Electron-spin-resonance And Lattice-parameter Study Of Cerium Cubic Laves-phase Compounds: Evidence For Intermediate-valence State

A lattice-constant study of the cubic C 15 Ce(IrxOs1-x)2 and Ce(PtxIr1-x)2 mixtures at room temperature reveals anomalous lattice constant versus x behavior. Also the electron-spin-resonance thermal broadening and g shift of Nd3+ in these compounds are anomalous but could be correlated with the lattice parameters. This is taken as evidence for intermediate-valence state in some of the mixtures. © 1980 The American Physical Society.45241966197

Central domain deletions affect the SAXS solution structure and function of Yeast Hsp40 proteins Sis1 and Ydj1

Background: Ydj1 and Sis1 are structurally and functionally distinct Hsp40 proteins of the yeast cytosol. Sis1 is an essential gene whereas the ydj1 gene is essential for growth at elevated temperatures and cannot complement sis1 gene deletion. Truncated polypeptides capable of complementing the sis1 gene deletion comprise the J-domain of either Sis1 or Ydj1 connected to the G/F region of Sis1 (but not Ydj1). Sis1 mutants in which the G/F was deleted but G/M maintained were capable of complementing the sis1 gene deletion. Results: To investigate the relevance of central domains on the structure and function of Ydj1 and Sis1 we prepared Sis1 constructs deleting specific domains. The mutants had decreased affinity for heated luciferase but were equally capable of stimulating ATPase activity of Hsp70. Detailed low resolution structures were obtained and the overall flexibility of Hsp40 and its mutants were assessed using SAXS methods. Deletion of either the G/M or the G/M plus CTDI domains had little impact on the quaternary structure of Sis1 analyzed by the SAXS technique. However, deletion of the ZFLR-CTDI changed the relative position of the J-domains in Ydj1 in such a way that they ended up resembling that of Sis1. The results revealed that the G/F and G/M regions are not the only flexible domains. All model structures exhibit a common clamp-like conformation. Conclusions: Our results suggest that the central domains, previously appointed as important features for substrate binding, are also relevant keeping the J-domains in their specific relative positions. The clamp-like architecture observed seems also to be favorable to the interactions of Hsp40 with Hsp70

Low-resolution structural studies of human Stanniocalcin-1

Background: Stanniocalcins (STCs) represent small glycoprotein hormones, found in all vertebrates, which have been functionally implicated in Calcium homeostasis. However, recent data from mammalian systems indicated that they may be also involved in embryogenesis, tumorigenesis and in the context of the latter especially in angiogenesis. Human STCI is a 247 amino acids protein with a predicted molecular mass of 27 kDa, but preliminary data suggested its di- or multimerization. The latter in conjunction with alternative splicing and/or post-translational modification gives rise to forms described as STC(50) and "big STC", which molecular weights range from 56 to 135 kDa. Results: In this study we performed a biochemical and structural analysis of STCI with the aim of obtaining low resolution structural information about the human STCI, since structural information in this protein family is scarce. We expressed STCI in both E. coli and insect cells using the baculo virus system with a C-terminal 6 x His fusion tag. From the latter we obtained reasonable amounts of soluble protein. Circular dichroism analysis showed STCI as a well structured protein with 52% of alpha-helical content. Mass spectroscopy analysis of the recombinant protein allowed to assign the five intramolecular disulfide bridges as well as the dimerization Cys202, thereby confirming the conservation of the disulfide pattern previously described for fish STCI. SAXS data also clearly demonstrated that STCI adopts a dimeric, slightly elongated structure in solution. Conclusion: Our data reveal the first low resolution, structural information for human STCI. Theoretical predictions and circular dichroism spectroscopy both suggested that STCI has a high content of alpha-helices and SAXS experiments revealed that STCI is a dimer of slightly elongated shape in solution. The dimerization was confirmed by mass spectrometry as was the highly conserved disulfide pattern, which is identical to that found in fish STCI

Mapping contacts between regulatory domains of skeletal muscle TnC and Tnl by analyses of a single-chain chimeras.

