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Remarks on two theorems of Qi-keng Lu

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Science China Mathematics 2008年第4期51卷 773-776页

作者： CHEUNG Wing-sum WONG Bun Department of Mathematics University of Hong Kong Department of Mathematics University of California

Two alternate arguments in the framework of intrinsic metrics and measures respectively of part of the proof of a famous theorem due to Qi-keng Lu on Bergman metric with constant negative holomorphic sectional curvature are presented.A relationship between the Lu constant and the holo- morphic sectional curvature of the Bergman metric is *** recent progress of the Yau’s porblem on the characterization of domain of holomorphy on which the Bergman metric is k(?)hler-Einstein is described.

关键词： Bergman metric holomorphic sectional curvature intrinsic metrics and measures Qi-keng Lu theorem 32F45 32Q05 32W20

NECAB family of neuronal calcium-binding proteins in health and disease

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Neural Regeneration Research 2025年第5期20卷 1236-1243页

作者： Diones Bueno Michael k.E.Schafer Sudena Wang Michael J.Schmeisser Axel Methner Institute for Molecular Medicine University Medical Center of the Johannes Gutenberg-UniversityMainzGermany Department of Anesthesiology University Medical Center of the Johannes Gutenberg-UniversityMainzGermany Institute of Anatomy University Medical Center of the Johannes Gutenberg-UniversityMainzGermany

The N-terminal EF-hand calcium-binding proteins 1–3(NECAB1–3) constitute a family of predominantly neuronal proteins characterized by the presence of at least one EF-hand calcium-binding domain and a functionally less well characterized C-terminal antibiotic biosynthesis monooxygenase domain. All three family members were initially discovered due to their interactions with other proteins. NECAB1 associates with synaptotagmin-1, a critical neuronal protein involved in membrane trafficking and synaptic vesicle exocytosis. NECAB2 interacts with predominantly striatal G-protein-coupled receptors, while NECAB3 partners with amyloid-β A4 precursor protein-binding family A members 2 and 3, key regulators of amyloid-β production. This demonstrates the capacity of the family for interactions with various classes of proteins. NECAB proteins exhibit distinct subcellular localizations: NECAB1 is found in the nucleus and cytosol, NECAB2 resides in endosomes and the plasma membrane, and NECAB3 is present in the endoplasmic reticulum and Golgi apparatus. The antibiotic biosynthesis monooxygenase domain, an evolutionarily ancient component, is akin to atypical heme oxygenases in prokaryotes but is not wellcharacterized in vertebrates. Prokaryotic antibiotic biosynthesis monooxygenase domains typically form dimers, suggesting that calcium-mediated conformational changes in NECAB proteins may induce antibiotic biosynthesis monooxygenase domain dimerization, potentially activating some enzymatic properties. However, the substrate for this enzymatic activity remains uncertain. Alternatively, calcium-mediated conformational changes might influence protein interactions or the subcellular localization of NECAB proteins by controlling the availability of protein–protein interaction domains situated between the EF hands and the antibiotic biosynthesis monooxygenase domain. This review summarizes what is known about genomic organization, tissue expression, intracellular localization, interac

关键词： calcium EF hand mitochondria nervous system signal transduction

Why Hong kong Ranks Highest in Life Expectancy: Looking for Answers from Data Science and Social Sciences

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Journal of Social Computing 2022年第3期3卷 250-261页

作者： Ting Xu Ming-sum Tsui Dah Ming Chiu the Department of Information Engineering Chinese University of Hong KongHong Kong 999077China Felizberta Lo Padilla Tong School of Social Sciences Caritas Institute of Higher EducationHong Kong 999077China Department of Information Engineering Chinese University of Hong Kongand also with Data Science Research CenterCaritas Institute of Higher EducationHong Kong 999077China

In trying to explain why Hong kong of China ranks highest in life expectancy in the world,we review what various experts are hypothesizing,and how data science methods may be used to provide more evidence-based *** more data become available,we find some data analysis studies were too simplistic,while others too overwhelming in answering this challenging *** find the approach that analyzes life expectancy related data(mortality causes and rate for different cohorts)inspiring,and use this approach to study a carefully selected set of targets for *** discussing the factors that matter,we argue that it is more reasonable to try to identify a set of factors that together explain the phenomenon.

