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QUANTITATIVE-ANALYSIS OF PERIODIC ANTIPHASE BOUNDARIES BY LATTICE image SIMULTANEOUS

INTERFACE SCIENCE 1995年第1期3卷 5-15页

作者： LOISEAU, A PENISSON, JM PLANES, J OFF NATL ETUD & RECH AEROSP PHYS SOLIDE OM LABF-92322 CHATILLONFRANCE CEA DEPT RECH FONDAMENTALE MAT CONDENSEESP2MSF-38054 GRENOBLEFRANCE

Periodic antiphase boundaries in the intermetallic compound Cu3Pd have been studied by high resolution electron microscopy and image simulation. The intensity profiles across the boundary were recorded and the thickness of the boundary compared to the values deduced from X-ray and neutron diffraction data. It is shown that electron microscopy always minimizes the thickness of the boundary. The possible factors for this discrepancy are analysed and discussed.

关键词： L1(2) STRUCTURE ANTIPHASE BOUNDARY LONG PERIOD STRUCTURES image SIMULATION HREM computer image processing

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THE POINT-SPREAD FUNCTION OF A CONFOCAL MICROSCOPE - ITS MEASUREMENT AND USE IN DECONVOLUTION OF 3-D DATA

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JOURNAL OF MICROSCOPY 1991年第2期163卷 151-165页

作者： SHAW, PJ RAWLINS, DJ Department of Cell Biology John Innes Institute Colney Lane Norwich NR4 7UH U.K.

We have measured the point-spread function (PSF) for an MRC-500 confocal scanning laser microscope using subresolution fluorescent beads. PSFs were measured for two lenses of high numerical aperture - the Zeiss plan-neofluar 63 x water immersion and Leitz plan-apo 63 x oil immersion - at three different sizes of the confocal detector aperture. The measured PSFs are fairly symmetrical, both radially and axially. In particular there is considerably less axial asymmetry than has been demonstrated in measurements of conventional (non-confocal) PSFs. Measurements of the peak width at half-maximum peak height for the minimum detector aperture gave approximately 0.23 and 0.8-mu-m for the radial and axial resolution respectively (4.6 and 15.9 in dimensionless optical units). This increased to 0.38 and 1.5-mu-m (7.5 and 29.8 in dimensionless units) for the largest detector aperture examined. The resulting optical transfer functions (OTFs) were used in an iterative, constrained deconvolution procedure to process three-dimensional confocal data sets from a biological specimen - pea root cells labelled in situ with a fluorescent probe to ribosomal genes. The deconvolution significantly improved the clarity and contrast of the data. Furthermore, the loss in resolution produced by increasing the size of the detector aperture could be restored by the deconvolution procedure. Therefore for many biological specimens which are only weakly fluorescent it may be preferable to open the detector aperture to increase the strength of the detected signal, and thus the signal-to-noise ratio, and then to restore the resolution by deconvolution.

关键词： CONFOCAL MICROSCOPY 3-DIMENSIONAL FLUORESCENCE MICROSCOPY POINT-SPREAD FUNCTION DECONVOLUTION computer image processing

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PROTEOLYTIC CLEAVAGE AND STRUCTURAL TRANSFORMATION - THEIR RELATIONSHIP IN BACTERIOPHAGE-T4 CAPSID MATURATION

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JOURNAL OF SUPRAMOLECULAR STRUCTURE 1979年第1期10卷 1-11页

作者： STEVEN, AC CARRASCOSA, JL UNIV BASEL BIOCTR DEPT MICROBIOL CH-4056 BASEL SWITZERLAND

Giant T4 phage capsoids formed in canavanine-treated cultures [Escherichia coli] infected by phage mutants in genes 21 and 17, respectively, differ with regard to cleavage of the major capsid protein, gp23, and in the fine structure of their hexagonal surface lattices. Quantitative computer processing of electron micrographs shows that the significant differences in capsomer morphology amount to 6 symmetrically placed features present in the uncleaved hexamer but absent after cleavage. These features may be related with the N[amino]-terminal portions of gp23 monomers excised by phage-specific proteolysis. Cleaved 17- giants can be induced to undergo a further structural transformation (expansion). Structural characteristics of partially transformed giant particles give clues about the dynamics of the cleavage and expansion transformations. Both processes appear to be polar, initiating in 1 cap and propagating along the particle. The transition zone of partial cleavage is diffuse, whereas the transition between unexpanded and expanded areas is confined to a narrow band of some 20 nm width.

