scholarly journals Veins Depth Estimation Using Diffused Reflectance Parameter

2020 ◽  
Vol 10 (22) ◽  
pp. 8238
Author(s):  
Rab Nawaz Jadoon ◽  
Aamir Shahzad ◽  
Syed Ayaz Ali Shah ◽  
Muhammad Amir Khan ◽  
Tallha Akram ◽  
...  
Keyword(s):  
Monte Carlo ◽  
Light Propagation ◽  
Near Infrared ◽  
Infrared Imaging ◽  
Monte Carlo Model ◽  
Depth Estimation ◽  
Operating Conditions ◽  
Mathematical Representation ◽  
Depth Information ◽  
Optical Parameters

In order to perform the standard Intravenous (IV) catheterization, subcutaneous veins must be localized. It is a difficult task, especially in the cases when veins are hard to localize. The factors which affect the veins localization process are the physiological characteristics of patients, mainly darker skin tone, scars, hair, dehydration and low blood pressure. With the help of Near Infrared imaging, subcutaneous veins can be envisioned. This is due to the higher absorption of NIR light energy by Hemoglobin (Hb) found in the veins. Besides a superficial view, the veins depth information is also important in order to avoid their rupture by piercing through the walls during IV catheterization process. Diffused reflectance, measured with a camera sensor, can be used for the depth estimation of blood vessels. In this paper, a method to measure the depth of veins using diffused reflectance parameter, is presented. The well-known Monte Carlo model of light propagation in human tissues is used for the mathematical representation. A four-layered skin model is presented with varying vessel depths to describe the diffused reflectance of light while propagating inside skin tissues. The results are validated with Monte Carlo simulations for light propagation in layered medium. A sensitivity analysis of proposed method is also performed with a 5% alteration in the optical parameters of skin due to the change in operating conditions. The results showed a marginal error of maximum value 6.23% in vessel depth estimation using the standard optical parameters, 1.6% for −5% and 10.74% for +5% change in optical parameters.

scholarly journals Near-Infrared Spatial Self-Phase Modulation in Ultrathin Niobium Carbide Nanosheets

2021 ◽  
Vol 9 ◽  
Author(s):  
Si Xiao ◽  
Yi-lin He ◽  
Yu-lan Dong ◽  
Yi-duo Wang ◽  
Li Zhou ◽  
...  
Keyword(s):  
Phase Modulation ◽  
Light Propagation ◽  
Near Infrared ◽  
Niobium Carbide ◽  
Infrared Region ◽  
Hybrid Structure ◽  
Optical Parameters ◽  
Self Phase Modulation ◽  
Non Linear ◽  
Linear Optical

Spatial self-phase modulation (SSPM) as a purely coherent non-linear optical effect (also known as Kerr effect) can support strong broadband phase modulation, which is essential for all-optical applications. Besides this, the increasing use of two-dimensional (2D) materials opens up new prospects in this field of research. In this work, we report a broadband SSPM response from 2D transition metal carbonitrides (MXenes) and Nb2C, arising in the near-infrared (1,550 nm) range. Based on the SSPM measurements of few-layer Nb2C nanosheets, the third-order non-linear optical parameters of Nb2C, including the non-linear refractive index n2 and susceptibility χ(3), were determined at 400, 800, 1,300, and 1,550 nm. Moreover, the physics mechanism of the dynamic formation process of SSPM diffraction rings was exploited. The formation time of SSPM diffraction rings can be divided into two typical parts which correspond to the polarization and reorientation of 2D Nb2C nanosheets. As a proof of concept, we demonstrate the nonreciprocal light propagation at wavelengths of 1,300 and 1,550 nm by constructing an Nb2C/water hybrid structure. Our results reveal strong optical phase modulation of Nb2C in the infrared region, thus showing the great potential of MXene materials for use in passive photonic devices.

