Plant leaves, insects and geckos are masters of adhesion or anti-adhesion by smartly designed refined surface structures with micro- and nano- ＇technologies＇. Understanding the basic principles in the design of the ...Plant leaves, insects and geckos are masters of adhesion or anti-adhesion by smartly designed refined surface structures with micro- and nano- ＇technologies＇. Understanding the basic principles in the design of the unique surface structures is of great importance in the manufacture or synthesis of micro- and nano- devices in MEMS or NEMS. This study is right inspired by this effort, focusing on the mechanics of wet adhesion between fibers having concave tips and a flat substrate via capillary forces. We show that the concave surface can effectively enhance the wet adhesion by reducing the effective contact angle of the fiber, firmly pinning the liquid bridge at its circumferential edge. A critical contact angle is identified below which the adhesion strength can achieve its maximum, being insensitive to the contact angle between the fiber and liquid. The analytical expression for the critical angle is derived. Then a tentative design for the profile of concave surfaces is proposed, considering the effects of chamfering size, deformation and buckling, etc. The effect of liquid volume on the wet adhesion of multiple-fiber system is also discussed.展开更多
Objectives To ob-serve the effect of different estrogen levels on the secretory function of vascular endothelial cells of female rats, and study the effect of modulation of estrogen level on the expression of vascular...Objectives To ob-serve the effect of different estrogen levels on the secretory function of vascular endothelial cells of female rats, and study the effect of modulation of estrogen level on the expression of vascular cell adhesion molecule - 1 and the concentration of estrogen receptor in vascular endothelial cells. Methods Radioim-munology was used to measure the serum concentration of endothelin and PGI2, and copper - cadmium reduction was employed to measure the serum content of nitrogen monoxide. Radioligand binding and flowcy-tometry were used to measure the expression of estrogen receptor and vascular cell adhesion molecule (VCAM - 1) of vascular endothelial cells respectively. Results 1. The serum concentration of nitric oxide and PGI2 decreased when the ovaries of female rats were removed. In ovariectomized rats, given estrogen, the concentration rose ( P < 0. 05), but the plasma concentration of endothelin was adverse to it. 2. The concentration of estrogen receptor of vascular endothelial cells decreased remarkably when the ovaries of female rats were removed. When given estrogen, it increased. 3. The percent of expressed VCAM - 1 increased significantly after interleukin - 1βoperated on the cells, but 17 -βestradiol at 3 × 10-8 - 10-6 mol/l all decreased the percent. Conclusions Estrogen level can influence the secretion of nitrogen monoxide, PGI2 and endothlin of vascular endothelial cells, and also influence the concentration of estrogen receptor of vascular endothelial cells. 17 -β Estradiol at 3 × 10-8 -10-6 M can decrease the elevation of VCAM - 1 of vascular endothelial cells induced by interleukin - 1β.展开更多
目的:体外观察左氧氟沙星(LFX)涂敷导管对铜绿假单胞菌黏附、定植能力的影响,探讨LFX涂敷导管在铜绿假单胞菌导管相关感染中的应用价值。方法:制备LFX涂敷导管,测定LFX涂敷导管的体外药物累积释放度。实验分为LFX涂敷导管组和聚氯乙烯(P...目的:体外观察左氧氟沙星(LFX)涂敷导管对铜绿假单胞菌黏附、定植能力的影响,探讨LFX涂敷导管在铜绿假单胞菌导管相关感染中的应用价值。方法:制备LFX涂敷导管,测定LFX涂敷导管的体外药物累积释放度。实验分为LFX涂敷导管组和聚氯乙烯(PVC)导管组,2组导管分别浸没于5 mL 50%LB培养液中(含铜绿假单胞菌108 CFU/mL),37℃孵育6h、12h、24h、48h,在各时间点,分别于导管表面和导管培养液进行细菌计数。结果:LFX涂敷导管能够在2h内实现药物的快速释放,2h后LFX涂敷导管药物释放很少,甚至没有释放。LFX对实验菌PAO1的最小抑菌浓度(MIC)和最小杀菌浓度(MBC)分别为0.5mg/L、1.0mg/L;6h、12h、24h孵育时间点,LFX1∶3、LFX1∶6、LFX1∶9涂敷导管表面定植、黏附细菌培养均为阴性;且LFX1∶3、LFX1∶6、LFX1∶9涂敷导管在不同孵育时间点培养液的细菌数较PVC导管培养液的细菌数明显减少(P<0.05)。结论:LFX涂敷导管能有效抑制铜绿假单胞菌黏附、定植,提示LFX涂敷导管可作为预防铜绿假单胞菌导管相关感染的有效策略。展开更多
基金supported by the National Natural Science Foundation of China through Grant Nos 10628205,10732050 and10872115National Basic Research Program of China through Grant No 2007CB936803,and SRF-SEM for ROCS
文摘Plant leaves, insects and geckos are masters of adhesion or anti-adhesion by smartly designed refined surface structures with micro- and nano- ＇technologies＇. Understanding the basic principles in the design of the unique surface structures is of great importance in the manufacture or synthesis of micro- and nano- devices in MEMS or NEMS. This study is right inspired by this effort, focusing on the mechanics of wet adhesion between fibers having concave tips and a flat substrate via capillary forces. We show that the concave surface can effectively enhance the wet adhesion by reducing the effective contact angle of the fiber, firmly pinning the liquid bridge at its circumferential edge. A critical contact angle is identified below which the adhesion strength can achieve its maximum, being insensitive to the contact angle between the fiber and liquid. The analytical expression for the critical angle is derived. Then a tentative design for the profile of concave surfaces is proposed, considering the effects of chamfering size, deformation and buckling, etc. The effect of liquid volume on the wet adhesion of multiple-fiber system is also discussed.
