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Synthesis of boron nitride nanorod and its performance as a metalfree catalyst for oxidative desulfurization of diesel fuel

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Chinese Journal of Chemical Engineering 2024年第4期68卷 120-132页

作者： Tanaz Ghanadi Gholamreza Moradi Alimorad Rashidi Catalyst research center Faculty of Chemical and Petroleum EngineeringRazi UniversityKermanshahIran Nanotechnology research center Research Institute of Petroleum Industry(RIPI)TehranIran

In order to reduce the sulfur compounds in diesel fuel,boron nitride(BN)has been used as a novel metal efree catalyst in the present research.This nanocatalyst was synthesized via template-free approach followed by heating treatment at 900℃in nitrogen atmosphere that the characteristics of the sample were identified by the X-ray diffraction,Fourier-transform infrared spectroscopy,Raman spectroscopy,field emission scanning electron microscopy,transmission electron microscopy,atomic force microscopy,and N2 adsorptionedesorption isotherms.The results of structural and morphological analysis represented that BN has been successfully synthesized.The efficacy of the main operating parameters on the process was studied by using response surface methodology based on the BoxeBehnken design method.The prepared catalyst showed high efficiency in oxidative desulfurization of diesel fuel with initial sulfur content of 8040 mg·kg^(-1)S.From statistical analysis,a significant quadratic model was obtained to predict the sulfur removal as a function of efficient parameters.The maximum efficiency of 72.4%was achieved under optimized conditions at oxidant/sulfur molar ratio of 10.2,temperature of 71℃,reaction time of 113 min,and catalyst dosage of 0.36 g.Also,the reusability of the BN was studied,and the result showed little reduction in activity of the catalyst after 10 times regeneration.Moreover,a plausible mechanism was proposed for oxidation of sulfur compounds on the surface of the catalyst.The present study shows that BN materials can be selected as promising metal-free catalysts for desulfurization process.

关键词： Desulfurization Boron nitride(BN)nanostructure Experimental design BoxeBehnken

Intranasal administration of stem cell-derived exosomes for central nervous system diseases

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Neural Regeneration research 2024年第6期19卷 1249-1255页

作者： Shuho Gotoh Masahito Kawabori Miki Fujimura Department of Neurosurgery Hokkaido University Graduate School of Medicine

Exosomes, lipid bilayer-enclosed small cellular vesicles, are actively secreted by various cells and play crucial roles in intercellular communication. These nanosized vesicles transport internalized proteins, mRNA, miRNA, and other bioactive molecules. Recent findings have provided compelling evidence that exosomes derived from stem cells hold great promise as a therapeutic modality for central nervous system disorders. These exosomes exhibit multifaceted properties including antiapoptotic, anti-inflammatory, neurogenic, and vasculogenic effects. Furthermore, exosomes offer several advantages over stem cell therapy, such as high preservation capacity, low immunogenicity, the ability to traverse the blood-brain barrier, and the potential for drug encapsulation. Consequently, researchers have turned their attention to exosomes as a novel therapeutic avenue. Nonetheless, akin to the limitations of stem cell treatment, the limited accumulation of exosomes in the injured brain poses a challenge to their clinical application. To overcome this hurdle, intranasal administration has emerged as a non-invasive and efficacious route for delivering drugs to the central nervous system. By exploiting the olfactory and trigeminal nerve axons, this approach enables the direct transport of therapeutics to the brain while bypassing the blood-brain barrier. Notably, exosomes, owing to their small size, can readily access the nerve pathways using this method. As a result, intranasal administration has gained increasing recognition as an optimal therapeutic strategy for exosomebased treatments. In this comprehensive review, we aim to provide an overview of both basic and clinical research studies investigating the intranasal administration of exosomes for the treatment of central nervous system diseases. Furthermore, we elucidate the underlying therapeutic mechanisms and offer insights into the prospect of this approach.

