André Assimacopoulos’s research while affiliated with University of Geneva and other places

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Publications (9)


Auditory browser for blind and visually impaired users
  • Conference Paper

January 1999

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8 Reads

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16 Citations

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Lori Petrucci

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Thierry Pun

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André Assimacopoulos


Figure 1: Examples of HTML documents used for testing.
Figure 2: Tactile Braille gradations surrounding the screen.
Figure 3a: Bloc subdivision of the image. Figure 3b: Display of the local attribute computed over each bloc.
AB – Web : Active audio browser for visually impaired and blind users
  • Conference Paper
  • Full-text available

November 1998

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9 Reads

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11 Citations

Download

An Image-Capable Audio Internet Browser for Facilitating Blind User Access to Digital Libraries.

January 1998

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2 Reads

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4 Citations

The Internet now permits widespread access to textual and pictorial material from digital libraries. The widespread use of graphical user interfaces, however, increasingly bars visu- ally handicapped people from using such material. We present here our current work aimed at the adaptation of an Internet browser to facilitate blind user access to digital libraries. The main distinguishing characteristics of this browser are: (1) active user interaction, both for the macro- analysis and micro-analysis of screen objects of interest; (2) use of a touch-sensitive screen to facilitate user interaction; (3) generation of a virtual sound space into which the screen information is mapped; (4) transcription into sounds not only of text, but also of images. Several prototypes have been implemented, and are being evaluated by blind users.


Distribution and function of cytoskeletal proteins in lung cells with particular reference to 'contractile interstitial cells'

February 1979

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13 Reads

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39 Citations

Methods and Achievements in Experimental Pathology

Cytoskeletal proteins are demonstrated in the interstitial cells of the lungs. These proteins appear in the cytoplasm as bundles of microfilaments, the individual filaments measuring 40--80 A in diameter. The presence of actin and myosin in these cells is demonstrated by immunofluorescence. Antiactin antibodies (AAA) obtained from patients with chronic aggressive hepatitis, as well as AAA and antimyosin antibodies prepared in the rabbit, are used. The major difference between the cytoskeletal proteins of interstitial cells and other cells of the alveolar tissue (type II epithelium, pericytes, and near the junctional complexes of endothelial cells) is that the microfilaments within the interstitial cells are organized into bundles forming tiny intracytoplasmic 'muscles'. Furthermore, they appear to be much more abundant and seem to anchor the cell on the alveolar basement membrane by hemidesmosome-like structures. These peculiar cytological features provide these cells with an important functional capacity. Being located in the 'pillars' which cross the capillary space, the contraction of interstitial cells may modify the alveolocapillary configuration in some circumstances. The physiological importance of such an 'active' alveolar motility is to provide the lung with a mechanism of autoregulation of the ventilation/perfusion (V/Q) ratio at alveolar level.


Changes in alveolar capillary configuration at different levels of lung inflation in the rat. An ultrastructural and morphometric study

February 1976

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7 Reads

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34 Citations

Laboratory Investigation

Changes in alveolar capillary configuration during positive pressure lung inflation were investigated by transmission and scanning electron microscopy as well as by morphometric methods. As the airway pressure was raised, an increasing number of alveoli expanded. However, in fully inflated or overinflated lungs, a few collapsed areas persisted. In such areas, the air-blood tissue barrier was folded into the capillary space, dividing it into intercommunicating chambers. In expanded alveoli, the capillaries appeared as a continuous space delimited at each side by a tissue leaflet. This space was crossed by tissue bridges consisting of the thick portion of air-blood barrier. In overinflated lungs, the capillary space was compressed between the alveoli and thus collapsed. Our findings suggest that the thin porne. The variations of the capillary configuration seem to be determined either by "passive" deformations or by compression of the alveolocapillary membrane, or as a result of contraction of interstitial cells which are located in the thick portion of the air-blood barrier and are attached to the basement membranes of two adjacent alveoli. The relationship between alveolar dynamics and capillary configuration is considered to be a basic factor in ventilation/perfusion auto-regulation.


Lung fixation by perfusion—A simple method to control the pressure in the perfusion circuit

April 1974

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5 Reads

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6 Citations

Journal of Microscopy

SUMMARYA simple method which maintains the hydraulic pressure at a constant level during fixation of organs by perfusion is described. This is obtained by means of a glass tube interposed between a peristaltic pump and the organ to be perfused, the specially designed glass tube acting as a safety valve. The efficiency of the system is tested by electromagnetic pressure recording.


'Contractile interstitial cells' in pulmonary alveolar septa: a possible regulator of ventilation/perfusion ratio? Ultrastructural, immunofluorescence, and in vitro studies

March 1974

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79 Reads

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325 Citations

Yusuf Kapanci

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André Assimacopoulos

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[...]

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In the lungs of healthy rats, humans, lambs, and monkeys, about 50% of the alveolar interstitial cells-resembling fibroblasts-contain bundles of fibrils measuring 30-80 A in diameter. Immunofluorescence studies on frozen sections of rat lung demonstrate that many interstitial cells bind sera containing antiactin antibodies. On account of these two sets of findings and our additional in vitro studies suggesting alveolar tissue contraction due to hypoxia or epinephrine, we postulate that the alveolar septa contain contractile cells different from that of smooth muscle. For these cells we propose the name of "contractile interstitial cells." Such cells lie within the thick portion of the air-blood barrier and around the pre- or postcapillary vessels. Hence it is possible that they play a role in the autoregulation of ventilation/perfusion (V/Q) ratio, particularly in hypoxic pulmonary hypertension. These findings, demonstrating a contractile system other than bronchial and arterial smooth muscle, suggest that the alveolus should no more be conceived as a passive "organ."


