Valence-electron transfer and a metal-insulator transition in a strongly correlated perovskite oxide

We present transport and thermal data for the quadruple-perovskites MCu3(Ti1-xRux)4O12 where 0 < x < 1. A metal-insulator transition (MIT) occurs for Ru concentrations x~0.75. At the same time, the Cu2+ antiferromagnetic state is destroyed and it's magnetic entropy suppressed by Ru on a 1:1 basis. This implies that each Ru transfers an electron to a Cu ion and thus the MIT correlates with filling the Cu 3d shell. The Cu spin entropy in this strongly correlated electron material provides a unique probe among MIT systems.Comment: 15 pages, 4 figures, 1 tabl

Sociodemographic and clinical characteristics of persons who experienced spontaneous hepatitis C viral clearance.

BackgroundIn the United States Hepatitis C virus (HCV) viral clearance is estimated to range between 20 and 30%. The objective of this study was to estimate the frequency of HCV clearance and identify correlates of viral clearance among patients newly identified as HCV antibody positive in a large urban health system in Los Angeles, California.MethodsWe identified patients between November 2015 and September 2017 as part of a newly implemented HCV screening and linkage-to-care program at University of California Los Angeles (UCLA) Health System. All patients were eligible for screening, though there were additional efforts to screen patients born between 1945 and 1965. We reviewed Medical records to categorize anti-HCV antibody positive patients as having spontaneously cleared HCV infection (HCV RNA not detected) or not (HCV RNA detected). We excluded those with a prior history of anti-HCV positivity or history of HCV treatment. We compared differences between those with and without detectable HCV RNA using chi-square test, Fisher's exact test, and t-test as appropriate. We assessed factors associated with HCV clearance using logistic regression analysis.ResultsAmong the 320 patients included in this study, 56% were male. Baby boomers (52-72 years of age) comprised the single largest age group (62%). We found spontaneous HCV clearance in 58% (n = 185). HCV viral clearance was slightly higher among women as compared to men (63% vs. 53%; p value = 0.07) and varied by race/ethnicity: clearance among Blacks/African Americans was 37% vs. 58% among whites (p value = 0.02). After adjusting for age, race/ethnicity, and sex we found that those diagnosed with chronic kidney disease had a tendency of decreased HCV viral clearance (adjusted OR = 0.34; 95% CI 0.14-1.03).ConclusionOf those patients newly identified as anti-HCV positive, 58% had cleared HCV virus, while the rest showed evidence of active infection. In addition, we found that clearance varied by race/ethnicity and clinical characteristics

Lattice dielectric response of CdCu{3}Ti{4}O{12} and of CaCu{3}Ti{4}O{12} from first principles

Structural, vibrational, and lattice dielectric properties of CdCu{3}Ti{4}O{12} are studied using density-functional theory within the local spin-density approximation, and the results are compared with those computed previously for CaCu{3}Ti{4}O{12}. Replacing Ca with Cd is found to leave many calculated quantities largely unaltered, although significant differences do emerge in zone-center optical phonon frequencies and mode effective charges. The computed phonon frequencies of CdCu{3}Ti{4}O{12} are found to be in excellent agreement with experiment, and the computed lattice contribution to the intrinsic static dielectric constant (~60) also agrees exceptionally well with a recent optical absorption experiment. These results provide further support for a picture in which the lattice dielectric response is essentially conventional, suggesting an extrinsic origin for the anomalous low-frequency dielectric response recently observed in both materials.Comment: 5 pages; uses REVTEX macros. Also available at http://www.physics.rutgers.edu/~dhv/preprints/lh_cdct/index.htm

Coupling between electronic and structural degrees of freedom in the triangular lattice conductor NaxCoO2

The determination by powder neutron diffraction of the ambient temperature crystal structures of compounds in the NaxCoO2 family, for 0.3 < x <= 1.0, is reported. The structures consist of triangular CoO2 layers with Na ions distributed in intervening charge reservoir layers. The shapes of the CoO6 octahedra that make up the CoO2 layers are found to be critically dependent on the electron count and on the distribution of the Na ions in the intervening layers, where two types of Na sites are available. Correlation of the shapes of cobalt-oxygen octahedra, the Na ion positions, and the electronic phase diagram in NaxCoO2 is made, showing how structural and electronic degrees of freedom can be coupled in electrically conducting triangular lattice systems.Comment: 15 pages, 1 tables, 6 figures Submitted to Physical Review

Juntos y Saludables: Outcomes of a peer led approach to obesity prevention for Head Start

Purpose: The purpose of this study was to evaluate Juntos y Saludables (Get Healthy Together), a multi-component obesity prevention pilot tailored for Mexican American Head Start children (ages 3-5). For the parent education component, researchers trained seven peer parent educators to deliver health information via afterschool parent education sessions. When parents attended the sessions, they received a take-home bag with a book and family activity to promote physical activity in the home. Method: Parent intercept interviews, focus groups, and questionnaires were collected (average 80% participation rate). Results: Average participation rate at the parent education sessions was 46% and rates varied between 34% (61 parents) and 53% (94 parents). More parents in the intervention school reported that their child ate fruit at least 3 times (83.5% versus 79.17%), ate in front of the television less than three times (70.87% versus 49.38%) during the typical week and more parents reported that their child watched 2 hours or less of television each day (73.79% versus 13.19%), compared to the comparison school. 81% of parents interviewed correctly identified the program name. On average, parents could recall almost 3 (M=2.94, SD=1.92) of the 8 key messages without a prompt and about 6 (M=5.91, SD=1.88) when prompted. Messages recalled the most, without a prompt, included (1) preschoolers need 60 minutes of physical activity each day, and (2) children who get all five servings of fruits and vegetables each day are more likely to get the nutrients they need. In the focus group, parents reported that they enjoyed the peer-led session format and session scheduled time. Conclusion: Results suggest that peer-led approaches can be highly effective with parents, especially when addressing childhood obesity prevention

