Image Analysis (image + analysis)

Distribution by Scientific Domains
Distribution within Medical Sciences

Kinds of Image Analysis

  • automate image analysis
  • computer-assisted image analysis
  • computerized image analysis
  • digital image analysis
  • multivariate image analysis
  • quantitative image analysis

  • Terms modified by Image Analysis

  • image analysis approach
  • image analysis method
  • image analysis procedure
  • image analysis program
  • image analysis software
  • image analysis system
  • image analysis technique
  • image analysis techniques
  • image analysis tool

  • Selected Abstracts


    DETECTION OF PERIVASCULAR BLOOD FLOW IN VIVO BY CONTRAST-ENHANCED INTRACORONARY ULTRASONOGRAPHY AND IMAGE ANALYSIS: AN ANIMAL STUDY

    CLINICAL AND EXPERIMENTAL PHARMACOLOGY AND PHYSIOLOGY, Issue 12 2007
    Manolis Vavuranakis
    SUMMARY 1Acute coronary syndromes are mostly the result of coronary plaque rupture. Diagnostic techniques focusing on the early detection of those plaques that are prone to rupture are still limited. Increased neovascularization in the adventitia and within the atherosclerotic plaque have recently been identified as common features of inflammation and plaque vulnerability. Contrast-enhanced intravascular imaging with microbubbles can be used to trace perfusion. 2In the present study, we examined the perivascular network of the left anterior descending coronary arteries and left circumflex arteries of four domestic, clinically healthy pigs using intracoronary ultrasound after injection of microbubbles with a differential imaging technique (ACESÔ; Computational Biomedicine Laboratory, University of Houston, Houston, TX, USA). Our aim was to detect blood flow into the coronary lumen and perivascular flow in contrast-enhanced images. Eleven regions of interest (ROI), including perivascular structures, were compared with regard to their grey scale level before and after the injection of SonoVue® (0.06 mL/kg; Bracco Diagnostics, Princeton, NJ, USA). 3A statistically significant (P = 0.018) enhancement was found in the echogenicity of the total perivascular space (adventitial region and perivascular vessels), as indicated by an increase in grey level intensity from 8.33 ± 0.80 (before) to 10.11 ± 0.88 (after microbubble injection). A significant enhancement of the 11 selected ROI (perivascular structures) was also recorded after the injection of microbubbles (from 7.92 ± 2.14 to 14.03 ± 2.44; P = 0.008). 4We believe that the detection of perivascular structures with contrast-enhanced intracoronary ultrasonography combined with proper image processing may reinforce our future efforts in the detection of vasa vasorum, an active participant in the creation of acute coronary events. [source]


    Roughness Characterization through 3D Textured Image Analysis: Contribution to the Study of Road Wear Level

    COMPUTER-AIDED CIVIL AND INFRASTRUCTURE ENGINEERING, Issue 2 2004
    M. Khoudeir
    The microtexture is defined as surface irregularities whose height ranges from 0.001 mm to 0.5 mm and whose width is less than 0.5 mm (Alvarez and Mprel, 1994). The deterioration due to the road traffic, especially polishing effect, involves a change in the microtexture. So, we suggest a method to characterize, through image analysis, wear level or microroughness of road surfaces. We propose then, on one hand a photometric model for road surface, and, on the other hand, a geometrical model for road surface profile. These two models allow us to develop roughness criteria based on the study of the statistical properties of: the distribution of the gray levels in the image, the distribution of the absolute value of its gradient, the form of its autocorrelation function, and the distribution of its curvature map. Experiments have been done with images of laboratory-made road specimens at different wear levels. The obtained results are similar to those obtained by a direct method using road profiles. [source]


    Assessment of Carotid Compliance Using Real Time Vascular Ultrasound Image Analysis in Marfan Syndrome

    ECHOCARDIOGRAPHY, Issue 4 2009
    Anatoli Kiotsekoglou M.D.
    Background: Fibrillin-1 deficiency, dysregulated cytokine transforming growth factor-,, and increased collagen deposition related to fibrillin-1 gene mutations could predispose to impaired carotid compliance (CC) in Marfan syndrome (MFS). We sought to detect any alterations in CC using the vascular image analysis system (VIA). Methods and Results: Thirty-two MFS patients, 20 men and 12 women (mean age 34.2 ± 12.05 years), and 29 controls matched for age, sex, and body surface area (BSA) were recruited. The entire length of each carotid system was initially scanned longitudinally using a 14 MHz linear transducer. Then, a stereotactic clamp held the transducer in contact with the carotid artery. Arterial diameter changes during the cardiac cycle were recorded for 1 minute from both right (RCCA) and left common carotid arteries (LCCA) separately using the VIA system. RCCA and LCCA compliance and distensibility measurements were significantly reduced in MFS patients when compared to controls, P < 0.05. RCCA and LCCA intima-media thickness did not differ between patients and controls, P > 0.05. MFS diagnosis and age were associated with reduced CC in both carotid arteries after adjusting for variables such as, sex, BSA, heart rate, beta-blockade, intima-media thickness, and aortic root size. Conclusions: Our findings showed a reduction in CC in adult patients with MFS. This could be attributed to fibrillin-1 deficiency resulting in structural abnormalities in the carotid arterial wall. [source]


    Quantitative Image Analysis in Darmstadt

    IMAGING & MICROSCOPY (ELECTRONIC), Issue 3 2007
    Konrad Sandau Prof. Dr.
    The 14th workshop "Quantitative Image Analysis" has been held at the University of Applied Sciences in Darmstadt on 15 June 2007. Image Analysis works on complex images as 3D-images, massive mosaics and video sequences. [source]


