Controlled nanostructrures formation by ultra fast laser pulses for color marking.

Precise nanostructuration of surface and the subsequent upgrades in material properties is a strong outcome of ultra fast laser irradiations. Material characteristics can be designed on mesoscopic scales, carrying new optical properties. We demonstrate in this work, the possibility of achieving material modifications using ultra short pulses, via polarization dependent structures generation, that can generate specific color patterns. These oriented nanostructures created on the metal surface, called ripples, are typically smaller than the laser wavelength and in the range of visible spectrum. In this way, a complex colorization process of the material, involving imprinting, calibration and reading, has been performed to associate a priori defined colors. This new method based on the control of the laser-driven nanostructure orientation allows cumulating high quantity of information in a minimal surface, proposing new applications for laser marking and new types of identifying codes.

Three-dimensional modeling system for unilateral mandibular bone distraction: a clinical case.

Facial hemiatrophies are anomalies of the first branchial arch and affect one in 4000-5000 newborns. Bone distraction is the technique of choice for the treatment of these dysmorphoses. Mandibular osteodistraction requires prior determination of the characteristics of the distraction vector whose three components will serve to activate the distractor. The patient, aged 5 years, presented with a right facial hemiatrophy, Grade IB according to the classification of Pruzansky. Tomodensitometric acquisition was obtained with a CT scanner. Software specifically designed for this application allows segmentation of the anatomical elements by a region-growing algorithm. The 3D representation of each element is added to a 3D scene, in which are placed the built-up landmarks necessary for the surgical simulation after 3D cephalometric analysis. The surgical cleavage plane is oriented according to the surgeon's requirements while preserving the predominant anatomical elements. The software allows performance of rotations and translations of the bone segments rendered independently from the cleavage plane. The distances and angles covered during the virtual movement are measured at its conclusion. The aim of moving the bone segments is to render the mandibular occlusion plane parallel to the reference occlusion plane. The vertical growth of the maxilla is realized by secondary recuperation. The distractor used was of an external multidirectional type allowing elongation of the mandibular ramus and mandibular corpus, closure of the goniac angle, and lateralization or medialization of the ramus. On the 15th day, the mandibular angle was reduced by 10 degrees, which allowed closure of the anterior gap and recentering of the incisive areas by a half-cuspid. The patient presented with a complex bone deficit in the three spatial directions, which allowed the development of software for modeling the distraction. Other clinical cases will be necessary to validate this 3D imaging-based technique.

Peritoneal infection: a possible redox disease.

In a recent report, pertaining to Bacteroidesfragilis peritonitis, the influence of oxidation-reduction (redox) potential provided experimental evidence for B. fragilis penetration into Hela cell monolayers (using 3D imaging techniques). Bacteria grown under oxidizing conditions (+mV redox) penetrated into tissue cells unlike that of reducing conditions (-mV redox). The present results emphasise the significance of the level of redox potential during infection with an interpretation based on anaerobe/aerobe environmental flux, triggering the invasive mechanism.

An investigation of segmentation methods and texture analysis applied to tomographic images of human vertebral cancellous bone.

The goal of this study is to determine architectural and textural parameters on computed tomographic (CT) images, allowing us to explain the mechanical compressive properties of bone. Although the resolution (150 microm) is of the same order of magnitude as the trabecular thickness, this method enables the possibility of perfecting an in vivo peripheral CT system with an acceptable radiation dose for the patient. This study was performed on L2 vertebrae cancellous bone specimens taken after necropsy in 22 subjects aged 47-95 years (mean: 79 years). The segmentation process is a crucial point in the determination of accurate architectural parameters. In this paper the use of two different segmentation methods is investigated, based on an edge enhancement and a region growing approach. The images are compared and the architectural parameters extracted from the images segmented by both methods lead to a quantitative evaluation. The parameters are found to be globally robust towards the segmentation process, although some of them are much more sensitive to the approach used. Highly significant correlations (P < 0.0005) have been obtained between the two segmentation methods for all the parameters, with rho ranging from 0.70 to 0.93. In order to improve the assessment of bone architecture, texture analysis (run length method) was investigated. New features are obtained from an image reduced to 16 grey-levels. Textural parameters in addition to architectural parameters in a multivariate regression model increase significantly (P = 0.01) the prediction of the maximum compressive strength (variation of r2 from 0.75 up to 0.89).

