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Sample records for relative density microstructure

  1. Measurement of carbon nanotube microstructure relative density by optical attenuation and observation of size-dependent variations.

    Science.gov (United States)

    Park, Sei Jin; Schmidt, Aaron J; Bedewy, Mostafa; Hart, A John

    2013-07-21

    Engineering the density of carbon nanotube (CNT) forest microstructures is vital to applications such as electrical interconnects, micro-contact probes, and thermal interface materials. For CNT forests on centimeter-scale substrates, weight and volume can be used to calculate density. However, this is not suitable for smaller samples, including individual microstructures, and moreover does not enable mapping of spatial density variations within the forest. We demonstrate that the relative mass density of individual CNT microstructures can be measured by optical attenuation, with spatial resolution equaling the size of the focused spot. For this, a custom optical setup was built to measure the transmission of a focused laser beam through CNT microstructures. The transmittance was correlated with the thickness of the CNT microstructures by Beer-Lambert-Bouguer law to calculate the attenuation coefficient. We reveal that the density of CNT microstructures grown by CVD can depend on their size, and that the overall density of arrays of microstructures is affected significantly by run-to-run process variations. Further, we use the technique to quantify the change in CNT microstructure density due to capillary densification. This is a useful and accessible metrology technique for CNTs in future microfabrication processes, and will enable direct correlation of density to important properties such as stiffness and electrical conductivity.

  2. Microstructure characterization via stereological relations — A shortcut for beginners

    Energy Technology Data Exchange (ETDEWEB)

    Pabst, Willi, E-mail: pabstw@vscht.cz; Gregorová, Eva; Uhlířová, Tereza

    2015-07-15

    Stereological relations that can be routinely applied for the quantitative characterization of microstructures of heterogeneous single- and two-phase materials via global microstructural descriptors are reviewed. It is shown that in the case of dense, single-phase polycrystalline materials (e.g., transparent yttrium aluminum garnet ceramics) two quantities have to be determined, the interface density (or, equivalently, the mean chord length of the grains) and the mean curvature integral density (or, equivalently, the Jeffries grain size), while for two-phase materials (e.g., highly porous, cellular alumina ceramics), one additional quantity, the volume fraction (porosity), is required. The Delesse–Rosiwal law is recalled and size measures are discussed. It is shown that the Jeffries grain size is based on the triple junction line length density, while the mean chord length of grains is based on the interface density (grain boundary area density). In contrast to widespread belief, however, these two size measures are not alternative, but independent (and thus complementary), measures of grain size. Concomitant with this fact, a clear distinction between linear and planar grain size numbers is proposed. Finally, based on our concept of phase-specific quantities, it is shown that under certain conditions it is possible to define a Jeffries size also for two-phase materials and that the ratio of the mean chord length and the Jeffries size has to be considered as an invariant number for a certain type of microstructure, i.e., a characteristic value that is independent of the absolute size of the microstructural features (e.g., grains, inclusions or pores). - Highlights: • Stereology-based image analysis is reviewed, including error considerations. • Recipes are provided for measuring global metric microstructural descriptors. • Size measures are based on interface density and mean curvature integral density. • Phase-specific quantities and a generalized

  3. Microstructure characterisation of solid oxide electrolysis cells operated at high current density

    DEFF Research Database (Denmark)

    Bowen, Jacob R.; Bentzen, Janet Jonna; Chen, Ming

    degradation of cell components in relation to the loss of electrochemical performance specific to the mode of operation. Thus descriptive microstructure characterization methods are required in combination with electrochemical characterization methods to decipher degradation mechanisms. In the present work......High temperature solid oxide cells can be operated either as fuel cells or electrolysis cells for efficient power generation or production of hydrogen from steam or synthesis gas (H2 + CO) from steam and CO2 respectively. When operated under harsh conditions, they often exhibit microstructural...... quantified using the mean linear intercept method as a function of current density and correlated to increases in serial resistance. The above structural changes are then compared in terms of electrode degradation observed during the co-electrolysis of steam and CO2 at current densities up to -1.5 A cm-2...

  4. Application of High-Density Electropulsing to Improve the Performance of Metallic Materials: Mechanisms, Microstructure and Properties

    Directory of Open Access Journals (Sweden)

    Yinying Sheng

    2018-01-01

    Full Text Available The technology of high-density electropulsing has been applied to increase the performance of metallic materials since the 1990s and has shown significant advantages over traditional heat treatment in many aspects. However, the microstructure changes in electropulsing treatment (EPT metals and alloys have not been fully explored, and the effects vary significantly on different material. When high-density electrical pulses are applied to metals and alloys, the input of electric energy and thermal energy generally leads to structural rearrangements, such as dynamic recrystallization, dislocation movements and grain refinement. The enhanced mechanical properties of the metals and alloys after high-density electropulsing treatment are reflected by the significant improvement of elongation. As a result, this technology holds great promise in improving the deformation limit and repairing cracks and defects in the plastic processing of metals. This review summarizes the effect of high-density electropulsing treatment on microstructural properties and, thus, the enhancement in mechanical strength, hardness and corrosion performance of metallic materials. It is noteworthy that the change of some properties can be related to the structure state before EPT (quenched, annealed, deformed or others. The mechanisms for the microstructural evolution, grain refinement and formation of oriented microstructures of different metals and alloys are presented. Future research trends of high-density electrical pulse technology for specific metals and alloys are highlighted.

  5. Application of High-Density Electropulsing to Improve the Performance of Metallic Materials: Mechanisms, Microstructure and Properties.

    Science.gov (United States)

    Sheng, Yinying; Hua, Youlu; Wang, Xiaojian; Zhao, Xueyang; Chen, Lianxi; Zhou, Hanyu; Wang, James; Berndt, Christopher C; Li, Wei

    2018-01-24

    The technology of high-density electropulsing has been applied to increase the performance of metallic materials since the 1990s and has shown significant advantages over traditional heat treatment in many aspects. However, the microstructure changes in electropulsing treatment (EPT) metals and alloys have not been fully explored, and the effects vary significantly on different material. When high-density electrical pulses are applied to metals and alloys, the input of electric energy and thermal energy generally leads to structural rearrangements, such as dynamic recrystallization, dislocation movements and grain refinement. The enhanced mechanical properties of the metals and alloys after high-density electropulsing treatment are reflected by the significant improvement of elongation. As a result, this technology holds great promise in improving the deformation limit and repairing cracks and defects in the plastic processing of metals. This review summarizes the effect of high-density electropulsing treatment on microstructural properties and, thus, the enhancement in mechanical strength, hardness and corrosion performance of metallic materials. It is noteworthy that the change of some properties can be related to the structure state before EPT (quenched, annealed, deformed or others). The mechanisms for the microstructural evolution, grain refinement and formation of oriented microstructures of different metals and alloys are presented. Future research trends of high-density electrical pulse technology for specific metals and alloys are highlighted.

  6. Application of High-Density Electropulsing to Improve the Performance of Metallic Materials: Mechanisms, Microstructure and Properties

    Science.gov (United States)

    Sheng, Yinying; Hua, Youlu; Zhao, Xueyang; Chen, Lianxi; Zhou, Hanyu; Wang, James; Berndt, Christopher C.; Li, Wei

    2018-01-01

    The technology of high-density electropulsing has been applied to increase the performance of metallic materials since the 1990s and has shown significant advantages over traditional heat treatment in many aspects. However, the microstructure changes in electropulsing treatment (EPT) metals and alloys have not been fully explored, and the effects vary significantly on different material. When high-density electrical pulses are applied to metals and alloys, the input of electric energy and thermal energy generally leads to structural rearrangements, such as dynamic recrystallization, dislocation movements and grain refinement. The enhanced mechanical properties of the metals and alloys after high-density electropulsing treatment are reflected by the significant improvement of elongation. As a result, this technology holds great promise in improving the deformation limit and repairing cracks and defects in the plastic processing of metals. This review summarizes the effect of high-density electropulsing treatment on microstructural properties and, thus, the enhancement in mechanical strength, hardness and corrosion performance of metallic materials. It is noteworthy that the change of some properties can be related to the structure state before EPT (quenched, annealed, deformed or others). The mechanisms for the microstructural evolution, grain refinement and formation of oriented microstructures of different metals and alloys are presented. Future research trends of high-density electrical pulse technology for specific metals and alloys are highlighted. PMID:29364844

  7. Microstructure and critical current density in high-Tc metal oxide superconductors

    International Nuclear Information System (INIS)

    Johnson, S.M.; Gusman, M.I.

    1992-03-01

    Superconductor powders in the U-Ba-Cu-O (YBCO) and Bi-Pb-Sr-Ca-Cu-O (BSCCO) systems were synthesized by freeze-drying. Powders were characterized, and processed into samples for evaluation of superconducting behavior. Freeze-drying is attractive because the powders have high purity, are homogeneous, have a small size and are active. YBCO powders can be sintered to high density at 890 degrees C. Many compositions, processing approaches and heat treatments were explored in an effort to understand relations between microstructure and critical density, and to improve the critical current density. Powders were also formed into sputtering targets for coating preparation at Stanford University. The highest critical current density achieved with the YBCO powders was ∼15,000 A/cm 2 at 4.2K and 0.5T using powders treated to prevent carbon contamination. The BSCCO materials with the highest critical current density, ∼30,000 A/cm 2 at the same conditions were formed by heat treating melted and quenched samples. All critical current density measurements were made by Stanford University, a subcontractor to this effort. Stanford University also prepared coatings by off-axis magnetron sputtering

  8. Vibronic coupling density and related concepts

    International Nuclear Information System (INIS)

    Sato, Tohru; Uejima, Motoyuki; Iwahara, Naoya; Haruta, Naoki; Shizu, Katsuyuki; Tanaka, Kazuyoshi

    2013-01-01

    Vibronic coupling density is derived from a general point of view as a one-electron property density. Related concepts as well as their applications are presented. Linear and nonlinear vibronic coupling density and related concepts, orbital vibronic coupling density, reduced vibronic coupling density, atomic vibronic coupling constant, and effective vibronic coupling density, illustrate the origin of vibronic couplings and enable us to design novel functional molecules or to elucidate chemical reactions. Transition dipole moment density is defined as an example of the one-electron property density. Vibronic coupling density and transition dipole moment density open a way to design light-emitting molecules with high efficiency.

  9. Density limits imposed by the microstructure of magnetic recording media

    International Nuclear Information System (INIS)

    Richter, H.J.

    2009-01-01

    The fundamental limit of magnetic recording density on conventional media is set by the grain size. Once this grain size limit is reached, only a reduction of the grain size allows an increased SNR and thus an increased areal density. It is shown that, whilst maintaining thermal stability, scaling demands that the required anisotropy energy density K is proportional to the areal density, or the square of the areal density if the medium thickness reaches the critical thickness 4√(A/K) (A is the exchange stiffness of the material). Recording onto materials with such a high anisotropy requires some form of a write-assist. It is furthermore shown that the grain size limit cannot be obtained with intergranular exchange present, and six different requirements are listed that constitute ideal media. An alternative path for increasing areal density of magnetic recording is to use patterned media, where each bit contains only one grain. In this case, written-in errors dominate system performance and the maximum achievable areal density is estimated to be about 6 Tbit/in 2 . Patterned media need to exhibit narrow distributions of their physical and structural properties with standard deviations of the order of 5% or less

  10. Relating microstructures to SCC in Inconel 718

    International Nuclear Information System (INIS)

    Sheth, N.K.; Sanchez, J.M.; Hendrix, B.C.; Ide, H.; Miglin, M.T.

    1993-01-01

    Inconel 718, a nickel-iron-base superalloy, is used for stressed applications in the nuclear and oil industries. A major concern facing the continued and expanding use of Inconel 718 in these applications has been their susceptibility to Inter-Granular Stress Corrosion Cracking (IGSCC). Efforts to reduce stress corrosion cracking (SCC) have been aimed at reducing the susceptibility in this alloy to the formation of the deleterious delta (Ni 3 Nb) phase. Microstructural evaluation of SCC test specimens of different thermo-mechanical histories shows that inhomogeneities of all types, including carbides, nitrides, and different morphologies of δ phase, worsen the SCC resistance of IN718. Here the authors study five samples of IN718 with measured hardness and SCC growth rates. A preliminary ranking of the factors mentioned above on SCC resistance finds that precipitation of a fine δ phase, due to over-aging, has the most profound effect on SCC susceptibility of IN718

  11. Flux Density through Guides with Microstructured Twisted Clad DB Medium

    Directory of Open Access Journals (Sweden)

    M. A. Baqir

    2014-01-01

    Full Text Available The paper deals with the study of flux density through a newly proposed twisted clad guide containing DB medium. The inner core and the outer clad sections are usual dielectrics, and the introduced twisted windings at the core-clad interface are treated under DB boundary conditions. The pitch angle of twist is supposed to greatly contribute towards the control over the dispersion characteristics of the guide. The eigenvalue equation for the guiding structure is deduced, and the analytical investigations are made to explore the propagation patterns of flux densities corresponding to the sustained low-order hybrid modes under the situation of varying pitch angles. The emphasis has been put on the effects due to the DB twisted pitch on the propagation of energy flux density through the guide.

  12. Age-related variations in the microstructure of human tibial cancellous bone

    DEFF Research Database (Denmark)

    Ding, M.; Odgaard, A.; Linde, F.

    2002-01-01

    -related changes in the three-dimensional (3D) microstructure of human tibial cancellous bone. One hundred and sixty cylindrical cancellous bone specimens were produced from 40 normal proximal tibiae from 40 donors, aged 16-85 years. These specimens were micro-computed tomography (micro-CT) scanned......, and microstructural properties were determined. The specimens were then tested in compression to obtain Young's modulus. The degree of anisotropy, mean marrow space volume, and bone surface-to-volume ratio increased significantly with age. Bone volume fraction, mean trabecular volume, and bone surface density...

  13. Microstructural factors influencing critical-current densities of high-temperature superconductors

    International Nuclear Information System (INIS)

    Suenaga, M.

    1992-01-01

    Microstructural defects are the primary determining factors for the values of critical current densities in superconductors. A review is made to assess, (1) what would be the maximum achievable critical-current density in the oxide superconductors if nearly ideal pinning sites were introduced? and (2) what types of pinning defects are currently introduced in these superconductors and how effective are these in pinning the vortices? Only the case where the applied field is parallel to the c-axis is considered here

  14. Effect of Target Density on Microstructural, Electrical, and Optical Properties of Indium Tin Oxide Thin Films

    Science.gov (United States)

    Zhu, Guisheng; Zhi, Li; Yang, Huijuan; Xu, Huarui; Yu, Aibing

    2012-09-01

    In this paper, indium tin oxide (ITO) targets with different densities were used to deposit ITO thin films. The thin films were deposited from these targets at room temperature and annealed at 750°C. Microstructural, electrical, and optical properties of the as-prepared films were studied. It was found that the target density had no effect on the properties or deposition rate of radiofrequency (RF)-sputtered ITO thin films, different from the findings for direct current (DC)-sputtered films. Therefore, when using RF sputtering, the target does not require a high density and may be reused.

  15. The relation between herbivore density and relative resource ...

    African Journals Online (AJOL)

    The relation between kudu density and the relative density of habitat patches in each landscape was significant, with exponential models producing more significant statistics than linear models. Regressions of resource density against animal density are useful to understand 'carrying capacity' for wild herbivores, and ...

  16. Cell wall microstructure, pore size distribution and absolute density of hemp shiv

    Science.gov (United States)

    Jiang, Y.; Lawrence, M.; Ansell, M. P.; Hussain, A.

    2018-04-01

    This paper, for the first time, fully characterizes the intrinsic physical parameters of hemp shiv including cell wall microstructure, pore size distribution and absolute density. Scanning electron microscopy revealed microstructural features similar to hardwoods. Confocal microscopy revealed three major layers in the cell wall: middle lamella, primary cell wall and secondary cell wall. Computed tomography improved the visualization of pore shape and pore connectivity in three dimensions. Mercury intrusion porosimetry (MIP) showed that the average accessible porosity was 76.67 ± 2.03% and pore size classes could be distinguished into micropores (3-10 nm) and macropores (0.1-1 µm and 20-80 µm). The absolute density was evaluated by helium pycnometry, MIP and Archimedes' methods. The results show that these methods can lead to misinterpretation of absolute density. The MIP method showed a realistic absolute density (1.45 g cm-3) consistent with the density of the known constituents, including lignin, cellulose and hemi-cellulose. However, helium pycnometry and Archimedes' methods gave falsely low values owing to 10% of the volume being inaccessible pores, which require sample pretreatment in order to be filled by liquid or gas. This indicates that the determination of the cell wall density is strongly dependent on sample geometry and preparation.

  17. Age-Related Changes in Trabecular and Cortical Bone Microstructure

    Directory of Open Access Journals (Sweden)

    Huayue Chen

    2013-01-01

    Full Text Available The elderly population has substantially increased worldwide. Aging is a complex process, and the effects of aging are myriad and insidious, leading to progressive deterioration of various organs, including the skeleton. Age-related bone loss and resultant osteoporosis in the elderly population increase the risk for fractures and morbidity. Osteoporosis is one of the most common conditions associated with aging, and age is an independent risk factor for osteoporotic fractures. With the development of noninvasive imaging techniques such as computed tomography (CT, micro-CT, and high resolution peripheral quantitative CT (HR-pQCT, imaging of the bone architecture provides important information about age-related changes in bone microstructure and estimates of bone strength. In the past two decades, studies of human specimens using imaging techniques have revealed decreased bone strength in older adults compared with younger adults. The present paper addresses recently studied age-related changes in trabecular and cortical bone microstructure based primarily on HR-pQCT and micro-CT. We specifically focus on the three-dimensional microstructure of the vertebrae, femoral neck, and distal radius, which are common osteoporotic fracture sites.

  18. Age-related changes in trabecular and cortical bone microstructure.

    Science.gov (United States)

    Chen, Huayue; Zhou, Xiangrong; Fujita, Hiroshi; Onozuka, Minoru; Kubo, Kin-Ya

    2013-01-01

    The elderly population has substantially increased worldwide. Aging is a complex process, and the effects of aging are myriad and insidious, leading to progressive deterioration of various organs, including the skeleton. Age-related bone loss and resultant osteoporosis in the elderly population increase the risk for fractures and morbidity. Osteoporosis is one of the most common conditions associated with aging, and age is an independent risk factor for osteoporotic fractures. With the development of noninvasive imaging techniques such as computed tomography (CT), micro-CT, and high resolution peripheral quantitative CT (HR-pQCT), imaging of the bone architecture provides important information about age-related changes in bone microstructure and estimates of bone strength. In the past two decades, studies of human specimens using imaging techniques have revealed decreased bone strength in older adults compared with younger adults. The present paper addresses recently studied age-related changes in trabecular and cortical bone microstructure based primarily on HR-pQCT and micro-CT. We specifically focus on the three-dimensional microstructure of the vertebrae, femoral neck, and distal radius, which are common osteoporotic fracture sites.

  19. Effects of UO2 fuel microstructure and density on fuel in-reactor performance

    International Nuclear Information System (INIS)

    Hansson, L.

    1988-02-01

    The volume changes of UO 2 fuel pellets, produced by neutron irradiation, can be characterized by two processes: fission spike induced densification through pore skrinkage and later fission produced induced swelling of UO 2 matrix. In-pile densification is controlled by the initial density and microstructure of the fuel, particularly by the pore size distribution. The extent of swelling depends mainly on the amount of fission products produced, but the fission gas release as well as the swelling may be reduced by increasing the grain size of UO 2 . Fabrication of fuel pellets having certain in-reactor properties requires detailed knowledge of the effects of individual fabrication parameters. The irradiation experience of fuels fabricated by using different conversion and pelletizing methods is extensive. Based on this experience, some general characteristics of stable/well-performing fuel microstructures have been summarized

  20. CO{sub 2} corrosion resistance of carbon steel in relation with microstructure changes

    Energy Technology Data Exchange (ETDEWEB)

    Ochoa, Nathalie, E-mail: nochoa@usb.ve [Departamento de Ciencia de los Materiales, Universidad Simón Bolívar, Aptdo., 89000, Caracas (Venezuela, Bolivarian Republic of); Vega, Carlos [Departamento de Ciencia de los Materiales, Universidad Simón Bolívar, Aptdo., 89000, Caracas (Venezuela, Bolivarian Republic of); Pébère, Nadine; Lacaze, Jacques [Université de Toulouse, CIRIMAT, UPS/INPT/CNRS, ENSIACET, 4 Allée Emile Monso, CS 44362, 31030 Toulouse Cedex 4 (France); Brito, Joaquín L. [Laboratorio de Físico-química de Superficies, Centro de Química, Instituto Venezolano de Investigaciones Cientificas (IVIC), Carretera Panamericana, Km 11, Altos de Pipe, Estado Miranda (Venezuela, Bolivarian Republic of)

    2015-04-15

    The microstructural effects on the corrosion resistance of an API 5L X42 carbon steel in 0.5 M NaCl solution saturated with CO{sub 2} was investigated. Four microstructures were considered: banded (B), normalized (N), quenched and tempered (Q&T), and annealed (A). Electrochemical measurements (polarization curves and electrochemical impedance spectroscopy) were coupled with surface analyses (scanning electron microscope (SEM) and X-ray photoelectron spectroscopy (XPS)) to characterize the formation of the corrosion product layers. Electrochemical results revealed that corrosion resistance increased in the following order: B < N < Q&T < A. From the polarization curves it was shown that specifically, cathodic current densities were affected by microstructural changes. SEM images indicated that ferrite dissolved earlier than cementite and a thin layer of corrosion products was deposited on the steel surface. XPS analyses revealed that this layer was composed of a mixture of iron carbonate and non-dissolved cementite. It was also found that the quantity of FeCO{sub 3} content on the steel surface was greater for Q&T and A microstructures. These results, in agreement with the electrochemical data, indicate that the deposition mechanism of iron carbonate is closely related to the morphology of the non-dissolved cementite, determining the protective properties of the corrosion product layers. - Highlights: • The effect of change in microstructure on CO{sub 2} corrosion resistance was evaluated. • An API 5LX 42 carbon steel was immersed in a 0.5 M NaCl solution saturated with CO{sub 2}. • Banded, normalized, quenched-tempered and annealed microstructures were considered. • Electrochemical measurements were coupled with surface analysis. • Morphology and distribution of undissolved Fe{sub 3}C control corrosion kinetics.

  1. Impact of Weight Loss With Intragastric Balloon on Bone Density and Microstructure in Obese Adults.

    Science.gov (United States)

    Madeira, Eduardo; Madeira, Miguel; Guedes, Erika Paniago; Mafort, Thiago Thomaz; Moreira, Rodrigo Oliveira; de Mendonça, Laura Maria Carvalho; Lima, Inayá Correa Barbosa; Neto, Leonardo Vieira; de Pinho, Paulo Roberto Alves; Lopes, Agnaldo José; Farias, Maria Lucia Fleiuss

    2018-03-21

    The historical concept that obesity protects against bone fractures has been questioned. Weight loss appears to reduce bone mineral density (BMD); however, the results in young adults are inconsistent, and data on the effects of weight loss on bone microstructure are limited. This study aimed to evaluate the impact of weight loss using an intragastric balloon (IGB) on bone density and microstructure. Forty obese patients with metabolic syndrome (mean age 35.1 ± 7.3 yr) used an IGB continuously for 6 mo. Laboratory tests, areal BMD, and body composition measurements via dual-energy X-ray absorptiometry, and volumetric BMD and bone microstructure measurements via high-resolution peripheral quantitative computed tomography were conducted before IGB placement and after IGB removal. The mean weight loss was 11.5%. After 6 mo, there were significant increases in vitamin D and carboxyterminal telopeptide of type 1 collagen levels. After IGB use, areal BMD increased in the spine but decreased in the total femur and the 33% radius. Cortical BMD increased in the distal radius but tended to decrease in the distal tibia. The observed trabecular bone loss in the distal tibia contributed to the decline in the total volumetric BMD at this site. There was a negative correlation between the changes in leptin levels and the measures of trabecular quality in the tibia on high-resolution peripheral quantitative computed tomography. Weight loss may negatively impact bone microstructure in young patients, especially for weight-bearing bones, in which obesity has a more prominent effect. Copyright © 2018 The International Society for Clinical Densitometry. Published by Elsevier Inc. All rights reserved.

  2. Evaluation of microstructure and phase relations in a powder processed Ti-44Al-12Nb alloy

    International Nuclear Information System (INIS)

    Kumar, S.G.; Reddy, R.G.; Wu, J.; Holthus, J.

    1995-01-01

    Titanium aluminides based on the ordered face-centered tetragonal γTiAl phase possess attractive properties, such as low density, high melting point, good elevated temperature strength, modulus retention, and oxidation resistance, making these alloys potential high-temperature structural materials. These alloys can be processed by both ingot metallurgy and powder metallurgy routes. In the present study, three variations of the powder metallurgy route were studied to process a Ti-44Al-12Nb (at.%) alloy: (a) cold pressing followed by reaction sintering (CP process); (b) cold pressing, vacuum hot pressing, and then sintering (HP process); and (c) arc melting, hydride-dehydride process to make the alloy powder, cold isostatic pressing, and then sintering (AM process). Microstructural and phase relations were studied by x-ray diffraction (XRD) analysis, optical microscopy, scanning electron microscopy with an energy-dispersive spectrometer (SEM-EDS), and electron probe microanalysis (EPMA). The phases identified were Ti 3 Al and TiAl; an additional Nb 2 Al phase was observed in the HP sample. The microstructures of CP and HP processed samples are porous and chemically inhomogeneous whereas the AM processed sample revealed fine equiaxed microstructure. This refinement of the microstructure is attributed to the fine, homogeneous powder produced by the hydride-dehydride process and the high compaction pressures

  3. Effects of Processing Parameters on the Density and Microstructure of Pyrolytic Carbon

    International Nuclear Information System (INIS)

    Kim, Weon Ju; Park, Jeong Nam; Park, Jong Hoon; Cho, Moon Sung; Lee, Young Woo; Park, Ji Yeon

    2007-01-01

    Chemical vapor deposition (CVD) of pyrolytic carbon (PyC) and silicon carbide (SiC) has been applied to TRISO-coated fuel particles for high-temperature gas-cooled reactors (HTGR). The porous PyC coating layer, called the buffer layer, attenuates fission recoils and provides void volume for gaseous fission products and carbon monoxide. The inner PyC layer acts as a containment to gaseous products. The outer PyC layer protects the SiC coating layer by inducing a compressive stress and provides chemical compatibility with a graphite matrix in the fuel compact. The PyC layers undergo shrinkage due to neutron irradiation, affecting the design and modeling of fuel particles. Because the dimensional change of PyC depends on the detailed microstructure of PyC, it differs from one fabrication route to another one. This requires a new design of irradiation experiment applicable to spherical objects and leads to an international collaborative work called PYCASSO (PYrocarbon irradiation for Creep And Swelling/Shrinkage of Objects). KAERI proposed four different types of PyC layers coated on ZrO 2 particles, buffer with a density of 1.0 and dense PyCs with densities of 1.7, 1.9 and 2.1 g/cm 3 , for the irradiation experiment. In this study, we fabricated PyC-coated particles with various coating densities for supporting the PYCASSO experiment. We also investigated effects of processing parameters such as temperature, hydrocarbon concentration and gas flow rate on the density and microstructure of the PyC layer

  4. Microstructural characterization and density change of 304 stainless steel reflector blocks after long-term irradiation in EBR-II

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Y., E-mail: yina.huang@materials.ox.ac.uk [University of Wisconsin, Madison, WI 53706 (United States); Wiezorek, J.M.K. [University of Pittsburgh, Pittsburgh, PA 15260 (United States); Garner, F.A. [Radiation Effects Consulting, 2003 Howell Ave., Richland, WA 99354 (United States); Freyer, P.D. [Westinghouse Electric Company LLC, Pittsburgh, PA 15235 (United States); Okita, T. [University of Tokyo, Tokyo (Japan); Sagisaka, M.; Isobe, Y. [Nuclear Fuel Industries, Ltd., Osaka (Japan); Allen, T.R. [University of Wisconsin, Madison, WI 53706 (United States)

    2015-10-15

    While thin reactor structural components such as cladding and ducts do not experience significant gradients in dpa rate, gamma heating rate, temperature or stress, thick components can develop strong local variations in void swelling and irradiation creep in response to gradients in these variables. In this study we conducted microstructural investigations by transmission electron microscopy of two 52 mm thick 304-type stainless steel hex-blocks irradiated for 12 years in the EBR-II reactor with accumulated doses ranging from ∼0.4 to 33 dpa. Spatial variations in the populations of voids, precipitates, Frank loops and dislocation lines have been determined for 304 stainless steel sections exposed to different temperatures, different dpa levels and at different dpa rates, demonstrating the existence of spatial gradients in the resulting void swelling. The microstructural measurements compare very well with complementary density change measurements regarding void swelling gradients in the 304 stainless steel hex-block components. The TEM studies revealed that the original cold-worked-state microstructure of the unirradiated blocks was completely erased by irradiation, replaced by high densities of interstitial Frank loops, voids and carbide precipitates at both the lowest and highest doses. At large dose levels the amount of volumetric void swelling correlated directly with the gamma heating gradient-related temperature increase (e.g. for 28 dpa, ∼2% swelling at 418 °C and ∼2.9% swelling at 448 °C). Under approximately iso-thermal local conditions, volumetric void swelling was found to increase with dose level (e.g. ∼0.2% swelling at 0.4 dpa, ∼0.5% swelling at 4 dpa and ∼2% swelling at 28 dpa). Carbide precipitate formation levels were found to be relatively independent of both dpa level and temperature and induced a measurable densification. Void swelling was dominant at the higher dose levels and caused measurable decreases in density. Void

  5. Microstructural characterization and density change of 304 stainless steel reflector blocks after long-term irradiation in EBR-II

    Science.gov (United States)

    Huang, Y.; Wiezorek, J. M. K.; Garner, F. A.; Freyer, P. D.; Okita, T.; Sagisaka, M.; Isobe, Y.; Allen, T. R.

    2015-10-01

    While thin reactor structural components such as cladding and ducts do not experience significant gradients in dpa rate, gamma heating rate, temperature or stress, thick components can develop strong local variations in void swelling and irradiation creep in response to gradients in these variables. In this study we conducted microstructural investigations by transmission electron microscopy of two 52 mm thick 304-type stainless steel hex-blocks irradiated for 12 years in the EBR-II reactor with accumulated doses ranging from ∼0.4 to 33 dpa. Spatial variations in the populations of voids, precipitates, Frank loops and dislocation lines have been determined for 304 stainless steel sections exposed to different temperatures, different dpa levels and at different dpa rates, demonstrating the existence of spatial gradients in the resulting void swelling. The microstructural measurements compare very well with complementary density change measurements regarding void swelling gradients in the 304 stainless steel hex-block components. The TEM studies revealed that the original cold-worked-state microstructure of the unirradiated blocks was completely erased by irradiation, replaced by high densities of interstitial Frank loops, voids and carbide precipitates at both the lowest and highest doses. At large dose levels the amount of volumetric void swelling correlated directly with the gamma heating gradient-related temperature increase (e.g. for 28 dpa, ∼2% swelling at 418 °C and ∼2.9% swelling at 448 °C). Under approximately iso-thermal local conditions, volumetric void swelling was found to increase with dose level (e.g. ∼0.2% swelling at 0.4 dpa, ∼0.5% swelling at 4 dpa and ∼2% swelling at 28 dpa). Carbide precipitate formation levels were found to be relatively independent of both dpa level and temperature and induced a measurable densification. Void swelling was dominant at the higher dose levels and caused measurable decreases in density. Void swelling

  6. Effects of short-term swimming exercise on bone mineral density, geometry, and microstructural properties in sham and ovariectomized rats

    Directory of Open Access Journals (Sweden)

    Foong Kiew Ooi

    2014-12-01

    Full Text Available Little information exists about the effects of swimming exercise on bone health in ovariectomized animals with estrogen deficiency, which resembles the postmenopausal state and age-related bone loss in humans. This study investigated the effects of swimming exercise on tibia and femur bone mineral density (BMD, geometry, and microstructure in sham and ovariectomized rats. Forty 3-month-old female rats were divided into four groups: sham operated-sedentary control (Sham-control, sham operated with swimming exercise group (Sham-Swim, ovariectomy-sedentary control (OVx-control, and ovariectomy and swimming exercise (OVx-Swim groups. Swimming sessions were performed by the rats 90 minutes/day for 5 days/week for a total of 8 weeks. At the end of the study, tibial and femoral proximal volumetric total BMD, midshaft cortical volumetric BMD, cross-sectional area, and cross-sectional moment of inertia (MOI, and bone microstructural properties were measured for comparison. Data were analyzed using one-way analysis of variance (ANOVA. The Sham-Swim group exhibited significantly (p < 0.05; one-way ANOVA greater values in bone geometry parameters, that is, tibial midshaft cortical area and MOI compared to the Sham-control group. However, no significant differences were observed in these parameters between the Ovx-Swim and Ovx-control groups. There were no significant differences in femoral BMD between the Sham-Swim and Sham-control groups. Nevertheless, the Ovx-Swim group elicited significantly (p < 0.05; one-way ANOVA higher femoral proximal total BMD and improved bone microstructure compared to the Ovx-Sham group. In conclusion, the positive effects of swimming on bone properties in the ovariectomized rats in the present study may suggest that swimming as a non- or low-weight-bearing exercise may be beneficial for enhancing bone health in the postmenopausal population.

  7. Age-related changes in vertebral and iliac crest 3D bone microstructure--differences and similarities.

    Science.gov (United States)

    Thomsen, J S; Jensen, M V; Niklassen, A S; Ebbesen, E N; Brüel, A

    2015-01-01

    Age-related changes of vertebra and iliac crest 3D microstructure were investigated, and we showed that they were in general similar. The 95th percentile of vertebral trabecular thickness distribution increased with age for women. Surprisingly, vertebral and iliac crest bone microstructure was only weakly correlated (r = 0.38 to 0.75), despite the overall similar age-related changes. The purposes of the study were to determine the age-related changes in iliac and vertebral bone microstructure for women and men over a large age range and to investigate the relationship between the bone microstructure at these skeletal sites. Matched sets of transiliac crest bone biopsies and lumbar vertebral body (L2) specimens from 41 women (19-96 years) and 39 men (23-95 years) were micro-computed tomography (μCT) scanned, and the 3D microstructure was quantified. For both women and men, bone volume per total volume (BV/TV), connectivity density (CD), and trabecular number (Tb.N) decreased significantly, while structure model index (SMI) and trabecular separation (Tb.Sp) increased significantly with age at either skeletal site. Vertebral trabecular thickness (Tb.Th) was independent of age for both women and men, while iliac Tb.Th decreased significantly with age for men, but not for women. In general, the vertebral and iliac age-related changes were similar. The 95th percentile of the Tb.Th distribution increased significantly with age for women but was independent of age for men at the vertebral body, while it was independent of age for either sex at the iliac crest. The Tb.Th probability density functions at the two skeletal sites became significantly more similar with age for women, but not for men. The microstructural parameters at the iliac crest and the vertebral bodies were only moderately correlated from r = 0.38 for SMI in women to r = 0.75 for Tb.Sp in men. Age-related changes in vertebral and iliac bone microstructure were in general similar. The iliac

  8. Comparison of immersion density and improved microstructural characterization methods for measuring swelling in small irradiated disk specimens

    International Nuclear Information System (INIS)

    Sawai, T.; Suzuki, M.; Hishinuma, A.; Maziasz, P.J.

    1992-01-01

    The procedure of obtaining microstructural data from reactor-irradiated specimens has been carefully checked for accuracy by comparison of swelling data obtained from transmission electron microscopy (TEM) observations of cavities with density-change data measured using the Precision Densitometer at Oak Ridge National Laboratory (ORNL). Comparison of data measured by both methods on duplicate or, in some cases, on the same specimen has shown some appreciable discrepancies for US/Japan collaborative experiments irradiated in the High Flux Isotope Reactor (HFIR). The contamination spot separation (CSS) method was used in the past to determine the thickness of a TEM foil. Recent work has revealed an appreciable error in this method that can result in an overestimation of the foil thickness. This error causes lower swelling values to be measured by TEM microstructural observation relative to the Precision Densitometer. An improved method is proposed for determining the foil thickness by the CSS method, which includes a correction for the systematic overestimation of foil thickness. (orig.)

  9. Characteristic of Polymer-Impregnated Cement Mortar: Composites: Bulk Density and Microstructure

    International Nuclear Information System (INIS)

    Younes, M.M.; Abo-El-Enein, S.A.; El-Saft, M.M.; Sadek, M.A.; Zohdy, K.M.

    2010-01-01

    The effect of radiation initiated polymerization of some monomers on the physical properties of polymer-incorporated mortar was studied. The monomers used were: castor oil (C.O.), 4, 4'-diphenylmethane diisocyanate (MDI) and methyl methacrylate (MMA). Polymerization was carried out by subjecting the monomer-impregnated mortar specimens to different doses of gamma radiation. Where polyurethane (pu) and polyurethane -methyl methacrylate copolymers were formed within the pore system. The influence of polymer impregnation on the various physico-mechanical characteristics of the resulting composites was studied with respect to bulk density and polymer loading. Scanning electron microscopy (SEM) was employed to study the micro-structural characteristics of the neat hardened Ordinary Portland Cement (OPC) mortar pastes and their polymer-impregnated composites

  10. Angle-adjustable density field formulation for the modeling of crystalline microstructure

    Science.gov (United States)

    Wang, Zi-Le; Liu, Zhirong; Huang, Zhi-Feng

    2018-05-01

    A continuum density field formulation with particle-scale resolution is constructed to simultaneously incorporate the orientation dependence of interparticle interactions and the rotational invariance of the system, a fundamental but challenging issue in modeling the structure and dynamics of a broad range of material systems across variable scales. This generalized phase field crystal-type approach is based upon the complete expansion of particle direct correlation functions and the concept of isotropic tensors. Through applications to the modeling of various two- and three-dimensional crystalline structures, our study demonstrates the capability of bond-angle control in this continuum field theory and its effects on the emergence of ordered phases, and provides a systematic way of performing tunable angle analyses for crystalline microstructures.

  11. Carbonation-Related Microstructural Changesin Long-Term Durability Concrete

    Directory of Open Access Journals (Sweden)

    Cláudio A. Rigo da Silva

    2002-09-01

    Full Text Available This paper discusses the effects of carbonation on the microstructure of Portland cement concrete for long-term durability applications. A class C40 concrete (characteristic compression strength between 40 MPa and 44 MPa on the 28th day, according to Brazilian standard NBR 8953 was chosen for the experimental study of the carbonation effects, from which test samples were molded for accelerated test under a 100%-CO2 atmosphere after physical and mechanical characterization. It was observed that carbonation provoked a reduction of 5% to 12% of the concrete open porosity accessible to water. Flexural strength values obtained after the carbonation tests revealed a decrease of 12% and 25% in relation to the values obtained before tests on the 28th and 91st days, respectively.

  12. Influence of current density on microstructure and properties of electrodeposited nickel-alumina composite coatings

    International Nuclear Information System (INIS)

    Góral, Anna; Nowak, Marek; Berent, Katarzyna; Kania, Bogusz

    2014-01-01

    Highlights: • Current density of the electrodeposition affects the incorporation of Al 2 O 3 in Ni matrix. • Ni/Al 2 O 3 composite coatings exhibit changes in crystallographic texture. • The pitting corrosion effects were observed in Ni/Al 2 O 3 coatings. • Residual stresses were decreased with increasing current density and coating thickness. - Abstract: Electrodeposition process is a very promising method for producing metal matrix composites reinforced with ceramic particles. In this method insoluble particles suspended in an electrolytic bath are embedded in a growing metal layer. This paper is focused on the investigations of the nickel matrix nanocomposite coatings with hard α-Al 2 O 3 nano-particles, electrochemically deposited from modified Watts-type baths on steel substrates. The influence of various current densities on the microstructure, residual stresses, texture, hardness and corrosion resistance of the deposited nickel/alumina coatings was investigated. The surface morphology, cross sections of the coatings and distribution of the ceramic particles in the metal matrix were examined by scanning electron microscopy. The phase composition, residual stresses and preferred grain orientation of the coatings were characterized using X-ray diffraction techniques. The coating morphology revealed that α-Al 2 O 3 particles show a distinct tendency to form agglomerates, approximately uniformly distributed into the nickel matrix

  13. Engineering related neutron diffraction measurements probing strains, texture and microstructure

    Energy Technology Data Exchange (ETDEWEB)

    Clausen, Bjorn [Los Alamos National Laboratory; Brown, Donald W [Los Alamos National Laboratory; Tome, Carlos N [Los Alamos National Laboratory; Balogh, Levente [Los Alamos National Laboratory; Vogel, Sven C [Los Alamos National Laboratory

    2010-01-01

    Neutron diffraction has been used for engineering applications for nearly three decades. The basis of the technique is powder diffraction following Bragg's Law. From the measured diffraction patterns information about internal, or residual, strain can be deduced from the peak positions, texture information can be extracted from the peak intensities, and finally the peak widths can provide information about the microstructure, e.g. dislocation densities and grain sizes. The strains are measured directly from changes in lattice parameters, however, in many cases it is non-trivial to determine macroscopic values of stress or strain from the measured data. The effects of intergranular strains must be considered, and combining the neutron diffraction measurements with polycrystal deformation modeling has proven invaluable in determining the overall stress and strain values of interest in designing and dimensioning engineering components. Furthelmore, the combined use of measurements and modeling has provided a tool for elucidating basic material properties, such as critical resolved shear stresses for the active deformation modes and their evolution as a function of applied deformation.

  14. Local relative density modulates failure and strength in vertically aligned carbon nanotubes.

    Science.gov (United States)

    Pathak, Siddhartha; Mohan, Nisha; Decolvenaere, Elizabeth; Needleman, Alan; Bedewy, Mostafa; Hart, A John; Greer, Julia R

    2013-10-22

    Micromechanical experiments, image analysis, and theoretical modeling revealed that local failure events and compressive stresses of vertically aligned carbon nanotubes (VACNTs) were uniquely linked to relative density gradients. Edge detection analysis of systematically obtained scanning electron micrographs was used to quantify a microstructural figure-of-merit related to relative local density along VACNT heights. Sequential bottom-to-top buckling and hardening in stress-strain response were observed in samples with smaller relative density at the bottom. When density gradient was insubstantial or reversed, bottom regions always buckled last, and a flat stress plateau was obtained. These findings were consistent with predictions of a 2D material model based on a viscoplastic solid with plastic non-normality and a hardening-softening-hardening plastic flow relation. The hardening slope in compression generated by the model was directly related to the stiffness gradient along the sample height, and hence to the local relative density. These results demonstrate that a microstructural figure-of-merit, the effective relative density, can be used to quantify and predict the mechanical response.

  15. Microstructure-electrical properties relation of zirconia based ceramic composites

    International Nuclear Information System (INIS)

    Fonseca, Fabio Coral

    2001-01-01

    The electrical properties of zirconia based ceramic composites were studied by impedance spectroscopy. Three materials were prepared with different relative compositions of the conducting and insulating phases: (ZrO 2 :8 mol% Y 2 ) 3 ) + MgO, (ZrO 2 :8 mol% Y 2 O 3 ) + Y 2 O 3 and ZrO 2 + 8 mol% Y 2 O 3 . All specimens were analyzed by X-ray diffraction and scanning electron microscopy for microstructural characterization and for correlation of microstructural aspects with electrical properties. For (ZrO 2 :8 mol% Y 2 O 3 ) + MgO the main results show that the dependence of the different (microstructural constituents) contributions to the electrical resistivity on the magnesia content follows two stages: one below and another above the solubility limit of magnesia in Yttria-stabilized zirconia. The same dependence is found for the lattice parameter determined by X-ray diffraction measurements. The impedance diagrams of the composites have been resolved allowing the identification of contributions due to the presence of each microstructural constituent in both stages. Magnesia as a second phase is found to inhibit grain growth in Yttria-stabilized zirconia and the solubility limit for magnesia in the zirconia matrix is around 10 mol%. For (ZrO 2 :8 mol% Y 2 O 3 ) + Y 2 O 3 the main results show that: Yttria is present as a second phase for 1350 deg C /0.1 h sintering; the addition of 2 mol% of Yttria does not modify significantly the electrical properties; the solubility limit for Yttria is around 2 mol% according to electrical measurements. Similarly to magnesia, Yttria inhibits grain growth on Yttria-stabilized zirconia. The general effective medium theory was used to analyze the percolation of the insulating phase; the percolation threshold is different if one considers separately the total, bulk and grain boundary contributions to the electrical conductivity: 32.0, 38.5 and 27.8 vol% for total, intra and intergranular contributions, respectively. The increase of

  16. Recrystallization - Fundamental aspects and relations to deformation microstructure

    International Nuclear Information System (INIS)

    Hansen, N.; Huang, X.; Juul Jensen, D.; Lauridsen, E.M.; Leffers, T.; Pantleon, W.; Sabin, T.J.; Wert, J.A.

    2000-01-01

    This Symposium, and hence this proceedings volume, is concerned with the mechanisms that control recrystallization of deformed metals and alloys. Central themes are the fundamental microstructural, orientational, and kinetic aspects of the recrystallization process; especially as they relate to the nature of the deformed state, to nucleation and growth of recrystallizing grains, and to models based on experimental observations. In recent years, significant progress has been made using a plethora of advanced techniques to characterize the morphology and local orientations in deformed metals and alloys. Thus, a key topic of the Symposium is enhanced insight into the characteristics of the deformation substructure, and into modification of the substructure by recovery, which is essential for understanding fundamental recrystallization mechanisms. Microstructures in highly strained materials will be a topic of special interest. Elucidation of the deformation substructure, and thus the local distribution of stored energy, sets the stage for progress in understanding nucleation of recrystallizing grains. It also provides a basis for new insights into the growth of nuclei, in particular concerning the means by which the deformation substructure is absorbed by and becomes incorporated into the recrystallization interface. Aspects of recrystallization of relevance to this symposium span the range from experimental and model exploration of fundamental mechanisms to methods that link scientific understanding to industrial practice. Models developed by considering the physical mechanisms elucidated by experimental studies will be addressed, as will models that enable industrial exploitation of the fundamental knowledge. Altogether, one of the significant aims of the symposium is to enhance the exploitation of the expanding knowledge of fundamental recrystallization mechanisms in industrial practice (au)

  17. Microstructure of III-N semiconductors related to their applications in optoelectronics

    Science.gov (United States)

    Leszczynski, M.; Czernetzki, R.; Sarzynski, M.; Krysko, M.; Targowski, G.; Prystawko, P.; Bockowski, M.; Grzegory, I.; Suski, T.; Domagala, J.; Porowski, S.

    2005-03-01

    There has been more than a decade since Shuji Nakamura from Japanese company Nichia constructed the first blue LED based on structure of (AlGaIn)N semiconductor and eight years since he made the first blue laser diode (LD). This work gives a survey on the current technological status with green/blue/violet/UV optoelectronics based on III-N semiconductors in relation with their microstructure. The following devices are presented: i) Low-power green and blue LEDs, ii) High-power LEDs targeting solid-state white lighting, iii) Low-power violet LDs for high definition DVD market, iv) High-power violet LDs, v) UV LEDs. The discussion will be focused on three main technological problems related to the microstructure of (AlGaIn)N layers in emitters based on III-N semiconductors: i) high density of dislocations in epitaxial layers of GaN on foreign substrates (sapphire, SiC, GaAs), ii), presence of strains, iii) atom segregation in ternary and quaternary compounds.

  18. Critical current density and microstructure of YBa2Cu3O7-x films as a function of film thickness

    International Nuclear Information System (INIS)

    Mogro-Campero, A.; Turner, L.G.; Hall, E.L.; Lewis, N.

    1990-01-01

    Thin films of nominal composition YBa 2 Cu 3 O 7-x (YBCO) were produced on (100) SrTiO 3 substrates by coevaporation and furnace annealing. Film thicknesses in the range of 0.2 to 2.4 μm were analyzed. Microstructural investigations by cross sectional transmission electron microscopy (TEM) reveal a continuous layer of about 0.4 μm thickness adjacent to the substrate with c-axis normal to the substrate plane. In thicker films the remaining top portion has the c-axis in the film plane. The critical current density (J c ) at 77 K decreases with increasing thickness in the thickness range exceeding 0.4 μm, qualitatively consistent with the microstructural observation, but quantitatively inconsistent with a simple model based on the microstructural data

  19. Study of microstructure and fracture properties of blunt notched and sharp cracked high density polyethylene specimens.

    Science.gov (United States)

    Pan, Huanyu; Devasahayam, Sheila; Bandyopadhyay, Sri

    2017-07-21

    This paper examines the effect of a broad range of crosshead speed (0.05 to 100 mm/min) and a small range of temperature (25 °C and 45 °C) on the failure behaviour of high density polyethylene (HDPE) specimens containing a) standard size blunt notch and b) standard size blunt notch plus small sharp crack - all tested in air. It was observed that the yield stress properties showed linear increase with the natural logarithm of strain rate. The stress intensity factors under blunt notch and sharp crack conditions also increased linearly with natural logarithm of the crosshead speed. The results indicate that in the practical temperature range of 25 °C and 45 °C under normal atmosphere and increasing strain rates, HDPE specimens with both blunt notches and sharp cracks possess superior fracture properties. SEM microstructure studies of fracture surfaces showed craze initiation mechanisms at lower strain rate, whilst at higher strain rates there is evidence of dimple patterns absorbing the strain energy and creating plastic deformation. The stress intensity factor and the yield strength were higher at 25 °C compared to those at 45 °C.

  20. Encapsulation of low density plastic foam materials for the fast ignition realization experiment (FIREX). Control of microstructure and density

    International Nuclear Information System (INIS)

    Nagai, Keiji; Yang, H.; Iwamoto, A.

    2008-10-01

    Development of foam capsule fabrication for cryogenically cooled fuel targets is overviewed in the present paper. The fabrication development was initiated as a part of the Fast Ignition Realization Experiment (FIREX) Project at the ILE, Osaka University in the way of bilateral collaboration between Osaka University and National Institute for Fusion Science (NIFS). A foam cryogenic target was designed where low-density foam shells with a conical light guide will be cooled down to the cryogenic temperature and will be fueled through a narrow pipe. The required diameter and thickness of the capsule are 500 μm and 20 μm, respectively. The material should be low-density plastics foam. We have prepared such capsules using 1) mixtureing a new material of (phloroglucinolcarboxylic acid)/formalin (PF) linear polymer to control kinematic viscosity of the precursor, 2) phase-transfer-catalyzed gelation process to keep density matching of three phases of the emulsion. 3) non-volatile silicone oil as outer oil of emulsion in order to prevent hazard halogenated hydrocarbon and flammable mineral oil. The obtained foam capsule had fine structure of 180 nm (outer surface) to 220 nm (inner surface) and uniform thickness reaching to resolution limit of optical analysis (∼0.5 μm). A small hole was made before the solvent exchange and the drying process to prevent distortion due to volume changes. The density of dried foam was 0.29 g/cm 3 . After attaching the petawatt laser guiding cone and fueling glass tube, poly([2,2]paracyclophane) was coated on the foam surface and supplied for a fueling test of cryogenic hydrogen. Generally, lower density is from larger pore, then precise control of thickness and its encapsulation becomes more difficult. We have clarified the relation between pore size and preparation conditions using several precursor materials, and revealed how to control pore size of low density foams, where the solvent affinity for the polymer chain plays fundamental

  1. Improvement in current density of nano- and micro-structured Si solar cells by cost-effective elastomeric stamp process

    Science.gov (United States)

    Jeon, Kiseok; Jee, Hongsub; Lim, Sangwoo; Park, Min Joon; Jeong, Chaehwan

    2018-03-01

    Effective incident light should be controlled for improving the current density of solar cells by employing nano- and micro-structures on silicon surface. The elastomeric stamp process, which is more cost effective and simpler than conventional photolithography, was proposed for the fabrication of nano- and micro-structures. Polydimethylsiloxane (PDMS) was poured on a mother pattern with a diameter of 6 μm and a spacing of 2 μm; then, curing was performed to create a PDMS mold. The regular micropattern was stamped on a low-viscosity resin-coated silicon surface, followed by the simple reactive ion etching process. Nano-structures were formed using the Ag-based electroless etching process. As etching time was increased to 6 min, reflectance decreased to 4.53% and current density improved from 22.35 to 34.72 mA/cm2.

  2. Microstructure and Properties of Ni and Ni/Al2O3 Coatings Electrodeposited at Various Current Densities

    Directory of Open Access Journals (Sweden)

    Góral A.

    2016-03-01

    Full Text Available The study presents investigations of an influence of various direct current densities on microstructure, residual stresses, texture, microhardness and corrosion resistance of the nickel coatings electrodeposited from modified Watt’s baths. The properties of obtained coatings were compared to the nano-crystalline composite Ni/Al2O3 coatings prepared under the same plating conditions. The similarities and differences of the obtained coatings microstructures visible on both their surfaces and cross sections and determined properties were presented. The differences in the growth character of the Ni matrix and in the microstructural properties were observed. All electrodeposited Ni and Ni/Al2O3 coatings were compact and well adhering to the steel substrates. The thickness and the microhardness of the Ni and Ni/Al2O3 deposits increased significantly with the current density in the range 2 - 6 A/dm2. Residual stresses are tensile and they reduced as the current density increased. The composite coatings revealed better protection from the corrosion of steel substrate than pure nickel in solution 1 M NaCl.

  3. Towards Quantification of Relations Between Electrode Polarisation and Microstructure

    DEFF Research Database (Denmark)

    Ramos, Tania; Hjelm, Johan; Mogensen, Mogens Bjerg

    2011-01-01

    The total cell resistances of three Riso DTU solid oxide fuel cells (SOFCs) were broken down into individual contributions, by the combined use of electrochemical impedance spectroscopy (EIS), and complex non-linear least squares fitting (CNLS). Information on the number of contributing processes....... The proposed electrochemical analysis correlated well with the exhibited microstructural features of the cells, which were produced with different compositions and/or production parameters. (C) 2011 The Electrochemical Society. [DOI: 10.1149/1.3587113] All rights reserved....

  4. Qualitative relations between the kinetics of sintering in hydrogen and the observed microstructures of uranium dioxide

    International Nuclear Information System (INIS)

    Francois, B.; Delmas, R.; Caillat, F.; Lacombe, P.

    1975-01-01

    The microscopic study of uranium dioxide sintered in hydrogen, together with density measurements, shows on the one hand that the large scale appearance of pores trapped at the grain boundaries in the course of sintering has the effect of practically stopping densification, and on the other hand that this particular microstructure is stable over a wide range of time and temperature. (author)

  5. Prior ankle fractures in postmenopausal women are associated with low areal bone mineral density and bone microstructure alterations.

    Science.gov (United States)

    Biver, E; Durosier, C; Chevalley, T; Herrmann, F R; Ferrari, S; Rizzoli, R

    2015-08-01

    In a cross-sectional analysis in postmenopausal women, prior ankle fractures were associated with lower areal bone mineral density (BMD) and trabecular bone alterations compared to no fracture history. Compared to women with forearm fractures, microstructure alterations were of lower magnitude. These data suggest that ankle fractures are another manifestation of bone fragility. Whether ankle fractures represent fragility fractures associated with low areal bone mineral density (aBMD) and volumetric bone mineral density (vBMD) and/or bone microstructure alterations remains unclear, in contrast to the well-recognised association between forearm fractures and osteoporosis. The objective of this study was to investigate aBMD, vBMD and bone microstructure in postmenopausal women with prior ankle fracture in adulthood, compared with women without prior fracture or with women with prior forearm fractures, considered as typically of osteoporotic origin. In a cross-sectional analysis in the Geneva Retirees Cohort study, 63 women with ankle fracture and 59 with forearm fracture were compared to 433 women without fracture (mean age, 65 ± 1 years). aBMD was measured by dual-energy X-ray absorptiometry; distal radius and tibia vBMD and bone microstructure were measured by high-resolution peripheral quantitative computed tomography. Compared with women without fracture, those with ankle fractures had lower aBMD, radius vBMD (-7.9%), trabecular density (-10.7%), number (-7.3%) and thickness (-4.6%) and higher trabecular spacing (+14.5%) (P ankle fractures were 2.2 and 1.6, respectively, vs 2.2 and 2.7 for forearm fracture, respectively (P ≤ 0.001 for all). Compared to women with forearm fractures, those with ankle fractures had similar spine and hip aBMD, but microstructure alterations of lower magnitude. Women with ankle fractures have lower aBMD and vBMD and trabecular bone alterations, suggesting that ankle fractures are another manifestation of bone fragility.

  6. Effect of etching current density on microstructure and NH3-sensing properties of porous silicon with intermediate-sized pores

    International Nuclear Information System (INIS)

    Li, Mingda; Hu, Ming; Zeng, Peng; Ma, Shuangyun; Yan, Wenjun; Qin, Yuxiang

    2013-01-01

    In this work, porous silicon with intermediate-sized pores (intermediate–PS) was prepared by using galvanostatic electrochemical etching method and the effect toward sensing response characteristics of NH 3 gas was also studied. The morphology and surface chemical bonds of intermediate–PS were characterized by using field emission scanning electron microscope (FESEM) and Fourier transform infrared spectroscopy (FTIR), respectively. The results showed the intermediate–PS microstructure can be significantly modulated by the etching current density. Moreover, the freshly prepared intermediate–PS surface could achieve reliable passivation after storage in ethanol. Furthermore, the gas-sensing measurements of the intermediate–PS sensors were carried out versus different concentrations of NH 3 . The PS sensor exhibited good NH 3 -sensing performances at room temperature owing to its unique microstructure features, including large specific surface area and highly ordered pore channels. In addition, the conceivable pore formation mechanism as well as gas sensing mechanism was also discussed

  7. The density-salinity relation of standard seawater

    Science.gov (United States)

    Schmidt, Hannes; Seitz, Steffen; Hassel, Egon; Wolf, Henning

    2018-01-01

    The determination of salinity by means of electrical conductivity relies on stable salt proportions in the North Atlantic Ocean, because standard seawater, which is required for salinometer calibration, is produced from water of the North Atlantic. To verify the long-term stability of the standard seawater composition, it was proposed to perform measurements of the standard seawater density. Since the density is sensitive to all salt components, a density measurement can detect any change in the composition. A conversion of the density values to salinity can be performed by means of a density-salinity relation. To use such a relation with a target uncertainty in salinity comparable to that in salinity obtained from conductivity measurements, a density measurement with an uncertainty of 2 g m-3 is mandatory. We present a new density-salinity relation based on such accurate density measurements. The substitution measurement method used is described and density corrections for uniform isotopic and chemical compositions are reported. The comparison of densities calculated using the new relation with those calculated using the present reference equations of state TEOS-10 suggests that the density accuracy of TEOS-10 (as well as that of EOS-80) has been overestimated, as the accuracy of some of its underlying density measurements had been overestimated. The new density-salinity relation may be used to verify the stable composition of standard seawater by means of routine density measurements.

  8. Comparative Evaluations and Microstructure: Mechanical Property Relations of Sintered Silicon Carbide Consolidated by Various Techniques

    Science.gov (United States)

    Barick, Prasenjit; Chatterjee, Arya; Majumdar, Bhaskar; Saha, Bhaskar Prasad; Mitra, Rahul

    2018-04-01

    A comparative evaluation between pressureless or self-sintered silicon carbide (SSiC), hot-pressed silicon carbide (HP-SiC), and spark plasma-sintered silicon carbide (SPS-SiC) has been carried out with emphasis on examination of their microstructures and mechanical properties. The effect of sample dimensions on density and properties of SPS-SiC has been also examined. Elastic modulus, flexural strength, and fracture toughness measured by indentation or testing of single-edge notched beam specimens have been found to follow the following trend, HP-SiC > SSiC > SPS-SiC. The SPS-SiC samples have shown size-dependent densification and mechanical properties, with the smaller sample exhibiting superior properties. The mechanical properties of sintered SiC samples appear to be influenced by relative density, grain size, and morphology, as well as the existence of intergranular glassy phase. Studies of fracture surface morphologies have revealed the mechanism of failure to be transgranular in SSiC or HP-SiC, and intergranular in case of SPS-SiC, indicating the dominating influence of grain size and α-SiC formation with high aspect ratio.

  9. Relating microstructure, sensory and instrumental texture of processed oat

    Directory of Open Access Journals (Sweden)

    M. SALMENKALLIO-MARTTILA

    2008-12-01

    Full Text Available This study is a part of a larger project aiming to produce new, healthy, and tasty food ingredients from oat. Germination and different heating processes can be used to improve the texture and flavour of cereals. In this study effects of germination and wet and dry heating on the microstructure, instrumental structure and sensory properties of two oat varieties were assessed. The microstructure of native, germinated, autoclaved and extruded grains of the hulled cv. Veli and hull-less cv. Lisbeth was examined by light microscopy, the texture was measured by determining the milling energy and hardness of the grains and sensory characteristics were evaluated with descriptive sensory profile analysis. In cv. Veli the cells of the starchy endosperm were smaller than in cv. Lisbeth and ß-glucan was concentrated in the subaleurone layer. In cv. Lisbeth ß-glucan was evenly distributed in the starchy endosperm. The grains of cv. Lisbeth were more extensively modified in the germination process than the grains of cv. Veli, otherwise the effects of processing on the grains of the two cultivars were similar. Germination caused cell wall degradation, autoclaving and extrusion cooking caused starch gelatinization. Autoclaving resulted in the hardest perceived texture in oat. Gelatinization of starch appeared to contribute more to the hardness of oat groats than the cell wall structure. Of the instrumental methods used in this study the milling energy measurement appeared to be the most useful method for the analysis of the effects of processing on grain structure.;

  10. 3-D image-based numerical computations of snow permeability: links to specific surface area, density, and microstructural anisotropy

    Directory of Open Access Journals (Sweden)

    N. Calonne

    2012-09-01

    Full Text Available We used three-dimensional (3-D images of snow microstructure to carry out numerical estimations of the full tensor of the intrinsic permeability of snow (K. This study was performed on 35 snow samples, spanning a wide range of seasonal snow types. For several snow samples, a significant anisotropy of permeability was detected and is consistent with that observed for the effective thermal conductivity obtained from the same samples. The anisotropy coefficient, defined as the ratio of the vertical over the horizontal components of K, ranges from 0.74 for a sample of decomposing precipitation particles collected in the field to 1.66 for a depth hoar specimen. Because the permeability is related to a characteristic length, we introduced a dimensionless tensor K*=K/res2, where the equivalent sphere radius of ice grains (res is computed from the specific surface area of snow (SSA and the ice densityi as follows: res=3/(SSA×ρi. We define K and K* as the average of the diagonal components of K and K*, respectively. The 35 values of K* were fitted to snow densitys and provide the following regression: K = (3.0 ± 0.3 res2 exp((−0.0130 ± 0.0003ρs. We noted that the anisotropy of permeability does not affect significantly the proposed equation. This regression curve was applied to several independent datasets from the literature and compared to other existing regression curves or analytical models. The results show that it is probably the best currently available simple relationship linking the average value of permeability, K, to snow density and specific surface area.

