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Sample records for a-150 tissue equivalent

  1. Composition of A-150 tissue-equivalent plastic.

    PubMed

    Smathers, J B; Otte, V A; Smith, A R; Almond, P R; Attix, F H; Spokas, J J; Quam, W M; Goodman, L J

    1977-01-01

    In recent years, the use of tissue-equivalent materials has become quite common in fast-neutron dosimetry, with the A-150 plastic developed by Shonka et al. probably the most popular. Information on this specific plastic is scantily reported in the literature and as a consequence a preponderance of authors unknowingly reference an article by Shonka describing an early version of a tissue substitute plastic but having a different elemental composition than the present A-150 formulation. We have reviewed the results of 21 chemical analyses which have occurred over a time span of four years on a total of 14 samples of A-150 plastic and based on these data and the formulation of the plastic, have arrived at a suggested composition for A-150 tissue-equivalent plastic. The ambiguities of water absorption by nylon, one of the components of the plastic, and the uncertainty this reflects in the composition of the plastic were evaluated. PMID:840195

  2. Application of A150-plastic equivalent gases in microdosimetric measurements

    SciTech Connect

    DeLuca, P.M. Jr.; Higgins, P.D.; Pearson, D.W.; Schell, M.; Attix, F.H.

    1981-01-01

    Neutron dosimetry measurements with ionization chambers, for the most part, employ tissue equivalent plastic-walled cavities (Shonka A150) filled with either air or a methane-base tissue-like gas. The atomic composition of TE-gas and A150 plastic are not matched and are quite dissimilar from muscle. Awschalom and Attix (1980) have partially resolved the problem by formulating a novel A150-plastic equivalent gas. This establishes a homogeneous wall-gas cavity dosimeter for neutron measurements and confines the necessary corrections to the applications of kerma ratios. In this report, we present measurements of applications of two A150-plastic equivalent gases in a low pressure spherical proportional counter. Gas gains and alpha-particle resolutions were determined. For these A150-mixtures as well as a methane-based TE-gas and an Ar-CO/sub 2/ mixture, we report measurements of event size distributions from exposure to a beam of 14.8 MeV neutrons.

  3. Tissue equivalent proportional counter neutron monitor

    SciTech Connect

    Smith, R.C.; Strode, J.N.

    1980-06-01

    The Tissue Equivalent Proportional Counter (TEPC) is a sensitive area monitoring instrument that can be used either in place at fixed locations or as a portable neutron exposure measuring device. The system monitors low levels of neutron radiation exposure and has the capability of accurately measuring neutron exposure rates as low as 0.1 mrem/hr. The computerized analysis system calculates the quality factor which is important for situations where the neutron to gamma ratio may vary significantly and irregularly such as in fuel fabrication or handling facilities.

  4. Response of a tissue equivalent proportional counter to neutrons

    NASA Technical Reports Server (NTRS)

    Badhwar, G. D.; Robbins, D. E.; Gibbons, F.; Braby, L. A.

    2002-01-01

    The absorbed dose as a function of lineal energy was measured at the CERN-EC Reference-field Facility (CERF) using a 512-channel tissue equivalent proportional counter (TEPC), and neutron dose equivalent response evaluated. Although there are some differences, the measured dose equivalent is in agreement with that measured by the 16-channel HANDI tissue equivalent counter. Comparison of TEPC measurements with those made by a silicon solid-state detector for low linear energy transfer particles produced by the same beam, is presented. The measurements show that about 4% of dose equivalent is delivered by particles heavier than protons generated in the conducting tissue equivalent plastic. c2002 Elsevier Science Ltd. All rights reserved.

  5. Tissue equivalency of phantom materials for neutron dosimetry in proton therapy

    SciTech Connect

    Dowdell, Stephen; Clasie, Ben; Wroe, Andrew; Guatelli, Susanna; Metcalfe, Peter; Schulte, Reinhard; Rosenfeld, Anatoly

    2009-12-15

    Purpose: Previous Monte Carlo and experimental studies involving secondary neutrons in proton therapy have employed a number of phantom materials that are designed to represent human tissue. In this study, the authors determined the suitability of common phantom materials for dosimetry of secondary neutrons, specifically for pediatric and intracranial proton therapy treatments. Methods: This was achieved through comparison of the absorbed dose and dose equivalent from neutrons generated within the phantom materials and various ICRP tissues. The phantom materials chosen for comparison were Lucite, liquid water, solid water, and A150 tissue equivalent plastic. These phantom materials were compared to brain, muscle, and adipose tissues. Results: The magnitude of the doses observed were smaller than those reported in previous experimental and Monte Carlo studies, which incorporated neutrons generated in the treatment head. The results show that for both neutron absorbed dose and dose equivalent, no single phantom material gives agreement with tissue within 5% at all the points considered. Solid water gave the smallest mean variation with the tissues out of field where neutrons are the primary contributor to the total dose. Conclusions: Of the phantom materials considered, solid water shows best agreement with tissues out of field.

  6. Measurement of the charged particle spectra from neutron irradiated tissue-equivalent plastic

    SciTech Connect

    Earls, L.M.

    1981-01-01

    The charged particle spectra from the 49 MeV deuteron on beryllium neutron beam onto Shonka A-150 tissue-equivalent plastic has been measured as a function of off-axis angle from 10/sup 0/ to 90/sup 0/. Particle detection was accomplished by silicon detectors in a detector telescope array. A ..delta..E-E algorithm was used to identify particles. Average particle energies for protons, deuterons, and alpha particles have been calculated and compared with calculations made by Wells. Certain discrepancies between Wells' slowing down spectra and the detected charged particle spectra have been observed.

  7. A study of a tissue equivalent gelatine based tissue substitute

    SciTech Connect

    Spence, J.L.

    1992-11-01

    A study of several tissue substitutes for use as volumetric dosimeters was performed. The tissue substitutes studied included tissue substitutes from previous studies and from ICRU 44. The substitutes were evaluated for an overall match to Reference Man which was used as a basis for this study. The evaluation was based on the electron stopping power, the mass attenuation coefficient, the electron density, and the specific gravity. The tissue substitute chosen also had to be capable of changing from a liquid into a solid form to maintain an even distribution of thermoluminesent dosimetry (TLD) powder and then back to a liquid for recovery of the TLD powder without adversely effecting the TLD powder. The gelatine mixture provided the closest match to the data from Reference Man tissue. The gelatine mixture was put through a series of test to determine it`s usefulness as a reliable tissue substitute. The TLD powder was cast in the gelatine mixture and recovered to determine if the TLD powder was adversely effected. The distribution of the TLD powder after being cast into the gelatin mixture was tested in insure an even was maintained.

  8. A study of a tissue equivalent gelatine based tissue substitute

    SciTech Connect

    Spence, J.L.

    1992-11-01

    A study of several tissue substitutes for use as volumetric dosimeters was performed. The tissue substitutes studied included tissue substitutes from previous studies and from ICRU 44. The substitutes were evaluated for an overall match to Reference Man which was used as a basis for this study. The evaluation was based on the electron stopping power, the mass attenuation coefficient, the electron density, and the specific gravity. The tissue substitute chosen also had to be capable of changing from a liquid into a solid form to maintain an even distribution of thermoluminesent dosimetry (TLD) powder and then back to a liquid for recovery of the TLD powder without adversely effecting the TLD powder. The gelatine mixture provided the closest match to the data from Reference Man tissue. The gelatine mixture was put through a series of test to determine it's usefulness as a reliable tissue substitute. The TLD powder was cast in the gelatine mixture and recovered to determine if the TLD powder was adversely effected. The distribution of the TLD powder after being cast into the gelatin mixture was tested in insure an even was maintained.

  9. Performance of low pressure tissue equivalent chambers and a new method for parameterizing the dose equivalent

    SciTech Connect

    Eisen, Y.; Vasilik, D.G.; Brake, R.J.; Erkkila, B.H.; Littlejohn, G.J.

    1986-09-01

    The performance of spherical tissue equivalent chambers with equivalent diameters between 0.5 and 2..mu.. was tested experimentally using monoenergetic and polyenergetic neutron sources in the energy region of 10 keV to 14.5 MeV. Theoretical calculations were performed in order to obtain a simple algorithm for deriving the dose equivalent from the measured data. The algorithm relates the number of recoil particles to the dose equivalent, rather than having a one-to-one correspondence between the lineal energy and the linear energy transfer of the recoil particles. The calculations took into account neutron interactions with hydrogen atoms in the chamber wall as well as in the gas, and also the finite energy resolution determined by both the detector and the electronic system. Qualitatively, the calculations well dscribe the experimental results. The algorithm that was developed determines the neutron dose equivalent, from the data of the 0.5..mu.. chamber, to better than +-20% over the energy range of 30 keV to 14.5 MeV. The same algorithm also determines the dose equivalent from the data of the 2..mu.. chamber to better than +-20% over the energy of 70 keV to 14.5 MeV. The efficiency of the chambers is low and has an average value of 330 counts per mrem, or equivalently about 0.2 c/s per mrem/h. This efficiency enables the measurement of dose equivalent rates only above 100 mrem/h for an integration period of 3 seconds. However, integrated dose equivalents can be mesured as low as 0.1 mrem.

  10. Neutron kerma factors and water equivalence of some tissue substitutes.

    PubMed

    Singh, V P; Badiger, N M; Vega-Carrillo, Hector Rene

    2015-09-01

    The Kerma factors and Kerma relative to the air and water of 24 compounds that are used as tissue substitutes were calculated for neutron energies ranging from 2.53×10(-8) to 29 MeV. The Kerma ratios of the tissue substitutes relative to air and water were calculated. The water equivalence of the selected tissue substitutes was observed above neutron energies of 100 eV. The Kerma ratio relative to the air for poly-vinylidene fluoride and Teflon were nearest to unity at very low energy (up to 1 eV) and above 63 eV, respectively. It was found that the natural rubber was a water-equivalent tissue substitute compound. The results of the Kerma factors in our investigation show good agreement with those published in ICRU-44. We found that at higher neutron energies, the Kerma factors and Kerma ratios of the selected tissue substitute compounds were approximately the same, but though the differences were large for energies below 100 eV. PMID:26073270

  11. A computational study into the use of polyacrylamide gel and A-150 plastic as brain tissue substitutes for boron neutron capture therapy

    NASA Astrophysics Data System (ADS)

    Wojnecki, C.; Green, S.

    2001-05-01

    A precise evaluation of the dosimetric performance of epithermal neutron beams designed for boron neutron capture theory of brain tumours requires the use of a phantom material that closely matches brain tissue. The aim of this study was to investigate how well polyacrylamide gel (or PAG) and A-150 plastic performed as substitutes for brain tissue compared with standard phantom materials such as water and polymethyl-methacrylate (or PMMA). Thermal neutron fluence, photon dose and epithermal neutron dose distributions were calculated for the epithermal neutron beam available at the University of Birmingham. The results presented in this paper show that the PAG provides a good simulation of radiation transport in the brain with differences from the real brain of + 9.4%, -10.8% and + 5.1% at a depth of 50 mm for thermal neutron fluence, gamma dose and epithermal neutron dose distributions respectively. The polyacrylamide gel presented is therefore a promising substitute for brain tissue that can, as a dosimeter, provide a three-dimensional map of the absorbed dose delivered by the epithermal neutron beam. However, this study does not investigate the agreement between doses derived from magnetic resonance and physical doses for such gels. A-150 plastic was shown to be a better substitute for brain tissue than PMMA, with differences from brain of -1.9%, -12.4% and -13.2% at a depth of 50 mm for thermal neutron fluence, gamma dose and epithermal neutron dose distributions respectively, against + 21.1%, -16.2% and + 19.2% for PMMA. A-150 plastic should therefore be the material of choice for solid phantoms.

  12. Kinetic parameters of some tissue equivalent thermoluminescence materials

    NASA Astrophysics Data System (ADS)

    Kitis, G.; Furetta, C.; Prokic, M.; Prokic, V.

    2000-06-01

    The paper reports a study on the kinetic parameters of some thermoluminescent tissue equivalent materials recently prepared in Vinca Institute: Li2B4O7:Mn,Si, Li2B4O7:Cu, Li2B4O7:Cu,In and MgB4O7:Dy,Na. The kinetics parameters have been determined using several methods. The temperature lag effect, which could produce large errors in the parameters' determination when they are determined using high heating rates, has also been taken into consideration.

  13. Detection of ultraviolet radiation using tissue equivalent radiochromic gel materials

    NASA Astrophysics Data System (ADS)

    Bero, M. A.; Abukassem, I.

    2009-05-01

    Ferrous Xylenol-orange Gelatin gel (FXG) is known to be sensitive to ionising radiation such as γ and X-rays. The effect of ionising radiation is to produce an increase in the absorption over a wide region of the visible spectrum, which is proportional to the absorbed dose. This study demonstrates that FXG gel is sensitive to ultraviolet radiation and therefore it could functions as UV detector. Short exposure to UV radiation produces linear increase in absorption measured at 550nm, however high doses of UV cause the ion indicator colour to fad away in a manner proportional to the incident UV energy. Light absorbance increase at the rate of 1.1% per minute of irradiation was monitored. The exposure level at which the detector has linear response is comparable to the natural summer UV radiation. Evaluating the UV ability to pass through tissue equivalent gel materials shows that most of the UV gets absorbed in the first 5mm of the gel materials, which demonstrate the damaging effects of this radiation type on human skin and eyes. It was concluded that FXG gel dosimeter has the potential to offer a simple, passive ultraviolet radiation detector with sensitivity suitable to measure and visualises the natural sunlight UV exposure directly by watching the materials colour changes.

  14. Replacement tissue-equivalent proportional counter for the International Space Station.

    PubMed

    Perez-Nunez, D; Braby, L A

    2011-02-01

    The tissue-equivalent proportional counter (TEPC)-based dosemeters used on the International Space Station have exceeded their planned useful lives, and are scheduled to be replaced with the new units taking advantage of improved technology. The original TEPC detectors used cylindrical geometry with field tubes to achieve good energy resolution and minimum sensitivity to noise created by vibration. The inside diameter of these detectors is 5.1 cm. The new detectors developed for this application produce the resolution and vibration resistance of the cylindrical detector with the isotropic response and compact size of a spherical detector. The cathode structure consists of conductive tissue-equivalent plastic A-150 layers separated by thin polyethylene layers perpendicular to the anode. Each conductive layer is held at the electrical potential needed to produce uniform electric field strength along the anode wire, and thus the same gas gain for electrons produced in different portions of the spherical volume. The new design contains the whole preamplifier inside the vacuum chamber to reduce electronic noise. Also the vacuum chamber has a novel design with a 0.020-inch-thick aluminium wall to allow a total wall thickness of 0.5 g cm(-2), which is typical of the shielding provided by a space suit. This feature will allow measuring the dose on the astronauts' skin due to low-energy electrons and protons produced during solar events. The vacuum chamber has a new bayonet clamping system that reduces the total detector weight to less than half that of the old TEPC. PMID:21115447

  15. Microwave imaging for tissue assessment: initial evaluation in multitarget tissue-equivalent phantoms.

    PubMed

    Meaney, P M; Paulsen, K D; Hartov, A; Crane, R K

    1996-09-01

    A prototype microwave imaging system is evaluated for its ability to recover two-dimensional (2-D) electrical property distributions under transverse magnetic (TM) illumination using multitarget tissue equivalent phantoms. Experiments conducted in a surrounding lossy saline tank demonstrate that simultaneous recovery of both the real and imaginary components of the electrical property distribution is possible using absolute imaging procedures over a frequency range of 300-700 MHz. Further, image reconstructions of embedded tissue-equivalent targets are found to be quantitative not only with respect to geometrical factors such as object size and location but also electrical composition. Quantitative assessments based on full-width half-height criteria reveal that errors in diameter estimates of reconstructed targets are less than 10 mm in all cases, whereas, positioning errors are less than 1 mm in single object experiments but degrade to 4-10 mm when multiple targets are present. Recovery of actual electrical properties is found to be frequency dependent for the real and imaginary components with background values being typically within 10-20% of their correct size and embedded object having similar accuracies as a percentage of the electrical contrast, although errors as high as 50% can occur. The quantitative evaluation of imaging performance has revealed potential advantages in a two-tiered receiver antenna configuration whose measured field values are more sensitive to target region changes than the typical tomographic type of approach which uses reception sites around the full target region perimeter. This measurement strategy has important implications for both the image reconstruction algorithm where there is a premium on minimizing problem size without sacrificing image quality and the hardware system design which seeks to economize on the amount of measured data required for quantitative image reconstruction while maximizing its sensitivity to target

  16. Neutron spectra and dose equivalents calculated in tissue for high-energy radiation therapy

    SciTech Connect

    Kry, Stephen F.; Howell, Rebecca M.; Salehpour, Mohammad; Followill, David S.

    2009-04-15

    Neutrons are by-products of high-energy radiation therapy and a source of dose to normal tissues. Thus, the presence of neutrons increases a patient's risk of radiation-induced secondary cancer. Although neutrons have been thoroughly studied in air, little research has been focused on neutrons at depths in the patient where radiosensitive structures may exist, resulting in wide variations in neutron dose equivalents between studies. In this study, we characterized properties of neutrons produced during high-energy radiation therapy as a function of their depth in tissue and for different field sizes and different source-to-surface distances (SSD). We used a previously developed Monte Carlo model of an accelerator operated at 18 MV to calculate the neutron fluences, energy spectra, quality factors, and dose equivalents in air and in tissue at depths ranging from 0.1 to 25 cm. In conjunction with the sharply decreasing dose equivalent with increased depth in tissue, the authors found that the neutron energy spectrum changed drastically as a function of depth in tissue. The neutron fluence decreased gradually as the depth increased, while the average neutron energy decreased sharply with increasing depth until a depth of approximately 7.5 cm in tissue, after which it remained nearly constant. There was minimal variation in the quality factor as a function of depth. At a given depth in tissue, the neutron dose equivalent increased slightly with increasing field size and decreasing SSD; however, the percentage depth-dose equivalent curve remained constant outside the primary photon field. Because the neutron dose equivalent, fluence, and energy spectrum changed substantially with depth in tissue, we concluded that when the neutron dose equivalent is being determined at a depth within a patient, the spectrum and quality factor used should be appropriate for depth rather than for in-air conditions. Alternately, an appropriate percent depth-dose equivalent curve should be

  17. Measurement of lineal-energy distributions for neutrons of 8 keV to 65 MeV by using a tissue-equivalent proportional counter.

    PubMed

    Nunomiya, T; Kim, E; Kurosaw, T; Taniguchi, S; Nakamura, T; Nakane, Y; Sakamoto, Y; Tanaka, S

    2002-01-01

    The lineal-energy spectra for monoenergetic and quasi-monoenergetic neutrons of 8 keV to 65 MeV were obtained using a tissue-equivalent proportional counter (TEPC). The frequency-mean lineal energy, the dose-average lineal energy and mean quality factor were estimated from the measured data. The neutron absorbed doses obtained with this TEPC were compared with the kerma coefticient for A-150 plastic defined by ICRP 26 and the mean quality factors were compared with the data of ICRP 74. respectively. These comparisons indicated good agreement between them. PMID:12212902

  18. Polyurethane as a base for a family of tissue equivalent materials

    SciTech Connect

    Griffith, R.V.

    1980-01-01

    Polyurethane was used as a base material for a wide variety of tissue simulating applications. The technique in fabrication is similar to that of epoxy, however, the end products are generally more flexible for use in applications where flexibility is valuable. The material can be fabricated with relatively small laboratory equipment. The use of polyurethane provides the dosimetrist with the capability of making specific, accurate, on-the-spot tissue equivalent formulations to meet situations which require immediate calibration and response.

  19. TACI: a code for interactive analysis of neutron data produced by a tissue equivalent proportional counter

    SciTech Connect

    Cummings, F.M.

    1984-06-01

    The TEPC analysis code (TACI) is a computer program designed to analyze pulse height data generated by a tissue equivalent proportional counter (TEPC). It is written in HP BASIC and is for use on an HP-87XM personal computer. The theory of TEPC analysis upon which this code is based is summarized.

  20. Bio-fabrication and physiological self-release of tissue equivalents using smart peptide amphiphile templates.

    PubMed

    Gouveia, Ricardo M; Hamley, Ian W; Connon, Che J

    2015-10-01

    In this study we applied a smart biomaterial formed from a self-assembling, multi-functional synthetic peptide amphiphile (PA) to coat substrates with various surface chemistries. The combination of PA coating and alignment-inducing functionalised substrates provided a template to instruct human corneal stromal fibroblasts to adhere, become aligned and then bio-fabricate a highly-ordered, multi-layered, three-dimensional tissue by depositing an aligned, native-like extracellular matrix. The newly-formed corneal tissue equivalent was subsequently able to eliminate the adhesive properties of the template and govern its own complete release via the action of endogenous proteases. Tissues recovered through this method were structurally stable, easily handled, and carrier-free. Furthermore, topographical and mechanical analysis by atomic force microscopy showed that tissue equivalents formed on the alignment-inducing PA template had highly-ordered, compact collagen deposition, with a two-fold higher elastic modulus compared to the less compact tissues produced on the non-alignment template, the PA-coated glass. We suggest that this technology represents a new paradigm in tissue engineering and regenerative medicine, whereby all processes for the bio-fabrication and subsequent self-release of natural, bio-prosthetic human tissues depend solely on simple template-tissue feedback interactions. PMID:26411438

  1. Effective atomic numbers, water and tissue equivalence properties of human tissues, tissue equivalents and dosimetric materials for total electron interaction in the energy region 10 keV-1 GeV.

    PubMed

    Kurudirek, Murat

    2014-12-01

    Effective atomic numbers (Zeff) of 107 different materials of dosimetric interest have been calculated for total electron interactions in the wide energy region 10keV-1GeV. The stopping cross sections of elements and dosimetric materials were used to calculate Zeff of the materials. Differences (%) in Zeff relative to water have been calculated in the entire energy region to evaluate the water equivalency of the used materials. Moreover, the tissue equivalent materials have been compared with the tissues and dosimetric materials in terms of Zeff to reveal their ability to use as tissue substitutes. Possible conclusions were drawn based on the variation of Zeff through the entire energy region and water and tissue equivalency comparisons in terms of Zeff. PMID:25061891

  2. Tissue Equivalent Phantom Design for Characterization of a Coherent Scatter X-ray Imaging System

    NASA Astrophysics Data System (ADS)

    Albanese, Kathryn Elizabeth

    Scatter in medical imaging is typically cast off as image-related noise that detracts from meaningful diagnosis. It is therefore typically rejected or removed from medical images. However, it has been found that every material, including cancerous tissue, has a unique X-ray coherent scatter signature that can be used to identify the material or tissue. Such scatter-based tissue-identification provides the advantage of locating and identifying particular materials over conventional anatomical imaging through X-ray radiography. A coded aperture X-ray coherent scatter spectral imaging system has been developed in our group to classify different tissue types based on their unique scatter signatures. Previous experiments using our prototype have demonstrated that the depth-resolved coherent scatter spectral imaging system (CACSSI) can discriminate healthy and cancerous tissue present in the path of a non-destructive x-ray beam. A key to the successful optimization of CACSSI as a clinical imaging method is to obtain anatomically accurate phantoms of the human body. This thesis describes the development and fabrication of 3D printed anatomical scatter phantoms of the breast and lung. The purpose of this work is to accurately model different breast geometries using a tissue equivalent phantom, and to classify these tissues in a coherent x-ray scatter imaging system. Tissue-equivalent anatomical phantoms were designed to assess the capability of the CACSSI system to classify different types of breast tissue (adipose, fibroglandular, malignant). These phantoms were 3D printed based on DICOM data obtained from CT scans of prone breasts. The phantoms were tested through comparison of measured scatter signatures with those of adipose and fibroglandular tissue from literature. Tumors in the phantom were modeled using a variety of biological tissue including actual surgically excised benign and malignant tissue specimens. Lung based phantoms have also been printed for future

  3. Concise Review: Comparison of Culture Membranes Used for Tissue Engineered Conjunctival Epithelial Equivalents

    PubMed Central

    Eidet, Jon Roger; Dartt, Darlene A.; Utheim, Tor Paaske

    2015-01-01

    The conjunctival epithelium plays an important role in ensuring the optical clarity of the cornea by providing lubrication to maintain a smooth, refractive surface, by producing mucins critical for tear film stability and by protecting against mechanical stress and infectious agents. A large number of disorders can lead to scarring of the conjunctiva through chronic conjunctival inflammation. For controlling complications of conjunctival scarring, surgery can be considered. Surgical treatment of symblepharon includes removal of the scar tissue to reestablish the deep fornix. The surgical defect is then covered by the application of a tissue substitute. One obvious limiting factor when using autografts is the size of the defect to be covered, as the amount of healthy conjunctiva is scarce. These limitations have led scientists to develop tissue engineered conjunctival equivalents. A tissue engineered conjunctival epithelial equivalent needs to be easily manipulated surgically, not cause an inflammatory reaction and be biocompatible. This review summarizes the various substrates and membranes that have been used to culture conjunctival epithelial cells during the last three decades. Future avenues for developing tissue engineered conjunctiva are discussed. PMID:26690486

  4. Accurate determination of the complex refractive index of solid tissue-equivalent phantom

    NASA Astrophysics Data System (ADS)

    Wang, Jin; Ye, Qing; Deng, Zhichao; Zhou, Wenyuan; Zhang, Chunping; Tian, Jianguo

    2012-06-01

    Tissue-equivalent phantom is becoming widespread as a substitute in the biological field to verify optical theories, test measuring systems and study the tissue performances for varying boundary conditions, sample size and shape at a quantitative level. Compared with phantoms made with Intralipid solution, ink and other liquid substances, phantom in solid state is stable over time, reproducible, easy to handle and has been testified to be a suitable optical simulator in the visible and near-infrared region. We present accurate determination of the complex refractive index (RI) of a solid tissueequivalent phantom using extended derivative total reflection method (EDTRM). Scattering phantoms in solid state were measured for p-polarized and s-polarized incident light respectively. The reflectance curves of the sample as a function of incident angle were recorded. The real part of RI is directly determined by derivative of the reflectance curve, and the imaginary part is obtained from nonlinear fitting based on the Fresnel equation and Nelder-Mead simplex method. The EDTRM method is applicable for RI measurement of high scattering media such as biotissue, solid tissue-equivalent phantom and bulk material. The obtained RI information can be used in the study of tissue optics and biomedical field.

  5. Positron range in tissue-equivalent materials: experimental microPET studies

    NASA Astrophysics Data System (ADS)

    Alva-Sánchez, H.; Quintana-Bautista, C.; Martínez-Dávalos, A.; Ávila-Rodríguez, M. A.; Rodríguez-Villafuerte, M.

    2016-09-01

    In this work an experimental investigation was carried out to study the effect that positron range has over positron emission tomography (PET) scans through measurements of the line spread function (LSF) in tissue-equivalent materials. Line-sources consisted of thin capillary tubes filled with 18F, 13N or 68Ga water-solution inserted along the axis of symmetry of cylindrical phantoms constructed with the tissue-equivalent materials: lung (inhale and exhale), adipose tissue, solid water, trabecular and cortical bone. PET scans were performed with a commercial small-animal PET scanner and image reconstruction was carried out with filtered-backprojection. Line-source distributions were analyzed using radial profiles taken on axial slices from which the spatial resolution was determined through the full-width at half-maximum, tenth-maximum, twentieth-maximum and fiftieth-maximum. A double-Gaussian model of the LSFs was used to fit experimental data which can be incorporated into iterative reconstruction methods. In addition, the maximum activity concentration in the line-sources was determined from reconstructed images and compared to the known values for each case. The experimental data indicates that positron range in different materials has a strong effect on both spatial resolution and activity concentration quantification in PET scans. Consequently, extra care should be taken when computing standard-uptake values in PET scans, in particular when the radiopharmaceutical is taken up by different tissues in the body, and more even so with high-energy positron emitters.

  6. Tissue-equivalent torso phantom for calibration of transuranic-nuclide counting facilities

    SciTech Connect

    Griffith, R.V.; Anderson, A.L.; Dean, P.N.; Fisher, J.C.; Sundbeck, C.W.

    1986-01-16

    Several tissue-equivalent human-torso phantoms have been constructed for the calibration of counting systems used for in-vivo measurement of transuranic radionuclides. The phantoms contain a simulated human rib cage (in some cases, real bone) and removable model organs, and they include tissue-equivalent chest plates that can be placed over the torso to simulate people with a wide range of statures. The organs included are the lungs, liver, and tracheobronchial lymph nodes. Polyurethane with varying concentrations of added calcium was used to simulate the linear photon-attenuation properties of various human tissues, including lean muscle, adipose-muscle mixtures, cartilage, and bone. Foamed polyurethane was used to simulate lung tissue. Organs have been loaded with highly pure /sup 238/Pu, /sup 239/Pu, /sup 241/Am, and other radionuclides of interest. The validity of the phantom as a calibration standard has been checked in separate intercomparison studies using human subjects whose lungs contained a plutonium simulant. The resulting phantom calibration factors generally compared to within +-20% of the average calibration factors obtained for the human subjects.

  7. SU-E-T-329: Tissue-Equivalent Phantom Materials for Neutron Dosimetry in Proton Therapy

    SciTech Connect

    Halg, R; Lomax, A; Clarke, S; Wieger, B; Pryser, E; Arghal, R; Pozzi, S; Bashkirov, V; Schulte, R; Schneider, U

    2014-06-01

    Purpose: To characterize tissue equivalence of phantom materials in terms of secondary neutron production and dose deposition from neutrons produced in radiation therapy phantom materials in the context of proton therapy using Monte Carlo simulations and measurements. Methods: In order to study the influence of material choice on neutron production in therapeutic proton beams, Monte Carlo simulations using the Geant4 and MCNPX-PoliMi transport codes were performed to generate the neutron fields produced by protons of 155 and 200 MeV. A simple irradiation geometry was used to investigate the effect of different materials. The proton beams were stopped in slab phantoms to study the production of secondary neutrons. The investigated materials were water, Lucite, and tissue-equivalent phantom materials (CIRS Inc., Norfolk, VA). Neutron energy spectra and absorbed dose by neutrons and their secondary particles were scored. In addition, simulations were performed for reference tissues (ICRP/ICRU) to assess tissue equivalence with respect to neutron generation and transport. In order to benchmark the simulation results, measurements were performed with a system developed at the University of Michigan; organic liquid scintillators were used to detect the neutron emissions from the irradiation of tissue-equivalent materials. Additionally, the MPPost code was used to calculate the scintillator response from the MCNPX-PoliMi output. Results: The simulated energy spectra and depth dose curves of the neutrons produced in different phantom materials showed similar shape. The differences of spectra and fluences between all studied materials and reference tissues were well within the achievable precision of neutron dosimetry. The shape of the simulated detector response of the liquid scintillators agreed well with measurements on the proton beamline. Conclusion: Based on Geant4 and MCNPX-PoliMi simulations, the investigated materials appear to be suitable to study the production

  8. Nuclear reaction measurements on tissue-equivalent materials and GEANT4 Monte Carlo simulations for hadrontherapy

    NASA Astrophysics Data System (ADS)

    De Napoli, M.; Romano, F.; D'Urso, D.; Licciardello, T.; Agodi, C.; Candiano, G.; Cappuzzello, F.; Cirrone, G. A. P.; Cuttone, G.; Musumarra, A.; Pandola, L.; Scuderi, V.

    2014-12-01

    When a carbon beam interacts with human tissues, many secondary fragments are produced into the tumor region and the surrounding healthy tissues. Therefore, in hadrontherapy precise dose calculations require Monte Carlo tools equipped with complex nuclear reaction models. To get realistic predictions, however, simulation codes must be validated against experimental results; the wider the dataset is, the more the models are finely tuned. Since no fragmentation data for tissue-equivalent materials at Fermi energies are available in literature, we measured secondary fragments produced by the interaction of a 55.6 MeV u-1 12C beam with thick muscle and cortical bone targets. Three reaction models used by the Geant4 Monte Carlo code, the Binary Light Ions Cascade, the Quantum Molecular Dynamic and the Liege Intranuclear Cascade, have been benchmarked against the collected data. In this work we present the experimental results and we discuss the predictive power of the above mentioned models.

  9. Simulated Response of a Tissue-equivalent Proportional Counter on the Surface of Mars.

    PubMed

    Northum, Jeremy D; Guetersloh, Stephen B; Braby, Leslie A; Ford, John R

    2015-10-01

    Uncertainties persist regarding the assessment of the carcinogenic risk associated with galactic cosmic ray (GCR) exposure during a mission to Mars. The GCR spectrum peaks in the range of 300(-1) MeV n to 700 MeV n(-1) and is comprised of elemental ions from H to Ni. While Fe ions represent only 0.03% of the GCR spectrum in terms of particle abundance, they are responsible for nearly 30% of the dose equivalent in free space. Because of this, radiation biology studies focusing on understanding the biological effects of GCR exposure generally use Fe ions. Acting as a thin shield, the Martian atmosphere alters the GCR spectrum in a manner that significantly reduces the importance of Fe ions. Additionally, albedo particles emanating from the regolith complicate the radiation environment. The present study uses the Monte Carlo code FLUKA to simulate the response of a tissue-equivalent proportional counter on the surface of Mars to produce dosimetry quantities and microdosimetry distributions. The dose equivalent rate on the surface of Mars was found to be 0.18 Sv y(-1) with an average quality factor of 2.9 and a dose mean lineal energy of 18.4 keV μm(-1). Additionally, albedo neutrons were found to account for 25% of the dose equivalent. It is anticipated that these data will provide relevant starting points for use in future risk assessment and mission planning studies. PMID:26313586

  10. Sex-specific tissue weighting factors for effective dose equivalent calculations

    SciTech Connect

    Xu, X.G.; Reece, W.D.

    1996-01-01

    The effective dose equivalent was defined in the International Commission on Radiological Protection Publication 26 in 1977 and later adopted by the U.S. Nuclear REgulatory Commission. To calculate organ doses and effective dose equivalent for external exposures using Monte Carlo simulations, sex-specific anthropomorphic phantoms and sex-specific weighting factors are always employed. This paper presents detailed mathematical derivation of a set of sex-specific tissue weighting factors and the conditions which the weighting factors must satisfy. Results of effective dose equivalent calculations using female and male phantoms exposed to monoenergetic photon beams of 0.08, 0.3, and 1.0 MeV are provided and compared with results published by other authors using different sex-specific weighting factors and phantoms. The results indicate that females always receive higher effective dose equivalent than males for the photon energies and geometries considered and that some published data may be wrong due to mistakes in deriving the sex-specific weighting factors. 17 refs., 2 figs., 2 tabs.

  11. Improved MAGIC gel for higher sensitivity and elemental tissue equivalent 3D dosimetry

    SciTech Connect

    Zhu Xuping; Reese, Timothy G.; Crowley, Elizabeth M.; El Fakhri, Georges

    2010-01-15

    Purpose: Polymer-based gel dosimeter (MAGIC type) is a preferable phantom material for PET range verification of proton beam therapy. However, improvement in elemental tissue equivalency (specifically O/C ratio) is very desirable to ensure realistic time-activity measurements. Methods: Glucose and urea was added to the original MAGIC formulation to adjust the O/C ratio. The dose responses of the new formulations were tested with MRI transverse relaxation rate (R2) measurements. Results: The new ingredients improved not only the elemental composition but also the sensitivity of the MAGIC gel. The O/C ratios of our new gels agree with that of soft tissue within 1%. The slopes of dose response curves were 1.6-2.7 times larger with glucose. The melting point also increased by 5 deg. C. Further addition of urea resulted in a similar slope but with an increased intercept and a decreased melting point. Conclusions: Our improved MAGIC gel formulations have higher sensitivity and better elemental tissue equivalency for 3D dosimetry applications involving nuclear reactions.

  12. Improved MAGIC gel for higher sensitivity and elemental tissue equivalent 3D dosimetry

    PubMed Central

    Zhu, Xuping; Reese, Timothy G.; Crowley, Elizabeth M.; El Fakhri, Georges

    2010-01-01

    Purpose: Polymer-based gel dosimeter (MAGIC type) is a preferable phantom material for PET range verification of proton beam therapy. However, improvement in elemental tissue equivalency (specifically O∕C ratio) is very desirable to ensure realistic time-activity measurements. Methods: Glucose and urea was added to the original MAGIC formulation to adjust the O∕C ratio. The dose responses of the new formulations were tested with MRI transverse relaxation rate (R2) measurements. Results: The new ingredients improved not only the elemental composition but also the sensitivity of the MAGIC gel. The O∕C ratios of our new gels agree with that of soft tissue within 1%. The slopes of dose response curves were 1.6–2.7 times larger with glucose. The melting point also increased by 5 °C. Further addition of urea resulted in a similar slope but with an increased intercept and a decreased melting point. Conclusions: Our improved MAGIC gel formulations have higher sensitivity and better elemental tissue equivalency for 3D dosimetry applications involving nuclear reactions. PMID:20175480

  13. Analysis of biological tissues in infant chest for the development of an equivalent radiographic phantom

    SciTech Connect

    Pina, D. R.; Souza, Rafael T. F.; Duarte, Sergio B.; Alvarez, Matheus; Miranda, Jose R. A.

    2012-03-15

    Purpose: The main purpose of the present study was to determine the amounts of different tissues in the chest of the newborn patient (age {<=}1 year), with the aim of developing a homogeneous phantom chest equivalent. This type of phantom is indispensable in the development of optimization procedures for radiographic techniques, including dosimetric control, which is a crucial aspect of pediatric radiology. The authors present a systematic set of procedures, including a computational algorithm, to estimate the amounts of tissues and thicknesses of the corresponding simulator material plates used to construct the phantom. Methods: The Gaussian fit of computed tomographic (CT) analysis was applied to classify and quantify different biological tissues. The methodology is summarized with a computational algorithm, which was used to quantify tissues through automated CT analysis. The thicknesses of the equivalent homogeneous simulator material plates were determined to construct the phantom. Results: A total of 180 retrospective CT examinations with anterior-posterior diameter values ranging 8.5-13.0 cm were examined. The amounts of different tissues were evaluated. The results provided elements to construct a phantom to simulate the infant chest in the posterior-anterior or anterior-posterior (PA/AP) view. Conclusions: To our knowledge, this report represents the first demonstration of an infant chest phantom dedicated to the radiology of children younger than one year. This phantom is a key element in the development of clinical charts for optimizing radiographic technique in pediatric patients. Optimization procedures for nonstandard patients were reported previously [Pina et al., Phys. Med. Biol. 49, N215-N226 (2004) and Pina et al., Appl. Radiat. Isot. 67, 61-69 (2009)]. The constructed phantom represents a starting point to obtain radiologic protocols for the infant patient.

  14. Use of tissue equivalent proportional counters to characterize radiation quality on the space shuttle

    SciTech Connect

    Braby, L.A.; Conroy, T.J.; Elegy, D.C.; Brackenbush, L.W.

    1992-04-01

    Tissue equivalent proportional counters (TEPC) are essentially cavity ionization chambers operating at low pressure and with gas gain. A small, battery powered, TEPC spectrometer, which records lineal energy spectra at one minute intervals, has been used on several space shuttle missions. The data it has collected clearly show the South Atlantic anomaly and indicate a mean quality factor somewhat higher than expected. An improved type of instrument has been developed with sufficient memory to record spectra at 10 second intervals, and with increased resolution for low LET events. This type of instrument will be used on most future space shuttle flights and in some international experiments.

  15. Positron range in tissue-equivalent materials: experimental microPET studies.

    PubMed

    Alva-Sánchez, H; Quintana-Bautista, C; Martínez-Dávalos, A; Ávila-Rodríguez, M A; Rodríguez-Villafuerte, M

    2016-09-01

    In this work an experimental investigation was carried out to study the effect that positron range has over positron emission tomography (PET) scans through measurements of the line spread function (LSF) in tissue-equivalent materials. Line-sources consisted of thin capillary tubes filled with (18)F, (13)N or (68)Ga water-solution inserted along the axis of symmetry of cylindrical phantoms constructed with the tissue-equivalent materials: lung (inhale and exhale), adipose tissue, solid water, trabecular and cortical bone. PET scans were performed with a commercial small-animal PET scanner and image reconstruction was carried out with filtered-backprojection. Line-source distributions were analyzed using radial profiles taken on axial slices from which the spatial resolution was determined through the full-width at half-maximum, tenth-maximum, twentieth-maximum and fiftieth-maximum. A double-Gaussian model of the LSFs was used to fit experimental data which can be incorporated into iterative reconstruction methods. In addition, the maximum activity concentration in the line-sources was determined from reconstructed images and compared to the known values for each case. The experimental data indicates that positron range in different materials has a strong effect on both spatial resolution and activity concentration quantification in PET scans. Consequently, extra care should be taken when computing standard-uptake values in PET scans, in particular when the radiopharmaceutical is taken up by different tissues in the body, and more even so with high-energy positron emitters. PMID:27494279

  16. Verification of intensity modulated radiation therapy beams using a tissue equivalent plastic scintillator dosimetry system

    NASA Astrophysics Data System (ADS)

    Petric, Martin Peter

    This thesis describes the development and implementation of a novel method for the dosimetric verification of intensity modulated radiation therapy (IMRT) fields with several advantages over current techniques. Through the use of a tissue equivalent plastic scintillator sheet viewed by a charge-coupled device (CCD) camera, this method provides a truly tissue equivalent dosimetry system capable of efficiently and accurately performing field-by-field verification of IMRT plans. This work was motivated by an initial study comparing two IMRT treatment planning systems. The clinical functionality of BrainLAB's BrainSCAN and Varian's Helios IMRT treatment planning systems were compared in terms of implementation and commissioning, dose optimization, and plan assessment. Implementation and commissioning revealed differences in the beam data required to characterize the beam prior to use with the BrainSCAN system requiring higher resolution data compared to Helios. This difference was found to impact on the ability of the systems to accurately calculate dose for highly modulated fields, with BrainSCAN being more successful than Helios. The dose optimization and plan assessment comparisons revealed that while both systems use considerably different optimization algorithms and user-control interfaces, they are both capable of producing substantially equivalent dose plans. The extensive use of dosimetric verification techniques in the IMRT treatment planning comparison study motivated the development and implementation of a novel IMRT dosimetric verification system. The system consists of a water-filled phantom with a tissue equivalent plastic scintillator sheet built into the top surface. Scintillation light is reflected by a plastic mirror within the phantom towards a viewing window where it is captured using a CCD camera. Optical photon spread is removed using a micro-louvre optical collimator and by deconvolving a glare kernel from the raw images. Characterization of this

  17. Optimization of the electric field distribution in a large volume tissue-equivalent proportional counter.

    PubMed

    Verma, P K; Waker, A J

    1992-10-01

    Large volume tissue-equivalent proportional counters are of interest in radiation protection metrology, as the sensitivity in terms of counts per unit absorbed dose in these devices increases as the square of the counter diameter. Conventional solutions to the problem of maintaining a uniform electric field within a counter result in sensitive volume to total volume ratios which are unacceptably low when counter dimensions of the order of 15 cm diameter are considered and when overall compactness is an important design criterion. This work describes the design and optimization of an arrangement of field discs set at different potentials which enable sensitive volume to total volume ratios to approach unity. The method has been used to construct a 12.7 cm diameter right-cylindrical tissue-equivalent proportional counter in which the sensitive volume accounts for over 95% of the total device volume and the gas gain uniformity is maintained to within 3% along the entire length of the anode wire. PMID:1438550

  18. The response of tissue-equivalent proportional counters to heavy ions.

    PubMed

    Nikjoo, Hooshang; Khvostunov, Igor K; Cucinotta, Francis A

    2002-04-01

    The paper presents a theoretical model for the response of a tissue-equivalent proportional counter (TEPC) irradiated with charged particles. Heavy ions and iron ions in particular constitute a significant part of radiation in space. TEPCs are used for all space shuttle and International Space Station (ISS) missions to estimate the dose and radiation quality (in terms of lineal energy) inside spacecraft. The response of the tissue-equivalent proportional counters shows distortions at the wall/cavity interface. In this paper, we present microdosimetric investigation using Monte Carlo track structure calculations to simulate the response of a TEPC to charged particles of various LET (1 MeV protons, 2.4 MeV alpha particles, 46 MeV/nucleon 20Ne, 55 MeV/nucleon 20Ne, 45 MeV/nucleon 40Ar, and 1.05 GeV/nucleon 56Fe). Data are presented for energy lost and energy absorbed in the counter cavity and wall. The model calculations are in good agreement with the results of Rademacher et al. (Radiat. Res. 149, 387-389, 1998), including the study of the interface between the wall and the sensitive region of the counter. It is shown that the anomalous response observed at large event sizes in the experiment is due to an enhanced entry of secondary electrons from the wall into the gas cavity. PMID:11893246

  19. Miniature Tissue Equivalent Proportional Counter dosimeter for active personal radiation monitoring of astronauts

    NASA Astrophysics Data System (ADS)

    Watson Huber, Aubrey

    The accurate measurement of spaceflight crew radiation exposure is of utmost importance. If onboard instrumentation shows that the pre-determined limit for radiation exposure has been met or exceeded during a mission, that mission can be greatly affected by the implementation of precautionary measures, or, in more extreme cases, the crew's health being negatively affected. Large active regional monitors determine real-time radiation risks of the crew during spaceflight, while small passive personal badges detect individual astronaut total exposure levels upon their return to Earth. At present, there are no personal active radiation dosimeters that can assess the continuous radiation risk to individual astronauts during spaceflight. Personal active radiation devices would be ideal for current operations in low-Earth orbit (LEO), as well as upcoming extravehicular activities on the Moon, Mars, or other planetary bodies. This project focused on the miniaturization of the Tissue Equivalent Proportional Counters (TEPCs) presently being utilized on the International Space Station (ISS) and Space Shuttle, enabling them to become personal crew dosimeters. The miniaturized TEPC prototype design has dimensions of 7.6 x 10.1 x 2.54 cm (3 x 4 x 1 in). It is composed of a 3 x 4 array of 1.27 cm (0.5 in) spherical detectors for measurements equivalent to a 4.39 cm (1.73 in) spherical detector, with an additional standalone sphere of diameter 1.27 cm (0.5 in) for taking measurements in high-flux environments. The detector simulates a tissue-equivalent diameter of 2 microns, is sensitive to lineal energies of 0.3 -- 1000 keV/micron, and can measure charged particles and neutrons ranging from 0.01 -- 100 mGy/hr.

  20. Interpretation and use of electrical equivalent circuits in studies of epithelial tissues.

    PubMed

    Helman, S I; Thompson, S M

    1982-12-01

    Whereas transepithelial and intracellular voltages continue to be measured in renal and other epithelial tissues, the origins of these voltages, especially in renal epithelia, remain obscure. Because epithelial tissues have multiple transcellular and extracellular routes of ion transport, it is convenient to model them with electrical equivalent circuits and, in this way, attempt to understand the relative importance of and relationships between the parallel-series arrangements of the membranes and barriers involved. The interpretation of the equivalent electromotive forces and resistances can be complicated, however, by virtue of nonlinear current-voltage relationships of ionic channels. Thus, for ion transport pathways displaying nonlinear I-V relationships, it is important to distinguish between chord and slope formalisms in the use and interpretation of electrophysiological data. For ions like Na that are generally not at electrochemical equilibrium, the Thévenin electromotive force (emf) of the slope formalism is not synonymous with the Nernst equilibrium potential of the chord formalism nor are the slope and chord conductances equal or constant at all voltages. Thus, it is mandatory that the empirical data be calculated and interpreted in a way consistent with the formalism adopted. The existence of nonlinear behavior, characterized by either Goldman or other types of rectification, exacerbates determination of relative ionic permeabilities, fractional resistances, transference numbers, and other electrophysiological parameters for simple membranes and especially for epithelia. It is argued that the use and interpretation of electrical equivalent circuits of epithelia are not arbitrary but must take into account nonlinearities of the ionic current-voltage relationships and concentration and voltage dependencies of the emfs and conductances. PMID:6293312

  1. Multiscale strain analysis of tissue equivalents using a custom-designed biaxial testing device.

    PubMed

    Bell, B J; Nauman, E; Voytik-Harbin, S L

    2012-03-21

    Mechanical signals transferred between a cell and its extracellular matrix play an important role in regulating fundamental cell behavior. To further define the complex mechanical interactions between cells and matrix from a multiscale perspective, a biaxial testing device was designed and built. Finite element analysis was used to optimize the cruciform specimen geometry so that stresses within the central region were concentrated and homogenous while minimizing shear and grip effects. This system was used to apply an equibiaxial loading and unloading regimen to fibroblast-seeded tissue equivalents. Digital image correlation and spot tracking were used to calculate three-dimensional strains and associated strain transfer ratios at macro (construct), meso, matrix (collagen fibril), cell (mitochondria), and nuclear levels. At meso and matrix levels, strains in the 1- and 2-direction were statistically similar throughout the loading-unloading cycle. Interestingly, a significant amplification of cellular and nuclear strains was observed in the direction perpendicular to the cell axis. Findings indicate that strain transfer is dependent upon local anisotropies generated by the cell-matrix force balance. Such multiscale approaches to tissue mechanics will assist in advancement of modern biomechanical theories as well as development and optimization of preconditioning regimens for functional engineered tissue constructs. PMID:22455913

  2. Limit of Detection in X-ray Diffraction Measurements of Tissue Equivalent Samples

    NASA Astrophysics Data System (ADS)

    Zheng, Y.; Vassiljev, N.; Konstantinidis, A.; Griffiths, J.; Speller, R.

    2015-09-01

    There is a suggestion of a new approach to mammography whereby following a conventional mammogram, the radiologist could interrogate suspicious regions using X-ray diffraction whilst the patient is still present and to establish the true extent of disease. A starting point for this work is to quantify the minimum detectable amount of breast cancer within a realistic thickness phantom. Perspex has a similar diffraction pattern to healthy breast tissue whilst water is similar to breast tumour, hence these two materials are used as tissue equivalent test objects for X-ray diffraction measurements. The preliminary results show linear agreement between the ratio of Perspex to water and the ratio of the diffraction peak intensities at 0.7 nm-1 and 1.5 nm-1. The minimum detectable limit for a component of the two ‘tissue’ mix was found to be 4.1%. This suggests that X-ray diffraction can be used to quantify tissue like mixtures down to the 4.1% / 95.9% mix level and hence has a strong potential for delineating the extent of infiltration disease.

  3. Stability of A-150 plastic ionization chamber response over a ~30 year period

    SciTech Connect

    Kroc, Thomas K.; Lennox, Arlene J.; /Fermilab

    2007-08-01

    At the NIU Institute for Neutron Therapy at Fermilab, the clinical tissue-equivalent ionization chamber response is measured every treatment day using a cesium source that was configured to match readings obtained at the National Bureau of Standards. Daily measurements are performed in air using the air-to-tissue dose conversion factors given in AAPM Report no. 7. The measured exposure calibration factors have been tabulated and graphed as a function of time from 1978 to present. For A-150 plastic ionization chambers, these factors exhibit a sinusoidal variation with a period of approximately one year and amplitude of {+-} 1%. This variation, attributable to the hygroscopic nature of A-150 plastic, is correlated with the relative humidity of the facility, and is greater than the humidity corrections for gas described in the literature. Our data suggest that chamber calibration should be performed at least weekly to accommodate these variations.

