查找使用阿拉丁产品的科研文献

A robust and self-healing elastomer achieved by a thio-β-diketone-Cu(II) coordination and H-bonding dual crosslinked system

Xiaoming An,Jie Liu,Jia-Han Zhang,Xinxin Huang,Tangsong Zhu,Hongping Yan,Xudong Jia,Qiuhong Zhang

Elastomers possessing good mechanical strength and self-healing capability are showing great importance in stretchable electronics, since they can play the role of robust substrates for devices, and prolong the service life of devices. However, it is hard to balance the trade-off between the high mechanical strength and self-healing ability. Here we propose the synergetic strategy via combining thio-β-diketone-Cu2+ metal–ligand (M–L) coordination with hydrogen bonds in one system, through which high mechanical strength, good elasticity and self-healing ability are achieved. The elastomer displays excellent mechanical performances (with a fracture strength of 4.35 MPa and a fracture strain of 3400%). Meanwhile, the elastomer can realize a high self-healing efficiency (94%) within only 3 hours at 80 °C. X-ray absorption fine structure (XAFS) analysis demonstrates the reconfiguration of M–L coordination at the molecular level, and small angle X-ray scattering (SAXS) during stretching demonstrates the microphase structure change of the polymer at the nanoscale level. Based on the elastomer, a self-healable pressure sensor and a self-healable strain sensor are fabricated.

Rational design of engineered H-ferritin nanoparticles with improved siRNA delivery efficacy across an in vitro model of the mouse BBB

Ziwei Yuan,Bin Wang,Yilong Teng,William Ho,Bin Hu,Kofi Oti Boakye-Yiadom,Xiaoyang Xu,Xue-Qing Zhang

Gene therapy holds tremendous potential for the treatment of incurable brain diseases including Alzheimer's disease (AD), stroke, glioma, and Parkinson's disease. The main challenge is the lack of effective gene delivery systems traversing the blood–brain barrier (BBB), due to the complex microvessels present in the brain which restrict substances from the circulating blood passing through. Recently, increasing efforts have been made to develop promising gene carriers for brain-related disease therapies. One such development is the self-assembled heavy chain ferritin (HFn) nanoparticles (NPs). HFn NPs have a unique hollow spherical structure that can encapsulate nucleic acid drugs (NADs) and specifically bind to cancer cells and BBB endothelial cells (BBB ECs) via interactions with the transferrin receptor 1 (TfR1) overexpressed on their surfaces, which increases uptake through the BBB. However, the gene-loading capacity of HFn is restricted by its limited interior volume and negatively charged inner surface; therefore, these drawbacks have prompted the demand for strategies to remould the structure of HFn. In this work, we analyzed the three-dimensional (3D) structure of HFn using Chimera software (v 1.14) and developed a class of internally cationic HFn variants (HFn+ NPs) through arginine mutation on the lumenal surface of HFn. These HFn+ NPs presented powerful electrostatic forces in their cavities, and exhibited higher gene encapsulation efficacy than naive HFn. The top-performing candidate, HFn2, effectively delivered siRNA to glioma cells after traversing the BBB and achieved the highest silencing efficacy among HFn+ NPs. Overall, our findings demonstrate that HFn+ NPs obtained by this genetic engineering method provide critical insights into the future development of nucleic acid delivery carriers with BBB-crossing ability.

Construction of double cross-linking PEG/h-BN@GO polymeric energy-storage composites with high structural stability and excellent thermal performances

Rui Jing,Huanzhi Zhang,Chaowei Huang,Fucai Su,Bojing Wu,Zongxu Sun,Fen Xu,Lixian Sun,Yongpeng Xia,Hongliang Peng,Xiangcheng Lin,Bin Li,Yongjin Zou,Hailiang Chu,Pengru Huang,Erhu Yan