关键词： central nervous system disease exosome extracellular vesicle intranasal administration stem cell

Recent progress in functional modification and crosslinking of bioprosthetic heart valves

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Regenerative Biomaterials 2024年第1期3卷 1-16页

作者： Cheng Zheng Li Yang Yunbing Wang National Engineering research center for Biomaterials Sichuan UniversityChengdu 610064China

Valvular heart disease(VHD),clinically manifested as stenosis and regurgitation of native heart valve,is one of the most prevalent cardiovascular diseases with high mortality.Heart valve replacement surgery has been recognized as golden standard for the treatment of VHD.Owing to the clinical application of transcatheter heart valve replacement technic and the excellent hemodynamic performance of bioprosthetic heart valves(BHVs),implantation of BHVs has been increasing over recent years and gradually became the preferred choice for the treatment of VHD.However,BHVs might fail within 10-15 years due to structural valvular degeneration(SVD),which was greatly associated with drawbacks of glutaraldehyde crosslinked BHVs,including cytotoxicity,calcification,component degradation,mechanical failure,thrombosis and immune response.To prolong the service life of BHVs,much effort has been devoted to overcoming the drawbacks of BHVs and reducing the risk of SVD.In this review,we summarized and analyzed the research and progress on:(i)modification strategies based on glutaraldehyde crosslinked BHVs and(ii)nonglutaraldehyde crosslinking strategies for BHVs.

关键词： bioprosthetic heart valves modification crosslinking anticalcification antithrombosis

On-surface synthesis and characterization of polyynic carbon chains

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National Science Review 2024年第3期11卷 192-199页

作者： Wenze Gao Wei Zheng Luye Sun Faming Kang Zheng Zhou Wei Xu Interdisciplinary Materials research center School of Materials Science and Engineering Tongji University

Carbyne, an elusive sp-hybridized linear carbon allotrope, has fascinated chemists and physicists for decades. Due to its high chemical reactivity and extreme instability, carbyne was much less explored in contrast to the sp2-hybridized carbon allotropes such as graphene. Herein, we report the on-surface synthesis of polyynic carbon chains by demetallization of organometallic polyynes on the Au（111） surface;the longest one observed consists of ～60 alkyne units（120 carbon atoms）. The polyynic structure of carbon chains with alternating triple and single bonds was unambiguously revealed by bond-resolved atomic force microscopy. Moreover, an atomically precise polyyne, C14, was successfully produced via tip-induced dehalogenation and ring-opening of the decachloroanthracene molecule(C14Cl10) on a bilayer NaCl/Au（111） surface at 4.7 K, and a band gap of 5.8 eV was measured by scanning tunnelling spectroscopy,in a good agreement with the theoretical HOMO–LUMO gap（5.48 eV）.

关键词： polyyne scanning probe microscopy carbon allotrope on-surface synthesis organometallic polyyne

Evaluation of excavation damaged zones(EDZs)in Horonobe Underground research Laboratory(URL)

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第2期16卷 365-378页

作者： Koji Hata Sumio Niunoya Kazuhei Aoyagi Nobukatsu Miyara Obayashi Corporation Technology Research InstituteTechnology DivisionKiyoseTokyo204-8558Japan Obayashi Corporation Nuclear Facilities DivisionSinagawaTokyo108-8502Japan Japan Atomic Energy Agency Horonobe Underground Research CenterHoronobeHokkaido098-3224Japan

