目的：应用无桥直接偶联模式合成靶向抗骨肿瘤偶联物甲氨蝶呤-偕二磷酸，并对其进行结构鉴定，了解其体外骨靶向性及对人成骨细胞毒性的影响。

Objective:To synthetize methotrexate-bisphosphonates conjugate by adaptation of directed couple method, and to identify its structure, bone target tropism and the effect of drug on osteoblast.

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别墅从朝向、构造、密封到无热桥连接，能经受德州中部的炎热气候。

The house is built to endure the hot climate of central Texas, from orientation to framing to airtightness to thermal-bridge free connections.

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在后期双著绿点染色体将形成一个桥，无著绿点染色体单体形成一断片，此两者均可记录下来。

At anaphase the dicentric chromatid will form a bridge and the acentric a fragment, both of which can be scored.

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