Polyurethane (PU) was prepared from palm kernel oil-based monoester polyol (PKO-p) via prepolymerization method at NCO/OH ratio of 200/100, 150/100, 100/100, and 75/100 at ambient temperature under nitrogen gas atmosp...Polyurethane (PU) was prepared from palm kernel oil-based monoester polyol (PKO-p) via prepolymerization method at NCO/OH ratio of 200/100, 150/100, 100/100, and 75/100 at ambient temperature under nitrogen gas atmosphere. The structure of the synthesized prepolymerized PKO-p PU was determined using FTIR and 13C NMR. The disapperance of NCO peak in the FTIR spectrum at 2270 cm–1 - 2250 cm–1 cm showed that MDI has completely reacted to form PU. The appearance of C=O peak at 1700 cm–1 indicated that hydrogen bonding was formed between the soft segmented chain of the PKO-p and the hard segmented MDI. Hence, urethane bond was the main polymeric chain in the PU.展开更多
Dihydrotestosterone (DHT) is implicated in the development of benign prostate hyperplasia (BPH). We investigated if Uromedic? pumpkin (variety of Cucurbita pepo L. convar. citrullinina GREB. var. styriaca GREB) seed s...Dihydrotestosterone (DHT) is implicated in the development of benign prostate hyperplasia (BPH). We investigated if Uromedic? pumpkin (variety of Cucurbita pepo L. convar. citrullinina GREB. var. styriaca GREB) seed soft extract (active ingredients of GRANUFINK? Prosta forte 500 mg), seed oil and isolated Δ7-sterols could inhibit the conversion of [1,2,6,7-3H(N)]-testosterone to DHT by 5α-reductases. Also, we tested competition with [3H]-DHT for binding to the androgen receptor (AR). Pumpkin seed oil and pumpkin seed soft extract were identified as moderately active inhibitors of 5α-R1 and 5α-R2, with almost similar inhibitory capacities (IC50 5 mg/ml for 5α-R1 and about IC50 = 6 mg/ml for 5α-R2). The isolated Δ7-sterols were more active inhibitors (IC50 = 0.3 mg/ml for 5α-R1, IC50 = 1.0 mg/ml for 5α-R2). All three test compounds bound to the AR dose-dependently, with strong binding by Δ7-sterols (IC50 = 0.2 mg/ml) and weaker binding by pumpkin seed oil (IC50 = 0.4 mg/ml) and pumpkin seed soft extract (IC50 = 1.1 mg/ml). We propose that inhibition of 5α-reductases and competitive binding to the AR are mechanisms of action, by which the Uromedic? pumpkin seed derived test compounds, most specifically Δ7-sterols, counteract DHT and thereby exert clinically positive effects on the prostate, as well as bladder-strengthening effects.展开更多
Squeeze oil film damper are widely used in small high-speed aeroengine.But they are all made of high-hardness alloy steel. In order to improve their vibration absorption performance a new style of soft metal plated da...Squeeze oil film damper are widely used in small high-speed aeroengine.But they are all made of high-hardness alloy steel. In order to improve their vibration absorption performance a new style of soft metal plated damper has been studied. A coat of soft metal is plated on inner surface of the oil film ring, the surface will be deformed to some extent under the effect of oil film pressure. The characteristics of such dampers are calculated and analysed. Result shows that, compared with common damper, the new style damper can change oil film pressure distribution, enhance oil film damping, decrease stiffness, and reduce the force transfered to casing.展开更多
文摘Polyurethane (PU) was prepared from palm kernel oil-based monoester polyol (PKO-p) via prepolymerization method at NCO/OH ratio of 200/100, 150/100, 100/100, and 75/100 at ambient temperature under nitrogen gas atmosphere. The structure of the synthesized prepolymerized PKO-p PU was determined using FTIR and 13C NMR. The disapperance of NCO peak in the FTIR spectrum at 2270 cm–1 - 2250 cm–1 cm showed that MDI has completely reacted to form PU. The appearance of C=O peak at 1700 cm–1 indicated that hydrogen bonding was formed between the soft segmented chain of the PKO-p and the hard segmented MDI. Hence, urethane bond was the main polymeric chain in the PU.
文摘Dihydrotestosterone (DHT) is implicated in the development of benign prostate hyperplasia (BPH). We investigated if Uromedic? pumpkin (variety of Cucurbita pepo L. convar. citrullinina GREB. var. styriaca GREB) seed soft extract (active ingredients of GRANUFINK? Prosta forte 500 mg), seed oil and isolated Δ7-sterols could inhibit the conversion of [1,2,6,7-3H(N)]-testosterone to DHT by 5α-reductases. Also, we tested competition with [3H]-DHT for binding to the androgen receptor (AR). Pumpkin seed oil and pumpkin seed soft extract were identified as moderately active inhibitors of 5α-R1 and 5α-R2, with almost similar inhibitory capacities (IC50 5 mg/ml for 5α-R1 and about IC50 = 6 mg/ml for 5α-R2). The isolated Δ7-sterols were more active inhibitors (IC50 = 0.3 mg/ml for 5α-R1, IC50 = 1.0 mg/ml for 5α-R2). All three test compounds bound to the AR dose-dependently, with strong binding by Δ7-sterols (IC50 = 0.2 mg/ml) and weaker binding by pumpkin seed oil (IC50 = 0.4 mg/ml) and pumpkin seed soft extract (IC50 = 1.1 mg/ml). We propose that inhibition of 5α-reductases and competitive binding to the AR are mechanisms of action, by which the Uromedic? pumpkin seed derived test compounds, most specifically Δ7-sterols, counteract DHT and thereby exert clinically positive effects on the prostate, as well as bladder-strengthening effects.
文摘Squeeze oil film damper are widely used in small high-speed aeroengine.But they are all made of high-hardness alloy steel. In order to improve their vibration absorption performance a new style of soft metal plated damper has been studied. A coat of soft metal is plated on inner surface of the oil film ring, the surface will be deformed to some extent under the effect of oil film pressure. The characteristics of such dampers are calculated and analysed. Result shows that, compared with common damper, the new style damper can change oil film pressure distribution, enhance oil film damping, decrease stiffness, and reduce the force transfered to casing.
文摘为研究亚麻籽油磷虾油软胶囊对高血脂的缓解功效,将50只雄性大鼠随机分为5组,高脂饲料造模7 d,经口给予大鼠不同剂量的亚麻籽油磷虾油软胶囊内容物30 d。通过检测各组大鼠血清中甘油三酯(triglyceride,TG)、总胆固醇(total cholesterol,TC)、低密度脂蛋白胆固醇(low density lipoprotein cholesterol,LDL-C)和高密度脂蛋白胆固醇(high density lipoprotein cholesterol,HDL-C)指标,评价亚麻籽油磷虾油软胶囊辅助降血脂的功效。结果显示:与空白对照组比较,模型组血清中TC、TG、LDL-C均极显著升高(P<0.01),说明模型成立;与模型对照组相比,低、高剂量组大鼠TC含量显著降低(P<0.05),分别降低了13.73%和14.79%;各剂量组大鼠TG、LDL-C含量均显著降低,TG分别降低了45.87%、55.44%和64.03%,LDL-C分别降低了40.54%、26.12%和46.85%,各剂量组大鼠体重及HDL-C无显著性差异,表明亚麻籽油磷虾油软胶囊具有辅助降血脂的功效。
