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the role of vascularization in nerve regeneration of nerve graft

Neural Regeneration Research 2020年第9期15卷 1573-1579页

作者： tiam M.Saffari Meiwand Bedar Caroline A.Hundepool allen t.bishop Alexander Y.Shin Department of Orthopedic Surgery Mayo ClinicRochesterMNUSA Department of Plastic Reconstructive and Hand SurgeryErasmus Medical CenterRotterdamthe Netherlands

Vascularization is an important factor in nerve graft survival and function. the specific molecular regulations and patterns of angiogenesis following peripheral nerve injury are in a broad complex of pathways. this review aims to summarize current knowledge on the role of vascularization in nerve regeneration, including the key regulation molecules, and mechanisms and patterns of revascularization after nerve injury. Angiogenesis, the maturation of pre-existing vessels into new areas, is stimulated through angiogenic factors such as vascular endothelial growth factor and precedes the repair of damaged nerves. Vascular endothelial growth factor administration to nerves has demonstrated to increase revascularization after injury in basic science research. In the clinical setting, vascularized nerve grafts could be used in the reconstruction of large segmental peripheral nerve injuries. Vascularized nerve grafts are postulated to accelerate revascularization and enhance nerve regeneration by providing an optimal nutritional environment, especially in scarred beds, and decrease fibroblast infiltration. this could improve functional recovery after nerve grafting, however, conclusive evidence of the superiority of vascularized nerve grafts is lacking in human studies. A well-designed randomized controlled trial comparing vascularized nerve grafts to non-vascularized nerve grafts involving patients with similar injuries, nerve graft repair and follow-up times is necessary to demonstrate the efficacy of vascularized nerve grafts. Due to technical challenges, composite transfer of a nerve graft along with its adipose tissue has been proposed to provide a healthy tissue bed. Basic science research has shown that a vascularized fascial flap containing adipose tissue and a vascular bundle improves revascularization through excreted angiogenic factors, provided by the stem cells in the adipose tissue as well as by the blood supply and environmental support. While it was previou

关键词： angiogenesis fascial flap nerve graft nerve injury nerve regeneration peripheral nerve vascular endothelial growth factor vascularization vascularized nerve graft

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Gene expression profiles of human adipose-derived mesenchymal stem cells dynamically seeded on clinically available processed nerve allografts and collagen nerve guides

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Neural Regeneration Research 2021年第8期16卷 1613-1621页

作者： Femke Mathot Nadia Rbia Roman thaler Allan B.Dietz Andre Jvan Wijnen allen t.bishop Alexander Y.Shin Department of Orthopedic Surgery Mayo ClinicRochesterMNUSA Department of Plastic Surgery RadboudumcNijmegenThe Netherlands Department of Dermatology Erasmus Medical CenterRotterdamThe Netherlands Department of Biochemistry and Molecular Biology Mayo ClinicRochesterMNUSA Department of Laboratory Medicine and Pathology Mayo ClinicRochesterMNUSA

