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Capturing metal clusters at the strong-interaction region to reverse Ostwald ripening

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Science China Materials 2024年第4期67卷 1363-1364页

作者： Shuheng Tian ding Ma Beijing National Laboratory for Molecular Sciences New Cornerstone Science LaboratoryCollege of Chemistry and Molecular EngineeringPeking UniversityBeijing 100871China

High-temperature interactions induce sintering of metal nanoparticles(NPs) on heterogeneous catalyst surfaces, leading to reduced surface area and active site loss through Ostwald ripening [1]. This irreversible deactivation necessitates costly catalyst replacement, notably impacting metals like copper in hydrogenation and reforming reactions [2].

关键词： catalyst reforming irreversible

A newly unraveled 13.6-year oscillation from GPS displacements and its potential implications for the dynamic reference frame

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Science China Earth Sciences 2024年第10期67卷 3204-3212页

作者： Hao ding Weiping JIANG School of Geodesy and Geomatics Hubei Luojia LaboratoryWuhan UniversityWuhan 430079China GNSS Research Center Wuhan UniversityWuhan 430079China

Numerous practical geodetic and geophysical applications necessitate precise measurements of GNSS displacements at the millimeter or sub-millimeter level. To attain such precision, it is imperative to identify and analyze the unidentified decadal signals inherent in the GPS displacements. In this research, we employ the optimal sequence estimation method to effectively detect an about 13.6-year oscillational signal with an excited amplitude of 3.6±1.2 mm in the U-components of the GPS displacements. It is noteworthy that this signal demonstrates a consistent spatial pattern characterized by the spherical harmonic Y_(2,-2). We conduct a comparative analysis with the 13.6-year oscillation observed in length-of-day variations(and geomagnetic records), finding that they are in reverse phase. After eliminating the Earth's external excitation sources through the utilization of two distinct in-situ hydrological records, we suggest that the 13.6-year GPS signal may come from the internal motions within the Earth. However, the specific excitation source and the detailed physical mechanism remain uncertain. Additionally, we develop a mathematical displacement model to explain the 13.6-year signal. Our findings indicate that this signal can result in displacements of up to 1.37 mm and velocity effects of 0.63 mm/yr(for U-component) at maximum. These results underscore the necessity of incorporating this 13.6-year signal into the construction and maintenance of a dynamic reference frame at the millimeter level.

关键词： GPS displacements Decadal changes 13.6-year oscillation Displacement model Dynamic reference frame

Towards human-leveled vision systems

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Science China(Technological Sciences) 2024年第8期67卷 2331-2349页

作者： ding JianHao HUANG TieJun State Key Laboratory of Multimedia Information Processing School of Computer SciencePeking UniversityBeijing 100871China

The human visual system is a complex and interconnected network comprising billions of neurons. It plays an essential role in translating environmental light stimuli into information that guides and shapes human perception and action. Research on the visual system aims to uncover the underlying neural structure principles of human visual perception and their possible ***, there are two main approaches: biological system analysis and simulation, artificial intelligence models based on deep learning. Here we aim to discuss the two approaches to human-level vision systems. Deep learning has significantly impacted the field of vision with achievements in representation, modeling, and hardware design. However, there is still a significant gap between deep learning models and the human visual system in terms of scalability, transferability, and sustainability. The progress of the biological visual system can help fill the gap by further understanding the properties and functions of different components of the system. We take the efforts of reconstructing the retina as an example to illustrate that even if we are unable to replicate the visual system on a computer right now, we can still learn a lot by combining existing research outcomes in neuroscience. At the end of the paper, we suggest tracing back to gradually build visual systems from the computational counterpart of biological structures to achieve a human-level vision system in the future.

关键词： human-leveled vision system deep learning biological visual system

New advances in the study of Tethyan Geodynamic System

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Science China Earth Sciences 2024年第3期67卷 874-878页

作者： Lin ding State Key Laboratory of Tibetan Plateau Earth System Science(LATPES) Institute of Tibetan Plateau ResearchChinese Academy of SciencesBeijing 100101China

Tethyan Ocean was initially proposed by Austrian geologist Eduard Suess in 1893. The study of the Tethyan evolution by European geologists has led to the development of modern geology, but not to the establishment of plate tectonics theory(Trümpy, 2001). With the progress in various studies, the concept of Tethys has evolved from a Mesozoic ocean into three long-term evolving oceans:Proto-Tethys, Paleo-Tethys, and Neo-Tethys (Figure 1), and their life cycles cover the entire Phanerozoic era (Wu et al., 2020).

