202 research outputs found
Lambda and Antilambda polarization from deep inelastic muon scattering
We report results of the first measurements of Lambda and Antilambda
polarization produced in deep inelastic polarized muon scattering on the
nucleon. The results are consistent with an expected trend towards positive
polarization with increasing x_F. The polarizations of Lambda and Antilambda
appear to have opposite signs. A large negative polarization for Lambda at low
positive x_F is observed and is not explained by existing models.A possible
interpretation is presented.Comment: 9 pages, 2 figure
Chronic ventricular pacing in children: toward prevention of pacing-induced heart disease
In children with congenital or acquired complete atrioventricular (AV) block, ventricular pacing is indicated to increase heart rate. Ventricular pacing is highly beneficial in these patients, but an important side effect is that it induces abnormal electrical activation patterns. Traditionally, ventricular pacemaker leads are positioned at the right ventricle (RV). The dyssynchronous pattern of ventricular activation due to RV pacing is associated with an acute and chronic impairment of left ventricular (LV) function, structural remodeling of the LV, and increased risk of heart failure. Since the degree of pacing-induced dyssynchrony varies between the different pacing sites, βoptimal-site pacingβ should aim at the prevention of mechanical dyssynchrony. Especially in children, generally paced from a very early age and having a perspective of life-long pacing, the preservation of cardiac function during chronic ventricular pacing should take high priority. In the perspective of the (patho)physiology of ventricular pacing and the importance of the sequence of activation, this paper provides an overview of the current knowledge regarding possible alternative sites for chronic ventricular pacing. Furthermore, clinical implications and practical concerns of the various pacing sites are discussed. The review concludes with recommendations for optimal-site pacing in children
Optimization of Energy-Consuming Pathways towards Rapid Growth in HPV-Transformed Cells
Cancer is a complex, multi-step process characterized by misregulated signal transduction and altered metabolism. Cancer cells divide faster than normal cells and their growth rates have been reported to correlate with increased metabolic flux during cell transformation. Here we report on progressive changes in essential elements of the biochemical network, in an in vitro model of transformation, consisting of primary human keratinocytes, human keratinocytes immortalized by human papillomavirus 16 (HPV16) and passaged repeatedly in vitro, and the extensively-passaged cells subsequently treated with the carcinogen benzo[a]pyrene. We monitored changes in cell growth, cell size and energy metabolism. The more transformed cells were smaller and divided faster, but the cellular energy flux was unchanged. During cell transformation the protein synthesis network contracted, as shown by the reduction in key cap-dependent translation factors. Moreover, there was a progressive shift towards internal ribosome entry site (IRES)-dependent translation. The switch from cap to IRES-dependent translation correlated with progressive activation of c-Src, an activator of AMP-activated protein kinase (AMPK), which controls energy-consuming processes, including protein translation. As cellular protein synthesis is a major energy-consuming process, we propose that the reduction in cell size and protein amount provide energy required for cell survival and proliferation. The cap to IRES-dependent switch seems to be part of a gradual optimization of energy-consuming mechanisms that redirects cellular processes to enhance cell growth, in the course of transformation
In-play sports betting: a scoping study
Technology has changed the nature of gambling practices over the last decade and is continuing to do so. The online sports betting industry has become a rapidly growing sector of the global economy, with online sports betting contributing 37% of the annual online gambling market in Europe. There has been an integration of social and technological processes that has enabled the cultural saliency of contemporary online betting. One of the more newly introduced forms of online sports betting is in-play sports betting behaviour (the betting on events within a sporting event such as football and cricket). In-play sports betting features (such as 'cash out') are increasing in popularity amongst online gambling operators. A scoping study was carried out examining the evolution of this new form of gambling practice which included both a systematic literature review and the examination of 338 online gambling websites that offered sports betting. The present study identified a comprehensive list of what in-play betting features are currently being offered on online gambling websites as well as other information concerning in-play sports betting. A total of 16 academic papers and two 'grey literature' reports and were identified in the systematic review. Out of 338 online gambling websites that were visited, 26% of these offered at least on in-play betting feature. Results from the systematic review suggest that in-play sports betting has the potential to be more harmful than other ways of gambling because of the inherent structural characteristics
In-play sports betting: a scoping study
Technology has changed the nature of gambling practices over the last decade and is continuing to do so. The online sports betting industry has become a rapidly growing sector of the global economy, with online sports betting contributing 37% of the annual online gambling market in Europe. There has been an integration of social and technological processes that has enabled the cultural saliency of contemporary online betting. One of the more newly introduced forms of online sports betting is in-play sports betting behaviour (the betting on events within a sporting event such as football and cricket). In-play sports betting features (such as 'cash out') are increasing in popularity amongst online gambling operators. A scoping study was carried out examining the evolution of this new form of gambling practice which included both a systematic literature review and the examination of 338 online gambling websites that offered sports betting. The present study identified a comprehensive list of what in-play betting features are currently being offered on online gambling websites as well as other information concerning in-play sports betting. A total of 16 academic papers and two 'grey literature' reports and were identified in the systematic review. Out of 338 online gambling websites that were visited, 26% of these offered at least on in-play betting feature. Results from the systematic review suggest that in-play sports betting has the potential to be more harmful than other ways of gambling because of the inherent structural characteristics