Lessons Learned from Juntos Y Saludables Peer-Led Parent Education

Purpose: The objective of this study was to assess the quality of training received by peer educators in the Juntos y Saludables (Get Healthy Together) program. Juntos y Saludables is a multi-component childhood obesity prevention program for Head Start. Method: This study applied the peer led education approach to provide parents with education regarding healthy growth among their children. Seven parents were recruited through teachers, other parents, and the Parent Leadership Institute at a local Head Start center. Faculty and graduate assistants from local universities provided training to the parent educators in both English and Spanish. Training sessions were conducted the week of each new parent education session, with one booster training after spring break (7 training sessions in total). The parent educators were trained to: (1) encourage the Head Start parents to participate in the sessions, (2) explain the health messages, and (3) answer any questions the parents had. A focus group was conducted at the end of the program, with all seven parent educators, to assess their feedback about the training they received. Results: The peer parent educators reported that they became educators to improve children’s health. They were satisfied with the training methods and felt that they learned a lot of information regarding nutrition and physical activity recommendations for their children. They also reported feeling comfortable delivering health information to other parents. Parent educators appreciated that they could work together (e.g., in bilingual pairs) to provide the health education to parents in both English and Spanish. The peer parent education training session attendance was high-71% and greater. Conclusions: Most peer parent educators felt comfortable and confident delivering the material as the program progressed. Earlier training might assist the parent educators to have greater familiarity with content prior to the first session. Educators also created strategies to deal with situations that arose during the sessions (e.g. crowd control, parents requesting extra bags). Future training can include suggested strategies to handle similar situations

Nonmonotonic Temperature-dependent Resistance in Low Density 2D Hole Gases

The low temperature longitudinal resistance-per-square Rxx(T) in ungated GaAs/AlGaAs quantum wells of high peak hole mobility 1.7x10^6 cm^2/Vs is metallic for 2D hole density p as low as 3.8x10^9 cm-2. The electronic contribution to the resistance, R_{el}(T), is a nonmonotonic function of T, exhibiting thermal activation, R_{el}(T) ~ exp{-E_a/kT}, for kT<<E_F and a heretofore unnoted decay R_{el}(T) ~ 1/T for k_T>EF. The form of R_{el}(T) is independent of density, indicating a fundamental relationship between the low and high T scattering mechanisms in the metallic state

Anomalous magnetic response of the spin-one-half Falicov-Kimball model

The infinite-dimensional spin one-half Falicov-Kimball model in an external magnetic field is solved exactly. We calculate the magnetic susceptibility in zero field, and the magnetization as a function of the field strength. The model shows an anomalous magnetic response from thermally excited local moments that disappear as the temperature is lowered. We describe possible real materials that may exhibit this kind of anomalous behavior.Comment: 17 pages, 6 encapsulated postscript figures (included), submitted to Phys. Rev.

MicroRNA-223 ameliorates alcoholic liver injury by inhibiting the IL-6–p47phox–oxidative stress pathway in neutrophils

Objectives Chronic-plus-binge ethanol feeding activates neutrophils and exacerbates liver injury in mice. This study investigates how recent excessive drinking affects peripheral neutrophils and liver injury in alcoholics, and how miR-223, one of the most abundant microRNAs (miRNAs) in neutrophils, modulates neutrophil function and liver injury in ethanol-fed mice. Designs Three hundred alcoholics with (n=140) or without (n=160) recent excessive drinking and 45 healthy controls were enrolled. Mice were fed an ethanol diet for 10 days followed by a single binge of ethanol. Results Compared with healthy controls or alcoholics without recent drinking, alcoholics with recent excessive drinking had higher levels of circulating neutrophils, which correlated with serum levels of alanine transaminase (ALT) and aspartate transaminase (AST). miRNA array analysis revealed that alcoholics had elevated serum miR-223 levels compared with healthy controls. In chronic-plus-binge ethanol feeding mouse model, the levels of miR-223 were increased in both serum and neutrophils. Genetic deletion of the miR-223 gene exacerbated ethanol-induced hepatic injury, neutrophil infiltration, reactive oxygen species (ROS) and upregulated hepatic expression of interleukin (IL)-6 and phagocytic oxidase (phox) p47phox. Mechanistic studies revealed that miR-223 directly inhibited IL-6 expression and subsequently inhibited p47phox expression in neutrophils. Deletion of the p47phox gene ameliorated ethanol-induced liver injury and ROS production by neutrophils. Finally, miR-223 expression was downregulated, while IL-6 and p47phox expression were upregulated in peripheral blood neutrophils from alcoholics compared with healthy controls. Conclusions miR-223 is an important regulator to block neutrophil infiltration in alcoholic liver disease and could be a novel therapeutic target for the treatment of this malady