98 research outputs found
Recent advances in deuterium permeation induced transmutation experiments using nano-structured Pd/CaO/Pd multilayer thin film
Permeation induced transmutation reactions, which we originally found in the nanostructured Pd multilayer film composed of Pd and CaO thin film and Pd substrate, have been observed in our laboratory and other research institutes. Recently, Toyota R&D centre reported almost complete replication experiments on the transmutation of Cs into Pr at ICCF-17. We observed transmutation reactions of Cs into Pr, Ba into Sm, W into Pt up to now. Especially, transmutation of Cs into Pr has been confirmed by "in-situ" measurements using x-ray fluorescence spectrometry (XRF) at SPring-8 in Japan. Experimental data that indicates the presence of transmutation have been accumulated and the underlying mechanism for inducing low energy transmutation reactions is gradually becoming clear, although systematic experimental study is still insufficient. The permeation induced transmutation technology would be expected as an innovative nuclear transmutation method for radioactive waste and a new energy source if we would be able to increase the amount of transmutation products. We have been trying to increase the amount of transmutation products these years for the practical application. The following factors are assumed to be important for inducing deuterium permeation transmutation. 1) Local Deuteron Density 2) Electronic Structure Based on this assumption, we applied an electrochemical method to increase the local deuteron density near the surface of the nano-structured Pd multilayer film. We also tried to increase the transmutation products by changing surface electronic state. These recent experimental methods gave us increased transmutation products, gamma-ray emissions, and new implications on Deuterium Permeation Induced Transmutation
Imperfect Information, Heterogeneous Demand Shocks, and Inflation Dynamics
Using sector-level survey data for the universe of Japanese firms, we establish the positive co-movement in the firm’s expectations about aggregate and sector-specific demand shocks. We show that a simple model with imperfect information on the current aggregate and sector-specific components of demand explains the positive co-movement of expectations in the data. The model predicts that an increase in the relative volatility of sector-specific demand shocks compared to aggregate demand shocks reduces
the sensitivity of inflation to changes in aggregate demand. We test and corroborate the theoretical prediction on Japanese data and find that the observed decrease in the relative volatility of sector-specific demand has played a significant role for the decline in the sensitivity of inflation to movements in aggregate demand from mid-1980s to mid-2000s
Identification of DBC1 as a transcriptional repressor for BRCA1
BACKGROUND: DBC1/KIAA1967 (deleted in breast cancer 1) is a putative tumour-suppressor gene cloned from a heterozygously deleted region in breast cancer specimens. Caspase-dependent processing of DBC1 promotes apoptosis, and depletion of endogenous DBC1 negatively regulates p53-dependent apoptosis through its specific inhibition of SIRT1. Hereditary breast and ovarian cancer susceptibility gene product BRCA1, by binding to the promoter region of SIRT1, is a positive regulator of SIRT1 expression. METHODS: A physical interaction between DBC1 and BRCA1 was investigated both in vivo and in vitro. To determine the pathophysiological significance of DBC1, its role as a transcriptional factor was studied. RESULTS: We found a physical interaction between the amino terminus of DBC1 and the carboxyl terminus of BRCA1, also known as the BRCT domain. Endogenous DBC1 and BRCA1 form a complex in the nucleus of intact cells, which is exported to the cytoplasm during ultraviolet-induced apoptosis. We also showed that the expression of DBC1 represses the transcriptional activation function of BRCT by a transient expression assay. The expression of DBC1 also inhibits the transactivation of the SIRT1 promoter mediated by full-length BRCA1. CONCLUSION: These results revealed that DBC1 may modulate the cellular functions of BRCA1 and have important implications in th
Protective Effects of Radon Inhalation on Carrageenan-Induced Inflammatory Paw Edema in Mice
