Search

Developing efficient, low-cost and bifunctional catalysts with predominant durability for the hydrogen evolution reaction (HER) and the oxygen evolution reaction (OER) is an extraordinary challenge in the preparation of green hydrogen energy by electrochemical water splitting. Three-dimensional (3D) transition metal compounds have become a research hotspot as OER electrocatalysts, which can replace noble metal oxides such as RuO 2 and IrO 2 to reduce application costs. Herein, we synthesized a novel three-dimensional pine-tree-like bimetallic sulfide arrays on nickel foam (FeCoS/NF) using various optimization strategies such as morphology optimization, in situ growth and introduction of heterogeneous structures. The as-synthesized FeCoS/NF electrocatalyst only requires relatively low overpotential of 156 mV to achieve a current density of 20 mA cm−2 for OER, with a Tafel slope of only 37 mV dec−1. It also has a small charge transfer resistance, an electrochemical surface area and good electrochemical stability in alkaline electrolytes. The excellent performance of FeCoS/NF can be attributed to the synergistic effect and amorphous phase of FeCoS as well as the well-defined pine-tree-like array architecture with a large surface area, abundant active sites, and sufficient gas and electrolyte diffusion channels. [Display omitted] • A 3D pine-tree-like structure of FeCoS/NF electrocatalyst was synthesized. • The FeCoS/NF exhibits excellent electrocatalytic activity for OER. • FeCoS/NF-based zinc-air battery shows an open-circuit voltage of 1.27 V. [ABSTRACT FROM AUTHOR]

The design of low-cost, short time, mass preparation and high-efficiency of electrocatalysts for hydrogen evolution reaction (HER), oxygen evolution reaction (OER) and zinc air batteries are highly challenging. Herein, we design a bifunctional chrysanthemum-like electrocatalysts (Cu(OH) 2 @CoMoO 4 ·0.9H 2 O/CF) for highly efficient electrochemical water splitting by a simple and highly controllable two-step method in a few hours. This unique hierarchical electrocatalyst has porous structure and short diffusion paths, which can promote charge transfer, ion and water diffusion, and rapidly release hydrogen and oxygen bubbles. The obtained Cu(OH) 2 @CoMoO 4 ·0.9H 2 O/CF composite exhibits low overpotentials of 57 mV at −10 mA cm−2 toward the HER, which is superior to most of the previously reported CoMoO 4 -based electrocatalysts. And the Cu(OH) 2 @CoMoO 4 ·0.9H 2 O/CF exhibits excellent performance of 355 mV at 100 mA cm−2 toward the OER. Benefiting from the unique hierarchical heterostructure and the coupling effect between the inner and outer layers, the Cu(OH) 2 @CoMoO 4 ·0.9H 2 O/CF catalysts were endowed with high activity for water splitting. [Display omitted] [ABSTRACT FROM AUTHOR]

Alzheimer's disease (AD) is the most common neurodegenerative disease with limited therapeutic strategies. Cell cycle checkpoint protein kinase 1 (Chk1) is a Ser/Thr protein kinase which is activated in response to DNA damage, the latter which is an early event in AD. However, whether DNA damage-induced Chk1 activation participates in the development of AD and Chk1 inhibition ameliorates AD-like pathogenesis remain unclarified. Here, we demonstrate that Chk1 activity and the levels of protein phosphatase 2A (PP2A) inhibitory protein CIP2A are elevated in AD human brains, APP/PS1 transgenic mice, and primary neurons with Aβ treatment. Chk1 overexpression induces CIP2A upregulation, PP2A inhibition, tau and APP hyperphosphorylation, synaptic impairments, and cognitive memory deficit in mice. Moreover, Chk1 inhibitor (GDC0575) effectively increases PP2A activity, decreases tau phosphorylation, and inhibits Aβ overproduction in AD cell models. GDC0575 also reverses AD-like cognitive deficits and prevents neuron loss and synaptic impairments in APP/PS1 mice. In conclusion, our study uncovers a mechanism by which DNA damage-induced Chk1 activation promotes CIP2A-mediated tau and APP hyperphosphorylation and cognitive dysfunction in Alzheimer's disease and highlights the therapeutic potential of Chk1 inhibitors in AD. [ABSTRACT FROM AUTHOR]

