14 research outputs found
Effect of Potential Energy Distribution on the Melting of Clusters
We find that the potential energy distribution of atoms in clusters can consistently explain many important phenomena related to the phase changes of clusters, such as the nonmonotonic variation of melting temperature with size, the dependence of melting, boiling, and sublimation temperatures on the interatomic potentials, the existence of a surface-melted phase, and the absence of a premelting peak in heat capacity curves. We also find a new type of premelting mechanism in double icosahedral Pd19 clusters, where one of the two internal atoms escapes to the surface at the premelting temperature.Peer reviewe
Breathing silicon anodes for durable high-power operations
Silicon anode materials have been developed to achieve high capacity lithium ion batteries for operating smart phones and driving electric vehicles for longer time. Serious volume expansion induced by lithiation, which is the main drawback of silicon, has been challenged by multi-faceted approaches. Mechanically rigid and stiff polymers (e.g. alginate and carboxymethyl cellulose) were considered as the good choices of binders for silicon because they grab silicon particles in a tight and rigid way so that pulverization and then break-away of the active mass from electric pathways are suppressed. Contrary to the public wisdom, in this work, we demonstrate that electrochemical performances are secured better by letting silicon electrodes breathe in and out lithium ions with volume change rather than by fixing their dimensions. The breathing electrodes were achieved by using a polysaccharide (pullulan), the conformation of which is modulated from chair to boat during elongation. The conformational transition of pullulan was originated from its a glycosidic linkages while the conventional rigid polysaccharide binders have beta linkagesopen1
Hemostasis pad combined with compression device after transradial coronary procedures: A randomized controlled trial.
Arterial access and hemostasis are important processes during percutaneous coronary procedures. In this study, we tested if the use of chitosan-based pads on top of compression devices could improve hemostasis efficacy compared with compression devices alone after transradial coronary angiography or interventions.This study was a single-center open-label randomized controlled trial. Patients who underwent coronary angiography or intervention with the transradial approach were randomly assigned to the study (compression device and a chitosan-based pad) or control (compression devices alone) group in a 2:1 fashion. The primary endpoint was time to hemostasis, categorized into ≤5, 6-10, 11-20, and >20 minutes.Between April and July 2016, 95 patients were enrolled (59 were assigned to the study arm and 36 to the control arm). Time to hemostasis, the primary endpoint, was significantly lower in the study group than in the control group (p<0.001). Both groups showed low rates of vascular complications.This study suggests that the use of a hemostasis pad in combination with rotatory compression devices is a safe and effective hemostasis strategy after radial artery access.ClinicalTrials.gov NCT02954029
Baseline characteristics of study patients.
<p>Baseline characteristics of study patients.</p
Baseline characteristics of study patients.
<p>Baseline characteristics of study patients.</p
Study devices.
<p>(A) Both rotatory compression device and hemostasis pad were used for the patients in the study group. (B) After placing the hemostasis pad over the puncture site, the rotatory compression device was applied.</p
The primary endpoint, time to hemostasis of the study and control groups.
<p>The primary endpoint, time to hemostasis of the study and control groups.</p
Subjective discomfort assessed by visual analogue scale.
<p>Subjective discomfort assessed by visual analogue scale.</p
Increased epicardial adipose tissue thickness is a predictor of new-onset diabetes mellitus in patients with coronary artery disease treated with high-intensity statins
Abstract Background Statins are widely used for lipid lowering in patients with coronary artery disease (CAD), but increasing evidence indicates an association between statin use and new-onset of diabetes mellitus (NODM). Epicardial adipose tissue (EAT) refers to the visceral fat surrounding the heart, which is associated with metabolic diseases. We sought to determine the association between EAT thickness and NODM in CAD patients treated with high-intensity statins. Methods We conducted a retrospective medical record review of CAD patients treated with high-intensity statins for at least 6 months after percutaneous coronary intervention performed between January 2009 and June 2013 at Seoul National University Bundang Hospital. EAT thickness was measured by echocardiography using standardized methods. Results A total of 321 patients were enrolled, who received high-intensity statins for a mean of 952 days; atorvastatin 40 mg in 204 patients (63.6%), atorvastatin 80 mg in 57 patients (17.8%), and rosuvastatin 20 mg in 60 patients (18.7%). During the follow-up period of 3.9 ± 1.7 years, NODM occurred in 40 patients (12.5%). On Cox proportional-hazard regression analysis, EAT thickness at systole [for each 1 mm: hazard ratio (HR) 1.580; 95% confidence interval (CI) 1.346–1.854; P < 0.001] and prediabetes at baseline (HR 4.321; 95% CI 1.998–9.349; P < 0.001) were the only independent predictors of NODM. Using binary cutoff values derived from the receiver operating characteristic curve analysis, EAT thickness at systole larger than 5.0 mm had an HR of 3.402 (95% CI 1.751–6.611, P < 0.001), sensitivity of 52.5%, and specificity of 80.8% for predicting NODM. Also, patients with EAT thickness ≥ 5 mm and prediabetes at baseline had a 12.0-times higher risk of developing NODM compared to the risk noted in patients with EAT thickness < 5 mm and normal glucose tolerance at baseline. Conclusion Epicardial adipose tissue thickness at systole is a consistent independent predictor of NODM in patients with CAD treated with high-intensity statins. Such predictors may help physicians plan adequate surveillance for early detection of NODM