  4. Investigation on Tissue Equivalent Normoxic Polymer Gel Dosimeter using In-house Laser CT scanning system

    NASA Astrophysics Data System (ADS)

    Senthil Kumar, D.; Jebaseelan Samuel, E. James

    2010-11-01

    Optical Computed Tomography has wide applications in the treatment of cancer. In continuation of this, an in-house Laser CT scanner has been built for "3D gel dosimetry". The Laser CT (LCT) scanner plays a major for Gel dosimeter or phantom readout and in clinical radiation therapy as a 3-Dimensional Radiation Dosimetry. A gel dosimeter which absorbs dose in a tissue-equivalent manner and allows the measurement of spatial distribution of the deposited dose is required. The normoxic PAGAT (Polyacrylamide Gelatin and Tetrakis) gel is used as a dosimeter for this analysis. When laser passes through this gel phantom, absorption and scattering takes place and combined to attenuation. The optical attenuation coefficient of the laser can be obtained by measuring its intensity after passing through the gel by means of a sensor. Reconstruction using Mat Lab algorithm provides 3D dose distribution.

  5. Lineal energy calibration of mini tissue-equivalent gas-proportional counters (TEPC)

    SciTech Connect

    Conte, V.; Moro, D.; Colautti, P.; Grosswendt, B.

    2013-07-18

    Mini TEPCs are cylindrical gas proportional counters of 1 mm or less of sensitive volume diameter. The lineal energy calibration of these tiny counters can be performed with an external gamma-ray source. However, to do that, first a method to get a simple and precise spectral mark has to be found and then the keV/{mu}m value of this mark. A precise method (less than 1% of uncertainty) to identify this markis described here, and the lineal energy value of this mark has been measured for different simulated site sizes by using a {sup 137}Cs gamma source and a cylindrical TEPC equipped with a precision internal {sup 244}Cm alpha-particle source, and filled with propane-based tissue-equivalent gas mixture. Mini TEPCs can be calibrated in terms of lineal energy, by exposing them to {sup 137}Cesium sources, with an overall uncertainty of about 5%.

  6. Assessment of doses caused by electrons in thin layers of tissue-equivalent materials, using MCNP.

    PubMed

    Heide, Bernd

    2013-10-01

    Absorbed doses caused by electron irradiation were calculated with Monte Carlo N-Particle transport code (MCNP) for thin layers of tissue-equivalent materials. The layers were so thin that the calculation of energy deposition was on the border of the scope of MCNP. Therefore, in this article application of three different methods of calculation of energy deposition is discussed. This was done by means of two scenarios: in the first one, electrons were emitted from the centre of a sphere of water and also recorded in that sphere; and in the second, an irradiation with the PTB Secondary Standard BSS2 was modelled, where electrons were emitted from an (90)Sr/(90)Y area source and recorded inside a cuboid phantom made of tissue-equivalent material. The speed and accuracy of the different methods were of interest. While a significant difference in accuracy was visible for one method in the first scenario, the difference in accuracy of the three methods was insignificant for the second one. Considerable differences in speed were found for both scenarios. In order to demonstrate the need for calculating the dose in thin small zones, a third scenario was constructed and simulated as well. The third scenario was nearly equal to the second one, but a pike of lead was assumed to be inside the phantom in addition. A dose enhancement (caused by the pike of lead) of ∼113 % was recorded for a thin hollow cylinder at a depth of 0.007 cm, which the basal-skin layer is referred to in particular. Dose enhancements between 68 and 88 % were found for a slab with a radius of 0.09 cm for all depths. All dose enhancements were hardly noticeable for a slab with a cross-sectional area of 1 cm(2), which is usually applied to operational radiation protection. PMID:23576794

  7. Low energy photon attenuation measurements of hydrophilic materials for tissue equivalent phantoms.

    PubMed

    Farquharson, M J; Spyrou, N M; al-Bahri, J; Highgate, D J

    1995-08-01

    The object of the study was to measure the linear attenuation coefficients of hydrophilic materials with the aim of investigating their suitability as tissue equivalent materials. Hydrophilic materials are used in the ophthalmic industry for the manufacture of soft contact lenses. Hydrophilic materials have the trade name "Biogel" and are commonly known as hydrogels. Two types of hydrophilic material were tested, ED4C (72% water uptake by weight) and EDIS (60% water uptake by weight). The measurements were obtained using gamma-ray photons of energy 59.5 keV, and x-ray photons of energies 44.23 and 17.44 keV. Measurements were made for material types ED4C and EDIS in both the dry and fully hydrated state. Measurements were also made on powdered samples of ED4C at different hydration levels using a photon energy of 17.44 keV and powdered samples of EDIS at different hydration levels using a photon energy of 59.5 keV. The precision of the measurements was approx. 1%. It was found that material ED4C has linear attenuation coefficients that closely match those of the calculated values for soft tissue across the range of energies used. PMID:7633393

  8. Human corneal stromal stem cells support limbal epithelial cells cultured on RAFT tissue equivalents

    PubMed Central

    Kureshi, Alvena K; Dziasko, Marc; Funderburgh, James L; Daniels, Julie T

    2015-01-01

    Human limbal epithelial cells (HLE) and corneal stromal stem cells (CSSC) reside in close proximity in vivo in the corneal limbal stem cell niche. However, HLE are typically cultured in vitro without supporting niche cells. Here, we re-create the cell-cell juxtaposition of the native environment in vitro, to provide a tool for investigation of epithelial-stromal cell interactions and to optimize HLE culture conditions for potential therapeutic application. RAFT (Real Architecture For 3D Tissue) tissue equivalents (TEs) were used as a 3-dimensional substrate for co-culturing HLE and CSSC. Our results demonstrate that a monolayer of HLE that maintained expression of p63α, ABCB5, CK8 and CK15 (HLE markers), formed on the surface of RAFT TEs within 13 days of culture. CSSC remained in close proximity to HLE and maintained expression of mesenchymal stem cell markers. This simple technique has a short preparation time of only 15 days with the onset of HLE layering and differentiation observed. Furthermore, co-cultivation of HLE with another niche cell type (CSSC) directly on RAFT TEs, eliminates the requirement for animal-derived feeder cells. RAFT TEs may be useful for future therapeutic delivery of multiple cell types to restore the limbal niche following ocular surface injury or disease. PMID:26531048

  9. Estimation of the effects of normal tissue sparing using equivalent uniform dose-based optimization.

    PubMed

    Senthilkumar, K; Maria Das, K J; Balasubramanian, K; Deka, A C; Patil, B R

    2016-01-01

    In this study, we intend to estimate the effects of normal tissue sparing between intensity modulated radiotherapy (IMRT) treatment plans generated with and without a dose volume (DV)-based physical cost function using equivalent uniform dose (EUD). Twenty prostate cancer patients were retrospectively selected for this study. For each patient, two IMRT plans were generated (i) EUD-based optimization with a DV-based physical cost function to control inhomogeneity (EUDWith DV) and (ii) EUD-based optimization without a DV-based physical cost function to allow inhomogeneity (EUDWithout DV). The generated plans were prescribed a dose of 72 Gy in 36 fractions to planning target volume (PTV). Mean dose, D30%, and D5% were evaluated for all organ at risk (OAR). Normal tissue complication probability was also calculated for all OARs using BioSuite software. The average volume of PTV for all patients was 103.02 ± 27 cm(3). The PTV mean dose for EUDWith DV plans was 73.67 ± 1.7 Gy, whereas for EUDWithout DV plans was 80.42 ± 2.7 Gy. It was found that PTV volume receiving dose more than 115% of prescription dose was negligible in EUDWith DV plans, whereas it was 28% in EUDWithout DV plans. In almost all dosimetric parameters evaluated, dose to OARs in EUDWith DV plans was higher than in EUDWithout DV plans. Allowing inhomogeneous dose (EUDWithout DV) inside the target would achieve better normal tissue sparing compared to homogenous dose distribution (EUDWith DV). Hence, this inhomogeneous dose could be intentionally dumped on the high-risk volume to achieve high local control. Therefore, it was concluded that EUD optimized plans offer added advantage of less OAR dose as well as selectively boosting dose to gross tumor volume. PMID:27217624

  10. Fabrication of injectable, cellular, anisotropic collagen tissue equivalents with modular fibrillar densities.

    PubMed

    Marelli, Benedetto; Ghezzi, Chiara E; James-Bhasin, Mark; Nazhat, Showan N

    2015-01-01

    Technological improvements in collagen gel fabrication are highly desirable as they may enable significant advances in the formation of tissue-equivalent biomaterials for regenerative medicine, three-dimensional (3D) in vitro tissue models, and injectable scaffolds for cell and drug delivery applications. Thus, strategies to modulate collagen gel fibrillar density and organization in the mesostructure have been pursued to fabricate collagenous matrices with extracellular matrix-like features. Herein, we introduce a robust and simple method, namely gel aspiration-ejection (GAE), to engineer 3D, anisotropic, cell seeded, injectable dense collagen (I-DC) gels with controllable fibrillar densities, without the use of crosslinking. GAE allows for the hybridization of collagen gels with bioactive agents for increased functionality and supports highly aligned homogenous cell seeding, thus providing I-DC gels with distinct properties when compared to isotropic DC gels of random fibrillar orientation. The hybridization of I-DC with anionic fibroin derived polypeptides resulted in the nucleation of carbonated hydroxyapatite within the aligned nanofibrillar network upon exposure to simulated body fluid, yielding a 3D, anisotropic, mineralized collagen matrix. In addition, I-DC gels accelerated the osteoblastic differentiation of seeded murine mesenchymal stem cells (m-MSCs) when exposed to osteogenic supplements, which resulted in the cell-mediated, bulk mineralization of the osteoid-like gels. In addition, and upon exposure to neuronal transdifferentiation medium, I-DC gels supported and accelerated the differentiation of m-MSCs toward neuronal cells. In conclusion, collagen GAE presents interesting opportunities in a number of fields spanning tissue engineering and regenerative medicine to drug and cell delivery. PMID:25453949

  11. Estimation of the effects of normal tissue sparing using equivalent uniform dose-based optimization

    PubMed Central

    Senthilkumar, K.; Maria Das, K. J.; Balasubramanian, K.; Deka, A. C.; Patil, B. R.

    2016-01-01

    In this study, we intend to estimate the effects of normal tissue sparing between intensity modulated radiotherapy (IMRT) treatment plans generated with and without a dose volume (DV)-based physical cost function using equivalent uniform dose (EUD). Twenty prostate cancer patients were retrospectively selected for this study. For each patient, two IMRT plans were generated (i) EUD-based optimization with a DV-based physical cost function to control inhomogeneity (EUDWith DV) and (ii) EUD-based optimization without a DV-based physical cost function to allow inhomogeneity (EUDWithout DV). The generated plans were prescribed a dose of 72 Gy in 36 fractions to planning target volume (PTV). Mean dose, D30%, and D5% were evaluated for all organ at risk (OAR). Normal tissue complication probability was also calculated for all OARs using BioSuite software. The average volume of PTV for all patients was 103.02 ± 27 cm3. The PTV mean dose for EUDWith DV plans was 73.67 ± 1.7 Gy, whereas for EUDWithout DV plans was 80.42 ± 2.7 Gy. It was found that PTV volume receiving dose more than 115% of prescription dose was negligible in EUDWith DV plans, whereas it was 28% in EUDWithout DV plans. In almost all dosimetric parameters evaluated, dose to OARs in EUDWith DV plans was higher than in EUDWithout DV plans. Allowing inhomogeneous dose (EUDWithout DV) inside the target would achieve better normal tissue sparing compared to homogenous dose distribution (EUDWith DV). Hence, this inhomogeneous dose could be intentionally dumped on the high-risk volume to achieve high local control. Therefore, it was concluded that EUD optimized plans offer added advantage of less OAR dose as well as selectively boosting dose to gross tumor volume. PMID:27217624

  12. Operation of gas electron multiplier (GEM) with propane gas at low pressure and comparison with tissue-equivalent gas mixtures

    NASA Astrophysics Data System (ADS)

    De Nardo, L.; Farahmand, M.

    2016-05-01

    A Tissue-Equivalent Proportional Counter (TEPC), based on a single GEM foil of standard geometry, has been tested with pure propane gas at low pressure, in order to simulate a tissue site of about 1 μm equivalent size. In this work, the performance of GEM with propane gas at a pressure of 21 and 28 kPa will be presented. The effective gas gain was measured in various conditions using a 244Cm alpha source. The dependence of effective gain on the electric field strength along the GEM channel and in the drift and induction region was investigated. A maximum effective gain of about 5×103 has been reached. Results obtained in pure propane gas are compared with gas gain measurements in gas mixtures commonly employed in microdosimetry, that is propane and methane based Tissue-Equivalent gas mixtures.

  13. Microdosimetry study of THOR BNCT beam using tissue equivalent proportional counter.

    PubMed

    Hsu, F Y; Hsiao, H W; Tung, C-J; Liu, H M; Chou, F I

    2009-07-01

    Boron neutron capture therapy (BNCT) is a cancer treatment modality using a nuclear reactor and a boron compound drug. In Taiwan, Tsing Hua open-pool reactor (THOR) has been modulated for the basic research of BNCT for years. A new BNCT beam port was built in 2004 and used to prepare the first clinical trial in the near future. This work reports the microdosimetry study of the THOR BNCT beam by means of the tissue equivalent proportional counter (TEPC). Two self-fabricated TEPCs (the boron-doped versus the boron-free counter wall) were introduced. These dual TEPCs were applied to measure the lineal energy distributions in air and water phantom irradiated by the THOR BNCT mixed radiation field. Dose contributions from component radiations of different linear energy transfers (LETs) were analyzed. Applying a lineal energy dependent biological weighting function, r(y), to the total and individual lineal energy distributions, the effective relative biological effectiveness (RBE), neutron RBE, photon RBE, and boron capture RBE (BNC RBE) were all determined at various depths of the water phantom. Minimum and maximum values of the effective RBE were 1.68 and 2.93, respectively. The maximum effective RBE occurred at 2cm depth in the phantom. The average neutron RBE, photon RBE, and BNC RBE values were 3.160+/-0.020, 1.018+/-0.001, and 1.570+/-0.270, respectively, for the THOR BNCT beam. PMID:19447042

  14. Benchmarking computations using the Monte Carlo code ritracks with data from a tissue equivalent proportional counter

    NASA Astrophysics Data System (ADS)

    Brogan, John

    Understanding the dosimetry for high-energy, heavy ions (HZE), especially within living systems, is complex and requires the use of both experimental and computational methods. Tissue-equivalent proportional counters (TEPCs) have been used experimentally to measure energy deposition in volumes similar in dimension to a mammalian cell. As these experiments begin to include a wider range of ions and energies, considerations to cost, time, and radiation protection are necessary and may limit the extent of these studies. Multiple Monte Carlo computational codes have been created to remediate this problem and serve as a mode of verification for pervious experimental methods. One such code, Relativistic-Ion Tracks (RITRACKS), is currently being developed at the NASA Johnson Space center. RITRACKS was designed to describe patterns of ionizations responsible for DNA damage on the molecular scale (nanometers). This study extends RITRACKS version 3.07 into the microdosimetric scale (microns), and compares computational results to previous experimental TEPC data. Energy deposition measurements for 1000 MeV nucleon-1 Fe ions in a 1 micron spherical target were compared. Different settings within RITRACKS were tested to verify their effects on dose to a target and the resulting energy deposition frequency distribution. The results were then compared to the TEPC data.

  15. Compact Tissue-equivalent Proportional Counter for Deep Space Human Missions

    PubMed Central

    Straume, T.; Braby, L.A.; Borak, T.B.; Lusby, T.; Warner, D.W.; Perez-Nunez, D.

    2015-01-01

    Abstract Effects on human health from the complex radiation environment in deep space have not been measured and can only be simulated here on Earth using experimental systems and beams of radiations produced by accelerators, usually one beam at a time. This makes it particularly important to develop instruments that can be used on deep-space missions to measure quantities that are known to be relatable to the biological effectiveness of space radiation. Tissue-equivalent proportional counters (TEPCs) are such instruments. Unfortunately, present TEPCs are too large and power intensive to be used beyond low Earth orbit (LEO). Here, the authors describe a prototype of a compact TEPC designed for deep space applications with the capability to detect both ambient galactic cosmic rays and intense solar particle event radiation. The device employs an approach that permits real-time determination of (and thus quality factor) using a single detector. This was accomplished by assigning sequential sampling intervals as detectors “1” and “2” and requiring the intervals to be brief compared to the change in dose rate. Tests with γ rays show that the prototype instrument maintains linear response over the wide dose-rate range expected in space with an accuracy of better than 5% for dose rates above 3 mGy h−1. Measurements of for 200 MeV n−1 carbon ions were better than 10%. Limited tests with fission spectrum neutrons show absorbed dose-rate accuracy better than 15%. PMID:26313585

  16. Characterization of a Tissue-Equivalent Dosimeter based on CMOS Solid-State Photomultipliers

    NASA Astrophysics Data System (ADS)

    Johnson, Erik; Benton, Eric; Stapels, Christopher; Chrsitian, James; Jie Chen, Xiao

    Available digital dosimeters are bulky and unable to provide real-time monitoring of dose from space radiation. The complexity of space-flight design requires reliable, fault-tolerant equip-ment capable of providing real-time dosimetry during a mission, which is not feasible with the existing thermoluminescent dosimeter (TLD) technology, especially during extravehicular activity (EVA). Real-time monitoring is important for low-Earth orbiting spacecraft and inter-planetary space flight to alert the crew when Solar Particle Events (SPE) increase the particle flux of the spacecraft environment. A dosimeter-on-a-chip for personal dosimetry is comprised of a tissue-equivalent scintillator coupled to a solid-state photomultiplier (SSPM) built using CMOS technology. The radiation sensitive component of the dosimeter is coupled to analog signal processing components and a microprocessor, which can maintain processing fidelity up to 5x105 events per second. The dynamic range of the dosimeter has been verified from 1-GeV protons (0.22 keV/µm in H20) to 420 MeV/n Fe (201.1 keV/µm in H20). The dosimeter confirmed doses to within 3

  17. Calculation of Absorbed Dose in Target Tissue and Equivalent Dose in Sensitive Tissues of Patients Treated by BNCT Using MCNP4C

    NASA Astrophysics Data System (ADS)

    Zamani, M.; Kasesaz, Y.; Khalafi, H.; Pooya, S. M. Hosseini

    Boron Neutron Capture Therapy (BNCT) is used for treatment of many diseases, including brain tumors, in many medical centers. In this method, a target area (e.g., head of patient) is irradiated by some optimized and suitable neutron fields such as research nuclear reactors. Aiming at protection of healthy tissues which are located in the vicinity of irradiated tissue, and based on the ALARA principle, it is required to prevent unnecessary exposure of these vital organs. In this study, by using numerical simulation method (MCNP4C Code), the absorbed dose in target tissue and the equiavalent dose in different sensitive tissues of a patiant treated by BNCT, are calculated. For this purpose, we have used the parameters of MIRD Standard Phantom. Equiavelent dose in 11 sensitive organs, located in the vicinity of target, and total equivalent dose in whole body, have been calculated. The results show that the absorbed dose in tumor and normal tissue of brain equal to 30.35 Gy and 0.19 Gy, respectively. Also, total equivalent dose in 11 sensitive organs, other than tumor and normal tissue of brain, is equal to 14 mGy. The maximum equivalent doses in organs, other than brain and tumor, appear to the tissues of lungs and thyroid and are equal to 7.35 mSv and 3.00 mSv, respectively.

  18. Tissue Equivalent Proportional Counter Microdosimetry Measurements Utilized Aboard Aircraft and in Accelerator Based Space Radiation Shielding Studies

    NASA Technical Reports Server (NTRS)

    Gersey, Brad B.; Wilkins, Richard T.

    2010-01-01

    This slide presentation reviews the Tissue Equivalent Proportional Counter (TEPC), a description of the spatially restricted LET Model, high energy proton TEPC and the results of modeling, the study of shielding and the results from the flight exposures with the TEPC.

  19. Allometric scaling of dietary linoleic acid on changes in tissue arachidonic acid using human equivalent diets in mice

    PubMed Central

    2011-01-01

    Background It is hypothesized that dietary linoleic acid (LA) promotes chronic and acute diseases in humans by enriching tissues with arachidonic acid (AA), its downstream metabolite, and dietary studies with rodents have been useful for validation. However, levels of LA in research diets of rodents, as published in the literature, are notoriously erratic making interspecies comparisons unreliable. Therefore, the ability to extrapolate the biological effects of dietary LA from experimental rodents to humans necessitates an allometric scaling model that is rooted within a human equivalent context. Methods To determine the physiological response of dietary LA on tissue AA, a mathematical model for extrapolating nutrients based on energy was used, as opposed to differences in body weight. C57BL/6J mice were divided into 9 groups fed a background diet equivalent to that of the US diet (% energy) with supplemental doses of LA or AA. Changes in the phospholipid fatty acid compositions were monitored in plasma and erythrocytes and compared to data from humans supplemented with equivalent doses of LA or AA. Results Increasing dietary LA had little effect on tissue AA, while supplementing diets with AA significantly increased tissue AA levels, importantly recapitulating results from human trials. Conclusions Thus, interspecies comparisons for dietary LA between rodents and humans can be achieved when rodents are provided human equivalent doses based on differences in metabolic activity as defined by energy consumption. PMID:21702942

  20. Compact Tissue-equivalent Proportional Counter for Deep Space Human Missions.

    PubMed

    Straume, T; Braby, L A; Borak, T B; Lusby, T; Warner, D W; Perez-Nunez, D

    2015-10-01

    Effects on human health from the complex radiation environment in deep space have not been measured and can only be simulated here on Earth using experimental systems and beams of radiations produced by accelerators, usually one beam at a time. This makes it particularly important to develop instruments that can be used on deep-space missions to measure quantities that are known to be relatable to the biological effectiveness of space radiation. Tissue-equivalent proportional counters (TEPCs) are such instruments. Unfortunately, present TEPCs are too large and power intensive to be used beyond low Earth orbit (LEO). Here, the authors describe a prototype of a compact TEPC designed for deep space applications with the capability to detect both ambient galactic cosmic rays and intense solar particle event radiation. The device employs an approach that permits real-time determination of yD (and thus quality factor) using a single detector. This was accomplished by assigning sequential sampling intervals as detectors “1” and “2” and requiring the intervals to be brief compared to the change in dose rate. Tests with g rays show that the prototype instrument maintains linear response over the wide dose-rate range expected in space with an accuracy of better than 5% for dose rates above 3 mGy h(-1). Measurements of yD for 200 MeV n(-1) carbon ions were better than 10%. Limited tests with fission spectrum neutrons show absorbed dose-rate accuracy better than 15%. PMID:26313585

  1. Determination of tissue equivalent materials of a physical 8-year-old phantom for use in computed tomography

    NASA Astrophysics Data System (ADS)

    Akhlaghi, Parisa; Miri Hakimabad, Hashem; Rafat Motavalli, Laleh

    2015-07-01

    This paper reports on the methodology applied to select suitable tissue equivalent materials of an 8-year phantom for use in computed tomography (CT) examinations. To find the appropriate tissue substitutes, first physical properties (physical density, electronic density, effective atomic number, mass attenuation coefficient and CT number) of different materials were studied. Results showed that, the physical properties of water and polyurethane (as soft tissue), B-100 and polyvinyl chloride (PVC) (as bone) and polyurethane foam (as lung) agree more with those of original tissues. Then in the next step, the absorbed doses in the location of 25 thermoluminescent dosimeters (TLDs) as well as dose distribution in one slice of phantom were calculated for original and these proposed materials by Monte Carlo simulation at different tube voltages. The comparisons suggested that at tube voltages of 80 and 100 kVp using B-100 as bone, water as soft tissue and polyurethane foam as lung is suitable for dosimetric study in pediatric CT examinations. In addition, it was concluded that by considering just the mass attenuation coefficient of different materials, the appropriate tissue equivalent substitutes in each desired X-ray energy range could be found.

  2. Dose equivalent near the bone-soft tissue interface from nuclear fragments produced by high-energy protons.

    PubMed

    Shavers, M R; Poston, J W; Cucinotta, F A; Wilson, J W

    1996-04-01

    During manned space missions, high-energy nucleons of cosmic and solar origin collide with atomic nuclei of the human body and produce a broad linear energy transfer spectrum of secondary particles, called target fragments. These nuclear fragments are often more biologically harmful than the direct ionization of the incident nucleon. That these secondary particles increase tissue absorbed dose in regions adjacent to the bone-soft tissue interface was demonstrated in a previous publication. To assess radiological risks to tissue near the bone-soft tissue interface, a computer transport model for nuclear fragments produced by high energy nucleons was used in this study to calculate integral linear energy transfer spectra and dose equivalents resulting from nuclear collisions of 1-GeV protons transversing bone and red bone marrow. In terms of dose equivalent averaged over trabecular bone marrow, target fragments emitted from interactions in both tissues are predicted to be at least as important as the direct ionization of the primary protons-twice as important, if recently recommended radiation weighting factors and "worst-case" geometry are used. The use of conventional dosimetry (absorbed dose weighted by aa linear energy transfer-dependent quality factor) as an appropriate framework for predicting risk from low fluences of high-linear energy transfer target fragments is discussed. PMID:8617586

  3. Dose equivalent near the bone-soft tissue interface from nuclear fragments produced by high-energy protons

    NASA Technical Reports Server (NTRS)

    Shavers, M. R.; Poston, J. W.; Cucinotta, F. A.; Wilson, J. W.

    1996-01-01

    During manned space missions, high-energy nucleons of cosmic and solar origin collide with atomic nuclei of the human body and produce a broad linear energy transfer spectrum of secondary particles, called target fragments. These nuclear fragments are often more biologically harmful than the direct ionization of the incident nucleon. That these secondary particles increase tissue absorbed dose in regions adjacent to the bone-soft tissue interface was demonstrated in a previous publication. To assess radiological risks to tissue near the bone-soft tissue interface, a computer transport model for nuclear fragments produced by high energy nucleons was used in this study to calculate integral linear energy transfer spectra and dose equivalents resulting from nuclear collisions of 1-GeV protons transversing bone and red bone marrow. In terms of dose equivalent averaged over trabecular bone marrow, target fragments emitted from interactions in both tissues are predicted to be at least as important as the direct ionization of the primary protons-twice as important, if recently recommended radiation weighting factors and "worst-case" geometry are used. The use of conventional dosimetry (absorbed dose weighted by aa linear energy transfer-dependent quality factor) as an appropriate framework for predicting risk from low fluences of high-linear energy transfer target fragments is discussed.

  4. Quantification of biological tissue and construction of patient equivalent phantom (skull and chest) for infants (1-5 years old)

    NASA Astrophysics Data System (ADS)

    Alves, A. F.; Pina, D. R.; Bacchim Neto, F. A.; Ribeiro, S. M.; Miranda, J. R. A.

    2014-03-01

    Our main purpose in this study was to quantify biological tissue in computed tomography (CT) examinations with the aim of developing a skull and a chest patient equivalent phantom (PEP), both specific to infants, aged between 1 and 5 years old. This type of phantom is widely used in the development of optimization procedures for radiographic techniques, especially in computed radiography (CR) systems. In order to classify and quantify the biological tissue, we used a computational algorithm developed in Matlab ®. The algorithm performed a histogram of each CT slice followed by a Gaussian fitting of each tissue type. The algorithm determined the mean thickness for the biological tissues (bone, soft, fat, and lung) and also converted them into the corresponding thicknesses of the simulator material (aluminum, PMMA, and air). We retrospectively analyzed 148 CT examinations of infant patients, 56 for skull exams and 92 were for chest. The results provided sufficient data to construct a phantom to simulate the infant chest and skull in the posterior-anterior or anterior-posterior (PA/AP) view. Both patient equivalent phantoms developed in this study can be used to assess physical variables such as noise power spectrum (NPS) and signal to noise ratio (SNR) or perform dosimetric control specific to pediatric protocols.

  5. Biofabrication of osteochondral tissue equivalents by printing topologically defined, cell-laden hydrogel scaffolds.

    PubMed

    Fedorovich, Natalja E; Schuurman, Wouter; Wijnberg, Hans M; Prins, Henk-Jan; van Weeren, P René; Malda, Jos; Alblas, Jacqueline; Dhert, Wouter J A

    2012-01-01

    Osteochondral defects are prone to induce osteoarthritic degenerative changes. Many tissue-engineering approaches that aim to generate osteochondral implants suffer from poor tissue formation and compromised integration. This illustrates the need for further improvement of heterogeneous tissue constructs. Engineering of these structures is expected to profit from strategies addressing the complexity of tissue organization and the simultaneous use of multiple cell types. Moreover, this enables the investigation of the effects of three-dimensional (3D) organization and architecture on tissue function. In the present study, we characterize the use of a 3D fiber deposition (3DF) technique for the fabrication of cell-laden, heterogeneous hydrogel constructs for potential use as osteochondral grafts. Changing fiber spacing or angle of fiber deposition yielded scaffolds of varying porosity and elastic modulus. We encapsulated and printed fluorescently labeled human chondrocytes and osteogenic progenitors in alginate hydrogel yielding scaffolds of 1×2 cm with different parts for both cell types. Cell viability remained high throughout the printing process, and cells remained in their compartment of the printed scaffold for the whole culture period. Moreover, distinctive tissue formation was observed, both in vitro after 3 weeks and in vivo (6 weeks subcutaneously in immunodeficient mice), at different locations within one construct. These results demonstrate the possibility of manufacturing viable centimeter-scaled structured tissues by the 3DF technique, which could potentially be used for the repair of osteochondral defects. PMID:21854293

  6. Calibration of a large hyperpure germanium array for in-vivo detection of the actinides with a tissue-equivalent torso phantom

    SciTech Connect

    Berger, C.D.; Lane, B.H.

    1983-01-01

    For calibration of the array for internally deposited /sup 238/Pu, /sup 239/Pu, and /sup 241/Am, a tissue-equivalent anthropomorphic phantom, was used for efficiency determinations at the ORNL facility. This phantom consists of a tissue-equivalent torso into which is imbedded an adult male skeleton, interchangeable organs containing a homogeneous distribution of various radionuclides, and two sets of chest overlay plates for simulation of progressively thicker tissue over the chest, as well as differing thoracic fat contents. (PSB)

  7. Equivalent of a cartilage tissue for simulations of laser-induced temperature fields

    SciTech Connect

    Kondyurin, A V; Sviridov, A P

    2008-07-31

    The thermal and optical properties of polyacrylamide hydrogels and cartilages are studied by the method of IR laser radiometry. The thermal diffusivity, heat capacity, and the effective absorption coefficient at a wavelength of 1.56 {mu}m measured for polyacrylamide gel with 70% water content and the degree of cross-linking 1:9 and for the nasal septum cartilage proved to be close. This allows the use of polyacrylamide hydrogels as equivalents of cartilages in simulations of laser-induced temperature fields. (biophotonics)

  8. An electrically-activated dynamic tissue-equivalent phantom for assessment of diffuse optical imaging systems.

    PubMed

    Hebden, Jeremy C; Brunker, Joanna; Correia, Teresa; Price, Ben D; Gibson, Adam P; Everdell, N L

    2008-01-21

    A novel design of solid dynamic phantom with tissue-like optical properties is presented, which contains variable regions of contrast which are activated electrically. Reversible changes in absorption are produced by localized heating of targets impregnated with thermochromic pigment. A portable, battery-operated prototype has been constructed, and its optical and temporal characteristics have been investigated. The phantom has been developed as a means of assessing the performance of diffuse optical imaging systems, such as those used to monitor haemodynamic changes in the brain and other tissues. Images of the phantom have been reconstructed using data acquired with a continuous wave optical topography system. PMID:18184989

  9. An electrically-activated dynamic tissue-equivalent phantom for assessment of diffuse optical imaging systems

    NASA Astrophysics Data System (ADS)

    Hebden, Jeremy C.; Brunker, Joanna; Correia, Teresa; Price, Ben D.; Gibson, Adam P.; Everdell, N. L.

    2008-01-01

    A novel design of solid dynamic phantom with tissue-like optical properties is presented, which contains variable regions of contrast which are activated electrically. Reversible changes in absorption are produced by localized heating of targets impregnated with thermochromic pigment. A portable, battery-operated prototype has been constructed, and its optical and temporal characteristics have been investigated. The phantom has been developed as a means of assessing the performance of diffuse optical imaging systems, such as those used to monitor haemodynamic changes in the brain and other tissues. Images of the phantom have been reconstructed using data acquired with a continuous wave optical topography system.

  10. Simultaneous optical coherence and multiphoton microscopy of skin-equivalent tissue models

    NASA Astrophysics Data System (ADS)

    Barton, Jennifer K.; Tang, Shuo; Lim, Ryan; Tromberg, Bruce J.

    2007-07-01

    Three-layer skin-equivalent models (rafts) were created consisting of a collagen/fibroblast layer and an air-exposed keratinocyte layer. Rafts were imaged with a tri-modality microscope including optical coherence (OC), two-photon excited fluorescence (TPEF), and second harmonic generation (SHG) channels. Some rafts were stained with Hoechst 33343 or rhodamine 123, and some were exposed to dimethyl sulfoxide (DMSO). OC microscopy revealed signal in cell cytoplasm and nuclear membranes, and a characteristic texture in the collagen/fibroblast layer. TPEF showed signal in cell cytoplasm and from collagen, and stained specimens revealed cell nuclei or mitochondria. There was little SHG in the keratinocyte layer, but strong signal from collagen bundles. Endogenous signals were severely attenuated in DMSO treated rafts; stained samples revealed shrunken and distorted cell structure. OC, TPEF, and SHG can provide complementary and non-destructive information about raft structure and effect of chemical agents.

  11. Optical coherence tomography detection of shear wave propagation in inhomogeneous tissue equivalent phantoms and ex-vivo carotid artery samples

    PubMed Central

    Razani, Marjan; Luk, Timothy W.H.; Mariampillai, Adrian; Siegler, Peter; Kiehl, Tim-Rasmus; Kolios, Michael C.; Yang, Victor X.D.

    2014-01-01

    In this work, we explored the potential of measuring shear wave propagation using optical coherence elastography (OCE) in an inhomogeneous phantom and carotid artery samples based on a swept-source optical coherence tomography (OCT) system. Shear waves were generated using a piezoelectric transducer transmitting sine-wave bursts of 400 μs duration, applying acoustic radiation force (ARF) to inhomogeneous phantoms and carotid artery samples, synchronized with a swept-source OCT (SS-OCT) imaging system. The phantoms were composed of gelatin and titanium dioxide whereas the carotid artery samples were embedded in gel. Differential OCT phase maps, measured with and without the ARF, detected the microscopic displacement generated by shear wave propagation in these phantoms and samples of different stiffness. We present the technique for calculating tissue mechanical properties by propagating shear waves in inhomogeneous tissue equivalent phantoms and carotid artery samples using the ARF of an ultrasound transducer, and measuring the shear wave speed and its associated properties in the different layers with OCT phase maps. This method lays the foundation for future in-vitro and in-vivo studies of mechanical property measurements of biological tissues such as vascular tissues, where normal and pathological structures may exhibit significant contrast in the shear modulus. PMID:24688822

  12. Fabrication of 3D tissue equivalent: an in vitro platform for understanding collagen evolution in healthy and diseased models

    NASA Astrophysics Data System (ADS)

    Urciuolo, F.; Imparato, G.; Casale, C.; Scamardella, S.; Netti, P.

    2013-04-01

    In this study we realized a three-dimensional human dermis equivalent (3D-HDE) and, by exploiting multi-photon microscopy (MPM) we validated its use as an in vitro model to study collagen network re-arrangement under simulated solar exposure. The realization of 3D-HDE has been pursed by means of a bottom-up tissue engineering strategy that comprises firstly the fabrication of micron sized tissue building blocks and then their assembly in a 3D tissue construct. The building blocks injected in a maturation chamber, and cultured under optimized culture condition, were able to fuse due to the establishment of cell-cell and cell-extra cellular matrix (ECM) interactions that induced a biological sintering process resulting in 3D-HDE production. The final 3D tissue was made-up by fibroblasts embedded in their own ECM rich in endogenous collagen type I, resembling the composition and the architecture of native human dermis. Second Harmonic Generation (SHG) and Two-Photon Excited Fluorescence (TPEF) imaging have been exploited to assess modification in collagen assembly before and after UV irradiation. Textural features and SHG to TPFE ratio of the endogenous ECM within 3D-HDE have been shown to vary after UVA irradiation, proving the hypothesis that the 3DHDE realized can be used as biological platform in vitro to study ECM modifications induced by photo-damage.

  13. Feasibility of optical coherence elastography measurements of shear wave propagation in homogeneous tissue equivalent phantoms

    PubMed Central

    Razani, Marjan; Mariampillai, Adrian; Sun, Cuiru; Luk, Timothy W. H.; Yang, Victor X. D.; Kolios, Michael C.

    2012-01-01

    In this work, we explored the potential of measuring shear wave propagation using optical coherence elastography (OCE) based on a swept-source optical coherence tomography (OCT) system. Shear waves were generated using a 20 MHz piezoelectric transducer (circular element 8.5 mm diameter) transmitting sine-wave bursts of 400 μs, synchronized with the OCT swept source wavelength sweep. The acoustic radiation force (ARF) was applied to two gelatin phantoms (differing in gelatin concentration by weight, 8% vs. 14%). Differential OCT phase maps, measured with and without the ARF, demonstrate microscopic displacement generated by shear wave propagation in these phantoms of different stiffness. We present preliminary results of OCT derived shear wave propagation velocity and modulus, and compare these results to rheometer measurements. The results demonstrate the feasibility of shear wave OCE (SW-OCE) for high-resolution microscopic homogeneous tissue mechanical property characterization. PMID:22567590

  14. Feasibility of optical coherence elastography measurements of shear wave propagation in homogeneous tissue equivalent phantoms.

    PubMed

    Razani, Marjan; Mariampillai, Adrian; Sun, Cuiru; Luk, Timothy W H; Yang, Victor X D; Kolios, Michael C

    2012-05-01

    In this work, we explored the potential of measuring shear wave propagation using optical coherence elastography (OCE) based on a swept-source optical coherence tomography (OCT) system. Shear waves were generated using a 20 MHz piezoelectric transducer (circular element 8.5 mm diameter) transmitting sine-wave bursts of 400 μs, synchronized with the OCT swept source wavelength sweep. The acoustic radiation force (ARF) was applied to two gelatin phantoms (differing in gelatin concentration by weight, 8% vs. 14%). Differential OCT phase maps, measured with and without the ARF, demonstrate microscopic displacement generated by shear wave propagation in these phantoms of different stiffness. We present preliminary results of OCT derived shear wave propagation velocity and modulus, and compare these results to rheometer measurements. The results demonstrate the feasibility of shear wave OCE (SW-OCE) for high-resolution microscopic homogeneous tissue mechanical property characterization. PMID:22567590

  15. A comparison of the measured responses of a tissue-equivalent proportional counter to high energy heavy (HZE) particles and those simulated using the Geant4 Monte Carlo code

    PubMed Central

    Taddei, Phillip J.; Zhao, Zhongxiang; Borak, Thomas B.

    2010-01-01

    Monte Carlo simulations of heavy ion interactions using the Geant4 toolkit were compared with measurements of energy deposition in a spherical tissue-equivalent proportional counter (TEPC). A spherical cavity with a physical diameter of 12.7 mm was filled with propane-based tissue-equivalent gas surrounded by a wall of A-150 tissue-equivalent plastic that was 2.54 mm to thick. Measurements and Monte Carlo simulations were used to record the energy deposition and the trajectory of the incident particle on an event-by-event basis for ions ranging in atomic number from 2 (4He) to 26 (56Fe) and in energy from 200 MeV/nucleon to 1000 MeV/nucleon. In the simulations, tracking of secondary electrons was terminated when the range of an electron was below a specified threshold. The effects of range cuts for electrons at 0.5 μm, 1 μm, 10 μm, and 100 μm were evaluated. To simulate an energy deposition influenced by large numbers of low energy electrons with large transverse momentum, it was necessary to track electrons down to range cuts of 10 μm or less. The Geant4 simulated data closely matched the measured data acquired using a TEPC for incident particles traversing the center of the detector as well as near the gas-wall interface. Values of frequency mean lineal energy and dose mean lineal energy were within 8% of the measured data. The production of secondary particles in the aluminum vacuum chamber had no effect on the response of the TEPC for 56Fe at 1000 MeV/nucleon. The results of this study confirm that Geant4 can simulate patterns of energy deposition for existing microdosimeters and is valuable for improving the design of a new generation of detectors used for space dosimetry and for characterizing particle beams used in hadron radiotherapy. PMID:20862212

  16. A comparison of the measured responses of a tissue-equivalent proportional counter to high energy heavy (HZE) particles and those simulated using the Geant4 Monte Carlo code.

    PubMed

    Taddei, Phillip J; Zhao, Zhongxiang; Borak, Thomas B

    2008-10-01

    Monte Carlo simulations of heavy ion interactions using the Geant4 toolkit were compared with measurements of energy deposition in a spherical tissue-equivalent proportional counter (TEPC). A spherical cavity with a physical diameter of 12.7 mm was filled with propane-based tissue-equivalent gas surrounded by a wall of A-150 tissue-equivalent plastic that was 2.54 mm to thick. Measurements and Monte Carlo simulations were used to record the energy deposition and the trajectory of the incident particle on an event-by-event basis for ions ranging in atomic number from 2 ((4)He) to 26 ((56)Fe) and in energy from 200 MeV/nucleon to 1000 MeV/nucleon. In the simulations, tracking of secondary electrons was terminated when the range of an electron was below a specified threshold. The effects of range cuts for electrons at 0.5 μm, 1 μm, 10 μm, and 100 μm were evaluated. To simulate an energy deposition influenced by large numbers of low energy electrons with large transverse momentum, it was necessary to track electrons down to range cuts of 10 μm or less. The Geant4 simulated data closely matched the measured data acquired using a TEPC for incident particles traversing the center of the detector as well as near the gas-wall interface. Values of frequency mean lineal energy and dose mean lineal energy were within 8% of the measured data. The production of secondary particles in the aluminum vacuum chamber had no effect on the response of the TEPC for (56)Fe at 1000 MeV/nucleon. The results of this study confirm that Geant4 can simulate patterns of energy deposition for existing microdosimeters and is valuable for improving the design of a new generation of detectors used for space dosimetry and for characterizing particle beams used in hadron radiotherapy. PMID:20862212

  17. Measurement of characteristic prompt gamma rays emitted from oxygen and carbon in tissue-equivalent samples during proton beam irradiation

    NASA Astrophysics Data System (ADS)

    Polf, Jerimy C.; Panthi, Rajesh; Mackin, Dennis S.; McCleskey, Matt; Saastamoinen, Antti; Roeder, Brian T.; Beddar, Sam

    2013-09-01

    The purpose of this work was to characterize how prompt gamma (PG) emission from tissue changes as a function of carbon and oxygen concentration, and to assess the feasibility of determining elemental concentration in tissues irradiated with proton beams. For this study, four tissue-equivalent water-sucrose samples with differing densities and concentrations of carbon, hydrogen, and oxygen were irradiated with a 48 MeV proton pencil beam. The PG spectrum emitted from each sample was measured using a high-purity germanium detector, and the absolute detection efficiency of the detector, average beam current, and delivered dose distribution were also measured. Changes to the total PG emission from 12C (4.44 MeV) and 16O (6.13 MeV) per incident proton and per Gray of absorbed dose were characterized as a function of carbon and oxygen concentration in the sample. The intensity of the 4.44 MeV PG emission per incident proton was found to be nearly constant for all samples regardless of their carbon concentration. However, we found that the 6.13 MeV PG emission increased linearly with the total amount (in grams) of oxygen irradiated in the sample. From the measured PG data, we determined that 1.64 × 107 oxygen PGs were emitted per gram of oxygen irradiated per Gray of absorbed dose delivered with a 48 MeV proton beam. These results indicate that the 6.13 MeV PG emission from 16O is proportional to the concentration of oxygen in tissue irradiated with proton beams, showing that it is possible to determine the concentration of oxygen within tissues irradiated with proton beams by measuring 16O PG emission.

  18. Measurement of characteristic prompt gamma rays emitted from oxygen and carbon in tissue-equivalent samples during proton beam irradiation

    PubMed Central

    Polf, Jerimy C; Panthi, Rajesh; Mackin, Dennis S; McCleskey, Matt; Saastamoinen, Antti; Roeder, Brian T; Beddar, Sam

    2013-01-01

    The purpose of this work was to characterize how prompt gamma (PG) emission from tissue changes as a function of carbon and oxygen concentration, and to assess the feasibility of determining elemental concentration in tissues irradiated with proton beams. For this study, four tissue-equivalent water-sucrose samples with differing densities and concentrations of carbon, hydrogen, and oxygen were irradiated with a 48 MeV proton pencil beam. The PG spectrum emitted from each sample was measured using a high-purity germanium detector, and the absolute detection efficiency of the detector, average beam current, and delivered dose distribution were also measured. Changes to the total PG emission from 12C (4.44 MeV) and 16O (6.13 MeV) per incident proton and per Gray of absorbed dose were characterized as a function of carbon and oxygen concentration in the sample. The intensity of the 4.44 MeV PG emission per incident proton was found to be nearly constant for all samples regardless of their carbon concentration. However, we found that the 6.13 MeV PG emission increased linearly with the total amount (in grams) of oxygen irradiated in the sample. From the measured PG data, we determined that 1.64 × 107 oxygen PGs were emitted per gram of oxygen irradiated per Gray of absorbed dose delivered with a 48 MeV proton beam. These results indicate that the 6.13 MeV PG emission from 16O is proportional to the concentration of oxygen in tissue irradiated with proton beams, showing that it is possible to determine the concentration of oxygen within tissues irradiated with proton beams by measuring 16O PG emission. PMID:23920051

  19. Novel integrative methodology for engineering large liver tissue equivalents based on three-dimensional scaffold fabrication and cellular aggregate assembly.

    PubMed

    Pang, Y; Horimoto, Y; Sutoko, S; Montagne, K; Shinohara, M; Mathiue, D; Komori, K; Anzai, M; Niino, T; Sakai, Yasuyuki

    2016-01-01

    A novel engineering methodology for organizing a large liver tissue equivalent was established by intergrating both 'top down' and 'bottom up' approaches. A three-dimensional (3D) scaffold was engineered comprising 43 culture chambers (volume: 11.63 cm(3)) assembled in a symmetrical pattern on 3 layers, a design which enables further scaling up of the device to a clinically significant size (volume: 500 cm(3)). In addition, an inter-connected flow channel network was designed and proved to homogenously deliver culture medium to each chamber with the same pressure drop. After fabrication using nylon-12 and a selective laser sintering process, co-cultured cellular aggregates of human hepatoma Hep G2 and TMNK-1 cells were loosely packed into the culture chambers with biodegradable poly-L-lactic acid fibre pieces for 9 days of perfusion culture. The device enabled increased hepatic function and well-maintained cell viability, demonstrating the importance of an independent medium flow supply for cell growth and function provided by the current 3D scaffold. This integrative methodology from the macro- to the micro-scale provides an efficient way of arranging engineered liver tissue with improved mass transfer, making it possible to further scale up to a construct with clinically relevant size while maintaining high per-volume-based physiological function in the near future. PMID:27579855

  20. SU-E-T-130: Dosimetric Evaluation of Tissue Equivalent Gel Dosimeter Using Saccharide in Radiotherapy System

    SciTech Connect

    Cho, Y; Lee, D; Jung, H; Ji, Y; Kim, K; Chang, U; Kwon, S

    2014-06-01

    Purpose: In this study, the dose responses of the MAGIC gel with various concentrations and type of saccharide are examined to clarify the roles of mono and disaccharide in the polymerization process. Then we focused on the tissue equivalence and dose sensitivity of MAGIC gel dosimeters. Methods: The gel is composed of HPLC, 8% gelatin, 2 × 10-3 M L-ascorbic acid, 1.8 × 10-2 M hydroquinone, 8 × 10-5 M copper(II)sulfate and 9% methacrylic acid, new polymer gels are synthesized by adding glucose(monosaccharide), sucrose(disaccharide) and urea in the concentration range of 5∼35%. For irradiation of the gel, cesium-137 gamma-ray irradiator was used, radiation dose was delivered from 5∼50 Gy. MRI images of the gel were acquired by using a 3.0 T MRI system. Results: When saccharide and urea were added, the O/C, O/N and C/N ratios agreed with those of soft tissue with 1.7%. The dose-response of glucose and sucrose gel have slope-to-intercept ratio of 0.044 and 0.283 respectively. The slope-to-ratio is one important determinant of gel sensitivity. R-square values of glucose and sucrose gel dosimeters were 0.984 and 0.994 respectively. Moreover when urea were added, the slope-to-intercept ratio is 0.044 and 0.073 respectively. R-square values of mono and disaccharide gel were 0.973 and 0.989 respectively. When a saccharide is added into the MAGIC gel dosimeter, dose sensitivity is increased. However when urea were added, dose sensitivity is slightly decreased. Conclusion: In this study, it was possible to obtain the following conclusions by looking at the dose response characteristics after adding mono-, di-saccharide and urea to a MAGIC gel dosimeter. Saccharide was a tendency of increasing dose sensitivity with disaccharide. Sa.ccharide is cost effective, safe, soft tissue equivalent, and can be used under various experimental conditions, making it a suitable dosimeter for some radiotherapy applications.

  1. Water and tissue equivalence of a new PRESAGE{sup Registered-Sign} formulation for 3D proton beam dosimetry: A Monte Carlo study

    SciTech Connect

    Gorjiara, Tina; Kuncic, Zdenka; Doran, Simon; Adamovics, John; Baldock, Clive

    2012-11-15

    Purpose: To evaluate the water and tissue equivalence of a new PRESAGE{sup Registered-Sign} 3D dosimeter for proton therapy. Methods: The GEANT4 software toolkit was used to calculate and compare total dose delivered by a proton beam with mean energy 62 MeV in a PRESAGE{sup Registered-Sign} dosimeter, water, and soft tissue. The dose delivered by primary protons and secondary particles was calculated. Depth-dose profiles and isodose contours of deposited energy were compared for the materials of interest. Results: The proton beam range was found to be Almost-Equal-To 27 mm for PRESAGE{sup Registered-Sign }, 29.9 mm for soft tissue, and 30.5 mm for water. This can be attributed to the lower collisional stopping power of water compared to soft tissue and PRESAGE{sup Registered-Sign }. The difference between total dose delivered in PRESAGE{sup Registered-Sign} and total dose delivered in water or tissue is less than 2% across the entire water/tissue equivalent range of the proton beam. The largest difference between total dose in PRESAGE{sup Registered-Sign} and total dose in water is 1.4%, while for soft tissue it is 1.8%. In both cases, this occurs at the distal end of the beam. Nevertheless, the authors find that PRESAGE{sup Registered-Sign} dosimeter is overall more tissue-equivalent than water-equivalent before the Bragg peak. After the Bragg peak, the differences in the depth doses are found to be due to differences in primary proton energy deposition; PRESAGE{sup Registered-Sign} and soft tissue stop protons more rapidly than water. The dose delivered by secondary electrons in the PRESAGE{sup Registered-Sign} differs by less than 1% from that in soft tissue and water. The contribution of secondary particles to the total dose is less than 4% for electrons and Almost-Equal-To 1% for protons in all the materials of interest. Conclusions: These results demonstrate that the new PRESAGE{sup Registered-Sign} formula may be considered both a tissue- and water-equivalent

  2. Study of dose distribution in a human body in international space station compartments with the tissue-equivalent spherical phantom

    PubMed Central

    Shurshakov, Vyacheslav A.; Tolochek, Raisa V.; Kartsev, Ivan S.; Petrov, Vladislav M.; Nikolaev, Igor V.; Moskalyova, Svetlana I.; Lyagushin, Vladimir I.