  11. Effect of electrodeposition current density on the microstructure and the degradation of electroformed iron for degradable stents

    Energy Technology Data Exchange (ETDEWEB)

    Moravej, Maryam [Laboratory for Biomaterials and Bioengineering, Department of Mining, Metallurgy and Materials Engineering and University Hospital Research Center, Universite Laval, Quebec City, Que. G1V 0A6 (Canada); Department of Mining, Metallurgy and Materials Engineering, Pavillon Adrien-Pouliot, 1065 avenue de la Medecine, Local 1745-E, Universite Laval, Quebec City, Que. G1V 0A6 (Canada); Amira, Sofiene [Aluminium Technology Centre, Industrial Materials Institute, National Research Council Canada, 501, boul. de l' Universite Est, Saguenay, Que. G7H 8C3 (Canada); Prima, Frederic [Laboratory for Physical Metallurgy, Ecole Nationale Superieure de Chimie de Paris, Universite Pierre et Marie Curie, Paris 6 (France); Rahem, Ahmed [Aluminium Technology Centre, Industrial Materials Institute, National Research Council Canada, 501, boul. de l' Universite Est, Saguenay, Que. G7H 8C3 (Canada); Fiset, Michel [Department of Mining, Metallurgy and Materials Engineering, Pavillon Adrien-Pouliot, 1065 avenue de la Medecine, Local 1745-E, Universite Laval, Quebec City, Que. G1V 0A6 (Canada); and others

    2011-12-15

    Pure iron has become one of the most interesting candidate materials for degradable metallic stents due to its high mechanical properties and moderate degradation. In this work we studied the effect of electrodeposition current density on microstructure and degradation of pure iron films electrodeposited on Ti alloy substrate for degradable metallic stent application. Iron sheets were produced by electrodeposition using four different current densities 1, 2, 5 and 10 A dm{sup -2}. The films were then studied by SEM (scanning electron microscope) and EBSD (electron backscatter diffraction) to observe the surface morphology, grain size and orientation. Potentiodynamic polarization and static immersion tests were used to determine the corrosion rate and to study the degradation behavior of iron films, respectively. The current density was found to significantly influence the texture, the grain size and the grain shape of the electrodeposited iron. At current densities of 1, 5 and 10 A dm{sup -2}, weak textures corresponding to Left-Pointing-Angle-Bracket 1 0 1 Right-Pointing-Angle-Bracket , Left-Pointing-Angle-Bracket 1 1 1 Right-Pointing-Angle-Bracket and Left-Pointing-Angle-Bracket 1 1 2 Right-Pointing-Angle-Bracket in the normal (electrodeposition) direction were obtained, respectively. At these current densities, average grain sizes smaller than 3 {mu}m were also obtained. However, at 2 A dm{sup -2}, a strong Left-Pointing-Angle-Bracket 1 1 1 Right-Pointing-Angle-Bracket //ND texture with density of 7.4 MUD was obtained with larger average grain size of 4.4 {mu}m. The microstructure of iron samples changed after annealing at 550 Degree-Sign C because of the induced recrystallization. Different corrosion rates were obtained from potentiodynamic polarization curves of iron films deposited at different current densities because of their microstructures. Fe-2 showed the lowest corrosion rate due to its larger grains size and its texture. The corrosion rates of all

  12. Evolution of microstructure and mechanical properties during thermomechanical processing of a low-density multiphase steel for automotive application

    International Nuclear Information System (INIS)

    Rana, R.; Liu, C.; Ray, R.K.

    2014-01-01

    The evolution of the microstructure and mechanical properties in a low-density, low-alloy steel containing 6.57Al–3.34Mn–0.18C (wt.%) has been investigated as a function of processing. The steel was designed to have a duplex microstructure with ferrite as the major phase and austenite as the minor phase within the temperature range 800–1350 °C. The steel was processed to sheet form, which was thermomechanically treated and characterised by a variety of techniques such as optical metallography, scanning electron microscopy, electron backscatter diffraction, electron probe microanalysis, X-ray diffraction, transmission electron microscopy, tensile testing and density and elastic modulus measurements. The amount of austenite was found to decrease with an increase in the annealing temperature. While C and Mn partitioned into the austenite phase, Al partitioned into the ferrite. The tensile elongation increased with an increase in the amount of austenite in the microstructure. However, the austenite showed only a small transformation induced plasticity effect during tensile deformation due to its high stability. After annealing, mostly κ-carbide precipitates with a (Fe + Mn)/Al ratio of 3.6 appeared in the ferrite matrix, along with some cementite and complex carbides. These precipitates became coarser (330 nm) during a short time overageing treatment at 400 °C, causing a significant increase in elongation. The κ-carbides were found to have a close to Nishiyama–Wasserman type orientation relationship with the ferrite matrix. Although the Young’s modulus of the steel dropped due to the large amount of Al added, the reduced density was found to be beneficial for automotive applications, overriding the effect of a drop in Young’s modulus

  13. Transport critical current density and microstructure in extruded YBa2Cu3O7-x wires processed by zone melting

    International Nuclear Information System (INIS)

    Shi, D.; Krishnan, H.; Hong, J.M.; Miller, D.; McGinn, P.J.; Chen, W.H.; Xu, M.; Chen, J.G.; Fang, M.M.; Welp, U.; Lanagan, M.T.; Goretta, K.C.; Dusek, J.T.; Picciolo, J.J.; Balachandran, U.

    1990-01-01

    YBa 2 Cu 3 O 7-x compounds were extruded into long wires with the diameter of 1 mm after sintering. The sintered wires were subsequently zone melted to develop a highly textured microstructure. Magnetization experiments at 77 K indicated a J c value of 1x10 5 A/cm 2 at 1 T. Transport measurements at 77 K showed a greatly enhanced field dependence of the critical current density. Transmission electron microscopy revealed an important grain-boundary feature which eliminated the weak-link behavior. Large amounts of dislocations have also been found in the zone-melted sample which may contribute to flux pinning in the system

  14. Brain Microstructural Abnormalities Are Related to Physiological Alterations in End-Stage Renal Disease.

    Directory of Open Access Journals (Sweden)

    Zhigang Bai

    Full Text Available To study whole-brain microstructural alterations in patients with end-stage renal disease (ESRD and examine the relationship between brain microstructure and physiological indictors in the disease.Diffusion tensor imaging data were collected from 35 patients with ESRD (28 men, 18-61 years and 40 age- and gender-matched healthy controls (HCs, 32 men, 22-58 years. A voxel-wise analysis was then used to identify microstructural alterations over the whole brain in the ESRD patients compared with the HCs. Multiple biochemical measures of renal metabolin, vascular risk factors, general cognitive ability and dialysis duration were correlated with microstructural integrity for the patients.Compared to the HCs, the ESRD patients exhibited disrupted microstructural integrity in not only white matter (WM but also gray matter (GM regions, as characterized by decreased fractional anisotropy (FA and increased mean diffusivity (MD, axial diffusivity (AD and radial diffusivity (RD. Further correlation analyses revealed that the in MD, AD and RD values showed significantly positive correlations with the blood urea nitrogen in the left superior temporal gyrus and significantly negative correlations with the calcium levels in the left superior frontal gyrus (orbital part in the patients.Our findings suggest that ESRD is associated with widespread diffusion abnormalities in both WM and GM regions in the brain, and microstructural integrity of several GM regions are related to biochemical alterations in the disease.

  15. Miscibility gap alloys with inverse microstructures and high thermal conductivity for high energy density thermal storage applications

    International Nuclear Information System (INIS)

    Sugo, Heber; Kisi, Erich; Cuskelly, Dylan

    2013-01-01

    New high energy-density thermal storage materials are proposed which use miscibility gap binary alloy systems to operate through the latent heat of fusion of one component dispersed in a thermodynamically stable matrix. Using trial systems Al–Sn and Fe–Cu, we demonstrate the development of the required inverse microstructure (low melting point phase embedded in high melting point matrix) and excellent thermal storage potential. Several other candidate systems are discussed. It is argued that such systems offer enhancement over conventional phase change thermal storage by using high thermal conductivity microstructures (50–400 W/m K); minimum volume of storage systems due to high energy density latent heat of fusion materials (0.2–2.2 MJ/L); and technical utility through adaptability to a great variety of end uses. Low (<300 °C), mid (300–400 °C) and high (600–1400 °C) temperature options exist for applications ranging from space heating and process drying to concentrated solar thermal energy conversion and waste heat recovery. -- Highlights: ► Alloys of immiscible metals are proposed as thermal storage systems. ► High latent heat of fusion per unit volume and tunable temperature are advantageous. ► Thermal storage systems with capacities of 0.2–2.2 MJ/L are identified. ► Heat delivery is via a rigid non-reactive high thermal conductivity matrix. ► The required inverse microstructures were developed for Sn–Al and Cu–Fe systems

  16. STRAIGHTENING THE DENSITY-DISPLACEMENT RELATION WITH A LOGARITHMIC TRANSFORM

    International Nuclear Information System (INIS)

    Falck, Bridget L.; Neyrinck, Mark C.; Aragon-Calvo, Miguel A.; Lavaux, Guilhem; Szalay, Alexander S.

    2012-01-01

    We investigate the use of a logarithmic density variable in estimating the Lagrangian displacement field motivated by the success of a logarithmic transformation in restoring information to the matter power spectrum. The logarithmic relation is an extension of the linear relation, motivated by the continuity equation, in which the density field is assumed to be proportional to the divergence of the displacement field; we compare the linear and logarithmic relations by measuring both of these fields directly in a cosmological N-body simulation. The relative success of the logarithmic and linear relations depends on the scale at which the density field is smoothed. Thus we explore several ways of measuring the density field, including Cloud-In-Cell smoothing, adaptive smoothing, and the (scale-independent) Delaunay tessellation, and we use both a Fourier-space and a geometrical tessellation approach to measuring the divergence. We find that the relation between the divergence of the displacement field and the density is significantly tighter and straighter with a logarithmic density variable, especially at low redshifts and for very small (∼2 h –1 Mpc) smoothing scales. We find that the grid-based methods are more reliable than the tessellation-based method of calculating both the density and the divergence fields, though in both cases the logarithmic relation works better in the appropriate regime, which corresponds to nonlinear scales for the grid-based methods and low densities for the tessellation-based method.

  17. Effect of the hydration temperature on the microstructure of Class G cement: C-S-H composition and density

    International Nuclear Information System (INIS)

    Bahafid, Sara; Ghabezloo, Siavash; Duc, Myriam; Faure, Pamela; Sulem, Jean

    2017-01-01

    Curing temperature has a significant influence on cement paste microstructure and the properties of its principal hydrate C-S-H. In this paper, the effect of the hydration temperature in the range of 7 °C to 90 °C on the microstructure of a class G oil-well cement is studied. This is done by combining various experimental methods, including X-ray diffraction associated with the Rietveld analysis, thermo-gravimetric analysis, mercury intrusion porosimetry and porosity evaluation by drying. The experimental results show an increase of the capillary porosity and a decrease of the gel porosity by increasing the hydration temperature. This is attributed to a decrease of the C-S-H intrinsic porosity and a corresponding increase of the C-S-H density for higher curing temperatures. The experimental results are used in a simple analysis method to evaluate the density of C-S-H, as well as its C/S ratio and H/S ratio in dry and saturated conditions. The evaluated C-S-H density varies from 1.88 g/cm 3 at 7 °C to 2.10 g/cm 3 at 90 °C. The results also show a decrease of molar C/S ratio with increasing hydration temperature from 1.93 at 7 °C to 1.71 at 90 °C and of the H/S ratio from 5.1 at 7 °C to 2.66 at 90 °C.

  18. Effect of current density on the microstructure and corrosion resistance of microarc oxidized ZK60 magnesium alloy.

    Science.gov (United States)

    You, Qiongya; Yu, Huijun; Wang, Hui; Pan, Yaokun; Chen, Chuanzhong

    2014-09-01

    The application of magnesium alloys as biomaterials is limited by their poor corrosion behavior. Microarc oxidation (MAO) treatment was used to prepare ceramic coatings on ZK60 magnesium alloys in order to overcome the poor corrosion resistance. The process was conducted at different current densities (3.5 and 9.0 A/dm(2)), and the effect of current density on the process was studied. The microstructure, elemental distribution, and phase composition of the MAO coatings were characterized by scanning electron microscopy, energy-dispersive x-ray spectrometry, and x-ray diffraction, respectively. The increment of current density contributes to the increase of thickness. A new phase Mg2SiO4 was detected as the current density increased to 9.0 A/dm(2). A homogeneous distribution of micropores could be observed in the coating produced at 3.5 A/dm(2), while the surface morphology of the coating formed at 9.0 A/dm(2) was more rough and apparent microcracks could be observed. The coating obtained at 3.5 A/dm(2) possessed a better anticorrosion behavior.

  19. Scaling relations between trabecular bone volume fraction and microstructure at different skeletal sites.

    Science.gov (United States)

    Räth, Christoph; Baum, Thomas; Monetti, Roberto; Sidorenko, Irina; Wolf, Petra; Eckstein, Felix; Matsuura, Maiko; Lochmüller, Eva-Maria; Zysset, Philippe K; Rummeny, Ernst J; Link, Thomas M; Bauer, Jan S

    2013-12-01

    In this study, we investigated the scaling relations between trabecular bone volume fraction (BV/TV) and parameters of the trabecular microstructure at different skeletal sites. Cylindrical bone samples with a diameter of 8mm were harvested from different skeletal sites of 154 human donors in vitro: 87 from the distal radius, 59/69 from the thoracic/lumbar spine, 51 from the femoral neck, and 83 from the greater trochanter. μCT images were obtained with an isotropic spatial resolution of 26μm. BV/TV and trabecular microstructure parameters (TbN, TbTh, TbSp, scaling indices ( and σ of α and αz), and Minkowski Functionals (Surface, Curvature, Euler)) were computed for each sample. The regression coefficient β was determined for each skeletal site as the slope of a linear fit in the double-logarithmic representations of the correlations of BV/TV versus the respective microstructure parameter. Statistically significant correlation coefficients ranging from r=0.36 to r=0.97 were observed for BV/TV versus microstructure parameters, except for Curvature and Euler. The regression coefficients β were 0.19 to 0.23 (TbN), 0.21 to 0.30 (TbTh), -0.28 to -0.24 (TbSp), 0.58 to 0.71 (Surface) and 0.12 to 0.16 (), 0.07 to 0.11 (), -0.44 to -0.30 (σ(α)), and -0.39 to -0.14 (σ(αz)) at the different skeletal sites. The 95% confidence intervals of β overlapped for almost all microstructure parameters at the different skeletal sites. The scaling relations were independent of vertebral fracture status and similar for subjects aged 60-69, 70-79, and >79years. In conclusion, the bone volume fraction-microstructure scaling relations showed a rather universal character. © 2013.

  20. Smart density: A more accurate method of measuring rural residential density for health-related research.

    Science.gov (United States)

    Owens, Peter M; Titus-Ernstoff, Linda; Gibson, Lucinda; Beach, Michael L; Beauregard, Sandy; Dalton, Madeline A

    2010-02-12

    Studies involving the built environment have typically relied on US Census data to measure residential density. However, census geographic units are often unsuited to health-related research, especially in rural areas where development is clustered and discontinuous. We evaluated the accuracy of both standard census methods and alternative GIS-based methods to measure rural density. We compared residential density (units/acre) in 335 Vermont school neighborhoods using conventional census geographic units (tract, block group and block) with two GIS buffer measures: a 1-kilometer (km) circle around the school and a 1-km circle intersected with a 100-meter (m) road-network buffer. The accuracy of each method was validated against the actual residential density for each neighborhood based on the Vermont e911 database, which provides an exact geo-location for all residential structures in the state. Standard census measures underestimate residential density in rural areas. In addition, the degree of error is inconsistent so even the relative rank of neighborhood densities varies across census measures. Census measures explain only 61% to 66% of the variation in actual residential density. In contrast, GIS buffer measures explain approximately 90% of the variation. Combining a 1-km circle with a road-network buffer provides the closest approximation of actual residential density. Residential density based on census units can mask clusters of development in rural areas and distort associations between residential density and health-related behaviors and outcomes. GIS-defined buffers, including a 1-km circle and a road-network buffer, can be used in conjunction with census data to obtain a more accurate measure of residential density.

  1. Smart density: a more accurate method of measuring rural residential density for health-related research

    Directory of Open Access Journals (Sweden)

    Gibson Lucinda

    2010-02-01

    Full Text Available Abstract Background Studies involving the built environment have typically relied on US Census data to measure residential density. However, census geographic units are often unsuited to health-related research, especially in rural areas where development is clustered and discontinuous. Objective We evaluated the accuracy of both standard census methods and alternative GIS-based methods to measure rural density. Methods We compared residential density (units/acre in 335 Vermont school neighborhoods using conventional census geographic units (tract, block group and block with two GIS buffer measures: a 1-kilometer (km circle around the school and a 1-km circle intersected with a 100-meter (m road-network buffer. The accuracy of each method was validated against the actual residential density for each neighborhood based on the Vermont e911 database, which provides an exact geo-location for all residential structures in the state. Results Standard census measures underestimate residential density in rural areas. In addition, the degree of error is inconsistent so even the relative rank of neighborhood densities varies across census measures. Census measures explain only 61% to 66% of the variation in actual residential density. In contrast, GIS buffer measures explain approximately 90% of the variation. Combining a 1-km circle with a road-network buffer provides the closest approximation of actual residential density. Conclusion Residential density based on census units can mask clusters of development in rural areas and distort associations between residential density and health-related behaviors and outcomes. GIS-defined buffers, including a 1-km circle and a road-network buffer, can be used in conjunction with census data to obtain a more accurate measure of residential density.

  2. Cell behavior related to implant surfaces with different microstructure and chemical composition: an in vitro analysis.

    Science.gov (United States)

    Conserva, Enrico; Lanuti, Anna; Menini, Maria

    2010-01-01

    This paper reports on an in vitro comparison of osteoblast and mesenchymal stem cell (MSC) adhesion, proliferation, and differentiation related to two different surface treatments applied to the same implant design to determine whether the interaction between cells and implants is influenced by surface structure and chemical composition of the implants. Thirty-nine implants with a sandblasted (SB) surface and 39 implants with a grit-blasted and high-temperature acid-etched (GBAE) surface were used. The implant macrostructures and microstructures were analyzed by high- and low-voltage scanning electron microscopy (SEM) and by stereo-SEM. The surface chemical composition was investigated by energy dispersive analysis and x-ray photoemission spectroscopy. SaOS-2 osteoblasts and human MSCs were used for the evaluation of cell proliferation and alkaline phosphatase enzymatic activity in contact with the two surfaces. The GBAE surface showed fewer contaminants and a very high percentage of titanium (19.7%) compared to the SB surface (14.2%). The two surfaces showed similar mean roughness (Ra), but the depth (Rz) and density (RSm) of the porosity were significantly increased in the GBAE surface. The GBAE surface presented more osteoblast and MSC proliferation than the SB surface. No statistically significant differences in alkaline phosphatase activity were found between surfaces for either cellular line. The GBAE surface showed less surface contaminants and a higher percentage of titanium (19.7%) than the SB surface. The macro/micropore structured design and chemical composition of the GBAE surface allowed greater cell adhesion and proliferation and an earlier cell spreading but did not play an obvious role in in vitro cellular differentiation.

  3. Irradiated microstructure of U-10Mo monolithic fuel plate at very high fission density

    Science.gov (United States)

    Gan, J.; Miller, B. D.; Keiser, D. D.; Jue, J. F.; Madden, J. W.; Robinson, A. B.; Ozaltun, H.; Moore, G.; Meyer, M. K.

    2017-08-01

    Monolithic U-10Mo alloy fuel plates with Al-6061 cladding are being developed for use in research and test reactors as low enrichment fuel (RERTR-9B experiment. This paper discusses the TEM characterization results for this U-10Mo/Zr/Al6061 monolithic fuel plate (∼59% U-235 enrichment) irradiated in Advanced Test Reactor at Idaho National Laboratory with an unprecedented high local fission density of 9.8E+21 fissions/cm3. The calculated fuel foil centerline temperature at the beginning of life and the end of life is 141 and 194 °C, respectively. TEM lamellas were prepared using focus ion beam lift-out technique. The estimated U-Mo fuel swelling, based on the fuel foil thickness change from SEM, is approximately 76%. Large bubbles (>1 μm) are distributed evenly in U-Mo and interlink of these bubbles is evident. The average size of subdivided grains at this fission density appears similar to that at 5.2E+21 fissions/cm3. The measured average Mo and Zr content in the fuel matrix is ∼30 at% and ∼7 at%, respectively, in general agreement with the calculated Mo and Zr from fission density.

  4. Age-related changes in vertebral and iliac crest 3D bone microstructure-differences and similarities

    DEFF Research Database (Denmark)

    Thomsen, Jesper Skovhus; Jensen, Michael Vinkel; Niklassen, Andreas Steenholt

    2015-01-01

    Summary Age-related changes of vertebra and iliac crest 3D microstructure were investigated, and we showed that they were in general similar. The 95th percentile of vertebral trabecular thickness distribution increased with age for women. Surprisingly, vertebral and iliac crest bone microstructure...... was only weakly correlated (r = 0.38 to 0.75), despite the overall similar age-related changes.Introduction The purposes of the study were to determine the age-related changes in iliac and vertebral bone microstructure for women and men over a large age range and to investigate the relationship between...... the bone microstructure at these skeletal sites.Methods Matched sets of transiliac crest bone biopsies and lumbar vertebral body (L2) specimens from 41 women (19–96 years) and 39 men (23–95 years) were micro-computed tomography (μCT) scanned, and the 3D microstructure was quantified.Results For both women...

  5. Irradiated microstructure of U-10Mo monolithic fuel plate at very high fission density

    Energy Technology Data Exchange (ETDEWEB)

    Gan, J.; Miller, B. D.; Keiser, D. D.; Jue, J. F.; Madden, J. W.; Robinson, A. B.; Ozaltun, H.; Moore, G.; Meyer, M. K.

    2017-08-01

    Monolithic U-10Mo alloy fuel plates with Al-6061 cladding are being developed for use in research and test reactors as low enrichment fuel (< 20% U-235 enrichment) as a result of its high uranium loading capacity compared to that of U-7Mo dispersion fuel. These fuel plates contain a Zr diffusion barrier between the U-10Mo fuel and Al-6061 cladding that suppresses the interaction between the U-Mo fuel foil and Al alloy cladding that is known to be problematic under irradiation. This paper discusses the TEM results of the U-10Mo/Zr/Al6061 monolithic fuel plate (Plate ID: L1P09T, ~ 59% U-235 enrichment) irradiated in Advanced Test Reactor at Idaho National Laboratory as part of RERTR-9B irradiation campaign with an unprecedented high local fission density of 9.8E+21 fissions/cm3. The calculated fuel foil centerline temperature at the beginning of life and the end of life is 141 and 194 C, respectively. A total of 5 TEM lamellas were prepared using focus ion beam lift-out technique. The estimated U-Mo fuel swelling, based on the fuel foil thickness change from SEM, is approximately 76%. Large bubbles (> 1 µm) are distributed evenly in U-Mo and interlink of these bubbles is evident. The average size of subdivided grains at this fission density appears similar to that at 5.2E+21 fissions/cm3. The measured average Mo and Zr content in the fuel matrix is ~ 30 at% and ~ 7 at%, respectively, in general agreement with the calculated Mo and Zr from fission density.

  6. Analytical relation between effective mode field area and waveguide dispersion in microstructure fibers.

    Science.gov (United States)

    Moenster, Mathias; Steinmeyer, Günter; Iliew, Rumen; Lederer, Falk; Petermann, Klaus

    2006-11-15

    For optical fibers exhibiting a radially symmetric refractive index profile, there exists an analytical relation that connects waveguide dispersion and the Petermann-II mode field radius. We extend the usefulness of this relation to the nonradially symmetric case of microstructure fibers in the anomalous dispersion regime, yielding a simple relation between dispersion and effective mode field area. Assuming a Gaussian mode distribution, we derive a fundamental upper limit for the effective mode field area that is required to obtain a certain amount of anomalous waveguide dispersion. This relation is demonstrated to show excellent agreement for fiber designs suited for supercontinuum generation and soliton lasers in the near infrared.

  7. Annual Screening Mammogram and its Relation to Breast Density

    Directory of Open Access Journals (Sweden)

    Sabek EAS

    2017-11-01

    Full Text Available Background: Current national screening programs totally depend on mammographic evaluation. After increased incidence of breast cancer in women under the age of 35, mammography sensitivity in now a question. Several factors added to decrease sensitivity of mammography, such as increased density in older age groups and increased aggressiveness of tumour biology. All these factors will change the reliability of the screening program. The study is a retrospective study conducted at Ain Shams University. Method: 138 patients diagnosed with cancer breast underwent both mammography and sonography to determine percentage of patient with more than one focus, age and density distribution breast cancer in the affected patient and accuracy of both mammography and US. Results: By studying this population, we found that around 61,44% have areas of density ranging from dense breast, heterogenous density or scattered density. These areas of density render the mammography a less sensitive tool as its sensitivity fall to 34.09%, while that of US was 77.27%. Conclusion: As breast cancer is prevalent in younger population, also with increased density in older population who are relatively insensitive to mammography, we recommended the use of Automated Breast Ultrasound (ABUS in the national screening program.

  8. Assessment of Choroidal Microstructure and Subfoveal Thickness Change in Eyes With Different Stages of Age-Related Macular Degeneration.

    Science.gov (United States)

    Lu, Linna; Xu, Shiqiong; He, Fangling; Liu, Yan; Zhang, Yidan; Wang, Jing; Wang, Zhiliang; Fan, Xianqun

    2016-03-01

    Age-related macular degeneration (AMD) is a major cause of irreversible blindness. Choroidal structural changes seem to be inevitable in AMD pathogenesis. Our study revealed associated choroidal microstructural changes in AMD eyes.The aim of the study was to compare choroidal microstructural changes in eyes with AMD of different stages.The study was a retrospective, cross-sectional case series.The participants comprised of 32 age-matched normal eyes as controls, and 26 fellow uninvolved eyes of intermediate/late AMD, 29 of early AMD, 28 of intermediate AMD, and 39 of late AMD.All subjects underwent comprehensive ophthalmologic examination. The choroid images, including subfoveal choroidal thickness, percentage of Sattler layer area, and en face images of the choroid, were obtained using spectral-domain optical coherence tomography.The main outcome measures were subfoveal choroidal thickness changes, percentage of Sattler layer area changes, and en face images of the choroid in AMD eyes.One hundred fifty-four eyes of 96 individuals with mean age of 67.1±9.2 years were included. The mean subfoveal choroidal thickness was 295.4 ± 56.8 μm in age-matched normal eyes, 306.7 ± 68.4 μm in fellow uninvolved eyes with AMD, 293.8 ± 80.4 μm in early AMD, 215.6 ± 80.4 μm in intermediate AMD, and 200.4 ± 66.6 μm in late AMD (F = 14.2, all P < 0.001). Choroidal thickness was greater in early AMD eyes than in intermediate/late AMD eyes (P < 0.001). Mean percentage of Sattler layer area in each group showed a similar tendency. Microstructure of the choroid showed reduced vascular density of Sattler layer areas in late AMD eyes compared with normal eyes.Decreasing subfoveal choroidal thickness and percentage of Sattler layer area were demonstrated in the progression of AMD. The choroidal change was related to atrophy of the microstructural changes of underlying capillaries and medium-sized vessels.

  9. Microstructural characteristics of PWR [pressurized water reactor] spent fuel relative to its leaching behavior

    International Nuclear Information System (INIS)

    Wilson, C.N.

    1986-01-01

    Microstructural, compositional and thermochemical properties of spent nuclear fuel are discussed relative to its potential performance as a high-level waste form under proposed Nevada Nuclear Waste Storage Investigations Project tuff repository conditions. Pressurized water reactor spent fuel specimens with various artificially induced cladding defects were leach tested in deionized water and in a reference tuff groundwater under ambient hot cell air and temperature conditions. Greater fractional actinide release was observed with bare fuel than with clad fuel leached through a cladding defect. Congruent actinide release and preferential release of cesium and technetium were observed in both water types. Selected summary radionuclide release data are presented and correlated to pre- and post-test microstructural characterization data

  10. Hippocampus age-related microstructural changes in schizophrenia: a case-control mean diffusivity study.

    Science.gov (United States)

    Chiapponi, Chiara; Piras, Fabrizio; Fagioli, Sabrina; Girardi, Paolo; Caltagirone, Carlo; Spalletta, Gianfranco

    2014-08-01

    Macrostructural-volumetric abnormalities of the hippocampus have been described in schizophrenia. Here, we characterized age-related changes of hippocampal mean diffusivity as an index of microstructural damage by carrying out a neuroimaging study in 85 patients with a DSM-IV-TR diagnosis of schizophrenia and 85 age- and gender-matched healthy controls. We performed analyses of covariance, with diagnosis as fixed factor, mean diffusivity as dependent variable and age as covariate. Patients showed an early increase in mean diffusivity in the right and left hippocampus that increased with age. Thus, microstructural hippocampal changes associated with schizophrenia cannot be confined to a specific time window. Copyright © 2014 Elsevier B.V. All rights reserved.

  11. Neural Networks Relating Alloy Composition, Microstructure, and Tensile Properties of α/ β-Processed TIMETAL 6-4

    Science.gov (United States)

    Collins, Peter C.; Koduri, Santhosh; Welk, Brian; Tiley, Jaimie; Fraser, Hamish L.

    2013-03-01

    Bayesian neural networks have been developed, which relate composition, microstructure, and tensile properties of the alloy TIMETAL 6-4 (nominal composition: Ti-6Al-4V (wt pct) after thermomechanical processing (TMP) in the two-phase ( α + β)-phase field. The developed networks are able to make interpolative predictions of properties within the ranges of composition and microstructural features that are in the population of the database used for training and testing of the networks. In addition, the neural networks have been used to conduct virtual experiments which permit the functional dependencies of properties on composition and microstructural features to be determined. In this way, it is shown that in the microstructural condition resulting from TMP in the two-phase ( α + β) phase field, the most significant contribution to strength is from solid solution strengthening, with microstructural features apparently influencing the balance of a number of properties.

  12. Spinning solutions in general relativity with infinite central density

    Science.gov (United States)

    Flammer, P. D.

    2018-05-01

    This paper presents general relativistic numerical simulations of uniformly rotating polytropes. Equations are developed using MSQI coordinates, but taking a logarithm of the radial coordinate. The result is relatively simple elliptical differential equations. Due to the logarithmic scale, we can resolve solutions with near-singular mass distributions near their center, while the solution domain extends many orders of magnitude larger than the radius of the distribution (to connect with flat space-time). Rotating solutions are found with very high central energy densities for a range of adiabatic exponents. Analytically, assuming the pressure is proportional to the energy density (which is true for polytropes in the limit of large energy density), we determine the small radius behavior of the metric potentials and energy density. This small radius behavior agrees well with the small radius behavior of large central density numerical results, lending confidence to our numerical approach. We compare results with rotating solutions available in the literature, which show good agreement. We study the stability of spherical solutions: instability sets in at the first maximum in mass versus central energy density; this is also consistent with results in the literature, and further lends confidence to the numerical approach.

  13. The epoxy resin variation effect on microstructure and physical properties to improve bonded NdFeB flux magnetic density

    International Nuclear Information System (INIS)

    Rusnaeni, N.; Sarjono, Priyo; Muljadi; Noer, Nasrudin

    2016-01-01

    NdFeB magnets have been fabricated from a mixture of powder NdFeB (MPQ-B+) and epoxy resins (ER) with a variation of 0% wt, 2% wt, 4% wt and 6% wt. The pellets samples were made by pressing 4 tons of the mixture powder at room temperature before curing at 100°C for 1 hour. The SEM-EDX results showed the microstructure with ER were evenly smeared the NdFeB magnetic particles due to higher percent C and lower transition metals value. Sample with 2% wt epoxy resin was able to achieve the highest density of 5.35 g/cm 3 and the highest magnetic flux of 2121 Gauss. The magnetic properties characterization using the permagraph indicates that the sample pellets with 2% wt epoxy resin has a value of remanence (Br) = 4.92 kG, coercivity (Hc) = 7.76 kOe, and energy product (Bhmax) = 4.58 MGOe. Despite low remanence value in the pellet samples, the resistance to demagnetization value was still acceptable. (paper)

  14. The epoxy resin variation effect on microstructure and physical properties to improve bonded NdFeB flux magnetic density

    Science.gov (United States)

    Rusnaeni, N.; Sarjono, Priyo; Muljadi; Noer, Nasrudin

    2016-11-01

    NdFeB magnets have been fabricated from a mixture of powder NdFeB (MPQ-B+) and epoxy resins (ER) with a variation of 0% wt, 2% wt, 4% wt and 6% wt. The pellets samples were made by pressing 4 tons of the mixture powder at room temperature before curing at 100°C for 1 hour. The SEM-EDX results showed the microstructure with ER were evenly smeared the NdFeB magnetic particles due to higher percent C and lower transition metals value. Sample with 2% wt epoxy resin was able to achieve the highest density of 5.35 g/cm3 and the highest magnetic flux of 2121 Gauss. The magnetic properties characterization using the permagraph indicates that the sample pellets with 2% wt epoxy resin has a value of remanence (Br) = 4.92 kG, coercivity (Hc) = 7.76 kOe, and energy product (Bhmax) = 4.58 MGOe. Despite low remanence value in the pellet samples, the resistance to demagnetization value was still acceptable.

  15. The relation between food price, energy density and diet quality

    Directory of Open Access Journals (Sweden)

    Margareta Bolarić

    2013-01-01

    Full Text Available Low energy density diet, high in fruits and vegetables, is related to lower obesity risk and to better health status, but is more expensive. High energy density diet, high in added sugar and fats, is more affordable, but is related to higher obesity and chronic diseases risk. The aim of this study was to report prices according to energy density (low vs. high of food items and to show how food affordability could affect food choice and consumers’ health. Data was collected for 137 raw and processed foods from three purchase sites in Zagreb (one representative for supermarket, one smaller shop and green market. Results showed that low energy density food is more expensive than high energy density food (for example, the price of 1000 kcal from green zucchini (15 kcal/100 g is 124.20 kn while the price of 1000 kcal from sour cream (138 kcal/100 g is 13.99 kn. Food energy price was significantly different (p<0.05 between food groups with highest price for vegetable products (159.04 ± 36.18 kn/1000 kcal and raw vegetables (97.90 ± 50.13 kn/1000 kcal and lowest for fats (8.49 ± 1.22 kn/1000 kcal and cereals and products (5.66 ± 0.76 kn/1000 kcal. Negative correlation (Spearman r=-0.72, p<0.0001 was observed for energy density (kcal/100 g and price of 1000 kcal. Therefore, it is advisable to develop strategies in order to reduce price of low energy density food and encourage its intake since it would improve diet quality, which could lead to better costumers’ health.

  16. Nutrient density of beverages in relation to climate impact

    Directory of Open Access Journals (Sweden)

    Annika Smedman

    2010-08-01

    Full Text Available The food chain contributes to a substantial part of greenhouse gas (GHG emissions and growing evidence points to the urgent need to reduce GHGs emissions worldwide. Among suggestions were proposals to alter food consumption patterns by replacing animal foods with more plant-based foods. However, the nutritional dimensions of changing consumption patterns to lower GHG emissions still remains relatively unexplored. This study is the first to estimate the composite nutrient density, expressed as percentage of Nordic Nutrition Recommendations (NNR for 21 essential nutrients, in relation to cost in GHG emissions of the production from a life cycle perspective, expressed in grams of CO2-equivalents, using an index called the Nutrient Density to Climate Impact (NDCI index. The NDCI index was calculated for milk, soft drink, orange juice, beer, wine, bottled carbonated water, soy drink, and oat drink. Due to low-nutrient density, the NDCI index was 0 for carbonated water, soft drink, and beer and below 0.1 for red wine and oat drink. The NDCI index was similar for orange juice (0.28 and soy drink (0.25. Due to a very high-nutrient density, the NDCI index for milk was substantially higher (0.54 than for the other beverages. Future discussion on how changes in food consumption patterns might help avert climate change need to take both GHG emission and nutrient density of foods and beverages into account.

  17. Microstructural changes and strain hardening effects in abrasive contacts at different relative velocities and temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Rojacz, H., E-mail: rojacz@ac2t.at [AC2T research GmbH, Viktor-Kaplan-Straße 2C, 2700 Wiener Neustadt (Austria); Mozdzen, G. [Aerospace & Advanced Composites GmbH, Viktor-Kaplan-Straße 2F, 2700 Wiener Neustadt (Austria); Weigel, F.; Varga, M. [AC2T research GmbH, Viktor-Kaplan-Straße 2C, 2700 Wiener Neustadt (Austria)

    2016-08-15

    Strain hardening is commonly used to reach the full potential of materials and can be beneficial in tribological contacts. 2-body abrasive wear was simulated in a scratch test, aimed at strain hardening effects in various steels. Different working conditions were examined at various temperatures and velocities. Strain hardening effects and microstructural changes were analysed with high resolution scanning electron microscopy (HRSEM), electron backscatter diffraction (EBSD), micro hardness measurements and nanoindentation. Statistical analysing was performed quantifying the influence of different parameters on microstructures. Results show a crucial influence of temperature and velocity on the strain hardening in tribological contacts. Increased velocity leads to higher deformed microstructures and higher increased surface hardness at a lower depth of the deformed zones at all materials investigated. An optimised surface hardness can be achieved knowing the influence of velocity (strain rate) and temperature for a “tailor-made” surface hardening in tribological systems aimed at increased wear resistance. - Highlights: •Hardening mechanisms and their intensity in tribological contacts are dependent on relative velocity and temperature. •Beneficial surface hardened zones are formed at certain running-in conditions; the scientific background is presented here. •Ferritic-pearlitic steels strain hardens via grain size reduction and decreasing interlamellar distances in pearlite. •Austenitic steels show excellent surface hardening (120% hardness increase) by twinning and martensitic transformation. •Ferritic steels with hard phases harden in the ferrite phase as per Hall-Petch equation and degree of deformation.

  18. Microstructural changes and strain hardening effects in abrasive contacts at different relative velocities and temperatures

    International Nuclear Information System (INIS)

    Rojacz, H.; Mozdzen, G.; Weigel, F.; Varga, M.

    2016-01-01

    Strain hardening is commonly used to reach the full potential of materials and can be beneficial in tribological contacts. 2-body abrasive wear was simulated in a scratch test, aimed at strain hardening effects in various steels. Different working conditions were examined at various temperatures and velocities. Strain hardening effects and microstructural changes were analysed with high resolution scanning electron microscopy (HRSEM), electron backscatter diffraction (EBSD), micro hardness measurements and nanoindentation. Statistical analysing was performed quantifying the influence of different parameters on microstructures. Results show a crucial influence of temperature and velocity on the strain hardening in tribological contacts. Increased velocity leads to higher deformed microstructures and higher increased surface hardness at a lower depth of the deformed zones at all materials investigated. An optimised surface hardness can be achieved knowing the influence of velocity (strain rate) and temperature for a “tailor-made” surface hardening in tribological systems aimed at increased wear resistance. - Highlights: •Hardening mechanisms and their intensity in tribological contacts are dependent on relative velocity and temperature. •Beneficial surface hardened zones are formed at certain running-in conditions; the scientific background is presented here. •Ferritic-pearlitic steels strain hardens via grain size reduction and decreasing interlamellar distances in pearlite. •Austenitic steels show excellent surface hardening (120% hardness increase) by twinning and martensitic transformation. •Ferritic steels with hard phases harden in the ferrite phase as per Hall-Petch equation and degree of deformation.

  19. Misorientation related microstructure at the grain boundary in a nickel-based single crystal superalloy

    International Nuclear Information System (INIS)

    Huang, Ming; Zhuo, Longchao; Liu, Zhanli; Lu, Xiaogang; Shi, Zhenxue; Li, Jiarong; Zhu, Jing

    2015-01-01

    The mechanical properties of nickel-based single crystal superalloys deteriorate with increasing misorientation, thus the finished product rate of the casting of single crystal turbine airfoils may be reduced due to the formation of grain boundaries especially when the misorientation angle exceeds to some extent. To this day, evolution of the microstructures at the grain boundaries with misorientation and the relationship between the microstructures and the mechanical properties are still unclear. In this work a detailed characterization of the misorientation related microstructure at the grain boundary in DD6 single crystal superalloy has been carried out using scanning electron microscopy (SEM) and transmission electron microscopy (TEM) techniques; the elemental distribution at the grain boundaries has been analyzed by energy dispersive (EDS) X-ray mapping; and the effect of precipitation of μ phases at the grain boundary on the mechanical property has been evaluated by finite element calculation. It is shown that the proportion of γ phase at the grain boundaries decreases, while the proportion of γ′ phase at the grain boundaries increases with increasing misorientation; the μ phase is precipitated at the grain boundaries when the misorientation angle exceeds about 10° and thus it could lead to a dramatic deterioration of the mechanical properties, as well as that the enrichment of Re and W gradually disappears as the misorientation angle increases. All these factors may result in the degradation of the mechanical properties at the grain boundaries as the misorientation increases. Furthermore, the finite element calculation confirms that precipitation of μ phases at the grain boundary is responsible for the significant deterioration of the mechanical properties when the misorientation exceeds about 10°. This work provides a physical imaging of the microstructure for understanding the relationship between the mechanical properties and the misorientation

  20. Disease-Related Microstructural Differences in the Brain in Women With Provoked Vestibulodynia.

    Science.gov (United States)

    Gupta, Arpana; Woodworth, Davis C; Ellingson, Benjamin M; Rapkin, Andrea J; Naliboff, Bruce; Kilpatrick, Lisa A; Stains, Jean; Masghati, Salome; Tillisch, Kirsten; Mayer, Emeran A; Labus, Jennifer S

    2018-05-01

    Provoked vestibulodynia (PVD) is a chronic pelvic pain disorder affecting 16% of the female population. Neuroimaging studies have highlighted central abnormalities in PVD, similar to other chronic pelvic pain disorders, including brain regions involved in sensory processing and modulation of pain. The aim of the study was to determine alterations in the subvoxel, microstructural organization within tissues in PVD compared with healthy control participants (HCs) and a disease control group (irritable bowel syndrome [IBS]). Diffusion tensor imaging magnetic resonance imaging was conducted in 87 age-matched premenopausal women (29 PVD, 29 HCs, 29 IBS). Statistical parameter mapping of fractional anisotropy (FA) and mean diffusivity (MD) maps were used to identify microstructural difference in the brain specific to PVD or shared with IBS. PVD alterations in microstructural organization of the brain were predominantly observed in fibers associated with sensorimotor integration and pain processing that relay information between the thalamus, basal ganglia, sensorimotor, and insular cortex. PVD, compared with HCs, showed extensive increases in the FA of somatosensory and basal ganglia regions. In contrast, PVD and IBS subjects did not show any FA-related group differences. PVD subjects showed greater MD in the basal ganglia compared with HCs (higher MD in the internal capsule and pallidum) and IBS (higher MD in the putamen and pallidum). Increases in MD were associated with increased vaginal muscle tenderness and vulvar pain. The current findings highlight possible shared mechanisms between 2 different pelvic pain disorders, but also highlight the widespread alterations observed specifically in PVD compared with HCs. Alterations in microstructure in PVD were observed in fibers associated with sensorimotor integration and pain processing, which were also associated with increased vaginal muscle tenderness and vulvar pain. These alterations may be contributing to increased

  1. Dispersal patterns of red foxes relative to population density

    Science.gov (United States)

    Allen, Stephen H.; Sargeant, Alan B.

    1993-01-01

    Factors affecting red fox (Vulpes vulpes) dispersal patterns are poorly understood but warranted investigation because of the role of dispersal in rebuilding depleted populations and transmission of diseases. We examined dispersal patterns of red foxes in North Dakota based on recoveries of 363 of 854 foxes tagged as pups and relative to fox density. Foxes were recovered up to 8.6 years after tagging; 79% were trapped or shot. Straight-line distances between tagging and recovery locations ranged from 0 to 302 km. Mean recovery distances increased with age and were greater for males than females, but longest individual recovery distances were by females. Dispersal distances were not related to population density for males (P = 0.36) or females (P = 0.96). The proportion of males recovered that dispersed was inversely related to population density (r = -0.94; n = 5; P = 0.02), but not the proportion of females (r = -0.49; n = 5; P = 0.40). Dispersal directions were not uniform for either males (P = 0.003) or females (P = 0.006); littermates tended to disperse in similar directions (P = 0.09). A 4-lane interstate highway altered dispersal directions (P = 0.001). Dispersal is a strong innate behavior of red foxes (especially males) that results in many individuals of both sexes traveling far from natal areas. Because dispersal distance was unaffected by fox density, populations can be rebuilt and diseases transmitted long distances regardless of fox abundance.

  2. Ambiguities and symmetry relations associated with fermionic tensor densities

    International Nuclear Information System (INIS)

    Dallabona, G.; Battistel, O. A.

    2004-01-01

    We consider the consistent evaluation of perturbative (divergent) Green functions associated with fermionic tensor densities and the derivation of symmetry relations for them. We show that, in spite of current algebra methods being not applicable, it is possible to derive symmetry properties analogous to the Ward identities of vector and axial-vector densities. The proposed method, which is applicable to any previously chosen order of perturbative calculation, gives the same results as those of current algebra when such a tool is applicable. By using a very general calculational strategy, concerning the manipulations and calculations involving divergent Feynman integrals, we evaluate the purely fermionic two-point functions containing tensor vertices and derive their symmetry properties. The present investigation is the first step in the study and characterization of possible anomalies involving fermionic tensor densities, particularly in purely fermionic three-point functions

  3. Relating saturation capacity to charge density in strong cation exchangers.

    Science.gov (United States)

    Steinebach, Fabian; Coquebert de Neuville, Bertrand; Morbidelli, Massimo

    2017-07-21

    In this work the relation between physical and chemical resin characteristics and the total amount of adsorbed protein (saturation capacity) for ion-exchange resins is discussed. Eleven different packing materials with a sulfo-functionalization and one multimodal resin were analyzed in terms of their porosity, pore size distribution, ligand density and binding capacity. By specifying the ligand density and binding capacity by the total and accessible surface area, two different groups of resins were identified: Below a ligand density of approx. 2.5μmol/m 2 area the ligand density controls the saturation capacity, while above this limit the accessible surface area becomes the limiting factor. This results in a maximum protein uptake of around 2.5mg/m 2 of accessible surface area. The obtained results allow estimating the saturation capacity from independent resin characteristics like the saturation capacity mainly depends on "library data" such as the accessible and total surface area and the charge density. Hence these results give an insight into the fundamentals of protein adsorption and help to find suitable resins, thus limiting the experimental effort in early process development stages. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. Relational invariance of expressive microstructure across global tempo changes in music performance: an exploratory study.

    Science.gov (United States)

    Repp, B H

    1994-01-01

    This study addressed the question of whether the expressive microstructure of a music performance remains relationally invariant across moderate (musically acceptable) changes in tempo. Two pianists played Schumann's "Träumerei" three times at each of three tempi on a digital piano, and the performance data were recorded in MIDI format. In a perceptual test, musically trained listeners attempted to distinguish the original performances from performances that had been artificially speeded up or slowed down to the same overall duration. Accuracy in this task was barely above chance, suggesting that relational invariance was largely preserved. Subsequent analysis of the MIDI data confirmed that each pianist's characteristic timing patterns were highly similar across the three tempi, although there were statistically significant deviations from perfect relational invariance. The timing of (relatively slow) grace notes seemed relationally invariant, but selective examination of other detailed temporal features (chord asynchrony, tone overlap, pedal timing) revealed no systematic scaling with tempo. Finally, although the intensity profile seemed unaffected by tempo, a slight overall increase in intensity with tempo was observed. Effects of musical structure on expressive microstructure were large and pervasive at all levels, as were individual differences between the two pianists. For the specific composition and range of tempi considered here, these results suggest that major (cognitively controlled) temporal and dynamic features of a performance change roughly in proportion with tempo, whereas minor features tend to be governed by tempo-independent motoric constraints.

  5. On the link between column density distribution and density scaling relation in star formation regions

    Science.gov (United States)

    Veltchev, Todor; Donkov, Sava; Stanchev, Orlin

    2017-07-01

    We present a method to derive the density scaling relation ∝ L^{-α} in regions of star formation or in their turbulent vicinities from straightforward binning of the column-density distribution (N-pdf). The outcome of the method is studied for three types of N-pdf: power law (7/5≤α≤5/3), lognormal (0.7≲α≲1.4) and combination of lognormals. In the last case, the method of Stanchev et al. (2015) was also applied for comparison and a very weak (or close to zero) correlation was found. We conclude that the considered `binning approach' reflects rather the local morphology of the N-pdf with no reference to the physical conditions in a considered region. The rough consistency of the derived slopes with the widely adopted Larson's (1981) value α˜1.1 is suggested to support claims that the density-size relation in molecular clouds is indeed an artifact of the observed N-pdf.

  6. Executive Functions in Healthy Older Adults Are Differentially Related to Macro- and Microstructural White Matter Characteristics of the Cerebral Lobes

    Directory of Open Access Journals (Sweden)

    Sarah Hirsiger

    2017-11-01

    Full Text Available Aging is associated with microstructural white matter (WM changes. WM microstructural characteristics, measured with diffusion tensor imaging (DTI, are different in normal appearing white matter (NAWM and WM hyperintensities (WMH. It is largely unknown how the microstructural properties of WMH are associated with cognition and if there are regional effects for specific cognitive domains. We therefore examined within 200 healthy older participants (a differences in microstructural characteristics of NAWM and WMH per cerebral lobe; and (b the association of macrostructural (WMH volume and microstructural characteristics (within NAWM and WMH separately of each lobe with measures of executive function and processing speed. Multi-modal imaging (i.e., T1, DTI, and FLAIR was used to assess WM properties. The Stroop and the Trail Making Test were used to measure inhibition, task-switching (both components of executive function, and processing speed. We observed that age was associated with deterioration of white matter microstructure of the NAWM, most notably in the frontal lobe. Older participants had larger WMH volumes and lowest fractional anisotropy values within WMH were found in the frontal lobe. Task-switching was associated with cerebral NAWM volume and NAWM volume of all lobes. Processing speed was associated with total NAWM volume, and microstructural properties of parietal NAWM, the parietal WMH, and the temporal NAWM. Task-switching was related to microstructural properties of WMH of the frontal lobe and WMH volume of the parietal lobe. Our results confirm that executive functioning and processing speed are uniquely associated with macro- and microstructural properties of NAWM and WMH. We further demonstrate for the first time that these relationships differ by lobar region. This warrants the consideration of these distinct WM indices when investigating cognitive function.

  7. Is multidetector CT-based bone mineral density and quantitative bone microstructure assessment at the spine still feasible using ultra-low tube current and sparse sampling?

    Energy Technology Data Exchange (ETDEWEB)

    Mei, Kai; Kopp, Felix K.; Schwaiger, Benedikt J.; Gersing, Alexandra S.; Sauter, Andreas; Muenzel, Daniela; Rummeny, Ernst J. [Klinikum rechts der Isar, Technische Universitaet Muenchen, Department of Diagnostic and Interventional Radiology, Munich (Germany); Bippus, Rolf [Research Laboratories, Philips GmbH Innovative Technologies, Hamburg (Germany); Koehler, Thomas [Research Laboratories, Philips GmbH Innovative Technologies, Hamburg (Germany); Technische Universitaet Muenchen, TUM Institute for Advanced Studies, Garching (Germany); Fehringer, Andreas [Technische Universitaet Muenchen, Lehrstuhl fuer Biomedizinische Physik, Garching (Germany); Pfeiffer, Franz [Klinikum rechts der Isar, Technische Universitaet Muenchen, Department of Diagnostic and Interventional Radiology, Munich (Germany); Technische Universitaet Muenchen, TUM Institute for Advanced Studies, Garching (Germany); Technische Universitaet Muenchen, Lehrstuhl fuer Biomedizinische Physik, Garching (Germany); Kirschke, Jan S. [Klinikum rechts der Isar, Technische Universitaet Muenchen, Section of Diagnostic and Interventional Neuroradiology, Munich (Germany); Noel, Peter B. [Klinikum rechts der Isar, Technische Universitaet Muenchen, Department of Diagnostic and Interventional Radiology, Munich (Germany); Technische Universitaet Muenchen, Lehrstuhl fuer Biomedizinische Physik, Garching (Germany); Baum, Thomas [Klinikum rechts der Isar, Technische Universitaet Muenchen, Department of Diagnostic and Interventional Radiology, Munich (Germany); Klinikum rechts der Isar, Technische Universitaet Muenchen, Section of Diagnostic and Interventional Neuroradiology, Munich (Germany)

    2017-12-15

    Osteoporosis diagnosis using multidetector CT (MDCT) is limited to relatively high radiation exposure. We investigated the effect of simulated ultra-low-dose protocols on in-vivo bone mineral density (BMD) and quantitative trabecular bone assessment. Institutional review board approval was obtained. Twelve subjects with osteoporotic vertebral fractures and 12 age- and gender-matched controls undergoing routine thoracic and abdominal MDCT were included (average effective dose: 10 mSv). Ultra-low radiation examinations were achieved by simulating lower tube currents and sparse samplings at 50%, 25% and 10% of the original dose. BMD and trabecular bone parameters were extracted in T10-L5. Except for BMD measurements in sparse sampling data, absolute values of all parameters derived from ultra-low-dose data were significantly different from those derived from original dose images (p<0.05). BMD, apparent bone fraction and trabecular thickness were still consistently lower in subjects with than in those without fractures (p<0.05). In ultra-low-dose scans, BMD and microstructure parameters were able to differentiate subjects with and without vertebral fractures, suggesting osteoporosis diagnosis is feasible. However, absolute values differed from original values. BMD from sparse sampling appeared to be more robust. This dose-dependency of parameters should be considered for future clinical use. (orig.)

  8. Is multidetector CT-based bone mineral density and quantitative bone microstructure assessment at the spine still feasible using ultra-low tube current and sparse sampling?

    International Nuclear Information System (INIS)

    Mei, Kai; Kopp, Felix K.; Schwaiger, Benedikt J.; Gersing, Alexandra S.; Sauter, Andreas; Muenzel, Daniela; Rummeny, Ernst J.; Bippus, Rolf; Koehler, Thomas; Fehringer, Andreas; Pfeiffer, Franz; Kirschke, Jan S.; Noel, Peter B.; Baum, Thomas

    2017-01-01

    Osteoporosis diagnosis using multidetector CT (MDCT) is limited to relatively high radiation exposure. We investigated the effect of simulated ultra-low-dose protocols on in-vivo bone mineral density (BMD) and quantitative trabecular bone assessment. Institutional review board approval was obtained. Twelve subjects with osteoporotic vertebral fractures and 12 age- and gender-matched controls undergoing routine thoracic and abdominal MDCT were included (average effective dose: 10 mSv). Ultra-low radiation examinations were achieved by simulating lower tube currents and sparse samplings at 50%, 25% and 10% of the original dose. BMD and trabecular bone parameters were extracted in T10-L5. Except for BMD measurements in sparse sampling data, absolute values of all parameters derived from ultra-low-dose data were significantly different from those derived from original dose images (p<0.05). BMD, apparent bone fraction and trabecular thickness were still consistently lower in subjects with than in those without fractures (p<0.05). In ultra-low-dose scans, BMD and microstructure parameters were able to differentiate subjects with and without vertebral fractures, suggesting osteoporosis diagnosis is feasible. However, absolute values differed from original values. BMD from sparse sampling appeared to be more robust. This dose-dependency of parameters should be considered for future clinical use. (orig.)

  9. Trabecular bone microstructure is impaired in the proximal femur of human immunodeficiency virus-infected men with normal bone mineral density.

    Science.gov (United States)

    Kazakia, Galateia J; Carballido-Gamio, Julio; Lai, Andrew; Nardo, Lorenzo; Facchetti, Luca; Pasco, Courtney; Zhang, Chiyuan A; Han, Misung; Parrott, Amanda Hutton; Tien, Phyllis; Krug, Roland

    2018-02-01

    There is evidence that human immunodeficiency virus (HIV) infection and antiretroviral therapy (ART) are independent risk factors for osteoporosis and fracture which is not solely explained by changes in bone mineral density. Thus, we hypothesized that the assessment of trabecular microstructure might play an important role for bone quality in this population and might explain the increased fracture risk. In this study, we have assessed bone microstructure in the proximal femur using high-resolution magnetic resonance imaging (MRI) as well as in the extremities using high resolution peripheral quantitative computed tomography (HR-pQCT) in HIV-infected men and healthy controls and compared these findings to those based on areal bone mineral density (aBMD) derived from dual X-ray absorptiometry (DXA) which is the standard clinical parameter for the diagnosis of osteoporosis. Eight HIV-infected men and 11 healthy age-matched controls were recruited and informed consent was obtained before each scan. High-resolution MRI of the proximal femur was performed using fully balanced steady state free precession (bSSFP) on a 3T system. Three volumes of interest at corresponding anatomic locations across all subjects were defined based on registrations of a common template. Four MR-based trabecular microstructural parameters were analyzed at each region: fuzzy bone volume fraction (f-BVF), trabecular number (Tb.N), thickness (Tb.Th), and spacing (Tb.Sp). In addition, the distal radius and distal tibia were imaged with HR-pQCT. Four HR-pQCT-based microstructural parameters were analyzed: trabecular bone volume fraction (BV/TV), Tb.N, Tb.Th, and Tb.Sp. Total hip and spine aBMD were determined from DXA. Microstructural bone parameters derived from MRI at the proximal femur and from HR-pQCT at the distal tibia showed significantly lower bone quality in HIV-infected patients compared to healthy controls. In contrast, DXA aBMD data showed no significant differences between HIV

  10. Online traffic flow model applying dynamic flow-density relation

    International Nuclear Information System (INIS)

    Kim, Y.

    2002-01-01

    This dissertation describes a new approach of the online traffic flow modelling based on the hydrodynamic traffic flow model and an online process to adapt the flow-density relation dynamically. The new modelling approach was tested based on the real traffic situations in various homogeneous motorway sections and a motorway section with ramps and gave encouraging simulation results. This work is composed of two parts: first the analysis of traffic flow characteristics and second the development of a new online traffic flow model applying these characteristics. For homogeneous motorway sections traffic flow is classified into six different traffic states with different characteristics. Delimitation criteria were developed to separate these states. The hysteresis phenomena were analysed during the transitions between these traffic states. The traffic states and the transitions are represented on a states diagram with the flow axis and the density axis. For motorway sections with ramps the complicated traffic flow is simplified and classified into three traffic states depending on the propagation of congestion. The traffic states are represented on a phase diagram with the upstream demand axis and the interaction strength axis which was defined in this research. The states diagram and the phase diagram provide a basis for the development of the dynamic flow-density relation. The first-order hydrodynamic traffic flow model was programmed according to the cell-transmission scheme extended by the modification of flow dependent sending/receiving functions, the classification of cells and the determination strategy for the flow-density relation in the cells. The unreasonable results of macroscopic traffic flow models, which may occur in the first and last cells in certain conditions are alleviated by applying buffer cells between the traffic data and the model. The sending/receiving functions of the cells are determined dynamically based on the classification of the

  11. Relations among several nuclear and electronic density functional reactivity indexes

    Science.gov (United States)

    Torrent-Sucarrat, Miquel; Luis, Josep M.; Duran, Miquel; Toro-Labbé, Alejandro; Solà, Miquel

    2003-11-01

    An expansion of the energy functional in terms of the total number of electrons and the normal coordinates within the canonical ensemble is presented. A comparison of this expansion with the expansion of the energy in terms of the total number of electrons and the external potential leads to new relations among common density functional reactivity descriptors. The formulas obtained provide explicit links between important quantities related to the chemical reactivity of a system. In particular, the relation between the nuclear and the electronic Fukui functions is recovered. The connection between the derivatives of the electronic energy and the nuclear repulsion energy with respect to the external potential offers a proof for the "Quantum Chemical le Chatelier Principle." Finally, the nuclear linear response function is defined and the relation of this function with the electronic linear response function is given.

  12. Alterations of bone density, microstructure, and strength of the distal radius in male patients with rheumatoid arthritis: a case-control study with HR-pQCT.

    Science.gov (United States)

    Zhu, Tracy Y; Griffith, James F; Qin, Ling; Hung, Vivian W; Fong, Tsz-Ning; Au, Sze-Ki; Li, Martin; Lam, Yvonne Yi-On; Wong, Chun-Kwok; Kwok, Anthony W; Leung, Ping-Chung; Li, Edmund K; Tam, Lai-Shan

    2014-09-01

    In this cross-sectional study, we investigated volumetric bone mineral density (vBMD), bone microstructure, and biomechanical competence of the distal radius in male patients with rheumatoid arthritis (RA). The study cohort comprised 50 male RA patients of average age of 61.1 years and 50 age-matched healthy males. Areal BMD (aBMD) of the hip, lumbar spine, and distal radius was measured by dual-energy X-ray absorptiometry. High-resolution peripheral quantitative computed tomography (HR-pQCT) of the distal radius provided measures of cortical and trabecular vBMD, microstructure, and biomechanical indices. aBMD of the hip but not the lumbar spine or ultradistal radius was significantly lower in RA patients than controls after adjustment for body weight. Total, cortical, and trabecular vBMD at the distal radius were, on average, -3.9% to -23.2% significantly lower in RA patients, and these differences were not affected by adjustment for body weight, testosterone level, or aBMD at the ultradistal radius. Trabecular microstructure indices were, on average, -8.1% (trabecular number) to 28.7% (trabecular network inhomogeneity) significantly inferior, whereas cortical pore volume and cortical porosity index were, on average, 80.3% and 63.9%, respectively, significantly higher in RA patients. RA patients also had significantly lower whole-bone stiffness, modulus, and failure load, with lower and more unevenly distributed cortical and trabecular stress. Density and microstructure indices significantly correlated with disease activity, severity, and levels of pro-inflammatory cytokines (interleukin [IL] 12p70, tumor necrosis factor, IL-6 and IL-1β). Ten RA patients had focal periosteal bone apposition most prominent at the ulnovolar aspect of the distal radius. These patients had shorter disease duration and significantly higher cortical porosity. In conclusion, HR-pQCT reveals significant alterations of bone density, microstructure, and strength of the distal radius in

  13. Evaluation of alcohol outlet density and its relation with violence

    Directory of Open Access Journals (Sweden)

    Laranjeira Ronaldo

    2002-01-01

    Full Text Available OBJECTIVES: The current study set out to investigate alcohol availability in a densely populated, residential area of suburban São Paulo associated with high levels of social deprivation and violence. Gun-related deaths and a heavy concentration of alcohol outlets are notable features of the area surveyed. Given the strong evidence for a link between alcohol availability and a number of alcohol-related problems, including violent crime, measures designed to reduce accessibility have become a favored choice for alcohol prevention programs in recent years. METHODS: The interviewers were 24 residents of the area who were trained for the study. It was selected an area of nineteen streets, covering a total distance of 3.7 km. A profile of each alcohol outlet available on the area was recorded. RESULTS: One hundred and seven alcohol outlets were recorded. The number of other properties in the same area was counted at 1,202. Two measures of outlet density may thus be calculated: the number of outlets per kilometer of roadway (29 outlets/km; and the proportion of all properties that sold alcohol (1 in 12. CONCLUSIONS: The results of this study is compared with others which are mainly from developed countries and shown that the area studied have the highest density of alcohol outlet density ever recorded in the medical literature. The implication of this data related to the violence of the region is discussed. By generating a profile of alcohol sales and selling points, it was hoped to gain a better understanding of alcohol access issues within the sample area. Future alcohol prevention policy would be well served by such knowledge.

  14. Natural analogue and microstructural studies in relation to radionuclide retardation by rock matrix diffusion in granite

    International Nuclear Information System (INIS)

    Montoto, M.; Rodriguez Rey, A.; Ruiz de Argandona, V.G.; Calleja, L.; Menendez, B.

    1992-01-01

    The possibility that radionuclide retardation by rock matrix diffusion will be limited in granitic rocks by geological factors is studied, as well as the possibility that diffusion will be confined to a narrow zone from water-conducting fractures. Petrophysical measurements, uranium series and geochemical analyses in the rock adjacent to fractures, have been performed to establish the extent of fracture-related microstructural changes that might influence the potential for diffusion and whether or not there is any record of diffusion of uranium, its daughters, or other elements. The results obtained from El Berrocal (Spain), Stripa (Sweden) and White-shell (Canada) granites, suggest that: (a) there is a zone adjacent to the fractures (generally less than 100 mm) where microstructural changes and enhanced uranium mobility exist; (b) the evidence for diffusion having taken place in the rock is confined largely to this zone. So, it appears that diffusivity determinations on rock collected away from the influence of fractures will not give representative data for diffusion modelling, in addition to the effect of distressing after removing rocks from depth. It is suggested that diffusion will be of limited effectiveness as a retardation mechanism in many granitic rocks, particularly in water movement confined to narrow channels where access by nuclides to the fracture walls is restricted. 51 refs., 56 figs., 9 tabs., 9 appendices

  15. Interfacial Tension and Surface Pressure of High Density Lipoprotein, Low Density Lipoprotein, and Related Lipid Droplets

    DEFF Research Database (Denmark)

    Ollila, O. H. S.; Lamberg, A.; Lehtivaara, M.

