Biomedical subjects

Yan Deng

Publications and source records attributed to Yan Deng.

22 records · Page 2Linked to original sources

PubMed2003

Cardiac conductive system excitation maps using intracardiac tissue Doppler imaging.

OBJECTIVE: To precisely visualize cardiac anatomic structures and simultaneously depict electro-mechanical events for the purpose of precise underblood intervention. METHODS: Intracardiac high-resolution tissue Doppler imaging was used to map real time myocardial contractions in response to electrical activation within the anatomic structure of the cardiac conductive system using a canine open-chest model. RESULTS: The detailed inner anatomic structure of the cardiac conductive system at different sites (i.e., sino-atrial, atrial wall, atrial-ventricular node and ventricular wall) with the inside onset and propagation of myocardial velocity and acceleration induced by electrical activation was clearly visualized and quantitatively evaluated. CONCLUSION: The simultaneous single modality visualization of the anatomy, function and electrical events of the cardiac conductive system will foster target pacing and precision ablation.

Animals↗

PubMed2002

Characterization of damage modes in dental ceramic bilayer structures.

Results of contact tests using spherical indenters on flat ceramic coating layers bonded to compliant substrates are reported for selected dental ceramics. Critical loads to produce various damage modes, cone cracking, and quasiplasticity at the top surfaces and radial cracking at the lower (inner) surfaces are measured as a function of ceramic-layer thickness. It is proposed that these damage modes, especially radial cracking, are directly relevant to the failure of all-ceramic dental crowns. The critical load data are analyzed with the use of explicit fracture-mechanics relations, expressible in terms of routinely measurable material parameters (elastic modulus, strength, toughness, hardness) and essential geometrical variables (layer thickness, contact radius). The utility of such analyses in the design of ceramic/substrate bilayer systems for optimal resistance to lifetime-threatening damage is discussed.

Ceramics↗

PubMed2002

The prevalence of malocclusion in China--an investigation of 25,392 children.

OBJECTIVE: To investigate the prevalence of malocclusion in China. METHODS: Based on individual normal occlusion and Angle's classification of malocclusion, standard investigation form was made. 25,392 children of different dental ages were evaluated by orthodontic professionals. RESULTS: The prevalence of malocclusion among Chinese children was 67.82%. The prevalence of malocclusion among children with different dental age and the proportion of the different types of malocclusions were revealed. CONCLUSION: The prevalence of malocclusion among Chinese children had increased from 40% to 67% over the last 40 years.

Child↗

PubMed2002

[Effect of Tribulus terrestris L decoction of different concentrations on tyrosinase activity and the proliferation of melanocytes].

OBJECTIVE: To study the effects of the decoction of Tribulus terrestris L on tyrosinase activity and melanogenesis. METHODS: MTT was employed to study the proliferation of human melanocytes cultured in vitro, and tyrosinase activity was estimated by measuring the rate of oxidation of DL-dopa, after the cells were treated with different concentrations of decoction of Tribulus terrestris L. RESULTS: The treatment with the decoction increased the amount of melanin at higher concentrations but act to the reverse effect at lower concentrations, with the best concentrations for promoting and inhibiting the cell growth being 1.5 mg/ml (P<0.05) and 0.5 mg/ml (P<0.05) respectively. At high concentrations the decoction enhanced the tyrosinase activity that was inhibited at low concentrations. The best concentrations for enhancing and inhibiting tyrosinase activity were 100 mg/ml (P<0.05) and 10 mg/ml (P<0.05) respectively. CONCLUSION: Tribulus terrestris L decoction exercises a two-way regulation on the activity of tyrosinase and the proliferation of melanocytes.

Cell Division↗