Factors Influencing Time to First Medical Contact in Patients with Acute ST-Segment Elevation Myocardial Infarction: A Retrospective Analysis.

BACKGROUND Exploring the factors that impact the time from symptom onset to first medical contact (S2FMC) is crucial for improving outcomes in elderly patients diagnosed with acute ST-segment elevation myocardial infarction (STEMI). This study conducted a retrospective analysis on 282 patients who underwent emergency percutaneous coronary intervention (PCI) or percutaneous transluminal coronary angioplasty (PTCA) in Guangzhou City District to identify significant factors affecting S2FMC. MATERIAL AND METHODS A retrospective analysis was conducted on 282 patients with STEMI who underwent emergency percutaneous coronary intervention (PCI). Descriptive statistics, univariate and multivariate Cox regression analyses were used to identify significant factors affecting S2FMC. Additionally, interactions between risk factors were examined using multivariate logistic regression and the structural equation model (SEM). RESULTS Age (HR=0.984, 95% CI: 0.975-0.993), nature of chest pain (HR=2.561, 95% CI: 1.900-3.458), admission mode (HR=1.805, 95% CI: 1.358-2.400), and vascular characteristics (HR=1.246, 95% CI: 1.069-1.451) were independent influencing factors for S2FMC. Persistent chest tightness/pain, EMS admission, and vascular characteristics (RCADL or LCADL) played a protective role in S2FMC. Among the influencing factors, vascular characteristics (OR=1.072, 95% CI: 1.008-1.141) had an independent effect on the nature of chest pain. Meanwhile, the nature of chest pain (OR=1.148, 95% CI: 1.015-1.298) was an independent influencing factor in the admission mode. CONCLUSIONS Patients with persistent chest tightness/pain, EMS admission, and vascular characteristics (RCADL or LCADL) experienced shorter S2FMC and higher compliance rate (S2FMC ≤180 min). At the same time, age and other vascular features played an inverse role. This study proposes enhancing follow-up and monitoring measures, and shows the consequences of intermittent chest pain should not be disregarded.

Nanostructures for thermoelectric applications: synthesis, growth mechanism, and property studies.

Both heterostructures and hollow nanostructures have been predicted as candidates with excellent thermoelectric performance. In this Research News areticle, recent advances with regard to synthetic strategies, growth mechanisms, and thermoelectric properties of one-dimensional heterostructures (segmented and core/shell) and tubular nanostructures are reported. The thermoelectric property studies of Te/Bi core/shell heterostructured nanowires and Bi(2)Te(3) nanotubes indicate that the Seebeck coefficient and thermal conductivity of these materials can be optimized to improve their thermoelectric performance. In addition, the current issues and future research directions for promising thermoelectric nanostructures will be discussed on the basis of these experimental results.

Wet chemical synthesis and thermoelectric properties of V-VI one- and two-dimensional nanostructures.

Recent advances in both theoretical and experimental studies on optimizing thermoelectric performance have proved to greatly benefit from nanostructure engineering. As a class of materials with the best thermoelectric properties near room temperature, V-VI alloy nanostructures, especially Bi(2)Te(3) and its alloy with Sb, Se and so on, have attracted a broad interest. This perspective gives an overview of the progress in the wet chemical synthesis and property study of V-VI related one- and two-dimensional nanostructures. First, we discuss the preparation of one-dimensional nanowires/tubes, axial and radial modulated heterostructures, and two-dimensional platelet-like structures through various chemical routes. Then, we attempt to give a general outlook on the thermoelectric properties of V-VI single nanowires, and nanostructured films or bulk nanocomposites made of these chemically synthesized nanostructures. On the basis of the research in the synthetic methods and thermoelectric properties, the challenging issues and future research directions are briefly discussed. By no means is this a comprehensive coverage of V-VI related nanostructures, but a selection of those studies that could benefit the advance of thermoelectric properties of this material system in the near future.

Large scale highly crystalline Bi2Te3 nanotubes through solution phase nanoscale Kirkendall effect fabrication.

We have successfully developed an ethylene glycol mediated solution phase method for synthesizing highly crystalline Bi(2)Te(3) nanotubes using Te nanowires as the in situ templates; our work demonstrates the generic feature of a solution phase mediated Kirkendall effect for the synthesis of not only hollow nanoparticles but also highly crystalline tubular structures.