11 research outputs found
Additional file 1: of Lung tumor exosomes induce a pro-inflammatory phenotype in mesenchymal stem cells via NFÎşB-TLR signaling pathway
mRNA expression changes of IL-6, IL-8 and MCP-1 in MSCs stimulated with exosomes after knockdown of TLR2 by siRNA combinations for 24h. (TIF 236 kb
Genistein Ameliorates Non-alcoholic Fatty Liver Disease by Targeting the Thromboxane A<sub>2</sub> Pathway
Non-alcoholic fatty liver disease
(NAFLD) is now a public health issue worldwide, but no drug has yet
received approval. Genistein, an isoflavonoid derived from soybean,
ameliorates high-fat-diet-induced NAFLD in mice, but the molecular
underpinnings remain largely elusive. Arachidonic acid (AA) is a major
ingredient of animal fats, and the AA cascade has been implicated
in chronic inflammation. In this study, we investigated whether genistein
was against NAFLD by targeting the AA cascade. Using a mouse model,
we showed that genistein supplementation improved high-fat-diet-induced
NAFLD by normalizing hepatomegaly, liver steatosis, aminotransferase
abnormalities, and glucose tolerance. The thromboxane A<sub>2</sub> (TXA<sub>2</sub>) pathway was aberrantly active in NAFLD, evidenced
by an elevation of circulating TXA<sub>2</sub> and hepatic thromboxane
A<sub>2</sub> receptor expression. Mechanistically, we found that
genistein directly targeted cyclooxygenase-1 activity as well as its
downstream TXA<sub>2</sub> biosynthesis, while the TXA<sub>2</sub> pathway might mediate NAFLD progression by impairing insulin sensitivity.
Taken together, our study revealed a crucial pathophysiological role
of the TXA<sub>2</sub> pathway in NAFLD and provided an explanation
as to how genistein was against NAFLD progression
Genistein Ameliorates Non-alcoholic Fatty Liver Disease by Targeting the Thromboxane A<sub>2</sub> Pathway
Non-alcoholic fatty liver disease
(NAFLD) is now a public health issue worldwide, but no drug has yet
received approval. Genistein, an isoflavonoid derived from soybean,
ameliorates high-fat-diet-induced NAFLD in mice, but the molecular
underpinnings remain largely elusive. Arachidonic acid (AA) is a major
ingredient of animal fats, and the AA cascade has been implicated
in chronic inflammation. In this study, we investigated whether genistein
was against NAFLD by targeting the AA cascade. Using a mouse model,
we showed that genistein supplementation improved high-fat-diet-induced
NAFLD by normalizing hepatomegaly, liver steatosis, aminotransferase
abnormalities, and glucose tolerance. The thromboxane A<sub>2</sub> (TXA<sub>2</sub>) pathway was aberrantly active in NAFLD, evidenced
by an elevation of circulating TXA<sub>2</sub> and hepatic thromboxane
A<sub>2</sub> receptor expression. Mechanistically, we found that
genistein directly targeted cyclooxygenase-1 activity as well as its
downstream TXA<sub>2</sub> biosynthesis, while the TXA<sub>2</sub> pathway might mediate NAFLD progression by impairing insulin sensitivity.
Taken together, our study revealed a crucial pathophysiological role
of the TXA<sub>2</sub> pathway in NAFLD and provided an explanation
as to how genistein was against NAFLD progression
Orderly Aggregated Catalytic Hairpin Assembly for Synchronous Ultrasensitive Detecting and High-Efficiency Co-Localization Imaging of Dual-miRNAs in Living Cells
In this work, the orderly aggregated catalytic hairpin
assembly
(OA-CHA) was developed for synchronous ultrasensitive detection and
high-efficiency colocalization imaging of dual-miRNAs by a carefully
designed tetrahedral conjugated ladder DNA structure (TCLDS). Exactly,
two diverse hairpin probes were fixed on tetrahedron conjugated DNA
nanowires to form the TCLDS without fluorescence response, which triggered
OA-CHA in the aid of output DNA 1 and output DNA 2 produced by targets
miRNA-217 and miRNA-196a cycle to generate TCLDS with remarkable fluorescence
response. Impressively, compared with the traditional CHA strategy,
OA-CHA avoided the fluorescence group and quenching group from approaching
again because of the spatial confinement effect to significantly enhance
the fluorescence signal, resulting in the simultaneous ultrasensitive
detection of dual-miRNAs with detection limits of 21 and 32 fM for
miRNA-217 and miRNA-196a, respectively. Meanwhile, the TCLDS with
lower diffusivity could achieve accurate localization imaging for
reflecting the spatial distribution of dual-miRNAs in living cells.
