Structural and dynamical properties of superfluid helium: a density functional approach

We present a novel density functional for liquid 4He, properly accounting for the static response function and the phonon-roton dispersion in the uniform liquid. The functional is used to study both structural and dynamical properties of superfluid helium in various geometries. The equilibrium properties of the free surface, droplets and films at zero temperature are calculated. Our predictions agree closely to the results of ab initio Monte Carlo calculations, when available. The introduction of a phenomenological velocity dependent interaction, which accounts for backflow effects, is discussed. The spectrum of the elementary excitations of the free surface and films is studied.Comment: 37 pages, REVTeX 3.0, figures on request at [email protected]

Apathy Associated With Impaired Recognition of Happy Facial Expressions in Huntington's Disease.

OBJECTIVES: Previous research has demonstrated an association between emotion recognition and apathy in several neurological conditions involving fronto-striatal pathology, including Parkinson's disease and brain injury. In line with these findings, we aimed to determine whether apathetic participants with early Huntington's disease (HD) were more impaired on an emotion recognition task compared to non-apathetic participants and healthy controls. METHODS: We included 43 participants from the TRACK-HD study who reported apathy on the Problem Behaviours Assessment - short version (PBA-S), 67 participants who reported no apathy, and 107 controls matched for age, sex, and level of education. During their baseline TRACK-HD visit, participants completed a battery of cognitive and psychological tests including an emotion recognition task, the Hospital Depression and Anxiety Scale (HADS) and were assessed on the PBA-S. RESULTS: Compared to the non-apathetic group and the control group, the apathetic group were impaired on the recognition of happy facial expressions, after controlling for depression symptomology on the HADS and general disease progression (Unified Huntington's Disease Rating Scale total motor score). This was despite no difference between the apathetic and non-apathetic group on overall cognitive functioning assessed by a cognitive composite score. CONCLUSIONS: Impairment of the recognition of happy expressions may be part of the clinical picture of apathy in HD. While shared reliance on frontostriatal pathways may broadly explain associations between emotion recognition and apathy found across several patient groups, further work is needed to determine what relationships exist between recognition of specific emotions, distinct subtypes of apathy and underlying neuropathology. (JINS, 2019, 25, 453-461)

Assessing applicability when comparing medical interventions: AHRQ and the Effective Health Care Program

10.1016/j.jclinepi.2010.11.021Journal of Clinical Epidemiology64111198-1207JCEP

Outcomes after Ross procedure in adult patients: A meta-analysis and microsimulation

Objective We conducted a meta-analysis to estimate the risk of adverse events, life expectancy, and event-free life expectancy after the Ross procedure in adults. Methods We searched databases for reports evaluating the Ross procedure in patients aged more than or equal to 16 years of age. A microsimulation model was used to evaluate age- and gender-specific life expectancy for patients undergoing the Ross procedure. Results Data were pooled from 63 articles totaling 19 155 patients from 20 countries. Perioperative mortality was 2.5% (95% confidence interval [CI]: 1.9-3.1; N = 9978). We found a mortality risk of 5.9% (95% CI: 4.8-7.2) at a mean follow-up of 7.2 years (N = 7573). The rate of perioperative clinically significant bleeding was 1.0% (95% CI: 0.1-3.0); re-exploration for bleeding 4.6% (95% CI: 3.1-6.3); postoperative clinically significant bleeding from 30 days until a mean of 7.1 years was 0.5% (95% CI: 0.2-1.0). At a mean of 6.9 years of follow-up, reintervention rate of any operated valve was 7.9% (95% CI: 5.7-10.3). The risk of valve thrombosis was 0.3% (95% CI: 0.2-0.5) at 7.6 years; peripheral embolism 0.3% (95% CI: 0.2-0.4) at 6.4 years; stroke 0.9% (95% CI: 0.7-1.2) at 6.5 years; and endocarditis 2.1% (95% CI: 1.6-2.6) at 8.0 years. Microsimulation reported a 40-year-old undergoing the Ross procedure to have a life expectancy of 35.4 years and event-free life expectancy of 26.6 years. Conclusions Ross procedure in nonelderly adults is associated with low mortality and low risk of adverse events both at short- and long-term follow-up. The surgical community must prioritize a large, expertize-based randomized controlled trial to definitively address the risks and benefits of the Ross procedure compared to conventional aortic valve replacement.Thoracic Surger

Disambiguating pharmacological mechanisms from placebo in neuropathic pain using functional neuroimaging.

BACKGROUND A lack of objective outcome measures and overreliance on subjective pain reports in early proof-of-concept studies contribute to the high attrition of potentially effective new analgesics. We studied the utility of neuroimaging in providing objective evidence of neural activity related to drug modulation or a placebo effect in a double-blind, randomized, placebo-controlled, three-way crossover trial. METHODS We chronically administered pregabalin or tramadol (first-line and second-line analgesics, respectively), recommended for neuropathic pain, in 16 post-traumatic neuropathic pain patients. We measured subjective pain reports, allodynia-evoked neural activity, and brain resting state functional connectivity from patients during the three sessions and resting state data at baseline from patients after washout of their current medication. All data were collected using a 3 T MRI scanner. RESULTS When compared with placebo only, pregabalin significantly suppressed allodynia-evoked neural activity in several nociceptive and pain-processing areas of the brain, despite the absence of behavioural analgesia. Furthermore, placebo significantly increased functional connectivity between the rostral anterior cingulate and the brainstem, a core component of the placebo neural network. CONCLUSIONS Functional neuroimaging provided objective evidence of pharmacodynamic efficacy in a proof-of-concept study setting where subjective pain outcome measures are often unreliable. Additionally, we provide evidence confirming the neural mechanism underpinning placebo analgesia as identified in acute experimental imaging studies in patients during the placebo arm of a clinical trial. We explore how brain penetrant active drugs potentially interact with this mechanism. CLINICAL TRIAL REGISTRATION NCT0061015