27 research outputs found
Localized Mechanical Stress Induced Ionic Redistribution in a Layered LiCoO<sub>2</sub> Cathode
Controlling
the transport of ions within electrodes is highly desirable for the
operation of rechargeable ion batteries. Here, for the first time,
we report the role of mechanical stress in controlling the redistribution
of lithium ions in a layered LiCoO<sub>2</sub> electrode at a resolution
of ∼100 nm. Under a higher stress field, more active redistribution
of lithium ions was observed along the grain boundaries than the interiors
of the layered LiCoO<sub>2</sub>. The dynamic force ramping test proved
the external stress field (<100 nN) is capable of inducing the
resistive-switching effect of the layered LiCoO<sub>2</sub>. The comparison
test on the highly ordered pyrolytic graphite (HOPG) substrate further
demonstrated the improved current responses from the layered LiCoO<sub>2</sub> resulted from the deficiency of lithium ions, rather than
the increase of tip–sample contact area. Our findings will
pave the road for a full understanding of how mechanical stimulus
can affect the distribution of ions in the layered electrodes of rechargeable
ion batteries
MOESM1 of An optimized rapid bisulfite conversion method with high recovery of cell-free DNA
Additional file 1: Figure. An example of a ddPCR assay for absolute quantification of DNA copies. The designed ddPCR reaction produced an excellent separation between positive droplets(top) and negative droplets(bottom). The amplitude threshold of the positive ddPCR reaction was set as 4000Â RFU manually. The positive droplets above the threshold line determines the starting concentration of the target DNA molecule in units of copies/ÂľL input from the sample
MOESM2 of An optimized rapid bisulfite conversion method with high recovery of cell-free DNA
Additional file 2: Data. Bisulfite sequencing and DNA methylation data
Preformed Seeds Modulate Native Insulin Aggregation Kinetics
Insulin aggregates under storage
conditions via disulfide interchange
reaction. It is also known to form aggregates at the site of repeated
injections in diabetes patients, leading to injection amyloidosis.
This has fueled research in pharmaceutical and biotechnology industry
as well as in academia to understand factors that modulate insulin
stability and aggregation. The main aim of this study is to understand
the factors that modulate aggregation propensity of insulin under
conditions close to physiological and measure effect of “<i>seeds</i>” on aggregation kinetics. We explored the aggregation
kinetics of insulin at pH 7.2 and 37 °C in the presence of disulfide-reducing
agent dithiothreitol (DTT), using spectroscopy (UV–visible,
fluorescence, and Fourier transform infrared spectroscopy) and microscopy
(scanning electron microscopy, atomic force microscopy) techniques.
We prepared insulin “<i>seeds</i>” by incubating
disulfide-reduced insulin at pH 7.2 and 37 °C for varying lengths
of time (10 min to 12 h). These seeds were added to the native protein
and nucleation-dependent aggregation kinetics was measured. Aggregation
kinetics was fastest in the presence of 10 min seeds suggesting they
were <i>nascent.</i> Interestingly, <i>intermediate</i> seeds (30 min to 4 h incubation) resulted in formation of transient
fibrils in 4 h that converted to amorphous aggregates upon longer
incubation of 24 h. Overall, the results show that insulin under disulfide
reducing conditions at pH and temperature close to physiological favors
amorphous aggregate formation and seed “maturity” plays
an important role in nucleation dependent aggregation kinetics
Anisotropic Friction of Wrinkled Graphene Grown by Chemical Vapor Deposition
Wrinkle
structures are commonly seen on graphene grown by the chemical vapor
deposition (CVD) method due to the different thermal expansion coefficient
between graphene and its substrate. Despite the intensive investigations
focusing on the electrical properties, the nanotribological properties
of wrinkles and the influence of wrinkle structures on the wrinkle-free
graphene remain less understood. Here, we report the observation of
anisotropic nanoscale frictional characteristics depending on the
orientation of wrinkles in CVD-grown graphene. Using friction force
microscopy, we found that the coefficient of friction perpendicular
to the wrinkle direction was ∼194% compare to that of the parallel
direction. Our systematic investigation shows that the ripples and
“puckering” mechanism, which dominates the friction
of exfoliated graphene, plays even a more significant role in the
