N-9 Alkylation of purines via light-promoted and metal-free radical relay

A light-promoted approach to the synthesis of N-9 alkylated purine nucleoside derivatives has been developed.     

极紫外、X射线和中子薄膜光学元件与系统

极紫外、X射线和中子光学为现代科学的发展提供了高精度的观测手段,但这些手段的实现需要大量高性能薄膜光学元件和系统的支撑。由于短波长和材料光学常数的限制,短波光学元件的结构、性能和制作技术明显区别于长波光学元件。近二十年来,同济大学精密光学工程技术研究所建立了以短波反射镜为基底的精密加工检测平台,发展了超薄薄膜界面生长调控方法和大尺寸薄膜镀制技术,提出了高效率/高分辨率多层膜微纳结构的衍射理论和制备方法,初步阐明了短波辐照损伤的物理机制,形成了短波薄膜和晶体聚焦成像系统的高精度全流程研制技术,并将该技术成功应用于国内和国际短波光子大科学装置中。本文简要介绍本课题组在上述短波元件和系统领域中的研究进展。     

自由空间内悬挂气泡破碎时的声学特性

气泡破碎是自然界和工、农业生产中常见的现象。气泡在破碎过程中因气流流动而产生强烈的扰动,导致破碎时产生强烈的气动声学。该文采用实验和理论相结合的方式对自由空间内悬挂气泡破碎时的声学特性进行了研究。研究发现：随着液体表面张力系数的增加,声发射的特征振幅逐渐增大;随着气泡半径的增加,声发射的特征振幅逐渐增大。理论计算结果与实验结果基本吻合。     

微波促进的非环核苷类化合物的合成

以嘌呤碱基和各种α,β-不饱和醛为原料,用三乙胺作为催化剂,在微波的促进下,通过Michael加成反应和原位还原,高效地合成了一系列非环核苷类新化合物.得到的目标化合物通过核磁共振图谱、高分辨质谱进行了确认.     

ESTIMATION OF SCATTER MATRIX BASED ON i．i．d． SAMPLE FROM ELLIPTICAL DISTRIBUTIONS

ＥＥＳＴＩＭＡＴＩＯＮＯＦＳＣＡＴＴＥＲＭＡＴＲＩＸＢＡＳＥＤＯＮｉ．ｉ．ｄ．ＳＡＭＰＬＥＦＲＯＭＥＬＬＩＰＴＩＣＡＬＤＩＳＴＲＩＢＵＴＩＯＮＳ￥ＦＡＮＧＫＡＩＴＡＩ（方开泰）（ＩｎｓｔｉｔｕｔｅｏｆＡＰＰｌｉｅｄＭａｔｈｅｍａｔｉｃｓ,ｔｈｅＣｈｉ...     

Bacterial Cytochrome P450 Catalyzed Post-translational Macrocyclization of Ribosomal Peptides**

Ribosomally synthesized and post-translationally modified peptides (RiPPs) are a fascinating group of natural products that exhibit diverse structural features and bioactivities. P450-catalyzed RiPPs stand out as a unique but underexplored family. Herein, we introduce a rule-based genome mining strategy that harnesses the intrinsic biosynthetic principles of RiPPs, including the co-occurrence and co-conservation of precursors and P450s and interactions between them, successfully facilitating the identification of diverse P450-catalyzed RiPPs. Intensive BGC characterization revealed four new P450s, KstB, ScnB, MciB, and SgrB, that can catalyze the formation of Trp-Trp-Tyr (one C−C and two C−N bonds), Tyr-Trp (C−C bond), Trp-Trp (C−N bond), and His-His (ether bond) crosslinks, respectively, within three or four residues. KstB, ScnB, and MciB could accept non-native precursors, suggesting they could be promising starting templates for bioengineering to construct macrocycles. Our study highlights the potential of P450s to expand the chemical diversity of strained macrocyclic peptides and the range of biocatalytic tools available for peptide macrocyclization.