大肠杆菌的mRNA翻译效率决定于Shine-Dalgarno的局部结构(英文)

在大肠杆菌中,多胺对mRNA翻译的影响程度决定于Shine-Dalgarno(SD)序列局部结构.与信使RNA其他区域松散配对的SD序列的局部结构受多胺的扰动较大,其局部解链的概率也较大,因而SD序列结合到核糖体RNA上并启动蛋白质翻译的概率也较大,相反,则启动mRNA翻译的概率就会较小.基于此,建立一个简单数学模型来描述这一现象,即蛋白质的表达水平是与由多胺刺激而引起mRNA的SD序列局部暴露的概率相关的.结果显示,模型与实验结果相符的很好.

EC/beta(+) decay of six medium-heavy nuclei

Previous experimental results of (EC+beta(+)) decay for the medium-heavy nuclei reported by our group since 1996, including Er-153, Yb-157, Fr-209, Ce-128, Ce-130, and Pr-128 have been briefly summarized. The observed low-lying states in their daughter nuclei have been reviewed in a systematic way and compared with different model calculations. Finally, some questions have been put forward for further study and discussion.

Baryon magnetic moment and beta decay ratio in colored quark cluster model

Baryon magnetic moments of p, n, Sigma(+), Sigma(-), Xi(0), Xi(-) and the beta decay ratios (G(A)/G(V)) of n -> p, Sigma(-) -> n and Xi(0) -> Sigma(+) are calculated in a colored quark cluster model. With SU(3) breaking, the model gives a good fit to the experimental values of those baryon magnetic moments and the beta decay ratios. Our results show that the orbital motion has a significant contribution to the spin and magnetic moments of those baryons and the strange component. in nucleon is small.

beta-delayed fission of Ac-228

The basic process of an exotic decay mode namely P-delayed fission is simply introduced. The progress status of the study in the world is essentialized. The observation of P-delayed fission of Ac-228 is reported. The radium was radiochemically separated from natural thorium. Thin Ra sources in which Ac-228 was got through Ra-228 ->(beta-) Ac-228 were prepared for observing fission fragments from beta-delayed fission Ac-228. They exposed to the mica fission track detectors, and measured by an HPGe gamma-ray detector. The beta-delayed fission events of Ac-228 were observed and its beta-delayed fission probability was found to be (5 +/- 2) x 10(-12).