    2012-01-01

    ) are essentially lipid droplets surrounded by specific proteins, their main function being to transport cholesterol. Interfacial tension and surface pressure of these particles are of great interest because they are related to the shape and the stability of the droplets and to protein adsorption at the interface....... Here we use coarse-grained molecular-dynamics simulations to consider a number of related issues by calculating the interfacial tension in protein-free lipid droplets, and in HDL and LDL particles mimicking physiological conditions. First, our results suggest that the curvature dependence......Lipid droplets play a central role in energy storage and metabolism on a cellular scale. Their core is comprised of hydrophobic lipids covered by a surface region consisting of amphiphilic lipids and proteins. For example, high and low density lipoproteins (HDL and LDL, respectively...

  16. Effects of magnetic flux densities on microstructure evolution and magnetic properties of molecular-beam-vapor-deposited nanocrystalline Fe_3_0Ni_7_0 thin films

    International Nuclear Information System (INIS)

    Cao, Yongze; Wang, Qiang; Li, Guojian; Ma, Yonghui; Du, Jiaojiao; He, Jicheng

    2015-01-01

    Nanocrystalline Fe_3_0Ni_7_0 (in atomic %) thin films were prepared by molecular-beam-vapor deposition in magnetic fields with different magnetic flux densities. The microstructure evolution of these thin films was studied by atomic force microscopy, transmission electron microscopy, and high resolution transmission electron microscopy; the soft magnetic properties were examined by vibrating sample magnetometer at room temperature. The results show that all our Fe_3_0Ni_7_0 thin films feature an fcc single-phase structure. With increasing magnetic flux density, surface roughness, average particle size and grain size of the thin films decreased, and the short-range ordered clusters (embryos) of thin films increased. Additionally, the magnetic anisotropy in the in-plane and the coercive forces of the thin films gradually reduced with increasing magnetic flux density. - Highlights: • With increasing magnetic flux density, average particle size of films decreased. • With increasing magnetic flux density, surface roughness of thin films decreased. • With increasing magnetic flux density, short-range ordered clusters increased. • With increasing magnetic flux density, the coercive forces of thin films reduced. • With increasing magnetic flux density, soft magnetic properties are improved.

  17. Unique Microstructural Changes in the Brain Associated with Urological Chronic Pelvic Pain Syndrome (UCPPS Revealed by Diffusion Tensor MRI, Super-Resolution Track Density Imaging, and Statistical Parameter Mapping: A MAPP Network Neuroimaging Study.

    Directory of Open Access Journals (Sweden)

    Davis Woodworth

    Full Text Available Studies have suggested chronic pain syndromes are associated with neural reorganization in specific regions associated with perception, processing, and integration of pain. Urological chronic pelvic pain syndrome (UCPPS represents a collection of pain syndromes characterized by pelvic pain, namely Chronic Prostatitis/Chronic Pelvic Pain Syndrome (CP/CPPS and Interstitial Cystitis/Painful Bladder Syndrome (IC/PBS, that are both poorly understood in their pathophysiology, and treated ineffectively. We hypothesized patients with UCPPS may have microstructural differences in the brain compared with healthy control subjects (HCs, as well as patients with irritable bowel syndrome (IBS, a common gastrointestinal pain disorder. In the current study we performed population-based voxel-wise DTI and super-resolution track density imaging (TDI in a large, two-center sample of phenotyped patients from the multicenter cohort with UCPPS (N = 45, IBS (N = 39, and HCs (N = 56 as part of the MAPP Research Network. Compared with HCs, UCPPS patients had lower fractional anisotropy (FA, lower generalized anisotropy (GA, lower track density, and higher mean diffusivity (MD in brain regions commonly associated with perception and integration of pain information. Results also showed significant differences in specific anatomical regions in UCPPS patients when compared with IBS patients, consistent with microstructural alterations specific to UCPPS. While IBS patients showed clear sex related differences in FA, MD, GA, and track density consistent with previous reports, few such differences were observed in UCPPS patients. Heat maps illustrating the correlation between specific regions of interest and various pain and urinary symptom scores showed clustering of significant associations along the cortico-basal ganglia-thalamic-cortical loop associated with pain integration, modulation, and perception. Together, results suggest patients with UCPPS have extensive

  18. Annihilation Radiation Gauge for Relative Density and Multiphase Fluid Monitoring

    Directory of Open Access Journals (Sweden)

    Vidal A.

    2014-03-01

    Full Text Available The knowledge of the multi-phase flow parameters are important for the petroleum industry, specifically during the transport in pipelines and network related to exploitation’s wells. Crude oil flow is studied by Monte Carlo simulation and experimentally to determine transient liquid phase in a laboratory system. Relative density and fluid phase time variation is monitored employing a fast nuclear data acquisition setup that includes two large volume BaF2 scintillator detectors coupled to an electronic chain and data display in a LabView® environment. Fluid parameters are determined by the difference in count rate of coincidence pulses. The operational characteristics of the equipment indicate that 2 % deviation in the CCR corresponds to a variation, on average, of 20 % in the fraction of liquid of the multiphase fluid.

  19. Positron probing of electron momentum density in GaAs-AlAs superlattices and related materials

    International Nuclear Information System (INIS)

    Arutyunov, N.Y.; Sekkal, N.

    2008-08-01

    The band structure calculations based on the method proposed by Jaros et al. (Phys. Rev. B 31, 1205 (1985)) have been performed for the defect-free GaAs-AlAs superlattice and related AlAs and GaAs single crystals; the electron-positron momentum density distributions have been computed and analyzed. The results of calculations are in good agreement with the experimental data obtained ad hoc for GaAs and AlAs bulk materials by measuring the angular correlation of the annihilation radiation (ACAR). Small (but marked) features of the electron-positron momentum density of the valence band have been revealed both for constituent materials and GaAs-AlAs superlattice. The delocalization of positron in 'perfect' defect-'free' AlAs and GaAs single crystals to be observed experimentally is borne out by the results of pseudo-potential band calculations performed on the basis of method proposed by Sekkal et al. (Superlattices and Microstructures, 33, 63 (2003)). The prediction of the possibility of a certain confinement of positron in the interstitial area of GaAs- AlAs superlattice is confirmed by the agreement between the results of calculations and relevant experimental data obtained for GaAs and AlAs single crystals. No considerable effect of the enhancement of the annihilation rate (due to electron-positron interaction) upon the electron-positron momentum density distribution both in the superlattice and its constituent bulk materials has been found. The results of ACAR measurements and calculations performed suggest that a tangible improvement of the sensitivity of existing positron annihilation techniques is necessary for studying details of the electron-positron momentum density distributions in defect-'free' superlattices to be created on the basis of the diamond-like semiconductors possessing close values of the electron momentum densities. On the contrary, the positron-sensitive vacancy-type defects of various types in the superlattice may become a source of the

  20. 54 relative density and distribution of tantalus monkey

    African Journals Online (AJOL)

    Tersor

    RANGES OF SAMBISA GAME RESERVE. M. Modu*, A. A. ... density and he found a negative relationship with minimum density. .... analysis. A comprehensive computer software .... a large effect on the abundance and ranging ecology of ...

  1. Relation between microstructure and thermal conductivity in aluminium nitride substrates; Relations entre la microstructure et la conductivite thermique dans les substrats de nitrure d`aluminium

    Energy Technology Data Exchange (ETDEWEB)

    Jarrige, J.; Lecompte, J.P.; Seck, O. [Faculte des Sciences (CNRS), 87 - Limoges (France). Laboratoire de Materiaux Ceramiques et Traitements de Surface

    1996-12-31

    Sintered aluminium nitride is a promising ceramic substrate for future power electronics applications. This ceramic is characterized by a high thermal conductivity (100 to 200 W/m.K) which depends on two main factors: the oxygen content of the AlN powder used for the sintering process and the microstructure of the sintered material. The oxygen content changes with sintering additions. For instance, boron nitride allows the diffusion of oxygen from the nitride grains to the grain joints. With a complement of yttrium oxide in the liquid phase, the BN/Y{sub 2}O{sub 3} couple allows to increase the conductivity to 190 W/m.K with a reduction of the oxygen content. The second part of the study concerns the microstructure of sintered materials. A control of conductivity can be obtained using an adjustment of the sintering cycles. Only two types of microstructure, the secondary phase dispersed in the AlN matrix and the secondary phase that concentrates around triple junctions, allow a better contact between nitride grains and thus higher conductivities of 210 W/m.K. (J.S.) 6 refs.

  2. White Matter Microstructure of the Human Mirror Neuron System Is Related to Symptom Severity in Adults with Autism

    Science.gov (United States)

    Fründt, Odette; Schulz, Robert; Schöttle, Daniel; Cheng, Bastian; Thomalla, Götz; Braaß, Hanna; Ganos, Christos; David, Nicole; Peiker, Ina; Engel, Andreas K.; Bäumer, Tobias; Münchau, Alexander

    2018-01-01

    Mirror neuron system (MNS) dysfunctions might underlie deficits in autism spectrum disorders (ASD). Diffusion tensor imaging based probabilistic tractography was conducted in 15 adult ASD patients and 13 matched, healthy controls. Fractional anisotropy (FA) was quantified to assess group differences in tract-related white matter microstructure of…

  3. ICRF power limitation relation to density limit in ASDEX

    International Nuclear Information System (INIS)

    Ryter, F.

    1992-01-01

    Launching high ICRF power into ASDEX plasmas required good antenna-plasma coupling. This could be achieved by sufficient electron density in front of the antennas i.e. small antenna-plasma distance (1-2 cm) and moderate to high line-averaged electron density compared to the density window in ASDEX. These are conditions eventually close to the density limit. ICRF heated discharges terminated by plasma disruptions caused by the RF pulse limited the maximum RF power which can be injected into the plasma. The disruptions occurring in these cases have clear phenomenological similarities with those observed in density limit discharges. We show in this paper that the ICRF-power limitation by plasma disruptions in ASDEX was due to reaching the density limit. (orig.)

  4. ICRF power limitation relation to density limit in ASDEX

    International Nuclear Information System (INIS)

    Ryter, F.

    1992-01-01

    Launching high ICRF power into ASDEX plasmas required good antenna-plasma coupling. This could be achieved by sufficient electron density in front of the antennas i.e. small antenna-plasma distance (1-2 cm) and moderate to high line-averaged electron density compared to the density window in ASDEX. These are conditions eventually close to the density limit. ICRF heated discharges terminated by plasma disruptions caused by the RF pulse limited the maximum RF power which can be injected into the plasma. The disruptions occurring in these cases have clear phenomenological similarities with those observed in density limit discharges. We show in this paper that the ICRF-power limitation by plasma disruptions in ASDEX was due to reaching the density limit. (author) 3 refs., 3 figs

  5. Normal Bone Microstructure and Density But Worse Physical Function in Older Women Treated with Selective Serotonin Reuptake Inhibitors, a Cross-Sectional Population-Based Study.

    Science.gov (United States)

    Larsson, Berit; Mellström, Dan; Johansson, Lisa; Nilsson, Anna G; Lorentzon, Mattias; Sundh, Daniel

    2018-05-05

    Depression in the elderly is today often treated with selective serotonin reuptake inhibitors (SSRIs) because of their favorable adverse effect profile. However, treatment with SSRIs is associated with increased risk of fractures. Whether this increased risk depends on reduced bone strength or increased fall risk due to reduced physical function is not certain. The aim was therefore to investigate if treatment with SSRIs is associated with impaired bone microstructure, bone density, or physical function in older women. From an ongoing population-based study, 1057 women (77.7 ± 1.5 years) were included. Validated questionnaires were used to assess information regarding medical history, medications, smoking, mental and physical health, and physical activity. Physical function was measured using clinically used tests: timed up and go, walking speed, grip strength, chair stand test, and one leg standing. Bone mineral density (BMD) was measured at the hip and spine with dual-energy X-ray absorptiometry (Hologic Discovery A). Bone geometry and microstructure were measured at the ultradistal and distal (14%) site of radius and tibia using high-resolution peripheral quantitative computed tomography (HR-pQCT; XtremeCT). Treatment with SSRIs was associated with higher BMD at the femoral neck, total hip, and lumbar spine, whereas no associations were found for any HR-pQCT-derived measurements. The use of SSRIs was associated with lower grip strength, walking speed, and fewer chair stand rises. These associations were valid also after adjustments for known risk factors for falls. Treatment with SSRIs was, independently of covariates, associated with worse physical function without any signs of inferior bone geometry and microstructure.

  6. Relative density: the key to stocking assessment in regional analysis—a forest survey viewpoint.

    Science.gov (United States)

    Colin D. MacLean

    1979-01-01

    Relative density is a measure of tree crowding compared to a reference level such as normal density. This stand attribute, when compared to management standards, indicates adequacy of stocking. The Pacific Coast Forest Survey Unit assesses the relative density of each stand sampled by summing the individual density contributions of each tree tallied, thus quantifying...

  7. Differences observed in the surface morphology and microstructure of Ni-Fe-Cu ternary thin films electrochemically deposited at low and high applied current densities

    International Nuclear Information System (INIS)

    Sarac, U; Kaya, M; Baykul, M C

    2016-01-01

    In this research, nanocrystalline Ni-Fe-Cu ternary thin films using electrochemical deposition technique were produced at low and high applied current densities onto Indium Tin Oxide (ITO) coated conducting glass substrates. Change of surface morphology and microstructural properties of the films were investigated. Energy dispersive X-ray spectroscopy (EDX) measurements showed that the Ni-Fe-Cu ternary thin films exhibit anomalous codeposition behaviour during the electrochemical deposition process. From the X-ray diffraction (XRD) analyses, it was revealed that there are two segregated phases such as Cu- rich and Ni-rich within the films. The crystallographic structure of the films was face-centered cubic (FCC). It was also observed that the film has lower lattice micro-strain and higher texture degree at high applied current density. Scanning electron microscopy (SEM) studies revealed that the films have rounded shape particles on the base part and cauliflower-like structures on the upper part. The film electrodeposited at high current density had considerably smaller rounded shape particles and cauliflower-like structures. From the atomic force microscopy (AFM) analyses, it was shown that the film deposited at high current density has smaller particle size and surface roughness than the film grown at low current density. (paper)

  8. Relation between the microstructure and technological properties of porcelain stoneware. A review

    Directory of Open Access Journals (Sweden)

    Romero, M.

    2015-12-01

    Full Text Available Porcelain stoneware is a strongly sintered ceramic material fabricated from ball clays-quartz-feldspar mixtures. Porcelain stoneware is characterized by its excellent technical and functional properties (low water absorption, high mechanical properties, resistant to chemical substances and cleaning agents, aesthetic possibilities …. These characteristic and technical features make that among the different types of ceramic tile, porcelain stoneware is the ceramic product that in the last years has best withstood the economic crisis in the construction sector. These properties are related to the microstructure of porcelain stoneware, which is a grain and bond type with large particles of filler (quartz, mullite crystals, a silica-rich amorphous phase and porosity. The understanding of the relationship between the microstructure and the properties of porcelain stoneware is hardly important for the development and design of these materials whose tendency is the manufacture of thinner tiles with higher dimensions but must continue to comply the specific technical requirements.El gres porcelánico es un material sinterizado fabricado a partir de una mezcla de arcillas, cuarzo y feldespato. Tecnológicamente, el gres porcelánico se caracteriza por sus excelentes características técnicas y funcionales (baja absorción de agua, buenas propiedades mecánicas, resistente a substancias químicas, posibilidades estéticas…. Estas cualidades han propiciado que, entre los diferentes tipos de baldosa cerámica, es el gres porcelánico el producto que mejor ha resistido la crisis económica sufrida por el Sector de la Construcción. Las propiedades tecnológicas están relacionadas con su microestructura, compuesta de partículas de cuarzo, cristales de mullita, fase amorfa y porosidad. El conocimiento de la relación entre la microestructura y las propiedades tecnológicas del gres porcelánico es de gran importancia para avanzar en el diseño y

  9. Ultrasonic delineation of aortic microstructure: The relative contribution of elastin and collagen to aortic elasticity

    Science.gov (United States)

    Marsh, Jon N.; Takiuchi, Shin; Lin, Shiow Jiuan; Lanza, Gregory M.; Wickline, Samuel A.

    2004-05-01

    Aortic elasticity is an important factor in hemodynamic health, and compromised aortic compliance affects not only arterial dynamics but also myocardial function. A variety of pathologic processes (e.g., diabetes, Marfan's syndrome, hypertension) can affect aortic elasticity by altering the microstructure and composition of the elastin and collagen fiber networks within the tunica media. Ultrasound tissue characterization techniques can be used to obtain direct measurements of the stiffness coefficients of aorta by measurement of the speed of sound in specific directions. In this study we sought to define the contributions of elastin and collagen to the mechanical properties of aortic media by measuring the magnitude and directional dependence of the speed of sound before and after selective isolation of either the collagen or elastin fiber matrix. Formalin-fixed porcine aortas were sectioned for insonification in the circumferential, longitudinal, or radial direction and examined using high-frequency (50 MHz) ultrasound microscopy. Isolation of the collagen or elastin fiber matrices was accomplished through treatment with NaOH or formic acid, respectively. The results suggest that elastin is the primary contributor to aortic medial stiffness in the unloaded state, and that there is relatively little anisotropy in the speed of sound or stiffness in the aortic wall.

  10. The Impact of the Prior Density on a Minimum Relative Entropy Density: A Case Study with SPX Option Data

    Directory of Open Access Journals (Sweden)

    Cassio Neri

    2014-05-01

    Full Text Available We study the problem of finding probability densities that match given European call option prices. To allow prior information about such a density to be taken into account, we generalise the algorithm presented in Neri and Schneider (Appl. Math. Finance 2013 to find the maximum entropy density of an asset price to the relative entropy case. This is applied to study the impact of the choice of prior density in two market scenarios. In the first scenario, call option prices are prescribed at only a small number of strikes, and we see that the choice of prior, or indeed its omission, yields notably different densities. The second scenario is given by CBOE option price data for S&P500 index options at a large number of strikes. Prior information is now considered to be given by calibrated Heston, Schöbel–Zhu or Variance Gamma models. We find that the resulting digital option prices are essentially the same as those given by the (non-relative Buchen–Kelly density itself. In other words, in a sufficiently liquid market, the influence of the prior density seems to vanish almost completely. Finally, we study variance swaps and derive a simple formula relating the fair variance swap rate to entropy. Then we show, again, that the prior loses its influence on the fair variance swap rate as the number of strikes increases.

  11. Microstructure of bentonite in relation to its physical properties within nuclear waste repositories

    International Nuclear Information System (INIS)

    Laine, E.

    1998-01-01

    High-level nuclear waste in Finland is planned to be placed in bedrock at a depth of several hundred metres. The spent fuel containers in boreholes drilled in the floors of deposition tunnels will be surrounded by bentonite blocks. The upper parts of the tunnels will be filled with mixture of bentonite and crushed rock. The behaviour of the bentonite around the containers during several years after deposition of nuclear waste should be predicted. In the present report, a short literature study of the microstructure of bentonite is presented. The report concentrates on bentonite MX-80. The use of stochastic imaging of microstructure was tested by using the Boolean simulation. Using stochastic imaging, the effect of changes of bentonite microstructure on its physical properties can be evaluated and predicted. (orig.)

  12. An expression relating breaking stress and density of trabecular bone

    DEFF Research Database (Denmark)

    Rajapakse, C.S.; Thomsen, J.S.; Ortiz, J.S.E.

    2004-01-01

    Bone mineral density (BMD) is the principal diagnostic tool used in clinical settings to diagnose and monitor osteoporosis. Experimental studies on ex vivo bone samples from multiple skeletal locations have been used to propose that their breaking stress bears a power-law relationship to volumetric...

  13. Microstructural analyses and critical current densities in the high-Tc superconductor system ReBa2Cu3OX, with RE = Y, Sm, Eu, Gd, Dy, Ho

    International Nuclear Information System (INIS)

    Schindler, G.; Seebacher, B.

    1989-01-01

    The authors report on investigations into the impact of the rare earths (RE) as given in the title on the ceramic microstructure and the critical current density j c in the superconductor system REBa 2 Cu 3 O x . With RE = Sm, Eu, or Gd, the material is homogeneous in phase and crystallizes in platelets with maximum sizes of up to 350 μm. Material with RE = Y, Dy, or Ho exhibits grain sizes up to 500 μm, and a low amount of phase inhomogeneities. The critical currents measured are between 25 Acm -2 and 290 Acm -2 at 77 K, without external field. The highest values are found in systems with RE = Eu or Gd. (orig.) [de

  14. Determination of Basic Structure-Property Relations for Processing and Modeling in Advanced Nuclear Fuel: Microstructure Evolution and Mechanical Properties

    International Nuclear Information System (INIS)

    Wheeler, Kirk; Parra, Manuel; Peralta, Pedro

    2009-01-01

    The project objective is to study structure-property relations in solid solutions of nitrides and oxides with surrogate elements to simulate the behavior of fuels of inert matrix fuels of interest to the Advanced Fuel Cycle Initiative (AFCI), with emphasis in zirconium-based materials. Work with actual fuels will be carried out in parallel in collaboration with Los Alamos National Laboratory (LANL). Three key aspects will be explored: microstructure characterization through measurement of global texture evolution and local crystallographic variations using Electron Backscattering Diffraction (EBSD); determination of mechanical properties, including fracture toughness, quasi-static compression strength, and hardness, as functions of load and temperature, and, finally, development of structure-property relations to describe mechanical behavior of the fuels based on experimental data. Materials tested will be characterized to identify the mechanisms of deformation and fracture and their relationship to microstructure and its evolution. New aspects of this research are the inclusion of crystallographic information into the evaluation of fuel performance and the incorporation of statistical variations of microstructural variables into simplified models of mechanical behavior of fuels that account explicitly for these variations. The work is expected to provide insight into processing conditions leading to better fuel performance and structural reliability during manufacturing and service, as well as providing a simplified testing model for future fuel production

  15. Microstructural and crystallographic imperfections of MgB2 superconducting wire and their correlation with the critical current density

    Science.gov (United States)

    Shahabuddin, Mohammed; Alzayed, Nasser S.; Oh, Sangjun; Choi, Seyong; Maeda, Minoru; Hata, Satoshi; Shimada, Yusuke; Hossain, Md Shahriar Al; Kim, Jung Ho

    2014-01-01

    A comprehensive study of the effects of structural imperfections in MgB2 superconducting wire has been conducted. As the sintering temperature becomes lower, the structural imperfections of the MgB2 material are increased, as reflected by detailed X-ray refinement and the normal state resistivity. The crystalline imperfections, caused by lattice disorder, directly affect the impurity scattering between the π and σ bands of MgB2, resulting in a larger upper critical field. In addition, low sintering temperature keeps the grain size small, which leads to a strong enhancement of pinning, and thereby, enhanced critical current density. Owing to both the impurity scattering and the grain boundary pinning, the critical current density, irreversibility field, and upper critical field are enhanced. Residual voids or porosities obviously remain in the MgB2, however, even at low sintering temperature, and thus block current transport paths.

  16. Microstructural and crystallographic imperfections of MgB{sub 2} superconducting wire and their correlation with the critical current density

    Energy Technology Data Exchange (ETDEWEB)

    Shahabuddin, Mohammed; Alzayed, Nasser S. [Department of Physics and Astronomy, College of Science, P. O. Box 2455, King Saud University, Riyadh 11451 (Saudi Arabia); Oh, Sangjun [Materials Research Team, National Fusion Research Institute, Yueeong, Daejeon 305-333 (Korea, Republic of); Choi, Seyong [Busan Center, Korea Basic Science Institute, Geumjeong, Busan 609-735 (Korea, Republic of); Maeda, Minoru [Department of Physics, College of Science and Technology, Nihon University, 1-8 Kanda-Surugadai, Chiyoda-ku, Tokyo 101-8308 (Japan); Hata, Satoshi; Shimada, Yusuke [Interdisciplinary Graduate School of Engineering Sciences, Kyushu University, 6-1 Kasugakoen, Kasuga, Fukuoka 816-8580 (Japan); Hossain, Md Shahriar Al [Institute for Superconducting and Electronic Materials, University of Wollongong, North Wollongong, New South Wales 2500 (Australia); Kim, Jung Ho, E-mail: jhk@uow.edu.au [Department of Physics and Astronomy, College of Science, P. O. Box 2455, King Saud University, Riyadh 11451 (Saudi Arabia); Institute for Superconducting and Electronic Materials, University of Wollongong, North Wollongong, New South Wales 2500 (Australia)

    2014-01-15

    A comprehensive study of the effects of structural imperfections in MgB{sub 2} superconducting wire has been conducted. As the sintering temperature becomes lower, the structural imperfections of the MgB{sub 2} material are increased, as reflected by detailed X-ray refinement and the normal state resistivity. The crystalline imperfections, caused by lattice disorder, directly affect the impurity scattering between the π and σ bands of MgB{sub 2}, resulting in a larger upper critical field. In addition, low sintering temperature keeps the grain size small, which leads to a strong enhancement of pinning, and thereby, enhanced critical current density. Owing to both the impurity scattering and the grain boundary pinning, the critical current density, irreversibility field, and upper critical field are enhanced. Residual voids or porosities obviously remain in the MgB{sub 2}, however, even at low sintering temperature, and thus block current transport paths.

  17. Effect of Sintering Atmosphere and Solution Treatment on Density, Microstructure and Tensile Properties of Duplex Stainless Steels Developed from Pre-alloyed Powders

    Science.gov (United States)

    Murali, Arun Prasad; Mahendran, Sudhahar; Ramajayam, Mariappan; Ganesan, Dharmalingam; Chinnaraj, Raj Kumar

    2017-10-01

    In this research, Powder Metallurgy (P/M) of Duplex Stainless Steels (DSS) of different compositions were prepared through pre-alloyed powders and elemental powders with and without addition of copper. The powder mix was developed by pot mill for 12 h to obtain the homogeneous mixture of pre-alloyed powder with elemental compositions. Cylindrical green compacts with the dimensions of 30 mm diameter and 12 mm height were compacted through universal testing machine at a pressure level of 560 ± 10 MPa. These green compacts were sintered at 1350 °C for 2 h in hydrogen and argon atmospheres. Some of the sintered stainless steel preforms were solution treated at 1050 °C followed by water quenching. The sintered as well as solution treated samples were analysed by metallography examination, Scanning Electron Microscopy and evaluation of mechanical properties. Ferrite content of sintered and solution treated DSS were measured by Fischer Ferritoscope. It is inferred that the hydrogen sintered DSS depicted better density (94% theoretical density) and tensile strength (695 MPa) than the argon sintered steels. Similarly the microstructure of solution treated DSS revealed existence of more volume of ferrite grains than its sintered condition. Solution treated hydrogen sintered DSS A (50 wt% 316L + 50 wt% 430L) exhibited higher tensile strength of 716 MPa and elongation of 17%, which are 10-13% increment than the sintered stainless steels.

  18. Birth weight, childhood body mass index, and height in relation to mammographic density and breast cancer

    DEFF Research Database (Denmark)

    Andersen, Zorana Jovanovic; Baker, Jennifer Lyn; Bihrmann, Kristine

    2014-01-01

    High breast density, a strong predictor of breast cancer may be determined early in life. Childhood anthropometric factors have been related to breast cancer and breast density, but rarely simultaneously. We examined whether mammographic density (MD) mediates an association of birth weight, child...

  19. Relative Density of Backfilled Soil Material around Monopiles for Offshore Wind Turbines

    DEFF Research Database (Denmark)

    Sørensen, Søren Peder Hyldal; Ibsen, Lars Bo; Frigaard, Peter

    2012-01-01

    The relative density of backfilled soil material around offshore monopiles is assessed through experimental testing in the Large Wave Channel (GWK) of the Coastal Research Centre (FZK) in Hannover. The relative density of the backfill material was found to vary between 65 and 80 %. The dependency...... of the relative density of backfill on the maximum pile bending moment is assessed through three-dimensional numerical modeling of a monopile foundation located at the offshore wind farm at Horns Reef, Denmark....

  20. Bone-related Circulating MicroRNAs miR-29b-3p, miR-550a-3p, and miR-324-3p and their Association to Bone Microstructure and Histomorphometry.

    Science.gov (United States)

    Feichtinger, Xaver; Muschitz, Christian; Heimel, Patrick; Baierl, Andreas; Fahrleitner-Pammer, Astrid; Redl, Heinz; Resch, Heinrich; Geiger, Elisabeth; Skalicky, Susanna; Dormann, Rainer; Plachel, Fabian; Pietschmann, Peter; Grillari, Johannes; Hackl, Matthias; Kocijan, Roland

    2018-03-20

    The assessment of bone quality and the prediction of fracture risk in idiopathic osteoporosis (IOP) are complex prospects as bone mineral density (BMD) and bone turnover markers (BTM) do not indicate fracture-risk. MicroRNAs (miRNAs) are promising new biomarkers for bone diseases, but the current understanding of the biological information contained in the variability of miRNAs is limited. Here, we investigated the association between serum-levels of 19 miRNA biomarkers of idiopathic osteoporosis to bone microstructure and bone histomorphometry based upon bone biopsies and µCT (9.3 μm) scans from 36 patients. Four miRNAs were found to be correlated to bone microarchitecture and seven miRNAs to dynamic histomorphometry (p microstructure parameters. miR-29b-3p and miR-324-p were found to be reduced in patients undergoing anti-resorptive therapy. This is the first study to report that serum levels of bone-related miRNAs might be surrogates of dynamic histomorphometry and potentially reveal changes in bone microstructure. Although these findings enhance the potential value of circulating miRNAs as bone biomarkers, further experimental studies are required to qualify the clinical utility of miRNAs to reflect dynamic changes in bone formation and microstructure.

  1. The causal relation between turbulent particle flux and density gradient

    Energy Technology Data Exchange (ETDEWEB)

    Milligen, B. Ph. van; Martín de Aguilera, A.; Hidalgo, C. [CIEMAT - Laboratorio Nacional de Fusión, Avda. Complutense 40, 28040 Madrid (Spain); Carreras, B. A. [BACV Solutions, 110 Mohawk Road, Oak Ridge, Tennessee 37830 (United States); García, L.; Nicolau, J. H. [Universidad Carlos III, 28911 Leganés, Madrid (Spain)

    2016-07-15

    A technique for detecting the causal relationship between fluctuating signals is used to investigate the relation between flux and gradient in fusion plasmas. Both a resistive pressure gradient driven turbulence model and experimental Langmuir probe data from the TJ-II stellarator are studied. It is found that the maximum influence occurs at a finite time lag (non-instantaneous response) and that quasi-periodicities exist. Furthermore, the model results show very long range radial influences, extending over most of the investigated regions, possibly related to coupling effects associated with plasma self-organization. These results clearly show that transport in fusion plasmas is not local and instantaneous, as is sometimes assumed.

  2. High energy density physics issues related to Future Circular Collider

    Science.gov (United States)

    Tahir, N. A.; Burkart, F.; Schmidt, R.; Shutov, A.; Wollmann, D.; Piriz, A. R.

    2017-07-01

    A design study for a post-Large Hadron Collider accelerator named, Future Circular Collider (FCC), is being carried out by the International Scientific Community. A complete design report is expected to be ready by spring 2018. The FCC will accelerate two counter rotating beams of 50 TeV protons in a tunnel having a length (circumference) of 100 km. Each beam will be comprised of 10 600 proton bunches, with each bunch having an intensity of 1011 protons. The bunch length is of 0.5 ns, and two neighboring bunches are separated by 25 ns. Although there is an option for 5 ns bunch separation as well, in the present studies, we consider the former case only. The total energy stored in each FCC beam is about 8.5 GJ, which is equivalent to the kinetic energy of Airbus 380 (560 t) flying at a speed of 850 km/h. Machine protection is a very important issue while operating with such powerful beams. It is important to have an estimate of the damage caused to the equipment and accelerator components due to the accidental release of a partial or total beam at a given point. For this purpose, we carried out numerical simulations of full impact of one FCC beam on an extended solid copper target. These simulations have been done employing an energy deposition code, FLUKA, and a two-dimensional hydrodynamic code, BIG2, iteratively. This study shows that although the static range of a single FCC proton and its shower is about 1.5 m in solid copper, the entire beam will penetrate around 350 m into the target. This substantial increase in the range is due to the hydrodynamic tunneling of the beam. Our calculations also show that a large part of the target will be converted into high energy density matter including warm dense matter and strongly coupled plasmas.

  3. Relations between the density matrix and thermodynamic potential

    International Nuclear Information System (INIS)

    Pitanga, P.; Mundim, K.C.

    1988-01-01

    We propose to study the stability of a polyatomic molecular system in terms of the thermodynamic potential G. This enables us to establish a relation between the bond index and susceptibility tensor ∂ 2 G/∂μ i ∂ j . (author) [pt

  4. Bird Density and Distribution Patterns in Relation to Anthropogenic ...

    African Journals Online (AJOL)

    In the river, human activity and water quality had no clear effect on the avifauna. ... which trophic relations might be altered and community ... from the bridge to sea, dividing the river into four 200 m sections ... made of vegetation cover at ground level, 1,. 2 and 3 m ... analysed using the Shannon diversity index. H′ to obtain ...

  5. Ceramic coatings: A phenomenological modeling for damping behavior related to microstructural features

    International Nuclear Information System (INIS)

    Tassini, N.; Patsias, S.; Lambrinou, K.

    2006-01-01

    Recent research has shown that both stiffness and damping of ceramic coatings exhibit different non-linearities. These properties strongly depend on the microstructure, which is characterized by heterogeneous sets of elastic elements with mesoscopic sizes and shapes, as in non-linear mesoscopic elastic materials. To predict the damping properties of this class of materials, we have implemented a phenomenological model that characterizes their elastic properties. The model is capable of reproducing the basic features of the observed damping behavior for zirconia coatings prepared by air plasma spraying and electron-beam physical-vapor-deposition

  6. Altered microstructural connectivity of the superior cerebellar peduncle is related to motor dysfunction in children with autistic spectrum disorders.

    Science.gov (United States)

    Hanaie, Ryuzo; Mohri, Ikuko; Kagitani-Shimono, Kuriko; Tachibana, Masaya; Azuma, Junji; Matsuzaki, Junko; Watanabe, Yoshiyuki; Fujita, Norihiko; Taniike, Masako

    2013-10-01

    Many studies have reported motor impairments in autistic spectrum disorders (ASD). However, the brain mechanism underlying motor impairment in ASD remains unclear. Recent neuroimaging studies have suggested that underconnectivity between the cerebellum and other brain regions contributes to the features of ASD. In this study, we investigated the microstructural integrity of the cerebellar pathways, including the superior, middle, and inferior cerebellar peduncles, of children with and without ASD by using diffusion tensor imaging (DTI) tractography to determine whether the microstructural integrity of the cerebellar pathways is related to motor function in children with ASD. Thirteen children with ASD and 11 age-, gender-, handedness-, and IQ-matched typically developing (TD) controls were enrolled in this study. DTI outcome measurements, such as fractional anisotropy (FA), axial diffusivity (AD), and radial diffusivity (RD), for the cerebellar pathways were calculated. The Movement Assessment Battery for Children 2 (M-ABC 2) was used for assessing motor functions. There were no significant differences between the two groups in RD. However, compared to the TD subjects, patients with ASD had a significantly lower FA in the right superior cerebellar peduncle and lower AD in the left superior cerebellar peduncle, in addition to a significantly lower score in ball skills and the total test score of M-ABC 2. There was a significant positive correlation between the total test score of M-ABC 2 and FA in the right superior cerebellar peduncle in the ASD group. These findings suggest that the altered microstructural integrity of the superior cerebellar peduncle may be related to motor impairment in ASD.

  7. Microstructural changes in cartilage and bone related to repetitive overloading in an equine athlete model.

    Science.gov (United States)

    Turley, Sean M; Thambyah, Ashvin; Riggs, Christopher M; Firth, Elwyn C; Broom, Neil D

    2014-06-01

    The palmar aspect of the third metacarpal (MC3) condyle of equine athletes is known to be subjected to repetitive overloading that can lead to the accumulation of joint tissue damage, degeneration, and stress fractures, some of which result in catastrophic failure. However, there is still a need to understand at a detailed microstructural level how this damage progresses in the context of the wider joint tissue complex, i.e. the articular surface, the hyaline and calcified cartilage, and the subchondral bone. MC3 bones from non-fractured joints were obtained from the right forelimbs of 16 Thoroughbred racehorses varying in age between 3 and 8 years, with documented histories of active race training. Detailed microstructural analysis of two clinically important sites, the parasagittal grooves and the mid-condylar regions, identified extensive levels of microdamage in the calcified cartilage and subchondral bone concealed beneath outwardly intact hyaline cartilage. The study shows a progression in microdamage severity, commencing with mild hard-tissue microcracking in younger animals and escalating to severe subchondral bone collapse and lesion formation in the hyaline cartilage with increasing age and thus athletic activity. The presence of a clearly distinguishable fibrous tissue layer at the articular surface immediately above sites of severe subchondral collapse suggested a limited reparative response in the hyaline cartilage. © 2014 Anatomical Society.

  8. Microstructural changes in cartilage and bone related to repetitive overloading in an equine athlete model

    Science.gov (United States)

    Turley, Sean M; Thambyah, Ashvin; Riggs, Christopher M; Firth, Elwyn C; Broom, Neil D

    2014-01-01

    The palmar aspect of the third metacarpal (MC3) condyle of equine athletes is known to be subjected to repetitive overloading that can lead to the accumulation of joint tissue damage, degeneration, and stress fractures, some of which result in catastrophic failure. However, there is still a need to understand at a detailed microstructural level how this damage progresses in the context of the wider joint tissue complex, i.e. the articular surface, the hyaline and calcified cartilage, and the subchondral bone. MC3 bones from non-fractured joints were obtained from the right forelimbs of 16 Thoroughbred racehorses varying in age between 3 and 8 years, with documented histories of active race training. Detailed microstructural analysis of two clinically important sites, the parasagittal grooves and the mid-condylar regions, identified extensive levels of microdamage in the calcified cartilage and subchondral bone concealed beneath outwardly intact hyaline cartilage. The study shows a progression in microdamage severity, commencing with mild hard-tissue microcracking in younger animals and escalating to severe subchondral bone collapse and lesion formation in the hyaline cartilage with increasing age and thus athletic activity. The presence of a clearly distinguishable fibrous tissue layer at the articular surface immediately above sites of severe subchondral collapse suggested a limited reparative response in the hyaline cartilage. PMID:24689513

  9. Microstructural Characterization of a Mg Matrix U-Mo Dispersion Fuel Plate Irradiated in the Advanced Test Reactor to High Fission Density: SEM Results

    Science.gov (United States)

    Keiser, Dennis D.; Jue, Jan-Fong; Miller, Brandon D.; Gan, Jian; Robinson, Adam B.; Medvedev, Pavel G.; Madden, James W.; Moore, Glenn A.

    2016-06-01

    Low-enriched (U-235 RERTR-8 experiment at high temperature, high fission rate, and high power, up to high fission density. This paper describes the results of the scanning electron microscopy (SEM) analysis of an irradiated fuel plate using polished samples and those produced with a focused ion beam. A follow-up paper will discuss the results of transmission electron microscopy (TEM) analysis. Using SEM, it was observed that even at very aggressive irradiation conditions, negligible chemical interaction occurred between the irradiated U-7Mo fuel particles and Mg matrix; no interconnection of fission gas bubbles from fuel particle to fuel particle was observed; the interconnected fission gas bubbles that were observed in the irradiated U-7Mo particles resulted in some transport of solid fission products to the U-7Mo/Mg interface; the presence of microstructural pathways in some U-9.1 Mo particles that could allow for transport of fission gases did not result in the apparent presence of large porosity at the U-7Mo/Mg interface; and, the Mg-Al interaction layers that were present at the Mg matrix/Al 6061 cladding interface exhibited good radiation stability, i.e. no large pores.

  10. Effects of graphite doping on critical current density and microstructure of MgB2 bulks by an improved Mg-diffusion method

    International Nuclear Information System (INIS)

    Pan, X.F.; Zhao, Y.; Feng, Y.; Yang, Y.; Cheng, C.H.

    2008-01-01

    abstract: A series of graphite-doped MgB 2 bulks with high density have been successfully prepared by an improved Mg-diffusion method in ambient pressure. The effects of graphite doping on lattice parameters, T c , J c and microstructure of MgB 2 have been investigated. The results show that compared to the nano-C-doped or CNTs-doped MgB 2 , C is not easy to substitute B in graphite-doped MgB 2 . However, at the same C content, the graphite-doped MgB 2 has a higher J c . At 10 K and self-field, the J c for MgB 1.985 C 0.015 reaches 0.58 MA/cm 2 . For the MgB 1.945 C 0.055 , at 5 K, 7 T and 10 K, 6 T the J c achieves 10,000 A/cm 2 which is two orders of magnitude higher than that for the undoped sample. In addition to improving electron scattering and intergranular connectivity, the unreacted graphite in the graphite-doped MgB 2 is proposed to be responsible to the excellent J c properties of MgB 2 in high fields, due to depressed grain growth and enhanced grain boundary flux pinning

  11. Feed intake as explanation for density related growth differences of common sole Solea solea

    DEFF Research Database (Denmark)

    Lund, Ivar; Steenfeldt, Svend Jørgen; Herrmann, Bent

    2013-01-01

    correlated to both fish size and individual SGR. Feed conversion ratio was likewise positively correlated to feed intake. The relative feed intake (g feed g fish−1) was not correlated to fish size at any density tested, but was significantly highest for the LD population. This explains a substantial part......Growth of common sole Solea solea is negatively correlated to density, which affects productivity in culture and hence commercial success. Studies of individual feed intake were performed to examine growth and population dynamics at different densities. Three initial stocking densities: 1.0, 2.......1 and 3.9 kg m−2 of individually tagged sole, referred to as low density (LD), medium density and high density HD), were examined during 145 days. Despite that tank productivity (g m−2 day−1), was highest for the HD group, the specific growth rate (SGR) decreased significantly with increase in stocking...

  12. Banks-Casher-type relation for the BCS gap at high density

    OpenAIRE

    Kanazawa, Takuya; Wettig, Tilo; Yamamoto, Naoki

    2012-01-01

    We derive a new Banks-Casher-type relation which relates the density of complex Dirac eigenvalues at the origin to the BCS gap of quarks at high density. Our relation is applicable to QCD and QCD-like theories without a sign problem, such as two-color QCD and adjoint QCD with baryon chemical potential, and QCD with isospin chemical potential. It provides us with a method to measure the BCS gap through the Dirac spectrum on the lattice.

  13. Measurements relating fire radiative energy density and surface fuel consumption - RxCADRE 2011 and 2012

    Science.gov (United States)

    Andrew T. Hudak; Matthew B. Dickinson; Benjamin C. Bright; Robert L. Kremens; E. Louise Loudermilk; Joseph J. O' Brien; Benjamin S. Hornsby; Roger D. Ottmar

    2016-01-01

    Small-scale experiments have demonstrated that fire radiative energy is linearly related to fuel combusted but such a relationship has not been shown at the landscape level of prescribed fires. This paper presents field and remotely sensed measures of pre-fire fuel loads, consumption, fire radiative energy density (FRED) and fire radiative power flux density (FRFD),...

  14. Development of white matter microstructure in relation to verbal and visuospatial working memory-A longitudinal study.

    Science.gov (United States)

    Krogsrud, Stine K; Fjell, Anders M; Tamnes, Christian K; Grydeland, Håkon; Due-Tønnessen, Paulina; Bjørnerud, Atle; Sampaio-Baptista, Cassandra; Andersson, Jesper; Johansen-Berg, Heidi; Walhovd, Kristine B

    2018-01-01

    Working memory capacity is pivotal for a broad specter of cognitive tasks and develops throughout childhood. This must in part rely on development of neural connections and white matter microstructure maturation, but there is scarce knowledge of specific relations between this and different aspects of working memory. Diffusion tensor imaging (DTI) enables us to study development of brain white matter microstructure. In a longitudinal DTI study of 148 healthy children between 4 and 11 years scanned twice with an on average 1.6 years interval, we characterized change in fractional anisotropy (FA), mean (MD), radial (RD) and axial diffusivity (AD) in 10 major white matter tracts hypothesized to be of importance for working memory. The results showed relationships between change in several tracts and change in visuospatial working memory. Specifically, improvement in visuospatial working memory capacity was significantly associated with decreased MD, RD and AD in inferior longitudinal fasciculus (ILF), inferior fronto-occipital fasciculus (IFOF) and uncinate fasciculus (UF) in the right hemisphere, as well as forceps major (FMaj). No significant relationships were found between change in DTI metrics and change in verbal working memory capacity. These findings yield new knowledge about brain development and corresponding working memory improvements in childhood.

  15. Development of white matter microstructure in relation to verbal and visuospatial working memory—A longitudinal study

    Science.gov (United States)

    Fjell, Anders M.; Tamnes, Christian K.; Grydeland, Håkon; Due-Tønnessen, Paulina; Bjørnerud, Atle; Sampaio-Baptista, Cassandra; Andersson, Jesper; Johansen-Berg, Heidi; Walhovd, Kristine B.

    2018-01-01

    Working memory capacity is pivotal for a broad specter of cognitive tasks and develops throughout childhood. This must in part rely on development of neural connections and white matter microstructure maturation, but there is scarce knowledge of specific relations between this and different aspects of working memory. Diffusion tensor imaging (DTI) enables us to study development of brain white matter microstructure. In a longitudinal DTI study of 148 healthy children between 4 and 11 years scanned twice with an on average 1.6 years interval, we characterized change in fractional anisotropy (FA), mean (MD), radial (RD) and axial diffusivity (AD) in 10 major white matter tracts hypothesized to be of importance for working memory. The results showed relationships between change in several tracts and change in visuospatial working memory. Specifically, improvement in visuospatial working memory capacity was significantly associated with decreased MD, RD and AD in inferior longitudinal fasciculus (ILF), inferior fronto-occipital fasciculus (IFOF) and uncinate fasciculus (UF) in the right hemisphere, as well as forceps major (FMaj). No significant relationships were found between change in DTI metrics and change in verbal working memory capacity. These findings yield new knowledge about brain development and corresponding working memory improvements in childhood. PMID:29689058

  16. Cone photopigment in older subjects: decreased optical density in early age-related macular degeneration

    Science.gov (United States)

    Elsner, Ann E.; Burns, Stephen A.; Weiter, John J.

    2002-01-01

    We measured changes to cone photoreceptors in patients with early age-related macular degeneration. The data of 53 patients were compared with normative data for color matching measurements of long- and middle-wavelength-sensitive cones in the central macula. A four-parameter model quantified cone photopigment optical density and kinetics. Cone photopigment optical density was on average less for the patients than for normal subjects and was uncorrelated with visual acuity. More light was needed to reduce the photopigment density by 50% in the steady state for patients. These results imply that cone photopigment optical density is reduced by factors other than slowed kinetics.

  17. Effects of graphite doping on critical current density and microstructure of MgB{sub 2} bulks by an improved Mg-diffusion method

    Energy Technology Data Exchange (ETDEWEB)

    Pan, X.F. [Key Laboratory of Magnetic Levitation and Maglev Trains (Ministry of Education of China), Superconductivity R and D Center (SRDC), Mail Stop 165, Southwest Jiaotong University, Chengdu, Sichuan 610031 (China); Zhao, Y. [Key Laboratory of Magnetic Levitation and Maglev Trains (Ministry of Education of China), Superconductivity R and D Center (SRDC), Mail Stop 165, Southwest Jiaotong University, Chengdu, Sichuan 610031 (China); School of Materials Science and Engineering, University of New South Wales, Sydney 2052, NSW (Australia)], E-mail: yshao@home.swjtu.edu.cn; Feng, Y. [Northwest Institute for Nonferrous Metal Research, P.O. Box 51, Xi' an, Shaanxi 710016 (China); Western Superconductivity Technology Company, Xi' an (China); Yang, Y. [Key Laboratory of Magnetic Levitation and Maglev Trains (Ministry of Education of China), Superconductivity R and D Center (SRDC), Mail Stop 165, Southwest Jiaotong University, Chengdu, Sichuan 610031 (China); Cheng, C.H. [Key Laboratory of Magnetic Levitation and Maglev Trains (Ministry of Education of China), Superconductivity R and D Center (SRDC), Mail Stop 165, Southwest Jiaotong University, Chengdu, Sichuan 610031 (China); School of Materials Science and Engineering, University of New South Wales, Sydney 2052, NSW (Australia)

    2008-09-15

    abstract: A series of graphite-doped MgB{sub 2} bulks with high density have been successfully prepared by an improved Mg-diffusion method in ambient pressure. The effects of graphite doping on lattice parameters, T{sub c}, J{sub c} and microstructure of MgB{sub 2} have been investigated. The results show that compared to the nano-C-doped or CNTs-doped MgB{sub 2}, C is not easy to substitute B in graphite-doped MgB{sub 2}. However, at the same C content, the graphite-doped MgB{sub 2} has a higher J{sub c}. At 10 K and self-field, the J{sub c} for MgB{sub 1.985}C{sub 0.015} reaches 0.58 MA/cm{sup 2}. For the MgB{sub 1.945}C{sub 0.055}, at 5 K, 7 T and 10 K, 6 T the J{sub c} achieves 10,000 A/cm{sup 2} which is two orders of magnitude higher than that for the undoped sample. In addition to improving electron scattering and intergranular connectivity, the unreacted graphite in the graphite-doped MgB{sub 2} is proposed to be responsible to the excellent J{sub c} properties of MgB{sub 2} in high fields, due to depressed grain growth and enhanced grain boundary flux pinning.

  18. Observer variability of absolute and relative thrombus density measurements in patients with acute ischemic stroke

    International Nuclear Information System (INIS)

    Santos, Emilie M.M.; Yoo, Albert J.; Beenen, Ludo F.; Majoie, Charles B.; Berkhemer, Olvert A.; Blanken, Mark D. den; Wismans, Carrie; Niessen, Wiro J.; Marquering, Henk A.

    2016-01-01

    Thrombus density may be a predictor for acute ischemic stroke treatment success. However, only limited data on observer variability for thrombus density measurements exist. This study assesses the variability and bias of four common thrombus density measurement methods by expert and non-expert observers. For 132 consecutive patients with acute ischemic stroke, three experts and two trained observers determined thrombus density by placing three standardized regions of interest (ROIs) in the thrombus and corresponding contralateral arterial segment. Subsequently, absolute and relative thrombus densities were determined using either one or three ROIs. Intraclass correlation coefficient (ICC) was determined, and Bland-Altman analysis was performed to evaluate interobserver and intermethod agreement. Accuracy of the trained observer was evaluated with a reference expert observer using the same statistical analysis. The highest interobserver agreement was obtained for absolute thrombus measurements using three ROIs (ICCs ranging from 0.54 to 0.91). In general, interobserver agreement was lower for relative measurements, and for using one instead of three ROIs. Interobserver agreement of trained non-experts and experts was similar. Accuracy of the trained observer measurements was comparable to the expert interobserver agreement and was better for absolute measurements and with three ROIs. The agreement between the one ROI and three ROI methods was good. Absolute thrombus density measurement has superior interobserver agreement compared to relative density measurement. Interobserver variation is smaller when multiple ROIs are used. Trained non-expert observers can accurately and reproducibly assess absolute thrombus densities using three ROIs. (orig.)

  19. Observer variability of absolute and relative thrombus density measurements in patients with acute ischemic stroke

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Emilie M.M. [Erasmus MC - University Medical Center Rotterdam, Department of Radiology, P.O. Box 2040, Rotterdam (Netherlands); Department of Radiology, AMC, Amsterdam (Netherlands); Yoo, Albert J. [Texas Stroke Institute, Plano, TX (United States); Beenen, Ludo F.; Majoie, Charles B. [Department of Radiology, AMC, Amsterdam (Netherlands); Berkhemer, Olvert A. [Department of Radiology, AMC, Amsterdam (Netherlands); Department of Neurology, Erasmus MC, Rotterdam (Netherlands); Blanken, Mark D. den; Wismans, Carrie [AMC, Department of Biomedical Engineering and Physics, Amsterdam (Netherlands); Niessen, Wiro J. [Erasmus MC - University Medical Center Rotterdam, Department of Radiology, P.O. Box 2040, Rotterdam (Netherlands); Delft University of Technology, Faculty of Applied Sciences, Delft (Netherlands); Marquering, Henk A. [Department of Radiology, AMC, Amsterdam (Netherlands); AMC, Department of Biomedical Engineering and Physics, Amsterdam (Netherlands); Collaboration: on behalf of the MR CLEAN investigators

    2016-02-15

    Thrombus density may be a predictor for acute ischemic stroke treatment success. However, only limited data on observer variability for thrombus density measurements exist. This study assesses the variability and bias of four common thrombus density measurement methods by expert and non-expert observers. For 132 consecutive patients with acute ischemic stroke, three experts and two trained observers determined thrombus density by placing three standardized regions of interest (ROIs) in the thrombus and corresponding contralateral arterial segment. Subsequently, absolute and relative thrombus densities were determined using either one or three ROIs. Intraclass correlation coefficient (ICC) was determined, and Bland-Altman analysis was performed to evaluate interobserver and intermethod agreement. Accuracy of the trained observer was evaluated with a reference expert observer using the same statistical analysis. The highest interobserver agreement was obtained for absolute thrombus measurements using three ROIs (ICCs ranging from 0.54 to 0.91). In general, interobserver agreement was lower for relative measurements, and for using one instead of three ROIs. Interobserver agreement of trained non-experts and experts was similar. Accuracy of the trained observer measurements was comparable to the expert interobserver agreement and was better for absolute measurements and with three ROIs. The agreement between the one ROI and three ROI methods was good. Absolute thrombus density measurement has superior interobserver agreement compared to relative density measurement. Interobserver variation is smaller when multiple ROIs are used. Trained non-expert observers can accurately and reproducibly assess absolute thrombus densities using three ROIs. (orig.)

  20. Ionization Potentials of Chemical Warfare Agents and Related Compounds Determined with Density Functional Theory

    National Research Council Canada - National Science Library

    Wright, J

    2000-01-01

    ...) agents at contaminated sites. Reported herein are theoretical ionization potentials for CW agents and their related compounds calculated using density functional theory at the B3LYP/6-311+G(2d,p) level of theory...

  1. Fragmentation of massive dense cores down to ≲ 1000 AU: Relation between fragmentation and density structure

    International Nuclear Information System (INIS)

    Palau, Aina; Girart, Josep M.; Estalella, Robert; Fuente, Asunción; Fontani, Francesco; Sánchez-Monge, Álvaro; Commerçon, Benoit; Hennebelle, Patrick; Busquet, Gemma; Bontemps, Sylvain; Zapata, Luis A.; Zhang, Qizhou; Di Francesco, James

    2014-01-01

    In order to shed light on the main physical processes controlling fragmentation of massive dense cores, we present a uniform study of the density structure of 19 massive dense cores, selected to be at similar evolutionary stages, for which their relative fragmentation level was assessed in a previous work. We inferred the density structure of the 19 cores through a simultaneous fit of the radial intensity profiles at 450 and 850 μm (or 1.2 mm in two cases) and the spectral energy distribution, assuming spherical symmetry and that the density and temperature of the cores decrease with radius following power-laws. Even though the estimated fragmentation level is strictly speaking a lower limit, its relative value is significant and several trends could be explored with our data. We find a weak (inverse) trend of fragmentation level and density power-law index, with steeper density profiles tending to show lower fragmentation, and vice versa. In addition, we find a trend of fragmentation increasing with density within a given radius, which arises from a combination of flat density profile and high central density and is consistent with Jeans fragmentation. We considered the effects of rotational-to-gravitational energy ratio, non-thermal velocity dispersion, and turbulence mode on the density structure of the cores, and found that compressive turbulence seems to yield higher central densities. Finally, a possible explanation for the origin of cores with concentrated density profiles, which are the cores showing no fragmentation, could be related with a strong magnetic field, consistent with the outcome of radiation magnetohydrodynamic simulations.

  2. Fragmentation of massive dense cores down to ≲ 1000 AU: Relation between fragmentation and density structure

    Energy Technology Data Exchange (ETDEWEB)

    Palau, Aina; Girart, Josep M. [Institut de Ciències de l' Espai (CSIC-IEEC), Campus UAB-Facultat de Ciències, Torre C5-parell 2, E-08193 Bellaterra, Catalunya (Spain); Estalella, Robert [Departament d' Astronomia i Meteorologia (IEEC-UB), Institut de Ciències del Cosmos, Universitat de Barcelona, Martí i Franquès, 1, E-08028 Barcelona (Spain); Fuente, Asunción [Observatorio Astronómico Nacional, P.O. Box 112, E-28803 Alcalá de Henares, Madrid (Spain); Fontani, Francesco; Sánchez-Monge, Álvaro [Osservatorio Astrofisico di Arcetri, INAF, Lago E. Fermi 5, I-50125 Firenze (Italy); Commerçon, Benoit; Hennebelle, Patrick [Laboratoire de Radioastronomie, UMR CNRS 8112, École Normale Supérieure et Observatoire de Paris, 24 rue Lhomond, F-75231 Paris Cedex 05 (France); Busquet, Gemma [INAF-Istituto di Astrofisica e Planetologia Spaziali, Area di Recerca di Tor Vergata, Via Fosso Cavaliere 100, I-00133 Roma (Italy); Bontemps, Sylvain [Université de Bordeaux, LAB, UMR 5804, F-33270 Floirac (France); Zapata, Luis A. [Centro de Radioastronomía y Astrofísica, Universidad Nacional Autónoma de México, P.O. Box 3-72, 58090 Morelia, Michoacán (Mexico); Zhang, Qizhou [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Di Francesco, James, E-mail: palau@ieec.uab.es [Department of Physics and Astronomy, University of Victoria, P.O. Box 355, STN CSC, Victoria, BC, V8W 3P6 (Canada)

    2014-04-10

    In order to shed light on the main physical processes controlling fragmentation of massive dense cores, we present a uniform study of the density structure of 19 massive dense cores, selected to be at similar evolutionary stages, for which their relative fragmentation level was assessed in a previous work. We inferred the density structure of the 19 cores through a simultaneous fit of the radial intensity profiles at 450 and 850 μm (or 1.2 mm in two cases) and the spectral energy distribution, assuming spherical symmetry and that the density and temperature of the cores decrease with radius following power-laws. Even though the estimated fragmentation level is strictly speaking a lower limit, its relative value is significant and several trends could be explored with our data. We find a weak (inverse) trend of fragmentation level and density power-law index, with steeper density profiles tending to show lower fragmentation, and vice versa. In addition, we find a trend of fragmentation increasing with density within a given radius, which arises from a combination of flat density profile and high central density and is consistent with Jeans fragmentation. We considered the effects of rotational-to-gravitational energy ratio, non-thermal velocity dispersion, and turbulence mode on the density structure of the cores, and found that compressive turbulence seems to yield higher central densities. Finally, a possible explanation for the origin of cores with concentrated density profiles, which are the cores showing no fragmentation, could be related with a strong magnetic field, consistent with the outcome of radiation magnetohydrodynamic simulations.

  3. Cyclil Oxidation Behaviors of MoSi2 with Different Relative Density

    Institute of Scientific and Technical Information of China (English)

    YAN Jianhui; ZHANG Houan; TANG Siwen; XU Jianguang

    2008-01-01

    The influence of different relative density on the cyclic oxidation behaviors of MoSi2 at 1 273 K were studied. "Pesting" was not found in all MoSi2 materials after being oxidized for 480 h. All samples exhibited continuous mass gain during the oxidation process. The mass gains of MoSi2 with the lowest relative density (78.6%) and the highest relative density (94.8%) are increased by 8.15 mg·cm2 and 3.48 mg·cm-2, respectively. The surface of the material with lower relative density formed a loose, porous and discontinuous oxidation scale, which accelerated oxygen diffusion and aggravated the oxidation process. However, a dense scale in the material with higher relative density is formed, which acts a diffusion barrier to the oxygen atoms penetrating into the matrix. The high temperature oxidation resistance of MoSi2 can be improved by increasing its relative density.

  4. Are energy-dense foods really cheaper? Reexamining the relation between food price and energy density.

    Science.gov (United States)

    Lipsky, Leah M

    2009-11-01

    The inverse relation between energy density (kcal/g) and energy cost (price/kcal) has been interpreted to suggest that produce (fruit, vegetables) is more expensive than snacks (cookies, chips). The objective of this study was to show the methodologic weakness of comparing energy density with energy cost. The relation between energy density and energy cost was replicated in a random-number data set. Additionally, observational data were collected for produce and snacks from an online supermarket. Variables included total energy (kcal), total weight (g), total number of servings, serving size (g/serving), and energy density (kcal/g). Price measures included energy cost ($/kcal), total price ($), unit price ($/g), and serving price ($/serving). Two-tailed t tests were used to compare price measures by food category. Relations between energy density and price measures within food categories were examined with the use of Spearman rank correlation analysis. The relation between energy density and energy cost was shown to be driven by the algebraic properties of these variables. Food category was strongly correlated with both energy density and food price measures. Energy cost was higher for produce than for snacks. However, total price and unit price were lower for produce. Serving price and serving size were greater for produce than for snacks. Within food categories, energy density was uncorrelated with most measures of food price, except for a weak positive correlation with serving price within the produce category. The findings suggest the relation between energy density and food price is confounded by food category and depends on which measure of price is used.

  5. Relative floral density of an invasive plant affects pollinator foraging behaviour on a native plant

    Directory of Open Access Journals (Sweden)

    Amy Marie Iler

    2014-08-01

    Full Text Available Interactions between invasive and native plants for pollinators vary from competition to facilitation of pollination of native plants. Theory predicts that relative floral densities should account for some of this variation in outcomes, with facilitation at low floral densities and competition at high floral densities of the invader. We tested this prediction by quantifying pollination and female reproductive success of a native herb, Geranium maculatum, in three experimental arrays that varied in floral density of the invasive shrub Lonicera maackii: control (no L. maackii, low floral density of L. maackii, and high floral density of L. maackii. A low density of L. maackii flowers was associated with an increase in pollinator visitation rate to G. maculatum flowers and an increase in conspecific pollen deposition compared to controls and high density arrays. Increased visitation rates were not associated with an increase in the number of visitors to low density arrays, suggesting instead that a behavioural switch in visitation within the array accounted for increased pollen deposition. In contrast, the only evidence of competition in high density arrays was a shorter duration of visits to G. maculatum flowers relative to the other treatments. The number of seeds per flower did not vary among treatments, although trends in seeds per flower were consistent with patterns of pollinator foraging behaviour. Given increased pollinator visits and pollen deposition at a low density of the invader, our study indicates that complete eradication of invasives as a management or restoration technique may have unintended negative consequences for pollination of native plants.

  6. Relation between microstructure and adhesion of hot dip galvanized zinc coatings on dual phase steel

    International Nuclear Information System (INIS)

    Song, G.M.; Vystavel, T.; Pers, N. van der; De Hosson, J.Th.M.; Sloof, W.G.

    2012-01-01

    Highlights: ► Amorphous manganese oxides present at the steel surface impair the adhesion of the zinc coating. ► The adhesion of the various interfaces that exist in zinc coated steel is quantitatively estimated using the “Macroscopic Atom” model. ► Zinc coating delaminates along the zinc layer/inhibition layer and ζ-FeZn 13 particle/inhibition layer interfaces, which agrees the theoretical calculation. - Abstract: The microstructure of hot dip galvanized zinc coatings on dual phase steel was investigated by electron microscopy and the coating adhesion characterized by tensile testing. The zinc coating consists of a zinc layer and columnar ζ-FeZn 13 particles on top of a thin inhibition layer adjacent to the steel substrate. The inhibition layer is a thin compact and continuous layer that consists of η-Fe 2 Al 5–x Zn x fine and coarse particles. The coarse faceted particles are on top and fine faceted particles are at the bottom. The steel surface is covered with small fraction manganese oxides, which may impair adhesion of the zinc coating. The adhesion at various interfaces that exist in zinc-coated steel was quantitatively estimated using a so-called “macroscopic atom” model. In addition, the adhesion at the interfaces in zinc-coated steel was qualitatively assessed by examining the fracture and delamination behavior upon tensile testing. In accordance with this model, fracture along zinc grain boundaries preceded fracture along the zinc layer/inhibition layer and ζ-FeZn 13 particle/inhibition layer interfaces.

