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Biomedical subjects

Y Y Cheng

Publications and source records attributed to Y Y Cheng.

36 records · Page 2Linked to original sources

Acrylic resin reinforced with chopped high performance polyethylene fiber--properties and denture construction.

A newly developed incremental mixing technique has been used to incorporate over 30 vol % chopped high performance polyethylene fiber into acrylic denture base resin. The reinforcement produced a substantial improvement in several clinically important properties, namely: 1) stiffness and impact strength were higher; 2) the mechanical properties were insensitive to notches that mimic anatomical features; and 3) samples damaged during bending and impact did not break up into separate fragments. Reinforced complete maxillary and mandibular dentures of good esthetic appearance were successfully manufactured and polished with conventional laboratory techniques.

Acrylic Resins↗

[Effect of Salvia miltiorrhiza on the cardial ischemia in rats induced by ligation].

I.p. injection (5 g crude drug/kg) of water extract of Salvia miltiorrhiza to S.D. rats can prevent the acute cardial ischemia induced by the ligation of the coronary artery. The elevation of S-T segment in the electrocardiogram caused by the ischemia was greatly reduced in animals treated with Salvia miltiorrhiza compared with control group. The ischemia area in the left ventricle was significantly reduced and survival rate of the rats increased.

Animals↗

[Prevention and treatment of isoproterenol induced ventricular fibrillation in rats by aqueous extract of Salvia miltiorrhiza].

Acute fatal ventricular fibrillation (VF) in male Sprague-Dawley rats was induced by subcutaneous injection of isoproterenol (1 mg or 5 mg/kg body weight) to two groups of rats of different body weights (525 +/- 21 g or 387 +/- 11 g) respectively. VF occurred in all control rats resulting in 96% death with only 4% spontaneously reverted and survived. Pretreatment of animals, with or without pentobarbital anaesthesia, with an aqueous extract of Salvia miltiorrhiza (SM-H, i.p., 5 g herb/kg body weight) significantly reduced J-point displacement and VF induced by isoproterenol. Survival rate was significantly raised compared with the control (P less than 0.05). Immediate intravenous injection of SM-H (5 g herb/kg body weight) to poisoned rats which developed VF caused 71% of them to recover temporarily their sinus rhythm and significantly prolonged their survival time (P less than 0.05).

Animals↗

The effect of selenium-fortified table salt in the prevention of Keshan disease on a population of 1.05 million.

The preventive effect of selenium (Se)-fortified table salt against Keshan disease (an endemic myocardiopathy) was tested on 1.05 million people with another 0.6 million people as the control. The average annual incidence of acute and subacute types of the disease significantly decreased from 25.23 to 2.7 per 100,000 in the Se-supplemented population, while the corresponding rate in the control decreased from 19.76 to 7.36 per 100,000. Furthermore, the detection rate of new cases of a latent type of Keshan disease in the Se-supplemented group (0.18%) was significantly lower than that in the control group (1.07).

Cardiomyopathies↗

[Protective action of Salvia miltiorrhiza aqueous extract on chemically induced acute myocardial ischemia in rats].

Aqueous extract of Salvia miltiorrhiza (SM-H) can protect the acute myocardial ischemia and arrhythmia of Sprague-Dawley rats induced by isoproterenol (ISO) or BaCl2 with the following results: (1) intraperitoneal injection (i.p.) of SM-H for 3 to 5 days or intravenously (i.v.) just once significantly reduced the death rate of the animals, (2) i.v. SM-H pretreatment significantly increased the lethal dose of BaCl2 infusion, (3) i.p. SM-H significantly decreased premature ventricular contraction, ventricular fibrillation, bradycardia and mortality rate induced by bolus i.v. of BaCl2, and (4) i.p. SM-H also significantly reduced ECG J-point displacement of rats induced by ISO.

Animals↗

Denture base reinforcement using woven polyethylene fiber.

Reinforcement of acrylic denture base resin with high-performance polyethylene fiber in woven form produced a substantial improvement of stiffness and impact strength, as well as reducing the sensitivity of the material to notches that mimic anatomic features. The mechanical properties of the new systems were not affected by water immersion. Reinforced complete maxillary and mandibular dentures having good appearance and satisfactory fiber/resin integration were achieved using conventional laboratory techniques. These prostheses are undergoing clinical trials with encouraging results.

Analysis of Variance↗