11,170 research outputs found
Tachyon Kinks in Boundary String Field Theory
We study tachyon kinks with and without electromagnetic fields in the context
of boundary string field theory. For the case of pure tachyon only an array of
kink-antikink is obtained. In the presence of electromagnetic coupling, all
possible static codimension-one soliton solutions such as array of
kink-antikink, single topological BPS kink, bounce, half kink, as well as
nonBPS topological kink are found, and their properties including the
interpretation as branes are analyzed in detail. Spectrum of the obtained kinks
coincides with that of Dirac-Born-Infeld type effective theory.Comment: LaTex, 29 pages, 17 Figure
β-catenin activation down-regulates cell-cell junction-related genes and induces epithelial-to-mesenchymal transition in colorectal cancers
WNT signaling activation in colorectal cancers (CRCs) occurs through APC inactivation or β-catenin mutations. Both processes promote β-catenin nuclear accumulation, which up-regulates epithelial-to-mesenchymal transition (EMT). We investigated β-catenin localization, transcriptome, and phenotypic differences of HCT116 cells containing a wild-type (HCT116-WT) or mutant β-catenin allele (HCT116-MT), or parental cells with both WT and mutant alleles (HCT116-P). We then analyzed β-catenin expression and associated phenotypes in CRC tissues. Wild-type β-catenin showed membranous localization, whereas mutant showed nuclear localization; both nuclear and non-nuclear localization were observed in HCT116-P. Microarray analysis revealed down-regulation of Claudin-7 and E-cadherin in HCT116-MT vs. HCT116-WT. Claudin-7 was also down-regulated in HCT116-P vs. HCT116-WT without E-cadherin dysregulation. We found that ZEB1 is a critical EMT factor for mutant β-catenin-mediated loss of E-cadherin and Claudin-7 in HCT116-P and HCT116-MT cells. We also demonstrated that E-cadherin binds to both WT and mutant β-catenin, and loss of E-cadherin releases β-catenin from the cell membrane and leads to its degradation. Alteration of Claudin-7, as well as both Claudin-7 and E-cadherin respectively caused tight junction (TJ) impairment in HCT116-P, and dual loss of TJs and adherens junctions (AJs) in HCT116-MT. TJ loss increased cell motility, and subsequent AJ loss further up-regulated that. Immunohistochemistry analysis of 101 CRCs revealed high (14.9%), low (52.5%), and undetectable (32.6%) β-catenin nuclear expression, and high β-catenin nuclear expression was significantly correlated with overall survival of CRC patients (P = 0.009). Our findings suggest that β-catenin activation induces EMT progression by modifying cell-cell junctions, and thereby contributes to CRC aggressiveness
Work function seen with sub-meV precision through laser photoemission
Electron emission can be utilised to measure the work function of the
surface. However, the number of significant digits in the values obtained
through thermionic-, field- and photo-emission techniques is typically just two
or three. Here, we show that the number can go up to five when angle-resolved
photoemission spectroscopy (ARPES) is applied. This owes to the capability of
ARPES to detect the slowest photoelectrons that are directed only along the
surface normal. By using a laser-based source, we optimised our setup for the
slow photoelectrons and resolved the slowest-end cutoff of Au(111) with the
sharpness not deteriorated by the bandwidth of light nor by Fermi-Dirac
distribution. The work function was leveled within 0.4 meV at least from
30 to 90 K and the surface aging was discerned as a meV shift of the work
function. Our study opens the investigations into the fifth significant digit
of the work function.Comment: For an associated blog-type posting, see
https://devicematerialscommunity.nature.com/posts/measuring-the-work-function-precisely-by-using-laser-arpe
Expression of osteopontin in calcified coronary atherosclerotic plaques.