    Image Analysis Based Quantification of Bacterial Volume Change with High Hydrostatic Pressure

    JOURNAL OF FOOD SCIENCE, Issue 9 2008
    M. Pilavtepe-Çelik
    ABSTRACT:, Scanning electron microscopy (SEM) images of Staphylococcus aureus 485 and Escherichia coli O157:H7 933 were taken after pressure treatments at 200 to 400 MPa. Software developed for this purpose was used to analyze SEM images and to calculate the change in view area and volume of cells. Significant increase in average cell view area and volume for S. aureus 485 was observed in response to pressure treatment at 400 MPa. Cell view area for E. coli O157:H7 933 significantly increased at 325 MPa, the maximum pressure treatment tested against this pathogen. In contrast to S. aureus, cells of E. coli O157:H7 exhibited significant increase in average view area and volume at 200 MPa. The pressure-induced increase in these parameters may be attributed to modifications in membrane properties, for example, denaturation of membrane-bound proteins and pressure-induced phase transition of membrane lipid bilayer. [source]


    Image analysis and morphometry in the diagnosis of breast cancer

    MICROSCOPY RESEARCH AND TECHNIQUE, Issue 2 2002
    Joan Gil
    Abstract Image Analysis, a complicated field still in the early stages of application to Pathology, has the capability of rendering major contributions to the diagnosis, prognosis, and management of malignancies of the breast. The present review summarizes the main problems and the general approach to the use of this technique for quantitating immunohistochemical stain results, obtaining DNA histograms, and making de novo diagnoses in routine materials of the Pathology service. In the case of diagnosis, the main steps are sampling, segmentation, and measures of chromatin texture. Currently, the limiting factor for all routine applications of image analysis is probably the absence of a reliable automatic nuclear segmentation. Microsc. Res. Tech. 59:109,118, 2002. © 2002 Wiley-Liss, Inc. [source]


    Crystal Shape Characterisation of Dry Samples using Microscopic and Dynamic Image Analysis

    PARTICLE & PARTICLE SYSTEMS CHARACTERIZATION, Issue 4 2009
    Kumar Patchigolla
    Abstract A standard method to determine particle shape and size is by image analysis. This paper addresses microscopic image analysis (semi-automated) investigations of two different organic crystalline chemicals generated by batch cooling crystallisation. The results generated from microscopic image analysis were compared with data obtained by dynamic image analysis (automated) because very few contributions are available in the open literature. The chemical systems were polymorphic L-glutamic acid which crystallises into , (prismatic) or , (needle) form and the non-polymorphic mono sodium glutamate which crystallises into needles. The images from these techniques were processed to generate information on crystal shape and size. It has been observed that shape effects can distort the size obtained in size characterization studies. In this study, comparisons were made of processing time, number of crystals and accuracy between microscopic and dynamic image analysis. For representative microscopic image analysis, 5000 crystals were analysed in an average of eight hours while several hundred thousand crystals were processed using dynamic image analysis within 15 minutes. Using the parameters D10, D50, D90, span and aspect ratio for statistical comparison, it was found that the results obtained for D50 by the two techniques were comparable and in accordance with other measurements (laser diffraction spectroscopy and ultrasonic attenuation spectroscopy) even though these non-spherical particles had different orientations during measurement by the two methods. However, substantial differences in span of the distribution and aspect ratio were returned by the two techniques. [source]


    Assessment of Proliferating Cell Nuclear Antigen Activity Using Digital Image Analysis in Breast Carcinoma Following Magnetic Resonance-Guided Interstitial Laser Photocoagulation

    THE BREAST JOURNAL, Issue 5 2003
    Soheila Korourian MD
    Abstract: This study examines proliferative activity in tumor cells of patients with histologically documented invasive breast carcinoma treated with magnetic resonance-guided interstitial laser photocoagulation (MR-GILP). Immunohistochemical marker for proliferating cell nuclear antigen (PCNA), a nuclear protein abundant in actively proliferating cells, is used. The study demonstrates the effectiveness of MR-GILP in ablating tumor cells of infiltrating breast cancer. The diagnosis of infiltrating breast carcinoma was confirmed by core needle biopsies. Using a specially designed magnetic resonance imaging (MRI) device, rotating delivery of excitation off-resonance (RODEO), tumors were measured ranging from 1.8 to 4.0 cm in greatest dimension. Seven formalin-fixed, paraffin-embedded archival tissues from seven patients with infiltrating carcinoma, status post-MR-GILP, were analyzed. Using PCNA immunoperoxidase (Biomeda Corp.), the proliferative capability of the remaining tumor cells around the focus of laser photocoagulation was determined. The lesions were digitally acquired using a Nikon Eclipse E800 microscope with an automated stage. Images were analyzed using Cool SNAP image editing software (version 1.0). Appropriate thresholds were set for positive staining and limited concentric radial measurements of equal area between all samples were compared at radial millimeter intervals from the center of laser ablation. The integrated area occupied by PCNA-positive cells per radial millimeter from the charcoal site (the center of the laser) increased as the distance from this site increased (a mean average at each radial measurement revealed: at the 1 mm radius the positive integrated area was 0.0024 mm2; at 2 mm, 0.0145 mm2; at 3 mm, 0.0351 mm2; at 4 mm, 0.0696 mm2; at 5 mm, 0.1025 mm2; and at 6 mm, 0.1263 mm2). MR-GILP is an effective mean of ablating breast carcinoma. This treatment option may represent an alternative to lumpectomy for a single lesion ,1 cm, or make patients with two separate lesions eligible for lumpectomy. [source]