It was hypothesized that mesenchymal stem cells(MSCs) could provide necessary trophic factors when seeded onto the surfaces of commonly used nerve graft substitutes. We aimed to determine the gene expression of MSCs when influenced by Avance■ Nerve Grafts or Neura Gen■ Nerve Guides. Human adipose-derived MSCs were cultured and dynamically seeded onto 30 Avance■ Nerve Grafts and 30 Neura Gen■ Nerve Guides for 12 hours. At six time points after seeding, quantitative polymerase chain reaction analyses were performed for five samples per group. Neurotrophic [nerve growth factor(NGF), glial cell line-derived neurotrophic factor(GDNF), pleiotrophin(PtN), growth associated protein 43(GAP43) and brain-derived neurotrophic factor(BDNF)], myelination [peripheral myelin protein 22(PMP22) and myelin protein zero(MPZ)], angiogenic [platelet endothelial cell adhesion molecule 1(PECAM1/CD31) and vascular endothelial cell growth factor alpha(VEGFA)], extracellular matrix(ECM) [collagen type alpha I(COL1A1), collagen type alpha III(COL3A1), Fibulin 1(FBLN1) and laminin subunit beta 2(LAMB2)] and cell surface marker cluster of differentiation 96(CD96) gene expression was quantified. Unseeded Avance■ Nerve Grafts and Neura Gen■ Nerve Guides were used to evaluate the baseline gene expression, and unseeded MSCs provided the baseline gene expression of MSCs. the interaction of MSCs with the Avance■ Nerve Grafts led to a short-term upregulation of neurotrophic(NGF, GDNF and BDNF), myelination(PMP22 and MPZ) and angiogenic genes(CD31 and VEGFA) and a long-term upregulation of BDNF, VEGFA and COL1A1. the interaction between MSCs and the Neura Gen■ Nerve Guide led to short term upregulation of neurotrophic(NGF, GDNF and BDNF) myelination(PMP22 and MPZ), angiogenic(CD31 and VEGFA), ECM(COL1A1) and cell surface(CD96) genes and long-term upregulation of neurotrophic(GDNF and BDNF), angiogenic(CD31 and VEGFA), ECM genes(COL1A1, COL3A1, and FBLN1) and cell surface(CD96) genes. Analysis demonstrat

关键词： Avance■Nerve Grafts dynamic seeding mesenchymal stem cell NeuraGen■Nerve Guides peripheral nerve repair qPCR

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Combining innovative science and policy to improve air quality in cities with refining and chemicals manufacturing： the case study of Houston, texas, USA

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Frontiers of Chemical Science and Engineering 2017年第3期11卷 293-304页

作者： David t. allen University of texas Austin Department of Chemical Engineering and Center for Energy and Environmental Resources Austin TX 78759 USA

In Houston, a combination of urban emissions from a city of 4 million people, coupled with emissions from extensive petroleum refining and chemical manufacturing, leads to conditions for photochemistry that are unique in the United States, and historically, the city had experienced some of the highest ozone concentrations recorded in the United States. Large air quality field studies （the texas Air Quality Studies or texAQS I and II） were conducted to determine root causes of the high ozone concentrations. Hundreds of air quality investigators, from around the world, deployed instruments on aircraft, on ships, and at fixed ground sites to make extensive air quality measurements; detailed photochemical modeling was used to interpret and assess the implications of the measurements. the texas Air Quality Studies revealed that both continuous and episodic emissions of light alkenes, which came to be called highly reactive volatile organic compounds, played a critical role in the formation of ozone and other photochemical oxidants in the region. Under- standing and quantifying the role of these emissions in regional air quality required innovations in characterizing emissions and in photochemical modeling. Reducing emissions required innovative policy approaches. these coupled scientific and policy innovations are described, and the result, substantially cleaner air for Houston, is documented. the lessons learned from the Houston air quality experience are relevant to cities with similar population and industrial profiles around the world.

关键词： ozone air quality highly reactive volatile organic compounds Houston

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INtERACtION OF A FLOAtING ELLIPtIC CYLINDER WItH A VIBRAtING CIRCULAR CYLINDER

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Journal of Hydrodynamics 2006年第4期18卷 481-491页

作者： SUN Ren CHWANG allen t. Department of Engineering Mechanics Shanghai Jiaotong University Shanghai 200240 China Department of Mechanical Engineering The University ofHong Kong Hong Kong China

the nonlinear hydrodynamic interaction between a floating elliptic cylinder and a vibrating circular cylinder immersed in an infinite fluid was investigated. By taking the added masses of the two-cylinder system into account, the dynamical equations of motion were formulated from the Lagrange equations of motion. the dynamical behaviors of these two cylinders were analyzed numerically for some typical situations, and the results show that the presence of a vibrating circular cylinder has a significant influence on the planar motion of a floating elliptic cylinder. the hydrodynamic interaction between them results in complicated nonlinear behaviors of the floating cylinder. It is found that oscillatory motion of the elliptic cylinder takes place in response to the vibrating mode of the circular one.

