CONVERSION OF WIDEBAND EM FREQUENCY RESPONSE TO TRANSIENT RESPONSE USING SEGMENTED TRANSFORMATION

Geophysics ◽  
1978 ◽  
Vol 43 (1) ◽  
pp. 189-193 ◽  
Author(s):  
M. W. Asten ◽  
S. K. Verma
Keyword(s):  
Frequency Domain ◽  
Continuous Wave ◽  
Primary Field ◽  
Analog Model ◽  
Response Curves ◽  
Input System ◽  
Transient Nature ◽  
Field Response ◽  
Different Types ◽  
Linear Ramp

Electromagnetic (EM) methods measure the distortions of a primary field which are caused by a sub‐surface conductor. The resultant field is recorded as a function of frequency or of time, depending upon the harmonic or transient nature of the primary field. The two different types of measurements thus recognized are frequency domain (or continuous‐wave) and time domain (transient or TEM) methods. Interpretation of EM data is possible by comparing field response with the analytic or experimental response of a heuristic model. Most of the interpretive developments have been done for the frequency domain technique, which is mathematically more tractable than the TEM technique when we consider generalized models possessing a conductive halo, over‐burden, or host rock. For such models, TEM response is more easily obtained from analog model experiments (e.g., Velekin and Bulgakov, 1967; Palacky, 1975). Response curves thus obtained, however, are dependent upon the shape of the excitation pulse which varies among the different transient EM systems available; e.g., the Input system (Barringer, 1962) uses a 1.1 msec half‐sine pulse, the Crone pulse EM system (Crone, 1975) uses a linear ramp pulse with 1.4 msec rise time, while the Russian MPP01 system (Velekin and Bulgakov, 1967) uses a 15 msec square step pulse.

Dose-response Curves in the Fibrin Plate Assay Fibrinolytic Activity of Proteases

1974 ◽  
Vol 32 (02/03) ◽  
pp. 356-365 ◽  
Author(s):  
F Haverkate ◽  
D. W Traas
Keyword(s):  
Dose Response ◽  
Fibrinolytic Activity ◽  
Enzyme Concentration ◽  
Response Curves ◽  
Agar Gel ◽  
Porcine Tissue ◽  
Plate Assay ◽  
Fibrin Plate ◽  
Different Types ◽  
Dose Response Curves

SummaryIn the fibrin plate assay different types of relationships between the dose of applied proteolytic enzyme and the response have been previously reported. This study was undertaken to determine whether a generally valid relationship might exist.Trypsin, chymotrypsin, papain, the plasminogen activator urokinase and all of the microbial proteases investigated, including brinase gave a linear relationship between the logarithm of the enzyme concentration and the diameter of the circular lysed zone. A similar linearity of dose-response curves has frequently been found by investigators who used enzyme plate assays with substrates different from fibrin incorporated in an agar gel. Consequently, it seems that this linearity of dose-response curves is generally valid for the fibrin plate assay as well as for other enzyme plate bioassays.Both human plasmin and porcine tissue activator of plasminogen showed deviations from linearity of semi-logarithmic dose-response curves in the fibrin plate assay.

Diacylglycerols and PMA induce actin polymerization and distinct shape changes in lymphocytes: relation to fluid pinocytosis and locomotion

1989 ◽  
Vol 93 (3) ◽  
pp. 457-465
Author(s):  
H.U. Keller ◽  
V. Niggli ◽  
A. Zimmermann
Keyword(s):  
Actin Polymerization ◽  
Shape Change ◽  
Second Messengers ◽  
Cell Periphery ◽  
Response Curves ◽  
Blood Lymphocytes ◽  
Different Types ◽  
Net Uptake ◽  
Very High ◽  
Shape Changes

Shape changes have been determined in human blood lymphocytes stimulated with OAG, diC8, PMA, colchicine or the hexapeptide fNLPNTL in short-term assays (30 min). Distinct types of shape-change responses were observed. Colchicine was active in generating a relatively small proportion of polarized lymphocytes (front-tail polarity). OAG, diC8 and PMA produced different types of shape change (non-polar cells with surface projections), and these were closely associated with an increase in actin polymerization and a shift of F-actin into the projections at the cell periphery. The diacylglycerols OAG and diC8 produced biphasic dose-response curves leading to rounding up of cells at very high stimulant concentrations. PMA produced no comparable biphasic response when tested over a much wider concentration range. Though the nonpolar cells with surface projections generated by OAG, diC8 or PMA showed vigorous shape changes, they lacked significant locomotor activity. alpha-Phorbol, 4 alpha-PDD, lumicolchicine or fNLPNTL were inactive. Small blood lymphocytes stimulated by OAG, diC8 or PMA showed a very small increase in the net uptake of FITC-dextran by fluid pinocytosis. Unlike neutrophils, which show a high net uptake, lymphocytes did not concentrate FITC-dextran in large granules, indicating that they do not develop a ‘storage’ compartment in the form of large vesicles. However, small fluorescent spots were consistently found in at least a fraction of blood lymphocytes. The results indicate that stimulated surface movement may be instrumental in fluid pinocytosis. Diacylglycerols may act as second messengers to induce pinocytosis, shape changes and altered actin polymerization in lymphocytes.

scholarly journals Characteristics of Factor VIII Related Protein in Different Types of von Willebrand’s Disease

1977 ◽  
Author(s):  
A. L. Bloom ◽  
I. R. Peake
Keyword(s):  
Factor Viii ◽  
Dose Response ◽  
Related Protein ◽  
Con A ◽  
Response Curves ◽  
Von Willebrand's Disease ◽  
Normal Plasma ◽  
Different Types ◽  
Dose Response Curves ◽  
Antigenic Reactivity

