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A functional tacrolimus-releasing nerve wrap for enhancing nerve regeneration following surgical nerve repair

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Neural Regeneration Research 2025年第1期20卷 291-304页

作者： Simeon C.Daeschler Katelyn j.W.So Konstantin Feinberg Marina Manoraj jenny Cheung jennifer Zhang Kaveh Mirmoeini jPaul Santerre Tessa Gordon Gregory hBorschel SickKids Research Institute Neuroscience and Mental Health ProgramTorontoONCanada Institute of Biomaterials and Biomedical Engineering University of TorontoTorontoONCanada Indiana University School of Medicine IndianapolisINUSA Division of Plastic and Reconstructive Surgery the Hospital for Sick ChildrenTorontoONCanada Translational Biology and Engineering Program Ted Rogers Centre for Heart ResearchInstitute of Biomedical EngineeringFaculty of DentistryUniversity of TorontoTorontoONCanada

Axonal regeneration following surgical nerve repair is slow and often incomplete,resulting in poor functional recovery which sometimes contributes to lifelong ***,there are no FDA-approved therapies available to promote nerve *** accelerates axonal regeneration,but systemic side effects presently outweigh its potential benefits for peripheral nerve *** authors describe herein a biodegradable polyurethane-based drug delivery system for the sustained local release of tacrolimus at the nerve repair site,with suitable properties for scalable production and clinical application,aiming to promote nerve regeneration and functional recovery with minimal systemic drug *** is encapsulated into co-axially electrospun polycarbonate-urethane nanofibers to generate an implantable nerve wrap that releases therapeutic doses of bioactive tacrolimus over 31 *** and drug loading are adjustable for applications in small and large caliber nerves,and the wrap degrades within 120 days into biocompatible *** released from the nerve wrap promotes axon elongation in vitro and accelerates nerve regeneration and functional recovery in preclinical nerve repair models while off-target systemic drug exposure is reduced by 80%compared with systemic *** its surgical suitability and preclinical efficacy and safety,this system may provide a readily translatable approach to support axonal regeneration and recovery in patients undergoing nerve surgery.

关键词： biodegradable local drug delivery nerve injury nerve regeneration nerve wrap tacrolimus

QSAR for biotoxication of aromatic compounds

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Chinese Science Bulletin 1997年第5期42卷 380-384页

作者： Liu, ZT Wang, ls Ni, h Kong, ZM Chinese Research Academy of Environmental Sciences Beijing China Department of Environmental Science Nanjing University Nanjing China

MANY congeneric chemicals of aromatic hydrocarbons are toxic organic materials. This note uses some available molecular descriptors such as the energy of molecular orbital and the molecular connectivity index to analyse the biotoxicities and the structure-effect relationships of aromatic compounds on aquatic organism and terrestrial mammal in the view of molecular structure and energy with the method of quantitative structure-activity relationship (QSAR),

关键词： classic aromatic compounds biotoxication biotic substitutability estimation.

Electronic structure of the SrAl_2O_4:Eu^(2+) persistent luminescence material

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journal of Rare Earths 2009年第4期27卷 550-554页

作者： jorma hls Taneli Laamanen Mika Lastusaari janne Niittykoski Pavel Novák Department of Chemistry University of Turku FI-20014 Turku Finland Turku University Centre for Materials and Surface (MatSurf) Turku Finland Graduate School of Materials Research (GSMR) Turku Finland Institute of Physics Academy of Sciences of the Czech Republic CZ-16253 Prague 6 Czech Republic

The electronic structure of the strontium aluminate （SrAl2O4：Eu^2＋） materials was studied with a combined experimental and theo- retical approach. The UV-VUV synchrotron radiation was applied in the experimental study while the electronic structure of the non-optimized and optimized crystal structure were investigated theoretically by using the density functional theory. The structure of the valence and conduction bands as well as the band gap energy of the material together with the position of the Eu2＋ 4f7 85712 ground state were calculated. The calculated band gap energy （6.4 eV） agreed well with the experimental value of 6.6 eV. The valence band consisted mainly of oxygen states whereas the bottom of the conduction band of strontium states. In agreement with the experimental results, the calculated 4f7 8S7r2 ground state of Eu2＋ lies in the energy gap of the host. The position of the 4f7 ground state depended on the Coulomb repulsion strength. The position of the 4f7 ground state with respect to the valence and conduction bands was discussed using theoretical and experimental evidence available.

