Engineering Transport Properties in Interconnected Enargite-Stannite Type Cu2+x Mn1-x GeS4 Nanocomposites.

Understanding the mechanisms that connect heat and electron transport with crystal structures and defect chemistry is fundamental to develop materials with thermoelectric properties. In this work, we synthesized a series of self-doped compounds Cu2+x Mn1-x GeS4 through Cu for Mn substitution. Using a combination of powder X-ray diffraction, high resolution transmission electron microscopy and precession-assisted electron diffraction tomography, we evidence that the materials are composed of interconnected enargite- and stannite-type structures, via the formation of nanodomains with a high density of coherent interfaces. By combining experiments with ab initio electron and phonon calculations, we discuss the structure-thermoelectric properties relationships and clarify the interesting crystal chemistry in this system. We demonstrate that excess Cu+ substituted for Mn2+ dopes holes into the top of the valence band, leading to a remarkable enhancement of the power factor and figure of merit ZT.

Nonrandom point defect configurations and driving force transitions for grain boundary segregation in trivalent cation doped ZrO2.

The energetically favorable spatial configuration of M(3+) ions and oxide-ion vacancies near a symmetrical grain boundary (GB) in cubic zirconia is determined for various trivalent species M(3+) (M = Al, Sc, Y, Gd, La), and the driving force for grain boundary segregation (GBS) quantitatively examined using atomistic Monte Carlo simulations in conjunction with static lattice calculations. For a high concentration of ∼10 mol %, it is found that point defects near a GB plane preferentially occupy specific sites to minimize total lattice energy, rather than being randomly distributed. Systematic analysis shows that energetically stable configurations of segregants vary depending on their ionic radii. Analysis of the driving force for GBS as a function of dopant concentration reveals that three important factors govern GBS. First, occupation of specific sites by point defects is necessary to minimize the total lattice energy; enrichment of point defects near the GB plane with random configuration does not decrease the total lattice energy significantly because of strong Coulombic interactions. Second, the factors governing GBS change with increasing dopant concentration. At dilute concentrations, relief of bond strain is the dominant factor, while at high concentrations Coulombic interactions, which depend strongly on the specific arrangement of defects, become another dominant factor. Third, the stabilization of matrix cations, Zr(4+) ions, is the dominant factor to lower the driving force for GBS at all concentrations. In contrast, the stabilization of M(3+) ions does not necessarily contribute to GBS of point defects at high concentrations. These findings suggest practical ways to control GBS to enhance materials' properties or minimize detrimental effects.

Infection of different strains of mice with Lawsonia intracellularis derived from rabbit or porcine proliferative enteropathy.

This report describes intestinal lesions in five strains of mice infected orally with Lawsonia intracellularis-infected tissue homogenates from rabbits or pigs (RLI and PLI). BALB/cA, C3H/HeJ, C57BL/6J and ICR mice were susceptible to infection with RLI, whereas only C3H/HeJ, C57BL/6J and ICR strains were susceptible to PLI. In susceptible mice, crypt epithelial hyperplasia occurred in association with an inflammatory reaction, as in proliferative enteropathy (PE) in other species. The intestinal changes in the infected mice varied from mild to severe. Unlike rabbit or porcine PE, in which the changes are confined to the ileum, the lesions in mice were located in the caecum. Immunolabelling of L. intracellularis antigen was abundant in early infection when the epithelial hyperplasia was mild or absent. When the hyperplasia had become severe, however, immunolabelling was weak. For this reason, it is suggested that transitory infection of the epithelium induces epithelial hyperplasia. Genetic differences between mouse strains appeared to play an important role in the response to L. intracellularis infection. Moreover, the susceptibility of BALB/cA mice to RLI but not to PLI suggests that there are significant biological differences between L. intracellularis isolates from rabbit PE and porcine PE.

Role of the kidney in the plasma clearance of angiotensinogen in the rat: plasma clearance and tissue distribution of 125I-angiotensinogen.

We studied the tissue distribution and plasma clearance of angiotensinogen (AGN) in rats following an i.v. injection of 125I-labeled AGN. The plasma clearance rate of [125I]AGN fits a two-compartment model with half-lives of 10.2 +/- 1.5 min and 4.1 +/- 0.5 h in non-treated rats, and the half-life of slower phase significantly increased to 10.2 +/- 1.1 h following bilateral nephrectomy. Radioactivity was predominantly distributed in the kidneys (4.9%), and to a lesser extent in the liver (1.8%), testis (1.2%), spleen (0.61%), heart (0.35%), lung (0.18%), thymus (0.03%) and brain (0.03%). The subcellular distribution of radioactivity in the kidney was 64% in the soluble fraction and 33% in the crude mitochondrial-lysosomal fraction. Sodium dodecylsulfate-polyacrylamide gel electrophoresis revealed that the radioactivity in the soluble fraction consisted of proteins corresponding to intact [125I]AGN, whereas the mitochondrial-lysosomal fraction contained additional radioactive proteins with molecular weights between 18,000 and 29,000. When isolated kidney cells were incubated with [125I]AGN at 0 degree C, the radioactive binding was saturable and specific with a Kd value of 4.8 x 10(-11)M, whereas incubation at 37 degrees C resulted in the appearance of degraded products of [125I]AGN in the medium. These results suggested that circulating AGN is cleared mainly by the kidneys via receptor-mediated endocytosis, which may play an important role in regulating plasma level of AGN.

