Evidence for chromium crosses blood brain barrier from the hypothalamus in chromium mice model.

It has been shown that exposure to hexavalent Chromium, Cr (Ⅵ), via nasal cavity can have neurotoxicological effects and induces behavioral impairment due to the fact that blood brain barrier (BBB) does not cover olfactory bulb. But whether Cr (Ⅵ) can cross the BBB and have a toxicological effects in central nervous system (CNS) remains unclear. Therefore, we investigated the effects of Cr (Ⅵ) on mice treated with different concentrations and exposure time (14 days and 28 days) of Cr (Ⅵ) via intraperitoneal injection. Results revealed that Cr accumulated in hypothalamus (HY) in a timely dependent manner. Much more severer neuropathologies was observed in the group of mice exposed to Cr (Ⅵ) for 28 days than that for 14 days. Gliosis, neuronal morphological abnormalities, synaptic degeneration, BBB disruption and neuronal number loss were observed in HY. In terms of mechanism, the Nrf2 related antioxidant stress signaling dysfunction and activated NF-κB related inflammatory pathway were observed in HY of Cr (Ⅵ) intoxication mice. And these neuropathologies and signaling defects appeared in a timely dependent manner. Taking together, we proved that Cr (Ⅵ) can enter HY due to weaker BBB in HY and HY is the most vulnerable CNS region to Cr (Ⅵ) exposure. The concentration of Cr in HY increased along with time. The accumulated Cr in HY can cause BBB disruption, neuronal morphological abnormalities, synaptic degeneration and gliosis through Nrf2 and NF-κB signaling pathway. This finding improves our understanding of the neurological dysfunctions observed in individuals who have occupational exposure to Cr (Ⅵ), and provided potential therapeutic targets to treat neurotoxicological pathologies induced by Cr (Ⅵ).

Seafood waste derived Pt/Chitin nanocatalyst for efficient hydrogenation of nitroaromatic compounds.

The fabrication of reliable, reusable and efficient catalyst is crucial for the conversion of nitroaromatic compounds into more chemically valuable amine-based molecules. In this study, a series of chitin supported platinum (Pt) catalysts with high catalytic activity, stability, and reusability were developed by using chitin derived from seafood waste as raw materials. The catalytic performance differences among these catalysts activated by different methods were investigated by hydrogenation of nitroaromatic compounds. The results showed that the multilayer hierarchical pore structure and abundance of hydroxyl and acetamido groups in chitin provided ample anchoring sites for Pt nanoparticles (NPs), ensuring the high dispersion of Pt NPs. Moreover, the interconnected channels between chitin nanofibrous microspheres facilitated rapid transport of reaction substrates. The best Pt/Chitin catalyst exhibited excellent catalytic activity and broad substrate applicability in hydrogenation of nitroaromatic compounds. Significantly, even after 20 runs, no discernible deactivation of activity was observed, demonstrating exceptional catalytic reusability. The application of seafood waste-based catalysts is conducive to the development of a green/sustainable society.

α-synuclein-lack expression rescues methamphetamine-induced mossy fiber degeneration in dorsal hippocampal CA3.

Methamphetamine (METH) - induced cognitive impairments may be related to synaptic degeneration at mossy fiber terminals, critical for spatial memory formation in hippocampal circuits. We have previously found METH-induced neurodegeneration in the striatum by increasing the α-synuclein (α-SYN) level. However, whether and how the METH-induced mossy fiber degeneration is also blamed for the abnormal accumulation of α-SYN remains to be elucidated. Chronic METH exposure decreased mossy fiber density but upregulatedα-SYN and phosphorylated TAU (TAU-pSer396) in hippocampal CA3, associated with glial cell overactivation, axonal neuropathies, and memory impairment. Notably, the knockout of the α-SYN gene significantly alleviated the METH-induced mossy fiber degeneration and memory impairment. Meanwhile, the TAU-pSer396 accumulation and glial activation were ameliorated by α-SYN knockout. Our findings suggest an essential role of α-SYN in mediating METH-induced mossy fiber degeneration, providing promising therapeutic and prophylactic targets for METH-related neurodegenerative diseases.