关键词： hydrodynamic interaction two-body interaction potential flow planar motion elliptic cylinder vibrating cylinder

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transition waves and nonlinear interactions in the near wake of a circular cylinder

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Science China Mathematics 1997年第8期40卷 849-859页

作者：凌国灿 allen t.Chwang 牛家玉王冬(女菱) Laboratory for Nonlinear Mechanics of Continuous Media Institute of MechanicsChinese Academy of SciencesBeijing 100080China Department of Mechanical Engineering University of Hong KongHong Kong Institute of Mechanics Chinese Acaderny of SciencesBeijing 100080China

transition waves and interactions between two kinds of instability-vortex shedding and transition wave in the near wake of a circular cylinder in the Reynolds number range 3 000-10 000 are studied by a domain decomposition hybrid numerical *** on high resolution power spectral analyses for velocity new results on the Reynolds-number dependence of the transition wave frequency,***/fa^Re0.87 are *** new predictions are in good agreement with the experimental results of Wei and Smith but different from Braza's prediction and some early experimental results ft/fa-Re0.5 given by Bloor et *** multi-interactions between two kinds of vortex are clearly visualized *** strong nonlinear interactions between the two independent frequencies (ft,fa) leading to spectra broadening to form the coupling mfs±nft are predicted and analyzed numerically,and the characteristics of the transition are *** variations of the transition wave and its coupling are *** mechanism of the flow transition in the near wake before occurrence of the three-dimensional evolution is provided.

关键词： transition wave nonlinear interaction near wake circular cylinder.

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tHE BEHAVIOUR OF tHE FLOW INVARIANtS OF LOCAL UNStEADY HOMOGENEOUS SHEAR FLOW

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Journal of Hydrodynamics 1994年第3期6卷 25-33页

作者： allen t.Chwang Department of Mechanical Engineering University of Hong KongHong Kong

In this paper the vorticity equation and the rate- of- swain tensor equation of unsteady homogeneous shear flow of an incompressible fluid are investigated and five scalar invariants, such as enstrophy, etc. , equations are obtained. then according to these scalar invariants equations and a pressure distribution assumption, the stability of the solution and its special behaviours are discussed. It is found out that under certain conditions the enstrophy and the second invariant of the rate-of-strain tensor will approach to infinity periodically. It is so-called blow up phenomenon and has the close relation with the burst phenomenon.

关键词： vorticity invariant blow up.

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100pt/cm single-point MEMS magnetic gradiometer from a commercial accelerometer

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Microsystems & Nanoengineering 2020年第1期6卷 602-614页

作者： Josh Javor Alexander Stange Corey Pollock Nicholas Fuhr David J.bishop Department of Mechanical Engineering Boston UniversityBostonMA 02215USA Division of Materials Science and Engineering Boston UniversityBostonMA 02215USA Department of Electrical and Computer Engineering Boston UniversityBostonMA 02215USA Department of Physics Boston UniversityBostonMA 02215USA Department of Biomedical Engineering Boston UniversityBostonMA 02215USA

Magnetic sensing is present in our everyday interactions with consumer electronics and demonstrates the potential for the measurement of extremely weak biomagnetic fields,such as those of the heart and *** this work,we leverage the many benefits of microelectromechanical system(MEMS)devices to fabricate a small,low-power,and inexpensive sensor whose resolution is in the range of biomagnetic *** present,biomagnetic fields are measured only by expensive mechanisms such as optical pumping and superconducting quantum interference devices(SQUIDs),suggesting a large opportunity for MEMS technology in this *** prototype fabrication is achieved by assembling micro-objects,including a permanent micromagnet,onto a postrelease commercial MEMS accelerometer using a pick-and-place *** this system,we demonstrate a room-temperature MEMS magnetic *** air,the sensor’s response is linear,with a resolution of 1.1 nt cm^(−1),spans over 3 decades of dynamic range to 4.6µt cm^(−1),and is capable of off-resonance measurements at low *** a 1mtorr vacuum with 20 dB magnetic shielding,the sensor achieves a 100 pt cm^(−1) resolution at *** resolution represents a 30-fold improvement compared with that of MEMS magnetometer technology and a 1000-fold improvement compared with that of MEMS gradiometer *** sensor is capable of a small spatial resolution with a magnetic sensing element of 0.25 mm along its sensitive axis,a>4-fold improvement compared with that of MEMS gradiometer *** calculated noise floor of this platform is 110 ftcm^(−1) Hz−1/2,and thus,these devices hold promise for both magnetocardiography(MCG)and magnetoencephalography(MEG)applications.