Marsupialization of dentigerous cyst associated with foreign body using 3D CT images: a case report.

This paper documents a marsupialized dentigerous cyst associated with an amalgam. The surgical challenge was removing the amalgam from the cystic lining with zero visibility. To achieve this, the surgical procedure was computer assisted and used 3D images. Distances between the amalgam and various anatomical landmarks were assessed in order to define a path from the top of the ridge to the amalgam. The path was reconstructed at the surgical site and the amalgam removed by suction. Orthodontic treatment was associated with surgery. Three dimensional imaging is a useful procedure for deciding on the type of surgical technique likely to minimize trauma. This report is also a contribution to the literature by reporting two dentigerous cysts associated with amalgam.

Criteria for the assessment of intrinsic performances of digital radiographic intraoral sensors.

RATIONALE AND OBJECTIVES: In sensor-based dental digital radiographic imaging systems, it should be possible to assess the intrinsic performance of the sensor by means of objective criteria, independent of the related electronic hardware and image-treatment software. METHODS: Six criteria are presented and discussed for the objective assessment and quantification of the intrinsic performance of intraoral sensors for dental digital radiography, independent of the characteristics of the subsequent image-treatment software. The criteria are signal-to-noise ratio, blooming, sensitivity, spatial uniformity, modulation transfer function, and geometric deformations. These criteria have been used to evaluate the Visualix sensor. RESULTS: For each criterion, a series of numerical data are presented as graphs. CONCLUSION: A method is proposed for objective assessment of radiographic sensors that makes it possible to compare sensors with each other and with conventional radiographs. The criteria proposed also increase understanding of digital diagnostic images and improve their clinical use.

LIP-model-based three-dimensional reconstruction and visualization of HIV-infected entire cells.

This paper presents a global solution from acquisition to visualization for the three-dimensional reconstruction of cell sections. Original techniques are proposed for the correct handling of geometrical section distortions, and a new interpretation based on the logarithmic image processing (LIP) model is applied in order to create normalized grey-level sections where these are missing. Finally, a new method for generating a mesh of triangles to describe the envelope of the reconstructed cell is proposed, as well as a visualization mixing image synthesis and grey-level information. The product allows the user to explore the reconstructed cellular block in any desired direction, by showing user-defined grey-level sections inside the block mixed to a synthetic view of the cell envelope.

Three-dimensional electron microscopy of entire cells.

The digital processing of serial electron-microscope sections containing laser-induced topographical references allows a three-dimensional (3-D) reconstruction of entire cells at a depth resolution of 40-60 nm by the use of novel image analysis methods. The images are directly processed by a video-camera placed under the electron microscope in TEM mode or by the electron counting device in STEM mode. The deformations associated with the cutting of embedded cells are back-calculated by new computer algorithms developed for image analysis and treatment. They correct the artefacts caused by serial sectioning and automatically reconstruct the third dimension of the cells. Used in such a way, our data provide definitive information on the 3-D architecture of cells. This computer-assisted 3-D analysis represents a new tool for the documentation and analysis of cell ultrastructure and for morphometric studies. Furthermore, it is now possible for the observer to view the contents of the reconstructed tissue volume in a variety of different ways using computer-aided display techniques.

Contrast definition and contour detection for logarithmic images.

