7 research outputs found
Bioinspired Hierarchical Alumina–Graphene Oxide–Poly(vinyl alcohol) Artificial Nacre with Optimized Strength and Toughness
Due to hierarchical organization
of micro- and nanostructures, natural nacre exhibits extraordinary
strength and toughness, and thus provides a superior model for the
design and fabrication of high-performance artificial composite materials.
Although great progress has been made in constructing layered composites
by alternately stacking hard inorganic platelets and soft polymers,
the real issue is that the excellent strength of these composites
was obtained at the sacrifice of toughness. In this work, inspired
by the layered aragonite microplatelets/chitin nanofibers–protein
structure of natural nacre, alumina microplatelets–graphene
oxide nanosheets–polyÂ(vinyl alcohol) (Al<sub>2</sub>O<sub>3</sub>/GO–PVA) artificial nacre is successfully constructed through
layer-by-layer bottom-up assembly, in which Al<sub>2</sub>O<sub>3</sub> and GO–PVA act as “bricks” and “mortar”,
respectively. The artificial nacre has hierarchical “brick-and-mortar”
structure and exhibits excellent strength (143 ± 13 MPa) and
toughness (9.2 ± 2.7 MJ/m<sup>3</sup>), which are superior to
those of natural nacre (80–135 MPa, 1.8 MJ/m<sup>3</sup>).
It was demonstrated that the multiscale hierarchical structure of
ultrathin GO nanosheets and submicrometer-thick Al<sub>2</sub>O<sub>3</sub> platelets can deal with the conflict between strength and
toughness, thus leading to the excellent mechanical properties that
cannot be obtained using only one size of platelet. We strongly believe
that the work presented here provides a creative strategy for designing
and developing new composites with excellent strength and toughness
Three-Dimensional Crumpled Graphene-Based Nanosheets with Ultrahigh NO<sub>2</sub> Gas Sensibility
It is well-established that the structures
dominate the properties.
Inspired by the highly contorted and crumpled maxilloturbinate inside
dog nose, herein an artificial nanostructure, i.e., 3D crumpled graphene-based
nanosheets, is reported with the simple fabrication, detailed characterizations,
and efficient gas-sensing applications. A facile supramolecular noncovalent
assembly is introduced to modify graphene with functional molecules,
followed with a lyophilization process to massively transform 2D plane
graphene-based nanosheets to 3D crumpled structure. The detailed morphological
characterizations reveal that the bioinspired nanosheets exhibit full
consistency with maxilloturbinate. The fabricated 3D crumpled graphene-based
sensors exhibit ultrahigh response (<i>R</i><sub>a</sub>/R<sub>g</sub> = 3.8) toward 10 ppm of NO<sub>2</sub>, which is mainly
attributed to the specific maxilloturbinate-mimic structure. The sensors
also exhibit excellent selectivity and sensing linearity, reliable
repeatability, and stability. Interestingly, it is observed that only
4 mg of graphene oxide (GO) raw materials can produce more than 1000
gas sensors, which provides a new insight for developing novel 3D
biomimetic materials in large-scale gas sensor production
Tunable, Fast, Robust Hydrogel Actuators Based on Evaporation-Programmed Heterogeneous Structures
The ability to topographically structure
and fast controllably
actuate hydrogel in two and three dimensions is the key for their
promising applications in soft robots, microfluidic valves, cell and
drug delivery, and artificial muscles. Inspired by evaporation-induced
concentration differentiation phenomenon in the production process
of beancurd sheet, we introduce a facile one-step evaporation process
to create laminated layer/porous layer heterogeneous structure within
graphene oxide-clay-polyÂ(<i>N</i>-isopropylacrylamide) hydrogel
in vertical direction and pattern the heterogeneous structure in lateral
direction to form tunable, fast, and robust hydrogel actuators. The
laminated layer/porous layer architecture is highly stable and robust
without possibility of delamination. The evaporation-programmed heterogeneous
structures tune thermoresponsive actuations from global bending/unbending
for global heterogeneous structure to local bending/unbending and
site-specific folding/unfolding for segment-patterned heterogeneous
structure, then to directional bending/unbending and chiral twisting/untwisting
for stripe-patterned heterogeneous structure. These actuations are
instant and reversible without detectable fatigue after many cycles
Tunable, Fast, Robust Hydrogel Actuators Based on Evaporation-Programmed Heterogeneous Structures
The ability to topographically structure
and fast controllably
actuate hydrogel in two and three dimensions is the key for their
promising applications in soft robots, microfluidic valves, cell and
drug delivery, and artificial muscles. Inspired by evaporation-induced
concentration differentiation phenomenon in the production process
of beancurd sheet, we introduce a facile one-step evaporation process
to create laminated layer/porous layer heterogeneous structure within
graphene oxide-clay-polyÂ(<i>N</i>-isopropylacrylamide) hydrogel
in vertical direction and pattern the heterogeneous structure in lateral
direction to form tunable, fast, and robust hydrogel actuators. The
laminated layer/porous layer architecture is highly stable and robust
without possibility of delamination. The evaporation-programmed heterogeneous
