Search results for "Diode"
showing 10 items of 469 documents
Determination of chromophore distribution in skin by spectral imaging
2012
Possibilities to determine chromophore distribution in skin by spectral imaging were explored. Simple RGB sensor devices were used for image acquisition. Totally 200 images of 40 different bruises of 20 people were obtained in order to map chromophores bilirubin and haemoglobin. Possibilities to detect water in vitro and in vivo were estimated by using silicon photodetectors and narrow band LEDs. The results show that it is possible to obtain bilirubin and haemoglobin distribution maps and observe changes of chromophore parameter values over time by using a simple RGB imaging device. Water in vitro was detected by using differences in absorption at 450 nm and 950 nm, and 650 nm and 950 nm.
Mandibular destructive radiolucent lesion: the first sign of multiple myeloma
2016
The occurrence of a mandibular lesion as the first sign of multiple myeloma (MM) is uncommon. This report describes a case of MM diagnosed because of a mandibular lesion. A 62-year-old woman presented a destructive radiolucent lesion in the right mandibular ramus. The lesion caused rupture of the anterior cortical bone and extended from the retromolar area to the coronoid process. An incisional biopsy was performed. Histopathological examination revealed numerous pleomorphic plasma cells, some with binucleated nuclei. The tumor cells showed kappa light-chain restriction. Bone marrow biopsy showed findings of massive infiltration of neoplastic plasma cells, besides lesions in the vertebrae. …
Analysis of radiolucent gallstones by computed tomography for in vivo estimation of stone components.
1990
. Successful oral litholytic and other non-operative therapies of gallstones require exact determination of the stone components. Since computed tomography (CT) provides highly sensitive measurement of density, we performed a study to evaluate whether CT measurement of stone density allows a prediction of the composition of radiolucent gallstones. Twenty-eight patients presenting with 29 radiolucent gallbladder (n= 17) or common bile duct stones (n=12) were included. Prior to operative or endo-scopic therapy the attenuation values (Hounsfield Units, HU) were assessed in vivo by CT under standardized conditions (Somatom II, 125 KV, 130 mAs). After surgical or endoscopic stone removal the con…
Plain film, CT and MRI sensibility in the evaluation of intraorbital foreign bodies in an in vitro model of the orbit and in pig eyes.
2000
Detection and characterization of intraorbital foreign bodies (IFB) is fundamental in acute trauma setting, preventing inflammatory sequelae or complications related to IFB movements when a MRI study is planned. Papers concerning plain film and CT sensibility in IFB detection show controversial results. For this reason we investigated plain film, CT and MRI sensibility in the evaluation of IFB. For an in vitro model, specimens of dry and fresh wood, glass, iron, plastic and graphite were immersed in animal lard and in a 0.9 % sodium chloride plus 3.5 g/dl human serum albumin solution. Specimens of different size and nature where also implanted into enucleated pig eyes. Air bubbles were intr…
RGB mapping of hemoglobin distribution in skin
2011
An experimental RGB imaging system based on commercial color camera was constructed, and its potential for mapping of hemoglobin distribution in skin was studied. Two types of LEDs (RGB and white “warm” LEDs) were compared as illuminators for acquiring images of vascular and pigmented skin malformations. A novel approach for studies of skin capillary refill by RGB analysis has been proposed and discussed.
Enhancing Light Emission in Interface Engineered Spin-OLEDs through Spin-Polarized Injection at High Voltages
2019
The quest for a spin-polarized organic light-emitting diode (spin-OLED) is a common goal in the emerging fields of molecular electronics and spintronics. In this device, two ferromagnetic (FM) electrodes are used to enhance the electroluminescence intensity of the OLED through a magnetic control of the spin polarization of the injected carriers. The major difficulty is that the driving voltage of an OLED device exceeds a few volts, while spin injection in organic materials is only efficient at low voltages. The fabrication of a spin-OLED that uses a conjugated polymer as bipolar spin collector layer and ferromagnetic electrodes is reported here. Through a careful engineering of the organic/…
Calibration of the underground muon detector of the Pierre Auger Observatory
2021
To obtain direct measurements of the muon content of extensive air showers with energy above $10^{16.5}$ eV, the Pierre Auger Observatory is currently being equipped with an underground muon detector (UMD), consisting of 219 10 $\mathrm{m^2}$-modules, each segmented into 64 scintillators coupled to silicon photomultipliers (SiPMs). Direct access to the shower muon content allows for the study of both of the composition of primary cosmic rays and of high-energy hadronic interactions in the forward direction. As the muon density can vary between tens of muons per m$^2$ close to the intersection of the shower axis with the ground to much less than one per m$^2$ when far away, the necessary bro…
Modification of a commercial atomic force microscopy for low-noise, high-resolution frequency-modulation imaging in liquid environment.
2011
A key issue for high-resolution frequency-modulation atomic force microscopy imaging in liquids is minimizing the frequency noise, which requires a detailed analysis of the corresponding noise contributions. In this paper, we present a detailed description for modifying a commercial atomic force microscope (Bruker MultiMode V with Nanoscope V controller), aiming at atomic-resolution frequency-modulation imaging in ambient and in liquid environment. Care was taken to maintain the AFMs original stability and ease of operation. The new system builds upon an optimized light source, a new photodiode and an entirely new amplifier. Moreover, we introduce a home-built liquid cell and sample holder …
THE SILICON PHOTOMULTIPLIER:AN IN-DEPTH ANALYSIS IN THE CONTINUOUS WAVE REGIME
2014
The Silicon Photomultiplier (SiPM) is a novel solid state photon counting detector consisting of a parallel array of avalanche photodiodes biased beyond their breakdown voltage. It has known a fast development in the last few years as a possible alternative to vacuum photomultiplier tubes (PMTs) and conventional avalanche photodiodes (APDs). Indeed, current research in photodetectors is directed toward an increasing miniaturization of the pixel size, thus both improving the spatial resolution and reducing the device dimensions. SiPMs show high photon detection efficiency in the visible and near infrared range, low power consumption, high gain, ruggedness, compact size, excellent single-phot…
Blue Emitting Organic Light Emitting Diodes
2019
Organic light emitting diodes (OLEDs) [1] can be fabricated on a range of materials such as glass, silicon or flexible plastic substrates. This can be exploited for the realization of integrated OLED-based fluorescence chemical sensors [2] and microfluidic systems [3] for application in areas such as biotechnology, life sciences, pharmaceuticals, public health and defense. These devices hold promises to be cost effective, ultra-compact (including the possibility to be fabricated into large bidimensional arrays), and capable to handle smaller sample volumes in order to achieve high throughput. Blue light is advantageous because it is strongly absorbed by most sensing molecules attached to bi…