Excavation of underground caverns,such as mountain tunnels and energy-storage caverns,may cause the damages to the surrounding rock as a result of the stress redistribution.In this influenced zone,new cracks and discontinuities are created or propagate in the rock mass.Therefore,it is effective to measure and evaluate the acoustic emission(AE)events generated by the rocks,which is a small elastic vibration,and permeability change.The authors have developed a long-term measurement device that incorporates an optical AE(O-AE)sensor,an optical pore pressure sensor,and an optical temperature sensor in a single multi-optical measurement probe(MOP).Japan Atomic Energy Agency has been conducting R&D activities to enhance the reliability of high-level radioactive waste(HLW)deep geological disposal technology.In a high-level radioactive disposal project,one of the challenges is the development of methods for long-term monitoring of rock mass behavior.Therefore,in January 2014,the long-term measurements of the hydro-mechanical behavior of the rock mass were launched using the developed MOP in the vicinity of 350 m below the surface at the Horonobe Underground research center.The measurement results show that AEs occur frequently up to 1.5 m from the wall during excavation.In addition,hydraulic conductivity increased by 2e4 orders of magnitude.Elastoplastic analysis revealed that the hydraulic behavior of the rock mass affected the pore pressure fluctuations and caused micro-fractures.Based on this,a conceptual model is developed to represent the excavation damaged zone(EDZ),which contributes to the safe geological disposal of radioactive waste.

关键词： Excavation damaged zone(EDZ) Optical sensor Long-term monitoring Acoustic emission(AE) Shaft sinking

The influence of inter-band rock on rib spalling in longwall panel with large mining height

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International Journal of Mining Science and Technology 2024年第4期34卷 427-442页

作者： Jiachen Wang Meng Li Zhaohui Wang Zheng Li Han Zhang Shixiong Song School of Energy and Mining Engineering China University of Mining and Technology-BeijingBeijing 100083China Coal Industry Engineering research center of Top-coal Caving Mining Beijing 100083China Faculty of Engineering Hokkaido UniversitySapporo 060-8628Japan

In order to improve rib stability,failure criteria and instability mode of a thick coal seam with inter-band rock layer are analysed in this study.A three-dimensional mechanical model is established for the rib by considering the rock layer.A safety factor is defined foy the rib,and it is observed that the safety factor exhibits a positive correlation with the thickness and strength of the inter-band rock.A calculation method for determining critical parameters of the rock layer is presented to ensure the rib stability.It is revealed that incomplete propagation of the fracture at the hard rock constitutes a fundamental prerequisite for ensuring the rib stability.The influence of the position of the inter-band rock in the coal seam on failure mechanism of the rib was thoroughly investigated by developing a series of physical models for the rib at the face area.The best position for the inter-band rock in the coal seam is at a height of 1.5 m away from the roof line,which tends to provide a good stability state for the rib.For different inter-band rock positions,two ways of controlling rib by increasing supports stiffness and flexible grouting reinforcement are proposed.

关键词： Rib spalling Inter-band rock Large mining height Limit analysis Physical model experiment Numerical simulation

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Analysis of deformation mechanisms in magnesium single crystals using a dedicated four-point bending tester

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Journal of Magnesium and Alloys 2024年第5期12卷 1911-1917页

作者： Yutaka Yoshida Rikuto Izawa Kenji Ohkubo Faculty of Engineering Kitami Institute of Technology Graduate student Department of Mechanical and Electrical Engineering Kitami Institute of Technology Kyokuto Kaihatsu Kogyo Co. Ltd. center for Advanced research of Materials Faculty of Engineering Hokkaido University

In this study, we explored the deformation mechanisms of Mg single crystals using a combination of scanning electron microscopy and electron backscattered diffraction in conjunction with a dedicated four-point bending tester. We prepared two single-crystal samples,oriented along the and directions, to assess the mechanisms of deformation when the initial basal slip was suppressed. In the sample, the primary {■} twin(T1) was confirmed along the direction of the sample on the compression side with an increase in bending stress. In the sample, T1 and the secondary twin(T2) were confirmed to be along the direction, with an orientation of ±60° with respect to the bending stress direction, and their direction matched with(0001) in T1 and T2. This result implies that crystallographically, the basal slip occurs readily. In addition, the sample showed the double twin in T1 on the compression side and the tertiary twin along the direction on the tension side. These results demonstrated that the maximum bending stress and displacement changed significantly under the bend loading because the deformation mechanisms were different for these single crystals.Therefore, the correlation between bending behavior and twin orientation was determined, which would be helpful for optimizing the bending properties of Mg-based materials.