The troponin (Tn) complex is formed by TnC, TnI and TnT and is responsible for the calcium-dependent inhibition of muscle contraction. TnC and TnI interact in an antiparallel fashion in which the N domain of TnC binds in a calcium-dependent manner to the C domain of TnI, releasing the inhibitory effect of the latter on the actomyosin interaction. While the crystal structure of the core cardiac muscle troponin complex has been determined, very little high resolution information is available regarding the skeletal muscle TnITnC complex. With the aim of obtaining structural information regarding specific contacts between skeletal muscle TnC and TnI regulatory domains, we have constructed two recombinant chimeric proteins composed of the residues 191 of TnC linked to residues 98182 or 98147 of TnI. The polypeptides were capable of binding to the thin filament in a calcium-dependent manner and to regulate the ATPase reaction of actomyosin. Small angle X-ray scattering results showed that these chimeras fold into compact structures in which the inhibitory plus the C domain of TnI, with the exception of residues 148182, were in close contact with the N-terminal domain of TnC. CD and fluorescence analysis were consistent with the view that the last residues of TnI (148182) are not well folded in the complex. MS analysis of fragments produced by limited trypsinolysis showed that the whole TnC N domain was resistant to proteolysis, both in the presence and in the absence of calcium. On the other hand the TnI inhibitory and C-terminal domains were completely digested by trypsin in the absence of calcium while the addition of calcium results in the protection of only residues 114137

Role Of Oxygen Vacancies In The Magnetic And Dielectric Properties Of The High-dielectric-constant System Cacu3 Ti4 O12: An Electron-spin Resonance Study

