For effective hydrogen production by water splitting, it is essential to develop earth‐abundant, highly efficient, and durable electrocatalysts. Herein, the authors report a bifunctional ...electrocatalyst composed of hollow CoSx and Ni–Fe based layered double hydroxide (NiFe LDH) nanosheets for efficient overall water splitting (OWS). The optimized heterostructure is obtained by the electrodeposition of NiFe LDH nanosheets on metal–organic framework‐derived hollow CoSx nanoarrays, which are supported on nickel foam (H‐CoSx@NiFe LDH/NF). The unique structure of the hybrid material not only provides ample active sites, but also facilitates electrolyte penetration and gas release during the reactions. Additionally, the strong coupling and synergy between the hydrogen evolution reaction (HER) active CoSx and the oxygen evolution reaction (OER) active NiFe LDH gives rise to the excellent bifunctional properties. Consequently, H‐CoSx@NiFe LDH/NF exhibits remarkable HER and OER activities with overpotentials of 95 and 250 mV, respectively at 10 mA cm−2 in 1.0 M KOH. Even at 1.0 A cm−2, the electrode requires small overpotentials of 375 mV (for HER) and 418 mV (for OER), respectively. An electrolyzer based on H‐CoSx@NiFe LDH/NF demonstrates a low cell voltage of 1.98 V at a current density of 300 mA cm−2 and good durability for 100 h in OWS application.
H‐CoSx@NiFe LDH bifunctional catalysts are prepared by electrodepositing NiFe LDH nanosheets onto hollow CoSx nanoarrays uniformly grown on nickel foam. The obtained heterostructures show remarkable activities of HER and OER, which are attributed to unique structures, facile electrolyte penetration, and efficient gas release during the reactions of the water‐splitting process.
Chondrogenesis is a highly coordinated event in embryo development, adult homeostasis, and repair of the vertebrate cartilage. Fate decisions and differentiation of chondrocytes accompany ...differential expression of genes critical for each step of chondrogenesis. SOX9 is a master transcription factor that participates in sequential events in chondrogenesis by regulating a series of downstream factors in a stage-specific manner. SOX9 either works alone or in combination with downstream SOX transcription factors, SOX5 and SOX6 as chondrogenic SOX Trio. SOX9 is reduced in the articular cartilage of patients with osteoarthritis while highly maintained during tumorigenesis of cartilage and bone. Gene therapy using viral and non-viral vectors accompanied by tissue engineering (scaffolds) is a promising tool to regenerate impaired cartilage. Delivery of SOX9 or chondrogenic SOX Trio into cells produces efficient therapeutic effects on chondrogenesis and this event is facilitated by scaffolds. Non-viral vector-guided delivery systems encapsulated or loaded in mechanically stable solid scaffolds are useful for the regeneration of articular cartilage. Here we review major milestones and most recent studies focusing on regulation and function of chondrogenic SOX Trio, during chondrogenesis and cartilage regeneration, and on the development of advanced technologies in gene delivery with tissue engineering to improve efficiency of cartilage repair process.
In this work, a facile salt‐templated approach is developed for the preparation of hollow FeSe2/graphitic carbon composite microspheres as sodium‐ion battery anodes; these are composed of ...interconnected multicavities and an enclosed surface in‐plane embedded with uniform hollow FeSe2 nanoparticles. As the precursor, Fe2O3/carbon microspheres containing NaCl nanocrystals are obtained using one‐pot ultrasonic spray pyrolysis in which inexpensive NaCl and dextrin are used as a porogen and carbon source, respectively, enabling mass production of the composites. During post‐treatment, Fe2O3 nanoparticles in the composites transform into hollow FeSe2 nanospheres via the Kirkendall effect. These rational structures provide numerous conductive channels to facilitate ion/electron transport and enhance the capacitive contribution. Moreover, the synergistic effect between the hollow cavities within FeSe2 and the outstanding mechanical strength of the porous carbon matrix can effectively accommodate the large volume changes during cycling. Correspondingly, the composite microsphere exhibits high discharge capacity of 510 mA h g−1 after 200 cycles at 0.2 A g−1 with capacity retention of 88% when calculated from the second cycle. Even at a high current density of 5.0 A g−1, a high discharge capacity of 417 mA h g−1 can be achieved.
Hollow FeSe2/graphitic carbon composite microspheres with interconnected multicavities are introduced as anodes for high‐performance sodium‐ion batteries. The synergistic effect between the hollow cavities within FeSe2 and the porous carbon matrix is responsible for superior performances of the composite microspheres for sodium‐ion batteries.
