and-tap interfaces. But, there are activities and controls that caused difficulties, e.g. entering text and using a scroll bar. ACT-R, an influential cognitive architecture, was used to model task performance of the partially sighted older computer user to better understand the use of input devices. ACT-R parameters were updated to model the effects of age-related changes and visual impairments, which are not presently part of the architecture. Keyboard and touch screen models were developed which simulated task performance in a task from the experiment. Analyses revealed a good fit between the touch screen model and older adult data, although the keyboard model needs some more refinements.

Micorrização e adubação de mudas micropropagadas de antúrio, cv. Eidibel: crescimento e aclimatização ex vitro

Para a formação de mudas, plântulas micropropagadas de antúrio são submetidas a uma das etapas mais críticas na cultura de tecidos de plantas que é da transferência in vitro para ex vitro. O emprego de fungos micorrízicos arbusculares (FMA) que possam promover maior crescimento e sobrevivência da plântula micropropagada pode ser promissor e viável para plantas produzidas em ambiente protegido. O objetivo foi monitorar as respostas fisiológicas das plântulas de antúrio cv. Eidibel sob influência de adubação N:P:K e/ou inoculação de Glomus intraradices. Em uma primeira fase, as plântulas in vitro foram transferidas para bandejas de polipropileno, contendo um substrato a base de casca de Pinus, realizando-se os tratamentos: controle, adubação (Osmocote 15:10:10), inoculação de FMA e adubação, e somente inoculação. As plântulas permaneceram durante 100 dias, quando foram transplantadas para vaso de 1 L, contendo o mesmo substrato. As plântulas do controle foram divididas nos tratamentos: controle/controle, controle/adubação, controle/adubação e inoculação e controle/inoculação, enquanto as plântulas dos demais tratamentos da primeira fase permaneceram da mesma forma. Nesta fase, permaneceram por 450 dias, determinando-se: matéria seca da parte aérea, da raiz, da folha e total, área foliar, relação parte aérea/raiz, relação matéria seca/matéria fresca total e colonização micorrízica. A micorrização das plântulas micropropagadas de antúrio, tanto na fase de aclimatização quanto de obtenção de mudas, não atingiu o mesmo efeito positivo da adubação N:P:K na promoção do crescimento