Differences in Brain Function and Changes with Intervention in Children with Poor Spelling and Reading Abilities
Previous fMRI studies in English-speaking samples suggested that specific interventions may alter brain function in language-relevant networks in children with reading and spelling difficulties, but this research strongly focused on reading impaired individuals. Only few studies so far investigated characteristics of brain activation associated with poor spelling ability and whether a specific spelling intervention may also be associated with distinct changes in brain activity patterns. We here investigated such effects of a morpheme-based spelling intervention on brain function in 20 children with comparatively poor spelling and reading abilities using repeated fMRI. Relative to 10 matched controls, children with comparatively poor spelling and reading abilities showed increased activation in frontal medial and right hemispheric regions and decreased activation in left occipito-temporal regions prior to the intervention, during processing of a lexical decision task. After five weeks of intervention, spelling and reading comprehension significantly improved in the training group, along with increased activation in the left temporal, parahippocampal and hippocampal regions. Conversely, the waiting group showed increases in right posterior regions. Our findings could indicate an increased left temporal activation associated with the recollection of the new learnt morpheme-based strategy related to successful training
Global Analysis of DNA Methylation by Methyl-Capture Sequencing Reveals Epigenetic Control of Cisplatin Resistance in Ovarian Cancer Cell
Cisplatin resistance is one of the major reasons leading to the high death rate of ovarian cancer. Methyl-Capture sequencing (MethylCap-seq), which combines precipitation of methylated DNA by recombinant methyl-CpG binding domain of MBD2 protein with NGS, global and unbiased analysis of global DNA methylation patterns. We applied MethylCap-seq to analyze genome-wide DNA methylation profile of cisplatin sensitive ovarian cancer cell line A2780 and its isogenic derivative resistant line A2780CP. We obtained 21,763,035 raw reads for the drug resistant cell line A2780CP and 18,821,061reads for the sensitive cell line A2780. We identified 1224 hyper-methylated and 1216 hypomethylated DMRs (differentially methylated region) in A2780CP compared to A2780. Our MethylCap-seq data on this ovarian cancer cisplatin resistant model provided a good resource for the research community. We also found that A2780CP, compared to A2780, has lower observed to expected methylated CpG ratios, suggesting a lower global CpG methylation in A2780CP cells. Methylation specific PCR and bisulfite sequencing confirmed hypermethylation of PTK6, PRKCE and BCL2L1 in A2780 compared with A2780CP. Furthermore, treatment with the demethylation reagent 5-aza-dC in A2780 cells demethylated the promoters and restored the expression of PTK6, PRKCE and BCL2L1
Mitochondrial Physiology and Gene Expression Analyses Reveal Metabolic and Translational Dysregulation in Oocyte-Induced Somatic Nuclear Reprogramming
While reprogramming a foreign nucleus after somatic cell nuclear transfer (SCNT), the enucleated oocyte (ooplasm) must signal that biomass and cellular requirements changed compared to the nucleus donor cell. Using cells expressing nuclear-encoded but mitochondria-targeted EGFP, a strategy was developed to directly distinguish maternal and embryonic products, testing ooplasm demands on transcriptional and post-transcriptional activity during reprogramming. Specifically, we compared transcript and protein levels for EGFP and other products in pre-implantation SCNT embryos, side-by-side to fertilized controls (embryos produced from the same oocyte pool, by intracytoplasmic injection of sperm containing the EGFP transgene). We observed that while EGFP transcript abundance is not different, protein levels are significantly lower in SCNT compared to fertilized blastocysts. This was not observed for Gapdh and Actb, whose protein reflected mRNA. This transcript-protein relationship indicates that the somatic nucleus can keep up with ooplasm transcript demands, whilst transcription and translation mismatch occurs after SCNT for certain mRNAs. We further detected metabolic disturbances after SCNT, suggesting a place among forces regulating post-transcriptional changes during reprogramming. Our observations ascribe oocyte-induced reprogramming with previously unsuspected regulatory dimensions, in that presence of functional proteins may no longer be inferred from mRNA, but rather depend on post-transcriptional regulation possibly modulated through metabolism
Structure and Novel Functional Mechanism of Drosophila SNF in Sex-Lethal Splicing
Sans-fille (SNF) is the Drosophila homologue of mammalian general splicing factors U1A and U2Bβ³, and it is essential in Drosophila sex determination. We found that, besides its ability to bind U1 snRNA, SNF can also bind polyuridine RNA tracts flanking the male-specific exon of the master switch gene Sex-lethal (Sxl) pre-mRNA specifically, similar to Sex-lethal protein (SXL). The polyuridine RNA binding enables SNF directly inhibit Sxl exon 3 splicing, as the dominant negative mutant SNF1621 binds U1 snRNA but not polyuridine RNA. Unlike U1A, both RNA recognition motifs (RRMs) of SNF can recognize polyuridine RNA tracts independently, even though SNF and U1A share very high sequence identity and overall structure similarity. As SNF RRM1 tends to self-associate on the opposite side of the RNA binding surface, it is possible for SNF to bridge the formation of super-complexes between two introns flanking Sxl exon 3 or between a intron and U1 snRNP, which serves the molecular basis for SNF to directly regulate Sxl splicing. Taken together, a new functional model for SNF in Drosophila sex determination is proposed. The key of the new model is that SXL and SNF function similarly in promoting Sxl male-specific exon skipping with SNF being an auxiliary or backup to SXL, and it is the combined dose of SXL and SNF governs Drosophila sex determination
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