  7. Relation between Microstructure and Charge Transport in Polymers of Different Regioregularity

    KAUST Repository

    McMahon, David P.; Cheung, David L.; Goris, Ludwig; Dacuña, Javier; Salleo, Alberto; Troisi, Alessandro

    2011-01-01

    A methodology to link an atomistic description of a polymeric semiconductor with the experimental electrical characteristics of real devices is proposed. Microscopic models of poly(3-hexylthiophene) (P3HT) of different regioregularity are generated using molecular dynamics and their electronic structure determined via an approximate quantum chemistry scheme. The resulting density of trap states and distribution of localized and delocalized states is then compared with that obtained from thin film transistor measurements of P3HT at different regioregularities. The two complementary methodologies provide a converging description of the electron transport in semicrystalline P3HT and the role of regioregularity. States at the valence band edge are localized, but delocalized "band-like" states are thermally accessible and quantitatively characterized. Both theory and experiment agree that contrary to a commonly held belief the trap density and the DOS shape are little affected by the presence of regioregularity defects. © 2011 American Chemical Society.

  8. Relation between Microstructure and Charge Transport in Polymers of Different Regioregularity

    KAUST Repository

    McMahon, David P.

    2011-10-06

    A methodology to link an atomistic description of a polymeric semiconductor with the experimental electrical characteristics of real devices is proposed. Microscopic models of poly(3-hexylthiophene) (P3HT) of different regioregularity are generated using molecular dynamics and their electronic structure determined via an approximate quantum chemistry scheme. The resulting density of trap states and distribution of localized and delocalized states is then compared with that obtained from thin film transistor measurements of P3HT at different regioregularities. The two complementary methodologies provide a converging description of the electron transport in semicrystalline P3HT and the role of regioregularity. States at the valence band edge are localized, but delocalized "band-like" states are thermally accessible and quantitatively characterized. Both theory and experiment agree that contrary to a commonly held belief the trap density and the DOS shape are little affected by the presence of regioregularity defects. © 2011 American Chemical Society.

  9. Production of litter and detritus related to the density of mangrove

    Science.gov (United States)

    Budi Mulya, Miswar; Arlen, HJ

    2018-03-01

    Research about the production of leaf litter and detritus related to the density of mangrove trees has been done. The aims of this research are to know and analyze the amount of litter and detritus produced to the density of mangrove trees. The production and collection of leaf litter were carried out in five stations. Production of detritus and decomposition rate were calculated by measuring its dry weight. The density and level of mangrove trees were determined using transect quadratic method. The relationship between the leaf litter and detritus production ratio related to mangrove density were then analyzed. Results showed that mangrove trees with the density of 766.67 ind ha‑1 ccould produce the amount of litter and detritus to about 28597.33 gha‑1day‑1and 1099.35 gha‑1day‑1 while mangrove trees with the density of 1300 ind ha‑1 could produce the amount of litter and detritus to about 35093.33 g/ha/day and 1216.68 gha‑1day‑1 respectively. Data analysis showed that the increment of mangrove density is linearly related to the production increment of litter and detritus.

  10. Seasonal photosynthesis and water relations of juvenile loblolly pine relative to stand density and canopy position

    Science.gov (United States)

    Zhenmin Tang; Jim L. Chambers; Mary A. Sword Sayer; James P. Barnett

    2003-01-01

    To assess the effects of stand density and canopy environment on tree physiology, we measured gas exchange responses of the same needle age class of 16-year-old loblolly pines (Pinus taeda L.) in thinned (512 trees ha-1) and non-thinned treatment plots (2,863 trees ha-1) in central Louisiana....

  11. Breast density and mode of detection in relation to breast cancer specific survival: a cohort study

    International Nuclear Information System (INIS)

    Olsson, Åsa; Sartor, Hanna; Borgquist, Signe; Zackrisson, Sophia; Manjer, Jonas

    2014-01-01

    The aim of this study was to examine breast density in relation to breast cancer specific survival and to assess if this potential association was modified by mode of detection. An additional aim was to study whether the established association between mode of detection and survival is modified by breast density. The study included 619 cases from a prospective cohort, The Malmö Diet and Cancer Study. Breast density estimated qualitatively, was analyzed in relation to breast cancer death, in non-symptomatic and symptomatic women, using Cox regression calculating hazard ratios (HR) with 95% confidence intervals. Adjustments were made in several steps for; diagnostic age, tumour size, axillary lymph node involvement, grade, hormone receptor status, body mass index (baseline), diagnostic period, use of hormone replacement therapy at diagnosis and mode of detection. Detection mode in relation to survival was analyzed stratified for breast density. Differences in HR following different adjustments were analyzed by Freedmans%. After adjustment for age and other prognostic factors, women with dense, as compared to fatty breasts, had an increased risk of breast cancer death, HR 2.56:1.07-6.11, with a statistically significant trend over density categories, p = 0.04. In the stratified analysis, the effect was less pronounced in non-symptomatic women, HR 2.04:0.49-8.49 as compared to symptomatic, HR 3.40:1.06-10.90. In the unadjusted model, symptomatic women had a higher risk of breast cancer death, regardless of breast density. Analyzed by Freedmans%, age, tumour size, lymph nodes, grade, diagnostic period, ER and PgR explained 55.5% of the observed differences in mortality between non-symptomatic and symptomatic cases. Additional adjustment for breast density caused only a minor change. High breast density at diagnosis may be associated with decreased breast cancer survival. This association appears to be stronger in women with symptomatic cancers but breast density could

  12. Performance of tablet disintegrants: impact of storage conditions and relative tablet density.

    Science.gov (United States)

    Quodbach, Julian; Kleinebudde, Peter

    2015-01-01

    Tablet disintegration can be influenced by several parameters, such as storage conditions, type and amount of disintegrant, and relative tablet density. Even though these parameters have been mentioned in the literature, the understanding of the disintegration process is limited. In this study, water uptake and force development of disintegrating tablets are analyzed, as they reveal underlying processes and interactions. Measurements were performed on dibasic calcium phosphate tablets containing seven different disintegrants stored at different relative humidities (5-97%), and on tablets containing disintegrants with different mechanisms of action (swelling and shape recovery), compressed to different relative densities. Disintegration times of tablets containing sodium starch glycolate are affected most by storage conditions, which is displayed in decreased water uptake and force development kinetics. Disintegration times of tablets with a swelling disintegrant are only marginally affected by relative tablet density, whereas the shape recovery disintegrant requires high relative densities for quick disintegration. The influence of relative tablet density on the kinetics of water uptake and force development greatly depends on the mechanism of action. Acquired data allows a detailed analysis of the influence of storage conditions and mechanisms of action on disintegration behavior.

  13. Relation between plasma plume density and gas flow velocity in atmospheric pressure plasma

    International Nuclear Information System (INIS)

    Yambe, Kiyoyuki; Taka, Shogo; Ogura, Kazuo

    2014-01-01

    We have studied atmospheric pressure plasma generated using a quartz tube, helium gas, and copper foil electrode by applying RF high voltage. The atmospheric pressure plasma in the form of a bullet is released as a plume into the atmosphere. To study the properties of the plasma plume, the plasma plume current is estimated from the difference in currents on the circuit, and the drift velocity is measured using a photodetector. The relation of the plasma plume density n plu , which is estimated from the current and the drift velocity, and the gas flow velocity v gas is examined. It is found that the dependence of the density on the gas flow velocity has relations of n plu ∝ log(v gas ). However, the plasma plume density in the laminar flow is higher than that in the turbulent flow. Consequently, in the laminar flow, the density increases with increasing the gas flow velocity

  14. Influence of relative density on the cyclic shear strength of sands

    Directory of Open Access Journals (Sweden)

    Arab A.

    2018-01-01

    Full Text Available This paper presents a laboratory study of the influence of relative density on the liquefaction potential of a soil. The study is based on undrained triaxial tests that were performed on samples with relative density Id = 0.15, 0.5 and 0.65. The article is composed of three parts. First, we present the materials and characteristics of the studied sands. the second part deals with the procedure and the device used. The third part studies the influence of the relative density on the liquefaction potential of the three sands (Hostun Rf, Chlef and Rass. This study also makes it possible to explore the influence of granulometry on the liquefaction potential. The results of the tests show that concordant results have been obtained which clearly show that the increase of the relative density leads to a significant improvement in the resistance to liquefaction of the sands. This effect is very significant when the initial relative density Id = 0.50 to Id = 0.65.

  15. Triton-3He relative and differential flows and the high density behavior of nuclear symmetry

    International Nuclear Information System (INIS)

    Yong, Gaochan; Li, Baoan; Chen, Liewen

    2010-01-01

    Using a transport model coupled with a phase-space coalescence after-burner we study the triton- 3 He relative and differential transverse flows in semi-central 132 Sn + 124 Sn reactions at a beam energy of 400 MeV/nucleon. We find that the triton- 3 He pairs carry interesting information about the density dependence of the nuclear symmetry energy. The t- 3 He relative flow can be used as a particularly powerful probe of the high-density behavior of the nuclear symmetry energy. (author)

  16. Narrative skills of children treated for brain tumours: The impact of tumour and treatment related variables on microstructure and macrostructure.

    Science.gov (United States)

    Docking, Kimberley; Munro, Natalie; Marshall, Tara; Togher, Leanne

    2016-01-01

    The narrative skills of children with brain tumours were examined. Influence of tumour location, radiotherapy, time post-treatment and presence of hydrocephalus was also investigated, as well as associations between narrative and language abilities. Seventeen children (aged 5;6-14;11) treated for brain tumour and their matched controls completed a narrative assessment and comprehensive language testing. Audio recorded narratives were analysed for microstructure and macrostructure elements. Between-group comparisons were conducted. Narrative elements were explored in association with tumour and treatment-related variables. Correlation analysis examined relationships between narrative scores and language test performance. While significant differences were not found between two groups of children across narrative elements, sub-group comparisons revealed marginal differences in macrostructure related to tumour location and hydrocephalus. Children treated with methods other than radiotherapy showed a significant increase in number of mazes in their narratives compared to children who received radiotherapy. Strong positive correlations also existed between narrative elements and language performance. Preliminary findings highlight the importance of investigating narrative abilities as part of a comprehensive language assessment. Macrostructure should be routinely examined where children are diagnosed with either posterior fossa tumour or hydrocephalus or have undergone surgery and/or chemotherapy for brain tumour.

  17. Relation between obesity and bone mineral density and vertebral fractures in Korean postmenopausal women.

    Science.gov (United States)

    Kim, Kyong-Chol; Shin, Dong-Hyuk; Lee, Sei-Young; Im, Jee-Aee; Lee, Duk-Chul

    2010-11-01

    The traditional belief that obesity is protective against osteoporosis has been questioned. Recent epidemiologic studies show that body fat itself may be a risk factor for osteoporosis and bone fractures. Accumulating evidence suggests that metabolic syndrome and the individual components of metabolic syndrome such as hypertension, increased triglycerides, and reduced high-density lipoprotein cholesterol are also risk factors for low bone mineral density. Using a cross sectional study design, we evaluated the associations between obesity or metabolic syndrome and bone mineral density (BMD) or vertebral fracture. A total of 907 postmenopausal healthy female subjects, aged 60-79 years, were recruited from woman hospitals in Seoul, South Korea. BMD, vetebral fracture, bone markers, and body composition including body weight, body mass index (BMI), percentage body fat, and waist circumference were measured. After adjusting for age, smoking status, alcohol consumption, total calcium intake, and total energy intake, waist circumference was negatively related to BMD of all sites (lumbar BMD p = 0.037, all sites of femur BMD p related to BMD of all sites (p related to femoral trochanter BMD (p = 0.0366) and was lower in the control group than the fracture group (p = 0.011). In contrast to the effect favorable body weight on bone mineral density, high percentage body fat and waist circumference are related to low BMD and a vertebral fracture. Some components of metabolic syndrome were related to BMD and a vertebral fracture.

  18. Microstructure and mechanical properties of hard zone in friction stir welded X80 pipeline steel relative to different heat input

    Energy Technology Data Exchange (ETDEWEB)

    Aydin, Hakan, E-mail: hakanay@uludag.edu.tr [Engineering and Architecture Faculty, Mechanical Engineering Department, Uludag University, 16059 Gorukle-Bursa (Turkey); Nelson, Tracy W. [Mechanical Engineering Department, Brigham Young University, 435 CTB, Provo, UT 84602 (United States)

    2013-12-01

    The study was conducted to investigate the microstructure and mechanical properties of the hard zone in friction stir welded X80 pipeline steel at different heat inputs. Microstructural analysis of the welds was carried out using optical microscopy, transmission electron microscopy, and microhardness. Heat input during friction stir welding process had a significant influence on the microstructure and mechanical properties in the hard zone along the advancing side of the weld nugget. Based on the results, the linear relationships between heat input and post-weld microstructures and mechanical properties in the hard zone of friction stir welded X80 steels were established. It can be concluded that with decrease in heat input the bainitic structure in the hard zone becomes finer and so hard zone strength increases.

  19. Microstructure and mechanical properties of hard zone in friction stir welded X80 pipeline steel relative to different heat input

    International Nuclear Information System (INIS)

    Aydin, Hakan; Nelson, Tracy W.

    2013-01-01

    The study was conducted to investigate the microstructure and mechanical properties of the hard zone in friction stir welded X80 pipeline steel at different heat inputs. Microstructural analysis of the welds was carried out using optical microscopy, transmission electron microscopy, and microhardness. Heat input during friction stir welding process had a significant influence on the microstructure and mechanical properties in the hard zone along the advancing side of the weld nugget. Based on the results, the linear relationships between heat input and post-weld microstructures and mechanical properties in the hard zone of friction stir welded X80 steels were established. It can be concluded that with decrease in heat input the bainitic structure in the hard zone becomes finer and so hard zone strength increases

  20. Local microstructure and flow stress in deformed metals

    DEFF Research Database (Denmark)

    Zhang, Xiaodan; Hansen, Niels; Nielsen, Chris Valentin

    2017-01-01

    The microstructure and flow stress of metals are related through many well-known strength-structure relationships based on structural parameters, where grain size and dislocation density are examples. In heterogeneous structures, the local stress and strain are important as they will affect...... the bulk properties. A microstructural method is presented which allows the local stress in a deformed metal to be estimated based on microstructural parameters determined by an EBSD analysis. These parameters are the average spacing of deformation introduced boundaries and the fraction of high angle...... boundaries. The method is demonstrated for two heterogeneous structures: (i) a gradient (sub)surface structure in steel deformed by shot peening; (ii) a heterogeneous structure introduced by friction between a tool and a workpiece of aluminum. Flow stress data are calculated based on the microstructural...

  1. Macular pigment optical density is related to serum lutein in retinitis pigmentosa

    Science.gov (United States)

    Purpose: To determine whether macular pigment optical density (MPOD) is related to the degree of cystoid macular edema (CME) in patients with retinitis pigmentosa. Methods: We measured MPOD with heterochromatic flicker photometry and central foveal retinal thickness with optical coherence tomography...

  2. Influence of the curve density relative electron in dosimetry clinic in treatments stereo tactics

    International Nuclear Information System (INIS)

    Moreno Saiz, C.; Benitez Villegas, E. M.; Casado Villalon, F. J.; Parra Osorio, V.; Bodineau Gil, C.; Garcia Pareja, S.

    2013-01-01

    The objective of this study is to analyze the difference between clinical dosimetry in the treatments with radiosurgery and stereotactic radiotherapy fractional obtained from the relative Electron density curve (Schneider 1996) tabulated and provided with the scanner's radiation therapy. (Author)

  3. RELATIVE AND ABSOLUTE DENSITY ESTIMATES OF LAND PLANARIANS (PLATYHELMINTHES, TRICLADIDA IN URBAN RAINFOREST PATCHES

    Directory of Open Access Journals (Sweden)

    FERNANDO CARBAYO

    Full Text Available ABSTRACT Land planarians (Platyhelminthes are likely important components of the soil cryptofauna, although relevant aspects of their ecology such as their density remain largely unstudied. We investigated absolute and relative densities of flatworms in three patches of secondary Brazilian Atlantic rainforest in an urban environment. Two methods of sampling were carried out, one consisting of 90 hours of active search in delimited plots covering 6,000 m² over a year, and the other consisting of leaf litter extraction from a 60 m² soil area, totaling 480-600 l leaf litter. We found 288 specimens of 16 species belonging to the genera Geobia, Geoplana, Issoca, Luteostriata, Obama, Paraba, Pasipha, Rhynchodemus, Xerapoa, and the exotic species Bipalium kewense and Dolichoplana striata. Specimens up to 10 mm long were mostly sampled only with the leaf litter extraction method. Absolute densities, calculated from data obtained with leaf litter extraction, ranged between 1.25 and 2.10 individuals m-2. These values are 30 to 161 times higher than relative densities, calculated from data obtained by active search. Since most common sampling method used in land planarian studies on species composition and faunal inventories is active search for a few hours in a locality, our results suggest that small species might be overlooked. It remains to be tested whether similar densities of this cryptofauna are also found in primary forests.

  4. Interspecific variation in tree seedlings establishment in canopy gaps in relation to tree density

    Energy Technology Data Exchange (ETDEWEB)

    Reader, R.J.; Bonser, S.P.; Duralia, T.E.; Bricker, B.D. [Guelph Univ., ON (Canada). Dept. of Botany

    1995-10-01

    We tested whether interspecific variation in tree seedling establishment in canopy gaps was significantly related to interspecific variation in tree density, for seven deciduous forest tree species (Quercus alba, Hamamelis virginiana, Acer rubrum, Sassafras albidum, Quercus rubra, Prunus serotina, Ostrya virginiana). For each species, seedling establishment was calculated as the difference in seedling density before experimental gap creation versus three years after gap creation. In each of the six experimentally-created gap types (33% or 66% removal of tree basal area from 0.01ha, 0.05ha or 0.20ha patches), differences in seedling establishment among species were significantly related to differences in their density in the tree canopy. A regression model with log{sub e} tree density as the independent variable accounted for between 93% and 98% of interspecific variation in seedling establishment. Our results provide empirical support for models of tree dynamics in gaps that assume seedling establishment depends on canopy tree density. 17 refs, 1 fig, 3 tabs

  5. Probing topological relations between high-density and low-density regions of 2MASS with hexagon cells

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Yongfeng [American Physical Society, San Diego, CA (United States); Xiao, Weike, E-mail: yongfeng.wu@maine.edu [Department of Astronautics Engineering, Harbin Institute of Technology, P.O. Box 345, Heilongjiang Province 150001 (China)

    2014-02-01

    We introduced a new two-dimensional (2D) hexagon technique for probing the topological structure of the universe in which we mapped regions of the sky with high and low galaxy densities onto a 2D lattice of hexagonal unit cells. We defined filled cells as corresponding to high-density regions and empty cells as corresponding to low-density regions. The numbers of filled cells and empty cells were kept the same by controlling the size of the cells. By analyzing the six sides of each hexagon, we could obtain and compare the statistical topological properties of high-density and low-density regions of the universe in order to have a better understanding of the evolution of the universe. We applied this hexagonal method to Two Micron All Sky Survey data and discovered significant topological differences between the high-density and low-density regions. Both regions had significant (>5σ) topological shifts from both the binomial distribution and the random distribution.

  6. A study of hydrogen environment effects on microstructure property behavior of NASA-23 alloy and related alloy systems

    International Nuclear Information System (INIS)

    Diwan, R.M.

    1990-01-01

    The influence of hydrogen on the tensile properties and ductility behavior of NASA-23 alloy were analyzed. NASA-23 and other referenced alloys in cast and hipped conditions were solution treated and aged under selected conditions and characterized using optical metallography, scanning electron microscopy, and electron microprobe analysis techniques. The yield strength of NASA-23 is not affected much by hydrogen under tensile tests carried at 5000 psig conditions; however, the ultimate strength and ductility properties are degraded. This implies that the physical mechanisms operating would be related to the plastic deformation process. The fracture surfaces characteristics of NASA-23 specimens tensile tested in hydrogen, helium, and air were also analyzed. These revealed surface cracks around specimen periphery with the fracture surface showing a combination of intergranular and transgranular modes of fracture. It is seen that the specimens charged in hydrogen seem to favor a more brittle fracture mode in comparison to air and helium charged specimens. The AMCC casting characterization program is to be analyzed for their hydrogen behavior. As a result of this program, the basic microstructural factors and fracture characteristics in some cases were analyzed

  7. A study of hydrogen environment effects on microstructure property behavior of NASA-23 alloy and related alloy systems

    Science.gov (United States)

    Diwan, Ravinder M.

    1990-01-01

    This work is part of the overall advanced main combustion chamber (AMCC) casting characterization program of the Materials and Processes Laboratory of the Marshall Space Flight Center. The influence of hydrogen on the tensile properties and ductility behavior of NASA-23 alloy were analyzed. NASA-23 and other referenced alloys in cast and hipped conditions were solution treated and aged under selected conditions and characterized using optical metallography, scanning electron microscopy, and electron microprobe analysis techniques. The yield strength of NASA-23 is not affected much by hydrogen under tensile tests carried at 5000 psig conditions; however, the ultimate strength and ductility properties are degraded. This implies that the physical mechanisms operating would be related to the plastic deformation process. The fracture surfaces characteristics of NASA-23 specimens tensile tested in hydrogen, helium, and air were also analyzed. These revealed surface cracks around specimen periphery with the fracture surface showing a combination of intergranular and transgranular modes of fracture. It is seen that the specimens charged in hydrogen seem to favor a more brittle fracture mode in comparison to air and helium charged specimens. The AMCC casting characterization program is to be analyzed for their hydrogen behavior. As a result of this program, the basic microstructural factors and fracture characteristics in some cases were analyzed.

  8. Evolution of microstructure and related optical properties of ZnO grown by atomic layer deposition

    Directory of Open Access Journals (Sweden)

    Adib Abou Chaaya

    2013-10-01

    Full Text Available A study of transmittance and photoluminescence spectra on the growth of oxygen-rich ultra-thin ZnO films prepared by atomic layer deposition is reported. The structural transition from an amorphous to a polycrystalline state is observed upon increasing the thickness. The unusual behavior of the energy gap with thickness reflected by optical properties is attributed to the improvement of the crystalline structure resulting from a decreasing concentration of point defects at the growth of grains. The spectra of UV and visible photoluminescence emissions correspond to transitions near the band-edge and defect-related transitions. Additional emissions were observed from band-tail states near the edge. A high oxygen ratio and variable optical properties could be attractive for an application of atomic layer deposition (ALD deposited ultrathin ZnO films in optical sensors and biosensors.

  9. Surface-plasmon dispersion relation for the inhomogeneous charge-density medium

    International Nuclear Information System (INIS)

    Harsh, O.K.; Agarwal, B.K.

    1989-01-01

    The surface-plasmon dispersion relation is derived for the plane-bounded electron gas when there is an inhomogeneous charge-density distribution in the plasma. The hydrodynamical model is used. Both cphi and dcphi/dx are taken to be continuous at the surface of the slab, where cphi is the scalar potential. The dispersion relation is compared with the theoretical works of Stern and Ferrell and of Harsh and Agarwal. It is also compared with the observations of Kunz. A dispersion relation for the volume-plasmon oscillations is derived which resembles the well-known relation of Bohm and Pines

  10. Micromagnetism and the microstructure of ferromagnetic solids

    CERN Document Server

    Kronmüller, Helmut

    2003-01-01

    Here is a fundamental introduction to microstructure magnetic property relations where microstructures on atomic, nano- and micrometer scales are considered. The authors demonstrate that outstanding magnetic properties require an optimization of microstructural properties where the microstructures in crystalline materials are point defects and dislocations as well as grain and phase boundaries. In amorphous alloys the type of microstructures on atomic scales are defined and used to describe intrinsic and extrinsic properties.

  11. Surface density: a new parameter in the fundamental metallicity relation of star-forming galaxies

    Science.gov (United States)

    Hashimoto, Tetsuya; Goto, Tomotsugu; Momose, Rieko

    2018-04-01

    Star-forming galaxies display a close relation among stellar mass, metallicity, and star formation rate (or molecular-gas mass). This is known as the fundamental metallicity relation (FMR) (or molecular-gas FMR), and it has a profound implication on models of galaxy evolution. However, there still remains a significant residual scatter around the FMR. We show here that a fourth parameter, the surface density of stellar mass, reduces the dispersion around the molecular-gas FMR. In a principal component analysis of 29 physical parameters of 41 338 star-forming galaxies, the surface density of stellar mass is found to be the fourth most important parameter. The new 4D fundamental relation forms a tighter hypersurface that reduces the metallicity dispersion to 50 per cent of that of the molecular-gas FMR. We suggest that future analyses and models of galaxy evolution should consider the FMR in a 4D space that includes surface density. The dilution time-scale of gas inflow and the star-formation efficiency could explain the observational dependence on surface density of stellar mass.

  12. Local energy equation for two-electron atoms and relation between kinetic energy and electron densities

    International Nuclear Information System (INIS)

    March, N.H.

    2002-08-01

    In early work, Dawson and March [J. Chem. Phys. 81, 5850 (1984)] proposed a local energy method for treating both Hartree-Fock and correlated electron theory. Here, an exactly solvable model two-electron atom with pure harmonic interactions is treated in its ground state in the above context. A functional relation between the kinetic energy density t(r) at the origin r=0 and the electron density p(r) at the same point then emerges. The same approach is applied to the Hookean atom; in which the two electrons repel with Coulombic energy e 2 /r 12 , with r 12 the interelectronic separation, but are still harmonically confined. Again the kinetic energy density t(r) is the focal point, but now generalization away from r=0 is also effected. Finally, brief comments are added about He-like atomic ions in the limit of large atomic number. (author)

  13. Relation among serum and tissue concentrations of lutein and zeaxanthin and macular pigment density.

    Science.gov (United States)

    Johnson, E J; Hammond, B R; Yeum, K J; Qin, J; Wang, X D; Castaneda, C; Snodderly, D M; Russell, R M

    2000-06-01

    Lutein and zeaxanthin are the only carotenoids in the macular region of the retina (referred to as macular pigment [MP]). Foods that are rich in lutein and zeaxanthin can increase MP density. Response to dietary lutein and zeaxanthin in other tissues has not been studied. The objective of this study was to examine tissue responses to dietary lutein and zeaxanthin and relations among tissues in lutein and zeaxanthin concentrations. Seven subjects consumed spinach and corn, which contain lutein and zeaxanthin, with their daily diets for 15 wk. At 0, 4, 8, and 15 wk and 2 mo after the study, serum, buccal mucosa cells, and adipose tissue were analyzed for carotenoids, and MP density was measured. Serum and buccal cell concentrations of lutein increased significantly from baseline during dietary modification. Serum zeaxanthin concentrations were greater than at baseline only at 4 wk, whereas buccal cell and adipose tissue concentrations of zeaxanthin did not change. Adipose tissue lutein concentrations peaked at 8 wk. Changes in adipose tissue lutein concentration were inversely related to the changes in MP density, suggesting an interaction between adipose tissue and retina in lutein metabolism. To investigate the possibility of tissue interactions, we examined cross-sectional relations among serum, tissue, and dietary lutein concentrations, anthropometric measures, and MP density in healthy adults. Significant negative correlations were found between adipose tissue lutein concentrations and MP for women, but a significant positive relation was found for men. Sex differences in lutein metabolism may be an important factor in tissue interactions and in determining MP density.

  14. Relations between sinkhole density and anthropogenic contaminants in selected carbonate aquifers in the eastern United States

    Science.gov (United States)

    Lindsey, Bruce D.; Katz, Brian G.; Berndt, Marian P.; Ardis, Ann F.; Skach, Kenneth A.

    2009-01-01

    The relation between sinkhole density and water quality was investigated in seven selected carbonate aquifers in the eastern United States. Sinkhole density for these aquifers was grouped into high (>25 sinkholes/100 km2), medium (1–25 sinkholes/100 km2), or low (2) categories using a geographical information system that included four independent databases covering parts of Alabama, Florida, Missouri, Pennsylvania, and Tennessee. Field measurements and concentrations of major ions, nitrate, and selected pesticides in samples from 451 wells and 70 springs were included in the water-quality database. Data were collected as a part of the US Geological Survey (USGS) National Water-Quality Assessment (NAWQA) Program. Areas with high and medium sinkhole density had the greatest well depths and depths to water, the lowest concentrations of total dissolved solids and bicarbonate, the highest concentrations of dissolved oxygen, and the lowest partial pressure of CO2 compared to areas with low sinkhole density. These chemical indicators are consistent conceptually with a conduit-flow-dominated system in areas with a high density of sinkholes and a diffuse-flow-dominated system in areas with a low density of sinkholes. Higher cave density and spring discharge in Pennsylvania also support the concept that the high sinkhole density areas are dominated by conduit-flow systems. Concentrations of nitrate-N were significantly higher (p sinkhole density than in low sinkhole-density areas; when accounting for the variations in land use near the sampling sites, the high sinkhole-density area still had higher concentrations of nitrate-N than the low sinkhole-density area. Detection frequencies of atrazine, simazine, metolachlor, prometon, and the atrazine degradate deethylatrazine indicated a pattern similar to nitrate; highest pesticide detections were associated with high sinkhole-density areas. These patterns generally persisted when analyzing the detection frequency by land

  15. [Dietary patterns in college freshmen and its relation to bone mineral density].

    Science.gov (United States)

    Wang, Sufang; Mu, Min; Zhao, Yan; Wang, Xiaoqin; Shu, Long; Li, Qingyan; Li, Yingchun

    2012-07-01

    In order to investigate the bone density of freshmen, and to analyze the association between dietary pattern and bone mineral density (BMD). A questionnaire survey on the situation of dietary pattern was conducted in 1414 freshmen. Effective dietary survey questionnaires and bone mineral density measurements were completed for 1319 participants. Bone mass was assessed by using an Ultrasound Bone Densitometer on the right calcaneus (CM-200, Furuno Electric Corporation, Japan), and the speed of sound (SOS, m/s) was used as an indicator for bone density. Factor analysis with varimax rotation was used to identify the dietary patterns. After adjusting for confounders, covariance with Bonferroni's was used to further examine the associations between dietary patterns and bone mineral density (BMD). (1) Four major dietary patterns were noticed. Western food pattern (high consumption in hamburger, fried food, nuts, biscuit, chocolate, cola, coffee, sugars). Animal protein pattern (high consumption in pork, mutton, beef, poultry meat, animal liver). Calcium pattern (high consumption in fresh fruits, eggs, fish and shrimps, kelp laver and sea fish, milk and dairy products, beans and bean products). Traditional Chinese pattern (high consumption in rice and grain, fresh fruits, fresh vegetables, pork). (2) No association was observed between the western food pattern and bone mineral density. High animal protein pattern showed lower SOS value compared with low animal protein pattern. High calcium pattern showed higher SOS value compared with low calcium pattern. High traditional Chinese pattern showed higher SOS value compared with the low traditional Chinese pattern. Dietary patterns are closely related with bone mineral density (BMD) of freshmen.

  16. Size-density relations in dark clouds: Non-LTE effects

    International Nuclear Information System (INIS)

    Maloney, P.

    1986-01-01

    One of the major goals of molecular astronomy has been to understand the physics and dynamics of dense interstellar clouds. Because the interpretation of observations of giant molecular clouds is complicated by their very complex structure and the dynamical effects of star formation, a number of studies have concentrated on dark clouds. Leung, Kutner and Mead (1982) (hereafter LKM) and Myers (1983), in studies of CO and NH 3 emission, concluded that dark clouds exhibit significant correlations between linewidth and cloud radius of the form delta v varies as R(0.5) and between mean density and radius of the form n varies as R(-1), as originally suggested by Larson (1981). This result suggests that these objects are in virial equilibrium. However, the mean densities inferred from the CO data of LKM are based on an local thermodynamic equilibrium (LTE) analysis of their 13CO data. At the very low mean densities inferred by LKM for the larger clouds in their samples, the assumption of LTE becomes very questionable. As most of the range in R in the density-size correlation comes from the clouds observed in CO, it seems worthwhile to examine how non-LTE effects will influence the derived densities. Microturbulent models of inhomogeneous clouds of varying central concentration with the linewidth-size and mean density-size relations found by Myers show sub-thermal excitation of the 13CO line in the larger clouds, with the result that LTE analysis considerbly underestimates the actual column density. A more general approach which doesn't require detailed modeling of the clouds is to consider whether the observed T/sub R/*(13CO)/T/sub R/*(12CO) ratios in the clouds studied by LKM are in the range where the LTE-derived optical depths be seriously in error due to sub-thermal excitation of the 13CO molecule

  17. Energy and nutrient density of foods in relation to their carbon footprint.

    Science.gov (United States)

    Drewnowski, Adam; Rehm, Colin D; Martin, Agnes; Verger, Eric O; Voinnesson, Marc; Imbert, Philippe

    2015-01-01

    A carbon footprint is the sum of greenhouse gas emissions (GHGEs) associated with food production, processing, transporting, and retailing. We examined the relation between the energy and nutrient content of foods and associated GHGEs as expressed as g CO2 equivalents. GHGE values, which were calculated and provided by a French supermarket chain, were merged with the Composition Nutritionnelle des Aliments (French food-composition table) nutrient-composition data for 483 foods and beverages from the French Agency for Food, Environmental and Occupational Health and Safety. Foods were aggregated into 34 food categories and 5 major food groups as follows: meat and meat products, milk and dairy products, frozen and processed fruit and vegetables, grains, and sweets. Energy density was expressed as kcal/100 g. Nutrient density was determined by using 2 alternative nutrient-density scores, each based on the sum of the percentage of daily values for 6 or 15 nutrients, respectively. The energy and nutrient densities of foods were linked to log-transformed GHGE values expressed per 100 g or 100 kcal. Grains and sweets had lowest GHGEs (per 100 g and 100 kcal) but had high energy density and a low nutrient content. The more-nutrient-dense animal products, including meat and dairy, had higher GHGE values per 100 g but much lower values per 100 kcal. In general, a higher nutrient density of foods was associated with higher GHGEs per 100 kcal, although the slopes of fitted lines varied for meat and dairy compared with fats and sweets. Considerations of the environmental impact of foods need to be linked to concerns about nutrient density and health. The point at which the higher carbon footprint of some nutrient-dense foods is offset by their higher nutritional value is a priority area for additional research. © 2015 American Society for Nutrition.

  18. Density and relative frequency effects on competitive interactions and resource use in pea–barley intercrops

    DEFF Research Database (Denmark)

    Hauggaard-Nielsen, H.; Andersen, H.K.; Jørnsgaard, B.

    2006-01-01

    or specific grain yield composition are wanted. Keywords: Competition dynamics; Grain quality; Hordeum vulgare; Intercropping; Nitrogen use; Organic farming; Pisum sativum; Weeds; Yield Abbreviations: IC, mixed intercropping; LER, land equivalent ratio; N, nitrogen; REIc, relative efficiency index; SC, sole...... not increase its reliance on atmospheric nitrogen fixation compared to the pea sole crop. With respect to soil nitrogen uptake there were no effect of plant density but a strong effect of the relative frequency of pea in the intercrop, the greater the proportion the lower the uptake. Changes in the competitive...... and tillering ability of barley are seen as likely explanations of lower weed load in the barley dominated crop treatments. This study points at the potential of employing density and relative crop frequency as "regulators" when specific intercrop objectives such as increased competitiveness towards weeds...

  19. Dispersion relation and Landau damping of waves in high-energy density plasmas

    International Nuclear Information System (INIS)

    Zhu Jun; Ji Peiyong

    2012-01-01

    We present a theoretical investigation on the propagation of electromagnetic waves and electron plasma waves in high energy density plasmas using the covariant Wigner function approach. Based on the covariant Wigner function and Dirac equation, a relativistic quantum kinetic model is established to describe the physical processes in high-energy density plasmas. With the zero-temperature Fermi–Dirac distribution, the dispersion relation and Landau damping of waves containing the relativistic quantum corrected terms are derived. The relativistic quantum corrections to the dispersion relation and Landau damping are analyzed by comparing our results with those obtained in classical and non-relativistic quantum plasmas. We provide a detailed discussion on the Landau damping obtained in classical plasmas, non-relativistic Fermi plasmas and relativistic Fermi plasmas. The contributions of the Bohm potential, the Fermi statistics pressure and relativistic effects to the dispersion relation and Landau damping of waves are quantitatively calculated with real plasma parameters. (paper)

  20. Relating the baryon asymmetry to the thermal relic dark matter density

    International Nuclear Information System (INIS)

    McDonald, John

    2011-01-01

    We present a generic framework, baryomorphosis, which modifies the baryon asymmetry to be naturally of the order of a typical thermal relic weakly interacting massive particle (WIMP) density. We consider a simple scalar-based model to show how this is possible. This model introduces a sector in which a large initial baryon asymmetry is injected into particles ('annihilons'), φ B , φ-circumflex B , of mass ∼100 GeV-1 TeV. φ B φ-circumflex B annihilations convert the initial φ B , φ-circumflex B asymmetry to a final asymmetry with a thermal relic WIMP-like density. This subsequently decays to a conventional baryon asymmetry whose magnitude is naturally related to the density of thermal relic WIMP dark matter. In this way the two coincidences of baryons and dark matter, i.e. why their densities are similar to each other and why they are both similar to a WIMP thermal relic density (the 'WIMP miracle'), may be understood. The model may be tested by the production of annihilons at colliders.

  1. Generalization of the existing relations between microstructure and yield stress from ferrite-pearlite to high strength steels

    Energy Technology Data Exchange (ETDEWEB)

    Iza-Mendia, A., E-mail: aiza@ceit.es [CEIT and Tecnun (University of Navarra), Manuel de Lardizabal 15, 20018 Donostia-San Sebastian, Basque Country (Spain); Gutierrez, I. [CEIT and Tecnun (University of Navarra), Manuel de Lardizabal 15, 20018 Donostia-San Sebastian, Basque Country (Spain)

    2013-01-20

    A series of available equations allows the yield and the tensile strength of low carbon ferrite-pearlite microstructures to be expressed as a function of the optical grain size, steel composition and interstitials in solution. Over the years, as the complexity of steel microstructures has increased, some additional terms have been added to account for precipitation and forest dislocation contributions. In theory, this opens the door for an extension of these equations to bainitic microstructures. Nevertheless, there is a series of difficulties that needs to be overcome in order to improve prediction accuracy. In the present work, different microstructures (ferrite-pearlite, bainite, quenched, and quenched and tempered) were produced and tension tested in a C-Mn-Nb steel. Optical microscopy and EBSD (Electron Back Scattered Diffraction) were applied and the results were compared as a function of the tolerance angle. Based on this work, an adaptation to Pickering's equation is proposed, including its extension to other microstructures rather than ferrite-pearlite.

  2. A local leaky-box model for the local stellar surface density-gas surface density-gas phase metallicity relation

    Science.gov (United States)

    Zhu, Guangtun Ben; Barrera-Ballesteros, Jorge K.; Heckman, Timothy M.; Zakamska, Nadia L.; Sánchez, Sebastian F.; Yan, Renbin; Brinkmann, Jonathan

    2017-07-01

    We revisit the relation between the stellar surface density, the gas surface density and the gas-phase metallicity of typical disc galaxies in the local Universe with the SDSS-IV/MaNGA survey, using the star formation rate surface density as an indicator for the gas surface density. We show that these three local parameters form a tight relationship, confirming previous works (e.g. by the PINGS and CALIFA surveys), but with a larger sample. We present a new local leaky-box model, assuming star-formation history and chemical evolution is localized except for outflowing materials. We derive closed-form solutions for the evolution of stellar surface density, gas surface density and gas-phase metallicity, and show that these parameters form a tight relation independent of initial gas density and time. We show that, with canonical values of model parameters, this predicted relation match the observed one well. In addition, we briefly describe a pathway to improving the current semi-analytic models of galaxy formation by incorporating the local leaky-box model in the cosmological context, which can potentially explain simultaneously multiple properties of Milky Way-type disc galaxies, such as the size growth and the global stellar mass-gas metallicity relation.

  3. Impedance/thermally stimulated depolarization current and microstructural relations at interfaces in degraded perovskite dielectrics

    Science.gov (United States)

    Liu, Wei-En

    temperatures due to trapped charges. It is known that leakage is often controlled by Poole-Frankel conduction mechanisms in Ta2O5 electrolytic capacitors. It is determined through I-V measurements that the leakage current indeed follows the Poole-Frenkel conduction characteristic under high field. A parallel TSDC study also confirms at high field and high temperature trapped charge phenomenon. Through the use of TSDC, a new high voltage Poole--Frenkel mechanism at highest field range, >64V, in this study was discovered. It is concluded that TSDC is one of best techniques for capacitor characterization, and recommended other TSDC methods that could be extended to enhance our understanding of structure-property-processing relations in capacitor characterization. (Abstract shortened by UMI.)

  4. Microstructural modelling of nuclear graphite using multi-phase models

    International Nuclear Information System (INIS)

    Berre, C.; Fok, S.L.; Marsden, B.J.; Mummery, P.M.; Marrow, T.J.; Neighbour, G.B.

    2008-01-01

    This paper presents a new modelling technique using three-dimensional multi-phase finite element models in which meshes representing the microstructure of thermally oxidised nuclear graphite were generated from X-ray micro-tomography images. The density of the material was related to the image greyscale using Beer-Lambert's law, and multiple phases could thus be defined. The local elastic and non-linear properties of each phase were defined as a function of density and changes in Young's modulus, tensile and compressive strength with thermal oxidation were calculated. Numerical predictions compared well with experimental data and with other numerical results obtained using two-phase models. These models were found to be more representative of the actual microstructure of the scanned material than two-phase models and, possibly because of pore closure occurring during compression, compressive tests were also predicted to be less sensitive to the microstructure geometry than tensile tests

  5. Absolute and relative densities of fast-food versus other restaurants in relation to weight status: Does restaurant mix matter?

    Science.gov (United States)

    Polsky, Jane Y; Moineddin, Rahim; Dunn, James R; Glazier, Richard H; Booth, Gillian L

    2016-01-01

    Given the continuing epidemic of obesity, policymakers are increasingly looking for levers within the local retail food environment as a means of promoting healthy weights. To examine the independent and joint associations of absolute and relative densities of restaurants near home with weight status in a large, urban, population-based sample of adults. We studied 10,199 adults living in one of four cities in southern Ontario, Canada, who participated in the Canadian Community Health Survey (cycles 2005, 2007/08, 2009/10). Multivariate models assessed the association of weight status (obesity and body mass index) with absolute densities (numbers) of fast-food, full-service and other restaurants, and the relative density (proportion) of fast-food restaurants (FFR) relative to all restaurants within ~10-minute walk of residential areas. Higher numbers of restaurants of any type were inversely related to excess weight, even in models adjusting for a range of individual covariates and area deprivation. However, these associations were no longer significant after accounting for higher walkability of areas with high volumes of restaurants. In contrast, there was a direct relationship between the proportion of FFR relative to all restaurants and excess weight, particularly in areas with high volumes of FFR (e.g., odds ratio for obesity=2.55 in areas with 5+ FFR, 95% confidence interval: 1.55-4.17, across the interquartile range). Policies aiming to promote healthy weights that target the volume of certain retail food outlets in residential settings may be more effective if they also consider the relative share of outlets serving more and less healthful foods. Copyright © 2015 Elsevier Inc. All rights reserved.

  6. Size-density relations in dark clouds: Non-LTE effects

    Science.gov (United States)

    Maloney, P.

    1986-01-01

    One of the major goals of molecular astronomy has been to understand the physics and dynamics of dense interstellar clouds. Because the interpretation of observations of giant molecular clouds is complicated by their very complex structure and the dynamical effects of star formation, a number of studies have concentrated on dark clouds. Leung, Kutner and Mead (1982) (hereafter LKM) and Myers (1983), in studies of CO and NH3 emission, concluded that dark clouds exhibit significant correlations between linewidth and cloud radius of the form delta v varies as R(0.5) and between mean density and radius of the form n varies as R(-1), as originally suggested by Larson (1981). This result suggests that these objects are in virial equilibrium. However, the mean densities inferred from the CO data of LKM are based on an local thermodynamic equilibrium (LTE) analysis of their 13CO data. At the very low mean densities inferred by LKM for the larger clouds in their samples, the assumption of LTE becomes very questionable. As most of the range in R in the density-size correlation comes from the clouds observed in CO, it seems worthwhile to examine how non-LTE effects will influence the derived densities. One way to assess the validity of LTE-derived densities is to construct cloud models and then to interpret them in the same way as the observed data. Microturbulent models of inhomogeneous clouds of varying central concentration with the linewidth-size and mean density-size relations found by Myers show sub-thermal excitation of the 13CO line in the larger clouds, with the result that LTE analysis considerbly underestimates the actual column density. A more general approach which doesn't require detailed modeling of the clouds is to consider whether the observed T sub R*(13CO)/T sub R*(12CO) ratios in the clouds studied by LKM are in the range where the LTE-derived optical depths (and hence column densities) can be seriously in error due to sub-thermal excitation of the 13CO

  7. Process Optimization and Microstructure Characterization of Ti6Al4V Manufactured by Selective Laser Melting

    Science.gov (United States)

    junfeng, Li; zhengying, Wei

    2017-11-01

    Process optimization and microstructure characterization of Ti6Al4V manufactured by selective laser melting (SLM) were investigated in this article. The relative density of sampled fabricated by SLM is influenced by the main process parameters, including laser power, scan speed and hatch distance. The volume energy density (VED) was defined to account for the combined effect of the main process parameters on the relative density. The results shown that the relative density changed with the change of VED and the optimized process interval is 55˜60J/mm3. Furthermore, compared with laser power, scan speed and hatch distance by taguchi method, it was found that the scan speed had the greatest effect on the relative density. Compared with the microstructure of the cross-section of the specimen at different scanning speeds, it was found that the microstructures at different speeds had similar characteristics, all of them were needle-like martensite distributed in the β matrix, but with the increase of scanning speed, the microstructure is finer and the lower scan speed leads to coarsening of the microstructure.

  8. Relation microstructure-propriétés mécaniques d'un acier martensitique inoxydable

    Directory of Open Access Journals (Sweden)

    Badinier Guillaume

    2013-11-01

    Full Text Available The relationship between microstructure and mechanical properties of MaX (1.4006 martensitic stainless steel has been studied. Optical microscopy was used to characterize the microstructure and the volume fraction of retained ferrite was measured by image analysis. Mechanical properties were measured in uni-axial tensile testing and a composite model has been developed to capture the effect of both the retained ferrite and the carbon content of the martensitic phase. First results show a reasonable correlation between the experimental stress-strain curves and the model. Results are discussed in view of a previous study on plain martensitic carbon steels.

  9. Age-related decrements in bone mineral density in women over 65

    Science.gov (United States)

    Steiger, P.; Cummings, S. R.; Black, D. M.; Spencer, N. E.; Genant, H. K.

    1992-01-01

    Age-related changes in bone density contribute to the risk of fractures. To describe the relationship between age and bone mass in elderly women, we studied a large cohort of women over age 65 years who were recruited from population-based lists in four cities in the United States. Bone density in g/cm2 was measured by single-photon absorptiometry (SPA) and dual x-ray absorptiometry (DXA) at the distal and proximal radius, the calcaneus, the lumbar spine, and the proximal femur. Centralized data collection was used to control data quality and consistency. We found a strong inverse relationship between bone density and age for most sites. Decrements in bone density between women aged 65-69 years and women 85 years and older exceeded 16% in all regions except the spine, where the difference between the two age groups was 6%. Ward's triangle and the calcaneus exhibited the largest decrements, with 26 and 21%, respectively. The estimates of annual changes in bone mineral density by linear regression at sites other than the spine ranged from -0.82% at the femoral neck and trochanter to -1.30% at Ward's triangle. Correlations between the different regions ranged from r = 0.51 between the proximal radius and Ward's triangle to r = 0.66 between the distal radius and calcaneus. We conclude that the inverse relationship between age and bone mass measured by absorptiometry techniques in white women continues into the ninth decade of life. The relationship is strongest for bone density of Ward's triangle and the calcaneus and weakest for the spine.

  10. Thermal Conductivity of Human Bone in Cryoprobe Freezing as Related to Density.

    Science.gov (United States)

    Walker, Kyle E; Baldini, Todd; Lindeque, Bennie G

    2017-03-01

    Cryoprobes create localized cell destruction through freezing. Bone is resistant to temperature flow but is susceptible to freezing necrosis at warmer temperatures than tumor cells. Few studies have determined the thermal conductivity of human bone. No studies have examined conductivity as related to density. The study goal was to examine thermal conductivity in human bone while comparing differences between cancellous and cortical bone. An additional goal was to establish a relationship between bone density and thermal conductivity. Six knee joints from 5 cadavers were obtained. The epiphyseal region was sliced in half coronally prior to inserting an argon-circulating cryoprobe directed away from the joint line. Thermistor thermometers were placed perpendicularly at measured increments, and the freezing cycle was recorded until steady-state conditions were achieved. For 2 cortical samples, the probe was placed intramedullary in metaphyseal samples and measurements were performed radially from the central axis of each sample. Conductivity was calculated using Fournier's Law and then plotted against measured density of each sample. Across samples, density of cancellous bone ranged from 0.86 to 1.38 g/mL and average thermal conductivity ranged between 0.404 and 0.55 W/mK. Comparatively, cortical bone had a density of 1.70 to 1.86 g/mL and thermal conductivity of 0.0742 to 0.109 W/mK. A strong 2-degree polynomial correlation was seen (R 2 =0.8226, P<.001). Bone is highly resistant to temperature flow. This resistance varies and inversely correlates strongly with density. This information is clinically relevant to maximize tumor ablation while minimizing morbidity through unnecessary bone loss and damage to surrounding structures. [Orthopedics. 2017; 40(2):90-94.]. Copyright 2016, SLACK Incorporated.

  11. Epizootic of sarcoptic mange in raccoon dogs (Nyctereutes procyonoides) in relation to population density.

    Science.gov (United States)

    Sugiura, Natsuko; Doi, Kandai; Kato, Takuya; Morita, Tatsushi; Hayama, Shin-Ichi

    2018-03-30

    To examine outbreaks of mange in raccoon dogs (Nyctereutes procyonoides) with respect to population density, we analyzed camera trap videos, and isolated mites from raccoon dog carcasses. In a camera trapping survey, we categorized the skin condition of raccoon dogs, and used a number of independent videos to calculate the relative abundance index (RAI). The RAI of raccoon dogs with alopecia increased following an increase in the RAI of those without alopecia. Among 27 raccoon dog carcasses, 12 showed mange-compatible skin lesions. Sarcoptes scabiei was isolated from 11 of these raccoon dogs, indicating that sarcoptic mange was endemic in our study area. Therefore, a high relative population density may be a factor underlying epizootics of sarcoptic mange in raccoon dogs.

  12. TRACING THE STAR-FORMATION-DENSITY RELATION TO z {approx} 2

    Energy Technology Data Exchange (ETDEWEB)

    Quadri, Ryan F.; Williams, Rik J. [Carnegie Observatories, Pasadena, CA 91101 (United States); Franx, Marijn; Hildebrandt, Hendrik, E-mail: quadri@obs.carnegiescience.edu [Leiden Observatory, Leiden University, NL-2300 RA Leiden (Netherlands)

    2012-01-10

    Recent work has shown that the star formation (SF) density relation-in which galaxies with low SF rates are preferentially found in dense environments-is still in place at z {approx} 1, but the situation becomes less clear at higher redshifts. We use mass-selected samples drawn from the UKIDSS Ultra-Deep Survey to show that galaxies with quenched SF tend to reside in dense environments out to at least z {approx} 1.8. Over most of this redshift range we are able to demonstrate that this SF-density relation holds even at fixed stellar mass. The environmental quenching of SF appears to operate with similar efficiency on all galaxies regardless of stellar mass. Nevertheless, the environment plays a greater role in the buildup of the red sequence at lower masses, whereas other quenching processes dominate at higher masses. In addition to a statistical analysis of environmental densities, we investigate a cluster at z = 1.6, and show that the central region has an elevated fraction of quiescent objects relative to the field. Although the uncertainties are large, the environmental quenching efficiency in this cluster is consistent with that of galaxy groups and clusters at z {approx} 0. In this work we rely on photometric redshifts and describe some of the pitfalls that large redshift errors can present.

  13. Silicate melts density, buoyancy relations and the dynamics of magmatic processes in the upper mantle

    Science.gov (United States)

    Sanchez-Valle, Carmen; Malfait, Wim J.

    2016-04-01

    with results from ab initio calculations. The density model has been applied to examine the mineral-melt buoyancy relations at depth and the implications of these results for the dynamics of magma chambers, crystal settling and the stability and mobility of magmas in the upper mantle will be discussed.

  14. Age-related changes of vertical and horizontal lumbar vertebral trabecular 3D bone microstructure is different in women and men.

    Science.gov (United States)

    Thomsen, Jesper Skovhus; Niklassen, Andreas Steenholt; Ebbesen, Ebbe Nils; Brüel, Annemarie

    2013-11-01

    The study presents a 3D method for subdividing a trabecular network into horizontal and vertical oriented bone. This method was used to investigate the age related changes of the bone volume fraction and thickness of horizontal and vertical trabeculae in human lumbar vertebral bone estimated with unbiased 3D methods in women and men over a large age-range. The study comprised second lumbar vertebral body bone samples from 40 women (aged 21.7-96.4years, median 56.6years) and 39 men (aged 22.6-94.6years, median 55.6years). The bone samples were μCT scanned and the 3D microstructure was quantified. A voxel based algorithm inspecting the local neighborhood is presented and used to segment the trabecular network into horizontal and vertical oriented bone. For both women and men BV/TV decreased significantly with age, Tb.Th* was independent of age, while SMI increased significantly with age. Vertical (BV.vert/TV) and horizontal (BV.horz/TV) bone volume fraction decreased significantly with age for both sexes. BV.vert/TV decreased significantly faster with age for women than for men. Vertical (Tb.Th*.vert) and horizontal (Tb.Th*.horz) trabecular thickness were independent of age, while Tb.Th*.horz/Tb.Th*.vert decreased significantly with age for both sexes. Additionally, the 95th percentile of the trabecular thickness distribution increased significantly with age for vertical trabeculae in women, whereas it was independent of age in men. In conclusion, we have shown that vertical and horizontal oriented bone density decreases with age in both women and men, and that vertical oriented bone is lost more quickly in women than in men. Furthermore, vertical and horizontal trabecular thickness were independent of age, whereas the horizontal to vertical trabecular thickness ratio decreased significantly with age indicating a relatively more pronounced thinning of horizontal trabeculae. Finally, the age-related loss of trabecular elements appeared to result in a compensatory

  15. The effects of HIP processing on microstructure and phase relations in. alpha. sub 2 -base titanium aluminides

    Energy Technology Data Exchange (ETDEWEB)

    Saqib, M. (Dept. of Mechanical and Materials Engineering, Wright State Univ., Dayton, OH (United States)); Apgar, L.S.; Eylon, D. (Graduate Materials Engineering, Univ. of Dayton, OH (United States)); Weiss, I. (Dept. of Mechanical and Materials Engineering, Wright State Univ., Dayton, OH (United States))

    1992-05-30

    Cast {alpha}{sub 2}-base alloy (Ti-25Al-10Nb-3V-1Mo, at.%) underwent hot isostatic pressing (HIP) at temperatures ranging from 925 to 1125degC and pressures of 100-270 MPa. Effects of temperature and pressure during HIP, on microstructure and volume fraction of the phases present, were investigated. Microstructural characterization was carried out using optical microscopy and transmission electron microscopy. The phases present were identified using selected area and convergent beam electron diffraction. Volume fraction of the phases was determined using X-ray diffraction. Optimum refinement in the microstructure was obtained following HIP at 1020degC/262 MPa/6 h. The volume fraction of the B2 phase increased from 12% in the as-cast condition to 45% following HIP at 982degC/262 MPa/6 h. Experiments on forged Ti-25Al-10Nb-3V-1Mo alloy demonstrated that changes in volume fraction of the phases owing to HIP was applicable for cast as well as forged material. Sharp decrease in the volume fraction of the B2 phase was observed when as-HIP materials were aged at elevated temperature. Possible mechanisms of these changes in the phase stability and microstructure are discussed. (orig.).

  16. Progranulin concentration in relation to bone mineral density among obese individuals.

    Science.gov (United States)

    Milajerdi, Alireza; Maghbooli, Zhila; Mohammadi, Farzad; Hosseini, Banafsheh; Mirzaei, Khadijeh

    2018-01-01

    Adipose tissue, particularly visceral adipose tissue, secretes a variety of cytokines, among which progranulin is a glycoprotein related to the immune system. Along with other secreted proteins, progranulin may be associated with bone mineral density. The aim of this study was to find out whether there are associations between the progranulin and bone mineral density among obese people. This cross-sectional study was conducted on 244 obese participants (aged 22-52). Serum progranulin, high sensitive C-reactive protein, oxidised-low dencity lipoprotein, tumor necrosis factor-α, parathormone, vitamin D, and interleukins of 1 β, 4, 6, 10, 13, and 17 concentrations were measured. Anthropometric measurements, body composition and bone mineral density were also assessed. Serum progranulin was directly associated with interleukin-6 and interleukin-1β, while it had a negative association with interleukin-17 and tumor necrosis factor-α. We also observed a statistically significant direct association between progranulin concentration and visceral fat, abdominal fat, waist, abdominal and hip circumferences, hip T-score, and Z-score and T-score for the lumbar region. A partial correlation test has also shown a significant positive correlation regarding serum progranulin and the hip Z-score. Moreover, progranulin level is inversely associated with ospteopenia (P = 0.04 and CI: 0.17,0.96). Our study revealed that central obesity may be related to increased progranulin concentration. In addition, progranulin concentration was directly related to bone formation parameters, which indicates the protective effects of progranulin on bone density. Further studies are needed to clarify the exact mechanisms underlying these associations.

  17. Change in alcohol outlet density and alcohol-related harm to population health (CHALICE

    Directory of Open Access Journals (Sweden)

    Fone David

    2012-06-01

    Full Text Available Abstract Background Excess alcohol consumption has serious adverse effects on health and violence-related harm. In the UK around 37% of men and 29% of women drink to excess and 20% and 13% report binge drinking. The potential impact on population health from a reduction in consumption is considerable. One proposed method to reduce consumption is to reduce availability through controls on alcohol outlet density. In this study we investigate the impact of a change in the density of alcohol outlets on alcohol consumption and alcohol-related harms to health in the community. Methods/Design A natural experiment of the effect of change in outlet density between 2005–09, in Wales, UK; population 2.4 million aged 16 years and over. Data on outlets are held by the 22 local authorities in Wales under The Licensing Act 2003. The study outcomes are change in (1 alcohol consumption using data from annual Welsh Health Surveys, (2 alcohol-related hospital admissions using the Patient Episode Database for Wales, (3 Accident & Emergency department attendances between midnight–6am, and (4 alcohol-related violent crime against the person, using Police data. The data will be anonymously record-linked within the Secure Anonymised Information Linkage Databank at individual and 2001 Census Lower Super Output Area levels. New methods of network analysis will be used to estimate outlet density. Longitudinal statistical analysis will use (1 multilevel ordinal models of consumption and logistic models of admissions and Accident & Emergency attendance as a function of change in individual outlet exposure, adjusting for confounding variables, and (2 spatial models of the change in counts/rates of each outcome measure and outlet density. We will assess the impact on health inequalities and will correct for population migration. Discussion This inter-disciplinary study requires expertise in epidemiology and public health, health informatics, medical statistics

  18. Stochastic Effects in Microstructure

    Directory of Open Access Journals (Sweden)

    Glicksman M.E.

    2002-01-01

    Full Text Available We are currently studying microstructural responses to diffusion-limited coarsening in two-phase materials. A mathematical solution to late-stage multiparticle diffusion in finite systems is formulated with account taken of particle-particle interactions and their microstructural correlations, or "locales". The transition from finite system behavior to that for an infinite microstructure is established analytically. Large-scale simulations of late-stage phase coarsening dynamics show increased fluctuations with increasing volume fraction, Vv, of the mean flux entering or leaving particles of a given size class. Fluctuations about the mean flux were found to depend on the scaled particle size, R/, where R is the radius of a particle and is the radius of the dispersoid averaged over the population within the microstructure. Specifically, small (shrinking particles tend to display weak fluctuations about their mean flux, whereas particles of average, or above average size, exhibit strong fluctuations. Remarkably, even in cases of microstructures with a relatively small volume fraction (Vv ~ 10-4, the particle size distribution is broader than that for the well-known Lifshitz-Slyozov limit predicted at zero volume fraction. The simulation results reported here provide some additional surprising insights into the effect of diffusion interactions and stochastic effects during evolution of a microstructure, as it approaches its thermodynamic end-state.

  19. Inhomogeneous microstructural growth by irradiation

    DEFF Research Database (Denmark)

    Krishan, K.; Singh, Bachu Narain; Leffers, Torben

    1985-01-01

    In the present paper we discuss the development of heterogeneous microstructure for uniform irradiation conditions. It is shown that microstructural inhomogeneities on a scale of 0.1 μm can develop purely from kinematic considerations because of the basic structure of the rate equations used...... to describe such evolution. Two aspects of the growth of such inhomogeneities are discussed. Firstly, it is shown that a local variation in the sink densities of the various microstructural defects will tend to enhance the inhomogeneity rather than remove it. Secondly, such inhomogeneities will lead to point...... defect fluxes that result in a spatial growth of the inhomogeneous region, which will be stopped only when the microstructural density around this region becomes large. The results have important implications in the formation of denuded zones and void formation in metals....

  20. Lymphatic Vessel Density as Prognostic Factor in Breast Carcinoma: Relation to Clinico pathologic Parameters

    International Nuclear Information System (INIS)

    El-Gendi, S.; Abdel-Hadi, M.

    2009-01-01

    Angiogenesis and lymphangiogenesis are essential for breast cancer growth and progression. This study aimed at investigating lymphatic micro vessel density (LVD) and microvessel density (MVD) as prognostic markers in breast carcinoma. Forty breast carcinomas were immuno stained for D2-40, CD31 and VEGF. Median lymphatic and blood micro vessel densities, as well as VEGF expression, were related to each other and to clinico pathologic parameters including lymph node (Ln) status. The efficacy of haematoxylin and eosin (H and E) in detecting lymphatic vessel invasion (LVI) compared to D2-40 immunostaining was also investigated. D2-40 stained normal lymphatic endothelium and myoepithelial cells, but with different staining patterns. D2-40 LVD related significantly to CD31 counts (r=0.470; p=0.002), and LN metastasis (Mann-Whitney U=101.500; p=0.043); however, it did not relate to age, tumor grade, tumor size or LVI. D2-40 identified LVI in 3 more cases (7.5%) than those detected by H and E. VEGF was expressed in 85% of cases, and was significantly related to CD31 and D2-40 counts (p=0.033 and 0.007, respectively). In conclusion, D2-40 LVD showed a significant association with LN metastasis, and can be considered to segregate patients with positive from those with negative LNs. D2-40 enhances the detection of LVI relative to H and E staining reflecting a potential for lymphatic metastatic spread and possible poor prognosis

  1. The relative importance of topography and RGD ligand density for endothelial cell adhesion.

    Directory of Open Access Journals (Sweden)

    Guillaume Le Saux

    Full Text Available The morphology and function of endothelial cells depends on the physical and chemical characteristics of the extracellular environment. Here, we designed silicon surfaces on which topographical features and surface densities of the integrin binding peptide arginine-glycine-aspartic acid (RGD could be independently controlled. We used these surfaces to investigate the relative importance of the surface chemistry of ligand presentation versus surface topography in endothelial cell adhesion. We compared cell adhesion, spreading and migration on surfaces with nano- to micro-scaled pyramids and average densities of 6×10(2-6×10(11 RGD/mm(2. We found that fewer cells adhered onto rough than flat surfaces and that the optimal average RGD density for cell adhesion was 6×10(5 RGD/mm(2 on flat surfaces and substrata with nano-scaled roughness. Only on surfaces with micro-scaled pyramids did the topography hinder cell migration and a lower average RGD density was optimal for adhesion. In contrast, cell spreading was greatest on surfaces with 6×10(8 RGD/mm(2 irrespectively of presence of feature and their size. In summary, our data suggest that the size of pyramids predominately control the number of endothelial cells that adhere to the substratum but the average RGD density governs the degree of cell spreading and length of focal adhesion within adherent cells. The data points towards a two-step model of cell adhesion: the initial contact of cells with a substratum may be guided by the topography while the engagement of cell surface receptors is predominately controlled by the surface chemistry.

