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Defects in the grain interiors of 3 mol%yttria-stabilized tetragonal zirconia polycrystal ceramics with 0.25 wt%alumina

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Journal of Advanced Ceramics 2024年第4期13卷 469-477页

作者： Yan xiong Lian Luo Yao Cheng zhi Liu qi Liu Weimin Wang Wei Ji School of Materials&Chemical Engineering Hubei Province Key Laboratory of Green Materials for Light IndustryHubei University of TechnologyWuhan 430068China Fujian Institute of Research on the Structure of Mater Chinese Academy of SciencesFuzhou 350002China Jiangxi Provincial Engineering Research Center for Multifunction Zirconia Materials Jiangxi Size Materials Co.Ltd.Jiujiang 332500China State Key Laboratory of Advance Technology for Materials Synthesis and Processing Wuhan University of TechnologyWuhan 430070China

The presence of high-density defects is rarely observed in bulk 3 mol%yttria-stabilized tetragonal zirconia polycrystal(3Y-TZP)ceramics obtained through conventional pressureless sintering.In the present work,fine-grained dense 147 nm 3Y-TZP ceramics were prepared by pressureless sintering of commercial 0.25 wt%alumina-doped zirconia powders at 1300℃.A novel discovery was reported in which large amounts of defects were present in the grain interiors of the sample.The phenomenon was further examined using three types of powder samples,and the reasons for defect formation were investigated by microstructural characterization using high-resolution transmission electron microscopy(HRTEM)analysis and Rietveld refinement.The results confirmed the essential dependence of the defect formation on the alumina addition.The authors attributed the defect formation to the significant difference in ionic radii of the solvent and solute during the dissolution of alumina into the zirconia lattice.The sintering kinetics were proposed to be enhanced by the presence of substantial defects,which consequently favored the low-temperature sintering of the alumina-doped zirconia ceramics.

关键词： 3 mol%yttria-stabilized tetragonal zirconia polycrystal(3Y-TzP)ceramics alumina addition microstructure defect

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Deciphering and integrating invariants for neural operator learning with various physical mechanisms

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National Science Review 2024年第4期11卷 111-122页

作者： Rui Zhang qi Meng zhi-Ming Ma Academy of Mathematics and Systems Science Chinese Academy of Sciences(CAS) Microsoft Research

Neural operators have been explored as surrogate models for simulating physical systems to overcome the limitations of traditional partial differential equation(PDE) solvers. However, most existing operator learning methods assume that the data originate from a single physical mechanism, limiting their applicability and performance in more realistic scenarios. To this end, we propose the physical invariant attention neural operator(PIANO) to decipher and integrate the physical invariants for operator learning from the PDE series with various physical mechanisms. PIANO employs self-supervised learning to extract physical knowledge and attention mechanisms to integrate them into dynamic convolutional layers.Compared to existing techniques, PIANO can reduce the relative error by 13.6%–82.2% on PDE forecasting tasks across varying coefficients, forces or boundary conditions. Additionally, varied downstream tasks reveal that the PI embeddings deciphered by PIANO align well with the underlying invariants in the PDE systems, verifying the physical significance of PIANO.

关键词： neural operator PDE solver contrastive learning physical invariants

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Effect of stress-relief annealing on thermal fatigue cracks for die-casting die steels

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Journal of Iron and Steel Research(International) 2024年第5期31卷 1164-1176页

作者： zhi-xiong Bai Xiao-chun Wu School of Materials Science and Engineering Shanghai UniversityShanghai200444China

The effect of stress-relief annealing at different stages of thermal fatigue tests on crack growth was investigated using a self-built thermal cycle setup.The results showed that annealing could limit crack expansion effectively.It reduced dislocation density and released the accumulation of residual stress.In addition,the strain accumulation in carbides was reduced by this process.It was also found that double annealing was even more effective at inhibiting crack expansion compared to single stress-relief annealing.After 1000 cycles,the maximum crack length was reduced by 31.1%and 45.2%for the samples after using the optimal single and double annealing processes,respectively.For single stress-relief annealing,earlier annealing provides more benefit in delaying crack expansion.However,effective double stress-relief annealing requires a suitable time interval between the annealing steps.Besides,after 800 cycles,surface hardness decreased significantly accompanied by an increase in the size and number of carbides,and cracks expanded predominantly along grain boundaries.

