916 research outputs found
A comparative examination of policy and models of disability in Korea and the UK
Over the last three decades, the understanding of disability has changed substantially, changes in theoretical debates and policy on disability now encourage society to understand and treat disabled people as ordinary citizens. However, arguably the dominance of Western theory on disability has resulted in the marginalisation of disabled people’s experiences in non Western cultures. This paper compares disability in relation to the culture of South Korea and the UK, by attempting to articulate some of the implicit values of disability and development of the relevant disability polic
ForestQC: Quality control on genetic variants from next-generation sequencing data using random forest.
Next-generation sequencing technology (NGS) enables the discovery of nearly all genetic variants present in a genome. A subset of these variants, however, may have poor sequencing quality due to limitations in NGS or variant callers. In genetic studies that analyze a large number of sequenced individuals, it is critical to detect and remove those variants with poor quality as they may cause spurious findings. In this paper, we present ForestQC, a statistical tool for performing quality control on variants identified from NGS data by combining a traditional filtering approach and a machine learning approach. Our software uses the information on sequencing quality, such as sequencing depth, genotyping quality, and GC contents, to predict whether a particular variant is likely to be false-positive. To evaluate ForestQC, we applied it to two whole-genome sequencing datasets where one dataset consists of related individuals from families while the other consists of unrelated individuals. Results indicate that ForestQC outperforms widely used methods for performing quality control on variants such as VQSR of GATK by considerably improving the quality of variants to be included in the analysis. ForestQC is also very efficient, and hence can be applied to large sequencing datasets. We conclude that combining a machine learning algorithm trained with sequencing quality information and the filtering approach is a practical approach to perform quality control on genetic variants from sequencing data
Lung Cancer Metastasis Presenting as a Solitary Skull Mass
Lung cancer has been well documented to spread to bone and the axial skeleton after metastasis to adjacent organs. Bony metastasis is not, however, the typical presenting manifestation. The differential diagnosis for a tissue mass on the skull should warrant a workup for metastatic disease. Bony metastasis plays an important role in treatment and disease management. We report an exceptionally rare case of stage IV lung adenocarcinoma that presented with a solitary skull metastasis and a significant soft-tissue component. The lesion was treated by excision via craniotomy and subsequent medical management of the adenocarcinoma. This case illustrates a very rare presentation of lung adenocarcinoma and also represents what the authors believe to be the first report of a solitary skull mass originating from a lung primary. We also present a review of the literature surrounding bony metastasis to the skull and implications for patient care
Control of mammalian G protein signaling by N-terminal acetylation and the N-end rule pathway
Rgs2, a regulator of G proteins, lowers blood pressure by decreasing signaling through Gαq. Human patients expressing Met-Leu-Rgs2 (ML-Rgs2) or Met-Arg-Rgs2 (MR-Rgs2) are hypertensive relative to people expressing wild-type Met-Gln-Rgs2 (MQ-Rgs2). We found that wild-type MQ-Rgs2 and its mutant, MR-Rgs2, were destroyed by the Ac/N-end rule pathway, which recognizes Nα-terminally acetylated (Nt-acetylated) proteins. The shortest-lived mutant, ML-Rgs2, was targeted by both the Ac/N-end rule and Arg/N-end rule pathways. The latter pathway recognizes unacetylated N-terminal residues. Thus, the Nt-acetylated Ac-MX-Rgs2 (X = Arg, Gln, Leu) proteins are specific substrates of the mammalian Ac/N-end rule pathway. Furthermore, the Ac/N-degron of Ac-MQ-Rgs2 was conditional, and Teb4, an endoplasmic reticulum (ER) membrane-embedded ubiquitin ligase, was able to regulate G protein signaling by targeting Ac-MX-Rgs2 proteins for degradation through their N^α-terminal acetyl group
Degradation of Serotonin N-Acetyltransferase, a Circadian Regulator, by the N-end Rule Pathway
Serotonin N-acetyltransferase (AANAT) converts serotonin to N-acetylserotonin (NAS), a distinct biological regulator and the immediate precursor of melatonin, a circulating hormone that influences circadian processes, including sleep. N-terminal sequences of AANAT enzymes vary among vertebrates. Mechanisms that regulate the levels of AANAT are incompletely understood. Previous findings were consistent with the possibility that AANAT may be controlled through its degradation by the N-end rule pathway. By expressing the rat and human AANATs and their mutants not only in mammalian cells but also in the yeast Saccharomyces cerevisiae, and by taking advantage of yeast genetics, we show here that two complementary forms of rat AANAT are targeted for degradation by two complementary branches of the N-end rule pathway. Specifically, the Nα terminally acetylated (Nt-acetylated) Ac-AANAT is destroyed through the recognition of its Nt acetylated N terminal Met residue by the Ac/N-end rule pathway, whereas the non Nt acetylated AANAT is targeted by the Arg/N end rule pathway, which recognizes the unacetylated N-terminal Met-Leu sequence of rat AANAT. We also show, by constructing lysine to arginine mutants of rat AANAT, that its degradation is mediated by polyubiquitylation of its Lys residue(s). Human AANAT, whose N-terminal sequence differs from that of rodent AANATs, is longer lived than its rat counterpart, and appears to be refractory to degradation by the N-end rule pathway. Together, these and related results indicate both a major involvement of the N-end rule pathway in the control of rodent AANATs and substantial differences in the regulation of rodent and human AANATs that stem from differences in their N terminal sequences