  2. Measurement of average density and relative volumes in a dispersed two-phase fluid

    Science.gov (United States)

    Sreepada, Sastry R.; Rippel, Robert R.

    1992-01-01

    An apparatus and a method are disclosed for measuring the average density and relative volumes in an essentially transparent, dispersed two-phase fluid. A laser beam with a diameter no greater than 1% of the diameter of the bubbles, droplets, or particles of the dispersed phase is directed onto a diffraction grating. A single-order component of the diffracted beam is directed through the two-phase fluid and its refraction is measured. Preferably, the refracted beam exiting the fluid is incident upon a optical filter with linearly varing optical density and the intensity of the filtered beam is measured. The invention can be combined with other laser-based measurement systems, e.g., laser doppler anemometry.

  3. The Temperature-Density Relation in the Intergalactic Medium at Redshift langzrang = 2.4

    Science.gov (United States)

    Rudie, Gwen C.; Steidel, Charles C.; Pettini, Max

    2012-10-01

    We present new measurements of the temperature-density (T-ρ) relation for neutral hydrogen in the 2.0 law index of (Γ - 1) = 0.15 ± 0.02. Using analytic arguments, these measurements imply an "equation of state" for the IGM at langzrang = 2.4 of the form T=T_0 \\left(\\rho /\\bar{\\rho }\\right)^{\\gamma -1} with a temperature at mean density of T 0 = [1.94 ± 0.05] × 104 K and a power-law index (γ - 1) = 0.46 ± 0.05. Based on data obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration, and was made possible by the generous financial support of the W. M. Keck Foundation.

  4. Density and success of bird nests relative to grazing on western Montana grasslands

    Science.gov (United States)

    Fondell, Thomas F.; Ball, I.J.

    2004-01-01

    Grassland birds are declining at a faster rate than any other group of North American bird species. Livestock grazing is the primary economic use of grasslands in the western United States, but the effects of this use on distribution and productivity of grassland birds are unclear. We examined nest density and success of ground-nesting birds on grazed and ungrazed grasslands in western Montana. In comparison to grazed plots, ungrazed plots had reduced forb cover, increased litter cover, increased litter depth, and increased visual obstruction readings (VOR) of vegetation. Nest density among 10 of 11 common bird species was most strongly correlated with VOR of plots, and greatest nest density for each species occurred where mean VOR of the plot was similar to mean VOR at nests. Additionally, all bird species were relatively consistent in their choice of VOR at nests despite substantial differences in VOR among plots. We suggest that birds selected plots based in part on availability of suitable nest sites and that variation in nest density relative to grazing reflected the effect of grazing on availability of nest sites. Nest success was similar between grazed plots and ungrazed plots for two species but was lower for nests on grazed plots than on ungrazed plots for two other species because of increased rates of predation, trampling, or parasitism by brown-headed cowbirds (Molothrus ater). Other species nested almost exclusively on ungrazed plots (six species) or grazed plots (one species), precluding evaluation of the effects of grazing on nest success. We demonstrate that each species in a diverse suite of ground-nesting birds preferentially used certain habitats for nesting and that grazing altered availability of preferred nesting habitats through changes in vegetation structure and plant species composition. We also show that grazing directly or indirectly predisposed some bird species to increased nesting mortality. Management alternatives that avoid

  5. Dependences of microstructure and critical current density on the thickness of YBa2Cu3O7-x film prepared by pulsed laser deposition on buffered Ni–W tape

    International Nuclear Information System (INIS)

    Xu, Da; Wang, Ying; Liu, Linfei; Li, Yijie

    2013-01-01

    YBa 2 Cu 3 O 7−x (YBCO) films with different thicknesses were fabricated on buffered Ni–W tapes by pulsed laser deposition. The thickness dependences of microstructure and critical current density (J c ) of YBCO film were systematically investigated. The microstructure and surface morphology of YBCO film were characterized by X-ray diffraction, optical microscopy, field emission scanning electron microscopy and atomic force microscopy. And the critical current (I c ) of YBCO film was measured by the conventional four-probe method. We found that the full width at half maximum values of both omega and phi scan rocking curves, the content of a-axis oriented grain, and surface roughness of YBCO film all increased with augmenting the thickness of YBCO film. It was also found that with increasing the thickness of YBCO film from 0.3 μm to 1.5 μm, the I c of YBCO film increased from 72 A/cm to 248 A/cm and yet J c of YBCO film decreased from 2.1 × 10 6 A/cm 2 to 1.6 × 10 6 A/cm 2 . Our results indicated that the microstructure and J c of YBCO film were largely dependent on the thickness of YBCO film under the optimized deposition condition of substrate temperature. - Highlights: ► YBa 2 Cu 3 O 7−x (YBCO) films with different thicknesses were grown on metallic tapes. ► The texture and critical current were dependent on the thickness of YBCO film. ► Thickness effect was weakened by fabricating YBCO film layer by layer

  6. Brief report: The Brief Alcohol Social Density Assessment (BASDA): convergent, criterion-related, and incremental validity.

    Science.gov (United States)

    MacKillop, James; Acker, John D; Bollinger, Jared; Clifton, Allan; Miller, Joshua D; Campbell, W Keith; Goodie, Adam S

    2013-09-01

    Alcohol misuse is substantially influenced by social factors, but systematic assessments of social network drinking are typically lengthy. The goal of the present study was to provide further validation of a brief measure of social network alcohol use, the Brief Alcohol Social Density Assessment (BASDA), in a sample of emerging adults. Specifically, the study sought to examine the BASDA's convergent, criterion, and incremental validity in relation to well-established measures of drinking motives and problematic drinking. Participants were 354 undergraduates who were assessed using the BASDA, the Alcohol Use Disorders Identification Test (AUDIT), and the Drinking Motives Questionnaire. Significant associations were observed between the BASDA index of alcohol-related social density and alcohol misuse, social motives, and conformity motives, supporting convergent validity. Criterion-related validity was supported by evidence that significantly greater alcohol involvement was present in the social networks of individuals scoring at or above an AUDIT score of 8, a validated criterion for hazardous drinking. Finally, the BASDA index was significantly associated with alcohol misuse above and beyond drinking motives in relation to AUDIT scores, supporting incremental validity. Taken together, these findings provide further support for the BASDA as an efficient measure of drinking in an individual's social network. Methodological considerations as well as recommendations for future investigations in this area are discussed.

  7. Macular pigment density in relation to serum and adipose tissue concentrations of lutein and serum concentrations of zeaxanthin

    NARCIS (Netherlands)

    Broekmans, W.M.R.; Berendschot, T.T.J.R.; Klöpping-Ketelaars, I.A.A.; Vries, A.J. de; Goldbohm, R.A.; Tijburg, L.B.M.; Kardinaal, A.F.M.; Poppel, G. van

    2002-01-01

    Background: Macular pigment (MP), concentrated in the central area of the retina, contains the carotenoids lutein and zeaxanthin. A low MP density could be a risk factor for age-related macular degeneration. Little information is available regarding MP density in relation to serum lutein and

  8. Dispersion relations of density fluctuations observed by heavy ion beam probe in the TEXT tokamak

    International Nuclear Information System (INIS)

    Ross, D.W.

    1990-09-01

    Wave numbers as functions of frequency for density fluctuations in the core of the TEXT tokamak are measured in Heavy Ion Beam Probe experiments by analyzing the relative phases of signals originating from nearby points in the plasma. The adjacent points are typically 2 cm apart, with their relative orientation (δr, δθ) depending on position (r,θ). for angular frequencies ω ≤ 10 6 /s the signals are quite coherent, leading to reasonably well-defined ''dispersion relations.'' These do not correspond to known modes of the drift wave type, i.e., ballooning or slab-like electron drift waves or ion temperature gradient modes. The effect of finite sample volume size does not significantly alter this conclusion. 25 refs., 6 figs., 3 tabs

  9. Density Variations in Quartz As a Key for Deciphering Impact-Related Ultrasonic Sounding (Rajlich's Hypothesis)?

    Science.gov (United States)

    Mestan, J.; Alvarez Polanco, E. I.

    2014-12-01

    Ultrasound is a form of mechanical energy with a frequency greater than ≈ 20 kHz (upper human hearing limit). It is used in many scientific as well as industrial fields. Most modern applications of ultrasound utilize sources which are either piezoelectric or magnetostrictive (Benwell et Bly 1987). A meteorite impact has been considered to be an ultrasound source during last years (Rajlich 2011). Rajlich (2014) is coming with a hypothesis that white planes made of microcavities in Bohemian quartz have their origin in an impact-related ultrasonic sounding. The Bohemian Massif has been considered to be one of the largest impact craters in whole of the world (Papagiannis et El-Baz 1988, Papagiannis 1989, Rajlich 2014). Rajlich's hypothesis implies a liquid behavior of quartz during the impact event. We state that then there have to exist planes of slightly higher density than their surroundings together with planes of microcavities. They should intersect each other without mutual influencing (as in a case of planes made of microcavities). Because physics of ultrasound during an impact event is a brand new and unknown field, we try to choose a simple way of its cognition. It is possible to take the sine wave and set 3 requirements. (1) There exist some surroundings of points of peak amplitudes. (2) These surroundings are of higher density (compression) or lower density (rarefaction) than the mean density of quartz. (3) The difference between the higher/lower and surrounding density is measurable. There was done an experimental study of Bohemian quartz using QCT bone densitometry at the Radiology Munich. Quartz with a size of ≈ 5 x 8 cm absorbed too much RTG radiation (kV 140, mAs 330), which made a picture of internal structure impossible. We propose another techniques and appeal to other scientists to face this challenge. If Bohemian quartz has a harmonically distributed density, we consider it to be a support for Rajlich's hypothesis. AcknowledgementsWe would like

  10. Pain sensitivity is inversely related to regional grey matter density in the brain.

    Science.gov (United States)

    Emerson, Nichole M; Zeidan, Fadel; Lobanov, Oleg V; Hadsel, Morten S; Martucci, Katherine T; Quevedo, Alexandre S; Starr, Christopher J; Nahman-Averbuch, Hadas; Weissman-Fogel, Irit; Granovsky, Yelena; Yarnitsky, David; Coghill, Robert C

    2014-03-01

    Pain is a highly personal experience that varies substantially among individuals. In search of an anatomical correlate of pain sensitivity, we used voxel-based morphometry to investigate the relationship between grey matter density across the whole brain and interindividual differences in pain sensitivity in 116 healthy volunteers (62 women, 54 men). Structural magnetic resonance imaging (MRI) and psychophysical data from 10 previous functional MRI studies were used. Age, sex, unpleasantness ratings, scanner sequence, and sensory testing location were added to the model as covariates. Regression analysis of grey matter density across the whole brain and thermal pain intensity ratings at 49°C revealed a significant inverse relationship between pain sensitivity and grey matter density in bilateral regions of the posterior cingulate cortex, precuneus, intraparietal sulcus, and inferior parietal lobule. Unilateral regions of the left primary somatosensory cortex also exhibited this inverse relationship. No regions showed a positive relationship to pain sensitivity. These structural variations occurred in areas associated with the default mode network, attentional direction and shifting, as well as somatosensory processing. These findings underscore the potential importance of processes related to default mode thought and attention in shaping individual differences in pain sensitivity and indicate that pain sensitivity can potentially be predicted on the basis of brain structure. Copyright © 2013 International Association for the Study of Pain. Published by Elsevier B.V. All rights reserved.

  11. Application of ultra-small-angle X-ray scattering / X-ray photon correlation spectroscopy to relate equilibrium or non-equilibrium dynamics to microstructure

    Science.gov (United States)

    Allen, Andrew; Zhang, Fan; Levine, Lyle; Ilavsky, Jan

    2013-03-01

    Ultra-small-angle X-ray scattering (USAXS) can probe microstructures over the nanometer-to-micrometer scale range. Through use of a small instrument entrance slit, X-ray photon correlation spectroscopy (XPCS) exploits the partial coherence of an X-ray synchrotron undulator beam to provide unprecedented sensitivity to the dynamics of microstructural change. In USAXS/XPCS studies, the dynamics of local structures in a scale range of 100 nm to 1000 nm can be related to an overall hierarchical microstructure extending from 1 nm to more than 1000 nm. Using a point-detection scintillator mode, the equilibrium dynamics at ambient temperature of small particles (which move more slowly than nanoparticles) in aqueous suspension have been quantified directly for the first time. Using a USAXS-XPCS scanning mode for non-equilibrium dynamics incipient processes within dental composites have been elucidated, prior to effects becoming detectable using any other technique. Use of the Advanced Photon Source, an Office of Science User Facility operated for the United States Department of Energy (U.S. DOE) Office of Science by Argonne National Laboratory, was supported by the U.S. DOE under Contract No. DE-AC02-06CH11357.

  12. Effects of relative density and accumulated shear strain on post-liquefaction residual deformation

    Directory of Open Access Journals (Sweden)

    J. Kim

    2013-10-01

    Full Text Available The damage caused by liquefaction, which occurs following an earthquake, is usually because of settlement and lateral spreading. Generally, the evaluation of liquefaction has been centered on settlement, that is, residual volumetric strain. However, in actual soil, residual shear and residual volumetric deformations occur simultaneously after an earthquake. Therefore, the simultaneous evaluation of the two phenomena and the clarification of their relationship are likely to evaluate post-liquefaction soil behaviors more accurately. Hence, a quantitative evaluation of post-liquefaction damage will also be possible. In this study, the effects of relative density and accumulated shear strain on post-liquefaction residual deformations were reviewed through a series of lateral constrained-control hollow cylindrical torsion tests under undrained conditions. In order to identify the relationship between residual shear and residual volumetric strains, this study proposed a new test method that integrates monotonic loading after cyclic loading, and K0-drain after cyclic loading – in other words, the combination of cyclic loading, monotonic loading, and the K0 drain. In addition, a control that maintained the lateral constrained condition across all the processes of consolidation, cyclic loading, monotonic loading, and drainage was used to reproduce the anisotropy of in situ ground. This lateral constrain control was performed by controlling the axial strain, based on the assumption that under undrained conditions, axial and lateral strains occur simultaneously, and unless axial strain occurs, lateral strain does not occur. The test results confirmed that the recovery of effective stresses, which occur during monotonic loading and drainage after cyclic loading, respectively, result from mutually different structural restoration characteristics. In addition, in the ranges of 40–60% relative density and 50–100% accumulated shear strain, relative

  13. Nest site preference depends on the relative density of conspecifics and heterospecifics in wild birds.

    Science.gov (United States)

    Samplonius, Jelmer M; Kromhout Van Der Meer, Iris M; Both, Christiaan

    2017-01-01

    Social learning allows animals to eavesdrop on ecologically relevant knowledge of competitors in their environment. This is especially important when selecting a habitat if individuals have relatively little personal information on habitat quality. It is known that birds can use both conspecific and heterospecific information for social learning, but little is known about the relative importance of each information type. If provided with the choice between them, we expected that animals should copy the behaviour of conspecifics, as these confer the best information for that species. We tested this hypothesis in the field for Pied Flycatchers Ficedula hypoleuca arriving at their breeding grounds to select a nest box for breeding. We assigned arbitrary symbols to nest boxes of breeding pied flycatchers (conspecifics) and blue and great tits, Cyanistes caeruleus and Parus major (heterospecifics), in 2014 and 2016 in two areas with different densities of tits and flycatchers. After ca 50% of flycatchers had returned and a flycatcher symbol was assigned to their nest box, we gave the later arriving flycatchers the choice between empty nest boxes with either a conspecific (flycatcher) or a heterospecific (tit) symbol. As expected, Pied Flycatchers copied the perceived nest box choice of conspecifics, but only in areas that were dominated by flycatchers. Against our initial expectation, flycatchers copied the perceived choice of heterospecifics in the area heavily dominated by tits, even though conspecific minority information was present. Our results confirm that the relative density of conspecifics and heterospecifics modulates the propensity to copy or reject novel behavioural traits. By contrasting conspecific and heterospecific ecology in the same study design we were able to draw more general conclusions about the role of fluctuating densities on social information use.

  14. Magnetic resonance fiber density mapping of age-related white matter changes

    International Nuclear Information System (INIS)

    Stadlbauer, Andreas; Ganslandt, Oliver; Salomonowitz, Erich; Buchfelder, Michael; Hammen, Thilo; Bachmair, Johanna; Eberhardt, Knut

    2012-01-01

    Objectives: To introduce fiber density mapping (FDM) for investigation of age-related white matter (WM) changes and to compare its capabilities with conventional diffusion tensor imaging (DTI) post-processing. Methods: DTI data with 1.9 mm 3 isotropic voxels were acquired from 44 healthy volunteers (18–88 years) at 3 T. FDM is a 3-step approach which includes diagonalization of the diffusion tensor, fiber reconstruction for the whole brain, and calculation of fiber density (FD) values. Maps of fractional anisotropy (FA) and mean diffusivity (MD) were additionally calculated. Voxel-based analyses were performed to determine volume clusters of significant correlation with age. Bivariate linear regression models and Hotelling–Williams tests were used to detect significant differences between correlations. Results: FDM detected a larger WM volume affected by age-related changes concomitant with fewer significant clusters compared to FA and MD. This indicates that WM alterations due to normal aging occur rather globally than locally. FD values showed a significant stronger correlation with age in frontal lobes (prefrontal and precentral gyrus), limbic lobes (cingulate and parahippocampal gyrus), the corpus callosum (genu) and temporal lobes. Conclusions: FDM shows higher sensitivity for detection of age-related WM changes because it includes all surrounding fiber structures into the evaluation of each DTI data voxel.

  15. The relation between bone mineral density and lifestyle in college students

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Tae Hun; Lee, Mu Sik; Bae, Suk Hwan; KIm, Yong Kwon [Konyang University, Nonsan (Korea, Republic of)

    2016-09-15

    This study was performed in order to identify the relation between bone nineral density and life styles of some of Korean colleague students. A total of 121 college students were assessed through bone mineral density test on femoral neck and lumbar spine using dual energy X-ray absorptiometry(DEXA). The survey about their lifestyles with a self-rating questionnaire, was conducted from September 2014 to November 2014. SPSS 18.0 Program was used for those research data analyses such as the frequency analysis, the cross analysis. The percentage of the osteoporisis, osteopenia and normal groups were 0.0%, 24.8% and 75.2%. BMI, Regular menstrual cycle, Walking and Regular exercise in adolescence were positively related with T-score. But Using time of electronic devices was negative related with T-score. It can be concluded that desirable life style in time of college students and adolescence is important for their bone health. The necessity of preparing guideline for preventing bone disease in old age connected with the school curriculum should be recognized to the public and educational authorities.

  16. The relation between bone mineral density and lifestyle in college students

    International Nuclear Information System (INIS)

    Kang, Tae Hun; Lee, Mu Sik; Bae, Suk Hwan; KIm, Yong Kwon

    2016-01-01

    This study was performed in order to identify the relation between bone nineral density and life styles of some of Korean colleague students. A total of 121 college students were assessed through bone mineral density test on femoral neck and lumbar spine using dual energy X-ray absorptiometry(DEXA). The survey about their lifestyles with a self-rating questionnaire, was conducted from September 2014 to November 2014. SPSS 18.0 Program was used for those research data analyses such as the frequency analysis, the cross analysis. The percentage of the osteoporisis, osteopenia and normal groups were 0.0%, 24.8% and 75.2%. BMI, Regular menstrual cycle, Walking and Regular exercise in adolescence were positively related with T-score. But Using time of electronic devices was negative related with T-score. It can be concluded that desirable life style in time of college students and adolescence is important for their bone health. The necessity of preparing guideline for preventing bone disease in old age connected with the school curriculum should be recognized to the public and educational authorities

  17. Magnetic resonance fiber density mapping of age-related white matter changes

    Energy Technology Data Exchange (ETDEWEB)

    Stadlbauer, Andreas, E-mail: andi@nmr.at [MR Physics Group, Department of Radiology, Landesklinikum St. Poelten, Propst Fuehrer Strasse 4, A-3100 St. Poelten (Austria); Department of Neurosurgery, University of Erlangen-Nuremberg, Schwabachanlage 6, 91054 Erlangen (Germany); Ganslandt, Oliver [Department of Neurosurgery, University of Erlangen-Nuremberg, Schwabachanlage 6, 91054 Erlangen (Germany); Salomonowitz, Erich [MR Physics Group, Department of Radiology, Landesklinikum St. Poelten, Propst Fuehrer Strasse 4, A-3100 St. Poelten (Austria); Buchfelder, Michael [Department of Neurosurgery, University of Erlangen-Nuremberg, Schwabachanlage 6, 91054 Erlangen (Germany); Hammen, Thilo [Department of Neurology, Epilepsy Center, University of Erlangen-Nuremberg, Schwabachanlage 6, D-90429 Erlangen (Germany); Bachmair, Johanna [MR Physics Group, Department of Radiology, Landesklinikum St. Poelten, Propst Fuehrer Strasse 4, A-3100 St. Poelten (Austria); Eberhardt, Knut [Krankenhaus Schloss Werneck, MRT-Kompetenzzentrum, Balthasar-Neumann-Platz 1, D-97440 Werneck (Germany)

    2012-12-15

    Objectives: To introduce fiber density mapping (FDM) for investigation of age-related white matter (WM) changes and to compare its capabilities with conventional diffusion tensor imaging (DTI) post-processing. Methods: DTI data with 1.9 mm{sup 3} isotropic voxels were acquired from 44 healthy volunteers (18–88 years) at 3 T. FDM is a 3-step approach which includes diagonalization of the diffusion tensor, fiber reconstruction for the whole brain, and calculation of fiber density (FD) values. Maps of fractional anisotropy (FA) and mean diffusivity (MD) were additionally calculated. Voxel-based analyses were performed to determine volume clusters of significant correlation with age. Bivariate linear regression models and Hotelling–Williams tests were used to detect significant differences between correlations. Results: FDM detected a larger WM volume affected by age-related changes concomitant with fewer significant clusters compared to FA and MD. This indicates that WM alterations due to normal aging occur rather globally than locally. FD values showed a significant stronger correlation with age in frontal lobes (prefrontal and precentral gyrus), limbic lobes (cingulate and parahippocampal gyrus), the corpus callosum (genu) and temporal lobes. Conclusions: FDM shows higher sensitivity for detection of age-related WM changes because it includes all surrounding fiber structures into the evaluation of each DTI data voxel.

  18. Mechanical behavior and related microstructural aspects of a nano-lamellar TiAl alloy at elevated temperatures

    International Nuclear Information System (INIS)

    Klein, T.; Usategui, L.; Rashkova, B.; Nó, M.L.; San Juan, J.; Clemens, H.; Mayer, S.

    2017-01-01

    Advanced intermetallic γ-TiAl based alloys, which solidify via the disordered β phase, such as the TNM"+ alloy, are considered as most promising candidates for structural applications at high temperatures in aero and automotive industries, where they are applied increasingly. Particularly creep resistant microstructures required for high-temperature application, i.e. fine fully lamellar microstructures, can be attained via two-step heat-treatments. Thereby, an increasing creep resistance is observed with decreasing lamellar interface spacing. Once lamellar structures reach nano-scaled dimensions, deformation mechanisms are altered dramatically. Hence, this study deals with a detailed characterization of the elevated temperature deformation phenomena prevailing in nano-lamellar TiAl alloys by the use of tensile creep experiments and mechanical spectroscopy. Upon creep exposure, microstructural changes occur in the lamellar structure, which are analyzed by the comparative utilization of X-ray diffraction, scanning and transmission electron microscopy as well as atom probe tomography. Creep activation parameters determined by mechanical characterization suggest the dominance of dislocation climb by a jog-pair formation process. The dislocations involved in deformation are, in nano-lamellar TiAl alloys, situated at the lamellar interfaces. During creep exposure the precipitation of β_o phase and ζ-silicide particles is observed emanating from the α_2 phase, which is due to the accumulation of Mo and Si at lamellar interfaces.

  19. Topology of charge density of flucytosine and related molecules and characteristics of their bond charge distributions.

    Science.gov (United States)

    Murgich, Juan; Franco, Héctor J; San-Blas, Gioconda

    2006-08-24

    The molecular charge distribution of flucytosine (4-amino-5-fluoro-2-pyrimidone), uracil, 5-fluorouracil, and thymine was studied by means of density functional theory calculations (DFT). The resulting distributions were analyzed by means of the atoms in molecules (AIM) theory. Bonds were characterized through vectors formed with the charge density value, its Laplacian, and the bond ellipticity calculated at the bond critical point (BCP). Within each set of C=O, C-H, and N-H bonds, these vectors showed little dispersion. C-C bonds formed three different subsets, one with a significant degree of double bonding, a second corresponding to single bonds with a finite ellipticity produced by hyperconjugation, and a third one formed by a pure single bond. In N-C bonds, a decrease in bond length (an increase in double bond character) was not reflected as an increase in their ellipticity, as in all C-C bonds studied. It was also found that substitution influenced the N-C, C-O, and C-C bond ellipticity much more than density and its Laplacian at the BCP. The Laplacian of charge density pointed to the existence of both bonding and nonbonding maxima in the valence shell charge concentration of N, O, and F, while only bonding ones were found for the C atoms. The nonbonding maxima related to the sites for electrophilic attack and H bonding in O and N, while sites of nucleophilic attack were suggested by the holes in the valence shell of the C atoms of the carbonyl groups.

  20. GAMA/H-ATLAS: THE DUST OPACITY-STELLAR MASS SURFACE DENSITY RELATION FOR SPIRAL GALAXIES

    Energy Technology Data Exchange (ETDEWEB)

    Grootes, M. W.; Tuffs, R. J.; Andrae, E. [Max-Planck-Institut fuer Kernphysik, Saupfercheckweg 1, D-69117 Heidelberg (Germany); Popescu, C. C.; Pastrav, B. [Jeremiah Horrocks Institute, University of Central Lancashire, Preston PR1 2HE (United Kingdom); Gunawardhana, M.; Taylor, E. N. [Sydney Institute for Astronomy, School of Physics, University of Sydney, NSW 206 (Australia); Kelvin, L. S.; Driver, S. P. [Scottish Universities' Physics Alliance (SUPA), School of Physics and Astronomy, University of St. Andrews, North Haugh, St. Andrews KY16 9SS (United Kingdom); Liske, J. [European Southern Observatory, Karl-Schwarzschild Str. 2, D-85748 Garching (Germany); Seibert, M. [Observatories of the Carnegie Institution for Science, 813 Santa Barbara Street, Pasadena, CA 91101 (United States); Graham, Alister W. [Centre for Astrophysics and Supercomputing, Swinburne University of Technology, Hawthorn, Victoria 3122 (Australia); Baes, M. [Sterrenkundig Observatorium, Universiteit Gent, Krijgslaan 281 S9, B-9000 Gent (Belgium); Baldry, I. K. [Astrophysics Research Institute, Liverpool John Moores University, Twelve Quays House, Egerton Wharf, Birkenhead CH41 1LD (United Kingdom); Bourne, N. [Centre for Astronomy and Particle Theory, The School of Physics and Astronomy, Nottingham University, University Park Campus, Nottingham NG7 2RD (United Kingdom); Brough, S. [Australian Astronomical Observatory, P.O. Box 296, Epping, NSW 1710 (Australia); Cooray, A. [Department of Physics and Astronomy, University of California, Irvine, CA 92697 (United States); Dariush, A. [Physics Department, Imperial College, Prince Consort Road, London SW7 2AZ (United Kingdom); De Zotti, G. [INAF-Osservatorio Astronomico di Padova, Vicolo Osservatorio 5, I-35122 Padova (Italy); Dunne, L., E-mail: meiert.grootes@mpi-hd.mpg.de [Department of Physics and Astronomy, University of Canterbury, Private Bag 4800, Christchurch 8140 (New Zealand); and others

    2013-03-20

    We report the discovery of a well-defined correlation between B-band face-on central optical depth due to dust, {tau}{sup f}{sub B}, and the stellar mass surface density, {mu}{sub *}, of nearby (z {<=} 0.13) spiral galaxies. This relation was derived from a sample of spiral galaxies taken from the Galaxy and Mass Assembly (GAMA) survey, which were detected in the FIR/submillimeter (submm) in the Herschel-ATLAS science demonstration phase field. Using a quantitative analysis of the NUV attenuation-inclination relation for complete samples of GAMA spirals categorized according to stellar mass surface density, we demonstrate that this correlation can be used to statistically correct for dust attenuation purely on the basis of optical photometry and Sersic-profile morphological fits. Considered together with previously established empirical relationships of stellar mass to metallicity and gas mass, the near linearity and high constant of proportionality of the {tau}{sub B}{sup f} - {mu}{sub *} relation disfavors a stellar origin for the bulk of refractory grains in spiral galaxies, instead being consistent with the existence of a ubiquitous and very rapid mechanism for the growth of dust in the interstellar medium. We use the {tau}{sub B}{sup f} - {mu}{sub *} relation in conjunction with the radiation transfer model for spiral galaxies of Popescu and Tuffs to derive intrinsic scaling relations between specific star formation rate (SFR), stellar mass, and stellar surface density, in which attenuation of the UV light used for the measurement of SFR is corrected on an object-to-object basis. A marked reduction in scatter in these relations is achieved which we demonstrate is due to correction of both the inclination-dependent and face-on components of attenuation. Our results are consistent with a general picture of spiral galaxies in which most of the submm emission originates from grains residing in translucent structures, exposed to UV in the diffuse interstellar

  1. Bone Mineral Density, Mechanical, Microstructural Properties and Mineral Content of the Femur in Growing Rats Fed with Cactus Opuntia ficus indica (L.) Mill. (Cactaceae) Cladodes as Calcium Source in Diet.

    Science.gov (United States)

    Hernández-Becerra, Ezequiel; Gutiérrez-Cortez, Elsa; Del Real, Alicia; Rojas-Molina, Alejandra; Rodríguez-García, Mario; Rubio, Efraín; Quintero-García, Michelle; Rojas-Molina, Isela

    2017-02-04

    Mechanical, microstructural properties, mineral content and bone mineral density (BMD) of the femur were evaluated in growing rats fed with Opuntia ficus indica (L.) Mill. (Cactaceae) cladodes at different maturity stages as calcium source. Male weanling rats were fed with cladodes at early maturity stage (25 and 60 days of age, belonging to groups N-60 and N-200, respectively) and cladodes at late maturity stage (100 and 135 days of age, belonging to groups N-400 and N-600, respectively) for 6 weeks. Additionally, a control group fed with calcium carbonate as calcium source was included for comparative purposes. All diets were fitted to the same calcium content (5 g/kg diet). The failure load of femurs was significantly lower ( p ≤ 0.05) in groups N-60 and N-200 in comparison to N-400, N-600 and control groups. The cortical width (Ct.Wi) and trabecular thickness (Tb.Th) of the femurs in control and N-600 groups were significantly higher ( p ≤ 0.05) than Ct.Wi and Tb.Th of femurs in groups N-60 and N-200. Trabecular separation of the femurs in N-60 and N-200 groups showed the highest values compared with all experimental groups. The highest calcium content in the femurs were observed in control, N-600 and N-400 groups; whereas the lowest phosphorus content in the bones were detected in N-200, N-600 and N-400 groups. Finally, the BMD in all experimental groups increased with age; nevertheless, the highest values were observed in N-600 and control groups during pubertal and adolescence stages. The results derived from this research demonstrate, for the first time, that the calcium found in Opuntia ficus indica cladodes is actually bioavailable and capable of improving mineral density and mechanical and microstructural properties of the bones. These findings suggest that the consumption of cladodes at late maturity stage within the diet might have a beneficial impact on bone health.

  2. Low bone mineral density is related to atherosclerosis in postmenopausal Moroccan women

    Directory of Open Access Journals (Sweden)

    Cherkaoui Mohammed

    2009-10-01

    Full Text Available Abstract Background Some studies have implicated several possible metabolic linkages between osteoporosis and vascular calcification, including estrogen deficiency, vitamin D excess, vitamin K deficiency and lipid oxidation products. Nevertheless, it remains unclear whether osteoporosis and atherosclerosis are related to each other or are independent processes, both related to aging. The aim of this cross-sectional study was to evaluate the correlation between arterial thickening and bone status in a sample of apparently healthy Moroccan women. Methods Seventy-two postmenopausal women were studied. All patients were without secondary causes that might affect bone density. Bone status was assessed by bone mineral density (BMD in lumbar spine and all femoral sites. Arterial wall thickening was assessed by intima-media thickness (IMT in carotid artery (CA and femoral artery (FA. Prevalent plaques were categorized into four groups ranging from low echogenicity to high echogenicity. Results The mean age was 59.2 ± 8.3 years. 84.7% had at least one plaque. By Spearman Rank correlation, CA IMT was negatively correlated to Femoral total BMD (r = -0.33, Femoral neck BMD (r = -0.23, Ward triangle BMD (r = -0.30 and Trochanter BMD (r = -0.28 while there was no association with lumbar BMD. In multiple regression analysis, CA IMT emerged as an independent factor significantly associated with all femoral sites BMD after adjusting of confounding factors. FA IMT failed to be significantly associated with both Femoral and Lumbar BMD. No significant differences between echogenic, predominantly echogenic, predominantly echolucent and echolucent plaques groups were found concerning lumbar BMD and all femoral sites BMD Conclusion Our results demonstrate a negative correlation between bone mineral density (BMD qnd carotid intima-media thickness (IMT in postmenopausal women, independently of confounding factors. We suggest that bone status should be evaluated in

  3. Deformation microstructures

    DEFF Research Database (Denmark)

    Hansen, N.; Huang, X.; Hughes, D.A.

    2004-01-01

    Microstructural characterization and modeling has shown that a variety of metals deformed by different thermomechanical processes follows a general path of grain subdivision, by dislocation boundaries and high angle boundaries. This subdivision has been observed to very small structural scales...... of the order of 10 nm, produced by deformation under large sliding loads. Limits to the evolution of microstructural parameters during monotonic loading have been investigated based on a characterization by transmission electron microscopy. Such limits have been observed at an equivalent strain of about 10...

  4. The significance of relative density for particle damage in loaded and sheared gravels

    Directory of Open Access Journals (Sweden)

    Fityus Stephen

    2017-01-01

    Full Text Available For granular assemblages of strong particles, an increase in the relative density usually leads to a significant increase in shear strength, which is evident as a peak strength, accompanied by significant dilation as the peak strength is attained. This paper describes an experimental study of shearing in assemblages of weak particles, where particle breakage offsets dilation for all but the lowest of confining stresses. In such materials, prone to particle breakage, the shear strengths of loose and dense assemblages rapidly converge to similar values as confining stress increases, and any benefit of greater relative density is lost. This is attributed to the densification effect associated with the loading under a high stress prior to shearing, which is characterised by widespread particle breakage and the formation of smaller particles to occupy space between coarser ones. Interestingly, under both low and high stresses, there was a tendency for greater particle breakage in the loose samples, as a result of both shearing and compression. This result suggests that, despite the denser assemblage having its particles more rigidly constrained and less able to rearrange to avoid direct loading, the influence of greater load-spreading capacity afforded by an increased number of particle contacts in a denser sample, is more dominant in controlling breakage.

  5. Some features of excited states density matrix calculation and their pairing relations in conjugated systems

    International Nuclear Information System (INIS)

    Giambiagi, M.S. de; Giambiagi, M.

    1982-01-01

    Direct PPP-type calculations of self-consistent (SC) density matrices for excited states are described and the corresponding 'thawn' molecular orbitals (MO) are discussed. Special attention is addressed to particular solutions arising in conjugated systems of a certain symmetry, and to their chemical implications. The U(2) and U(3) algebras are applied respectively to the 4-electron and 6-electron cases: a natural separation of excited states in different cases follows. A simple approach to the convergence problem for excited states is given. The complementarity relations, an alternative formulation of the pairing theorem valid for heteromolecules and non-alternant systems, allow some fruitful experimental applications. Together with the extended pairing relations shown here, they may help to rationalize general trends. (Author) [pt

  6. Microstructure and mechanical properties of selective laser melted magnesium

    International Nuclear Information System (INIS)

    Ng, C.C.; Savalani, M.M.; Lau, M.L.; Man, H.C.

    2011-01-01

    The effects of laser processing parameters on the microstructure and mechanical properties of selective laser-melted magnesium were investigated. The results show that the microstructure characteristics of the laser-melted samples are dependent on the grain size of SLM magnesium. The grains in the molten zone coarsen as the laser energy density increases. In addition, the average hardness values of the molten zone decreases significantly with an increase of the laser energy densities and then decreased slowly at a relatively high laser energy density irrespective of mode of irradiation. The hardness value was obtained from 0.59 to 0.95 GPa and corresponding elastic modulus ranging from 27 to 33 GPa. The present selective laser-melted magnesium parts are promising for biomedical applications since the mechanical properties are more closely matched with human bone than other metallic biomaterials.

  7. Longitudinal Associations Between Microstructural Changes and Microperimetry in the Early Stages of Age-Related Macular Degeneration.

    Science.gov (United States)

    Wu, Zhichao; Cunefare, David; Chiu, Elizabeth; Luu, Chi D; Ayton, Lauren N; Toth, Cynthia A; Farsiu, Sina; Guymer, Robyn H

    2016-07-01

    To determine whether longitudinal changes in mesopic visual function on microperimetry occurred independent of its associations with microstructural parameters on spectral-domain optical coherence tomography (SD-OCT) in the early stages of AMD. Forty-one AMD eyes underwent microperimetry testing and SD-OCT scans over a 12-month period at 6-month intervals. Microstructural parameters analyzed include the retinal pigment epithelium-drusen complex (RPEDC) layer thickness, number of hyperreflective foci (HF) and their inner retinal migration (represented by a weighted axial distribution score; AxD), and the number of atrophic areas. Microperimetric sensitivity was 0.29 dB (95% confidence interval [CI] = -0.38 to -0.20 dB, P < 0.001) and 0.13 dB (95% CI = -0.22 to -0.03 dB, P = 0.008) lower in each sector for every 10-μm higher RPEDC layer thickness and 1-HF present, but was not associated with the AxD score or the number of atrophic areas present (P ≤ 0.464). However, each 10-μm greater RPEDC layer thickness and 1-HF present was not independently associated with a further decline in sensitivity (-0.08 dB/year, 95% CI = -0.24 to 0.07 dB/year, P = 0.288 and 0.09 dB/year, 95% CI = -0.06 to 0.24 dB/year, P = 0.242, respectively) over time when accounting for the association between RPEDC layer thickness and number of HF with microperimetric sensitivity. Longitudinal changes in mesopic visual function measured on microperimetry paralleled changes in the microstructural changes over a 12-month time frame, without any changes occurring independent of the associations between structure and function alone.

  8. Genetic predisposition for adult lactose intolerance and relation to diet, bone density, and bone fractures.

    Science.gov (United States)

    Obermayer-Pietsch, Barbara M; Bonelli, Christine M; Walter, Daniela E; Kuhn, Regina J; Fahrleitner-Pammer, Astrid; Berghold, Andrea; Goessler, Walter; Stepan, Vinzenz; Dobnig, Harald; Leb, Georg; Renner, Wilfried

    2004-01-01

    Evidence that genetic disposition for adult lactose intolerance significantly affects calcium intake, bone density, and fractures in postmenopausal women is presented. PCR-based genotyping of lactase gene polymorphisms may complement diagnostic procedures to identify persons at risk for both lactose malabsorption and osteoporosis. Lactase deficiency is a common autosomal recessive condition resulting in decreased intestinal lactose degradation. A -13910 T/C dimorphism (LCT) near the lactase phlorizin hydrolase gene, reported to be strongly associated with adult lactase nonpersistence, may have an impact on calcium supply, bone density, and osteoporotic fractures in the elderly. We determined LCT genotypes TT, TC, and CC in 258 postmenopausal women using a polymerase chain reaction-based assay. Genotypes were related to milk intolerance, nutritional calcium intake, intestinal calcium absorption, bone mineral density (BMD), and nonvertebral fractures. Twenty-four percent of all women were found to have CC genotypes and genetic lactase deficiency. Age-adjusted BMD at the hip in CC genotypes and at the spine in CC and TC genotypes was reduced by -7% to -11% depending on the site measured (p = 0.04). LCT(T/C-13910) polymorphisms alone accounted for 2-4% of BMD in a multiple regression model. Bone fracture incidence was significantly associated with CC genotypes (p = 0.001). Milk calcium intake was significantly lower (-55%, p = 0.004) and aversion to milk consumption was significantly higher (+166%, p = 0.01) in women with the CC genotype, but there were no differences in overall dietary calcium intake or in intestinal calcium absorption test values. The LCT(T/C-13910) polymorphism is associated with subjective milk intolerance, reduced milk calcium intake, and reduced BMD at the hip and the lumbar spine and may predispose to bone fractures. Genetic testing for lactase deficiency may complement indirect methods in the detection of individuals at risk for both lactose

  9. Microstructural evolution of cold-sprayed Inconel 625 superalloy coatings on low alloy steel substrate

    International Nuclear Information System (INIS)

    Chaudhuri, Atanu; Raghupathy, Y.; Srinivasan, Dheepa; Suwas, Satyam; Srivastava, Chandan

    2017-01-01

    This study illustrates microstructural evolution of INCONEL 625 superalloy coatings cold-sprayed on a 4130 chrome alloy steel with medium carbon content. INCONEL 625 powder (5–25 μm) were successfully cold sprayed without any oxidation. The comprehensive microstructure analysis of the as-sprayed coatings and of the substrate-coating interface was carried out using EBSD, TEM, and XRD. The coating microstructure at the substrate-coating interface was markedly different from the microstructure away from the interface. The coating microstructure at steel-coating interface consisted of a fine layer of small grains. The microstructure beyond this fine layer can be divided into splats, inter splat and intra splat boundaries. Both splat and splat boundaries exhibited deformation induced dislocations. Dynamic recovery of dislocations-ridden regions inside the splat was responsible for the development of sub grain structure inside a splat with both low and high angle grain boundaries. Splat-splat (inter splat) boundary consisted of a relatively high density of dislocations and shear bands as a result of adiabatic shear flow localisation. This flow instability is believed to enhance the microstructural integrity by eliminating porosity at splat-splat boundaries. Based on the microstructural analysis using electron microscopy, a plausible mechanism for the development of microstructure has been proposed in this work. Cold spray technique can thus be deployed to develop high quality coatings of commercial importance. - Graphical abstract: Schematics of the evolution of microstructure at the 4130 steel substrate close to interface. i) initial deformation close to interface. ii) Accumulation of dislocation in the substrate. iii) Formation of cell structure due to dislocation tangling and arrangement. iv) Dislocation rearrangement and subgrain formation. v.a) Formation HAGB from dislocation accumulation into LAGB. v.b) HAGB formation through DRX by progressive lattice rotation

  10. Substorm-related thermospheric density and wind disturbances derived from CHAMP observations

    Directory of Open Access Journals (Sweden)

    P. Ritter

    2010-06-01

    Full Text Available The input of energy and momentum from the magnetosphere is most efficiently coupled into the high latitude ionosphere-thermosphere. The phenomenon we are focusing on here is the magnetospheric substorm. This paper presents substorm related observations of the thermosphere derived from the CHAMP satellite. With its sensitive accelerometer the satellite can measure the air density and zonal winds. Based on a large number of substorm events the average high and low latitude thermospheric response to substorm onsets was deduced. During magnetic substorms the thermospheric density is enhanced first at high latitudes. Then the disturbance travels at an average speed of 650 m/s to lower latitudes, and 3–4 h later the bulge reaches the equator on the night side. Under the influence of the Coriolis force the travelling atmospheric disturbance (TAD is deflected westward. In accordance with present-day atmospheric models the disturbance zonal wind velocities during substorms are close to zero near the equator before midnight and attain moderate westward velocities after midnight. In general, the wind system is only weakly perturbed (Δvy<20 m/s by substorms.

  11. Method using a density field for locating related items for data mining

    Science.gov (United States)

    Wylie, Brian N.

    2002-01-01

    A method for locating related items in a geometric space transforms relationships among items to geometric locations. The method locates items in the geometric space so that the distance between items corresponds to the degree of relatedness. The method facilitates communication of the structure of the relationships among the items. The method makes use of numeric values as a measure of similarity between each pairing of items. The items are given initial coordinates in the space. An energy is then determined for each item from the item's distance and similarity to other items, and from the density of items assigned coordinates near the item. The distance and similarity component can act to draw items with high similarities close together, while the density component can act to force all items apart. If a terminal condition is not yet reached, then new coordinates can be determined for one or more items, and the energy determination repeated. The iteration can terminate, for example, when the total energy reaches a threshold, when each item's energy is below a threshold, after a certain amount of time or iterations.

  12. Effect of direct current density on microstructure of tungsten coating electroplated from Na{sub 2}WO{sub 4}-WO{sub 3}-NaPO{sub 3} system

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Fan, E-mail: jiangfan1109@163.com; Zhang, Yingchun, E-mail: zycustb@163.com; Sun, Ningbo, E-mail: suningbo682@163.com; Liu, Zhi’ang, E-mail: zhiang_001@163.com

    2014-10-30

    Highlights: • Tungsten coatings were electroplated from the Na{sub 2}WO{sub 4}-WO{sub 3}-NaPO{sub 3} melt. • Tungsten coating comprised a tooth-like layer and a columnar growth layer. • The average grain size increases as increasing current density. • (2 1 1) Orientation is favored most likely for samples obtained at various durations. • The growth rate of tungsten crystal nucleus is higher than the nucleation rate. - Abstract: Pure tungsten coating with body-centered cubic (bbc) structure was successfully electrodeposited from Na{sub 2}WO{sub 4}-WO{sub 3}-NaPO{sub 3} molten salt at 1153 K in atmosphere. The coatings comprised an inner layer of tooth-like grains and an outer layer of columnar grains with a thin diffusion layer of tungsten in the Cu substrate. The effects of current density and electrodeposition duration on the morphology and microstructure of the coatings were investigated in this paper. With increasing of current density from 50 to 80 mA cm{sup −2}, the grain size of the tungsten coating increased from 7.01 μm to 12.44 μm. With the increase of the current density, the thickness of the coating changed from 25.92 μm to 34.40 μm, and then dropped to 29.72 μm. The preferred orientation of the coatings changed from (2 2 0) to (2 1 1). With the increasing of duration, the grain size and thickness of tungsten coatings increased while the (2 1 1) favored orientation dot not changed. Because of the low current efficiency at long duration of direct current electrodeposition, it should not be suitable for the electroplating of thick tungsten coating.

  13. SEM Characterization of the High Burn-up Microstructure of U-7Mo Alloy

    Energy Technology Data Exchange (ETDEWEB)

    Dennis D. Keiser, Jr.; Jan-Fong Jue; Jian Gan; Brandon Miller; Adam Robinson; Pavel Medvedev; James Madden; Dan Wachs; M. Teague

    2014-04-01

    During irradiation, the microstructure of U-7Mo evolves until at a fission density near 5x1021 f/cm3 a high-burnup microstructure exists that is very different than what was observed at lower fission densities. This microstructure is dominated by randomly distributed, relatively large, homogeneous fission gas bubbles. The bubble superlattice has collapsed in many microstructural regions, and the fuel grain sizes, in many areas, become sub-micron in diameter with both amorphous fuel and crystalline fuel present. Solid fission product precipitates can be found inside the fission gas bubbles. To generate more information about the characteristics of the high-fission density microstructure, three samples irradiated in the RERTR-7 experiment have been characterized using a scanning electron microscope equipped with a focused ion beam. The FIB was used to generate samples for SEM imaging and to perform 3D reconstruction of the microstructure, which can be used to look for evidence of possible fission gas bubble interlinkage.

  14. Microstructures (clumps) in turbulent plasmas

    International Nuclear Information System (INIS)

    Balescu, R.; Misguich, J.H.

    1977-01-01

    A general analysis of binary correlations in a turbulent plasma leads to a functional relation relating correlations to the one-particle distribution function. Such a relation allows to understand the mechanism of generation of the microstructures or clumps introduced by Dupree. The expressions introduced by this author appear as a lowest approximation of the general equation. The features and interpretation of these microstructures are briefly discussed [fr

  15. Two-colour QCD at finite fundamental quark-number density and related theories

    International Nuclear Information System (INIS)

    Hands, S.J.; Kogut, J.B.; Morrison, S.E.; Sinclair, D.K.

    2001-01-01

    We are simulating SU(2) Yang-Mills theory with four flavours of dynamical quarks in the fundamental representation of SU(2) 'colour' at finite chemical potential, μ for quark number, as a model for QCD at finite baryon number density. In particular we observe that for μ large enough this theory undergoes a phase transition to a state with a diquark condensate which breaks quark-number symmetry. In this phase we examine the spectrum of light scalar and pseudoscalar bosons and see evidence for the Goldstone boson associated with this spontaneous symmetry breaking. This theory is closely related to QCD at finite chemical potential for isospin, a theory which we are now studying for SU(3) colour

  16. Two-colour QCD at finite fundamental quark-number density and related theories

    International Nuclear Information System (INIS)

    Hands, S. J.; Kogut, J. B.; Morrison, S. E.; Sinclair, D. K.

    2000-01-01

    We are simulating SU(2) Yang-Mills theory with four flavours of dynamical quarks in the fundamental representation of SU(2) colour at finite chemical potential, p for quark number, as a model for QCD at finite baryon number density. In particular we observe that for p large enough this theory undergoes a phase transition to a state with a diquark condensate which breaks quark-number symmetry. In this phase we examine the spectrum of light scalar and pseudoscalar bosons and see evidence for the Goldstone boson associated with this spontaneous symmetry breaking. This theory is closely related to QCD at finite chemical potential for isospin, a theory which we are now studying for SU(3) colour

  17. Microstructural evaluation of stressed IN625 and NiCrA1Y coated IN625 tested in high and low density SCW

    Energy Technology Data Exchange (ETDEWEB)

    Selvig, A.; Huang, X., E-mail: aselvig@connect.carleton.ca [Carleton Univ., Ottawa, Ontario (Canada); Guzonas, D. [Atomic Energy of Canada Limited, Chalk River, Ontario (Canada)

    2012-07-01

    The goal of this study was to determine the corrosion resistance of NiCrA1Y coatings for use in future supercritical water reactors (SCWR). The NiCrA1Y coating was applied to IN625 and was tested against bare IN625, under stress, in high density supercritical water (HDSCW) and low density supercritical water (LDSCW). The IN625 samples experienced intergranular corrosion in HDSCW but not in LDSCW as well as oxidation; whereas the NiCrA1Y sample experienced oxidation, with no other forms of corrosion observed. Thus, it is likely that NiCrA1Y coatings are more corrosion resistant than IN625 in HDSCW. (author)

  18. Antiosteoporosis Effect of Radix Scutellariae Extract on Density and Microstructure of Long Bones in Tail-Suspended Sprague-Dawley Rats

    Directory of Open Access Journals (Sweden)

    Chen-Rui Li

    2013-01-01

    Full Text Available Radix Scutellariae (RS, a medicinal herb, is extensively employed in traditional Chinese medicines and modern herbal prescriptions. Two major flavonoids in RS were known to induce osteoblastic differentiation and inhibit osteoclast differentiation, respectively. This study aimed to investigate the effect of Radix Scutellariae extract (RSE against bone loss induced by mechanical inactivity or weightlessness. A hindlimb unloading tail-suspended rat model (TS was established to determine the effect of RSE on bone mineral density and bone microarchitecture. Treatment of RSE at 50 mg/kg/day and alendronate (ALE at 2 mg/kg/day as positive control for 42 days significantly increased the bone mineral density and mechanical strength compared with TS group. Enhanced bone turnover markers by TS treatment were attenuated by RSE and ALE administration. Deterioration of bone trabecula induced by TS was prevented. Moreover, both treatments counteracted the reduction of bone volume fraction, trabecular thickness and number, and connectivity density. In conclusion, RSE was demonstrated for the first time to prevent osteoporosis induced by TS treatment, which suggests the potential application of RSE in the treatment of disuse-induced osteoporosis.

  19. Correlation of radiation-induced changes in microstructure/microchemistry, density and thermo-electric power of type 304L and 316 stainless steels irradiated in the Phénix reactor

    Energy Technology Data Exchange (ETDEWEB)

    Renault Laborne, Alexandra, E-mail: alexandra.renault@cea.fr [CEA, DEN, SRMA, F-91191 Gif-sur-Yvette (France); Gavoille, Pierre [CEA, DEN, SEMI, F-91191 Gif-sur-Yvette (France); Malaplate, Joël [CEA, DEN, SRMA, F-91191 Gif-sur-Yvette (France); Pokor, Cédric [EDF R& D, MMC, Site des Renardières, F-77818 Morêt-sur-Loing cedex (France); Tanguy, Benoît [CEA, DEN, SEMI, F-91191 Gif-sur-Yvette (France)

    2015-05-15

    Annealed specimens of type 304L and 316 stainless steel and cold-worked 316 specimens were irradiated in the Phénix reactor in the temperature range 381–394 °C and to different damage doses up to 39 dpa. The microstructure and microchemistry of both 304L and 316 have been examined using the combination of the different techniques of TEM to establish the void swelling and precipitation behavior under neutron irradiation. TEM observations are compared with results of measurements of immersion density and thermo-electric power obtained on the same irradiated stainless steels. The similarities and differences in their behavior on different scales are used to understand the factors in terms of the chemical composition and metallurgical state of steels, affecting the precipitation under irradiation and the swelling behavior. Irradiation induces the formation of some precipitate phases (e.g., M{sub 6}C and M{sub 23}C{sub 6}-type carbides, and γ’- and G-phases), Frank loops and cavities. According to the metallurgical state and chemical composition of the steel, the amount of each type of radiation-induced defects is not the same, affecting their density and thermo-electric power.

  20. Correlation of radiation-induced changes in microstructure/microchemistry, density and thermo-electric power of type 304L and 316 stainless steels irradiated in the Phénix reactor

    Science.gov (United States)

    Renault Laborne, Alexandra; Gavoille, Pierre; Malaplate, Joël; Pokor, Cédric; Tanguy, Benoît

    2015-05-01

    Annealed specimens of type 304L and 316 stainless steel and cold-worked 316 specimens were irradiated in the Phénix reactor in the temperature range 381-394 °C and to different damage doses up to 39 dpa. The microstructure and microchemistry of both 304L and 316 have been examined using the combination of the different techniques of TEM to establish the void swelling and precipitation behavior under neutron irradiation. TEM observations are compared with results of measurements of immersion density and thermo-electric power obtained on the same irradiated stainless steels. The similarities and differences in their behavior on different scales are used to understand the factors in terms of the chemical composition and metallurgical state of steels, affecting the precipitation under irradiation and the swelling behavior. Irradiation induces the formation of some precipitate phases (e.g., M6C and M23C6-type carbides, and γ'- and G-phases), Frank loops and cavities. According to the metallurgical state and chemical composition of the steel, the amount of each type of radiation-induced defects is not the same, affecting their density and thermo-electric power.

  1. Correlation of radiation-induced changes in microstructure/microchemistry, density and thermo-electric power of type 304L and 316 stainless steels irradiated in the Phénix reactor

    International Nuclear Information System (INIS)

    Renault Laborne, Alexandra; Gavoille, Pierre; Malaplate, Joël; Pokor, Cédric; Tanguy, Benoît

    2015-01-01

    Annealed specimens of type 304L and 316 stainless steel and cold-worked 316 specimens were irradiated in the Phénix reactor in the temperature range 381–394 °C and to different damage doses up to 39 dpa. The microstructure and microchemistry of both 304L and 316 have been examined using the combination of the different techniques of TEM to establish the void swelling and precipitation behavior under neutron irradiation. TEM observations are compared with results of measurements of immersion density and thermo-electric power obtained on the same irradiated stainless steels. The similarities and differences in their behavior on different scales are used to understand the factors in terms of the chemical composition and metallurgical state of steels, affecting the precipitation under irradiation and the swelling behavior. Irradiation induces the formation of some precipitate phases (e.g., M 6 C and M 23 C 6 -type carbides, and γ’- and G-phases), Frank loops and cavities. According to the metallurgical state and chemical composition of the steel, the amount of each type of radiation-induced defects is not the same, affecting their density and thermo-electric power

  2. Observer variability of absolute and relative thrombus density measurements in patients with acute ischemic stroke

    NARCIS (Netherlands)

    Santos, Emilie M. M.; Yoo, Albert J.; Beenen, Ludo F.; Berkhemer, Olvert A.; den Blanken, Mark D.; Wismans, Carrie; Niessen, Wiro J.; Majoie, Charles B.; Marquering, Henk A.; Fransen, Puck S. S.; Beumer, Debbie; van den Berg, Lucie A.; Lingsma, Hester F.; Schonewille, Wouter J.; Vos, Jan Albert; Nederkoorn, Paul J.; Wermer, Marieke J. H.; van Walderveen, Marianne A. A.; Staals, Julie; Hofmeijer, Jeannette; van Oostayen, Jacques A.; Lycklama à Nijeholt, Geert J.; Boiten, Jelis; Brouwer, Patrick A.; Emmer, Bart J.; de Bruijn, Sebastiaan F.; van Dijk, Lukas C.; Kappelle, L. Jaap; Lo, Rob H.; van Dijk, Ewoud J.; de Vries, Joost; de Kort, Paul L. M.; van den Berg, Jan S. P.; A A M van Hasselt, Boudewijn; Aerden, Leo A. M.; Dallinga, René J.; Visser, Marieke C.; Bot, Joseph C. J.; Vroomen, Patrick C.; Eshghi, Omid; Schreuder, Tobien H. C. M. L.; Heijboer, Roel J. J.; Keizer, Koos; Tielbeek, Alexander V.; Hertog, Heleen M. Den; Gerrits, Dick G.; van den Berg-Vos, Renske M.; Karas, Giorgos B.; Steyerberg, Ewout W.; Flach, H. Zwenneke; Sprengers, Marieke E. S.; Jenniskens, Sjoerd F. M.; van den Berg, René; Koudstaal, Peter J.; van Zwam, Wim H.; Roos, Yvo B. W. E. M.; van der Lugt, Aad; van Oostenbrugge, Robert J.; Dippel, Diederik W. J.

    2016-01-01

    Thrombus density may be a predictor for acute ischemic stroke treatment success. However, only limited data on observer variability for thrombus density measurements exist. This study assesses the variability and bias of four common thrombus density measurement methods by expert and non-expert

  3. Observer variability of absolute and relative thrombus density measurements in patients with acute ischemic stroke

    NARCIS (Netherlands)

    E.M.M. Santos (Emilie M.); A.J. Yoo (Albert J.); L.F.M. Beenen (Ludo); O.A. Berkhemer (Olvert); M.D. Den Blanken (Mark D.); C. Wismans (Carrie); W.J. Niessen (Wiro); C.B. Majoie (Charles); H. Marquering (Henk)

    2016-01-01

    textabstractIntroduction: Thrombus density may be a predictor for acute ischemic stroke treatment success. However, only limited data on observer variability for thrombus density measurements exist. This study assesses the variability and bias of four common thrombus density measurement methods by

  4. Observer variability of absolute and relative thrombus density measurements in patients with acute ischemic stroke

    NARCIS (Netherlands)

    Santos, E.M.; Yoo, A.J.; Beenen, L.F.; Berkhemer, O.A.; Blanken, M.D. den; Wismans, C.; Niessen, W.J.; Majoie, C.B.; Marquering, H.A.; Dijk, E.J. van; et al.,

    2016-01-01

    INTRODUCTION: Thrombus density may be a predictor for acute ischemic stroke treatment success. However, only limited data on observer variability for thrombus density measurements exist. This study assesses the variability and bias of four common thrombus density measurement methods by expert and

  5. Relative Influence of Prior Life Stages and Habitat Variables on Dragonfly (Odonata: Gomphidae Densities among Lake Sites

    Directory of Open Access Journals (Sweden)

    Alysa Remsburg

    2011-04-01

    Full Text Available Many aquatic species have discrete life stages, making it important to understand relative influences of the different habitats occupied within those populations. Although population demographics in one stage can carry over to spatially separated life stages, most studies of habitat associations have been restricted to a single life stage. Among Gomphidae dragonflies (Odonata: Anisoptera, recruitment via adult oviposition establishes initial population sizes of the aquatic larvae. However, spatial variability in larval survivorship could obscure the relationship between adult and larval densities. This study uses surveys conducted during 2005 and 2006 of Gomphidae larval, emergence, and adult stages from 22 lake sites in northern Wisconsin, USA, to investigate (1 whether the Gomphidae density of each life stage correlated spatially with that of the preceding life stage and (2 what habitat factors help explain variation in densities at each life stage. Results indicated that adult densities from the previous season helped predict densities of early-instar larvae. This finding suggests that oviposition site selection controlled the local larval distribution more than larval survivorship or movement. Late-instar larval densities helped predict densities of emerging Gomphidae later the same season, suggesting that variation in survivorship of final-instar larvae among sites is small relative to the variation in larval recruitment. This study demonstrates that locations with higher densities of odonates in the water also have higher densities of odonates on land. In addition to the densities of Gomphidae in previous life stages, water clarity helped predict larval densities, and riparian wetland vegetation helped predict emergent dragonfly densities.

  6. Knowledge of breast density and awareness of related breast cancer risk.

    Science.gov (United States)

    Manning, Mark A; Duric, Neb; Littrup, Peter; Bey-Knight, Lisa; Penner, Louis; Albrecht, Terrance L

    2013-06-01

    Little is known about women's knowledge of breast density or between-race differences in this knowledge. In the current study, we examined knowledge of breast density and awareness of its role as a breast cancer risk factor among women who had previously taken part in a breast imaging study. Seventy-seven women (54.5 % Black) returned a survey assessing perceptions and accuracy of breast density knowledge, knowledge of one's own breast density, and breast cancer risk awareness. White women had greater perceived knowledge of breast density compared to Black women; however, differences in the accuracy of definitions of breast density were due to education. Black women were less likely to know how dense their own breasts were. Black and White women both lacked awareness that having dense breast increased breast cancer risk. The results highlight the need to disseminate information regarding breast density to women, while ensuring that the information is equally accessible to both Black and White women.

  7. On the Process-Related Rivet Microstructural Evolution, Material Flow and Mechanical Properties of Ti-6Al-4V/GFRP Friction-Riveted Joints

    Directory of Open Access Journals (Sweden)

    Natascha Z. Borba

    2017-02-01

    Full Text Available In the current work, process-related thermo-mechanical changes in the rivet microstructure, joint local and global mechanical properties, and their correlation with the rivet plastic deformation regime were investigated for Ti-6Al-4V (rivet and glass-fiber-reinforced polyester (GF-P friction-riveted joints of a single polymeric base plate. Joints displaying similar quasi-static mechanical performance to conventional bolted joints were selected for detailed characterization. The mechanical performance was assessed on lap shear specimens, whereby the friction-riveted joints were connected with AA2198 gussets. Two levels of energy input were used, resulting in process temperatures varying from 460 ± 130 °C to 758 ± 56 °C and fast cooling rates (178 ± 15 °C/s, 59 ± 15 °C/s. A complex final microstructure was identified in the rivet. Whereas equiaxial α-grains with β-phase precipitated in their grain boundaries were identified in the rivet heat-affected zone, refined α′ martensite, Widmanstätten structures and β-fleck domains were present in the plastically deformed rivet volume. The transition from equiaxed to acicular structures resulted in an increase of up to 24% in microhardness in comparison to the base material. A study on the rivet material flow through microtexture of the α-Ti phase and β-fleck orientation revealed a strong effect of shear stress and forging which induced simple shear deformation. By combining advanced microstructural analysis techniques with local mechanical testing and temperature measurement, the nature of the complex rivet plastic deformational regime could be determined.