The antigenic, biochemical and biological reactions of factor VIII related protein were studied in normal plasma and in the plasma of patients with different types of von Willebrand’s disease (vWd). Antigenic reactivity was compared using the Laurell electroimmunoassay (LA) and an immunoradiometric assay (IRMA). Biochemical characteristics of factor VIII related antigen (FVIIIRAG) were compared by examining its electrophoretic mobility (EM) on two dimensional crossed Immunoelectrophoresis (2DCIE) and by determining its precipitation properties with the glycoprotein precipitant concanavalin A (Con A),Biological reactions were compared using the ristocetin cofactor (RiCoF) assay on fixed platelets and by determining procoagulant factor VIII (FVIIIC). In normal plasma the levels of FVIIIRAG measured by LA correlated with the IRMA and dose response curves were parallel. At a concentration of lmg/ml Con A completely precipitated FVIIIRAG. The biological activities, RiCoF anú FVIIIC, were normal and correlated with those of FVIIIRAG. In patients with vWd in whom levels of FVIIIRAG by LA were normal the EM by 2DCIE was increased. In these patients the dose-response curves of the IRMA were not parallel to normal, FVIIIRAG was not precipitated normally by Con A and the RiCoF activity was reduced. Similar findings were observed in some patients with “typical” intermediate vWd in whom the plasma levels of FVIIIRAG were too low to determine EM, In other patients with vWd the dose response curves of the IRMA were parallel. The results suggest that the non-parallel dose response curves of the IRMA were due to the presence of abnormal FVIIIRAG and were consistent with variations of antigenic reactivity or binding sites in these patients.

Experimental Comparison of Continuous-Wave and Frequency-Domain Fluorescence Tomography in a Commercial Multi-Modal Scanner

2015 ◽  
Vol 34 (6) ◽  
pp. 1197-1211 ◽  
Author(s):  
Yujie Lu ◽  
Chinmay D. Darne ◽  
I-Chih Tan ◽  
Banghe Zhu ◽  
Ryan Rightmer ◽  
...  
Keyword(s):  
Frequency Domain ◽  
Continuous Wave ◽  
Experimental Comparison ◽  
Fluorescence Tomography

Magnetic resonance guided optical spectroscopy imaging of human breast cancer using a combined frequency domain and continuous wave approach

2012 ◽  
Author(s):  
Michael A. Mastanduno ◽  
Scott C. Davis ◽  
Shudong Jiang ◽  
Roberta diFlorio-Alexander ◽  
Brian W. Pogue ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Magnetic Resonance ◽  
Frequency Domain ◽  
Optical Spectroscopy ◽  
Human Breast Cancer ◽  
Continuous Wave ◽  
Human Breast ◽  
Wave Approach

scholarly journals Frequency Shifting Model for Diffuse Optical Tomography

2021 ◽  
Author(s):  
Huseyin Ozgur Kazanci
Keyword(s):  
Inverse Problem ◽  
Frequency Domain ◽  
Continuous Wave ◽  
Model Problem ◽  
Optical Tomography ◽  
Diffuse Optical Tomography ◽  
Solution Space ◽  
Forward Model ◽  
Problem Solution ◽  
Frequency Shifting

Abstract Diffuse Optical Tomography (DOT) imaging technique has been interesting research field for researchers since it has uncertainties in the solution space. DOT modality is unsolved scientific problem. Inverse problem solution and image reconstruction has never been in its best quality. Reconstructed images have low spatial resolution. Scattering nature of diffusive light is the obscuring effect for DOT modality. DOT has 3 functional sub-branches which of these are Continuous Wave (CW), Time-Resolved (TR), and Frequency-Domain (FD). In this work, one new approach to Frequency Domain Diffuse Optical Tomography (FDDOT) biomedical optic imaging modality is presented to the readers. Frequency Shifting data were added to the forward model problem which basically has source-detector couplings and number of imaging voxels. 100 MHz center core light modulation frequency was selected. 169 source-detector matches were used on back-reflected imaging geometry. Absorption coefficient ma was selected 0.1 cm− 1. Scattering coefficient µs was selected 100 cm− 1. 1 micrometer x, y, z cartesian grid coordinates were used in each direction for imaging tissue-like simulation media. The total of 100 frequency shift was added to the forward model problem which has 5 Hz frequency step. 2 inclusion objects were embedded inside the imaging simulation phantom. 2 inclusion images were successfully reconstructed with the low contrast to noise ratio (CNR) error and position error (PE). Frequency shifting technique is first applied for FDDOT here. This technique has increased the total number of equations in the forward model problem; hence it is helping to solve the inverse problem. In this work, the positive effect of using multi frequency methodology was observed. Differentiation of 2 embedded inclusions was successfully completed and illustrated in this work.

scholarly journals Steganographical Techniques in Hiding Text Images – System

2019 ◽  
Vol 8 (2) ◽  
pp. 6535-6537
Keyword(s):  
Frequency Domain ◽  
Essential Role ◽  
Vital Role ◽  
Secret Data ◽  
Unauthorized Access ◽  
The World ◽  
Different Types ◽  
Image Technique ◽  
Audio Video ◽  
Text Images

In this era, internet has become a widespread entity all over the world. Sharing and communicating images, video contributes an essential role in this scientific era. In the meanwhile, secure transition of data has indeed become a major issue. Steganography is one of technology that contributes a vital role in protecting the secret data against an unauthorized access. In this type, secret data can be concealed into a cover file that includes audio, video, text and also image. In this paper, we propose different types of steganography methods for secure transfer of data in a confidential manner. The paper also explores stenographical techniques in terms of text, image and audio. The proposed work compares and discusses the stenographical methods in spatial domain, frequency domain derived under the image technique

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