关键词： Four-point bending Magnesium single crystal Twinning Basal slip Scanning electron microscopy Electron backscatter diffraction

Comparative analysis between single-train passing and double-train intersection in a tunnel

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2024年第5期25卷 429-442页

作者： Jianming DU Qian FANG Xuan ZHANG Hualao WANG Bridge and Tunnel research center Research Institute of Highway Ministry of TransportBejing 100088China Tunnel and Underground Engineering research center of Ministry of Education Beijing Jiaotong UniversityBeijing 00044China

Aerodynamic pressure significantly impacts the scientific evaluation of tunnel service performance.The aerodynamic pressure of two trains running in a double-track tunnel is considerably more complicated than that of a single train.We used the numerical method to investigate the difference in aerodynamic pressure between a single train and two trains running in a double-track tunnel.First,the numerical method was verified by comparing the results of numerical simulation and on-site monitoring.Then,the characteristics of aerodynamic pressure were studied.Finally,the influence of various train-tunnel factors on the characteristics of aerodynamic pressure was investigated.The results show that the aerodynamic pressure variation can be divided into stage I:irregular pressure fluctuations before the train tail leaves the tunnel exit,and stage II:periodic pressure declines after the train tail leaves the tunnel exit.In addition,the aerodynamic pressure simultaneously jumps positively or drops negatively for a single train or two trains running in double-track tunnel scenarios.The pressure amplitude in the two-train case is higher than that for a single train.The maximum positive peak pressure difference(P_(STP))and maximum negative peak pressure difference(P_(STN))increase as train speed rises to the power from 2.256 to 2.930 in stage I.The P_(STP) and P_(STN) first increase and then decrease with the increase of tunnel length in stage I.The P_(STP) and P_(STN) increase as the blockage ratio rises to the power from 2.032 to 2.798 in stages I and II.

关键词： Railway tunnel Aerodynamic effect Pressure characteristic Train speed Tunnel length Blockage ratio

Chromosome-level genome assembly of the Asian citrus psyllid,Diaphorina citri

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Insect Science 2024年第1期31卷 13-27页

作者： Shuang Lei Shi-Jiang Yu Qi Pan Li-Li Ding Si-Chen Li Lu-Yan Cheng Shu-Qi Wang Bing-Hai Lou Jun He Cui-Yun Lei Lin Cong Hao-Qiang Liu Xue-Feng Wang Chun Ran Citrus research Institute Southwest University/Chinese Academy of Agricultural SciencesNational Engineering Research Center for CitrusChongqingChina

Diaphorina citri is a global citrus pest.As a vector insect,it can transmit the causative agents of citrus huanglongbing,causing irreversible losses to the citrus industry.The acquisition of genomic information can provide a molecular genetic basis for effective control of D.citri.Here,the DNBSEQ™,Oxford Nanopore Technologies,and Hi-C technologies are applied to generate a high-quality chromosome-level genome of D.citri.The genome size of D.citri was 523.78 Mb with a scaffold N50 of 47.05 Mb distributed on 13 chromosomes.A total of 250.64 Mb(47.85%)repeat sequences and 24048 protein-coding genes were predicted.Genome resequencing of female and male individuals indicated that the sex chromosome system of D.citri is XO.Phylogenetic analysis demonstrated that D.citri and Pachypsylla venusta,which separated from their most recent common ancestor about 336.62 million years ago,were the most closely related.Additionally,we identified genes potentially involved in detoxification metabolism,pathogen transmission,and honeydew secretion for further investigation.The high-quality genome provides an important reference for developing effective management strategies of D.citri.

关键词： Asian citrus psyllid chromosome-level genome comparative genomics cytochrome P450 detoxification Huanglongbing