The strategy based on OA-CHA provided a flexible and programmable
nucleic amplification method for the synchronous ultrasensitive detection
and precise imaging of multiple biomarkers and had potential in disease
diagnostics.
Scalable Production of Few-Layer Boron Sheets by Liquid-Phase Exfoliation and Their Superior Supercapacitive Performance
Although two-dimensional
boron (B) has attracted much attention
in electronics and optoelectronics due to its unique physical and
chemical properties, in-depth investigations and applications have
been limited by the current synthesis techniques. Herein, we demonstrate
that high-quality few-layer B sheets can be prepared in large quantities
by sonication-assisted liquid-phase exfoliation. By simply varying
the exfoliating solvent types and centrifugation speeds, the lateral
size and thickness of the exfoliated B sheets can be controllably
tuned. Additionally, the exfoliated few-layer B sheets exhibit excellent
stability and outstanding dispersion in organic solvents without aggregates
for more than 50 days under ambient conditions, owing to the presence
of a solvent residue shell on the B sheet surface that provides excellent
protection against air oxidation. Moreover, we also demonstrate the
use of the exfoliated few-layer B sheets for high-performance supercapacitor
electrode materials. This as-prepared device exhibits impressive electrochemical
performance with a wide potential window of up to 3.0 V, excellent
energy density as high as 46.1 Wh/kg at a power density of 478.5 W/kg,
and excellent cycling stability with 88.7% retention of the initial
specific capacitance after 6000 cycles. This current work not only
demonstrates an effective strategy for the synthesis of the few-layer
B sheets in a controlled manner but also makes the resulting materials
promising for next-generation optoelectronics and energy storage applications
Facile Synthesis of Millimeter-Scale Vertically Aligned Boron Nitride Nanotube Forests by Template-Assisted Chemical Vapor Deposition
There
is an increasing amount of research interest in synthesizing
boron nitride nanotubes (BNNTs) as well as BN coatings to be used
for various applications due to their outstanding mechanical, electrical,
and thermal properties. However, vertically aligned (VA) BNNTs are
difficult to synthesize and the longest VA-BNNTs achieved to date
are up to several tens of microns. Here, we report the synthesis of
over millimeters long multiwalled BN coated carbon nanotubes (BN/CNT)
and BNNT forests via a facile and effective two-step route involving
template-assisted chemical vapor deposition at a relatively low temperature
of 900 °C and a subsequent annealing process. The as-prepared
BN/CNTs and BNNTs retain the highly ordered vertically aligned structures
of the CNT templates as identified by scanning electron microscopy.
The structure and composition of the resulting products were studied
using transmission electron microscopy, electron energy-loss spectroscopy,
X-ray photoelectron spectroscopy, Raman spectroscopy, Fourier transform
infrared spectroscopy, and thermogravimetric analysis. This versatile
BN coating technique and the synthesis of millimeter-scale BN/CNTs
and BNNTs pave the way for new applications especially where the aligned
geometry of the NTs is essential such as for field-emission, interconnects,
and thermal management
Supercompressible Coaxial Carbon Nanotube@Graphene Arrays with Invariant Viscoelasticity over −100 to 500 °C in Ambient Air
Vertically
aligned carbon nanotube (CNT) arrays have been recognized
as promising cushion materials because of their superior thermal stability,
remarkable compressibility, and viscoelastic characteristics. However,
most of the previously reported CNT arrays still suffer from permanent
shape deformation at only moderate compressive strains, which considerably
restricts their practical applications. Here, we demonstrate a facile
strategy of fabricating supercompressible coaxial CNT@graphene (CNT@Gr)
arrays by using a two-step route involving encapsulating polymer layers
onto plastic CNT arrays and subsequent annealing processes. Notably,
the resulting CNT@Gr arrays are able to almost completely recover
from compression at a strain of up to 80% and retain ∼80% recovery
even after 1000 compression cycles at a 60% strain, demonstrating
their excellent compressibility. Furthermore, they possess outstanding
strain- and frequency-dependent viscoelastic responses, with storage
modulus and damping ratio of up to ∼6.5 MPa and ∼0.19,
respectively, which are nearly constant over an exceptionally broad
temperature range of −100 to 500 °C in ambient air. These
supercompressibility and temperature-invariant viscoelasticity together
with facile fabrication process of the CNT@Gr arrays enable their
promising multifunctional applications such as energy absorbers, mechanical
sensors, and heat exchangers, even in extreme environments
Trimethylamine Borane: A New Single-Source Precursor for Monolayer h‑BN Single Crystals and h‑BCN Thin Films
Due to their exceptional chemical