    Investigation into the hydrodynamics of gas,solid fluidized beds using particle image velocimetry coupled with digital image analysis

    THE CANADIAN JOURNAL OF CHEMICAL ENGINEERING, Issue 3 2008
    Jan Albert Laverman
    Abstract The hydrodynamics of a freely bubbling, pseudo 2-D fluidized bed has been investigated experimentally for different bed aspect ratios at different superficial gas velocities by using Particle Image Velocimetry (PIV) combined with Digital Image Analysis (DIA). Coupling of both non-invasive measuring techniques allows us to obtain information on both the bubble behaviour and emulsion phase circulation patterns simultaneously. In particular, the combination of DIA with PIV allows to correct for the influence of particle raining through the roof of the bubbles on the time-averaged emulsion phase velocity profiles. On a étudié de façon expérimentale l'hydrodynamique d'un lit fluidisé pseudo 2-D en bouillonnement libre, pour différents rapports de forme de lits à différentes vitesses de gaz superficielles par vélocimétrie à images de particules (PIV) combinée à l'analyse d'images numériques (DIA). Le couplage de deux techniques de mesure non invasives nous permet d'obtenir de l'information sur le comportement des bulles et les schémas de circulation de la phase d'émulsion, simultanément. En particulier, la combinaison de DIA et de PIV permet de corriger l'influence de la pluie de particules s'écoulant du toit de bulles sur les profils de vitesse de la phase d'émulsion moyennés dans le temps. [source]


    Climatic influence on the inter-annual variability of late-Holocene minerogenic sediment supply in a boreal forest catchment

    EARTH SURFACE PROCESSES AND LANDFORMS, Issue 4 2010
    Gunilla Petterson
    Abstract Processes controlling sediment yield vary over a range of timescales, although most process-based observations are extremely short. Lake sediments, however, can be used to extend the observational timescale and are particularly useful when annually laminated (varved) sediment is present. The sediment record at Kassjön (N. Sweden) consists of ,6400 varves, each 0·5,1 mm thick. Image analysis was used to determine grey-scale variation and varve thickness from which annual minerogenic accumulation rate (MinAR) (mg cm,2 year,1) was inferred for the period 4486 BC , AD 1900. MinAR varies on annual to centennial scales and mainly reflects channel bank erosion by the inflow streams. The mineral input reflects the intensity of the spring run-off, which is dependent on the amount of snow accumulated during the winter, and hence MinAR is a long-term record of variability in past winter climate; other factors will be a variable response to catchment uplift, vegetation succession and pedogenesis. A major shift from low to high MinAR occurred ,250 BC, and peaks occurred around AD 250, 600, 1000, 1350 and 1650. Wavelet power spectrum analysis (confirmed by Fourier analyses) indicated significantly different periodicities throughout the period 4000 BC , AD 1700, including 275 years for the period 4000 BC , 2900 BC, 567 years for the period 2901 BC , 1201 BC, and 350 and 725 years for the period 1200 BC , AD 1700. The long-term, centennial scale variability (,350 years) may reflect solar forcing (cf the 385-year peak in tree-ring calibrated 14C activity) but interestingly, there is no obvious link to high frequency forcing, such as the North Atlantic Oscillation. The high resolution component of the record highlights the relevance of varved lake sediment records for understanding erosion dynamics in undisturbed forested catchments and their link to long-term climate dynamics and future climate change. Copyright © 2010 John Wiley & Sons, Ltd. [source]


    Epifluorescence microscopy and image analysis of high-level polycyclic aromatic hydrocarbon contamination in soils

    ENVIRONMENTAL TOXICOLOGY & CHEMISTRY, Issue 12 2006
    J. Chadwick Roper
    Abstract Interactions between polycyclic aromatic hydrocarbons (PAHs) and soil are an important determinant of their chemical availability and transport. Laboratory examination of microscale PAH,soil interaction is limited by the availability of methods for particle-scale observation. Inverted epifluorescence microscopy, combined with digital photography and computer image analysis, was evaluated for specificity and linearity using dissolved PAHs. A pyrene filter (excitation wavelength, 360,400 nm; emission wavelength, 450,520 nm) gave nonspecific PAH fluorescence, and bias for fluoranthene, benzo[b]fluoranthene, benzo[g, h, i]perylene, and benz[a]anthracene was quantified in comparison to that for pyrene. Concentrations ranging from 1 to 10 mM for anthracene, fluoranthene, and pyrene and from 1 to 50 mM for naphthalene produced a linear response with low interpixel variability. Liquid-phase analyses validated use of the technique for the descriptive analysis of PAH distribution in solid samples, but liquid-phase calibration was not quantitative for spiked or field-contaminated soils. The mean luminance for three field soils was proportional to the values predicted from their chemically measured concentrations and to values from spiked, aged, uncontaminated materials. Image analysis of laboratory- and field-contaminated samples determined the area distribution of fluorescent intensity and the size of fluorescent areas exceeding a threshold luminance. These qualitative descriptions of the microscale spatial distribution of PAH contamination are presented as potential endpoints for future research on biogeochemical interactions in heavily contaminated solids. [source]


    Image analysis to reveal crack development using a computer simulation of wear and rolling contact fatigue

