Antiviral enantiomers of a bisindole alkaloid with a new carbon skeleton from the roots of Isatis indigotica

A pair of indole alkaloid enantiomers with a novel bisindolylacetamide skeleton, insatindibisindolamides A and B（1a and 1b）, was isolated from an aqueous extract of Isatis indigotica roots. The enantiomers were separated by chiral HPLC. Their structures and absolute configurations were elucidated by extensive spectroscopic analysis, including 2D NMR, X-ray crystallography, and electronic CD（ECD） calculation. The proposed biosynthetic pathway and preliminary investigations of the biological activity of compounds 1a and 1b are also discussed.

Antiviral stereoisomers of 3,5-bis(2-hydroxybut-3-en-1-yl)-1,2,4-thiadiazole from the roots of Isatis indigotica

Four stereoisomers of 3,5-bis（2-hydroxybut-3-en-1-yl）-l,2,4-thiadiazole, named insatindigothiadia- zoles A-D （1a-1d）, were isolated from the roots oflsatis indigotica. Their structures were determined by spectroscopic analysis; specifically, the absolute configurations were assigned by using the MPA determination rule based on △δrs values of MPA esters, and supported by electronic CD （ECD） calculations. Proposed biosynthetic pathways and preliminary investigations of the biological activities of la-1d against influenza virus A （H3N2）, Coxsackie virus B3, and/or HSV-1 are also discussed.

Principles and applications of high-speed single-pixel imaging technology

单像素成像技术具有利用一个单像素探测器获取高分辨图像的能力,近十年来得到广泛关注。该技术已应用于多个领域,如核磁共振成像、航天遥感、太赫兹成像和高光谱成像。与传统相机相比,单像素相机可以实现图像压缩和超宽的频谱工作范围。然而,单像素相机的成像速度受到数字微镜阵列和图像压缩程度限制,导致其时间分辨率较低(毫秒量级)。因此,观察显微成像中的高速动态现象对于单像素相机而言是巨大挑战。最近,基于光子时间拉伸的高速单像素成像技术被提出,其远超普通相机的成像速度也得到验证。本文介绍了光子时间拉伸技术的原理和应用,给出了高速单像素相机的结构,并通过实验证实利用该相机可实现高速和高吞吐量细胞流式分析,最后,讨论了高速单像素相机的局限和应用潜力。