    2014-01-01

    Space radiation is known to be key hazard of manned space mission. To estimate accurately radiation health risk detailed study of dose distribution inside human body by means of human phantom is conducted. In the space experiment MATROSHKA-R, the tissue-equivalent spherical phantom (32 kg mass, 35 cm diameter and 10 cm central spherical cave) made in Russia has been used on board the ISS for more than 8 years. Owing to the specially chosen phantom shape and size, the chord length distributions of the detector locations are attributed to self-shielding properties of the critical organs in a real human body. If compared with the anthropomorphic phantom Rando used inside and outside the ISS, the spherical phantom has lower mass, smaller size and requires less crew time for the detector installation/retrieval; its tissue-equivalent properties are closer to the standard human body tissue than the Rando-phantom material. Originally the spherical phantom was installed in the star board crew cabin of the ISS Service Module, then in the Piers-1, MIM-2 and MIM-1 modules of the ISS Russian segment, and finally in JAXA Kibo module. Total duration of the detector exposure is more than 1700 days in 8 sessions. In the first phase of the experiment with the spherical phantom, the dose measurements were realized with only passive detectors (thermoluminescent and solid-state track detectors). The detectors are placed inside the phantom along the axes of 20 containers and on the phantom outer surface in 32 pockets of the phantom jacket. After each session the passive detectors are returned to the ground. The results obtained show the dose difference on the phantom surface as much as a factor of 2, the highest dose being observed close to the outer wall of the compartment, and the lowest dose being in the opposite location along the phantom diameter. Maximum dose rate measured in the phantom is obviously due to the galactic cosmic ray (GCR) and Earth' radiation belt contribution on

  3. Tissue equivalent proportional counter microdosimetry measurements utililzed aboard aircraft and in accelerator based space radiation shielding studies

    NASA Astrophysics Data System (ADS)

    Gersey, Brad; Wilkins, Richard

    The space radiation environment presents a potential hazard to the humans, electronics and materials that are exposed to it. Particle accelerator facilities such as the NASA Space Ra-diation Laboratory (NSRL) and Loma Linda University Medical Center (LLUMC) provide particle radiation of specie and energy within the range of that found in the space radiation environment. Experiments performed at these facilities determine various endpoints for bio-logical, electronic and materials exposures. A critical factor in the performance of rigorous scientific studies of this type is accurate dosimetric measurements of the exposures. A Tissue Equivalent Proportional Counter (TEPC) is a microdosimeter that may be used to measure absorbed dose, average quality factor (Q) and dose equivalent of the particle beam utilized in these experiments. In this work, results from a variety of space radiation shielding studies where a TEPC was used to perform dosimetry in the particle beam will be presented. These results compare the absorbed dose and dose equivalent measured downstream of equal density thicknesses of stan-dard and multifunctional shielding materials. The standard materials chosen for these shielding studies included High-Density Polyethylene (HDPE) and aluminum alloy, while the multifunc-tional materials included carbon composite infused with single walled carbon nanotubes. High energy particles including proton, silicon and iron nuclei were chosen as the incident radia-tion for these studies. Further, TEPC results from measurements taken during flights aboard ER-2 and KC-135 aircraft will also be discussed. Results from these flight studies include TEPC measurements for shielded and unshielded conditions as well as the effect of vibration and electromagnetic exposures on the TEPC operation. The data selected for presentation will highlight the utility of the TEPC in space radiation studies, and in shielding studies in particular. The lineal energy response function of the

  4. Evolution of the Deep-space Galactic Cosmic Ray Lineal Energy Transfer Spectrum through Tissue Equivalent Plastic

    NASA Astrophysics Data System (ADS)

    Case, A. W.; Kasper, J. C.; Spence, H. E.; Golightly, M. J.; Schwadron, N. A.; Mazur, J. E.; Blake, J. B.; Looper, M. D.; Townsend, L.; Zeitlin, C. J.

    2011-12-01

    The Cosmic Ray Telescope for the Effects of Radiation is an energetic particle telescope that resides on the Lunar Reconnaissance Orbiter spacecraft, currently in a 50 km circular lunar polar orbit. The telescope consists of 6 silicon semi-conductor detectors placed in pairs that surround two pieces of Tissue Equivalent Plastic (TEP), which serve to absorb energy from particles as they transit through the instrument. Particles with energies greater than 12 MeV/nucleon can penetrate the outermost shield and be measured by the instrument. The primary measurement made by the instrument is of the Linear Energy Transfer (LET) of energetic particles as they transit through the telescope. CRaTER measures the LET spectrum with unprecedented energy resolution and has done so during a period of historically low solar activity that led to record high intensities of Galactic Cosmic Rays (GCR). These LET spectra are used to study changes in the properties of the incoming particles, and to make detailed measurements of the radiation doses human explorers will experience in deep space on missions to the moon, to asteroids, or to Mars. We present LET spectra accumulated during 2009 and 2010. We show how the LET spectrum evolves through the instrument as the GCR interact with the TEP. Due to the importance of these measurements for human effects, our extensive absolute calibration procedures are presented. Of particular note is a significant reduction in the flux of particles with LET greater than 10 keV/um for detectors that lie deeper within the telescope stack, due to the attenuation of high LET particles within the TEP. By measuring this attenuation we can estimate the depth in human tissue where the highest LET particles that are most likely to cause genetic damage pose the greatest threat to humans in space.

  5. Fabrication and characterisation of biomimetic, electrospun gelatin fibre scaffolds for tunica media-equivalent, tissue engineered vascular grafts.

    PubMed

    Elsayed, Y; Lekakou, C; Labeed, F; Tomlins, P

    2016-04-01

    It is increasingly recognised that biomimetic, natural polymers mimicking the extracellular matrix (ECM) have low thrombogenicity and functional motifs that regulate cell-matrix interactions, with these factors being critical for tissue engineered vascular grafts especially grafts of small diameter. Gelatin constitutes a low cost substitute of soluble collagen but gelatin scaffolds so far have shown generally low strength and suture retention strength. In this study, we have devised the fabrication of novel, electrospun, multilayer, gelatin fibre scaffolds, with controlled fibre layer orientation, and optimised gelatin crosslinking to achieve not only compliance equivalent to that of coronary artery but also for the first time strength of the wet tubular acellular scaffold (swollen with absorbed water) same as that of the tunica media of coronary artery in both circumferential and axial directions. Most importantly, for the first time for natural scaffolds and in particular gelatin, high suture retention strength was achieved in the range of 1.8-1.94 N for wet acellular scaffolds, same or better than that for fresh saphenous vein. The study presents the investigations to relate the electrospinning process parameters to the microstructural parameters of the scaffold, which are further related to the mechanical performance data of wet, crosslinked, electrospun scaffolds in both circumferential and axial tubular directions. The scaffolds exhibited excellent performance in human smooth muscle cell (SMC) proliferation, with SMCs seeded on the top surface adhering, elongating and aligning along the local fibres, migrating through the scaffold thickness and populating a transverse distance of 186 μm and 240 μm 9 days post-seeding for scaffolds of initial dry porosity of 74 and 83%, respectively. PMID:26838874

  6. The study of simulated microgravity effects on cardiac myocytes using a 3D heart tissue-equivalent model encapsulated in alginate microbeads

    NASA Astrophysics Data System (ADS)

    Li, Yu; Tian, Weiming; Zheng, Hongxia; Yu, Lei; Zhang, Yao; Han, Fengtong

    Long duration spaceflight may increase the risk and occurrence of potentially life-threatening heart rhythm disturbances associated with alterations of cardiac myocytes, myocyte connec-tivity, and extracellular matrix resulting from prolonged exposure to zero-or low-gravity. For understanding of the effects of microgravity, either traditional 2-dimensional (2D) cell cultures of adherent cell populations or animal models were typically used. The 2D in vitro systems do not allow assessment of the dynamic effects of intercellular interactions within tissues, whereas potentially confounding factors tend to be overlooked in animal models. Therefore novel cell culture model representative of the cellular interactions and with extracellular matrix present in tissues needs to be used. In this study, 3D multi-cellular heart tissue-equivalent model was constructed by culturing neonatal rat myocardial cells in alginate microbeads for one week. With this model we studied the simulated microgravity effects on myocardiocytes by incubat-ing the microbeads in NASA rotary cell culture system with a rate of 15rpm. Cytoskeletal changes, mitochondrial membrane potential and reactive oxygen production were studied after incubating for 24h, 48h and 72h respectively. Compared with 3D ground-culture group, sig-nificant cytoskeleton depolymerization characterized by pseudo-feet disappearance, significant increase of mitochondrial membrane potential, and greater reactive oxygen production were observed in after incubating 24h, 48h, and 72h, in NASA system. The beating rate of 3D heart tissue-equivalent decreased significantly at 24h, and all the samples stopped beating after 48h incubation while the beating rate of control group did not change. This study indicated that mi-crogravity affects both the structure and function of myocardial cells. Our results suggest that a 3D heart tissue-equivalent model maybe better for attempting to elucidate the microgravity effects on myocardiocytes in

  7. Tissue engineered pre-vascularized buccal mucosa equivalents utilizing a primary triculture of epithelial cells, endothelial cells and fibroblasts.

    PubMed

    Heller, M; Frerick-Ochs, E V; Bauer, H-K; Schiegnitz, E; Flesch, D; Brieger, J; Stein, R; Al-Nawas, B; Brochhausen, C; Thüroff, J W; Unger, R E; Brenner, W

    2016-01-01

    Artificial generated buccal mucosa equivalents are a promising approach for the reconstruction of urethral defects. Limiting in this approach is a poor blood vessel supply after transplantation, resulting in increased morbidity and necrosis. We generated a pre-vascularized buccal mucosa equivalent in a tri-culture of primary buccal epithelial cells, fibroblasts and microvascular endothelial cells, using a native collagen membrane as a scaffold. A successful pre-vascularization and dense formation of capillary-like structures at superficial areas was demonstrated. The lumen size of pre-formed blood vessels corresponded to the capillary size in vivo (10-30 μm). Comparing native with a highly cross-linked collagen membrane we found a distinct higher formation of capillary-like structures on the native membrane, apparently caused by higher secretion of angiogenic factors such as PDGF, IL-8 and angiopoietin by the cells. These capillary-like structures became functional blood vessels through anastomosis with the host vasculature after implantation in nude mice. This in vitro method should result in an accelerated blood supply to the biomaterial with cells after transplantation and increase the succes rates of the implant material. PMID:26606446

  8. How to prepare head tissue-equivalent liquids for SAR calculations, dosimetry and hyperthermia researches at 900 and 1800 MHz GSM frequencies.

    PubMed

    Sorgucu, Ugur; Develi, Ibrahim; Ozen, Sukru

    2016-03-01

    The potential harmful effect of electromagnetic fields on human health is an important issue that has been widely discussed in the scientific community. The investigation of temperature rise in human body following exposure to electromagnetic fields has been found impractical in many aspects. Therefore, fabrication of the tissue-equivalent liquids (TELs) is required. TELs have been widely employed in specific absorption rate calculations, dosimetry and hyperthermia researches. In this study, two separate head tissue-equivalent liquids (HELs) were prepared for 900 and 1800 MHz frequencies. The conductivity and relative permittivity of the HEL prepared for 900 MHz frequency were found to deviate from The Institute of Electrical and Electronics Engineers (IEEE) standards at the rates of 6.20 and 2.70 %, whereas the HEL prepared for 1800 MHz applications exhibited 1.83 and 3.22 % deviations from IEEE standards, respectively. This study provides a method for researchers to prepare their own HELs in a practical way. PMID:26116300

  9. A finite element solution for the anisotropic biphasic theory of tissue-equivalent mechanics: the effect of contact guidance on isometric cell traction measurement.

    PubMed

    Barocas, V H; Tranquillo, R T

    1997-08-01

    We present a method for solving the governing equations from our anisotropic biphasic theory of tissue-equivalent mechanics (Barocas and Tranquillo, 1997) for axisymmetric problems. A mixed finite element method is used for discretization of the spatial derivatives, and the DASPK subroutine (Brown et al., 1994) is used to solve the resulting differential-algebraic equation system. The preconditioned GMRES algorithm, using a preconditioner based on an extension of Dembo's (1994) adaptation of the Uzawa algorithm for viscous flows, provides an efficient and scaleable solution method, with the finite element method discretization being first-order accurate in space. In the cylindrical isometric cell traction assay, the chosen test problem, a cylindrical tissue equivalent is adherent at either end to fixed circular platens. As the cells exert traction on the collagen fibrils, the force required to maintain constant sample length, or load, is measured. However, radial compaction occurs during the course of the assay, so that the cell and network concentrations increase and collagen fibrils become aligned along the axis of the cylinder, leading to cell alignment along the axis. Our simulations predict that cell contact guidance leads to an increase in the load measured in the assay, but this effect is diminished by the tendency of contact guidance to inhibit radial compaction of the sample, which in turn reduces concentrations and hence the measured load. PMID:9285339

  10. Microbial colonization of an in vitro model of a tissue engineered human skin equivalent--a novel approach.

    PubMed

    Holland, Diana B; Bojar, Richard A; Jeremy, Anthony H T; Ingham, Eileen; Holland, Keith T

    2008-02-01

    This was a preliminary investigation to define the conditions of colonization of a human skin equivalent (SE) model with cutaneous microorganisms. SEs of 24 mm diameter were constructed with a dermal matrix of fibrin containing fibroblasts and a stratified epidermis. Microbial colonization of the SEs was carried out in a dry environment, comparable to 'in vivo' skin, using a blotting technique to remove inoculation fluid. The microbial communities were sampled by scrub washing and viable cells enumerated on selective growth medium. Staphylococcus epidermidis, Propionibacterium acnes and Malassezia furfur (human skin commensals) and Staphylococcus aureus (transient pathogen) were colonized at inoculum densities of 10(2)-10(6) CFU SE(-1) on the surface of replicate SEs. Growth of all species was supported for upto 72-120 h, with recovery densities of between 10(4)-10(9) CFU SE(-1). A novel, real-time growth monitoring method was also developed, using S. aureus containing a lux cassette. Light output increased from 20 to 95 h, and colonization increased from 10(2) to 10(8) CFU SE(-1), as confirmed by conventional recovery. Thus, the SE model has potential to investigate interactions between resident and transient microbial communities with themselves and their habitat, and for testing treatments to control pathogen colonization of human skin. PMID:18081841

  11. Development of a stable and reproducible tissue-equivalent phantom for use in infrared spectroscopy and imaging

    NASA Astrophysics Data System (ADS)

    Firbank, Michael; Hiraoka, Mutsuhisa; Delpy, David T.

    1993-09-01

    Much of the experimental work reported on the applications of near infrared spectroscopy and imaging for therapeutic purposes has been performed on multifarious tissue simulating materials, which often have unreproducible optical properties. To facilitate the quantitative testing of spectroscopy equipment, stable, reproducible phantoms which replicate the optical properties of tissue are needed. This paper describes one such phantom. The base material is a clear, non polymerized liquid polyester resin, which forms a solid on addition of a catalyst. The polyester has a low intrinsic absorption coefficient for infrared light and is nonscattering. Before the resin is set, measured quantities of scattering particle suspensions and absorbing dyes can be added. The scattering phase function of these particles has been measured, and the mean cosine of the scattering angle, g, calculated. Knowing this, by varying the concentration of scattering particles a range of materials with known transport scattering coefficients can be produced. By varying the concentration and mix of dyes, the absorption coefficient of the resin can be easily controlled. The resin can be easily machined or cast into arbitrary shapes, with regions of differing optical properties. Once set, the polyester is stable, in terms of both physical and optical properties.

  12. Study of microdosimetric energy deposition patterns in tissue-equivalent medium due to low-energy neutron fields using a graphite-walled proportional counter.

    PubMed

    Waker, A J; Aslam

    2011-06-01

    To improve radiation protection dosimetry for low-energy neutron fields encountered in nuclear power reactor environments, there is increasing interest in modeling neutron energy deposition in metrological instruments such as tissue-equivalent proportional counters (TEPCs). Along with these computational developments, there is also a need for experimental data with which to benchmark and test the results obtained from the modeling methods developed. The experimental work described in this paper is a study of the energy deposition in tissue-equivalent (TE) medium using an in-house built graphite-walled proportional counter (GPC) filled with TE gas. The GPC is a simple model of a standard TEPC because the response of the counter at these energies is almost entirely due to the neutron interactions in the sensitive volume of the counter. Energy deposition in tissue spheres of diameter 1, 2, 4 and 8 µm was measured in low-energy neutron fields below 500 keV. We have observed a continuously increasing trend in microdosimetric averages with an increase in neutron energy. The values of these averages decrease as we increase the simulated diameter at a given neutron energy. A similar trend for these microdosimetric averages has been observed for standard TEPCs and the Rossi-type, TE, spherical wall-less counter filled with propane-based TE gas in the same energy range. This implies that at the microdosimetric level, in the neutron energy range we employed in this study, the pattern of average energy deposited by starter and insider proton recoil events in the gas is similar to those generated cumulatively by crosser and stopper events originating from the counter wall plus starter and insider recoil events originating in the sensitive volume of a TEPC. PMID:21476858

  13. On the Applicability of the Thermal Dose Cumulative Equivalent Minutes Metric to the Denaturation of Bovine Serum Albumin in a Polyacrylamide Tissue Phantom

    SciTech Connect

    Nandlall, Sacha D.; Arora, Manish; Schiffter, Heiko A.; Coussios, Constantin-C.

    2009-04-14

    Thermal dose has been proposed for various hyperthermic cancer treatment modalities as a measure of heat-induced tissue damage. However, the applicability of current thermal dose metrics to tissue is not well understood, particularly at the temperatures and rates of heating relevant to ablative cancer therapy using High-Intensity Focussed Ultrasound (HIFU). In this work, we assess whether the most widely employed thermal dose metric, Cumulative Equivalent Minutes (CEM), can adequately quantify heat-induced denaturation in a tissue-mimicking material (phantom) consisting of Bovine Serum Albumin (BSA) proteins embedded in a polyacrylamide matrix. The phantom is exposed to various temperature profiles and imaged under controlled lighting conditions against a black background as it denatures and becomes progressively more opaque. Under the assumption that the mean backscattered luminous intensity provides a good measure of the extent of BSA denaturation, we establish a relationship between the amount of thermal damage caused to the phantom, exposure time, and temperature. We demonstrate that, for monotonically increasing and bounded temperature profiles, the maximal degree to which the phantom can denature is dependent on the peak temperature it reaches, irrespective of exposure duration. We also show that when the CEM is computed using the commonly employed piecewise-constant approximation of the parameter R, the CEM values corresponding to the same degree of damage delivered using different temperature profiles do not agree well with each other in general.

  14. Results on Dose Distributions in a Human Body from the Matroshka-R Experiment onboard the ISS Obtained with the Tissue-Equivalent Spherical Phantom

    NASA Astrophysics Data System (ADS)

    Shurshakov, Vyacheslav; Nikolaev, Igor; Kartsev, Ivan; Tolochek, Raisa; Lyagushin, Vladimir

    The tissue-equivalent spherical phantom (32 kg mass, 35 cm diameter and 10 cm central spherical cave) made in Russia has been used on board the ISS in Matroshka-R experiment for more than 10 years. Both passive and active space radiation detectors can be located inside the phantom and on its surface. Due to the specially chosen phantom shape and size, the chord length distributions of the detector locations are attributed to self-shielding properties of the critical organs in a human body. Originally the spherical phantom was installed in the star board crew cabin of the ISS Service Module, then in the Piers-1, MIM-2, and MIM-1 modules of the ISS Russian segment, and finally in JAXA Kibo module. Total duration of the detector exposure is more than 2000 days in 9 sessions of the space experiment. In the first phase of the experiment with the spherical phantom the dose measurements were realized with only passive detectors (thermoluminescent and solid state track detectors). The detectors are placed inside the phantom along the axes of 20 containers and on the phantom outer surface in 32 pockets of the phantom jacket. After each session the passive detectors are returned to the ground. The results obtained show the dose difference on the phantom surface as much as a factor of 2, the highest dose being usually observed close to the outer wall of the compartment, and the lowest dose being in the opposite location along the phantom diameter. However, because of the ISS module shielding properties an inverse dose distribution in a human body can be observed when the dose rate maximum is closer to the geometrical center of the module. Maximum dose rate measured in the phantom is obviously due to the action of two radiation sources, namely, galactic cosmic rays (GCR) and Earth’ radiation belts. Minimum dose rate is produced mainly by the strongly penetrating GCR particles and is mostly observed behind more than 5 g/cm2 tissue shielding. Critical organ doses, mean-tissue

  15. Monte Carlo Simulations on Neutron Transport and Absorbed Dose in Tissue-Equivalent Phantoms Exposed to High-Flux Epithermal Neutron Beams

    NASA Astrophysics Data System (ADS)

    Bartesaghi, G.; Gambarini, G.; Negri, A.; Carrara, M.; Burian, J.; Viererbl, L.

    2010-04-01

    Presently there are no standard protocols for dosimetry in neutron beams for boron neutron capture therapy (BNCT) treatments. Because of the high radiation intensity and of the presence at the same time of radiation components having different linear energy transfer and therefore different biological weighting factors, treatment planning in epithermal neutron fields for BNCT is usually performed by means of Monte Carlo calculations; experimental measurements are required in order to characterize the neutron source and to validate the treatment planning. In this work Monte Carlo simulations in two kinds of tissue-equivalent phantoms are described. The neutron transport has been studied, together with the distribution of the boron dose; simulation results are compared with data taken with Fricke gel dosimeters in form of layers, showing a good agreement.

  16. Wear particles derived from metal hip implants induce the generation of multinucleated giant cells in a 3-dimensional peripheral tissue-equivalent model.

    PubMed

    Dutta, Debargh K; Potnis, Pushya A; Rhodes, Kelly; Wood, Steven C

    2015-01-01

    Multinucleate giant cells (MGCs) are formed by the fusion of 5 to 15 monocytes or macrophages. MGCs can be generated by hip implants at the site where the metal surface of the device is in close contact with tissue. MGCs play a critical role in the inflammatory processes associated with adverse events such as aseptic loosening of the prosthetic joints and bone degeneration process called osteolysis. Upon interaction with metal wear particles, endothelial cells upregulate pro-inflammatory cytokines and other factors that enhance a localized immune response. However, the role of endothelial cells in the generation of MGCs has not been completely investigated. We developed a three-dimensional peripheral tissue-equivalent model (PTE) consisting of collagen gel, supporting a monolayer of endothelial cells and human peripheral blood mononuclear cells (PBMCs) on top, which mimics peripheral tissue under normal physiological conditions. The cultures were incubated for 14 days with Cobalt chromium alloy (CoCr ASTM F75, 1-5 micron) wear particles. PBMC were allowed to transit the endothelium and harvested cells were analyzed for MGC generation via flow cytometry. An increase in forward scatter (cell size) and in the propidium iodide (PI) uptake (DNA intercalating dye) was used to identify MGCs. Our results show that endothelial cells induce the generation of MGCs to a level 4 fold higher in 3-dimentional PTE system as compared to traditional 2-dimensional culture plates. Further characterization of MGCs showed upregulated expression of tartrate resistant alkaline phosphatase (TRAP) and dendritic cell specific transmembrane protein, (DC-STAMP), which are markers of bone degrading cells called osteoclasts. In sum, we have established a robust and relevant model to examine MGC and osteoclast formation in a tissue like environment using flow cytometry and RT-PCR. With endothelial cells help, we observed a consistent generation of metal wear particle- induced MGCs, which heralds

  17. Optimization of optical and mechanical properties of real architecture for 3-dimensional tissue equivalents: Towards treatment of limbal epithelial stem cell deficiency.

    PubMed

    Massie, Isobel; Kureshi, Alvena K; Schrader, Stefan; Shortt, Alex J; Daniels, Julie T

    2015-09-01

    Limbal epithelial stem cell (LESC) deficiency can cause blindness. Transplantation of cultured human limbal epithelial cells (hLE) on human amniotic membrane (HAM) can restore vision but clinical graft manufacture can be unreliable. We have developed a reliable and robust tissue equivalent (TE) alternative to HAM, Real Architecture for 3D Tissue (RAFT). Here, we aimed to optimize the optical and mechanical properties of RAFT TE for treatment of LESC deficiency in clinical application. The RAFT TE protocol is tunable; varying collagen concentration and volume produces differing RAFT TEs. These were compared with HAM samples taken from locations proximal and distal to the placental disc. Outcomes assessed were transparency, thickness, light transmission, tensile strength, ease of handling, degradation rates and suitability as substrate for hLE culture. Proximal HAM samples were thicker and stronger with poorer optical properties than distal HAM samples. RAFT TEs produced using higher amounts of collagen were thicker and stronger with poorer optical properties than those produced using lower amounts of collagen. The 'optimal' RAFT TE was thin, transparent but still handleable and was produced using 0.6ml of 3mg/ml collagen. Degradation rates of the 'optimal' RAFT TE and HAM were similar. hLE achieved confluency on 'optimal' RAFT TEs at comparable rates to HAM and cells expressed high levels of putative stem cell marker p63α. These findings support the use of RAFT TE for hLE transplantation towards treatment of LESC deficiency. PMID:26092352

  18. The response of a spherical tissue-equivalent proportional counter to 56-Fe particles from 200-1000 MeV/nucleon

    SciTech Connect

    Gersey, Bradford B.; Borak, Thomas B.; Guetersloh, Stephen B.; Zeitlin, Cary J.; Miller, J.; Heilbronn, L.; Murakami, T.; Iwata, Y.

    2001-09-04

    The radiation environment aboard the space shuttle and the International Space Station includes high-Z and high-energy (HZE) particles that are part of the galactic cosmic radiation (GCR) spectrum. Iron-56 is considered to be one of the most biologically important parts of the GCR spectrum. Tissue-equivalent proportional counters (TEPC) are used as active dosimeters on manned space flights. These TEPC's are further used to determine average quality factor for each space mission. A TEPC simulating a 1 micron diameter sphere of tissue was exposed as part of a particle spectrometer to iron-56 at energies from 200-1000 MeV/nucleon. The response of TEPC in terms of frequency-averaged lineal energy, dose-averaged lineal energy, as well as energy deposited at different impact parameters through detector was determined for six different incident energies of iron-56 in this energy range. Calculations determined that charged particle equilibrium was achieved for each of the six experiments. Energy depositions at different impact parameters were calculated using a radial dose distribution model and the results compared to experimental data.

  19. Studies on heavy charged particle interaction, water equivalence and Monte Carlo simulation in some gel dosimeters, water, human tissues and water phantoms

    NASA Astrophysics Data System (ADS)

    Kurudirek, Murat

    2015-09-01

    Some gel dosimeters, water, human tissues and water phantoms were investigated with respect to their radiological properties in the energy region 10 keV-10 MeV. The effective atomic numbers (Zeff) and electron densities (Ne) for some heavy charged particles such as protons, He ions, B ions and C ions have been calculated for the first time for Fricke, MAGIC, MAGAT, PAGAT, PRESAGE, water, adipose tissue, muscle skeletal (ICRP), muscle striated (ICRU), plastic water, WT1 and RW3 using mass stopping powers from SRIM Monte Carlo software. The ranges and straggling were also calculated for the given materials. Two different set of mass stopping powers were used to calculate Zeff for comparison. The water equivalence of the given materials was also determined based on the results obtained. The Monte Carlo simulation of the charged particle transport was also done using SRIM code. The heavy ion distribution along with its parameters were shown for the given materials for different heavy ions. Also the energy loss and damage events in water when irradiated with 100 keV heavy ions were studied in detail.

  20. SU-E-J-210: Characterizing Tissue Equivalent Materials for the Development of a Dual MRI-CT Heterogeneous Anthropomorphic Phantom Designed Specifically for MRI Guided Radiotherapy Systems

    SciTech Connect

    Steinmann, A; Stafford, R; Yung, J; Followill, D

    2015-06-15

    Purpose: MRI guided radiotherapy (MRIgRT) is an emerging technology which will eventually require a proficient quality auditing system. Due to different principles in which MR and CT acquire images, there is a need for a multi-imaging-modality, end-to-end QA phantom for MRIgRT. The purpose of this study is to identify lung, soft tissue, and tumor equivalent substitutes that share similar human-like CT and MR properties (i.e. Hounsfield units and relaxation times). Methods: Materials of interested such as common CT QA phantom materials, and other proprietary gels/silicones from Polytek, SmoothOn, and CompositeOne were first scanned on a GE 1.5T Signa HDxT MR. Materials that could be seen on both T1-weighted and T2-weighted images were then scanned on a GE Lightspeed RT16 CT simulator and a GE Discovery 750HD CT scanner and their HU values were then measured. The materials with matching HU values of lung (−500 to −700HU), muscle (+40HU) and soft tissue (+100 to +300HU) were further scanned on GE 1.5T Signa HDx to measure their T1 and T2 relaxation times from varying parameters of TI and TE. Results: Materials that could be visualized on T1-weighted and T2-weighted images from a 1.5T MR unit and had an appropriate average CT number, −650, −685, 46,169, and 168 HUs were: compressed cork saturated with water, Polytek Platsil™ Gel-00 combined with mini styrofoam balls, radiotherapy bolus material, SmoothOn Dragon-Skin™ and SmoothOn Ecoflex™, respectively. Conclusion: Post processing analysis is currently being performed to accurately map T1 and T2 values for each material tested. From previous MR visualization and CT examinations it is expected that Dragon-Skin™, Ecoflex™ and bolus will have values consistent with tissue and tumor substitutes. We also expect compressed cork statured with water, and Polytek™-styrofoam combination to have approximate T1 and T2 values suitable for lung-equivalent materials.

  1. Population and properties of superdeformed bands in A ~ 150 region

    NASA Astrophysics Data System (ADS)

    Zubov, A. S.; Sargsyan, V. V.; Adamian, G. G.; Antonenko, N. V.

    2013-04-01

    The production of superdeformed nuclei, treated as cluster configurations in the A ~ 150 region is described in the framework of statistical approach and the dinuclear system concept. The competition of particle emission from the dinuclear system and quasifission is taken into account. The calculated nuclear characteristics of the superdeformed band in 152Dy are close to the experimental values.

  2. Optimization of optical and mechanical properties of real architecture for 3-dimensional tissue equivalents: Towards treatment of limbal epithelial stem cell deficiency

    PubMed Central

    Massie, Isobel; Kureshi, Alvena K.; Schrader, Stefan; Shortt, Alex J.; Daniels, Julie T.

    2015-01-01

    Limbal epithelial stem cell (LESC) deficiency can cause blindness. Transplantation of cultured human limbal epithelial cells (hLE) on human amniotic membrane (HAM) can restore vision but clinical graft manufacture can be unreliable. We have developed a reliable and robust tissue equivalent (TE) alternative to HAM, Real Architecture for 3D Tissue (RAFT). Here, we aimed to optimize the optical and mechanical properties of RAFT TE for treatment of LESC deficiency in clinical application. The RAFT TE protocol is tunable; varying collagen concentration and volume produces differing RAFT TEs. These were compared with HAM samples taken from locations proximal and distal to the placental disc. Outcomes assessed were transparency, thickness, light transmission, tensile strength, ease of handling, degradation rates and suitability as substrate for hLE culture. Proximal HAM samples were thicker and stronger with poorer optical properties than distal HAM samples. RAFT TEs produced using higher amounts of collagen were thicker and stronger with poorer optical properties than those produced using lower amounts of collagen. The ‘optimal’ RAFT TE was thin, transparent but still handleable and was produced using 0.6 ml of 3 mg/ml collagen. Degradation rates of the ‘optimal’ RAFT TE and HAM were similar. hLE achieved confluency on ‘optimal’ RAFT TEs at comparable rates to HAM and cells expressed high levels of putative stem cell marker p63α. These findings support the use of RAFT TE for hLE transplantation towards treatment of LESC deficiency. PMID:26092352

  3. Measurement of the stochastic radial dose distribution for a 30-MeV proton beam using a wall-less tissue-equivalent proportional counter.

    PubMed

    Tsuda, S; Sato, T; Ogawa, T

    2016-02-01

    The frequency distribution of the lineal energy, y, of a 30-MeV proton beam was measured as a function of the radial distance from the beam path, and the dosed mean of [Formula: see text] was obtained to investigate the radial dependence of [Formula: see text] A wall-less tissue-equivalent proportional counter, in a cylindrical volume with simulated diameters of 0.36, 0.72 and 1.44 µm was used for the measurement of y distributions, yf(y). The measured values of yf(y) summed in the radial direction agreed fairly well with the corresponding data taken from the microdosimetric calculations using the PHITS code. The [Formula: see text] value of the 30-MeV proton beam presented its smallest value at r = 0.0 and gradually increased with radial distance, and the [Formula: see text] values of heavy ions such as iron showed rapid decrease with radial distance. This experimental result demonstrated that the stochastic deposited energy distribution of high-energy protons in the microscopic region is rather constant in the core as well as in the penumbra region of the track structure. PMID:25956785

  4. Effect of Tissue Composition on Dose Distribution in Electron Beam Radiotherapy

    PubMed Central

    Ghorbani, M.; Tabatabaei, Z. S.; Vejdani Noghreiyan, A.; Vosoughi, H.; Knaup, C.

    2015-01-01

    Objective The aim of this study is to evaluate the effect of tissue composition on dose distribution in electron beam radiotherapy. Methods A Siemens Primus linear accelerator and a phantom were simulated using MCNPX Monte Carlo code. In a homogeneous cylindrical phantom, six types of soft tissue and three types of tissue-equivalent materials were investigated. The tissues included muscle (skeletal), adipose tissue, blood (whole), breast tissue, soft tissue (9-components) and soft tissue (4-component). The tissue-equivalent materials were water, A-150 tissue-equivalent plastic and perspex. Electron dose relative to dose in 9-component soft tissue at various depths on the beam’s central axis was determined for 8, 12, and 14 MeV electron energies. Results The results of relative electron dose in various materials relative to dose in 9-component soft tissue were reported for 8, 12 and 14 MeV electron beams as tabulated data. While differences were observed between dose distributions in various soft tissues and tissue-equivalent materials, which vary with the composition of material, electron energy and depth in phantom, they can be ignored due to the incorporated uncertainties in Monte Carlo calculations. Conclusion Based on the calculations performed, differences in dose distributions in various soft tissues and tissue-equivalent materials are not significant. However, due to the difference in composition of various materials, further research in this field with lower uncertainties is recommended. PMID:25973407

  5. Characterization of MOSFET dosimeter angular dependence in three rotational axes measured free-in-air and in soft-tissue equivalent material

    PubMed Central

    Koivisto, Juha; Kiljunen, Timo; Wolff, Jan; Kortesniemi, Mika

    2013-01-01

    When performing dose measurements on an X-ray device with multiple angles of irradiation, it is necessary to take the angular dependence of metal-oxide-semiconductor field-effect transistor (MOSFET) dosimeters into account. The objective of this study was to investigate the angular sensitivity dependence of MOSFET dosimeters in three rotational axes measured free-in-air and in soft-tissue equivalent material using dental photon energy. Free-in-air dose measurements were performed with three MOSFET dosimeters attached to a carbon fibre holder. Soft tissue measurements were performed with three MOSFET dosimeters placed in a polymethylmethacrylate (PMMA) phantom. All measurements were made in the isocenter of a dental cone-beam computed tomography (CBCT) scanner using 5º angular increments in the three rotational axes: axial, normal-to-axial and tangent-to-axial. The measurements were referenced to a RADCAL 1015 dosimeter. The angular sensitivity free-in-air (1 SD) was 3.7 ± 0.5 mV/mGy for axial, 3.8 ± 0.6 mV/mGy for normal-to-axial and 3.6 ± 0.6 mV/mGy for tangent-to-axial rotation. The angular sensitivity in the PMMA phantom was 3.1 ± 0.1 mV/mGy for axial, 3.3 ± 0.2 mV/mGy for normal-to-axial and 3.4 ± 0.2 mV/mGy for tangent-to-axial rotation. The angular sensitivity variations are considerably smaller in PMMA due to the smoothing effect of the scattered radiation. The largest decreases from the isotropic response were observed free-in-air at 90° (distal tip) and 270° (wire base) in the normal-to-axial and tangent-to-axial rotations, respectively. MOSFET dosimeters provide us with a versatile dosimetric method for dental radiology. However, due to the observed variation in angular sensitivity, MOSFET dosimeters should always be calibrated in the actual clinical settings for the beam geometry and angular range of the CBCT exposure. PMID:23520268

  6. Characterization of MOSFET dosimeter angular dependence in three rotational axes measured free-in-air and in soft-tissue equivalent material.

    PubMed

    Koivisto, Juha; Kiljunen, Timo; Wolff, Jan; Kortesniemi, Mika

    2013-09-01

    When performing dose measurements on an X-ray device with multiple angles of irradiation, it is necessary to take the angular dependence of metal-oxide-semiconductor field-effect transistor (MOSFET) dosimeters into account. The objective of this study was to investigate the angular sensitivity dependence of MOSFET dosimeters in three rotational axes measured free-in-air and in soft-tissue equivalent material using dental photon energy. Free-in-air dose measurements were performed with three MOSFET dosimeters attached to a carbon fibre holder. Soft tissue measurements were performed with three MOSFET dosimeters placed in a polymethylmethacrylate (PMMA) phantom. All measurements were made in the isocenter of a dental cone-beam computed tomography (CBCT) scanner using 5º angular increments in the three rotational axes: axial, normal-to-axial and tangent-to-axial. The measurements were referenced to a RADCAL 1015 dosimeter. The angular sensitivity free-in-air (1 SD) was 3.7 ± 0.5 mV/mGy for axial, 3.8 ± 0.6 mV/mGy for normal-to-axial and 3.6 ± 0.6 mV/mGy for tangent-to-axial rotation. The angular sensitivity in the PMMA phantom was 3.1 ± 0.1 mV/mGy for axial, 3.3 ± 0.2 mV/mGy for normal-to-axial and 3.4 ± 0.2 mV/mGy for tangent-to-axial rotation. The angular sensitivity variations are considerably smaller in PMMA due to the smoothing effect of the scattered radiation. The largest decreases from the isotropic response were observed free-in-air at 90° (distal tip) and 270° (wire base) in the normal-to-axial and tangent-to-axial rotations, respectively. MOSFET dosimeters provide us with a versatile dosimetric method for dental radiology. However, due to the observed variation in angular sensitivity, MOSFET dosimeters should always be calibrated in the actual clinical settings for the beam geometry and angular range of the CBCT exposure. PMID:23520268

  7. Establishing Substantial Equivalence: Transcriptomics

    NASA Astrophysics Data System (ADS)

    Baudo, María Marcela; Powers, Stephen J.; Mitchell, Rowan A. C.; Shewry, Peter R.

    Regulatory authorities in Western Europe require transgenic crops to be substantially equivalent to conventionally bred forms if they are to be approved for commercial production. One way to establish substantial equivalence is to compare the transcript profiles of developing grain and other tissues of transgenic and conventionally bred lines, in order to identify any unintended effects of the transformation process. We present detailed protocols for transcriptomic comparisons of developing wheat grain and leaf material, and illustrate their use by reference to our own studies of lines transformed to express additional gluten protein genes controlled by their own endosperm-specific promoters. The results show that the transgenes present in these lines (which included those encoding marker genes) did not have any significant unpredicted effects on the expression of endogenous genes and that the transgenic plants were therefore substantially equivalent to the corresponding parental lines.

  8. Microscopic study of superdeformation in the A = 150 mass region

    SciTech Connect

    Rigollet, C.; Gall, B.; Bonche, P.

    1996-12-31

    The authors are presently investigating the properties of superdeformed (SD) nuclear states in the A=150 mass region. For that purpose, they use the cranked HFB method in which pairing correlations are treated dynamically by means of the Lipkin-Nogami prescription. Their goal is to take advantage of the large amount of experimental data to test the predictive power of their microscopic approach and of the effective interaction. In the present communication, they focus on {sup 152}Dy and {sup 153}Dy for which there are recent experimental data. In particular lifetime measurements have allowed to extract electric quadrupole moments. The new Skyrme effective force SLy4 is used to describe the nucleon-nucleon interaction, while for the pairing channel the authors use a density-dependent zero-range interaction.

  9. Performance of a 150-MW S-band klystron

    SciTech Connect

    Sprehn, D.; Phillips, R.M.; Caryotakis, G.

    1994-09-01

    As part of an international collaboration, the Stanford Linear Accelerator Center (SLAC) klystron group has designed, fabricated, and tested a 60-Hz, 3-{mu}s, 150-MW S-band klystron built for Deutsches Elektronen Synchrotron (DESY). A test diode with a 535-kV, 700-A electron beam was constructed to verify the gun operation. The first klystron was built and successfully met design specifications. The 375-MW electron beam represents a new record for SLAC accelerator klystrons in terms of voltage, current, energy, and ruggedness of design. The rf output power is a 150% increase over the S-band tubes currently used in the two-mile-long linear accelerator at SLAC. This paper discusses design issues and experimental results of the diode and klystron.

  10. Simultaneous determination of equivalent dose to organs and tissues of the patient and of the physician in interventional radiology using the Monte Carlo method

    NASA Astrophysics Data System (ADS)

    Bozkurt, A.; Bor, D.

    2007-01-01

    This study presents the results of computations of organ equivalent doses and effective doses for the patient and the primary physician during an interventional cardiological examination. The simulations were carried out for seven x-ray spectra (between 60 kVp and 120 kVp) using the Monte Carlo code MCNP. The voxel-based whole-body model VIP-Man was employed to represent both the patient and the physician, the former lying on the operation table while the latter standing 15 cm from the patient at about waist level behind a lead apron. The x-rays, which were generated by a point source positioned around the table and were directed with a conical distribution, irradiated the patient's heart under five major projections used in a coronary angiography examination. The mean effective doses under LAO45, PA, RAO30, LAO45/CAUD30 and LLAT irradiation conditions were calculated as 0.092, 0.163, 0.161, 0.133 and 0.118 mSv/(Gy cm2) for the patient and 1.153, 0.159, 0.145, 0.164 and 0.027 μSv/(Gy cm2) for the shielded physician. The effective doses for the patient determined in this study were usually lower than the literature data obtained through measurements and/or calculations and the discrepancies could be attributed to the fact that this study computes the effective doses specific to the VIP-Man body model, which lacks an ovarian contribution to the gonadal equivalent dose. The effective doses for the physician agreed reasonably well with the literature data.

  11. Plutonium 239 Equivalency Calculations

    SciTech Connect

    Wen, J

    2011-05-31

    This document provides the basis for converting actual weapons grade plutonium mass to a plutonium equivalency (PuE) mass of Plutonium 239. The conversion can be accomplished by performing calculations utilizing either: (1) Isotopic conversions factors (CF{sub isotope}), or (2) 30-year-old weapons grade conversion factor (CF{sub 30 yr}) Both of these methods are provided in this document. Material mass and isotopic data are needed to calculate PuE using the isotopic conversion factors, which will provide the actual PuE value at the time of calculation. PuE is the summation of the isotopic masses times their associated isotopic conversion factors for plutonium 239. Isotopic conversion factors are calculated by a normalized equation, relative to Plutonium 239, of specific activity (SA) and cumulated dose inhalation affects based on 50-yr committed effective dose equivalent (CEDE). The isotopic conversion factors for converting weapons grade plutonium to PuE are provided in Table-1. The unit for specific activity (SA) is curies per gram (Ci/g) and the isotopic SA values come from reference [1]. The cumulated dose inhalation effect values in units of rem/Ci are based on 50-yr committed effective dose equivalent (CEDE). A person irradiated by gamma radiation outside the body will receive a dose only during the period of irradiation. However, following an intake by inhalation, some radionuclides persist in the body and irradiate the various tissues for many years. There are three groups CEDE data representing lengths of time of 0.5 (D), 50 (W) and 500 (Y) days, which are in reference [2]. The CEDE values in the (W) group demonstrates the highest dose equivalent value; therefore they are used for the calculation.

  12. Photon and neutron dose discrimination using low pressure proportional counters with graphite and A150 walls.

    PubMed

    Kyllönen, J; Lindborg, L

    2007-01-01

    A graphite-walled proportional counter with low neutron sensitivity was used in combination with a tissue-equivalent proportional counter (TEPC) to separate the photon and neutron components in mixed radiation fields. Monte Carlo (MCNP4C) simulations of the photon and neutron responses of the two detectors were done to obtain correction factors for the sensitivity differences. In an alternative method the radiation components were determined using constant-yD-values for typical photon and neutron energy distributions. The results show no significant difference between the two methods and the measured neutron dose-equivalent agrees within +/-50% with Bonner sphere determined values. The experimental data were obtained in measurement campaigns organised within the EVIDOS-project. PMID:17309871

  13. Comparisons of LET Distributions for Protons with Energies between50 and 200 MeV Determined Using a Spherical Tissue-EquivalentProportional Counter (TEPC) and a Position-Sensitive Silicon Spectrometer(RRMD-III)

    SciTech Connect

    Borak, Thomas B.; Doke, Tadayoshi; Fuse, T.; Guetersloh, StephenB.; Heilbronn, Lawrence H.; Hara, K.; Moyers, Michael; Suzuki, S.; Taddei, Phillip; Terasawa, K.; Zeitlin, Cary J.

    2004-12-01

    Experiments have been performed to measure the response of a spherical tissue-equivalent proportional counter (TEPC) and a silicon-based LET spectrometer (RRMD-III) to protons with energies ranging from 50 200 MeV. This represents a large portion of the energy distribution for trapped protons encountered by astronauts in low-Earth orbit. The beam energies were obtained using plastic polycarbonate degraders with a monoenergetic beam that was extracted from a proton synchrotron. The LET spectrometer provided excellent agreement with the expected LET distribution emerging from the energy degraders. The TEPC cannot measure the LET distribution directly. However, the frequency mean value of lineal energy, y bar f, provided a good approximation to LET. This is in contrast to previous results for high-energy heavy ions wherey barf underestimated LET, whereas the dose-averaged lineal energy, y barD, provided a good approximation to LET.

  14. Equivalence principles and electromagnetism

    NASA Technical Reports Server (NTRS)

    Ni, W.-T.

    1977-01-01

    The implications of the weak equivalence principles are investigated in detail for electromagnetic systems in a general framework. In particular, it is shown that the universality of free-fall trajectories (Galileo weak equivalence principle) does not imply the validity of the Einstein equivalence principle. However, the Galileo principle plus the universality of free-fall rotation states does imply the Einstein principle.

  15. PATHOGEN EQUIVALENCY COMMITTEE UPDATE: PFRP EQUIVALENCY DETERMINATIONS

    EPA Science Inventory

    This presentation will:

    Review the mandate of the Pathogen Equivalency Committee
    Review the PEC's current membership of 10
    Discuss how a typical application is evaluated
    Note where information can be found
    List present deliberations/applications and describe t...

  16. Equivalence of Dirac formulations

    NASA Astrophysics Data System (ADS)

    Joyce, William P.; Martin, Jeremy G.

    2002-06-01

    We construct general Dirac theories in both ⊗ ℓ(3, 1) and ⊗ ℓ(1, 3) using a first order left acting Dirac operator. Any two such theories are equivalent provided they have the same dimension. We also show that every 16- or 8-dimensional real Dirac theory in ℓ(3, 1) is equivalent to some (complex) Dirac theory in ⊗ ℓ(1, 3). As an immediate consequence of this we have that the Hestenes and original Dirac formulations are equivalent.

  17. Helical Tomotherapy vs. Intensity-Modulated Proton Therapy for Whole Pelvis Irradiation in High-Risk Prostate Cancer Patients: Dosimetric, Normal Tissue Complication Probability, and Generalized Equivalent Uniform Dose Analysis

    SciTech Connect

    Widesott, Lamberto; Pierelli, Alessio; Fiorino, Claudio; Lomax, Antony J.; Amichetti, Maurizio; Cozzarini, Cesare; Soukup, Martin; Schneider, Ralf; Hug, Eugen; Di Muzio, Nadia; Calandrino, Riccardo; Schwarz, Marco

    2011-08-01

    Purpose: To compare intensity-modulated proton therapy (IMPT) and helical tomotherapy (HT) treatment plans for high-risk prostate cancer (HRPCa) patients. Methods and Materials: The plans of 8 patients with HRPCa treated with HT were compared with IMPT plans with two quasilateral fields set up (-100{sup o}; 100{sup o}) and optimized with the Hyperion treatment planning system. Both techniques were optimized to simultaneously deliver 74.2 Gy/Gy relative biologic effectiveness (RBE) in 28 fractions on planning target volumes (PTVs)3-4 (P + proximal seminal vesicles), 65.5 Gy/Gy(RBE) on PTV2 (distal seminal vesicles and rectum/prostate overlapping), and 51.8 Gy/Gy(RBE) to PTV1 (pelvic lymph nodes). Normal tissue calculation probability (NTCP) calculations were performed for the rectum, and generalized equivalent uniform dose (gEUD) was estimated for the bowel cavity, penile bulb and bladder. Results: A slightly better PTV coverage and homogeneity of target dose distribution with IMPT was found: the percentage of PTV volume receiving {>=}95% of the prescribed dose (V{sub 95%}) was on average >97% in HT and >99% in IMPT. The conformity indexes were significantly lower for protons than for photons, and there was a statistically significant reduction of the IMPT dosimetric parameters, up to 50 Gy/Gy(RBE) for the rectum and bowel and 60 Gy/Gy(RBE) for the bladder. The NTCP values for the rectum were higher in HT for all the sets of parameters, but the gain was small and in only a few cases statistically significant. Conclusions: Comparable PTV coverage was observed. Based on NTCP calculation, IMPT is expected to allow a small reduction in rectal toxicity, and a significant dosimetric gain with IMPT, both in medium-dose and in low-dose range in all OARs, was observed.

  18. ETV Report: Siemens Model V-40R-A150 Open Channel UV System

    EPA Science Inventory

    Verification testing of the Siemens Barrier Sunlight V-40R-A150 UV System was completed at the UV Validation and Research Center of New York (UV Center), located in Johnstown, NY. The V-40R System supplied by Siemens utilizes 40 high-output, low-pressure amalgam lamps, oriented ...

  19. Equivalent Neutral Wind

    NASA Technical Reports Server (NTRS)

    Liu, W. Timothy; Tang, Wenqing

    1996-01-01

    The definition of equivalent neutral wind and the rationale for using it as the geophysical product of a spaceborne scatterometer are reviewed. The differences between equivalent neutral wind and actual wind, which are caused by atmospheric density stratification, are demonstrated with measurements at selected locations. A method of computing this parameter from ship and buoy measurements is described and some common fallacies in accounting for the effects of atmospheric stratification on wind shear are discussed. The computer code for the model to derive equivalent neutral wind is provided.

