Search results for "silo"

Polylactic is a Sustainable, Low Absorption, Low Autofluorescence Alternative to Other Plastics for Microfluidic and Organ-on-Chip Applications

2020

Organ-on-chip (OOC) devices are miniaturized devices replacing animal models in drug discovery and toxicology studies. The majority of OOC devices are made from polydimethylsiloxane (PDMS), an elastomer widely used in microfluidic prototyping, but posing a number of challenges to experimentalists, including leaching of uncured oligomers and uncontrolled absorption of small compounds. Here we assess the suitability of polylactic acid (PLA) as a replacement material to PDMS for microfluidic cell culture and OOC applications. We changed the wettability of PLA substrates and demonstrated the functionalization method to be stable over a time period of at least 9 months. We successfully cultured …

A biostable, anti-fouling zwitterionic polyurethane-urea based on PDMS for use in blood-contacting medical devices.

2020

Polydimethylsiloxane (PDMS) is commonly used in medical devices because it is non-toxic and stable against oxidative stress. Relatively high blood platelet adhesion and the need for chemical crosslinking through curing, however, limit its utility. In this research, a biostable PDMS-based polyurethane-urea bearing zwitterion sulfobetaine (PDMS-SB-UU) was synthesized for potential use in the fabrication or coating of blood-contacting devices, such as a conduits, artificial lungs, and microfluidic devices. The chemical structure and physical properties of synthesized PDMS-SB-UU were confirmed by (1)H-nuclear magnetic resonance ((1)H-NMR), X-ray diffraction (XRD), and uniaxial stress-strain cur…

Palladium-catalyzed formation and reactions of iodo- and bromosiloxane intermediates

2012

Polysiloxanes are useful materials because of their functionality, such as high thermal stability, electrical resistance, and hydrophobicity. In this regard, we studied palladium-catalyzed formation of iodo-and bromopolysiloxanes from two types of hydrosiloxanes, alpha,omega-dihydropoly(dimethylsiloxane) (1) and cyclotetra(hydromethylsiloxane) (2), and their reactions. Treatment of 1 with mixtures of cyclic ethers or lactones and MeI or allylBr in the presence of a catalytic amount of PdCl2 gave the corresponding alpha,omega-bis(haloalkoxy and haloalkanoyloxy) poly(dimethylsiloxane)s in good yields, via iodo-and bromopoly(dimethylsiloxane) intermediates. Transformation of the iodobutoxy-ter…

Polydimethylsiloxane (silicone rubber) brooch as a personal passive air sampler for semi-volatile organic compounds

2018

Exposure assessments conducted using a personal sampler include the contribution of human activities to exposure that is neglected when using a stationary air sampler. This study evaluated the uptake characteristics and application of the polydimethylsiloxane (PDMS or silicone rubber) brooch as a personal passive air sampler (PPAS) for measuring concentrations of two groups of semi-volatile organic compounds (SVOCs), namely phthalates and organophosphate esters (OPEs), indoors in proximity to the breathing zone. Uptake rates of the PDMS brooch were calibrated against a personal low volume active air sampler (PLV-AAS) co-deployed on each of five study participants working in offices for 8 hs…

Repercusión de los factores clínicos y microbiológicos en la selección de la especie causal de candidemia en el paciente crítico adulto en un hospita…

2017

ANTECEDENTES: Las micosis invasoras son infecciones emergentes asociadas a elevada morbi-mortalidad en pacientes críticos, siendo la candidiasis invasora (con o sin candidemia asociada) la más frecuente en todas las latitudes. Los pacientes ingresados en Unidades de Críticos (UC), debido a sus enfermedades de base y al desarrollo de técnicas diagnósticas y terapéuticas cada día más agresivas, tienen un elevado riesgo de presentar candidiasis invasora. Aunque Candida albicans es el agente etiológico de candidemia más habitual en todos los hospitales, en las últimas décadas se ha observado un aumento en la incidencia de especies no albicans. Este cambio en la etiología de la candidemia tambié…

Ordered networks of rat hippocampal neurons attached to silicon oxide surfaces.

2001

The control of neuronal cell position and outgrowth is of fundamental interest in the development of applications ranging from cellular biosensors to tissue engineering. We have produced rectangular networks of functional rat hippocampal neurons on silicon oxide surfaces. Attachment and network formation of neurons was guided by a geometrical grid pattern of the adhesion peptide PA22-2 which matches in sequence a part of the A-chain of laminin. PA22-2 was applied by contact printing onto the functionalised silicon oxide surface and was immobilised by hetero-bifunctional cross-linking with sulfo-GMBS. Geometric pattern matching was achieved by microcontact printing using a polydimethylsiloxa…

Mating-induced differential peptidomics of neuropeptides and protein hormones in Agrotis ipsilon moths

2018

International audience; In many insects, mating induces drastic changes in male and female responses to sex pheromones or host-plant odors. In the male moth Agrotis ipsilon, mating induces a transient inhibition of behavioral and neuronal responses to the female sex pheromone. As neuropeptides and peptide hormones regulate most behavioral processes, we hypothesize that they could be involved in this mating-dependent olfactory plasticity. Here we used next-generation RNA sequencing and a combination of liquid chromatography, matrix assisted laser desorption ionization time-of-flight (MALDI-TOF) mass spectrometry, and direct tissue profiling to analyze the transcriptome and peptidome of diffe…

From Molecules to Systems: Sol-Gel Microencapsulation in Silica-Based Materials

2010

Impact of acidic/hydrothermal treatment on pore structural and chromatographic properties of porous silicas

1991

Abstract A series of commercial silicas and a laboratory made product were subjected to acidic/hydrothermal treatment with solutions of HCI, HNO3, H2SO4 and HF. The concentration of acid and the temperature and duration of treatment were varied. The specific surface area, content of metal impurities, types and concentration of surface hydroxyl and siloxane groups and crystallinity were determined for native and treated silicas. Only changes in the structural order of the surface could be assessed by means of 19Si cross-polarization magic angle spinning NMR spectrometry and electron diffraction. The native and acid-treated silicas were surface modified to n-octyl derivatives and tested under…

Development of standard operation procedures for the manufacture of n-octadecyl bonded silicas as packing material in certified reference columns for…

2004

The development of standard operation procedures for the manufacture of a n-octadecyl bonded spherical silica packing from partially condensed tetraethoxysilane as silica source is described. The synthesis comprises five intermediate products and six synthesis steps which were examined according to their reproducibility and robustness. The results led to the optimisation of the manufacturing process for a n-octadecyl bonded silica. Correlations were drawn between the dynamic viscosity of the poly(ethoxy)siloxane (PES), the synthesis parameters, the resulting pore structural properties and particle size distribution of the silicas. Validated procedures were developed to manufacture spherical…