关键词： Thermal fatigue Steel Carbide Stress-relief annealing Dislocation Residual stress

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Asperuloside Promotes Apoptosis of Cervical Cancer Cells through Endoplasmic Reticulum Stress-Mitochondrial Pathway

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Chinese Journal of Integrative Medicine 2024年第1期30卷 34-41页

作者： qi zhi-min WANG Xia LIU Xia ZHAO Juan Medical Examination Center Hebei Province Hospital of Chinese MedicineShijiazhuang(050011)China Department of Gynaecology and Obstetrics Hebei Province Hospital of Chinese MedicineShijiazhuang(050011)China Experimental Center for Teaching Hebei Medical UniversityShijiazhuang(050017)China

Objective: To investigate the effects of asperuloside on cervical cancer based on endoplasmic reticulum(ER) stress and mitochondrial pathway. Methods: Different doses(12.5–800 μg/mL) of asperuloside were used to treat cervical cancer cell lines Hela and CaSki to calculate the half maximal inhibitory concentration(IC_(50)) of asperuloside. The cell proliferation was analyzed by clone formation assay. Cell apoptosis, intracellular reactive oxygen species(ROS) and mitochondrial membrane potential were determined by flow cytometry. The protein expressions of cleaved-caspase-3, Bcl-2, Bax, Cyt-c, cleaved-caspase-4 and glucose-regulated protein 78(GRP78) were analyzed by Western blot. And the inhibitor of ER stress, 4-phenyl butyric acid(4-PBA) was used to treat cervical cancer cells to further verify the role of ER stress in the apoptosis of cervical cancer cells induced by asperuloside. Results: Asperuloside of 325, 650, and 1300 μg/mL significantly inhibited the proliferation and promoted apoptosis of Hela and CaSki cells(P<0.01). All doses of asperuloside significantly increased intracellular ROS levels, reduced mitochondrial membrane potential, significantly reduced Bcl-2 protein expression level, and increased Bax, Cyt-c, GRP78 and cleaved-caspase-4 expressions(P<0.01). In addition, 10 mmol/L 4-PBA treatment significantly promoted cell proliferation and reduced apoptosis(P<0.05), and 650 μg/mL asperuloside could reverse 4-PBA-induced increased cell proliferation, decreased apoptosis and cleaved-caspase-3,-4 and GRP78 protein expressions(P<0.05). Conclusion: Our study revealed the role of asperuloside in cervical cancer, suggesting that asperuloside promotes apoptosis of cervical cancer cells through ER stress-mitochondrial pathway.

关键词： asperuloside Chinese medicine cervical cancer endoplasmic reticulum stress mitochondrial damage apoptosis

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Cosmological Constraints on Neutrino Masses in Light of JWST Red and Massive Candidate Galaxies

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Research in Astronomy and Astrophysics 2024年第4期24卷 7-12页

作者： Jian-qi Liu zhi-qi Huang Yan Su School of Physics and Astronomy Sun Yat-sen UniversityZhuhai 519082China CSST Science Center for the Guangdong-Hong Kong-Macao Greater Bay Area Zhuhai 519082China

The overabundance of the red and massive candidate galaxies observed by the James Webb Space Telescope(JWST)implies efficient structure formation or large star formation efficiency at high redshift z~10.In the scenario of a low or moderate star formation efficiency,because massive neutrinos tend to suppress the growth of structure of the universe,the JWST observation tightens the upper bound of the neutrino masses.Assuming A cold dark matter cosmology and a star formation efficiency∈[0.05,0.3](flat prior),we perform joint analyses of Planck+JWST and Planck+BAO+JWST,and obtain improved constraints∑m_(ν)<0.196 eV and ∑m_(ν)+<0.111 eV at 95% confidence level,respectively.Based on the above assumptions,the inverted mass ordering,which implies ∑m_(ν)≥0.1 eV,is excluded by Planck+BAO+JWST at 92.7% confidence level.

