284 research outputs found
Observation of diurnal variations in mesoscale eddy sea-surface currents using GOCI data
The surface current field of a mesoscale eddy in the East Sea (Sea of Japan) was derived from consecutive Geostationary Ocean Color Imager chlorophyll-a (chl-a) concentration images using the normalized maximum cross-correlation method. The estimated current field of the eddy exhibited anticyclonic structure demonstrated by the objective dynamic thresholds of correlation coefficients. The eddy periphery was defined by fitting an ellipse to subjectively selected points from the frontal map of chl-a concentration data. Radial distribution and hourly variation of the current speed around the eddy were presented. In terms of the magnitude and direction, the estimated current field was in good agreement with altimeter-based current field and current vectors from surface drifters. Diurnal variations in the current speeds of the mesoscale eddies showed a quadratic relation to the wind speed
Surface currents from hourly variations of suspended particulate matter from Geostationary Ocean Color Imager data
Surface currents in Korean coastal regions were obtained using the maximum cross-correlation method applied to hourly suspended particulate matter images from the Geostationary Ocean Color Imager. Preliminary current vectors were filtered out by applying a series of quality-control procedures. The current vectors resulting from the tests were compared with the currents from a numerical model with tide and wind field. It was found that the estimated currents were more similarly to the currents caused by both tide and wind. A high degree of discrepancy was detected in regions of strong tidal currents, where the fundamental assumption of horizontal movement was limited due to the dominant vertical tidal mixing in the shallow region. The hourly rotations of the current vectors within a day were clarified by a comparison of the time-varying orientation angles of tidal ellipses. This study emphasized how to understand the short-term surface flows from hourly high-resolution geostationary satellite images
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Immersive bilingualism reshapes the core of the brain
Bilingualism has been shown to affect the structure of the brain, including cortical regions related to language. Less is known about subcortical structures, such as the basal ganglia, which underlie speech monitoring and language selection, processes that are crucial for bilinguals, as well as other linguistic functions, such as grammatical and phonological acquisition and processing. Simultaneous bilinguals have demonstrated significant reshaping of the basal ganglia and the thalamus compared to monolinguals. However, it is not clear whether these effects are due to learning of the second language (L2) at a very young age or simply due to continuous usage of two languages. Here, we show that bilingualism-induced subcortical effects are directly related to the amount of continuous L2 usage, or L2 immersion. We found significant subcortical reshaping in non-simultaneous (or sequential) bilinguals with extensive immersion in a bilingual environment, closely mirroring the recent findings in simultaneous bilinguals. Importantly, some of these effects were positively correlated to the amount of L2 immersion. Conversely, sequential bilinguals with comparable proficiency and age of acquisition (AoA) but limited immersion did not show similar effects. Our results provide structural evidence to suggestions that L2 acquisition continuously occurs in an immersive environment, and is expressed as dynamic reshaping of the core of the brain. These findings propose that second language learning in the brain is a dynamic procedure which depends on active and continuous L2 usage
A922 Sequential measurement of 1 hour creatinine clearance (1-CRCL) in critically ill patients at risk of acute kidney injury (AKI)
Meeting abstrac
Orientation Sensitivity at Different Stages of Object Processing: Evidence from Repetition Priming and Naming
An ongoing debate in the object recognition literature centers on whether the shape representations used in recognition are coded in an orientation-dependent or orientation-invariant manner. In this study, we asked whether the nature of the object representation (orientation-dependent vs orientation-invariant) depends on the information-processing stages tapped by the task
Phase 1 dose de-escalation trial of the endogenous folate [6R]-5,10-methylene tetrahydrofolate in combination with fixed-dose pemetrexed as neoadjuvant therapy in patients with resectable rectal cancer
Applying unmixing to gene expression data for tumor phylogeny inference
<p>Abstract</p> <p>Background</p> <p>While in principle a seemingly infinite variety of combinations of mutations could result in tumor development, in practice it appears that most human cancers fall into a relatively small number of "sub-types," each characterized a roughly equivalent sequence of mutations by which it progresses in different patients. There is currently great interest in identifying the common sub-types and applying them to the development of diagnostics or therapeutics. Phylogenetic methods have shown great promise for inferring common patterns of tumor progression, but suffer from limits of the technologies available for assaying differences between and within tumors. One approach to tumor phylogenetics uses differences between single cells within tumors, gaining valuable information about intra-tumor heterogeneity but allowing only a few markers per cell. An alternative approach uses tissue-wide measures of whole tumors to provide a detailed picture of averaged tumor state but at the cost of losing information about intra-tumor heterogeneity.</p> <p>Results</p> <p>The present work applies "unmixing" methods, which separate complex data sets into combinations of simpler components, to attempt to gain advantages of both tissue-wide and single-cell approaches to cancer phylogenetics. We develop an unmixing method to infer recurring cell states from microarray measurements of tumor populations and use the inferred mixtures of states in individual tumors to identify possible evolutionary relationships among tumor cells. Validation on simulated data shows the method can accurately separate small numbers of cell states and infer phylogenetic relationships among them. Application to a lung cancer dataset shows that the method can identify cell states corresponding to common lung tumor types and suggest possible evolutionary relationships among them that show good correspondence with our current understanding of lung tumor development.</p> <p>Conclusions</p> <p>Unmixing methods provide a way to make use of both intra-tumor heterogeneity and large probe sets for tumor phylogeny inference, establishing a new avenue towards the construction of detailed, accurate portraits of common tumor sub-types and the mechanisms by which they develop. These reconstructions are likely to have future value in discovering and diagnosing novel cancer sub-types and in identifying targets for therapeutic development.</p
