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Synthesis of Self-assembled Star/Linear Block Copolymer Blends via Aqueous RAFT Dispersion Polymerization

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Chinese Journal of Chemistry 2024年第14期42卷 1606-1614页

作者： Ruiming Wang Wenyu Zhu Li Zhang Xinxin Sheng Jianbo tan Department of Polymeric Materials and Engineering School of Materials and EnergyGuangdong University of TechnologyGuangzhouGuangdong510006 China Guangdong Provincial Key Laboratory of Functional Soft Condensed Matter GuangzhouGuangdong510006 China

Reversible addition-fragmentation chain transfer(RAFT)-mediated polymerization-induced self-assembly(PISA)of star block copolymer and linear block copolymer using a binary mixture of a star-like macro-RAFT agent and a linear macro-RAFT agent is *** this formulation,star block copolymer and diblock copolymer were formed simultaneously to generate colloidally stable star/linear block copolymer *** exclusion chromatography(SEC)analysis confirmed the presence of two types of polymers in the final *** molar ratio of the star-like macro-RAFT agent and the linear macro-RAFT agent has a significant impact on the morphology of polymer *** was found that increasing the amount of star-like macro-RAFT agent facilitated the formation of higher-order ***,effects of other reaction parameters including the length/number of the arm of the star-like macro-RAFT agent,degree of polymer(DP),monomer concentration on the morphology of star/linear block copolymer assemblies were also *** expect that this work will offer new possibilities for the scalable preparation of polymer assemblies with unique structures and functions.

关键词： Star block copolymer Reversible addition-fragmentation chain transfer Polymerization-induced self-assembly Livingpolymerization Copolymers

Macrocyclic trichothecenes from Myrothecium verrucaria PA 57 and their cytotoxic activity

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Chinese Journal of Natural Medicines 2024年第9期22卷 854-863页

作者： MO Jisong tan Yufen AI Wenjing LI Yunyun YUAN Yiyun JIANG Yueping XU Kangping tan Guishan WANG Wenxuan LI Jing LIU Shao Department of Pharmacy National Clinical Research Center for Geriatric DisordersXiangya HospitalCentral South UniversityChangsha 410008China Xiangya School of Pharmaceutical Sciences Central South UniversityChangsha 410008China

Four novel macrocyclic trichothecenes,termed mytoxins D-G(1-4),along with four known analogs(5-8),were isolated from the ethyl acetate extract of fermented rice inoculated with the fungus Myrothecium verrucaria *** compound features a tricyclic 12,13-epoxytrichothec-9-ene(EPT)***,mytoxin G(4)represents the first instance of a macrocyclic trichothecene incorporating a glucosyl unit within the trichothecene *** structures of the newly identified compounds were elucidated through comprehensive spectroscopic analysis combined with quantum chemical *** isolated compounds demonstrated cytotoxic activity against the CAL27 and HCT116 cell lines,which are models for human oral squamous cell carcinoma and colorectal cancer,***,mytoxin D(1)and mytoxin F(3)exhibited pronounced cytotoxic effects against both cancer cell lines,with IC_(50)values ranging from 3 to 6 nmol·L^(-1).Moreover,compounds 1 and 3 were found to induce apoptosis in HCT116 cells by activating caspase-3.

关键词： Macrocyclic trichothecenes Myrothecium verrucaria Cytotoxicity Secondary metabolite Soil fungi

Mg/MgO interfaces as efficient hydrogen evolution cathodes causing accelerated corrosion of additive manufactured Mg alloys:A DFT analysis

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Journal of Magnesium and Alloys 2024年第1期12卷 110-119页

作者： Man-Fai Ng Kai Xiang Kuah Teck Leong tan Daniel John Blackwood Department of Materials Science&Engineering National University of Singapore9 Engineering Drive 1Singapore 117575Republic of Singapore Institute of High Performance Computing(IHPC) Agency for ScienceTechnology and Research(A∗STAR)1 Fusionopolis Way#16-16 ConnexisSingapore 138632Republic of Singapore

The corrosion rates of additive-manufactured Mg alloys are higher than their as-cast counterparts,possibly due to increased kinetics for the hydrogen evolution reaction on secondary phases,which may include oxide *** Kelvin Probe Force Microscopy demonstrated that MgO inclusions could act as cathodes for Mg corrosion,but their low conductivity likely precludes ***,the density of state calculations through density functional theory using hybrid HSE06 functional revealed overlapping electronic states at the Mg/MgO interface,which facilitates electron transfers and participates in redox *** determination of the hydrogen absorption energy at the Mg/MgO interface reveals it to be an excellent catalytic site,with HER being found to be a factor of 23x more efficient at the interface than on metallic *** results not only support the plausibility of the Mg/MgO interface being an effective cathode to the adjacent anodic Mg matrix during corrosion but also contribute to the understanding of the enhanced cathodic activities observed during the anodic dissolution of magnesium.