    FATIGUE & FRACTURE OF ENGINEERING MATERIALS AND STRUCTURES, Issue 10 2003
    D. I. FLETCHER
    ABSTRACT Plastic flow of near-surface rail material under contact loading is a feature of rail,wheel contact, and severe flow typically leads to both wear, and the initiation and development of small surface-breaking cracks. This paper presents results from a ratcheting based computer simulation, which has been developed to allow the simultaneous investigation of wear, crack initiation and early crack propagation. To identify repeatably small crack-like flaws, image analysis is applied to the visual representation of the wearing surface generated by the model. This representation shows a good similarity to traditional micrographs taken from sections of worn surfaces. The model clearly reveals the interaction of wear with crack development, processes which are linked because wear truncates surface-breaking cracks, and can completely remove small surface-breaking cracks. [source]


    Image analysis of Daphnia populations: non-destructive determination of demography and biomass in cultures

    FRESHWATER BIOLOGY, Issue 10 2002
    Per J. Færøvig
    SUMMARY 1. An image analysis technique was developed for the semiautomatic determination of abundance, size distribution and biomass in Daphnia cultures. This allowed detailed observations of growth, demography and biomass accumulation in live populations, avoiding artifacts caused by subsampling and sampling losses. 2. The image analysis method gave fast, non-destructive and reliable individual counts, even in cultures with high density and a large fraction of juveniles. 3. In Daphnia, animal width changes with nutritional status and growth within instar, while length changes only at the moult. Thus, estimation of individual biomass using an ellipsoidal model based on animal width gave improved biomass calculations compared to manual counting, sizing, and length : weight regressions. 4. The power of the image analysis technique for assessing population growth and size structure was demonstrated in two 40-day experiments, with Daphnia magna feeding on the green algae Selenastrum capricornutum in a two-stage chemostat system. [source]


    Use of image analysis techniques for objective quantification of the efficacy of different hair removal methods

    INTERNATIONAL JOURNAL OF COSMETIC SCIENCE, Issue 2 2007
    S. Bielfeldt
    In the field of consumer-used cosmetics for hair removal and hair growth reduction, there is a need for improved quantitative methods to enable the evaluation of efficacy and claim support. Optimized study designs and investigated endpoints are lacking to compare the efficacy of standard methods, like shaving or plucking, with new methods and products, such as depilating instruments or hair-growth-reducing cosmetics. Non-invasive image analysis, using a high-performance microscope combined with an optimized image analysis tool, was investigated to assess hair growth. In one step, high-resolution macrophotographs of the legs of female volunteers after shaving and plucking with cold wax were compared to observe short-term hair regrowth. In a second step, images obtained after plucking with cold wax were taken over a long-term period to assess the time, after which depilated hairs reappeared on the skin surface. Using image analysis, parameters like hair length, hair width, and hair projection area were investigated. The projection area was found to be the parameter most independent of possible image artifacts such as irregularities in skin or low contrast due to hair color. Therefore, the hair projection area was the most appropriate parameter to determine the time of hair regrowth. This point of time is suitable to assess the efficacy of different hair removal methods or hair growth reduction treatments by comparing the endpoint after use of the hair removal method to be investigated to the endpoint after simple shaving. The closeness of hair removal and visible signs of skin irritation can be assessed as additional quantitative parameters from the same images. Discomfort and pain rating by the volunteers complete the set of parameters, which are required to benchmark a new hair removal method or hair-growth-reduction treatment. Image analysis combined with high-resolution imaging techniques is a powerful tool to objectively assess parameters like hair length, hair width, and projection area. To achieve reliable data and to reduce well known image-analysis artifacts, it was important to optimize the technical equipment for use on human skin and to improve image analysis by adaptation of the image-processing procedure to the different skin characteristics of individuals, like skin color, hair color, and skin structure. [source]


    Quantitation of cytological parameters of malignant lymphocytes using computerized image analysis

    INTERNATIONAL JOURNAL OF LABORATORY HEMATOLOGY, Issue 4 2008
    S. A. HAMID JAHANMEHR
    Summary Computerized image analysis may add to morphological evaluation by turning qualitative data into quantitative values. In this study, image analysis program was used to quantitate cytological parameters of lymphocytes in B-cell lymphoproliferative disorders. Chronic lymphocytic leukemia (CLL), mantle cell lymphoma (MCL) and B-cell prolymphocytic leukemia (B-PLL) were selected to represent typically small, medium, and large-sized lymphocytes, respectively. Image analysis was performed to determine the morphological parameters. A set of measurements was generated for quantitation of total cell area, cell diameter, cytoplasm area, nuclear area, nuclear/cell ratio, and nuclear density. The quantitated parameters substantiated morphological characteristics of the tumor cells. Comparative assessments demonstrated that CLL, MCL, and PLL can be differentiated by the quantitative descriptors. The results from image analysis may assist in defining morphological criteria and in developing quantitative cell morphology. [source]


    Pulpal status of human primary teeth with physiological root resorption

    INTERNATIONAL JOURNAL OF PAEDIATRIC DENTISTRY, Issue 1 2009
    JOANA MONTEIRO
    Objective., The overall aim of this study was to determine whether any changes occur in the pulpal structure of human primary teeth in association with physiological root resorption. Methods., The experimental material comprised 64 sound primary molars, obtained from children requiring routine dental extractions under general anaesthesia. Pulp sections were processed for indirect immunofluorescence using combinations of: (i) protein gene product 9.5 (a general neuronal marker); (ii) leucocyte common antigen CD45 (a general immune cell marker); and (iii) Ulex europaeus I lectin (a marker of vascular endothelium). Image analysis was then used to determine the percentage area of staining for each label within both the pulp horn and mid-coronal region. Following measurement of the greatest degree of root resorption in each sample, teeth were subdivided into three groups: those with physiological resorption involving less than one-third, one-third to two-thirds, and more than two-thirds of their root length. Results., Wide variation was evident between different tooth samples with some resorbed teeth showing marked changes in pulpal histology. Decreased innervation density, increased immune cell accumulation, and increased vascularity were evident in some teeth with advanced root resorption. Analysis of pooled data, however, did not reveal any significant differences in mean percentage area of staining for any of these variables according to the three root resorption subgroups (P > 0.05, analysis of variance on transformed data). Conclusions., This investigation has revealed some changes in pulpal status of human primary teeth with physiological root resorption. These were not, however, as profound as one may have anticipated. It is therefore speculated that teeth could retain the potential for sensation, healing, and repair until advanced stages of root resorption. [source]


