Self-consistent Overhauser model for the pair distribution function of an electron gas in dimensionalities D=3 and D=2

We present self-consistent calculations of the spin-averaged pair distribution function $g(r)$ for a homogeneous electron gas in the paramagnetic state in both three and two dimensions, based on an extension of a model that was originally proposed by A. W. Overhauser [Can. J. Phys. {\bf 73}, 683 (1995)] and further evaluated by P. Gori-Giorgi and J. P. Perdew [Phys. Rev. B {\bf 64}, 155102 (2001)]. The model involves the solution of a two-electron scattering problem via an effective Coulombic potential, that we determine within a self-consistent Hartree approximation. We find numerical results for $g(r)$ that are in excellent agreement with Quantum Monte Carlo data at low and intermediate coupling strength $r_s$, extending up to $r_s\approx 10$ in dimensionality D=3. However, the Hartree approximation does not properly account for the emergence of a first-neighbor peak at stronger coupling, such as at $r_s=5$ in D=2, and has limited accuracy in regard to the spin-resolved components $g_{\uparrow\uparrow}(r)$ and $g_{\uparrow\downarrow}(r)$. We also report calculations of the electron-electron s-wave scattering length, to test an analytical expression proposed by Overhauser in D=3 and to present new results in D=2 at moderate coupling strength. Finally, we indicate how this approach can be extended to evaluate the pair distribution functions in inhomogeneous electron systems and hence to obtain improved exchange-correlation energy functionals.Comment: 14 pages, 7 figuers, to apear in Physical Review

Electronic resonance states in metallic nanowires during the breaking process simulated with the ultimate jellium model

We investigate the elongation and breaking process of metallic nanowires using the ultimate jellium model in self-consistent density-functional calculations of the electron structure. In this model the positive background charge deforms to follow the electron density and the energy minimization determines the shape of the system. However, we restrict the shape of the wires by assuming rotational invariance about the wire axis. First we study the stability of infinite wires and show that the quantum mechanical shell-structure stabilizes the uniform cylindrical geometry at given magic radii. Next, we focus on finite nanowires supported by leads modeled by freezing the shape of a uniform wire outside the constriction volume. We calculate the conductance during the elongation process using the adiabatic approximation and the WKB transmission formula. We also observe the correlated oscillations of the elongation force. In different stages of the elongation process two kinds of electronic structures appear: one with extended states throughout the wire and one with an atom-cluster like unit in the constriction and with well localized states. We discuss the origin of these structures.Comment: 11 pages, 8 figure

Characterization of lymphocyte populations in nonspecific interstitial pneumonia*

STUDY OBJECTIVES: Nonspecific interstitial pneumonia (NSIP) has been identified as a distinct entity with a more favorable prognosis and better response to immunosuppressive therapies than usual interstitial pneumonia (UIP). However the inflammatory profile of NSIP has not been characterized. DESIGN: Using immunohistochemistry techniques on open lung biopsy specimens, the infiltrate in NSIP was characterized in terms of T and B cells, and macrophages, and the T cell population further identified as either CD4 (helper) or CD8 (suppressor-cytotoxic) T cells. The extent of Th1 and Th2 cytokine producing cells was determined and compared to specimens from patients with UIP. RESULTS: In ten NSIP tissue samples 41.4 ± 4% of mononuclear cells expressed CD3, 24.7 ± 1.8% CD4, 19.1 ± 2% CD8, 27.4 ± 3.9% CD20, and 14.3 ± 1.6% had CD68 expression. Mononuclear cells expressed INFγ 21.9 ± 1.9% of the time and IL-4 in 3.0 ± 1%. In contrast, biopsies from eight patients with UIP demonstrated substantially less cellular staining for either cytokine (INFγ; 4.6 ± 1.7% and IL-4; 0.6 ± 0.3%). Significant populations of CD20 positive B-cells were also identified. CONCLUSION: The lymphocytic infiltrate in NSIP is characterized by an elevated CD4/CD8 T-cell ratio, and is predominantly of Th1 type, with additional populations rich in B-cells. Such features are consistent with the favorable clinical course observed in patients with NSIP compared to UIP

Electronic Structure Calculation by First Principles for Strongly Correlated Electron Systems

Recent trends of ab initio studies and progress in methodologies for electronic structure calculations of strongly correlated electron systems are discussed. The interest for developing efficient methods is motivated by recent discoveries and characterizations of strongly correlated electron materials and by requirements for understanding mechanisms of intriguing phenomena beyond a single-particle picture. A three-stage scheme is developed as renormalized multi-scale solvers (RMS) utilizing the hierarchical electronic structure in the energy space. It provides us with an ab initio downfolding of the global band structure into low-energy effective models followed by low-energy solvers for the models. The RMS method is illustrated with examples of several materials. In particular, we overview cases such as dynamics of semiconductors, transition metals and its compounds including iron-based superconductors and perovskite oxides, as well as organic conductors of kappa-ET type.Comment: 44 pages including 38 figures, to appear in J. Phys. Soc. Jpn. as an invited review pape