文摘Objectives To ob-serve the effect of different estrogen levels on the secretory function of vascular endothelial cells of female rats, and study the effect of modulation of estrogen level on the expression of vascular cell adhesion molecule - 1 and the concentration of estrogen receptor in vascular endothelial cells. Methods Radioim-munology was used to measure the serum concentration of endothelin and PGI2, and copper - cadmium reduction was employed to measure the serum content of nitrogen monoxide. Radioligand binding and flowcy-tometry were used to measure the expression of estrogen receptor and vascular cell adhesion molecule (VCAM - 1) of vascular endothelial cells respectively. Results 1. The serum concentration of nitric oxide and PGI2 decreased when the ovaries of female rats were removed. In ovariectomized rats, given estrogen, the concentration rose ( P < 0. 05), but the plasma concentration of endothelin was adverse to it. 2. The concentration of estrogen receptor of vascular endothelial cells decreased remarkably when the ovaries of female rats were removed. When given estrogen, it increased. 3. The percent of expressed VCAM - 1 increased significantly after interleukin - 1βoperated on the cells, but 17 -βestradiol at 3 × 10-8 - 10-6 mol/l all decreased the percent. Conclusions Estrogen level can influence the secretion of nitrogen monoxide, PGI2 and endothlin of vascular endothelial cells, and also influence the concentration of estrogen receptor of vascular endothelial cells. 17 -β Estradiol at 3 × 10-8 -10-6 M can decrease the elevation of VCAM - 1 of vascular endothelial cells induced by interleukin - 1β.
文摘目的:体外观察左氧氟沙星(LFX)涂敷导管对铜绿假单胞菌黏附、定植能力的影响,探讨LFX涂敷导管在铜绿假单胞菌导管相关感染中的应用价值。方法:制备LFX涂敷导管,测定LFX涂敷导管的体外药物累积释放度。实验分为LFX涂敷导管组和聚氯乙烯(PVC)导管组,2组导管分别浸没于5 mL 50%LB培养液中(含铜绿假单胞菌108 CFU/mL),37℃孵育6h、12h、24h、48h,在各时间点,分别于导管表面和导管培养液进行细菌计数。结果:LFX涂敷导管能够在2h内实现药物的快速释放,2h后LFX涂敷导管药物释放很少,甚至没有释放。LFX对实验菌PAO1的最小抑菌浓度(MIC)和最小杀菌浓度(MBC)分别为0.5mg/L、1.0mg/L;6h、12h、24h孵育时间点,LFX1∶3、LFX1∶6、LFX1∶9涂敷导管表面定植、黏附细菌培养均为阴性;且LFX1∶3、LFX1∶6、LFX1∶9涂敷导管在不同孵育时间点培养液的细菌数较PVC导管培养液的细菌数明显减少(P<0.05)。结论:LFX涂敷导管能有效抑制铜绿假单胞菌黏附、定植,提示LFX涂敷导管可作为预防铜绿假单胞菌导管相关感染的有效策略。
文摘目的观察西洛他唑联合替米沙坦对早期2型糖尿病肾病(diabetic nephropathy,DN)血清单核细胞趋化蛋白1(MCP-1)和可溶性细胞间黏附分子1(s ICAM-1)的影响。方法将我院收治的早期2型DN 60例随机分为西洛他唑联合替米沙坦组和替米沙坦组两组各30例,在常规治疗基础上西洛他唑联合替米沙坦组予西洛他唑和替米沙坦治疗,替米沙坦组仅予替米沙坦治疗,观察比较两组治疗前及治疗4周后24 h尿微量白蛋白、血压及血清MCP-1、s Ic AM-1、丙氨酸转氨酶、肌酐、糖化血红蛋白水平。结果治疗4周后,两组24 h尿微量白蛋白及血清MCP-1、s Ic AM-1均较治疗前明显下降,差异有统计学意义(P<0.05);西洛他唑联合替米沙坦组24 h尿微量白蛋白及血清MCP-1、s Ic AM-1均明显低于替米沙坦组,差异亦有统计学意义(P<0.05)。结论西洛他唑联合替米沙坦可减少早期2型DN患者尿白蛋白排出,保护肾脏,延缓疾病进展,且临床应用相对安全。