We assessed whether radon inhalation inhibited carrageenan-induced inflammation in mice. Carrageenan (1% v/v) was injected subcutaneously into paws of mice that had or had not inhaled approximately 2,000 Bq/m3 of radon for 24 h. Radon inhalation significantly increased superoxide dismutase (SOD) and catalase activities and significantly decreased lipid peroxide levels in mouse paws, indicating that radon inhalation activates antioxidative functions. Carrageenan administration induced paw edema and significantly increased tumor necrosis factor-alpha (TNF-α) and nitric oxide in serum. However, radon inhalation significantly reduced carrageenan-induced paw edema. Serum TNF-α levels were lower in the radon-treated mice than in sham-treated mice. In addition, SOD and catalase activities in paws were significantly higher in the radon-treated mice than in the sham-treated mice. These findings indicated that radon inhalation had anti-inflammatory effects and inhibited carrageenan-induced inflammatory paw edema
The ATR-Chk1 pathway plays a role in the generation of centrosome aberrations induced by Rad51C dysfunction
Rad51C is a central component of two complexes formed by five Rad51 paralogs in vertebrates. These complexes are involved in repairing DNA double-strand breaks through homologous recombination. Despite accumulating evidence suggesting that the paralogs may prevent aneuploidy by controlling centrosome integrity, Rad51C's role in maintaining chromosome stability remains unclear. Here we demonstrate that Rad51C deficiency leads to both centrosome aberrations in an ATR-Chk1-dependent manner and increased aneuploidy in human cells. While it was reported that Rad51C deficiency did not cause centrosome aberrations in interphase in hamster cells, such aberrations were observed in interphase in HCT116 cells with Rad51C dysfunction. Caffeine treatment and down-regulation of ATR, but not that of ATM, reduced the frequency of centrosome aberrations in the mutant cells. Silencing of Rad51C by RNA interference in HT1080 cells resulted in similar aberrations. Treatment with a Chk1 inhibitor and silencing of Chk1 also reduced the frequency in HCT116 mutants. Accumulation of Chk1 at the centrosome and nuclear foci of γH2AX were increased in the mutants. Moreover, the mutant cells had a higher frequency of aneuploidy. These findings indicate that the ATR-Chk1 pathway plays a role in increased centrosome aberrations induced by Rad51C dysfunction
HmuY Haemophore and Gingipain Proteases Constitute a Unique Syntrophic System of Haem Acquisition by Porphyromonas gingivalis
Haem (iron protoporphyrin IX) is both an essential growth factor and virulence regulator for the periodontal pathogen Porphyromonas gingivalis, which acquires it mainly from haemoglobin via the sequential actions of the R- and K-specific gingipain proteases. The haem-binding lipoprotein haemophore HmuY and its cognate receptor HmuR of P. gingivalis, are responsible for capture and internalisation of haem. This study examined the role of the HmuY in acquisition of haem from haemoglobin and the cooperation between HmuY and gingipain proteases in this process. Using UV-visible spectroscopy and polyacrylamide gel electrophoresis, HmuY was demonstrated to wrest haem from immobilised methaemoglobin and deoxyhaemoglobin. Haem extraction from oxyhaemoglobin was facilitated after oxidation to methaemoglobin by pre-treatment with the P. gingivalis R-gingipain A (HRgpA). HmuY was also capable of scavenging haem from oxyhaemoglobin pre-treated with the K-gingipain (Kgp). This is the first demonstration of a haemophore working in conjunction with proteases to acquire haem from haemoglobin. In addition, HmuY was able to extract haem from methaemalbumin, and could bind haem, either free in solution or from methaemoglobin, even in the presence of serum albumin
Human Sclera Maintains Common Characteristics with Cartilage throughout Evolution
BACKGROUND: The sclera maintains and protects the eye ball, which receives visual inputs. Although the sclera does not contribute significantly to visual perception, scleral diseases such as refractory scleritis, scleral perforation and pathological myopia are considered incurable or difficult to cure. The aim of this study is to identify characteristics of the human sclera as one of the connective tissues derived from the neural crest and mesoderm. METHODOLOGY/PRINCIPAL FINDINGS: We have demonstrated microarray data of cultured human infant scleral cells. Hierarchical clustering was performed to group scleral cells and other mesenchymal cells into subcategories. Hierarchical clustering analysis showed similarity