Biomedical subjects

X F Duan

Publications and source records attributed to X F Duan.

6 recordsLinked to original sources

PubMed2006

Synthesis and characterizations of amorphous carbon nanotubes by pyrolysis of ferrocene confined within AAM templates.

Amorphous carbon nanotubes (a-CNTs) are synthesized by pyrolysis of ferrocene confined in the nanopores of the anodic alumina membrane (AAM) and characterized by field emission scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM), electron energy-loss spectroscopy (EELS), and Raman spectroscopy. It is shown that the a-CNT has an ultrathin amorphous wall (approximately 3 nm) and a relatively large diameter (approximately 50 nm), and is capsulated with iron oxide nanoparticles. It is found that the growth of the a-CNTs is governed mainly by the template limitation effect. Electrical transport measurements on individual a-CNTs demonstrate that the a-CNT may be connected with electrodes via either ohmic or Schottky contacts, and the resisitivity of the a-CNTs was measured to be 4.5 x 10(-3) Omega cm.

Journal Article↗

PubMed2001

Nanostructure. Epitaxial diamond polytypes on silicon.

Carbon is unique in the variety of configurations it can adopt with itself and other elements. Here we show how ion beams can be used to nanostructure various diamond polytypes, epitaxially aligning them to a silicon substrate. The ready controllability of ion beams, which are already used to manufacture submicrometre-scale devices, means that our findings should enable new carbon and non-carbon materials to be nanostructured for a host of applications.

Journal Article↗

PubMed2001

[Effects of 8 years community intervention on risk factors of cardiovascular diseases in Fangshan Beijing].

OBJECTIVE: To study the changes of risk factors of cardiovascular disease in the rural community population after intervention. METHODS: The Beijing Fangshan cardiovascular prevention program was a community-based comprehensive intervention study which was launched from 1991 and ended in 2000 in five communities including three as intervention communities (IC) and two as control communities (CC) in Fangshan, Beijing suburb. The intervention measures were focused on health education and hypertension control. The changes of risk factors of cardiovascular disease in IC and CC were analyzed using random sample in the year 1991, 1995 and 1999, respectively. The risk factors include systolic and diastolic blood pressure (SBP and DBP), body mass index(BMI), serum total cholesterol(TC), triglyceride(TG), high-density lipoprotein cholesterol(HDL), smoking, and drinking. RESULTS: From the year 1991 to 1999, the risk factors of cardiovascular disease such as SBP, DBP, smoking rate and drinking rate were reduced in the population of IC. For male in IC, the decline of SBP, DBP, smoking rate, and drinking rate were 1.6 mmHg, 1.1 mmHg, 14.5% (P < 0.01) and 3.7%, respectively. For female of IC, SBP and DBP declined 4.8 mmHg (P < 0.01) and 3.2 mmHg (P < 0.01), respectively. SBP, DBP and smoking rate in the population of CC had a little reduction while BMI, TC and TG increased in both IC and CC. During the period of 1991 to 1999, most cardiovascular risk factors in the population of IC had net reduction compared to that of CC. CONCLUSIONS: Except for BMI and lipids, rural community intervention, as focused on health education and hypertension control, has resulted in the reduction of most risk factors of cardiovascular disease.

Adult↗

PubMed2001

[The effect of Beijing Fangshan Cardiovascular Prevention Program on the incidence and mortality of stroke].

OBJECTIVE: To explore potential effective measures for lowering incidence and mortality of stroke in rural community population of China. METHODS: Beijing Fangshan Cardiovascular Prevention Program (BFCP), under whole population and high risk individuals strategies with measures of health education and hypertension control, were launched in 1991 in five communities including intervention communities (IC), about 66,000 residents, and control communities (CC), about 54,000 residents, in Fangshan, Beijing suburb. RESULT: Incidences of stroke averaged 235.23 per 100,000 and 289.22 per 100,000, for IC and CC respectively, with a statistically significant difference, and mortalities of stroke averaged 80.63 per 100,000 and 98.01 per 100,000, for IC and CC respectively, with a statistically significant difference, during years of 1992 to 1999. The net change of stroke incidence was 126.13 per 100,000 in IC versus CC, with a statistically significant difference. Incidences of stroke increased by 11.63% and 75.27%, for IC and CC respectively, while mortalities of stroke decreased by 46.80% and 22.82%, respectively, for IC and CC from years of 1992 to 1999. CONCLUSION: BFCP has yielded obvious effect on controlling incidence and mortality of stroke in rural community population, but the trend of stroke incidence increasing was still not restrained radically.

Cardiovascular Diseases↗

PubMed2000

High-resolution transmission electron microscopy investigations of a highly adhesive hydroxyapatite coating/titanium interface fabricated by ion-beam-assisted deposition.

An atomic intermixing layer, 25 nm in width, has been identified by high-resolution transmission electron microscopy (HRTEM) and energy-dispersive X-ray spectroscopy (EDS) analysis at the ceramic/metal interface of a hydroxyapatite (HA) coating/titanium implant prepared by an ion-beam-assisted deposition (IBAD) technique and post-heat-treatment process. The detailed interfacial microstructure revealed a gradient evolution of both the structure and composition of the interfacial phases from the titanium substrate to HA coatings. An enhancement of the tensile bond strength was found and was attributed to the possible chemical bonding at the ceramic/metal interface.

Biocompatible Materials↗

PubMed1998

Applications of microdiffraction related to HREM.

This paper deals with the coherent and the incoherent microdiffraction, as well as their applications, for example, determination of the nature of defects and boundaries, measurement of the strain field and identification of the symmetry, etc. The localized structure information obtained from microdiffraction has been compared with and complements that provided by HREM.

Alloys↗