Citations (8)


... If an audio document is designed straight from the author's intentions, it may correspond to the author making an explicit recording the user study presenting voice based html structure in audio: user satisfaction with audio hypertext of the document or pieces of the document. Patrick Roth [19] and his group project aims at providing sight handicapped people with alternative access modalities to pictorial documents. More precisely, our goal is to develop an augmented Internet browser to facilitate blind users access to the World Wide Web. ...

Reference:

Development of an Agent Based Specialized Multi-Lingual Web Browser for Visually Handicapped
AB – Web : Active audio browser for visually impaired and blind users

... Methods include computer vision, ultrasonic sensors, tactile substitution via skin receptors, auditory substitution via the ears, vibro-tactile substitution, electrical stimulations (e.g. of the visual cortex [31], of the forehead [57], of the tongue [3]), medical or surgical approaches, etc. Applications include wearable assistive devices, mobility aids and electronic travel aids, visual prosthetic devices, brain implants, bionic eyes; for e.g. computer vision-based cortical implants for bionic vision [70,71] and retinal implants, etc. 2. Accessible Content Processing (Purple)-A community which attempts to cover urgent areas such as human computer interaction (HCI), Braille-related technologies, printed information access (such as textbooks, street signs, product information, bar codes), optical character recognition (OCR) technology, speech synthesis technology, sign detection and recognition, web accessibility, etc; Methods include tactile access, sonification of data (e.g. use of nonspeech sound for accessing georeferenced data [115]), audio transcriptions of printed information, audio browsers to access web sites and web content [93]; Applications include reading devices, smartphone apps (e.g. the Trinetra project [65], or the bar code reading app for the blind from the Smith-Kettlewell Eye Research Institute [108]), low vision aids, screen readers, tactile touchscreens and tactile maps. 3. Accessible User Interface Design (Blue)-We interpret this small community in the co-occurrence graph as an active community involved in areas such as human-computer interaction (HCI), interface design, user interface modelling, Braille technology, ubiquitous computing, human factors and ergonomics research, etc; Methods include user-centered design, auditory interactions and feedbacks, multiple accessibility features, design and usability evaluations; Applications include accessible user interface designs, frameworks for dual interfaces, non-visual interfaces to ubiquitous services (such as ATM machines, kiosks, home appliances), accessible games for the visually impaired [39], etc. ...

Auditory browser for blind and visually impaired users
  • Citing Conference Paper
  • January 1999

... Furthermore, because many digital libraries rely on pointers to documents on the Web, it is important that these mechanisms work on Web pages. While these limitations have been recognized for over a decade [1, 3], assistive technology is still challenged by two-dimensional Web page layout designs. For the past 2 years, we have worked on devising better assistive technologies to allow blind people to access the information implicit in document layouts, and to provide them with a user experience closer to that of sighted people. ...

An Image-Capable Audio Internet Browser for Facilitating Blind User Access to Digital Libraries.
  • Citing Conference Paper
  • January 1998

... The studies of Lumbreras and al. [6] and our earlier work [8,9] validated the hypothesis that a 3D immersive virtual sound environment combined with haptic manipulation and audio feedback, can enable blind users to construct a mental representation of the spatial environment. Therefore, we use as the haptic device, a graphical tablet that provides a direct positioning of the finger in the auditory plane. ...

An audio browser for increasing access to world wide web sites for blind and visually impaired computer users.
  • Citing Conference Paper
  • January 1999

... The pulmonary vasculature is essential for alveoli formation, which is disrupted when angiogenesis is inhibited [19][20][21][22][23]. Equally important are the alveolar myofibroblasts, believed to direct alveolar septal formation by controlling elastin synthesis [24,25]. During alveologenesis, plateletderived growth factor receptor alpha (PDGFRα) expressing myofibroblast progenitors differentiate into alpha smooth muscle actin (α-SMA) alveolar myofibroblasts which are anchored onto the basement membrane [26][27][28][29]. Mice with defective myofibroblast differentiation and proliferation reveal phenotypes of impaired alveolar development [30][31][32]. ...

Distribution and function of cytoskeletal proteins in lung cells with particular reference to 'contractile interstitial cells'
  • Citing Article
  • February 1979

Methods and Achievements in Experimental Pathology

... While bulk scattering provides the contrast mechanism within the tissue, it also distorts the focal spot and degrades the resolution. These factors limit our ability to trace the exact boundary of the alveolar air spaces, as there may be miniature folds within the septa that are smaller than the resolution of the system, as seen with electron microscopy [35,[42][43][44][45]. Additional studies are required to determine the primary mechanism for the reconstruction error and formulate correction techniques to provide more exact measurements of alveolar volume and surface area. ...

Changes in alveolar capillary configuration at different levels of lung inflation in the rat. An ultrastructural and morphometric study
  • Citing Article
  • February 1976

Laboratory Investigation

... Also, there are many studies on the stimulation of the testicular capsule by various agents: electrical excitation and norepinephrine [39,40], F1 prostaglandins [41], hypoxia or anoxia, and epinephrine [42]. The different intervals between stimulation and maximum response could be due to the number of myofibroblasts, differentiation of cytoplasmic filaments, and other plasma membrane receptors [40]. ...

'Contractile interstitial cells' in pulmonary alveolar septa: a possible regulator of ventilation/perfusion ratio? Ultrastructural, immunofluorescence, and in vitro studies

... .) Nembutal (17 mg/100 g) were fixed by perfusion (10)(11)(12) ; 6 other rat lungs were fixed by conventional intratracheal instillation. We used 2% glutaraldehyde adjusted with phosphate buffer and saccharose to pH 7 .4 ...

Lung fixation by perfusion—A simple method to control the pressure in the perfusion circuit
  • Citing Article
  • April 1974

Journal of Microscopy