There is, I think, something ethereal about i —the square root of minus one. I remember first hearing about it at school. It seemed an odd beast at that time—an intruder hovering on the edge of reality.

Usually familiarity dulls this sense of the bizarre, but in the case of i it was the reverse: over the years the sense of its surreal nature intensified. It seemed that it was impossible to write mathematics that described the real world in …

I and i

抗原变异可使得多种致病微生物易于逃避宿主免疫应答。表达在感染红细胞表面的恶性疟原虫红细胞表面蛋白1（PfPMP1）与感染红细胞、内皮细胞、树突状细胞以及胎盘的单个或多个受体作用，在黏附及免疫逃避中起关键的作用。每个单倍体基因组var基因家族编码约60种成员，通过启动转录不同的var基因变异体为抗原变异提供了分子基础。

疟原虫var基因转换速率变化导致抗原变异[英]／Paul H, Robert P, Christodoulou Z, et al//Proc Natl Acad Sci U S A

https://pubs.rsc.org/en/content/articlepdf/2019/NP/C8NP00092A

Marine natural products.

基礎講座 電気泳動(Electrophoresis)

Microfluidic paper-based analytical devices (μPADs) are a new class of point-of-care diagnostic devices that are inexpensive, easy to use, and designed specifically for use in developing countries. (To listen to a podcast about this feature, please go to the Analytical Chemistry multimedia page at pubs.acs.org/page/ancham/audio/index.html.)

http://pubs.acs.org/doi/pdf/10.1021/ac9013989

Diagnostics for the Developing World: Microfluidic Paper-Based Analytical Devices

The G-class nerve agents, which include sarin, soman, and cyclosarin, react readily with nucleophilic reagents to produce fluoride. Thus, a chemosensing protocol has been designed for these agents that pairs the nucleophilic reactivity of oximates for generating fluoride with an autoinductive target amplification reaction to amplify the quantity of fluoride for facile colorimetric and fluorescent optical quantification. The chemosensing protocol was demonstrated by using the nerve agent surrogate diisopropyl fluorophosphate (DFP) and benzaldoxime as the nucleophile. Autoinductive fluoride amplification responds to fluoride released from DFP by amplifying the fluoride concentration and a yellow reporter molecule. The reporter is a conjugated oligomer with a nominal repeating unit that originates from 4-aminobenzaldehyde. Exposure of the amplified fluoride to a fluoride-specific ratiometric fluorescent reporter provides a fluorescent readout, in which three fluorophores are generated per fluoride. Both colorimetric and fluorescent readouts enable quantitative assays with low micromolar limits of detection for fluoride resulting from DFP. More importantly, this work demonstrates the successful merging of multiple complex reactions for achieving selective, sensitive, and quantitative chemosensing.

Coupling Activity‐Based Detection, Target Amplification, Colorimetric and Fluorometric Signal Amplification, for Quantitative Chemosensing of Fluoride Generated from Nerve Agents

Design of small molecule reagents that enable signal amplification via an autocatalytic, base-mediated cascade elimination reaction

https://www.rsc.org/suppdata/cc/c2/c2cc36861g/c2cc36861g.pdf

A thermally-stable enzyme detection assay that amplifies signal autonomously in water without assistance from biological reagents

This paper demonstrates that the gas-filled compartments in the packing material commonly called “bubble wrap” can be repurposed in resource-limited regions as containers to store liquid samples, and to perform bioanalyses. The bubbles of bubble wrap are easily filled by injecting the samples into them using a syringe with a needle or a pipet tip, and then sealing the hole with nail hardener. The bubbles are transparent in the visible range of the spectrum, and can be used as “cuvettes” for absorbance and fluorescence measurements. The interiors of these bubbles are sterile and allow storage of samples without the need for expensive sterilization equipment. The bubbles are also permeable to gases, and can be used to culture and store micro-organisms. By incorporating carbon electrodes, these bubbles can be used as electrochemical cells. This paper demonstrates the capabilities of the bubbles by culturing E. coli, growing C. elegans, measuring glucose and hemoglobin spectrophotometrically, and measuring fe...

/pdf/adaptive-use-of-bubble-wrap-for-storing-liquid-samples-and-36zsx9jhjg.pdf

Adaptive Use of Bubble Wrap for Storing Liquid Samples and Performing Analytical Assays

Smell of success: Reagent 1 provides the dual readouts of odor (ethanethiol) and fluorescence (derivative of 7-hydroxycoumarin) and can be used in down-selection assays based on smell and quantitative fluorescence assays of the samples that give a positive result. An important feature of 1 is the matched sensitivity of the two outputs. This reagent is designed for use in resource-limited settings and is demonstrated in assays that detect enzymes.

Scott T. Phillips

Papers

Coupling Activity‐Based Detection, Target Amplification, Colorimetric and Fluorometric Signal Amplification, for Quantitative Chemosensing of Fluoride Generated from Nerve Agents

Design of small molecule reagents that enable signal amplification via an autocatalytic, base-mediated cascade elimination reaction

A thermally-stable enzyme detection assay that amplifies signal autonomously in water without assistance from biological reagents

Adaptive Use of Bubble Wrap for Storing Liquid Samples and Performing Analytical Assays

Using Smell To Triage Samples in Point-of-Care Assays†