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Energy-based surgical instrumentation (ESI) are surgical devices ablating or cutting tissues via the application of electrical,luminous,acoustic or other energy.High frequency electrotomes are widely used due to the low price,but they produce smoke in the process of surgery and incisions heal slowly.Ultrasonically activated scalpels' cutting performance is satisfying with easily healing incisions while its coagulating capability is poor.Laser scalpels are qualified for both cutting and coagulating in spite of the need of novel technology to overcome the characteristic that tissues absorb laser wavelength selectively.
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Based on the teaching practice,this paper discussed nine topics in fluid dynamics:scientific research methods,theoretical foundation of hemodynamics and hemorheology,physical meaning of Bernoulli's equation,physical meaning of Newton viscosity law,Poiseuille principle on flow blood,mathematical description of volume flow,concept of velocity gradient,physical meaning of Reynolds number,and flow resistance.By combining preparing lessons and teaching practice,this paper comments on these nine topics and point out several inaccurate descriptions in some textbook.As a reference,it could benefit for teachers and students.
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Objective To compare the histological effects of 1.44-?m and 1.06-?m pulse Nd:YAG laser radiation on stomach wall tissues in dogs. Methods Five beagle dogs were enrolled in this study to received 1.44-?m(experiment group) and 1.06-?m(self-control group) pulse Nd:YAG laser radiation at the posterior wall of the stomach.Totally 19 dosage of radiation was used including a 0-mJ radiation.The dosage of every single pulse was 200,500,or 800 mJ,and the amount of the pulses was 1,5,10,20,40 or 80.The experiment was repeated for 5 times.Afterwards,the injured tissues was obtained and observed under a light microscope and the photomicrograph was taken at the meantime.Results In experimental groups,the widest and photoevaporated zone and coagulation zone were(1863.8?225.0) ?m and(885.1?82.9) ?m,and the deepest photoevaporated zone and coagulation zone were(1787.4?93.7) ?m and(1327.8?86.3) ?m,respectively;which were significantly higher than those in the control [widest and photoevaporated zone and coagulation zone:(576.8?30.8) ?m and(1275.8?140.1) ?m,t=12.672,P=0.000 and t=-5.366,P=0.001;deepest photoevaporated zone and coagulation zone:(105.0?16.3) ?m and(994.8?130.0) ?m,t=39.539,P=0.000 and t=4.773,P=0.002;respectively].Conclusions 1.44-?m Nd:YAG laser is suitable for vaporization and coagulation in stomach surgery.It shows higher ability in vaporization but lower ability of coagulation than 1.06-?m pulse Nd:YAG laser radiation,which,however does not affect the outcomes of wound cleansing and hemostasis.