A building blocks strategy is an effective approach for constructing the large molecular systems. Herein, we demonstrate that high‐resolution electro‐spray ionization mass spectrometry (HRESI‐MS) ...provides an effective chance to insight the assemble process of the building blocks and guides the construction of high‐nuclearity metal clusters on the basis of the reaction of Ti(OiPr)4, Eu(acac)3, and salicylic acid. The time‐dependent HRESI‐MS indicates that not only a Eu3Ti building block can be formed, but that it can further assemble into a Eu24Ti8 compound. Temperature‐dependent HRESI‐MS reveals that increase of the reaction temperature favors the formation and crystallization of the stable Eu24Ti8 structure. Single‐crystal structural analysis demonstrates that the Eu24Ti8 has a wheel‐like structure with diameter of ca. 4.1 nm and is the highest nuclearity lanthanide‐titanium oxo cluster reported to date.
Wheely big: Under the guidance of the time‐ and temperature‐dependent HRESI‐MS of the reaction, a wheel‐like Eu24Ti8 cluster was synthesized, which is the highest nuclearity lanthanide‐titanium oxo cluster reported to date.
Aim
Spinal cord injury (SCI) involves multiple pathological processes. Ferroptosis has been shown to play a critical role in the injury process. We wanted to explore whether zinc can inhibit ...ferroptosis, reduce inflammation, and then exert a neuroprotective effect.
Methods
The Alice method was used to establish a spinal cord injury model. The Basso Mouse Scale (BMS), Nissl staining, hematoxylin‐eosin staining, and immunofluorescence analysis were used to investigate the protective effect of zinc on neurons on spinal cord neurons and the recovery of motor function. The regulation of the nuclear factor E2/heme oxygenase‐1 (NRF2/HO‐1) pathway was assessed, the levels of essential ferroptosis proteins were measured, and the changes in mitochondria were confirmed by transmission electron microscopy and 5,5′,6,6′‐tetrachloro‐1,1′,3,3′‐tetraethyl‐imidacarbocyanine iodide (JC‐1) staining. In vitro experiments using VSC4.1 (spinal cord anterior horn motor neuroma cell line), 4‐hydroxynonenal (4HNE), reactive oxygen species (ROS), superoxide dismutase (SOD), malondialdehyde (MDA), glutathione (GSH), lipid peroxides, and finally the levels of inflammatory factors were detected to assess the effect of zinc.
Results
Zinc reversed behavioral and structural changes after SCI. Zinc increased the expression of NRF2/HO‐1, thereby increasing the content of glutathione peroxidase 4 (GPX4), SOD, and GHS and reducing the levels of lipid peroxides, MDA, and ROS. Zinc also rescued injured mitochondria and effectively reduced spinal cord injury and the levels of inflammatory factors, and the NRF2 inhibitor Brusatol reversed the effects of zinc.
Conclusion
Zinc promoted the degradation of oxidative stress products and lipid peroxides through the NRF2/HO‐1 and GPX4 signaling pathways to inhibit ferroptosis in neurons.
Mechanisms underlying the repair of spinal cord injury through inhibiting ferroptosis with zinc.