关键词： geology Mesozoic ocean

CALD1 facilitates epithelial-mesenchymal transition progression in gastric cancer cells by modulating the PI3K-Akt pathway

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World Journal of Gastrointestinal Oncology 2024年第3期16卷 1029-1045页

作者： Wen-Qian Ma Ming-Chang Miao Ping-An ding bi-Bo Tan Wen-Bo Liu Shuo Guo Li-Mian Er Zhi-Dong Zhang Qun Zhao Department of Endoscopy The Fourth Hospital of Hebei Medical UniversityShijiazhuang 050011Hebei ProvinceChina Hebei Key Laboratory of Precision Diagnosis and Comprehensive Treatment of Gastric Cancer Shijiazhuang 050011Hebei ProvinceChina Department of Radiotherapy The Fourth Hospital of Hebei Medical UniversityShijiazhuang 050011Hebei ProvinceChina The Third Department of Surgery The Fourth Hospital of Hebei Medical UniversityShijiazhuang 050011Hebei ProvinceChina

BACKGROUND CALD1 has been discovered to be abnormally expressed in a variety of malignant tumors,including gastric cancer(GC),and is associated with tumor progression and immune infiltration;however,the roles and mechanisms of CALD1 in epithe-lial-mesenchymal transition(EMT)in GC are *** To investigate the role and mechanism of CALD1 in GC progression,invasion,and *** In this study,the relationship between CALD1 and GC,as well as the possible network regulatory mechanisms of CALD1,was investigated by bioinformatics and validated by ***1-siRNA was synthesized and used to trans-fect GC *** activity was measured using the CCK-8 method,cell migration and invasive ability were measured using wound healing assay and Transwell assay,and the expression levels of relevant genes and proteins in each group of cells were measured using qRT-PCR and Western blot.A GC cell xenograft model RESULTS bioinformatics results showed that CALD1 was highly expressed in GC tissues,and CALD1 was significantly higher in EMT-type GC tissues than in tissues of other types of *** prognosis of patients with high expression of CALD1 was worse than that of patients with low expression,and a prognostic model was constructed and *** experimental results were consistent with the results of the bioinformatics *** expression level of CALD1 in GC cell lines was all higher than that in gastric epithelial cell line GES-1,with the strongest expression found in AGS and MKN45 *** activity was significantly reduced after CALD1-siRNA trans-fection of AGS and MKN45 *** ability of AGS and MKN45 cells to migrate and invade was reduced after CALD1-siRNA transfection,and the related mRNA and protein expression was *** to bioinfor-matics findings in GC samples,the CALD1 gene was significantly associated with the expression of members of the PI3K-AKT-mTOR signaling pathway as well as the EMT signaling pathway,and was closely rel

关键词： Gastric tumor CALD1 Epithelial-mesenchymal transition Gene disruption Invasion Migration bioinformatics

Equivalent linear model for seismic damage evaluation of single-degree-of-freedom systems representing reinforced concrete structures considering cyclic degradation behavior

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Earthquake Engineering and Engineering Vibration 2024年第3期23卷 637-648页

作者： Lulu Yan ding-Hao Yu Research Center for Geotechnical and Structural Engineering Technology of Liaoning Province Dalian UniversityDalian116622China State Key Laboratory of Coastal and Offshore Engineering Dalian University of TechnologyDalian 116024China

In this study,a novel equivalent damping ratio model that is suitable for reinforced concrete(RC)structures considering cyclic degradation behavior is developed,and a new equivalent linearization analysis method for implementing the proposed equivalent damping ratio model for use in seismic damage evaluation is *** this end,Ibarra’s peak-oriented model,which incorporates an energy-based degradation rule,is selected for representing hysteretic behavior of RC structure,and the optimized equivalent damping for predicting the maximum displacement response is presented by using the empirical method,in which the effect of cyclic degradation is ***,the relationship between the hysteretic energy dissipation of the inelastic system and the elastic strain energy of the equivalent linear system is established so that the proposed equivalent linear system can be directly integrated with the Park-Ang seismic model to implement seismic damage *** to the simplicity of the equivalent linearization method,the proposed method provides an efficient and reliable way of obtaining comprehensive insight into the seismic performance of RC *** verification demonstrates the validity of the proposed method.