Phenol is highly toxic and can cause damage to humans and the ecosystem even at low concentrations. Therefore, developing a rapid, sensitive and easy operated detection strategy still faces challenge. In this work, the covalent organic frameworks (COFs)-reinforced peroxidase-mimicking hybrid nanozyme was rationally designed by assembly COFs on magnetic Fe 3 O 4 @ZIF-8 nanozyme. The Fe 3 O 4 @ZIF-8 @COF hybrid nanozyme exhibited significant improved catalytic activity and can be developed as a rapid and sensitive phenol colorimetric sensor with ease operation. The core-shell structure and the crystallinity of the as-prepared hybrid nanozyme were characterized in detail by various analytical methods SEM, TEM, FT-IR, XRD and elemental mapping. The catalytic activity of Fe 3 O 4 @ZIF-8 @COF mimic enzyme was investigated in the presence of H 2 O 2 using 4-aminoantipyrine (4-AAP) as the substrate. The developed Fe 3 O 4 @ZIF-8 @COF hybrid nanozyme was applied to construct colorimetric sensor for phenol detection and the result presented high selectivity, excellent stability and good reusability with a wide linear range (6–350 μM), low detection limit (2 μM) and an advantageous response time (5 min). The designed catalyst makes the enhancement of peroxidase-like activity, which can be attributed to the unique core-shell structure with the inner catalytic site and the outer protection and enrichment COF shell. Therefore, this proposed colorimetric sensor with robust, stable and easy-recycled properties displayed excellent practical significance for the fast and sensitive detection of phenol in water environment. [Display omitted] • Magnetic core-shell MOFs@COFs hybrid nanozyme with ordered porosity was designed. • The inner monodisperse magnetic MOFs core provided peroxidase-like catalytic site. • Crystalline COFs with enhancement and protective function enhanced the mimic activity. • The MOFs@COFs colorimetric sensor enables rapid visual detection of phenol in 5 min [ABSTRACT FROM AUTHOR]

• A peroxidase-like artificial enzyme with elevated catalysis capacity has been achieved. • The down-sized Fe 3 O 4 nanoparticles were dispersed throughout the urchin-like MnO 2 burrs. • The defect in structure as well as the synergistic effect would allow extra enzyme ability. • The limit of detection for glucose was estimated to be 0.75 μmol L−1. In order to lower the limit of detection of glucose, a peroxidase-like artificial enzyme with elevated catalysis capacity has been achieved. Fe 3 O 4 -doped MnO 2 microspheres were fabricated through a two-step hydrothermal method for this purpose. TEM revealed that down-sized Fe 3 O 4 nanoparticles were dispersed throughout the urchin-like MnO 2 burrs. An additional XRD peak beyond Fe 3 O 4 and MnO 2 nanoparticles was observed, indicating a dislocation structure was formed. The defect in structure as well as the synergistic effect would allow extra enzyme ability. Based on the steady-state kinetic analyses and Michaelis–Menten model, the Michaelis–Menten constants (K m and v max) were figured out. The results showed that the Fe 3 O 4 –MnO 2 composite has elevated affinity toward the substrate TMB and H 2 O 2. The limit of detection for glucose was estimated to be 0.75 μmol L−1 based on the Fe 3 O 4 –MnO 2 composite artificial enzyme. The superparamagnetic properties endowed the material easy separation. The composite of this structure will provide a highly sensitive candidate method for accurate detection of glucose. [ABSTRACT FROM AUTHOR]

