排序方式: 共有12条查询结果,搜索用时 15 毫秒
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A novel (to our knowledge) dual-core ytterbium (Yb(3+)) doped fiber, as an optically pumped amplifier, boosts the output power from a 1060 nm swept source laser beyond 250 mW, while providing a wavelength tuning range of 93 nm, for optical coherence tomography (OCT) imaging. The design of the dual-core Yb-doped fiber amplifier and its multiple wavelength optical pumping scheme to optimize output bandwidth are discussed. Use of the dual-core fiber amplifier showed no appreciable degradation to the coherence length of the seed laser. The signal intensity improvement of this amplifier is demonstrated on a multichannel in vivo OCT imaging system at 1060 nm. 相似文献
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Mariampillai B Alberico D Bidau V Lautens M 《Journal of the American Chemical Society》2006,128(45):14436-14437
A norbornene-mediated palladium-catalyzed tandem alkylation/cyanation sequence is described in which an alkyl-aryl bond and a nitrile-aryl bond are formed in one pot. A variety of sterically hindered, five-, six-, and seven-membered ring benzonitriles were synthesized in good yields from easily accessible starting materials. 相似文献
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[reaction: see text] A palladium-catalyzed arylation of allylic acetates followed by beta-acetoxy elimination was shown to produce Heck-type coupling products. Optimal reaction conditions employed ligand-free palladium on carbon in the presence of tetrabutylammonium chloride, a trialkylamine base, and water. 相似文献
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Ullah H. Davoudi B. Mariampillai A. Hussain G. Ikram M. Vitkin I. A. 《Laser Physics》2012,22(4):797-804
The increase of glucose levels in blood changes the viscosity of flowing fluids and shape of the erythrocytes. Both of these
can affect the details of light scattering as can be quantified via decorrelation times measured by optical coherence tomography
(OCT). The relative contributions of these competing effects have been studied by examining the motion dynamics of deformable
asymmetrical (red blood cells, RBCs with ∼7 μm diameter and ∼2 μm thickness) and non deformable symmetrical (polystyrene microspheres,
PSM with 1.4 μm diameter) flowing scattering particles. The fluid flow under the action of gravity was modulated by changing
the glucose concentrations. Quantitative analysis of the OCT’s M-mode autocorrelation functions enabled the derivations of
the translational diffusion coefficients. These systematic studies are aimed at eventual tissue imaging scenarios with speckle-variance
OCT to obtain local glucose concentrations maps. 相似文献
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Munce NR Mariampillai A Standish BA Pop M Anderson KJ Liu GY Luk T Courtney BK Wright GA Vitkin IA Yang VX 《Optics letters》2008,33(7):657-659
A novel flexible scanning optical probe is constructed with a finely etched optical fiber strung through a platinum coil in the lumen of a dissipative polymer. The packaged probe is 2.2 mm in diameter with a rigid length of 6mm when using a ball lens or 12 mm when scanning the fiber proximal to a gradient-index (GRIN) lens. Driven by constant high voltage (1-3 kV) at low current (< 5 microA), the probe oscillates to provide wide forward-viewing angle (13 degrees and 33 degrees with ball and GRIN lens designs, respectively) and high-frame-rate (10-140 fps) operation. Motion of the probe tip is observed with a high-speed camera and compared with theory. Optical coherence tomography (OCT) imaging with the probe is demonstrated with a wavelength-swept source laser. Images of an IR card as well as in vivo Doppler OCT images of a tadpole heart are presented. This optomechanical design offers a simple, inexpensive method to obtain a high-frame-rate forward-viewing scanning probe. 相似文献
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Speckle variance detection of microvasculature using swept-source optical coherence tomography 总被引:1,自引:0,他引:1
Mariampillai A Standish BA Moriyama EH Khurana M Munce NR Leung MK Jiang J Cable A Wilson BC Vitkin IA Yang VX 《Optics letters》2008,33(13):1530-1532
We report on imaging of microcirculation by calculating the speckle variance of optical coherence tomography (OCT) structural images acquired using a Fourier domain mode-locked swept-wavelength laser. The algorithm calculates interframe speckle variance in two-dimensional and three-dimensional OCT data sets and shows little dependence to the Doppler angle ranging from 75 degrees to 90 degrees . We demonstrate in vivo detection of blood flow in vessels as small as 25 microm in diameter in a dorsal skinfold window chamber model with direct comparison with intravital fluorescence confocal microscopy. This technique can visualize vessel-size-dependent vascular shutdown and transient vascular occlusion during Visudyne photodynamic therapy and may provide opportunities for studying therapeutic effects of antivascular treatments without on exogenous contrast agent. 相似文献
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We report the use of optical coherence tomography (OCT) for measuring dextrorotatory-glucose (D-glucose) in liquid phantoms
and in drawn blood based on temporal dynamics of light scattering. The presence of D-glucose alters the medium viscosity,
thus affecting the Brownian motion of the scatterers (polystyrene microspheres (PMS) in phantoms, red blood cells (RBCs) in
blood) as measured by OCT. To quantify the effect, the signal autocorrelation functions were measured from M-mode OCT data
and exponentially fit to obtain the decorrelation times. These were then related to translational (and rotational, in case
of asymmetric scatterers) diffusion coefficients which enabled the determination of D-glucose-controlled medium viscosity.
Obtained viscosily values agreed well with the literature, and showed expected increase with D-glucose concentrations. Whole
blood smears were imaged with microscope and another effect of added glucose, that of red blood cell deformation, was also
observed. This phantom and blood OCT study demonstrates the technique’s ability to detect and quantify D-glucose presence
in non-flowing liquid suspensions, and suggests several additional research routes necessary to determine its potential for
in vivo applications. 相似文献
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Ya‐Bin Zhao Brian Mariampillai Dr. David A. Candito Benoît Laleu Mengzhou Li Mark Lautens Prof. 《Angewandte Chemie (International ed. in English)》2009,48(10):1849-1852
They all fall down : The value of domino processes can be greatly enhanced when the possibility exists for one to selectively diverge from a common intermediate. In preliminary studies the dual reactivity of aryl–palladium intermediates is exploited. A diverse array of fluorene and phenanthrene derivatives were synthesized in a rapid and efficient manner (see scheme).
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