To improve phase-change behavior and thermal conductivity of the PEG-based polymeric SSPCMs, a series of SSPCMs with double cross-linking networks were constructed by introducing GO and hydroxylated h-BN into the polymer molecular chains of PEG-based SSPCMs through grafted polymerization and self-assembly. GO was the main hard supporting skeleton for the PEG segment, and h-BN as 2D thermal enhanced cells continuously was linked on the GO nano-sheets, forming into double cross-linking networks with PEG segments, which has good structural stability and regularity. Thus, the SSPCMs possessed good phase-change properties, excellent thermal reliability, and high thermal conductivity. Microscopies confirmed the successfully constructed chemical structure of the SSPCMs. Energy-storage capacities of the SSPCMs could reach 149.62 J/g, which displayed no obvious change after 100 thermal cycles, suggesting a good thermal cycling stability. Moreover, thermal conductivity of the prepared SSPCMs was enhanced by 71% compared with pure PEG, showing a good heat transfer efficiency. Therefore, this study represents a creative strategy towards the development of SSPCMs for thermal energy storage and thermal management applications.

Enhanced performance for total Cr removal using a novel h-BN supported nanoscale iron sulfide composite: stabilization effects and removal mechanism

Li Li,Junjie Chen,Guodong Sheng,Yixin Pan,Xiaojie Guo

In this study, a novel nanocomposite (FeS@h-BN) that FeS nanoparticles anchored onto h-BN nanosheets was synthesized for chromium (Cr(VI)) removal in aqueous solutions and characterized by SEM, TEM , XRD , FTIR, Zeta, and XPS . The effect of removal parameters including initial pH, temperature, FeS@h-BN dosage, the initial concentration of Cr(VI) and contact time were investigated. Experiment results revealed that h-BN as a stabilizer for FeS had good stability and effectively reduced FeS agglomeration. The remarkable performance of removing total Cr in aqueous solution was obtained by effectively converting Cr(VI) to Cr(III) on FeS and simultaneously adsorbing Cr(III) on h-BN. The adsorption capacity of FeS@h-BN for Cr(VI) was extremely sensitive to the pH and the optimum adsorption was 399.72 mg/g at pH of 1.0. In addition, the efficiency of removing Cr(VI) by FeS@h-BN increased with the increase of adsorbent dosage and Cr(VI) concentration, and the efficiency reached 100% at an adsorbent dosage of 0.30 g/L. The pseudo-second-order kinetic model can fully explain the experimental rate data. The mechanism of FeS@h-BN to remove Cr(VI) was adsorption and chemical reduction, of which chemical adsorption was the main one. These results revealed that h-BN as a stabilizer can improve the FeS stability and reactivity for the rapid removal of Cr(VI) contamination in water solution.

Synergistic effects of bimetals and hierarchical structures in Mg–Sn-Beta-H zeolites for lactic acid synthesis from biomass-derived carbohydrates

Meng Xia,Zheng Shen,Shaoze Xiao,Minyan Gu,Yalei Zhang

During the catalytic transformation of biomass into valuable chemicals, enhancing the yield of target products and inhibiting undesirable reactions are vital but challenging. In this study, a facile and efficient method for synthesizing a hierarchical bimetallic Mg–Sn-Beta-H zeolite was developed. Using this method, the simultaneous fabrication of catalytically active sites and hierarchical structures was achieved. Selective experiments and kinetic analysis confirmed that the catalytically active sites and hierarchical structures in the catalyst exhibited a clear synergistic effect on the transformation of glucose into lactic acid with a high yield of 62.7%, and the lactic acid yield remained above 58% after reusing the catalyst four times. An in-depth analysis of the synergistic catalysis mechanism demonstrated that strong and weak Lewis acidity in the catalytically active sites promoted the main reaction steps, including isomerisation and retro-aldol condensation, whereas the hierarchical structure induced by the introduction of magnesium into the parent Sn-Beta zeolite regulated the main reaction steps and suppressed the side reactions. The coupling of multifunctional active sites and hierarchical structures provides a new strategy for addressing the challenges of commercial lactic acid production.

