Polarization contrast imaging of biological tissues by polarization-sensitive Fourier-domain optical coherence tomography

Jones matrix imaging of biological samples by a polarization-sensitive Fourier-domain optical coherence tomography has been demonstrated using a two-dimensional CCD camera to obtain two spectra corresponding to the orthogonal polarization components simultaneously. The measurement results of a quarter-wave plate are compared between the two incident polarization sets, H-V linear and R-L circular polarization. Jones matrix imaging of the bovine tendon is demonstrated. Measured Jones matrix images are converted to equivalent Müller matrix images. Local polarization properties are obtained by longitudinal differentiation of Jones matrix components. The layered structure of the bovine tendon and birefringence are revealed.     

Participation of cysteine protease cathepsin L in the gel disintegration of red bulleye (Priacanthus macracanthus) surimi gel paste

BACKGROUND: Endogenous proteases, among them cysteine‐type proteases, are reported to contribute to gel disintegration, resulting in kamaboko of poor quality. Severe gel disintegration occurs in red bulleye surimi gel paste. The objective of this study was to clarify the participation of cysteine protease cathepsin L in the gel disintegration of red bulleye surimi. The surimi was made into kamaboko with and without cathepsin L inhibitors. To confirm its hydrolysis action, crude cathepsin L was also extracted and added to the surimi to make kamaboko. RESULTS: The gel strength of kamaboko obtained by both one‐step (50 °C, 2 h) and two‐step (50 °C, 2 h + 80 °C, 20 min) heating was very low in the absence of inhibitors. Protease inhibitors E‐64 and leupeptin were found to enhance the gel strength considerably. Sodium dodecyl sulfate polyacrylamide gel electrophoresis revealed that the hydrolysis of kamaboko was promoted by crude cathepsin L and inhibited by E‐64 and leupeptin. The gel strength of two‐step heated kamaboko was increased from 12 to 110 and 130 g cm^?2 by E‐64 and leupeptin respectively at a concentration of 0.2 g kg^?1 surimi. CONCLUSION: Endogenous cathepsin L of red bulleye surimi participates in gel disintegration during kamaboko processing. It does so by degrading the myosin heavy chain of actomyosin and consequently hindering the gelation of red bulleye surimi. Copyright © 2009 Society of Chemical Industry     

Production of Monopolar Ions from Streamer Coronas Induced by Very Short Pulse Voltage

The initial and time-dependent concentration of ions in the streamer coronas produced by very short pulse voltages with a half-tail of 100-500 as are measured under the condition that a dc bias voltage is applied between the corona and plate electrodes. The waveform of the corona current of both positive and negative polarities indicates that, although the plasma formation is made in a very short time of about 10 ns, the ionic current flowing across the electrode gap has a very long duration time of 1-3 ms. This is due to the slow processes of ion recombination and migration. The theoretical model of the ion separation process for production of monopolar ionic current is presented and confirmed by the experimental results. The initial ion concentration in these streamer coronas amounts to (5-6) x 109 ion paires/cm3 for both negative and positive streamers.     

Image similarity based on Discrete Wavelet Transform for robots with low-computational resources

This paper describes a similarity measure for images which can be used in image-based topological localization and topological SLAM problems by autonomous robots with low computational resources. Instead of storing the images in the robot’s memory, we propose a compact signature to be extracted from the images. The signature is based on the calculation of the 2D Haar Wavelet Transform of the gray-level image and its size is only 170 bytes. We called this signature the DWT-signature. We exploit the frequency and space localization property of the wavelet transform to match the images grabbed by the perspective camera mounted on board the robot and the reference panoramic images built using an automatic image stitching procedure. The proposed signature allows, at the same time, memory saving and fast and efficient similarity calculation. For the topological SLAM problem we also present a simple implementation of a loop-closure detection based on the proposed signature.We report experiments showing the effectiveness of the proposed image similarity measure using two kinds of small robots: an AIBO ERS-7 robot of the RoboCup Araibo Team of the University of Tokyo and a Kondo KHR-1HV humanoid robot of the IAS-Lab of the University of Padua.     

翼型失速特性的RANS方法与DES方法数值模拟对比分析

RAN S(R eyno lds-averaged N av ier-Stokes)加湍流模型是当前计算飞机粘性流场的最常用方法,数值实践说明要计算大分离流动,需要更高级的方法例如LES(Large Eddy S im u lation)或DN S(D irect N S S im u lation)。然而实际雷诺数下,LES和DN S对网格的要求太高,以至目前还难以应用。DES(D etached-Eddy S im u lation)方法结合了RAN S和LES的优点,通过对Spalart-A llm aras湍流模型中长度尺度的修正,在近壁面它体现为RAN S模型的特点,而在远离物面处又保持LES的亚格子模型的特性。论文对比了采用RAN S和DES方法数值模拟翼型失速特性的能力,并与实验结果进行了对比。结果表明,对大分离流动的数值模拟,DES方法体现出更强的能力。     

A novel micromixer with three‐dimensionally cross‐linked capillary array structure fabricated by deep X‐ray lithography

