[单项选择]某中学生，15岁。经骨髓穿刺检查诊断为"急性淋巴细胞白血病"，给以常规治疗，症状无缓解。医生告诉家长，此病目前尚无理想的治疗方法，医院正在尝试使用一种疗效不肯定、有一定风险的药物。其家长表示愿意做这种试验性治疗。但没有履行书面承诺手续。治疗二天后，病人病重，抢救无效，死亡。此后，家属否认曾同意这种治疗方案，称是"拿病人做试验"，要追究医生责任，于是造成医疗纠纷。就本案分析，医生做出选择的伦理依据是（）。
A. 研究目的是正确的
B. 符合知情同意的原则
C. 符合受试者利益的原则
D. 治疗期间，医生是积极负责的
E. 以上各点都符合临床医学研究原则，没有错误

{{B}} Reinventing the Table{{/B}}
An earth scientist has rejigged the periodic table to make chemistry simpler to teach to students.
{{U}} (46) {{/U}} But Bruce Railsback from the University of Georgia3 says he is the first to create a table that breaks with tradition and shows the ions of each element rather than just the elements themselves.
"I got tired of breaking my arms trying to explain the periodic table to earth students," he says, criss-crossing his hands in the air and pointing to different bits of a traditional table. {{U}} (47) {{/U}} But he has added contour lines to charge density, helping to explain which ions react with which.
"Geochemists just want an intuitive sense of what’s going on with the elements," says Albert Galy from the University of Cambridge4,{{U}} (48) {{/U}}.
{{U}} (