    Immunocytochemical investigation of immune cells within human primary and permanent tooth pulp

    INTERNATIONAL JOURNAL OF PAEDIATRIC DENTISTRY, Issue 1 2006
    H. D. RODD
    Summary. Aim., The aim of this study was to determine whether there are any differences in the number and distribution of immune cells within human primary and permanent tooth pulp, both in health and disease. Design., The research took the form of a quantitative immunocytochemical study. One hundred and twenty-four mandibular first permanent molars and second primary molars were obtained from children requiring dental extractions under general anaesthesia. Following exodontia, 10-µm-thick frozen pulp sections were processed for indirect immunofluorescence. Triple-labelling regimes were employed using combinations of the following: (1) protein gene product 9·5, a general neuronal marker; (2) leucocyte common antigen (LCA); and (3) Ulex europaeus I lectin, a marker of vascular endothelium. Image analysis was then used to determine the percentage area of immunostaining for LCA. Results., Leucocytes were significantly more abundant in the pulp horn and mid-coronal region of intact and carious primary teeth, as compared to permanent teeth (P < 0·05, anova). Both dentitions demonstrated the presence of well-localized inflammatory cell infiltrates and marked aborization of pulpal nerves in areas of dense leucocyte accumulation. Conclusions., Primary and permanent tooth pulps appear to have a similar potential to mount inflammatory responses to gross caries The management of the compromised primary tooth pulp needs to be reappraised in the light of these findings. [source]


    Human monocyte response to retrieved polymethylmethacrylate particles

    JOURNAL OF BIOMEDICAL MATERIALS RESEARCH, Issue 3 2002
    Masatsugu Miyaguchi
    Abstract The purpose of this study was to compare retrieved polymethylmethacrylate (PMMA) particles from failed total hip arthroplasties in terms of size, shape, and the response of human monocytes with commercially available particles. PMMA particles were isolated from peri-implant tissues of five failed cemented total hip arthroplasties using tissue digestion and a sucrose density gradient technique. Prepolymerized cement powder and those from which barium sulfate had been removed were examined for comparison. After exposure of peripheral human monocytes to PMMA particles, tumor necrosis factor-, and interleukin-6 in medium were measured by using enzyme-linked immunosorbent assays. Image analysis revealed that retrieved particles were larger (retrieved: 1.24 ,m; prepolymerized cement powder: 0.83 ,m; barium sulfate-free powder: 0.87 ,m) and were more irregular in shape and rougher than commercially available particles. Cytokine release was increased by all PMMA particle species. However, commercially available PMMA particles stimulated the release of necrosis factor-, and interleukin-6 more strongly than did retrieved particles at very high doses. The observed difference in monocyte response might be due to the volume of the challenged particles. Another possible reason for the difference might be alteration of the surface chemistry of particles in situ and the difference in surface morphology between them. © 2002 Wiley Periodicals, Inc. J Biomed Mater Res 62: 331,337, 2002 [source]


    Prediction of Prosopis species invasion in Kenya using geographical information system techniques

    AFRICAN JOURNAL OF ECOLOGY, Issue 3 2010
    Gabriel M. Muturi
    Abstract Tree species from Prosopis genus were widely planted for rehabilitation of degraded drylands of Kenya. However, they have invaded riverine ecosystems where they cause negative socio-economic and ecological impacts. GIS was used to estimate the reverine area threatened by Prosopis invasion in Kenya. Landsat satellite images, field surveys and past studies were also used to assess the resulting potential ecological impacts in the Turkwel ecosystem in Kenya. The study revealed that 3.0 to 27.7 million hectares are threatened by invasion, based on documented riverine forests width of 0.5,3 km. Image analysis showed that 34% of the sites under positive change were invaded, with most invasions occurring in natural forests and abandoned farms. Prosopis had overall occurrence of 39% in all the sampled sites in 2007, in contrast to 0% in 1990 that was reported in an earlier study. In these areas, Acacia tortilis occurrence dropped from 81% in 1990 to 43% in 2007, suggesting that Prosopis could be displacing it. Utilization of Prosopis for fodder, fuel wood and pods for animal feeds is recommended as a management tool to reverse the trend. The methods used in this study are also recommended for invasion prediction and management in other similar ecosystems. Résumé Pour la réhabilitation de zones arides dégradées au Kenya, on a abondamment planté trois espèces de Prosopis. Cependant, elles ont envahi des écosystèmes riverains où elles ont des impacts socioéconomiques et écologiques négatifs. On a utilisé un SIG pour estimer la superficie riveraine menacée par l'invasion des Prosopis au Kenya. Des images satellite Landsat, des études sur le terrain et les résultats de travaux antérieurs ont aussi été utilisés pour évaluer les éventuels impacts écologiques dans l'écosystème de Turkwel. L'étude a révélé qu'entre 3,0 et 27,7 millions d'hectares sont menacés d'invasion, si l'on se base sur la largeur de forêt riveraine documentée, qui est de 0,5 à 3 km. L'analyse des images a montré que 34% des sites en mutation positive étaient envahis, et que la plupart des invasions touchaient des forêts naturelles et des exploitations agricoles abandonnées. Les Prosopis avaient un taux d'occurrence global de 39% dans tous les sites échantillonnés en 2007, à comparer avec le chiffre de 0% rapporté en 1990 par une étude antérieure. Dans ces zones, la présence d'Acacia tortilis a chuté de 81% en 1990 à 43% en 2007, ce qui laisse penser que Prosopis pourrait être responsable de ce déplacement. On recommande d'utiliser Prosopis comme fourrage et bois de feu et de donner les gousses au bétail, ce qui serait une façon de les gérer pour inverser la tendance. Les méthodes utilisées dans cette étude sont aussi recommandées pour prédire et gérer les invasions dans des écosystèmes comparables. [source]


