Fluoropolymer Nanoparticles Prepared Using Trifluoropropene Telomer Based Fluorosurfactants.

A fluorosurfactant based on 3,3,3-trifluoropropene (TFP) telomer was synthesized as an environmentally friendly alternative to perfluorooctanoic acid (PFOA) using TFP and 2-iodoperfluoropropane ((CF)CF-I) as starting materials. TFP telomerization was initiated by addition of di--butylperoxide in the presence of (CF)CF-I as a chain transfer agent. The surfactant was obtained by modification of the iodine end-group on the TFP telomer to form an allylic functionality followed by the addition of thioglycolic acid via a thiol-ene reaction.

A monolithic immersion metalens for imaging solid-state quantum emitters.

Quantum emitters such as the diamond nitrogen-vacancy (NV) center are the basis for a wide range of quantum technologies. However, refraction and reflections at material interfaces impede photon collection, and the emitters' atomic scale necessitates the use of free space optical measurement setups that prevent packaging of quantum devices. To overcome these limitations, we design and fabricate a metasurface composed of nanoscale diamond pillars that acts as an immersion lens to collect and collimate the emission of an individual NV center.

Nanocardboard as a nanoscale analog of hollow sandwich plates.

Corrugated paper cardboard provides an everyday example of a lightweight, yet rigid, sandwich structure. Here we present nanocardboard, a monolithic plate mechanical metamaterial composed of nanometer-thickness (25-400 nm) face sheets that are connected by micrometer-height tubular webbing. We fabricate nanocardboard plates of up to 1 centimeter-square size, which exhibit an enhanced bending stiffness at ultralow mass of ~1 g m.

Investigation of a novel fluorinated surfactant-based system for the design of spherical wormhole-like mesoporous silica.

In contrast to hydrogenated based systems that led to many studies, fluorinated surfactants have been little reported. Thanks to their high chemical and thermal stability, these compounds are considered as suitable candidates for the synthesis of porous materials with an enhanced hydrothermal stability. This study reports the synthesis of a new fluorinated surfactant, 2-trifluoromethyl-7,7,8,8,9,9,10,10,11,11,12,12,12-tridecafluoro-4-thia-1-dodecanoic acid (FSC) obtained from the thiol-ene radical addition of 3,3,4,4,5,5,6,6,7,7,8,8,8-tridecafluoro-1-octanethiol onto 2-trifluoromethyl acrylic acid in 85% yield.

The Nanolithography Toolbox.

This article introduces in archival form the Nanolithography Toolbox, a platform-independent software package for scripted lithography pattern layout generation. The Center for Nanoscale Science and Technology (CNST) at the National Institute of Standards and Technology (NIST) developed the Nanolithography Toolbox to help users of the CNST NanoFab design devices with complex curves and aggressive critical dimensions. Using parameterized shapes as building blocks, the Nanolithography Toolbox allows users to rapidly design and layout nanoscale devices of arbitrary complexity through scripting and programming.

F DOSY diffusion-NMR spectroscopy of fluoropolymers.

A new pulse sequence for obtaining F detected DOSY (diffusion ordered spectroscopy) spectra of fluorinated molecules is presented and used to study fluoropolymers based on vinylidene fluoride and chlorotrifluoroethylene. The performance of F DOSY NMR experiments (and in general any type of NMR experiment) on fluoropolymers creates some unique complications that very often prevent detection of important signals. Factors that create these complications include: (1) the presence of many scalar couplings among H, F and C; (2) the large magnitudes of many F homonuclear couplings (especially J ); (3) the large F chemical shift range; and (4) the low solubility of these materials (which requires that experiments be performed at high temperatures).

A Versatile Strategy to Synthesize Perfluoropolyether-Based Thermoplastic Fluoropolymers by Alkyne-Azide Step-Growth Polymerization.

Perfluoropolyether (PFPE)-based thermoplastic fluoropolymers are synthesized by A2 + B2 step-growth polymerization between PFPE-diyne and fluorinated diazides. This versatile method allows synthesizing PFPE-based materials with tunable physicochemical properties depending on the exact nature of the fluorinated segment of the diazide precursor. Semicrystalline or amorphous materials endowed with high thermostability (≈300 °C under air) and low glass transition temperature (≈-100 °C) are obtained, as confirmed by differential scanning calorimetry, thermogravimetry, and rheometry.

Synthesis of Chlorotrifluoroethylene-Based Block Copolymers by Iodine Transfer Polymerization.

Various fluorinated macro-chain transfer agents (CTAs) based on vinylidene fluoride (VDF), chlorotrifluoroethylene (CTFE), or CTFE and vinylidene chloride (VDC), were synthesized by iodine transfer polymerization (ITP). These macro-CTAs were involved in a further ITP reaction that led to the synthesis of original CTFE-based block copolymers exhibiting molecular weight ranging from 2500 to 40000 g/mol and endowed with high thermal stabilities (decomposition temperature at 10% weight loss of ca. 380 °C, under air).

The effect of economic, physical, and psychological abuse on mental health: a population-based study of women in the Philippines.

Background. The comparative effect of economic abuse and other forms of abuse in predicting depression and other mental health disorders has not been previously investigated despite its relevance for mental illness prevention. Objective.

Synthesis of fluorinated telechelic diols based on 3,3,3-trifluoropropene as precursors of well-defined fluoropolymers.

Original fluorinated α,ω-diols containing 3,3,3-trifluoropropene (TFP) units were synthesized. The first step dealt with the radical telomerization of TFP with 1,6-diiodoperfluorohexane. Isolated I(TFP)RF(TFP)I diadduct was subsequently reacted with ethylene, and then a two-step hydrolysis gave rise to α,ω-diols in 25% overall yield.

Access to and use of health services among undocumented Mexican immigrants in a US urban area.

Objectives: We assessed access to and use of health services among Mexican-born undocumented immigrants living in New York City in 2004.

Methods: We used venue-based sampling to recruit participants from locations where undocumented immigrants were likely to congregate. Participants were 18 years or older, born in Mexico, and current residents of New York City.

Hunger and health among undocumented Mexican migrants in a US urban area.

Objectives: To measure the occurrence and correlates of hunger and to evaluate the association between hunger and three health indicators among undocumented Mexican immigrants.

Design: Non-probability cross-sectional sample.

Setting: Neighbourhoods within New York City.

Investigation of the specificity of an alpha-L-arabinofuranosidase using C-2 and C-5 modified alpha-L-arabinofuranosides.

The synthesis of three novel glycosyl donors presenting the same scaffold as alpha-L-arabinofuranose but modified at the C-2 or C-5 positions has been achieved. Furthermore, chemoenzymatic syntheses using the alpha-L-arabinofuranosidase AbfD3 and these unnatural furanosides were investigated. The use of the novel p-nitrophenyl furanoside donors revealed that AbfD3 can perform transglycosylation with the C-5 deoxygenated donor but not with the C-2 modified one.

Thioimidoyl furanosides as first inhibitors of the alpha-L-arabinofuranosidase AbfD3.

Two sets of five thioimidoyl alpha-L-arabino- and beta-D-galactofuranosides were designed, synthesized and subjected to docking studies to evaluate their ability to be recognized by the active site of the alpha-L-arabinofuranosidase AbfD3. Further in vitro assays showed that the targeted furanosides are the first potent inhibitors of this furanosyl hydrolase and that the most efficient one, the thiazolyl alpha-L-arabinofuranoside 1, is a competitive inhibitor having a KI of 1.4 microM.