• Composite of CePO 4 with Ni as a HER catalyst is reported. • CePO 4 lead to enhanced electrical conductivity and H 2 desorption ability. • Ni/CePO 4 shows excellent electrocatalytic HER performance at high current density. • Mechanism of photocatalytic HER over CePO 4 -Ni with Eosin Y photosensitizer and electrocatalytic HER are proposed. Developing suitable electrocatalyst/photocatalyst cocatalyst with electron transfer and desorption of hydrogen active sites is extremely significance for hydrogen evolution reaction (HER). Herein, we develop a series of Ni/(m)CePO 4 catalyst with rich interfaces via thermal treatment at low temperature with Ni-BTC/CePO 4 as precursor. The as-synthesized Ni/(m)CePO 4 heterojunction possess compact heterogeneous interface, and large specific surface area by loading Ni nanosphere on CePO 4 nanowire. By carefully designing method, the powerfully intimated heterointerface between Ni and CePO 4 conducive to the conversion of adsorption energy toward H atoms and electron conductivity, which enhance the synergic effect for electro-/photo-catalytic HER performances. Impressively, the Ni/0.1CePO 4 catalyst renders outstanding electrocatalytic HER activity with an lowest overpotential of −120 mV at −10 mA cm−2 and a optimal Tafel slope of 72 mV dec−1. The overpotential of Ni/0.1CePO 4 catalyst is −288 mV at −100 mA cm−2, close to 20 wt% Pt/C. With Eosin Y as photosensitizer, the photocatalytic performance for H 2 generation speed is around 64 umol h−1. Additionally, the Ni/0.1CePO 4 catalyst exhibits wonderful cycle stability in both electro-/photo-catalytic HER. The possible speculation of mechanisms of HER have also been proposed. This work provides a new insight into design HER catalysts for electro-/photo-catalytic hydrogen evolution reaction. [ABSTRACT FROM AUTHOR]

Highlights: [•] The monodisperse magnetic polystyrene microbeads were chosen as the base of support. [•] The magnetic microbeads is of dispersion and abundant functional groups. [•] Functionalizable and metal-chelate surfaces for reversible enzyme immobilization. [•] The regenerated biocatalyst still reserved its original performance. [ABSTRACT FROM AUTHOR]

Countering the problem of expediting the peroxymonosulfate oxidation, porous carbon nanofibers loaded with copper-cobalt bimetallic particles (CuCo@ CNF) were synthesized by a three-step process, including electrospinning, solvothermal reaction and carbonization. The well-crystallized copper-cobalt nanoparticles with an average particle size of 322 nm, which were evenly decorated on the surface of the porous carbon nanofibers with a relatively high specific surface area (average value=161.281 m2 g−1), as examined by XRD, SEM, TEM, and BET. The saturation magnetization of CuCo@CNF measured by VSM is 26.5 emu g−1, suggesting its easy separation due to magnetic property. In CuCo@CNF-PMS system, the removal rate of Acid Red 1 (AR1) as a model pollutant can achieved 99.0% and 98.1% in the 1st and 7th run, respectively. Metal leaching after reaction were reduced for CuCo@CNF when compared with the respective CNF supported Co or Cu catalysts. In addition, the catalytic degradation mechanism of AR1 was elucidated by detecting reactive oxygen species (ROS: SO• 4 -, •OH and 1O 2) alongside the reaction. AR1 can even be mineralized through CuCo@CNF-PMS, evidenced by TOC removal rate of 55.5% within 20 min. These results suggest that the as-synthesized catalyst is an attractive candidate for the treatment of wastewater with recalcitrant organic pollutants. [Display omitted] • CuCo@CNF was synthesized by a three-step process, including electrospinning, solvothermal reaction and carbonization. • CuCo bimetallic nanoparticles with heterostructure was almost uniformly embedded in CNF. • Magnetic CuCo@CNF possesses mesoporous structure. • Reduced metal leaching and improved catalytic performance for PMS activation was achieved on CuCo@CNF. [ABSTRACT FROM AUTHOR]

Investigates the association between abnormal phosphorylation sites found in Alzheimer disease and the inhibition of its biological activity. Techniques used to prepare and phosphorylate human recombinant; Effect of different kinases on microtubule binding activity; Inhibition of microtubule binding activity.