Monte Carlo simulation of light propagation in adult brain: influence of tissue blood content and indocyanine green

2008 ◽  
Vol 16 (2) ◽  
Author(s):  
P. Niederer ◽  
R. Mudra ◽  
E. Keller
Keyword(s):  
Monte Carlo ◽  
Indocyanine Green ◽  
Light Propagation ◽  
Near Infrared ◽  
Human Head ◽  
Adult Brain ◽  
Blood Content ◽  
Representative Model ◽  
Adult Head ◽  
Clinically Significant

AbstractNear-infrared spectroscopy (NIRS), applied to a human head, is a noninvasive method in neurointensive care to monitor cerebral hemodynamics and oxygenation. The method is particularly powerful when it is applied in combination with indocyanine green (ICG) as a tracer substance. In order to assess contributions to the measured optical density (OD) which are due to extracerebral circulation and disturb the clinically significant intracerebral signals, we simulated the light propagation in an anatomically representative model of the adult head derived from MRI measurements with the aid of Monte Carlo methods. Since the measured OD signal depends largely on the relative blood content in various transilluminated tissues, we weighted the calculated densities of the photon distribution under baseline conditions within the tissues with the changes and aberrations of the relative blood volumes which we expect to prevail under physiological conditions. Furthermore, the influence of the IGC dye as a tracer substance was assessed. We conclude that up to about different 70% of the measured OD signal may have its origin in the tissues of interest under optimal conditions, which is mainly due to the extrapolated high relative blood content of brain tissue along with the influence of ICG.

Computational Investigation of Selective MOVPE of AlxGa1-xAs in Presence of Hcl

2001 ◽  
Vol 701 ◽  
Author(s):  
Maria Nemirovskaya ◽  
Carlo Cavallotti ◽  
Klavs Jensen
Keyword(s):  
Fluid Dynamics ◽  
Monte Carlo ◽  
Transition State ◽  
Gas Phase ◽  
Kinetic Monte Carlo ◽  
Monte Carlo Model ◽  
Operating Conditions ◽  
Morphology Evolution ◽  
Computational Investigation ◽  
Dynamics Simulations

ABSTRACTThe deposition of AlGaAs in the presence of HCl was investigated at the macroscopic and mesoscopic scales. Fluid dynamics simulations were first performed in order to study the dependence of the deposition rate on the operating conditions. Unknown gas phase and surface kinetic parameters were estimated by quantum chemistry and transition state computations. The fluxes of all species to the surface were thus computed and provided the input to a kinetic Monte Carlo model used to investigate the morphology evolution of the film.

Probabilistic evaluation of ammonia toxicity in Milwaukee's Outer Harbor

2006 ◽  
Vol 53 (1) ◽  
pp. 109-116
Author(s):  
C.S. Melching ◽  
V. Novotny ◽  
J.B. Schilling
Keyword(s):  
Water Quality ◽  
Monte Carlo ◽  
Monte Carlo Model ◽  
Quality Criteria ◽  
Operating Conditions ◽  
Ammonia Toxicity ◽  
Quality Data ◽  
Water Quality Criteria ◽  
Water Quality Data ◽  
Probabilistic Evaluation

Water-quality models that are simple yet sound and reliable and that correspond to water-quality criteria that include magnitude, frequency, and duration components are needed. Monte Carlo models are developed on the basis of available flow and water-quality data and a deterministic water-quality model appropriate for the problem at hand and the data available. Monte Carlo models yield time series and probability distributions of constituents of interest in conformance with water-quality criteria. The application of a Monte Carlo model to the probabilistic evaluation of ammonia toxicity in Milwaukee's Outer Harbor is presented here. Under typical operating conditions for the Jones Island Wastewater Treatment Plant, ammonia toxicity was found to not be a problem for the Outer Harbor. The Monte Carlo model then was used to determine effluent limits that would meet the ammonia toxicity criteria.

scholarly journals A Parallel Mode Optimized GPU Accelerated Monte Carlo Model for Light Propagation in 3-D Voxelized Bio-Tissues

IEEE Access ◽  
2019 ◽  
Vol 7 ◽  
pp. 81593-81598
Author(s):  
Xiang Fang ◽  
Hao Li ◽  
Weichao Liu ◽  
Yingxin Li ◽  
Ting Li
Keyword(s):  
Monte Carlo ◽  
Light Propagation ◽  
Monte Carlo Model ◽  
Parallel Mode
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