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Navigation Finsler metrics on a gradient Ricci soliton

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applied Mathematics(A Journal of Chinese Universities) 2024年第2期39卷 266-275页

作者： LI Ying MO Xiao-huan WANG Xiao-yang Department of applied Mathematics Zhejiang University of TechnologyHangzhou 310023China Key Laboratory of pure and applied Mathematics School of Mathematical SciencesPeking UniversityBeijing 100871China school of Mathematics and Statistics Beijing Institute of TechnologyBeijing 100081China

In this paper,we study a class of Finsler metrics defined by a vector field on a gradient Ricci soliton.We obtain a necessary and sufficient condition for these Finsler metrics on a compact gradient Ricci soliton to be of isotropic S-curvature by establishing a new integral inequality.Then we determine the Ricci curvature of navigation Finsler metrics of isotropic S-curvature on a gradient Ricci soliton generalizing result only known in the case when such soliton is of Einstein type.As its application,we obtain the Ricci curvature of all navigation Finsler metrics of isotropic S-curvature on Gaussian shrinking soliton.

关键词： gradient Ricci soliton navigation Finsler metric isotropic S-curvature Ricci curvature Gaussian shrinking soliton

Thermally activated delayed fluorescence carbazole-triazine dendrimer with bulky substituents

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Aggregate 2024年第1期5卷 236-243页

作者： Hiroki Ikebe Kohei Nakao Eri Hisamura Minori Furukori Yasuo Nakayama Takuya Hosokai Minlang Yang Guanting Liu Takuma Yasuda Ken Albrecht Interdisciplinary graduate school of Engineering sciences Kyushu UniversityFukuokaJapan Institute for Materials Chemistry and Engineering Kyushu UniversityKasugaJapan Department of pure and applied Chemistry Graduate School of Science and TechnologyTokyo University of ScienceNodaChibaJapan National Metrology Institute of Japan(NMIJ) National Institute of Advanced Industrial Science and Technology(AIST)TsukubaIbarakiJapan Institute for Advanced Study Kyushu UniversityNishi-kuFukuokaJapan

Carbazole-triazine dendrimers with a bulky terminal substituent were synthesized,and the thermally activated delayed fluorescence(TADF)property was investigated.Compared to unsubstituted carbazole dendrimers,dendrimers with bulky terminal substituents showed comparable to better photoluminescence quantum yields(PLQY)in neat films.Phenylfluorene(PF)-substituted dendrimers showed the highest PLQY of 81%,a smallΔEst of 0.06 eV,and the fastest reverse intersystem crossing(RISC)rate of∼1×10^(5 )s^(−1) compared to other dendrimers.Phosphorescence measurements of dendrimers and dendrons(fragments)indicate that the close proximity of the triplet energy of phenylfluorene-substituted carbazole dendrons(^(3)LE)to that of phenylfluorene-substituted dendrimers(^(1)CT,^(3)CT)contributes to RISC promotion and improves TADF efficiency.Terminal modification fine-tunes the energy level and suppresses intermolecular interactions,and this study provides a guideline for designing efficient solution-processable and non-doped TADF materials.

关键词： dendrimer OLED TADF 1 INTRODUCTION Thermally activated delayed fluorescence(TADF)materials which are inexpensive and highly efficient alternatives to fluorescent

Matrix Assisted Laser Desorption Ionization Time of Flight(MALDI-TOF)-Mass Spectrometry and^(13)C-NMR-Identified New Compounds in Paraberlinia bifoliolata(Ekop-Beli)Bark Tannins

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Journal of Renewable Materials 2024年第3期12卷 553-568页