A novel micromixer was proposed, fabricated and verified. The new concept of the micromixer is to cross‐link many capillaries in a three‐dimensional structure. The characteristic flow behaviors were simulated by using the “FLUENT” computational fluid dynamics (CFD) software. The results of the CFD showed unique mixing behavior in three‐dimensionally cross‐linked capillaries. The mixing performance of the micromixer is strongly influenced by controlling the three‐dimensional crossing conditions. The micromixer was fabricated by deep X‐ray lithography with multistep exposure. The cross‐linked capillary structures were successfully fabricated while controlling the cross‐link conditions. The performance of the micromixer was evaluated by using an enzyme reaction. By comparing the mixtures produced with a cross‐linked fluid filter and with a fluid filter without cross‐linked capillaries, we found that the reaction was accelerated by using the new micromixer. © 2011 Wiley Periodicals, Inc. Electr Eng Jpn, 177(1): 26–31, 2011; Published online in Wiley Online Library ( wileyonlinelibrary.com ). DOI 10.1002/eej.21157     

Generation of polyacetylene sulfoxide radicals through spin migration from the main-chain to the sulfoxide moiety in the side chain of poly[p-(n-butylsulfoxide)phenylacetylene] prepared with a [Rh(norbornadiene)Cl]2 catalyst

A phenylacetylene bearing an n-butylsulfoxide group, i.e., p-(n-butylsulfoxide)phenylacetylene (1) was prepared in high yields using the [Rh(norbornadiene)Cl]₂-NEt₃ catalyst in the presence of various solvents under mild conditions. The resulting polymer, poly[p-(n-butylsulfoxide)phenylacetylene] (poly(1)), was characterized in detail by ¹H NMR, ESR, laser Raman, and diffuse reflective UV-vis methods. The data clearly showed that cis-to-trans isomerization of the polymer can be induced when pressure is imposed to the polymer at room temperature, rotationally breaking the cis CC bonds to generate the cis and trans radicals. Further, the spin density in the cis radical was migrated from the main-chain to the sulfoxide moiety as the side chain of the phenyl ring to magnetically interact with the first two methylene protons in the n-butyl group giving a triplet line ESR spectrum with an extremely large g value, g = 2.0081.     

Numerical Simulation and Experiment on the Transport of Fine Particles in a Ventilated Room

ABSTRACT

The change in concentration distribution of particulate contaminants emitted in a room was studied experimentally and theoretically to investigate whether the transport of contaminants in a room with a source of particles can be predicted by numerical simulation. Tracer contaminants, monodisperse latex particles, were introduced into a 3.3 m ×2.7 m ×2 m room with clean air for a given time, and the change in the contaminant concentrations with time was measured at various positions in the room. Calculations of the spatial and temporal distributions in the gas velocity and contaminant concentration were performed to predict the concentration change, with the Navier-Stokes and convection-diffusion equations solved numerically. The experimental results showed that the concentration distribution depends on the position of introduction of the contaminants. It was also indicated that the contaminants introduced near the room floor diffuse more than predicted. However, the calculated concentrations agreed almost quantitatively with the measured results, except near the floor and walls. The change in the concentration with time and the dependence of the concentration distribution on the position of the particle source were well reproduced by the calculation.     

Selective hydroxylation of benzene to phenol by photocatalysis of molybdenum complexes grafted on mesoporous FSM‐16

Mo complexes with Mo₁–Mo₄ nuclearities were grafted on mesoporous silica FSM‐16, and their catalytic performances were studied in the hydroxylation of benzene. A trinuclear Mo oxo complex grafted on FSM‐16 exhibits the highest catalytic activity in the hydroxylation of benzene to phenol using hydrogen peroxide as an oxidant under the irradiation of UV‐light. The turnover numbers for phenol are over 700 at 300 K. This revised version was published online in July 2006 with corrections to the Cover Date.     

Two-stage dual fluidized bed gasification: Its conception and application to biomass

The quoted two-stage dual fluidized bed gasification (T-DFBG) devises the use of a two-stage fluidized bed (TFB) to replace the single-stage bubbling fluidized bed gasifier involved in the normally encountered dual fluidized bed gasification (N-DFBG) systems. By feeding fuel into the lower stage of the TFB, this lower stage functions as a fuel gasifier similar to that in the N-DFBG so that the upper stage of the TFB works to upgrade the produced gas in the lower stage and meanwhile to suppress the possible elutriation of fuel particles fed into the freeboard of the lower-stage bed. The heat carrier particles (HCPs) circulated from the char combustor enter first the upper stage of the TFB to facilitate the gas upgrading reactions occurring therein, and the particles are in turn forwarded into the lower stage to provide endothermic heat for fuel pyrolysis and gasification reactions. Consequently, with T-DFBG it is hopeful to increase gasification efficiency and decrease tar content in the produced gas. This anticipation was corroborated through gasifying dry coffee grounds in two 5.0kg/h experimental setups configured according to the principles of T-DFBG and N-DFBG, respectively. In comparison with the N-DFBG case, the test according to T-DFBG increased, the fuel C conversion and cold gas efficiency by about 7% and decreased tar content in the produced gas by up to 25% under similar reaction conditions. Test results demonstrated also that all these upgrading effects via adopting T-DFBG were more pronounced when a Ca-based additive was blended into the fuel.