关键词： Magnesium Magnesium oxide Interface Hydrogen evolution DFT

Numerical investigation of the photo-thermal characteristics of a direct absorption solar collector using Monte Carlo and finite volume methods

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Science China(Technological Sciences) 2024年第8期67卷 2436-2448页

作者： ZHU YanLong LI SuNing FAN JianHua KONG WeiQiang YUAN Yuan tan HePing School of Energy Science and Engineering Harbin Institute of TechnologyHarbin 150001China Department of Civil Engineering and Mechanical Engineering Technical University of DenmarkKoppels AlléBuilding 4042800 Kgs.LyngbyDenmark School of Vehicle and Energy Yanshan UniversityQinhuangdao 066004China

In this study, a novel model of photothermal conversion in a direct absorption solar collector based on the Monte Carlo and finite volume methods was built and validated and the temperatures of the novel and traditional solar collectors were compared. The sensitivity of the parameters to the radiative heat loss was investigated. Finally, the radiative heat transfer characteristics were discussed using the radiative exchange factor. The results of this study validated the advantages of the novel solar collector at both the surface and fluid temperatures. Under the conditions used in this study, the maximum temperature difference of the novel solar collector was 30 K, compared with 193 K for the traditional solar collector. Furthermore, the collector was divided into several units along the flow direction. The radiative exchange factor indicated that with an increase in the attenuation coefficient, the percentage of radiation intensity in the total solar radiation absorbed by the corresponding unit ***, it decreased with an increase in the incident angle and scattering albedo. These results provide a reference for addressing the low efficiency and thermal damage caused by traditional solar collectors at high temperatures.

关键词： direct absorption solar collector radiative heat transfer Monte Carlo

Rethinking multi-spatial information for transferable adversarial attacks on speaker recognition systems

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CAAI Transactions on Intelligence Technology 2024年第3期9卷 620-631页

作者： Junjian Zhang Hao tan Le Wang Yaguan Qian Zhaoquan Gu Guangzhou University GuangzhouChina Department of New Networks Peng Cheng LaboratoryShenzhenChina Harbin Institute of Technology(Shenzhen) ShenzhenChina Zhejiang University of Science and Technology HangzhouChina

Adversarial attacks have been posing significant security concerns to intelligent systems,such as speaker recognition systems(SRSs).Most attacks assume the neural networks in the systems are known beforehand,while black-box attacks are proposed without such information to meet practical *** black-box attacks improve trans-ferability by integrating multiple models or training on multiple datasets,but these methods are *** by the optimisation strategy with spatial information on the perturbed paths and samples,we propose a Dual Spatial Momentum Iterative Fast Gradient Sign Method(DS-MI-FGSM)to improve the transferability of black-box at-tacks against ***,DS-MI-FGSM only needs a single data and one model as the input;by extending to the data and model neighbouring spaces,it generates adver-sarial examples against the integrating *** reduce the risk of overfitting,DS-MI-FGSM also introduces gradient masking to improve *** authors conduct extensive experiments regarding the speaker recognition task,and the results demonstrate the effectiveness of their method,which can achieve up to 92%attack success rate on the victim model in black-box scenarios with only one known model.

关键词： speaker recognition spoofing attacks

Emergence of machine language: towards symbolic intelligence with neural networks

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National Science Review 2024年第4期11卷 27-30页

作者： Yuqi Wang Xu-Yao Zhang Cheng-Lin Liu Tieniu tan Zhaoxiang Zhang State Key Laboratory of Multimodal Artificial Intelligence Systems Institute of AutomationChinese Academy of Sciences

Representation learning is a core issue in artificial intelligence (AI). Currently,there exists a disparity in the choice of representation between humans and machines. Humans rely on discrete language for communicati...