friction of wrinkled graphene grown by CVD. The anisotropic friction
of wrinkled graphene suggests a new way to tune the graphene friction
property by nano/microstructure engineering such as introducing wrinkles
Online Characterization of Mixed Plastic Waste Using Machine Learning and Mid-Infrared Spectroscopy
To recycle the mixed plastic wastes (MPW), it is important
to obtain
the compositional information online in real time. We present a sensing
framework based on a convolutional neural network (CNN) and mid-infrared
spectroscopy (MIR) for the rapid and accurate characterization of
MPW. The MPW samples are placed on a moving platform to mimic the
industrial environment. The MIR spectra are collected at the rate
of 100 Hz, and the proposed CNN architecture can reach an overall
prediction accuracy close to 100%. Therefore, the proposed method
paves the way toward the online MPW characterization in industrial
applications where high throughput is needed
Complex-Mediated Synthesis of Tantalum Oxyfluoride Hierarchical Nanostructures for Highly Efficient Photocatalytic Hydrogen Evolution
In
this work, we have, for the first time, developed a facile wet-chemical
route to obtain a novel photocatalytic material of tantalum oxyfluoride
hierarchical nanostructures composed of amorphous cores and single
crystalline TaO<sub>2</sub>F nanorod shells (ACHNs) by regulating
the one-step hydrothermal process of TaF<sub>5</sub> in a mixed solution
of isopropanol (i-PrOH) and H<sub>2</sub>O. In this approach, elaborately
controlling the reaction temperature and volume ratio of i-PrOH and
H<sub>2</sub>O enabled TaF<sub>5</sub> to transform into intermediate
coordination complex ions of [TaOF<sub>3</sub>·2F]<sup>2–</sup> and [TaF<sub>7</sub>]<sup>2–</sup>, which subsequently produced
tantalum oxyfluoride ACHNs via a secondary nucleation and growth due
to a stepwise change in hydrolysis rates of the two complex ions.
Because of the unique chemical composition, crystal structure and
micromorphology, the as-prepared tantalum oxyfluoride ACHNs show a
more negative flat band potential, an accelerated charge transfer,
and a remarkable surface area of 152.4 m<sup>2</sup> g<sup>–1</sup> contributing to increased surface reaction sites. As a result, they
exhibit a photocatalytic activity for hydrogen production up to 1.95
mmol h<sup>–1</sup> g<sup>–1</sup> under the illumination
of a simulated solar light without any assistance of co-catalysts,
indicating that the as-prepared tantalum oxyfluoride ACHNs are a novel
promising photocatalytic material for hydrogen production
Narrowing Plasmon Resonance Linewidth of Au Nanodome Lattices
Gold hollow nanodomes
arranged in hexagonal lattices support surface plasmon polaritons
(SPPs) propagating at air–Au interface. The cross-sectional
heights of the continuous and hierarchical hexagonal nanodome arrays
can be altered by a simple thermal treatment, and the change in nanodome
size leads to a significant linewidth narrowing of plasmon resonance
because of reduced scattering loss. Taking the variation in the SPP
intensities into account, the surface modulation depth is found to
be around 100 nm for achieving a longer propagation length of SPP
Comparison among the subjects’ genotypes and symptoms among samples.
<p>+: duplication, −: deletion, n: normal. Losing or gain in the whole segments leads to diseases. REPD variations may not leads to diseases but impacts SOX7 which is related to CHD.</p
Characteristic Work Function Variations of Graphene Line Defects
Line
defects, including grain boundaries and wrinkles, are commonly seen
in graphene grown by chemical vapor deposition. These one-dimensional
defects are believed to alter the electrical and mechanical properties
of graphene. Unfortunately, it is very tedious to directly distinguish
grain boundaries from wrinkles due to their similar morphologies.
In this report, high-resolution Kelvin potential force microscopy
(KPFM) is employed to measure the work function distribution of graphene
line defects. The characteristic work function variations of grain
boundaries, standing-collapsed wrinkles, and folded wrinkles could
be clearly identified. Classical and quantum molecular dynamics simulations
reveal that the unique work function distribution of each type of
line defects is originated from the doping effect induced by the SiO<sub>2</sub> substrate. Our results suggest that KPFM can be an easy-to-use
and accurate method to detect graphene line defects, and also propose
the possibility to tune the graphene work function by defect engineering