39 research outputs found

    Cotangent bundle quantization: Entangling of metric and magnetic field

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    For manifolds M\cal M of noncompact type endowed with an affine connection (for example, the Levi-Civita connection) and a closed 2-form (magnetic field) we define a Hilbert algebra structure in the space L2(TM)L^2(T^*\cal M) and construct an irreducible representation of this algebra in L2(M)L^2(\cal M). This algebra is automatically extended to polynomial in momenta functions and distributions. Under some natural conditions this algebra is unique. The non-commutative product over TMT^*\cal M is given by an explicit integral formula. This product is exact (not formal) and is expressed in invariant geometrical terms. Our analysis reveals this product has a front, which is described in terms of geodesic triangles in M\cal M. The quantization of δ\delta-functions induces a family of symplectic reflections in TMT^*\cal M and generates a magneto-geodesic connection Γ\Gamma on TMT^*\cal M. This symplectic connection entangles, on the phase space level, the original affine structure on M\cal M and the magnetic field. In the classical approximation, the 2\hbar^2-part of the quantum product contains the Ricci curvature of Γ\Gamma and a magneto-geodesic coupling tensor.Comment: Latex, 38 pages, 5 figures, minor correction

    Mitotic Illegitimate Recombination Is a Mechanism for Novel Changes in High-Molecular-Weight Glutenin Subunits in Wheat-Rye Hybrids

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    Wide hybrids can have novel traits or changed expression of a quantitative trait that their parents do not have. These phenomena have long been noticed, yet the mechanisms are poorly understood. High-molecular-weight glutenin subunits (HMW-GS) are seed storage proteins encoded by Glu-1 genes that only express in endosperm in wheat and its related species. Novel HMW-GS compositions have been observed in their hybrids. This research elucidated the molecular mechanisms by investigating the causative factors of novel HMW-GS changes in wheat-rye hybrids. HMW-GS compositions in the endosperm and their coding sequences in the leaves of F1 and F2 hybrids between wheat landrace Shinchunaga and rye landrace Qinling were investigated. Missing and/or additional novel HMW-GSs were observed in the endosperm of 0.5% of the 2078 F1 and 22% of 36 F2 hybrid seeds. The wildtype Glu-1Ax null allele was found to have 42 types of short repeat sequences of 3-60 bp long that appeared 2 to 100 times. It also has an in-frame stop codon in the central repetitive region. Analyzing cloned allele sequences of HMW-GS coding gene Glu-1 revealed that deletions involving the in-frame stop codon had happened, resulting in novel ∼1.8-kb Glu-1Ax alleles in some F1 and F2 plants. The cloned mutant Glu-1Ax alleles were expressed in Escherichia coli, and the HMW-GSs produced matched the novel HMW-GSs found in the hybrids. The differential changes between the endosperm and the plant of the same hybrids and the data of E. coli expression of the cloned deletion alleles both suggested that mitotic illegitimate recombination between two copies of a short repeat sequence had resulted in the deletions and thus the changed HMW-GS compositions. Our experiments have provided the first direct evidence to show that mitotic illegitimate recombination is a mechanism that produces novel phenotypes in wide hybrids

    Prognostic model to predict postoperative acute kidney injury in patients undergoing major gastrointestinal surgery based on a national prospective observational cohort study.

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    Background: Acute illness, existing co-morbidities and surgical stress response can all contribute to postoperative acute kidney injury (AKI) in patients undergoing major gastrointestinal surgery. The aim of this study was prospectively to develop a pragmatic prognostic model to stratify patients according to risk of developing AKI after major gastrointestinal surgery. Methods: This prospective multicentre cohort study included consecutive adults undergoing elective or emergency gastrointestinal resection, liver resection or stoma reversal in 2-week blocks over a continuous 3-month period. The primary outcome was the rate of AKI within 7 days of surgery. Bootstrap stability was used to select clinically plausible risk factors into the model. Internal model validation was carried out by bootstrap validation. Results: A total of 4544 patients were included across 173 centres in the UK and Ireland. The overall rate of AKI was 14·2 per cent (646 of 4544) and the 30-day mortality rate was 1·8 per cent (84 of 4544). Stage 1 AKI was significantly associated with 30-day mortality (unadjusted odds ratio 7·61, 95 per cent c.i. 4·49 to 12·90; P < 0·001), with increasing odds of death with each AKI stage. Six variables were selected for inclusion in the prognostic model: age, sex, ASA grade, preoperative estimated glomerular filtration rate, planned open surgery and preoperative use of either an angiotensin-converting enzyme inhibitor or an angiotensin receptor blocker. Internal validation demonstrated good model discrimination (c-statistic 0·65). Discussion: Following major gastrointestinal surgery, AKI occurred in one in seven patients. This preoperative prognostic model identified patients at high risk of postoperative AKI. Validation in an independent data set is required to ensure generalizability

    Mobile Applications and Wearables for Chronic Respiratory Disease Monitoring

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    Mobile health (mHealth) has tremendous potential to benefit patients, providers, and the entire healthcare system. Benefits for patients to adopt mHealth include more effective access to health providers, reduced costs of care, and better health control. For physicians and the healthcare system, reasons to embrace mHealth are enhanced health outcomes, facilitated access to patients for care, and decreased time required for administrative tasks. Currently, some mobile apps and wearables dedicated to respiratory health provide medical education and messaging services, enable diary logs, aid with disease self-management, and include educational games. Major challenges for mHealth to be widely adopted include lack of studies demonstrating effectiveness, limited access to technology by all patients, decreased adoption over time, high costs, and data privacy concerns

    Acute exercise leads to regulation of Telomere-Associated genes and MicroRNA expression in immune Cells

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    Telomeres are specialized nucleoprotein structures that protect chromosomal ends from degradation. These structures progressively shorten during cellular division and can signal replicative senescence below a critical length. Telomere length is predominantly maintained by the enzyme telomerase. Significant decreases in telomere length and telomerase activity are associated with a host of chronic diseases; conversely their maintenance underpins the optimal function of the adaptive immune system. Habitual physical activity is associated with longer leukocyte telomere length; however, the precise mechanisms are unclear. Potential hypotheses include regulation of telomeric gene transcription and/or microRNAs (miRNAs). We investigated the acute exercise-induced response of telomeric genes and miRNAs in twenty-two healthy males (mean age = 24.1±1.55 years). Participants undertook 30 minutes of treadmill running at 80% of peak oxygen uptake. Blood samples were taken before exercise, immediately post-exercise and 60 minutes post-exercise. Total RNA from white blood cells was submitted to miRNA arrays and telomere extension mRNA array. Results were individually validated in white blood cells and sorted T cell lymphocyte subsets using quantitative real-time PCR (qPCR). Telomerase reverse transcriptase (TERT) mRNA (P = 0.001) and sirtuin-6 (SIRT6) (P<0.05) mRNA expression were upregulated in white blood cells after exercise. Fifty-six miRNAs were also differentially regulated post-exercise (FDR <0.05). In silico analysis identified four miRNAs (miR-186, miR-181, miR-15a and miR-96) that potentially targeted telomeric gene mRNA. The four miRNAs exhibited significant upregulation 60 minutes post-exercise (P<0.001). Telomeric repeat binding factor 2, interacting protein (TERF2IP) was identified as a potential binding target for miR-186 and miR-96 and demonstrated concomitant downregulation (P<0.01) at the corresponding time point. Intense cardiorespiratory exercise was sufficient to differentially regulate key telomeric genes and miRNAs in white blood cells. These results may provide a mechanistic insight into telomere homeostasis and improved immune function and physical health. Funding NHMR
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