关键词： strontium aluminate persistent luminescence electronic structure DFT calculation rare earths

Threshold photoelectron-photoion coincidence and its applica-tion to photoionization of molecules using synchrotron radiation

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Chinese Science Bulletin 1997年第10期42卷 809-814页

作者： Gao, h Zhang, YW Sheng, ls Qi, F Liu, YM National Synchrotron Radiation Laboratory University of Science and Technology of China Hefei China

PhOTOIONIZATION method is one of the powerful tools for the investigation of the molecular en-ergetic,structure and dynamic *** process of photoionization of a given systeminvolves at least three particles:the absorbe... 详细信息

关键词： threshold photoelectron threshold photoelectron-photoion coincidence synchrotron radiation.

FINITE ELEMENT ANALYSIS OF A LOCAL EXPONENTIALLYFITTED SChEME FOR TIME-DEPENDENTCONVECTION-DIFFUSION PROBLEMS

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journal of Computational Mathematics 1999年第3期17卷 225-232页

作者： Yue, XY jiang, ls Shih, TM Suzhou Univ Dept Math Suzhou 215006 Peoples R China Tongji Univ Inst Math Shanghai 200092 Peoples R China hong Kong Polytech Univ Dept Appl Math Hong Kong Hong Kong

In [16], Stynes and O' Riordan(91) introduced a local exponentially fitted finite element (FE) scheme for a singularly perturbed two-point boundary value problem without turning-point. An E-uniform h(1/2)-order accuracy was obtain for the epsilon-weighted energy norm. And this uniform order is known as an optimal one for global exponentially fitted FE schemes (see [6, 7, 12]). In present paper, this scheme is used to a parabolic singularly perturbed problem. After some subtle analysis, a uniformly in epsilon convergent order h\ln h\(1/2) + tau is achieved (h is the space step and tau is the time step), which sharpens the results in present literature. Furthermore, it implies that the accuracy order in [16] is actuallay h\ln h\(1/2) rather than h(1/2).

关键词： singularly perturbed exponentially fitted uniformly in epsilon convergent Petrov-Galerkin finite element method

EXAFS study of cation reordering in NaYF_4:Yb^(3+),Tb^(3+) up-conversion luminescence materials

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journal of Rare Earths 2014年第3期32卷 226-229页

作者： h.F.Brito j.h.ls T.Laamanen T.Laihinen M.Lastusaari L.Pihlgren L.C.V.Rodrigues T.Soukka Instituto de Química Universidade de S?o Paulo Department of Chemistry University of Turku Turku University Centre for Materials and Surfaces (MatSurf) Department of Chemistry University of Turku FI-20014 Turku Finland Turku University Centre for Materials and Surfaces (MatSurf) Turku Finland University of Turku Graduate School (UTUGS) Doctoral Programme in Physical and Chemical Sciences Graduate School of Materials Research (GSMR) Department of Biochemistry University of Turku

The NaYF4：yb3＋,Tb3＋（Xyb： 0.20, XTb： 0.04） materials were prepared using the co-precipitation method, lne as-preparea material was washed either with or without water in addition to ethanol and thereafter annealed for 5 h at 500℃. This resulted in materials with moderate or very high up-conversion luminescence intensity, respectively. The structural study carried out with X-ray powder diffraction revealed microstrains in the rare earth （R） sublattice that were relaxed for the material with very high up-conversion intensity thus decreasing energy losses. The local structural details were investigated with R LⅢ and Y K edge ex- tended X-ray absorption fine structure （EXAFS） using synchrotron radiation. Around 10 tool.% of the Yb3＋ ions were found to occupy the Na site in the material with very high up-conversion intensity. These Yb species formed clusters with the Tb3＋ ions occupying the regular Na/R sites. Such clustering enhanced the energy transfer between Yb3＋ and Tb3＋ thus intensifying the up-conversion emission.