  8. On the Process-Related Rivet Microstructural Evolution, Material Flow and Mechanical Properties of Ti-6Al-4V/GFRP Friction-Riveted Joints

    Science.gov (United States)

    Borba, Natascha Z.; Afonso, Conrado R. M.; Blaga, Lucian; dos Santos, Jorge F.; Canto, Leonardo B.; Amancio-Filho, Sergio T.

    2017-01-01

    In the current work, process-related thermo-mechanical changes in the rivet microstructure, joint local and global mechanical properties, and their correlation with the rivet plastic deformation regime were investigated for Ti-6Al-4V (rivet) and glass-fiber-reinforced polyester (GF-P) friction-riveted joints of a single polymeric base plate. Joints displaying similar quasi-static mechanical performance to conventional bolted joints were selected for detailed characterization. The mechanical performance was assessed on lap shear specimens, whereby the friction-riveted joints were connected with AA2198 gussets. Two levels of energy input were used, resulting in process temperatures varying from 460 ± 130 °C to 758 ± 56 °C and fast cooling rates (178 ± 15 °C/s, 59 ± 15 °C/s). A complex final microstructure was identified in the rivet. Whereas equiaxial α-grains with β-phase precipitated in their grain boundaries were identified in the rivet heat-affected zone, refined α′ martensite, Widmanstätten structures and β-fleck domains were present in the plastically deformed rivet volume. The transition from equiaxed to acicular structures resulted in an increase of up to 24% in microhardness in comparison to the base material. A study on the rivet material flow through microtexture of the α-Ti phase and β-fleck orientation revealed a strong effect of shear stress and forging which induced simple shear deformation. By combining advanced microstructural analysis techniques with local mechanical testing and temperature measurement, the nature of the complex rivet plastic deformational regime could be determined. PMID:28772545

  9. Internal state variable plasticity-damage modeling of AISI 4140 steel including microstructure-property relations: temperature and strain rate effects

    Science.gov (United States)

    Nacif el Alaoui, Reda

    Mechanical structure-property relations have been quantified for AISI 4140 steel. under different strain rates and temperatures. The structure-property relations were used. to calibrate a microstructure-based internal state variable plasticity-damage model for. monotonic tension, compression and torsion plasticity, as well as damage evolution. Strong stress state and temperature dependences were observed for the AISI 4140 steel. Tension tests on three different notched Bridgman specimens were undertaken to study. the damage-triaxiality dependence for model validation purposes. Fracture surface. analysis was performed using Scanning Electron Microscopy (SEM) to quantify the void. nucleation and void sizes in the different specimens. The stress-strain behavior exhibited. a fairly large applied stress state (tension, compression dependence, and torsion), a. moderate temperature dependence, and a relatively small strain rate dependence.

  10. Dipeptidyl Peptidase-4 Inhibitor, Vildagliptin, Improves Trabecular Bone Mineral Density and Microstructure in Obese, Insulin-Resistant, Pre-diabetic Rats.

    Science.gov (United States)

    Charoenphandhu, Narattaphol; Suntornsaratoon, Panan; Sa-Nguanmoo, Piangkwan; Tanajak, Pongpan; Teerapornpuntakit, Jarinthorn; Aeimlapa, Ratchaneevan; Chattipakorn, Nipon; Chattipakorn, Siriporn

    2018-02-02

    Obese insulin resistance and type 2 diabetes mellitus profoundly impair bone mechanical properties and bone quality. However, because several antidiabetes drugs, especially thiazolidinediones, further aggravate bone loss in individuals with diabetes, diabetic osteopathy should not be treated by using simply any glucose-lowering agents. Recently, incretins have been reported to affect osteoblast function positively. The present study aimed to investigate the effects of vildagliptin, an inhibitor of dipeptidyl peptidase-4, on bone of rats with high-fat-diet-induced prediabetes. Male rats were fed a high-fat diet for 12 weeks to induce obese insulin resistance and then treated with vildagliptin for 4 weeks. The effects of the drug on bone were determined by microcomputed tomography and bone histomorphometry. Vildagliptin markedly improved insulin resistance in these obese insulin-resistant rats. It also significantly increased volumetric bone mineral density. Specifically, vildagliptin-treated obese insulin-resistant rats exhibited higher trabecular volumetric bone mineral density than vehicle-treated obese insulin-resistant rats, whereas cortical volumetric bone mineral density, cortical thickness and area were not changed. Bone histomorphometric analysis in a trabecular-rich area (i.e. tibial metaphysis) revealed greater trabecular bone volume and number and less trabecular separation without change in trabecular thickness, osteocyte lacunar area or cortical thickness in the vildagliptin-treated group. Vildagliptin had a beneficial effect on the bone of obese insulin-resistant rats with prediabetes, particularly at the trabecular site. Such benefit probably results from enhanced bone formation rather than from suppressed bone resorption. Copyright © 2018 Diabetes Canada. Published by Elsevier Inc. All rights reserved.

  11. Microstructural evolution of Cu-1at% Ti alloy aged in a hydrogen atmosphere and its relation with the electrical conductivity

    KAUST Repository

    Semboshi, Satoshi

    2009-04-01

    Copper alloys with titanium additions between 1 and 6 at% Ti emerge currently as attractive conductive materials for electrical and electronic commercial products, since they exhibit superior mechanical and electrical properties. However, their electrical conductivity is reduced owing to the residual amount of Ti solutes in the Cu solid solution (Cu(ss)) phase. Since Cu shows only poor reactivity with hydrogen (H), while Ti exhibits high affinity to it, we were inspired by the idea that hydrogenation of Cu-Ti alloys would influence their microstructure, resulting in a significant change of their properties. In this contribution, the influence of aging under a deuterium (D(2)) atmosphere of Cu-1 at% Ti alloys on their microstructure is investigated to explore the effects on the electrical conductivity. The specimens were investigated by means of transmission electron microscopy (TEM), field ion microscopy (FIM), computer-aided field ion image tomography (cFIIT), and atom probe tomography (APT). At an early aging stage at 623 K in a D(2) atmosphere of 0.08 Wit, ellipsoidal alpha-Cu(4)Ti precipitates are formed in the alloy, and during subsequent aging, delta-TiD(2) is competitively nucleated instead of growth of alpha-Cu(4)Ti particles. The co-precipitation of alpha-Cu(4)Ti and delta-TiD(2) efficiently reduces the Ti concentration of Cuss matrix, particularly in the later aging stages in comparison to the aging in vacuum conditions. The electrical conductivity of the alloy aged in the D(2) atmosphere increases steeply up to 48% International Annealed Copper Standard (IACS) after 1030 It, while it saturates to approximately 20% IACS in the alloy aged in vacuum. The outstanding increase of electrical conductivity during aging in D2 atmosphere can be basically explained by the reduction of Ti solute concentration in Cuss matrix. Crown Copyright (C) 2009 Published by Elsevier B.V. All rights reserved.

  12. Guaiacol hydrodeoxygenation mechanism on Pt(111): insights from density functional theory and linear free energy relations.

    Science.gov (United States)

    Lee, Kyungtae; Gu, Geun Ho; Mullen, Charles A; Boateng, Akwasi A; Vlachos, Dionisios G

    2015-01-01

    Density functional theory is used to study the adsorption of guaiacol and its initial hydrodeoxygenation (HDO) reactions on Pt(111). Previous Brønsted-Evans-Polanyi (BEP) correlations for small open-chain molecules are inadequate in estimating the reaction barriers of phenolic compounds except for the side group (methoxy) carbon-dehydrogenation. New BEP relations are established using a select group of phenolic compounds. These relations are applied to construct a potential-energy surface of guaiacol-HDO to catechol. Analysis shows that catechol is mainly produced via dehydrogenation of the methoxy functional group followed by the CHx (x<3) removal of the functional group and hydrogenation of the ring carbon, in contrast to a hypothesis of a direct demethylation path. Dehydroxylation and demethoxylation are slow, implying that phenol is likely produced from catechol but not through its direct dehydroxylation followed by aromatic carbon-ring hydrogenation. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Subalpine bumble bee foraging distances and densities in relation to flower availability.

    Science.gov (United States)

    Elliott, Susan E

    2009-06-01

    Bees feed almost exclusively on nectar and pollen from flowers. However, little is known about how food availability limits bee populations, especially in high elevation areas. Foraging distances and relationships between forager densities and resource availability can provide insights into the potential for food limitation in mobile consumer populations. For example, if floral resources are limited, bee consumers should fly farther to forage, and they should be more abundant in areas with more flowers. I estimated subalpine bumble bee foraging distances by calculating forager recapture probabilities at increasing distances from eight marking locations. I measured forager and flower densities over the flowering season in six half-hectare plots. Because subalpine bumble bees have little time to build their colonies, they may forage over short distances and forager density may not be constrained by flower density. However, late in the season, when floral resources dwindle, foraging distances may increase, and there may be stronger relationships between forager and flower densities. Throughout the flowering season, marked bees were primarily found within 100 m (and never >1,000 m) from their original marking location, suggesting that they typically did not fly far to forage. Although the density of early season foraging queens increased with early-season flower density, the density of mid- and late-season workers and males did not vary with flower density. Short foraging distances and no relationships between mid- and late-season forager and flower densities suggest that high elevation bumble bees may have ample floral resources for colony growth reproduction.

  14. Automatic temporal expectancy: a high-density event-related potential study.

    Directory of Open Access Journals (Sweden)

    Giovanni Mento

    Full Text Available How we compute time is not fully understood. Questions include whether an automatic brain mechanism is engaged in temporally regular environmental structure in order to anticipate events, and whether this can be dissociated from task-related processes, including response preparation, selection and execution. To investigate these issues, a passive temporal oddball task requiring neither time-based motor response nor explicit decision was specifically designed and delivered to participants during high-density, event-related potentials recording. Participants were presented with pairs of audiovisual stimuli (S1 and S2 interspersed with an Inter-Stimulus Interval (ISI that was manipulated according to an oddball probabilistic distribution. In the standard condition (70% of trials, the ISI lasted 1,500 ms, while in the two alternative, deviant conditions (15% each, it lasted 2,500 and 3,000 ms. The passive over-exposition to the standard ISI drove participants to automatically and progressively create an implicit temporal expectation of S2 onset, reflected by the time course of the Contingent Negative Variation response, which always peaked in correspondence to the point of S2 maximum expectation and afterwards inverted in polarity towards the baseline. Brain source analysis of S1- and ISI-related ERP activity revealed activation of sensorial cortical areas and the supplementary motor area (SMA, respectively. In particular, since the SMA time course synchronised with standard ISI, we suggest that this area is the major cortical generator of the temporal CNV reflecting an automatic, action-independent mechanism underlying temporal expectancy.

  15. Bone Mineral Density, Mechanical, Microstructural Properties and Mineral Content of the Femur in Growing Rats Fed with Cactus Opuntia ficus indica (L. Mill. (Cactaceae Cladodes as Calcium Source in Diet

    Directory of Open Access Journals (Sweden)

    Ezequiel Hernández-Becerra

    2017-02-01

    Full Text Available Mechanical, microstructural properties, mineral content and bone mineral density (BMD of the femur were evaluated in growing rats fed with Opuntia ficus indica (L. Mill. (Cactaceae cladodes at different maturity stages as calcium source. Male weanling rats were fed with cladodes at early maturity stage (25 and 60 days of age, belonging to groups N-60 and N-200, respectively and cladodes at late maturity stage (100 and 135 days of age, belonging to groups N-400 and N-600, respectively for 6 weeks. Additionally, a control group fed with calcium carbonate as calcium source was included for comparative purposes. All diets were fitted to the same calcium content (5 g/kg diet. The failure load of femurs was significantly lower (p ≤ 0.05 in groups N-60 and N-200 in comparison to N-400, N-600 and control groups. The cortical width (Ct.Wi and trabecular thickness (Tb.Th of the femurs in control and N-600 groups were significantly higher (p ≤ 0.05 than Ct.Wi and Tb.Th of femurs in groups N-60 and N-200. Trabecular separation of the femurs in N-60 and N-200 groups showed the highest values compared with all experimental groups. The highest calcium content in the femurs were observed in control, N-600 and N-400 groups; whereas the lowest phosphorus content in the bones were detected in N-200, N-600 and N-400 groups. Finally, the BMD in all experimental groups increased with age; nevertheless, the highest values were observed in N-600 and control groups during pubertal and adolescence stages. The results derived from this research demonstrate, for the first time, that the calcium found in Opuntia ficus indica cladodes is actually bioavailable and capable of improving mineral density and mechanical and microstructural properties of the bones. These findings suggest that the consumption of cladodes at late maturity stage within the diet might have a beneficial impact on bone health.

  16. VLSI electronics microstructure science

    CERN Document Server

    1982-01-01

    VLSI Electronics: Microstructure Science, Volume 4 reviews trends for the future of very large scale integration (VLSI) electronics and the scientific base that supports its development.This book discusses the silicon-on-insulator for VLSI and VHSIC, X-ray lithography, and transient response of electron transport in GaAs using the Monte Carlo method. The technology and manufacturing of high-density magnetic-bubble memories, metallic superlattices, challenge of education for VLSI, and impact of VLSI on medical signal processing are also elaborated. This text likewise covers the impact of VLSI t

  17. The relation between the column density structures and the magnetic field orientation in the Vela C molecular complex

    Science.gov (United States)

    Soler, J. D.; Ade, P. A. R.; Angilè, F. E.; Ashton, P.; Benton, S. J.; Devlin, M. J.; Dober, B.; Fissel, L. M.; Fukui, Y.; Galitzki, N.; Gandilo, N. N.; Hennebelle, P.; Klein, J.; Li, Z.-Y.; Korotkov, A. L.; Martin, P. G.; Matthews, T. G.; Moncelsi, L.; Netterfield, C. B.; Novak, G.; Pascale, E.; Poidevin, F.; Santos, F. P.; Savini, G.; Scott, D.; Shariff, J. A.; Thomas, N. E.; Tucker, C. E.; Tucker, G. S.; Ward-Thompson, D.

    2017-07-01

    We statistically evaluated the relative orientation between gas column density structures, inferred from Herschel submillimetre observations, and the magnetic field projected on the plane of sky, inferred from polarized thermal emission of Galactic dust observed by the Balloon-borne Large-Aperture Submillimetre Telescope for Polarimetry (BLASTPol) at 250, 350, and 500 μm, towards the Vela C molecular complex. First, we find very good agreement between the polarization orientations in the three wavelength-bands, suggesting that, at the considered common angular resolution of 3.´0 that corresponds to a physical scale of approximately 0.61 pc, the inferred magnetic field orientation is not significantly affected by temperature or dust grain alignment effects. Second, we find that the relative orientation between gas column density structures and the magnetic field changes progressively with increasing gas column density, from mostly parallel or having no preferred orientation at low column densities to mostly perpendicular at the highest column densities. This observation is in agreement with previous studies by the Planck collaboration towards more nearby molecular clouds. Finally, we find a correspondencebetween (a) the trends in relative orientation between the column density structures and the projected magnetic field; and (b) the shape of the column density probability distribution functions (PDFs). In the sub-regions of Vela C dominated by one clear filamentary structure, or "ridges", where the high-column density tails of the PDFs are flatter, we find a sharp transition from preferentially parallel or having no preferred relative orientation at low column densities to preferentially perpendicular at highest column densities. In the sub-regions of Vela C dominated by several filamentary structures with multiple orientations, or "nests", where the maximum values of the column density are smaller than in the ridge-like sub-regions and the high-column density

  18. Modeling and control of the current density profile in Tokamaks and its relation to electron transport

    International Nuclear Information System (INIS)

    Zucca, C.

    2009-04-01

    The current density in tokamak plasmas strongly affects transport phenomena, therefore its understanding and control represent a crucial challenge for controlled thermonuclear fusion. Within the vast framework of tokamak studies, three topics have been tackled in the course of the present thesis: first, the modelling of the current density evolution in electron Internal Transport Barrier (eITB) discharges in the Tokamak à Configuration Variable (TCV); second, the study of current diffusion and inversion of electron transport properties observed during Swing Electron Cyclotron Current Drive (Swing ECCD) discharges in TCV; third, the analysis of the current density tailoring obtained by local ECCD driven by the improved EC system for sawtooth control and reverse shear scenarios in the International Thermonuclear Experimental Reactor (ITER). The work dedicated to the study of eITBs in TCV has been undertaken to identify which of the main parameters, directly related to the current density, played a relevant role in the confinement improvement created during these advanced scenarios. In this context, the current density has to be modeled, there being no measurement currently available on TCV. Since the Rebut-Lallia-Watkins (RLW) model has been validated on TCV ohmic heated plasmas, the corresponding scaling factor has often been used as a measure of improved confinement on TCV. The many interpretative simulations carried on different TCV discharges have shown that the thermal confinement improvement factor, H RLW , linearly increases with the absolute value of the minimum shear outside ρ > 0.3, ρ indicating a normalized radial coordinate. These investigations, performed with the transport code ASTRA, therefore confirmed a general observation, formulated through previous studies, that the formation of the transport barrier is correlated with the magnetic shear reversal. This was, indeed, found to be true in all cases studied, regardless of the different heating and

  19. Uncertainty relations and reduced density matrices: Mapping many-body quantum mechanics onto four particles

    Science.gov (United States)

    Mazziotti, David A.; Erdahl, Robert M.

    2001-04-01

    For the description of ground-state correlation phenomena an accurate mapping of many-body quantum mechanics onto four particles is developed. The energy for a quantum system with no more than two-particle interactions may be expressed in terms of a two-particle reduced density matrix (2-RDM), but variational optimization of the 2-RDM requires that it corresponds to an N-particle wave function. We derive N-representability conditions on the 2-RDM that guarantee the validity of the uncertainty relations for all operators with two-particle interactions. One of these conditions is shown to be necessary and sufficient to make the RDM solutions of the dispersion condition equivalent to those from the contracted Schrödinger equation (CSE) [Mazziotti, Phys. Rev. A 57, 4219 (1998)]. In general, the CSE is a stronger N-representability condition than the dispersion condition because the CSE implies the dispersion condition as well as additional N-representability constraints from the Hellmann-Feynman theorem. Energy minimization subject to the representability constraints is performed for a boson model with 10, 30, and 75 particles. Even when traditional wave-function methods fail at large perturbations, the present method yields correlation energies within 2%.

  20. Increased power spectral density in resting-state pain-related brain networks in fibromyalgia.

    Science.gov (United States)

    Kim, Ji-Young; Kim, Seong-Ho; Seo, Jeehye; Kim, Sang-Hyon; Han, Seung Woo; Nam, Eon Jeong; Kim, Seong-Kyu; Lee, Hui Joong; Lee, Seung-Jae; Kim, Yang-Tae; Chang, Yongmin

    2013-09-01

    Fibromyalgia (FM), characterized by chronic widespread pain, is known to be associated with heightened responses to painful stimuli and atypical resting-state functional connectivity among pain-related regions of the brain. Previous studies of FM using resting-state functional magnetic resonance imaging (rs-fMRI) have focused on intrinsic functional connectivity, which maps the spatial distribution of temporal correlations among spontaneous low-frequency fluctuation in functional MRI (fMRI) resting-state data. In the current study, using rs-fMRI data in the frequency domain, we investigated the possible alteration of power spectral density (PSD) of low-frequency fluctuation in brain regions associated with central pain processing in patients with FM. rsfMRI data were obtained from 19 patients with FM and 20 age-matched healthy female control subjects. For each subject, the PSDs for each brain region identified from functional connectivity maps were computed for the frequency band of 0.01 to 0.25 Hz. For each group, the average PSD was determined for each brain region and a 2-sample t test was performed to determine the difference in power between the 2 groups. According to the results, patients with FM exhibited significantly increased frequency power in the primary somatosensory cortex (S1), supplementary motor area (SMA), dorsolateral prefrontal cortex, and amygdala. In patients with FM, the increase in PSD did not show an association with depression or anxiety. Therefore, our findings of atypical increased frequency power during the resting state in pain-related brain regions may implicate the enhanced resting-state baseline neural activity in several brain regions associated with pain processing in FM. Copyright © 2013 International Association for the Study of Pain. Published by Elsevier B.V. All rights reserved.

  1. B-vitamin status in relation to bone mineral density in treated celiac disease patients.

    Science.gov (United States)

    Clarke, Michelle; Ward, Mary; Dickey, William; Hoey, Leane; Molloy, Anne M; Waldron, Lisa; Varghese, Abraham; McCann, Adrian; Blayney, Jaine K; McNulty, Helene

    2015-08-01

    Patients with celiac disease (CD) are at increased risk of osteoporosis and compromised B-vitamin status. Emerging evidence supports a beneficial role of folate and the metabolically related B-vitamins in bone health in generally healthy adults, but no previous study has investigated this in CD patients. The aim of the current study was to examine the relationship of folate, vitamins B12, B6 and B2 (riboflavin), and the related metabolite homocysteine, with bone mineral density (BMD) in CD patients. Of the 400 treated adult CD patients invited to participate, 110 responded and met the eligibility criteria for study participation. BMD was measured using dual energy X-ray absorptiometry scanning at the lumbar spine (L1-L4), femoral neck, and total hip sites. Biomarker status of the relevant B-vitamins and homocysteine, and dietary B-vitamin intakes, were measured. The significant predictors of low BMD were increasing age (B = 0.080, p B = 0.072, p = 0.004), whereas no significant relationship with serum 25-hydroxyvitamin D (B = 0.093, p = 0.928) was observed. Following adjustment for these predictors, serum vitamin B12 (but no other B-vitamin biomarker) was found to be a significant determinant of BMD at the femoral neck (β = 0.416, p = 0.011) and total hip (β = 0.327, p = 0.049) in men only. No significant relationships were found between any of the B-vitamin biomarkers investigated and BMD (at any measured site) in women. These findings add to current evidence suggesting a potential role of vitamin B12 in BMD, particularly in men, and show such a relationship for the first time in CD patients.

  2. Lactoperoxidase catalyzed radioiodination of cell surface immunoglobulin: incorporated radioactivity may not reflect relative cell surface Ig density

    International Nuclear Information System (INIS)

    Wilder, R.L.; Yuen, C.C.; Mage, R.G.

    1979-01-01

    Rabbit and mouse splenic lymphocytes were radioiodinated by the lactoperoxidase technique, extracted with non-ionic detergent, immunoprecipitated with high titered rabbit anti-kappa antisera, and compared by SDS-PAGE. Mouse sIg peaks were reproducibly larger in size than rabbit sIg peaks (often greater than 10 times). Neither differences in incorporation of label into the rabbit cell surface, nor differences in average sIg density explain this result. Total TCA-precipitable radioactivity was similar in each species. Estimation of the relative amounts of sIg in the mouse and rabbit showed similar average sIg densities. Differences in detergent solubility, proteolytic lability, or antisera used also do not adequately account for this difference. Thus, these data indicate that radioactivity incorporated after lactoperoxidase catalyzed cell surface radioiodination may not reflect cell surface Ig density. Conclusions about cell surface density based upon relative incorporation of radioactivity should be confirmed by other approaches

  3. Processing, microstructure, leaching, and long-term stability studies related to titanate high-level waste forms

    International Nuclear Information System (INIS)

    Dosch, R.G.; Headley, T.J.; Northrup, C.J.; Hlava, P.F.

    1983-05-01

    A process leading to titanate-based waste forms for commercial high-level nuclear waste is described. Radionuclides are fixed on hydrous calcium titanate by ion exchange/sorption reactions and the material is converted to a dense, ceramic form by hot pressing. Transmission electron microscopy-electron microprobe characterization was done to determine the effects of compositional changes and process variations on microstructure. Leaching studies in the range of 22 to 150 0 C and pH 2 to 12 were done to assess the effects of the same variables on leaching behavior. Samples of a reference borosilicate glass waste form were leached under the same conditions to provide a direct comparison between the two waste forms. Lead-ion implantation was used to simulate long-term α-recoil damage in the crystalline titanate phases. Comparison of α-recoil damage in natural minerals with damage induced in synthesized samples of the same mineral suggest that Pb-ion implantation is a valid technique for simulating α-recoil effects. All the titanate phases sustained significant lattice damage at equivalent α-doses of 1 x 10 19 /cm 3 ; however, Rutherford backscattering and transmission electron microscopy studies showed that the damage did not result in significant matrix dissolution in these leaching tests

  4. Microhardness variation and related microstructure in Al-Cu alloys prepared by HF induction melting and RF sputtering

    Science.gov (United States)

    Boukhris, N.; Lallouche, S.; Debili, M. Y.; Draissia, M.

    2009-03-01

    The materials under consideration are binary aluminium-copper alloys (10 at% to 90.3 at%Cu) produced by HF melting and RF magnetron sputtering. The resulting micro structures have been observed by standard metallographic techniques, X-ray powder diffraction, scanning electron microscopy and transmission electron microscopy. Vickers microhardness of bulk Al-Cu alloys reaches a maximum of 1800 MPa at 70.16 at%Cu. An unexpected metastable θ ' phase has been observed within aluminium grain in Al-37 at%Cu. The mechanical properties of a family of homogeneous Al{1-x}Cu{x} (0 Al-Cu targets have been investigated. The as-deposited microstructures for all film compositions consisted of a mixture of the two expected face-centred-cubic (fcc) Al solid solution and tetragonal θ (Al{2}Cu) phases. The microhardness regularly increases and the grain size decreases both with copper concentration. This phenomenon of significant mechanical strengthening of aluminium by means of copper is essentially due to a combination between solid solution effects and grain size refinement. This paper reports some structural features of different Al-Cu alloys prepared by HF melting and RF magnetron on glass substrate sputtering.

  5. The microstructure of type 304 stainless steel implanted with titanium and carbon and its relation to friction and wear tests

    International Nuclear Information System (INIS)

    Follstaedt, D.M.; Pope, L.E.; Knapp, J.A.; Picraux, S.T.; Yost, F.G.

    1983-01-01

    The authors have used transmission electron microscopy to examine the microstructure of type 304 stainless steel which was ion implanted with high doses (2 X 10 17 atoms cm -2 ) of titanium and carbon. It is found that the resulting surface alloy is an amorphous phase similar to that observed when pure iron is identically implanted. This result is important for identifying the mechanisms by which the coefficient of friction and the wear depth are reduced in unlubricated pin-on-disc tests of type 304 stainless steel implanted with titanium and carbon. The effect of temperature on the amorphous alloy during annealing in the microscope has also been examined. It is found that devitrification begins after 15 min at 500 0 C and that the alloy fully crystallizes into f.c.c., b.c.c. and TiC phases after 15 min at 650 0 C. A comparison of mechanical test results from devitrified specimens with results from amorphous specimens demonstrates that the reduction in the coefficient of friction correlates with the presence of the amorphous layer, whereas the reduction in the wear depth is obtained for both amorphous and crystalline alloys. (Auth.)

  6. Anatomical traits related to stress in high density populations of Typha angustifolia L. (Typhaceae

    Directory of Open Access Journals (Sweden)

    F. F. Corrêa

    Full Text Available Abstract Some macrophytes species show a high growth potential, colonizing large areas on aquatic environments. Cattail (Typha angustifolia L. uncontrolled growth causes several problems to human activities and local biodiversity, but this also may lead to competition and further problems for this species itself. Thus, the objective of this study was to investigate anatomical modifications on T. angustifolia plants from different population densities, once it can help to understand its biology. Roots and leaves were collected from natural populations growing under high and low densities. These plant materials were fixed and submitted to usual plant microtechnique procedures. Slides were observed and photographed under light microscopy and images were analyzed in the UTHSCSA-Imagetool software. The experimental design was completely randomized with two treatments and ten replicates, data were submitted to one-way ANOVA and Scott-Knott test at p<0.05. Leaves from low density populations showed higher stomatal density and index. These modifications on stomatal characteristics were more evident on the leaf abaxial surface. Plants from low density populations showed thicker mesophyll and higher proportion of aerenchymal area. Roots from low density populations showed a higher proportion of the vascular cylinder. Whereas, plants from higher density populations showed greater thickness of the endodermis, exodermis, phloem and root cortex. Higher density populations showed a higher proportion of aerenchymal gaps in the root cortex. Therefore, cattail plants from populations growing under high density population show anatomical traits typical of plants under stress, which promotes the development of less functional anatomical modifications to aquatic environments.

  7. Bond index: relation to second-order density matrix and charge fluctuations

    International Nuclear Information System (INIS)

    Giambiagi, M.S. de; Giambiagi, M.; Jorge, F.E.

    1985-01-01

    It is shown that, in the same way as the atomic charge is an invariant built from the first-order density matrix, the closed-shell generalized bond index is an invariant associated with the second-order reduced density matrix. The active charge of an atom (sum of bond indices) is shown to be the sum of all density correlation functions between it and the other atoms in the molecule; similarly, the self-charge is the fluctuation of its total charge. (Author) [pt

  8. Artificial Microstructures to Investigate Microstructure-Property Relationships in Metallic Glasses

    Science.gov (United States)

    Sarac, Baran

    , size, spacing, volume fraction of the second phase, and strength and toughness of the interface. Previous studies suggest these contributions, however, do not provide quantitative experimental evidence. Within this thesis, we paid tribute to the complexity of the toughening mechanism by revealing the correlation between plastic zone size (Rp) and second phase spacing (s ), and the results guided us how to design elasticity through the second phase morphology (AB pore stacking) in MG heterostructures. The second phase elasticity and shear modulus were also found to be contributing to the overall elasticity. We identified the pores' ratio of diameter to spacing (d/s) as one of the major factors controlling the mechanical properties of MG hetero structures, which is most efficient when d/s ≈ 1. Effectiveness of MG heterostructures also depends on the size of the sample, w, in comparison to s. Our experimental findings illuminate the complexity in MG composites, which can be resolved with our artificial microstructure approach. Another subject where we use artificial microstructures is to identify the effect of length scales on structural properties of MG heterostructures. MG structures can be fabricated over 7 orders of magnitude length scale (nm to cm), where the effect of the feature size determines whether the deformation will be homogenous throughout the sample, it will be localized into shear bands, or it will not show any shear bands (no plasticity) during bending and tension. We investigated the deformation modes of Zr-based MGs in hexagonal cellular structures controlled by the relative density, and revealed three distinctive deformation regions: collective buckling, local failure, and global failure which originate from size effects in metallic glasses. The relative density of ˜25.0% was determined as the ideal relative density for energy absorption, strength and plasticity in MG cellular structures. Besides two specific examples studied in detail here, the

  9. Contribution to the Study of the Relation between Microstructure and Electrochemical Behavior of Iron-Based FeCoC Ternary Alloys

    Directory of Open Access Journals (Sweden)

    Farida Benhalla-Haddad

    2012-01-01

    Full Text Available This work deals with the relation between microstructure and electrochemical behavior of four iron-based FeCoC ternary alloys. First, the arc-melted studied alloys were characterized using differential thermal analyses and scanning electron microscopy. The established solidification sequences of these alloys show the presence of two primary crystallization phases (δ(Fe and graphite as well as two univariante lines : peritectic L+(Fe↔(Fe and eutectic L↔(Fe+Cgraphite. The ternary alloys were thereafter studied in nondeaerated solution of 10−3 M NaHCO3 + 10−3 M Na2SO4, at 25°C, by means of the potentiodynamic technique. The results indicate that the corrosion resistance of the FeCoC alloys depends on the carbon amount and the morphology of the phases present in the studied alloys.

  10. Genetic analysis of male reproductive success in relation to density in the zebrafish, Danio rerio

    Directory of Open Access Journals (Sweden)

    Jordan William C

    2006-04-01

    Full Text Available Abstract Background We used behavioural and genetic data to investigate the effects of density on male reproductive success in the zebrafish, Danio rerio. Based on previous measurements of aggression and courtship behaviour by territorial males, we predicted that they would sire more offspring than non-territorial males. Results Microsatellite analysis of paternity showed that at low densities territorial males had higher reproductive success than non-territorial males. However, at high density territorial males were no more successful than non-territorials and the sex difference in the opportunity for sexual selection, based on the parameter Imates, was low. Conclusion Male zebrafish exhibit two distinct mating tactics; territoriality and active pursuit of females. Male reproductive success is density dependent and the opportunity for sexual selection appears to be weak in this species.

  11. Copepod swimming behavior, respiration, and expression of stress-related genes in response to high stocking densities

    DEFF Research Database (Denmark)

    Nilsson, Birgitte; Jakobsen, Hans Henrik; Stief, Peter

    2017-01-01

    is problematic for calanoid copepod species like Acartia tonsa. In the present study, we evaluated the response of copepods experiencing stress under high-density conditions by assessing the acute stress level of A. tonsa. Control density was at 100 ind. L−1 while the treatments were increased stepwise up to 10......,000 ind. L−1. Three biological/physiological end-points were studied: swimming behavior, respiration rate and expression level of stress-related genes. None of the elevated densities caused any significant change in swimming behavior, respiration rate or gene expression level. This study suggests...... that adults of A. tonsa do not exhibit any measurable acute stress response when exposed to high culture densities for 12 h....

  12. Gender-related differences in the apparent timing of skeletal density bands in the reef-building coral Siderastrea siderea

    Science.gov (United States)

    Carricart-Ganivet, J. P.; Vásquez-Bedoya, L. F.; Cabanillas-Terán, N.; Blanchon, P.

    2013-09-01

    Density banding in skeletons of reef-building corals is a valuable source of proxy environmental data. However, skeletal growth strategy has a significant impact on the apparent timing of density-band formation. Some corals employ a strategy where the tissue occupies previously formed skeleton during as the new band forms, which leads to differences between the actual and apparent band timing. To investigate this effect, we collected cores from female and male colonies of Siderastrea siderea and report tissue thicknesses and density-related growth parameters over a 17-yr interval. Correlating these results with monthly sea surface temperature (SST) shows that maximum skeletal density in the female coincides with low winter SSTs, whereas in the male, it coincides with high summer SSTs. Furthermore, maximum skeletal densities in the female coincide with peak Sr/Ca values, whereas in the male, they coincide with low Sr/Ca values. Both results indicate a 6-month difference in the apparent timing of density-band formation between genders. Examination of skeletal extension rates also show that the male has thicker tissue and extends faster, whereas the female has thinner tissue and a denser skeleton—but both calcify at the same rate. The correlation between extension and calcification, combined with the fact that density banding arises from thickening of the skeleton throughout the depth reached by the tissue layer, implies that S. siderea has the same growth strategy as massive Porites, investing its calcification resources into linear extension. In addition, differences in tissue thicknesses suggest that females offset the greater energy requirements of gamete production by generating less tissue, resulting in differences in the apparent timing of density-band formation. Such gender-related offsets may be common in other corals and require that environmental reconstructions be made from sexed colonies and that, in fossil corals where sex cannot be determined

  13. Numerical investigations on contactless methods for measuring critical current density in HTS: application of modified constitutive-relation method

    International Nuclear Information System (INIS)

    Kamitani, A.; Takayama, T.; Itoh, T.; Ikuno, S.

    2011-01-01

    A fast method is proposed for calculating the shielding current density in an HTS. The J-E constitutive relation is modified so as not to change the solution. A numerical code is developed on the basis of the proposed method. The permanent magnet method is successfully simulated by means of the code. A fast method has been proposed for calculating the shielding current density in a high-temperature superconducting thin film. An initial-boundary-value problem of the shielding current density cannot be always solved by means of the Runge-Kutta method even when an adaptive step-size control algorithm is incorporated to the method. In order to suppress an overflow in the algorithm, the J-E constitutive relation is modified so that its solution may satisfy the original constitutive relation. A numerical code for analyzing the shielding current density has been developed on the basis of this method and, as an application of the code, the permanent magnet method for measuring the critical current density has been investigated numerically.

  14. The effects of additives on the microstructure and sinterability of molybdenum oxide - study of related solid solutions

    International Nuclear Information System (INIS)

    Kassem, M.

    2006-01-01

    This study focuses on the phase transformation induced during mixing a fixed quantity of MoO 3 with various concentration of V 2 O 5 , Bn 2 O 5 , Al 2 O 3 and pure aluminium. These concentrations are 2, 3, 4, 5, 10, 20, 40 and 50%. Employing several physical techniques such as x-ray powder diffraction, FTIR and DTA, different solid solution were identified. Also the compressibility and sintering of these solid solutions have been studied via the variation of the density of pellets prepared from these solid solutions (Author)

  15. High-density 3D graphene-based monolith and related materials, methods, and devices

    Energy Technology Data Exchange (ETDEWEB)

    Worsley, Marcus A.; Baumann, Theodore F.; Biener, Juergen; Charnvanichborikarn, Supakit; Kucheyev, Sergei; Montalvo, Elizabeth; Shin, Swanee; Tylski, Elijah

    2017-03-21

    A composition comprising at least one high-density graphene-based monolith, said monolith comprising a three-dimensional structure of graphene sheets crosslinked by covalent carbon bonds and having a density of at least 0.1 g/cm.sup.3. Also provided is a method comprising: preparing a reaction mixture comprising a suspension and at least one catalyst, said suspension selected from a graphene oxide (GO) suspension and a carbon nanotube suspension; curing the reaction mixture to produce a wet gel; drying the wet gel to produce a dry gel, said drying step is substantially free of supercritical drying and freeze drying; and pyrolyzing the dry gel to produce a high-density graphene-based monolith. Exceptional combinations of properties are achieved including high conductive and mechanical properties.

  16. Microstructural changes during creep and life assessment of Mod.9Cr-1Mo steel

    International Nuclear Information System (INIS)

    Sawada, Kota; Maruyama, Kouichi; Komine, Ryuji; Nagae, Yuji.

    1997-01-01

    Several microstructural changes take place in a material during the course of creep. These changes can be a measure of creep life. In this paper, microstructural changes in Mod.9Cr-1Mo steel were studied and it was examined which is a good measure of creep life. Microscopic structural changes, such as void growth, lath structure uniformly oriented to the tensile axis and elongation of grains, are evident only in the necked portion of ruptured specimens. These macroscopic structural changes are not useful for creep life assessment. Lath width increases and dislocation density within lath decreases with increasing creep duration. These changes in dislocation substructure start in the early stage of creep life, and cause the increase of strain rate in the tertiary creep stage. The lath width and the dislocation density reach a saturated value before rupture. The saturated values are independent of temperature, and uniquely related to creep stress normalized by shear modulus. The extent of these microstructural changes are greater at lower stresses under which the material is practically used. These facts suggest that the lath width and the dislocation density within lath can be a useful measure of creep life. Hardness of crept specimens is closely related to the lath width and the dislocation density within lath. The changes of these microstructural features can be evaluated by the measurement of hardness. (author)

  17. Altered microstructural connectivity of the superior and middle cerebellar peduncles are related to motor dysfunction in children with diffuse periventricular leucomalacia born preterm: A DTI tractography study

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Shanshan, E-mail: jelly_66@126.com; Fan, Guo Guang, E-mail: cjr.fanguoguang@vip.163.com; Xu, Ke, E-mail: cjr.xuke@vip.163.com; Wang, Ci, E-mail: xiangxuehai19850224@yahoo.cn

    2014-06-15

    Purpose: To investigate the microstructural integrity of superior cerebellar peduncles (SCP) and middle cerebellar peduncles (MCP) by using DTI tractography method, and further to detect whether the microstructural integrity of these major cerebellar pathways is related to motor function in children with diffuse periventricular leucomalacia (PVL) born preterm. Materials and methods: 46 children with diffuse PVL (30 males and 16 females; age range 3–48 months; mean age 22.4 ± 6.7 months; mean gestational age 30.5 ± 2.2 weeks) and 40 healthy controls (27 males and 13 females; age range 3.5–48 months; mean age 22.1 ± 5.8 months) were enrolled in this study. DTI outcome measurements, fractional anisotropy (FA), for the SCP, MCP and cortical spinal tract (CST) were calculated. The gross motor function classification system (GMFCS) was used for assessing motor functions. Results: Compared to the controls, patients with diffuse PVL had a significantly lower FA in bilateral SCP, MCP and CST. There was a significant negative correlation between GMFCS levels and FA in bilateral SCP, MCP and CST in the patients group. In addition, significant inverse correlation of FA value was found between not only the contralateral but also the ipsilateral CST and SCP/MCP. Conclusions: These findings suggest that the injury of SCP and MCP may contribute to the motor dysfunction of diffuse PVL. Moreover, the correlations we found between supratentorial and subtentorial injured white matter extend our knowledge about the cerebro-cerebellar white matter interaction in children with diffuse PVL.

  18. Altered microstructural connectivity of the superior and middle cerebellar peduncles are related to motor dysfunction in children with diffuse periventricular leucomalacia born preterm: A DTI tractography study

    International Nuclear Information System (INIS)

    Wang, Shanshan; Fan, Guo Guang; Xu, Ke; Wang, Ci

    2014-01-01

    Purpose: To investigate the microstructural integrity of superior cerebellar peduncles (SCP) and middle cerebellar peduncles (MCP) by using DTI tractography method, and further to detect whether the microstructural integrity of these major cerebellar pathways is related to motor function in children with diffuse periventricular leucomalacia (PVL) born preterm. Materials and methods: 46 children with diffuse PVL (30 males and 16 females; age range 3–48 months; mean age 22.4 ± 6.7 months; mean gestational age 30.5 ± 2.2 weeks) and 40 healthy controls (27 males and 13 females; age range 3.5–48 months; mean age 22.1 ± 5.8 months) were enrolled in this study. DTI outcome measurements, fractional anisotropy (FA), for the SCP, MCP and cortical spinal tract (CST) were calculated. The gross motor function classification system (GMFCS) was used for assessing motor functions. Results: Compared to the controls, patients with diffuse PVL had a significantly lower FA in bilateral SCP, MCP and CST. There was a significant negative correlation between GMFCS levels and FA in bilateral SCP, MCP and CST in the patients group. In addition, significant inverse correlation of FA value was found between not only the contralateral but also the ipsilateral CST and SCP/MCP. Conclusions: These findings suggest that the injury of SCP and MCP may contribute to the motor dysfunction of diffuse PVL. Moreover, the correlations we found between supratentorial and subtentorial injured white matter extend our knowledge about the cerebro-cerebellar white matter interaction in children with diffuse PVL

  19. Microstructural study of the interface in laser-clad Ni-Al bronze on Al alloy AA333 and its relation to cracking

    Science.gov (United States)

    Liu, Y.; Mazumder, J.; Shibata, K.

    1995-06-01

    The interface toughness between a laser clad and the substrate determines whether the cladding is useful for engineering application. The objective of this investigation is to correlate the interface properties of laser-clad Ni-AI bronze on Al alloy AA333 with the microstructure and crystal structure of the interface. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) combined with energy-dispersive X-ray spectroscopy (EDX) are used to examine the interface. In a good clad track, the interface is an irregular curved zone with a varying width (occasionally keyholing structure) from 30 to 150 μm. A compositional transition from the Cu-rich clad (83 wt pct Cu) to the Al-rich substrate (3.2 wt pct Cu) occurs across this interface. Three phases in the interface are identified in TEM: Al solid solution, θ phase, and γ1 phase, as described in the Cu-Al binary phase diagram. In a good clad track, the θ and γ1 phases are distributed in the Al solid solution. In a clad track with cracks, the interface structure spreads to a much larger scale from 300 μm to the whole clad region. Large areas of θ and γ1 phases are observed. The mechanism of cracking at the interface is related to the formation of a twophase region of θ and γ1 phases. To understand the microstructure, a nonequilibrium quasibinary Cu-Al phase diagram is proposed and compared with the equilibrium binary Cu-Al phase diagram. It is found that the occurrence of many phases such as η1η2, ζ1, ζ2, ɛ1, ɛ2, γ0, β0, and β, as described in the equilibrium binary Cu-Al phase diagram, is suppressed by either the cladding process or by the alloying elements. The three identified phases (Al solid solution, θ phase, and γ1, phase) showed significant extension of solubility.

  20. Relation of bone mineral density with homocysteine and cathepsin K levels in postmenopausal women

    Directory of Open Access Journals (Sweden)

    Madhukar Mittal

    2018-01-01

    Full Text Available Background: Homocysteine (HCY interferes with collagen cross-linking in bones and stimulates osteoclast activity. The activated osteoclasts secrete cathepsin K (CathK, a cysteine protease, in eminent quantity during bone resorption. Hyperhomocysteinemia may effect bone mineral density (BMD through CathK. We, therefore, examined the relation between HCY and BMD along with CathK, 25-hydroxyvit-D (25[OH]D, intact parathyroid hormone (iPTH, and Vitamin B12. Materials and Methods: We recruited a total of 93 postmenopausal women between the age group of 45–60 years, attending the Endocrinology outpatient department at King George's Medical University, Lucknow. BMD was done by DXA scan using Hologic QDR1000 system. Based on the WHO criteria, patients were segregated into three groups as follows; normal bone mass, osteopenia, and osteoporosis. All women underwent routine biochemical laboratory parameters, HCY, Vitamin B12, and CathK levels. Results: Among 93 postmenopausal women, 56% (52 had osteoporosis. Nineteen percent (18 had normal BMD (mean age, 53.22 ± 8.5 years and 23 (25% had osteopenia (mean age 52.86 ± 6.67 years. The mean age in the osteoporetic group was 56.2 ± 6.9 years. The median (interquartile range levels of HCY in the three groups were 14.5 μmol/L (12.2–24.7, 15.05 μmol/L (12.1–19.9 and 13.2 μmol/L (10.3–17.0, respectively. CathK levels were similar in three groups 7.6 ng/ml (7.0–80.5, 8.3 ng/ml (7.3–8.5, and 8.6 ng/ml (7.2–8.9. Both HCY and CathK were found positively associated with serum phosphorus (r = 0.584, P < 2.01 and r = 0.249, P < 0.05, respectively. Levels of HCY positively correlate with PTH (r = 0.303, P < 0.01 and inversely with Vitamin B12 (r = −0.248, P < 0.05. No significant association was seen between CathK level and 25(OH D, iPTH, serum calcium. Conclusion: Low bone mass by DXA is a significant problem in postmenopausal females. HCY and CathK do not reliably correlate with bone loss in

  1. High-Density Lipoprotein Function in Exudative Age-Related Macular Degeneration.

    Directory of Open Access Journals (Sweden)

    Laura Pertl

    Full Text Available High-density lipoproteins (HDL have long been implicated in the pathogenesis of age-related macular degeneration (AMD. However, conflicting results have been reported with regard to the associations of AMD with HDL-cholesterol levels. The present study is the first to assess HDL composition and metrics of HDL function in patients with exudative AMD and control patients.Blood samples were collected from 29 patients with exudative AMD and 26 age-matched control patients. Major HDL associated apolipoproteins were determined in apoB-depleted serum by immunoturbidimetry or ELISA, HDL-associated lipids were quantified enzymatically. To get an integrated measure of HDL quantity and quality, we assessed several metrics of HDL function, including cholesterol efflux capacity, anti-oxidative and anti-inflammatory activities using apoB-depleted serum from study participants.In our study, we observed that the HDL associated acute phase protein serum amyloid A (SAA was significantly increased in AMD patients (p<0.01, whereas all other assessed apolipoproteins including ApoA-I, apoA-II, apoC-II, apoC-III and apoE as well as major HDL associated lipids were not altered. HDL efflux capacity, anti-oxidative capacity and arylesterase activity were not different in AMD patients when compared with the control group. The ability of apoB-depleted serum to inhibit monocyte NF-κB expression was significantly improved in AMD patients (mean difference (MD -5.6, p<0.01. Moreover, lipoprotein-associated phospholipase A2 activity, a marker of vascular inflammation, was decreased in AMD subjects (MD -24.1, p<0.01.The investigated metrics of HDL composition and HDL function were not associated with exudative AMD in this study, despite an increased content of HDL associated SAA in AMD patients. Unexpectedly, anti-inflammatory activity of apoB-depleted serum was even increased in our study. Our data suggest that the investigated parameters of serum HDL function showed no

  2. Calculation of the phonon density of states and related thermodynamic properties for trigonal selenium

    DEFF Research Database (Denmark)

    Hansen, Flemming Yssing; Alldredge, G. P.; McMurry, H. L.

    1983-01-01

    The phonon density of states for trigonal selenium has been calculated on the basis of a short range force model giving good overall agreement with experimental room temperature phonon dispersion data. A qualitative comparison with an experimental determination of the phonon density of states shows...... similarities in the gross features, but the experimental data lacks many of the finer details shown by the theoretical results due to resolution effects. The lattice dynamical contribution to the heat capacity CV is calculated and is found to be in good agreement with experimental determinations of Cp after...

  3. Online learning from input versus offline memory evolution in adult word learning: effects of neighborhood density and phonologically related practice.

    Science.gov (United States)

    Storkel, Holly L; Bontempo, Daniel E; Pak, Natalie S

    2014-10-01

    In this study, the authors investigated adult word learning to determine how neighborhood density and practice across phonologically related training sets influence online learning from input during training versus offline memory evolution during no-training gaps. Sixty-one adults were randomly assigned to learn low- or high-density nonwords. Within each density condition, participants were trained on one set of words and then were trained on a second set of words, consisting of phonological neighbors of the first set. Learning was measured in a picture-naming test. Data were analyzed using multilevel modeling and spline regression. Steep learning during input was observed, with new words from dense neighborhoods and new words that were neighbors of recently learned words (i.e., second-set words) being learned better than other words. In terms of memory evolution, large and significant forgetting was observed during 1-week gaps in training. Effects of density and practice during memory evolution were opposite of those during input. Specifically, forgetting was greater for high-density and second-set words than for low-density and first-set words. High phonological similarity, regardless of source (i.e., known words or recent training), appears to facilitate online learning from input but seems to impede offline memory evolution.

  4. Brent goose colonies near snowy owls: Internest distances in relation to breeding arctic fox densities

    NARCIS (Netherlands)

    Kharitonov, S.P.; Ebbinge, B.S.; De Fouw, J.

    2013-01-01

    It was shown that in the years when the numbers of the Arctic foxes are high, even though the lemming numbers are high as well, Brent geese nest considerably closer to owls' nests than in the years with low Arctic fox numbers. At values of the Arctic fox densities greater than one breeding pair per

  5. Relative electron density determination using a physics based parameterization of photon interactions in medical DECT

    NARCIS (Netherlands)

    van Abbema, Joanne K.; van Goethem, Marc-Jan; Greuter, Marcel J. W.; van der Schaaf, Arjen; Brandenburg, Sytze; van der Graaf, Emiel R.

    2015-01-01

    Radiotherapy and particle therapy treatment planning require accurate knowledge of the electron density and elemental composition of the tissues in the beam path to predict the local dose deposition. We describe a method for the analysis of dual energy computed tomography (DECT) images that provides

  6. Feeding and growth of larval herring,Clupea harengus, in relation to density of copepod nauplii

    DEFF Research Database (Denmark)

    Kiørboe, Thomas; Munk, Peter

    1986-01-01

    Feeding and growth rates of 1–3 wk old herring larvae from four different stocks were compared in laboratory experiments (8°C). For most of the larval groups, feeding rate was saturated at nauplii (Acartia tonsa, nauplii stages 3–5) densities over 301−1 (5 μg d.w. 1−1). Specific growth rate incre...

  7. Bone mineral density in children and adolescents: relation to puberty, calcium intake, and physical activity

    NARCIS (Netherlands)

    A.M. Boot (Annemieke); H.A.P. Pols (Huib); E.P. Krenning (Eric); S.M.P.F. de Muinck Keizer-Schrama (Sabine); M.A.J. de Ridder (Maria)

    1997-01-01

    textabstractThe association of height, weight, pubertal stage, calcium intake, and physical activity with bone mineral density (BMD) was evaluated in 500 children and adolescents (205 boys and 295 girls), aged 4-20 yr. The BMD (grams per cm2) of lumbar spine and total

  8. Mapping brucellosis increases relative to elk density using hierarchical Bayesian models

    Science.gov (United States)

    Cross, Paul C.; Heisey, Dennis M.; Scurlock, Brandon M.; Edwards, William H.; Brennan, Angela; Ebinger, Michael R.

    2010-01-01

    The relationship between host density and parasite transmission is central to the effectiveness of many disease management strategies. Few studies, however, have empirically estimated this relationship particularly in large mammals. We applied hierarchical Bayesian methods to a 19-year dataset of over 6400 brucellosis tests of adult female elk (Cervus elaphus) in northwestern Wyoming. Management captures that occurred from January to March were over two times more likely to be seropositive than hunted elk that were killed in September to December, while accounting for site and year effects. Areas with supplemental feeding grounds for elk had higher seroprevalence in 1991 than other regions, but by 2009 many areas distant from the feeding grounds were of comparable seroprevalence. The increases in brucellosis seroprevalence were correlated with elk densities at the elk management unit, or hunt area, scale (mean 2070 km2; range = [95–10237]). The data, however, could not differentiate among linear and non-linear effects of host density. Therefore, control efforts that focus on reducing elk densities at a broad spatial scale were only weakly supported. Additional research on how a few, large groups within a region may be driving disease dynamics is needed for more targeted and effective management interventions. Brucellosis appears to be expanding its range into new regions and elk populations, which is likely to further complicate the United States brucellosis eradication program. This study is an example of how the dynamics of host populations can affect their ability to serve as disease reservoirs.

  9. Mapping brucellosis increases relative to elk density using hierarchical Bayesian models.

    Directory of Open Access Journals (Sweden)

    Paul C Cross

    Full Text Available The relationship between host density and parasite transmission is central to the effectiveness of many disease management strategies. Few studies, however, have empirically estimated this relationship particularly in large mammals. We applied hierarchical Bayesian methods to a 19-year dataset of over 6400 brucellosis tests of adult female elk (Cervus elaphus in northwestern Wyoming. Management captures that occurred from January to March were over two times more likely to be seropositive than hunted elk that were killed in September to December, while accounting for site and year effects. Areas with supplemental feeding grounds for elk had higher seroprevalence in 1991 than other regions, but by 2009 many areas distant from the feeding grounds were of comparable seroprevalence. The increases in brucellosis seroprevalence were correlated with elk densities at the elk management unit, or hunt area, scale (mean 2070 km(2; range = [95-10237]. The data, however, could not differentiate among linear and non-linear effects of host density. Therefore, control efforts that focus on reducing elk densities at a broad spatial scale were only weakly supported. Additional research on how a few, large groups within a region may be driving disease dynamics is needed for more targeted and effective management interventions. Brucellosis appears to be expanding its range into new regions and elk populations, which is likely to further complicate the United States brucellosis eradication program. This study is an example of how the dynamics of host populations can affect their ability to serve as disease reservoirs.

  10. Effects of stocking density on lipid deposition and expression of lipid-related genes in Amur sturgeon (Acipenser schrenckii).

    Science.gov (United States)

    Ren, Yuanyuan; Wen, Haishen; Li, Yun; Li, Jifang; He, Feng; Ni, Meng

    2017-12-01

    To investigate the correlation between lipid deposition variation and stocking density in Amur sturgeon (Acipenser schrenckii) and the possible physiological mechanism, fish were conducted in different stocking densities (LSD 5.5 kg/m 3 , MSD 8.0 kg/m 3 , and HSD 11.0 kg/m 3 ) for 70 days and then the growth index, lipid content, lipase activities, and the mRNA expressions of lipid-related genes were examined. Results showed that fish subjected to higher stocking density presented lower final body weights (FBW), specific growth ratio (SGR), and gonad adipose tissue index (GAI) (P density lipoprotein cholesterol (HDL-C) decreased significantly with increasing stocking density, while no significant change was observed for low-density lipoprotein cholesterol (LDL-C). Furthermore, the cDNAs encoding lipoprotein lipase (LPL) and hepatic lipase (HL) were isolated in Amur sturgeon, respectively. The full-length LPL cDNA was composed of 1757 bp with an open reading frame of 501 amino acids, while the complete nucleotide sequences of HL covered 1747 bp encoding 499 amino acids. In the liver, the activities and mRNA levels of LPL were markedly lower in HSD group, which were consistent with the variation tendency of HL. Fish reared in HSD group also presented lower levels of activities and mRNA expression of LPL in the muscle and gonad. Moreover, the expressions of peroxisome proliferator-activated receptor α (PPARα) in both the liver and skeletal muscle were significantly upregulated in HSD group. Overall, the results indicated that high stocking density negatively affects growth performance and lipid deposition of Amur sturgeon to a certain extent. The downregulation of LPL and HL and the upregulation of PPARα may be responsible for the lower lipid distribution of Amur sturgeon in higher stocking density.

  11. Copepod swimming behavior, respiration, and expression of stress-related genes in response to high stocking densities

    DEFF Research Database (Denmark)

    Nilsson, Birgitte; Jakobsen, Hans H.; Stief, Peter

    2017-01-01

    ,000 ind. L−1. Three biological/physiological end-points were studied: swimming behavior, respiration rate and expression level of stress-related genes. None of the elevated densities caused any significant change in swimming behavior, respiration rate or gene expression level. This study suggests...

  12. THE PHYSICAL ORIGINS OF THE MORPHOLOGY-DENSITY RELATION: EVIDENCE FOR GAS STRIPPING FROM THE SLOAN DIGITAL SKY SURVEY

    International Nuclear Information System (INIS)

    Van der Wel, Arjen; Bell, Eric F.; Skibba, Ramin A.; Rix, Hans-Walter; Holden, Bradford P.

    2010-01-01

    We provide a physical interpretation and explanation of the morphology-density relation for galaxies, drawing on stellar masses, star formation rates, axis ratios, and group halo masses from the Sloan Digital Sky Survey. We first re-cast the classical morphology-density relation in more quantitative terms, using low star formation rate (quiescence) as a proxy for early-type morphology and dark matter halo mass from a group catalog as a proxy for environmental density: for galaxies of a given stellar mass the quiescent fraction is found to increase with increasing dark matter halo mass. Our novel result is that-at a given stellar mass-quiescent galaxies are significantly flatter in dense environments, implying a higher fraction of disk galaxies. Supposing that the denser environments differ simply by a higher incidence of quiescent disk galaxies that are structurally similar to star-forming disk galaxies of similar mass, explains simultaneously and quantitatively these quiescence-environment and shape-environment relations. Our findings add considerable weight to the slow removal of gas as the main physical driver of the morphology-density relation, at the expense of other explanations.

  13. Triton-3He relative and differential flows as probes of the nuclear symmetry energy at supra-saturation densities

    International Nuclear Information System (INIS)

    Yong Gaochan; Li Baoan; Chen Liewen; Zhang Xunchao

    2009-01-01

    Using a transport model coupled with a phase-space coalescence afterburner, we study the triton- 3 He (t- 3 He) ratio with both relative and differential transverse flows in semicentral 132 Sn+ 124 Sn reactions at a beam energy of 400 MeV/nucleon. The neutron-proton ratios with relative and differential flows are also discussed as a reference. We find that similar to the neutron-proton pairs, the t- 3 He pairs also carry interesting information regarding the density dependence of the nuclear symmetry energy. Moreover, the nuclear symmetry energy affects more strongly the t- 3 He relative and differential flows than the π - /π + ratio in the same reaction. The t- 3 He relative flow can be used as a particularly powerful probe of the high-density behavior of the nuclear symmetry energy.

  14. Exact correlated kinetic energy related to the electron density for two-electron model atoms with harmonic confinement

    International Nuclear Information System (INIS)

    March, Norman H.; Akbari, Ali; Rubio, Angel

    2007-01-01

    For arbitrary interparticle interaction u(r 12 ), the model two-electron atom in the title is shown to be such that the ground-state electron density ρ(r) is determined uniquely by the correlated kinetic energy density t R (r) of the relative motion. Explicit results for t R (r) are presented for the Hookean atom with force constant k=1/4, and also for u(r 12 )=(λ)/(r 12 2 ) . Possible relevance of the Hookean atom treatment to the ground state of the helium atom itself is briefly discussed

  15. Effects of the instability enhanced friction on relative ion densities in a two-ion species low-temperature plasma

    Science.gov (United States)

    Vukovic, Mirko

    2011-10-01

    The instability enhanced friction theory of Baalrud & Hegna (Phys. Plasmas 18, 023505 (2011)) predicts that for comparable ion densities the ions nearly reach a common velocity near the sheath edge in a low temperature plasma. The theory was experimentally confirmed by Yip, Hershkowitz, & Severn (Phys. Rev. Letters 104, 225003 (2010)). We will explore the effects of the theory on relative ion densities in a numerical simulation of an Ar/Xe plasma. Results for a 0D plasma model (Lieberman, Lichtenberg, Principles of Plasma Discharges and Materials Processing, 2005) will be presented.

  16. On the relation between the statistical γ-decay and the level density in 162Dy

    International Nuclear Information System (INIS)

    Henden, L.; Bergholt, L.; Guttormsen, M.; Rekstad, J.; Tveter, T.S.

    1994-12-01

    The level density of low-spin states (0-10ℎ) in 162 Dy has been determined from the ground state up to approximately 6 MeV of excitation energy. Levels in the excitation region up to 8 MeV were populated by means of the 163 Dy( 3 He, α) reaction, and the first-generation γ-rays in the decay of these states has been isolated. The energy distribution of the first-generation γ-rays provides a new source of information about the nuclear level density over a wide energy region. A broad peak is observed in the first-generation spectra, and the authors suggest an interpretation in terms of enhanced M1 transitions between different high-j Nilsson orbitals. 30 refs., 9 figs., 2 tabs

  17. Problems related to the determination of mass densities of evaporated reference deposits

    Science.gov (United States)

    Tagziria, H.; Pauwels, J.; Verdonk, J.; Van Gestel, J.; Eykens, R.; Gilliam, D. M.; Scott, R. D.; Byrne, J.; Dawber, P.

    1991-05-01

    The accurate characterization of the surface density (nuclei/cm 2) of thin isotopic deposits is of highest importance in certain experiments. If accuracies better than ± 0.5% are to be quoted, careful consideration of seemingly minor effects is necessary, as these effects may generate serious errors. The radial surface density distribution in the central region of the target disks, the thickness profile at the edges, and the evaluation of effective deposit diameters are discussed for the case of measurements and observations made during the preparation and characterization of 6LiF and 10B reference deposits, which were employed in a recent determination of the free neutron lifetime. Theoretical calculations are in excellent agreement with the experimental results.

  18. Problems related to the determination of mass densities of evaporated reference deposits

    International Nuclear Information System (INIS)

    Tagziria, H.; Pauwels, J.; Verdonk, J.; Gestel, J. van; Eykens, R.; Gilliam, D.M.; Scott, R.D.; Byrne, J.; Dawber, P.

    1991-01-01

    The accurate characterization of the surface density (nuclei/cm 2 ) of thin isotopic deposits is of highest importance in certain experiments. If accuracies better than ±0.5% are to be quoted, careful consideration of seemingly minor effects is necessary, as these effects may generate serious errors. The radial surface density distribution in the central region of the target disks, the thickness profile at the edges, and the evaluation of effective deposit diameters are discussed for the case of measurements and observations made during the preparation and characterization of 6 LiF and 10 B reference deposits, which were employed in a recent determination of the free neutron lifetime. Theoretical calculations are in excellent agreement with the experimental results. (orig.)

  19. Problems related to the determination of mass densities of evaporated reference deposits

    Energy Technology Data Exchange (ETDEWEB)

    Tagziria, H.; Pauwels, J.; Verdonk, J.; Gestel, J. van; Eykens, R. (Commission of the European Communities, Joint Research Centre, Central Bureau for Nuclear Measurements, Geel (Belgium)); Gilliam, D.M. (National Inst. of Standards and Tech., Gaithersburg, MD (USA)); Scott, R.D. (Scottish Universities Research and Reactor Centre, Glasgow (UK)); Byrne, J.; Dawber, P. (School of Mathematical and Physical Sciences, Univ. of Sussex, Brighton (UK))

    1991-05-15

    The accurate characterization of the surface density (nuclei/cm{sup 2}) of thin isotopic deposits is of highest importance in certain experiments. If accuracies better than {+-}0.5% are to be quoted, careful consideration of seemingly minor effects is necessary, as these effects may generate serious errors. The radial surface density distribution in the central region of the target disks, the thickness profile at the edges, and the evaluation of effective deposit diameters are discussed for the case of measurements and observations made during the preparation and characterization of {sup 6}LiF and {sup 10}B reference deposits, which were employed in a recent determination of the free neutron lifetime. Theoretical calculations are in excellent agreement with the experimental results. (orig.).