关键词： virus assembly limited proteolysis conformational change cooperativity electron microscopy optical diffraction computer image processing

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QUANTITATION IN ECHOCARDIOGRAPHY

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CARDIOVASCULAR AND INTERVENTIONAL RADIOLOGY 1987年第6期10卷 316-331页

作者： SKORTON, DJ COLLINS, SM 1. The Cardiovascular Image Processing and Ultrasonic Imaging Laboratories Cardiovascular Center The University of Iowa 52242 Iowa City IA USA2. Department of Internal Medicine The University of Iowa 52242 Iowa City IA USA3. Department of Electrical and Computer Engineering The University of Iowa 52242 Iowa City IA USA4. Department of Radiology The University of Iowa 52242 Iowa City IA USA5. Department of Biomedical Engineering The University of Iowa 52242 Iowa City IA USA

Imaging of the heart is the predominant approach to cardiovascular diagnosis in current practice. Of the wide variety of cardiac imaging techniques available, echocardiography is one of the most widely used. Standard methods of quantitation of M-mode and two-dimensional echocardiograms yield reproducible, accurate measurements of cardiac chamber, wall, and great vessel dimensions. Qualitative analysis of valvular appearance and motion permits the diagnosis of a wide variety of valvular disorders. Doppler echocardiography yields information on blood flow velocity and pattern in the heart and great vessels. Evolving methods of quantitation in echocardiography include computerized image enhancement, computer-assisted border detection, analysis of regional left ventricular contraction, three-dimensional reconstruction, contrast-enhanced echocardiography, ultrasound myocardial tissue characterization, and intraoperative echocardiography. Echocardiography is a dynamic, evolving discipline with the potential of defining cardiac structure, function, blood flow dynamics, myocardial perfusion, and tissue characteristics. Thus, ultrasonography will continue to be of major importance in the diagnosis of cardiac disease.

关键词： computer image processing Doppler echocardiography Echocardiography Quantitative cardiac imaging Ultrasonography

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2dx_merge:: Data management and merging for 2D crystal images

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JOURNAL OF STRUCTURAL BIOLOGY 2007年第3期160卷 375-384页

作者： Gipson, Bryant Zeng, Xiangyan Stahlberg, Henning Univ Calif Davis Coll Biol Sci Davis CA 95616 USA

Electron crystallography of membrane proteins determines the structure of membrane-reconstituted and two-dimensionally (2D) crystallized membrane proteins by low-dose imaging with the transmission electron microscope, and computer image processing. We have previously presented the software system 2dx, for user-friendly image processing of 2D crystal images. Its central component 2dx_image is based on the MRC program suite, and allows the optionally fully automatic processing of one 2D crystal image. We present here the program 2dx_merge, which assists the user in the management of a 2D crystal image processing project, and facilitates the merging of the data from multiple images. The merged dataset can be used as a reference to re-process all images, which usually improves the resolution of the final reconstruction. image processing and merging can be applied iteratively, until convergence is reached. 2dx is available under the GNU General Public License at http://***. (c) 2007 Elsevier Inc. All rights reserved.

关键词： 2dx software electron crystallography 2D crystals membrane protein structure determination computer image processing MRC software merging

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EVALUATION OF CATHETERS AND METALLIC CATHETER MARKERS AS CALIBRATION STANDARD FOR MEASUREMENT OF CORONARY DIMENSION

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CATHETERIZATION AND CARDIOVASCULAR DIAGNOSIS 1990年第3期21卷 148-153页

作者： LEUNG, WH DEMOPULOS, PA ALDERMAN, EL SANDERS, W STADIUS, ML STANFORD UNIV MED CTR DIV CARDIOL H2321 STANFORD CA 94305 USA

Measurement of coronary dimension requires an accurate and reproducible dimensional reference. Angiographic catheters are frequently used for this purpose. We measured the angiographic diameters of a broad range of diagnostic and angioplasty guiding catheters by using two commonly used edge-detection algorithms. Angiographic diameters are significantly less than true catheter outer diameter. Therefore the use of contrast-filled catheters as a dimensional reference may lead to considerable error in vessel measurement with overestimation of absolute dimension. Tables of reference values for multiple catheters are included. We also evaluated the suitability of a metallic-tipped "marker" catheter as calibration standard, tested under a variety of angiographic conditions. The metallic-tipped marker was found to have a better degree of reproducibility than catheters. These findings have implications for studies employing serial measurements of coronary artery dimension and for the clinical practice of estimating vessel diameter for choice of balloon size during angioplasty.

关键词： coronary quantitation coronary arteriography coronary catheters computer image processing

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Semi-automatic stereotactic coordinate identification algorithm for routine localization of Deep Brain Stimulation electrodes

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JOURNAL OF NEUROSCIENCE METHODS 2010年第1期187卷 114-119页

作者： Hebb, Adam O. Miller, Kai J. Univ Washington Dept Neurosurg Seattle WA 98195 USA

Deep Brain Stimulation (DBS) is a routine therapy for movement disorders, and has several emerging indications. We present a novel protocol to define the stereotactic coordinates of metallic DBS implants that may be routinely employed for validating therapeutic anatomical targets. Patients were referred for troubleshooting or new DBS implantation. A volumetric MRI of the brain obtained prior to or during this protocol was formatted to the Anterior Commissure-Posterior Commissure (AC-PC) coordinate system. Patients underwent a CT scan of the brain in an extended Hounsfield unit (EHU) mode. A semi-automatic detection algorithm based on a Normalized Mutual Information (NMI) co-registration method was implemented to measure the AC-PC coordinates of each DBS contact. This algorithm was validated using manual DBS contact identification. Fifty MRI-CT image pairs were available in 39 patients with a total of 336 DBS electrodes. The median and mean Euclidean distance errors for automatic identification of electrode locations were 0.20 mm and 0.22 mm, respectively. This method is an accurate method of localization of active DBS contacts within the sub-cortical region. As the investigational indications of DBS expand, this method may be used for verification of final implant coordinates, critical for understanding clinical benefit and comparing efficacy between subjects. (C) 2010 Elsevier B.V. All rights reserved.