关键词： accelerometer magnetometer everyday

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Porous Medium Flow with Both a Fractional Potential Pressure and Fractional time Derivative

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Chinese Annals of Mathematics,Series B 2017年第1期38卷 45-82页

作者： Mark allen Luis CAFFARELLI Alexis VASSEUR Department of Mathematics The University of Texas at AustinAustinTX 78712USA

the authors study a porous medium equation with a right-hand side. the operator has nonlocal diffusion effects given by an inverse fractional Laplacian *** derivative in time is also fractional and is of Caputo-type, which takes into account"memory". the precise model isD_t~αu- div(u(-Δ)^(-σ)u) = f, 0 the problem over {t ∈ R^+, x ∈ R^n} with nonnegative initial data u(0, x) ≥0 as well as the right-hand side f ≥ 0. the existence for weak solutions when f, u(0, x)have exponential decay at infinity is proved. the main result is H¨older continuity for such weak solutions.

关键词： Caputo derivative Marchaud derivative Porous medium equation Hlder continuity Nonlocal diffusion

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Virtual Australia:its key elementsknow,think,communicate

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International Journal of Digital Earth 2008年第1期1卷 66-87,I0005页

作者： B.thompson t.O.Cha R.Slee P.Kinne A.Jahshan P.Woodgate I.bishop D.McKenzie Spatial Information Infrastructure Department of Sustainability and EnvironmentLevel 13Marland House570 Bourke StreetMelbourne Victoria 3000Australia Oracle Fusion Middleware Sales Oracle Corporation Asia Pacific4 Julius AvenueNorth Ryde NSW 2113Australia Open Spatial technologies Pty Ltd 433 Logan RoadStones Corner QLD 4120Australia Australian Cooperative Research Centre for Spatial Information 723 Swanston StreetUniversity of MelbourneVictoria 3010Australia Department of Geomatics The University of Melbourne VictoriaAustralia

Virtual Australia is not a well-defined or agreed *** discussion paper conceptualises Virtual Australia as a‘virtual[digital]model containing and representing all non-trivial objects and their contextual environmentfrom blue sky to bedrockin real world Australia’.It describes a scenario for Virtual Australia,one or two decades from now,in which the locations and conditions of non-trivial objects and their environment are updated automatically through a combination of remote sensing and wireless communication technologies in support of a‘Supranet’.It then examines the concept of the‘Supranet’a pervasive information network based largely on wireless technology linking the physical world to a virtual model in real timeand develops and discusses three principal characteristics of the Supranet:the ability to have or collect specific information(know);the ability to process information(think);and the ability to communicate that ***,in the near future,any or all non-trivial devices are to some extent able to know,think and communicate,the potential for object autonomy will be realised.

关键词： virtual spatial supranet digital information sensors motes innovation Australia

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the transformation of a Schwarzschild Black Hole Linear Perturbations to Bondi Frame

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Journal of Modern Physics 2014年第16期5卷 1767-1778页

作者： Amos S. Kubeka Nigel t. bishop Department of Mathematical Sciences University of South Africa Unisa South Africa Department of Mathematics (Pure and Applied) Rhodes University Grahamstown South Africa

We extend standard linear perturbations of a Schwarzschild black hole by Chandrasekhar to Bondi frame by transforming both even and odd parity perturbations when angular momentum l = 2.

关键词： Black Hole Linear Perturbations Null Cone Formalism Bondi-Sachs Formalism Odd Parity Perturbations Even Parity Perturbations

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