作者： Liliane Nga Benoit Ndiwe Achille Bernard Biwolé Antonio Pizzi Jean Jalin Eyinga Biwole Joseph Zobo Mfomo Laboratory of Forest Resources and Wood Valorization Training Unit in Engineering SciencesPost Graduate School of Fundamental and Applied SciencesUniversity of DoualaP.O.Box 1872DoualaCameroun Laboratory of Mechanics Training Unit in Engineering SciencesPost Graduate School of Fundamental and Applied SciencesUniversity of DoualaP.O.Box 2701DoualaCameroun Laboratory of Studies and Research on Wood Material(LERMAB) University of LorraineNancyFrance

Extracts of plant origin,particularly tannins,are attracting growing interest for the sustainable development of materials in the industrial sector.The discovery of new tannins is therefore necessary.The aim of this work was to contribute to the understanding of the properties of Paraberlinia bifoliolata tannin by Matrix Assisted Laser Desorption Ionization Time of Flight Mass Spectroscopy MALDI-TOF/MS and Carbon 13 Nuclear Magnetic Resonance(13C NMR).The chemical composition of tannin extracted from Paraberlinia bifoliolata bark was determined,as was the mechanical strength of the resin hardened with Acacia nilotica extracts.Yield by successive water extraction was 35%.MALDI-TOF/MS analysis revealed the presence of three new compounds in this tannin,previously unknown in this family of extracts.These are 3-hydroxyproline acid,N-methyl-4-hydroxypipecolic acid and N-methyl-5-dihydroxypipecolic acid.The identification of the above molecules means that this tannin can be used for industrial applications,as a resin in the manufacture of particleboard and in the formulation of green corrosion inhibitors.This information is reinforced by 13C NMR spectrometry,which indicates the presence of several polyflavonoid units,confirming the condensed nature of the tannin.Thermomechanical analysis of the resin formed by the purified tannin of Paraberlinia bifoliolata to which a vegetal biohardener has been added provided a Modulus of Elasticity(MOE)value of 4840 MPa at 150℃,confirming its possible use as a binder resin in the manufacture of wood panels as well as for the formulation of a corrosion inhibitor.

关键词： Tannin Paraberlinia bifoliolata Central African wood species MALDI-TOF/MS 13C NMR bark extracts thermomechanical behaviour wood-binder

In vitro engineered models of neurodegenerative diseases

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BIOCELL 2024年第1期48卷 79-96页

作者： ZEHRA GÜL MORÇIMEN ŞEYMA TAŞDEMIR AYLIN ŞENDEMIR Bioengineering Department Graduate School of Natural and Applied SciencesEge UniversityIzmir35040Türkiye Bioengineering Department Faculty of Engineering and Natural ScienceCelal Bayar UniversityManisa45110Türkiye Bioengineering Department Ege UniversityIzmir35040Türkiye Department of Biomedical Technologies Graduate School of Natural and Applied SciencesEge UniversityIzmir35040Türkiye

Neurodegeneration is a catastrophic process that develops progressive damage leading to functional andstructural loss of the cells of the nervous system and is among the biggest unavoidable problems of our age.Animalmodels do not reflect the pathophysiology observed in humans due to distinct differences between the neuralpathways,gene expression patterns,neuronal plasticity,and other disease-related mechanisms in animals andhumans.Classical in vitro cell culture models are also not sufficient for pre-clinical drug testing in reflecting thecomplex pathophysiology of neurodegenerative diseases.Today,modern,engineered techniques are applied to developmulticellular,intricate in vitro models and to create the closest microenvironment simulating biological,biochemical,and mechanical characteristics of the in vivo degenerating tissue.In THIS review,the capabilities and shortcomings ofscaffold-based and scaffold-free techniques,organoids,and microfluidic models that best reflect neurodegeneration invitro in the biomimetic framework are discussed.