Highly dispersed palladium nano-catalyst anchored on N-doped nanoporous carbon microspheres derived from chitosan for efficient and stable hydrogenation of quinoline.

Under the background of green chemistry, the synthesis of N-heterocycles using efficient, stable and long-life catalysts has still faced great challenges. Herein, we used biomass resource chitosan to fabricate a nanoporous chitosan carbon microsphere (CCM), and successfully designed a stable and efficient Pd nano-catalyst (CCM/Pd). Various physicochemical characterizations provided convincible evidences that the palladium nanoparticles (NPs) were tightly and evenly dispersed on the CCM with a mean diameter of 2.28 nm based on the nanoporous structure and abundant functional N/O groups in CCM. Importantly, the graphitized constructure, the formed defects and larger surface area in CCM were able to promote the immobilization of Pd NPs and the electron transfer between Pd and CCM, thereby significantly improving the catalytic activity. The CCM/Pd catalyst was applied for hydrogenation of quinoline compounds, which showed excellent catalytic activity and durability, as well as good substrate applicability. The application of renewable biomass-based catalysts contributes to the progression of a green/sustainable society.

Chitosan derived efficient and stable Pd nano-catalyst for high efficiency hydrogenation.

The design and development of green and efficient supported catalysts is the frontier direction in the field of green synthesis, which conforms to the strategic concept of green sustainable chemistry and "carbon neutrality". Herein, we used a renewable resource chitosan (CS) derived from seafood wastes of chitin as carriers to design two different chitosan-supported palladium (Pd) nano-catalysts through different activation methods. The Pd particles were firmly and uniformly dispersed on the chitosan microspheres due to the interconnected nanoporous structure and functional groups of chitosan, proved by diverse characterizations. The chitosan supported catalysts (Pd@CS) was applied to hydrogenation of 4-nitrophenol, which showed competitive catalytic activity compared to commercial Pd/C, un-supported nano-Pd and Pd(OAc)2 catalysts, as well as excellent catalytic activity, good reusability, long-life and broad applicability in selective hydrogenation of aromatic aldehydes, suggesting potential of applications in green industrial catalysis.

Fabrication of Biomass Derived Pt-Ni Bimetallic Catalyst and Its Selective Hydrogenation for 4-Nitrostyrene.

The hydrogenation products of aromatic molecules with reducible groups (such as C=C, NO2, C=O, etc.) are relatively critical intermediate compounds in fine chemicals, but how to accurately reduce only specific groups is still challenging. In this work, a bimetallic Pt-Ni/Chitin catalyst was prepared for the first time by using renewable biomass resource chitin as support. As the carrier, the chitin was constructed into porous nanofibrous microspheres through the sol-gel strategy, which was favorable for the adhesion of nano-metals and the exchange of reactive substances due to its large surface area, porous structure, and rich functional groups. Then the Pt-Ni/Chitin catalyst was applied to selective hydrogenation with the model substrate of 4-nitrostyrene. As the highly dispersed Pt-Ni NPs with abundant exposed active sites and the synergistic effect of bimetals, the Pt-Ni/Chitin catalyst could efficiently and selectively hydrogenate only NO2 or C=C with yields of ~99% and TOF of 660 h-1, as well as good stability. This utilization of biomass resources to build catalyst materials would be important for the green and sustainable chemistry.

Constructing an In Situ Polymer Electrolyte and a Na-Rich Artificial SEI Layer toward Practical Solid-State Na Metal Batteries.

Sodium is one of the most promising anode candidates for the beyond-lithium-ion batteries. The development of Na metal batteries with a high energy density, high safety, and low cost is desirable to meet the requirements of both portable and stationary electrical energy storage. However, several problems caused by the unstable Na metal anode and the unsafe liquid electrolyte severely hinder their practical applications. Herein, we report a facile but effective methodology to construct an in situ polymer electrolyte and Na-rich artificial solid-electrolyte interface (SEI) layer concurrently. The obtained integrated Na metal batteries display long cycling life and admirable dynamic performance with total inhibition of dendrites, excellent contact of the cathode/polymer electrolyte, and reduction of side reactions during cycling. The modified Na metal electrode with the in situ polymer electrolyte is stable and dendrite-free in repeated plating/stripping processes with a life span of above 1000 h. Moreover, this method is compatible with different cathodes that demonstrate outstanding electrochemical performance in full cells. We believe that this approach provides a practical solution to solid-state Na metal batteries.