Direct Electrochemical Oxidation of Benzylic C–H Bond by La2O3@C/CP Composite Electrode with Water as the Green Oxygen Source

Qifeng Yang,Yiming Mo

Selective oxidation of high-energy C–H bonds to produce carbonyl compounds is a fundamental transformation in fine chemical synthesis. Despite tremendous efforts, the development of green and safe strategies often suffers from harsh reaction conditions and uses homogeneous transition-metal catalysts. Herein, we present an electrochemical oxidation strategy that is green and safe for the direct oxidation of benzylic C–H bonds using La2O3 nanoparticles supported on a carbon paper (La2O3/CP) anode. La2O3/CP can selectively oxidize indane to indanone in 83% yield with 73% Faraday efficiency at room temperature. It also can oxidize different kinds of compounds with benzyl C–H bonds to produce the corresponding ketones with moderate-to-excellent yields. The oxygen source was confirmed to be water by an oxygen isotope (18O) tracer experiment. Additionally, the La2O3@C/CP composite electrode was reconfigured through carbonizing oleic acid to stabilize La2O3 on CP, resulting in an improved stability due to the reinforced catalyst embedding on CP, and retaining 81% initial activity after five cycles.

Enhancing aerobic oxidation of C–H bonds through efficient catalysis of iron MOF–derived Fe3C nanoparticles embedded in porous carbon catalysts

Lei Zhuang,Mingyuan Jian,Ruifang Xue,Nan Li,Jie Chen,Yanghe Fu,De–Li Chen,Weidong Zhu,Fumin Zhang

Developing efficient heterogeneous catalysts for the aerobic oxidation of C–H bonds using oxygen molecule as an oxidant to produce value–added aryl ketones is a challenging task. In this study, a series of cementite–iron–carbon composites (referred to as Fe–C–T, where T represents the pyrolysis temperature) were synthesized using a metal–organic–framework–mediated sacrificial template strategy. The Fe–C–T composites consist of highly dispersed Fe/(Fe 3 C or Fe 2 O 3 ) nanoparticles surrounded by graphitic carbon on porous carbon supports. Under mild reaction conditions (1 atm of O 2 pressure, 353 K, 12 h), with tert–butyl hydroperoxide (0.25 equiv.) as the initiator in a green solvent water, the prepared Fe–C–973 achieved a high conversion of 98.4 % for ethylbenzene and a selectivity of 98.7 % for acetophenone . This performance was markedly superior to the comparable Fe–C–873 and Fe–C–1073, as well as the commercially available Fe–based catalysts. Kinetic studies revealed that the catalytic system followed first–order kinetics for the substrate ethylbenzene, and the activation energy over Fe–C–973 was remarkably low of 40.4 kJ/mol. The highly distributed Fe 3 C nanoparticles embedded in the porous carbon framework were identified as the most active sites for the reaction.

NAD(P)H-triggered probe for dual-modal imaging during energy metabolism and novel strategy of enhanced photothermal therapy in tumor

Yang Tian,Wen-Li Jiang,Wen-Xin Wang,Guo-Jiang Mao,Yongfei Li,Chun-Yan Li

The reduced coenzymes (NADH and NADPH) are an important product in energy metabolism and closely related to the occurrence and development of cancer. So it is necessary to use a powerful detection tool to visualize NAD(P)H in energy metabolism of tumor cells and find a new strategy to improve cancer treatment based on NAD(P)H. Herein, a novel multifunctional probe (Cy-N) is synthesized with good near-infrared fluorescence (NIRF) response to NAD(P)H and the photoacoustic (PA) and photothermal properties are successfully activated by NAD(P)H. The probe is successfully applied in visualizing NAD(P)H in energy metabolism of tumor cells and imaging NAD(P)H in bacteria. Moreover, the probe can be used to image NAD(P)H in energy metabolism of tumor-bearing mice by dual-modal imaging (NIRF and PA). More importantly, in terms of the role of NAD(P)H in energy metabolism, the photothermal therapy (PTT) is activated by NAD(P)H and a novel strategy of enhanced PTT is proposed by injecting glucose. As far as we know, this is the first probe to detect NAD(P)H in energy metabolism through dual-modal imaging, and also the first probe to activate PTT based on NAD(P)H, which will provide important information of the diagnosis and treatment of cancer.