  20. Neutron dose equivalent meter

    DOEpatents

    Olsher, Richard H.; Hsu, Hsiao-Hua; Casson, William H.; Vasilik, Dennis G.; Kleck, Jeffrey H.; Beverding, Anthony

    1996-01-01

    A neutron dose equivalent detector for measuring neutron dose capable of accurately responding to neutron energies according to published fluence to dose curves. The neutron dose equivalent meter has an inner sphere of polyethylene, with a middle shell overlying the inner sphere, the middle shell comprising RTV.RTM. silicone (organosiloxane) loaded with boron. An outer shell overlies the middle shell and comprises polyethylene loaded with tungsten. The neutron dose equivalent meter defines a channel through the outer shell, the middle shell, and the inner sphere for accepting a neutron counter tube. The outer shell is loaded with tungsten to provide neutron generation, increasing the neutron dose equivalent meter's response sensitivity above 8 MeV.

  1. X-ray phase contrast imaging of the breast: Analysis of tissue simulating materials

    SciTech Connect

    Vedantham, Srinivasan; Karellas, Andrew

    2013-04-15

    that of adipose tissue, the tissue-equivalent material better approximated the adipose tissue in terms of {mu}. Polymethyl methacrylate, a commonly used tissue substitute, exhibited {delta} greater than fibroglandular tissue by {approx}12%. The A-150 plastic closely approximated the skin. Several materials exhibited {delta} between that of adipose and fibroglandular tissue. However, there was an energy-dependent mismatch in terms of equivalent fibroglandular weight fraction between {delta} and {mu} for these materials. For microcalcifications, aluminum and calcium carbonate were observed to straddle the {delta} and {mu} of calcium oxalate and calcium hydroxyapatite. Aluminum oxide, commonly used to represent microcalcifications in the American College of Radiology recommended phantoms for accreditation exhibited {delta} greater than calcium hydroxyapatite by {approx}23%. Conclusions: A breast phantom comprising A-150 plastic to represent the skin, commercially available adipose and fibroglandular tissue-equivalent formulations to represent adipose and fibroglandular tissue, respectively, was found to be best suited for x-ray phase-sensitive imaging of the breast. Calcium carbonate or aluminum can be used to represent microcalcifications.

  2. The Interaction Equivalency Theorem

    ERIC Educational Resources Information Center

    Miyazoe, Terumi; Anderson, Terry

    2010-01-01

    This paper examines the key issues regarding The Interaction Equivalency Theorem posited by Anderson (2003a), which consists of the three interaction elements found in formal education courses among teacher, student, and content. It first examines the core concepts of the theorem and argues that two theses of different dimensions can be…

  3. PATHOGEN EQUIVALENCY COMMITTEE (PEC)

    EPA Science Inventory

    The U.S. Environmental Protection Agency created the PEC in 1985 to make recommendations to EPA and State managers on the equivalency of unproven sewage sludge disinfection technologies/processes to either a Process to Significantly Reduce Pathogens (PSRP) or a Process to Further...

  4. Equivalent Colorings with "Maple"

    ERIC Educational Resources Information Center

    Cecil, David R.; Wang, Rongdong

    2005-01-01

    Many counting problems can be modeled as "colorings" and solved by considering symmetries and Polya's cycle index polynomial. This paper presents a "Maple 7" program link http://users.tamuk.edu/kfdrc00/ that, given Polya's cycle index polynomial, determines all possible associated colorings and their partitioning into equivalence classes. These…

  5. Five Equivalent d Orbitals

    ERIC Educational Resources Information Center

    Pauling, Linus; McClure, Vance

    1970-01-01

    Amplifies and clarifies a previous paper on pyramidal d orbitals. Discusses two sets of pyramid d orbitals with respect to their maximum bond strength and their symmetry. Authors described the oblate and prolate pentagonal antiprisms arising from the two sets of five equivalent d orbitals. (RR)

  6. Construction of a 150 t/d pilot plant for bituminous coal liquefaction

    SciTech Connect

    Ishibashi, Hirohito; Kobayashi, Masatoshi; Suzuki, Satoru

    1994-12-31

    This present paper covers bituminous coal liquefaction R and D carried out by Nippon Coal Oil Co., Ltd. (NCOL). Construction of a 150 ton/day bituminous coal liquefaction pilot plant will be presented. The NEDOL process is characterized by the wide applicability of various coal grades, such as low-rank bituminous coal, subbituminous coal and low-rank subbituminous coal, and a single-stage liquefaction method that combines the advantages of a hydrogen-donor solvent and a fine iron catalyst. A vacuum distillation system for solid-liquid separation is used to improve reliability. The simplicity of this process ensures a high degree of stability.

  7. Establishing Substantial Equivalence: Metabolomics

    NASA Astrophysics Data System (ADS)

    Beale, Michael H.; Ward, Jane L.; Baker, John M.

    Modern ‘metabolomic’ methods allow us to compare levels of many structurally diverse compounds in an automated fashion across a large number of samples. This technology is ideally suited to screening of populations of plants, including trials where the aim is the determination of unintended effects introduced by GM. A number of metabolomic methods have been devised for the determination of substantial equivalence. We have developed a methodology, using [1H]-NMR fingerprinting, for metabolomic screening of plants and have applied it to the study of substantial equivalence of field-grown GM wheat. We describe here the principles and detail of that protocol as applied to the analysis of flour generated from field plots of wheat. Particular emphasis is given to the downstream data processing and comparison of spectra by multivariate analysis, from which conclusions regarding metabolome changes due to the GM can be assessed against the background of natural variation due to environment.

  8. Tissue Tregs.

    PubMed

    Panduro, Marisella; Benoist, Christophe; Mathis, Diane

    2016-05-20

    The immune system is responsible for defending an organism against the myriad of microbial invaders it constantly confronts. It has become increasingly clear that the immune system has a second major function: the maintenance of organismal homeostasis. Foxp3(+)CD4(+) regulatory T cells (Tregs) are important contributors to both of these critical activities, defense being the primary purview of Tregs circulating through lymphoid organs, and homeostasis ensured mainly by their counterparts residing in parenchymal tissues. This review focuses on so-called tissue Tregs. We first survey existing information on the phenotype, function, sustaining factors, and human equivalents of the three best-characterized tissue-Treg populations-those operating in visceral adipose tissue, skeletal muscle, and the colonic lamina propria. We then attempt to distill general principles from this body of work-as concerns the provenance, local adaptation, molecular sustenance, and targets of action of tissue Tregs, in particular. PMID:27168246

  9. Comments on TNT Equivalence

    SciTech Connect

    Cooper, P.W.

    1994-07-01

    The term ``TNT Equivalence`` is used throughout the explosives and related industries to compare the effects of the output of a given explosive to that of TNT. This is done for technical design reasons in scaling calculation such as for the prediction of blast waves, craters, and structural response, and is also used as a basis for government regulations controlling the shipping, handling and storage of explosive materials, as well as for the siting and design of explosive facilities. TNT equivalence is determined experimentally by several different types of tests, the most common of which include: plate dent, ballistic mortar, trauzl, sand crush, and air blast. All of these tests do not necessarily measure the same output property of the sample explosive. As examples of this, some tests depend simply upon the CJ pressure, some depend upon the PV work in the CJ zone and in the Taylor wave behind the CJ plane, some are functions of the total work which includes that from secondary combustion in the air mixing region of the fireball and are acutely effected by the shape of the pressure-time profile of the wave. Some of the tests incorporate systematic errors which are not readily apparent, and which have a profound effect upon skewing the resultant data. Further, some of the tests produce different TNT Equivalents for the same explosive which are a function of the conditions at which the test is run. This paper describes the various tests used, discusses the results of each test and makes detailed commentary on what the test is actually measuring, how the results may be interpreted, and if and how these results can be predicted by first principals based calculations. Extensive data bases are referred to throughout the paper and used in examples for each point in the commentaries.

  10. A 150 and 300 kW lightweight diesel aircraft engine design study

    NASA Technical Reports Server (NTRS)

    Brouwers, A. P.

    1980-01-01

    The diesel engine was reinvestigated as an aircraft powerplant through design study conducted to arrive at engine configurations and applicable advanced technologies. Two engines are discussed, a 300 kW six-cylinder engine for twin engine general aviation aircraft and a 150 kW four-cylinder engine for single engine aircraft. Descriptions of each engine include concept drawings, a performance analysis, stress and weight data, and a cost study. This information was used to develop two airplane concepts, a six-place twin and a four-place single engine aircraft. The aircraft study consists of installation drawings, computer generated performance data, aircraft operating costs, and drawings of the resulting airplanes. The performance data show a vast improvement over current gasoline-powered aircraft.

  11. Local unitary equivalence of quantum states and simultaneous orthogonal equivalence

    NASA Astrophysics Data System (ADS)

    Jing, Naihuan; Yang, Min; Zhao, Hui

    2016-06-01

    The correspondence between local unitary equivalence of bipartite quantum states and simultaneous orthogonal equivalence is thoroughly investigated and strengthened. It is proved that local unitary equivalence can be studied through simultaneous similarity under projective orthogonal transformations, and four parametrization independent algorithms are proposed to judge when two density matrices on ℂd1 ⊗ ℂd2 are locally unitary equivalent in connection with trace identities, Kronecker pencils, Albert determinants and Smith normal forms.

  12. Waste Determination Equivalency - 12172

    SciTech Connect

    Freeman, Rebecca D.

    2012-07-01

    Secretary of Energy in January of 2006 based on proposed processing techniques with the expectation that it could be revised as new processing capabilities became viable. Once signed, however, it became evident that any changes would require lengthy review and another determination signed by the Secretary of Energy. With the maturation of additional salt removal technologies and the extension of the SWPF start-up date, it becomes necessary to define 'equivalency' to the processes laid out in the original determination. For the purposes of SRS, any waste not processed through Interim Salt Processing must be processed through SWPF or an equivalent process, and therefore a clear statement of the requirements for a process to be equivalent to SWPF becomes necessary. (authors)

  13. Establishing Substantial Equivalence: Proteomics

    NASA Astrophysics Data System (ADS)

    Lovegrove, Alison; Salt, Louise; Shewry, Peter R.

    Wheat is a major crop in world agriculture and is consumed after processing into a range of food products. It is therefore of great importance to determine the consequences (intended and unintended) of transgenesis in wheat and whether genetically modified lines are substantially equivalent to those produced by conventional plant breeding. Proteomic analysis is one of several approaches which can be used to address these questions. Two-dimensional PAGE (2D PAGE) remains the most widely available method for proteomic analysis, but is notoriously difficult to reproduce between laboratories. We therefore describe methods which have been developed as standard operating procedures in our laboratory to ensure the reproducibility of proteomic analyses of wheat using 2D PAGE analysis of grain proteins.

  14. Design assessment of a 150 kWt CFBC Test Unit

    SciTech Connect

    Batu, A.; Selcuk, N.; Kulah, G.

    2010-04-15

    For clean and efficient energy generation from coal, the most suitable technology known to date is 'Fluidized Bed Combustion' technology. Applications of circulating fluidized bed (CFB) combustion technology have been steadily increasing in both capacity and number over the past decade. Designs of these units have been based on the combustion tests carried out in pilot scale facilities to determine the combustion and desulfurization characteristics of coal and limestone reserves in CFB conditions. Similarly, utilization of Turkish lignites in CFB boilers necessitates adaptation of CFB combustion technology to these resources. However, the design of these test units are not based on firing coals with high ash, volatile matter and sulfur contents like Turkish lignites. For this purpose, a 150 kWt CFB combustor test unit is designed and constructed in Chemical Engineering Department of Middle East Technical University, based on the extensive experience acquired at the existing 0.3 MWt Bubbling Atmospheric Fluidized Bed Combustor (AFBC) Test Rig. Following the commissioning tests, a combustion test is carried out for investigation of combustion characteristics of Can lignite in CFB conditions and for assessment of the design of test unit. Comparison of the design outputs with experimental results reveals that most of the predictions and assumptions have acceptable agreement with the operating conditions. In conclusion, the performance of 150 kWt CFBC Test Unit is found to be satisfactory to be utilized for the long term research studies on combustion and desulfurization characteristics of indigenous lignite reserves in circulating fluidized bed combustors. (author)

  15. Structural Design and Analysis of a 150 kJ HTS SMES Cryogenic System

    NASA Astrophysics Data System (ADS)

    Han, Peng; Wu, Yu; Liu, Huajun; Li, Laifeng; Yang, Huihui

    A 150 kJ high temperature superconducting magnetic energy storage (HTS-SMES) system is under manufacturing in China. This paper focuses on the structural design and analysis of the SMES cryogenic system. The cryogenic system is designed and fabricated to maintain the working temperature. The system includes a vacuum vessel, its thermal radiation shield, its supporting devices, conduction plates, and current leads. Two G-M cryocoolers are used for the system cooling, the main one is connected to the HTS coils and the other is connected to the thermal shield and the lower ends of the current leads. In this study, the 3D models of the SMES cryogenic system were created with CATIA, a 3D model design software, and the analysis of the SMES cryogenic system was done by ANSYS. The mechanical analysis results on the vacuum vessel, suspension devices and supporting devices are presented, particularly the analyses on suspenders and shelf supports are of vital importance since the finished SMES system should meet vehicle-mounted requirements in long time transport. The heat load and the temperature distribution of the thermal shield were analyzed. A cooling experiment of the cryogenic system was made and the thermal shield was cooled down to about 50 K.

  16. Equivalence of superspace groups

    PubMed Central

    van Smaalen, Sander; Campbell, Branton J.; Stokes, Harold T.

    2013-01-01

    An algorithm is presented which determines the equivalence of two settings of a (3 + d)-dimensional superspace group (d = 1, 2, 3). The algorithm has been implemented as a web tool on , providing the transformation of any user-given superspace group to the standard setting of this superspace group in . It is shown how the standard setting of a superspace group can be directly obtained by an appropriate transformation of the external-space lattice vectors (the basic structure unit cell) and a transformation of the internal-space lattice vectors (new modulation wavevectors are linear combinations of old modulation wavevectors plus a three-dimensional reciprocal-lattice vector). The need for non-standard settings in some cases and the desirability of employing standard settings of superspace groups in other cases are illustrated by an analysis of the symmetries of a series of compounds, comparing published and standard settings and the transformations between them. A compilation is provided of standard settings of compounds with two- and three-dimensional modulations. The problem of settings of superspace groups is discussed for incommensurate composite crystals and for chiral superspace groups. PMID:23250064

  17. A 150-year variation of the Kuroshio transport inferred from coral nitrogen isotope signature

    NASA Astrophysics Data System (ADS)

    Yamazaki, Atsuko; Watanabe, Tsuyoshi; Tsunogai, Urumu; Iwase, Fumihito; Yamano, Hiroya

    2016-06-01

    The Kuroshio Current is a major global ocean current that drives the physical ocean-atmosphere system with heat transport from tropical to temperate zones in the North Pacific Ocean. We reconstructed the variability of the Kuroshio transport over the past 150 years using coral skeletal nitrogen isotopic composition (δ15Ncoral). A 150 year δ15Ncoral record (1859-2008 A.D.) is 4 times the length of the observational record (1971 to present) and could provide a direct comparison with global climate change, such as the Pacific Decadal Oscillation (PDO) index and El-Niño-Southern Oscillation (ENSO), through recent global warming. Coral cores from Porites were collected from Tatsukushi Bay in 2008 on the Pacific coast of Japan, which is located on the northern front of the Kuroshio Current. δ15Ncoral was used as a proxy to record the δ15N of nitrate (δ15Nnitrate) controlled by the upwelling of subtropical subsurface water (δ15Nnitrate; ~ +2 - +3‰), and δ15Ncoral was negatively correlated with observations of the Kuroshio transport (R = -0.69, P < 0.001) and the 2 year lagged PDO index (R = -0.63, P < 0.005) from 1972 to 2007. The 150 year record of δ15Ncoral suggested that the Kuroshio transport varied with ~25 year cycle, and the amplitude became more stable, and the volume was intensified through the twentieth century. The Kuroshio transport was intensified by the La Niña state in the early 1900s and by the El Niño-PDO state after the 1920s. Our results suggested that the Kuroshio transport was influenced by the combined climate modes of ENSO and PDO during the last century.

  18. Biomonitoring Equivalents for triclosan.

    PubMed

    Krishnan, Kannan; Gagné, Michelle; Nong, Andy; Aylward, Lesa L; Hays, Sean M

    2010-10-01

    Recent efforts worldwide have resulted in a growing database of measured concentrations of chemicals in blood and urine samples taken from the general population. However, few tools exist to assist in the interpretation of the measured values in a health risk context. Biomonitoring Equivalents (BEs) are defined as the concentration or range of concentrations of a chemical or its metabolite(s) in a biological medium (blood, urine, or other medium) consistent with an existing health-based exposure guideline, and are derived by integrating available data on pharmacokinetics with existing chemical risk assessments. This study reviews available health-based exposure guidance values for triclosan based on recent evaluations from the United States Environmental Protection Agency (US EPA), the European Commission's Scientific Committee on Consumer Products (EC SCCP) and the Australian National Industrial Chemicals Notification and Assessment Scheme (NICNAS). BE values corresponding to the reference dose (RfD) or margin of safety (MOS) targets from these agencies were derived based on kinetic data (urinary excretion and plasma clearance) from human studies and measured blood concentration data in animal studies. Estimated BE values for urinary total triclosan (free plus conjugates) corresponding to the US EPA RfD and the EC-identified margin of safety target from the NOAEL are 6.4 and 2.6 mg/L, respectively (corresponding to 8.3 and 3.3mg/g creatinine, respectively). Plasma BE values corresponding to the US EPA, EC, and Australian NICNAS values are 0.3, 0.9, and 0.4 mg/L, respectively. These values may be used as screening tools for evaluation of population biomonitoring data for triclosan in a risk assessment context. PMID:20541577

  19. Equivalence Principle and Gravitational Redshift

    SciTech Connect

    Hohensee, Michael A.; Chu, Steven; Mueller, Holger; Peters, Achim

    2011-04-15

    We investigate leading order deviations from general relativity that violate the Einstein equivalence principle in the gravitational standard model extension. We show that redshift experiments based on matter waves and clock comparisons are equivalent to one another. Consideration of torsion balance tests, along with matter-wave, microwave, optical, and Moessbauer clock tests, yields comprehensive limits on spin-independent Einstein equivalence principle-violating standard model extension terms at the 10{sup -6} level.

  20. Estimating equivalence with quantile regression.

    PubMed

    Cade, Brian S

    2011-01-01

    Equivalence testing and corresponding confidence interval estimates are used to provide more enlightened statistical statements about parameter estimates by relating them to intervals of effect sizes deemed to be of scientific or practical importance rather than just to an effect size of zero. Equivalence tests and confidence interval estimates are based on a null hypothesis that a parameter estimate is either outside (inequivalence hypothesis) or inside (equivalence hypothesis) an equivalence region, depending on the question of interest and assignment of risk. The former approach, often referred to as bioequivalence testing, is often used in regulatory settings because it reverses the burden of proof compared to a standard test of significance, following a precautionary principle for environmental protection. Unfortunately, many applications of equivalence testing focus on establishing average equivalence by estimating differences in means of distributions that do not have homogeneous variances. I discuss how to compare equivalence across quantiles of distributions using confidence intervals on quantile regression estimates that detect differences in heterogeneous distributions missed by focusing on means. I used one-tailed confidence intervals based on inequivalence hypotheses in a two-group treatment-control design for estimating bioequivalence of arsenic concentrations in soils at an old ammunition testing site and bioequivalence of vegetation biomass at a reclaimed mining site. Two-tailed confidence intervals based both on inequivalence and equivalence hypotheses were used to examine quantile equivalence for negligible trends over time for a continuous exponential model of amphibian abundance. PMID:21516905

  1. Psychotropic dose equivalence in Japan.

    PubMed

    Inada, Toshiya; Inagaki, Ataru

    2015-08-01

    Psychotropic dose equivalence is an important concept when estimating the approximate psychotropic doses patients receive, and deciding on the approximate titration dose when switching from one psychotropic agent to another. It is also useful from a research viewpoint when defining and extracting specific subgroups of subjects. Unification of various agents into a single standard agent facilitates easier analytical comparisons. On the basis of differences in psychopharmacological prescription features, those of available psychotropic agents and their approved doses, and racial differences between Japan and other countries, psychotropic dose equivalency tables designed specifically for Japanese patients have been widely used in Japan since 1998. Here we introduce dose equivalency tables for: (i) antipsychotics; (ii) antiparkinsonian agents; (iii) antidepressants; and (iv) anxiolytics, sedatives and hypnotics available in Japan. Equivalent doses for the therapeutic effects of individual psychotropic compounds were determined principally on the basis of randomized controlled trials conducted in Japan and consensus among dose equivalency tables reported previously by psychopharmacological experts. As these tables are intended to merely suggest approximate standard values, physicians should use them with discretion. Updated information of psychotropic dose equivalence in Japan is available at http://www.jsprs.org/en/equivalence.tables/. [Correction added on 8 July 2015, after first online publication: A link to the updated information has been added.]. PMID:25601291

  2. Equivalence-Equivalence: Matching Stimuli with Same Discriminative Functions

    ERIC Educational Resources Information Center

    Carpentier, Franck; Smeets, Paul M.; Barnes-Holmes, Dermot

    2004-01-01

    Previous studies have shown that after being trained on A-B and A-C match-to-sample tasks, adults match not only same-class B and C stimuli (equivalence) but also BC compounds with same-class elements and with different-class elements (BC-BC). The assumption was that the BC-BC performances are based on matching equivalence and nonequivalence…

  3. Equivalency Theory and Distance Education.

    ERIC Educational Resources Information Center

    Simonson, Michael

    1999-01-01

    Discusses distance education and the need for an accepted theory. Highlights include theories of independent study; theory of industrialization of teaching; theory of interaction and communication; and equivalency theory that is based on local control, personalized instruction, and telecommunications. (LRW)

  4. Optical metrics and projective equivalence

    SciTech Connect

    Casey, Stephen; Dunajski, Maciej; Gibbons, Gary; Warnick, Claude

    2011-04-15

    Trajectories of light rays in a static spacetime are described by unparametrized geodesics of the Riemannian optical metric associated with the Lorentzian spacetime metric. We investigate the uniqueness of this structure and demonstrate that two different observers, moving relative to one another, who both see the Universe as static may determine the geometry of the light rays differently. More specifically, we classify Lorentzian metrics admitting more than one hyper-surface orthogonal timelike Killing vector and analyze the projective equivalence of the resulting optical metrics. These metrics are shown to be projectively equivalent up to diffeomorphism if the static Killing vectors generate a group SL(2,R), but not projectively equivalent in general. We also consider the cosmological C metrics in Einstein-Maxwell theory and demonstrate that optical metrics corresponding to different values of the cosmological constant are projectively equivalent.

  5. Equivalent damage: A critical assessment

    NASA Technical Reports Server (NTRS)

    Laflen, J. R.; Cook, T. S.

    1982-01-01

    Concepts in equivalent damage were evaluated to determine their applicability to the life prediction of hot path components of aircraft gas turbine engines. Equivalent damage was defined as being those effects which influence the crack initiation life-time beyond the damage that is measured in uniaxial, fully-reversed sinusoidal and isothermal experiments at low homologous temperatures. Three areas of equivalent damage were examined: mean stress, cumulative damage, and multiaxiality. For each area, a literature survey was conducted to aid in selecting the most appropriate theories. Where possible, data correlations were also used in the evaluation process. A set of criteria was developed for ranking the theories in each equivalent damage regime. These criteria considered aspects of engine utilization as well as the theoretical basis and correlative ability of each theory. In addition, consideration was given to the complex nature of the loading cycle at fatigue critical locations of hot path components; this loading includes non-proportional multiaxial stressing, combined temperature and strain fluctuations, and general creep-fatigue interactions. Through applications of selected equivalent damage theories to some suitable data sets it was found that there is insufficient data to allow specific recommendations of preferred theories for general applications. A series of experiments and areas of further investigations were identified.

  6. Sievert, gray and dose equivalent.

    PubMed

    Pfalzner, P M

    1983-12-01

    The concepts of physical quantity and physical units of measurement are presented. The relations between quantities, the names and symbols for SI (International System) base units, derived units and special names of SI units are illustrated. From the definition of the radiation quantity dose equivalent, the SI unit for this quantity is shown to be dimensionally identical with the joule per kilogram. The sievert (Sv) is the special (restricted) name for the SI unit of the quantity dose equivalent, with 1 Sv = 1 J/kg. PMID:6668293

  7. Neutron Spectra and Dose Equivalent Inside Nuclear Power Reactor Containment

    SciTech Connect

    Aldrich, J. M.

    1981-08-01

    This study was conducted to determine absorbed dose, dose-equivalent rates, and neutron spectra inside containment at nuclear power plants. We gratefully acknowledge funding support by the Nuclear Regulatory Commission. The purpose of this study is: 1) measure dose-equivalent rates with various commercial types of rem meters, such as the Snoopy and Rascal, and neutron absorbed dose rates with a tissue-equivalent proportional counter 2) determine neutron spectra using the multi sphere or Bonner sphere technique and a helium-3 spectrometer 3) compare several types of personnel neutron dosimeter responses such as NTA film, polycarbonates, TLD albedo, and a recently introduced proton recoil track etch dosimeter, and CR-39. These measurements were made inside containments of pressurized water reactors (PWRs) and outside containment penetrations of boiling water reactors (BWRs) operating at full power. The neutron spectral information, absorbed dose. and dose-equivalent measurements are needed for proper interpretation of instrument and personnel dosimeter responses.

  8. Expanding the Interaction Equivalency Theorem

    ERIC Educational Resources Information Center

    Rodriguez, Brenda Cecilia Padilla; Armellini, Alejandro

    2015-01-01

    Although interaction is recognised as a key element for learning, its incorporation in online courses can be challenging. The interaction equivalency theorem provides guidelines: Meaningful learning can be supported as long as one of three types of interactions (learner-content, learner-teacher and learner-learner) is present at a high level. This…

  9. Acquired Equivalence Changes Stimulus Representations

    ERIC Educational Resources Information Center

    Meeter, M.; Shohamy, D.; Myers, C. E.

    2009-01-01

    Acquired equivalence is a paradigm in which generalization is increased between two superficially dissimilar stimuli (or antecedents) that have previously been associated with similar outcomes (or consequents). Several possible mechanisms have been proposed, including changes in stimulus representations, either in the form of added associations or…

  10. USEPA PATHOGEN EQUIVALENCY COMMITTEE RETREAT

    EPA Science Inventory

    The Pathogen Equivalency Committee held its retreat from September 20-21, 2005 at Hueston Woods State Park in College Corner, Ohio. This presentation will update the PEC’s membership on emerging pathogens, analytical methods, disinfection techniques, risk analysis, preparat...

  11. Equivalence to the Minimum Qualifications

    ERIC Educational Resources Information Center

    Academic Senate for California Community Colleges, 2006

    2006-01-01

    In 1988 the Community College Reform Act (AB 1725) began a phase out of credentials in favor of a process for establishing minimum qualifications and the determination of equivalencies that are at least equal to the state-adopted minimum qualifications for a particular discipline. According to Education Code sections 87359 and 87360, someone…

  12. Multiple Functions in Equivalence Classes

    ERIC Educational Resources Information Center

    McVeigh, Brian; Keenan, Mickey

    2009-01-01

    Four experiments examined the effects of training a "drawing" response to each of three stimuli in a 5-member equivalence class. In Experiment 1 the stimuli were an arbitrary word, a shape, or a mathematical symbol. Subjects then were trained to draw a separate component of a stickman at each of the 3 stimuli. Subsequent tests for function…

  13. Children's Equivalence Judgments: Crossmapping Effects

    ERIC Educational Resources Information Center

    Mix, Kelly S.

    2008-01-01

    Preschoolers made numerical comparisons between sets with varying degrees of shared surface similarity. When surface similarity was pitted against numerical equivalence (i.e., crossmapping), children made fewer number matches than when surface similarity was neutral (i.e, all sets contained the same objects). Only children who understood the…

  14. Equivalence to the Minimum Qualifications.

    ERIC Educational Resources Information Center

    California Community Colleges, Sacramento. Academic Senate.

    Assembly Bill (AB) 1725 provides for the hiring of faculty who do not meet the precise letter of the minimum qualifications, provided that the governing board of an institution determines that an applicant possesses qualifications that are at least equivalent. In order to make these determinations, each district must have and use an equivalency…

  15. Equivalence theorem and infrared divergences

    SciTech Connect

    Torma, T.

    1996-08-01

    We look at the equivalence theorem as a statement about the absence of polynomial infrared divergences when {ital m}{sub {ital W}}{r_arrow}0. We prove their absence in a truncated toy model and conjecture that, if they exist at all, they are due to couplings between light particles. {copyright} {ital 1996 The American Physical Society.}

  16. Experiencing Equivalence but Organizing Order

    ERIC Educational Resources Information Center

    Asghari, Amir H.

    2009-01-01

    The notion of equivalence relation is arguably one of the most fundamental ideas of mathematics. Accordingly, it plays an important role in teaching mathematics at all levels, whether explicitly or implicitly. Our success in introducing this notion for its own sake or as a means to teach other mathematical concepts, however, depends largely on our…

  17. Comparison of MCNPX and GEANT4 to Predict the Contribution of Non-elastic Nuclear Interactions to Absorbed Dose in Water, PMMA and A150

    NASA Astrophysics Data System (ADS)

    Shtejer, K.; Arruda-Neto, J. D. T.; Schulte, R.; Wroe, A.; Rodrigues, T. E.; de Menezes, M. O.; Moralles, M.; Guzmán, F.; Manso, M. V.

    2008-08-01

    Proton induced non-elastic nuclear reactions play an important role in the dose distribution of clinically used proton beams as they deposit dose of high biological effectiveness both within the primary beam path as well as outside the beam to untargeted tissues. Non-elastic nuclear reactions can be evaluated using transport codes based on the Monte Carlo method. In this work, we have utilized the Los Alamos code MCNPX and the CERN GEANT4 toolkit, which are currently the most widely used Monte Carlo programs for proton radiation transport simulations in medical physics, to study the contribution of non-elastic nuclear interactions to the absorbed dose of proton beams in the therapeutic energy range. The impact of different available theoretical models to address the nuclear reaction process was investigated. The contribution of secondary particles from non-elastic nuclear reactions was calculated in three materials relevant in radiotherapy applications: water, PMMA and A150. The results evidence that there are differences in the calculated contribution of the secondary particles heavier than protons to the absorbed dose, with different approaches to model the nuclear reactions. The MCNPX calculation give rise to a larger contribution of d, t, α3He to the total dose compared to the GEANT4 physical models chosen in this work.

  18. Comparison of MCNPX and GEANT4 to Predict the Contribution of Non-elastic Nuclear Interactions to Absorbed Dose in Water, PMMA and A150

    SciTech Connect

    Shtejer, K.; Arruda-Neto, J. D. T.; Rodrigues, T. E.; Schulte, R.; Wroe, A.; Menezes, M. O. de; Moralles, M.

    2008-08-11

    Proton induced non-elastic nuclear reactions play an important role in the dose distribution of clinically used proton beams as they deposit dose of high biological effectiveness both within the primary beam path as well as outside the beam to untargeted tissues. Non-elastic nuclear reactions can be evaluated using transport codes based on the Monte Carlo method. In this work, we have utilized the Los Alamos code MCNPX and the CERN GEANT4 toolkit, which are currently the most widely used Monte Carlo programs for proton radiation transport simulations in medical physics, to study the contribution of non-elastic nuclear interactions to the absorbed dose of proton beams in the therapeutic energy range. The impact of different available theoretical models to address the nuclear reaction process was investigated. The contribution of secondary particles from non-elastic nuclear reactions was calculated in three materials relevant in radiotherapy applications: water, PMMA and A150. The results evidence that there are differences in the calculated contribution of the secondary particles heavier than protons to the absorbed dose, with different approaches to model the nuclear reactions. The MCNPX calculation give rise to a larger contribution of d, t, {alpha}{sup 3}He to the total dose compared to the GEANT4 physical models chosen in this work.

  19. Structural analysis of artificial skin equivalents

    NASA Astrophysics Data System (ADS)

    Schmitt, Robert; Marx, Ulrich; Walles, Heike; Schober, Lena

    2011-06-01

    Artificial skin equivalents ASEs based on primary fibroblasts and keratinocytes show a high batch variance in their structural and morphological characteristics. Due to biological fluctuations and variable donor age, the growth processes of 3D tissue structure show a non constant quality. Since theses ASEs are used as testing system for chemicals, pharmaceuticals or cosmetics it is of major interest to know detailed and significant characteristics about each individual ASE. Until now, the microscopic analysis process is based on the destructive preparation of histologies allowing only the characterization on a random basis. In this study we present analytical methods to characterise each individual ASE by Optical Coherence Tomography OCT in combination with image processing tools. Therefore, we developed a fully automated OCT device, that performs automatic measurements of microtiter plates MTPs holing the ASEs in a sterile environment. We developed image processing algorithms to characterize the surface structure which may function as an indicator for defects in the epidermal stratum corneum. Further, we analysed the tomographic morphological structure of the ASEs. The results show, that variances in the growth state as well different collagen formation is detectable. In combination with dynamic threshold levels, we found, that OCT is a well suited technology for automatically characterizing artificial skin equivalents and may partly substitute the preparation of histologies.

  20. Equivalent Imperfections In Arched Structures

    NASA Astrophysics Data System (ADS)

    Dallemule, Marian

    2015-09-01

    There are currently three design methods to verify the in-plane buckling of an arched structure: substitute member method, the method of equivalent imperfection with recommendations for arched bridges, and the equivalent unique global and local initial imperfection method (EUGLI), which uses the critical elastic buckling mode as an imperfection. The latter method is included in the EN 1993-1-1 cl. 5.3.2 (11) since 2002; however, to this day it is neither utilized in the design practice nor is it incorporated in ordinary structural analysis software. The main purpose of this article is to show the application of the proposed methods in a step-by-step manner to the numerical example considered and to compare these design methods for various arched structures. Verification of the in-plane buckling of an arch is explained in detail.

  1. Information Leakage from Logically Equivalent Frames

    ERIC Educational Resources Information Center

    Sher, Shlomi; McKenzie, Craig R. M.

    2006-01-01

    Framing effects are said to occur when equivalent frames lead to different choices. However, the equivalence in question has been incompletely conceptualized. In a new normative analysis of framing effects, we complete the conceptualization by introducing the notion of information equivalence. Information equivalence obtains when no…

  2. On Vasyliunas's equivalent conductivity formalism

    NASA Technical Reports Server (NTRS)

    Pontius, D. H., Jr.

    1992-01-01

    The Vasyliunas's (1972) equivalent conductivity formalism (ECF) for representing the coupling of the ionosphere and the magnetosphere is discussed, and a new, simpler, derivation is presented of the ECF, in which certain of the underlying assumptions and their implications are made transparent. The derivation presented indicates that the only role of the ions in the ECF is to insure quasi-neutrality. It is shown that the ECF is not as robust as usually assumed and that caution must be used to insure that reasonable results are obtained.

  3. Speed analyses of stimulus equivalence.

    PubMed Central

    Spencer, T J; Chase, P N

    1996-01-01

    The functional substitutability of stimuli in equivalence classes was examined through analyses of the speed of college students' accurate responding. After training subjects to respond to 18 conditional relations, subjects' accuracy and speed of accurate responding were compared across trial types (baseline, symmetry, transitivity, and combined transitivity and symmetry) and nodal distance (one- through five-node transitive and combined transitive and symmetric relations). Differences in accuracy across nodal distance and trial type were significant only on the first tests of equivalence, whereas differences in speed were significant even after extended testing. Response speed was inversely related to the number of nodes on which the tested relations were based. Significant differences in response speed were also found across trial types, except between transitivity and combined trials. To determine the generality of these comparisons, three groups of subjects were included: An instructed group was given an instruction that specified the interchangeability of stimuli related through training; a queried group was queried about the basis for test-trial responding: and a standard group was neither instructed nor queried. There were no significant differences among groups. These results suggest the use of response speed and response accuracy to measure the strength of matching relations. PMID:8636663

  4. Therapeutic equivalents in clinical practice.

    PubMed

    Benson, M D

    2001-01-01

    With increasing debate over the rising expenses of health care, a variety of cost-saving measures has been attempted over the years. Use of primary care physicians as "gate keepers," reduction in the length of hospital stays, and pushing women toward vaginal birth after Cesarean section have all been utilized despite on going issues with patient satisfaction and even safety. One remarkable success in stretching health-care dollars that has often been overlooked is the prescription of therapeutic equivalents, or generic drugs. Although available on a limited basis for decades, off-brand manufacture of pharmaceuticals with identical active ingredients as those of the branded drug received a large boost through Congressional legislation in 1984 with the Hatch-Waxman Act. "Fast-track" FDA approval was initiated by Congress to introduce competition into the marketplace for drugs whose patients had expired. While giving close scrutiny to the manufacturing process and requiring the same level of regulatory supervision for factors such as bioavailability and shelf life, the Hatch-Waxman Act removed the burden and expense from generic manufacturers of proving the safety and efficacy all over again of a previously FDA-approved drug. With less than a 20% market share of all prescribed drugs in 1984, the generic drug industry has captured roughly 44% of the market in recent years while accounting for only 8% of expenditures on prescription medication. The prescription of therapeutic equivalents is one method of keeping health care costs down without compromising patient satisfaction or safety. PMID:11374660

  5. Equivalent crystal theory of alloys

    NASA Technical Reports Server (NTRS)

    Bozzolo, Guillermo; Ferrante, John

    1991-01-01

    Equivalent Crystal Theory (ECT) is a new, semi-empirical approach to calculating the energetics of a solid with defects. The theory has successfully reproduced surface energies in metals and semiconductors. The theory of binary alloys to date, both with first-principles and semi-empirical models, has not been very successful in predicting the energetics of alloys. This procedure is used to predict the heats of formation, cohesive energy, and lattice parameter of binary alloys of Cu, Ni, Al, Ag, Au, Pd, and Pt as functions of composition. The procedure accurately reproduces the heats of formation versus composition curves for a variety of binary alloys. The results are then compared with other approaches such as the embedded atom and lattice parameters of alloys from pure metal properties more accurately than Vegard's law is presented.

  6. Light WIMPs and Equivalent Neutrinos

    NASA Astrophysics Data System (ADS)

    Steigman, Gary; Nollett, Kenneth M.

    Very light WIMPs (χ), thermal relics that annihilate late in the early Universe, change the energy and entropy densities at BBN and at recombination. BBN, in combination with the CMB, can remove some of the degeneracies among light WIMPs and equivalent neutrinos, constraining the existence and properties of each. Depending on the nature of the light WIMP (Majorana or Dirac fermion, real or complex scalar) the joint BBN + CMB analyses set lower bounds to mχ in the range 0.5 - 5 MeV (mχ/me ≲1 - 10), and they identify best fit values for mχ in the range 5 - 10 MeV. The joint BBN + CMB analysis finds a best fit value for the number of equivalent neutrinos, ΔNν ≈ 0.65, nearly independent of the nature of the WIMP. In the absence of a light WIMP (mχ ≲20 MeV), Neff = 3.05(1 + ΔNν/3). In this case, there is excellent agreement between BBN and the CMB, but the joint fit reveals ΔNν = 0.40 ± 0.17, disfavoring standard big bang nucleosynthesis (SBBN) (ΔNν = 0) at ∼ 2.4 σ, as well as a sterile neutrino (ΔNν = 1) at ∼ 3.5 σ. The best BBN + CMB joint fit disfavors the absence of dark radiation (ΔNν = 0 at ∼ 95% confidence), while allowing for the presence of a sterile neutrino (ΔNν = 1 at ≲1 σ). For all cases considered here, the lithium problem persists. These results, presented at the TAUP 2013 Conference, are based on Nollett & Steigman [14].

  7. Verification of an effective dose equivalent model for neutrons

    SciTech Connect

    Tanner, J.E.; Piper, R.K.; Leonowich, J.A.; Faust, L.G.

    1991-10-01

    Since the effective dose equivalent, based on the weighted sum of organ dose equivalents, is not a directly measurable quantity, it must be estimated with the assistance of computer modeling techniques and a knowledge of the radiation field. Although extreme accuracy is not necessary for radiation protection purposes, a few well-chosen measurements are required to confirm the theoretical models. Neutron measurements were performed in a RANDO phantom using thermoluminescent dosemeters, track etch dosemeters, and a 1/2-in. (1.27-cm) tissue equivalent proportional counter in order to estimate neutron doses and dose equivalents within the phantom at specific locations. The phantom was exposed to bare and D{sub 2}O-moderated {sup 252}Cf neutrons at the Pacific Northwest Laboratory's Low Scatter Facility. The Monte Carlo code MCNP with the MIRD-V mathematical phantom was used to model the human body and calculate organ doses and dose equivalents. The experimental methods are described and the results of the measurements are compared to the calculations. 8 refs., 3 figs., 3 tabs.

  8. Verification of an effective dose equivalent model for neutrons

    NASA Astrophysics Data System (ADS)

    Tanner, J. E.; Piper, R. K.; Leonowich, J. A.; Faust, L. G.

    1991-10-01

    Since the effective dose equivalent, based on the weighted sum of organ dose equivalents, is not a directly measurable quantity, it must be estimated with the assistance of computer modeling techniques and a knowledge of the radiation field. Although extreme accuracy is not necessary for radiation protection purposes, a few well chosen measurements are required to confirm the theoretical models. Neutron measurements were performed in a RANDO phantom using thermoluminescent dosemeters, track etch dosemeters, and a 1/2 in. (1.27 cm) tissue equivalent proportional counter in order to estimate neutron doses and dose equivalents within the phantom at specific locations. The phantom was exposed to bare and D2O-moderated Cf-252 neutrons at the Pacific Northwest Laboratory's Low Scatter Facility. The Monte Carlo code MCNP with the MIRD-V mathematical phantom was used to model the human body and calculate organ doses and dose equivalents. The experimental methods are described and the results of the measurements are compared to the calculations.

  9. Preliminary design of a 150 kJ repetitive plasma focus for the production of 18-F

    NASA Astrophysics Data System (ADS)

    Sumini, Marco; Mostacci, Domiziano; Rocchi, Federico; Frignani, Michele; Tartari, Agostino; Angeli, Ergisto; Galaverni, Dario; Coli, Ugo; Ascione, Bernardino; Cucchi, Giorgio

    2006-06-01

    Experiments in the past five years have demonstrated production of short-lived radioisotopes with a Plasma Focus device, using the so-termed Endogenous Mode. So far radioisotope activities of only a few microcuries have been obtained from single discharges in small scale Plasma Focus machines (capacitor bank energies of approximately 7 kJ). It is expected that higher activities could be obtained with larger bank energies, operating at high pulse repetition rates, e.g. 1 Hz. However, many scientific and technological issues must be addressed for a high-energy Plasma Focus device to run at one pulse per second. Aim of this paper is to present preliminary results pertaining to the plasma, electrical, fluid-dynamical, thermal, material and mechanical design of a 150 kJ Plasma Focus, capable of a repetition rate of 1 Hz, that will be operated at 30 kV with a 350 μF capacitor bank and a maximum total current of 1.5 MA. This device will be used to breed 18-F for the synthesis of drugs used in positron-emission medical examinations, such as FDG for PET.

  10. 46 CFR 110.20-1 - Equivalents.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Equivalents. 110.20-1 Section 110.20-1 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) ELECTRICAL ENGINEERING GENERAL PROVISIONS Equivalents... engineering evaluations and tests to demonstrate the equivalence of the substitute....

  11. 46 CFR 110.20-1 - Equivalents.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 4 2011-10-01 2011-10-01 false Equivalents. 110.20-1 Section 110.20-1 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) ELECTRICAL ENGINEERING GENERAL PROVISIONS Equivalents... engineering evaluations and tests to demonstrate the equivalence of the substitute....

  12. 46 CFR 110.20-1 - Equivalents.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 4 2014-10-01 2014-10-01 false Equivalents. 110.20-1 Section 110.20-1 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) ELECTRICAL ENGINEERING GENERAL PROVISIONS Equivalents... engineering evaluations and tests to demonstrate the equivalence of the substitute....

  13. 21 CFR 26.6 - Equivalence assessment.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 1 2014-04-01 2014-04-01 false Equivalence assessment. 26.6 Section 26.6 Food and... Specific Sector Provisions for Pharmaceutical Good Manufacturing Practices § 26.6 Equivalence assessment... or processes. (c) The equivalence assessment shall include information exchanges...

  14. 21 CFR 26.39 - Equivalence assessment.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 1 2012-04-01 2012-04-01 false Equivalence assessment. 26.39 Section 26.39 Food... Specific Sector Provisions for Medical Devices § 26.39 Equivalence assessment. (a) In the final 6 months of the transition period, the parties shall proceed to a joint assessment of the equivalence of...

  15. 21 CFR 26.39 - Equivalence assessment.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 1 2011-04-01 2011-04-01 false Equivalence assessment. 26.39 Section 26.39 Food... Specific Sector Provisions for Medical Devices § 26.39 Equivalence assessment. (a) In the final 6 months of the transition period, the parties shall proceed to a joint assessment of the equivalence of...

  16. 21 CFR 26.6 - Equivalence assessment.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 1 2011-04-01 2011-04-01 false Equivalence assessment. 26.6 Section 26.6 Food and... Specific Sector Provisions for Pharmaceutical Good Manufacturing Practices § 26.6 Equivalence assessment... or processes. (c) The equivalence assessment shall include information exchanges...

  17. Equivalency Testing in Development of Health Practitioners

    ERIC Educational Resources Information Center

    Wilson, Margaret A.

    1974-01-01

    A faculty must think effectivelyto build a congruent meaningful equivalency testing effort as an intimate part of its curriculum. No faculty should feel embarrassed if its conclusion, after careful assessment, is that it cannot or should not offer equivalency testing. Each faculty should study equivalency testing and its feasibility. (Author/AJ)

  18. Classroom Activities for Introducing Equivalence Relations

    ERIC Educational Resources Information Center

    Brandt, Jim

    2013-01-01

    Equivalence relations and partitions are two interconnected ideas that play important roles in advanced mathematics. While students encounter the informal notion of equivalence in many courses, the formal definition of an equivalence relation is typically introduced in a junior level transition-to-proof course. This paper reports the results of a…

  19. 46 CFR 110.20-1 - Equivalents.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 4 2013-10-01 2013-10-01 false Equivalents. 110.20-1 Section 110.20-1 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) ELECTRICAL ENGINEERING GENERAL PROVISIONS Equivalents... engineering evaluations and tests to demonstrate the equivalence of the substitute....

  20. 46 CFR 110.20-1 - Equivalents.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 4 2012-10-01 2012-10-01 false Equivalents. 110.20-1 Section 110.20-1 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) ELECTRICAL ENGINEERING GENERAL PROVISIONS Equivalents... engineering evaluations and tests to demonstrate the equivalence of the substitute....

  1. AGR-2 Data Qualification Report for ATR Cycles 149B, 150A, 150B, 151A, and 151B

    SciTech Connect

    Michael L. Abbott; Binh T. Pham

    2012-06-01

    This report provides the data qualification status of AGR-2 fuel irradiation experimental data from Advanced Test Reactor (ATR) cycles 149B, 150A, 150B, 151A, and 151B), as recorded in the Nuclear Data Management and Analysis System (NDMAS). The AGR-2 data streams addressed include thermocouple temperatures, sweep gas data (flow rate, pressure, and moisture content), and fission product monitoring system (FPMS) data for each of the six capsules in the experiment. A total of 3,307,500 5-minute thermocouple and sweep gas data records were received and processed by NDMAS for this period. There are no AGR-2 data for cycle 150A because the experiment was removed from the reactor. Of these data, 82.2% were determined to be Qualified based on NDMAS accuracy testing and data validity assessment. There were 450,557 Failed temperature records due to thermocouple failures, and 138,528 Failed gas flow records due to gas flow cross-talk and leakage problems that occurred in the capsules after cycle 150A. For FPMS data, NDMAS received and processed preliminary release rate and release-to-birth rate ratio (R/B) data for the first three reactor cycles (cycles 149B, 150B, and 151B). This data consists of 45,983 release rate records and 45,235 R/B records for the 12 radionuclides reported. The qualification status of these FPMS data has been set to In Process until receipt of QA-approved data generator reports. All of the above data have been processed and tested using a SAS®-based enterprise application software system, stored in a secure Structured Query Language database, and made available on the NDMAS Web portal (http://ndmas.inl.gov) for both internal and external VHTR project participants.

  2. It Pays to Be Organized: Organizing Arithmetic Practice around Equivalent Values Facilitates Understanding of Math Equivalence

    ERIC Educational Resources Information Center

    McNeil, Nicole M.; Chesney, Dana L.; Matthews, Percival G.; Fyfe, Emily R.; Petersen, Lori A.; Dunwiddie, April E.; Wheeler, Mary C.

    2012-01-01

    This experiment tested the hypothesis that organizing arithmetic fact practice by equivalent values facilitates children's understanding of math equivalence. Children (M age = 8 years 6 months, N = 104) were randomly assigned to 1 of 3 practice conditions: (a) equivalent values, in which problems were grouped by equivalent sums (e.g., 3 + 4 = 7, 2…

  3. 21 CFR 26.6 - Equivalence assessment.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... OF PHARMACEUTICAL GOOD MANUFACTURING PRACTICE REPORTS, MEDICAL DEVICE QUALITY SYSTEM AUDIT REPORTS... Specific Sector Provisions for Pharmaceutical Good Manufacturing Practices § 26.6 Equivalence...

  4. 21 CFR 26.9 - Equivalence determination.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... RECOGNITION OF PHARMACEUTICAL GOOD MANUFACTURING PRACTICE REPORTS, MEDICAL DEVICE QUALITY SYSTEM AUDIT REPORTS... Specific Sector Provisions for Pharmaceutical Good Manufacturing Practices § 26.9 Equivalence...