between scleral cells and auricular cartilage-derived cells. Cultured micromasses of scleral cells exposed to TGF-betas and BMP2 produced an abundant matrix. The expression of cartilage-associated genes, such as Indian hedge hog, type X collagen, and MMP13, was up-regulated within 3 weeks in vitro. These results suggest that human 'sclera'-derived cells can be considered chondrocytes when cultured ex vivo. CONCLUSIONS/SIGNIFICANCE: Our present study shows a chondrogenic potential of human sclera. Interestingly, the sclera of certain vertebrates, such as birds and fish, is composed of hyaline cartilage. Although the human sclera is not a cartilaginous tissue, the human sclera maintains chondrogenic potential throughout evolution. In addition, our findings directly explain an enigma that the sclera and the joint cartilage are common targets of inflammatory cells in rheumatic arthritis. The present global gene expression database will contribute to the clarification of the pathogenesis of developmental diseases such as high myopia
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Neurogenic foreign accent syndrome: Articulatory setting, segments and prosody in a Dutch speaker
Foreign accent syndrome (FAS) can be defined as a motor speech disorder in which patients develop a speech accent which is notably different from their premorbid habitual accent. This paper aims to provide an explicit description of the neurolinguistic and phonetic characteristics of a female speaker of Belgian Dutch who suffered from neurogenic FAS in which she developed a French/German foreign accent after a left hemisphere stroke. A detailed phonetic analysis of the speaker’s pronunciation errors revealed problems at both the segmental and suprasegmental level. At the segmental level a wide variety of pronunciation errors were observed which are consistent with a tense articulatory setting: creaky voice, strengthening of fricatives into stops and more carefully articulated consonants and vowels. The data suggest that the perception of the French accent may have resulted from a combination of speech pathology features and unaffected regional pronunciation characteristics of the patient’s Standard Dutch.
In contrast to the traditional view in the literature that FAS represents a primary dysprosodic disturbance, a detailed analysis of the speaker’s intonation contours by means of the stylization method revealed the entirely correct implementation of the most common pitch contours of Standard Dutch. This unique finding shows that FAS does not by definition follow from disruption of prosodic processing. However, the frequency of occurrence of the different types of pitch contours was clearly deviant since the patient very frequently used the Dutch continuation rise. It is hypothesized that this might represent a deliberate strategy of the speaker to stay in control of the speaking situation by keeping the speaking turn which she is at continuous risk of losing as the result of long and frequent pausing
Biphasic Oxidation of Oxy-Hemoglobin in Bloodstains
Background: In forensic science, age determination of bloodstains can be crucial in reconstructing crimes. Upon exiting the body, bloodstains transit from bright red to dark brown, which is attributed to oxidation of oxy-hemoglobin (HbO2) to methemoglobin (met-Hb) and hemichrome (HC). The fractions of HbO 2, met-Hb and HC in a bloodstain can be used for age determination of bloodstains. In this study, we further analyze the conversion of HbO2 to met-Hb and HC, and determine the effect of temperature and humidity on the conversion rates. Methodology: The fractions of HbO2, met-Hb and HC in a bloodstain, as determined by quantitative analysis of optical reflectance spectra (450–800 nm), were measured as function of age, temperature and humidity. Additionally, Optical Coherence Tomography around 1300 nm was used to confirm quantitative spectral analysis approach. Conclusions: The oxidation rate of HbO2 in bloodstains is biphasic. At first, the oxidation of HbO2 is rapid, but slows down after a few hours. These oxidation rates are strongly temperature dependent. However, the oxidation of HbO2 seems to be independent of humidity, whereas the transition of met-Hb into HC strongly depends on humidity. Knowledge of these decay rates is indispensable for translating laboratory results into forensic practice, and to enable bloodstain age determination on the crime scene
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