    Retrospective growth analysis of Atlantic salmon Salmo salar and implications for abundance trends

    JOURNAL OF FISH BIOLOGY, Issue 10 2010
    F. Hogan
    Scale archives of Atlantic salmon Salmo salar from Maine, U.S.A., were examined to determine whether ocean conditions affected the long-term trends in S. salar populations in the southern tier of the species' range in North America. To date, scale analyses of southern tier populations have been limited to hatchery fish; previous studies suggest that post-smolt growth does not influence recruitment, with the exception that winter growth may play a role in stock maturation rate. A time series of scales from the Machias and Narraguagus Rivers spanning the years 1946 to 1999 was analysed. Image analysis was used to measure intercirculi spacing, which provided proxy variables of growth rate. Post-smolt growth increment has increased since the early 1990s, as returns have decreased, suggesting that survival factors act on post-smolts independent of growth. The data support the hypothesis of a decoupling between freshwater size and early marine growth. Growth during the second sea winter was independent of post-smolt growth, suggesting that individuals are capable of significant compensatory growth. Southern tier North American stocks exhibit a similar pattern of independence between growth and survival as observed for northern tier North American stocks. These data support the inference that the recruitment of the North American and European subspecies is governed by fundamentally different mechanisms. [source]


    Temporal Changes in Brain Volume and Cognition in a Randomized Treatment Trial of Vascular Dementia

    JOURNAL OF NEUROIMAGING, Issue 1 2001
    Joseph P. Broderick MD
    ABSTRACT Objective. To measure changes in brain and ischemic volume over time by magnetic resonance imaging (MRI) as part of a randomized treatment trial of vascular dementia. Methods. Participants who met criteria for vascular dementia underwent comprehensive neurological and neuropsychological testing on entrance, during, and at completion of the 1-year study. For those centers who had easily available MRI, MRI of the brain was to be performed on entry and completion of the study. Image analysis was performed on all balanced and T2-weighted MR films to determine ventricular, sulcal, ischemic, and hemispheric brain volumes. Results. Of the 105 patients who met the criteria for vascular dementia, 40 had a baseline MRI study that met protocol requirements and was of excellent image quality. The baseline ventricular volume in these 40 patients with high-quality MR correlated with most measures of cognitive and behavioral function, including the total Alzheimer's Disease Assessment Score (ADAS) (r= 0.51, P= .0024), as well as activities of daily living (r= 0.61, P= .0002). The baseline ischemic brain volume correlated well only with the gait and postural stability scale (r= 0.74, P= .009). Of the 40 participants, 25 had MRI studies at baseline and at completion of the study that were comparable and of excellent image quality. For these 25 patients, the mean ventricular volumes increased by 9% over the study year (P= .001) and the mean ischemic brain volume increased by 18% (P= .01). Temporal changes in the sulcal and nonischemic brain volume did not reach significance. None of the 14 clinical score measures changed significantly between baseline and completion of the study in these 25 patients. Conclusion. In summary, ventricular volume correlated well with cognitive measures in patients with vascular dementia and was a more sensitive marker for change during the study year than the clinical scales used in this study. This study also points out the practical limitations of brain imaging as a surrogate measure of clinical outcome in multicenter randomized treatment trials of brain disease. [source]


    Continuous pilot plant,scale immobilization of yeast in ,-carrageenan gel beads

    AICHE JOURNAL, Issue 7 2004
    C. Decamps
    Abstract A novel continuous two-phase dispersion process was developed to produce ,-carrageenan gel microspheres, using static mixers. It was shown that yeast-loaded carrageenan beads, with controlled diameter and tight size distribution, can be produced on a continuous basis, in a scalable mixer, at production rates appropriate to both pilot plant,scale and, potentially, industrial-scale operations. Immobilized yeast are intended to be used in continuous brewing operations. The effects of the static mixer diameter (D), the number of mixing elements (Ne), the fluid linear velocity (V), and the volumetric fraction (,) of ,-carrageenan, on the mean diameter and size distribution of the resulting gel microspheres, were studied. Image analysis showed that mean diameter was strongly influenced by the average linear fluid velocity through the mixer, and by the mixer diameter. The number of mixer elements and the mixer diameter governed bead size dispersion. A productivity of 10 L h,1 of beads was attained using a 1.27-cm-diameter static mixer. Because the productivity is proportional to the mixer diameter squared, this process, although suited for the production of small-size beads (down to 50 ,m), would be technically and economically feasible for a large industrial immobilization process. However, because the coefficient of variability increased with mixer diameter, and thus with scale-up, operational improvements are suggested, such as the use of smaller-diameter mixers operating in parallel, to reduce the size dispersion. © 2004 American Institute of Chemical Engineers AIChE J, 50: 1599,1605, 2004 [source]