Cellulose derived Pd nano-catalyst for efficient catalysis.

Using green, environmentally friendly and resource-rich cellulose as a raw material, a ligand-free and highly dispersed palladium (Pd) nano-catalyst was successfully prepared in a facile way. A variety of characterization results showed that the Pd nanoparticles (NPs) were uniformly spread on the cellulose nanoporous microspheres, with an average particle size of ∼2.75 nm. As a carrier, cellulose microspheres with nanoporous structure and rich -OH groups greatly promoted the attachment and distribution of the highly dispersed Pd NPs, along with the diffusion and exchange of reactants, so as to greatly promote the catalytic activity. In the Suzuki-Miyaura coupling reaction, the catalyst of C-Pd exhibited excellent catalytic activity (TOF up to 2126 h-1), broad applicability, and good recyclability with almost no active loss in 6 continuous runs. This utilizing of bioresources to build catalyst materials is important for sustainable chemistry.

Facile fabrication of highly dispersed Pd catalyst on nanoporous chitosan and its application in environmental catalysis.

With the development of society, the problem of environmental pollution is becoming increasingly serious, such as the typical pollution of nitro compounds or dyes in wastewater. An effective strategy to remove these organic pollutants is catalytic conversion, including converting them into more chemically valuable compounds. Herein, a nanoporous chitosan microsphere derived from seafood waste resources of chitin was constructed via sol-gel method, which was used as supports to successfully fabricate a highly dispersed Pd nano-catalyst (mean diameter ~ 1.8 nm) via a facile way based on its interconnected nanoporous structure and rich functional -OH/-NH2 groups. The synthetic catalyst was applied to the hydrogenation of toxic nitro compounds, which could efficiently and selectively catalyze the conversion of nitro compounds. The catalyst was also used for the degradation of some representative dyes, which also showed good activity and stability, suggesting potential of applications in green environmental governance.

Highly Dispersed Pd Clusters Anchored on Nanoporous Cellulose Microspheres as a Highly Efficient Catalyst for the Suzuki Coupling Reaction.

With the depletion of nonrenewable resources such as oil/coal/gas, more and more research studies began to focus on the high-value utilization of residual biomass resources. Herein, for the first time, honeycomb nanoporous microspheres fabricated from renewable biomass resources of cellulose were used as a carrier to fabricate a highly dispersed palladium (Pd) nanocatalyst. Various physicochemical characterizations presented convincing pieces of evidence for the good dispersion of Pd clusters with a mean diameter of 1.6 nm. As the carrier, cellulose microspheres with an interconnected nanoporous structure contributed to the adhesion and dispersion of Pd particles, and their rich hydroxyl groups could fix the Pd particles. Importantly, the cellulose matrix could in situ induce the formation of metallic Pd(0) during calcination without a reductant. The cellulose/Pd catalyst was applied to the Suzuki coupling reaction, which exhibited promising catalytic activity compared to commercial Pd/C and unsupported homogeneous Pd(OAc)2 catalysts, as well as good stability. The utilization of the residual biomass resource to build catalyst materials would be important for the sustainable chemistry.

Chitin microsphere supported Pd nanoparticles as an efficient and recoverable catalyst for CO oxidation and Heck coupling reaction.

