4 research outputs found
Additional file 1: of Millstone Exfoliation: a True Shear Exfoliation for Large-Size Few-Layer Graphene Oxide
Figure S1. SEM micrographs from MOG-30, MOG-60, MOG-90, and as-received graphite. Figure S2. TEM micrographs from MOG-30 and MOG-90. Figure S3. AFM micrographs from MOG-30 and MOG-90 (DOCX 2127 kb
Morphological Control over ZnO Nanostructures from Self-Emulsion Polymerization
Three different morphologies of ZnO
nanostructures, such as nanospheres,
nanorods, and nanoribbons, were controlled by tuning the ratio of
the Zn<sup>2+</sup> precursor to the 4VP monomer when polymerized
in aqueous medium utilizing self-emulsion polymerization. The amphiphilic
homopolymer (P4VP) acts as a template to form the ZnO/P4VP nanocomposite.
The aspect ratio of the nanostructures is strongly dependent on the
molar concentration of the Zn<sup>2+</sup> precursor and becomes higher
as its concentration increases. This results in different morphologies
that are consistently repeatable. Pure ZnO was obtained from the ZnO/P4VP
nanocomposites by calcination at 400 °C or by solvent washing.
The calcination of the nanocomposties resulted in different morphologies,
such as spherical, corolla shaped, and nanosheets. In addition, hexagonal
nanoblocks, nanorods, and nanoribbons were observed when the polymer
was removed from the nanocomposites by washing with chloroform. Removing
polymer by solvent washing is a very easy, cost-effective method and
has the potential for mass production of pure and highly crystalline
ZnO nanostructures with known and controllable morphologies. The nanocomposites
and pure ZnO nanostructures obtained after polymer removal were characterized
by transmission electron microscopy, high resolution transmission
electron microscopy, scanning electron microscopy, energy-dispersive
X-ray spectroscopy, and X-ray diffraction analyses, which confirmed
the crystalline nature of the ZnO
Exploration of the Mechanism for Self-Emulsion Polymerization of Amphiphilic Vinylpyridine
A rare
self-assembly behavior is observed in a hydrophilic monomer (4-vinylpyridine)
(4VP) when polymerized in water with a hydrophilic initiator that
results in the production of monodisperse polymeric nanoparticles
in a single step. This behavior mimics the behavior obtained with
the more commonly reported amphiphilic block copolymers. The synthesis
and self-assembly of homopolymer nanoparticle from 4VP without the
use of any cross-linker, stabilizing agent, surfactant, or polymeric
emulsifier are described along with fundamental aspects of the mechanism
of this polymerization. This facile and robust procedure enabled the
production of highly monodisperse P4VP nanoparticle with a tunable
size ranging from 80 to 445 nm. For the first time, we have investigated
the growth mechanism of these polymeric nanoparticles to clarify the
mechanism of polymeric nanoparticle formation. This work also provides
direct visible evidence through transmission electron microscopy (TEM)
images at the nanometer scale, which helps in obtaining a better understanding
of the mechanism of self-assembly. The effect of temperature on the
size of the polymeric nanoparticles was also examined along with the
effect of initiator, monomer, and solvent concentrations. We therefore
report a versatile and scalable process for the production of monodisperse
polymeric nanoparticles, which we call self-emulsion polymerization
(SEP)
Five nicotinic acetylcholine receptor subunits from the Morotoge shrimp, <i>Pandalopsis japonica</i>: cloning, tissue distribution, and functional expression in <i>Xenopus</i> oocytes
<div><p>The nicotinic acetylcholine receptor (nAChR) is a member of the ligand-gated ion channel (LGIC) family and is composed of five subunits arranged around a central pore. Expressed sequence tag screening and traditional cloning strategies revealed five full-length cDNAs encoding nAChR subunit homologs (Pajα3, Pajα10, Pajα11, Pajα12, and Pajβ1) in the Morotoge shrimp, <i>Pandalopsis japonica</i>. The nAChR subunits exhibited common structural characteristics, including a signal peptide sequence, a large N-terminal extracellular domain with conserved motifs for ligand binding (loops A–F), and a transmembrane (TM) domain with four hydrophobic TM motifs (TM1–TM4). Based on the conserved GEK motifs located just before TM2, all five nAChR subunits from <i>P. japonica</i> appear to be cation-selective ion channels. Among the five subunits, Pajα3 and Pajβ1 clustered together with insect core groups, whereas Pajα10, Pajα11, and Pajα12 were classified as a divergent group. Three distinct transcripts were identified in Pajα3, presumably due to alternative splicing between TM3 and TM4, which may be involved in channel formation with other subunits. All five nAChR subunits were expressed predominantly in neuronal tissues, including the brain, sinus gland/X-organ complex, thoracic ganglia, and abdominal ganglia, with no significant differences in subunit expression levels among the neuronal tissues. The five shrimp nAChR subunits could not be functionally expressed in <i>Xenopus</i> oocytes, but coexpression of Pajβ1 and rat α4 subunit (Rα4) formed functional channels responding to acetylcholine. Functional expression of vertebrate α subunit (Rα4) with invertebrate β1 subunit (Pajβ1) will expand our knowledge regarding the structural characteristics and molecular gating mechanism of invertebrate nAChRs.</p></div