We report experiments of electron spin resonance (ESR) of Cu2+ in polycrystalline samples of CaCu3 Ti4 O12 post-annealed in different atmospheres. After being synthesized by solid state reaction, pellets of CaCu3 Ti4 O12 were annealed for 24 h at 1000°C under air, Ar or O2. Our temperature dependent ESR data revealed for all samples nearly temperature independent g value (2.15(1)) and linewidth for T TN ≈25 K. However, the values of ESR linewidth are strongly affected by the oxygen content in the sample. For instance, argon post-annealed samples show a much larger linewidth than the O2 or air post-annealed samples. We attribute this broadening to an increase of the dipolar homogeneous broadening of the Cu2+ ESR lines due to the presence of oxygen vacancies which induce an S=1 2 spin inside the TiO6 octahedra. Correlation between a systematic dependence of the ESR linewidth on the oxygen content and the high dielectric constant of these materials is addressed. Also, ESR, magnetic susceptibility, and specific heat data for a single crystal of CaCu3 Ti4 O12 and for polycrystals of CdCu3 Ti4 O12 are reported. © 2006 The American Physical Society.7322Subramanian, M.A., Li, D., Duan, N., Reisner, B., Sleight, A.W., (2000) J. Solid State Chem., 151, p. 323. , JSSCBI 0022-4596 10.1006/jssc.2000.8703Ramirez, A.P., Subramanian, M.A., Gardel, M., Blumberg, G., Li, D., Vogt, T., Shapiro, S.M., (2000) Solid State Commun., 151, p. 217. , SSCOA4 0038-1098Homes, C.C., Vogt, T., Shapiro, S.M., Wakimoto, S., Ramirez, A.P., (2001) Science, 293, p. 673. , SCIEAS 0036-8075 10.1126/science.292.5517.673Lunkenheimer, P., Bobnar, V., Pronin, A.V., Ritus, A.I., Volkov, A.A., Loidl, A., (2002) Phys. Rev. B, 66, p. 052105. , PRBMDO 0163-1829 10.1103/PhysRevB.66.052105Homes, C.C., Vogt, T., Shapiro, S.M., Wakimoto, S., Subramanian, M.A., Ramirez, A.P., (2003) Phys. Rev. B, 67, p. 092106. , PRBMDO 0163-1829 10.1103/PhysRevB.67.092106Sinclair, D.C., Admas, T.B., Morrison, F.D., West, A.R., (2002) Appl. Phys. Lett., 80, p. 2153. , APPLAB 0003-6951 10.1063/1.1463211Giulloto, E., Mozzati, M.C., Azzoni, C.B., Massarotti, V., Bini, M., (2004) Ferroelectrics, 298, p. 61. , FEROA8 0015-0193Mozzati, M.C., Azzoni, C.B., Capsoni, D., Bini, M., Massarotti, V., (2003) J. Phys.: Condens. Matter, 15, p. 7365. , JCOMEL 0953-8984 10.1088/0953-8984/15/43/018Subramanian, M.A., Sleight, A.W., (2002) Solid State Sci., 4, p. 347. , SSSCFJ 1293-2558 10.1016/S1293-2558(01)01262-6Fang, L., Shen, M., Cao, W., (2004) J. Appl. Phys., 95, p. 6483. , JAPIAU 0021-8979 10.1063/1.1728308Koitzsch, A., Blumberg, G., Gozar, A., Dennis, B., Ramirez, A.P., Trebst, S., Wakimoto, S., (2002) Phys. Rev. B, 65, p. 052406. , PRBMDO 0163-1829 10.1103/PhysRevB.65.052406Bosman, A.J., Van Daal, H.J., (1970) Adv. Phys., 19, p. 1. , ADPHAH 0001-8732 10.1080/00018737000101071Lenjer, S., Schirmer, O.F., Hesse, H., Kool, T.W., (2002) Phys. Rev. B, 66, p. 165106. , PRBMDO 0163-1829 10.1103/PhysRevB.66.165106Bednorz, J.G., Mller, K.A., (1988) Rev. Mod. Phys., 60, p. 585. , RMPHAT 0034-6861 10.1103/RevModPhys.60.585Salamon, M.B., Jaime, M., (2001) Rev. Mod. Phys., 73, p. 583. , RMPHAT 0034-6861 10.1103/RevModPhys.73.583Scharfschwerdt, R., Mazur, A., Schirmer, O.F., Hesse, H., Mendricks, S., (1996) Phys. Rev. B, 54, p. 15284. , PRBMDO 0163-1829 10.1103/PhysRevB.54.15284Laguta, V.V., Slipenyuk, A.M., Bykov, I.P., Glinchuck, M.D., Maglione, M., Michau, D., Rosa, J., Jastrabik, L., (2005) Appl. Phys. Lett., 87, p. 022903. , APPLAB 0003-6951 10.1063/1.1954900Cohn, J.L., Peterca, M., Neumeier, J.J., (2005) J. Appl. Phys., 97, p. 034102. , JAPIAU 0021-8979 10.1063/1.1834976Abragam, A., Bleaney, B., (1670) Electron Paramagnetic Resonance of Transition Ions, , Clarendon, OxfordPoole, C.P., Farach, H.A., (1971) Relaxation in Magnetic Resonance, , Academic, New YorkVan Vleck, J.H., (1948) Phys. Rev., 74, p. 1168. , PHRVAO 0031-899X 10.1103/PhysRev.74.1168Anderson, P.W., Weiss, P.R., (1953) Rev. Mod. Phys., 25, p. 269. , RMPHAT 0034-6861 10.1103/RevModPhys.25.269Wu, L., Zhu, Y., Park, S., Shapiro, S., Shirane, G., Tafto, J., (1953) Rev. Mod. Phys., 25, p. 269. , RMPHAT 0034-6861 10.1103/RevModPhys.25.26

Effects of phase separation on the magnetization, x-ray diffraction, and Raman scattering of (La1-yNdy)(1-x)CaxMnO3 (y=0,0.5,1.0; x=1/3)

Dc-magnetization, x-ray diffraction, and Raman-scattering studies in polycrystalline (La1-yNdy)(t-x)CaxMnO3 (y = 0.0,0.5,1.0, and x = 1/3) samples are presented. The samples with y = 0.5 and 1.0 show complex magnetic states at low temperatures, with a ferromagnetic coupling strength that weal;ens with increasing y. X-ray measurements show a single crystallographic phase at all temperatures for y = 0.5, with lattice parameter anomalies at temperatures related to electronic and magnetic transitions. The presence of high-frequency vibrational modes in Raman-scattering measurements indicates the existence of charge- and orbital-ordered domains for y=0.5 and 1.0, which are closely related to the antiferromagnetic component identified by the magnetization experiments. The close relationship between results obtained by magnetic, structural, and optical probes is discussed.63

