Lymph Node Characterization in Vivo Using Endoscopic Ultrasound Spectrum Analysis With Electronic Array Echo Endoscopes

Our purpose was to demonstrate the use of radiofrequency spectral analysis to distinguish between benign and malignant lymph nodes with data obtained using electronic array echo endoscopes, as we have done previously using mechanical echo endoscopes. In a prospective study, images were obtained from eight patients with benign-appearing lymph nodes and 11 with malignant lymph nodes, as verified by fine-needle aspiration. Midband fit, slope, intercept, correlation coefficient, and root-mean-square (RMS) deviation from a linear regression of the calibrated power spectra were determined and compared between the groups. Significant differences were observable for mean midband fit, intercept, and RMS deviation (t test P \u3c 0.05). For benign (n = 16) vs. malignant (n = 12) lymph nodes, midband fit and RMS deviation provided classification with 89 % accuracy and area under receiver operating characteristic (ROC) curve of 0.95 based on linear discriminant analysis. We concluded that the mean spectral parameters of the backscattered signals from electronic array echo endoscopy can provide a noninvasive method to quantitatively discriminate between benign and malignant lymph nodes

Role of short-pulse laser for detection and differentiation of cancer stages and benign lesion within human skin

The present study pertains to theoretical evaluation of various skin lesions using reflectance mode short-pulse (SP) laser technique, which has been assumed to be operating within the therapeutic optical window of 600-1300 nm. The skin and lesions have been modeled based on anatomic details and optical properties available in the literature. Whereas, the different lesion stages have been modeled according to the American Joint Committee for Cancer Staging guidelines. The numerical simulation of transient radiative transfer equation has been carried out with the aid of finite volume method (used for resolving angular and spatial distributions) and backward differencing formula (used for time discretization). The anisotropic scattering of diffuse light due to the attenuation of incident laser light has been demonstrated using Henyey-Greenstein scattering phase function. The numerical analysis revealed that the associated changes in reflected radiative signatures due to the change in tissue properties (i.e. for different form of skin lesions) and conditions (i.e., growth features) can be a means to detect and differentiate the skin cancer.Papers presented to the 12th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, Costa de Sol, Spain on 11-13 July 2016

Pressure induced martensitic transition, magnetocaloric and magneto-transport properties in Mn-Ni-Sn Heusler alloy

Sem informaçãoIn this work, we report the effect of hydrostatic pressure (P) on the martensitic transition in Mn50Ni40Sn10 Heusler alloy using the magnetization and electrical resistivity measurements. Martensitic transition temperature (T-M) is found to shift significantly to higher temperatures with the application of pressure, which reflects the stabilization of the martensite phase. On the other hand, T-M shifts to lower temperatures with magnetic field, which implies the stabilization of the austenite phase. The estimated rate of change of martensitic transition temperature with pressure (dT(M)/dP) for the present alloy is similar to 4.6 K/kbar. The alloy shows a maximum negative magnetoresistance (MR) of 9.6% for P = 4 kbar at the martensitic transition. A large isothermal magnetic entropy change (Delta S-M) of 16.6 J/kg.K and a refrigerant capacity (RC) of similar to 146 J/kg are observed at TM under ambient pressure. Both quantities are found to decrease with the increase of pressure. The values of Delta S-M and adiabatic temperature change (Delta T-ad), calculated from heat capacity measurements are similar to 11.3 J/kg. K and -3.4 K respectively for 50 kOe field change. The observed pressure and field dependence results have been explained using the Clausius-Clapeyron equation. The combined effect of pressure and field on the martensitic transition is also discussed.48717Sem informaçãoSem informaçãoSem informaçãoAuthors acknowledge BRNS-DAE for the financial assistance granted through a sponsored research project. J. Sharma would like to acknowledge the SERB-DST Govt. of India for the financial assistance granted through a NPDF project. The work on pressure dependent electrical properties was conducted by NTU-HUJ-BGU Nanomaterials for Energy and Water Management Programme under the Campus for Research Excellence and Technological Enterprise (CREATE), that is supported by the National Research Foundation, Prime Minister's Office, Singapore. Author would like to acknowledge Dr. S. Shanmukharao Samatham for important discussion

Magnetocaloric properties and critical behavior of high relative cooling power FeNiB nanoparticles

Low cost magnetocaloric nanomaterials have attracted considerable attention for energy efficient applications. We report a very high relative cooling power (RCP) in a study of the magnetocaloric effect in quenched FeNiB nanoparticles. RCP increases from 89.8 to 640 J kg−1 for a field change of 1 and 5 T, respectively, these values are the largest for rare earth free iron based magnetocaloric nanomaterials. To investigate the magnetocaloric behavior around the Curie temperature (TC ), the critical behavior of these quenched nanoparticles was studied. Detailed analysis of the magnetic phase transition using the modified Arrott plot, Kouvel-Fisher method, and critical isotherm plots yields critical exponents of β = 0.364, γ = 1.319, δ = 4.623, and α = −0.055, which are close to the theoretical exponents obtained from the 3D-Heisenberg model. Our results indicate that these FeNiB nanoparticles are potential candidates for magnetocaloric fluid based heat pumps and low grade waste heat recovery.Published versio

Characterization of the Pancreas in Vivo Using EUS Spectrum Analysis with Electronic Array Echoendoscopes

Background Spectral analysis of the radiofrequency (RF) signals that underlie grayscale EUS images has been used to provide quantitative, objective information about tissue histology. Objective Our purpose was to validate RF spectral analysis as a method to distinguish between chronic pancreatitis (CP) and pancreatic cancer (PC). Design and Setting A prospective study of eligible patients was conducted to analyze the RF data obtained by using electronic array echoendoscopes. Patients Pancreatic images were obtained by using electronic array echoendoscopes from 41 patients in a prospective study, including 15 patients with PC, 15 with CP, and 11 with a normal pancreas. Main Outcome Measurements Midband fit, slope, intercept, correlation coefficient, and root mean square deviation from a linear regression of the calibrated power spectra were determined and compared among the groups. Results Statistical analysis showed that significant differences were observable between groups for mean midband fit, intercept, and root mean square deviation (t test, P \u3c .05). Discriminant analysis of these parameters was then performed to classify the data. For CP (n = 15) versus PC (n = 15), the same parameters provided 83% accuracy and an area under the curve of 0.83. Limitations Moderate sample size and spatial averaging inherent in the technique. Conclusions This study shows that mean spectral parameters of the backscattered signals obtained by using electronic array echoendoscopes can provide a noninvasive method to quantitatively discriminate between CP and PC