Designing ultrahigh energy density and mass-loading of electrocatalysts for hydrogen evolution is highly desirable but remains a great challenge. Herein, a 3D high-rise architectural structure consisting of dense Ni(OH) 2 nanoparticles on CuMoO 4 nanocube heterostructure arrays on Ni foam (Ni(OH) 2 /CuMoO 4 /NF) is developed via a hydrothermal reaction, calcination and electrodeposition method. Benefitting from the optimized electronic configuration, hierarchical high-rise architecture, and large specific surface area and mesoporous, the Ni(OH) 2 /CuMoO 4 /NF exhibits superior hydrogen evolution reaction (HER) activity in 1.0 M KOH solution. Ni(OH) 2 /CuMoO 4 /NF only requires low overpotential of 70 mV achieving a current density of 10 mA cm−2 with a low Tafel slope of 80 mV dec−1, and superior long-term stability toward HER. This work provides a new structural design to high-rise architectural structures for efficient catalytic application. [Display omitted] • A highly topological nickel hydroxide doped copper molybdate oxide composite was synthesized. • The high-topology structure with a heterogeneous interface enhances the conductivity. • The typical structure and proper components contribute to the electrochemical activity. [ABSTRACT FROM AUTHOR]

4,4′-Spirobi[pentacyclo[5.4.0.0 2,6 .0 3,10 .0 5,9 ]undecane] ( 10 ) is first successfully prepared by a nine step synthetic scheme starting from the key intermediate (cyclopentadiene derivate, 2 ). This synthetic scheme avoids using the hardly obtainable spiro[4.4]nonatetraene ( 18 ) as the starting material. In the structure of 10 , two polycyclic cages share one spiro-carbon so that it has high density (1.2663 g/cm 3 ) and high volumetric heat of combustion (53.353 MJ/L). [ABSTRACT FROM AUTHOR]

• The alternation of AD-like pathology is similar in two STZ mouse models. • The deficits of insulin signaling occur in both of STZ mouse models. • Rapamycin reverses AD-like pathology in two STZ mouse models. • Rapamycin improves AKT/AMPK/p70s6/GSK-3β signal pathway. Alzheimer's disease (AD) and type 2 diabetes mellitus (T2DM) share some pathological features, including tau hyperphosphorylation and deficits in insulin signaling, but the underlying mechanism and effective drugs for treating AD are unknown. The AD-like brain impairments are almost same in both of mouse type 2 DM models induced by the multiple low-dose intraperitoneal (i.p.) streptozotocin (STZ) injection and twice intracerebroventricular (i.c.v.) STZ injection. We found that memory disorders, impairment of insulin signaling, and AD-like tauopathies were exhibited in two different STZ-induced mouse models and that the level of Advanced Glycation End Products (AGEs) was increased in two STZ mouse models. Inhibition of mTORC1 with rapamycin reversed the deficits of insulin signaling associated kinases activity, decreased levels of AGEs and AD-like tau phosphorylation, and also improved memory deficit in both STZ mice. Rapamycin attenuated HG-induced tau hyperphosphorylation via the AKT/AMPK/GSK-3β pathways and p70S6K in SH-SY5Y cells. Taken together, these data demonstrated that rapamycin improved STZ-induced AD-like tauopathies and memory deficit in mice via improving p70S6K and AKT/AMPK/GSK-3β signaling and decreasing AGEs. Therefore, regulating insulin signaling via mTORC1 is a new strategy for preventing T2DM-associated AD, and mTORC1 is a potential drug target. [ABSTRACT FROM AUTHOR]

The novel photocatalytic advanced oxidation catalyst, ZIF-67@MXene-TA-CNF (ZIF-67@MTC) aerogels, was prepared via introducing tannic acid-coated cellulose nanofibril (TA-CNF), two-dimensional layered MXene, and ZIF-67 into a composite aerogel network. Specially, TA assisted the crosslinking of CNF through hydrogen bonds to construct the flexible aerogel skeleton, accompanied by assembly of MXene and ZIF-67. MXene not only provided sufficient attachment sites for the anchoring of ZIF-67, but also can be used as a repository for electron transfer to facilitate the separation of photogenerated electrons and holes. In the peroxymonosulfate (PMS)/aerogels/visible light system, the SO 4 -, OH and 1O 2 were generated, and 1O 2 was the main reactive species. As a result, 99.9 % of Tetrabromobisphenol A (TBBPA) can be degraded and the total organic carbon (TOC) removal efficiency reached 81.8 % within 40 min in this system. The results might provide a new concept for the design of biomass aerogels for applications in organic pollutant removal. The ZIF-67/MXene/CNF aerogels could efficiently photocatalytic TBBPA degradation via peroxymonosulfate activation. [Display omitted] [ABSTRACT FROM AUTHOR]