Growth Hormone Promotes Hair Cell Regeneration in the Zebrafish (Danio rerio) Inner Ear following Acoustic Trauma
BACKGROUND: Previous microarray analysis showed that growth hormone (GH) was significantly upregulated following acoustic trauma in the zebrafish (Danio rerio) ear suggesting that GH may play an important role in the process of auditory hair cell regeneration. Our objective was to examine the effects of exogenous and endogenous GH on zebrafish inner ear epithelia following acoustic trauma. METHODOLOGY/PRINCIPAL FINDINGS: We induced auditory hair cell damage by exposing zebrafish to acoustic overstimulation. Fish were then injected intraperitoneally with either carp GH or buffer, and placed in a recovery tank for either one or two days. Phalloidin-, bromodeoxyuridine (BrdU)-, and TUNEL-labeling were used to examine hair cell densities, cell proliferation, and apoptosis, respectively. Two days post-trauma, saccular hair cell densities in GH-treated fish were similar to that of baseline controls, whereas buffer-injected fish showed significantly reduced densities of hair cell bundles. Cell proliferation was greater and apoptosis reduced in the saccules, lagenae, and utricles of GH-treated fish one day following trauma compared to controls. Fluorescent in situ hybridization (FISH) was used to examine the localization of GH mRNA in the zebrafish ear. At one day post-trauma, GH mRNA expression appeared to be localized perinuclearly around erythrocytes in the blood vessels of the inner ear epithelia. In order to examine the effects of endogenous GH on the process of cell proliferation in the ear, a GH antagonist was injected into zebrafish immediately following acoustic trauma, resulting in significantly decreased cell proliferation one day post-trauma in all three zebrafish inner ear end organs. CONCLUSIONS/SIGNIFICANCE: Our results show that exogenous GH promotes post-trauma auditory hair cell regeneration in the zebrafish ear through stimulating proliferation and suppressing apoptosis, and that endogenous GH signals are present in the zebrafish ear during the process of auditory hair cell regeneration
GUCY2C Opposes Systemic Genotoxic Tumorigenesis by Regulating AKT-Dependent Intestinal Barrier Integrity
The barrier separating mucosal and systemic compartments comprises epithelial cells, annealed by tight junctions, limiting permeability. GUCY2C recently emerged as an intestinal tumor suppressor coordinating AKT1-dependent crypt-villus homeostasis. Here, the contribution of GUCY2C to barrier integrity opposing colitis and systemic tumorigenesis is defined. Mice deficient in GUCY2C (Gucy2c−/−) exhibited barrier hyperpermeability associated with reduced junctional proteins. Conversely, activation of GUCY2C in mice reduced barrier permeability associated with increased junctional proteins. Further, silencing GUCY2C exacerbated, while activation reduced, chemical barrier disruption and colitis. Moreover, eliminating GUCY2C amplified, while activation reduced, systemic oxidative DNA damage. This genotoxicity was associated with increased spontaneous and carcinogen-induced systemic tumorigenesis in Gucy2c−/− mice. GUCY2C regulated barrier integrity by repressing AKT1, associated with increased junction proteins occludin and claudin 4 in mice and Caco2 cells in vitro. Thus, GUCY2C defends the intestinal barrier, opposing colitis and systemic genotoxicity and tumorigenesis. The therapeutic potential of this observation is underscored by the emerging clinical development of oral GUCY2C ligands, which can be used for chemoprophylaxis in inflammatory bowel disease and cancer
Evaluation of 22 genetic variants with Crohn's Disease risk in the Ashkenazi Jewish population: a case-control study
<p>Abstract</p> <p>Background</p> <p>Crohn's disease (CD) has the highest prevalence among individuals of Ashkenazi Jewish (AJ) descent compared to non-Jewish Caucasian populations (NJ). We evaluated a set of well-established CD-susceptibility variants to determine if they can explain the increased CD risk in the AJ population.</p> <p>Methods</p> <p>We recruited 369 AJ CD patients and 503 AJ controls, genotyped 22 single nucleotide polymorphisms (SNPs) at or near 10 CD-associated genes, <it>NOD2</it>, <it>IL23R</it>, <it>IRGM</it>, <it>ATG16L1</it>, <it>PTGER4</it>, <it>NKX2-3</it>, <it>IL12B</it>, <it>PTPN2</it>, <it>TNFSF15 </it>and <it>STAT3</it>, and assessed their association with CD status. We generated genetic scores based on the risk allele count alone and the risk allele count weighed by the effect size, and evaluated their predictive value.</p> <p>Results</p> <p>Three <it>NOD2 </it>SNPs, two <it>IL23R </it>SNPs, and one SNP each at <it>IRGM </it>and <it>PTGER4 </it>were independently associated with CD risk. Carriage of 7 or more copies of these risk alleles or the weighted genetic risk score of 7 or greater correctly classified 92% (allelic count score) and 83% (weighted score) of the controls; however, only 29% and 47% of the cases were identified as having the disease, respectively. This cutoff was associated with a >4-fold increased disease risk (p < 10e-16).</p> <p>Conclusions</p> <p>CD-associated genetic risks were similar to those reported in NJ population and are unlikely to explain the excess prevalence of the disease in AJ individuals. These results support the existence of novel, yet unidentified, genetic variants unique to this population. Understanding of ethnic and racial differences in disease susceptibility may help unravel the pathogenesis of CD leading to new personalized diagnostic and therapeutic approaches.</p
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