  20. Effect of areal power density and relative humidity on corrosion resistant container performance

    International Nuclear Information System (INIS)

    Gansemer, J.D.

    1994-10-01

    The impact of the rewetting process on the performance of waste containers at the Yucca Mountain repository is analyzed. This paper explores the impact of the temperature-humidity relationships on pitting corrosion failure of stainless steel containers for different areal power densities (APDs)in the repository. It compares the likely performance of containers in a repository with a low APD, 55 Kw/acre, and a high APD, 110 kW/acre

  1. Predation on simulated duck nests in relation to nest density and landscape structure

    Czech Academy of Sciences Publication Activity Database

    Padyšáková, E.; Šálek, Martin; Poledník, L.; Sedláček, František; Albrecht, Tomáš

    2010-01-01

    Roč. 37, č. 7 (2010), s. 597-603 ISSN 1035-3712 R&D Projects: GA MŠk LC06073 Institutional research plan: CEZ:AV0Z60870520; CEZ:AV0Z60930519 Keywords : density-dependent predation * littoral patch * landscape type * nest predators * nest success * simulated nests Subject RIV: EG - Zoology Impact factor: 1.205, year: 2010

  2. Assessment of lesser prairie-chicken lek density relative to landscape characteristics in Texas

    Energy Technology Data Exchange (ETDEWEB)

    Timmer, Jennifer; Butler, Matthew; Ballard, Warren; Boal, Clint; Whitlaw, Heather

    2012-08-31

    My 2.5-yr Master's project accomplished the objectives of estimating lesser prairie-chicken (LPC) lek density and abundance in the Texas occupied range and modeling anthropogenic and landscape features associated with lek density by flying helicopter lek surveys for 2 field seasons and employing a line-transect distance sampling method. This project was important for several reasons. Firstly, wildlife managers and biologists have traditionally monitored LPC populations with road-based surveys that may result in biased estimates and do not provide access to privately-owned or remote property. From my aerial surveys and distance sampling, I was able to provide accurate density and abundance estimates, as well as new leks and I detected LPCs outside the occupied range. Secondly, recent research has indicated that energy development has the potential to impact LPCs through avoidance of tall structures, increased mortality from raptors perching on transmission lines, disturbance to nesting hens, and habitat loss/fragmentation. Given the potential wind energy development in the Texas Panhandle, spatial models of current anthropogenic and vegetative features (such as transmission lines, roads, and percent native grassland) influencing lek density were needed. This information provided wildlife managers and wind energy developers in Texas with guidelines for how change in landscape features could impact LPCs. Lastly, LPC populations have faced range-wide declines over the last century and they are currently listed as a candidate species under the Endangered Species Act. I was able to provide timely information on LPC populations in Texas that will be used during the listing process.

  3. Modelling Age- and Density-Related Gas Exchange of Picea abies Canopies in the Fichtelgebirge, Germany

    OpenAIRE

    Falge, Eva; Tennhunen, John D.; Ryel, Ronald J.; Alsheimer, Martina; Köstner, Barbara

    2000-01-01

    International audience; Differences in canopy exchange of water and carbon dioxide that occur due to changes in tree structure and density in montane Norway spruce stands of Central Germany were analyzed with a three dimensional microclimate and gas exchange model STANDFLUX. The model was used to calculate forest radiation absorption, the net photosynthesis and transpiration of single trees, and gas exchange of tree canopies. Model parameterizations were derived for six stands of Picea abies ...

  4. The role of forest stand density in controlling soil erosion: implications to sediment-related disasters in Japan.

    Science.gov (United States)

    Razafindrabe, Bam H N; He, Bin; Inoue, Shoji; Ezaki, Tsugio; Shaw, Rajib

    2010-01-01

    The role of forest stand density in controlling soil erosion was investigated in Ehime Prefecture, Japan. The main objective was to compare soil erosion under different forest conditions including forest type, species composition, and stand density as influenced by thinning operations. Relative yield index (Ry) was used as an indicator of stand density to reflect the degree of management operations in the watershed. Eleven treatments were established based on the above forest conditions. Soil loss was collected in each of the 11 treatments after each rainfall event for a period of 1 year. The paper presents summary data on soil loss as affected by forest conditions and rainfall patterns. Findings showed that an appropriate forest management operation, which can be insured by stand density control, is needed to reduce soil loss. The present study plays an important role in clarifying technical processes related to soil erosion, while it helps linking these elements to current Japanese forestry issues and bringing new inputs to reducing sediment-related disasters in Japan.

  5. Sampling Error in Relation to Cyst Nematode Population Density Estimation in Small Field Plots.

    Science.gov (United States)

    Župunski, Vesna; Jevtić, Radivoje; Jokić, Vesna Spasić; Župunski, Ljubica; Lalošević, Mirjana; Ćirić, Mihajlo; Ćurčić, Živko

    2017-06-01

    Cyst nematodes are serious plant-parasitic pests which could cause severe yield losses and extensive damage. Since there is still very little information about error of population density estimation in small field plots, this study contributes to the broad issue of population density assessment. It was shown that there was no significant difference between cyst counts of five or seven bulk samples taken per each 1-m 2 plot, if average cyst count per examined plot exceeds 75 cysts per 100 g of soil. Goodness of fit of data to probability distribution tested with χ 2 test confirmed a negative binomial distribution of cyst counts for 21 out of 23 plots. The recommended measure of sampling precision of 17% expressed through coefficient of variation ( cv ) was achieved if the plots of 1 m 2 contaminated with more than 90 cysts per 100 g of soil were sampled with 10-core bulk samples taken in five repetitions. If plots were contaminated with less than 75 cysts per 100 g of soil, 10-core bulk samples taken in seven repetitions gave cv higher than 23%. This study indicates that more attention should be paid on estimation of sampling error in experimental field plots to ensure more reliable estimation of population density of cyst nematodes.

  6. Impact factor of relationships between CT value and relative electron density for treatment planning system

    International Nuclear Information System (INIS)

    Feng Guosheng; Liang Yuan; Wu Danling; Hao Yanrong; Lu Heming; Chen Jiaxin; Liao Chaolong; Mo Ying; Huang Yihang

    2012-01-01

    Objective: To study the CT values of certain phantoms scanned by various CT scanners with dissimilar parameters. Methods: The CT values of tissue equivalent inserts was measured in the TM164 and CIRS-062 phantom scanned by TOSHIBA AQUILION TM , SIEMENS SOMATOM TM SENSATION TM 64 and SIEMENS SOMATOM TM SENSATION TM OPEN with different voltages,currents and slice thicknesses and then the corresponding CT-to-density curves was compared. Results: There are no significant differences of CT values with various currents and slice thicknesses and also for low atom number materials scanned by different scanners with various tube voltages. The CT values of high atom number materials have obvious differences scanned with tube voltage,the maximum is about 400 HU. There are also significant differences between CT-density curves of two phantoms in the range from soft tissues to dense bone, the maximum is up to 500 HU. Conclusions: CT-density curves were highly affected by materials of phantoms, scanners and tube voltages. It is necessary to measure the curve with a comfortable phantom and certain scanner to assure the accuracy for dose calculation for treatment planning system. (authors)

  7. Augmented potential, energy densities, and virial relations in the weak- and strong-interaction limits of DFT

    Science.gov (United States)

    Vuckovic, Stefan; Levy, Mel; Gori-Giorgi, Paola

    2017-12-01

    The augmented potential introduced by Levy and Zahariev [Phys. Rev. Lett. 113, 113002 (2014)] is shifted with respect to the standard exchange-correlation potential of the Kohn-Sham density functional theory by a density-dependent constant that makes the total energy become equal to the sum of the occupied orbital energies. In this work, we analyze several features of this approach, focusing on the limit of infinite coupling strength and studying the shift and the corresponding energy density at different correlation regimes. We present and discuss coordinate scaling properties of the augmented potential, study its connection to the response potential, and use the shift to analyze the classical jellium and uniform gas models. We also study other definitions of the energy densities in relation to the functional construction by local interpolations along the adiabatic connection. Our findings indicate that the energy density that is defined in terms of the electrostatic potential of the exchange-correlation hole is particularly well suited for this purpose.

  8. Seasonal Variation in Group Size Is Related to Seasonal Variation in Neuropeptide Receptor Density.

    Science.gov (United States)

    Wilson, Leah C; Goodson, James L; Kingsbury, Marcy A

    2016-01-01

    In many species, seasonal variation in grouping behavior is widespread, with shifts towards territoriality in the breeding season and grouping in the winter. Compared to the hormonal and neural mechanisms of seasonal territorial aggression, the mechanisms that promote seasonal grouping have received little attention. We collected brains in spring and winter from wild-caught males of two species of emberizid sparrows that seasonally flock (the field sparrow, Spizella pusilla, and the dark-eyed junco, Junco hyemalis) and two species that do not seasonally flock (the song sparrow, Melospiza melodia, and the eastern towhee, Pipilo erythrophthalmus). We used receptor autoradiography to quantify seasonal plasticity in available binding sites for three neuropeptides known to influence social behavior. We examined binding sites for 125I-vasoactive intestinal polypeptide (VIP), 125I-sauvagine (SG, a ligand for corticotropin-releasing hormone receptors) and 125I-ornithine vasotocin analog (OVTA, a ligand for the VT3 nonapeptide). For all species and ligands, brain areas that exhibited a seasonal pattern in binding density were characterized by a winter increase. Compared to nonflocking species, seasonally flocking species showed different binding patterns in multiple brain areas. Furthermore, we found that winter flocking was associated with elevated winter 125I-VIP binding density in the medial amygdala, as well as 125I-VIP and 125I-OVTA binding density in the rostral arcopallium. While the functional significance of the avian rostral arcopallium is unclear, it may incorporate parts of the pallial amygdala. Our results point to this previously undescribed area as a likely hot spot of social modulation. © 2016 S. Karger AG, Basel.

  9. A surface structural model for ferrihydrite I: Sites related to primary charge, molar mass, and mass density

    Science.gov (United States)

    Hiemstra, Tjisse; Van Riemsdijk, Willem H.

    2009-08-01

    A multisite surface complexation (MUSIC) model for ferrihydrite (Fh) has been developed. The surface structure and composition of Fh nanoparticles are described in relation to ion binding and surface charge development. The site densities of the various reactive surface groups, the molar mass, the mass density, the specific surface area, and the particle size are quantified. As derived theoretically, molecular mass and mass density of nanoparticles will depend on the types of surface groups and the corresponding site densities and will vary with particle size and surface area because of a relatively large contribution of the surface groups in comparison to the mineral core of nanoparticles. The nano-sized (˜2.6 nm) particles of freshly prepared 2-line Fh as a whole have an increased molar mass of M ˜ 101 ± 2 g/mol Fe, a reduced mass density of ˜3.5 ± 0.1 g/cm 3, both relatively to the mineral core. The specific surface area is ˜650 m 2/g. Six-line Fh (5-6 nm) has a molar mass of M ˜ 94 ± 2 g/mol, a mass density of ˜3.9 ± 0.1 g/cm 3, and a surface area of ˜280 ± 30 m 2/g. Data analysis shows that the mineral core of Fh has an average chemical composition very close to FeOOH with M ˜ 89 g/mol. The mineral core has a mass density around ˜4.15 ± 0.1 g/cm 3, which is between that of feroxyhyte, goethite, and lepidocrocite. These results can be used to constrain structural models for Fh. Singly-coordinated surface groups dominate the surface of ferrihydrite (˜6.0 ± 0.5 nm -2). These groups can be present in two structural configurations. In pairs, the groups either form the edge of a single Fe-octahedron (˜2.5 nm -2) or are present at a single corner (˜3.5 nm -2) of two adjacent Fe octahedra. These configurations can form bidentate surface complexes by edge- and double-corner sharing, respectively, and may therefore respond differently to the binding of ions such as uranyl, carbonate, arsenite, phosphate, and others. The relatively low PZC of

  10. Bulk density, cone index and water content relations for some Ghanian soils

    International Nuclear Information System (INIS)

    Agodzo, S.K.; Adama, I.

    2004-01-01

    Correlations were established between water content θ, bulk density ρ and cone index Δ for 4 Ghanaian soils, namely, Kumasi, Akroso, Nta and Offin series. The relationship between Δ and θ is in the form Δ = a θ 2 + b θ + c, where the correlation coefficients r 2 for the various soils were found to be very high. Similarly, Δ - ρ relationships were linear but the correlations got weaker with increasing sand content of the soil, as expected. Soil sample sizes and compaction procedures did not conform to standard procedures, yet the results did not deviate from what pertains when standard procedures are used. (author)

  11. [Analysis of elderly outpatients in relation to nutritional status, sarcopenia, renal function, and bone density].

    Science.gov (United States)

    Salmaso, Franciany Viana; Vigário, Patrícia dos Santos; Mendonça, Laura Maria Carvalho de; Madeira, Miguel; Vieira Netto, Leonardo; Guimarães, Marcela Rodrigues Moreira; Farias, Maria Lucia Fleiuss de

    2014-04-01

    To evaluate relationships between nutritional status, sarcopenia and osteoporosis in older women. We studied 44 women, 67-94 years, by mini-nutritional assessment (MAN), glomerular filtration corr. 1.73 m(2), body mass index (BMI), arm circumference and calf (CP and CB), bone mineral density and body composition, DXA (fat mass MG; lean MM). We gauge sarcopenia: IMM MM = MSS + MIS/height(2). We used the Pearson correlation coefficient, p nutritional status and body composition; and major influences on BMD were nutritional status and fat mass.

  12. Relative effects of chromium and niobium on microstructure and mechanical properties as a function of oxygen content in TiAl alloys

    International Nuclear Information System (INIS)

    Lamirand, M.; Bonnentien, J.-L.; Ferriere, G.; Guerin, S.; Chevalier, J.-P.

    2007-01-01

    The effects of 2 at.% chromium and niobium on microstructure and mechanical properties of Ti-48Al-x(Cr, Nb) have been investigated for alloys with different oxygen content, ranging from ultra-high purity to doped alloys. Chromium and niobium additions have significant effects for the high purity alloys, whereas for alloys containing oxygen, no significant modification is observed due to the strong stabilizing effect of oxygen on the lamellar microstructure

  13. Do galaxy global relationships emerge from local ones? The SDSS IV MaNGA surface mass density-metallicity relation

    Science.gov (United States)

    Barrera-Ballesteros, Jorge K.; Heckman, Timothy M.; Zhu, Guangtun B.; Zakamska, Nadia L.; Sánchez, Sebastian F.; Law, David; Wake, David; Green, Jenny E.; Bizyaev, Dmitry; Oravetz, Daniel; Simmons, Audrey; Malanushenko, Elena; Pan, Kaike; Roman Lopes, Alexandre; Lane, Richard R.

    2016-12-01

    We present the stellar surface mass density versus gas metallicity (Σ*-Z) relation for more than 500 000 spatially resolved star-forming resolution elements (spaxels) from a sample of 653 disc galaxies included in the SDSS IV MaNGA survey. We find a tight relation between these local properties, with higher metallicities as the surface density increases. This relation extends over three orders of magnitude in the surface mass density and a factor of 4 in metallicity. We show that this local relationship can simultaneously reproduce two well-known properties of disc galaxies: their global mass-metallicity relationship and their radial metallicity gradients. We also find that the Σ*-Z relation is largely independent of the galaxy's total stellar mass and specific star formation rate (sSFR), except at low stellar mass and high sSFR. These results suggest that in the present-day universe local properties play a key role in determining the gas-phase metallicity in typical disc galaxies.

  14. Topographic and sex-related differences in sleep spindles in major depressive disorder: a high-density EEG investigation.

    Science.gov (United States)

    Plante, D T; Goldstein, M R; Landsness, E C; Peterson, M J; Riedner, B A; Ferrarelli, F; Wanger, T; Guokas, J J; Tononi, G; Benca, R M

    2013-03-20

    Sleep spindles are believed to mediate several sleep-related functions including maintaining disconnection from the external environment during sleep, cortical development, and sleep-dependent memory consolidation. Prior studies that have examined sleep spindles in major depressive disorder (MDD) have not demonstrated consistent differences relative to control subjects, which may be due to sex-related variation and limited spatial resolution of spindle detection. Thus, this study sought to characterize sleep spindles in MDD using high-density electroencephalography (hdEEG) to examine the topography of sleep spindles across the cortex in MDD, as well as sex-related variation in spindle topography in the disorder. All-night hdEEG recordings were collected in 30 unipolar MDD participants (19 women) and 30 age and sex-matched controls. Topography of sleep spindle density, amplitude, duration, and integrated spindle activity (ISA) were assessed to determine group differences. Spindle parameters were compared between MDD and controls, including analysis stratified by sex. As a group, MDD subjects demonstrated significant increases in frontal and parietal spindle density and ISA compared to controls. When stratified by sex, MDD women demonstrated increases in frontal and parietal spindle density, amplitude, duration, and ISA; whereas MDD men demonstrated either no differences or decreases in spindle parameters. Given the number of male subjects, this study may be underpowered to detect differences in spindle parameters in male MDD participants. This study demonstrates topographic and sex-related differences in sleep spindles in MDD. Further research is warranted to investigate the role of sleep spindles and sex in the pathophysiology of MDD. Copyright © 2012 Elsevier B.V. All rights reserved.

  15. Flocculation of Clay Colloids Induced by Model Polyelectrolytes: Effects of Relative Charge Density and Size.

    Science.gov (United States)

    Sakhawoth, Yasine; Michot, Laurent J; Levitz, Pierre; Malikova, Natalie

    2017-10-06

    Flocculation and its tuning are of utmost importance in the optimization of several industrial protocols in areas such as purification of waste water and civil engineering. Herein, we studied the polyelectrolyte-induced flocculation of clay colloids on a model system consisting of purified clay colloids of well-defined size fractions and ionene polyelectrolytes presenting regular and tunable chain charge density. To characterize ionene-induced clay flocculation, we turned to the combination of light absorbance (turbidity) and ζ-potential measurements, as well as adsorption isotherms. Our model system allowed us to identify the exact ratio of positive and negative charges in clay-ionene mixtures, the (c+/c-) ratio. For all samples studied, the onset of efficient flocculation occurred consistently at c+/c- ratios significantly below 1, which indicated the formation of highly ionene-deficient aggregates. At the same time, the ζ-potential measurements indicated an apparent zero charge on such aggregates. Thus, the ζ-potential values could not provide the stoichiometry inside the clay-ionene aggregates. The early onset of flocculation in clay-ionene mixtures is reminiscent of the behavior of multivalent salts and contrasts that of monovalent salts, for which a large excess amount of ions is necessary to achieve flocculation. Clear differences in the flocculation behavior are visible as a function of the ionene charge density, which governs the conformation of the ionene chains on the clay surface. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Abundance of plankton population densities in relation to bottom soil textural types in aquaculture ponds

    Directory of Open Access Journals (Sweden)

    F. Siddika

    2012-06-01

    Full Text Available Plankton is an important food item of fishes and indicator for the productivity of a water body. The present study was conducted to evaluate the effects of bottom soil textural conditions on abundance of plankton in aquaculture pond. The experiment was carried out using three treatments, i.e., ponds bottom with sandy loam (T1, with loam (T2 and with clay loam (T3. The ranges of water quality parameters analyzed were suitable for the growth of plankton during the experimental period. Similarly, chemical properties of soil were also within suitable ranges and every parameter showed higher ranges in T2. A total 20 genera of phytoplankton were recorded belonged to Chlorophyceae (7, Cyanophyceae (5, Bacillariophyceae (5, Euglenophyceae (2 and Dinophyceae (1. On the other hand, total 13 genera of zooplankton were recorded belonged to Crustacea (7 and Rotifera (6. The highest ranges of phytoplankton and zooplankton densities were found in T2 where low to medium-type bloom was observed during the study period. Consequently, the mean abundance of plankton (phytoplankton and zooplankton density was significantly highest in T2. The highest abundance of plankton in the T2 indicated that pond bottom with loamy soil is suitable for the growth and production of plankton in aquaculture ponds.

  17. Plasticity and density-moisture-resistance relations of soils amended with fly ash

    Energy Technology Data Exchange (ETDEWEB)

    Mapfuno, E.; Chanasyk, D.S. [University of Alberta, Edmonton, AB (Canada). Dept. of Renewable Resources

    1998-06-01

    The objective of this study was to investigate the impact of fly ash amendments on the plasticity, water retention and penetration resistance-density-moisture relationships of three soils of sandy loam, loam and clay loam textures in order to determine the potential compaction of these soil/fly ash mixtures if they were worked at different moisture ranges. For all three soils the addition of fly ash decreased the plasticity index, but slightly increased the Proctor maximum density. This implies that fly ash amendments reduce the range of moisture within which soils are most susceptible to compaction. However, for the sandy loam and loam textured soils amended with fly ash, cultivation must be avoided at moisture contents close to field capacity since maximum densification occurs at these moisture contents. In all three soils the addition of fly ash increased water retention, especially in the sandy loam. Fly ash amendments increased penetration resistance of the clay loam, but increased penetration resistance of the sandy loam.

  18. [Development of a software standardizing optical density with operation settings related to several limitations].

    Science.gov (United States)

    Tu, Xiao-Ming; Zhang, Zuo-Heng; Wan, Cheng; Zheng, Yu; Xu, Jin-Mei; Zhang, Yuan-Yuan; Luo, Jian-Ping; Wu, Hai-Wei

    2012-12-01

    To develop a software that can be used to standardize optical density to normalize the procedures and results of standardization in order to effectively solve several problems generated during standardization of in-direct ELISA results. The software was designed based on the I-STOD method with operation settings to solve the problems that one might encounter during the standardization. Matlab GUI was used as a tool for the development. The software was tested with the results of the detection of sera of persons from schistosomiasis japonica endemic areas. I-STOD V1.0 (WINDOWS XP/WIN 7, 0.5 GB) was successfully developed to standardize optical density. A serial of serum samples from schistosomiasis japonica endemic areas were used to examine the operational effects of I-STOD V1.0 software. The results indicated that the software successfully overcame several problems including reliability of standard curve, applicable scope of samples and determination of dilution for samples outside the scope, so that I-STOD was performed more conveniently and the results of standardization were more consistent. I-STOD V1.0 is a professional software based on I-STOD. It can be easily operated and can effectively standardize the testing results of in-direct ELISA.

  19. Volumetric breast density measurement: sensitivity analysis of a relative physics approach.

    Science.gov (United States)

    Lau, Susie; Ng, Kwan Hoong; Abdul Aziz, Yang Faridah

    2016-10-01

    To investigate the sensitivity and robustness of a volumetric breast density (VBD) measurement system to errors in the imaging physics parameters including compressed breast thickness (CBT), tube voltage (kVp), filter thickness, tube current-exposure time product (mAs), detector gain, detector offset and image noise. 3317 raw digital mammograms were processed with Volpara(®) (Matakina Technology Ltd, Wellington, New Zealand) to obtain fibroglandular tissue volume (FGV), breast volume (BV) and VBD. Errors in parameters including CBT, kVp, filter thickness and mAs were simulated by varying them in the Digital Imaging and Communications in Medicine (DICOM) tags of the images up to ±10% of the original values. Errors in detector gain and offset were simulated by varying them in the Volpara configuration file up to ±10% from their default values. For image noise, Gaussian noise was generated and introduced into the original images. Errors in filter thickness, mAs, detector gain and offset had limited effects on FGV, BV and VBD. Significant effects in VBD were observed when CBT, kVp, detector offset and image noise were varied (p applications such as tracking density change over time, it remains to be seen how accurate the measures need to be.

  20. A grey relational analytical approach to orange peel filler particulates for tapped density experiments of green composite reinforcements

    Directory of Open Access Journals (Sweden)

    Oluwaseyi Ayodele Ajibade

    2016-08-01

    Full Text Available Monitoring density changes during transportation of composite fillers is the principal reason for composite industries implementing the tapped density concept. Till date, very sparse literature information exists on tapped density optimisation for orange peel particles (OPPs. A unique application of grey relational analysis (GRA in the optimisation of tapped process parameters for OPPs is contributed in this paper. Experimental results on the principal process parameters indicate G1H1I2J3 as the best experimental run, which translates to 257.956 g and 78.076 cm3 as well as 254.939 g and 72.94 cm3 for masses and volumes of the 0.425 and 0.600 mm OPPs, respectively. In addition, Taguchi method was applied to arrive at an optimal parametric setting of G2H2I1J1 for comparative purposes which translate to 257.723 g and 75.031 cm3 for mass and volume of the 0.425 OPPs, as well as 254.952 g and 77.982 cm3 for the mass and volume of 0.600 mm OPPs. By comparison, the GRA values produced positive percentage improvement over other optimal values. The unique contribution of this paper are principally the (i application of GRA in a novel manner, incorporating harmonic mean in factor-level determination and computation of S/N responses; (ii development of new indices of tapped density; and (iii introduction of economic factors in tapped density computations, incorporating inflation and interest factors. The practical utility of the demonstrated approach lies in reducing the uncertainties about density measurements in the transportation of green fillers for use as composite reinforcements.

  1. Relation between size of contrast meter and radiographic density difference for radiographic test aluminium welds

    International Nuclear Information System (INIS)

    Senda, Tomio; Hirayama, Kazuo; Masaoka, Naotoshi; Fujita, Minoru.

    1977-01-01

    The influence of contrast meter with difference surface area (5.0 mm x 5.0 mm, 10.0 mm x 10.0 mm, 15.0 mm x 15.0 mm, 30.0 mm x 30.0 mm) and separated type on radiographic density difference (Δ D) were investigated for radiographic test of aluminum welds. It was found that the effect of scattered radiation on contrast meter represented highest at test specimen thickness of 20 mm, and Δ D was constant as the size was increased from 10.0 mm x 10.0 mm to 15.0 mm x 15.0 mm for aluminum contrast meter. For this reason, a proposal of the contrast meter with 10.0 mm x 10.0 mm (surface area) has made to replace (15.0 mm x 15 mm) at amendment of JIS Z 3105. (auth.)

  2. Relation of parity and homocysteine to bone mineral density of postmenopausal women.

    Science.gov (United States)

    Yilmaz, Necat; Kepkep, Necip; Ciçek, Hülya Kanbur; Celik, Ahmet; Meram, Iclal

    2006-01-01

    Osteoporosis is a major problem in contemporary society. However, there is not enough data on multiparity and osteoporosis from developing and/or undeveloped countries on a large scale. Selection of participants in this study was aimed at the detection of bone status in healthy (normal bone mineral density) postmenopausal (n = 46, 55.3 +/- 6.7 years) and osteoporotic postmenopausal women (n: 33) of similar age. Bone mineral density (BMD) was evaluated using dual energy X-ray absorptiometry. At the DEXA evaluation, 33 women had osteoporotic (T score below -2.5) and 46 had normal BMD values. The number of pregnancies was found to range from 3 to 12 (with an overall mean of 6.7 +/- 2.5), while 2.6 +/- 1.9 (range, 1-7) were miscarriages in all of the 33 postmenopausal osteoporotic women. Serum homocysteine (t-Hcy) and urinary deoxypyridinoline (DPD) levels were significantly higher in osteoporotic postmenopausal women (11.96 +/- 3.84 micromol/L, 15.4 +/- 7.0 nM/mM cr) than in non-osteoporotic postmenopausal women (10.93 +/- 3.6 micromol/L, 10.6 +/- 9.1 nM/mM cr), p pregnancies is unclear, and the relationship may only be by chance. In conclusion, the present study firstly suggests that the number of pregnancies has an effect on the t-Hcy levels. In addition, our study indicates that there is a significant negative correlation between the number of pregnancies and the lumbar spine BMD.

  3. Effects of C and Hf concentration on phase relations and microstructure of a wrought powder-metallurgy superalloy

    Science.gov (United States)

    Miner, R. V., Jr.

    1977-01-01

    NASA IIB-11, a candidate alloy for advanced temperature turbine engine disks, and four modifications with varying C and Hf concentrations were produced from prealloyed powders. Several notable effects of C and Hf concentration in the alloys were observed. Both the amount of the gamma-prime phase and its solvus temperature increased with decreasing C, but only the gamma-prime solvus was affected by Hf, increasing with increasing Hf. Hf also promoted a cellular gamma-prime precipitation. Hf was, however, about equally distributed between gamma-prime and gamma. Hf and C both affected the carbides formed. Increasing both promoted formation of an MC relative to that of an M6C.

  4. The Riemann problem for the relativistic full Euler system with generalized Chaplygin proper energy density-pressure relation

    Science.gov (United States)

    Shao, Zhiqiang

    2018-04-01

    The relativistic full Euler system with generalized Chaplygin proper energy density-pressure relation is studied. The Riemann problem is solved constructively. The delta shock wave arises in the Riemann solutions, provided that the initial data satisfy some certain conditions, although the system is strictly hyperbolic and the first and third characteristic fields are genuinely nonlinear, while the second one is linearly degenerate. There are five kinds of Riemann solutions, in which four only consist of a shock wave and a centered rarefaction wave or two shock waves or two centered rarefaction waves, and a contact discontinuity between the constant states (precisely speaking, the solutions consist in general of three waves), and the other involves delta shocks on which both the rest mass density and the proper energy density simultaneously contain the Dirac delta function. It is quite different from the previous ones on which only one state variable contains the Dirac delta function. The formation mechanism, generalized Rankine-Hugoniot relation and entropy condition are clarified for this type of delta shock wave. Under the generalized Rankine-Hugoniot relation and entropy condition, we establish the existence and uniqueness of solutions involving delta shocks for the Riemann problem.

  5. Study of optimal X-ray exposure conditions in consideration of bone mineral density. Relation between bone mineral density and image contrast

    International Nuclear Information System (INIS)

    Kondo, Yuji

    2003-01-01

    Bone mineral density (BMD) increases through infancy and adolescence, reaching a maximum at 20-30 years of age. Thereafter, BMD gradually decreases with age in both sexes. The image contrast of radiographs of bones varies with the change in BMD owing to the changes in the X-ray absorption of bone. The image contrast of bone generally is higher in the young adult than in the older adult. To examine the relation between BMD and image visibility, we carried out the following experiments. We measured the image contrast of radiographs of a lumbar vertebra phantom in which BMD was equivalent to the average BMD for each developmental period. We examined image visibility at various levels of imaging contrast using the Howlett chart. The results indicated that differences in BMD affect the image contrast of radiographs, and, consequently, image visibility. It was also found that image visibility in the young adult was higher than that in the older adult. The findings showed that, in digital radiography of young adults with high BMD, X-ray exposure can be decreased according the ratio of improvement in image visibility. (author)

  6. Histamine H3 receptor density is negatively correlated with neural activity related to working memory in humans.

    Science.gov (United States)

    Ito, Takehito; Kimura, Yasuyuki; Seki, Chie; Ichise, Masanori; Yokokawa, Keita; Kawamura, Kazunori; Takahashi, Hidehiko; Higuchi, Makoto; Zhang, Ming-Rong; Suhara, Tetsuya; Yamada, Makiko

    2018-06-14

    The histamine H 3 receptor is regarded as a drug target for cognitive impairments in psychiatric disorders. H 3 receptors are expressed in neocortical areas, including the prefrontal cortex, the key region of cognitive functions such as working memory. However, the role of prefrontal H 3 receptors in working memory has not yet been clarified. Therefore, using functional magnetic resonance imaging (fMRI) and positron emission tomography (PET) techniques, we aimed to investigate the association between the neural activity of working memory and the density of H 3 receptors in the prefrontal cortex. Ten healthy volunteers underwent both fMRI and PET scans. The N-back task was used to assess the neural activities related to working memory. H 3 receptor density was measured with the selective PET radioligand [ 11 C] TASP457. The neural activity of the right dorsolateral prefrontal cortex during the performance of the N-back task was negatively correlated with the density of H 3 receptors in this region. Higher neural activity of working memory was associated with lower H 3 receptor density in the right dorsolateral prefrontal cortex. This finding elucidates the role of H 3 receptors in working memory and indicates the potential of H 3 receptors as a therapeutic target for the cognitive impairments associated with neuropsychiatric disorders.

  7. Paternal epigenetic effects of population density on locust phase-related characteristics associated with heat-shock protein expression.

    Science.gov (United States)

    Chen, Bing; Li, Shaoqin; Ren, Qiang; Tong, Xiwen; Zhang, Xia; Kang, Le

    2015-02-01

    Many species exhibit transgenerational plasticity by which environmental cues experienced by either parent can be transmitted to their offspring, resulting in phenotypic variants in offspring to match ancestral environments. However, the manner by which paternal experiences affect offspring plasticity through epigenetic inheritance in animals generally remains unclear. In this study, we examined the transgenerational effects of population density on phase-related traits in the migratory locust Locusta migratoria. Using an experimental design that explicitly controls genetic background, we found that the effects of crowd or isolation rearing on phase plasticity could be inherited to the offspring. The isolation of gregarious locusts resulted in reduced weight in offspring eggs and altered morphometric traits in hatchlings, whereas crowding of solitarious locusts exhibited opposite effects. The consequences of density changes were transmitted by both maternal and paternal inheritance, although the expression of paternal effects was not as pronounced as that of maternal effects. Prominent expression of heat-shock proteins (Hsps), such as Hsp90, Hsp70 and Hsp20.6, could be triggered by density changes. Hsps were significantly upregulated upon crowding but downregulated upon isolation. The variation in parental Hsp expression was also transmitted to the offspring, in which the pattern of inheritance was consistent with that of phase characteristics. These results revealed a paternal effect on phase polyphenism and Hsp expression induced by population density, and defined a model system that could be used to study the paternal epigenetic inheritance of environmental changes. © 2015 John Wiley & Sons Ltd.

  8. Soil aggregation and slope stability related to soil density, root length, and mycorrhiza

    Science.gov (United States)

    Graf, Frank; Frei, Martin

    2013-04-01

    Eco-engineering measures combine the use of living plants and inert mechanical constructions to protect slopes against erosion and shallow mass movement. Whereas in geotechnical engineering several performance standards and guidelines for structural safety and serviceability of construction exist, there is a lack of comparable tools in the field of ecological restoration. Various indicators have been proposed, including the fractal dimension of soil particle size distribution, microbiological parameters, and soil aggregate stability. We present results of an soil aggregate stability investigation and compare them with literature data of the angle of internal friction ?' which is conventionally used in slope stability analysis and soil failure calculation. Aggregate stability tests were performed with samples of differently treated moraine, including soil at low (~15.5 kN/m³) and high (~19.0 kN/m³) dry unit weight, soil planted with Alnus incana (White Alder) as well as the combination of soil planted with alder and inoculated with the mycorrhizal fungus Melanogaster variegatus s.l. After a 20 weeks growth period in a greenhouse, a total of 100 samples was tested and evaluated. Positive correlations were found between the soil aggregate stability and the three variables dry unit weight, root length per soil volume, and degree of mycorrhization. Based on robust statistics it turned out that dry unit weight and mycorrhization degree were strongest correlated with soil aggregate stability. Compared to the non-inoculated control plants, mycorrhized White Alder produced significantly more roots and higher soil aggregate stability. Furthermore, the combined biological effect of plant roots and mycorrhizal mycelia on aggregate stability on soil with low density (~15.5 kN/m³) was comparable to the compaction effect of the pure soil from 15.5 to ~19.0 kN/m³. Literature data on the effect of vegetation on the angle of internal friction ?' of the same moraine showed

  9. Association of polymorphisms in low-density lipoprotein receptor- related protein 5 gene with bone mineral density in postmenopausal Chinese women

    Institute of Scientific and Technical Information of China (English)

    Zhen-lin ZHANG; Yue-juan QIN; Jin-wei HE; Qi-ren HUANG; Miao LI; Yun-qiu HU; Yu-juan LIU

    2005-01-01

    Aim: To investigate the possible association of Q89R, N740N and A1330V polymorphisms in low-density lipoprotein receptor-related protein 5 (LRP5) gene with bone mineral density (BMD) in postmenopausal Chinese women. Methods: Q89R,N740N and A1330V genotypes were determined by polymerase chain reactionrestriction fragment length polymorphism (PCR-RFLP) in 647 unrelated healthy postmenopausal Han Chinese women aged 43-76 years in Shanghai. BMD at lumbar spine 1-4 and the left proximal femur including the femoral neck, trochanter and Ward's triangle were measured by dual-energy X-ray absorptionmetry in all subjects. Results: The distribution of the Q89R, N740N and A1330V genotypes in this population was as follows: QQ 80.5%, QR 18.7%, and RR 0.8%; TT 66.9%,TC 31.1%, and CC 2.0%; AA 68.0%, AV 29.7%, and VV 2.3%. The frequencies of the Q89R, N740N and A1330V genotypes and alleles did not deviate from the HardyWeinberg equilibrium. We found that the Q89R and A1330V polymorphisms were in linkage disequilibrium in our population (x2= 13.50, P<0.01). Both before and after adjusting for age, years since menopause, height, and weight, the Q89R or N740N genotypes were significantly associated with BMD at the femoral neck (P<0.05).Subjects with the Q89R QQ genotype or the N740N TT genotype had a significantly higher BMD at the femoral neck, compared with those with the QR/RR or TC/CC genotypes, respectively. No significant association was found between A1330V polymorphism and BMD at any site. Conclusion: Our findings suggest that the LRP5 gene is a candidate for the genetic determination of BMD in postmenopausal Chinese women.

  10. On the de Vaucouleurs density-radius relation and the cellular intermediate large-scale structure of the universe

    International Nuclear Information System (INIS)

    Ruffini, R.

    1989-01-01

    In the present interpretation of the de Vaucouleurs mass density relation within the framework of universal fractal and cellular structure, attention is given to the relationship of such structure to the conventionally assumed cosmological conditions of three-dimensional homogeneity and isotropy. It is noted to be possible that the degree of regularity of the fractal structure will allow the definition, for distances smaller than the upper cutoff, of a Hubble ratio; this would be a function of the distance, however, and is clearly not directly related to a cosmological interpretation. 44 refs

  11. Cortico-cortical white matter motor pathway microstructure is related to psychomotor retardation in major depressive disorder.

    Directory of Open Access Journals (Sweden)

    Tobias Bracht

    Full Text Available Alterations of brain structure and function have been associated with psychomotor retardation in major depressive disorder (MDD. However, the association of motor behaviour and white matter integrity of motor pathways in MDD is unclear. The aim of the present study was to first investigate structural connectivity of white matter motor pathways in MDD. Second, we explore the relation of objectively measured motor activity and white matter integrity of motor pathways in MDD. Therefore, 21 patients with MDD and 21 healthy controls matched for age, gender, education and body mass index underwent diffusion tensor imaging and 24 hour actigraphy (measure of the activity level the same day. Applying a probabilistic fibre tracking approach we extracted connection pathways between the dorsolateral prefrontal cortex (dlPFC, the rostral anterior cingulate cortex (rACC, the pre-supplementary motor area (pre-SMA, the SMA-proper, the primary motor cortex (M1, the caudate nucleus, the putamen, the pallidum and the thalamus. Patients had lower activity levels and demonstrated increased mean diffusivity (MD in pathways linking left pre-SMA and SMA-proper, and right SMA-proper and M1. Exploratory analyses point to a positive association of activity level and mean-fractional anisotropy in the right rACC-pre-SMA connection in MDD. Only MDD patients with low activity levels had a negative linear association of activity level and mean-MD in the left dlPFC-pre-SMA connection. Our results point to structural alterations of cortico-cortical white matter motor pathways in MDD. Altered white matter organisation of rACC-pre-SMA and dlPFC-pre-SMA pathways may contribute to movement initiation in MDD.

  12. VEGF expression and microvascular density in relation to high-risk ...

    African Journals Online (AJOL)

    HPV)- related cancer mandates the search for new treatment modalities. Therapeutic targeting of tumor vasculature is a promising strategy. The aim was to study angiogenesis in cervical carcinoma in terms of VEGF expression and assessment ...

  13. Changes in plasma low-density lipoprotein (LDL)- and high-density lipoprotein cholesterol in hypo- and hyperthyroid patients are related to changes in free thyroxine, not to polymorphisms in LDL receptor or cholesterol ester transfer protein genes

    NARCIS (Netherlands)

    Diekman, M. J.; Anghelescu, N.; Endert, E.; Bakker, O.; Wiersinga, W. M.

    2000-01-01

    Thyroid function disorders lead to changes in lipoprotein metabolism. Both plasma low-density lipoprotein cholesterol (LDL-C) and high-density lipoprotein cholesterol (HDL-C) increase in hypothyroidism and decrease in hyperthyroidism. Changes in LDL-C relate to altered clearance of LDL particles

  14. Microstructural characterization of silicon added titanium aluminide

    International Nuclear Information System (INIS)

    Khan, A.N.

    2009-01-01

    Titanium aluminides intermetallic compounds have received great attention during the past decade, since they have the potential, in aircraft and automotive engines, to replace the high density Ni-base superalloys However, these intermetallics possess poor oxidation properties at high temperatures. Previous studies showed that protective alumina scale formation on gamma-TiAl can be obtained by small additions (around 2 at.%) of Ag. In the present study, a number of cast Ti-Al-Si alloys were investigated in relation to transient oxide formation in air at 1300 deg. C. After various oxidation times the oxide composition, microstructure and morphology were studied by combining a number of analysis techniques. The TiAl-Si alloys appear to form Al Ti and Si oxides. However, the formation of silicon oxide at the interface of base metal and scale slows down the oxidation rate significantly. (author)

  15. Microstructure-strength relations in a hardenable stainless steel with 16 pct Cr, 1.5 pct Mo, and 5 pct Ni

    Science.gov (United States)

    Grobner, P. J.; Blšs, V.

    1984-07-01

    Metallographic studies have been conducted on a 0.024 pct C-16 pct Cr-1.5 pct Mo-5 pct Ni stainless steel to study the phase reactions associated with heat treatments and investigate the strengthening mechanisms of the steel. In the normalized condition, air cooled from 1010 °C, the microstructure consists of 20 pct ferrite and 80 pct martensite. Tempering in a temperature range between 500 and 600 °C results in a gradual transformation of martensite to a fine mixture of ferrite and austenite. At higher tempering temperatures, between 600 and 800 °C, progressively larger quantities of austenite form and are converted during cooling to proportionally increasing amounts of fresh martensite. The amount of retained austenite in the microstructure is reduced to zero at 800 °C, and the microstructure contains 65 pct re-formed martensite and 35 pct total ferrite. Chromium rich M23C6 carbides precipitate in the single tempered microstructures. The principal strengthening is produced by the presence of martensite in the microstructure. Additional strengthening is provided by a second tempering treatment at 400 °C due to the precipitation of ultrafine (Cr, Mo) (C,N) particles in the ferrite.

  16. Relative Contribution of Matrix Structure, Patch Resources and Management to the Local Densities of Two Large Blue Butterfly Species.

    Science.gov (United States)

    Kajzer-Bonk, Joanna; Skórka, Piotr; Nowicki, Piotr; Bonk, Maciej; Król, Wiesław; Szpiłyk, Damian; Woyciechowski, Michal

    2016-01-01

    The type of matrix, the landscape surrounding habitat patches, may determine the distribution and function of local populations. However, the matrix is often heterogeneous, and its various components may differentially contribute to metapopulation processes at different spatial scales, a phenomenon that has rarely been investigated. The aim of this study was to estimate the relative importance of matrix composition and spatial scale, habitat quality, and management intensity on the occurrence and density of local populations of two endangered large blue butterflies: Phengaris teleius and P. nausithous. Presence and abundance data were assessed over two years, 2011-12, in 100 local patches within two heterogeneous regions (near Kraków and Tarnów, southern Poland). The matrix composition was analyzed at eight spatial scales. We observed high occupancy rates in both species, regions and years. With the exception of area and isolation, almost all of the matrix components contributed to Phengaris sp. densities. The different matrix components acted at different spatial scales (grassland cover within 4 and 3 km, field cover within 0.4 and 0.3 km and water cover within 4 km radii for P. teleius and P. nausithous, respectively) and provided the highest independent contribution to the butterfly densities. Additionally, the effects of a 0.4 km radius of forest cover and a food plant cover on P. teleius, and a 1 km radius of settlement cover and management intensity on P. nausithous densities were observed. Contrary to former studies we conclude that the matrix heterogeneity and spatial scale rather than general matrix type are of relevance for densities of butterflies. Conservation strategies for these umbrella species should concentrate on maintaining habitat quality and managing matrix composition at the most appropriate spatial scales.

  17. Relative Contribution of Matrix Structure, Patch Resources and Management to the Local Densities of Two Large Blue Butterfly Species

    Science.gov (United States)

    Skórka, Piotr; Nowicki, Piotr; Bonk, Maciej; Król, Wiesław; Szpiłyk, Damian; Woyciechowski, Michal

    2016-01-01

    The type of matrix, the landscape surrounding habitat patches, may determine the distribution and function of local populations. However, the matrix is often heterogeneous, and its various components may differentially contribute to metapopulation processes at different spatial scales, a phenomenon that has rarely been investigated. The aim of this study was to estimate the relative importance of matrix composition and spatial scale, habitat quality, and management intensity on the occurrence and density of local populations of two endangered large blue butterflies: Phengaris teleius and P. nausithous. Presence and abundance data were assessed over two years, 2011–12, in 100 local patches within two heterogeneous regions (near Kraków and Tarnów, southern Poland). The matrix composition was analyzed at eight spatial scales. We observed high occupancy rates in both species, regions and years. With the exception of area and isolation, almost all of the matrix components contributed to Phengaris sp. densities. The different matrix components acted at different spatial scales (grassland cover within 4 and 3 km, field cover within 0.4 and 0.3 km and water cover within 4 km radii for P. teleius and P. nausithous, respectively) and provided the highest independent contribution to the butterfly densities. Additionally, the effects of a 0.4 km radius of forest cover and a food plant cover on P. teleius, and a 1 km radius of settlement cover and management intensity on P. nausithous densities were observed. Contrary to former studies we conclude that the matrix heterogeneity and spatial scale rather than general matrix type are of relevance for densities of butterflies. Conservation strategies for these umbrella species should concentrate on maintaining habitat quality and managing matrix composition at the most appropriate spatial scales. PMID:28005942

  18. Obtaining source current density related to irregularly structured electromagnetic target field inside human body using hybrid inverse/FDTD method.

    Science.gov (United States)

    Han, Jijun; Yang, Deqiang; Sun, Houjun; Xin, Sherman Xuegang

    2017-01-01

    Inverse method is inherently suitable for calculating the distribution of source current density related with an irregularly structured electromagnetic target field. However, the present form of inverse method cannot calculate complex field-tissue interactions. A novel hybrid inverse/finite-difference time domain (FDTD) method that can calculate the complex field-tissue interactions for the inverse design of source current density related with an irregularly structured electromagnetic target field is proposed. A Huygens' equivalent surface is established as a bridge to combine the inverse and FDTD method. Distribution of the radiofrequency (RF) magnetic field on the Huygens' equivalent surface is obtained using the FDTD method by considering the complex field-tissue interactions within the human body model. The obtained magnetic field distributed on the Huygens' equivalent surface is regarded as the next target. The current density on the designated source surface is derived using the inverse method. The homogeneity of target magnetic field and specific energy absorption rate are calculated to verify the proposed method.

  19. Interspecies Interactions in Relation to Root Distribution Across the Rooting Profile in Wheat-Maize Intercropping Under Different Plant Densities

    Directory of Open Access Journals (Sweden)

    Yifan Wang

    2018-04-01

    Full Text Available In wheat-maize intercropping systems, the maize is often disadvantageous over the wheat during the co-growth period. It is unknown whether the impaired growth of maize can be recovered through the enhancement of the belowground interspecies interactions. In this study, we (i determined the mechanism of the belowground interaction in relation to root growth and distribution under different maize plant densities, and (ii quantified the “recovery effect” of maize after wheat harvest. The three-year (2014–2016 field experiment was conducted at the Oasis Agriculture Research Station of Gansu Agricultural University, Wuwei, Northwest China. Root weight density (RWD, root length density (RLD, and root surface area density (RSAD, were measured in single-cropped maize (M, single-cropped wheat (W, and three intercropping systems (i wheat-maize intercropping with no root barrier (i.e., complete belowground interaction, IC, (ii nylon mesh root barrier (partial belowground interaction, IC-PRI, and (iii plastic sheet root barrier (no belowground interaction, IC-NRI. The intercropped maize was planted at low (45,000 plants ha−1 and high (52,000 plants ha−1 densities. During the wheat/maize co-growth period, the IC treatment increased the RWD, RLD, and RSAD of the intercropped wheat in the 20–100 cm soil depth compared to the IC-PRI and IC-NRI systems; intercropped maize had 53% lower RWD, 81% lower RLD, and 70% lower RSAD than single-cropped maize. After wheat harvest, the intercropped maize recovered the growth with the increase of RWD by 40%, RLD by 44% and RSAD by 11%, compared to the single-cropped maize. Comparisons among the three intercropping systems revealed that the “recovery effect” of the intercropped maize was attributable to complete belowground interspecies interaction by 143%, the compensational effect due to root overlap by 35%, and the compensational effect due to water and nutrient exchange (CWN by 80%. The higher maize plant

  20. High density renal medulla on unenhanced CT : significance and relation with hydration status

    International Nuclear Information System (INIS)

    Lee, Eun Jung; Kim, Hyun Suk; Oh, Kyung Seung; Kim, Jong Min; Kim, Sung Min; Jung, Gyoo Sik; Huh, Jin Do; Joh, Young Duk

    1999-01-01

    To assess the effect of hydration status on renal medullary attenuation and to evaluate the incidence of dense renal medulla, as seen on unenhanced CT. We prospectively studied unenhanced CT scans of 12 healthy volunteers. Obtained done after 10 hours and 15 hours of dehydration and after oral intake of 2L of water. BUN/Cr, urine specific gravity, urine osmole and hematocrit were evaluated after 10 hours of dehydration. CT images were reviewed for the presence of dense renal medulla and differential attenuation of dense renal and isodense medulla and cortex at the same level. The density changes of renal medulla after hydration were evaluated. and CT findings were compared with the results of biochemical studies. In addition, we retrospectively reviewed the CT scans of 200 consecutive patients for evaluation of the incidence of dense renal medulla. In 8 of 12 volunteers, dense renal medulla was seen on CT scan after dehydration. Mean attenuation was 71.3±10.42HU after 10 hours of dehydration, 68.6±13.54HU after 15 hours, and 34.5±11.47HU after hydration. No significant attenuation differences were detected between 10 hours and 15 hours of dehydration, but significantly lower attenuation values were noted after hydration. For isodense medulla, the mean attenuation value was 35.7±7.9HU after 10 hours of dehydration, 39.58±9.66HU after 15 hours, and 36.58±7.77HU after hydration. The mean attenuation values of cortex were 35.9±5.95HU after 10 hours of dehydration. 37.58±5.95HU after 15 hours, and 37.08±9.75HU after hydration. With regard not only to duration of dehydration, but also ti hydration, no differences in attenuation values were noted for renal cortex or isodense renal medulla. However, higher density was noted in dense renal medulla than in isodense medulla or cortex for the same duration of dehydration. After hydration, complete resolution was seen at five of eight sites and incomplete resolution at three of eight sites. There was no correlation

  1. Are serotonin metabolite levels related to bone mineral density in patients with neuroendocrine tumours?

    Science.gov (United States)

    Sen Gupta, Piya; Grozinsky-Glasberg, Simona; Drake, William M; Akker, Scott A; Perry, Les; Grossman, Ashley B; Druce, Maralyn R

    2014-02-01

    Bone mineral density (BMD) is influenced by multiple factors. Recent studies have highlighted a possible relationship between serotonin and BMD. Patients with neuroendocrine tumours (NETs) frequently have elevated urinary 5-hydroxy-indoleacetic acid (5-HIAA) levels, a serotonin metabolite. Evaluation of the relationship between 5-HIAA and BMD in patients with NETs may provide insights into the relationship between serotonin and BMD. One-year audit of consecutive patients with NETs within two institutions. Relationships between urinary 5-HIAA and dual X-ray absorptiometry (DEXA)-scan-measured BMD were investigated by group comparisons, correlation and regression. Of 65 patients with NETs, 19 did not participate or were excluded. Of 46 subjects evaluated (48·9% males, 63·8 ± 10·5 years, BMI 26·6 ± 4·4 kg/m(2) ) with 32 gastrointestinal, 9 pancreatic, 3 pulmonary and 2 ovarian NETs, 72·3% had the carcinoid syndrome. Median interval from diagnosis was 4·0 years (IQR 2·0-6·0); 41·3% had osteoporosis and 32·6% osteopaenia (WHO definition). The group with a higher urinary 5-HIAA had a lower hip BMD (total T-score and Z-score), confirmed on individual analysis (Spearman's rank correlation -0·41, P = 0·004; -0·44, P = 0·002, respectively); urinary 5-HIAA was not found to be an independent predictor for BMD on multiple linear regression analysis. These data of patients with NETs with higher serotonin metabolites having a lower BMD at the hip in group and individual comparisons, warrants further evaluation. Urinary 5-HIAA measurement alone cannot be used to predict future BMD. A larger cohort with prospective design including fractures as a clinical outcome will aid these data in determining whether patients with NETs should be subject to targeted osteoporosis prevention. © 2013 John Wiley & Sons Ltd.

  2. [Low bone mineral density in juvenile idiopathic arthritis: Prevalence and related factors].

    Science.gov (United States)

    Galindo Zavala, Rocío; Núñez Cuadros, Esmeralda; Martín Pedraz, Laura; Díaz-Cordovés Rego, Gisela; Sierra Salinas, Carlos; Urda Cardona, Antonio

    2017-10-01

    Height adjustment is currently recommended for Z-score bone mineral density (BMD) assessed by dual energy X-ray absorptiometry. At present there are no studies that evaluate the prevalence of low BMD in paediatric patients with Juvenile Idiopathic Arthritis (JIA) in Spain following current recommendations. To evaluate low BMD in JIA in paediatric patients with JIA in Spain following the latest recommendations, as well as to assess associated factors. Observational cross-sectional study of Spanish JIA patients from 5 to 16 years-old, followed-up in a Paediatric Rheumatology Unit between July 2014 and July 2015. Anthropometric, clinical and treatment data were recorded. Dual energy X-ray absorptiometry, and bone metabolism parameters were collected, and a completed diet and exercise questionnaire was obtained. A total of 92 children participated. The population prevalence estimation of low BMD was less than 5% (95% CI). A significant positive correlation was found in the multiple linear regression analysis between the body mass index percentile (B: 0.021; P<.001) and lean mass index (B: 0.0002; P=.012), and BMD Z-score adjusted for height (Z-SAH). A significant negative correlation was found between fat mass index (B: -0.0001; P=.018) and serum type I collagen N-propeptide (B: -0,0006; P=.036) and Z-SAH. Low BMD prevalence in JIA patients in our population is low. An adequate nutritional status and the prevalence of lean over fat mass seem to promote the acquisition of bone mass. Those JIA patients with lower BMD could be subjected to an increase of bone turnover. Copyright © 2016 Asociación Española de Pediatría. Publicado por Elsevier España, S.L.U. All rights reserved.

  3. Lifetime physical activity and calcium intake related to bone density in young women.

    Science.gov (United States)

    Wallace, Lorraine Silver; Ballard, Joyce E

    2002-05-01

    Osteoporosis is a significant public health problem associated with increased mortality and morbidity. Our aim in this cross-sectional study was to investigate the relationship between lifetime physical activity and calcium intake and bone mineral density (BMD) and BMC (bone mineral content) in 42 regularly menstruating Caucasian women (age 21.26+/-1.91 years, BMI 23.83+/-5.85). BMD and BMC at the lumbar spine (L2-L4), hip (femoral neck, trochanter, total), and total body were assessed by dual energy x-ray absorptiometry (DXA). Lifetime history of physical activity and calcium intake was obtained by a structured interview using valid and reliable instruments. Measures of both lifetime physical activity and calcium intake were highly correlated. In stepwise multiple regression analyses, lean mass was the most important and consistent factor for predicting BMD and BMC at all skeletal sites (attributable r2 = 28.8%-78.7%). Lifetime physical activity contributed to 3.0% of the variation in total body BMD, and life-time weight-bearing physical activity explained 15.1% of variance in lumbar spine BMC. Current calcium intake predicted 6% of the variance in BMD at the femoral neck and trochanter. We found lean mass to be a powerful predictor of BMD and BMC in young women. Because lean mass can be modified to some extent by physical activity, public health efforts must be directed at increasing physical activity throughout the lifespan. Furthermore, our results suggest that adequate calcium intake may help to enhance bone mass, thus decreasing the risk of osteoporotic fracture later in life.

  4. ALK1 expression in oral lichen planus: a possible relation to microvessel density.

    Science.gov (United States)

    Hazzaa, Hala H A; El-Wakeel, Naglaa M; Attia, Enas A S; Abo Hager, Eman A

    2016-05-01

    To assess the expression of activin receptor-like kinase 1 (ALK1) and investigate its possible relationship with microvessel density (MVD) in different forms of oral lichen planus (OLP) compared to controls' biopsies. Biopsies from 20 reticular/papular OLP (R/PLP), 20 atrophic/erosive OLP (A/ELP) patients, and 20 healthy subjects were immunohistochemically analyzed and statistically compared and correlated for ALK1 expression and MVD as assessed by CD34 expression. All OLP specimens revealed the presence of positive cytoplasmic CD34 immunostaining in endothelial cells, with statistically high significant MVD in each of R/PLP (Median; M = 4.40) and A/ELP (M = 7.69) compared to controls (M = 1.16) (P < 0.001). Statistically significant MVD was found in A/ELP compared to R/PLP (P < 0.001). All control specimens revealed negative ALK1 immunostaining of the few inflammatory cells found, while 85% of A/ELP cases and 70% of R/PLP cases showed positively immunostained sections for ALK-1, with statistically significant higher ALK1 expression In A/ELP (M = 1.95) compared to R/PLP (M = 0.86) (P = 0.005). No significant correlation between CD34 and ALK1 was detected in R/PLP (r = 0.081), while a barely moderate positive correlation was found in A/ELP (r = 0.396). ALK1 expression and MVD are increased in OLP, particularly in A/ELP type. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  5. Public support for river restoration funding in relation to local river ecomorphology, population density, and mean income

    Science.gov (United States)

    SchläPfer, Felix; Witzig, Pieter-Jan

    2006-12-01

    In 1997, about 140,000 citizens in 388 voting districts in the Swiss canton of Bern passed a ballot initiative to allocate about 3 million Swiss Francs annually to a canton-wide river restoration program. Using the municipal voting returns and a detailed georeferenced data set on the ecomorphological status of the rivers, we estimate models of voter support in relation to local river ecomorphology, population density, mean income, cultural background, and recent flood damage. Support of the initiative increased with increasing population density and tended to increase with increasing mean income, in spite of progressive taxation. Furthermore, we found evidence that public support increased with decreasing "naturalness" of local rivers. The model estimates may be cautiously used to predict the public acceptance of similar restoration programs in comparable regions. Moreover, the voting-based insights into the distribution of river restoration benefits provide a useful starting point for debates about appropriate financing schemes.

  6. Effect of Austenite Deformation on the Microstructure Evolution and Grain Refinement Under Accelerated Cooling Conditions

    Science.gov (United States)

    Zhao, H.; Palmiere, E. J.

    2017-07-01

    Although there has been much research regarding the effect of austenite deformation on accelerated cooled microstructures in microalloyed steels, there is still a lack of accurate data on boundary densities and effective grain sizes. Previous results observed from optical micrographs are not accurate enough, because, for displacive transformation products, a substantial part of the boundaries have disorientation angles below 15 deg. Therefore, in this research, a niobium microalloyed steel was used and electron backscattering diffraction mappings were performed on all of the transformed microstructures to obtain accurate results on boundary densities and grain refinement. It was found that with strain rising from 0 to 0.5, a transition from bainitic ferrite to acicular ferrite occurs and the effective grain size reduces from 5.7 to 3.1 μm. When further increasing strain from 0.5 to 0.7, dynamic recrystallization was triggered and postdynamic softening occurred during the accelerated cooling, leading to an inhomogeneous and coarse transformed microstructure. In the entire strain range, the density changes of boundaries with different disorientation angles are distinct, due to different boundary formation mechanisms. Finally, the controversial influence of austenite deformation on effective grain size of low-temperature transformation products was argued to be related to the differences in transformation conditions and final microstructures.

  7. Nest site preference depends on the relative density of conspecifics and heterospecifics in wild birds

    NARCIS (Netherlands)

    Samplonius, Jelmer M.; Kromhout Van Der Meer, Iris M; Both, Christiaan

    2017-01-01

    Background: Social learning allows animals to eavesdrop on ecologically relevant knowledge of competitors in their environment. This is especially important when selecting a habitat if individuals have relatively little personal information on habitat quality. It is known that birds can use both

  8. Density and distribution of cutaneous sensilla on tails of leopard geckos (Eublepharis macularius) in relation to caudal autotomy.

    Science.gov (United States)

    Russell, Anthony P; Lai, Erica K; Lawrence Powell, G; Higham, Timothy E

    2014-09-01

    The lizard tail is well known for its ability to autotomize and regenerate. Physical contact of the tail by a predator may induce autotomy at the location at which the tail is grasped, and upon detachment the tail may undergo violent, rapid, and unpredictable movements that appear to be, to some degree, regulated by contact with the physical environment. Neither the mechanism by which tail breakage at a particular location is determined, nor that by which environmental feedback to the tail is received, are known. It has been suggested that mechanoreceptors (sensilla) are the means of mediation of such activities, and reports indicate that the density of sensilla on the tail is high. To determine the feasibility that mechanoreceptors are involved in such phenomena, we mapped scale form and the size, density, distribution, and spacing of sensilla on the head, body, limbs, and tail of the leopard gecko. This species has a full complement of autotomy planes along the length of the tail, and the postautotomic behavior of its tail has been documented. We found that the density of sensilla is highest on the tail relative to all other body regions examined; a dorsoventral gradient of caudal sensilla density is evident on the tail; sensilla are more closely spaced on the dorsal and lateral regions of the tail than elsewhere and are carried on relatively small scales; and that the whorls of scales on the tail bear a one to one relationship with the autotomy planes. Our results are consistent with the hypotheses of sensilla being involved in determining the site at which autotomy will occur, and with them being involved in the mediation of tail behavior following autotomy. These findings open the way for experimental neurological investigations of how autotomy is induced and how the detached tail responds to external environmental input. © 2014 Wiley Periodicals, Inc.