Effects Of Phase Separation On The Magnetization, X-ray Diffraction, And Raman Scattering Of (la1-yndy) 1-xcaxmno3 (y = 0,0.5,1.0;x = 1/3)

Dc-magnetization, x-ray diffraction, and Raman-scattering studies in polycrystalline (La1-yNdy)1-xCaxMnO3 (y = 0.0,0.5,1.0, and x = 1/3) samples are presented. The samples with y = 0.5 and 1.0 show complex magnetic states at low temperatures, with a ferromagnetic coupling strength that weakens with increasing y. X-ray measurements show a single crystallographic phase at all temperatures for y=0.5, with lattice parameter anomalies at temperatures related to electronic and magnetic transitions. The presence of high-frequency vibrational modes in Raman-scattering measurements indicates the existence of charge- and orbital-ordered domains for y = 0.5 and 1.0, which are closely related to the antiferromagnetic component identified by the magnetization experiments. The close relationship between results obtained by magnetic, structural, and optical probes is discussed.636644041644046Wollan, E.O., Koehler, W.C., (1955) Phys. Rev., 100, p. 545Goodenough, J.B., (1955) Phys. Rev., 100, p. 564Chen, C.H., Cheong, S.-W., (1996) Phys. Rev. Lett., 76, p. 4042Radaelli, P.G., Cox, D.E., Marezio, M., Cheong, S.-W., Schiffer, P.E., Ramirez, A.P., (1995) Phys. Rev. Lett., 75, p. 4488Hwang, H.Y., Cheong, S.-W., Radaelli, P.G., Marezio, M., Batlogg, B., (1995) Phys. Rev. Lett., 75, p. 914Coey, J.M.D., Viret, M., Ranno, L., Ounadjela, K., (1995) Phys. Rev. Lett., 75, p. 3910Uehara, M., Mori, S., Chen, C.H., Cheong, S.-W., (1999) Nature (London), 399, p. 560Moreo, A., Yunoke, S., Dagotto, E., (1999) Science, 283, p. 2034. , and references thereinArchibald, W., Zhou, J.-S., Goodenough, J.B., (1996) Phys. Rev. B, 53, p. 14445Zhou, J.-S., Archibald, W., Goodenough, J.B., (1996) Nature (London), 381, p. 770Rao, G.H., Sun, J.R., Liang, J.K., Zhou, W.Y., Cheng, X.R., (1996) Appl. Phys. Lett., 69, p. 424Rao, G.H., Sun, J.R., Liang, J.K., Zhou, W.Y., (1997) Phys. Rev. B, 55, p. 3742Zhou, J.-S., Goodenough, J.B., (1998) Phys. Rev. Lett., 80, p. 2665Ibarra, M.R., Zhao, G.-M., De Teresa, J.M., García-Landa, B., Arnold, Z., Marquina, C., Algarabel, P.A., Ritter, C., (1998) Phys. Rev. B, 57, p. 7446Baszynski, J., Kovac, J., Kowalczyk, A., (1999) J. Magn. Magn. Mater., 195, p. 93Moritomo, Y., (1999) Phys. Rev. B, 60, p. 10374Young, R.A., Sakthivel, A., Moss, T.S., Paiva-Santos, C.O., (1995) J. Appl. Crystallogr., 28, p. 366Radaelli, P.G., Cox, D.E., Marezio, M., Cheong, S.-W., (1997) Phys. Rev. B, 55, p. 3015Huang, Q., Santoro, A., Lynn, J.W., Erwin, R.W., Borches, J.A., Peng, J.L., Ghosh, K., Greene, R.L., (1998) Phys. Rev. B, 58, p. 2684Irwin, J.C., Chrzanowski, J., Franck, J.P., (1999) Phys. Rev. B, 59, p. 9362Abrashev, M.V., Ivanov, V.G., Iliev, M.N., Chakalov, R.A., Chakalova, R.I., Thomsen, C., (1999) Phys. Status Solidi B, 215, p. 631Liarokapis, E., Leventouri, Th., Lampakis, D., Palles, D., Neumeier, J.J., Goodwin, D.H., (1999) Phys. Rev. B, 60, p. 12758Granado, E., Moreno, N.O., García, A., Sanjurjo, J.A., Rettori, C., Torriani, I., Oseroff, S.B., Tokura, Y., (1998) Phys. Rev. B, 58, p. 11435Yoon, S., Liu, H.L., Schollerer, G., Cooper, S.L., Han, P.D., Payne, D.A., Cheong, S.-W., Fisk, Z., (1998) Phys. Rev. B, 58, p. 2795Liu, H.L., Yoon, S., Cooper, S.L., Cheong, S.-W., Han, P.D., Payne, D.A., (1998) Phys. Rev. B, 58, pp. R10115Liu, K., Wu, X.W., Ahn, K.H., Sulchek, T., Chien, C.L., Xiao, J.Q., (1996) Phys. Rev. B, 54, p. 3007Granado, E., Pagliuso, P.G., Sanjurjo, J.A., Rettori, C., Oseroff, S.B., Causa, M.T., Butera, A., Schultz, S., (1998) Non-Crystalline and Nanoscale Materials, pp. 105-115. , edited by J. Rivas and M.A. López-Quintela (World Scientific, Singapore)Granado, E., Sanjurjo, J.A., Rettori, C., Prado, F., Sánchez, R.D., Caneiro, A., Oseroff, S.B., (2000) Phys. Status Solidi B, 220, p. 609Dediu, V., Ferdeghini, C., Matacotta, F.C., Nozar, P., Ruani, G., (2000) Phys. Rev. Lett., 84, p. 4489Adams, C.P., Lynn, J.W., Mukovskii, Y.M., Arsenov, A.A., Shulyatev, D.A., (2000) Phys. Rev. Lett., 85, p. 3954Dai, P., Fernandez-Baca, J.A., Wakabayashi, N., Plummer, E.W., Tomioka, Y., Tokura, Y., (2000) Phys. Rev. Lett., 85, p. 255