  5. Pooling Morphometric Estimates: A Statistical Equivalence Approach.

    PubMed

    Pardoe, Heath R; Cutter, Gary R; Alter, Rachel; Hiess, Rebecca Kucharsky; Semmelroch, Mira; Parker, Donna; Farquharson, Shawna; Jackson, Graeme D; Kuzniecky, Ruben

    2016-01-01

    Changes in hardware or image-processing settings are a common issue for large multicenter studies. To pool MRI data acquired under these changed conditions, it is necessary to demonstrate that the changes do not affect MRI-based measurements. In these circumstances, classical inference testing is inappropriate because it is designed to detect differences, not prove similarity. We used a method known as statistical equivalence testing to address this limitation. Equivalence testing was carried out on 3 datasets: (1) cortical thickness and automated hippocampal volume estimates obtained from healthy individuals imaged using different multichannel head coils; (2) manual hippocampal volumetry obtained using two readers; and (3) corpus callosum area estimates obtained using an automated method with manual cleanup carried out by two readers. Equivalence testing was carried out using the "two one-sided tests" (TOST) approach. Power analyses of the TOST were used to estimate sample sizes required for well-powered equivalence testing analyses. Mean and standard deviation estimates from the automated hippocampal volume dataset were used to carry out an example power analysis. Cortical thickness values were found to be equivalent over 61% of the cortex when different head coils were used (q < .05, false discovery rate correction). Automated hippocampal volume estimates obtained using the same two coils were statistically equivalent (TOST P = 4.28 × 10(-15) ). Manual hippocampal volume estimates obtained using two readers were not statistically equivalent (TOST P = .97). The use of different readers to carry out limited correction of automated corpus callosum segmentations yielded equivalent area estimates (TOST P = 1.28 × 10(-14) ). Power analysis of simulated and automated hippocampal volume data demonstrated that the equivalence margin affects the number of subjects required for well-powered equivalence tests. We have presented a statistical method for determining if

  6. 7 CFR 1126.54 - Equivalent price.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 9 2010-01-01 2009-01-01 true Equivalent price. 1126.54 Section 1126.54 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing Agreements... Handling Class Prices § 1126.54 Equivalent price. See § 1000.54. Producer Price Differential...

  7. 7 CFR 1006.54 - Equivalent price.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 9 2010-01-01 2009-01-01 true Equivalent price. 1006.54 Section 1006.54 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing Agreements... Handling Class Prices § 1006.54 Equivalent price. See § 1000.54. Uniform Prices...

  8. 7 CFR 1033.54 - Equivalent price.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 9 2010-01-01 2009-01-01 true Equivalent price. 1033.54 Section 1033.54 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing Agreements... Handling Class Prices § 1033.54 Equivalent price. See § 1000.54. Producer Price Differential...

  9. 7 CFR 1032.54 - Equivalent price.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 9 2010-01-01 2009-01-01 true Equivalent price. 1032.54 Section 1032.54 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing Agreements... Handling Class Prices § 1032.54 Equivalent price. See § 1000.54. Producer Price Differential...

  10. 7 CFR 1000.54 - Equivalent price.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 9 2010-01-01 2009-01-01 true Equivalent price. 1000.54 Section 1000.54 Agriculture... Prices § 1000.54 Equivalent price. If for any reason a price or pricing constituent required for computing the prices described in § 1000.50 is not available, the market administrator shall use a price...

  11. 7 CFR 1131.54 - Equivalent price.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 9 2010-01-01 2009-01-01 true Equivalent price. 1131.54 Section 1131.54 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing Agreements... Handling Class Prices § 1131.54 Equivalent price. See § 1000.54. Uniform Prices...

  12. 7 CFR 1030.54 - Equivalent price.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 9 2010-01-01 2009-01-01 true Equivalent price. 1030.54 Section 1030.54 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing Agreements... Handling Class Prices § 1030.54 Equivalent price. See § 1000.54....

  13. 7 CFR 1007.54 - Equivalent price.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 9 2010-01-01 2009-01-01 true Equivalent price. 1007.54 Section 1007.54 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing Agreements... Handling Class Prices § 1007.54 Equivalent price. See § 1000.54. Uniform Prices...

  14. 7 CFR 1124.54 - Equivalent price.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 9 2010-01-01 2009-01-01 true Equivalent price. 1124.54 Section 1124.54 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing Agreements... Regulating Handling Class Prices § 1124.54 Equivalent price. See § 1000.54. Producer Price Differential...

  15. 7 CFR 1001.54 - Equivalent price.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 9 2010-01-01 2009-01-01 true Equivalent price. 1001.54 Section 1001.54 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing Agreements... Handling Class Prices § 1001.54 Equivalent price. See § 1000.54. Producer Price Differential...

  16. 7 CFR 1005.54 - Equivalent price.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 9 2010-01-01 2009-01-01 true Equivalent price. 1005.54 Section 1005.54 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing Agreements... Handling Class Prices § 1005.54 Equivalent price. See § 1000.54. Uniform Prices...

  17. 33 CFR 106.130 - Equivalents.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 1 2012-07-01 2012-07-01 false Equivalents. 106.130 Section 106.130 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY MARITIME SECURITY MARINE SECURITY: OUTER CONTINENTAL SHELF (OCS) FACILITIES General § 106.130 Equivalents. For any...

  18. 33 CFR 106.130 - Equivalents.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 1 2014-07-01 2014-07-01 false Equivalents. 106.130 Section 106.130 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY MARITIME SECURITY MARINE SECURITY: OUTER CONTINENTAL SHELF (OCS) FACILITIES General § 106.130 Equivalents. For any...

  19. 46 CFR 114.540 - Equivalents.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... equivalence of the substitute. (b) The Commandant may accept compliance by a high speed craft with the provisions of the International Maritime Organization (IMO) “Code of Safety for High Speed Craft” as an... approve a novel lifesaving appliance or arrangement as an equivalent if it has performance...

  20. 46 CFR 175.540 - Equivalents.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... Commandant may accept compliance by a high speed craft with the provisions of the International Maritime Organization (IMO) “Code of Safety for High Speed Craft” as an equivalent to compliance with applicable... lifesaving appliance or arrangement as an equivalent if it has performance characteristics at...

  1. 33 CFR 106.130 - Equivalents.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 1 2013-07-01 2013-07-01 false Equivalents. 106.130 Section 106.130 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY MARITIME SECURITY MARINE SECURITY: OUTER CONTINENTAL SHELF (OCS) FACILITIES General § 106.130 Equivalents. For any...

  2. 7 CFR 1030.54 - Equivalent price.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 9 2012-01-01 2012-01-01 false Equivalent price. 1030.54 Section 1030.54 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing Agreements... Handling Class Prices § 1030.54 Equivalent price. See § 1000.54....

  3. 7 CFR 1033.54 - Equivalent price.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 9 2013-01-01 2013-01-01 false Equivalent price. 1033.54 Section 1033.54 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (MARKETING AGREEMENTS... Handling Class Prices § 1033.54 Equivalent price. See § 1000.54. Producer Price Differential...

  4. 7 CFR 1124.54 - Equivalent price.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 9 2011-01-01 2011-01-01 false Equivalent price. 1124.54 Section 1124.54 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing Agreements... Regulating Handling Class Prices § 1124.54 Equivalent price. See § 1000.54. Producer Price Differential...

  5. 7 CFR 1131.54 - Equivalent price.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 9 2014-01-01 2013-01-01 true Equivalent price. 1131.54 Section 1131.54 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (MARKETING AGREEMENTS... Handling Class Prices § 1131.54 Equivalent price. See § 1000.54. Uniform Prices...

  6. 7 CFR 1033.54 - Equivalent price.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 9 2014-01-01 2013-01-01 true Equivalent price. 1033.54 Section 1033.54 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (MARKETING AGREEMENTS... Handling Class Prices § 1033.54 Equivalent price. See § 1000.54. Producer Price Differential...

  7. 7 CFR 1006.54 - Equivalent price.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 9 2013-01-01 2013-01-01 false Equivalent price. 1006.54 Section 1006.54 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (MARKETING AGREEMENTS... Handling Class Prices § 1006.54 Equivalent price. See § 1000.54. Uniform Prices...

  8. 7 CFR 1007.54 - Equivalent price.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 9 2013-01-01 2013-01-01 false Equivalent price. 1007.54 Section 1007.54 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (MARKETING AGREEMENTS... Handling Class Prices § 1007.54 Equivalent price. See § 1000.54. Uniform Prices...

  9. 7 CFR 1033.54 - Equivalent price.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 9 2011-01-01 2011-01-01 false Equivalent price. 1033.54 Section 1033.54 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing Agreements... Handling Class Prices § 1033.54 Equivalent price. See § 1000.54. Producer Price Differential...

  10. 7 CFR 1001.54 - Equivalent price.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 9 2013-01-01 2013-01-01 false Equivalent price. 1001.54 Section 1001.54 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (MARKETING AGREEMENTS... Handling Class Prices § 1001.54 Equivalent price. See § 1000.54. Producer Price Differential...

  11. 7 CFR 1000.54 - Equivalent price.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 9 2012-01-01 2012-01-01 false Equivalent price. 1000.54 Section 1000.54 Agriculture... Prices § 1000.54 Equivalent price. If for any reason a price or pricing constituent required for computing the prices described in § 1000.50 is not available, the market administrator shall use a price...

  12. 7 CFR 1007.54 - Equivalent price.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 9 2014-01-01 2013-01-01 true Equivalent price. 1007.54 Section 1007.54 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (MARKETING AGREEMENTS... Handling Class Prices § 1007.54 Equivalent price. See § 1000.54. Uniform Prices...

  13. 7 CFR 1131.54 - Equivalent price.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 9 2012-01-01 2012-01-01 false Equivalent price. 1131.54 Section 1131.54 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing Agreements... Handling Class Prices § 1131.54 Equivalent price. See § 1000.54. Uniform Prices...

  14. 7 CFR 1007.54 - Equivalent price.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 9 2012-01-01 2012-01-01 false Equivalent price. 1007.54 Section 1007.54 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing Agreements... Handling Class Prices § 1007.54 Equivalent price. See § 1000.54. Uniform Prices...

  15. 7 CFR 1001.54 - Equivalent price.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 9 2011-01-01 2011-01-01 false Equivalent price. 1001.54 Section 1001.54 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing Agreements... Handling Class Prices § 1001.54 Equivalent price. See § 1000.54. Producer Price Differential...

  16. 7 CFR 1030.54 - Equivalent price.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 9 2013-01-01 2013-01-01 false Equivalent price. 1030.54 Section 1030.54 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (MARKETING AGREEMENTS... Handling Class Prices § 1030.54 Equivalent price. See § 1000.54....

  17. 7 CFR 1126.54 - Equivalent price.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 9 2014-01-01 2013-01-01 true Equivalent price. 1126.54 Section 1126.54 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (MARKETING AGREEMENTS... Handling Class Prices § 1126.54 Equivalent price. See § 1000.54. Producer Price Differential...

  18. 7 CFR 1126.54 - Equivalent price.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 9 2011-01-01 2011-01-01 false Equivalent price. 1126.54 Section 1126.54 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing Agreements... Handling Class Prices § 1126.54 Equivalent price. See § 1000.54. Producer Price Differential...

  19. 7 CFR 1006.54 - Equivalent price.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 9 2012-01-01 2012-01-01 false Equivalent price. 1006.54 Section 1006.54 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing Agreements... Handling Class Prices § 1006.54 Equivalent price. See § 1000.54. Uniform Prices...

  20. 7 CFR 1007.54 - Equivalent price.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 9 2011-01-01 2011-01-01 false Equivalent price. 1007.54 Section 1007.54 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing Agreements... Handling Class Prices § 1007.54 Equivalent price. See § 1000.54. Uniform Prices...

  1. 7 CFR 1006.54 - Equivalent price.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 9 2014-01-01 2013-01-01 true Equivalent price. 1006.54 Section 1006.54 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (MARKETING AGREEMENTS... Handling Class Prices § 1006.54 Equivalent price. See § 1000.54. Uniform Prices...

  2. 7 CFR 1032.54 - Equivalent price.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 9 2012-01-01 2012-01-01 false Equivalent price. 1032.54 Section 1032.54 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing Agreements... Handling Class Prices § 1032.54 Equivalent price. See § 1000.54. Producer Price Differential...

  3. 7 CFR 1000.54 - Equivalent price.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 9 2011-01-01 2011-01-01 false Equivalent price. 1000.54 Section 1000.54 Agriculture... Prices § 1000.54 Equivalent price. If for any reason a price or pricing constituent required for computing the prices described in § 1000.50 is not available, the market administrator shall use a price...

  4. 7 CFR 1126.54 - Equivalent price.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 9 2013-01-01 2013-01-01 false Equivalent price. 1126.54 Section 1126.54 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (MARKETING AGREEMENTS... Handling Class Prices § 1126.54 Equivalent price. See § 1000.54. Producer Price Differential...

  5. 7 CFR 1126.54 - Equivalent price.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 9 2012-01-01 2012-01-01 false Equivalent price. 1126.54 Section 1126.54 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing Agreements... Handling Class Prices § 1126.54 Equivalent price. See § 1000.54. Producer Price Differential...

  6. 7 CFR 1001.54 - Equivalent price.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 9 2014-01-01 2013-01-01 true Equivalent price. 1001.54 Section 1001.54 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (MARKETING AGREEMENTS... Handling Class Prices § 1001.54 Equivalent price. See § 1000.54. Producer Price Differential...

  7. 7 CFR 1000.54 - Equivalent price.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 9 2014-01-01 2013-01-01 true Equivalent price. 1000.54 Section 1000.54 Agriculture... Prices § 1000.54 Equivalent price. If for any reason a price or pricing constituent required for computing the prices described in § 1000.50 is not available, the market administrator shall use a price...

  8. 7 CFR 1032.54 - Equivalent price.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 9 2014-01-01 2013-01-01 true Equivalent price. 1032.54 Section 1032.54 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (MARKETING AGREEMENTS... Handling Class Prices § 1032.54 Equivalent price. See § 1000.54. Producer Price Differential...

  9. 7 CFR 1001.54 - Equivalent price.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 9 2012-01-01 2012-01-01 false Equivalent price. 1001.54 Section 1001.54 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing Agreements... Handling Class Prices § 1001.54 Equivalent price. See § 1000.54. Producer Price Differential...

  10. 7 CFR 1006.54 - Equivalent price.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 9 2011-01-01 2011-01-01 false Equivalent price. 1006.54 Section 1006.54 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing Agreements... Handling Class Prices § 1006.54 Equivalent price. See § 1000.54. Uniform Prices...

  11. 7 CFR 1124.54 - Equivalent price.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 9 2014-01-01 2013-01-01 true Equivalent price. 1124.54 Section 1124.54 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (MARKETING AGREEMENTS... Regulating Handling Class Prices § 1124.54 Equivalent price. See § 1000.54. Producer Price Differential...

  12. 7 CFR 1030.54 - Equivalent price.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 9 2014-01-01 2013-01-01 true Equivalent price. 1030.54 Section 1030.54 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (MARKETING AGREEMENTS... Handling Class Prices § 1030.54 Equivalent price. See § 1000.54....

  13. 7 CFR 1124.54 - Equivalent price.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 9 2013-01-01 2013-01-01 false Equivalent price. 1124.54 Section 1124.54 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (MARKETING AGREEMENTS... Regulating Handling Class Prices § 1124.54 Equivalent price. See § 1000.54. Producer Price Differential...

  14. 7 CFR 1033.54 - Equivalent price.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 9 2012-01-01 2012-01-01 false Equivalent price. 1033.54 Section 1033.54 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing Agreements... Handling Class Prices § 1033.54 Equivalent price. See § 1000.54. Producer Price Differential...

  15. 7 CFR 1131.54 - Equivalent price.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 9 2013-01-01 2013-01-01 false Equivalent price. 1131.54 Section 1131.54 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (MARKETING AGREEMENTS... Handling Class Prices § 1131.54 Equivalent price. See § 1000.54. Uniform Prices...

  16. 7 CFR 1124.54 - Equivalent price.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 9 2012-01-01 2012-01-01 false Equivalent price. 1124.54 Section 1124.54 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing Agreements... Regulating Handling Class Prices § 1124.54 Equivalent price. See § 1000.54. Producer Price Differential...

  17. 7 CFR 1000.54 - Equivalent price.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 9 2013-01-01 2013-01-01 false Equivalent price. 1000.54 Section 1000.54 Agriculture... Prices § 1000.54 Equivalent price. If for any reason a price or pricing constituent required for computing the prices described in § 1000.50 is not available, the market administrator shall use a price...

  18. 7 CFR 1032.54 - Equivalent price.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 9 2011-01-01 2011-01-01 false Equivalent price. 1032.54 Section 1032.54 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing Agreements... Handling Class Prices § 1032.54 Equivalent price. See § 1000.54. Producer Price Differential...

  19. 7 CFR 1030.54 - Equivalent price.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 9 2011-01-01 2011-01-01 false Equivalent price. 1030.54 Section 1030.54 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing Agreements... Handling Class Prices § 1030.54 Equivalent price. See § 1000.54....

  20. 7 CFR 1032.54 - Equivalent price.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 9 2013-01-01 2013-01-01 false Equivalent price. 1032.54 Section 1032.54 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (MARKETING AGREEMENTS... Handling Class Prices § 1032.54 Equivalent price. See § 1000.54. Producer Price Differential...

  1. 7 CFR 1131.54 - Equivalent price.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 9 2011-01-01 2011-01-01 false Equivalent price. 1131.54 Section 1131.54 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing Agreements... Handling Class Prices § 1131.54 Equivalent price. See § 1000.54. Uniform Prices...

  2. 33 CFR 159.19 - Testing equivalency.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Testing equivalency. 159.19 Section 159.19 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) POLLUTION MARINE SANITATION DEVICES Certification Procedures § 159.19 Testing equivalency. (a) If a...

  3. Equivalent Mass of a Coil Spring.

    ERIC Educational Resources Information Center

    Ruby, Lawrence

    2000-01-01

    Finds that first-year college students can understand in detail the origin of the equivalent mass. Provides both a simple calculation derivation of this result as well as a noncalculus derivation. Argues that for every soft spring, the equivalent mass should be somewhere between m0/3 and m0/2. (CCM)

  4. 29 CFR 825.215 - Equivalent position.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 29 Labor 3 2011-07-01 2011-07-01 false Equivalent position. 825.215 Section 825.215 Labor Regulations Relating to Labor (Continued) WAGE AND HOUR DIVISION, DEPARTMENT OF LABOR OTHER LAWS THE FAMILY AND MEDICAL LEAVE ACT OF 1993 Employee Leave Entitlements Under the Family and Medical Leave Act § 825.215 Equivalent position. (a)...

  5. 46 CFR 169.109 - Equivalents.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 7 2014-10-01 2014-10-01 false Equivalents. 169.109 Section 169.109 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) NAUTICAL SCHOOLS SAILING SCHOOL VESSELS General Provisions § 169.109 Equivalents. Substitutes for a fitting, appliance, apparatus, or equipment, may...

  6. 46 CFR 169.109 - Equivalents.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 7 2012-10-01 2012-10-01 false Equivalents. 169.109 Section 169.109 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) NAUTICAL SCHOOLS SAILING SCHOOL VESSELS General Provisions § 169.109 Equivalents. Substitutes for a fitting, appliance, apparatus, or equipment, may...

  7. 46 CFR 169.109 - Equivalents.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 7 2011-10-01 2011-10-01 false Equivalents. 169.109 Section 169.109 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) NAUTICAL SCHOOLS SAILING SCHOOL VESSELS General Provisions § 169.109 Equivalents. Substitutes for a fitting, appliance, apparatus, or equipment, may...

  8. 46 CFR 169.109 - Equivalents.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Equivalents. 169.109 Section 169.109 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) NAUTICAL SCHOOLS SAILING SCHOOL VESSELS General Provisions § 169.109 Equivalents. Substitutes for a fitting, appliance, apparatus, or equipment, may...

  9. 46 CFR 169.109 - Equivalents.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 7 2013-10-01 2013-10-01 false Equivalents. 169.109 Section 169.109 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) NAUTICAL SCHOOLS SAILING SCHOOL VESSELS General Provisions § 169.109 Equivalents. Substitutes for a fitting, appliance, apparatus, or equipment, may...

  10. 46 CFR 170.010 - Equivalents.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Equivalents. 170.010 Section 170.010 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) SUBDIVISION AND STABILITY STABILITY REQUIREMENTS FOR ALL INSPECTED VESSELS General Provisions § 170.010 Equivalents. Substitutions for fittings,...

  11. Equivalence in Ventilation and Indoor Air Quality

    SciTech Connect

    Sherman, Max; Walker, Iain; Logue, Jennifer

    2011-08-01

    We ventilate buildings to provide acceptable indoor air quality (IAQ). Ventilation standards (such as American Society of Heating, Refrigerating, and Air-Conditioning Enginners [ASHRAE] Standard 62) specify minimum ventilation rates without taking into account the impact of those rates on IAQ. Innovative ventilation management is often a desirable element of reducing energy consumption or improving IAQ or comfort. Variable ventilation is one innovative strategy. To use variable ventilation in a way that meets standards, it is necessary to have a method for determining equivalence in terms of either ventilation or indoor air quality. This study develops methods to calculate either equivalent ventilation or equivalent IAQ. We demonstrate that equivalent ventilation can be used as the basis for dynamic ventilation control, reducing peak load and infiltration of outdoor contaminants. We also show that equivalent IAQ could allow some contaminants to exceed current standards if other contaminants are more stringently controlled.

  12. The Assessment of Effective Dose Equivalent Using Personnel Dosimeters

    NASA Astrophysics Data System (ADS)

    Xu, Xie

    From January 1994, U.S. nuclear plants must develop a technically rigorous approach for determining the effective dose equivalent for their work forces. This dissertation explains concepts associated with effective dose equivalent and describes how to assess effective dose equivalent by using conventional personnel dosimetry measurements. A Monte Carlo computer code, MCNP, was used to calculate photon transport through a model of the human body. Published mathematical phantoms of the human adult male and female were used to simulate irradiation from a variety of external radiation sources in order to calculate organ and tissue doses, as well as effective dose equivalent using weighting factors from ICRP Publication 26. The radiation sources considered were broad parallel photon beams incident on the body from 91 different angles and isotropic point sources located at 234 different locations in contact with or near the body. Monoenergetic photons of 0.08, 0.3, and 1.0 MeV were considered for both sources. Personnel dosimeters were simulated on the surface of the body and exposed to with the same sources. From these data, the influence of dosimeter position on dosimeter response was investigated. Different algorithms for assessing effective dose equivalent from personnel dosimeter responses were proposed and evaluated. The results indicate that the current single-badge approach is satisfactory for most common exposure situations encountered in nuclear plants, but additional conversion factors may be used when more accurate results become desirable. For uncommon exposures involving source situated at the back of the body or source located overhead, the current approach of using multi-badges and assigning the highest dose is overly conservative and unnecessarily expensive. For these uncommon exposures, a new algorithm, based on two dosimeters, one on the front of the body and another one on the back of the body, has been shown to yield conservative assessment of

  13. Equivalence-Equivalence Responding: Training Conditions Involved in Obtaining a Stable Baseline Performance

    ERIC Educational Resources Information Center

    Garcia, Andres; Bohorquez, Cristobal; Perez, Vicente; Gutierrez, Maria Teresa; Gomez, Jesus; Luciano, Carmen; Wilson, Kelly

    2008-01-01

    Recent research has focused on the variables associated with equivalence-equivalence responding, in which participants match pairs of equivalent or nonequivalent stimuli. One such variable is the presence of response competition from nonarbitrary (physical) relational response options. In the current analysis, the experimenters examined the effect…

  14. 77 FR 55832 - Ambient Air Monitoring Reference and Equivalent Methods: Designation of a New Equivalent Method

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-09-11

    ... made under the provisions of 40 CFR part 53, as ] amended on August 31, 2011 (76 FR 54326-54341). The... AGENCY Ambient Air Monitoring Reference and Equivalent Methods: Designation of a New Equivalent Method AGENCY: Environmental Protection Agency. ACTION: Notice of the designation of a new equivalent method...

  15. 77 FR 60985 - Ambient Air Monitoring Reference and Equivalent Methods: Designation of Three New Equivalent Methods

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-10-05

    ... 53, as amended on August 31, 2011 (76 FR 54326-54341). The new equivalent methods are automated... AGENCY Ambient Air Monitoring Reference and Equivalent Methods: Designation of Three New Equivalent Methods AGENCY: Environmental Protection Agency. ACTION: Notice of the designation of three new...

  16. Matching Derived Functionally-Same Stimulus Relations: Equivalence-Equivalence and Classical Analogies

    ERIC Educational Resources Information Center

    Carpentier, Franck; Smeets, Paul M.; Barnes-Holmes, Dermot; Stewart, Ian

    2004-01-01

    Previous studies have shown that, after being trained on A-B and A-C matching tasks, subjects match not only functionally-same B and C stimuli (stimulus equivalence), but also BC compounds with same-class elements and BC compounds with different-class elements (equivalence-equivalence). Similar performances are required in classical analogies (a :…

  17. Algebraic method for finding equivalence groups

    NASA Astrophysics Data System (ADS)

    Bihlo, Alexander; Dos Santos Cardoso-Bihlo, Elsa; Popovych, Roman O.

    2015-06-01

    The algebraic method for computing the complete point symmetry group of a system of differential equations is extended to finding the complete equivalence group of a class of such systems. The extended method uses the knowledge of the corresponding equivalence algebra. Two versions of the method are presented, where the first involves the automorphism group of this algebra and the second is based on a list of its megaideals. We illustrate the megaideal-based version of the method with the computation of the complete equivalence group of a class of nonlinear wave equations with applications in nonlinear elasticity.

  18. Relating equivalence relations to equivalence relations: A relational framing model of complex human functioning

    PubMed Central

    Barnes, Dermot; Hegarty, Neil; Smeets, Paul M.

    1997-01-01

    The current study aimed to develop a behavior-analytic model of analogical reasoning. In Experiments 1 and 2 subjects (adults and children) were trained and tested for the formation of four, three-member equivalence relations using a delayed matching-to-sample procedure. All subjects (Experiments 1 and 2) were exposed to tests that examined relations between equivalence and non-equivalence relations. For example, on an equivalence-equivalence relation test, the complex sample B1/C1 and the two complex comparisons B3/C3 and B3/C4 were used, and on a nonequivalence-nonequivalence relation test the complex sample B1/C2 was presented with the same two comparisons. All subjects consistently related equivalence relations to equivalence relations and nonequivalence relations to nonequivalence relations (e.g., picked B3/C3 in the presence of B1/C1 and picked B3/C4 in the presence of B1/C2). In Experiment 3, the equivalence responding, the equivalence-equivalence responding, and the nonequivalence-nonequivalence responding was successfully brought under contextual control. Finally, it was shown that the contextual cues could function successfully as comparisons, and the complex samples and comparisons could function successfully as contextual cues and samples, respectively. These data extend the equivalence paradigm and contribute to a behaviour-analytic interpretation of analogical reasoning and complex human functioning, in general. PMID:22477120

  19. Absorbed Dose and Dose Equivalent Calculations for Modeling Effective Dose

    NASA Technical Reports Server (NTRS)

    Welton, Andrew; Lee, Kerry

    2010-01-01

    While in orbit, Astronauts are exposed to a much higher dose of ionizing radiation than when on the ground. It is important to model how shielding designs on spacecraft reduce radiation effective dose pre-flight, and determine whether or not a danger to humans is presented. However, in order to calculate effective dose, dose equivalent calculations are needed. Dose equivalent takes into account an absorbed dose of radiation and the biological effectiveness of ionizing radiation. This is important in preventing long-term, stochastic radiation effects in humans spending time in space. Monte carlo simulations run with the particle transport code FLUKA, give absorbed and equivalent dose data for relevant shielding. The shielding geometry used in the dose calculations is a layered slab design, consisting of aluminum, polyethylene, and water. Water is used to simulate the soft tissues that compose the human body. The results obtained will provide information on how the shielding performs with many thicknesses of each material in the slab. This allows them to be directly applicable to modern spacecraft shielding geometries.

  20. REFractions: The Representing Equivalent Fractions Game

    ERIC Educational Resources Information Center

    Tucker, Stephen I.

    2014-01-01

    Stephen Tucker presents a fractions game that addresses a range of fraction concepts including equivalence and computation. The REFractions game also improves students' fluency with representing, comparing and adding fractions.

  1. SUPPORT FOR REFERENCE AND EQUIVALENCY PROGRAM

    EPA Science Inventory

    Federal Reference Methods (FRMs) and Federal Equivalent Methods (FEMs) form the backbone of the EPA's national monitoring strategy. They are the measurement methodologies that define attainment of a National Ambient Air Quality Standard (NAAQS). As knowledge and technology adva...

  2. Distinguishing Provenance Equivalence of Earth Science Data

    NASA Technical Reports Server (NTRS)

    Tilmes, Curt; Yesha, Ye; Halem, M.

    2010-01-01

    Reproducibility of scientific research relies on accurate and precise citation of data and the provenance of that data. Earth science data are often the result of applying complex data transformation and analysis workflows to vast quantities of data. Provenance information of data processing is used for a variety of purposes, including understanding the process and auditing as well as reproducibility. Certain provenance information is essential for producing scientifically equivalent data. Capturing and representing that provenance information and assigning identifiers suitable for precisely distinguishing data granules and datasets is needed for accurate comparisons. This paper discusses scientific equivalence and essential provenance for scientific reproducibility. We use the example of an operational earth science data processing system to illustrate the application of the technique of cascading digital signatures or hash chains to precisely identify sets of granules and as provenance equivalence identifiers to distinguish data made in an an equivalent manner.

  3. The endotopism semigroups of an equivalence relation

    SciTech Connect

    Zhuchok, Yu V; Toichkina, E A

    2014-05-31

    In this work we investigate six types of endotopism semigroups for a given equivalence relation. Necessary and sufficient conditions for the existence of all such endotopisms are presented. Conditions for the regularity and coregularity of each of the endotopism semigroups of a given type are established. The notion of the endotype of a binary relation with respect to its endotopisms is introduced and the endotype of an arbitrary equivalence relation is calculated. Bibliography: 26 titles.

  4. Dark matter and the equivalence principle

    NASA Technical Reports Server (NTRS)

    Frieman, Joshua A.; Gradwohl, Ben-Ami

    1993-01-01

    A survey is presented of the current understanding of dark matter invoked by astrophysical theory and cosmology. Einstein's equivalence principle asserts that local measurements cannot distinguish a system at rest in a gravitational field from one that is in uniform acceleration in empty space. Recent test-methods for the equivalence principle are presently discussed as bases for testing of dark matter scenarios involving the long-range forces between either baryonic or nonbaryonic dark matter and ordinary matter.

  5. Equivalence Relations, Contextual Control, and Naming

    PubMed Central

    Randell, Tom; Remington, Bob

    2006-01-01

    This paper reports two experiments that investigated the role of verbal behavior in the emergence and generalization of contextually controlled equivalence classes. During both experiments, participants were trained with two different combinations of the same easily nameable, yet formally unrelated, pictorial stimuli. Match-to-sample baselines for eight four-member classes were established under the contextual control of two colors. In the presence of one color, conditional relations were established between stimuli whose normative names rhymed. In the presence of the other color, conditional relations were established between stimuli whose normative names did not rhyme. Although, during Experiment 1, all participants demonstrated equivalence classes involving rhyming stimuli, none demonstrated the formation of nonrhyme equivalence classes. To investigate this finding, Experiment 2 evaluated whether participants would demonstrate both rhyme and nonrhyme equivalence classes given more extensive exposure to the experimental contingencies. All participants demonstrated contextually controlled rhyme and nonrhyme equivalence classes, although rhyme classes were demonstrated with greater facility than nonrhyme classes. Results indicate that visual stimuli are named, that verbal bases for stimulus classification can affect the emergence of contextually controlled equivalence classes, and that untrained contextually controlled conditional discriminations involving novel stimuli can emerge on the basis of participants' verbal behavior. PMID:17191757

  6. Validation of artificial skin equivalents as in vitro testing systems

    NASA Astrophysics Data System (ADS)

    Schmitt, Robert; Marx, Ulrich; Walles, Heike; Schober, Lena

    2011-03-01

    With the increasing complexity of the chemical composition of pharmaceuticals, cosmetics and everyday substances, the awareness of potential health issues and long term damages for humanoid organs is shifting into focus. Artificial in vitro testing systems play an important role in providing reliable test conditions and replacing precarious animal testing. Especially artificial skin equivalents ASEs are used for a broad spectrum of studies like penetration, irritation and corrosion of substances. One major challenge in tissue engineering is the qualification of each individual ASE as in vitro testing system. Due to biological fluctuations, the stratum corneum hornified layer of some ASEs may not fully develop or other defects might occur. For monitoring these effects we developed an fully automated Optical Coherence Tomography device. Here, we present different methods to characterize and evaluate the quality of the ASEs based on image and data processing of OCT B-scans. By analysing the surface structure, defects, like cuts or tears, are detectable. A further indicator for the quality of the ASE is the morphology of the tissue. This allows to determine if the skin model has reached the final growth state. We found, that OCT is a well suited technology for automatically characterizing artificial skin equivalents and validating the application as testing system.

  7. Natural equivalents of thermal gradient experiments

    NASA Astrophysics Data System (ADS)

    Rodríguez, Carmen; Geyer, Adelina; Castro, Antonio; Villaseñor, Antonio

    2015-06-01

    Crystallization experiments using the intrinsic thermal gradient in 10 mm length capsules loaded in piston-cylinder assemblies were used to investigate silicic magma crystallization. The application of experimental results to natural environments requires the scaling of physical parameters of petrological interest. Therefore, we propose here a comparative study between thermal gradients and numerical simulations of natural magma chambers. We use the Finite Element method to calculate thermal profiles across a cooling silicic magma chamber. These numerical profiles are compared with the intrinsic thermal structure of half-inch, piston-cylinder assemblies at 500 MPa. It is concluded that a set of varied magma chamber geometries and/or distinct stages of their cooling history can approach the intrinsic thermal structure of laboratory experiments. Once the thermal properties for magma and its host rock are fixed, the experimental-numerical approach is mostly dependent on the volume and aspect ratio of the magma chamber. Our results indicate, for instance, that a 10 mm length capsule with a thermal gradient of 40 °C/mm (from 1100 to 700 °C) may represent a 150-1100 m wide portion of a cooling magma chamber of 10-20 km diameter and 2-10 km height, emplaced at a depth of 18 km. Additional possible scenarios are represented by larger magma chambers, up to 30 km diameter, in which the experimental thermal gradient can represent a 150-3700 m-thin-section of the large igneous bodies.

  8. The New Wind Chill Equivalent Temperature Chart.

    NASA Astrophysics Data System (ADS)

    Osczevski, Randall; Bluestein, Maurice

    2005-10-01

    The formula used in the U.S. and Canada to express the combined effect of wind and low temperature on how cold it feels was changed in November 2001. Many had felt that the old formula for equivalent temperature, derived in the 1960s from Siple and Passel's flawed but quite useful Wind Chill Index, unnecessarily exaggerated the severity of the weather. The new formula is based on a mathematical model of heat flow from the upwind side of a head-sized cylinder moving at walking speed into the wind. The paper details the assumptions that were made in generating the new wind chill charts. It also points out weaknesses in the concept of wind chill equivalent temperature, including its steady-state character and a seemingly paradoxical effect of the internal thermal resistance of the cylinder on comfort and equivalent temperature. Some improvements and alternatives are suggested.

  9. Equivalent magnetization over the World Ocean

    NASA Astrophysics Data System (ADS)

    Dyment, J.; Hamoudi, M.; Choi, Y.; Thebault, E.; Quesnel, Y.; Roest, W. R.; Lesur, V.

    2012-12-01

    In another presentation (Hamoudi et al., this meeting), we present the construction of a new candidate for the World Digital Magnetic Anomaly Map (WDMAM) over oceanic areas. This map is based on: (a) a more realistic forward modeling of the marine magnetic anomalies which includes remanent magnetization vectors taking into account the age and motion of the oceanic lithosphere; (b) evaluation of the equivalent magnetization by comparison of the synthetic and observed anomalies along ship tracks; and (c) adjustment of the synthetic anomaly maps using this equivalent magnetization prior to merging with the observed anomalies. A by-product of this approach is a global distribution of equivalent magnetization over the World's Ocean. Note that, because no global basement map exists for the oceanic areas, we assume a uniform, 5 km-deep and 1 km-thick magnetized layer for the forward model. The resulting equivalent magnetization is therefore relative to this over-simplistic magnetic source. A first observation is that, within the hypotheses of the forward model, the average equivalent magnetization is about 3 A/m, a value which compares well with the Natural Remanent Magnetization (NRM) measured on ancient basalt samples. As expected, the mid-ocean ridges are marked by stronger equivalent magnetizations, an observation which reflects both the stronger NRM measured at ridge axes and their shallower bathymetry (not taken into account in our forward model). More interesting is the observation of significant along-axis variations. In the North Atlantic Ocean, the Kolbeinsey and Reykjanes ridges around Iceland are marked by a very strong equivalent magnetization and the Azores Plateau by a strong one as well.. Again this may reflect the combined effect of shallower seafloor, thicker and/or more magnetized basaltic layer at hotspots. In contrast, the areas between 45 and 55°N and between 0 and 10°N (Equatorial FZ) correspond to a weak equivalent magnetization. Further south

  10. Equivalent source current formulation in impedance tomography

    NASA Astrophysics Data System (ADS)

    Ilmoniemi, Risto J.; Ahlfors, Seppo P.

    1994-04-01

    Changes in the conductivity distribution of a body modify the electromagnetic field due to injected current in the same way as an equivalent source current distribution J(sup eq)(r) does. In the limit of small perturbations, it is shown that J(sup eq)(r) = Sigma(sup 1)(r)E(sup 0)(r), where Sigma(sup 1)(r) is a deviation in the conductivity and E(sup 0)(r) is the non-perturbed electric field. A model experiment demonstrates how a conductivity anomaly can be located using the minimum-norm estimate of the equivalent currents. The minimum-norm solution for small perturbation Sigma(sup 1)(r) is derived as well. The equivalent-source formulation allows the direct application of biomagnetic and bioelectric source-determination methods to conductivity imaging.

  11. Electrophysiological Correlates of Stimulus Equivalence Processes

    PubMed Central

    Haimson, Barry; Wilkinson, Krista M; Rosenquist, Celia; Ouimet, Carolyn; McIlvane, William J

    2009-01-01

    Research reported here concerns neural processes relating to stimulus equivalence class formation. In Experiment 1, two types of word pairs were presented successively to normally capable adults. In one type, the words had related usage in English (e.g., uncle, aunt). In the other, the two words were not typically related in their usage (e.g., wrist, corn). For pairs of both types, event-related cortical potentials were recorded during and immediately after the presentation of the second word. The obtained waveforms differentiated these two types of pairs. For the unrelated pairs, the waveforms were significantly more negative about 400 ms after the second word was presented, thus replicating the “N400” phenomenon of the cognitive neuroscience literature. In addition, there was a strong positive-tending wave form difference post-stimulus presentation (peaked at about 500 ms) that also differentiated the unrelated from related stimulus pairs. In Experiment 2, the procedures were extended to study arbitrary stimulus–stimulus relations established via matching-to-sample training. Participants were experimentally naïve adults. Sample stimuli (Set A) were trigrams, and comparison stimuli (Sets B, C, D, E, and F) were nonrepresentative forms. Behavioral tests evaluated potentially emergent equivalence relations (i.e., BD, DF, CE, etc.). All participants exhibited classes consistent with the arbitrary matching training. They were also exposed also to an event-related potential procedure like that used in Experiment 1. Some received the ERP procedure before equivalence tests and some after. Only those participants who received ERP procedures after equivalence tests exhibited robust N400 differentiation initially. The positivity observed in Experiment 1 was absent for all participants. These results support speculations that equivalence tests may provide contextual support for the formation of equivalence classes including those that emerge gradually during testing

  12. Equivalence between XY and dimerized models

    NASA Astrophysics Data System (ADS)

    Campos Venuti, Lorenzo; Roncaglia, Marco

    2010-06-01

    The spin-1/2 chain with XY anisotropic coupling in the plane and the XX isotropic dimerized chain are shown to be equivalent in the bulk. For finite systems, we prove that the equivalence is exact in given parity sectors, after taking care of the precise boundary conditions. The proof is given constructively by finding unitary transformations that map the models onto each other. Moreover, we considerably generalized our mapping and showed that even in the case of fully site-dependent couplings the XY chain can be mapped onto an XX model. This result has potential application in the study of disordered systems.

  13. Tissue types (image)

    MedlinePlus

    ... are 4 basic types of tissue: connective tissue, epithelial tissue, muscle tissue, and nervous tissue. Connective tissue supports ... binds them together (bone, blood, and lymph tissues). Epithelial tissue provides a covering (skin, the linings of the ...

  14. Stability of functional equivalence and stimulus equivalence: effects of baseline reversals.

    PubMed Central

    Wirth, Oliver; Chase, Philip N

    2002-01-01

    Functional equivalence and stimulus equivalence classes were established, reversed, and tested for stability with college students. Functional stimulus classes were established using a task in which students were trained to say nonsense words in the presence of arbitrarily assigned sets of symbols. Computer-controlled speech-recognition technology was used to record and analyze students' vocal responses for accuracy. After the establishment of stimulus classes was demonstrated with a transfer-of-function test, the effects of reversing selected baseline simple discriminations were assessed during an additional transfer-of-function test and a follow-up test that occurred several weeks later. With the same students, stimulus equivalence classes were established and demonstrated with computerized matching-to-sample procedures. The effects of reversing selected baseline conditional discriminations also were assessed during a postreversal equivalence test and a follow-up test. Both functional stimulus classes and stimulus equivalence were sensitive to contingency reversals, but the reversals with stimulus equivalence closses affected stimulus class organization whereas reversals with functional stimulus classes did not. Follow-up performances were largely consistent with the original baseline contingencies. The similarities and differences between stimulus equivalence and functional equivalence are related to the specific contingencies that select responding in the presence of the stimuli that form the classes. PMID:11831781

  15. High School Equivalency Testing in Arizona. Forum: Responding to Changes in High School Equivalency Testing

    ERIC Educational Resources Information Center

    Hart, Sheryl

    2015-01-01

    For decades, the state of Arizona has used the General Educational Development (GED) Test to award the Arizona High School Equivalency (HSE) Diploma, as the GED Test was the only test available, recognized and accepted in the United States as the measure by which adults could demonstrate the educational attainment equivalent to high school…

  16. Space radiation protection: comparison of effective dose to bone marrow dose equivalent.

    PubMed

    Hoff, Jennifer L; Townsend, Lawrence W; Zapp, E Neal

    2002-12-01

    In many instances, bone marrow dose equivalents averaged over the entire body have been used as a surrogate for whole-body dose equivalents in space radiation protection studies. However, career radiation limits for space missions are expressed as effective doses. This study compares calculations of effective doses to average bone marrow dose equivalents for several large solar particle events (SPEs) and annual galactic cosmic ray (GCR) spectra, in order to examine the suitability of substituting bone marrow dose equivalents for effective doses. Organ dose equivalents are computed for all radiosensitive organs listed in NCRP Report 116 using the BRYNTRN and HZETRN space radiation transport codes and the Computerized Anatomical Man (CAM) model. These organ dose equivalents are then weighted with the appropriate tissue weighting factors to obtain effective doses. Various thicknesses of aluminum shielding, which are representative of nominal spacecraft and SPE storm shelter configurations, are used in the analyses. For all SPE configurations, the average bone marrow dose equivalent is considerably less than the calculated effective dose. For comparisons of the GCR, there is less than a ten percent difference between the two methods. In all cases, the gonads made up the largest percentage of the effective dose. PMID:12793744

  17. 21 CFR 26.9 - Equivalence determination.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 1 2011-04-01 2011-04-01 false Equivalence determination. 26.9 Section 26.9 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL MUTUAL RECOGNITION OF PHARMACEUTICAL GOOD MANUFACTURING PRACTICE REPORTS, MEDICAL DEVICE QUALITY SYSTEM AUDIT...

  18. 33 CFR 157.07 - Equivalents.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... CFR 30.15-1, of a design or an equipment to fulfill a requirement in this part, except an operational... 33 Navigation and Navigable Waters 2 2011-07-01 2011-07-01 false Equivalents. 157.07 Section 157.07 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED)...

  19. 33 CFR 157.07 - Equivalents.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... CFR 30.15-1, of a design or an equipment to fulfill a requirement in this part, except an operational... 33 Navigation and Navigable Waters 2 2012-07-01 2012-07-01 false Equivalents. 157.07 Section 157.07 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED)...

  20. 33 CFR 157.07 - Equivalents.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... CFR 30.15-1, of a design or an equipment to fulfill a requirement in this part, except an operational... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Equivalents. 157.07 Section 157.07 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED)...

  1. 33 CFR 157.07 - Equivalents.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... CFR 30.15-1, of a design or an equipment to fulfill a requirement in this part, except an operational... 33 Navigation and Navigable Waters 2 2014-07-01 2014-07-01 false Equivalents. 157.07 Section 157.07 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED)...

  2. 33 CFR 157.07 - Equivalents.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... CFR 30.15-1, of a design or an equipment to fulfill a requirement in this part, except an operational... 33 Navigation and Navigable Waters 2 2013-07-01 2013-07-01 false Equivalents. 157.07 Section 157.07 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED)...

  3. 21 CFR 26.39 - Equivalence assessment.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... RECOGNITION OF PHARMACEUTICAL GOOD MANUFACTURING PRACTICE REPORTS, MEDICAL DEVICE QUALITY SYSTEM AUDIT REPORTS, AND CERTAIN MEDICAL DEVICE PRODUCT EVALUATION REPORTS: UNITED STATES AND THE EUROPEAN COMMUNITY Specific Sector Provisions for Medical Devices § 26.39 Equivalence assessment. (a) In the final 6 months...

  4. 21 CFR 26.39 - Equivalence assessment.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... RECOGNITION OF PHARMACEUTICAL GOOD MANUFACTURING PRACTICE REPORTS, MEDICAL DEVICE QUALITY SYSTEM AUDIT REPORTS, AND CERTAIN MEDICAL DEVICE PRODUCT EVALUATION REPORTS: UNITED STATES AND THE EUROPEAN COMMUNITY Specific Sector Provisions for Medical Devices § 26.39 Equivalence assessment. (a) In the final 6 months...

  5. HOW TO PASS HIGH SCHOOL EQUIVALENCY EXAMINATION.

    ERIC Educational Resources Information Center

    KLAGSBRUN, FRANCINE, ED.

    ORGANIZED INTO A FIVE-DAY STUDY PLAN, ALLOWING ONE DAY'S STUDY TO EACH PART OF THE EQUIVALENCY EXAMINATION (SPELLING AND GRAMMAR, SOCIAL STUDIES, SCIENCE, LITERATURE, AND MATHEMATICS), THIS BOOK PROVIDES SAMPLE TESTS AND ANSWER SHEETS, A TEST SCORE RECORD AND SELF EVALUATION PROFILE, AND SUPPLEMENTARY TESTS FOR EACH SUBJECT. THE EXAMINEE CAN ORDER…

  6. CP Violation, Neutral Currents, and Weak Equivalence

    DOE R&D Accomplishments Database

    Fitch, V. L.

    1972-03-23

    Within the past few months two excellent summaries of the state of our knowledge of the weak interactions have been presented. Correspondingly, we will not attempt a comprehensive review but instead concentrate this discussion on the status of CP violation, the question of the neutral currents, and the weak equivalence principle.

  7. Procedures for Determining the Equivalence of Measures.

    ERIC Educational Resources Information Center

    Dunivant, Noel

    Eight different methods are reviewed for determining whether two or more tests are equivalent measures. These methods vary in restrictiveness from the Wilks-Votaw test of compound symmetry (which requires that all means, variances, and covariances are equal), to Joreskog's theory of congeneric tests (which requires only that the tests are measures…

  8. 33 CFR 67.01-30 - Equivalents.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Equivalents. 67.01-30 Section 67.01-30 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY AIDS TO NAVIGATION AIDS TO NAVIGATION ON ARTIFICIAL ISLANDS AND FIXED STRUCTURES General Requirements §...

  9. 33 CFR 67.01-30 - Equivalents.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false Equivalents. 67.01-30 Section 67.01-30 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY AIDS TO NAVIGATION AIDS TO NAVIGATION ON ARTIFICIAL ISLANDS AND FIXED STRUCTURES General Requirements §...

  10. 33 CFR 67.01-30 - Equivalents.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 1 2012-07-01 2012-07-01 false Equivalents. 67.01-30 Section 67.01-30 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY AIDS TO NAVIGATION AIDS TO NAVIGATION ON ARTIFICIAL ISLANDS AND FIXED STRUCTURES General Requirements §...

  11. 33 CFR 67.01-30 - Equivalents.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 1 2014-07-01 2014-07-01 false Equivalents. 67.01-30 Section 67.01-30 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY AIDS TO NAVIGATION AIDS TO NAVIGATION ON ARTIFICIAL ISLANDS AND FIXED STRUCTURES General Requirements §...

  12. 33 CFR 67.01-30 - Equivalents.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 1 2013-07-01 2013-07-01 false Equivalents. 67.01-30 Section 67.01-30 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY AIDS TO NAVIGATION AIDS TO NAVIGATION ON ARTIFICIAL ISLANDS AND FIXED STRUCTURES General Requirements §...

  13. Spin-Gravity Interactions and Equivalence Principle

    NASA Astrophysics Data System (ADS)

    Obukhov, Yu. N.; Silenko, A. J.; Teryaev, O. V.

    2016-02-01

    The spin-gravity interactions imply the new manifestation of the equivalence principle leading to the absence of gravitoelectric and anomalous gravitomagnetic moments for fermions. This property is still valid in the presence of the space-time torsion due to the covariance arguments. The experimental bounds for the torsion, which may be extracted from modern co-magnetometer experiments, are discussed.

  14. 46 CFR 175.540 - Equivalents.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... Safety Management (ISM) Code (IMO Resolution A.741(18)) for the purpose of determining that an equivalent safety management system is in place on board a vessel. The Commandant will consider the size and..., appliance, apparatus, equipment, calculation, information, or test, which provides a level of...

  15. 46 CFR 175.540 - Equivalents.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... Safety Management (ISM) Code (IMO Resolution A.741(18)) for the purpose of determining that an equivalent safety management system is in place on board a vessel. The Commandant will consider the size and..., appliance, apparatus, equipment, calculation, information, or test, which provides a level of...

  16. 46 CFR 175.540 - Equivalents.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... Safety Management (ISM) Code (IMO Resolution A.741(18)) for the purpose of determining that an equivalent safety management system is in place on board a vessel. The Commandant will consider the size and..., appliance, apparatus, equipment, calculation, information, or test, which provides a level of...

  17. Electrophysiological Correlates of Stimulus Equivalence Processes

    ERIC Educational Resources Information Center

    Haimson, Barry; Wilkinson, Krista M.; Rosenquist, Celia; Ouimet, Carolyn; McIlvane, William J.

    2009-01-01

    Research reported here concerns neural processes relating to stimulus equivalence class formation. In Experiment 1, two types of word pairs were presented successively to normally capable adults. In one type, the words had related usage in English (e.g., uncle, aunt). In the other, the two words were not typically related in their usage (e.g.,…

  18. Are Letter Detection and Proofreading Tasks Equivalent?

    ERIC Educational Resources Information Center

    Saint-Aubin, Jean; Losier, Marie-Claire; Roy, Macha; Lawrence, Mike

    2015-01-01

    When readers search for misspellings in a proofreading task or for a letter in a letter detection task, they are more likely to omit function words than content words. However, with misspelled words, previous findings for the letter detection task were mixed. In two experiments, the authors tested the functional equivalence of both tasks. Results…

  19. 33 CFR 155.120 - Equivalents.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 2 2012-07-01 2012-07-01 false Equivalents. 155.120 Section 155.120 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) POLLUTION OIL OR HAZARDOUS MATERIAL POLLUTION PREVENTION REGULATIONS FOR VESSELS General § 155.120...

