Effect of Gender on Atrial Electrophysiologic Changes Induced by Rapid Atrial Pacing and Elevation of Atrial Pressure

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/74798/1/j.1540-8167.2001.00986.x.pd

Effects of Simultaneous Atrioventricular Pacing on Atrial Refractoriness and Atrial Fibrillation Inducibility: Role of Atrial Mechanoelectrical Feedback

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/74794/1/j.1540-8167.2001.00043.x.pd

Tackling clinical heterogeneity across the Amyotrophic Lateral Sclerosis-Frontotemporal Dementia spectrum using a transdiagnostic approach

The disease syndromes of amyotrophic lateral sclerosis and frontotemporal dementia display considerable clinical, genetic and pathological overlap, yet mounting evidence indicates substantial differences in progression and survival. To date, there has been limited examination of how profiles of brain atrophy might differ between clinical phenotypes. Here, we address this longstanding gap in the literature by assessing cortical and subcortical grey and white matter volumes on structural MRI in a large cohort of 209 participants. Cognitive and behavioural changes were assessed using the Addenbrooke’s Cognitive Examination and the Cambridge Behavioural Inventory. Relative to 58 controls, behavioural variant frontotemporal dementia (n = 58) and amyotrophic lateral sclerosis-frontotemporal dementia (n = 41) patients displayed extensive atrophy of frontoinsular, cingulate, temporal and motor cortices, with marked subcortical atrophy targeting the hippocampus, amygdala, thalamus, and striatum, with atrophy further extended to the brainstem, pons and cerebellum in the latter group. At the other end of the spectrum, pure-amyotrophic lateral sclerosis patients (n = 52) displayed considerable frontoparietal atrophy, including right insular and motor cortices and pons and brainstem regions. Subcortical regions included the bilateral pallidum and putamen, but to a lesser degree than in the amyotrophic lateral sclerosis-frontotemporal dementia and behavioural variant frontotemporal dementia groups. Across the spectrum the most affected region in all three groups was the insula, and specifically the anterior part (76-90% lower than controls). Direct comparison of the patient groups revealed disproportionate temporal atrophy and widespread subcortical involvement in amyotrophic lateral sclerosis-frontotemporal dementia relative to pure-amyotrophic lateral sclerosis. In contrast, pure-amyotrophic lateral sclerosis displayed significantly greater parietal atrophy. Both behavioural variant frontotemporal dementia and amyotrophic lateral sclerosis-frontotemporal dementia were characterised by volume decrease in the frontal lobes relative to pure-amyotrophic lateral sclerosis. The motor cortex and insula emerged as differentiating structures between clinical syndromes, with bilateral motor cortex atrophy more pronounced in amyotrophic lateral sclerosis-frontotemporal dementia compared to pure-amyotrophic lateral sclerosis, and greater left motor cortex and insula atrophy relative to behavioural variant frontotemporal dementia. Taking a transdiagnostic approach, we found significant associations between abnormal behaviour and volume loss in a predominantly frontoinsular network involving the amygdala, striatum and thalamus. Our findings demonstrate the presence of distinct atrophy profiles across the amyotrophic lateral sclerosis-frontotemporal dementia spectrum, with key structures including the motor cortex and insula, Notably, our results point to subcortical involvement in the origin of behavioural disturbances, potentially accounting for the marked phenotypic variability typically observed across the spectrum

Prevalence and significance of Exit Block During Arrhythmias Arising in Pulmonary Veins

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/74819/1/j.1540-8167.2000.tb00332.x.pd

Multimodeling, Singular Perturbations and Chained Aggregation of Large Scale Systems

Coordinated Science Laboratory was formerly known as Control Systems LaboratoryDepartment of Energy / US ERDA EX-76-C-01-208

Active smoking and survival following breast cancer among African American and non-African American women in the Carolina Breast Cancer Study

Purpose: To examine racial differences in smoking rates at the time of breast cancer diagnosis and subsequent survival among African American and non-African American women in the Carolina Breast Cancer Study (Phases I/II), a large population-based North Carolina study. Methods: We interviewed 788 African American and 1,020 Caucasian/non-African American women diagnosed with invasive breast cancer from 1993 to 2000, to assess smoking history. After a median follow-up of 13.56 years, we identified 717 deaths using the National Death Index; 427 were breast cancer-related. We used Cox regression to examine associations between self-reported measures of smoking and breast cancer-specific survival within 5 years and up to 18 years after diagnosis conditional on 5-year survival. We examined race and estrogen receptor status as potential modifiers. Results: Current (vs never) smoking was not associated with 5-year survival; however, risk of 13 year conditional breast cancer-specific mortality was elevated among women who were current smokers at diagnosis (HR 1.54, 95% CI 1.06–2.25), compared to never smokers. Although smoking rates were similar among African American (22.0%) and non-African American (22.1%) women, risk of breast cancer-specific mortality was elevated among African American (HR 1.69, 95% CI 1.00–2.85), but only weakly elevated among non-African American (HR 1.22, 95% CI 0.70–2.14) current (vs. never) smokers (PInteraction = 0.30). Risk of breast cancer-specific mortality was also elevated among current (vs never) smokers diagnosed with ER− (HR 2.58, 95% CI 1.35–4.93), but not ER+ (HR 1.11, 95% CI 0.69–1.78) tumors (PInteraction = 0.17). Conclusions: Smoking may negatively impact long-term survival following breast cancer. Racial differences in long-term survival, as related to smoking, may be driven by ER status, rather than by differences in smoking patterns