关键词： life expectancy data science social science population

Topological feature engineering for machine learning based halide perovskite materials design

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npj Computational Materials 2022年第1期8卷 1943-1950页

作者： D.Vijay Anand Qiang Xu JunJie Wee kelin Xia Tze Chien sum Division of Mathematical Sciences School of Physical and Mathematical SciencesNanyang Technological UniversitySingapore637371Singapore Division of Physics&Applied Physics School of Physical and Mathematical SciencesNanyang Technological UniversitySingapore637371Singapore

Accelerated materials development with machine learning(ML)assisted screening and high throughput experimentation for new photovoltaic materials holds the key to addressing our grand energy ***-driven ML is envisaged as a decisive enabler for new perovskite materials ***,its full potential can be severely curtailed by poorly represented molecular descriptors(or fingerprints).Optimal descriptors are essential for establishing effective mathematical representations of quantitative structure-property *** we reveal that our persistent functions(PFs)based learning models offer significant accuracy advantages over traditional descriptor based models in organic-inorganic halide perovskite(OIHP)materials design and have similar performance as deep learning *** multiscale simplicial complex approach not only provides a more precise representation for OIHP structures and underlying interactions,but also has better transferability to ML *** results demonstrate that advanced geometrical and topological invariants are highly efficient feature engineering approaches that can markedly improve the performance of learning models for molecular data ***,new structure-property relationships can be established between our invariants and *** anticipate that our molecular representations and featurization models will transcend the limitations of conventional approaches and lead to breakthroughs in perovskite materials design and discovery.

关键词： perovskite halide invariants

Fine-tuning of mechanical properties in a Zn-Ag-Mg alloy via cold plastic deformation process and post-deformation annealing

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Bioactive Materials 2021年第10期6卷 3424-3436页

作者： Maria Wątroba Wiktor Bednarczyk Jakub kawałko Piotr Bała AGH University of Science and Technology Faculty of Metals Engineering and Industrial Computer ScienceAl.A.Mickiewicza 3030-059 KrakowPoland AGH University of Science and Technology Academic Centre for Materials and NanotechnologyAl.A.Mickiewicza 3030-059 KrakowPoland

In recent years,Zn-based materials have been extensively investigated as potential candidates for biodegradable implant *** introduction of alloying elements providing solid-solution strengthening and second phase strengthening seems crucial to provide a suitable platform for the thermo-mechanical strengthening of Zn *** this study,a systematic investigation of the microstructure,crystallographic texture,phase composition,and mechanical properties of a Zn-3Ag-0.5Mg(wt%)alloy processed through combined hot extrusion(HE)and cold rolling(CR),followed by short-time heat treatment(CR+HT)at 200◦C was ***,the influence of different annealing temperatures on the microstructure and mechanical properties was *** adequate combination of processing conditions during CR and HT successfully addressed brittleness obtained in the high-strength HE Zn-3Ag-0.5Mg *** controlling the microstructure,the most promising results were obtained in the sample subjected to 50%CR reduction and 5-min annealing,which were:ultimate tensile strength of 432 MPa,yield strength of 385 MPa,total elongation to failure of 34%,and Vickers microhardness of 125 *** obtained properties clearly exceed the mechanical benchmarks for biodegradable implant *** on the conducted investigation,brittle multi-phase Zn alloys’mechanical performance can be substantially enhanced to provide sufficient plasticity by grain refinement through cold deformation process,followed by short-time annealing to restore proper strength.

关键词： Zinc alloys Cold rolling Heat treatment Mechanical properties Grain refinement

Structural and luminescence studies of europium ions in lithium aluminium borophosphate glasses

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Journal of Rare Earths 2014年第7期32卷 585-592页

作者： Poh sum Wong Ming Hua Wan Rosli Hussin Hendrik O.Lintang Salasiah Endud Phosphor Research Group Department of Physics Faculty of Science Universiti Teknologi Malaysia Ibnu Sina Institute for Fundamental Science Studies Universiti Teknologi Malaysia Department of Chemistry Faculty of ScienceUniversiti Teknologi Malaysia

Eu3＋ doped borophosphate glasses with the chemical composition 20Li2O-30Al2O3-10B2O3-40P2O5-xEu2O3（where x=0.05 mol.%, 0.1 mol.%, 1.0 mol.%, 1.5 mol.% and 2.0 mol.%） were prepared by conventional melt quenching technique. The structural and luminescence properties of the prepared Eu3＋ doped borophosphate glasses were studied and compared with reported results. The XRD pattern showed the amorphous nature of the prepared glasses. Whereas, the FTIR spectra revealed the vibrational modes in the prepared glasses. The bonding parameters（ β and ？） were calculated through the excitation spectra. Judd-Ofelt（J-O） intensity parameters were calculated from the emission spectra and were used to determine transition probability（A）, stimulated emission cross-section（σE P）, radiative lifetime（τR） and branching ratios（βexp） for the transition 5D0→7Fj（j=1, 2, 3 and 4） of Eu3＋ ions. Furthermore, the luminescence intensity ratio（R） of 5D0→7F2 to 5D0→7F1 transition was also calculated. Transition 5D0→7F2 had the highest value of stimulated emission cross-section and branching ratios and the results were comparable with the reported values. This indicated that the present glass is promising host material for Eu3＋ doped fiber amplifiers.