Ceramic interface and multilayer technology for micro fuel cells

Planar fuel cells typically consist of several functional layers stacked on top of each other. We have extended the concepts of multilayer ceramics and thick film technology to provide novel approaches for the design of extremely compact and cost efficient micro fuel cells, either for the high temperature operation (SOFC) or for near ambient operation (PEMFC). Solid oxide fuel cells (SOFCs) operate at temperatures as high as 850°C. Several ceramic technologies were developed to facilitate mechanical integrity and good electrical contact to the cell at these high operating temperatures and upon rapid thermal cycling. Ceramic interconnector plates can be manufactured by adapting the multilayer / thick film / via approach known from LTCC to HTCC multilayers such as zirconia. The result is a 3D shaped SOFC interconnector plate with an unparalleled thermomechanical stability and rigidity for special applications like military. Extending that HTCC functionalisation approach further led us to the manufacturing of other multilayer ceramic based micro-reactors, namely micro-reformers for hydrogen production on a pocket size scale. We have combined several high throughput 3D shaping technologies with novel catalyst coating approaches to yield micro-reactors that are cost efficient to manufacture and that expose a high inner catalytically active surface at a low pressure drop. We have also applied thick film technologies to incorporate additional functions such as sensors or heaters right into the multilayer. The contribution is concluded with a summary of the crucial shaping and coating technologies and an outlook on how these can be applied to future compact SOFC and PEMFC fuel cells

Changes in circulating miR-375-3p and improvements in visceral and hepatic fat contents in response to lifestyle interventions: The CENTRAL trial.

OBJECTIVE: To investigate whether changes in circulating levels of pancreatic islet-related miRNA-375 (miR-375) are related to improved visceral and intrahepatic fat accumulation. RESEARCH DESIGN AND METHODS: This study included adults with abdominal obesity from an 18-month weight loss lifestyle intervention trial. Circulating miR-375-3p was measured at baseline and 18 months. MRI was performed (n = 139) to assess 18-month changes in abdominal and intrahepatic fat depots. RESULTS: Circulating miR-375-3p was related to fasting insulin and insulin resistance in participants with prediabetes. After the interventions, there was a significant increase of miR-375-3p (P < 0.001). Greater increase in miR-375-3p was associated with greater reductions of visceral (P = 0.024) and deep subcutaneous (P < 0.001) adipose tissues and intrahepatic fat content (P = 0.012). CONCLUSIONS: Increases in circulating miR-375-3p were associated with visceral and intrahepatic fat reduction. Changes in circulating pancreatic islet-related miR-375-3p may be linked to improved diabetogenic fat depots during weight loss lifestyle interventions

Changes in circulating MicroRNAs-99/100 and reductions of visceral and ectopic fat depots in response to lifestyle interventions: The CENTRAL trial.

BACKGROUND: MicroRNAs (miRNAs) are short non-coding RNAs and important post-transcriptional regulators of gene expression. Adipose tissue is a major source of circulating miRNAs; adipose-related circulating miRNAs may regulate body fat distribution and glucose metabolism. OBJECTIVES: We investigated how changes in adipose-related circulating microRNAs-99/100 (miR-99/100) in response to lifestyle interventions were associated with improved body fat distribution and reductions of diabetogenic ectopic fat depots among adults with abdominal obesity. DESIGN: This study included adults with abdominal obesity from an 18-month diet and physical activity intervention trial. Circulating levels of miR-99a-5p, miR-99b-5p, and miR-100-5p were measured at baseline and 18 months; changes in these miRNAs in response to the interventions were evaluated. The primary outcomes were changes in abdominal (visceral [VAT], deep subcutaneous [DSAT], superficial subcutaneous [SSAT]) adipose tissue (cm2) (n = 144). The secondary outcomes were changes in ectopic fat accumulation in the liver (n = 141) and pancreas (n = 143). RESULTS: Greater decreases in miR-100-5p were associated with more reductions of VAT (β per 1 SD decrease: -9.63 [SE 3.13]; P = 0.0025], DSAT (β -5.48 [2.36]; P = 0.0218), SSAT (β -4.64 [1.68]; P = 0.0067), and intrahepatic fat percentage (β -1.54 [0.49]; P = 0.0023) after the interventions. Similarly, participants with greater decrease in miR-99a-5p had larger 18-month reductions of VAT (β -10.12 [3.31] per 1 SD decrease; P = 0.0027) and intrahepatic fat percentage (β -1.28 [0.52]; P = 0.015). Further, decreases in circulating miR-99b-5p (β per 1 SD decrease: -0.44 [0.21]; P = 0.038) and miR-100-5p (β -0.50 [0.23]; P = 0.033) were associated with a decrease in pancreatic fat percentage, as well as improved glucose metabolism and insulin secretion at 18 months. CONCLUSIONS: Decreases in circulating miR-99-5p/100-5p levels induced by lifestyle interventions were related to improved body fat distribution and ectopic fat accumulation. Our study suggests that changes in circulating adipose-related miR-99-5p/100-5p may be linked to reducing diabetogenic fat depots in patients with abdominal obesity