  20. 33 CFR 155.120 - Equivalents.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 2 2013-07-01 2013-07-01 false Equivalents. 155.120 Section 155.120 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) POLLUTION OIL OR HAZARDOUS MATERIAL POLLUTION PREVENTION REGULATIONS FOR VESSELS General § 155.120...

  1. 33 CFR 155.120 - Equivalents.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 2 2014-07-01 2014-07-01 false Equivalents. 155.120 Section 155.120 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) POLLUTION OIL OR HAZARDOUS MATERIAL POLLUTION PREVENTION REGULATIONS FOR VESSELS General § 155.120...

  2. Reading adn Auditory-Visual Equivalences

    ERIC Educational Resources Information Center

    Sidman, Murray

    1971-01-01

    A retarded boy, unable to read orally or with comprehension, was taught to match spoken to printed words and was then capable of reading comprehension (matching printed words to picture) and oral reading (naming printed words aloud), demonstrating that certain learned auditory-visual equivalences are sufficient prerequisites for reading…

  3. 21 CFR 26.6 - Equivalence assessment.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 1 2012-04-01 2012-04-01 false Equivalence assessment. 26.6 Section 26.6 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES GENERAL MUTUAL RECOGNITION OF PHARMACEUTICAL GOOD MANUFACTURING PRACTICE REPORTS, MEDICAL DEVICE QUALITY SYSTEM AUDIT...

  4. Pseudo-Equivalent Groups and Linking

    ERIC Educational Resources Information Center

    Haberman, Shelby J.

    2015-01-01

    Adjustment by minimum discriminant information provides an approach to linking test forms in the case of a nonequivalent groups design with no satisfactory common items. This approach employs background information on individual examinees in each administration so that weighted samples of examinees form pseudo-equivalent groups in the sense that…

  5. AN UPDATE ON TECHNOLOGIES SEEKING PFRP EQUIVALENCY

    EPA Science Inventory

    This presentation will: 1) Review the mandate of the Pathogen Equivalency Committee (PEC), 2) Review the PEC's current membership (of 10), 3) Discuss how a typical application is evaluated, 4) Note where information can be found by those interested in applying to the PEC, 5) List...

  6. Structural Equivalence in a Journal Network.

    ERIC Educational Resources Information Center

    Doreian, Patrick; Fararo, Thomas J.

    1985-01-01

    Techniques used in contemporary social network analysis are applied to citation data for a network of journals from three time periods--1970/71, 1975/76, 1980/81. Blocks or positions in journal network based on structural equivalence correspond closely to categorization by aims and objectives. Hypotheses concerning journal networks are advanced.…

  7. 33 CFR 155.120 - Equivalents.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 2 2011-07-01 2011-07-01 false Equivalents. 155.120 Section 155.120 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) POLLUTION OIL OR HAZARDOUS MATERIAL POLLUTION PREVENTION REGULATIONS FOR VESSELS General § 155.120...

  8. 36 CFR 1194.5 - Equivalent facilitation.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 36 Parks, Forests, and Public Property 3 2012-07-01 2012-07-01 false Equivalent facilitation. 1194.5 Section 1194.5 Parks, Forests, and Public Property ARCHITECTURAL AND TRANSPORTATION BARRIERS COMPLIANCE BOARD ELECTRONIC AND INFORMATION TECHNOLOGY ACCESSIBILITY STANDARDS General § 1194.5...

  9. 36 CFR 1192.2 - Equivalent facilitation.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... the procedure set forth in 49 CFR 37.7. ... 36 Parks, Forests, and Public Property 3 2012-07-01 2012-07-01 false Equivalent facilitation. 1192.2 Section 1192.2 Parks, Forests, and Public Property ARCHITECTURAL AND TRANSPORTATION...

  10. 36 CFR 1192.2 - Equivalent facilitation.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... the procedure set forth in 49 CFR 37.7. ... 36 Parks, Forests, and Public Property 3 2011-07-01 2011-07-01 false Equivalent facilitation. 1192.2 Section 1192.2 Parks, Forests, and Public Property ARCHITECTURAL AND TRANSPORTATION...

  11. 36 CFR 1194.5 - Equivalent facilitation.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 36 Parks, Forests, and Public Property 3 2011-07-01 2011-07-01 false Equivalent facilitation. 1194.5 Section 1194.5 Parks, Forests, and Public Property ARCHITECTURAL AND TRANSPORTATION BARRIERS COMPLIANCE BOARD ELECTRONIC AND INFORMATION TECHNOLOGY ACCESSIBILITY STANDARDS General § 1194.5...

  12. 36 CFR 1192.2 - Equivalent facilitation.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... the procedure set forth in 49 CFR 37.7. ... 36 Parks, Forests, and Public Property 3 2014-07-01 2014-07-01 false Equivalent facilitation. 1192.2 Section 1192.2 Parks, Forests, and Public Property ARCHITECTURAL AND TRANSPORTATION...

  13. 36 CFR 1192.2 - Equivalent facilitation.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... the procedure set forth in 49 CFR 37.7. ... 36 Parks, Forests, and Public Property 3 2010-07-01 2010-07-01 false Equivalent facilitation. 1192.2 Section 1192.2 Parks, Forests, and Public Property ARCHITECTURAL AND TRANSPORTATION...

  14. 36 CFR 1194.5 - Equivalent facilitation.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 36 Parks, Forests, and Public Property 3 2013-07-01 2012-07-01 true Equivalent facilitation. 1194.5 Section 1194.5 Parks, Forests, and Public Property ARCHITECTURAL AND TRANSPORTATION BARRIERS COMPLIANCE BOARD ELECTRONIC AND INFORMATION TECHNOLOGY ACCESSIBILITY STANDARDS General § 1194.5...

  15. 36 CFR 1192.2 - Equivalent facilitation.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... the procedure set forth in 49 CFR 37.7. ... 36 Parks, Forests, and Public Property 3 2013-07-01 2012-07-01 true Equivalent facilitation. 1192.2 Section 1192.2 Parks, Forests, and Public Property ARCHITECTURAL AND TRANSPORTATION...

  16. 36 CFR 1194.5 - Equivalent facilitation.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 36 Parks, Forests, and Public Property 3 2010-07-01 2010-07-01 false Equivalent facilitation. 1194.5 Section 1194.5 Parks, Forests, and Public Property ARCHITECTURAL AND TRANSPORTATION BARRIERS COMPLIANCE BOARD ELECTRONIC AND INFORMATION TECHNOLOGY ACCESSIBILITY STANDARDS General § 1194.5...

  17. 36 CFR 1194.5 - Equivalent facilitation.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 36 Parks, Forests, and Public Property 3 2014-07-01 2014-07-01 false Equivalent facilitation. 1194.5 Section 1194.5 Parks, Forests, and Public Property ARCHITECTURAL AND TRANSPORTATION BARRIERS COMPLIANCE BOARD ELECTRONIC AND INFORMATION TECHNOLOGY ACCESSIBILITY STANDARDS General § 1194.5...

  18. 20 CFR 404.1526 - Medical equivalence.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 20 Employees' Benefits 2 2012-04-01 2012-04-01 false Medical equivalence. 404.1526 Section 404.1526 Employees' Benefits SOCIAL SECURITY ADMINISTRATION FEDERAL OLD-AGE, SURVIVORS AND DISABILITY INSURANCE (1950- ) Determining Disability and Blindness Medical Considerations § 404.1526...

  19. 20 CFR 404.1526 - Medical equivalence.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 20 Employees' Benefits 2 2010-04-01 2010-04-01 false Medical equivalence. 404.1526 Section 404.1526 Employees' Benefits SOCIAL SECURITY ADMINISTRATION FEDERAL OLD-AGE, SURVIVORS AND DISABILITY INSURANCE (1950- ) Determining Disability and Blindness Medical Considerations § 404.1526...

  20. 20 CFR 404.1526 - Medical equivalence.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 20 Employees' Benefits 2 2011-04-01 2011-04-01 false Medical equivalence. 404.1526 Section 404.1526 Employees' Benefits SOCIAL SECURITY ADMINISTRATION FEDERAL OLD-AGE, SURVIVORS AND DISABILITY INSURANCE (1950- ) Determining Disability and Blindness Medical Considerations § 404.1526...

  1. 20 CFR 404.1526 - Medical equivalence.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 20 Employees' Benefits 2 2014-04-01 2014-04-01 false Medical equivalence. 404.1526 Section 404.1526 Employees' Benefits SOCIAL SECURITY ADMINISTRATION FEDERAL OLD-AGE, SURVIVORS AND DISABILITY INSURANCE (1950- ) Determining Disability and Blindness Medical Considerations § 404.1526...

  2. 20 CFR 404.1526 - Medical equivalence.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 20 Employees' Benefits 2 2013-04-01 2013-04-01 false Medical equivalence. 404.1526 Section 404.1526 Employees' Benefits SOCIAL SECURITY ADMINISTRATION FEDERAL OLD-AGE, SURVIVORS AND DISABILITY INSURANCE (1950- ) Determining Disability and Blindness Medical Considerations § 404.1526...

  3. Identifiability and Equivalence of GLLIRM Models

    ERIC Educational Resources Information Center

    Revuelta, Javier

    2009-01-01

    The generalized logit-linear item response model (GLLIRM) is a linearly constrained nominal categories model (NCM) that computes the scale and intercept parameters for categories as a weighted sum of basic parameters. This paper addresses the problems of the identifiability of the basic parameters and the equivalence between different GLLIRM…

  4. 46 CFR 175.540 - Equivalents.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... lifesaving appliance or arrangement as an equivalent if it has performance characteristics at least... IMO Resolution A. 520(13) (incorporated by reference, see 46 CFR 175.600); or (2) Has successfully... Safety Management (ISM) Code (IMO Resolution A.741(18)) for the purpose of determining that an...

  5. Equivalent weight of humic acid from peat

    USGS Publications Warehouse

    Pommer, A.M.; Breger, I.A.

    1960-01-01

    By means of discontinuous titration, the equivalent weight of humic acid isolated from a peat was found to increase from 144 to 183 between the third and fifty-second day after the humic acid was dissolved. Infra-red studies showed that the material had probably condensed with loss of carbonyl groups. ?? 1960.

  6. SUPPORT FOR USEPA'S PATHOGEN EQUIVALENCY COMMITTEE

    EPA Science Inventory

    This presentation will discuss recommended and new resources for the USEPA's Pathogen Equivalency Committee including: 1) Committee's creation in 1985 and its purpose 2) Drexel University Professor Chuck Haas' 2001 report (Assessment of the PEC Process) and its findings 3) NAS/NR...

  7. 7 CFR 1005.54 - Equivalent price.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 9 2011-01-01 2011-01-01 false Equivalent price. 1005.54 Section 1005.54 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing Agreements and Orders; Milk), DEPARTMENT OF AGRICULTURE MILK IN THE APPALACHIAN MARKETING AREA Order...

  8. 7 CFR 1005.54 - Equivalent price.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 9 2014-01-01 2013-01-01 true Equivalent price. 1005.54 Section 1005.54 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (MARKETING AGREEMENTS AND ORDERS; MILK), DEPARTMENT OF AGRICULTURE MILK IN THE APPALACHIAN MARKETING AREA Order...

  9. 7 CFR 1005.54 - Equivalent price.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 9 2012-01-01 2012-01-01 false Equivalent price. 1005.54 Section 1005.54 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing Agreements and Orders; Milk), DEPARTMENT OF AGRICULTURE MILK IN THE APPALACHIAN MARKETING AREA Order...

  10. 7 CFR 1005.54 - Equivalent price.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 9 2013-01-01 2013-01-01 false Equivalent price. 1005.54 Section 1005.54 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (MARKETING AGREEMENTS AND ORDERS; MILK), DEPARTMENT OF AGRICULTURE MILK IN THE APPALACHIAN MARKETING AREA Order...

  11. 33 CFR 155.120 - Equivalents.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Equivalents. 155.120 Section 155.120 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) POLLUTION OIL OR HAZARDOUS MATERIAL POLLUTION PREVENTION REGULATIONS FOR VESSELS General § 155.120...

  12. Water equivalence of various materials for clinical proton dosimetry by experiment and Monte Carlo simulation

    NASA Astrophysics Data System (ADS)

    Al-Sulaiti, Leena; Shipley, David; Thomas, Russell; Kacperek, Andrzej; Regan, Patrick; Palmans, Hugo

    2010-07-01

    The accurate conversion of dose to various materials used in clinical proton dosimetry to dose-to-water is based on fluence correction factors, accounting for attenuation of primary protons and production of secondary particles due to non-elastic nuclear interactions. This work aims to investigate the depth dose distribution and the fluence correction with respect to water or graphite at water equivalent depths (WED) in different target materials relevant for dosimetry such as polymethyl methacrylate (PMMA), graphite, A-150, aluminium and copper at 60 and 200 MeV. This was done through a comparison between Monte Carlo simulation using MCNPX 2.5.0, analytical model calculations and experimental measurements at Clatterbridge Centre of Oncology (CCO) in a 60 MeV modulated and un-modulated proton beam. MCNPX simulations indicated small fluence corrections for all materials with respect to graphite and water in 60 and 200 MeV except for aluminium. The analytical calculations showed an increase in the fluence correction factor to a few percent for all materials with respect to water at 200 MeV. The experimental measurements for 60 MeV un-modulated beam indicated a good agreement with MCNPX. For the modulated beam the fluence correction factor was found to be decreasing below unity by up to few percent with depth for aluminium and copper but almost constant and unity for A-150.

  13. Tissue Microdissection.

    PubMed

    Rabien, Anja; Kristiansen, Glen

    2016-01-01

    The new opportunities of modern assays of molecular biology can only be exploited fully if the results can be accurately correlated to the tissue phenotype under investigation. This is a general problem of non-in situ techniques, whereas results from in situ techniques are often difficult to quantify. The use of bulk tissue, which is not precisely characterized in terms of histology, has long been the basis for molecular analysis. It has, however, become apparent, that this simple approach is not sufficient for a detailed analysis of molecular alterations, which might be restricted to a specific tissue phenotype (e.g., tumor or normal tissue, stromal or epithelial cells). Microdissection is a method to provide minute amounts of histologically characterized tissues for molecular analysis with non-in situ techniques and has become an indispensable research tool. If tissue diversity is moderate and negligible, manual microdissection can be an easy and cost-efficient method of choice. In contrast, the advantage of laser microdissection is a very exact selection down to the level of a single cell, but often with a considerable time exposure to get enough material for the following analyses. The latter issue and the method of tissue preparation needed for laser microdissection are the main problems to solve if RNA, highly sensitive to degradation, shall be analyzed. This chapter focuses on optimized procedures for manual microdissection and laser microdissection to analyze RNA of malignant and nonmalignant prostate tissue. PMID:26667453

  14. Representing Identity and Equivalence for Scientific Data

    NASA Astrophysics Data System (ADS)

    Wickett, K. M.; Sacchi, S.; Dubin, D.; Renear, A. H.

    2012-12-01

    Matters of equivalence and identity are central to the stewardship of scientific data. In order to properly prepare for and manage the curation, preservation and sharing of digitally-encoded data, data stewards must be able to characterize and assess the relationships holding between data-carrying digital resources. However, identity-related questions about resources and their information content may not be straightforward to answer: for example, what exactly does it mean to say that two files contain the same data, but in different formats? Information content is frequently distinguished from particular representations, but there is no adequately developed shared understanding of what this really means and how the relationship between content and its representations hold. The Data Concepts group at the Center for Informatics Research in Science and Scholarship (CIRSS), University of Illinois at Urbana Champaign, is developing a logic-based framework of fundamental concepts related to scientific data to support curation and integration. One project goal is to develop precise accounts of information resources carrying the same data. We present two complementary conceptual models for information representation: the Basic Representation Model (BRM) and the Systematic Assertion Model (SAM). We show how these models provide an analytical account of digitally-encoded scientific data and a precise understanding of identity and equivalence. The Basic Representation Model identifies the core entities and relationships involved in representing information carried by digital objects. In BRM, digital objects are symbol structures that express propositional content, and stand in layered encoding relationships. For example, an RDF description may be serialized as either XML or N3, and those expressions in turn may be encoded as either UTF-8 or UTF-16 sequences. Defining this encoding stack reveals distinctions necessary for a precise account of identity and equivalence

  15. Modified Equivalent Circuit for Organic Solar Cells

    NASA Astrophysics Data System (ADS)

    Hossain, Nazmul

    In this work a newly fabricated organic solar cell based on a composite of fullerene derivative [6,6]-phenyl-C61 butyric acid methyl ester (PCBM) and regioregular poly (3-hexylthiophene) (P3HT) with an added interfacial layer of AgOx in between the PEDOT:PSS layer and the ITO layer is investigated. Previous equivalent circuit models are discussed and an equivalent circuit model is proposed for the fabricated device. Incorporation of the AgOx interfacial layer shows an increase in fill factor (by 33%) and power conversion efficiency (by 28%). Moreover proper correlation has been achieved between the experimental and simulated I-V plots. The simulation shows that device characteristics can be explained with accuracy by the proposed model.

  16. Scaling Laws for Hydrodynamically Equivalent Implosions

    NASA Astrophysics Data System (ADS)

    Murakami, Masakatsu

    2001-10-01

    The EPOC (equivalent physics of confinement) scenario for the proof of principle of high gain inertial confinement fusion is presented, where the key concept "hydrodynamically equivalent implosions" plays a crucial role. Scaling laws on the target and confinement parameters are derived by applying the Lie group analysis to the PDE (partially differential equations) chain of the hydrodynamic system. It turns out that the conventional scaling law based on adiabatic approximation significantly differs from one which takes such energy transport effect as electron heat conduction into account. Confinement plasma parameters of the hot spot such as the central temperature and the areal mass density at peak compression are obtained with a self-similar solution for spherical implosions.

  17. Anomalies, equivalence and renormalization of cosmological frames

    NASA Astrophysics Data System (ADS)

    Herrero-Valea, Mario

    2016-05-01

    We study the question of whether two frames of a given physical theory are equivalent or not in the presence of quantum corrections. By using field theory arguments, we claim that equivalence is broken in the presence of anomalous symmetries in one of the frames. This is particularized to the case of the relation between the Einstein and Jordan frames in scalar-tensor theories used to describe early Universe dynamics. Although in this case a regularization that cancels the anomaly exists, the renormalized theory always develops a nonvanishing contribution to the S matrix that is present only in the Jordan frame, promoting the different frames to different physical theories that must be UV completed in a different way.

  18. Are All Wrong FCI Answers Equivalent?

    NASA Astrophysics Data System (ADS)

    Dedic, Helena; Rosenfield, Steven; Lasry, Nathaniel

    2010-10-01

    The Force Concept Inventory (FCI) has been efficiently used to assess conceptual learning in mechanics. Each FCI question has one Newtonian answer and four wrong answers (distracters). Researchers and practitioners most frequently use measures of total score to assess learning. Yet, are all wrong answers equivalent? We conducted Latent Markov Chain Modeling (LMCM) analyses of all choices (right and wrong) on a subset of four FCI questions. LMCM assesses whether there are groups of students sharing similar patterns of responses. We infer that students sharing similar patterns also share similar reasoning. Our results show seven reasoning-groups. LMCM also computes probabilities of transition from one reasoning-group to another after instruction. Examining transitions between groups, we note a clear hierarchy. Groups at the top of the hierarchy are comprised of students that use Newtonian thinking more consistently but also choose certain wrong answers more frequently; suggesting that not all wrong answers are equivalent.

  19. Explosive materials equivalency, test methods and evaluation

    NASA Technical Reports Server (NTRS)

    Koger, D. M.; Mcintyre, F. L.

    1980-01-01

    Attention is given to concepts of explosive equivalency of energetic materials based on specific airblast parameters. A description is provided of a wide bandwidth high accuracy instrumentation system which has been used extensively in obtaining pressure time profiles of energetic materials. The object of the considered test method is to determine the maximum output from the detonation of explosive materials in terms of airblast overpressure and positive impulse. The measured pressure and impulse values are compared with known characteristics of hemispherical TNT data to determine the equivalency of the test material in relation to TNT. An investigation shows that meaningful comparisons between various explosives and a standard reference material such as TNT should be based upon the same parameters. The tests should be conducted under the same conditions.

  20. Minimal information to determine affine shape equivalence.

    PubMed

    Wagemans, J; Van Gool, L; Lamote, C; Foster, D H

    2000-04-01

    Participants judged the affine equivalence of 2 simultaneously presented 4-point patterns. Performance level (d') varied between 1.5 and 2.7, depending on the information available for solving the correspondence problem (insufficient in Experiment 1a, superfluous in Experiment 1b, and minimal in Experiments 1c, 2a, 2b) and on the exposure time (unlimited in Experiments 1 and 2a and 500 ms in Experiment 2b), but it did not vary much with the complexity of the affine transformation (rotation and slant in Experiment 1 and same plus tilt in Experiment 2). Performance in Experiment 3 was lower with 3-point patterns than with 4-point patterns, whereas blocking the trials according to the affine transformation parameters had little effect. Determining affine shape equivalence with minimal-information displays is based on a fast assessment of qualitatively or quasi-invariant properties such as convexity/ concavity, parallelism, and collinearity. PMID:10811156

  1. On equivalent resistance of electrical circuits

    NASA Astrophysics Data System (ADS)

    Kagan, Mikhail

    2015-01-01

    While the standard (introductory physics) way of computing the equivalent resistance of nontrivial electrical circuits is based on Kirchhoff's rules, there is a mathematically and conceptually simpler approach, called the method of nodal potentials, whose basic variables are the values of the electric potential at the circuit's nodes. In this paper, we review the method of nodal potentials and illustrate it using the Wheatstone bridge as an example. We then derive a closed-form expression for the equivalent resistance of a generic circuit, which we apply to a few sample circuits. The result unveils a curious interplay between electrical circuits, matrix algebra, and graph theory and its applications to computer science. The paper is written at a level accessible by undergraduate students who are familiar with matrix arithmetic. Additional proofs and technical details are provided in appendices.

  2. Satellite Test of the Equivalence Principle (STEP)

    NASA Technical Reports Server (NTRS)

    Worden, Paul

    1994-01-01

    This grant provided support for the STEP (Satellite Test of the Equivalence Principle) program between October 1991 and September 1993. STEP, previously supported by NASA under Grant NAG8-837 'A Satellite Test of the Equivalence Principle,' was selected by the European Space Agency for a Phase A study as a candidate for ESA's next medium size mission (M2). STEP was conceived as a joint NASA/ESA mission with equal participation by both agencies. ESA's contribution to the program would be the spacecraft; NASA would provide the launcher and half of the instrument, while the other half of the instrument would be provided by various European agencies. STEP was in competition with three other programs, INTEGRAL, PRISMA, and MARSNET. The final selection of a single mission for M2 took place in April 1993. STEP was not selected for M2 but made a very close second. The program is continuing in modified form.

  3. Equivalent dynamic model of DEMES rotary joint

    NASA Astrophysics Data System (ADS)

    Zhao, Jianwen; Wang, Shu; Xing, Zhiguang; McCoul, David; Niu, Junyang; Huang, Bo; Liu, Liwu; Leng, Jinsong

    2016-07-01

    The dielectric elastomer minimum energy structure (DEMES) can realize large angular deformations by a small voltage-induced strain of the dielectric elastomer (DE), so it is a suitable candidate to make a rotary joint for a soft robot. Dynamic analysis is necessary for some applications, but the dynamic response of DEMESs is difficult to model because of the complicated morphology and viscoelasticity of the DE film. In this paper, a method composed of theoretical analysis and experimental measurement is presented to model the dynamic response of a DEMES rotary joint under an alternating voltage. Based on measurements of equivalent driving force and damping of the DEMES, the model can be derived. Some experiments were carried out to validate the equivalent dynamic model. The maximum angle error between model and experiment is greater than ten degrees, but it is acceptable to predict angular velocity of the DEMES, therefore, it can be applied in feedforward–feedback compound control.

  4. Gingiva Equivalents Secrete Negligible Amounts of Key Chemokines Involved in Langerhans Cell Migration Compared to Skin Equivalents

    PubMed Central

    Kosten, Ilona J.; Buskermolen, Jeroen K.; Spiekstra, Sander W.; de Gruijl, Tanja D.; Gibbs, Susan

    2015-01-01

    Both oral mucosa and skin have the capacity to maintain immune homeostasis or regulate immune responses upon environmental assault. Whereas much is known about key innate immune events in skin, little is known about oral mucosa. Comparative studies are limited due to the scarce supply of oral mucosa for ex vivo studies. Therefore, we used organotypic tissue equivalents (reconstructed epithelium on fibroblast-populated collagen hydrogel) to study cross talk between cells. Oral mucosa and skin equivalents were compared regarding secretion of cytokines and chemokines involved in LC migration and general inflammation. Basal secretion, representative of homeostasis, and also secretion after stimulation with TNFα, an allergen (cinnamaldehyde), or an irritant (SDS) were assessed. We found that proinflammatory IL-18 and chemokines CCL2, CCL20, and CXCL12, all involved in LC migration, were predominantly secreted by skin as compared to gingiva. Furthermore, CCL27 was predominantly secreted by skin whereas CCL28 was predominantly secreted by gingiva. In contrast, general inflammatory cytokines IL-6 and CXCL8 were secreted similarly by skin and gingiva. These results indicate that the cytokines and chemokines triggering innate immunity and LC migration are different in skin and gingiva. This differential regulation should be figured into novel therapy or vaccination strategies in the context of skin versus mucosa. PMID:26539556

  5. Equivalent impedance of a rough interface

    NASA Astrophysics Data System (ADS)

    Zhuk, N. P.; Tret'iakov, O. A.

    1987-10-01

    An equivalent-impedance (EI) dyad is constructed for a rough and plane (on the average) interface dividing two plane-stratified magnetodielectric media. Its characteristics are related to those of a smooth surface and to the scattering properties of the roughnesses. It is shown that the Hermitian part of an EI dyad is formed through field scattering by roughnesses into the propagating natural modes of the regular medium.

  6. Equivalent Circuit Modeling of Hysteresis Motors

    SciTech Connect

    Nitao, J J; Scharlemann, E T; Kirkendall, B A

    2009-08-31

    We performed a literature review and found that many equivalent circuit models of hysteresis motors in use today are incorrect. The model by Miyairi and Kataoka (1965) is the correct one. We extended the model by transforming it to quadrature coordinates, amenable to circuit or digital simulation. 'Hunting' is an oscillatory phenomenon often observed in hysteresis motors. While several works have attempted to model the phenomenon with some partial success, we present a new complete model that predicts hunting from first principles.

  7. Capacitors with low equivalent series resistance

    NASA Technical Reports Server (NTRS)

    Fleig, Patrick Franz (Inventor); Lakeman, Charles D. E. (Inventor); Fuge, Mark (Inventor)

    2011-01-01

    An electric double layer capacitor (EDLC) in a coin or button cell configuration having low equivalent series resistance (ESR). The capacitor comprises mesh or other porous metal that is attached via conducting adhesive to one or both the current collectors. The mesh is embedded into the surface of the adjacent electrode, thereby reducing the interfacial resistance between the electrode and the current collector, thus reducing the ESR of the capacitor.

  8. Global equivalent magnetization of the oceanic lithosphere

    NASA Astrophysics Data System (ADS)

    Dyment, J.; Choi, Y.; Hamoudi, M.; Lesur, V.; Thebault, E.

    2015-11-01

    As a by-product of the construction of a new World Digital Magnetic Anomaly Map over oceanic areas, we use an original approach based on the global forward modeling of seafloor spreading magnetic anomalies and their comparison to the available marine magnetic data to derive the first map of the equivalent magnetization over the World's ocean. This map reveals consistent patterns related to the age of the oceanic lithosphere, the spreading rate at which it was formed, and the presence of mantle thermal anomalies which affects seafloor spreading and the resulting lithosphere. As for the age, the equivalent magnetization decreases significantly during the first 10-15 Myr after its formation, probably due to the alteration of crustal magnetic minerals under pervasive hydrothermal alteration, then increases regularly between 20 and 70 Ma, reflecting variations in the field strength or source effects such as the acquisition of a secondary magnetization. As for the spreading rate, the equivalent magnetization is twice as strong in areas formed at fast rate than in those formed at slow rate, with a threshold at ∼40 km/Myr, in agreement with an independent global analysis of the amplitude of Anomaly 25. This result, combined with those from the study of the anomalous skewness of marine magnetic anomalies, allows building a unified model for the magnetic structure of normal oceanic lithosphere as a function of spreading rate. Finally, specific areas affected by thermal mantle anomalies at the time of their formation exhibit peculiar equivalent magnetization signatures, such as the cold Australian-Antarctic Discordance, marked by a lower magnetization, and several hotspots, marked by a high magnetization.

  9. The Otto-engine-equivalent vehicle concept

    NASA Technical Reports Server (NTRS)

    Dowdy, M. W.; Couch, M. D.

    1978-01-01

    A vehicle comparison methodology based on the Otto-Engine Equivalent (OEE) vehicle concept is described. As an illustration of this methodology, the concept is used to make projections of the fuel economy potential of passenger cars using various alternative power systems. Sensitivities of OEE vehicle results to assumptions made in the calculational procedure are discussed. Factors considered include engine torque boundary, rear axle ratio, performance criteria, engine transient response, and transmission shift logic.

  10. Quantum mechanics from an equivalence principle

    SciTech Connect

    Faraggi, A.E.; Matone, M.

    1997-05-15

    The authors show that requiring diffeomorphic equivalence for one-dimensional stationary states implies that the reduced action S{sub 0} satisfies the quantum Hamilton-Jacobi equation with the Planck constant playing the role of a covariantizing parameter. The construction shows the existence of a fundamental initial condition which is strictly related to the Moebius symmetry of the Legendre transform and to its involutive character. The universal nature of the initial condition implies the Schroedinger equation in any dimension.

  11. Dioxin equivalency: Challenge to dose extrapolation

    SciTech Connect

    Brown, J.F. Jr.; Silkworth, J.B.

    1995-12-31

    Extensive research has shown that all biological effects of dioxin-like agents are mediated via a single biochemical target, the Ah receptor (AhR), and that the relative biologic potencies of such agents in any given system, coupled with their exposure levels, may be described in terms of toxic equivalents (TEQ). It has also shown that the TEQ sources include not only chlorinated species such as the dioxins (PCDDs), PCDFs, and coplanar PCBs, but also non-chlorinated substances such as the PAHs of wood smoke, the AhR agonists of cooked meat, and the indolocarbazol (ICZ) derived from cruciferous vegetables. Humans have probably had elevated exposures to these non-chlorinated TEQ sources ever since the discoveries of fire, cooking, and the culinary use of Brassica spp. Recent assays of CYP1A2 induction show that these ``natural`` or ``traditional`` AhR agonists are contributing 50--100 times as much to average human TEQ exposures as do the chlorinated xenobiotics. Currently, the safe doses of the xenobiotic TEQ sources are estimated from their NOAELs and large extrapolation factors, derived from arbitrary mathematical models, whereas the NOAELs themselves are regarded as the safe doses for the TEQs of traditional dietary components. Available scientific data can neither support nor refute either approach to assessing the health risk of an individual chemical substance. However, if two substances be toxicologically equivalent, then their TEQ-adjusted health risks must also be equivalent, and the same dose extrapolation procedure should be used for both.

  12. Semantic relatedness for evaluation of course equivalencies

    NASA Astrophysics Data System (ADS)

    Yang, Beibei

    Semantic relatedness, or its inverse, semantic distance, measures the degree of closeness between two pieces of text determined by their meaning. Related work typically measures semantics based on a sparse knowledge base such as WordNet or Cyc that requires intensive manual efforts to build and maintain. Other work is based on a corpus such as the Brown corpus, or more recently, Wikipedia. This dissertation proposes two approaches to applying semantic relatedness to the problem of suggesting transfer course equivalencies. Two course descriptions are given as input to feed the proposed algorithms, which output a value that can be used to help determine if the courses are equivalent. The first proposed approach uses traditional knowledge sources such as WordNet and corpora for courses from multiple fields of study. The second approach uses Wikipedia, the openly-editable encyclopedia, and it focuses on courses from a technical field such as Computer Science. This work shows that it is promising to adapt semantic relatedness to the education field for matching equivalencies between transfer courses. A semantic relatedness measure using traditional knowledge sources such as WordNet performs relatively well on non-technical courses. However, due to the "knowledge acquisition bottleneck," such a resource is not ideal for technical courses, which use an extensive and growing set of technical terms. To address the problem, this work proposes a Wikipedia-based approach which is later shown to be more correlated to human judgment compared to previous work.

  13. TNT equivalency of M10 propellant

    NASA Technical Reports Server (NTRS)

    Mcintyre, F. L.; Price, P.

    1978-01-01

    Peak, side-on blast overpressure and scaled, positive impulse have been measured for M10 single-perforated propellant, web size 0.018 inches, using configurations that simulate the handling of bulk material during processing and shipment. Quantities of 11.34, 22.7, 45.4, and 65.8 kg were tested in orthorhombic shipping containers and fiberboard boxes. High explosive equivalency values for each test series were obtained as a function of scaled distance by comparison to known pressure, arrival time and impulse characteristics for hemispherical TNT surface bursts. The equivalencies were found to depend significantly on scaled distance, with higher values of 150-100 percent (pressure) and 350-125 percent (positive impulse) for the extremes within the range from 1.19 to 3.57 m/cube root of kg. Equivalencies as low as 60-140 percent (pressure) and 30-75 percent (positive impulse) were obtained in the range of 7.14 to 15.8 m/cube root of kg. Within experimental error, both peak pressure and positive impulse scaled as a function of charge weight for all quantities tested in the orthorhombic configuration.

  14. Probing Quantum Violations of the Equivalence Principle

    NASA Astrophysics Data System (ADS)

    Adunas, G. Z.; Rodriguez-Milla, E.; Ahluwalia, D. V.

    2001-02-01

    The joint realm of quantum mechanics and general-relativistic description of gravitation is becoming increasingly accessible to terrestrial experiments and observations. In this essay we study the emerging indications of the violation of equivalence principle (VEP). While the solar neutrino anomaly may find its natural explanation in a VEP, the statistically significant discrepancy observed in the gravitationally induced phases of neutron interferometry seems to be the first indication of a VEP. However, such a view would seem immediately challenged by the atomic interferometry results. The latter experiments see no indications of VEP, in apparent contradiction to the neutron interferometry results. Here we show that these, and related torsion pendulum experiments, probe different aspects of gravity; and that current experimental techniques, when coupled to the solar-neutrino data, may be able to explore quantum mechanically induced violations of the equivalence principle. We predict quantum violation of the equivalence principle (qVEP) for next generation of atomic interferometry experiments. The prediction entails comparing free fall of two different linear superpositions of Cesium atomic states.

  15. The water equivalence of solid phantoms for low energy photon beams

    SciTech Connect

    Hill, Robin; Kuncic, Zdenka; Baldock, Clive

    2010-08-15

    Purpose: To compare and evaluate the dosimetric water equivalence of several commonly used solid phantoms for low energy photon beams. Methods: A total of ten different solid phantom materials was used in the study. The PENELOPE Monte Carlo code was used to calculate depth doses and beam profiles in all the phantom materials as well as the dose to a small water voxel at the surface of the solid phantom. These doses were compared to the corresponding doses calculated in a water phantom. The primary photon beams used ranged in energy from 50 to 280 kVp. Results: A number of phantom materials had excellent agreement in dose compared to water for all the x-ray beam energies studied. RMI457 Solid Water, Virtual Water, PAGAT, A150, and Plastic Water DT all had depth doses that agreed with those in water to within 2%. For these same phantom materials, the dose changes in the water voxel at the surface of the solid phantom were within 2%, except for A150, which agreed to within 2.7%. By comparison, the largest differences in depth doses occurred for Plastic Water (-21.7%) and polystyrene (17.6%) for the 50 kVp energy photon beam and 8 cm diameter field size. Plastic Water gave the largest difference in the normalized beam profiles with differences of up to 3.5% as compared to water. Surface dose changes, due to the presence of the solid phantom acting as the backscatter material, were found to be up to 9.1% for polystyrene with significant differences also found for Plastic Water, PMMA, and RW3 phantoms. Conclusions: The following solid phantoms can be considered water equivalent and are recommended for relative dosimetry of low energy photon beams: A150, PAGAT, Plastic Water DT, RMI457 Solid Water, and Virtual Water. However, the following solid phantoms give significant differences, compared to water, in depth doses, profiles, and/or in surface doses due to backscatter changes: Plastic Water, PMMA, polystyrene, PRESAGE, and RW3.

  16. Tissue repair

    PubMed Central

    2010-01-01

    As living beings that encounter every kind of traumatic event from paper cut to myocardial infarction, we must possess ways to heal damaged tissues. While some animals are able to regrow complete body parts following injury (such as the earthworm who grows a new head following bisection), humans are sadly incapable of such feats. Our means of recovery following tissue damage consists largely of repair rather than pure regeneration. Thousands of times in our lives, a meticulously scripted but unseen wound healing drama plays, with cells serving as actors, extracellular matrix as the setting and growth factors as the means of communication. This article briefly reviews the cells involved in tissue repair, their signaling and proliferation mechanisms and the function of the extracellular matrix, then presents the actors and script for the three acts of the tissue repair drama. PMID:21220961

  17. Implementation of an analytical model for leakage neutron equivalent dose in a proton radiotherapy planning system.

    PubMed

    Eley, John; Newhauser, Wayne; Homann, Kenneth; Howell, Rebecca; Schneider, Christopher; Durante, Marco; Bert, Christoph

    2015-01-01

    Equivalent dose from neutrons produced during proton radiotherapy increases the predicted risk of radiogenic late effects. However, out-of-field neutron dose is not taken into account by commercial proton radiotherapy treatment planning systems. The purpose of this study was to demonstrate the feasibility of implementing an analytical model to calculate leakage neutron equivalent dose in a treatment planning system. Passive scattering proton treatment plans were created for a water phantom and for a patient. For both the phantom and patient, the neutron equivalent doses were small but non-negligible and extended far beyond the therapeutic field. The time required for neutron equivalent dose calculation was 1.6 times longer than that required for proton dose calculation, with a total calculation time of less than 1 h on one processor for both treatment plans. Our results demonstrate that it is feasible to predict neutron equivalent dose distributions using an analytical dose algorithm for individual patients with irregular surfaces and internal tissue heterogeneities. Eventually, personalized estimates of neutron equivalent dose to organs far from the treatment field may guide clinicians to create treatment plans that reduce the risk of late effects. PMID:25768061

  18. Implementation of an Analytical Model for Leakage Neutron Equivalent Dose in a Proton Radiotherapy Planning System

    PubMed Central

    Eley, John; Newhauser, Wayne; Homann, Kenneth; Howell, Rebecca; Schneider, Christopher; Durante, Marco; Bert, Christoph

    2015-01-01

    Equivalent dose from neutrons produced during proton radiotherapy increases the predicted risk of radiogenic late effects. However, out-of-field neutron dose is not taken into account by commercial proton radiotherapy treatment planning systems. The purpose of this study was to demonstrate the feasibility of implementing an analytical model to calculate leakage neutron equivalent dose in a treatment planning system. Passive scattering proton treatment plans were created for a water phantom and for a patient. For both the phantom and patient, the neutron equivalent doses were small but non-negligible and extended far beyond the therapeutic field. The time required for neutron equivalent dose calculation was 1.6 times longer than that required for proton dose calculation, with a total calculation time of less than 1 h on one processor for both treatment plans. Our results demonstrate that it is feasible to predict neutron equivalent dose distributions using an analytical dose algorithm for individual patients with irregular surfaces and internal tissue heterogeneities. Eventually, personalized estimates of neutron equivalent dose to organs far from the treatment field may guide clinicians to create treatment plans that reduce the risk of late effects. PMID:25768061

  19. Method for the prediction of the effective dose equivalent to the crew of the International Space Station

    NASA Astrophysics Data System (ADS)

    El-Jaby, Samy; Tomi, Leena; Sihver, Lembit; Sato, Tatsuhiko; Richardson, Richard B.; Lewis, Brent J.

    2014-03-01

    This paper describes a methodology for assessing the pre-mission exposure of space crew aboard the International Space Station (ISS) in terms of an effective dose equivalent. In this approach, the PHITS Monte Carlo code was used to assess the particle transport of galactic cosmic radiation (GCR) and trapped radiation for solar maximum and minimum conditions through an aluminum shield thickness. From these predicted spectra, and using fluence-to-dose conversion factors, a scaling ratio of the effective dose equivalent rate to the ICRU ambient dose equivalent rate at a 10 mm depth was determined. Only contributions from secondary neutrons, protons, and alpha particles were considered in this analysis. Measurements made with a tissue equivalent proportional counter (TEPC) located at Service Module panel 327, as captured through a semi-empirical correlation in the ISSCREM code, where then scaled using this conversion factor for prediction of the effective dose equivalent. This analysis shows that at this location within the service module, the total effective dose equivalent is 10-30% less than the total TEPC dose equivalent. Approximately 75-85% of the effective dose equivalent is derived from the GCR. This methodology provides an opportunity for pre-flight predictions of the effective dose equivalent and therefore offers a means to assess the health risks of radiation exposure on ISS flight crew.

  20. Equivalence of pure propane and propane TE gases for microdosimetric measurements.

    PubMed

    Chiriotti, S; Moro, D; Colautti, P; Conte, V; Grosswendt, B

    2015-09-01

    A tissue-equivalent proportional counter (TEPC) simulates micrometric volumes of tissue if the energy deposited in the counter cavity is the same as that in the tissue volume. Nevertheless, a TEPC measures only the ionisations created in the gas, which are later converted into imparted energy. Therefore, the equivalence of the simulated diameter (Dρ) in two gases should be based on the equality of the mean number of ions pairs in the gas rather than on the imparted energy. Propane-based tissue-equivalent gas is the most commonly used gas mixture at present, but it has the drawback that its composition may change with time. From this point of view, the use of pure propane offers practical advantages: higher gas gain and longer stability. In this work, microdosimetric measurements performed with pure propane, at site sizes 0.05 mg cm(-2) ≤ Dρ ≤ 0.3 mg cm(-2), demonstrate that the response of a propane-filled detector in gamma and in neutron fields is almost the same if an appropriate gas density is used. PMID:25944956

  1. Determination of equivalent breast phantoms for different age groups of Taiwanese women: An experimental approach

    SciTech Connect

    Dong, Shang-Lung; Chu, Tieh-Chi; Lin, Yung-Chien; Lan, Gong-Yau; Yeh, Yu-Hsiu; Chen, Sharon; Chuang, Keh-Shih

    2011-07-15

    Purpose: Polymethylmethacrylate (PMMA) slab is one of the mostly used phantoms for studying breast dosimetry in mammography. The purpose of this study was to evaluate the equivalence between exposure factors acquired from PMMA slabs and patient cases of different age groups of Taiwanese women in mammography. Methods: This study included 3910 craniocaudal screen/film mammograms on Taiwanese women acquired on one mammographic unit. The tube loading, compressed breast thickness (CBT), compression force, tube voltage, and target/filter combination for each mammogram were collected for all patients. The glandularity and the equivalent thickness of PMMA were determined for each breast using the exposure factors of the breast in combination with experimental measurements from breast-tissue-equivalent attenuation slabs. Equivalent thicknesses of PMMA to the breasts of Taiwanese women were then estimated. Results: The average {+-} standard deviation CBT and breast glandularity in this study were 4.2 {+-} 1.0 cm and 54% {+-} 23%, respectively. The average equivalent PMMA thickness was 4.0 {+-} 0.7 cm. PMMA slabs producing equivalent exposure factors as in the breasts of Taiwanese women were determined for the age groups 30-49 yr and 50-69 yr. For the 4-cm PMMA slab, the CBT and glandularity values of the equivalent breast were 4.1 cm and 65%, respectively, for the age group 30-49 yr and 4.4 cm and 44%, respectively, for the age group 50-69 yr. Conclusions: The average thickness of PMMA slabs producing the same exposure factors as observed in a large group of Taiwanese women is less than that reported for American women. The results from this study can provide useful information for determining a suitable thickness of PMMA for mammographic dose survey in Taiwan. The equivalence of PMMA slabs and the breasts of Taiwanese women is provided to allow average glandular dose assessment in clinical practice.

  2. Toxic equivalence factors, problems and limitations.

    PubMed

    Neumann, H G

    1996-01-01

    It is a particular problem to set tolerance levels for mixtures containing chemicals classified as carcinogens. In the case of chlorinated dioxin and furan congeners, 'toxicity equivalence factors' (TEFs) were introduced. This concept has problems in itself and cannot be readily transferred to other mixtures, such as those of monocyclic nitroarenes in wastes of trinitrotoluene (TNT)-based explosives. The difficulties in finding suitable endpoints to compare the components are discussed (methaemoglobin formation; quantitative structure-activity relationships; mutagenicity; carcinogenicity). An alternative approach for the development tolerance levels in this instance is based on results obtained by measuring haemoglobin adducts as biomarkers of the most prevalent mixture components in humans. PMID:9119314

  3. The equivalence principle in a quantum world

    NASA Astrophysics Data System (ADS)

    Bjerrum-Bohr, N. E. J.; Donoghue, John F.; El-Menoufi, Basem Kamal; Holstein, Barry R.; Planté, Ludovic; Vanhove, Pierre

    2015-09-01

    We show how modern methods can be applied to quantum gravity at low energy. We test how quantum corrections challenge the classical framework behind the equivalence principle (EP), for instance through introduction of nonlocality from quantum physics, embodied in the uncertainty principle. When the energy is small, we now have the tools to address this conflict explicitly. Despite the violation of some classical concepts, the EP continues to provide the core of the quantum gravity framework through the symmetry — general coordinate invariance — that is used to organize the effective field theory (EFT).

  4. Dark matter and the equivalence principle

    NASA Technical Reports Server (NTRS)

    Frieman, Joshua A.; Gradwohl, Ben-Ami

    1991-01-01

    If the dark matter in galaxies and clusters is nonbaryonic, it can interact with additional long-range fields that are invisible to experimental tests of the equivalence principle. The astrophysical and cosmological implications of a long-range force coupled only to the dark matter are discussed and rather tight constraints on its strength are found. If the force is repulsive (attractive), the masses of galaxy groups and clusters (and the mean density of the universe inferred from them) have been systematically underestimated (overestimated). Such an interaction also has unusual implications for the growth of large-scale structure.

  5. Mechanical equivalent of quantum heat engines.

    PubMed

    Arnaud, Jacques; Chusseau, Laurent; Philippe, Fabrice

    2008-06-01

    Quantum heat engines employ as working agents multilevel systems instead of classical gases. We show that under some conditions quantum heat engines are equivalent to a series of reservoirs at different altitudes containing balls of various weights. A cycle consists of picking up at random a ball from one reservoir and carrying it to the next, thereby performing or absorbing some work. In particular, quantum heat engines, employing two-level atoms as working agents, are modeled by reservoirs containing balls of weight 0 or 1. The mechanical model helps us prove that the maximum efficiency of quantum heat engines is the Carnot efficiency. Heat pumps and negative temperatures are considered. PMID:18643212

  6. Validation Of Equivalent Viscous Damping Methodologies

    NASA Astrophysics Data System (ADS)

    Vaquer Araujo, Xavier; Fransen, S. H. J. A.; Germes, S.; Thiry, N.

    2012-07-01

    An important step in the design and verification process of spacecraft structures is the coupled dynamic analysis with the launch vehicle in the low-frequency domain. To obtain accurate predictions of the satellite’s dynamic environment it is essential that the damping of the system is correctly defined and taken into account within the resolution methodologies for the Coupled Loads Analysis (CLA). When working with finite element models, the materials’ damping is characterized by structural damping ratios. In addition, most of the load cases present in the CLA are transient excitations so the resolution of the equations of motion must be done in the time domain. Unfortunately, transient analyses cannot be carried out using structural damping models. Thus, a transformation from a structural to a viscous damping characterization is necessary. Nevertheless, this transformation is not trivial. There exist many methodologies aiming at computing an equivalent viscous damping matrix of the system so it can be used in transient analyses. This paper describes the results obtained in the validation of equivalent viscous damping methodologies used in the European Space Agency. This work permitted to identify the limitations of these methodologies and to come up with an enhanced methodology that predicts more reliable results.

  7. Equivalent Relaxations of Optimal Power Flow

    SciTech Connect

    Bose, S; Low, SH; Teeraratkul, T; Hassibi, B

    2015-03-01

    Several convex relaxations of the optimal power flow (OPF) problem have recently been developed using both bus injection models and branch flow models. In this paper, we prove relations among three convex relaxations: a semidefinite relaxation that computes a full matrix, a chordal relaxation based on a chordal extension of the network graph, and a second-order cone relaxation that computes the smallest partial matrix. We prove a bijection between the feasible sets of the OPF in the bus injection model and the branch flow model, establishing the equivalence of these two models and their second-order cone relaxations. Our results imply that, for radial networks, all these relaxations are equivalent and one should always solve the second-order cone relaxation. For mesh networks, the semidefinite relaxation and the chordal relaxation are equally tight and both are strictly tighter than the second-order cone relaxation. Therefore, for mesh networks, one should either solve the chordal relaxation or the SOCP relaxation, trading off tightness and the required computational effort. Simulations are used to illustrate these results.

  8. Equivalence of topological insulators and superconductors

    NASA Astrophysics Data System (ADS)

    Cobanera, Emilio; Ortiz, Gerardo

    2015-10-01

    Systems of free fermions are classified by symmetry, space dimensionality, and topological properties described by K homology. Those systems belonging to different classes are inequivalent. In contrast, we show that by taking a many-body/Fock-space viewpoint it becomes possible to establish equivalences of topological insulators and superconductors in terms of duality transformations. These mappings connect topologically inequivalent systems of fermions, jumping across entries in existent classification tables, because of the phenomenon of symmetry transmutation by which a symmetry and its dual partner have identical algebraic properties but very different physical interpretations. To constrain our study to established classification tables, we define and characterize mathematically Gaussian dualities as dualities mapping free fermions to free fermions (and interacting to interacting). By introducing a large, flexible class of Gaussian dualities we show that any insulator is dual to a superconductor, and that fermionic edge modes are dual to Majorana edge modes, that is, the Gaussian dualities of this paper preserve the bulk-boundary correspondence. Transmutation of relevant symmetries, particle number, translation, and time reversal is also investigated in detail. As illustrative examples, we show the duality equivalence of the dimerized Peierls chain and the Majorana chain of Kitaev, and a two-dimensional Kekulé-type topological insulator, including graphene as a special instance in coupling space, dual to a p -wave superconductor. Since our analysis extends to interacting fermion systems, we also briefly discuss some such applications.

