Ensemble Concerts: Wind Symphony, April 25, 2010

Center for the Performing ArtsSunday AfternoonApril 25, 20103:00 p.m

Group and individual change in cognitive functioning in patients with 1 to 10 brain metastases following Gamma Knife radiosurgery

Aims:  Stereotactic radiosurgery is increasingly used to treat multiple (four or more) brain metastases. Preserving cognitive functions is a highly relevant treatment goal because cognitive deteriorations may negatively affect a patient's quality of life. The aim of this study was to assess cognitive change, at the group and individual level, in patients with 1 to 10 brain metastases up to 9 months after Gamma Knife radiosurgery (GKRS). Materials and methods:  Ninety-two patients with 1 to 10 newly diagnosed brain metastases, expected survival >3 months and Karnofsky Performance Status (KPS) ≥70 and 104 non-cancer controls were included. A neuropsychological test battery was administered before GKRS (n = 92) and at 3 (n = 66), 6 (n = 52) and 9 (n = 41) months after GKRS. The course of test performances, while taking into account practice effects, was analysed using linear mixed models. Pre-GKRS predictors of cognitive trajectories were analysed. To determine proportions of individuals with cognitive changes, reliable change indices, with correction for practice effects, were calculated. Results:  At the group level, immediate memory, working memory and information processing speed significantly improved over 9 months after GKRS. There were no cognitive declines. Neither number nor volume of brain metastases influenced cognitive change over time. At the individual level, proportions of patients with stable, improved or declined performances were comparable with controls, except for information processing speed (more individuals with improvements in patients) and motor dexterity (more improvements and declines in patients). Conclusions:  Cognitive functioning in patients with 1 to 10 brain metastases was preserved, or improved, up to 9 months after GKRS. Neither number nor volume of brain metastases influenced cognitive performance

The role of defects in fluorescent silicon carbide layers grown by sublimation epitaxy

Donor-acceptor co-doped SiC is a promising light converter for novel monolithic all-semiconductor white LEDs due to its broad-band donor-acceptor pair luminescence and potentially high internal quantum efficiency. Besides sufficiently high doping concentrations in an appropriate ratio yielding short radiative lifetimes, long nonradiative lifetimes are crucial for efficient light conversion. The impact of different types of defects is studied by characterizing fluorescent silicon carbide layers with regard to photoluminescence intensity, homogeneity and efficiency taking into account dislocation density and distribution. Different doping concentrations and variations in gas phase composition and pressure are investigated

Measurement of mechanical vibrations excited in aluminium resonators by 0.6 GeV electrons

We present measurements of mechanical vibrations induced by 0.6 GeV electrons impinging on cylindrical and spherical aluminium resonators. To monitor the amplitude of the resonator's vibrational modes we used piezoelectric ceramic sensors, calibrated by standard accelerometers. Calculations using the thermo-acoustic conversion model, agree well with the experimental data, as demonstrated by the specific variation of the excitation strengths with the absorbed energy, and with the traversing particles' track positions. For the first longitudinal mode of the cylindrical resonator we measured a conversion factor of 7.4 +- 1.4 nm/J, confirming the model value of 10 nm/J. Also, for the spherical resonator, we found the model values for the L=2 and L=1 mode amplitudes to be consistent with our measurement. We thus have confirmed the applicability of the model, and we note that calculations based on the model have shown that next generation resonant mass gravitational wave detectors can only be expected to reach their intended ultra high sensitivity if they will be shielded by an appreciable amount of rock, where a veto detector can reduce the background of remaining impinging cosmic rays effectively.Comment: Tex-Article with epsfile, 34 pages including 13 figures and 5 tables. To be published in Rev. Scient. Instr., May 200

Bariatric surgery improves postprandial VLDL kinetics and restores insulin mediated regulation of hepatic VLDL production

Dyslipidemia in obesity results from excessive production and impaired clearance of triglyceride-rich (TG-rich) lipoproteins, which are particularly pronounced in the postprandial state. Here, we investigated the impact of Roux-en-Y gastric bypass (RYGB) surgery on postprandial VLDL1 and VLDL2 apoB and TG kinetics and their relationship with insulin-responsiveness indices. Morbidly obese patients without diabetes who were scheduled for RYGB surgery (n = 24) underwent a lipoprotein kinetics study during a mixed-meal test and a hyperinsulinemic-euglycemic clamp study before the surgery and 1 year later. A physiologically based computational model was developed to investigate the impact of RYGB surgery and plasma insulin on postprandial VLDL kinetics. After the surgery, VLDL1 apoB and TG production rates were significantly decreased, whereas VLDL2 apoB and TG production rates remained unchanged. The TG catabolic rate was increased in both VLDL1 and VLDL2 fractions, but only the VLDL2 apoB catabolic rate tended to increase. Furthermore, postsurgery VLDL1 apoB and TG production rates, but not those of VLDL2, were positively correlated with insulin resistance. Insulin-mediated stimulation of peripheral lipoprotein lipolysis was also improved after the surgery. In summary, RYGB resulted in reduced hepatic VLDL1 production that correlated with reduced insulin resistance, elevated VLDL2 clearance, and improved insulin sensitivity in lipoprotein lipolysis pathways.</p