Logarithmic images, such as images obtained by transmitted light or those produced by the human visual system, differ from linear images. Their processing and analysis require consequently specific laws and structures. The latter have been developed in the concept of a logarithmic image processing (LIP) model (Jourlin & Pinoli, 1987, 1988; Pinoli, 1987a). This model permits the introduction of a well-justified contrast definition: from a physical point of view, it is closely linked with logarithmic images and from a mathematical point of view, it is set up in an algebraic structure. The applications presented at the end of this paper concern image preprocessing and segmentation. In particular, in the case of microscopic images, the proposed method of segmentation gives good results with transmitted light (thin foils in biology or transmitted electronic microscopy). However, images obtained by reflected light microscopy are not within the scope of this model.

[Self-medication in rheumatologic consultation. Apropos of a study on 895 patients]. / L'automédication en consultation rhumatologique. A propos d'une étude portant sur 895 malades.

A study was undertaken to evaluate the use of self-administered medication in 895 patients with rheumatologic disorders by all of the 18 rheumatologists practicing in one region (the southern portion of the Loire Department and all of the Haute-Loire Department) over a six-day period. It was noted that 445 out of 895 patients (49.72 percent) reported taking one or several medications other than those prescribed during the previous 3 month period before their office visit. Self-administered medications were taken at least weekly in 53.5 percent of cases and at least monthly in 83,7 percent. Most often one or two medications were involved (60.9 and 25.6 percent respectively). Age, profession, the presence or absence of psychiatric disturbances, the duration of the doctor-patient relationship, as well as the patient's specific rheumatologic problem seemed to be influencing factors. Aspirin or other analgesics comprised 53.1 percent of the medication taken, whereas other non-steroidal antiinflammatory agents comprised only 2.3 percent. No steroids were self-administered. There are multiple potential side effects with self-administered drugs: therapy can be poorly suited for the illness in question, it may delay diagnosis and the beginning of effective therapy, there can be increased iatrogenic risk due to inadequate therapy, and unnecessary expense. Drugs used as self-administered medications originate most often from previous medical prescriptions which may or may not have been prescribed for the patient's same medical problem (34.4 percent), and most medication used was bought without needing a prescription (52.4 percent). Prevention, therefore, requires that potential consumers of self-administered drugs be educated concerning these problems, as well as health professionals, the pharmaceutical industry, and concerned government agencies.

In vitro decondensation of the human spermatozoan nucleus and image analysis. Quantitative data on the kinetics of in vitro decondensation of the human spermatozoan nucleus.

The authors subjected 14 human sperm samples to decondensation in vitro. They analyzed the images of a total of 9,681 objects as a function of time of decondensation. The discussion bears on the heterogeneity of the process of chromatin decondensation in human spermatozoa, on the influence of the zinc/fructose ratio in the seminal fluid and on the role of the period during which the spermatozoa are left in contact with the fluid.

Automated cytopathologic diagnosis of bronchial carcinoma. II. Preliminary results of classifying cytocentrifuged bronchial brushings.

An automated discrimination between healthy and neoplastic bronchial cells was performed on eight bronchial smears prepared by cytocentrifugation. An image analyzer was used to examine 415 cells in these smears. The nuclear surface of each cell was measured, as was the total integrated optical density for 25 programmed thresholds. The results show that it is possible to distinguish healthy from cancerous cells in a given subject using these two measured parameters and two new parameters deduced mathematically. It appears difficult, however, to demonstrate a typical healthy and typical cancerous bronchial cell that could be used as a reference for all subjects. It is thus the presence of cell heterogeneity in a given subject that enables him or her to be characterized as healthy or having cancer.

[In vitro decondensation of the human spermatozoan nucleus and image analysis]. / Décondensation in vitro du noyau du spermatozoïde humain et analyse d'image.

Between the first stage: differentiation of the human spermatozoa from spermatid in testicle, and the second one: formation of male pronucleus in ovum, the nucleus of spermatozoa undergoes a chromatin condensation and a chromatin decondensation mechanism. Besides it is possible to get this decondensation mechanism in vitro by putting spermatozoa into specific solution with the purpose of carry out an image analysis. The aim of this study was to manage a quantitative analysis of the in vitro nuclear chromatin decondensation of human spermatozoa with an image analyzer of T.A.S. "texture analysis system".