  9. Equivalence of trans paths in ion channels

    NASA Astrophysics Data System (ADS)

    Alvarez, Juan; Hajek, Bruce

    2006-04-01

    We explore stochastic models for the study of ion transport in biological cells. Analysis of these models explains and explores an interesting feature of ion transport observed by biophysicists. Namely, the average time it takes ions to cross certain ion channels is the same in either direction, even if there is an electric potential difference across the channels. It is shown for simple single ion models that the distribution of a path (i.e., the history of location versus time) of an ion crossing the channel in one direction has the same distribution as the time-reversed path of an ion crossing the channel in the reverse direction. Therefore, not only is the mean duration of these paths equal, but other measures, such as the variance of passage time or the mean time a path spends within a specified section of the channel, are also the same for both directions of traversal. The feature is also explored for channels with interacting ions. If a system of interacting ions is in reversible equilibrium (net flux is zero), then the equivalence of the left-to-right trans paths with the time-reversed right-to-left trans paths still holds. However, if the system is in equilibrium, but not reversible equilibrium, then such equivalence need not hold.

  10. Planck Constant Determination from Power Equivalence

    NASA Astrophysics Data System (ADS)

    Newell, David B.

    2000-04-01

    Equating mechanical to electrical power links the kilogram, the meter, and the second to the practical realizations of the ohm and the volt derived from the quantum Hall and the Josephson effects, yielding an SI determination of the Planck constant. The NIST watt balance uses this power equivalence principle, and in 1998 measured the Planck constant with a combined relative standard uncertainty of 8.7 x 10-8, the most accurate determination to date. The next generation of the NIST watt balance is now being assembled. Modification to the experimental facilities have been made to reduce the uncertainty components from vibrations and electromagnetic interference. A vacuum chamber has been installed to reduce the uncertainty components associated with performing the experiment in air. Most of the apparatus is in place and diagnostic testing of the balance should begin this year. Once a combined relative standard uncertainty of one part in 10-8 has been reached, the power equivalence principle can be used to monitor the possible drift in the artifact mass standard, the kilogram, and provide an accurate alternative definition of mass in terms of fundamental constants. *Electricity Division, Electronics and Electrical Engineering Laboratory, Technology Administration, U.S. Department of Commerce. Contribution of the National Institute of Standards and Technology, not subject to copyright in the U.S.

  11. Investigating Starburst Galaxy Emission Line Equivalent Widths

    NASA Astrophysics Data System (ADS)

    Meskhidze, Helen; Richardson, Chris T.

    2016-01-01

    Modeling star forming galaxies with spectral synthesis codes allows us to study the gas conditions and excitation mechanisms that are necessary to reproduce high ionization emission lines in both local and high-z galaxies. Our study uses the locally optimally-emitting clouds model to develop an atlas of starburst galaxy emission line equivalent widths. Specifically, we address the following question: What physical conditions are necessary to produce strong high ionization emission lines assuming photoionization via starlight? Here we present the results of our photoionization simulations: an atlas spanning 15 orders of magnitude in ionizing flux and 10 orders of magnitude in hydrogen density that tracks over 150 emission lines ranging from the UV to the near IR. Each simulation grid contains ~1.5x104 photoionization models calculated by supplying a spectral energy distribution, grain content, and chemical abundances. Specifically, we will be discussing the effects on the emission line equivalent widths of varying the metallicity of the cloud, Z = 0.2 Z⊙ to Z = 5.0 Z⊙, and varying the star-formation history, using the instantaneous and continuous evolution tracks and the newly released Starburst99 Geneva rotation tracks.

  12. Breaking of Ensemble Equivalence in Networks

    NASA Astrophysics Data System (ADS)

    Squartini, Tiziano; de Mol, Joey; den Hollander, Frank; Garlaschelli, Diego

    2015-12-01

    It is generally believed that, in the thermodynamic limit, the microcanonical description as a function of energy coincides with the canonical description as a function of temperature. However, various examples of systems for which the microcanonical and canonical ensembles are not equivalent have been identified. A complete theory of this intriguing phenomenon is still missing. Here we show that ensemble nonequivalence can manifest itself also in random graphs with topological constraints. We find that, while graphs with a given number of links are ensemble equivalent, graphs with a given degree sequence are not. This result holds irrespective of whether the energy is nonadditive (as in unipartite graphs) or additive (as in bipartite graphs). In contrast with previous expectations, our results show that (1) physically, nonequivalence can be induced by an extensive number of local constraints, and not necessarily by long-range interactions or nonadditivity, (2) mathematically, nonequivalence is determined by a different large-deviation behavior of microcanonical and canonical probabilities for a single microstate, and not necessarily for almost all microstates. The latter criterion, which is entirely local, is not restricted to networks and holds in general.

  13. Enhancement of Cortical Network Activity in vitro and Promotion of GABAergic Neurogenesis by Stimulation with an Electromagnetic Field with a 150 MHz Carrier Wave Pulsed with an Alternating 10 and 16 Hz Modulation.

    PubMed

    Gramowski-Voß, Alexandra; Schwertle, Hans-Joachim; Pielka, Anna-Maria; Schultz, Luise; Steder, Anne; Jügelt, Konstantin; Axmann, Jürgen; Pries, Wolfgang

    2015-01-01

    In recent years, various stimuli were identified capable of enhancing neurogenesis, a process which is dysfunctional in the senescent brain and in neurodegenerative and certain neuropsychiatric diseases. Applications of electromagnetic fields to brain tissue have been shown to affect cellular properties and their importance for therapies in medicine is recognized. In this study, differentiating murine cortical networks on multiwell microelectrode arrays were repeatedly exposed to an extremely low-electromagnetic field (ELEMF) with alternating 10 and 16 Hz frequencies piggy backed onto a 150 MHz carrier frequency. The ELEMF exposure stimulated the electrical network activity and intensified the structure of bursts. Further, the exposure to electromagnetic fields within the first 28 days in vitro of the differentiation of the network activity induced also reorganization within the burst structure. This effect was already most pronounced at 14 days in vitro after 10 days of exposure. Overall, the development of cortical activity under these conditions was accelerated. These functional electrophysiological changes were accompanied by morphological ones. The percentage of neurons in the neuron glia co-culture was increased without affecting the total number of cells, indicating an enhancement of neurogenesis. The ELEMF exposure selectively promoted the proliferation of a particular population of neurons, evidenced by the increased proportion of GABAergic neurons. The results support the initial hypothesis that this kind of ELEMF stimulation could be a treatment option for specific indications with promising potential for CNS applications, especially for degenerative diseases, such as Alzheimer's disease and other dementias. PMID:26236278

  14. Equivalent magnetization over the World's Ocean

    NASA Astrophysics Data System (ADS)

    Dyment, J.; Choi, Y.; Hamoudi, M.; Erwan, T.; Lesur, V.

    2014-12-01

    As a by-product of our recent work to build a candidate model over the oceans for the World Digital Magnetic Anomaly Map (WDMAM) version 2, we derived global distributions of the equivalent magnetization in oceanic domains. In a first step, we use classic point source forward modeling on a spherical Earth to build a forward model of the marine magnetic anomalies at sea-surface. We estimate magnetization vectors using the age map of the ocean floor, the relative plate motions, the apparent polar wander path for Africa, and a geomagnetic reversal time scale. As magnetized source geometry, we assume 1 km-thick layer bearing a 10 A/m magnetization following the topography of the oceanic basement as defined by the bathymetry and sedimentary thickness. Adding a present-day geomagnetic field model allows the computation of our initial magnetic anomaly model. In a second step, we adjust this model to the existing marine magnetic anomaly data, in order to make it consistent with these data. To do so, we extract synthetic magnetic along the ship tracks for which real data are available and we compare quantitatively the measured and computed anomalies on 100, 200 or 400 km-long sliding windows (depending the spreading rate). Among the possible comparison criteria, we discard the maximal range - too dependent on local values - and the correlation and coherency - the geographical adjustment between model and data being not accurate enough - to favor the standard deviation around the mean value. The ratio between the standard deviations of data and model on each sliding window represent an estimate of the magnetization ratio causing the anomalies, which we interpolate to adjust the initial magnetic anomaly model to the data and therefore compute a final model to be included in our WDMAM candidate over the oceanic regions lacking data. The above ratio, after division by the magnetization of 10 A/m used in the model, represents an estimate of the equivalent magnetization under the

  15. Calculation of dose, dose equivalent, and relative biological effectiveness for high charge and energy ion beams

    NASA Technical Reports Server (NTRS)

    Wilson, J. W.; Chun, S. Y.; Reginatto, M.; Hajnal, F.

    1995-01-01

    The Green's function for the transport of ions of high charge and energy is utilized with a nuclear fragmentation database to evaluate dose, dose equivalent, and RBE for C3H10T1/2 cell survival and neo-plastic transformation as function of depth in soft tissue. Such evaluations are useful to estimates of biological risk for high altitude aircraft, space operations, accelerator operations, and biomedical application.

  16. Expressivism, Relativism, and the Analytic Equivalence Test.

    PubMed

    Frápolli, Maria J; Villanueva, Neftalí

    2015-01-01

    The purpose of this paper is to show that, pace (Field, 2009), MacFarlane's assessment relativism and expressivism should be sharply distinguished. We do so by arguing that relativism and expressivism exemplify two very different approaches to context-dependence. Relativism, on the one hand, shares with other contemporary approaches a bottom-up, building block, model, while expressivism is part of a different tradition, one that might include Lewis' epistemic contextualism and Frege's content individuation, with which it shares an organic model to deal with context-dependence. The building-block model and the organic model, and thus relativism and expressivism, are set apart with the aid of a particular test: only the building-block model is compatible with the idea that there might be analytically equivalent, and yet different, propositions. PMID:26635690

  17. Torsion Balance Test of Einstein's Equivalence Principle

    NASA Astrophysics Data System (ADS)

    Abercrombie, Michael; Archibald, Adam; Nussinov, Tsitsi; Wagoner, Kasey; Cowsik, Ramanath

    2016-03-01

    We have developed a torsion balance experiment to test the equivalence principle (EP) which follows the solar attractor approach pioneered by Dicke in the early 1960s. By monitoring the response of a balance arranged as a composition dipole with an azimuthally symmetric mass distribution to the gravitational field produced by the Sun, we search for a diurnal modulation of the balance which would indicate a violation of the EP. Since reporting on the status of this experiment last year, the instrument has begun collecting data at a remote underground site. This talk will cover the design and fundamental sensitivity of the balance, and present the results of preliminary analysis of over 1200 hours of data.

  18. Equivalent Hamiltonian for the Lee model

    SciTech Connect

    Jones, H. F.

    2008-03-15

    Using the techniques of quasi-Hermitian quantum mechanics and quantum field theory we use a similarity transformation to construct an equivalent Hermitian Hamiltonian for the Lee model. In the field theory confined to the V/N{theta} sector it effectively decouples V, replacing the three-point interaction of the original Lee model by an additional mass term for the V particle and a four-point interaction between N and {theta}. While the construction is originally motivated by the regime where the bare coupling becomes imaginary, leading to a ghost, it applies equally to the standard Hermitian regime where the bare coupling is real. In that case the similarity transformation becomes a unitary transformation.

  19. Phenomenological approaches of inflation and their equivalence

    NASA Astrophysics Data System (ADS)

    Boubekeur, Lotfi; Giusarma, Elena; Mena, Olga; Ramírez, Héctor

    2015-04-01

    In this work, we analyze two possible alternative and model-independent approaches to describe the inflationary period. The first one assumes a general equation of state during inflation due to Mukhanov, while the second one is based on the slow-roll hierarchy suggested by Hoffman and Turner. We find that, remarkably, the two approaches are equivalent from the observational viewpoint, as they single out the same areas in the parameter space, and agree with the inflationary attractors where successful inflation occurs. Rephrased in terms of the familiar picture of a slowly rolling, canonically normalized scalar field, the resulting inflaton excursions in these two approaches are almost identical. Furthermore, once the Galactic dust polarization data from Planck are included in the numerical fits, inflaton excursions can safely take sub-Planckian values.

  20. Equivalent damage validation by variable cluster analysis

    NASA Astrophysics Data System (ADS)

    Drago, Carlo; Ferlito, Rachele; Zucconi, Maria

    2016-06-01

    The main aim of this work is to perform a clustering analysis on the damage relieved in the old center of L'Aquila after the earthquake occurred on April 6, 2009 and to validate an Indicator of Equivalent Damage ED that summarizes the information reported on the AeDES card regarding the level of damage and their extension on the surface of the buildings. In particular we used a sample of 13442 masonry buildings located in an area characterized by a Macroseismic Intensity equal to 8 [1]. The aim is to ensure the coherence between the clusters and its hierarchy identified in the data of damage detected and in the data of the ED elaborated.

  1. Levothyroxine sodium tablets: chemical equivalence and bioequivalence.

    PubMed

    Curry, S H; Gums, J G; Williams, L L; Curry, R W; Wolfson, B B

    1988-01-01

    Two brands of levothyroxine sodium tablets were compared in vivo for bioequivalence in a double-blind, randomized study. The tablets were identical in levothyroxine content. Evaluation was by means of triiodothyronine (uptake), tetraiodothyronine, free thyroxine index, total triiodothyronine by radioimmunoassay, and thyroid-stimulating hormone measurements. No differences in clinical response were found in a study with a high statistical power. It was concluded that the two brands were bioequivalent because of chemical equivalence, use of micronized levothyroxine powder in tablet production with at least one of the brands, and scrupulous attention to quality control during the manufacturing process, all of which contributed to assurance of homogeneity of the products and close adherence (+/- five percent) to the claimed potency. PMID:3046889

  2. Multiband signal reconstruction for random equivalent sampling

    NASA Astrophysics Data System (ADS)

    Zhao, Y. J.; Liu, C. J.

    2014-10-01

    The random equivalent sampling (RES) is a sampling approach that can be applied to capture high speed repetitive signals with a sampling rate that is much lower than the Nyquist rate. However, the uneven random distribution of the time interval between the excitation pulse and the signal degrades the signal reconstruction performance. For sparse multiband signal sampling, the compressed sensing (CS) based signal reconstruction algorithm can tease out the band supports with overwhelming probability and reduce the impact of uneven random distribution in RES. In this paper, the mathematical model of RES behavior is constructed in the frequency domain. Based on the constructed mathematical model, the band supports of signal can be determined. Experimental results demonstrate that, for a signal with unknown sparse multiband, the proposed CS-based signal reconstruction algorithm is feasible, and the CS reconstruction algorithm outperforms the traditional RES signal reconstruction method.

  3. Klein factors and Fermi-Bose equivalence

    NASA Astrophysics Data System (ADS)

    Lee, Taejin

    2016-06-01

    Generalizing the kink operator of the Heisenberg spin 1/2 model, we construct a set of Klein factors explicitly such that (1+1)-dimensional fermion theories with an arbitrary number of species are mapped onto the corresponding boson theories with the same number of species and vice versa. The actions for the resultant theories do not possess a nontrivial Klein factor. With this set of Klein factors, we are also able to map the simple boundary states, such as the Neumann and the Dirichlet boundary states, of the fermion (boson) theory onto those of the boson (fermion) theory. Applications of the Fermi-Bose equivalence with the constructed Klein factors to well-known (1+1)-dimensional theories have been discussed.

  4. Multiband signal reconstruction for random equivalent sampling.

    PubMed

    Zhao, Y J; Liu, C J

    2014-10-01

    The random equivalent sampling (RES) is a sampling approach that can be applied to capture high speed repetitive signals with a sampling rate that is much lower than the Nyquist rate. However, the uneven random distribution of the time interval between the excitation pulse and the signal degrades the signal reconstruction performance. For sparse multiband signal sampling, the compressed sensing (CS) based signal reconstruction algorithm can tease out the band supports with overwhelming probability and reduce the impact of uneven random distribution in RES. In this paper, the mathematical model of RES behavior is constructed in the frequency domain. Based on the constructed mathematical model, the band supports of signal can be determined. Experimental results demonstrate that, for a signal with unknown sparse multiband, the proposed CS-based signal reconstruction algorithm is feasible, and the CS reconstruction algorithm outperforms the traditional RES signal reconstruction method. PMID:25362458

  5. Expressivism, Relativism, and the Analytic Equivalence Test

    PubMed Central

    Frápolli, Maria J.; Villanueva, Neftalí

    2015-01-01

    The purpose of this paper is to show that, pace (Field, 2009), MacFarlane’s assessment relativism and expressivism should be sharply distinguished. We do so by arguing that relativism and expressivism exemplify two very different approaches to context-dependence. Relativism, on the one hand, shares with other contemporary approaches a bottom–up, building block, model, while expressivism is part of a different tradition, one that might include Lewis’ epistemic contextualism and Frege’s content individuation, with which it shares an organic model to deal with context-dependence. The building-block model and the organic model, and thus relativism and expressivism, are set apart with the aid of a particular test: only the building-block model is compatible with the idea that there might be analytically equivalent, and yet different, propositions. PMID:26635690

  6. Equivalence of topological insulators and superconductors

    NASA Astrophysics Data System (ADS)

    Ortiz, Gerardo; Cobanera, Emilio

    Systems of free fermions are classified by symmetry, space dimensionality, and topological properties described by K-homology. We show that by taking a many-body/Fock space viewpoint it becomes possible to establish equivalences of topological insulators and superconductors in terms of duality transformations. These mappings connect topologically inequivalent systems of fermions, jumping across entries in existent classification tables, because of the phenomenon of symmetry transmutation by which a symmetry and its dual partner have identical algebraic properties but very different physical interpretations and electromagnetic response. Since our analysis extends to interacting fermion systems we also briefly discuss some such applications. To illustrate main concepts we will present dual superconducting partners of paradigmatic models, such as the Haldane Chern insulator as well as a quantum spin Hall effect graphene model.

  7. Snow water equivalent determination by microwave radiometry

    NASA Technical Reports Server (NTRS)

    Chang, A. T. C.; Foster, J. L.; Hall, D. K.; Rango, A.; Hartline, B. K.

    1981-01-01

    One of the most important parameters for accurate snowmelt runoff prediction is snow water equivalent (SWE) which is contentionally monitored using observations made at widely scattered points in or around specific watersheds. Remote sensors which provide data with better spatial and temporal coverage can be used to improve the SWE estimates. Microwave radiation, which can penetrate through a snowpack, may be used to infer the SWE. Calculations made from a microscopic scattering model were used to simulate the effect of varying SWE on the microwave brightness temperature. Data obtained from truck mounted, airborne and spaceborne systems from various test sites were studied. The simulated SWE compares favorable with the measured SWE. In addition, whether the underlying soil is frozen or thawed can be discriminated successfully on the basis of the polarization of the microwave radiation.

  8. Cloning and characterization of a 150 kDa microsphere antigen of Theileria parva that is immunologically cross-reactive with the polymorphic immunodominant molecule (PIM).

    PubMed

    Skilton, R A; Bishop, R P; Wells, C W; Spooner, P R; Gobright, E; Nkonge, C; Musoke, A J; Macklin, M; Iams, K P

    1998-10-01

    To identify the genes encoding novel immunodominant antigens of Theileria parva a lambda gt11 library of piroplasm genomic DNA was immunoscreened with bovine recovery serum and a gene encoding a 150 kDa antigen (p150) was identified. The predicted polypeptide contains an N-terminal secretory signal sequence and a proline-rich region of repeated amino acid motifs. The repeat region is polymorphic between stocks of T. parva in both copy number and sequence, and analysis of the repeat region from 10 stocks of T. parva revealed 5 p150 variants. A monoclonal antibody (mAb) against the T. parva polymorphic immunodominant molecule (PIM) cross-reacted with the recombinant p150. The p150 has sequence homology with a PIM peptide sequence containing the anti-PIM mAb epitope. Immunoelectron microscopy demonstrated that the p150 antigen, like PIM, is located in the microspheres of the sporozoites and is exocytosed following sporozoite invasion of the host lymphocyte. By immunoelectron microscopy p150 was subsequently transiently detectable on the sporozoite surface and in the lymphocyte cytosol. Immunoblotting showed that p150 is also expressed by the schizont stage, but at much lower levels compared to the sporozoite. These results suggest a major role for p150 in the early events of host-sporozoite interaction. PMID:9820853

  9. Elementary equivalence of Chevalley groups over local rings

    SciTech Connect

    Bunina, Elena I

    2010-05-11

    It is proved that (elementary) Chevalley groups over local rings with invertible 2 are elementarily equivalent if and only if their types and weight lattices coincide and the initial rings are elementarily equivalent. Bibliography: 25 titles.

  10. Optimizing Equivalence-Based Instruction: Effects of Training Protocols on Equivalence Class Formation

    ERIC Educational Resources Information Center

    Fienup, Daniel M.; Wright, Nicole A.; Fields, Lanny

    2015-01-01

    Two experiments evaluated the effects of the simple-to-complex and simultaneous training protocols on the formation of academically relevant equivalence classes. The simple-to-complex protocol intersperses derived relations probes with training baseline relations. The simultaneous protocol conducts all training trials and test trials in separate…

  11. 77 FR 32632 - Ambient Air Monitoring Reference and Equivalent Methods: Designation of Three New Equivalent Methods

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-06-01

    ...Notice is hereby given that the Environmental Protection Agency (EPA) has designated, in accordance with 40 CFR Part 53, three new equivalent methods: One for measuring concentrations of nitrogen dioxide (NO2) and two for measuring concentrations of lead (Pb) in the ambient...

  12. 78 FR 67360 - Ambient Air Monitoring Reference and Equivalent Methods: Designation of Five New Equivalent Methods

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-11-12

    ... 31, 2011 (76 FR 54326-54341). Two of the new equivalent methods for PM are automated monitoring... meteorological sensor. With or without optional ESTEL analog inputs/outputs, serial link: 1 RS-232/422; USB port... inlet and zero check enabled; sample permeation dryer. Serial link: 2 RS-232; USB port; Ethernet...

  13. High School Equivalency Testing in Washington. Forum: Responding to Changes in High School Equivalency Testing

    ERIC Educational Resources Information Center

    Kerr, Jon

    2015-01-01

    In 2013, as new high school equivalency exams were being developed and implemented across the nation and states were deciding which test was best for their population, Washington state identified the need to adopt the most rigorous test so that preparation to take it would equip students with the skills to be able to move directly from adult…

  14. FROM CONCEPT TO EQUIVALENCY: THE 503 REGULATIONS AND THE PATHOGEN EQUIVALENCY COMMITTEE (PAPER)

    EPA Science Inventory

    Since its creation in 1985, the Pathogen Equivalency Committee (PEC) has been reviewing innovative and alternative sludge disinfection technologies with regards to their abilities to protect human health and the environment. The PEC is charged to make recommendations on whether t...

  15. FROM CONCEPT TO EQUIVALENCY: THE 503 REGULATIONS AND THE PATHOGEN EQUIVALENCY COMMITTEE

    EPA Science Inventory

    Since its creation in 1985, the Pathogen Equivalency Committee (PEC) has been reviewing innovative and alternative sludge disinfection technologies with regards to their abilities to protect human health and the environment. The PEC is charged to make recommendations on whether t...

  16. Determination and analysis of torsion equivalent stress-equivalent strain relation of low carbon alloy

    NASA Astrophysics Data System (ADS)

    Wang, Jing; Jiang, Gongfeng; Yu, Xiutao; Deng, Tianhua; Zhang, Yiliang

    2008-11-01

    Typical pressure vessel materials' torsion equivalent stress-equivalent strain relationships under large deformation condition are researched in this paper. Because the length and the diameter of the specimen may change under uniaxial tension, it's impossible to make effective measurement and analysis for the mechanical properties of the specimen, especially after the necking. The form and cross-section size of cylindrical specimen do not change in torsion test, so that the large strain's constitutive relationship is more accurate than that obtained from an axial tension test. So that cylindrical specimen's torsion test is attempted to obtain the shear stress-shear strain curves of typical pressure vessel materials 16MnR and Q235. Consider that the stress is non-homogeneous in the cross-section of cylindrical specimen, thin wall tube specimen is also used in the torsion test, and the maximum differences between cylindrical specimen's results and thin-wall tube's are 10% and 13% respectively. Tension true stress-true strain curves, torsion equivalent stress-equivalent strain curves are also compared in this paper and the results showed that description of the torsion constitutive relationship is more complete than that of tension. At last, constitutive equations are fitted and the mathematical representations are obtained.

  17. Scar Tissue.

    PubMed

    McLean, Haydn J

    2015-12-01

    Scar tissue is associated with physical wounds and their mending, but it is also descriptive in portraying the emotional scarring that occurs following adversity, resulting in potential psychological morbidity. Provided the adversity is not severe, such challenges to adaptability may provoke Andrew Solomon's process of forging meaning and building identity. Perceiving an emotional constitution as analogous to the immune system provides a metaphor for appreciating the benefits of emotional challenges, which may provoke greater emotional resilience or posttraumatic growth. PMID:26631526

  18. New equivalent-electrical circuit model and a practical measurement method for human body impedance.

    PubMed

    Chinen, Koyu; Kinjo, Ichiko; Zamami, Aki; Irei, Kotoyo; Nagayama, Kanako

    2015-01-01

    Human body impedance analysis is an effective tool to extract electrical information from tissues in the human body. This paper presents a new measurement method of impedance using armpit electrode and a new equivalent circuit model for the human body. The lowest impedance was measured by using an LCR meter and six electrodes including armpit electrodes. The electrical equivalent circuit model for the cell consists of resistance R and capacitance C. The R represents electrical resistance of the liquid of the inside and outside of the cell, and the C represents high frequency conductance of the cell membrane. We propose an equivalent circuit model which consists of five parallel high frequency-passing CR circuits. The proposed equivalent circuit represents alpha distribution in the impedance measured at a lower frequency range due to ion current of the outside of the cell, and beta distribution at a high frequency range due to the cell membrane and the liquid inside cell. The calculated values by using the proposed equivalent circuit model were consistent with the measured values for the human body impedance. PMID:26406074

  19. 12 CFR 28.15 - Capital equivalency deposits.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 12 Banks and Banking 1 2011-01-01 2011-01-01 false Capital equivalency deposits. 28.15 Section 28... ACTIVITIES Federal Branches and Agencies of Foreign Banks § 28.15 Capital equivalency deposits. (a) Capital... provided by the OCC, a foreign bank's capital equivalency deposits (CED) must consist of: (i)...

  20. 7 CFR 987.105 - Whole equivalent of pitted dates.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... Whole equivalent of pitted dates. For the purposes of this part, the whole date equivalent weight of pitted dates shall be determined by dividing the weight of the pitted dates by 0.83. Identification and... 7 Agriculture 8 2013-01-01 2013-01-01 false Whole equivalent of pitted dates. 987.105 Section...

  1. 7 CFR 987.105 - Whole equivalent of pitted dates.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... Whole equivalent of pitted dates. For the purposes of this part, the whole date equivalent weight of pitted dates shall be determined by dividing the weight of the pitted dates by 0.83. Identification and... 7 Agriculture 8 2014-01-01 2014-01-01 false Whole equivalent of pitted dates. 987.105 Section...

  2. 7 CFR 987.105 - Whole equivalent of pitted dates.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... Whole equivalent of pitted dates. For the purposes of this part, the whole date equivalent weight of pitted dates shall be determined by dividing the weight of the pitted dates by 0.83. Identification and... 7 Agriculture 8 2011-01-01 2011-01-01 false Whole equivalent of pitted dates. 987.105 Section...

  3. 7 CFR 987.105 - Whole equivalent of pitted dates.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... Whole equivalent of pitted dates. For the purposes of this part, the whole date equivalent weight of pitted dates shall be determined by dividing the weight of the pitted dates by 0.83. Identification and... 7 Agriculture 8 2010-01-01 2010-01-01 false Whole equivalent of pitted dates. 987.105 Section...

  4. 7 CFR 987.105 - Whole equivalent of pitted dates.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... Whole equivalent of pitted dates. For the purposes of this part, the whole date equivalent weight of pitted dates shall be determined by dividing the weight of the pitted dates by 0.83. Identification and... 7 Agriculture 8 2012-01-01 2012-01-01 false Whole equivalent of pitted dates. 987.105 Section...

  5. 49 CFR 391.33 - Equivalent of road test.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 5 2010-10-01 2010-10-01 false Equivalent of road test. 391.33 Section 391.33... AND LONGER COMBINATION VEHICLE (LCV) DRIVER INSTRUCTORS Tests § 391.33 Equivalent of road test. (a) In place of, and as equivalent to, the road test required by § 391.31, a person who seeks to drive...

  6. 49 CFR 391.33 - Equivalent of road test.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 5 2014-10-01 2014-10-01 false Equivalent of road test. 391.33 Section 391.33... AND LONGER COMBINATION VEHICLE (LCV) DRIVER INSTRUCTORS Tests § 391.33 Equivalent of road test. (a) In place of, and as equivalent to, the road test required by § 391.31, a person who seeks to drive...

  7. 49 CFR 391.33 - Equivalent of road test.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 5 2013-10-01 2013-10-01 false Equivalent of road test. 391.33 Section 391.33... AND LONGER COMBINATION VEHICLE (LCV) DRIVER INSTRUCTORS Tests § 391.33 Equivalent of road test. (a) In place of, and as equivalent to, the road test required by § 391.31, a person who seeks to drive...

  8. 49 CFR 391.33 - Equivalent of road test.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 5 2011-10-01 2011-10-01 false Equivalent of road test. 391.33 Section 391.33... AND LONGER COMBINATION VEHICLE (LCV) DRIVER INSTRUCTORS Tests § 391.33 Equivalent of road test. (a) In place of, and as equivalent to, the road test required by § 391.31, a person who seeks to drive...

  9. 49 CFR 391.33 - Equivalent of road test.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 5 2012-10-01 2012-10-01 false Equivalent of road test. 391.33 Section 391.33... AND LONGER COMBINATION VEHICLE (LCV) DRIVER INSTRUCTORS Tests § 391.33 Equivalent of road test. (a) In place of, and as equivalent to, the road test required by § 391.31, a person who seeks to drive...

  10. 12 CFR 28.15 - Capital equivalency deposits.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 12 Banks and Banking 1 2012-01-01 2012-01-01 false Capital equivalency deposits. 28.15 Section 28.15 Banks and Banking COMPTROLLER OF THE CURRENCY, DEPARTMENT OF THE TREASURY INTERNATIONAL BANKING ACTIVITIES Federal Branches and Agencies of Foreign Banks § 28.15 Capital equivalency deposits. (a) Capital equivalency deposits—(1) General....

  11. 46 CFR Appendix A to Part 154 - Equivalent Stress

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 5 2011-10-01 2011-10-01 false Equivalent Stress A Appendix A to Part 154 Shipping...—Equivalent Stress I. Equivalent stress (σ c) is calculated by the following formula or another formula... normal stress in “x” direction. σy=total normal stress in “y” direction. τxy=total shear stress in...

  12. 46 CFR Appendix A to Part 154 - Equivalent Stress

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Equivalent Stress A Appendix A to Part 154 Shipping...—Equivalent Stress I. Equivalent stress (σ c) is calculated by the following formula or another formula... normal stress in “x” direction. σy=total normal stress in “y” direction. τxy=total shear stress in...

  13. Reasons for the Decalage between Identity Conservation and Equivalence Conservation.

    ERIC Educational Resources Information Center

    Gold, Ron

    1983-01-01

    Two experiments investigated which of two factors is responsible for decalage between Piaget's equivalence and identity conservation tasks. Performance of 78 primary school students between 57 and 79 months of age was compared on equivalence and identity tasks and a third task, equivalence I, which retains transitivity requirement of Piaget's task…

  14. Tests of the weak equivalence principle

    NASA Astrophysics Data System (ADS)

    Speake, C. C.; Will, C. M.

    2012-09-01

    The Einstein equivalence principle is the foundation for general relativity and all metric theories of gravity. Of its three tenets—the equality of acceleration of test bodies, or weak equivalence principle; the validity of Lorentz invariance in local freely falling frames; and the position invariance of local physical laws—the weak equivalence principle has played the most important role historically, and continues to be a focus of intense theoretical and experimental investigation. From the probably apocryphal 16th century demonstrations by Galileo at Pisa's leaning tower to the sensitive torsion-balance measurements of today (both pictured on the cover of this issue), this principle, dubbed WEP, has been crucial to the development of gravitation theory. The universality of the rate of acceleration of all types of matter in a gravitational field can be taken as evidence that gravitation is fundamentally determined by the geometry, or metric, of spacetime. Newton began his magnum opus 'The Principia' with a discussion of WEP and his experiments to verify it, while Einstein took WEP for granted in his construction of general relativity, never once referring to the epochal experiments by Baron Eötvös. The classic 1964 experiment of Roll, Krotkov and Dicke ushered in the modern era of high-precision tests, and the search for a 'fifth force' during the late 1980s (instigated, ironically, by purported anomalies in Eötvös's old data) caused the enterprise to pivot from pure tests of the foundation of GR to searches for new physics beyond the standard model of the non-gravitational interactions. Today, the next generation of experimental tests of WEP are being prepared for launch or are being developed, with the goal of reaching unprecedented levels of sensitivity, in search of signatures of interactions inspired by string theory, extra dimensions and other concepts from the world of high-energy physics. At the same time observations continue using lunar laser

  15. New calculations of neutron kerma coefficients and dose equivalent.

    PubMed

    Liu, Zhenzhou; Chen, Jinxiang

    2008-06-01

    For neutron energies ranging from 1 keV to 20 MeV, the kerma coefficients for elements H, C, N, O, light water, and ICRU tissue were deduced respectively from microscopic cross sections and Monte Carlo simulation (MCNP code). The results are consistent within admitted uncertainties with values evaluated by an international group (Chadwick et al 1999 Med. Phys. 26 974-91). The ambient dose equivalent generated in the ISO-recommended neutron field for an Am-Be neutron source (ISO 8529-1: 2001(E)) was obtained from the kerma coefficients and Monte Carlo calculation. In addition, it was calculated directly by multiplying the neutron fluence by the fluence-to-ambient dose conversion coefficients recommended by ICRP (ICRP 1996 ICRP Publication 74 (Oxford: Pergamon)). The two results agree well with each other. The main feature of this work is our Monte Carlo simulation design and the treatments differing from the work of others in the calculation of neutron energy transfer in non-elastic processes. PMID:18495982

  16. Testing the equivalence principle with atomic interferometry

    NASA Astrophysics Data System (ADS)

    Herrmann, Sven; Dittus, Hansjörg; Lämmerzahl, Claus; pre="the" post=""> QUANTUS,

    2012-09-01

    The weak equivalence principle (WEP), that is, the universality of free fall, states that all point-like neutral particles in a gravitational field fall in the same way. This is the basis of the geometrization of the gravitational interaction. Together with further requirements on the behavior of point particles, light propagation and clocks one can show that gravity is modeled by a Riemannian geometry. Since in the quantum domain all objects are extended, it is not clear whether the notion of a WEP in the quantum domain makes sense at all. We show that for matter wave interferometry the notion of WEP still can be given a meaning. We give a short overview over schemes which allows a violation of the WEP and emphasize that there are also schemes which show that there might be violations of the WEP in the quantum regime which are not present classically. This makes a test of the WEP with quantum matter necessary. We also give a brief outline of the efforts made for testing the WEP with interferometry with cold atoms in the Bremen drop tower carried out by the QUANTUS and PRIMUS collaboration.

  17. Enuresis: a functional equivalent of a fetish.

    PubMed

    Calef, V; Weinshel, E M; Renik, O; Mayer, E L

    1980-01-01

    The split in the ego between consciousness and unconsciousness which sometimes eventuates in fetishism can also be clinically manifested in sleep disturbances, depersonalization, dejà vu and a variety of alterations in the sense of reality. It is suggested that this same split comprises the central dynamic mechanism in enuresis. The sleep disturbance which accompanies enuresis involves a confusion between waking and sleeping, sometimes taking the form of a dream that one is awake. Three patients(adult males) revealed in the course of their analyses that they suffered from childhood enuresis accompanied by a sleep disturbance. Milder forms of sleep disturbances persisted into adult life. In these analyses, certain perceptual distortions, difficulties in the sense of reality, and between fantasy and reality, confusions between waking and sleeping, could all be linked to the functional split between consciousness and unconsciousness and eventually to disavowal of the female genitals. The enuresis represented a functional equivalent of the fetish (and it may be that the urinary stream itself actually served as a fetish). Psychological test data from nine enuretic boys were examined as well. This material clearly demonstrated that these boys wished to deny the differences between males and females, that they suffered from sleep disturbances and that they confused reality and fantasy, sleeping and waking. The combined data suggest the existence of a functional split in the ego used in the service of defence, the product of a regressive fixation and a reinstatement of an archaic mode of thought. PMID:7440069

  18. Symmetry, Equivalence and Self-Assembly

    NASA Astrophysics Data System (ADS)

    Douglas, Jack

    2006-03-01

    Molecular self-assembly at equilibrium is central to the formation of many biological structures and the emulation of this process through the creation of synthetic counterparts offers great promise for nanofabrication. The central problems in this field are an understanding of how the symmetry of the interacting particles encodes the geometrical structure of the organized structure and the nature of the thermodynamic transitions involved. Our approach is inspired by the self-assembly of actin, tubulin and icosahedral structures of plant and animal viruses. We observe chain, membrane,`nanotube' and hollow icosahedron structures using `equivalent' particles exhibiting an interplay between directional (dipolar and multi-polar) interactions and short-range (van der Waals) interactions. Specifically, a dipolar potential (continuous rotational symmetry) gives rise to chain formation, while potentials having discrete rotational symmetries (e.g., square quadrupole or triangular ring of dipoles) led to the self-organization of nanotube and icosahedral structures with some resemblance to tubulin and icosahedral viruses. The simulations are compared to theoretical models of molecular self-assembly, especially in the case of dipolar fluids where the corresponding analytic theory of equilibrium polymerization is well developed. These computations give insights into the design elements required for the development of synthetic systems exhibiting this type of organization.

  19. Challenging a culture of racial equivalence.

    PubMed

    Song, Miri

    2014-03-01

    We live at a time when our understandings and conceptualizations of 'racism' are often highly imprecise, broad, and used to describe a wide range of racialized phenomena. In this article, I raise some important questions about how the term racism is used and understood in contemporary British society by drawing on some recent cases of alleged racism in football and politics, many of which have been played out via new media technologies. A broader understanding of racism, through the use of the term 'racialization', has been helpful in articulating a more nuanced and complex understanding of racial incidents, especially of people's (often ambivalent) beliefs and behaviours. However, the growing emphasis upon 'racialization' has led to a conceptualization of racism which increasingly involves multiple perpetrators, victims, and practices without enough consideration of how and why particular interactions and practices constitute racism as such. The trend toward a growing culture of racial equivalence is worrying, as it denudes the idea of racism of its historical basis, severity and power. These frequent and commonplace assertions of racism in the public sphere paradoxically end up trivializing and homogenizing quite different forms of racialized interactions. I conclude that we need to retain the term 'racism', but we need to differentiate more clearly between 'racism' (as an historical and structured system of domination) from the broader notion of 'racialization'. PMID:24697716

  20. Dynamical ensembles equivalence in fluid mechanics

    NASA Astrophysics Data System (ADS)

    Gallavotti, G.

    1997-02-01

    An attempt to put together various theoretical, mathematical, or experimental results recently developed in apparently unrelated subjects. Namely Ruelle's (1980) approach to turbulence, the body of Nosé-Hoover type of molecular dynamics experiments, (Evans and Morriss, 1990; Evans et al., 1993; Bonetto et al., 1996), mathematical results on Lyapunov exponents (the pairing rule, Dressler (1988) and Dettman and Morriss (1995)) and experimental results on them (Sarman et al., 1992; Bohr et al., 1996), theoretical as well as mathematical results on fluctuations, Frisch and Parisi (1984) (multifractality), and Gallavoti and Cohen (1995) (chaotic hypothesis). The key idea that we try to clarify is that of “dynamical ensembles”, as a generalization of the classical “equilibrium ensembles”, arguing that they should be identified with the SRB distributions and that they share several properties with the classical ensembles. Most of the results invoked here did not deal directly with the Navier-Stokes equations and yet they seem to have a lot to do with them (as we shall argue): here the discussion will focus on the Navier-Stokes and dissipative Euler equations with the aim of proposing several experiments apt to test the equivalence of dynamical ensembles and the chaotic hypothesis. The ideas developed, to a great extent, from the efforts put in interpreting the experimental results in (Bonetto et al., 1996).

  1. VERSE - Virtual Equivalent Real-time Simulation

    NASA Technical Reports Server (NTRS)

    Zheng, Yang; Martin, Bryan J.; Villaume, Nathaniel

    2005-01-01

    Distributed real-time simulations provide important timing validation and hardware in the- loop results for the spacecraft flight software development cycle. Occasionally, the need for higher fidelity modeling and more comprehensive debugging capabilities - combined with a limited amount of computational resources - calls for a non real-time simulation environment that mimics the real-time environment. By creating a non real-time environment that accommodates simulations and flight software designed for a multi-CPU real-time system, we can save development time, cut mission costs, and reduce the likelihood of errors. This paper presents such a solution: Virtual Equivalent Real-time Simulation Environment (VERSE). VERSE turns the real-time operating system RTAI (Real-time Application Interface) into an event driven simulator that runs in virtual real time. Designed to keep the original RTAI architecture as intact as possible, and therefore inheriting RTAI's many capabilities, VERSE was implemented with remarkably little change to the RTAI source code. This small footprint together with use of the same API allows users to easily run the same application in both real-time and virtual time environments. VERSE has been used to build a workstation testbed for NASA's Space Interferometry Mission (SIM PlanetQuest) instrument flight software. With its flexible simulation controls and inexpensive setup and replication costs, VERSE will become an invaluable tool in future mission development.

  2. Asymptotic unitary equivalence in C*-algebras

    NASA Astrophysics Data System (ADS)

    Lin, H.; Niu, Z.

    2015-07-01

    Let C = C( X) be the unital C*-algebra of all continuous functions on a finite CW complex X and let A be a unital simple C*-algebra with tracial rank at most one. We show that two unital monomorphisms φ, ψ: C → A are asymptotically unitarily equivalent, i.e., there exists a continuous path of unitaries { u t : t ∈ [0, 1)} ⊂ A such that lim t→1 u* t φ( f) u t = ψ( f) for all f ∈ C( X) if and only if [ φ] = [ ψ] in KK( C, A), τ ◦ φ = τ ◦ ψ for all τ ∈ T( A), and φ † = ψ †, where T( A) is the simplex of tracial states of A and φ †, ψ †: U ∞( C)/ DU ∞( C) → U ∞( A)/ DU ∞( A) are the induced homomorphisms and where U ∞( A) = ∪ k=1 ∞ U( M k ( A)) and U ∞(C) = ∪ k=1 ∞ ( M k ( C)) are usual infinite unitary groups, respectively, and DU ∞( A) and DU ∞( C) are the commutator subgroups of U ∞( A) and U ∞( C), respectively. We actually prove a more general result for the case in which C is any general unital AH-algebra.

  3. Equivalent width evaluation methods for Doppler, Lorentz, and Voigt profiles.

    PubMed

    Habib, Abdel Aziz M; Rammah, Yasser S

    2014-01-01

    An accurate technique has been developed to calculate the equivalent width of absorption lines. The calculations have been carried out for the pure Doppler and pure Lorentz limiting forms of the equivalent width. A novel expression for the equivalent width for Lorentz profile is given from direct integration of the line profile. The more general case of a Voigt profile leads to an analytical formula that permits a rapid estimate of the equivalent width for a wide range of maximum optical depths. The reliability of the approach is verified using a numerical application calculating the equivalent width for nickel resonance lines at 232.0 and 352.3 nm from atomic absorption (AA) measurements. The dependence of equivalent width on the number density of absorbing atoms is also provided. The results obtained for the equivalent width for the Voigt profile were compared with the data in the available literature obtained by different approaches. PMID:24480275

  4. Macrostate equivalence of two general ensembles and specific relative entropies

    NASA Astrophysics Data System (ADS)

    Mori, Takashi

    2016-08-01

    The two criteria of ensemble equivalence, i.e., macrostate equivalence and measure equivalence, are investigated for a general pair of states. Macrostate equivalence implies the two ensembles are indistinguishable by the measurement of macroscopic quantities obeying the large-deviation principle, and measure equivalence means that the specific relative entropy of these two states vanishes in the thermodynamic limit. It is shown that measure equivalence implies a macrostate equivalence for a general pair of states by deriving an inequality connecting the large-deviation rate functions to the specific relative Renyi entropies. The result is applicable to both quantum and classical systems. As applications, a sufficient condition for thermalization, the time scale of quantum dynamics of macrovariables, and the second law with strict irreversibility in a quantum quench are discussed.

  5. Tissue irradiator

    DOEpatents

    Hungate, F.P.; Riemath, W.F.; Bunnell, L.R.

    1975-12-16

    A tissue irradiator is provided for the in-vivo irradiation of body tissue. The irradiator comprises a radiation source material contained and completely encapsulated within vitreous carbon. An embodiment for use as an in- vivo blood irradiator comprises a cylindrical body having an axial bore therethrough. A radioisotope is contained within a first portion of vitreous carbon cylindrically surrounding the axial bore, and a containment portion of vitreous carbon surrounds the radioisotope containing portion, the two portions of vitreous carbon being integrally formed as a single unit. Connecting means are provided at each end of the cylindrical body to permit connections to blood- carrying vessels and to provide for passage of blood through the bore. In a preferred embodiment, the radioisotope is thulium-170 which is present in the irradiator in the form of thulium oxide. A method of producing the preferred blood irradiator is also provided, whereby nonradioactive thulium-169 is dispersed within a polyfurfuryl alcohol resin which is carbonized and fired to form the integral vitreous carbon body and the device is activated by neutron bombardment of the thulium-169 to produce the beta-emitting thulium-170.

  6. An analytic model of neutron ambient dose equivalent and equivalent dose for proton radiotherapy

    PubMed Central

    Zhang, Rui; Pérez-Andújar, Angélica; Fontenot, Jonas D; Taddei, Phillip J; Newhauser, Wayne D

    2010-01-01

    Stray neutrons generated in passively scattered proton therapy are of concern because they increase the risk that a patient will develop a second cancer. Several investigations characterized stray neutrons in proton therapy using experimental measurements and Monte Carlo simulations, but capabilities of analytical methods to predict neutron exposures are less well developed. The goal of this study was to develop a new analytical model to calculate neutron ambient dose equivalent in air and equivalent dose in phantom based on Monte Carlo modeling of a passively scattered proton therapy unit. The accuracy of the new analytical model is superior to a previous analytical model and comparable to the accuracy of typical Monte Carlo simulations and measurements. Predictions from the new analytical model agreed reasonably well with corresponding values predicted by a Monte Carlo code using an anthropomorphic phantom. PMID:21076197

  7. A restricted proof that the weak equivalence principle implies the Einstein equivalence principle

    NASA Technical Reports Server (NTRS)

    Lightman, A. P.; Lee, D. L.

    1973-01-01

    Schiff has conjectured that the weak equivalence principle (WEP) implies the Einstein equivalence principle (EEP). A proof is presented of Schiff's conjecture, restricted to: (1) test bodies made of electromagnetically interacting point particles, that fall from rest in a static, spherically symmetric gravitational field; (2) theories of gravity within a certain broad class - a class that includes almost all complete relativistic theories that have been found in the literature, but with each theory truncated to contain only point particles plus electromagnetic and gravitational fields. The proof shows that every nonmentric theory in the class (every theory that violates EEP) must violate WEP. A formula is derived for the magnitude of the violation. It is shown that WEP is a powerful theoretical and experimental tool for constraining the manner in which gravity couples to electromagnetism in gravitation theories.

  8. Effective dose equivalent on the ninth Shuttle--Mir mission (STS-91)

    NASA Technical Reports Server (NTRS)

    Yasuda, H.; Badhwar, G. D.; Komiyama, T.; Fujitaka, K.

    2000-01-01

    Organ and tissue doses and effective dose equivalent were measured using a life-size human phantom on the ninth Shuttle-Mir Mission (STS-91, June 1998), a 9.8-day spaceflight at low-Earth orbit (about 400 km in altitude and 51.65 degrees in inclination). The doses were measured at 59 positions using a combination of thermoluminescent dosimeters of Mg(2)SiO(4):Tb (TDMS) and plastic nuclear track detectors (PNTD). In correcting the change in efficiency of the TDMS, it was assumed that reduction of efficiency is attributed predominantly to HZE particles with energy greater than 100 MeV nucleon(-1). A conservative calibration curve was chosen for determining LET from the PNTD track-formation sensitivities. The organ and tissue absorbed doses during the mission ranged from 1.7 to 2.7 mGy and varied by a factor of 1.6. The dose equivalent ranged from 3.4 to 5.2 mSv and varied by a factor of 1.5 on the basis of the dependence of Q on LET in the 1990 recommendations of the ICRP. The effective quality factor (Q(e)) varied from 1.7 to 2.4. The dose equivalents for several radiation-sensitive organs, such as the stomach, lung, gonad and breast, were not significantly different from the skin dose equivalent (H(skin)). The effective dose equivalent was evaluated as 4.1 mSv, which was about 90% of the H(skin).

  9. A soft deformable tissue-equivalent phantom for diffuse optical tomography

    NASA Astrophysics Data System (ADS)

    Hebden, Jeremy C.; Price, Ben D.; Gibson, Adam P.; Royle, Gary

    2006-11-01

    A recipe is presented for the manufacture of highly compressible phantoms for diffuse optical tomography. The recipe is based on polyvinyl alcohol (PVA) slime, a viscoelastic fluid which readily deforms under moderate pressure. Scattering particles and absorbing compounds can be added to provide a uniform material with stable and reproducible optical properties. A linear relationship between the concentration of scattering particles (either titanium dioxide or microspheres) and the transport scatter coefficient is demonstrated. Phantoms of an arbitrary size and shape may be produced by containing the slime within a thin latex shell, and a stability over a period of at least 3 months has been established. The deformable phantoms may be used to test and calibrate optical tomography systems designed for use on patients with irregular or variable geometries.

  10. Modelling and calculations of the response of tissue equivalent proportional counter to charged particles.

    PubMed

    Nikjoo, H; Uehara, S; Pinsky, L; Cucinotta, Francis A

    2007-01-01

    Space activities in earth orbit or in deep space pose challenges to the estimation of risk factors for both astronauts and instrumentation. In space, risk from exposure to ionising radiation is one of the main factors limiting manned space exploration. Therefore, characterising the radiation environment in terms of the types of radiations and the quantity of radiation that the astronauts are exposed to is of critical importance in planning space missions. In this paper, calculations of the response of TEPC to protons and carbon ions were reported. The calculations have been carried out using Monte Carlo track structure simulation codes for the walled and the wall-less TEPC counters. The model simulates nonhomogenous tracks in the sensitive volume of the counter and accounts for direct and indirect events. Calculated frequency- and dose-averaged lineal energies 0.3 MeV-1 GeV protons are presented and compared with the experimental data. The calculation of quality factors (QF) were made using individual track histories. Additionally, calculations of absolute frequencies of energy depositions in cylindrical targets, 100 nm height by 100 nm diameter, when randomly positioned and oriented in water irradiated with 1 Gy of protons of energy 0.3-100 MeV, is presented. The distributions show the clustering properties of protons of different energies in a 100 nm by 100 nm cylinder. PMID:17513858

  11. Principle of Spacetime and Black Hole Equivalence

    NASA Astrophysics Data System (ADS)

    Zhang, Tianxi

    2016-06-01

    Modelling the universe without relying on a set of hypothetical entities (HEs) to explain observations and overcome problems and difficulties is essential to developing a physical cosmology. The well-known big bang cosmology, widely accepted as the standard model, stands on two fundamentals, which are Einstein’s general relativity (GR) that describes the effect of matter on spacetime and the cosmological principle (CP) of spacetime isotropy and homogeneity. The field equation of GR along with the Friedmann-Lemaitre-Robertson-Walker (FLRW) metric of spacetime derived from CP generates the Friedmann equation (FE) that governs the development and dynamics of the universe. The big bang theory has made impressive successes in explaining the universe, but still has problems and solutions of them rely on an increasing number of HEs such as inflation, dark matter, dark energy, and so on. Recently, the author has developed a new cosmological model called black hole universe, which, instead of making many those hypotheses, only includes a new single postulate (or a new principle) to the cosmology - Principle of Spacetime and Black Hole Equivalence (SBHEP) - to explain all the existing observations of the universe and overcome all the existing problems in conventional cosmologies. This study thoroughly demonstrates how this newly developed black hole universe model, which therefore stands on the three fundamentals (GR, CP, and SBHEP), can fully explain the universe as well as easily conquer the difficulties according to the well-developed physics, thus, neither needing any other hypotheses nor existing any unsolved difficulties. This work was supported by NSF/REU (Grant #: PHY-1263253) at Alabama A & M University.

