| 5 | Effects of Histotripsy on Local Tumor Progression in an in vivo Orthotopic Rodent Liver Tumor Model显示文摘Objective and Impact Statement.This is the first longitudinal study investigating the effects of histotripsy on local tumor progression in an in vivo orthotopic,immunocompetent rat hepatocellular carcinoma(HCC)model.Introduction.Histotripsy is the first noninvasive,nonionizing,nonthermal,mechanical ablation technique using ultrasound to generate acoustic cavitation to liquefy the target tissue into acellular debris with millimeter accuracy.Previously,histotripsy has demonstrated in vivo ablation of noncancerous liver tissue.Methods.N1-S1 HCC tumors were generated in the livers of immunocompetent rats(n=6,control;n=15,treatment).Real-time ultrasound-guided histotripsy was applied to ablate either 100%tumor volume+up to 2 mm margin(n=9,complete treatment)or 50-75%tumor volume(n=6,partial treatment)by delivering 1-2 cycle histotripsy pulses at 100 Hz PRF(pulse repetition frequency)with p−≥30 MPa using a custom 1 MHz transducer.Rats were monitored weekly using MRI(magnetic resonance imaging)for 3 months or until tumors reached~25 mm.Results.MRI revealed effective post-histotripsy reduction of tumor burden with near-complete resorption of the ablated tumor in 14/15(93.3%)treated rats.Histopathology showed<5 mm shrunken,non-tumoral,fibrous tissue at the treatment site at 3 months.Rats with increased tumor burden(3/6 control and 1 partial treatment)were euthanized early by 2-4 weeks.In 3 other controls,histology revealed fibrous tissue at original tumor site at 3 months.There was no evidence of histotripsy-induced off-target tissue injury.Conclusion.Complete and partial histotripsy ablation resulted in effective tumor removal for 14/15 rats,with no evidence of local tumor progression or recurrence. | Tejaswi Worlikar Mishal Mendiratta-Lala Eli Vlaisavljevich Ryan Hubbard Jiaqi Shi Timothy L.Hall Clifford S.Cho Fred T.Lee Joan Greve Zhen Xu | 2020 | Biomedical Engineering Frontiers2020，1，1： | 1 |
| 7 | 对数字的感觉:不同技能水平儿童在操作心中算盘时手势角色的变化显示文摘珠心算涉及一系列熟练的象征操作脑中算盘的手势。本研究探讨算盘伴随思考手势(cothoughtgestures)的有益效果在不同技能水平个体和不同问题难度下如何变化。我们比较了6~8岁初级者(57人)、中级者(65人)、高级者(54人)在以下三种条件的心算表现:打算盘,不限制手势(自发手势)的心算,限制手势的心算。我们采用了混合主体设计,以问题难度和技能水平作为被试内自变量,条件作为被试间自变量。结果表明,不同技能水平的学习者在运算表现和手势准确度上有明显差异。学习者首先掌握了如何打算盘来运算,然后使用算盘手势来帮助心算。手的动作和手势的准确度表明,手势的有益效果可能与运动学习有关。初级者先熟练算盘,但在心算中表现差且手势准确度较低。中级者依靠手势来做心算,并且有精确的手部动作,但当手势受限制时表现差。高级者可以用精确的手势进行心算,并且在手势受限制时仍可获得同样好的分数。这些发现表明,对于中高级学习者来说,珠心算的视空间表征可以凭借算盘伴随思考手势的运动空间表征来补充,从而减少工作记忆负荷。 | Philip S.Cho Wing Chee So 毛冲(译) | 2020 | 珠算与珠心算2020，，4： | 0 |
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