关键词： Neurodegenerative diseases In vitro models Scaffolds Organoids Microfluidic devices

Investigation of Microstructure, Microhardness and Thermal Properties of Ag-In Intermetallic Alloys Prepared by Vacuum Arc Meltings

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Journal of Wuhan University of Technology(Materials Science) 2024年第1期39卷 182-187页

作者： ÇELİK Erçevik ATA ESENER Pınar ÖZTÜRK Esra AKSÖZ Sezen Nevşehir HacıBektaşVeli University Department of Physics50300NevşehirTurkey Erciyes University Graduate School of Natural and Applied Sciences38039KayseriTurkey Kocaeli University Department of Physics41380KocaeliTurkey

Ag-In intermetallic alloys were produced by using vacuum arc furnace. Differential Scanning Calorimetry(DSC) and Energy Dispersive X-Ray Spectrometry(EDX) were used to determine the thermal properties and chemical composition of the phases respectively. Microhardness values of Ag-In intermetallics were calculated with Vickers hardness measurement method. According to the experimental results, Ag-34 wt%In intermetallic system generated the best results of energy saving and storage compared to other intermetallic systems. Also from the microhardness results, it was observed that intermetallic alloys were harder than pure silver and Ag-26 wt%In system had the highest microhardness value with 143.45 kg/mm^(2).

关键词： thermal properties microstructure characterization microhardness alloys material characterization

Corrosion behavior of pure metals(Ni and Ti)and alloys(316H SS and GH3535)in liquid GaInSn

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Nuclear Science and Techniques 2024年第3期35卷 70-83页

作者： Jian-Hui Yu Hong-Xia Xu Xiang-Xi Ye Bin Leng Han-Xun Qiu Xing-Tai Zhou school of Materials and Chemistry University of Shanghai for Science and TechnologyShanghai 200093China Shanghai Institute of applied Physics Chinese Academy of SciencesShanghai 201800China

In this study,the interactions between a Ga-based liquid metal,GaInSn,and several metal materials,including pure metals(Ni and Ti)and alloys(316H stainless steel(SS)and GH3535),at 650℃were investigated.The aim was to evaluate the corrosion performance and select a suitable candidate material for use as a molten salt manometer diaphragm in thermal energy storage systems.The results indicated that the alloys(316H SS and GH3535)exhibited less corrosion than pure metals(Ni and Ti)in liquid GaInSn.Ga-rich binary intermetallic compounds were found to form on the surfaces of all the tested metal materials exposed to liquid GaInSn,as a result of the decomposition of liquid GaInSn and its reaction with the constituent elements of the metal materials.The corrosion mechanism for all the tested materials exposed to liquid GaInSn was also investigated and proposed,which may aid in selecting the optimal candidate material when liquid GaInSn is used as the pressure-sensing medium.

关键词： Metal materials Liquid GaInSn Corrosion Intermetallic compounds Thermal energy storage systems

Induced pluripotent stem cells(iPSCs):molecular mechanisms of induction and applications

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Signal Transduction and Targeted Therapy 2024年第5期9卷 2065-2090页

作者： Jonas Cerneckis Hongxia Cai Yanhong Shi Department of Neurodegenerative Diseases Beckman Research Institute of City of HopeDuarteCA 91010USA Irell&Manella graduate school of Biological sciences Beckman Research Institute of City of HopeDuarteCA 91010USA

The induced pluripotent stem cell(iPSC)technology has transformed in vitro research and holds great promise to advance regenerative medicine.iPSCs have the capacity for an almost unlimited expansion,are amenable to genetic engineering,and can be differentiated into most somatic cell types.iPSCs have been widely applied to model human development and diseases,perform drug screening,and develop cell therapies.In this review,we outline key developments in the iPSC field and highlight the immense versatility of the iPSC technology for in vitro modeling and therapeutic applications.We begin by discussing the pivotal discoveries that revealed the potential of a somatic cell nucleus for reprogramming and led to successful generation of iPSCs.We consider the molecular mechanisms and dynamics of somatic cell reprogramming as well as the numerous methods available to induce pluripotency.Subsequently,we discuss various iPSC-based cellular models,from mono-cultures of a single cell type to complex three-dimensional organoids,and how these models can be applied to elucidate the mechanisms of human development and diseases.We use examples of neurological disorders,coronavirus disease 2019(COVID-19),and cancer to highlight the diversity of disease-specific phenotypes that can be modeled using iPSC-derived cells.We also consider how iPSC-derived cellular models can be used in high-throughput drug screening and drug toxicity studies.Finally,we discuss the process of developing autologous and allogeneic iPSC-based cell therapies and their potential to alleviate human diseases.