    Quantification of soil structural changes induced by cereal anchorage failure: Image analysis of thin sections

    JOURNAL OF PLANT NUTRITION AND SOIL SCIENCE, Issue 3 2007
    Sacha J. Mooney
    Abstract Cereal anchorage failure, or lodging, is the permanent displacement of a crop from the vertical and results in significant annual yield losses globally. Several factors have been identified as contributors to this phenomenon but the precise mechanisms of failure are still largely unknown because of difficulties in observing these processes as they occur in situ. To identify potential soil management practices to minimize losses associated with cereal root failure, an understanding of the nature of root-soil interactions attributed to lodging is needed. An experiment was conducted that involved field impregnation and subsequent thin sectioning of lodged and unlodged root-soil complexes from contrasting soils, cereal crops, and management practices to elucidate the effects of lodging on soil structure and porous architecture. Using image analysis, size and distribution of pores in soils were quantified at both meso- (100,30 ,m) and microscales (<30 ,m). A significant effect of lodging on porosity was recorded whereby lodging reduced total porosity through compaction created by movement of the stem base, although this was variable among soil types. Pore-size distributions comprehensively supported these trends since alteration in the relative frequency of pores within specific size classes was clearly observed. The effects of lodging were more pronounced at the mesoscale because the data were more susceptible to variations created by natural soil heterogeneity at the microscale. These data suggested that sideways movement of the subterranean stem within the soil is a significant factor which is likely to affect the propensity for a cereal plant to lodge, indicating soil strength in the upper part of the soil profile is crucial. [source]


    RHEOLOGY AND MICROSTRUCTURE OF WHEAT DOUGH DEVELOPED WITH CONTROLLED DEFORMATION

    JOURNAL OF TEXTURE STUDIES, Issue 1 2000
    EMILY J. SCHLUENTZ
    ABSTRACT Undeveloped wheat dough samples were strained in shear and extensional flow between parallel plates to produce a controlled level of development. Dough made in a standard Farinograph, considered developed dough, was used for comparison. Scanning electron microscopy images of deformed dough were subjected to numerical image processing to characterize the protein matrix present. Results were compared to dynamic rheological properties to evaluate the influence of strain deformation on the formation of microstructure. Viscoelastic moduli of wheat dough showed that developed dough had the greatest amount of structure formation, followed by extensionally-strained and shear-strained samples, respectively. Undeveloped dough showed the lowest levels of structure development. Image analysis indicated statistically significant differences between protein matrices in developed and undeveloped samples; however, results were not significantly different between shear- and extension-ally-strained samples. [source]


    Coarsening of Lamellar Microstructures in Directionally Solidified Yttrium Aluminate/Alumina Eutectic Fiber

    JOURNAL OF THE AMERICAN CERAMIC SOCIETY, Issue 12 2001
    Deok-Yong Park
    Coarsening of the fine lamellar structure of a directionally solidified Y3Al5O12 (yttrium aluminum garnet, YAG)/Al2O3 eutectic fiber at elevated temperatures was investigated. The fibers were grown continuously by an edge-defined film-fed growth (EFG) technique. To study the thermal stability of the lamellar structure, the fibers were heat-treated in air at 1360°,1460°C for up to 200 h. X-ray diffractometry and scanning electron microscopy were used to characterize the microstructures of the fibers. Image analysis was used to measure the length of the interface line between Y3Al5O12 and Al2O3 phases. The kinetics of coarsening and the rate-controlling mechanisms were investigated. Also, the Graham and Kraft model for describing the coarsening behavior of the lamellar Al-CuAl2 eutectic alloy was used to explain the coarsening behavior of Y3Al5O12/Al2O3 eutectic fiber. [source]


    Influence of heating conditions and starch on the storage modulus of Russet Burbank and Yukon Gold potatoes

    JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 15 2001
    Renan Bu-Contreras
    Abstract The storage modulus of Russet Burbank (RB) and Yukon Gold (YG) potato discs (13.3,mm,× 4.5,mm) was measured continuously during heating in water at temperatures ranging from 40 to 80,°C for 120,min using a dynamic mechanical analyser with a heating stage. The starch content of YG potatoes was higher than that of RB potatoes, but the raw starch granule size distribution of both varieties was similar. RB samples had the highest storage modulus values (25% higher than raw tissue) when heated in 60,°C water for 35,min. Image analysis revealed that the perimeters of starch granules in the potato samples increased by about 50% during heating for 30,min at 60,°C. Heating temperature and time and starch content influenced the storage modulus. © 2001 Society of Chemical Industry [source]


    Assessment of hepatic steatosis: comparison of quantitative and semiquantitative methods in 108 liver biopsies

    LIVER INTERNATIONAL, Issue 4 2009
    Bruno Turlin
    Abstract Background: There is growing interest in the role of hepatic steatosis in liver injury. The current standard for steatosis assessment is histological grading, although there is variability in the scoring systems used. Aims: The aim of this study was to compare steatosis assessment by image analysis and histological grading. Methods: Three methods were used to measure steatosis: histological grading (from 0 to 4); estimation of the percentage of hepatocytes (to nearest 5%) with steatosis; and computer-assisted image analysis. Image analysis was performed on multiple fields for each biopsy with image pro plus 4.5, with steatotic droplets identified on the basis of shape, colour and size. Computer-selected objects were reviewed to ensure that these were steatotic droplets. The predictive accuracy of the three techniques was assessed using measures of obesity and insulin resistance (homeostasis model assessment) as the outcome variables. Results: There was a strong correlation between the results of image analysis and histological grade (rs=0.89, P<0.01), and estimated per cent steatosis (rs=0.93, P<0.01). The variability in the area of steatosis calculated by image analysis in different fields of a biopsy correlated with the total steatosis area (rs=0.93, P<0.01). Conclusions: Image analysis did not offer any additional predictive value when the association between degree of obesity or insulin resistance was correlated with the different methods of assessing steatosis. Image analysis allows measurement of area of steatosis in liver biopsy material and generates a continuous variable that facilitates statistical analysis. These aspects may prove beneficial in research settings. [source]