Reliability and predictive validity of a hepatitis-related symptom inventory in HIV-infected individuals referred for Hepatitis C treatment

<p>Abstract</p> <p>Background</p> <p>We aimed to determine the reliability and validity of a hepatitis symptom inventory and to identify predictors of hepatitis C (HCV) treatment initiation in a cohort of HIV-infected patients.</p> <p>Methods</p> <p>Prospective clinic based study that enrolled patients referred for HCV therapy consideration. A hepatitis symptom inventory and the Center for Epidemiologic Studies Depression Scale (CES-D) were administered to HIV/HCV individuals. The symptom inventory was factor analyzed and subscale reliability estimated with Cronbach's alpha. Predictive validity was evaluated using generalized estimating equations (GEE). Predictors of HCV treatment were identified using logistic regression.</p> <p>Results</p> <p>Between April 2008 to July 2010, 126 HIV/HCV co-infected patients were enrolled in the study. Factor analysis using data from 126 patients yielded a three-factor structure explaining 60% of the variance for the inventory. Factor 1 (neuropsychiatric symptoms) had 14 items, factor 2 (somatic symptoms) had eleven items, and factor 3 (sleep symptoms) had two items, explaining 28%, 22% and 11% of the variance, respectively. The three factor subscales demonstrated high intrinsic consistency reliability. GEE modeling of the 32 patients who initiated HCV therapy showed that patients developed worsening neuropsychiatric and somatic symptoms following HCV therapy with stable sleep symptoms. Bivariate analyses identified the following as predictors of HCV therapy initiation: lower HIV log₁₀RNA, lower scores for neuropsychiatric, somatic and sleep symptoms, lower CES-D scores and white ethnicity. In stepwise multiple logistic regression analysis, low neuropsychiatric symptom score was the strongest independent predictor of HCV therapy initiation and HIV log₁₀RNA was inversely associated with a decision to initiate HCV treatment.</p> <p>Conclusions</p> <p>A 41-item hepatitis-related symptom inventory was found to have a clinically meaningful 3-factor structure with excellent internal consistency reliability and predictive validity. In adjusted analysis, low neuropsychiatric symptom scores and controlled HIV infection were independent predictors of HCV treatment initiation. The usefulness of the HCV symptom inventory in monitoring HCV treatment should be evaluated prospectively.</p

Combined pangenomics and transcriptomics reveals core and redundant virulence processes in a rapidly evolving fungal plant pathogen