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Temporal and spatial regulation of biomimetic vascularization in 3D-printed skeletal muscles

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Bio-Design and Manufacturing 2024年第5期7卷 597-610页

作者： Minxuan Jia Tingting Fan tan Jia Xin Liu Heng Liu Qi Gu Key Laboratory of Organ Regeneration and Reconstruction State Key Laboratory of Membrane BiologyInstitute of ZoologyChinese Academy of SciencesBeijing 100101China Beijing Institute for Stem Cell and Regenerative Medicine Beijing 100101China University of Chinese Academy of Sciences Beijing 100049China State Key Laboratory of Stem Cell and Reproductive Biology Institute of ZoologyChinese Academy of SciencesBeijing 100101China Department of Orthopaedics Beijing Jishuitan HospitalCapital Medical UniversityBeijing 100035China

In the intricate skeletal muscle tissue,the symbiotic relationship between myotubes and their supporting vasculature is pivotal in delivering essential oxygen and *** study explored the complex interplay between skeletal muscle and endothelial cells in the vascularization ofmuscle *** harnessing the capabilities of three-dimensional(3D)bioprinting and modeling,we developed a novel approach involving the co-construction of endothelial and muscle cells,followed by their subsequent *** findings highlight the importance of the interaction dynamics between these two cell ***,introducing endothelial cells during the advanced phases of muscle differentiation enhanced myotube ***,it stimulated the development of the vascular network,paving the way for the early stages of vascularized skeletal muscle *** methodology proposed in this study indicates the potential for constructing large-scale,physiologically aligned skeletal ***,it highlights the need for exploring the delicate equilibrium and mutual interactions between muscle and endothelial *** on the multicell-type interaction model,we can predict promising pathways for constructing even more intricate tissues or organs.

关键词： Skeletal muscle Vascularization 3D bioprinting Cell interaction

Observation and Analysis of VLF Nocturnal Multimode Interference Phenomenon based on Waveguide Mode Theory

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Research in Astronomy and Astrophysics 2024年第1期24卷 78-86页

作者： sai Yang You-Tian Niu Zhe Wang Xiu-Kun Zhao Bei Li Yu-Ling Ding Ge-Ge Zhao An-Qi Zhang College of Electronic and Electrical Engineering Henan Normal UniversityXinxiang 453007China Academician Workstation of Electromagnetic Wave Engineering of Henan Province Xinxiang 453007China Key Laboratory of Optoelectronic Sensing Integrated Application of Henan Province Xinxiang 453007China Engineering Laboratory of Intelligent Additive Manufacturing of Henan Province Xinxiang 453007China

Very low frequency(VLF)signals are propagated between the *** interference will cause the phase to show oscillatory changes with distance while propagating at night,leading to abnormalities in the received VLF *** study uses the VLF signal received in Qingdao City,Shandong Province,from the Russian Alpha navigation system to explore the multimode interference problem of VLF signal *** characteristics of the effect of multimode interference phenomena on the phase are analyzed according to the variation of the phase of the VLF ***,the phase of VLF signals will also be affected by the X-ray and energetic particles that are released during the eruption of solar flares,therefore the two phenomena are studied in this *** is concluded that the X-ray will not affect the phase of VLF signals at night,but the energetic particles will affect the phase change,and the influence of energetic particles should be excluded in the study of multimode interference *** VLF signals for navigation positioning in degraded or unavailable GPS conditions is of great practical significance for VLF navigation systems as it can avoid the influence of multimode interference and improve positioning accuracy.

关键词： waves methods:data analysis Sun:flares Sun:X-rays gamma-rays

Compound events of heatwave and dust storm in the Taklamakan Desert

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Science China Earth Sciences 2024年第7期67卷 2073-2083页

作者： Yuzhi LIU Jianping HUANG Ziyuan tan Chenglong ZHOU Dan LI Yongkun XIE Key Laboratory for Semi-Arid Climate Change of the Ministry of Education Lanzhou UniversityLanzhou 730000China Collaborative Innovation Center for Western Ecological Safety Lanzhou UniversityLanzhou 730000China Taklamakan National Station of Observation and Research for Desert Meteorology in Xinjiang Urumqi 830002China

Taklamakan Desert(TD)has been characterized by numerous heatwaves and dust storms,leading to negative effects on societies and ecosystems at regional and global ***,the association between heatwaves and dust storms is poorly *** this study,we describe the association between heatwaves and dust events and propose a mechanism for such compound events in the *** results show that,from 1993 to 2022,the frequency and intensity of heatwaves in the TD have increased at a rate of 0.21 days year^(-1)and 0.02℃ year^(-1),*** than 40% of heatwaves existed with dust events,which significantly lagged behind ***,the higher the air temperature,the hotter and drier the soil,leading to more dust emissions in the *** high-occurrence heatwave years,a large-scale wave train of“cyclone-anticyclone-cyclone”in the northwest-southeast direction was found,with the anticyclone of which hovered over the TD *** anomalous anticyclones favored the formation and maintenance of heatwaves,and subsequent anomalous cyclones in the wave train triggered strong dust events followed by *** climate warming,the compound events of heatwave and dust storm are becoming bigger hazards threatening the socioeconomic and ecological security in the TD,the profound study of which is critical to understanding regional extreme responses.

关键词： Heatwave Dust storm Compound events Taklamakan Desert