The Frequency Dependence of Critical-velocity Behavior in Oscillatory Flow of Superfluid Helium-4 Through a 2-micrometer by 2-micrometer Aperture in a Thin Foil

The critical-velocity behavior of oscillatory superfluid Helium-4 flow through a 2-micrometer by 2-micrometer aperture in a 0.1-micrometer-thick foil has been studied from 0.36 K to 2.10 K at frequencies from less than 50 Hz up to above 1880 Hz. The pressure remained less than 0.5 bar. In early runs during which the frequency remained below 400 Hz, the critical velocity was a nearly-linearly decreasing function of increasing temperature throughout the region of temperature studied. In runs at the lowest frequencies, isolated 2 Pi phase slips could be observed at the onset of dissipation. In runs with frequencies higher than 400 Hz, downward curvature was observed in the decrease of critical velocity with increasing temperature. In addition, above 500 Hz an alteration in supercritical behavior was seen at the lower temperatures, involving the appearance of large energy-loss events. These irregular events typically lasted a few tens of half-cycles of oscillation and could involve hundreds of times more energy loss than would have occurred in a single complete 2 Pi phase slip at maximum flow. The temperatures at which this altered behavior was observed rose with frequency, from ~ 0.6 K and below, at 500 Hz, to ~ 1.0 K and below, at 1880 Hz.Comment: 35 pages, 13 figures, prequel to cond-mat/050203

Investigating self-reported efficacy of lifestyle medicine approaches to tackle erectile dysfunction: a cross-sectional eSurvey based study

Background: Erectile dysfunction (ED) is the most common sexual dysfunction in men. Some types of ED are amenable to treatment using lifestyle medicine approaches with or without pharmacotherapy. Aim: Investigate self-reported efficacy of lifestyle medicine approaches to tackle ED. Methods: A cross-sectional online survey of 1177 community dwelling adults explored the prevalence and methods used to tackle ED in the community setting. We examined differences between participants with and without ED. Variables associated with ED in univariable analyses were included in a multivariable logistic regression to identify variables independently associated with the condition. Outcomes: Self-reported measure: perceived effectiveness of lifestyle medicine interventions to tackle ED. Results: Most respondents (76.5%) had experienced ED, and this was associated with having a long-term condition, taking anti-hypertensive medication, hypercholesterolaemia and obesity. Medication was the most common management strategy overall (65.9%), followed by stress management (43.5%) and weight loss (40.4%). Over half (53.9%) did not use any lifestyle modification strategies to tackle ED. Only 7.0% of ED sufferers received a mental health assessment and 29.2% received other tests (e.g., blood test, medical imaging) by GPs. Cardiovascular training was identified as the best rated strategy by its users (37.8%). Supplements (35.1%) and weight training/physical activity (32.6%) were also positively rated. Clinical implications Structured education to general practitioners and community dwelling adults about the impact of lifestyle behaviour modification and how this could influence the appearance or trajectory of ED could help improve personal choice when tackling ED. Strengths and limitations: To our knowledge, this is the first study to collect eSurvey responses from community dwelling adults to gauge their reliance and perceived effectiveness of lifestyle medicine approaches to tackle ED. The principal limitation was the lack of follow-up, and not recording other information including lifestyle factors such as nutrition, smoking, and the use of alcohol and recreational drugs, which may have enabled a fuller exploration of the factors that could influence the primary outcome measures examined. Conclusion: Despite the high prevalence of ED, there is not enough awareness in the community setting about effective and low-cost lifestyle medicine strategies, including cardiovascular training and the use of supplements and weight training, to help tackle this common condition

Simulations of Vortex Evolution and Phase Slip in Oscillatory Potential Flow of the Superfluid Component of Helium-4 Through an Aperture

The evolution of semicircular quantum vortex loops in oscillating potential flow emerging from an aperture is simulated in some highly symmetrical cases. As the frequency of potential flow oscillation increases, vortex loops that are evolving so as eventually to cross all of the streamlines of potential flow are drawn back toward the aperture when the flow reverses. As a result, the escape size of the vortex loops, and hence the net energy transferred from potential flow to vortex flow in such 2 Pi phase-slip events, decreases as the oscillation frequency increases. Above some aperture-dependent and flow-dependent threshold frequency, vortex loops are drawn back into the aperture. Simulations are preformed using both radial potential flow and oblate-spheroidal potential flow.Comment: 18 pages, 6 figures, sequel to cond-mat/050203

Dietary restriction reduces angiogenesis and growth in an orthotopic mouse brain tumour model

Diet and lifestyle produce major effects on tumour incidence, prevalence, and natural history. Moderate dietary restriction has long been recognised as a natural therapy that improves health, promotes longevity, and reduces both the incidence and growth of many tumour types. Dietary restriction differs from fasting or starvation by reducing total food and caloric intake without causing nutritional deficiencies. No prior studies have evaluated the responsiveness of malignant brain cancer to dietary restriction. We found that a moderate dietary restriction of 30–40% significantly inhibited the intracerebral growth of the CT-2A syngeneic malignant mouse astrocytoma by almost 80%. The total dietary intake for the ad libitum control group (n=9) and the dietary restriction experimental group (n=10) was about 20 and 13 Kcal day−1, respectively. Overall health and vitality was better in the dietary restriction-fed mice than in the ad libitum-fed mice. Tumour microvessel density (Factor VIII immunostaining) was two-fold less in the dietary restriction mice than in the ad libitum mice, whereas the tumour apoptotic index (TUNEL assay) was three-fold greater in the dietary restriction mice than in the ad libitum mice. CT-2A tumour cell-induced vascularity was also less in the dietary restriction mice than in the ad libitum mice in the in vivo Matrigel plug assay. These findings indicate that dietary restriction inhibited CT-2A growth by reducing angiogenesis and by enhancing apoptosis. Dietary restriction may shift the tumour microenvironment from a proangiogenic to an antiangiogenic state through multiple effects on the tumour cells and the tumour-associated host cells. Our data suggest that moderate dietary restriction may be an effective antiangiogenic therapy for recurrent malignant brain cancers

Role of novel targeted therapies in the clinic

The number and variety of novel, molecular-targeted agents offers realistic hope for significant advances in cancer treatment. The potential of these new treatment approaches is unquestionable, but the reality is something that only thorough clinical evaluation and experience can reveal. Clinical experience of targeted therapies is at an early stage but it is likely that we will have an increasing number of treatment options available to us in the near future. This manuscript explores our current understanding of molecular-targeted therapies and considers: What approach should be used? (single vs multitarget agents); When should they be administered? (identifying the optimal point for intervention); How should they be used? (monotherapy or combination therapy regimens); and Who should we be giving them to? (acknowledging the need for patient selection)