    Overexpressed growth hormone (GH) synergistically promotes carcinogen-initiated liver tumour growth by promoting cellular proliferation in emerging hepatocellular neoplasms in female and male GH-transgenic mice

    LIVER INTERNATIONAL, Issue 2 2001
    Kenneth J. Snibson
    Abstract:Background/Aims: Growth hormone (GH), when overexpressed in male and female GH-transgenic mice, is known to induce liver tumours within 1 year. This study aimed to gain a clearer understanding of the interaction between GH and tumour cells in vivo. Methods/Results: The carcinogen diethylnitrosomine (DEN) was administered to neo-natal transgenic and non-transgenic mice maintained in a "hepatocarcinogenesis resistant" genetic background (C57BL/6J). Macroscopic, microscopic and liver weight/body weight ratio analyses revealed that carcinogen-induced hepatocarcinogenesis was dramatically accelerated in young GH-transgenic mice compared to non-transgenic counterparts. Image analysis of microscopic hepatocellular neoplasms showed rapidly increasing tumour burdens, and neoplastic foci size over time in young adult GH-transgenic mice. The magnitude of enhanced tumour growth was equivalent in both male and female transgenic mice, whereas much lower and sexually dimorphic tumour growth rates (males>females) were observed in non-transgenic mice treated with DEN. BrdU labelling experiments demonstrated that rapid tumour growth in carcinogen-treated GH-transgenic mice was due to the promotion of cell proliferation in emerging lesions. Tumour cell proliferation in young GH-transgenic mice was 2.6- and 4-fold higher, respectively, than that observed in similar age male and female non-transgenic mice. Interestingly, both GH-transgenic and non-transgenic mice displayed progressively slower tumour growth rates in older animals. Conclusion: Overall, GH synergistically promotes carcinogen-induced hepatocarcinogenesis in both sexes of GH-transgenic mice by stimulating tumour cell proliferation. [source]


    Image analysis and morphometry in the diagnosis of breast cancer

    MICROSCOPY RESEARCH AND TECHNIQUE, Issue 2 2002
    Joan Gil
    Abstract Image Analysis, a complicated field still in the early stages of application to Pathology, has the capability of rendering major contributions to the diagnosis, prognosis, and management of malignancies of the breast. The present review summarizes the main problems and the general approach to the use of this technique for quantitating immunohistochemical stain results, obtaining DNA histograms, and making de novo diagnoses in routine materials of the Pathology service. In the case of diagnosis, the main steps are sampling, segmentation, and measures of chromatin texture. Currently, the limiting factor for all routine applications of image analysis is probably the absence of a reliable automatic nuclear segmentation. Microsc. Res. Tech. 59:109,118, 2002. © 2002 Wiley-Liss, Inc. [source]


    Improvement of peripheral nerve regeneration in acellular nerve grafts with local release of nerve growth factor

    MICROSURGERY, Issue 4 2009
    Hailong Yu M.D.
    Previous studies have demonstrated the potential of growth factors in peripheral nerve regeneration. A method was developed for sustained delivery of nerve growth factor (NGF) for nerve repair with acellular nerve grafts to augment peripheral nerve regeneration. NGF-containing polymeric microspheres were fixed with fibrin glue around chemically extracted acellular nerve grafts for prolonged, site-specific delivery of NGF. A total of 52 Wister rats were randomly divided into four groups for treatment: autografting, NGF-treated acellular grafting, acellular grafting alone, and acellular grafting with fibrin glue. The model of a 10-mm sciatic nerve with a 10-mm gap was used to assess nerve regeneration. At the 2nd week after nerve repair, the length of axonal regeneration was longer with NGF-treated acellular grafting than acellular grafting alone and acellular grafting with fibrin glue, but shorter than autografting (P < 0.05). Sixteen weeks after nerve repair, nerve regeneration was assessed functionally and histomorphometrically. The percentage tension of the triceps surae muscles in the autograft group was 85.33 ± 5.59%, significantly higher than that of NGF-treated group, acellular graft group and fibrin-glue group, at 69.79 ± 5.31%, 64.46 ± 8.48%, and 63.35 ± 6.40%, respectively (P < 0.05). The ratio of conserved muscle-mass was greater in the NGF-treated group (53.73 ± 4.56%) than in the acellular graft (46.37 ± 5.68%) and fibrin glue groups (45.78 ± 7.14%) but lower than in the autograft group (62.54 ± 8.25%) (P < 0.05). Image analysis on histological observation revealed axonal diameter, axon number, and myelin thickness better with NGF-treated acellular grafting than with acellular grafting alone and acellular grafting with fibrin glue (P < 0.05). There were no significant differences between NGF-treated acellular grafting and autografting. This method of sustained site-specific delivery of NGF can enhance peripheral nerve regeneration across short nerve gaps repaired with acellular nerve grafts. © 2009 Wiley-Liss, Inc. Microsurgery, 2009. [source]