Chitin derived from seafood wastes is a sustainable biopolymer, which can be used to constructe new materials to reduce the environmental pollution caused by non-biodegradable plastics. Herein, nanofibrous microspheres fabricated from chitin solution were used as carriers to construct three different chitin-supported Pd catalysts through diverse activation methods, subsequently revealed their differences in structure and performance. The palladium nanoparticles were firmly and highly dispersed on the microspheres due to the interconnected nanofibrous networks and functional groups of chitin, confirmed by various physicochemical characterizations. As the best candidate catalyst of Pd/chitin-Ar, in the CO oxidation reaction, which achieved 100% CO conversion with a lower Pd content, and exhibited excellent stability in 24-hours cycle reaction. Importantly, the catalyst was further applied in Heck coupling reaction, which also displayed competitive catalytic activity and stability (∼6runs, 94%). This utilizing of biomass resource to build catalyst materials would be important for the sustainable chemistry.

Facile Construction of a Highly Dispersed Pt Nanocatalyst Anchored on Biomass-Derived N/O-Doped Carbon Nanofibrous Microspheres and Its Catalytic Hydrogenation.

With the depletion of nonrenewable resources and the increasingly serious "white pollution" caused by nondegradable plastics, using renewable biomass resources such as chitin to fabricate materials is a green and sustainable pathway. Herein, for the first time, we used N/O-doped carbon nanofibrous microspheres (CNMs) derived from renewable chitin as carriers to successfully construct a highly dispersed platinum nanocatalyst via a facile way. Various physicochemical characterizations provided reliable evidence for the ultrafine and well-dispersed platinum nanoparticles with an average diameter of 2.3 nm. As the supporting framework, the CNM with interconnected nanofibrous networks and a large surface area facilitated the adhesion and dispersion of Pt particles. Meanwhile, the inherent N/O-containing functional groups and the defects in carbonized chitin could anchor the platinum tightly. The CNM/Pt catalyst was further examined for hydrogenation, and it exhibited promising catalytic activity and stability (∼5 runs, 91%) and a broad applicability. This utilization of biomass resources to build catalyst materials would be important for the green and sustainable chemistry.

Size-controllable ultrafine palladium nanoparticles immobilized on calcined chitin microspheres as efficient and recyclable catalysts for hydrogenation.

In the present work, chitin microspheres were impregnated at different concentrations of palladium salt solution to generate the precursor-Pd2+/chitin, and then a series of size-controllable palladium nanocatalysts (Pd@chitin) were successfully constructed by calcining the composite microspheres. Transmission electron microscopy (TEM) and X-ray absorption spectroscopy (XAS) provided reliable evidence for well-dispersed and ultrafine palladium nanoparticles (Pd NPs) with mean diameters from about 1 to 3 nm. Chitin microspheres, as the supporting framework of these catalysts, played a significant role for stabilizing the highly dispersed Pd NPs based on their abundant functional groups and large surface areas. Moreover, the chitin matrix acted as a reductant for the precursor-Pd2+ during calcination, and the calcination process made Pd@chitin more stable. These Pd@chitin catalysts were further tested for the hydrogenations of styrene and benzaldehyde, and they displayed superior catalytic activities compared to commercial Pd/C and unsupported homogeneous Pd(OAc)2 catalysts. Notably, the most active catalyst of 1.2 wt% Pd@chitin had a highly competitive turnover frequency (TOF) of 50 000 h-1 in the hydrogenation of styrene, and the catalyst could be repeatedly used for more than 10 cycles with no decay of the catalytic activity, suggesting potential industrial applications.

Study on Foaming Quality and Impact Property of Foamed Polypropylene Composites.

In the present work, foamed polypropylene (PP) composites were prepared by chemical foaming technology, and the foaming quality and impact property of the foamed PP composites were studied. The results showed that the foaming quality was significantly improved after the introduction of thermoplastic rubber (TPR) and polyolefin elastomer (POE). Meanwhile, it was found that the impact property depended on the intrinsic toughness and contribution of foams (cells) to the PP composites. Furthermore, the data regarding impact property in low temperature showed that when the temperature was between -80 and -20 °C, the impact properties of the foamed PP composites were higher than that of the unfoamed sample, which was due to the impact property being completely contributed by cells under this condition. Meanwhile, when the temperature ranged from -20 to 20 °C, the impact property of the unfoamed sample was higher, which was due to the PP matrix contributing more to the impact property under this temperature. This work significantly improved the foaming quality of foamed PP composites and provided reliable evidence for the improvement of impact property.