Heat conduction of (111) Co/Cu superlattices

We report the observation of a large negative magnetothermal resistance in (111) Co/Cu superlattices grown by molecular beam epitaxy (MBE) techniques. The observed field dependence is proportional to that of the electrical resistance, in accordance with the Wiedemann–Franz law. The Lorentz number deduced from the measurements is (2.7±0.3)×10−8 V2/K2(2.7±0.3)×10−8V2/K2. The magnetothermopower also shows a similar correlation with resistivity. These findings reveal that large-angle elastic scattering of conduction electrons, arising from a spin-dependent density of states at the Fermi level, is the dominant process responsible for the observed large magnetotransport effects. In zero field, both electrons and phonons contribute to the thermal conduction of the MBE-grown Co/Cu system, at a ratio of about 1:2 near 300 K becoming nearly equal below 150 K. © 1997 American Institute of Physics.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/70031/2/JAPIAU-81-8-4586-1.pd

Elevated protein concentrations in newborn blood and the risks of autism spectrum disorder, and of social impairment, at age 10 years among infants born before the 28th week of gestation

Among the 1 of 10 children who are born preterm annually in the United States, 6% are born before the third trimester. Among children who survive birth before the 28th week of gestation, the risks of autism spectrum disorder (ASD) and non-autistic social impairment are severalfold higher than in the general population. We examined the relationship between top quartile inflammation-related protein concentrations among children born extremely preterm and ASD or, separately, a high score on the Social Responsiveness Scale (SRS total score ≥65) among those who did not meet ASD criteria, using information only from the subset of children whose DAS-II verbal or non-verbal IQ was ≥70, who were assessed for ASD, and who had proteins measured in blood collected on ≥2 days (N = 763). ASD (N = 36) assessed at age 10 years is associated with recurrent top quartile concentrations of inflammation-related proteins during the first post-natal month (e.g., SAA odds ratio (OR); 95% confidence interval (CI): 2.5; 1.2–5.3) and IL-6 (OR; 95% CI: 2.6; 1.03–6.4)). Top quartile concentrations of neurotrophic proteins appear to moderate the increased risk of ASD associated with repeated top quartile concentrations of inflammation-related proteins. High (top quartile) concentrations of SAA are associated with elevated risk of ASD (2.8; 1.2–6.7) when Ang-1 concentrations are below the top quartile, but not when Ang-1 concentrations are high (1.3; 0.3–5.8). Similarly, high concentrations of TNF-α are associated with heightened risk of SRS-defined social impairment (N = 130) (2.0; 1.1–3.8) when ANG-1 concentrations are not high, but not when ANG-1 concentrations are elevated (0.5; 0.1–4.2)

Genomic investigations of unexplained acute hepatitis in children

Since its first identification in Scotland, over 1,000 cases of unexplained paediatric hepatitis in children have been reported worldwide, including 278 cases in the UK1. Here we report an investigation of 38 cases, 66 age-matched immunocompetent controls and 21 immunocompromised comparator participants, using a combination of genomic, transcriptomic, proteomic and immunohistochemical methods. We detected high levels of adeno-associated virus 2 (AAV2) DNA in the liver, blood, plasma or stool from 27 of 28 cases. We found low levels of adenovirus (HAdV) and human herpesvirus 6B (HHV-6B) in 23 of 31 and 16 of 23, respectively, of the cases tested. By contrast, AAV2 was infrequently detected and at low titre in the blood or the liver from control children with HAdV, even when profoundly immunosuppressed. AAV2, HAdV and HHV-6 phylogeny excluded the emergence of novel strains in cases. Histological analyses of explanted livers showed enrichment for T cells and B lineage cells. Proteomic comparison of liver tissue from cases and healthy controls identified increased expression of HLA class 2, immunoglobulin variable regions and complement proteins. HAdV and AAV2 proteins were not detected in the livers. Instead, we identified AAV2 DNA complexes reflecting both HAdV-mediated and HHV-6B-mediated replication. We hypothesize that high levels of abnormal AAV2 replication products aided by HAdV and, in severe cases, HHV-6B may have triggered immune-mediated hepatic disease in genetically and immunologically predisposed children

Growth and annealing study of MBE-growth Rh(111) films.