关键词： Deep Brain Stimulation Movement disorders computer image processing Extended Hounsfield unit Computed Tomography Magnetic Resonance imaging Stereotaxy computerized image analysis

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BINDING OF A SYNTHETIC TARGETING PEPTIDE TO A MITOCHONDRIAL CHANNEL PROTEIN

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JOURNAL OF BIOENERGETICS AND BIOMEMBRANES 1992年第1期24卷 55-61页

作者： MANNELLA, CA GUO, XW DIAS, J SUNY ALBANY SCH PUBL HLTHDEPT BIOMED SCIALBANYNY 12201

Membrane crystals of the mitochondrial outer membrane channel VDAC (porin) from Neurospora crassa were incubated with a 20-amino-acid synthetic peptide corresponding to the N-terminal targeting region of subunit IV of cytochrome oxidase. The peptide caused disordering and contraction of the crystal lattice of the membrane arrays. Also, new stain-excluding features were observed on the peptide-treated arrays which most likely correspond to sites at which the peptide accumulates. The stain exclusion zones associated with binding of the targeting peptide (and with binding of apocytochrome c in an earlier study) have been localized on a two-dimensional density map of frozen-hydrated, crystalline VDAC previously obtained by cryo-electron microscopy. The results indicate that both the peptide and cytochrome c bind to protein "arms" which extend laterally between the channel lumens. The finding that imported polypeptides bind to a specific region of the VDAC protein implicates this channel in the process by which precursor proteins are recognized at and translocated across the mitochondrial outer membrane.

关键词： MITOCHONDRIAL CHANNELS MITOCHONDRIAL TARGETING SEQUENCES ELECTRON MICROSCOPY computer image processing

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APPLICATIONS OF CONFOCAL MICROSCOPY TO THE STUDY OF MYELIN DEVELOPMENT AND NEURON STRUCTURE

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JOURNAL OF ELECTRON MICROSCOPY TECHNIQUE 1991年第1期18卷 31-37页

作者： STAUGAITIS, SM ROWAN, T SANES, DH COLMAN, DR SMITH, PR NYU MED CTR DEPT CELL BIOL 550 1ST AVE NEW YORK NY 10016 USA NYU MED CTR DEPT OTOLARYNGOL NEW YORK NY 10016 USA COLUMBIA UNIV COLL PHYS & SURG DEPT ANAT & CELL BIOL NEW YORK NY 10032 USA COLUMBIA UNIV COLL PHYS & SURG DEPT PATHOL NEW YORK NY 10032 USA

Confocal laser scanning microscopy has been used to study the localization of myelin basic proteins expressed in nonglial cells, and to probe the three-dimensional structure of central auditory neurons in the lateral superior olive. The paper focuses on the techniques used to obtain the results. The key roles of confocal microscopy and computer image processing of the images obtained are emphasized as they relate to the discovery of essential structural information about these specimens.

关键词： MYELIN BASIC PROTEIN LSO NEURONS computer image processing

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Automatic lattice determination for two-dimensional crystal images

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JOURNAL OF STRUCTURAL BIOLOGY 2007年第3期160卷 353-361页

作者： Zeng, Xiangyan Gipson, Bryant Zheng, Zi Yan Renault, Ludovic Stahlberg, Henning Univ Calif Davis Coll Biol Sci Davis CA 95616 USA

Electron crystallography determines the structure of membrane proteins and other periodic samples by recording either images or diffraction patterns. computer processing of recorded images requires the determination of the reciprocal lattice parameters in the Fourier transform of the image. We have developed a set of three programs 2dx_peaksearch, 2dx_findlat and 2dx_getlat, which can determine the reciprocal lattice from a Fourier transformation of a 2D crystal image automatically. 2dx_peaksearch determines a list of Fourier peak coordinates from a processed calculated diffraction pattern. These coordinates are evaluated by 2dx_findlat to determine one or more lattices, using a-priori knowledge of the real-space crystal unit cell dimensions, and the sample tilt geometry. If these are unknown, then the program 2dx_getlat can be used to obtain a guess for the unit cell dimensions. These programs are available as part of the 2dx software package for the image processing of 2D crystal images at http://***. (c) 2007 Elsevier Inc. All rights reserved.

关键词： electron crystallography 2D membrane protein crystals computer image processing lattice determination

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