Association of Aortic Stiffness With Biomarkers of Neuroinflammation, Synaptic Dysfunction, and Neurodegeneration

OBJECTIVES: To test the hypothesis that increased aortic stiffening is associated with greater cerebrospinal fluid (CSF) evidence of core Alzheimer's disease pathology (Aβ, phosphorylated tau (p-tau)), neurodegeneration (total tau (t-tau)), synaptic dysfunction (neurogranin), neuroaxonal injury (neurofilament light (NFL)), and neuroinflammation (YKL-40, sTREM2), we analyzed pulse wave velocity (PWV) data and CSF data among older adults. METHODS: Participants free of stroke and dementia from the Vanderbilt Memory and Aging Project, an observational community-based study, underwent cardiac magnetic resonance to assess aortic pulse wave velocity (PWV, m/sec) and lumbar puncture to obtain CSF. Linear regressions related aortic PWV to CSF Aβ, p-tau, t-tau, neurogranin, NFL, YKL-40, and sTREM2 concentrations adjusting for age, race/ethnicity, education, apolipoprotein (APOE) ε4 status, Framingham Stroke Risk Profile, and cognitive diagnosis. Models were repeated testing PWV interactions with age, diagnosis, APOE-ε4, and hypertension on each biomarker. RESULTS: 146 participants were examined (72±6 years). Aortic PWV interacted with age on p-tau (β=0.31, p=0.04), t-tau, (β=2.67, p=0.05), neurogranin (β=0.94, p=0.04), and sTREM2 (β=20.4, p=0.05). Among participants over age 73 years, higher aortic PWV related to higher p-tau (β=2.4, p=0.03), t-tau (β=19.3, p=0.05), neurogranin (β=8.4, p=0.01), and YKL-40 concentrations (β=7880, p=0.005). Aortic PWV had modest interactions with diagnosis on neurogranin (β=-10.76, p=0.03) and hypertension status on YKL-40 (β=-18020, p<0.001). CONCLUSIONS: Among our oldest participants, age 74 years and older, greater aortic stiffening is associated with in vivo biomarker evidence of neuroinflammation, tau phosphorylation, synaptic dysfunction, and neurodegeneration, but not amyloidosis. Central arterial stiffening may lead to cumulative cerebral microcirculatory damage and blood flow delivery to tissue, resulting in neuroinflammation and neurodegeneration in more advanced age

Psychedelics for existential distress in terminally ill patients

BACKGROUND: Existential distress in patients with a terminal illness is often associated with (symptoms of) anxiety and depression. Psychotherapeutic interventions seem effective but effects are short-lived. There are no proven effective pharmacological interventions.&lt;br/&gt; AIM: To present an overview of literature on psychedelic treatment of existential distress in patients with terminal illness.&lt;br/&gt; METHOD: Literature research in PubMed/Medline databases, supplemented with cross-references.&lt;br/&gt; RESULTS: 14 clinical studies have been conducted: 6 with classic psychedelics between 1960 and 1980, and 8 with classic psychedelics and ketamine after 2000. Results of early pre-post studies are promising but have serious methodological limitations. Recent clinical research with LSD, psilocybin and ketamine are also promising although limited in terms of research design and generalizability. Overall, studies show a positive effect on existential and spiritual well-being, quality of life, acceptance and (symptoms of) anxiety and depression. Mystical experiences are correlated with positive outcomes. Few adverse effects are reported.&lt;br/&gt; CONCLUSION: Treatment of existential distress using classical psychedelics or ketamine in patients with terminal illness seems auspicious. Larger clinical studies in a more diverse patient population with fewer methodological limitations are needed to draw conclusions about efficacy and generalizability.</p

The tailings dam failure of 5 November 2015 in SE Brazil and its preceding seismic sequence

The collapse of a mine tailings dam and subsequent flood in SE Brazil on 5 November 2015 was preceded by a small-magnitude seismic sequence. In this report, we explore the spatiotemporal associations between the seismic events and the accident and discuss their possible connection. We also analyze the signals generated by the turbulent mudflow, as recorded by the Brazilian Seismographic Network (RSBR). In light of our observations, we propose as possible contributing factor for the dam collapse either ground shaking and/or soil liquefaction triggered by the earthquakes. The possibility of such a small-magnitude earthquake contributing to the collapse of a tailings dam raises important concerns regarding safety and related legislation of dams in Brazil and the world. ©2016. American Geophysical Union.H.A.D. and M.A. acknowledge support from Sao Paulo Research Foundation FAPESP grant 2014/09455-3 and CNPq grant 30.6547/2013-9.Peer reviewe