Crassifoside H ameliorates depressant behavior in chronic unpredictable mild stress rats by improving HPA axis dysfunction and inhibiting inflammation in hippocampus

Huina Li,Kefan Wu,Yue Zhang,Ning Li,Kaijin Wang

Enhancing the corrosion resistance of Q235 mild steel by incorporating poly(dopamine) modified h-BN nanosheets on zinc phosphate-silane coating

Mustafa Muhammad,Shihao Hu,Ruina Ma,An Du,Mengzhe Wang,Yongzhe Fan,Xue Zhao,Huazhen Yang,Chong Chong Li,Xiaoming Cao

Phosphate-silane coatings were developed on the Q235 mild steel by incorporating poly(dopamine) modified h-BNs into the zinc phosphating bath to enhance the corrosion resistance . The effects of PDA modified h-BNs with varying concentrations (0.10–0.90 g/L) on the surface modification, and corrosion resistance of the composite coatings were investigated. Results show that denser and uniform coatings were achieved for samples containing poly(dopamine) modified h-BN. Sample 0.60 g/L attained outstanding corrosion resistance, which is in one order of magnitude lower than the pure coatings with a current density of 1.95 × 10 −5 A/cm 2 . Modified h-BN effectively accelerates and enhances the corrosion resistance of the phosphate-silane coatings.

Synergistic functionalization of h-BN by mechanical exfoliation and PEI chemical modification for enhancing the corrosion resistance of waterborne epoxy coating

Youqing Wu,Yi He,Taigang Zhou,Chunlin Chen,Fei Zhong,Yunqing Xia,Peng Xie,Chen Zhang

The hexagonal boron nitride (h-BN) has extensive promise for metal corrosion protection due to its good impermeability to gas and liquid. However, the practical application of h-BN in polymer composites is limited by surface incompatibility. Herein, we prepared a homogeneous dispersion of h-BN in water-borne epoxy (EP) matrix by mechanical exfoliation and chemical modification, in which the h-BN powder was ultrasonic to obtain partially hydroxylated BN and the products were modified with water-soluble branched poly-ethyleneimine (PEI) via Lewis acid-base interaction. The electrochemical test (EIS and potentiodynamic polarization) and salt spray test in NaCl solution were used to analyze the corrosion resistance performance of composite coatings. The results show that PEI-BNNS/EP coating has superior and long-term anticorrosion performance for P110 mild steel. The impedance modulus (Z f  = 0.01 Hz) of PEI-BNNS/EP still has 6.63 × 10 7 Ω cm 2 after 70 days immersion in the 3.5 wt. % NaCl solution. The PEI has an important role for enhancing the anticorrosion property of PEI-BNNS/EP coating, which increases the dispersibility and compatibility of h-BN in EP and the crosslink density of epoxy resin. Our study gives a strategy for the preparation of easy dispersion h-BN nanosheets in large quantities, thus broadening its practical application in the polymer material field.

Effect of preparation and reaction conditions on the performance of In/H-Beta for selective catalytic reduction of NOx with CH4

Jiuhu Zhao,Gaige Zhang,Jiansheng He,Zhengzhong Wen,Zhi Li,Tingkun Gu,Ran Ding,Yongji Zhu,Rongshu Zhu

In/H-Beta catalyst was prepared by optimizing the support, concentration of ion exchange liquid and calcination temperature to investigate the effects of synthesis conditions on catalytic activity of selective catalytic reduction of NO x with CH 4 . The results showed that the In/H-Beta catalyst exhibited the superior activity when concentration of exchange liquid was 0.033 M and calcination temperature was 500 °C, the NO x removal ratio could reach 97.6%. In addition, reaction conditions could affect the catalytic performance. When O 2 concentration was 10%, CH 4 :NO ratio was no less than one, space velocity was lower than 23600 h −1 and NO initial concentration was no more than 700 ppm, In/H-Beta could exhibit superior catalytic activity. Moreover, the catalytic performances of In/H-Beta catalysts were discussed after enduring H 2 O or/and SO 2 . This novel strategy could open the door for selective catalytic reduction of NO x with CH 4 .