The manipulation of fluids in channels with dimensions of tens of micrometres--microfluidics--has emerged as a distinct new field. Microfluidics has the potential to influence subject areas from chemical synthesis and biological analysis to optics and information technology. But the field is still at an early stage of development. Even as the basic science and technological demonstrations develop, other problems must be addressed: choosing and focusing on initial applications, and developing strategies to complete the cycle of development, including commercialization. The solutions to these problems will require imagination and ingenuity.

The origins and the future of microfluidics

Nanoparticles containing magnetic materials, such as magnetite (Fe3O4), are particularly useful for imaging and separation techniques. As these nanoparticles are generally considered to be biologically and chemically inert, they are typically coated with metal catalysts, antibodies or enzymes to increase their functionality as separation agents. Here, we report that magnetite nanoparticles in fact possess an intrinsic enzyme mimetic activity similar to that found in natural peroxidases, which are widely used to oxidize organic substrates in the treatment of wastewater or as detection tools. Based on this finding, we have developed a novel immunoassay in which antibody-modified magnetite nanoparticles provide three functions: capture, separation and detection. The stability, ease of production and versatility of these nanoparticles makes them a powerful tool for a wide range of potential applications in medicine, biotechnology and environmental chemistry.

Intrinsic peroxidase-like activity of ferromagnetic nanoparticles

http://lovely-physics.persiangig.com/document/DLLME.pdf

Determination of organic compounds in water using dispersive liquid-liquid microextraction

For decades, studies of endocrine-disrupting chemicals (EDCs) have challenged traditional concepts in toxicology, in particular the dogma of “the dose makes the poison,” because EDCs can have effects at low doses that are not predicted by effects at higher doses. Here, we review two major concepts in EDC studies: low dose and nonmonotonicity. Low-dose effects were defined by the National Toxicology Program as those that occur in the range of human exposures or effects observed at doses below those used for traditional toxicological studies. We review the mechanistic data for low-dose effects and use a weight-of-evidence approach to analyze five examples from the EDC literature. Additionally, we explore nonmonotonic dose-response curves, defined as a nonlinear relationship between dose and effect where the slope of the curve changes sign somewhere within the range of doses examined. We provide a detailed discussion of the mechanisms responsible for generating these phenomena, plus hundreds of examples from...

/pdf/hormones-and-endocrine-disrupting-chemicals-low-dose-effects-2vn32zoqc8.pdf

Hormones and endocrine-disrupting chemicals: Low-dose effects and nonmonotonic dose responses

Background: Thyroid disease in pregnancy is a common clinical problem. Since the guidelines for the management of these disorders by the American Thyroid Association (ATA) were first published in 2...

https://www.thyca.org/download/document/486/PregnancyandPostpartum.pdf

2017 Guidelines of the American Thyroid Association for the Diagnosis and Management of Thyroid Disease During Pregnancy and the Postpartum

Flow-injection extraction photometry using conductometric phase recognition

Characterization of a constant current charge detector

A fully automated measurement system for ambient aerosol organic carbon, capable of unattended operation over extended periods, is described. Particles are collected in a cyclone with water as the collection medium. The collected sample is periodically aspirated by a syringe pump into a holding loop and then delivered to a wet oxidation reactor (WOR). Acid is added, and the WOR is purged to measure dissolved CO2 or inorganic carbonates (IC) as evolved CO2. The IC background can often be small and sufficiently constant to be corrected for, without separate measurement, by a blank subtraction. The organic material is now oxidized stepwise or in one step to CO2. The one-step oxidation involves UV-persulfate treatment in the presence of ozone. This treatment converts organic carbon (OC) to CO2, but elemental carbon is not oxidized. The CO2 is continuously purged from solution and collected by two sequential miniature diffusion scrubbers (DSs), a short DS preceding a longer one. Each DS consists of a LiOH-fill...

Semicontinuous Automated Measurement of Organic Carbon in Atmospheric Aerosol Samples

Feedback Based Continuous Flow Titrations with Electrogenerated Titrants

An electrodialytic buffer generator is described. The buffer generator may include a central buffer-generating channel having an inlet and outlet, a second chamber, and a third chamber. The buffer-generating channel, the second chamber, and the third chamber may each include an electrode. The buffer generator may also include a first ion exchange barrier and a second ion exchange barrier. The first ion exchange barrier can be disposed between the second chamber and the buffer- generating channel. The second ion exchange barrier can be disposed between the third chamber and the buffer-generating channel.

Purnendu K. Dasgupta

Papers

Flow-injection extraction photometry using conductometric phase recognition

Characterization of a constant current charge detector

Semicontinuous Automated Measurement of Organic Carbon in Atmospheric Aerosol Samples

Feedback Based Continuous Flow Titrations with Electrogenerated Titrants

Three- electrode buffer generator and method