Colours and anomalies of skin: diploma 2015

Afin de suivre et d’analyser l’évolution, lors de traitement ou pas, de lésions de la peau (grains de beauté, plaies, tâches de sénescence, coup de soleil …), nous avons développé une caméra portable munie d’une illumination multispectrale capable d’envoyer les images sur un serveur dédié et d’analyser ces imagesWe developed a handheld camera with multispectral illumination to take pictures and to analyse anomalies of skin. The fields of use are: a) analysing and tracking skin lesions such as naevi or wounds, b) studying influence of creams.Das Ziel ist die Entwicklung einer portablen Kamera mit multispektraler Beleuchtung zur Aufnahme und Analyse von Anomalien der Haut. Anwendungsbereiche sind: a) Analyse und Verfolgung von Muttermalen und Wunden, b) Untersuchung von Einfluss von Creme

Bioluminescence: diplôme 2015

Dans le cadre du projet européen BRAAVOO, qui vise à mesurer les concentrations de différents polluants présents dans la mer, nous développons un lecteur de bioluminescence embarqué dans une bouée

Multispektrale Fotoaufnahme für die Detektion von Hautkrebs

Since skin cancer is the most common kind of cancer in Switzerland, its detection and treatment consumes a high amount of time and money. Due to subjective diagnosis by eye, based on experience of the dermatologist, a surgical operation will take place - or not. Here the product can show his strengths. Substantiate the decision of the dermatologist, or maybe indicate another view. It will be possible to avoid unnecessary surgery, sparing a lot of trouble. A meeting with Dr. Gianadda helped to understand the problem, and led the project into the right direction. We got a view on the FotoFinder, which will be described on the next chapter

Ocular Blood Flow Measured Noninvasively in Zero Gravity

In spaceflight or a reduced-gravity environment, bodily fluids shift to the upper extremities of the body. The pressure inside the eye, or intraocular pressure, changes significantly. A significant number of astronauts report changes in visual acuity during orbital flight. To date this remains of unknown etiology. Could choroidal engorgement be the primary mechanism and a change in the curvature or shape of the cornea or lens be the secondary mechanism for this change in visual acuity? Perfused blood flow in the dense meshwork of capillaries of the choroidal tissue (see the preceding illustration) provides necessary nutrients to the outer layers of the retina (photoreceptors) to keep it healthy and maintain good vision. Unlike the vascular system, the choroid has no baroreceptors to autoregulate fluid shifts, so it can remain engorged, pushing the macula forward and causing a hyperopic (farsighted) shift of the eye. Experiments by researchers at the NASA Glenn Research Center could help answer this question and facilitate planning for long-duration missions. We are investigating the effects of zero gravity on the choroidal blood flow of volunteer subjects. This pilot project plans to determine if choroidal blood flow is autoregulated in a reduced-gravity environment

Choroidal Blood Flow Regulation after Posture Change or Isometric Exercise in Men with Obstructive Sleep Apnea Syndrome

PURPOSE. Obstructive sleep apnea (OSA) syndrome generates hypertension, atherosclerosis, and endothelial and autonomic dysfunction, which may mutually interact with ocular vascular regulation. Exercise and posture changes can be used to manipulate blood pressure, ocular perfusion pressure (OPP), or both. It was hypothesized that choroidal vascular reactivity in response to isometric exercise and posture changes could be altered in OSA patients. METHODS. Healthy men were matched 1:1 for body mass index, sex, and age with patients with newly diagnosed OSA without cardiovascular comorbidities. All subjects underwent sleep studies and cardiovascular phenotyping (24-hour blood pressure monitoring, arterial stiffness measurements, and cardiac and carotid echography). Choroidal reactivity was assessed by laser Doppler flowmetry, which measured subfoveal choroidal blood flow. RESULTS. During exercise, blood pressure parameters increased significantly within the same range, with a similar profile over time in OSA patients and control subjects. A significant linear relationship (P ϭ 0.0003) was noted between choroidal vascular resistance and the OPP changes during exercise in OSA patients and control subjects. From the sitting to the supine position, a significant decrease in mean arterial pressure occurred in both groups (10.9%-13.4%; P Ͻ 0.001). In both populations, no significant change in choroidal blood flow or vascular resistance was found during the posture change. Choroidal blood flow responses to exercise and posture changes were unchanged after 6 to 9 months of continuous positive airway pressure treatment. CONCLUSIONS. This study strongly suggests that the regulation of choroidal blood flow, which depends on the orthosympathetic and parasympathetic systems, is unaltered in men with OSA who have no comorbidities. (ClinicalTrials.gov number, NCT00874913.) (Invest Ophthalmol Vis Sci. 2011; 52:9489 -9496

Conception of a small reflectometer to measure the reflectance spectrum of the iris

Optical research is a domain which has made great progress. For example, at the beginning of February 2008, an artificial implant was fixed on the retina of a blind patient in Geneva, Switzerland. With this microelectronical device, this patient will be able to recover elementary vision. But the research is still in development. The eye is a very complicated organ which will give further information through new optical and biological studies. The aim of this project is to know more about the iris and its properties especially with the iris reflectance caused by the melanin. This pigment concentration in the different layers of the iris gives the commonly called "color of the eye". An optical system has been developped around a spectrometer to measure the reflectance spectrum of the iris. This compact system uses a combination of leds for the illumination and a USB4000 spectrometer working with a spectral measurement software running on an Apple laptop

Laser Doppler Flowmetry versatile acquisition system with low quantization error

The Laser Doppler Flowmetry (LDF) is a non-invasive technique used to evaluate blood perfusion of various human tissues like the skin or the fundus of the eye. It is based on the scattering of light on moving red blood cells in tissue. Frequency shifted scattered light is detected and provide an electrical signal. Physical models for LDF use the DC and AC components of this signal. If AC is small relative to the DC, digitalization becomes an issue, and if more than two LDF signal acquisitions and analysis have to be done simultaneously, the device becomes expensive and bulky. We propose here a versatile and inexpensive acquisition system, which overcomes quantization errors issue by first separating DC from AC, then amplifying AC and finally recombining both signals before digitalization. We designed an analog circuit combined with a 12 bit analog-to-digital converter, a microcontroller unit and a Raspberry Pi2 (Rpi2) for the signal processing. Results are accessed remotely from the Rpi2 through HTTP protocol. Multiple systems can easily be used simultaneously for multichannel acquisitions