关键词： (cosmology:)cosmological parameters galaxies:abundances galaxies:formation neutrinos

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Extracellular vesicles derived from mesenchymal stem cells mediate extracellular matrix remodeling in osteoarthritis through the transport of microRNA-29a

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World Journal of Stem Cells 2024年第2期16卷 191-206页

作者： Fan Yang Wan-qi xiong Chen-zhi Li Ming-Jian Wu Xiu-zhi Zhang Chun-Xiao Ran Zhen-Hao Li Yan Cui Bao-Yi Liu De-Wei Zhao Department of Orthopedics Affiliated Zhongshan Hospital of Dalian UniversityDalian 116001Liaoning ProvinceChina

BACKGROUND Knee osteoarthritis(KOA)is a common orthopedic condition with an uncertain etiology,possibly involving genetics and biomechanics.Factors like changes in chondrocyte microenvironment,oxidative stress,inflammation,and immune responses affect KOA development.Early-stage treatment options primarily target symptom relief.Mesenchymal stem cells(MSCs)show promise for treatment,despite challenges.Recent research highlights microRNAs(miRNAs)within MSC-released extracellular vesicles that can potentially promote cartilage regeneration and hinder KOA progression.This suggests exosomes(Exos)as a promising avenue for future treatment.While these findings emphasize the need for effective KOA progression management,further safety and efficacy validation for Exos is essential.AIM To explore miR-29a’s role in KOA,we’ll create miR-29a-loaded vesicles,testing for early treatment in rat models.METHODS Extraction of bone marrow MSC-derived extracellular vesicles,preparation of engineered vesicles loaded with miR-29a using ultrasonication,and identification using quantitative reverse transcription polymerase chain reaction;after establi-shing a rat model of KOA,rats were randomly divided into three groups:Blank control group injected with saline,normal extracellular vesicle group injected with normal extracellular vesicle suspension,and engineered extrace-llular vesicle group injected with engineered extracellular vesicle suspension.The three groups evaluation,histological detection,and immunohistochemical detection to compare and evaluate the progress of various forms of arthritis.RESULTS General behavioral observation results showed that the extracellular vesicle group and engineered extracellular vesicle group had better performance in all four indicators of pain,gait,joint mobility,and swelling compared to the blank control group.Additionally,the engineered extracellular vesicle group had better pain relief at 4 wk and better knee joint mobility at 8 wk compared to the normal extracellular vesicle group.Imaging examinat

关键词： Exosomes Osteoarthritis Mesenchymal stem cells MicroRNA-29a Intra-articular injection

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Transient stimulated Raman scattering spectroscopy and imaging

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Light(Science & Applications) 2024年第4期13卷 654-663页

作者： qiaozhi Yu Zhengjian Yao Jiaqi Zhou Wenhao Yu Chenjie Zhuang Yafeng qi Hanqing xiong National Biomedical Imaging Center College of Future TechnologyPeking UniversityBeijing 100871China Biomedical Engineering Department College of Future TechnologyPeking UniversityBeijing 100871China

Stimulated Raman scattering(SRS)has been developed as an essential quantitative contrast for chemical imaging in recent years.However,while spectral lines near the natural linewidth limit can be routinely achieved by state-of-the-art spontaneous Raman microscopes,spectral broadening is inevitable for current mainstream SRS imaging methods.This is because those SRS signals are all measured in the frequency domain.There is a compromise between sensitivity and spectral resolution:as the nonlinear process benefits from pulsed excitations,the fundamental time-energy uncertainty limits the spectral resolution.Besides,the spectral range and acquisition speed are mutually restricted.Here we report transient stimulated Raman scattering(T-SRS),an alternative time-domain strategy that bypasses all these fundamental conjugations.T-SRS is achieved by quantum coherence manipulation:we encode the vibrational oscillations in the stimulated Raman loss(SRL)signal by femtosecond pulse-pair sequence excited vibrational wave packet interference.The Raman spectrum was then achieved by Fourier transform of the time-domain SRL signal.Since all Raman modes are impulsively and simultaneously excited,T-SRS features the natural-linewidth-limit spectral line shapes,laser-bandwidth-determined spectral range,and improved sensitivity.With~150-fs laser pulses,we boost the sensitivity of typical Raman modes to the sub-mM level.With all-plane-mirror high-speed time-delay scanning,we further demonstrated hyperspectral SRS imaging of live-cell metabolism and high-density multiplexed imaging with the natural-linewidth-limit spectral resolution.T-SRS shall find valuable applications for advanced Raman imaging.

