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[Examination of the patient with supraglottic carcinoma at the medical office. Contribution of the rigid optical devices and the fiberscope].

Seventy one patients afflicted of supraglottic carcinoma were included in a prospective study whose purpose was to determine which of three optical tools available at the medical office--indirect mirror laryngoscopy, laryngotelescopy and fiberscopic examination--is the most suitable to examine the larynx of patients with this disease. No significant differences were found among these explorations in the easily observable regions, as the hypopharyngeal areas and the epilarynx. The examination of the pericommisural region--the most difficult area to see--was easier with the flexible fiberscope. The laryngotelescope provided better visualization than the mirror laryngoscopy. Exploration with the new optical devices did not correct the errors in the interpretation of images made with the mirror laryngoscopy. We conclude that flexible fiberoptic laryngoscopy provides better information than other diagnostic tools for the assessment of patients with supraglottic carcinoma at the medical office.

Carcinoma, Squamous Cell↗
PubMed2004

Evaluation of a fibre optic device in solution equilibria studies. Application to 3-hydroxybenzoic acid ionization.

The use of a fibre optic device for spectrophotometric measurements in solution equilibria studies is presented. In particular the precision obtainable with such equipment is evaluated as a function of different experimental conditions, such as path length, averaging time and stirring of the solution. Analysis of 3-hydroxybenzoic acid ionization is presented to assess the results obtained in the study of an equilibrium system.

Fiber Optic Technology↗
PubMed2006

Treatment of cellulite with optical devices: an overview with practical considerations.

Cellulite is a common condition in women for which treatment is frequently requested. Its etiology is unknown, but a myriad of factors including genetics, hormones, and inflammation appear to contribute to its formation. Despite the popularity of therapies touting their effectiveness for this pervasive condition, few have proven long-lasting benefits. Lasers and light sources are the latest devices to have entered the cellulite therapeutic market. This paper describes these optical devices and provides an overview of their published effectiveness.

Adipose Tissue↗
PubMed2003

On-line monitoring of biofilm formation in a brewery water pipeline system with a fibre optical device.

Any advanced anti-fouling strategy must be based on early warning systems which allow for timely, precisely directed and optimized countermeasures. Such systems must be able to detect biofilm growth on representative surfaces. In order to meet this requirement, a fibre optical device (FOS) has been developed. It is based on light which is scattered by objects deposited on the tip of an optical fibre. A receiving fibre collects the signal and forwards it to a detection and quantification unit. Both the sending and the receiving fibre are mounted in a measuring head which is integrated evenly on the inner surface of a water pipeline at representative sites. This device was applied to a water system of a brewery in order toput its reliability to test under practical conditions. The FOS detected the build-up of a deposit which was identified independently as consisting of microorganisms, i.e., a biofilm. A stable, well detectable and reproducible signal could be obtained above a colonization of 10(5) cells cm-2. Adjustment of the sensitivity of the amplifier allowed for detection of biofilms up to 10(10) cells cm-2. Cleaning countermeasures could be detected clearly by a decrease of backscattered light intensity. The system proved to be suitable for on-line, non-destructive, real-time and automatic monitoring for a period of almost two years, and thus, provides an important constituent for an advanced anti-fouling strategy.

Automation↗
PubMed2000

Measurement of subcutaneous adipose tissue topography (SAT-Top) by means of a new optical device, LIPOMETER, and the evaluation of standard factor coefficients in healthy subjects.

The quantification of obesity in respect to subcutaneous adipose tissue and fat distribution is a matter of interest. We recently reported on a new optical device, LIPOMETER, and its ability to measure the thickness of subcutaneous adipose tissue and its advantages compared with other methods. To describe the subcutaneous adipose tissue distribution of the human body in a precise, reproducible, and comparable manner, 15 well-defined body sites distributed from neck to calf on the right body side were used. This set of sites defines subcutaneous adipose tissue topography (SAT-Top). To visualize SAT-Top for subjects or groups, special SAT-Top plots were used. Subcutaneous adipose tissue distribution can be recognized easily with these techniques. SAT-Top of 590 healthy men and women was measured. Factor analysis was used to extract the essential information from these 590*15 intercorrelated single measurements and to provide standard factor coefficients for later applications. As an example of how to use the results of factor analysis, the strong SAT-Top deviation of women with clinically proven type-2 diabetes mellitus (NIDDM) from healthy controls is described. Am. J. Hum. Biol. 12:231-239, 2000. Copyright 2000 Wiley-Liss, Inc.