关键词： degrading system equivalent linear system equivalent damping seismic damage RC structures

A PDGFRβ-targeting nanodrill system for pancreatic fibrosis therapy

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Chinese Chemical Letters 2024年第10期35卷 353-359页

作者： Han Han bi-Te Chen Jia-Rong ding Jin-Ming Si Tian-jiao Zhou Yi Wang Lei Xing Hu-Lin Jjiang State Key Laboratory of Natural Medicines Department of PharmaceuticsChina Pharmaceutical UniversityNanjing 210009China College of Pharmacy .Yanbian UniversityYanji 133002China Department of Nephrology Changhai HospitalNaval Medical UniversityShanghai 200433China

Activated pancreatic stellate cells(PSCs)are the main source of collagen layer deposition and the key target in pancreatic ***,no effective treatment specific to pancreatic fibrosis clinically,owing to the drug accumulation blocked by the collagen barrier and thus it is difficult to inhibit activated PSCs ***,a PSCs-targeting nano-system based on“nanodrill”strategy(LA-PC)was designed to enhance the accumulation of all-trans retinoic acid(ATRA)in PSCs,relying on the platelet-derived growth factor receptor beta(PDGFRβ)-targeting peptide(p PB:C*SRNLIDC*)and collagenase(Col).After being injected into fibrotic mice via tail vein,the Col modified on LA-PC can remove the excess collagen layer,and the drug delivery efficiency through pPB targeting peptide was more than 5 times higher than that of free ATRA,as well as the degree of fibrosis significantly ***,this nano-system effectively inhibited platelet-derived growth factor subunit B(PDGF-BB)/PDGFRβaxis on PSCs via a down-regulated extracellular signal-regulated protein kinase(ERK)pathway,and accordingly reduced the level of ***,the smart platform provided a promising strategy for the treatment of pancreatic fibrosis to achieve the precise regulation of PSCs.

关键词： Pancreatic fibrosis Pancreatic stellate cells Liposome PDGFRβ pPB peptide

Catalysis by subsurface metal atoms in Al(001) through electron transfer

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National Science Review 2024年第4期11卷 12-13页

作者： Bo Sun ding Ma Beijing National Laboratory for Molecular Science New Cornerstone Science Laboratory College of Chemistry and Molecular Engineering Peking University

Heterogeneous catalysis plays a crucial role in the chemical industry, which has evolved from the investigation of chemisorption to an electronic structure[1]. Diverse strategies, such as alloying,doping, and confining, have been applied to enhance the catalytic properties of active sites through electronic modulation. The electron transfer between active sites and substrates profoundly influences catalytic activity [2].

关键词：

Constraint on the focal mechanism of the 2011 Tohoku earthquake from the radial modes

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Geodesy and Geodynamics 2024年第1期15卷 27-32页

作者： Weikun Chen Hao ding School of Geodesy and Geomatics Hubei LuoJia LaboratoryWuhan UniversityWuhan 430079China

Different from other normal modes of the Earth’s free oscillation that depend on all the six components(M_(rr),M_(tt),M_(pp),M_(rt),M_(rp),and M_(tp))of the centroid moment tensor,the amplitudes of the radial modes depend on the M_(rr)component(e.g.,scalar moment(M_(0)),dip(δ),and slip(λ))and hypocenter depth of the focal mechanism,and hence can be easily used to constrain these parameters of the focal *** this study,we use the superconducting gravimeter(SG)records after the 2011 Tohoku earthquake to analyze the radial modes_(0)S_(0)and_(1)S_(0).Based on the solutions of the focal mechanism provided by the GCMT and USGS,we can obtain the theoretical amplitudes of these two radial *** the theoretical amplitudes with the observation amplitudes,it is found that there are obvious differences between the former and the latter,which means that the GCMT and USGS focal mechanisms cannot well represent the real focal mechanism of the 2011 *** the GCMT solution as a reference and changing the depth and the three parameters of the M_(rr)moment,the scalar moment(M_(0))and the dip(δ)have significant influences,but the effects of the slip(λ)and the depth are *** comparisons,we provide a new constraint(M_(0)=5.8±0.09×10^(22)N·m,δ=10.1±0.08°,λ=88°,and depth=20 km)for the focal mechanism of the 2011 *** addition,we further determine the center frequency(1.631567±2.6e^(-6)mHz)and quality factor(2046.4±50.1)of the_(1)S_(0)mode.

关键词： Focal mechanism Radial modes Gravity observation