303 research outputs found

    Structural Features of Layered Iron Pnictide Oxides (Fe2As2)(Sr4M2O6)

    Full text link
    Structural features of newly found perovskite-based iron pnictide oxide system have been systematically studied. Compared to REFePnO system, perovskite-based system tend to have lower Pn-Fe-Pn angle and higher pnictogen height owing to low electronegativity of alkaline earth metal and small repulsive force between pnictogen and oxygen atoms. As-Fe-As angles of (Fe2As2)(Sr4Cr2O6), (Fe2As2)(Sr4V2O6) and (Fe2Pn2)(Sr4MgTiO6) are close to ideal tetrahedron and those pnictogen heights of about 1.40 A are close to NdFeAsO with optimized carrier concentration. These structural features of this system may leads to realization of high Tc superconductivity.Comment: 3pages, 2figures, 1table, proceedings of M2S 200

    Time-resolved photoelectron spectroscopy of proton transfer in the ground state of chloromalonaldehyde: Wave-packet dynamics on effective potential surfaces of reduced dimensionality

    Get PDF
    We report on a simple but widely useful method for obtaining time-independent potential surfaces of reduced dimensionality wherein the coupling between reaction and substrate modes is embedded by averaging over an ensemble of classical trajectories. While these classically averaged potentials with their reduced dimensionality should be useful whenever a separation between reaction and substrate modes is meaningful, their use brings about significant simplification in studies of time-resolved photoelectron spectra in polyatomic systems where full-dimensional studies of skeletal and photoelectron dynamics can be prohibitive. Here we report on the use of these effective potentials in the studies of dump-probe photoelectron spectra of intramolecular proton transfer in chloromalonaldehyde. In these applications the effective potentials should provide a more realistic description of proton-substrate couplings than the sudden or adiabatic approximations commonly employed in studies of proton transfer. The resulting time-dependent photoelectron signals, obtained here assuming a constant value of the photoelectron matrix element for ionization of the wave packet, are seen to track the proton transfer. (c) 2006 American Institute of Physics.1241

    MITSuME--Multicolor Imaging Telescopes for Survey and Monstrous Explosions

    Get PDF
    Development of MITSuME is reported. Two 50-cm optical telescopes have been built at Akeno in Yamanashi prefecture and at Okayama Astrophysical Observatory (OAO) in Okayama prefecture. Three CCD cameras for simultaneous g'RcIc photometry are to be mounted on each focal plane, covering a wide FOV of about 30" x 30". The limiting magnitude at V is fainter than 18. In addition to these two optical telescopes, a 91-cm IR telescope with a 1 deg x 1 deg field of view is being built at OAO, which performs photometry in YJHK bands. These robotic telescopes can start the observation of counterparts of a GRB within a minute from an alert. We aim to obtain photometric redshifts exceeding 10 with these telescopes. The performance and the current construction status of the telescopes are presented.Comment: 4 pages, 3 figures, 4th Workshop on Gamma-Ray Burst in the Afterglow Era, Roma, October 18-22, 200

    Lack of association between estrogen receptor β dinucleotide repeat polymorphism and autoimmune thyroid diseases in Japanese patients

    Get PDF
    BACKGROUND: The autoimmune thyroid diseases (AITDs), such as Graves' disease (GD) and Hashimoto's thyroiditis (HT), appear to develop as a result of complex interactions between predisposing genes and environmental triggers. Susceptibility to AITDs is conferred by genes in the human leukocyte antigen (HLA) and genes unlinked to HLA, including the CTLA-4 gene. Recently, estrogen receptor (ER) β, located at human chromosome 14q23-24.1, was identifed. We analyzed a dinucleotide (CA)n repeat polymorphism located in the flanking region of ERβ gene in patients with AITDs and in normal subjects. High heterozygosity makes this polymorphism a useful marker in the genetic study of disorders affecting female endocrine systems. We also correlated a ERβ gene microsatellite polymorphism with bone mineral density (BMD) in the distal radius and biochemical markers of bone turnover in patients with GD in remission. RESULTS: Fourteen different alleles were found in 133 patients with GD, 114 patients with HT, and 179 controls subjects. The various alleles were designated as allele(*)1 through allele(*)14 according to the number of the repeats, from 18 to 30. There was no significant difference in the distributions of ERβ alleles between patient groups and controls. Although recent study demonstrated a significant relation between a allele(*)9 in the ERβ gene and BMD in postmenopausal Japanese women, there were no statistically significant interaction between this allele and BMD in the distal radius, nor biochemical markers in patients with GD in remission. CONCLUSIONS: The present results do not support an association between the ERβ microsatellite marker and AITD in the Japanese population. We also suggest that the ERβ microsatellite polymorphism has at most a minor pathogenic importance in predicting the risk of osteoporosis as a complication of GD

    Expression of genes for estrogen receptors α and β in human articular chondrocytes