The deregulation of microRNAs (miRNAs) plays an important role in human hepatocarcinogenesis. In this study, we highlight exosomes as mediators involved in modulating miRNA profiles in hepatocellular ...carcinoma (HCC) cells. First, we examined the different miRNA expression profiles in HCC cells and HCC cell–derived exosomes. Next, coculture experiments indicated that HCC cell–derived exosomes promoted the cell growth, migration, and invasion of HCC cells and had the ability to shuttle miRNAs to recipient cells. Further, our data showed that Vps4A, a key regulator of exosome biogenesis, was frequently down‐regulated in HCC tissues. The reduction of Vps4A in HCC tissues was associated with tumor progression and metastasis. In vitro studies revealed that Vps4A repressed the growth, colony formation, migration, and invasion of HCC cells. We further investigated the role and involvement of Vps4A in suppressing the bioactivity of exosomes and characterized its ability to weaken the cell response to exosomes. By small RNA sequencing, we demonstrated that Vps4A facilitated the secretion of oncogenic miRNAs in exosomes as well as accumulation and uptake of tumor suppressor miRNAs in cells. A subset of Vps4A‐associated miRNAs was identified. Kyoto Encyclopedia of Genes and Genomes pathway analysis indicated that the phosphatidylinositol‐3‐kinase/Akt signaling pathway was the most likely candidate pathway for modulation by these miRNAs. Indeed, we proved that the phosphatidylinositol‐3‐kinase/Akt pathway was inactivated by Vps4A overexpression. Conclusion: Exosome‐mediated miRNA transfer is an important mechanism of self‐modulation of the miRNA expression profiles in HCC cells, and Vps4A may function as a tumor suppressor, which utilizes exosomes as mediators to regulate the secretion and uptake of miRNAs in hepatoma cells; these observations provide new insights into the development of HCC. (Hepatology 2015;61:1284–1294)
The integration of III-V and Si multi-junction solar cells as photovoltaic devices has been studied in order to achieve high photovoltaic conversion efficiency. However, large differences in the ...coefficients of thermal expansion and the lattice parameters of GaAs, Si, and InGaAs have made it difficult to obtain high-efficiency solar cells grown as epilayers on Si and InP substrates. In this paper, two types of devices, including GaInP/GaAs stacked on Si (GaInP/GaAs//Si) and GaInP/GaAs stacked on InGaAs (GaInP/GaAs//InGaAs), are fabricated via mechanical stacking and wire bonding technologies. Mechanically stacked GaInP/GaAs//Si and GaInP/GaAs//InGaAs triple-junction solar cells are prepared via glue bonding. Current-voltage measurements of the two samples are made at room temperature. The short-circuit current densities of the GaInP/GaAs//Si and GaInP/GaAs//InGaAs solar cells are 13.37 and 13.66 mA/cm
, while the open-circuit voltages of these two samples are measured to be 2.71 and 2.52 V, respectively. After bonding the GaInP/GaAs dual-junction with the Si and InGaAs solar cells, the conversion efficiency is relatively improved by 32.6% and 30.9%, respectively, compared to the efficiency of the GaInP/GaAs dual-junction solar cell alone. This study demonstrates the high potential of combining mechanical stacked with wire bonding and ITO films to achieve high conversion efficiency in solar cells with three or more junctions.
Tin perovskite nanomaterial is one of the promising candidates to replace organic lead halide perovskites in lighting applications. Unfortunately, the performance of tin-based systems is markedly ...inferior to those featuring toxic Pb salts. In an effort to improve the emission quantum efficiency of nanoscale 2D layered tin iodide perovskites through fine-tuning the electronic property of organic ammonium salts, we came to unveil the relationship between dielectric confinement and the photoluminescent properties of tin iodide perovskite nanodisks. Our results show that increasing the dielectric contrast for organic versus inorganic layers leads to a bathochromic shift in emission peak wavelength, a decrease of exciton recombination time, and importantly a significant boost in the emission efficiency. Under optimized conditions, a leap in emission quantum yield to a record high 21% was accomplished for the nanoscale thienylethylammonium tin iodide perovskite (TEA2SnI4). The as-prepared TEA2SnI4 also possessed superior photostability, showing no sign of degradation under continuous irradiation (10 mW/cm2) over a period of 120 h.
Abstract
Copper electrocatalysts have been shown to selectively reduce carbon dioxide to hydrocarbons. Nevertheless, the absence of a systematic study based on time-resolved spectroscopy renders the ...functional agent—either metallic or oxidative Copper—for the selectivity still undecidable. Herein, we develop an operando seconds-resolved X-ray absorption spectroscopy to uncover the chemical state evolution of working catalysts. An oxide-derived Copper electrocatalyst is employed as a model catalyst to offer scientific insights into the roles metal states serve in carbon dioxide reduction reaction (CO
2
RR). Using a potential switching approach, the model catalyst can achieve a steady chemical state of half-Cu(0)-and-half-Cu(I) and selectively produce asymmetric C
2
products - C
2
H
5
OH. Furthermore, a theoretical analysis reveals that a surface composed of Cu-Cu(I) ensembles can have dual carbon monoxide molecules coupled asymmetrically, which potentially enhances the catalyst’s CO
2
RR product selectivity toward C
2
products. Our results offer understandings of the fundamental chemical states and insights to the establishment of selective CO
2
RR.
