Diffuse and nonlinear imaging of multiscale vascular parameters for in vivo monitoring of preclinical mammary tumors

Diffuse optical imaging (DOI) techniques provide a wide‐field or macro assessment of the functional tumor state and have shown substantial promise for monitoring treatment efficacy in cancer. Conversely, intravital microscopy provides a high‐resolution view of the tumor state and has played a key role in characterizing treatment response in the preclinical setting. There has been little prior work in investigating how the macro and micro spatial scales can be combined to develop a more comprehensive and translational view of treatment response. To address this, a new multiscale preclinical imaging technique called diffuse and nonlinear imaging (DNI) was developed. DNI combines multiphoton microscopy with spatial frequency domain imaging (SFDI) to provide multiscale data sets of tumor microvascular architecture coregistered within wide‐field hemodynamic maps. A novel method was developed to match the imaging depths of both modalities by utilizing informed SFDI spatial frequency selection. An in vivo DNI study of murine mammary tumors revealed multiscale relationships between tumor oxygen saturation and microvessel diameter, and tumor oxygen saturation and microvessel length (|Pearson's ρ| ≥ 0.5, P < 0.05). Going forward, DNI will be uniquely enabling for the investigation of multiscale relationships in tumors during treatment.      

Single-pad scheme for integrated optical fluorescence sensing

A new scheme for integrated optical fluorescence sensing is presented. The principle is based on a planar waveguide containing multiple sensing units, each consisting of a single-pad grating coupler structure. Single-pad means that all the following functions are incorporated in one single pad: laser light input, excitation of the labeled analyte molecules, efficient collection of the emitted fluorescent light into the waveguide, background suppression, and coupling the guided wave out to the detector. The results demonstrate a high efficiency of the fluorescence light excitation and collection, as well as a good suppression of the volume background.     

A moss “canopy” – Small-scale differences in microclimate and physiological traits in Tortula ruralis

We studied vertical changes in light regime and water content (WC) in combination with vertical gradients in several physiological response variables, i.e. net CO₂ uptake, chlorophyll content and nitrogen content in the moss species, Tortula ruralis. The rate of light attenuation within the moss turf, which was determined with a custom-made optical microprobe system, was strongly dependent on plant WC. Curling movements of the upper leaves associated with the beginning desiccation of the uppermost parts of a turf allowed increased penetration of light to greater depth with decreasing WC. The capacity to fix carbon declined steeply with depth: below ca. 9 mm no net CO₂ uptake occurred, even when removing the shading parts above. The potential rates of photosynthesis in different depths were highly correlated with chlorophyll content, but not nitrogen content.     

A fibre optic catheter for simultaneous measurement of longitudinal and circumferential muscular activity in the gastrointestinal tract

Diagnostic catheters based on fibre Bragg gratings (FBG's) are proving to be highly effective for measurement of the muscular activity associated with motility in the human gut. While the primary muscular contractions that generate peristalsis are circumferential in nature, it has long been known that there is also a component of longitudinal contractility present, acting in harmony with the circumferential component to improve the overall efficiency of material movement. We report the detection of longitudinal motion in mammalian intestine using an FBG technique that should be viable for similar detection in humans. The longitudinal sensors have been combined with our previously reported FBG pressure sensing elements to form a composite catheter that allows the relative phase between the two components to be detected. The catheter output has been validated using video mapping in an ex‐vivo rabbit ileum preparation. (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Functional morphology and light-gathering ability of podocopid ostracod eyes and the palaeontological implications