关键词： EXAFS up-conversion ytterbium terbium cation reordering

Synchrotron radiation investigations of the Sr_2MgSi_2O_7:Eu^(2+),R^(3+) persistent luminescence materials

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journal of Rare Earths 2009年第4期27卷 529-538页

作者： Tuomas Aitasalo jukka hassinen jorma hls Taneli Laamanen Mika Lastusaari Marja Malkamki janne Niittykoski Pavel Novák Department of Chemistry University of Turku FI-20014 Turku Finland Turku University Centre for Materials and Surfaces (MatSurf) Turku Finland Graduate School of Materials Research (GSMR) Turku Finland Institute of Physics Academy of Sciences of the Czech Republic CZ-16253 Prague 6 Czech Republic

The electronic and defect energy level structure of polyerystalline Sr2MgSi2OT：Eu^2＋,R^3＋ persistent luminescence materials were studied with thermoluminescence and different synchrotron radiation spectroscopies （UV-VUV emission and excitation, X-ray absorption near-edge spectroscopy （XANES） and extended X-ray absorption f＇me structure （EXAFS））. Special attention was paid on the effect of the R3＋ co-dopants on the persistent luminescence properties of the materials. Theoretical calculations using the density functional theory （DFT） were carried out simultaneously with the experimental work. The experimental band gap energy （Eg） value of ca. 7.1 eV agreed very well with the DFT value of 6.7 eV. The variation of the Eg value was attempted to relate with the trap structure as well as with the different properties of the R3＋ co-dopants. The trap level energy distribution depended strongly on the R3＋ co-dopant except for the shallowest trap energy above the room temperature remaining practically the same, however. The different processes in the mechanism of persistent luminescence from Sr2MgSi2OT：Eu^2＋,R^3＋ were assembled and their contributions discussed.

关键词： strontium magnesium disilicate europium persistent luminescence synchrotron radiation thermoluminescence mechanism rare earths

Plasma density measurement and downstream etching of silicon and silicon oxide in Ar/NF3 mixture remote plasma source

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Plasma Science and Technology 2019年第6期21卷 52-57页

作者： h j YEOM D h ChOI Y S LEE j h KIM D j SEONG S j YOU h C LEE Korea Research Institute of Standards and Science(KRISS) Daejeon 34113 Republic of Korea Department of Physics Chungnam National University Daejeon 34134 Republic of Korea

In this study,plasma density measurements were performed near the plume region of the remote plasma source (RPS) in Ar/NF3 gas mixtures using a microwave cutoff *** measured plasma density is in the range of 1010-1011 cm-3 in the discharge conditions with RPS powers of 2-4 kW and gas pressures of 0.87-4 *** plasma density decreased with increasing gas pressures and RPS powers under various Ar/NF3 mixing *** decrease in the plasma density measured at the fixed measurement position (plume region) can be understood by the reduction of the electron energy relaxation length with increases in the gas pressures and mixing ratio of NF3/(Ar/NF3).We also performed downstream etching of silicon and silicon oxide films in this *** etch rate of the silicon films significantly increases while the silicon oxide is slightly etched with the gas pressures and *** was also found that the etch rate strongly depends on the wafer position on the processing chamber electrode,and that the etch selectivity reached 96-131 in the discharge conditions of RF powers (3730-4180 W) and gas pressures (3.6-4 Torr).

关键词： remote plasma source electron density cutoff probe downstream etch

A structural topological optimization method for multi-displacement constraints and any initial topology configuration

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Acta Mechanica Sinica 2010年第5期26卷 735-744页

作者： j. h. Rong j. h. Yi School of Automotive and Mechanical Engineering Changsha University of Science and TechnologyChangsha 410076 China

In density-based topological design, one expects that the final result consists of elements either black （solid material） or white （void）, without any grey areas. Moreover, one also expects that the optimal topology can be obtained by starting from any initial topology configuration. An improved structural topological optimization method for multidisplacement constraints is proposed in this paper. In the proposed method, the whole optimization process is divided into two optimization adjustment phases and a phase transferring step. Firstly, an optimization model is built to deal with the varied displacement limits, design space adjustments, and reasonable relations between the element stiffness matrix and mass and its element topology variable. Secondly, a procedure is proposed to solve the optimization problem formulated in the first optimization adjustment phase, by starting with a small design space and advancing to a larger deign space. The design space adjustments are automatic when the design domain needs expansions, in which the convergence of the proposed method will not be affected. The final topology obtained by the proposed procedure in the first optimization phase, can approach to the vicinity of the optimum topology. Then, a heuristic algorithm is given to improve the efficiency and make the designed structural topology black/white in both the phase transferring step and the second optimization adjustment phase. And the optimum topology can finally be obtained by the second phase optimization adjustments. Two examples are presented to show that the topologies obtained by the proposed method are of very good 0/1 design distribution property, and the computational efficiency is enhanced by reducing the element number of the design structural finite model during two optimization adjustment phases. And the examples also show that this method is robust and practicable.

关键词： Topological optimization Displacement constraint Continuum structure Design space adjustment Rational approximation material model