    Get PDF
    AbstractObjective To investigate the gene expression of estrogen receptor (ER) α and ERβ in human articular chondrocytes.Methods 16 articular cartilage specimens were obtained from 15 patients during surgery. Three of the specimens were from men and 13 from women; three from hip joints and 13 from knee joints; four were normal and 12 showed osteoarthritic cartilage. Total RNA was extracted from the articular chondrocytes and the expression of both ERα and ERβ genes was investigated by the reverse transcription-polymerase chain reaction (RT-PCR) method.Results Gene expressions of ERα were detected in all specimens and those of ERβ were found in 15 specimens by the RT-PCR method. There was a significant correlation between the amounts of ERα and ERβ. Expression levels of both genes were significantly higher in men than in women. There were no significant differences in the expression levels of both ER genes between the hip and knee joint sites, nor between normal and osteoarthritic tissues.Conclusion This study is to our knowledge the first to demonstrate the gene expression of both ERα and ERβ in human articular chondrocytes. Since there are some functional differences between the two receptors, the effects of estrogen on cartilage metabolism should be elucidated by two different receptor mechanisms.{copy

    The utility of pathway selective estrogen receptor ligands that inhibit nuclear factor-κB transcriptional activity in models of rheumatoid arthritis

    Get PDF
    Rheumatoid arthritis (RA) is a chronic inflammatory disease that produces synovial proliferation and joint erosions. The pathologic lesions of RA are driven through the production of inflammatory mediators in the synovium mediated, in part, by the transcription factor NF-κB. We have identified a non-steroidal estrogen receptor ligand, WAY-169916, that selectively inhibits NF-κB transcriptional activity but is devoid of conventional estrogenic activity. The activity of WAY-169916 was monitored in two models of arthritis, the HLA-B27 transgenic rat and the Lewis rat adjuvant-induced model, after daily oral administration. In both models, a near complete reversal in hindpaw scores was observed as well as marked improvements in the histological scores. In the Lewis rat adjuvant model, WAY-169916 markedly suppresses the adjuvant induction of three serum acute phase proteins: haptoglobin, α1-acid glycoprotein (α1-AGP), and C-reactive protein (CRP). Gene expression experiments also demonstrate a global suppression of adjuvant-induced gene expression in the spleen, liver, and popliteal lymph nodes. Finally, WAY-169916 was effective in suppressing tumor necrosis factor-α-mediated inflammatory gene expression in fibroblast-like synoviocytes isolated from patients with RA. Together, these data suggest the utility of WAY-169916, and other compounds in its class, in treating RA through global suppression of inflammation via selective blockade of NF-κB transcriptional activity

    Common genetic variation in the Estrogen Receptor Beta (ESR2) gene and osteoarthritis: results of a meta-analysis

    Get PDF
    Background: The objective of this study was to examine the relationship between common genetic variation of the ESR2 gene and osteoarthritis.Methods: In the discovery study, the Rotterdam Study-I, 7 single nucleotide polymorphisms (SNPs) were genotyped and tested for association with hip (284 cases, 2772 controls), knee (665 cases, 2075 controls), and hand OA (874 cases, 2184 controls) using an additive model. In the replication stage one SNP (rs1256031) was tested in an additional 2080 hip, 1318 knee and 557 hand OA cases and 4001, 2631 and 1699 controls respectively. Fixed- and random-effects meta-analyses were performed over the complete dataset including 2364 hip, 1983 knee and 1431 hand OA cases and approximately 6000 controls.Results: The C allele of rs1256031 was associated with a 36% increased odds of hip OA in women of the Rotterdam Study-I (OR 1.36, 95% CI 1.08-1.70, p = 0.009). Haplotype analysis and analysis of knee- and hand OA did not give additional information. With the replication studies, the meta-analysis did not show a significant effect of this SNP on hip OA in the total population (OR 1.06, 95% CI 0.99-1.15, p = 0.10). Stratification according to gender did not change the results. In this study, we had 80% power to detect an odds ratio of at least 1.14 for hip OA (α = 0.05).Conclusion: This study showed that common genetic variation in the ESR2 gene is not likely to influence the risk of osteoarthritis with effects smaller than a 13% increase

    Vitamin D and oestrogen receptor polymorphisms in developmental dysplasia of the hip and primary protrusio acetabuli – A preliminary study

    Get PDF
    We investigated the association of developmental dysplasia of the hip (DDH) and primary protrusion acetabuli (PPA) with Vitamin D receptor polymorphisms Taq I and Fok I and oestrogen receptor polymorphisms Pvu II and Xba I. 45 patients with DDH and 20 patients with PPA were included in the study. Healthy controls (n = 101) aged 18–60 years were recruited from the same geographical area. The control subjects had a normal acetabular morphology based on a recent pelvic radiograph performed for an unrelated cause. DNA was obtained from all the subjects from peripheral blood. Genotype frequencies were compared in the three groups. The relationship between the genotype and morphology of the hip joint, severity of the disease, age at onset of disease and gender were examined. The oestrogen receptor Xba I wild-type genotype (XX, compared with Xx and xx combined) was more common in the DDH group (55.8%) than controls (37.9%), though this just failed to achieve statistical significance (p = 0.053, odds ratio = 2.1, 95% CI = 0.9–4.6). In the DDH group, homozygosity for the mutant Taq I Vitamin D receptor t allele was associated with higher acetabular index (Mann-Whitney U-test, p = 0.03). Pvu II pp oestrogen receptor genotype was associated with low centre edge angle (p = 0.07). This study suggests a possible correlation between gene polymorphism in the oestrogen and vitamin D receptors and susceptibility to, and severity of DDH. The Taq I vitamin D receptor polymorphisms may be associated with abnormal acetabular morphology leading to DDH while the Xba I oestrogen receptor XX genotype may be associated with increased risk of developing DDH. No such correlations were found in the group with PPA
    corecore