Plasma levels of dichlorodiphenyldichloroethene (DDE) and dichlorodiphenyltrichloroethane (DDT) and survival following breast cancer in the Carolina Breast Cancer Study

Objectives: To examine plasma levels of dichlorodiphenyldichloroethene (DDE) and dichlorodiphenyltrichloroethane (DDT) in association with survival among women with breast cancer who participated in a population-based case-control study. Methods: Participants included 456 white and 292 black women from the Carolina Breast Cancer Study Phase I who were diagnosed with primary invasive breast cancer from 1993 to 1996, and who had available DDE/DDT and lipid measurements from blood samples obtained on average 4.1 months after diagnosis. Using the National Death Index, we identified 392 deaths (210 from breast cancer) over a median follow-up of 20.6 years. We used Cox regression to estimate covariate-adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) for all-cause and breast cancer-specific 5-year mortality, and 20-year mortality conditional on 5-year survival, for lipid-standardized DDE and DDT levels. Associations stratified by race and estrogen receptor (ER) status were also examined. Results: The highest versus lowest DDE tertile and the highest vs non-detectable DDT quantile were associated with HRs of 1.95 (95% CI = 1.31–2.92) and 1.64 (95% CI = 1.10–2.44), respectively, for 20-year conditional all-cause mortality. DDE levels above versus below the median were associated with a HR of 1.69 (95% CI = 1.06–2.68) for 20-year conditional breast cancer-specific mortality among women overall, and HRs were 2.36 (95% CI = 1.03–5.42) among black women and 1.57 (95% CI = 0.86–2.89) among white women (PInteraction = 0.42), and 3.24 (95% CI = 1.38–7.58) among women with ER− tumors and 1.29 (95% CI = 0.73–2.28) among women with ER+ tumors (PInteraction = 0.03). Conclusion: Exposure to DDE/DDT may adversely impact overall and breast cancer-specific survival. DDE exposure may contribute to the racial disparities in breast cancer survival

Plasma levels of polychlorinated biphenyls (PCBs) and breast cancer mortality: The Carolina Breast Cancer Study

Background: It is unknown whether carcinogenic and endocrine disrupting polychlorinated biphenyls (PCBs) influence mortality following breast cancer. We examined plasma levels of 17 PCB congeners in association with mortality among women with breast cancer. Methods: Participants included 456 white and 292 black women in North Carolina who were diagnosed with primary invasive breast cancer from 1993 to 1996, and who had PCB and lipid measurements from blood samples obtained an average of 4.1 months after diagnosis. Over a median follow-up of 20.6 years, there were 392 deaths (210 from breast cancer). We used Cox regression to estimate covariate-adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) for all-cause and breast cancer-specific 5-year mortality, and 20-year mortality (conditional on 5-year survival) in association with tertiles and continuous ln-transformed lipid-adjusted PCB levels. Results: The highest (vs. lowest) tertiles of PCB74, PCB99, and PCB118 were associated with 5-year breast cancer-specific mortality HRs of 1.46 (95%CI = 0.86–2.47), 1.57 (95%CI = 0.90–2.73), and 1.86 (95%CI = 1.07–3.23), respectively. Additionally, one-ln unit increases in PCB74, PCB99, PCB118, and total PCBs were each associated with 33–40% increases in 5-year breast cancer-specific mortality rates. The PCBs were not, however, associated with longer-term breast cancer-specific mortality. For all-cause mortality, one-ln unit increases in PCB118, PCB146, PCB153, PCB182, PCB187, and total PCBs were associated with 20–37% increases in 20-year all-cause mortality rates among women who survived at least 5 years. Conclusion: PCBs may increase the risk of short-term breast cancer-specific mortality and long-term all-cause mortality among women with breast cancer

Dual-gated bilayer graphene hot electron bolometer

Detection of infrared light is central to diverse applications in security, medicine, astronomy, materials science, and biology. Often different materials and detection mechanisms are employed to optimize performance in different spectral ranges. Graphene is a unique material with strong, nearly frequency-independent light-matter interaction from far infrared to ultraviolet, with potential for broadband photonics applications. Moreover, graphene's small electron-phonon coupling suggests that hot-electron effects may be exploited at relatively high temperatures for fast and highly sensitive detectors in which light energy heats only the small-specific-heat electronic system. Here we demonstrate such a hot-electron bolometer using bilayer graphene that is dual-gated to create a tunable bandgap and electron-temperature-dependent conductivity. The measured large electron-phonon heat resistance is in good agreement with theoretical estimates in magnitude and temperature dependence, and enables our graphene bolometer operating at a temperature of 5 K to have a low noise equivalent power (33 fW/Hz1/2). We employ a pump-probe technique to directly measure the intrinsic speed of our device, >1 GHz at 10 K.Comment: 5 figure

Dynamic nuclear polarization and spin-diffusion in non-conducting solids

There has been much renewed interest in dynamic nuclear polarization (DNP), particularly in the context of solid state biomolecular NMR and more recently dissolution DNP techniques for liquids. This paper reviews the role of spin diffusion in polarizing nuclear spins and discusses the role of the spin diffusion barrier, before going on to discuss some recent results.Comment: submitted to Applied Magnetic Resonance. The article should appear in a special issue that is being published in connection with the DNP Symposium help in Nottingham in August 200