The optical features of lateral ocelli of the eye were examined in 29 Recent species of the major ostracod group Podocopida using a theoretical morphological model. A cuticular lens–tapetum model was used for this purpose. Ray tracing was simulated on each model in order to assess the light-gathering abilities of the various forms of eyes. The results of computer simulations and morphospace analyses indicated that the light-gathering ability of the eye is dominantly affected by the thickness and curvature of the outer surface of the lens. On the basis of a combination of form and light-gathering ability, four eye types (LG1, LG2, MG, and HG) were recognized. The results of the phototactic experiment and the light intensity from each microhabitat were concordant with estimated scores on the light-gathering abilities using the theoretical models. Phylogenetic analyses and the fossil record indicate that the MG type is the most plesiomorphic, and that the other types derive from this. The present study also suggests that the optical structure that determines the light-gathering ability is closely related to the development of surface ornamentation on the valve.  © 2006 The Linnean Society of London, Zoological Journal of the Linnean Society , 2006, 147 , 97–108.     

Synthesis, characterization and crystal structure of the bimetallic cyano-bridged [(η-C5H5)(PPh3)2Ru(μ-CN)Ru(PPh3)2(η-C5H5)][PF6]

The bimetallic cyano-bridged [(η⁵-C₅H₅)(PPh₃)₂Ru(μ-CN)Ru(PPh₃)₂(η⁵-C₅H₅)][PF₆] (1) was prepared by reaction of [(η⁵-C₅H₅)(PPh₃)₂RuCl] with N,N′-bis(cyanomethyl)ethylenediamine. The single crystal structure determined by X-ray diffraction showed crystallization on the triclinic P1 space group with a perfect alignment of the cyanide bridges. This accentric crystallization was explored having in view the NLO properties at the macroscopic level, determined by the Kurtz Powder technique. Besides the very low efficiency values for the second harmonic generation, the value obtained for the bimetallic complex 1 showed to be higher than one of the parent complex [(η⁵-C₅H₅)(PPh₃)₂RuCN] (2).     

基于自适应光学的视网膜单细胞光学相干层析成像技术

介绍了一种基于CCD相机的并行光学相干层析成像技术,将所建立的层析成像系统和自适应光学视网膜相机结合。利用一维光学相干层析系统对人眼视网膜进行追踪并控制相干门在视网膜内的位置,利用基于CCD相机的二维光学相干层析成像系统记录视网膜的干涉图像。用眼模型和牛眼视网膜组织对系统进行了测试,通过将4幅干涉图像的获取时间控制在7 ms以内来减少视网膜运动对成像的影响;系统的轴向点扩展函数和灵敏度分别达到10 μm和76 dB。实验结果表明,所建立的基于自适应光学的视网膜光学相干层析成像系统的空间分辨率和灵敏度远远高于其它基于自适应光学的视网膜成像技术。     

Second order molecular nonlinearities in new orthopalladated push-pull chromophores

Three new orthopalladated chromophores based on push-pull π conjugated ligands have been prepared and characterized. The second order molecular NLO activity has been determined by EFISH measurements giving μ_gβ values up to 610×10⁻⁴⁸ esu at an incident laser wavelength of 1.907 μm. The X-ray structures of two different polymorphs of one chromophore are also reported and polymorphism is discussed in terms of conformational changes.     

Optical Feedback Loop Involving Dinoflagellate Symbiont and Scleractinian Host Drives Colorful Coral Bleaching

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Polarization‐multiplexed,dual‐beam swept source optical coherence tomography angiography

A polarization‐multiplexed, dual‐beam setup is proposed to expand the field of view (FOV) for a swept source optical coherence tomography angiography (OCTA) system. This method used a Wollaston prism to split sample path light into 2 orthogonal‐polarized beams. This allowed 2 beams to shine on the cornea at an angle separation of ~14°, which led to a separation of ~4.2 mm on the retina. A 3‐mm glass plate was inserted into one of the beam paths to set a constant path length difference between the 2 polarized beams so the interferogram from the 2 beams are coded at different frequency bands. The resulting OCTA images from the 2 beams were coded with a depth separation of ~2 mm. A total of 5 × 5 mm² angiograms from the 2 beams were obtained simultaneously in 4 seconds. The 2 angiograms then were montaged to get a wider FOV of ~5 × 9.2 mm².