A new bi-cage hydrocarbon, 4,4′-bipentacyclo[5.4.0.0 2,6 .0 3,10 .0 5,9 ]undecane ( 12 ) was designed based on a strategy to construct two cages simultaneously from one key molecule scaffold. Thus 12 was conveniently synthesized from 5,5′-bi(cyclopentadiene) ( 9 ) through a three steps synthetic route in 23% overall yield. The new bi-cage hydrocarbon has high density (1.2322 g/cm 3 ) and high volumetric heat of combustion (51.670 MJ/L). [ABSTRACT FROM AUTHOR]

Smart nanomaterials that can simultaneously detect and eliminate contaminants in water environment are significant for health protection. To achieve such goal, Co-MOF-74 was in-situ assembled on regenerated cellulose membranes followed by calcination process, thus achieving dual-functional Co 3 O 4 /cellulose derivative membrane (Co 3 O 4 /CDM) catalyst. The Co 3 O 4 morphology was readily controlled by further recrystallization of the deposited MOF precursor. Combining the high enrichment ability of cellulose membrane and outstanding peroxidase-active of Co 3 O 4 , the fast color reaction for phenol was accomplished within 10 min by Co 3 O 4 /CDM with the assistance of H 2 O 2 and 4-aminoantipyrine (4-AAP). Moreover, the Co 3 O 4 /CDM also portrayed an excellent degradation property for phenol elimination via sulfate radical-advanced oxidation processes (SR-AOPs). The degradation efficiency of phenol reached 93% in 20 min, and the possible mineralization mechanism was proposed based on the XPS and LC-MS analysis. Thus, Co-MOF-74 derived Co 3 O 4 /CDM shows excellent properties in aiding the colorimetric detection and degradation of phenol in aqueous solutions. [Display omitted] • In situ synthesis of Co-MOF-74 based Co 3 O 4 /cellulose derivative membrane (Co 3 O 4 /CDM) • Cellulose regenerated membrane can serve as a support for anchoring of Co-MOF-74 NPs. • Hydrothermal recrystallization approach can facilitate well distributed nanoparticles on membrane. • The recyclable Co 3 O 4 /CDM as enzyme mimics also showed high PMS activation property. • As-prepared Co 3 O 4 /CDM with dual-functional can enrich, detect and degrade phenol. [ABSTRACT FROM AUTHOR]

Abstract: Huntington''s disease (HD) is an autosomal dominant inheritable neurodegenerative disorder caused by expansion of a polyglutamine repeat in the amino-terminal region of huntingtin. Polyglutamine expansion causes mutant huntingtin to aggregate and accumulate in the nuclei and cytoplasm of neurons. The aggregated amino-terminal fragments of mutant huntingtin are toxic to neuronal cells and may be involved in the neurodegeneration in HD patient brains. Although nuclear mutant huntingtin has been found to affect gene expression, the effect of cytoplasmic mutant huntingtin remains to be investigated. We established stably transfected mouse neuroblastoma (N2a) cells that express soluble amino-terminal fragments of huntingtin containing 20 (20Q) or 150 (150Q) glutamine repeats. In these stable cell lines, both 20Q and 150Q are diffusely distributed in the cytoplasm without aggregate formation. However, the stable 150Q cells are deficient in neurite outgrowth. Compared with wild-type N2a cells and cells stably expressing 20Q, stable 150Q cells also have decreased viability and are more susceptible to apoptotic stimulation. These findings suggest that the cytoplasmic soluble mutant huntingtin is also toxic to cells. [Copyright &y& Elsevier]