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544 result(s) for "Pan, Y.-C."
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Swope Supernova Survey 2017a (SSS17a), the optical counterpart to a gravitational wave source
On 17 August 2017, the Laser Interferometer Gravitational-Wave Observatory (LIGO) and the Virgo interferometer detected gravitational waves (GWs) emanating from a binary neutron star merger, GW170817. Nearly simultaneously, the Fermi and INTEGRAL (INTErnational Gamma-Ray Astrophysics Laboratory) telescopes detected a gamma-ray transient, GRB 170817A. At 10.9 hours after the GW trigger, we discovered a transient and fading optical source, Swope Supernova Survey 2017a (SSS17a), coincident with GW170817. SSS17a is located in NGC 4993, an S0 galaxy at a distance of 40 megaparsecs. The precise location of GW170817 provides an opportunity to probe the nature of these cataclysmic events by combining electromagnetic and GW observations.
Hypoxic lung cancer-secreted exosomal miR-23a increased angiogenesis and vascular permeability by targeting prolyl hydroxylase and tight junction protein ZO-1
Hypoxia plays a critical role during the evolution of malignant cells and tumour microenvironment (TME).Tumour-derived exosomes contain informative microRNAs involved in the interaction of cancer and stromal cells, thus contributing to tissue remodelling of tumour microenvironment. This study aims to clarify how hypoxia affects tumour angiogenesis through exosomes shed from lung cancer cells. Lung cancer cells produce more exosomes under hypoxic conditions than do parental cells under normoxic conditions. miR-23a was significantly upregulated in exosomes from lung cancer under hypoxic conditions. Exosomal miR-23a directly suppressed its target prolyl hydroxylase 1 and 2 (PHD1 and 2), leading to the accumulation of hypoxia-inducible factor-1 α (HIF-1 α) in endothelial cells. Consequently, hypoxic lung cancer cells enhanced angiogenesis by exosomes derived from hypoxic cancer under both normoxic and hypoxic conditions. In addition, exosomal miR-23a also inhibits tight junction protein ZO-1, thereby increasing vascular permeability and cancer transendothelial migration. Inhibition of miR-23a by inhibitor administration decreased angiogenesis and tumour growth in a mouse model. Furthermore, elevated levels of circulating miR-23a are found in the sera of lung cancer patients, and miR-23a levels are positively correlated with proangiogenic activities. Taken together, our study reveals the clinical relevance and prognostic value of cancer-derived exosomal miR-23a under hypoxic conditions, and investigates a unique intercellular communication, mediated by cancer-derived exosomes, which modulates tumour vasculature.
Electromagnetic evidence that SSS17a is the result of a binary neutron star merger
Eleven hours after the detection of gravitational wave source GW170817 by the Laser Interferometer Gravitational-Wave Observatory and Virgo Interferometers, an associated optical transient, SSS17a, was identified in the galaxy NGC 4993. Although the gravitational wave data indicate that GW170817 is consistent with the merger of two compact objects, the electromagnetic observations provide independent constraints on the nature of that system. We synthesize the optical to near-infrared photometry and spectroscopy of SSS17a collected by the One-Meter Two-Hemisphere collaboration, finding that SSS17a is unlike other known transients. The source is best described by theoretical models of a kilonova consisting of radioactive elements produced by rapid neutron capture (the r-process). We conclude that SSS17a was the result of a binary neutron star merger, reinforcing the gravitational wave result.
Early spectra of the gravitational wave source GW170817
On 17 August 2017, Swope Supernova Survey 2017a (SSS17a) was discovered as the optical counterpart of the binary neutron star gravitational wave event GW170817. We report time-series spectroscopy of SSS17a from 11.75 hours until 8.5 days after the merger. Over the first hour of observations, the ejecta rapidly expanded and cooled. Applying blackbody fits to the spectra, we measured the photosphere cooling from 11,000 − 900 + 3400 to 9300 − 300 + 300 kelvin, and determined a photospheric velocity of roughly 30% of the speed of light. The spectra of SSS17a began displaying broad features after 1.46 days and evolved qualitatively over each subsequent day, with distinct blue (early-time) and red (late-time) components. The late-time component is consistent with theoretical models of r-process–enriched neutron star ejecta, whereas the blue component requires high-velocity, lanthanide-free material.
Light curves of the neutron star merger GW170817/SSS17a
On 17 August 2017, gravitational waves (GWs) were detected from a binary neutron star merger, GW170817, along with a coincident short gamma-ray burst, GRB 170817A. An optical transient source, Swope Supernova Survey 17a (SSS17a),was subsequently identified as the counterpart of this event. We present ultraviolet, optical, and infrared light curves of SSS17a extending from 10.9 hours to 18 days postmerger. We constrain the radioactively powered transient resulting from the ejection of neutron-rich material. The fast rise of the light curves, subsequent decay, and rapid color evolution are consistent with multiple ejecta components of differing lanthanide abundance. The late-time light curve indicates that SSS17a produced at least ~0.05 solar masses of heavy elements, demonstrating that neutron star mergers play a role in rapid neutron capture (r-process) nucleosynthesis in the universe.