关键词： europium ions luminescence properties borophosphate glasses Judd^Ofelt analysis decay time rare earths

Contents of four active components in different commercial crude drugs and preparations of Danshen (Salvia miltiorrhiza)

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Acta Pharmacologica Sinica 2002年第12期23卷 110-115页

作者： Susan Wai sum LEUNG,Yaw Loong SIOW,Ricky Ying keung MAN Department of Pharmacology Faculty of Medicine University of Hong kong 21 Sassoon Road Hong kong China Department of Pharmacology Faculty of Medicine University of Hong kong 21 Sassoon Road Hong kong China Department of Pharmacology Faculty of Medicine University of Hong kong 21 Sassoon Road Hong kong China Department of Pharmacology University of Hong kong 21 Sassoon Road Hong kong China

AIM: To detect the contents of four active components of Salvia miltiorrhiza in various commercially available danshen crude drugs and preparations. METHODS: Commercially available danshen crude drugs from different sources, as well as danshen pills and intravenous injection preparations containing danshen alone or in combination with other herbs were collected. The composition of these danshen samples was analyzed using HPLC. Specifically, the amounts of magnesium tanshinoate B (MTB), danshensu, isotanshinone IIA, and ctyptotanshinone were determined. In some of these samples, the content of MTB was further confirmed by liquid chromatography-tandem mass spectrometer (LC-MS)/MS method. RESULTS: There were great variations in the amount of the four active ingredients in the commercially available danshen crude drugs and drug preparations in this study. The amount of MTB was the highest among the four components measured in the crude drugs. However, the amounts of MTB in all danshen preparations were much

关键词： Salvia miltiorrhiza magnesium tanshinoate B (MTB) high pressure liquid chromatography

Origins of the long-range exciton diffusion in perovskite nanocrystal films: photon recycling vs exciton hopping

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Light(Science & Applications) 2021年第1期10卷 41-49页

作者： David Giovanni Marcello Righetto Qiannan Zhang Jia Wei Melvin Lim Sankaran Ramesh Tze Chien sum Division of Physics and Applied Physics School of Physical and Mathematical SciencesNanyang Technological University(NTU)21 Nanyang LinkSingapore 637371Singapore Energy Research Institute@NTU(ERI@N) Interdisciplinary Graduate SchoolNanyang Technological University50 Nanyang AvenueS2-B3a-01Singapore 639798Singapore

The outstanding optoelectronic performance of lead halide perovskites lies in their exceptional carrier diffusion *** the perovskite material dimensionality is reduced to exploit the quantum confinement effects,the disruption to the perovskite lattice,often with insulating organic ligands,raises new questions on the charge diffusion ***,we report direct imaging of>1μm exciton diffusion lengths in CH3NH3PbBr3 perovskite nanocrystal(PNC)***,the resulting exciton mobilities in these PNC films can reach 10±2cm^(2)V^(-1) s^(-1),,which is counterintuitively several times higher than the carrier mobility in 3D perovskite *** show that this ultralong exciton diffusion originates from both efficient inter-NC exciton hopping(via Forster energy transfer)and the photon recycling process with a smaller yet significant ***,our study not only sheds new light on the highly debated origins of the excellent exciton diffusion in PNC films but also highlights the potential of PNCs for optoelearonic applications.

关键词： properties. perovskite diffusion

Inhomogeneity of Grain Boundaries of ZnO Varistor

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Journal of Materials Science & Technology 1994年第4期10卷 273-278页

作者： Hongtao sum Qin ZHOU Liangying ZHANG and X YAO (Electronic Materials Research Laboratory, Xi’an Jiaotong University, Xi’an 710049, China)(To whom correspondence should be addressed) Xi'an Jiaotong Univ Xi'an China

The zinc oxide varistor with a low threshold voltage and large grain size was derived with ZnO crystalline seeds from a molten salt process The chemical composition and I-V characteristics of single grains and single grain boundaries were determined by means of energy dispersive spectrum (EDS) and microcontact measurement respectively. Temperatu re dependence of dielectric loss at various frequencies and voltage dependence of capacitance were carefully measured. Based on these experimental data. the barrier heights of giain boundaries are estimated to be 0.2. 0.5 and 0.6 eV respectively corresponding to thick, th in and direct contact grain boundaries. In addition. a computerized electrical circuit simufation is employed in simulating I-V characteristics of single grain boundary within ZnO varistor. By adjustjng parameters of resistor and diode, a general agreement between the measured data and simulated curves is achieved

关键词： ZnO Figure Inhomogeneity of Grain Boundaries of ZnO Varistor