Journal Article↗
PubMed2002

A fast Green's function method for the analysis of IDT's for acousto-optical devices.

Surface acoustic wave (SAW) interdigital transducers are key components in X-Y LiNbO3 acousto-optical (A-O) devices. SAW interdigital transducers (IDT's) on this substrate exhibit a high spurious resonance that may reduce the A-O efficiency. In this paper we present a detailed analysis of X-Y LiNbO3 IDT's based on a fast Green's function method (GFM). In order to correctly evaluate the spurious effects on IDT's performance, we also considered bulk terms of the Green's function. When the GFM is applied to IDT's with general topology and over a wide frequency range, the required computation time can reach quickly unacceptable values for long IDT structures. We developed a new model order reduction technique based on the singular value decomposition (SVD) for the fast generation of the IDT's frequency response. Numerical results for different configurations of X-Y LiNbO3 IDT's are in good agreement with measured data and a correct interpretation of the spurious resonance is reported. It is pointed out that bulk wave excitation may be a serious limitation in the design of efficient, wide band IDT's for A-O devices.

Acoustics↗
PubMed1993

An optical device to measure the dynamics of apex rotation of the left ventricle.

Systolic counterclockwise rotation of the left ventricular apex with respect to the base has been defined as left ventricular (LV) twist or torsion. If rotation of the base during systole is small, we hypothesized that the dynamics of twist can be well characterized through the measurement of apical rotation alone. A device was designed to measure apical rotation in a simpler, more direct fashion, providing continuous high-fidelity dynamic measurements. The device consists of a light source, a position-sensitive diode, and a small rotating mirror that is coupled to the apex of the heart by a wire. As the wire rotates, apical rotation (measured in degrees) can be calculated from the position of the deflected light beam. The timing of apical rotation was compared with simultaneous recordings of electrocardiogram, LV pressure, and LV diameter measurements. An initial clockwise rotation (untwist) of 4 +/- 2 degrees (SD) occurred during isovolumic contraction followed by counterclockwise rotation (twisting) through ejection, reaching maximum apical rotation of -15 degrees just before the end of systole. Rapid untwisting during isovolumic relaxation was shown with near-complete dissipation of twist by the first one-third of the diastolic filling period. Caval occlusion caused a downward and leftward shift of the pressure-apical rotation loops, and more twist/untwist was seen to occur during the respective isovolumic contraction and relaxation periods. We conclude that this device provides precise timing and definition of rapid changes during isovolumic contraction and relaxation, confirms results obtained by more laborious methods, and provides an easy method to measure the dynamics of apical rotation continuously during interventions such as load changes.

Animals↗
PubMed1999

An optical device with variable astigmatic power.

A new variable power cross-cylinder lens set is described. It differs from the well known Stokes variable power cross-cylinder lens set, which is made of cylinder lenses of equal but opposite power, in that in the new variable power cross-cylinder lens set both lens elements are identical. These elements can be sphero cylindrical of any type and can be designed to give the same effect as a Stokes lens set or create a spherical bias or offset of a desired amount. The action of this lens set is analyzed using 3-dimensional refractive space.

Astigmatism↗
PubMed2004

Philosophical instruments and toys: optical devices extending the art of seeing.

Philosophical instruments were designed to examine phenomena experimentally, rather than by naturalistic observation alone. In the nineteenth century, some instruments were called philosophical toys because they provided popular amusement as well as experimental assistance. They were applied widely in natural philosophy, but attention here is directed particularly to manipulations of perceived space and time and their influence on art. One of the earliest instruments, which had a profound impact on art as well as science, was the camera obscura. It assisted image formation in art before it was applied as an analogy to the eye at the beginning of the seventeenth century. Later philosophical toys were used to address visual perception of motion and depth. Development was initially driven by the need for stimulus control so that the methods of physics could be applied to the study of perceptual phenomena. The principal instruments were invented in the first half of the nineteenth century, and they consisted of simple contrivances that manipulated time and space in ways that had not previously been appreciated. They included thaumatropes, phenakistoscopes, stroboscopes, anorthoscopes, stereoscopes, tachistoscopes, and chronoscopes. Several of these philosophical toys proved to be phenomenally popular, particularly when combined with photography.

History, 16th Century↗