Background Studying genomic variation in rapidly evolving pathogens potentially enables identification of genes supporting their “core biology”, being present, functional and expressed by all strains or “flexible biology”, varying between strains. Genes supporting flexible biology may be considered to be “accessory”, whilst the “core” gene set is likely to be important for common features of a pathogen species biology, including virulence on all host genotypes. The wheat-pathogenic fungus Zymoseptoria tritici represents one of the most rapidly evolving threats to global food security and was the focus of this study. Results We constructed a pangenome of 18 European field isolates, with 12 also subjected to RNAseq transcription profiling during infection. Combining this data, we predicted a “core” gene set comprising 9807 sequences which were; (1) present in all isolates; (2) lacking inactivating polymorphisms; and (3) expressed by all isolates. A large accessory genome, consisting of 45% of the total genes was also defined. We classified genetic and genomic polymorphism at both chromosomal and individual gene scales. Proteins required for essential functions including virulence, had lower-than average sequence variability amongst core genes. Both core and accessory genomes encoded many small, secreted candidate effector proteins that likely interact with plant immunity. Viral vector-mediated transient in planta overexpression of 88 candidates failed to identify any which induced leaf necrosis characteristic of disease. However, functional complementation of a non-pathogenic deletion mutant lacking five core genes, demonstrated that full virulence was restored by re-introduction of the single gene exhibiting least sequence polymorphism and highest expression. Conclusions These data support the combined use of pangenomics and transcriptomics for defining genes which represent core, and potentially exploitable, weaknesses in rapidly evolving pathogens

Altered miRNA processing disrupts brown/white adipocyte determination and associates with lipodystrophy

miRNAs are important regulators of biological processes in many tissues, including the differentiation and function of brown and white adipocytes. the endoribonuclease dicer is a major component of the miRNA-processing pathway, and in adipose tissue, levels of dicer have been shown to decrease with age, increase with caloric restriction, and influence stress resistance. Here, we demonstrated that mice with a fat-specific KO of dicer develop a form of lipodystrophy that is characterized by loss of intra-abdominal and subcutaneous white fat, severe insulin resistance, and enlargement and whitening of interscapular brown fat. Additionally, KO of dicer in cultured brown preadipocytes promoted a white adipocyte-like phenotype and reduced expression of several miRNAs. Brown preadipocyte whitening was partially reversed by expression of miR-365, a miRNA known to promote brown fat differentiation; however, introduction of other miRNAs, including miR-346 and miR-362, also contributed to reversal of the loss of the dicer phenotype. Interestingly, fat samples from patients with HIV-related lipodystrophy exhibited a substantial downregulation of dicer mRNA expression. Together, these findings indicate the importance of miRNA processing in white and brown adipose tissue determination and provide a potential link between this process and HIV-related lipodystrophy.NIHEllison FoundationJoslin Diabetes and Endocrinology Research Center coresMary K. Iacocca ProfessorshipAcademy of FinlandSigrid Juselius FoundationFundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Harvard Univ, Sch Med, Joslin Diabet Ctr, Sect Integrat Physiol & Metab, Boston, MA 02115 USAUniversidade Federal de São Paulo, Dept Biophys, São Paulo, BrazilUniversidade Federal de São Paulo, Program Mol Biol, São Paulo, BrazilAstraZeneca R&D, Cardiovasc & Metab Dis iMed, Molndal, SwedenUniv Helsinki, Dept Med, Helsinki, FinlandMinerva Fdn, Inst Med Res, Helsinki, FinlandUniv Massachusetts, Sch Med, Program Mol Med, Worcester, MA USAMassachusetts Gen Hosp, Program Nutr Metab, Boston, MA 02114 USAHarvard Univ, Sch Med, Boston, MA USAUniversidade Federal de São Paulo, Dept Biophys, São Paulo, BrazilUniversidade Federal de São Paulo, Program Mol Biol, São Paulo, BrazilNIH: DK082659NIH: DK033201NIH: AI060354NIH: DK040561NIH: U24-DK093000Joslin Diabetes and Endocrinology Research Center cores: DK036836FAPESP: 2010/52557-0Web of Scienc