  12. Mass, Special Relativity and the Equivalence Principle

    NASA Astrophysics Data System (ADS)

    Vayenas, Constantinos G.; Souentie, Stamatios N.-A.

    The equivalence principle states that inertial mass of a particle, i.e. the ratio of force and acceleration, is equal to the gravitational mass, i.e. equal to the quantity responsible for the gravitational force. Special relativity dictates that this inertial or gravitational mass of a particle equals γ3 m o where m o is the rest mass of the particle and γ(=(1-v2/c2)-1/2) is the Lorentz factor. The latter is unbound when the particle velocity relative to a laboratory observer approaches the speed of light c. This is a well-known result for linear motions and, using instantaneous frames of reference, is shown here to be valid also for arbitrary particle motion. Thus it is the gravitational mass γ3 m o, rather than the relativistic mass, γm o, defined from Einstein's famous E = γm o c 2 which must be used in Newton's gravitational law. This difference is totally negligible for non-relativistic velocities, e.g. v < 0. 1c, but can become quite important when v approaches c. Thus special relativity coupled with Newton's gravitational law dictates that the gravitational attraction becomes much stronger under relativistic conditions than that expected from the simple Newton's gravitational law using the rest, m o, or relativistic mass, γm o of the particles involved. This is consistent with the expectation, based on general relativity, that Newton's gravitational law when used with rest or the relativistic masses, may not be valid under highly relativistic conditions. The implications are quite significant for fast subatomic particles.

  13. Photochemical tissue bonding

    DOEpatents

    Redmond, Robert W.; Kochevar, Irene E.

    2012-01-10

    Photochemical tissue bonding methods include the application of a photosensitizer to a tissue and/or tissue graft, followed by irradiation with electromagnetic energy to produce a tissue seal. The methods are useful for tissue adhesion, such as in wound closure, tissue grafting, skin grafting, musculoskeletal tissue repair, ligament or tendon repair and corneal repair.

  14. Out-of-field photon and neutron dose equivalents from step-and-shoot intensity-modulated radiation therapy

    SciTech Connect

    Kry, Stephen F.; Salehpour, Mohammad . E-mail: msalehpour@mdanderson.org; Followill, David S.; Stovall, Marilyn; Kuban, Deborah A.; White, R. Allen; Rosen, Isaac I.

    2005-07-15

    Purpose: To measure the photon and neutron out-of-treatment-field dose equivalents to various organs from different treatment strategies (conventional vs. intensity-modulated radiation therapy [IMRT]) at different treatment energies and delivered by different accelerators. Methods and Materials: Independent measurements were made of the photon and neutron out-of-field dose equivalents resulting from one conventional and six IMRT treatments for prostate cancer. The conventional treatment used an 18-MV beam from a Clinac 2100; the IMRT treatments used 6-MV, 10-MV, 15-MV, and 18-MV beams from a Varian Clinac 2100 accelerator and 6-MV and 15-MV beams from a Siemens Primus accelerator. Photon doses were measured with thermoluminescent dosimeters in a Rando phantom, and neutron fluence was measured with gold foils. Dose equivalents to the colon, liver, stomach, lung, esophagus, thyroid, and active bone marrow were determined for each treatment approach. Results: For each treatment approach, the relationship between dose equivalent per MU, distance from the treatment field, and depth in the patient was examined. Photon dose equivalents decreased approximately exponentially with distance from the treatment field. Neutron dose equivalents were independent of distance from the treatment field and decreased with increasing tissue depth. Neutrons were a significant contributor to the out-of field dose equivalent for beam energies {>=}15 MV. Conclusions: Out-of-field photon and neutron dose equivalents can be estimated to any point in a patient undergoing a similar treatment approach from the distance of that point to the central axis and from the tissue depth. This information is useful in determining the dose to critical structures and in evaluating the risk of associated carcinogenesis.

  15. Elemental carbon and polycyclic aromatic compounds in a 150-year sediment core from Lake Qinghai, Tibetan Plateau, China: influence of regional and local sources and transport pathways.

    PubMed

    Han, Y M; Wei, C; Bandowe, B A M; Wilcke, W; Cao, J J; Xu, B Q; Gao, S P; Tie, X X; Li, G H; Jin, Z D; An, Z S

    2015-04-01

    Elemental carbon (EC) and polycyclic aromatic compounds (PACs) are potential proxies for the reconstruction of change in human activities and the origin of air masses in historic times. In this study, the historic deposition of char and soot (the two subtypes of EC) and PACs in a 150-year sediment core from different topographic subbasins of Lake Qinghai on the Qinghai Tibetan Plateau (QTP) were reconstructed. The objective was to explore how the variations in the concentrations of EC and PACs, in the ratios of char to soot and of oxygenated polycyclic aromatic hydrocarbons (OPAHs) to parent PAHs, and in the composition of the PAC mixtures reflect historical changes in climate and human activity and the origin of air masses arriving at the QTP. The deposition fluxes of soot in the different subbasins were similar, averaging 0.18 (range of 0.15-0.25) and 0.16 (0.13-0.23) g m(-2) year(-1), respectively, but they varied for char (averaging 0.11 and 0.22 g m(-2) year(-1), respectively), suggesting ubiquitous atmospheric deposition of soot and local river inputs of char. The different vertical distributions of the char/soot ratios in the different subbasins can be interpreted in terms of the different transport mechanisms of char and soot. An abrupt increase in soot concentrations since 1980 coincides with results from the QTP ice cores that were interpreted to be indicative of soot transport from South Asia. Similar concentration patterns of PAHs with soot and 9,10-anthraquinone/anthracene (9,10-AQ/ANT) ratios all >2.0 suggest regional PAC sources. Increasing PAH/soot ratios and decreasing 9,10-AQ/ANT ratios since the beginning of the 1970s indicate increasing local emissions. The historical trends of these diagnostic ratios indicate an increase in the fossil-fuel contribution since the beginning of the 1970s. The increase of perylene concentrations with increasing core depth and the ratio of perylene to its penta-aromatic isomers indicate that perylene originates

  16. Botulinum toxin type a (150 kDa) decreases exaggerated neurotransmitter release from trigeminal ganglion neurons and relieves neuropathy behaviors induced by infraorbital nerve constriction.

    PubMed

    Kitamura, Y; Matsuka, Y; Spigelman, I; Ishihara, Y; Yamamoto, Y; Sonoyama, W; Kamioka, H; Yamashiro, T; Kuboki, T; Oguma, K

    2009-04-10

    Many patients with trigeminal neuropathies suffer severe chronic pain which is inadequately alleviated with centrally-acting drugs. These drugs also possess severe side effects making compliance difficult. One strategy is to develop new treatments without central side effects by targeting peripheral sensory neurons, since sensory neuron excitability and neurotransmitter release increase in chronic pain states. Such treatments may include the highly purified botulinum toxin type A 150 kDa (BoNT/A) which reportedly blocks vesicular neurotransmitter release. We set out to determine if experimental trigeminal neuropathy induced by infraorbital nerve constriction (IoNC) in rats could alter neurotransmitter release from somata of trigeminal sensory neurons and if it could be attenuated by BoNT/A. Thus, we monitored the secretory activity of acutely dissociated trigeminal ganglion (TRG) neurons from naïve and IoNC rats by measuring the fluorescence intensity of the membrane-uptake marker (N-(3-triethylammoniumpropyl)-4-(6-(4-(diethylamino)phenyl)hexatrienyl)pyridinium dibromide (FM4-64). FM4-64 staining showed that neurons possess a pool of recycled vesicles which could be released by high KCl (75 mM) application. BoNT/A pre-treatment of acutely dissociated TRG neurons from naïve rats significantly reduced the rate of FM4-64 dye release. Neurons isolated from TRG ipsilateral to IoNC exhibited significantly faster onset of FM4-64 release than neurons contralateral to IoNC (sham surgery). IoNC also produced long-lasting ipsilateral tactile allodynia, measured as large decreases of withdrawal thresholds to mechanical stimulation. Intradermal injection of BoNT/A in the area of infraorbital branch of the trigeminal nerve (IoN) innervation alleviated IoNC-induced mechanical allodynia and reduced the exaggerated FM4-64 release in TRG neurons from these rats. Our results suggest that BoNT/A decreases neuropathic pain behaviors by decreasing the exaggerated neurotransmitter

  17. EQUIVALENCE BETWEEN SHORT-TIME BIPHASIC AND INCOMPRESSIBLE ELASTIC MATERIAL RESPONSES

    PubMed Central

    Ateshian, Gerard A.; Ellis, Benjamin J.; Weiss, Jeffrey A.

    2009-01-01

    Porous-permeable tissues have often been modeled using porous media theories such as the biphasic theory. This study examines the equivalence of the short-time biphasic and incompressible elastic responses for arbitrary deformations and constitutive relations from first principles. This equivalence is illustrated in problems of unconfined compression of a disk, and of articular contact under finite deformation, using two different constitutive relations for the solid matrix of cartilage, one of which accounts for the large disparity observed between the tensile and compressive moduli in this tissue. Demonstrating this equivalence under general conditions provides a rationale for using available finite element codes for incompressible elastic materials as a practical substitute for biphasic analyses, so long as only the short-time biphasic response is sought. In practice, an incompressible elastic analysis is representative of a biphasic analysis over the short-term response δt≪Δ2/‖C4‖||K||, where Δ is a characteristic dimension, C4 is the elasticity tensor and K is the hydraulic permeability tensor of the solid matrix. Certain notes of caution are provided with regard to implementation issues, particularly when finite element formulations of incompressible elasticity employ an uncoupled strain energy function consisting of additive deviatoric and volumetric components. PMID:17536908

  18. Dose sculpting with generalized equivalent uniform dose

    SciTech Connect

    Wu Qiuwen; Djajaputra, David; Liu, Helen H.; Dong Lei; Mohan, Radhe; Wu, Yan

    2005-05-01

    With intensity-modulated radiotherapy (IMRT), a variety of user-defined dose distribution can be produced using inverse planning. The generalized equivalent uniform dose (gEUD) has been used in IMRT optimization as an alternative objective function to the conventional dose-volume-based criteria. The purpose of this study was to investigate the effectiveness of gEUD optimization to fine tune the dose distributions of IMRT plans. We analyzed the effect of gEUD-based optimization parameters on plan quality. The objective was to determine whether dose distribution to selected structures could be improved using gEUD optimization without adversely altering the doses delivered to other structures, as in sculpting. We hypothesized that by carefully defining gEUD parameters (EUD{sub 0} and n) based on the current dose distributions, the optimization system could be instructed to search for alternative solutions in the neighborhood, and we could maintain the dose distributions for structures already satisfactory and improve dose for structures that need enhancement. We started with an already acceptable IMRT plan optimized with any objective function. The dose distribution was analyzed first. For structures that dose should not be changed, a higher value of n was used and EUD{sub 0} was set slightly higher/lower than the EUD value at the current dose distribution for critical structures/targets. For structures that needed improvement in dose, a higher to medium value of n was used, and EUD{sub 0} was set to the EUD value or slightly lower/higher for the critical structure/target at the current dose distribution. We evaluated this method in one clinical case each of head and neck, lung and prostate cancer. Dose volume histograms, isodose distributions, and relevant tolerance doses for critical structures were used for the assessment. We found that by adjusting gEUD optimization parameters, the dose distribution could be improved with only a few iterations. A larger value of n

  19. Tissue Photolithography

    NASA Technical Reports Server (NTRS)

    Wade, Lawrence A.; Kartalov, Emil; Shibata, Darryl; Taylor, Clive

    2011-01-01

    Tissue lithography will enable physicians and researchers to obtain macromolecules with high purity (greater than 90 percent) from desired cells in conventionally processed, clinical tissues by simply annotating the desired cells on a computer screen. After identifying the desired cells, a suitable lithography mask will be generated to protect the contents of the desired cells while allowing destruction of all undesired cells by irradiation with ultraviolet light. The DNA from the protected cells can be used in a number of downstream applications including DNA sequencing. The purity (i.e., macromolecules isolated form specific cell types) of such specimens will greatly enhance the value and information of downstream applications. In this method, the specific cells are isolated on a microscope slide using photolithography, which will be faster, more specific, and less expensive than current methods. It relies on the fact that many biological molecules such as DNA are photosensitive and can be destroyed by ultraviolet irradiation. Therefore, it is possible to protect the contents of desired cells, yet destroy undesired cells. This approach leverages the technologies of the microelectronics industry, which can make features smaller than 1 micrometer with photolithography. A variety of ways has been created to achieve identification of the desired cell, and also to designate the other cells for destruction. This can be accomplished through chrome masks, direct laser writing, and also active masking using dynamic arrays. Image recognition is envisioned as one method for identifying cell nuclei and cell membranes. The pathologist can identify the cells of interest using a microscopic computerized image of the slide, and appropriate custom software. In one of the approaches described in this work, the software converts the selection into a digital mask that can be fed into a direct laser writer, e.g. the Heidelberg DWL66. Such a machine uses a metalized glass plate (with

  20. Measurement of neutron ambient dose equivalent in passive carbon-ion and proton radiotherapies

    SciTech Connect

    Yonai, Shunsuke; Matsufuji, Naruhiro; Kanai, Tatsuaki; Matsui, Yuki; Matsushita, Kaoru; Yamashita, Haruo; Numano, Masumi; Sakae, Takeji; Terunuma, Toshiyuki; Nishio, Teiji; Kohno, Ryosuke; Akagi, Takashi

    2008-11-15

    Secondary neutron ambient dose equivalents per the treatment absorbed dose in passive carbon-ion and proton radiotherapies were measured using a rem meter, WENDI-II at two carbon-ion radiotherapy facilities and four proton radiotherapy facilities in Japan. Our measured results showed that (1) neutron ambient dose equivalent in carbon-ion radiotherapy is lower than that in proton radiotherapy, and (2) the difference to the measured neutron ambient dose equivalents among the facilities is within a factor of 3 depending on the operational beam setting used at the facility and the arrangement of the beam line, regardless of the method for making a laterally uniform irradiation field: the double scattering method or the single-ring wobbling method. The reoptimization of the beam line in passive particle radiotherapy is an effective way to reduce the risk of secondary cancer because installing an adjustable precollimator and designing the beam line devices with consideration of their material, thickness and location, etc., can significantly reduce the neutron exposure. It was also found that the neutron ambient dose equivalent in passive particle radiotherapy is equal to or less than that in the photon radiotherapy. This result means that not only scanning particle radiotherapy but also passive particle radiotherapy can provide reduced exposure to normal tissues around the target volume without an accompanied increase in total body dose.

  1. 49 CFR 538.8 - Gallon Equivalents for Gaseous Fuels.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... TRAFFIC SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION MANUFACTURING INCENTIVES FOR ALTERNATIVE FUEL... Measurements for Gaseous Fuels per 100 Standard Cubic Feet Fuel Gallon equivalent measurement...

  2. 49 CFR 538.8 - Gallon Equivalents for Gaseous Fuels.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... TRAFFIC SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION MANUFACTURING INCENTIVES FOR ALTERNATIVE FUEL... Measurements for Gaseous Fuels per 100 Standard Cubic Feet Fuel Gallon equivalent measurement...

  3. 49 CFR 538.8 - Gallon Equivalents for Gaseous Fuels.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... TRAFFIC SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION MANUFACTURING INCENTIVES FOR ALTERNATIVE FUEL... Measurements for Gaseous Fuels per 100 Standard Cubic Feet Fuel Gallon equivalent measurement...

  4. 49 CFR 538.8 - Gallon Equivalents for Gaseous Fuels.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... TRAFFIC SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION MANUFACTURING INCENTIVES FOR ALTERNATIVE FUEL... Measurements for Gaseous Fuels per 100 Standard Cubic Feet Fuel Gallon equivalent measurement...

  5. 49 CFR 538.8 - Gallon Equivalents for Gaseous Fuels.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... TRAFFIC SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION MANUFACTURING INCENTIVES FOR ALTERNATIVE FUEL... Measurements for Gaseous Fuels per 100 Standard Cubic Feet Fuel Gallon equivalent measurement...

  6. Estimating Equivalency of Explosives Through A Thermochemical Approach

    SciTech Connect

    Maienschein, J L

    2002-07-08

    The Cheetah thermochemical computer code provides an accurate method for estimating the TNT equivalency of any explosive, evaluated either with respect to peak pressure or the quasi-static pressure at long time in a confined volume. Cheetah calculates the detonation energy and heat of combustion for virtually any explosive (pure or formulation). Comparing the detonation energy for an explosive with that of TNT allows estimation of the TNT equivalency with respect to peak pressure, while comparison of the heat of combustion allows estimation of TNT equivalency with respect to quasi-static pressure. We discuss the methodology, present results for many explosives, and show comparisons with equivalency data from other sources.

  7. Equivalent Plate Analysis of Aircraft Wing with Discrete Source Damage

    NASA Technical Reports Server (NTRS)

    Krishnamurthy, T.; Mason, Brian H.

    2006-01-01

    An equivalent plate procedure is developed to provide a computationally efficient means of matching the stiffness and frequencies of flight vehicle wing structures for prescribed loading conditions. First, the equivalent plate is used to match the stiffness of a stiffened panel without damage and the stiffness of a stiffened panel with damage. For both stiffened panels, the equivalent plate models reproduce the deformation of a corresponding detailed model exactly for the given loading conditions. Once the stiffness was matched, the equivalent plate models were then used to predict the frequencies of the panels. Two analytical procedures using the lumped-mass matrix were used to match the first five frequencies of the corresponding detailed model. In both the procedures, the lumped-mass matrix for the equivalent plate is constructed by multiplying the diagonal terms of the consistent-mass matrix by a proportionality constant. In the first procedure, the proportionality constant is selected such that the total mass of the equivalent plate is equal to that of the detailed model. In the second method, the proportionality constant is selected to minimize the sum of the squares of the errors in a set of pre-selected frequencies between the equivalent plate model and the detailed model. The equivalent plate models reproduced the fundamental first frequency accurately in both the methods. It is observed that changing only the mass distribution in the equivalent plate model did not provide enough flexibility to match all of the frequencies.

  8. Pumpless microfluidic platform for drug testing on human skin equivalents.

    PubMed

    Abaci, Hasan Erbil; Gledhill, Karl; Guo, Zongyou; Christiano, Angela M; Shuler, Michael L

    2015-02-01

    Advances in bio-mimetic in vitro human skin models increase the efficiency of drug screening studies. In this study, we designed and developed a microfluidic platform that allows for long-term maintenance of full thickness human skin equivalents (HSE) which are comprised of both the epidermal and dermal compartments. The design is based on the physiologically relevant blood residence times in human skin tissue and allows for the establishment of an air-epidermal interface which is crucial for maturation and terminal differentiation of HSEs. The small scale of the design reduces the amount of culture medium and the number of cells required by 36 fold compared to conventional transwell cultures. Our HSE-on-a-chip platform has the capability to recirculate the medium at desired flow rates without the need for pump or external tube connections. We demonstrate that the platform can be used to maintain HSEs for three weeks with proliferating keratinocytes similar to conventional HSE cultures. Immunohistochemistry analyses show that the differentiation and localization of keratinocytes was successfully achieved, establishing all sub-layers of the epidermis after one week. Basal keratinocytes located at the epidermal-dermal interface remain in a proliferative state for three weeks. We use a transdermal transport model to show that the skin barrier function is maintained for three weeks. We also validate the capability of the HSE-on-a-chip platform to be used for drug testing purposes by examining the toxic effects of doxorubucin on skin cells and structure. Overall, the HSE-on-a-chip is a user-friendly and cost-effective in vitro platform for drug testing of candidate molecules for skin disorders. PMID:25490891

  9. Equivalent Sensor Radiance Generation and Remote Sensing from Model Parameters. Part 1; Equivalent Sensor Radiance Formulation

    NASA Technical Reports Server (NTRS)

    Wind, Galina; DaSilva, Arlindo M.; Norris, Peter M.; Platnick, Steven E.

    2013-01-01

    In this paper we describe a general procedure for calculating equivalent sensor radiances from variables output from a global atmospheric forecast model. In order to take proper account of the discrepancies between model resolution and sensor footprint the algorithm takes explicit account of the model subgrid variability, in particular its description of the probably density function of total water (vapor and cloud condensate.) The equivalent sensor radiances are then substituted into an operational remote sensing algorithm processing chain to produce a variety of remote sensing products that would normally be produced from actual sensor output. This output can then be used for a wide variety of purposes such as model parameter verification, remote sensing algorithm validation, testing of new retrieval methods and future sensor studies. We show a specific implementation using the GEOS-5 model, the MODIS instrument and the MODIS Adaptive Processing System (MODAPS) Data Collection 5.1 operational remote sensing cloud algorithm processing chain (including the cloud mask, cloud top properties and cloud optical and microphysical properties products.) We focus on clouds and cloud/aerosol interactions, because they are very important to model development and improvement.

  10. The materials used in bone tissue engineering

    SciTech Connect

    Tereshchenko, V. P. Kirilova, I. A.; Sadovoy, M. A.; Larionov, P. M.

    2015-11-17

    Bone tissue engineering looking for an alternative solution to the problem of skeletal injuries. The method is based on the creation of tissue engineered bone tissue equivalent with stem cells, osteogenic factors, and scaffolds - the carriers of these cells. For production of tissue engineered bone equivalent is advisable to create scaffolds similar in composition to natural extracellular matrix of the bone. This will provide optimal conditions for the cells, and produce favorable physico-mechanical properties of the final construction. This review article gives an analysis of the most promising materials for the manufacture of cell scaffolds. Biodegradable synthetic polymers are the basis for the scaffold, but it alone cannot provide adequate physical and mechanical properties of the construction, and favorable conditions for the cells. Addition of natural polymers improves the strength characteristics and bioactivity of constructions. Of the inorganic compounds, to create cell scaffolds the most widely used calcium phosphates, which give the structure adequate stiffness and significantly increase its osteoinductive capacity. Signaling molecules do not affect the physico-mechanical properties of the scaffold, but beneficial effect is on the processes of adhesion, proliferation and differentiation of cells. Biodegradation of the materials will help to fulfill the main task of bone tissue engineering - the ability to replace synthetic construct by natural tissues that will restore the original anatomical integrity of the bone.

  11. The materials used in bone tissue engineering

    NASA Astrophysics Data System (ADS)

    Tereshchenko, V. P.; Kirilova, I. A.; Sadovoy, M. A.; Larionov, P. M.

    2015-11-01

    Bone tissue engineering looking for an alternative solution to the problem of skeletal injuries. The method is based on the creation of tissue engineered bone tissue equivalent with stem cells, osteogenic factors, and scaffolds - the carriers of these cells. For production of tissue engineered bone equivalent is advisable to create scaffolds similar in composition to natural extracellular matrix of the bone. This will provide optimal conditions for the cells, and produce favorable physico-mechanical properties of the final construction. This review article gives an analysis of the most promising materials for the manufacture of cell scaffolds. Biodegradable synthetic polymers are the basis for the scaffold, but it alone cannot provide adequate physical and mechanical properties of the construction, and favorable conditions for the cells. Addition of natural polymers improves the strength characteristics and bioactivity of constructions. Of the inorganic compounds, to create cell scaffolds the most widely used calcium phosphates, which give the structure adequate stiffness and significantly increase its osteoinductive capacity. Signaling molecules do not affect the physico-mechanical properties of the scaffold, but beneficial effect is on the processes of adhesion, proliferation and differentiation of cells. Biodegradation of the materials will help to fulfill the main task of bone tissue engineering - the ability to replace synthetic construct by natural tissues that will restore the original anatomical integrity of the bone.

  12. Equivalent sphere approximations for skin, eye, and blood-forming organs

    SciTech Connect

    Maxson, W.L.; Townsend, L.W.; Bier, S.G.

    1996-12-31

    Throughout the manned spaceflight program, protecting astronauts from space radiation has been the subject of intense study. For interplanetary crews, two main sources of radiation hazards are solar particle events (SPEs) and galactic cosmic rays. For nearly three decades, crew doses and related shielding requirements have been assessed using the assumption that body organ exposures are well approximated by exposures at the center of tissue-equivalent spheres. For the skin and for blood-forming organs (BFOs), these spheres have radii of 0 and 5 cm, respectively. Recent studies indicate that significant overestimation of organ doses occurs if these models are used instead of realistic human geometry models. The use of the latter, however, requires much longer computational times. In this work, the authors propose preliminary revisions to these equivalent sphere approximations that yield more realistic dose estimates.

  13. Rallian "equivalent" cylinders reconsidered: comparisons with literal compartments.

    PubMed

    Goldfinger, M D

    2005-06-01

    In Rall's "equivalent" cylinder morphological-to-electrical transformation, neuronal arborizations are reduced to single unbranched core-conductors. The conventional assumption that such an "equivalent" reconstructs the electrical properties of the fibers it represents was tested directly; electrical properties and responses of "equivalent" cylinders were compared with those of their literal branch constituents for fibers with a single symmetrical bifurcation. The numerical solution methods were validated independently by their accurate reconstruction of the responses of an analog circuit configured with compartmental architecture to solve the cable equation for passive fibers with a symmetrical bifurcation. In passive fibers, "equivalent" cylinders misestimated the spatial distribution of voltage amplitudes and steady-state input resistance, partly due to the lack of axial current bifurcation. In active fibers with a single propagating action potential, the spatial distributions of point-to-point conduction velocity values (measured in meters/second) for a literal branch point differed significantly from those of their "equivalent" cylinders. "Equivalent" cylinders also underestimated the diameter-dependent delay in propagation through the branch point and branches, due to the larger "equivalent" diameter. Corrections to the "equivalent" cylinder did not reconcile differences between "equivalent" and literal models. However, "equivalent" and literal branch fibers had the same (a) steady-state resistance "looking into" an isolated symmetrical branch point and (b) geometry-independent point-to-point propagation velocity when measured in space constants per millisecond except within +/-1 space constant from the geometrical inhomogeneity. In summary, Rall's "equivalent" cylinders did not accurately reconstruct all passive or active electrophysiological properties and responses of their literal compartments. For the modeling of individual neurons, the requirement of

  14. Endogenous human skin equivalent promotes in vitro morphogenesis of follicle-like structures.

    PubMed

    Casale, Costantino; Imparato, Giorgia; Urciuolo, Francesco; Netti, Paolo A

    2016-09-01

    Three-dimensional constructs formed by cells embedded in an exogenous scaffold could not represent a faithful in vitro replica of native and functional tissues. In this work we produced an endogenous human skin equivalent by means of a tissue engineering process that induces the full morphogenesis of functional dermal and epidermal compartments. In such an organotypic context we demonstrated that -by using adult human skin cells-it is possible to generate follicle-like structures in vitro resembling what occurs in vivo in the fetal skin. Immunotypization evidences an inward-oriented differentiation of the follicular-like structures through immunopositivity for epithelial stem cell markers such as p63 and K19. Moreover we detected the presence of versican within the intricate network of the dermal compartment, suggesting its role as an inductive factor for the morphogenesis of appendage-like structures. These results support the importance of the repository and regulatory role of the endogenous extra cellular matrix in guiding tissue morphogenesis. The microenvironment provided by the endogenous human skin equivalent preserves p63 and K19 positive cells and could finally be involved in: (i) triggering the arrangement of the keratinocytes in follicle-like structures; (ii) promoting the convolute profile of the derma-epidermal junction and (iii) improving epidermis barrier function. We argue that the nature of dermal compartment plays a role in directing epithelial cell fate and function in vitro. PMID:27267630

  15. Basis for equivalent fluence concept in space solar cells

    NASA Technical Reports Server (NTRS)

    Meulenberg, A.

    1982-01-01

    The equivalent fluence concept is defined, and its use and potential problems are noted. Silicon and GaAs solar cells are compared in a radiation environment. The analysis indicates that valid equivalent fluence values may be easier to obtain in GaAs than in silicon.

  16. 33 CFR 101.130 - Equivalent security measures.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false Equivalent security measures. 101... MARITIME SECURITY MARITIME SECURITY: GENERAL General § 101.130 Equivalent security measures. (a) For any measure required by part 104, 105, or 106 of this subchapter, the owner or operator may substitute...

  17. 33 CFR 101.130 - Equivalent security measures.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 1 2013-07-01 2013-07-01 false Equivalent security measures. 101... MARITIME SECURITY MARITIME SECURITY: GENERAL General § 101.130 Equivalent security measures. (a) For any measure required by part 104, 105, or 106 of this subchapter, the owner or operator may substitute...

  18. 33 CFR 101.130 - Equivalent security measures.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Equivalent security measures. 101... MARITIME SECURITY MARITIME SECURITY: GENERAL General § 101.130 Equivalent security measures. (a) For any measure required by part 104, 105, or 106 of this subchapter, the owner or operator may substitute...

  19. 33 CFR 101.130 - Equivalent security measures.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 1 2012-07-01 2012-07-01 false Equivalent security measures. 101... MARITIME SECURITY MARITIME SECURITY: GENERAL General § 101.130 Equivalent security measures. (a) For any measure required by part 104, 105, or 106 of this subchapter, the owner or operator may substitute...

  20. 33 CFR 101.130 - Equivalent security measures.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 1 2014-07-01 2014-07-01 false Equivalent security measures. 101... MARITIME SECURITY MARITIME SECURITY: GENERAL General § 101.130 Equivalent security measures. (a) For any measure required by part 104, 105, or 106 of this subchapter, the owner or operator may substitute...

  1. Teaching Statistical Variability with Equivalence-Based Instruction

    ERIC Educational Resources Information Center

    Albright, Leif; Reeve, Kenneth F.; Reeve, Sharon A.; Kisamore, April N.

    2015-01-01

    In the present study, equivalence-based instruction was used to teach 2 4-member classes representing high and low statistical variability to 10 college students. Computerized equivalence-based instruction with multiple-exemplar training was used to teach the classes. A pretest-training-posttest design evaluated performances on both computer-based…

  2. 40 CFR 61.66 - Equivalent equipment and procedures.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... satisfaction to be equivalent in terms of reducing vinyl chloride emissions to the atmosphere to those... (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS National Emission Standard for Vinyl Chloride § 61.66 Equivalent equipment and procedures. Upon written application from an owner or...

  3. 40 CFR 61.66 - Equivalent equipment and procedures.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... satisfaction to be equivalent in terms of reducing vinyl chloride emissions to the atmosphere to those... (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS National Emission Standard for Vinyl Chloride § 61.66 Equivalent equipment and procedures. Upon written application from an owner or...

  4. 40 CFR 61.66 - Equivalent equipment and procedures.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... satisfaction to be equivalent in terms of reducing vinyl chloride emissions to the atmosphere to those... (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS National Emission Standard for Vinyl Chloride § 61.66 Equivalent equipment and procedures. Upon written application from an owner or...

  5. 40 CFR 61.66 - Equivalent equipment and procedures.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... satisfaction to be equivalent in terms of reducing vinyl chloride emissions to the atmosphere to those... (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS National Emission Standard for Vinyl Chloride § 61.66 Equivalent equipment and procedures. Upon written application from an owner or...

  6. 40 CFR 61.66 - Equivalent equipment and procedures.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... satisfaction to be equivalent in terms of reducing vinyl chloride emissions to the atmosphere to those... (CONTINUED) NATIONAL EMISSION STANDARDS FOR HAZARDOUS AIR POLLUTANTS National Emission Standard for Vinyl Chloride § 61.66 Equivalent equipment and procedures. Upon written application from an owner or...

  7. 30 CFR 70.206 - Approved sampling devices; equivalent concentrations.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... concentrations. 70.206 Section 70.206 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF... § 70.206 Approved sampling devices; equivalent concentrations. The concentration of respirable dust... concentration to an equivalent concentration as measured with an MRE instrument. To convert a concentration...

  8. 30 CFR 70.206 - Approved sampling devices; equivalent concentrations.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... concentrations. 70.206 Section 70.206 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF... § 70.206 Approved sampling devices; equivalent concentrations. The concentration of respirable dust... concentration to an equivalent concentration as measured with an MRE instrument. To convert a concentration...

  9. 30 CFR 70.206 - Approved sampling devices; equivalent concentrations.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... concentrations. 70.206 Section 70.206 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF... § 70.206 Approved sampling devices; equivalent concentrations. The concentration of respirable dust... concentration to an equivalent concentration as measured with an MRE instrument. To convert a concentration...

  10. 40 CFR 790.85 - Submission of equivalence data.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 31 2010-07-01 2010-07-01 true Submission of equivalence data. 790.85... Test Rules § 790.85 Submission of equivalence data. If EPA requires in a test rule promulgated under... exemption applicant must submit the following data: (a) The chemical identity of each...

  11. Probability of Equivalence Formation: Familiar Stimuli and Training Sequence

    ERIC Educational Resources Information Center

    Arntzen, Erik

    2004-01-01

    The present study was conducted to show how responding in accord with equivalence relations changes as a function of position of familiar stimuli, pictures, and with the use of nonsense syllables in an MTO-training structure. Fifty college students were tested for responding in accord with equivalence in an AB, CB, DB, and EB training structure.…

  12. The Equivalence of Rater Sources on Job Analysis Ratings.

    ERIC Educational Resources Information Center

    Camara, Wayne J.

    Previous efforts to investigate the equivalence of rating sources for job analysis ratings have reported conflicting results. In the present research, correlational and generalizability analyses were conducted to examine the equivalency of rating sources for over 70 state civil service job classifications. Incumbent and supervisor ratings (N=697)…

  13. Equivalence Class Formation: A Method for Teaching Statistical Interactions

    ERIC Educational Resources Information Center

    Fields, Lanny; Travis, Robert; Roy, Deborah; Yadlovker, Eytan; de Aguiar-Rocha, Liliane; Sturmey, Peter

    2009-01-01

    Many students struggle with statistical concepts such as interaction. In an experimental group, participants took a paper-and-pencil test and then were given training to establish equivalent classes containing four different statistical interactions. All participants formed the equivalence classes and showed maintenance when probes contained novel…

  14. Equivalent Credit. A Guide for Local Discussion and Implementation.

    ERIC Educational Resources Information Center

    Alaska State Dept. of Education, Juneau. Div. of Adult and Vocational Education.

    This guide was developed in Alaska to help high school administrators and teachers determine why and how to grant equivalent credit graduation requirements for vocational courses. The guide is organized in four sections. The first section provides a rationale for the use of equivalent credits, explaining how they benefit students, teachers,…

  15. 30 CFR 70.206 - Approved sampling devices; equivalent concentrations.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... concentrations. 70.206 Section 70.206 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF... § 70.206 Approved sampling devices; equivalent concentrations. The concentration of respirable dust... concentration to an equivalent concentration as measured with an MRE instrument. To convert a concentration...

  16. 30 CFR 70.206 - Approved sampling devices; equivalent concentrations.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... concentrations. 70.206 Section 70.206 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF... § 70.206 Approved sampling devices; equivalent concentrations. The concentration of respirable dust... concentration to an equivalent concentration as measured with an MRE instrument. To convert a concentration...

  17. Assessing Measurement Equivalence in Ordered-Categorical Data

    ERIC Educational Resources Information Center

    Elosua, Paula

    2011-01-01

    Assessing measurement equivalence in the framework of the common factor linear models (CFL) is known as factorial invariance. This methodology is used to evaluate the equivalence among the parameters of a measurement model among different groups. However, when dichotomous, Likert, or ordered responses are used, one of the assumptions of the CFL is…

  18. Guidelines for Equivalent Instruction through Home-Schooling.

    ERIC Educational Resources Information Center

    Boose, Robert E.

    Maine law allows parents to arrange with local school boards to have their children educated outside a public or private school, if the student will receive "equivalent instruction." If the proposed program of instruction is "equivalent" within the meaning of the law, it must be approved by local school officials. Parents are entitled to a fair…

  19. Mechanical Equivalent of Heat--Software for a Thermistor

    ERIC Educational Resources Information Center

    Boleman, Michael

    2008-01-01

    The Mechanical Equivalent of Heat Apparatus from PASCO scientific provides the means for doing a simple experiment to determine the mechanical equivalent of heat, "J." A necessary step of this experiment is to determine the temperature of an aluminum cylinder. By measuring the resistance of a thermistor embedded in the cylinder, one is able to…

  20. 40 CFR 133.105 - Treatment equivalent to secondary treatment.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 23 2012-07-01 2012-07-01 false Treatment equivalent to secondary treatment. 133.105 Section 133.105 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) WATER PROGRAMS SECONDARY TREATMENT REGULATION § 133.105 Treatment equivalent to secondary...

  1. 40 CFR 133.105 - Treatment equivalent to secondary treatment.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 23 2013-07-01 2013-07-01 false Treatment equivalent to secondary treatment. 133.105 Section 133.105 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) WATER PROGRAMS SECONDARY TREATMENT REGULATION § 133.105 Treatment equivalent to secondary...

  2. 40 CFR 133.105 - Treatment equivalent to secondary treatment.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 22 2011-07-01 2011-07-01 false Treatment equivalent to secondary treatment. 133.105 Section 133.105 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) WATER PROGRAMS SECONDARY TREATMENT REGULATION § 133.105 Treatment equivalent to secondary...

  3. 40 CFR 133.105 - Treatment equivalent to secondary treatment.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 21 2010-07-01 2010-07-01 false Treatment equivalent to secondary treatment. 133.105 Section 133.105 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) WATER PROGRAMS SECONDARY TREATMENT REGULATION § 133.105 Treatment equivalent to secondary...

  4. 40 CFR 133.105 - Treatment equivalent to secondary treatment.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 22 2014-07-01 2013-07-01 true Treatment equivalent to secondary treatment. 133.105 Section 133.105 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) WATER PROGRAMS SECONDARY TREATMENT REGULATION § 133.105 Treatment equivalent to secondary...

  5. Neutron detector simultaneously measures fluence and dose equivalent

    NASA Technical Reports Server (NTRS)

    Dvorak, R. F.; Dyer, N. C.

    1967-01-01

    Neutron detector acts as both an area monitoring instrument and a criticality dosimeter by simultaneously measuring dose equivalent and fluence. The fluence is determined by activation of six foils one inch below the surface of the moderator. Dose equivalent is determined from activation of three interlocked foils at the center of the moderator.

  6. Nodal Structure and the Partitioning of Equivalence Classes

    ERIC Educational Resources Information Center

    Fields, Lanny; Watanabe-Rose, Mari

    2008-01-01

    By definition, all of the stimuli in an equivalence class have to be functionally interchangeable with each other. The present experiment, however, demonstrated that this was not the case when using post-class-formation dual-option response transfer tests. With college students, two 4-node 6-member equivalence classes with nodal structures of…

  7. 14 CFR 21.261 - Equivalent safety provisions.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 1 2010-01-01 2010-01-01 false Equivalent safety provisions. 21.261 Section 21.261 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION....261 Equivalent safety provisions. The manufacturer shall obtain the Administrator's concurrence on...

  8. 26 CFR 1.871-15 - Treatment of dividend equivalents.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 26 Internal Revenue 9 2014-04-01 2014-04-01 false Treatment of dividend equivalents. 1.871-15 Section 1.871-15 Internal Revenue INTERNAL REVENUE SERVICE, DEPARTMENT OF THE TREASURY (CONTINUED) INCOME... Treatment of dividend equivalents. (a) through (c) (d) Specified NPCs—(1) Specified NPCs before January...

  9. Unitary equivalent classes of one-dimensional quantum walks

    NASA Astrophysics Data System (ADS)

    Ohno, Hiromichi

    2016-06-01

    This study investigates unitary equivalent classes of one-dimensional quantum walks. We prove that one-dimensional quantum walks are unitary equivalent to quantum walks of Ambainis type and that translation-invariant one-dimensional quantum walks are Szegedy walks. We also present a necessary and sufficient condition for a one-dimensional quantum walk to be a Szegedy walk.

  10. Some equivalences between the auxiliary field method and envelope theory

    SciTech Connect

    Buisseret, Fabien; Semay, Claude; Silvestre-Brac, Bernard

    2009-03-15

    The auxiliary field method has been recently proposed as an efficient technique to compute analytical approximate solutions of eigenequations in quantum mechanics. We show that the auxiliary field method is completely equivalent to the envelope theory, which is another well-known procedure to analytically solve eigenequations, although relying on different principles a priori. This equivalence leads to a deeper understanding of both frameworks.

  11. Equivalent Circuit of a Heterostructure with Multiple Quantum Wells

    NASA Astrophysics Data System (ADS)

    Davydov, V. N.; Novikov, D. A.

    2015-11-01

    Based on the consideration of physical processes in a heterostructure with quantum wells (QW), its equivalent circuit is constructed including a barrier capacitance and a differential resistance of the p-n junction, capacitance and resistance of charge relaxation in QW, and resistance of free charge carrier delivery to QW. Analytical expressions for the equivalent capacity and equivalent resistance of the heterostructure for a serial substitution circuit are derived, and behavior of the equivalent parameters attendant to changes of the test signal frequency is analyzed. Results of experimental investigation of the capacitive and resistive properties of the heterostructures with QW based on the InGaN/GaN barriers confirm the calculated dependences of their equivalent parameters and demonstrate their dependence on the special features of the kinetic properties of the heterostructures.

  12. Quantifying the Combined Effect of Radiation Therapy and Hyperthermia in Terms of Equivalent Dose Distributions

    SciTech Connect

    Kok, H. Petra; Crezee, Johannes; Franken, Nicolaas A.P.; Barendsen, Gerrit W.

    2014-03-01

    Purpose: To develop a method to quantify the therapeutic effect of radiosensitization by hyperthermia; to this end, a numerical method was proposed to convert radiation therapy dose distributions with hyperthermia to equivalent dose distributions without hyperthermia. Methods and Materials: Clinical intensity modulated radiation therapy plans were created for 15 prostate cancer cases. To simulate a clinically relevant heterogeneous temperature distribution, hyperthermia treatment planning was performed for heating with the AMC-8 system. The temperature-dependent parameters α (Gy{sup −1}) and β (Gy{sup −2}) of the linear–quadratic model for prostate cancer were estimated from the literature. No thermal enhancement was assumed for normal tissue. The intensity modulated radiation therapy plans and temperature distributions were exported to our in-house-developed radiation therapy treatment planning system, APlan, and equivalent dose distributions without hyperthermia were calculated voxel by voxel using the linear–quadratic model. Results: The planned average tumor temperatures T90, T50, and T10 in the planning target volume were 40.5°C, 41.6°C, and 42.4°C, respectively. The planned minimum, mean, and maximum radiation therapy doses were 62.9 Gy, 76.0 Gy, and 81.0 Gy, respectively. Adding hyperthermia yielded an equivalent dose distribution with an extended 95% isodose level. The equivalent minimum, mean, and maximum doses reflecting the radiosensitization by hyperthermia were 70.3 Gy, 86.3 Gy, and 93.6 Gy, respectively, for a linear increase of α with temperature. This can be considered similar to a dose escalation with a substantial increase in tumor control probability for high-risk prostate carcinoma. Conclusion: A model to quantify the effect of combined radiation therapy and hyperthermia in terms of equivalent dose distributions was presented. This model is particularly instructive to estimate the potential effects of interaction from different

  13. Equivalence of MammaPrint array types in clinical trials and diagnostics.

    PubMed

    Beumer, Inès; Witteveen, Anke; Delahaye, Leonie; Wehkamp, Diederik; Snel, Mireille; Dreezen, Christa; Zheng, John; Floore, Arno; Brink, Guido; Chan, Bob; Linn, Sabine; Bernards, Rene; van 't Veer, Laura; Glas, Annuska

    2016-04-01

    MammaPrint is an FDA-cleared microarray-based test that uses expression levels of the 70 MammaPrint genes to assess distant recurrence risk in early-stage breast cancer. The prospective RASTER study proved that MammaPrint Low Risk patients can safely forgo chemotherapy, which is further subject of the prospective randomized MINDACT trial. While MammaPrint diagnostic results are obtained from mini-arrays, clinical trials may be performed on whole-genome arrays. Here we demonstrate the equivalence and reproducibility of the MammaPrint test. MammaPrint indices were collected for breast cancer samples: (i) on both customized certified array types (n = 1,897 sample pairs), (ii) with matched fresh and FFPE tissues (n = 552 sample pairs), iii) for control samples replicated over a period of 10 years (n = 11,333), and iv) repeated measurements (n = 280). The array type indicated a near perfect Pearson correlation of 0.99 (95 % CI: 0.989-0.991). Paired fresh and FFPE samples showed an excellent Pearson correlation of 0.93 (95 % CI 0.92-0.94), in spite of the variability introduced by intratumoral tissue heterogeneity. Control samples showed high consistency over 10 year's time (overall reproducibility of 97.4 %). Precision and repeatability are overall 98.2 and 98.3 %, respectively. Results confirm that the combination of the near perfect correlation between array types, excellent equivalence between tissue types, and a very high stability, precision, and repeatability demonstrate that results from clinical trials (such as MINDACT and I-SPY 2) are equivalent to current MammaPrint FFPE and fresh diagnostics, and can be used interchangeably. PMID:27002507

  14. Investigating the protective properties of milk phospholipids against ultraviolet light exposure in a skin equivalent model

    NASA Astrophysics Data System (ADS)

    Russell, Ashley; Laubscher, Andrea; Jimenez-Flores, Rafael; Laiho, Lily H.

    2010-02-01

    Current research on bioactive molecules in milk has documented health advantages of bovine milk and its components. Milk Phospholipids, selected for this study, represent molecules with great potential benefit in human health and nutrition. In this study we used confocal reflectance and multiphoton microscopy to monitor changes in skin morphology upon skin exposure to ultraviolet light and evaluate the potential of milk phospholipids in preventing photodamage to skin equivalent models. The results suggest that milk phospholipids act upon skin cells in a protective manner against the effect of ultraviolet (UV) radiation. Similar results were obtained from MTT tissue viability assay and histology.

  15. Study of density and stability of a lung-equivalent gel

    NASA Astrophysics Data System (ADS)

    Claeys, Carolien; de Deene, Yves; Truyens, Bart; de Wagter, Carlos

    2006-12-01

    Gel dosimetry is a useful tool for the verification of radiation treatments in water-equivalent tissues. In order to extend the application of gel dosimetry to the lung, the density of the dosimeter should be reduced. Some methods have been proposed for the fabrication of low-density gels. Major challenges in the fabrication of these gel dosimeters are to achieve a density that equals the electron-density of lung tissue and to obtain an acceptable homogeneity. Both polymer and Fricke gel formulations have been used as basic chemical compositions for low-density gel dosimeters. To reduce the density, two approaches have been suggested: (1) Styrofoam beads can be added to the gel or (2) the gel can be beaten until a foam is obtained. In this study we followed the latter method and added sodium-dodecyl-sulphate (SDS) as a surfactant to increase the surface tension of the gel.

  16. Multivariate equivalence tests for use in pharmaceutical development.

    PubMed

    Hoffelder, Thomas; Gössl, Rüdiger; Wellek, Stefan

    2015-01-01

    Statistical equivalence analyses are well-established parts of many studies in the biomedical sciences. Also in pharmaceutical development and manufacturing equivalence testing methods are required in order to statistically establish similarities between machines, process components, or complete processes. This article presents a choice of multivariate equivalence testing procedures for normally distributed data as generalizations of existing univariate methods. In all derived methods, variability is interpreted as nuisance parameter. The use of the proposed methods in pharmaceutical development is demonstrated with a comparative analysis of dissolution profiles. PMID:24896319

  17. Weight propagation and equivalent horsepower for alternate-engined cars

    NASA Technical Reports Server (NTRS)

    Klose, G. J.; Kurtz, D. W.

    1978-01-01

    In order to evaluate properly the consequences of replacing conventional Otto-cycle engines with alternate power systems, comparisons must be carried out at the vehicle level with functionally equivalent cars. This paper presents the development and application of a procedure for establishing equivalent vehicles. A systematic weight propagation methodology, based on detailed weight breakdowns and influence factors, yields the vehicle weight impacts due to changes in engine weight and power. Performance-matching criteria, utilizing a vehicle simulation program, are then employed to establish Otto-engine-equivalent vehicles, whose characteristics can form the basis for alternative engine evaluations.

  18. Singularity theory of fitness functions under dimorphism equivalence.

    PubMed

    Wang, Xiaohui; Golubitsky, Martin

    2016-09-01

    We apply singularity theory to classify monomorphic singular points as they occur in adaptive dynamics. Our approach is based on a new equivalence relation called dimorphism equivalence, which is the largest equivalence relation on strategy functions that preserves ESS singularities, CvSS singularities, and dimorphisms. Specifically, we classify singularities up to topological codimension two and compute their normal forms and universal unfoldings. These calculations lead to the classification of local mutual invasibility plots that can be seen generically in systems with two parameters. PMID:26733311

  19. Thévenin equivalence in disorderless quantum networks

    SciTech Connect

    Cain, C. A.; Wu, C. H.

    2015-01-14

    We outline the procedure of extending the Thévenin equivalence principle for classical electric circuits to reducing Aharonov-Bohm-based quantum networks into equivalent models. With examples, we show from first principles how the requirements are related to the electron band structure's Fermi level and the lattice spacing of the network. Quantum networks of varying degrees of coupling strength from four basic classifications of single and double entangled loops sharing symmetry and highly correlated band structures are used to demonstrate the concept. We show the limitations of how the principle may be applied. Several classes of examples are given and their equivalent forms are shown.

  20. Water equivalence of micelle gels for x-ray beams

    NASA Astrophysics Data System (ADS)

    Gorjiara, T.; Hill, R.; Kuncic, Z.; Bosi, S.; Baldock, C.

    2013-06-01

    Micelle gel is a radiochromic hydrogel with the potential to be used as a three dimensional (3D) radiation dosimeter. Since an ideal dosimeter should present water equivalent properties, in this study the water equivalence of two formulations of micelle gel has been investigated by calculating electron density, effective atomic number, fractional interaction probabilities, mass attenuation coefficient. The depth doses for kilovoltage and megavoltage x-ray beams have also modelled using Monte Carlo code. Based on the results of this work, micelle gels can be considered as water equivalent dosimeters.