关键词： scattering excited mutually

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Thoracic spinal cord injury and paraplegia caused by intradural cement leakage after percutaneous kyphoplasty: A case report

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World Journal of Clinical Cases 2024年第10期12卷 1837-1843页

作者： Zi Mao zhi-Hong xiong Jun-Feng Li Department of Pain Management The Affiliated Hospital of Yunnan UniversityKunming 650000Yunnan ProvinceChina Department of Medical Administration The Affiliated Hospital of Yunnan UniversityKunming 650000Yunnan ProvinceChina

BACKGROUND Percutaneous kyphoplasty(PKP)is a pivotal intervention for osteoporotic fractures,pathological vertebral compression fractures,and vertebral bone tumors.Despite its efficacy,the procedure presents challenges,notably complications arising from intradural cement leakage.Timely and accurate diagnosis,coupled with emergent intervention is imperative to improve patient prognosis.This case report illuminates the intricacies and potential complications associated with PKP,emphasizing the critical need for vigilant monitoring,prompt diagnosis,and immediate intervention to mitigate adverse outcomes.CASE SUMMARY A 58-year-old male patient,experiencing a T7 osteoporosis-related pathological compression fracture,underwent PKP at a local hospital.Two weeks postprocedure,the patient developed paraplegic and dysuric symptoms,necessitating emergency decompression surgery.Gradual improvement was achieved,marked by the restoration of muscle strength,sensation,and mobility.CONCLUSION PKP Intradural cement leakage following PKP is unusual and potentially fatal.Prompt imaging examinations,urgent evaluation,and the decompression surgery are essential,which help alleviate symptoms associated with spinal damage,markedly improving the overall prognosis.

关键词： Percutaneous kyphoplasty Intradural cement leakage Complication Decompression surgery Case report

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Understanding the spatial interaction of ultrasounds based on three-dimensional dual-frequency ultrasonic field numerical simulation

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China Foundry 2024年第1期21卷 29-43页

作者： Zhao-yang Yin qi-chi Le Yan-chao Jiang Da-zhi Zhao qi-yu Liao qi Zou Key Lab of Electromagnetic Processing of Materials Ministry of EducationNortheastern UniversityShenyang 110819China School of Materials Science and Engineering Northeastern UniversityShenyang 110819China

A transient 3D model was established to investigate the effect of spatial interaction of ultrasounds on the dual-frequency ultrasonic field in magnesium alloy melt.The effects of insertion depth and tip shape of the ultrasonic rods,input pressures and their ratio on the acoustic field distribution were discussed in detail.Additionally,the spacing,angle,and insertion depth of two ultrasonic rods significantly affect the interaction between distinct ultrasounds.As a result,various acoustic pressure distributions and cavitation regions are obtained.The spherical rods mitigate the longitudinal and transversal attenuation of acoustic pressure and expand the cavitation volume by 53.7%and 31.7%,respectively,compared to the plate and conical rods.Increasing the input pressure will enlarge the cavitation region but has no effect on the acoustic pressure distribution pattern.The acoustic pressure ratio significantly affects the pressure distribution and the cavitation region,and the best cavitation effect is obtained at the ratio of 2:1(P15:P20).

关键词： dual-frequency ultrasonic numerical model acoustic pressure spatial interaction magnesium alloy

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High-Order Two-Scale Asymptotic Paradigm for the Elastodynamic Homogenization of Periodic Composites

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Acta Mechanica Solida Sinica 2024年第1期37卷 124-138页

作者： Wei-zhi Luo Mu He Liang Xia qi-Chang He State Key Laboratory of Intelligent Manufacturing Equipment and Technology Huazhong University of Science and TechnologyWuhan 430074China Laboratoire Modélisation et Simulation Multi-Echelle MSME UMR 8208 CNRSUniversite Gustave Eiffel77454 Marne-la-ValléeFrance

The classical two-scale asymptotic paradigm provides macroscopic and microscopic analyses for the elastodynamic homogenization of periodic composites based on the spatial or/and temporal variable,which offers an approximate framework for the asymptotic homogenization analysis of the motion equation.However,in this framework,the growing complexity of the homogenization formulation gradually becomes an obstacle as the asymptotic order increases.In such a context,a compact,fast,and accurate asymptotic paradigm is developed.This work reviews the high-order spatial two-scale asymptotic paradigm with the effective displacement field representation and optimizes the implementation by symmetrizing the tensor to be determined.Remarkably,the modified implementation gets rid of the excessive memory consumption required for computing the high-order tensor,which is demonstrated by representative one-and two-dimensional cases.The numerical results show that(1)the contrast of the material parameters between media in composites directly affects the convergence rate of the asymptotic results for the homogenization of periodic composites,(2)the convergence error of the asymptotic results mainly comes from the truncation error of the modified asymptotic homogenized motion equation,and(3)the excessive norm of the normalized wavenumber vector in the two-dimensional inclusion case may lead to a non-convergence of the asymptotic results.

关键词： Composites Homogenization Asymptotic analysis Dynamics Dispersion

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