Rationally designing active and durable catalysts for the oxygen evolution reaction (OER) is of primary importance in water splitting. Perovskite oxides (ABO3) with versatile structures and multiple ...physicochemical properties have triggered considerable interest in the OER. The leaching of A site cations can create nanostructures and amorphous motifs on the perovskite matrix, thus facilitating the OER process. However, selectively dissolving A site cations and simultaneously obtaining more active amorphous motifs derived from the B site cations remains a great challenge. Herein, a top‐down strategy is proposed to transform bulk crystalline perovskite (LaNiO3) into a nanostructured amorphous hydroxide by FeCl3 post‐treatment, resulting in an extremely low overpotential of 189 mV at 10 mA cm−2. The top‐down‐constructed amorphous catalyst with a large surface area has dual NiFe active sites, where high‐valence Ni3+‐based edge‐sharing octahedral frameworks are surrounded by interstitial distorted Fe octahedra and contribute to the superior OER performance. This top‐down strategy provides a valid way to design novel perovskite‐derived catalysts.
An amorphous NiFe‐based catalyst (a‐LNF(t‐d)) is constructed from LaNiO3 perovskite oxide through a top‐down strategy involving FeCl3 post‐treatment, which selectively dissolves the La ions and deposits the Fe ions. The a‐LNF(t‐d) sample, with large surface area and unusual electronic/geometrical structure shows extremely high oxygen evolution reaction (OER) activity and stability.
Hydrogen spillover is a well-known phenomenon in heterogeneous catalysis; it involves H
cleavage on an active metal followed by the migration of dissociated H species over an 'inert' support
. ...Although catalytic hydrogenation using the spilled H species, namely, spillover hydrogenation, has long been proposed, very limited knowledge has been obtained about what kind of support structure is required to achieve spillover hydrogenation
. By dispersing Pd atoms onto Cu nanomaterials with different exposed facets, Cu(111) and Cu(100), we demonstrate in this work that while the hydrogen spillover from Pd to Cu is facet independent, the spillover hydrogenation only occurs on Pd
/Cu(100), where the hydrogen atoms spilled from Pd are readily utilized for the semi-hydrogenation of alkynes. This work thus helps to create an effective method for fabricating cost-effective nanocatalysts with an extremely low Pd loading, at the level of 50 ppm, toward the semi-hydrogenation of a broad range of alkynes with extremely high activity and selectivity.
The discovered giant clusters are always highly symmetric owing to the spontaneous assembly of one or two basic units. Herein we report the Gd44Co28 crown and Gd95Co60 cage, formulated as ...Gd44Co28(IDA)20 (OH)72(CO3)12(OAc)28(H2O)64⋅(ClO4)24 and Na4Gd95 Co60(IDA)40(OH)150(CO3)40(OAc)58(H2O)164 ⋅ (ClO4)41 (H2IDA=iminodiacetic acid), respectively, by providing a library containing multiple low‐nuclearity units. The heart‐like units and crown‐like tetramer found in both compounds indicate unprecedented assembly levels, leading to an atypical geometry characteristic compared to the giant clusters directly assembled by regular units. These two clusters not only significantly increase the size of Ln−Co clusters but also exhibit the enhanced magnetic entropy change at ultra‐low temperatures. This work provided an effective way to fabricate cluster compounds with giant size and geometry complexity simultaneously.
By using a library containing multiple low‐nuclearity units that have compatible geometry but incompatible symmetry, rare Ln−Co giant clusters with atypical geometry and assembly levels were achieved.
We used discarded oyster shells to prepare vaterite calcium carbonate microparticles and explored the removal effects and the underlying mechanism toward several heavy metal ions. The removal ...efficiency for each ion type was: Pb2+ (99.9%), Cr3+ (99.5%), Fe3+ (99.3%), and Cu2+ (57.1%). With the exception of Cu2+, vaterite calcium carbonate particles exhibited excellent removal performance on all tested heavy metal ions, with exceptional results for Pb2+. The factor affecting the removal efficiency of heavy metal ions is shown to involve an ion exchange reaction between calcium and the heavy metal ions resulting in recrystallization. Vaterite calcium carbonate particles prepared by this method have the advantage of low price, easy synthesis, and reduction of environmental waste. Thus, this procedure for synthesizing vaterite CaCO3 provides an environmentally responsible method for preparing materials that can be economically incorporated into common consumer products such as household drinking water filtration systems.
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•Oyster shells-prepared CaCO3 has better removal efficiencies than commercial CaCO3.•Heavy metals removal could also be indirectly monitored via pH changes.•The CaCO3 remove heavy metal ions rapidly and be used in water treatments.
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