and thermal stabilities as well
as electrically insulating property, atomically thin hexagonal boron
nitride (h-BN) films have been identified as a promising class of
dielectric substrate and encapsulation material for high-performance
two-dimensional (2D) heterostructure devices. Herein, we report a
facile chemical vapor deposition synthesis of large-area atomically
thin h-BN including monolayer single crystals and C-doped h-BN (h-BCN)
films utilizing a relatively low-cost, commercially available trimethylamine
borane (TMAB) as a single-source precursor. Importantly, pristine
2D h-BN films with a wide band gap of ∼6.1 eV can be achieved
by limiting the sublimation temperature of TMAB at 40 °C, while
C dopants are introduced to the h-BN films when the sublimation temperature
is further increased. The h-BCN thin films displayed band gap narrowing
effects as identified by an additional shoulder at 205 nm observed
in their absorbance spectra. Presence of N–C bonds in the h-BCN
structures with a doping concentration of ∼2 to 5% is confirmed
by X-ray photoelectron spectroscopy. The inclusion of low C doping
in the h-BN films is expected to result in constructive enhancement
to its mechanical properties without significant alteration to its
electrically insulating nature. This study provides new insights into
the design and fabrication of large-area atomically thin h-BN/h-BCN
films toward practical applications and suggests that the range of
precursors can be potentially extended to other anime borane complexes
as well
Biocompatible Hydroxylated Boron Nitride Nanosheets/Poly(vinyl alcohol) Interpenetrating Hydrogels with Enhanced Mechanical and Thermal Responses
Poly(vinyl alcohol)
(PVA) hydrogels with tissue-like viscoelasticity,
excellent biocompatibility, and high hydrophilicity have been considered
as promising cartilage replacement materials. However, lack of sufficient
mechanical properties is a critical barrier to their use as load-bearing
cartilage substitutes. Herein, we report hydroxylated boron nitride
nanosheets (OH-BNNS)/PVA interpenetrating hydrogels by cyclically
freezing/thawing the aqueous mixture of PVA and highly hydrophilic
OH-BNNS (up to 0.6 mg/mL, two times the highest reported so far).
Encouragingly, the resulting OH-BNNS/PVA hydrogels exhibit controllable
reinforcements in both mechanical and thermal responses by simply
varying the OH-BNNS contents. Impressive 45, 43, and 63% increases
in compressive, tensile strengths and Young’s modulus, respectively,
can be obtained even with only 0.12 wt% (OH-BNNS:PVA) OH-BNNS addition.
Meanwhile, exciting improvements in the thermal diffusivity (15%)
and conductivity (5%) can also be successfully achieved. These enhancements
are attributed to the synergistic effect of intrinsic superior properties
of the as-prepared OH-BNNS and strong hydrogen bonding interactions
between the OH-BNNS and PVA chains. In addition, excellent cytocompatibility
of the composite hydrogels was verified by cell proliferation and
live/dead viability assays. These biocompatible OH-BNNS/PVA hydrogels
are promising in addressing the mechanical failure and locally overheating
issues as cartilage substitutes and may also have broad utility for
biomedical applications, such as drug delivery, tissue engineering,
biosensors, and actuators
Concentric and Spiral Few-Layer Graphene: Growth Driven by Interfacial Nucleation vs Screw Dislocation
Spiral growth of various nanomaterials including some two-dimensional (2D) transition metal dichalcogenides had recently been experimentally realized using chemical vapor deposition (CVD). However, such growth that is driven by screw dislocation remained elusive for graphene and is rarely discussed because of the use of metal catalysts. In this work, we show that formation of few-layer graphene (FLG) with a spiral structure driven by screw dislocation can be obtained alongside FLG having a concentric layered structure formed by interfacial nucleation (nucleation at the graphene/Cu interface) using Cu-catalyzed ambient pressure CVD. Unlike commonly reported FLG grown by interfacial nucleation where the second layer is grown independently beneath the first, the growth of a spiral structure adopts a top growth mechanism where the top layers are an extension from the initial monolayer which spirals around an axial dislocation in self-perpetuating steps. Since the same atomic orientation is preserved, the subsequent spiraling layers are stacked in an oriented AB-stacked configuration. This contrasts with FLG formed by interfacial nucleation where turbostratic stacking of the entire adlayer may exist. In both growth scenarios, the second layer (either top or bottom) can grow across the grain boundaries of the initial monolayer domains, forming partial regions with turbostratic stacking configuration due to weak interlayer van der Waals interactions. The unique interlayer coupling of FLG spirals, which enable superior conductivity along the normal of the 2D crystal with spiraling trajectories, are expected to have new and interesting nanoscale applications