Advanced atherosclerosis is often associated with dystrophic calcification and remodeling of extracellular matrix of vascular wall. Recently many studies have documented a general relationship between calcification and severity of coronary disease, and discussed the feasibility of electron beam computed tomography for detecting and quantifying the coronary artery calcification in the patients. The present study investigated the expression and the localization of osteopontin, one of noncollagenous bone matrix protein, within the calcified coronary arteries. Autopsy-derived coronary artery specimens were scanned and reconstructed to visualize the pattern of coronary calcification using a novel microscopic computed tomography technique. The localization of the osteopontin were evaluated by immunohistochemial stain with LF7. The present study showed that the pattern of coronary calcification is variable and the expression of osteopontin is localized mainly to calcified lesion. The smooth muscle cells in addition to macrophage expressed osteopontin protein in human coronary atherosclerotic plaques. Soluble osteopontin released near to the sites of vascular calcification may represent an adaptive mechanism aimed at regulating the process of vascular calcification
Negative modes in the four-dimensional stringy wormholes
We study the Giddings-Strominger wormholes in string theories. We found
negative modes among O(4)-symmetric fluctuations about the non-singular
wormhole background. Hence the stringy wormhole contribution to the euclidean
functional integral is purely imaginary. This means that the stringy wormhole
is a bounce (not an instanton) and describes the nucleation and growth of
wormholes in the Minkowski spacetime.Comment: 12 pages 2 figures, RevTe
Phosphate uptake and growth characteristics of transgenic rice with phosphate transporter 1 (OsPT1) gene overexpression under high phosphate soils
Farmers have used phosphate fertilizer to provide sufficient yields. However, overuse of phosphorus accumulate in soil and causes soil and water pollution. We evaluated the phosphate acquisition and growth characteristics of OsPT1 transgenic rice (OsPT1-OX, over-expressing the high affinity phosphate transporter 1) in high phosphate soils with different level of nitrogen fertilizer treatment to investigate its removal ability of excessive phosphate from soil. OsPT1-OX had shorter culm length but more tillers than those of wild-type plants in each soil conditions. Phosphate content per dry weight of OsPT1-OX was 1.8 times higher than that of wild-type under control fertilizer treated conditions. Although the dry weight of OsPT1-OX was not different from that of wild-type plants, whole plant phosphate content was 1.7 times higher than that of wild-type plants under control fertilizer conditions. Tiller number and phosphate content per dry weight of wild-type plants increased following high levels of phosphate application, but did not change following additional nitrogen application. Tiller number and phosphate content per dry weight of OsPT1-OX did not also change under the high phosphate condition, but increased following nitrogen application under similar conditions. Whole plant phosphate content was also highest under high nitrogen and high phosphate application conditions. These results suggest that OsPT1-OX may reduce phosphate content in soils containing excess phosphate and may be further effective under high nitrogen condition.Key words: Phosphate content, fertilizer treatment, phosphate transporter, rice, soil
Defects Detection in GFRP Composites by using Transmission method of Infrared Thermography
Abstract In this study, infrared thermography measurement technique has been used to defect detection of composite materials which is widely used in aerospace and wind turbine blades. To increase the defect detection rate, the related experiment used the lock-in IR-thermography method. Unlike the existing reflection method, transmission method that halogen lamp is located behind the specimen has been used to defect detection. The results show that the possibility of detecting defects gets higher than using the transmission method. Infrared thermography images show that all detection of composite material specimen is detected through overall section From 50 mHz to 400 mHz
Status and performance of the AMoRE-I experiment on neutrinoless double beta decay
AMoRE is an international project to search for the neutrinoless double beta
decay of Mo using a detection technology consisting of magnetic
microcalorimeters (MMCs) and molybdenum-based scintillating crystals. Data
collection has begun for the current AMORE-I phase of the project, an upgrade
from the previous pilot phase. AMoRE-I employs thirteen
CaMoO crystals and five LiMoO
crystals for a total crystal mass of 6.2 kg. Each detector module contains a
scintillating crystal with two MMC channels for heat and light detection. We
report the present status of the experiment and the performance of the detector
modules.Comment: 8 pages, 4 figures, published in Journal of Low Temperature Physics
(2022
Status of 48Ca double beta decay search and its future prospect in CANDLES
CANDLES(CAlcium fluoride for the study of Neutrinos and Dark matters by Low Energy Spectrometer) is the experiment to search for the neutrino-less double beta decay(0vββ) of 48Ca with CaF2 scintillator. 48Ca has the highest Qββ-value (4.3 MeV) among all isotope candidates for 0vββ. It enables us to measure signals with very low background condition. After rejection analysis with 131 days × 86 kg data for background events from radioactive contaminations in the CaF2 scintillators, no events are observed in the Qββ-value region. As a result, the 0vββ half-life of 48Ca is greater than 6.2 × 1022 yr (90% confidence level). For further high sensitive measurement of 48Ca 0vββ search, we have been developing the 48Ca enrichment and CaF2 scintillating bolometer techniques. In this paper, the latest result for CANDLES and the status of scintillating bolometer development are described
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