Editing of Misaminoacylated tRNA Controls the Sensitivity of Amino Acid Stress Responses in Saccharomyces cerevisiae
Amino acid starvation activates the protein kinase Gcn2p, leading to changes in gene expression and translation. Gcn2p is activated by deacylated tRNA, which accumulates when tRNA aminoacylation is limited by lack of substrates or inhibition of synthesis. Pairing of amino acids and deacylated tRNAs is catalyzed by aminoacyl-tRNA synthetases, which use quality control pathways to maintain substrate specificity. Phenylalanyl-tRNA synthetase (PheRS) maintains specificity via an editing pathway that targets non-cognate Tyr-tRNAPhe. While the primary role of aaRS editing is to prevent misaminoacylation, we demonstrate editing of misaminoacylated tRNA is also required for detection of amino acid starvation by Gcn2p. Ablation of PheRS editing caused accumulation of Tyr-tRNAPhe (5%), but not deacylated tRNAPhe during amino acid starvation, limiting Gcn2p kinase activity and suppressing Gcn4p-dependent gene expression. While the PheRS-editing ablated strain grew 50% slower and displayed a 27-fold increase in the rate of mistranslation of Phe codons as Tyr compared to wild type, the increase in mistranslation was insufficient to activate an unfolded protein stress response. These findings show that during amino acid starvation a primary role of aaRS quality control is to help the cell mount an effective stress response, independent of the role of editing in maintaining translational accuracy
Spatial assessments in texture analysis: what the radiologist needs to know
To date, studies investigating radiomics-based predictive models have tended to err on the side of data-driven or exploratory analysis of many thousands of extracted features. In particular, spatial assessments of texture have proven to be especially adept at assessing for features of intratumoral heterogeneity in oncologic imaging, which likewise may correspond with tumor biology and behavior. These spatial assessments can be generally classified as spatial filters, which detect areas of rapid change within the grayscale in order to enhance edges and/or textures within an image, or neighborhood-based methods, which quantify gray-level differences of neighboring pixels/voxels within a set distance. Given the high dimensionality of radiomics datasets, data dimensionality reduction methods have been proposed in an attempt to optimize model performance in machine learning studies; however, it should be noted that these approaches should only be applied to training data in order to avoid information leakage and model overfitting. While area under the curve of the receiver operating characteristic is perhaps the most commonly reported assessment of model performance, it is prone to overestimation when output classifications are unbalanced. In such cases, confusion matrices may be additionally reported, whereby diagnostic cut points for model predicted probability may hold more clinical significance to clinical colleagues with respect to related forms of diagnostic testing
Pediatric Phantom Dosimetry of the Portable Handheld Xray2Go
Purpose: The purpose of our study was to quantify radiation dose from the XTG
(Xray2Go) Handheld X-ray device for bitewing and anterior occlusal projections using a
pediatric phantom. The aim was to evaluate thyroid shielding effects on effective dose (E), tissue equivalent doses (HT), and assess operator backscatter radiation.
Methods: A pediatric phantom with 24 tissue site dosimeters was exposed to radiation from the Xray2Go. Projections included: Right and left bitewing (BW) without thyroid collar on phantom, BW with thyroid collar, maxillary anterior occlusal (AO) without thyroid collar, AO with thyroid collar. New dosimeters were used for each projection type, for 30 exposures. Operator wore dosimeters on forehead and right hand to quantify backscatter. Average values of HT and E were calculated.
Results: Thyroid shielding produced a statistically significant difference for posterior bitewing projections at thyroid (P<.001), lymphatic nodes (P=.04), and muscle (P=.04). Operator dose from the XTG was indistinguishable from background radiation. Conclusions: Mean effective dose was less than 1 μSv for all projections. Thyroid shielding made a statistically significant difference for radiation dose with the Xray2Go for several tissue locations and for posterior bitewings effective dose. Radiation to the operator was low and indistinguishable from background radiation
Function of Arabidopsis hexokinase-like1 as a negative regulator of plant growth
A recent analysis of the hexokinase (HXK) gene family from Arabidopsis revealed that three hexokinase-like (HKL) proteins lack catalytic activity, but share about 50% identity with the primary glucose (glc) sensor/transducer protein AtHXK1. Since the AtHKL1 protein is predicted to bind glc, although with a relatively decreased affinity, a reverse genetics approach was used to test whether HKL1 might have a related regulatory function in plant growth. By comparing phenotypes of an HKL1 mutant (hkl1-1), an HXK1 mutant (gin2-1), and transgenic lines that overexpress HKL1 in either wild-type or gin2-1 genetic backgrounds, it is shown that HKL1 is a negative effector of plant growth. Interestingly, phenotypes of HKL1 overexpression lines are generally very similar to those of gin2-1. These are quantified, in part, as reduced seedling sensitivity to high glc concentrations and reduced seedling sensitivity to auxin-induced lateral root formation. However, commonly recognized targets of glc signalling are not apparently altered in any of the HKL1 mutant or transgenic lines. In fact, most, but not all, of the observed phenotypes associated with HKL1 overexpression occur independently of the presence of HXK1 protein. The data indicate that HKL1 mediates cross-talk between glc and other plant hormone response pathways. It is also considered Whether a possibly decreased glc binding affinity of HKL1 could possibly be a feedback mechanism to limit plant growth in the presence of excessive carbohydrate availability is further considered
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