Protein-based conjugates are valuable constructs for a variety of applications. Conjugation of proteins to fluorophores is commonly used to study their cellular localization and the protein-protein ...interactions. Modification of therapeutic proteins with either polymers or cytotoxic moieties greatly enhances their pharmacokinetics or potency. To label a protein of interest, conventional direct chemical reaction with the side-chains of native amino acids often yields heterogeneously modified products. This renders their characterization complicated, requires difficult separation steps and may impact protein function. Although modification can also be achieved via the insertion of unnatural amino acids bearing bioorthogonal functional groups, these methods can have lower protein expression yields, limiting large scale production. As a site-specific modification method, enzymatic protein labelling is highly efficient and robust under mild reaction conditions. Significant progress has been made over the last five years in modifying proteins using enzymatic methods for numerous applications, including the creation of clinically relevant conjugates with polymers, cytotoxins or imaging agents, fluorescent or affinity probes to study complex protein interaction networks, and protein-linked materials for biosensing. This review summarizes developments in enzymatic protein labelling over the last five years for a panel of ten enzymes, including sortase A, subtiligase, microbial transglutaminase, farnesyltransferase, N-myristoyltransferase, phosphopantetheinyl transferases, tubulin tyrosin ligase, lipoic acid ligase, biotin ligase and formylglycine generating enzyme.
Despite their high theoretical specific capacity (1675 mA h g−1), the practical application of Li–S batteries remains limited because the capacity rapidly degrades through severe dissolution of ...lithium polysulfide and the rate capability is low because of the low electronic conductivity of sulfur. This paper describes novel hierarchical yolk–shell microspheres comprising 1D bamboo‐like N‐doped carbon nanotubes (CNTs) encapsulating Co nanoparticles (Co@BNCNTs YS microspheres) as efficient cathode hosts for Li–S batteries. The microspheres are produced via a two‐step process that involves generation of the microsphere followed by N‐doped CNTs growth. The hierarchical yolk–shell structure enables efficient sulfur loading and mitigates the dissolution of lithium polysulfides, and metallic Co and N doping improves the chemical affinity of the microspheres with sulfur species. Accordingly, a Co@BNCNTs YS microsphere‐based cathode containing 64 wt% sulfur exhibits a high discharge capacity of 700.2 mA h g−1 after 400 cycles at a current density of 1 C (based on the mass of sulfur); this corresponds to a good capacity retention of 76% and capacity fading rate of 0.06% per cycle with an excellent rate performance (752 mA h g−1 at 2.0 C) when applied as cathode hosts for Li–S batteries.
Hierarchical yolk–shell microspheres comprising 1D bamboo‐like N‐doped carbon nanotubes (CNTs) encapsulating Co nanocrystals are first introduced as efficient cathode hosts for Li–S batteries. The synergetic effect of the presence of the N‐doped CNTs with Co nanocrystals and the hierarchical structure of yolk‐shell microspheres is responsible for the superior performances as the cathode hosts for Li–S batteries.
Proliferating cancer cells rely largely on glutamine for survival and proliferation. Glutamine serves as a carbon source for the synthesis of lipids and metabolites via the TCA cycle, as well as a ...source of nitrogen for amino acid and nucleotide synthesis. To date, many studies have explored the role of glutamine metabolism in cancer, thereby providing a scientific rationale for targeting glutamine metabolism for cancer treatment. In this review, we summarize the mechanism(s) involved at each step of glutamine metabolism, from glutamine transporters to redox homeostasis, and highlight areas that can be exploited for clinical cancer treatment. Furthermore, we discuss the mechanisms underlying cancer cell resistance to agents that target glutamine metabolism, as well as strategies for overcoming these mechanisms. Finally, we discuss the effects of glutamine blockade on the tumor microenvironment and explore strategies to maximize the utility of glutamine blockers as a cancer treatment.
This study seeks to understand the impact of tourist experience of the metaverse on users' actual visit intentions by proposing an integration of the Technology Acceptance Model (TAM) and the Theory ...of Planned Behavior (TPB), using the construct of Presence. We developed a questionnaire‐based experiment in which 478 responses were collected via an online survey to achieve the objectives of the study. Structural equation modeling was used to test the relationships among the proposed constructs. The results indicate that presence is positively associated with perceived ease of use, perceived usefulness, and attitude, respectively. In addition to the relationship between perceived ease of use and attitude, six other hypotheses within the model that merged TAM and TPB were statistically supported. Furthermore, the implications and recommendations based on the results are valuable contributions to the development of metaverse tourism.
Uniquely structured CoSe2–carbon nanotube (CNT) composite microspheres with optimized morphology for the hydrogen‐evolution reaction (HER) are prepared by spray pyrolysis and subsequent selenization. ...The ultrafine CoSe2 nanocrystals uniformly decorate the entire macroporous CNT backbone in CoSe2–CNT composite microspheres. The macroporous CNT backbone strongly improves the electrocatalytic activity of CoSe2 by improving the electrical conductivity and minimizing the growth of CoSe2 nanocrystals during the synthesis process. In addition, the macroporous structure resulting from the CNT backbone improves the electrocatalytic activity of the CoSe2–CNT microspheres by increasing the removal rate of generated H2 and minimizing the polarization of the electrode during HER. The CoSe2–CNT composite microspheres demonstrate excellent catalytic activity for HER in an acidic medium (10 mA cm−2 at an overpotential of ≈174 mV). The bare CoSe2 powders exhibit moderate HER activity, with an overpotential of 226 mV at 10 mA cm−2. The Tafel slopes for the CoSe2–CNT composite and bare CoSe2 powders are 37.8 and 58.9 mV dec−1, respectively. The CoSe2–CNT composite microspheres have a slightly larger Tafel slope than that of commercial carbon‐supported platinum nanoparticles, which is 30.2 mV dec–1.