Electron-energy-loss near edge structures of six-fold-coordinated Zn in MgO.

Electron-energy-loss near edge structures (ELNES) at the Zn-L(2,3) edge and the O-K edge have been measured for 10 mol% ZnO-doped MgO, and were compared with spectra from reference materials. In order to interpret the spectra, first principles molecular orbital calculations were made using model clusters composed of 125 and 153 atoms. Photoabsorption cross sections (PACS) were computed at the Slater's transition state in which a half-filled core hole was included in the self-consistent calculations. The difference in the coordination numbers of Zn was found well distinguishable by the Zn-L(2,3)-edge ELNES. The experimental spectra in the first 25 eV were well reproduced by the theoretical PACS. In this energy region, the Zn-L(2,3)-edge ELNES from four-fold coordinated Zn showed four sets of peaks, whereas the six-fold coordinated Zn exhibits three sets of peaks. The origin of these peaks can be explained by the point symmetry within the first coordination unit. A small shift toward the lower energy side was observed in the O-K edge ELNES of the ZnO-doped MgO as compared with pure MgO. This can be ascribed to the lower energy of the Zn-4s orbital as compared with the Mg-3s orbital, which is the common mechanism to the difference in the band gap between MgO and ZnO.

Angiotensinogen excretion in rat urine: effects of lipopolysaccharide treatment and sodium balance.

Rat urine was found to contain a component showing cross-reactivity with antibody against rat plasma angiotensinogen. Sodium dodecyl sulfate polyacrylamide gel electrophoresis of rat urine revealed antigenic bands corresponding to the molecular weights of plasma angiotensinogen. The urinary angiotensinogen excretion in 8 rats, determined by direct radioimmunoassay, was 2.70 +/- 0.21 micrograms/day. Induction of acute inflammation in rats by injection of lipopolysaccharide caused about a 7-fold increase of urinary angiotensinogen excretion in the 24 hr after injection, with a concomitant elevation of plasma angiotensinogen. Neither sodium depletion nor loading by a low- or high-sodium diet altered the urinary excretion of angiotensinogen. These results suggest that the angiotensinogen present in rat urine is derived from that in plasma, although the level of excretion is too low to have any influence on the plasma level of angiotensinogen.

Prolonged infection of the floor of the mouth in hyperimmunoglobulinemia E (Buckley's syndrome). Report of a case.

A case of prolonged infection of the floor of the mouth with a generalized eczematous dermatitis in a 13-year-old boy is described. Immunologic examination revealed markedly elevated serum concentration of immunoglobulin E (IgE) and impaired neutrophil chemotaxis. The disorder was diagnosed as the hyperimmunoglobulinemia E (Buckley's syndrome) and was successfully treated with high doses of antibiotics and human immunoglobulin.

Clinical trial of recombinant granulocyte colony-stimulating factor for chemotherapy-induced neutropenia patients with oral cancer.

PURPOSE: This study was undertaken to evaluate the efficacy and toxicity of recombinant human granulocyte colony-stimulating factor (rhG-CSF) in reducing neutropenia in patients with oral cancer undergoing intensive chemotherapy. MATERIALS AND METHODS: Patients with chemotherapy-induced neutropenia (< 1 x 10(9)/L) were divided into two groups: control group (n = 13) and rhG-CSF administration group (n = 16). rhG-CSF was administered subcutaneously at a dose of 75 micrograms/day on consecutive days. Peripheral blood cell counts and oral complications were investigated in each group. RESULTS: The duration of neutropenia and absolute neutrophil nadir counts were significantly improved by administration of G-CSF. No consistent effect on thrombocytopenia was noted. Administration of rhG-CSF also reduced the duration and degree of oral complications associated with chemotherapy-induced neutropenia. Intolerable side effects associated with administration of rhG-CSF were not observed. CONCLUSION: It was concluded that rhG-CSF is effective in shortening the duration of neutropenia after chemotherapy at a dose of 75 micrograms/day.