关键词： mechanisms programming holds

Particle morphology control for spherical powder fabrication using the ball milling process with DEM simulation

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Particuology 2024年第7期90卷 41-50页

作者： Battsetseg Jargalsaikhan Khulan Uranchimeg Amgalan Bor Kyung Sung Kim Heekyu Choi Research Institute of Future Convergence Changwon National UniversityChangwonGyoungnam 641-773Republic of Korea graduate school of Material Science Engineering Changwon National UniversityChangwonGyoungnam 641-773Republic of Korea Department of Chemical and Biological Engineering School of Engineering and Applied SciencesNational University of Mongoli1Ulaanbaatar 14200Mongolia Department of Mechatronics Convergence Engineering College of Future ConvergenceChangwon National UniversityChangwonGyoungnam 641-773Republic of Korea graduate school of Convergence on Culture Technology Changwon National UniversityChangwonGyoungnam 641-773Republic of Korea

Characteristics of spherical particles on copper powder and changing sizes were studied in a ball mill under various experimental conditions,such as different ball diameters,high rotation speeds,and milling times,using a discrete element method(DEM)simulation.This experiment has investigated the characteristics of spherical particle morphology evolution involved in the mechanical alloying of copper powder.The morphological evolution of the copper particle was analyzed using scanning electron microscopy(SEM).A spherical copper particle was shown with a roundness value using imageJ software.The DEM was used to simulate the ball motion in a planetary ball mill,and the impact energy and shear energy generated during the collision were analyzed to estimate the contact number between the ball and the ball wall.Therefore,as the size of the ball decreased,the number of ball-to-ball and ball-to-wall contacts increased accordingly,and the spherical shape of the copper powder changed.

关键词： Planetary ball mill DEM simulation Spherical particle morphology Copper powder Ball diameter

DYNAMICS FOR A CHEMOTAXIS MODEL WITH GENERAL LOGISTIC DAMPING AND SIGNAL DEPENDENT MOTILITY

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Acta Mathematica Scientia 2024年第3期44卷 1046-1063页

作者：涂馨予穆春来邱蜀燕张静 school of Mathematics and Statistics Southwest UniversityChongqing400715China Department of applied Mathematics The Hong Kong Polytechnic UniversityHung HomHong KongChina College of Mathematics and Statistics Chongqing UniversityChongqing401331China school of sciences Southwest Petroleum UniversityChengdu610500China

In this paper,we consider the fully parabolic Chemotaxis system with the general logistic source{ut=Δ(γ(v)u)+λu-μu^(k),x∈Ω,t>0,vt=△v+wz,x∈Ω,t>0,wt=-wz,x∈Ω,t>0,zt=△z-z+u,x∈Ω,t>0 whereΩ⊂ℝn(n≥1)is a smooth and bounded domain,λ≥0,μ≥0,κ>1,and the motility function satisfies thatγ(v)∈C3([0,∞)),γ(v)>0,γ′(v)≤0 for all v≥0.Considering the Neumann boundary condition,we obtain the global boundedness of solutions if one of the following conditions holds:(i)λ=μ=0,1≤nλ3;(ii)λ>0,μ>0,combined withκ>1,1≤n≤3 or k>n+2/4,,n>3.Moreover,we prove that the solution (u, v, w, z) exponentially converges to the constant steady state ((λ/μ)1/k-1,∫Ωv0dx+∫Ωw0dx/|Ω|,0,(λ/μ)1/k-1).

关键词： chemotaxis signal-dependent motility logistic source boundedness asymptotic behavior