structures tune thermoresponsive actuations from global bending/unbending
for global heterogeneous structure to local bending/unbending and
site-specific folding/unfolding for segment-patterned heterogeneous
structure, then to directional bending/unbending and chiral twisting/untwisting
for stripe-patterned heterogeneous structure. These actuations are
instant and reversible without detectable fatigue after many cycles
Table_1_Effects of tumor necrosis factor-alpha inhibitors on lipid profiles in patients with psoriasis: a systematic review and meta-analysis.docx
BackgroundThere is no consensus on the effect of tumor necrosis factor-alpha (TNF-alpha) inhibitors on lipid profiles in patients with psoriasis. This study aimed to investigate the effects of TNF-alpha inhibitors on lipid profiles (triglycerides, total cholesterol, low-density lipoprotein, or high-density lipoprotein) in patients with psoriasis. MethodsWe searched PubMed, Embase, and Cochrane Library databases for articles published before October 17, 2023. Four TNF-alpha inhibitors (infliximab, etanercept, adalimumab, and certolizumab) were included in our study. (PROSPERO ID: CRD42023469703).ResultsA total of twenty trials were included. Overall results revealed that TNF-alpha inhibitors elevated high-density lipoprotein levels in patients with psoriasis (WMD = 2.31; 95% CI: 0.96, 3.67; P = 0.001), which was supported by the results of sensitivity analyses excluding the effect of lipid-lowering drugs. Subgroup analyses indicated that high-density lipoprotein levels were significantly increased in the less than or equal to 3 months group (WMD = 2.88; 95% CI: 1.37, 4.4; P ConclusionOur results revealed that TNF-alpha inhibitors might temporarily increase high-density lipoprotein levels in patients with psoriasis. However, changes in triglycerides were not consistent among the different durations of treatment, with significant increases after 3 to 6 months of treatment. Future prospective trials with long-term follow-up contribute to confirming and extending our findings.Systematic Review Registrationhttps://www.crd.york.ac.uk/PROSPERO/, identifier CRD42023469703.</p
DataSheet_1_Effects of tumor necrosis factor-alpha inhibitors on lipid profiles in patients with psoriasis: a systematic review and meta-analysis.docx
BackgroundThere is no consensus on the effect of tumor necrosis factor-alpha (TNF-alpha) inhibitors on lipid profiles in patients with psoriasis. This study aimed to investigate the effects of TNF-alpha inhibitors on lipid profiles (triglycerides, total cholesterol, low-density lipoprotein, or high-density lipoprotein) in patients with psoriasis. MethodsWe searched PubMed, Embase, and Cochrane Library databases for articles published before October 17, 2023. Four TNF-alpha inhibitors (infliximab, etanercept, adalimumab, and certolizumab) were included in our study. (PROSPERO ID: CRD42023469703).ResultsA total of twenty trials were included. Overall results revealed that TNF-alpha inhibitors elevated high-density lipoprotein levels in patients with psoriasis (WMD = 2.31; 95% CI: 0.96, 3.67; P = 0.001), which was supported by the results of sensitivity analyses excluding the effect of lipid-lowering drugs. Subgroup analyses indicated that high-density lipoprotein levels were significantly increased in the less than or equal to 3 months group (WMD = 2.88; 95% CI: 1.37, 4.4; P ConclusionOur results revealed that TNF-alpha inhibitors might temporarily increase high-density lipoprotein levels in patients with psoriasis. However, changes in triglycerides were not consistent among the different durations of treatment, with significant increases after 3 to 6 months of treatment. Future prospective trials with long-term follow-up contribute to confirming and extending our findings.Systematic Review Registrationhttps://www.crd.york.ac.uk/PROSPERO/, identifier CRD42023469703.</p
Mimicking a Dog’s Nose: Scrolling Graphene Nanosheets
Inspired
by the densely covered capillary structure inside a dog’s
nose, we report an artificial nanostructure, <i>i</i>.<i>e</i>., polyÂ(sodium <i>p</i>-styrenesulfonate)-functionalized
reduced graphene oxide nanoscrolls (PGNS), with high structural perfection
and efficient gas sensing applications. A facile supramolecular assembly
is introduced to functionalize graphene with the functional polymer,
combined with the lyophilization technique to massively transform
the planar graphene-based nanosheets to nanoscrolls. Detailed characterizations
reveal that the bioinspired nanoscrolls exhibit a wide-open tubular
morphology with uniform dimensions that is structurally distinct from
the previously reported ones. The detailed morphologies of the graphene-based
nanosheets in each scrolling stage during lyophilization are monitored
by cryo-SEM. This unravels an asymmetric polymer-induced graphene
scrolling mechanism including the corresponding scrolling process,
which is directly presented by molecular dynamics simulations. The
fabricated PGNS sensors exhibit superior gas sensing performance with
reliable repeatability, excellent linear sensibility, and, especially,
an ultrahigh response (<i>R</i><sub>a</sub>/<i>R</i><sub>g</sub> = 5.39, 10 ppm) toward NO<sub>2</sub>. The supramolecular
assembly combined with the lyophilization technique to fabricate PGNS
provides a strategy to design biomimetic materials for gas sensors
and chemical trace detectors