7 research outputs found
SR-FTIR micrographs.
<p>(A) Micrographs and FTIR spectral images of amide I and amide II bands, derived from 128 SR-FTIR spectra of cross-sectioned grey hair samples (5 μm thick) treated with water (control) and ash extract (ash-treated); (B) and (C) relative peak areas (%) of parallel beta-strand, unordered structure, alpha-helix, beta-turns, anti-parallel beta-strand and lipid esters distributed in the cuticle (black), cortex (white) and medulla (grey) regions deconvoluted from the SR-FTIR spectra of the hair samples treated with water and ash extract, respectively. All hair samples were treated for 1 h at 25±2°C, blotted-dried and stored at 55%RH until use. (the cuticle (marked ∪), the cortex (co) and the medulla (m), * <i>p</i> < 0.05, compared to the control).</p
CIE color scale assessment.
<p>(A) Average CIE Lab colorimetric data of grey hair (across 50 shafts/measurement, n = 3) 1-h treated with water (clear columns), ash extract (light grey columns), dye solution (dark grey columns) and ash extract followed by dye solution (black columns), 1 h for each treatment and (B) overall color difference (DE*) of each treatment, calculated by <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0199696#pone.0199696.e002" target="_blank">Eq (2)</a>; L* = darkness(0)/lightness(100), a* = green(-)/red(+) and b* = blue(-)/yellow(+).</p
Sulfur K-edge XANE spectra.
<p>Sulfur <i>K</i>-edge XANES spectra recorded directly from the grey hair samples, 30-min treated with water, 30% ammonia solution (NH<sub>3</sub>(aq)), ash extract (Ash) and 3% hydrogen peroxide solution (H<sub>2</sub>O<sub>2</sub>) at 25 ± 1°C.</p
Anthocyanin adsorption.
<p>Total anthocyanin content (as C3GE) adsorbed by grey hair (μg/mg of hair) and concentration of total anthocyanin contents at initial (conc, μg/ml) compared ash-pretreated grey hair (<b>−●−</b>) and control (<sup><b>…</b></sup><b>○</b><sup><b>…</b></sup>), at 25 ± 2 °C for 1 h, n = 5 each and error bars = standard deviations and * = <i>p</i> < 0.05.</p
SEM and AFM images.
<p>Representative images from scanning electron microscopy (2000× magnification) (left column) and atomic force microscopy topography (contact mode, 400 N force on the cantilever tip in a 40 μm × 4 μm area randomly integrated for overlapping distances of 3 cuticle cells within 5 μm × 5μm) (right column) of hair samples treated with water (pH 6.7), ash extract (pH 12), KOH (pH 12) and ammonia solution (NH₃(aq), pH 12) at 55% RH and 25±2°C.</p
Kinetically Controlled Autocatalytic Chemical Process for Bulk Production of Bimetallic Core–Shell Structured Nanoparticles
Although bimetallic core@shell structured nanoparticles (NPs) are achieving prominence due to their multifunctionalities and exceptional catalytic, magnetic, thermal, and optical properties, the rationale underlying their design remains unclear. Here we report a kinetically controlled autocatalytic chemical process, adaptable for use as a general protocol for the fabrication of bimetallic core@shell structured NPs, in which a sacrificial Cu ultrathin layer is autocatalytically deposited on a dimensionally stable noble-metal core under kinetically controlled conditions, which is then displaced to form an active ultrathin metal-layered shell by redox–transmetalation. Unlike thermodynamically controlled under-potential deposition processes, this general strategy allows for the scaling-up of production of high-quality core–shell structured NPs, without the need for any additional reducing agents and/or electrochemical treatments, some examples being Pd@Pt, Pt@Pd, Ir@Pt, and Ir@Pd. Having immediate and obvious commercial potential, Pd@Pt NPs have been systematically characterized by <i>in situ</i> X-ray absorption, electrochemical-FTIR, transmission electron microscopy, and electrochemical techniques, both during synthesis and subsequently during testing in one particularly important catalytic reaction, namely, the oxygen reduction reaction, which is pivotal in fuel cell operation. It was found that the bimetallic Pd@Pt NPs exhibited a significantly enhanced electrocatalytic activity, with respect to this reaction, in comparison with their monometallic counterparts
Live Templates of a Supramolecular Block Copolymer for the Synthesis of Ordered Nanostructured TiO<sub>2</sub> Films via Guest Exchange
In this work, we
introduce a facile method based on host–guest chemistry to
synthesize a range of nanostructured TiO<sub>2</sub> materials using
supramolecular templates of a dendron-jacketed block copolymer (DJBCP).
The DJBCP is composed of amphiphilic dendrons (4′-(3,4,5-tridodecyloxybenzoyloxy)benzoic
acid, TDB) selectively incorporated into a P4VP block of polystyrene-<i>block</i>-poly(4-vinylpyridine) (PS-<i>b</i>-P4VP) via hydrogen bonding. The PS-<i>b</i>-P4VP host
acts as a structure-directing template, while the guest molecules
(TDB) assist the self-assembly nanostructures and zone-axis alignment,
resulting in the nanostructured template of vertically oriented cylinders
formed via successive phase transformations from <i>Im</i>3̅<i>m</i> to <i>R</i>3̅<i>m</i> to <i>P</i>6<i>mm</i> upon thermal annealing
in the doctor-blade-cast film. The guest
molecules subsequently direct the titania precursors into the P4VP
domains of the templates via supramolecular guest exchange during
immersion of the film in a designated precursor solution containing
a P4VP-selective solvent. The subsequent UV irradiation step leads
to the formation of PS-<i>b</i>-P4VP/TiO<sub>2</sub> hybrids. Finally, removal of the host template by calcination leaves
behind mesoporous channels and makes sacrifices to be a carbon source
for carbon-doping TiO<sub>2</sub> materials. Various TiO<sub>2</sub> nanoarchitectures, namely, vertical and wiggly micrometer-length
channels, inverse opals, fingerprint-like channels, heterogeneous
multilayers, and nanotubes, have been fabricated by highly tunable
DJBCP nanostructures