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

In hydrocephalus, cerebrospinal fluid (CSF) builds up in the cranial cavity causing swelling of the head and potentially brain damage. A shunt to drain the fluid into a body cavity is now universally used, but failure is all too common. Techniques for ascertaining shunt failure are time-consuming, expertise-dependent, and often inconclusive. We report here an inline system that reliably and quantitatively measures the CSF flow rate. The system uses a single thermistor to both heat the surrounding and to sense the temperature. In the heating mode, the thermistor is subjected to a 5 s voltage pulse. In the sensing mode, it is part of a Wheatstone’s bridge, the output being proportional to temperature. The signal, Vi – Vf, which is the net change ΔV in the bridge output immediately before and after the heat pulse, depends both on the flow rate and the surrounding temperature. In vitro, a single equation, flow rate = 3.75 × 10–6 × ΔV(−9.568+1.088 Vi) provided good prediction for the flow rate, with 6.3% RMS r...

https://pubs.acs.org/doi/pdf/10.1021/acs.analchem.7b02034

Inline Shunt Flow Monitor for Hydrocephalus

Inline flow sensor for ventriculoperitoneal shunts: Experimental evaluation in swine

A self-monitoring flow-through heater. The heater has a wire inside a tube, and the wire heats and monitors the temperature of a fluid flowing through the tube. The wire has a high specific resistivity and a high temperature coefficient of resistance, so that monitoring the voltage across and/or the current flowing through the wire measures the mean temperature of the wire and of the fluid in the tube.

Self-monitoring flow-through heater

An apparatus (30) for scanning and detecting analytes in real time as they move through a separation conduit is provided. The apparatus generally comprises a stationary base (32), a separation conduit (33) mounted on said base, a carriage (35) movably supported on said base and configured to move along a length of said separation conduit, an integrated detector (37) mounted on the carriage and located immediately adjacent to the separation conduit, and a driver (39) moving the carriage relative to the base so that the integrated detector moves back and forth along the length of the separation conduit. A method for real time analysis of analytes as they move through a separation conduit is also provided.

Purnendu K. Dasgupta

Papers

Inline Shunt Flow Monitor for Hydrocephalus

Inline flow sensor for ventriculoperitoneal shunts: Experimental evaluation in swine

Self-monitoring flow-through heater

Method and apparatus for scanning detection

The reaction of nitrogen oxides with SO2 in aqueous aerosols