We present a comprehensive study of the formation and evolution of homoepitaxial Rh(111) thin film surface morphology. This set of scanning tunneling microscopy (STM) and reflection high energy electron diffraction (RHEED) experiments is unique in terms of the combination of imaging and diffraction techniques and combining both growth and annealing in a single study. Rh(111) in many ways represents a model system for such studies in that it can be used to access a variety of growth regimes over a wide temperature range. A series of 10.1 monolayer (ML) Rh(111) films were grown via molecular beam epitaxy (MBE) at temperatures ranging from 375K to 875K. These surfaces show three distinct growth regimes, low temperature 3D growth, a mid-range (500K-700K) extended 2D layer-by-layer growth regime, and high temperature 3D growth. Both the high and low temperature 3D regimes exhibit patterned surfaces with well-defined feature separation (R), illustrating that they cannot be classified as self-affine. As growth proceeds, R increases following a power-law dependence on film thickness with a morphology-independent exponent of 0.33 $\pm$ 0.03. We observe a morphological transition in nucleation and growth at 600K. STM images of Rh(111) surfaces show fingered step edges for 10.1 ML films grown below 600K and compact features for higher temperature growth. Submononlayer deposition studies indicate that dimers become unstable at temperatures above 600K, with the binding energy of dimers set at 0.6 $\pm$ 0.4 eV. These results highlight the effect of one-bond detachment on the overall growth kinetics on the Rh(111) surface. Finally, we utilize the power of in-situ RHEED analysis to study the equilibrium-bound smoothing kinetics of 2D and 3D Rh(111) surface features during annealing. The 2D islands coarsen rapidly throughout the anneal. The 3D features are more stable initially, and then flatten rapidly. The transition activation energy is $\sim$0.6 eV, which corresponds to the one-bond detachment energy discussed above. These findings suggest that the smoothing kinetics of 3D features is limited by adatom detachment at low temperatures, with faster processes activated at higher temperatures to facilitate rapid smoothing. The results provide a roadmap for achieving smooth layer-by-layer growth in close-packed metals.Ph.D.Condensed matter physicsPure SciencesUniversity of Michigan, Horace H. Rackham School of Graduate Studieshttp://deepblue.lib.umich.edu/bitstream/2027.42/131128/2/9825375.pd

Implementation of a Comprehensive Tobacco-Cessation Policy in Medicaid Managed Care Plans in California.

IntroductionIn 2016, the California Department of Health Care Services issued All Plan Letter 16-014 to the Medi-Cal Managed Care plans to provide information on requirements for comprehensive tobacco-cessation services. Researchers at the University of California, San Diego set out to (1) examine Medi-Cal's Managed Care plans' progress in implementing each section of All Plan Letter 16-014, (2) understand various factors related to implementation of the All Plan Letter, and (3) make recommendations to improve implementation.MethodsResearchers surveyed health educators within California's 25 Medi-Cal Managed Care plans to document each one's smoking-cessation services and policies in 2018. Data were collected for 24 of the 25 Medi-Cal Managed Care plans (96%) through 3 methods, including: (1) a web-based survey, (2) an in-depth phone interview, and (3) collection of smoking cessation-relevant documents.ResultsManaged Care plans demonstrate low levels of full implementation, with only 1 fully implementing all 20 provisions of the All Plan Letter. On average, Managed Care plans implemented 13 of the 20 provisions. Managed Care plans had the highest implementation rates for provisions related to requirements for coverage of the 7 U.S. Food and Drug Administration-approved medications for tobacco cessation, in which 12 (55%) fully implemented all related required provisions. Managed Care plans had lowest implementation rates for provisions related to data collection, with only 4 (18%) fully implementing all 3 requirements.ConclusionsAlthough All Plan Letter 16-014 was successful in creating more comprehensive and consistent benefits across Managed Care plans, 95% of Managed Care plans have not fully implemented it. Further guidance from the Department of Health Care Services and integration with the California Smokers' Helpline may be needed to achieve full implementation