Macroporous CoSe2–carbon nanotube (CNT) composite microspheres demonstrating excellent electrocatalytic activity for hydrogen‐evolution reaction are prepared by a simple two‐step process based on spray pyrolysis. The macroporous CNT backbone strongly improves the electrocatalytic activity of CoSe2 by improving the electrical conductivity and minimizing the growth of CoSe2 nanocrystals. The Tafel slopes of the CoSe2–CNT composite is 37.8 mV dec–1.
During liver injury, hepatocytes secrete exosomes that include diverse types of self‐RNAs. Recently, self‐noncoding RNA has been recognized as an activator of Toll‐like receptor 3 (TLR3). However, ...the roles of hepatic exosomes and TLR3 in liver fibrosis are not yet fully understood. Following acute liver injury and early‐stage liver fibrosis induced by a single or 2‐week injection of carbon tetrachloride (CCl4), increased interleukin (IL)‐17A production was detected primarily in hepatic γδ T cells in wild‐type (WT) mice. However, liver fibrosis and IL‐17A production by γδ T cells were both significantly attenuated in TLR3 knockout (KO) mice compared with WT mice. More interestingly, IL‐17A‐producing γδ T cells were in close contact with activated hepatic stellate cells (HSCs), suggesting a role for HSCs in IL‐17A production by γδ T cells. In vitro treatments with exosomes derived from CCl4‐treated hepatocytes significantly increased the expression of IL‐17A, IL‐1β, and IL‐23 in WT HSCs but not in TLR3 KO HSCs. Furthermore, IL‐17A production by γδ T cells was substantially increased upon coculturing with exosome‐treated WT HSCs or conditioned medium from TLR3‐activated WT HSCs. However, similar increases were not detected when γδ T cells were cocultured with exosome‐treated HSCs from IL‐17A KO or TLR3 KO mice. Using reciprocal bone marrow transplantation between WT and TLR3 KO mice, we found that TLR3 deficiency in HSCs contributed to decreased IL‐17A production by γδ T cells, as well as liver fibrosis. Conclusion: In liver injury, the exosome‐mediated activation of TLR3 in HSCs exacerbates liver fibrosis by enhancing IL‐17A production by γδ T cells, which might be associated with HSC stimulation by unknown self‐TLR3 ligands from damaged hepatocytes. Therefore, TLR3 might be a novel therapeutic target for liver fibrosis. (Hepatology 2016;64:616‐631)
Highlights
A novel vacuum-assisted strategy is proposed to form N-doped carbon-encapsulated CoSe
2
nanocrystals within hollow mesoporous carbon nanospheres (CoSe
2
@NC/HMCS) via a solid-state ...reaction.
The “dual confinement” by both the N-doped carbon matrix derived from 2-methylimidazole and the small-sized pores of the hollow mesoporous carbon nanospheres can effectively prevent the overgrowth of CoSe
2
nanocrystals.
CoSe
2
@NC/HMCS exhibits an excellent electrochemical performance as the anode material for KIBs in terms of cycling stability and rate capability.
In this work, a novel vacuum-assisted strategy is proposed to homogenously form Metal–organic frameworks within hollow mesoporous carbon nanospheres (HMCSs) via a solid-state reaction. The method is applied to synthesize an ultrafine CoSe
2
nanocrystal@N-doped carbon matrix confined within HMCSs (denoted as CoSe
2
@NC/HMCS) for use as advanced anodes in high-performance potassium-ion batteries (KIBs). The approach involves a solvent-free thermal treatment to form a Co-based zeolitic imidazolate framework (ZIF-67) within the HMCS templates under vacuum conditions and the subsequent selenization. Thermal treatment under vacuum facilitates the infiltration of the cobalt precursor and organic linker into the HMCS and simultaneously transforms them into stable ZIF-67 particles without any solvents. During the subsequent selenization process, the “dual confinement system”, composed of both the N-doped carbon matrix derived from the organic linker and the small-sized pores of HMCS, can effectively suppress the overgrowth of CoSe
2
nanocrystals. Thus, the resulting uniquely structured composite exhibits a stable cycling performance (442 mAh g
−1
at 0.1 A g
−1
after 120 cycles) and excellent rate capability (263 mAh g
−1
at 2.0 A g
−1
) as the anode material for KIBs.
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