Experimental semi-autonomous eigensolver using reinforcement learning
The characterization of observables, expressed via Hermitian operators, is a crucial task in quantum mechanics. For this reason, an eigensolver is a fundamental algorithm for any quantum technology. In this work, we implement a semi-autonomous algorithm to obtain an approximation of the eigenvectors of an arbitrary Hermitian operator using the IBM quantum computer. To this end, we only use single-shot measurements and pseudo-random changes handled by a feedback loop, reducing the number of measures in the system. Due to the classical feedback loop, this algorithm can be cast into the reinforcement learning paradigm. Using this algorithm, for a single-qubit observable, we obtain both eigenvectors with fidelities over 0.97 with around 200 single-shot measurements. For two-qubits observables, we get fidelities over 0.91 with around 1500 single-shot measurements for the four eigenvectors, which is a comparatively low resource demand, suitable for current devices. This work is useful to the development of quantum devices able to decide with partial information, which helps to implement future technologies in quantum artificial intelligence.
Cognitive function and risks of cardiovascular disease and hypoglycaemia in patients with type 2 diabetes: the Action in Diabetes and Vascular Disease: Preterax and Diamicron Modified Release Controlled Evaluation (ADVANCE) trial
Aims/hypothesis The relationship between cognitive function, cardiovascular disease and premature death is not well established in patients with type 2 diabetes. We assessed the effects of cognitive function in 11,140 patients with type 2 diabetes who participated in the Action in Diabetes and Vascular Disease: Preterax and Diamicron Modified Release Controlled Evaluation (ADVANCE) trial. Furthermore, we tested whether level of cognitive function altered the beneficial effects of the BP-lowering and glycaemic-control regimens in the trial. Methods Cognitive function was assessed using the Mini Mental State Examination at baseline, and defined by scores 28-30 (‘normal', n = 8,689), 24-27 (‘mild dysfunction', n = 2,231) and <24 (‘severe dysfunction', n = 212). Risks of major cardiovascular events, death and hypoglycaemia and interactions with treatment were assessed using Cox proportional hazards analysis. Results Relative to normal function, both mild and severe cognitive dysfunction significantly increased the multiple-adjusted risks of major cardiovascular events (HR 1.27, 95% CI 1.11-1.46 and 1.42, 95% CI 1.01-1.99; both p < 0.05), cardiovascular death (1.41, 95% CI 1.16-1.71 and 1.56, 95% CI 0.99-2.46; both p ≤ 0.05) and all-cause death (1.33, 95% CI 1.16-1.54 and 1.50, 95% CI 1.06-2.12; both p < 0.03). Severe, but not mild, cognitive dysfunction increased the risk of severe hypoglycaemia (HR 2.10, 95% CI 1.14-3.87; p = 0.018). There was no evidence of heterogeneity of treatment effects on cardiovascular outcomes in subgroups defined by cognitive function at baseline. Conclusions/interpretation Cognitive dysfunction is an independent predictor of clinical outcomes in patients with type 2 diabetes, but does not modify the effects of BP lowering or glucose control on the risks of major cardiovascular events. Trial registration: ClinicalTrials.gov NCT00145925 Funding: Supported by grants from Servier and from the National Health and Medical Research Council of Australia.
Effects of a fixed combination of perindopril and indapamide on macrovascular and microvascular outcomes in patients with type 2 diabetes mellitus (the ADVANCE trial): a randomised controlled trial
Blood pressure is an important determinant of the risks of macrovascular and microvascular complications of type 2 diabetes, and guidelines recommend intensive lowering of blood pressure for diabetic patients with hypertension. We assessed the effects of the routine administration of an angiotensin converting enzyme (ACE) inhibitor-diuretic combination on serious vascular events in patients with diabetes, irrespective of initial blood pressure levels or the use of other blood pressure lowering drugs. The trial was done by 215 collaborating centres in 20 countries. After a 6-week active run-in period, 11 140 patients with type 2 diabetes were randomised to treatment with a fixed combination of perindopril and indapamide or matching placebo, in addition to current therapy. The primary endpoints were composites of major macrovascular and microvascular events, defined as death from cardiovascular disease, non-fatal stroke or non-fatal myocardial infarction, and new or worsening renal or diabetic eye disease, and analysis was by intention-to-treat. The macrovascular and microvascular composites were analysed jointly and separately. This trial is registered with ClinicalTrials.gov, number NCT00145925. After a mean of 4·3 years of follow-up, 73% of those assigned active treatment and 74% of those assigned control remained on randomised treatment. Compared with patients assigned placebo, those assigned active therapy had a mean reduction in systolic blood pressure of 5·6 mm Hg and diastolic blood pressure of 2·2 mm Hg. The relative risk of a major macrovascular or microvascular event was reduced by 9% (861 [15·5%] active vs 938 [16·8%] placebo; hazard ratio 0·91, 95% CI 0·83–1·00, p=0·04). The separate reductions in macrovascular and microvascular events were similar but were not independently significant (macrovascular 0·92; 0·81–1·04, p=0·16; microvascular 0·91; 0·80–1·04, p=0·16). The relative risk of death from cardiovascular disease was reduced by 18% (211 [3·8%] active vs 257 [4·6%] placebo; 0·82, 0·68–0·98, p=0·03) and death from any cause was reduced by 14% (408 [7·3%] active vs 471 [8·5%] placebo; 0·86, 0·75–0·98, p=0·03). There was no evidence that the effects of the study treatment differed by initial blood pressure level or concomitant use of other treatments at baseline. Routine administration of a fixed combination of perindopril and indapamide to patients with type 2 diabetes was well tolerated and reduced the risks of major vascular events, including death. Although the confidence limits were wide, the results suggest that over 5 years, one death due to any cause would be averted among every 79 patients assigned active therapy.
The Framingham and UK Prospective Diabetes Study (UKPDS) risk equations do not reliably estimate the probability of cardiovascular events in a large ethnically diverse sample of patients with diabetes: the Action in Diabetes and Vascular Disease: Preterax and Diamicron-MR Controlled Evaluation (ADVANCE) Study
Aims/hypothesis Available multivariable equations for cardiovascular risk assessment in people with diabetes have been derived either from the general population or from populations with diabetes. Their utility and comparative performance in a contemporary group of patients with type 2 diabetes are not well established. The aim of this study was to evaluate the performance of the Framingham and UK Prospective Diabetes Study (UKPDS) risk equations in participants who took part in the Action in Diabetes and Vascular disease: Preterax and Diamicron-MR Controlled Evaluation (ADVANCE) trial. Methods The 4-year risks of cardiovascular disease (CVD) and its constituents were estimated using two published Framingham and the UKPDS risk equations in 7,502 individuals with type 2 diabetes without prior known CVD at their enrolment in the trial. Results The risk of major CVD was overestimated by 170% (95% CI 146–195%) and 202% (176–231%) using the two Framingham equations. The risk of major coronary heart disease was overestimated by 198% (162–238%) with the UKPDS, and by 146% (117–179%) and 289% (243–341%) with the two different Framingham equations, respectively. The risks of stroke events were also overestimated with the UKPDS and one of the Framingham equations. The ability of these equations to rank risk among ADVANCE participants was modest, with c -statistics ranging from 0.57 to 0.71. Results stratified by sex, treatment allocation and ethnicity were broadly similar. Conclusions/interpretation Application of the Framingham and UKPDS risk equations to a contemporary treated group of patients with established type 2 diabetes is likely to substantially overestimate cardiovascular risk.
An alarmingly high prevalence of diabetic nephropathy in Asian type 2 diabetic patients: the MicroAlbuminuria Prevalence (MAP) Study
Microalbuminuria represents the earliest clinical evidence of diabetic nephropathy and is a marker of increased cardiovascular morbidity and mortality. Its early detection allows the implementation of individualised and aggressive intervention programmes to reduce cardiovascular risk factors. There is limited information on the prevalence of microalbuminuria among hypertensive type 2 diabetic patients in Asia. This cross-sectional epidemiological study aimed to assess the prevalence of microalbuminuria and macroalbuminuria among consecutively screened hypertensive type 2 diabetic adult patients in 103 centres in 10 Asian countries or regions. Predictive factors for microalbuminuria and macroalbuminuria were characterised using a stepwise logistic regression model. A total of 6,801 patients were enrolled and 5,549 patients constituted the per-protocol population (patients with bacteriuria and haematuria were excluded). The prevalence of microalbuminuria was 39.8% (39.2-40.5; 95% CI) and the prevalence of macroalbuminuria was 18.8% (18.2-19.3; 95% CI). Only 11.6% of the patients had systolic and diastolic blood pressure below the 130/80 mm Hg target. In the multivariate analyses, the predictive factors for the presence of microalbuminuria were age, BMI, systolic blood pressure and ethnic origin. The highlighted predictive factors for the presence of macroalbuminuria were age, sex, ethnic origin, BMI, duration of diabetes, presence of diabetic complications, intake of diuretics, intake of calcium channel blockers, diastolic and systolic blood pressure. The high prevalence (58.6%) of micro or macroalbuminuria observed in these patients is alarming and indicates an impending pandemic of diabetic cardiovascular and renal diseases in Asia with its potential economic consequences.