  9. Manganese concentrations in the air of the Montreal (Canada) subway in relation to surface automobile traffic density

    Energy Technology Data Exchange (ETDEWEB)

    Boudia, Nacera; Gareau, Lise; Zayed, Joseph [GRIS Interdisciplinary Health Research Group, University of Montreal (Canada); Halley, Renee [Transport Montreal Society (Canada); Kennedy, Greg [Department of Engineering Physics, Ecole Polytechnique de Montreal, Montreal (Canada); Lambert, Jean [Department of Social and Preventive Medicine, Faculty of Medicine, University of Montreal (Canada)

    2006-07-31

    Methylcyclopentadienyl manganese tricarbonyl (MMT) is an organic derivative of manganese (Mn), used since 1976 in Canadian gasoline as an octane enhancer. Its combustion leads to the emission of Mn particles. Several studies carried out by our research group have established a correlation between atmospheric Mn concentrations and automobile traffic density, suggesting that MMT in gasoline could play a significant role. This study aims to measure Mn concentrations in the air of the underground subway in Montreal (Canada) and to examine the relation with nearby surface automobile traffic density and, by extension, with the use of MMT in gasoline. Three subway stations were chosen for their location in different microenvironments with different traffic densities. Respirable (MnR<5 {mu}m) and total Mn (MnT) were sampled over two weeks, 5 days/week, 12 h/day. For the station located in the lower traffic density area, relatively low levels of MnR and MnT were found, with averages of 0.018 and 0.032 {mu}g/m{sup 3}, respectively. These concentrations are within the range of the background levels in Montreal. For the other two stations, the average concentrations of MnR were twice as high and exceeded the US EPA reference concentration of 0.05 {mu}g/m{sup 3}. Although there may be several sources of Mn from different components of the subway structure and vehicles, no correlation was found between subway traffic and atmospheric Mn in the subway. Since the air in the underground subway is pumped directly from outside without filtration, our findings strongly suggest that the combustion of MMT in automobiles is an important factor. (author)

  10. NODDI and Tensor-Based Microstructural Indices as Predictors of Functional Connectivity.

    Directory of Open Access Journals (Sweden)

    Fani Deligianni

    Full Text Available In Diffusion Weighted MR Imaging (DWI, the signal is affected by the biophysical properties of neuronal cells and their relative placement, as well as extra-cellular tissue compartments. Typically, microstructural indices, such as fractional anisotropy (FA and mean diffusivity (MD, are based on a tensor model that cannot disentangle the influence of these parameters. Recently, Neurite Orientation Dispersion and Density Imaging (NODDI has exploited multi-shell acquisition protocols to model the diffusion signal as the contribution of three tissue compartments. NODDI microstructural indices, such as intra-cellular volume fraction (ICVF and orientation dispersion index (ODI are directly related to neuronal density and orientation dispersion, respectively. One way of examining the neurophysiological role of these microstructural indices across neuronal fibres is to look into how they relate to brain function. Here we exploit a statistical framework based on sparse Canonical Correlation Analysis (sCCA and randomised Lasso to identify structural connections that are highly correlated with resting-state functional connectivity measured with simultaneous EEG-fMRI. Our results reveal distinct structural fingerprints for each microstructural index that also reflect their inter-relationships.

  11. Preparation, microstructures, and properties of PuO2

    International Nuclear Information System (INIS)

    Bickford, D.F.; Rankin, D.T.; Smith, P.K.

    1976-01-01

    PuO 2 pellets with controlled microstructures were fabricated to meet operational requirements for packaged heat sources. Size distributions, morphologies (forms and structures), and packing densities were measured on calcined and milled powders, slugged compacts, and presintered granules. These variables influence microstructure, porosity distribution, and fracture behavior of hot-pressed and sintered PuO 2

  12. Are color or high rearing density related to migratory polyphenism in the band-winged grasshopper, Oedaleus asiaticus?

    Science.gov (United States)

    Cease, Arianne J; Hao, Shuguang; Kang, Le; Elser, James J; Harrison, Jon F

    2010-08-01

    Locusts represent an impressive example of migratory polyphenism, with high densities triggering a switch from a solitarious, shorter dispersal range, and sometimes greenish phenotype to a gregarious and sometimes darker form exhibiting behavioral, morphological and physiological traits associated with long-distance migratory swarms. While such polyphenism has been well documented in Locusta migratoria and Schistocerca gregaria, the extent to which other grasshoppers exhibit this type of migratory polyphenism is unclear. Anecdotally, the Chinese grasshopper, Oedaleus asiaticus, forms migratory swarms comprised mostly of a darker, brown-colored morph, but also exhibits a non-migratory green-colored morph that predominates at low densities. In a population in Inner Mongolia not currently exhibiting migratory swarms, we found that while green and brown O. asiaticus are found concurrently across our sampled range, only brown grasshoppers were found in high densities. Differences between field-collected brown and green forms matched some but not key predictions associated with the hypothesis that the brown form is morphologically and physiologically specialized for gregarious migration. Controlling for body mass, brown forms had more massive thoraxes, abdomens and legs, and higher metabolic rates, but not more flight muscle or lipid stores. Further, the brown and green grasshoppers did not differ in gregarious behavior, and neither would fly in multiple lab and field trials. Lab or field-rearing at high densities for one-to-multiple juvenile instars caused grasshoppers to exhibit some morphological traits predicted to benefit migration (larger wings and a shift in relative mass from abdomen to thorax), but did not change color or induce flight behavior. One hypothesis to explain these data is that a migratory form of O. asiaticus is partially triggered by high field densities, but that existing ecological conditions blocked full expression of such traits (and outbreak

  13. Microstructural and mechanical characterization of injection molded 718 superalloy powders

    Energy Technology Data Exchange (ETDEWEB)

    Özgün, Özgür [Bingol University, Faculty of Engineering and Architecture, Mechanical Eng. Dep., 12000 Bingol (Turkey); Gülsoy, H. Özkan, E-mail: ogulsoy@marmara.edu.tr [Marmara University, Technology Faculty, Metallurgy and Materials Eng. Dep., 34722 Istanbul (Turkey); Yılmaz, Ramazan [Sakarya University, Technology Faculty, Metallurgy and Materials Eng. Dep., 54187 Sakarya (Turkey); Fındık, Fehim [Sakarya University, Technology Faculty, Metallurgy and Materials Eng. Dep., 54187 Sakarya (Turkey) and International University of Sarajevo, Faculty of Engineering and Natural Sciences, Department of Mechanical Engineering, 71000 Sarajevo, Bosnia and Herzegovina (Bosnia and Herzegowina)

    2013-11-05

    Highlights: •Microstructural and mechanical properties of injection molded Nickel 718 superalloy were studied. •The maximum sintered density achieved this study was 97.3% at 1290 °C for 3 hours. •Tensile strength of 1022 MPa and elongation of 5.3% were achieved for sintered-heat treated samples. -- Abstract: This study concerns with the determination of optimum production parameters for injection molding 718 superalloy parts. And at the same time, microstructural and mechanical characterization of these produced parts was also carried out. At the initial stage, 718 superalloy powders were mixed with a multi-component binder system for preparing feedstock. Then the prepared feedstock was granulated and shaped by injection molding. Following this operation, the shaped samples were subjected to the debinding process. These samples were sintered at different temperatures for various times. Samples sintered under the condition that gave way to the highest relative density (3 h at 1290 °C) were solution treated and aged respectively. Sintered, solution treated and aged samples were separately subjected to microstructural and mechanical characterization. Microstructural characterization operations such as X-ray diffraction, optical microscope (OM), scanning electron microscope (SEM), transmission electron microscope (TEM) and elemental analysis showed that using polymeric binder system led to plentiful carbide precipitates to be occurred in the injection molded samples. It is also observed that the volume fractions of the intermetallic phases (γ′ and γ″) obtained by aging treatment were decreased due to the plentiful carbide precipitation in the samples. Mechanical characterization was performed by hardness measurements and tensile tests.

  14. Coarse-grained models using local-density potentials optimized with the relative entropy: Application to implicit solvation

    International Nuclear Information System (INIS)

    Sanyal, Tanmoy; Shell, M. Scott

    2016-01-01

    Bottom-up multiscale techniques are frequently used to develop coarse-grained (CG) models for simulations at extended length and time scales but are often limited by a compromise between computational efficiency and accuracy. The conventional approach to CG nonbonded interactions uses pair potentials which, while computationally efficient, can neglect the inherently multibody contributions of the local environment of a site to its energy, due to degrees of freedom that were coarse-grained out. This effect often causes the CG potential to depend strongly on the overall system density, composition, or other properties, which limits its transferability to states other than the one at which it was parameterized. Here, we propose to incorporate multibody effects into CG potentials through additional nonbonded terms, beyond pair interactions, that depend in a mean-field manner on local densities of different atomic species. This approach is analogous to embedded atom and bond-order models that seek to capture multibody electronic effects in metallic systems. We show that the relative entropy coarse-graining framework offers a systematic route to parameterizing such local density potentials. We then characterize this approach in the development of implicit solvation strategies for interactions between model hydrophobes in an aqueous environment.

  15. Fall-related self-efficacy, not balance and mobility performance, is related to accidental falls in chronic stroke survivors with low bone mineral density.

    Science.gov (United States)

    Pang, M Y C; Eng, J J

    2008-07-01

    Chronic stroke survivors with low hip bone density are particularly prone to fractures. This study shows that fear of falling is independently associated with falls in this population. Thus, fear of falling should not be overlooked in the prevention of fragility fractures in these patients. Chronic stroke survivors with low bone mineral density (BMD) are particularly prone to fragility fractures. The purpose of this study was to identify the determinants of balance, mobility and falls in this sub-group of stroke patients. Thirty-nine chronic stroke survivors with low hip BMD (T-score fall-related self-efficacy. Any falls in the past 12 months were also recorded. Multiple regression analysis was used to identify the determinants of balance and mobility performance, whereas logistic regression was used to identify the determinants of falls. Multiple regression analysis revealed that after adjusting for basic demographics, fall-related self-efficacy remained independently associated with balance/mobility performance (R2 = 0.494, P fall-related self-efficacy, but not balance and mobility performance, was a significant determinant of falls (odds ratio: 0.18, P = 0.04). Fall-related self-efficacy, but not mobility and balance performance, was the most important determinant of accidental falls. This psychological factor should not be overlooked in the prevention of fragility fractures among chronic stroke survivors with low hip BMD.

  16. Neuronal low-density lipoprotein receptor-related protein 1 binds and endocytoses prion fibrils via receptor cluster 4

    DEFF Research Database (Denmark)

    Jen, Angela; Parkyn, Celia J; Mootoosamy, Roy C

    2010-01-01

    For infectious prion protein (designated PrP(Sc)) to act as a template to convert normal cellular protein (PrP(C)) to its distinctive pathogenic conformation, the two forms of prion protein (PrP) must interact closely. The neuronal receptor that rapidly endocytoses PrP(C) is the low......-density lipoprotein receptor-related protein 1 (LRP1). We show here that on sensory neurons LRP1 is also the receptor that binds and rapidly endocytoses smaller oligomeric forms of infectious prion fibrils, and recombinant PrP fibrils. Although LRP1 binds two molecules of most ligands independently to its receptor...... both prion and LRP1 biology....

  17. Age- and gender-related distribution of bone mineral density and mechanical properties of the proximal humerus

    International Nuclear Information System (INIS)

    Lill, H.; Hepp, P.; Korner, J.; Josten, C.; Gowin, W.; Oestmann, J.W.; Haas, N.P.; Duda, G.N.

    2002-01-01

    Purpose: To evaluate age- and gender-related mechanical properties and bone mineral density (BMD) of the proximal humerus at different levels and regions. Materials and methods: Mechanical indentation testing, DXA, QCT, pQCT and the radiogrammetry (Cortical Index, CI) were carried out in 70 freshly harvested humeri from 46 human cadavers (23 females, 23-males; median age 70.5 years). Results: In the female group, a high correlation between age and BMD was found (ρ=0.62 to -0.70, p [de

  18. Striated muscle fiber size, composition and capillary density in diabetes in relation to neuropathy and muscle strength

    DEFF Research Database (Denmark)

    Andreassen, Christer Swan; Jensen, Jacob Malte; Jakobsen, Johannes

    2014-01-01

    study was to evaluate histologic properties and capillarization of diabetic skeletal muscle in relation to DPN and muscle strength. METHODS: Twenty type 1 and 20 type 2 diabetic (T1D and T2D, respectively) patients underwent biopsy of the gastrocnemic muscle, isokinetic dynamometry at the ankle...... between muscle fiber diameter, muscle fiber type distribution, or capillary density and degree of neuropathy or muscle strength for either patient group. Muscle fiber diameter and the proportion of Type II fibers were greater for T1D patients than both T2D patients and controls. The T2D patients had fewer...

  19. Association between mammographic density and pregnancies relative to age and BMI: a breast cancer case-only analysis.

    Science.gov (United States)

    Hack, Carolin C; Emons, Julius; Jud, Sebastian M; Heusinger, Katharina; Adler, Werner; Gass, Paul; Haeberle, Lothar; Heindl, Felix; Hein, Alexander; Schulz-Wendtland, Rüdiger; Uder, Michael; Hartmann, Arndt; Beckmann, Matthias W; Fasching, Peter A; Pöhls, Uwe G

    2017-12-01

    Percentage mammographic density (PMD) is a major risk factor for breast cancer (BC). It is strongly associated with body mass index (BMI) and age, which are themselves risk factors for breast cancer. This analysis investigated the association between the number of full-term pregnancies and PMD in different subgroups relative to age and BMI. Patients were identified in the breast cancer database of the University Breast Center for Franconia. A total of 2410 patients were identified, for whom information on parity, age, and BMI, and a mammogram from the time of first diagnosis were available for assessing PMD. Linear regression analyses were conducted to investigate the influence on PMD of the number of full-term pregnancies (FTPs), age, BMI, and interaction terms between them. As in previous studies, age, number of FTPs, and BMI were found to be associated with PMD in the expected direction. However, including the respective interaction terms improved the prediction of PMD even further. Specifically, the association between PMD and the number of FTPs differed in young patients under the age of 45 (mean decrease of 0.37 PMD units per pregnancy) from the association in older age groups (mean decrease between 2.29 and 2.39 PMD units). BMI did not alter the association between PMD and the number of FTPs. The effect of pregnancies on mammographic density does not appear to become apparent before the age of menopause. The mechanism that drives the effect of pregnancies on mammographic density appears to be counter-regulated by other influences on mammographic density in younger patients.

  20. Moderate and late preterm infants exhibit widespread brain white matter microstructure alterations at term-equivalent age relative to term-born controls

    NARCIS (Netherlands)

    Kelly, Claire E.; Cheong, Jeanie L Y; Gabra Fam, Lillian; Leemans, Alexander; Seal, Marc L.; Doyle, Lex W.; Anderson, Peter J.; Spittle, Alicia J.; Thompson, Deanne K.

    2016-01-01

    Despite the many studies documenting cerebral white matter microstructural alterations associated with very preterm birth (<32 weeks’ gestation), there is a dearth of similar research in moderate and late preterm infants (born 32–36 weeks’ gestation), who experience higher rates of

  1. The multiligand α2-macroglobulin receptor/low density lipoprotein receptor-related protein

    DEFF Research Database (Denmark)

    Gliemann, Jørgen; Nykjær, Anders; Petersen, Claus Munck

    1994-01-01

    The fusion of separate lines of research has greatly helped in elucidating the function of the giant members of the low density lipoprotein (LDL) receptor (LDLR) supergene family. The cDNA encoding a large protein structurally closely related to LDLR, and hence named LDLR-related protein (LRP......), was cloned by Herz et al. in 1988.'Evidence was provided demonstrating that LRP can function as a receptor for chylomicron remnants@-migrating very low density lipoproteins (P-VLDL) rich in apolipoprotein E (apoE)?' The a2-macroglobulin (a2M) receptor (a2MR) was purified from rat livep and human p l a~e n t...... from the observation that affinity-purified a2MR/LRP contains a 40-kDa5.8 or 39-kDa6.' protein, designated a2MRAP, in addition to the a2MFULRP a- and P-chains. cDNA cloning" disclosed the 323-residue protein as both the human homologue of mouse heparin binding protein 44 (see reference 11) and...

  2. Assessment of the microstructure evolution of an austempered ductile iron during austempering process through strain hardening analysis

    Science.gov (United States)

    Donnini, Riccardo; Fabrizi, Alberto; Bonollo, Franco; Zanardi, Franco; Angella, Giuliano

    2017-09-01

    The aim of this investigation was to determine a procedure based on tensile testing to assess the critical range of austempering times for having the best ausferrite produced through austempering. The austempered ductile iron (ADI) 1050 was quenched at different times during austempering and the quenched samples were tested in tension. The dislocation-density-related constitutive equation proposed by Estrin for materials having high density of geometrical obstacles to dislocation motion, was used to model the flow curves of the tensile tested samples. On the basis of strain hardening theory, the equation parameters were related to the microstructure of the quenched samples and were used to assess the ADI microstructure evolution during austempering. The microstructure evolution was also analysed through conventional optical microscopy, electron back-scattered diffraction technique and transmission electron microscopy. The microstructure observations resulted to be consistent with the assessment based on tensile testing, so the dislocation-density-related constitutive equation was found to be a powerful tool to characterise the evolution of the solid state transformations of austempering.

  3. When strong unions meet precarious migrants: Building trustful relations to unionise labour migrants in a high union-density setting

    DEFF Research Database (Denmark)

    Refslund, Bjarke

    2018-01-01

    Based on case studies in a fish processing plant and a demolition company, this article shows how strong and institutionally embedded unions interact with migrant workers in a precarious labour market position in order to safeguard their working conditions and organise them. It shows how strong...... in the IR-model. The dynamic relation between migrant workers and national unions in this high-density setting is discussed emphasising the need for building a trustful relation between the migrant workers and the unions in order to empower the migrants to better navigate in the national labour market...... unions are in a good position to include migrant workers and thereby resist labour market segmentation. The strong Danish unions, faced with the serious challenges of intra-European labour migration, have increased their attention and resources devoted to organising migrant workers and including them...

  4. Power spectral density analysis of wind-shear turbulence for related flight simulations. M.S. Thesis

    Science.gov (United States)

    Laituri, Tony R.

    1988-01-01

    Meteorological phenomena known as microbursts can produce abrupt changes in wind direction and/or speed over a very short distance in the atmosphere. These changes in flow characteristics have been labelled wind shear. Because of its adverse effects on aerodynamic lift, wind shear poses its most immediate threat to flight operations at low altitudes. The number of recent commercial aircraft accidents attributed to wind shear has necessitated a better understanding of how energy is transferred to an aircraft from wind-shear turbulence. Isotropic turbulence here serves as the basis of comparison for the anisotropic turbulence which exists in the low-altitude wind shear. The related question of how isotropic turbulence scales in a wind shear is addressed from the perspective of power spectral density (psd). The role of the psd in related Monte Carlo simulations is also considered.

  5. MICROSTRUCTURE OF SUPERCONDUCTING MGB(2).

    Energy Technology Data Exchange (ETDEWEB)

    ZHU,Y.; LI,Q.; WU,L.; VOLKOV,V.; GU,G.; MOODENBAUGH,A.R.

    2001-07-12

    Recently, Akimitsu and co-workers [1] discovered superconductivity at 39 K in the intermetallic compound MgB{sub 2}. This discovery provides a new perspective on the mechanism for superconductivity. More specifically, it opens up possibilities for investigation of structure/properties in a new class of materials. With the exceptions of the cuprate and C{sub 60} families of compounds, MgB{sub 2} possesses the highest superconducting transition temperature T{sub c}. Its superconductivity appears to follow the BCS theory, apparently being mediated by electron-phonon coupling. The coherence length of MgB{sub 2} is reported to be longer than that of the cuprates [2]. In contrast to the cuprates, grain boundaries are strongly coupled and current density is determined by flux pinning [2,3]. Presently, samples of MgB{sub 2} commonly display inhomogeneity and porosity on the nanoscale, and are untextured. In spite of these obstacles, magnetization and transport measurements show that polycrystalline samples may carry large current densities circulating across many grains [3,4]. Very high values of critical current densities and critical fields have been recently observed in thin films [5,6]. These attributes suggest possible large scale and electronic applications. The underlying microstructure can be intriguing, both in terms of basic science and in applied areas. Subsequent to the discovery, many papers were published [1-13], most dealing with synthesis, physical properties, and theory. There have yet been few studies of microstructure and structural defects [11, 14]. A thorough understanding of practical superconducting properties can only be developed after an understanding of microstructure is gained. In this work we review transmission electron microscopy (TEM) studies of sintered MgB{sub 2} pellets [14]. Structural defects, including second phase particles, dislocations, stacking faults, and grain boundaries, are analyzed using electron diffraction, electron

  6. Autonomous patterning of cells on microstructured fine particles

    International Nuclear Information System (INIS)

    Takeda, Iwori; Kawanabe, Masato; Kaneko, Arata

    2015-01-01

    Regularly patterned cells can clarify cellular function and are required in some biochip applications. This study examines cell patterning along microstructures and the effect of microstructural geometry on selective cellular adhesion. Particles can be autonomously assembled on a soda-lime glass substrate that is chemically patterned by immersion in a suspension of fine particles. By adopting various sizes of fine particles, we can control the geometry of the microstructure. Cells adhere more readily to microstructured fine particles than to flat glass substrate. Silica particles hexagonally packed in 5–40 μm line and space microstructures provide an effective cell scaffold on the glass substrate. Cultured cells tend to attach and proliferate along the microstructured region while avoiding the flat region. The difference in cell adhesion is attributed to their geometries, as both of the silica particles and soda-lime glass are hydrophilic related with cell adhesiveness. After cell seeding, cells adhered to the flat region migrated toward the microstructured region. For most of the cells to assemble on the scaffold, the scaffolding microstructures must be spaced by at most 65 μm. - Highlights: • PS and SiO 2 particles provide effective scaffolds for cells. • Cells that adhere to microstructured particles successfully proliferate and differentiate. • Selective adhesion and growth along the scaffold can be achieved by patterning the fine particle microstructure. • Cells adhered to flat regions migrate toward microstructured regions. • Selective adhesion by cells depends on the microstructural geometry; specifically, on the inter-line spacing

  7. Microstructured reactor for electroorganic synthesis

    Energy Technology Data Exchange (ETDEWEB)

    Bouzek, Karel, E-mail: bouzekk@vscht.c [Department of Inorganic Technology, Institute of Chemical Technology Prague, Technicka 5, 166 28 Prague 6 (Czech Republic); Jiricny, Vladimir [Institute of Chemical Process Fundamentals, v.v.i., Academy of Sciences of the Czech Republic, Rozvojova 2, 165 02 Prague 6 (Czech Republic); Kodym, Roman [Department of Inorganic Technology, Institute of Chemical Technology Prague, Technicka 5, 166 28 Prague 6 (Czech Republic); Kristal, Jiri [Institute of Chemical Process Fundamentals, v.v.i., Academy of Sciences of the Czech Republic, Rozvojova 2, 165 02 Prague 6 (Czech Republic); Bystron, Tomas [Department of Inorganic Technology, Institute of Chemical Technology Prague, Technicka 5, 166 28 Prague 6 (Czech Republic)

    2010-11-30

    In the present work a brief overview of microstructured devices, the advantages and disadvantages as well as the principles of a multiscale design approach are presented. The advantages mainly comprise uniform current density distribution, local control of the process parameters, high single-pass conversion of the reactant and reduced concentration of the supporting electrolyte needed to perform the reaction. The main challenge with this type of cell is gas evolution, a typical reaction taking place at the counter-electrode. The phenomena discussed are documented using the example of anodic methoxylation of 4-methylanisole. An analysis was made of the two-phase flow hydrodynamics inside the microstructured cell. The range of operational conditions suitable for the desired reaction was identified. The results were used together with the information on the electrode reaction kinetics in the form of the Butler-Volmer-type equation for the design of a suitable bipolar microstructured cell. A bipolar cell optimized to perform the desired reaction is reported. The results are compared with the published data. An analysis was performed that proved that the performance of the existing technology is more demanding in terms of energy consumption for the separation of the final product from the reaction mixture. The process intensification was evaluated on the basis of the available data.

  8. The Influence of Spark Plasma Sintering Temperature on the Microstructure and the Thermoelectric Properties of Al, Ga dually-doped ZnO

    DEFF Research Database (Denmark)

    Han, Li; Le, Thanh Hung; Van Nong, Ngo

    2012-01-01

    Al, Ga dually-doped ZnO was prepared by spark plasma sintering with different sintering temperatures. The microstructural evolution and thermoelectric properties of the samples were investigated in detail. The samples with a sintering temperature above 1223K obtained higher relative densities...

  9. Family Density and SES Related to Diabetes Management and Glycemic Control in Adolescents With Type 1 Diabetes.

    Science.gov (United States)

    Caccavale, Laura J; Weaver, Patrick; Chen, Rusan; Streisand, Randi; Holmes, Clarissa S

    2015-06-01

    Youth with Type 1 diabetes (T1D) from single-parent families have poorer glycemic control; a finding confounded with socioeconomic status (SES). Family density (FD), or youth:adult ratio, may better characterize family risk status. Structural equation modeling assessed the relation of single-parent status, SES, and FD to parenting stress, diabetes-related conflict, parental monitoring, adherence, and glycemic control using cross-sectional parent and youth data (n = 257). Single-parent status exhibited similar relations as SES and was removed. Lower FD was associated with better glycemic control (β = -.29, p = .014) via less conflict (β = .17, p = .038) and greater adherence (β = -.54, p single-parent status were indistinguishable from those of SES. FD provides distinct information related to adolescent glycemic control. © The Author 2015. Published by Oxford University Press on behalf of the Society of Pediatric Psychology. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  10. Forest biomass density across large climate gradients in northern South America is related to water availability but not with temperature.

    Science.gov (United States)

    Álvarez-Dávila, Esteban; Cayuela, Luis; González-Caro, Sebastián; Aldana, Ana M; Stevenson, Pablo R; Phillips, Oliver; Cogollo, Álvaro; Peñuela, Maria C; von Hildebrand, Patricio; Jiménez, Eliana; Melo, Omar; Londoño-Vega, Ana Catalina; Mendoza, Irina; Velásquez, Oswaldo; Fernández, Fernando; Serna, Marcela; Velázquez-Rua, Cesar; Benítez, Doris; Rey-Benayas, José M

    2017-01-01

    Understanding and predicting the likely response of ecosystems to climate change are crucial challenges for ecology and for conservation biology. Nowhere is this challenge greater than in the tropics as these forests store more than half the total atmospheric carbon stock in their biomass. Biomass is determined by the balance between biomass inputs (i.e., growth) and outputs (mortality). We can expect therefore that conditions that favor high growth rates, such as abundant water supply, warmth, and nutrient-rich soils will tend to correlate with high biomass stocks. Our main objective is to describe the patterns of above ground biomass (AGB) stocks across major tropical forests across climatic gradients in Northwestern South America. We gathered data from 200 plots across the region, at elevations ranging between 0 to 3400 m. We estimated AGB based on allometric equations and values for stem density, basal area, and wood density weighted by basal area at the plot-level. We used two groups of climatic variables, namely mean annual temperature and actual evapotranspiration as surrogates of environmental energy, and annual precipitation, precipitation seasonality, and water availability as surrogates of water availability. We found that AGB is more closely related to water availability variables than to energy variables. In northwest South America, water availability influences carbon stocks principally by determining stand structure, i.e. basal area. When water deficits increase in tropical forests we can expect negative impact on biomass and hence carbon storage.

  11. Damage of Rhopalosiphum padi (L.) (Hemiptera: Aphididae) on wheat plants related to duration time and density of infestation

    International Nuclear Information System (INIS)

    Roza-Gomes, Margarida F.; Salvadori, Jose R.; Schons, Jurema

    2008-01-01

    Aphids are considered relevant pests on wheat either by direct damage through sap sucking or by indirect damage vectoring BYDV (Barley yellow dwarf virus). Rhopalosiphum padi L. has been observed infesting wheat fields with an increasing frequency. The knowledge and the available technology, besides being more related to other aphids species already recognized as pests, they are insufficient to control the specific c problem of R. padi. Thus, this work evaluated the effects of feeding duration and infestation densities of R. padi on seedlings of wheat cv. EMBRAPA 16. rain yield, yield components and the extent of symptoms were recorded. The experiment was carried out in the fi eld under a completely randomized split-plot experimental design with four replications. The main plot was feeding duration (two and seven days) and the sub-plots were infestation densities (zero, two and 10 aphids per plant). Independent on feeding duration, 10 aphids per plant resulted in significant yield losses, reduction of number of heads and tillers per plant. Canopy dry matter was also reduced. Infestations of two and 10 aphids per plant resulted in continuous yellowing of wheat plants from tillering to the end of flowering stage. When aphids fed for seven days on wheat, more yellowing symptoms were observed at the flower stage in comparison with two days feeding. (author)

  12. Transfer standard for the spectral density of relative intensity noise of optical fiber sources near 1550 nm

    International Nuclear Information System (INIS)

    Obarski, Gregory E.; Splett, Jolene D.

    2001-01-01

    We have developed a transfer standard for the spectral density of relative intensity noise (RIN) of optical fiber sources near 1550 nm. Amplified spontaneous emission (ASE) from an erbium-doped fiber amplifier (EDFA), when it is optically filtered over a narrow band (<5 nm), yields a stable RIN spectrum that is practically constant to several tens of gigahertz. The RIN is calculated from the power spectral density as measured with a calibrated optical spectrum analyzer. For a typical device it is -110 dB/Hz, with uncertainty ≤0.12 dB/Hz. The invariance of the RIN under attenuation yields a considerable dynamic range with respect to rf noise levels. Results are compared with those from a second method that uses a distributed-feedback laser (DFB) that has a Poisson-limited RIN. Application of each method to the same RIN measurement system yields frequency-dependent calibration functions that, when they are averaged, differ by ≤0.2 dB. [copyright] 2001 Optical Society of America

  13. Transfer standard for the spectral density of relative intensity noise of optical fiber sources near 1550 nm

    Energy Technology Data Exchange (ETDEWEB)

    Obarski, Gregory E.; Splett, Jolene D.

    2001-06-01

    We have developed a transfer standard for the spectral density of relative intensity noise (RIN) of optical fiber sources near 1550 nm. Amplified spontaneous emission (ASE) from an erbium-doped fiber amplifier (EDFA), when it is optically filtered over a narrow band ({lt}5 nm), yields a stable RIN spectrum that is practically constant to several tens of gigahertz. The RIN is calculated from the power spectral density as measured with a calibrated optical spectrum analyzer. For a typical device it is {minus}110 dB/Hz, with uncertainty {le}0.12 dB/Hz. The invariance of the RIN under attenuation yields a considerable dynamic range with respect to rf noise levels. Results are compared with those from a second method that uses a distributed-feedback laser (DFB) that has a Poisson-limited RIN. Application of each method to the same RIN measurement system yields frequency-dependent calibration functions that, when they are averaged, differ by {le}0.2 dB. {copyright} 2001 Optical Society of America

  14. Gray matter density of auditory association cortex relates to knowledge of sound concepts in primary progressive aphasia.

    Science.gov (United States)

    Bonner, Michael F; Grossman, Murray

    2012-06-06

    Long-term memory integrates the multimodal information acquired through perception into unified concepts, supporting object recognition, thought, and language. While some theories of human cognition have considered concepts to be abstract symbols, recent functional neuroimaging evidence has supported an alternative theory: that concepts are multimodal representations associated with the sensory and motor systems through which they are acquired. However, few studies have examined the effects of cortical lesions on the sensory and motor associations of concepts. We tested the hypothesis that individuals with disease in auditory association cortex would have difficulty processing concepts with strong sound associations (e.g., thunder). Human participants with the logopenic variant of primary progressive aphasia (lvPPA) performed a recognition task on words with strong associations in three modalities: Sound, Sight, and Manipulation. LvPPA participants had selective difficulty on Sound words relative to other modalities. Structural MRI analysis in lvPPA revealed gray matter atrophy in auditory association cortex, as defined functionally in a separate BOLD fMRI study of healthy adults. Moreover, lvPPA showed reduced gray matter density in the region of auditory association cortex that healthy participants activated when processing the same Sound words in a separate BOLD fMRI experiment. Finally, reduced gray matter density in this region in lvPPA directly correlated with impaired performance on Sound words. These findings support the hypothesis that conceptual memories are represented in the sensory and motor association cortices through which they are acquired.

  15. HIP (hot isostatic pressing) sintering of Tantalum (Ta) and tantalum carbide (TaC) powder mixture: relations between microstructure and properties

    International Nuclear Information System (INIS)

    Valin, F.; Schnedecker, M.

    1994-01-01

    HIP sintering at 1630 C and 195 MPa, during 2 hours, can be used for complete densification of mixtures of commercial tantalum carbide and tantalum powders. HIPed material properties are depending upon initial compositions. For C/Ta ratios inferior to 80%, the monocarbide structure is preserved. A partial ordering of the carbon vacancies will result, for TaC(0.80), in microhardness maximization. The microstructurally homogenous TaC(0.45) shows an excellent toughness. 2 figs., 2 refs

  16. Microstructural examination of commercial ferritic alloys at 299 DPA

    International Nuclear Information System (INIS)

    Gelles, D.S.

    1995-11-01

    Microstructures and density change measurements are reported for Martensitic commercial steels HT-9 and Modified 9Cr-lMo (T9) and oxide dispersion strengthened ferritic alloys MA956 and NU957 following irradiation in the FFTF/MOTA at 420 degrees C to 200 DPA. Swelling as determined by density change remains below 2% for all conditions. Microstructures are found to be stable except in recrystallized grains of MA957, which are fabrication artifacts, with only minor swelling in the Martensitic steels and α' precipitation in alloys with 12% or more chromium. These results further demonstrate the high swelling resistance and microstructural stability of the ferritic alloy class

  17. On-treatment non-high-density lipoprotein cholesterol, apolipoprotein B, triglycerides, and lipid ratios in relation to residual vascular risk after treatment with potent statin therapy

    DEFF Research Database (Denmark)

    Mora, Samia; Glynn, Robert J; Boekholdt, S Matthijs

    2012-01-01

    The goal of this study was to determine whether residual risk after high-dose statin therapy for primary prevention individuals with reduced levels of low-density lipoprotein cholesterol (LDL-C) is related to on-treatment apolipoprotein B, non-high-density lipoprotein cholesterol (non-HDL-C), tri...

  18. Investigation on the evolution of microstructure and texture of electroplated Ni–Ti composite coating by Rietveld method

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Yuantao, E-mail: zhaoyuantao@sjtu.edu.cn; Cai, Fei, E-mail: caifei32@126.com; Wang, Chengxi, E-mail: sjtucxw@sjtu.edu.cn; Chai, Ze, E-mail: zechaisjtu@163.com; Zhu, Kaiyuan, E-mail: xrd125@163.com; Xu, Zhou, E-mail: xuzhou@sjtu.edu.cn; Jiang, Chuanhai, E-mail: chjiang-sjtu@hotmail.com

    2015-10-30

    Highlights: • Ni–Ti composite coatings were prepared by electroplating. • Morphology and Ti content of Ni–Ti coatings were studied upon SEM and EDXS. • Microstructures of Ni–Ti coatings were studied upon the Rietveld method. • The texture of Ni–Ti coatings was studied upon the pole figure. - Abstract: Rietveld refinement was utilized to investigate the evolution of microstructure and texture of the Ni–Ti composite coatings electroplated at different applied current densities. Scanning Electron Microscope and Energy Dispersive Spectroscopy were utilized to investigate the morphology and chemical composition of the coatings. Relative texture coefficients (RTC) and measured pole figures were utilized to investigate the texture evolution of the coatings. The results showed that the surface morphology of the coatings changed from a colonial structure to a polyhedral one. And the incorporated Ti content decreased with increasing applied current density. As the applied current density increased, the crystallite sizes increased and their distribution got less uniform, and the microstrain and dislocation density decreased. The results of simulated pole figures obtained from Rietveld refinement illustrated that the texture of the coatings changed from no obvious texture to a strong [2 0 0] fiber texture with increasing applied current density. The texture evolution obtained from simulated pole figures was confirmed by the result of RTC and the measured pole figures. The evolutions of the microstructure and texture were derived from the change of the applied current density and incorporated Ti content in the Ni–Ti composite coatings.

  19. Mobility-electron density relation probed via controlled oxygen vacancy doping in epitaxial BaSnO3

    Directory of Open Access Journals (Sweden)

    Koustav Ganguly

    2017-05-01

    Full Text Available The recently discovered high room temperature mobility in wide band gap semiconducting BaSnO3 is of exceptional interest for perovskite oxide heterostructures. Critical open issues with epitaxial films include determination of the optimal dopant and understanding the mobility-electron density (μ-n relation. These are addressed here through a transport study of BaSnO3(001 films with oxygen vacancy doping controlled via variable temperature vacuum annealing. Room temperature n can be tuned from 5 × 1019 cm−3 to as low as 2 × 1017 cm−3, which is shown to drive a weak- to strong-localization transition, a 104-fold increase in resistivity, and a factor of 28 change in μ. The data reveal μ ∝ n0.65 scaling over the entire n range probed, important information for understanding mobility-limiting scattering mechanisms.

  20. An investigation of student understanding of classical ideas related to quantum mechanics: Potential energy diagrams and spatial probability density

    Science.gov (United States)

    Stephanik, Brian Michael

    This dissertation describes the results of two related investigations into introductory student understanding of ideas from classical physics that are key elements of quantum mechanics. One investigation probes the extent to which students are able to interpret and apply potential energy diagrams (i.e., graphs of potential energy versus position). The other probes the extent to which students are able to reason classically about probability and spatial probability density. The results of these investigations revealed significant conceptual and reasoning difficulties that students encounter with these topics. The findings guided the design of instructional materials to address the major problems. Results from post-instructional assessments are presented that illustrate the impact of the curricula on student learning.

  1. Low-Density Lipoprotein Receptor–Related Protein-1 Is a Therapeutic Target in Acute Myocardial Infarction

    Directory of Open Access Journals (Sweden)

    Stefano Toldo, PhD

    2017-10-01

    Full Text Available Low-density lipoprotein receptor–related protein-1 (LRP1 is a ubiquitous membrane receptor functioning as a scavenger and regulatory receptor, inducing anti-inflammatory and prosurvival signals. Based on the known structure–activity of the LRP1 receptor binding site, the authors synthesized a small peptide (SP16. SP16 induced a >50% reduction in infarct size (p < 0.001 and preservation of left ventricular systolic function (p < 0.001, and treatment with an LRP1 blocking antibody eliminated the protective effects of SP16. In conclusion, LRP1 activation with SP16 given within 30 min of reperfusion during experimental acute myocardial infarction leads to a cardioprotective signal reducing infarct size and preservation of cardiac systolic function.

  2. Sex-related differences in sleep slow wave activity in major depressive disorder: a high-density EEG investigation.

    Science.gov (United States)

    Plante, David T; Landsness, Eric C; Peterson, Michael J; Goldstein, Michael R; Riedner, Brady A; Wanger, Timothy; Guokas, Jeffrey J; Tononi, Giulio; Benca, Ruth M

    2012-09-18

    Sleep disturbance plays an important role in major depressive disorder (MDD). Prior investigations have demonstrated that slow wave activity (SWA) during sleep is altered in MDD; however, results have not been consistent across studies, which may be due in part to sex-related differences in SWA and/or limited spatial resolution of spectral analyses. This study sought to characterize SWA in MDD utilizing high-density electroencephalography (hdEEG) to examine the topography of SWA across the cortex in MDD, as well as sex-related variation in SWA topography in the disorder. All-night recordings with 256 channel hdEEG were collected in 30 unipolar MDD subjects (19 women) and 30 age and sex-matched control subjects. Spectral analyses of SWA were performed to determine group differences. SWA was compared between MDD and controls, including analyses stratified by sex, using statistical non-parametric mapping to correct for multiple comparisons of topographic data. As a group, MDD subjects demonstrated significant increases in all-night SWA primarily in bilateral prefrontal channels. When stratified by sex, MDD women demonstrated global increases in SWA relative to age-matched controls that were most consistent in bilateral prefrontal regions; however, MDD men showed no significant differences relative to age-matched controls. Further analyses demonstrated increased SWA in MDD women was most prominent in the first portion of the night. Women, but not men with MDD demonstrate significant increases in SWA in multiple cortical areas relative to control subjects. Further research is warranted to investigate the role of SWA in MDD, and to clarify how increased SWA in women with MDD is related to the pathophysiology of the disorder.

  3. Microstructure Modeling of Third Generation Disk Alloys

    Science.gov (United States)

    Jou, Herng-Jeng

    2010-01-01

    The objective of this program was to model, validate, and predict the precipitation microstructure evolution, using PrecipiCalc (QuesTek Innovations LLC) software, for 3rd generation Ni-based gas turbine disc superalloys during processing and service, with a set of logical and consistent experiments and characterizations. Furthermore, within this program, the originally research-oriented microstructure simulation tool was to be further improved and implemented to be a useful and user-friendly engineering tool. In this report, the key accomplishments achieved during the third year (2009) of the program are summarized. The activities of this year included: Further development of multistep precipitation simulation framework for gamma prime microstructure evolution during heat treatment; Calibration and validation of gamma prime microstructure modeling with supersolvus heat treated LSHR; Modeling of the microstructure evolution of the minor phases, particularly carbides, during isothermal aging, representing the long term microstructure stability during thermal exposure; and the implementation of software tools. During the research and development efforts to extend the precipitation microstructure modeling and prediction capability in this 3-year program, we identified a hurdle, related to slow gamma prime coarsening rate, with no satisfactory scientific explanation currently available. It is desirable to raise this issue to the Ni-based superalloys research community, with hope that in future there will be a mechanistic understanding and physics-based treatment to overcome the hurdle. In the mean time, an empirical correction factor was developed in this modeling effort to capture the experimental observations.

  4. Observation of asphalt binder microstructure with ESEM.

    Science.gov (United States)

    Mikhailenko, P; Kadhim, H; Baaj, H; Tighe, S

    2017-09-01

    The observation of asphalt binder with the environmental scanning electron microscope (ESEM) has shown the potential to observe asphalt binder microstructure and its evolution with binder aging. A procedure for the induction and identification of the microstructure in asphalt binder was established in this study and included sample preparation and observation parameters. A suitable heat-sampling asphalt binder sample preparation method was determined for the test and several stainless steel and Teflon sample moulds developed, finding that stainless steel was the preferable material. The magnification and ESEM settings conducive to observing the 3D microstructure were determined through a number of observations to be 1000×, although other magnifications could be considered. Both straight run binder (PG 58-28) and an air blown oxidised binder were analysed; their structures being compared for their relative size, abundance and other characteristics, showing a clear evolution in the fibril microstructure. The microstructure took longer to appear for the oxidised binder. It was confirmed that the fibril microstructure corresponded to actual characteristics in the asphalt binder. Additionally, a 'bee' micelle structure was found as a transitional structure in ESEM observation. The test methods in this study will be used for more comprehensive analysis of asphalt binder microstructure. © 2017 The Authors Journal of Microscopy © 2017 Royal Microscopical Society.

  5. Model for the evolution of network dislocation density in irradiated metals

    International Nuclear Information System (INIS)

    Garner, F.A.; Wolfer, W.G.

    1982-01-01

    It is a well-known fact that the total dislocation density that evolves in irradiated metals is a strong function of irradiation temperature. The dislocation density comprises two components, however, and only one of these (Frank loops) retains its temperature dependence at high fluence. The network dislocation density approaches a saturation level which is relatively insensitive to starting microstructure, stress, irradiation temperature, displacement rate and helium level. The latter statement is supported in this paper by a review of published microstructural data. A model has been developed to explain the insensitivity to many variables of the saturation network dislocation density in irradiated metals. This model also explains how the rate of approach to saturation can be sensitive to displacement rate and temperature while the saturation level itself is not dependent on temperature

  6. Microstructural characterization of EXCEL alloy

    International Nuclear Information System (INIS)

    Oroza Z E, Celiz; Saumell M, Lani; Versaci, R A; Bozzano, P B

    2012-01-01

    The microstructure of Excel alloy was studied by optical and scanning electron microscopy. X-ray diffraction was used to analyze the present phases. Characteristic peaks of α-Zr (HCP), β-Zr (BCC) and δhydride (FCC) were identified. The high relatives intensities of certain peaks suggest that samples are textured. Basal poles were dominant in radial-longitudinal planes and prismatic poles have the highest concentration in radial-tangential planes (author)

  7. Microstructures and properties of aluminum die casting alloys

    Energy Technology Data Exchange (ETDEWEB)

    M. M. Makhlouf; D. Apelian; L. Wang

    1998-10-01

    This document provides descriptions of the microstructure of different aluminum die casting alloys and to relate the various microstructures to the alloy chemistry. It relates the microstructures of the alloys to their main engineering properties such as ultimate tensile strength, yield strength, elongation, fatigue life, impact resistance, wear resistance, hardness, thermal conductivity and electrical conductivity. Finally, it serves as a reference source for aluminum die casting alloys.

  8. Fruit and vegetable purchasing and the relative density of healthy and unhealthy food stores: evidence from an Australian multilevel study.

    Science.gov (United States)

    Mason, Kate E; Bentley, Rebecca J; Kavanagh, Anne M

    2013-03-01

    Evidence of a relationship between residential retail food environments and diet-related outcomes is inconsistent. One reason for this may be that food environments are typically defined in terms of the absolute number of particular store types in an area, whereas a measure of the relative number of healthy and unhealthy stores may be more appropriate. Using cross-sectional data from the VicLANES study conducted in Melbourne, Australia, multilevel logistic regression analysis was used to estimate the independent associations between absolute measures (numbers of healthy and unhealthy stores) and a relative measure (relative density of healthy stores) of the food environment, and self-reported variety of fruit and vegetable purchasing in local households. Purchasing behaviour was measured as the odds of purchasing above the median level of fruit and vegetables. Compared to households in areas where healthy food stores made up no more than 10% of all healthy and unhealthy stores, households in areas with 10.1-15.0% healthy food stores and >15% healthy stores had increased odds of healthier purchasing (OR=1.48 (95% CI 1.12 to 1.96) and OR=1.45 (95% CI 1.09 to 1.91), respectively). There was less evidence of an association between absolute numbers of healthy or unhealthy stores and fruit and vegetable purchasing. We found strong evidence of healthier fruit and vegetable purchasing in households located in areas where the proportion of food stores that were healthy was greater. Policies aimed at improving the balance between healthy and unhealthy stores within areas may therefore be effective in promoting greater consumption of fruit and vegetables.

  9. High-Density Genetic Map Construction and Stem Total Polysaccharide Content-Related QTL Exploration for Chinese Endemic Dendrobium (Orchidaceae)

    Science.gov (United States)

    Lu, Jiangjie; Liu, Yuyang; Xu, Jing; Mei, Ziwei; Shi, Yujun; Liu, Pengli; He, Jianbo; Wang, Xiaotong; Meng, Yijun; Feng, Shangguo; Shen, Chenjia; Wang, Huizhong

    2018-01-01

    Plants of the Dendrobium genus are orchids with not only ornamental value but also high medicinal value. To understand the genetic basis of variations in active ingredients of the stem total polysaccharide contents (STPCs) among different Dendrobium species, it is of paramount importance to understand the mechanism of STPC formation and identify genes affecting its process at the whole genome level. Here, we report the first high-density single-nucleotide polymorphism (SNP) integrated genetic map with a good genome coverage of Dendrobium. The specific-locus amplified fragment sequencing (SLAF-seq) technology led to identification of 7,013,400 SNPs from 1,503,626 high-quality SLAF markers from two parents (Dendrobium moniliforme ♀ × Dendrobium officinale ♂) and their interspecific F1 hybrid population. The final genetic map contained 8, 573 SLAF markers, covering 19 linkage groups (LGs). This genetic map spanned a length of 2,737.49 cM, where the average distance between markers is 0.32 cM. In total, 5 quantitative trait loci (QTL) related to STPC were identified, 3 of which have candidate genes within the confidence intervals of these stable QTLs based on the D. officinale genome sequence. This study will build a foundation up for the mapping of other medicinal-related traits and provide an important reference for the molecular breeding of these Chinese herb. PMID:29636767

  10. Microstructural study of multiaxial low cycle fatigue

    Directory of Open Access Journals (Sweden)

    Masao Sakane

    2015-07-01

    Full Text Available This paper discusses the relationship between the stress response and the microstructure under tension-torsion multiaxial proportional and nonproportional loadings. Firstly, this paper discusses the material dependency of additional hardening of FCC materials in relation with the stacking fault energy of the materials. The FCC materials studied were Type 304 stainless steel, pure copper, pure nickel, pure aluminum and 6061 aluminum alloy. The material with lower stacking fault energy showed stronger additional hardening, which was discussed in relation with slip morphology and dislocation structures. This paper, next, discusses dislocation structures of Type 304 stainless steel under proportional and nonproportional loadings at high temperature. The relationship between the microstructure and the hardening behavior whether isotropic or anisotropic was discussed. The re-arrangeability of dislocation structure was discussed in loading mode change tests. Microstructures of the steel was discussed in more extensively programmed multiaxial low cycle fatigue tests at room temperature, where three microstructures, dislocation bundle, stacking fault and cells, which were discussed in relation with the stress response. Finally, temperature dependence of the microstructure was discussed under proportional and nonproportional loadings, by comparing the microstructures observed at room and high temperatures.

  11. Creep life assessment of Mod.9Cr-1Mo steel. Pt. 1. Quantitative evaluation of microstructural damage in creep rupture specimens

    International Nuclear Information System (INIS)

    Sawada, Kota; Maruyama, Kouichi; Komine, Ryuji; Nagae, Yuji

    1997-03-01

    Several microstructural changes take place in a material during the course of creep. These changes can be a measure of creep life consumption. In this paper, microstructural changes in Mod.9Cr-1Mo steel were studied in order to examine their ability as the measure of creep life consumption. Macroscopic structural changes, such as void growth, rotation of lath structure toward the tensile axis and elongation of grains, are evident only in the necked portion of ruptured specimens. These macroscopic structural changes are not useful for creep life assessment. Lath width increases and dislocation density within lath decreases with increasing creep duration. These changes in dislocation substructure start in the early stage of creep life, and cause the increase of strain rate in the tertiary creep stage. The lath width and the dislocation density reach a stationary value before rupture. The stationary values are independent of temperature, and uniquely related to creep stress normalized by shear modulus. The extent of these microstructural changes are greater at lower stresses under which the material is practically used. These facts suggest that the lath width and the dislocation density within lath can be a useful measure of creep life consumption. Hardness of crept specimens is closely related to the lath width and the dislocation density within lath. The changes of these microstructural features can be evaluated by the measurement of hardness. (author)

  12. AxTract: Toward microstructure informed tractography.

    Science.gov (United States)

    Girard, Gabriel; Daducci, Alessandro; Petit, Laurent; Thiran, Jean-Philippe; Whittingstall, Kevin; Deriche, Rachid; Wassermann, Demian; Descoteaux, Maxime

    2017-11-01

    Diffusion-weighted (DW) magnetic resonance imaging (MRI) tractography has become the tool of choice to probe the human brain's white matter in vivo. However, tractography algorithms produce a large number of erroneous streamlines (false positives), largely due to complex ambiguous tissue configurations. Moreover, the relationship between the resulting streamlines and the underlying white matter microstructure characteristics remains poorly understood. In this work, we introduce a new approach to simultaneously reconstruct white matter fascicles and characterize the apparent distribution of axon diameters within fascicles. To achieve this, our method, AxTract, takes full advantage of the recent development DW-MRI microstructure acquisition, modeling, and reconstruction techniques. This enables AxTract to separate parallel fascicles with different microstructure characteristics, hence reducing ambiguities in areas of complex tissue configuration. We report a decrease in the incidence of erroneous streamlines compared to the conventional deterministic tractography algorithms on simulated data. We also report an average increase in streamline density over 15 known fascicles of the 34 healthy subjects. Our results suggest that microstructure information improves tractography in crossing areas of the white matter. Moreover, AxTract provides additional microstructure information along the fascicle that can be studied alongside other streamline-based indices. Overall, AxTract provides the means to distinguish and follow white matter fascicles using their microstructure characteristics, bringing new insights into the white matter organization. This is a step forward in microstructure informed tractography, paving the way to a new generation of algorithms able to deal with intricate configurations of white matter fibers and providing quantitative brain connectivity analysis. Hum Brain Mapp 38:5485-5500, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

  13. SU-F-T-136: Breath Hold Lung Phantom Study in Using CT Density Versus Relative Stopping Power Ratio for Proton Pencil Beam Scanning System

    Energy Technology Data Exchange (ETDEWEB)

    Syh, J; Wu, H; Rosen, L [Willis-Knighton Medical Center, Shreveport, LA (United States)

    2016-06-15

    Purpose: To evaluate mass density effects of CT conversion table and its variation in current treatment planning system of spot scanning proton beam using an IROC proton lung phantom for this study. Methods: A proton lung phantom study was acquired to Imaging and Radiation Oncology Core Houston (IROC) Quality Assurance Center. Inside the lung phantom, GAF Chromic films and couples of thermal luminescent dosimeter (TLD) capsules embedded in specified PTV and adjacent structures to monitor delivered dosage and 3D dose distribution profiles. Various material such as cork (Lung), blue water (heart), Techron HPV (ribs) and organic material of balsa wood and cork as dosimetry inserts within phantom of solid water (soft tissue). Relative stopping power (RLSP) values were provided. Our treatment planning system (TPS) doesn’t require SP instead relative density was converted relative to water. However lung phantom was irradiated by planning with density override and the results were compared with IROC measurements. The second attempt was conducted without density override and compared with IROC’s. Results: The higher passing rate of imaging and measurement results of the lung phantom irradiation met the criteria by IROC without density override. The film at coronal plane was found to be shift due to inclined cylinder insertion. The converted CT density worked as expected to correlate relative stopping power. Conclusion: The proton lung phantom provided by IROC is a useful tool to qualify our commissioned proton pencil beam delivery with TPS within reliable confidence. The relative mass stopping power ratios of materials were converted from the relative physical density relative to water and the results were satisfied.

  14. Laboratory Density Functionals

    OpenAIRE

    Giraud, B. G.

    2007-01-01

    We compare several definitions of the density of a self-bound system, such as a nucleus, in relation with its center-of-mass zero-point motion. A trivial deconvolution relates the internal density to the density defined in the laboratory frame. This result is useful for the practical definition of density functionals.

  15. Spatial and temporal variation in proportional stock density and relative weight of smallmouth bass in a reservoir

    Science.gov (United States)

    Mesa, Matthew G.; Duke, S.D.; Ward, David L.

    1990-01-01

    Population data for smallmouth bass Micropterus dolomieui in 20,235 ha John Day Reservoir on the Columbia River were used to (1) determine whether Proportional Stock Density (PSD) and Relative Weight (Wr) varied spatially and temporally in two areas of the reservoir with established smallmouth bass fisheries; (2) explore possible causes of any observed variation; and (3) discuss some management implications and recommendations. Both PSD and Wr varied spatially and monthly in all years examined. On an annual basis, PSD varied at one area but not at the other, whereas Wr showed little variation. Possible explanations for the variation in PSD and Wr are differences in growth, mortality, recruitment, and exploitation. Our data suggested that regulations established or changed on a reservoir-wide basis may have different effects on the fishery, depending on location in the reservoir. Also, pooling data from various areas within a reservoir to yield point estimates of structural indices may not represent the variation present in the population as a whole. The significant temporal variability reflects the importance of determining the proper time to sample fish to yield representative estimates of the variable of interest. In areas with valuable fisheries or markedly different population structures, we suggest that an area-specific approach be made to reservoir fishery management, and that efforts be made toward effecting consistent harvest regulations in interstate waters.

  16. Work- and travel-related physical activity and alcohol consumption: relationship with bone mineral density and calcaneal quantitative ultrasonometry.

    Science.gov (United States)

    Sritara, Chanika; Thakkinstian, Ammarin; Ongphiphadhanakul, Boonsong; Pornsuriyasak, Prapaporn; Warodomwichit, Daruneewan; Akrawichien, Tawatchai; Vathesatogkit, Prin; Sritara, Piyamitr

    2015-01-01

    A number of healthy workers rarely exercise because of a lack of time or resources. Physical activity related to work and everyday travel may be more feasible, but evidence of its beneficial effect on bone health is scarce. We assessed if this form of physical activity was associated with higher bone mineral density (BMD) and stiffness index (SI) when adjusted for recreational physical activity, age, body mass index, smoking, alcohol consumption, education, and serum level of 25-hydroxyvitamin D. Healthy workers, aged 25-54 yr, of the Electricity Generating Authority of Thailand were surveyed. The outcomes were BMD (lumbar spine, femoral neck, and total hip) and calcaneal SI. Physical activity was estimated using the global physical activity questionnaire and considered active when >600 metabolic equivalent tasks (min). Of 2268 subjects, 74% were men. Active male subjects had significantly higher BMD at the femoral neck and total hip (pwomen (p>0.05). In men, work and travel physical activity seems beneficial to male bone health; hence, it should be encouraged. Furthermore, smoking appeared harmful while moderate alcohol consumption was beneficial. Copyright © 2015 The International Society for Clinical Densitometry. Published by Elsevier Inc. All rights reserved.

  17. Seasonal dynamics in the relative density of aquatic flora along some coastal areas of the Red Sea, Tabuk, Saudi Arabia

    Directory of Open Access Journals (Sweden)

    Abid Ali Ansari

    2016-09-01

    Full Text Available Plants are the producers of all autotrophic ecosystems’ and are the base of the food chain taking energy from the sun and converting it into food for all other organisms through photosynthesis. Plants grow in certain places and seasons when the environmental factors are suitable for their germination, growth and developments that influence their diversity. Environmental factors can include abiotic factors such as temperature, light, moisture, soil nutrients; or biotic factors like competition from other plants or grazing by animals. Anthropogenic perturbations can also influence distribution patterns. Monitoring of ecological habitats and diversity of some aquatic flora along some coastal areas of Red Sea has been done to understand the dynamics of aquatic plants influenced by prevailing environmental and anthropogenic perturbations The results of this research showed that the summer season is the most suitable period for the study of aquatic plant diversity along the coastal sites of Red Sea. The aquatic flora had high relative density and diversity in April, May, June and July and these four months of the summer season are best for collection of aquatic plants from the selected coastal areas of Red Sea for medicinal purposes and ecological studies.

  18. Non-iterative determination of the stress-density relation from ramp wave data through a window

    Science.gov (United States)

    Dowling, Evan; Fratanduono, Dayne; Swift, Damian

    2017-06-01

    In the canonical ramp compression experiment, a smoothly-increasing load is applied the surface of the sample, and the particle velocity history is measured at interfaces two or more different distances into the sample. The velocity histories are used to deduce a stress-density relation by correcting for perturbations caused by reflected release waves, usually via the iterative Lagrangian analysis technique of Rothman and Maw. We previously described a non-iterative (recursive) method of analysis, which was more stable and orders of magnitude faster than iteration, but was subject to the limitation that the free surface velocity had to be sampled at uniform intervals. We have now developed more general recursive algorithms suitable for analyzing ramp data through a finite-impedance window. Free surfaces can be treated seamlessly, and the need for uniform velocity sampling has been removed. These calculations require interpolation of partially-released states using the partially-constructed isentrope, making them slower than the previous free-surface scheme, but they are still much faster than iterative analysis. This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

  19. Innovative microstructures in nuclear fuels

    International Nuclear Information System (INIS)

    Kutty, T.R.G.; Kumar, Arun; Kamath, H.S.

    2009-01-01

    For cleaner and safe nuclear power, new processes are required to design better nuclear fuels and make more efficient reactors to generate nuclear power. Therefore, one must understand how the microstructure changes during reactor operation. Accordingly, the materials scientists and engineers can then design and fabricate fuels with higher reliability and performance. Microstructure and its evolution are big unknowns in nuclear fuel. The basic requirements for the high performance of a fuel are: a) Soft pellets - To reduce Pellet clad mechanical interaction (PCMI) b) Large grain size - To reduce fission gas release (FGR). The strength of the pellet at room temperature is related to grain size by the Hall-Petch relation. Accordingly, the lower grain sized pellets will have high strength. But at high temperature (above equicohesive temperature) the grain boundaries becomes weaker than grain matrix. Since the small grain sized pellets have more grain boundary areas, these pellet become softer than pellet that have large grain sizes. Also as grain size decreases, creep rate of the fuel increases. Therefore, pellets with small grain size have higher creep rate and better plasticity. Therefore, these pellets will be useful to reduce the PCMI. On the other hand, pellet with large grain size is beneficial to reduce the fission gas release. In developing thermal reactor fuels for high burn-up, this factor should be taken into consideration. The question being asked is whether the microstructure can be tailored for irradiation hardening, fracture resistance, fission-gas release. This paper deals with the role played by microstructure for better irradiation performance. (author)

  20. Vertical Distribution of Soil Organic Carbon Density in Relation to Land Use/Cover, Altitude and Slope Aspect in the Eastern Himalayas

    Directory of Open Access Journals (Sweden)

    Tshering Dorji

    2014-10-01

    Full Text Available In-depth understanding about the vertical distribution of soil organic carbon (SOC density is crucial for carbon (C accounting, C budgeting and designing appropriate C sequestration strategies. We examined the vertical distribution of SOC density under different land use/land cover (LULC types, altitudinal zones and aspect directions in a montane ecosystem of Bhutan. Sampling sites were located using conditioned Latin hypercube sampling (cLHS scheme. Soils were sampled based on genetic horizons. An equal-area spline function was fitted to interpolate the target values to predetermined depths. Linear mixed model was fitted followed by mean separation tests. The results show some significant effects of LULC, altitudinal zone and slope aspect on the vertical distribution of SOC density in the profiles. Based on the proportion of mean SOC density in the first 20 cm relative to the cumulative mean SOC density in the top meter, the SOC density under agricultural lands (34% was more homogeneously distributed down the profiles than forests (39%, grasslands (59% and shrublands (43%. Similarly, the SOC density under 3500–4000 m zone (35% was more uniformly distributed compared to 3000–3500 m zone (43% and 1769–2500 m and 2500–3000 m zones (41% each. Under different aspect directions, the north and east-facing slopes (38% each had more uniform distribution of SOC density than south (40% and west-facing slopes (49%.

  1. Relations microstructure - magnetic properties - squareness factor of PrFeB and NdFeB sintered magnets prepared with hydrogen

    International Nuclear Information System (INIS)

    Perigo, Elio Alberto

    2009-01-01

    In this work, it has firstly been evaluated the preparation of Pr 16 Fe 76 B 8 sintered permanent magnets (% at.) by means of high-energy milling using a planetary ball mill. The influence of both milling speed and time has been verified. The best magnetic properties [J R = (1.02 ± 0.02) T, μ 0J H c = (1.42 ± 0.03) T and (BH) max = (200 ± 4) kJm -3 ] have been found for a permanent magnet prepared with the magnetic alloy milled during 75 minutes using a rotational milling speed of 200 rpm. In order to improve the remanence, the hydrogen decrepitation process time has been reduced from 60 minutes to 2 minutes. In this case, it has been obtained a sintered magnet with J R = (1.14 ± 0.02) T, μ 0J H c = (1.44 ± 0.03) T and (BH) max = (250 ± 5) kJm -3 due to the improvement of crystallographic alignment of the hard magnetic phase. During such investigation, a new methodology to quantify the parameter has been developed. Subsequently, for the first time, a quantitative correlation between the microstructure and the squareness factor in anisotropic sintered RE 16 Fe 76 B 8 (RE = Nd or Pr) magnets has been proposed. The presented expression utilizes the mean size, the mean elongation and the mean roundness of the hard magnetic grains as well as their respective standard deviations. The squareness factor can be improved with a microstructure with rounder grains and with a sharp grain size distribution. The grain size homogeneity is more important to enhance the squareness factor compared to grain shape homogeneity. Furthermore, it has also been verified that the annealing after sintering improves the grain shape homogeneity and the milling enhances the grain size homogeneity. Moreover, the effect of the temperature on the squareness factor of anisotropic sintered magnets has also been evaluated. Such parameter is mainly controlled by the sample's microstructure, in agreement with the proposed expression. Furthermore, a quantitative correlation between the maximum

  2. Microstructure Reconstruction of Sheet Molding Composite Using a Random Chips Packing Algorithm

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Tianyu; Xu, Hongyi; Chen, Wei

    2017-04-06

    Fiber-reinforced polymer composites are strong candidates for structural materials to replace steel and light alloys in lightweight vehicle design because of their low density and relatively high strength. In the integrated computational materials engineering (ICME) development of carbon fiber composites, microstructure reconstruction algorithms are needed to generate material microstructure representative volume element (RVE) based on the material processing information. The microstructure RVE reconstruction enables the material property prediction by finite element analysis (FEA)This paper presents an algorithm to reconstruct the microstructure of a chopped carbon fiber/epoxy laminate material system produced by compression molding, normally known as sheet molding compounds (SMC). The algorithm takes the result from material’s manufacturing process as inputs, such as the orientation tensor of fibers, the chopped fiber sheet geometry, and the fiber volume fraction. The chopped fiber sheets are treated as deformable rectangle chips and a random packing algorithm is developed to pack these chips into a square plate. The RVE is built in a layer-by-layer fashion until the desired number of lamina is reached, then a fine tuning process is applied to finalize the reconstruction. Compared to the previous methods, this new approach has the ability to model bended fibers by allowing limited amount of overlaps of rectangle chips. Furthermore, the method does not need SMC microstructure images, for which the image-based characterization techniques have not been mature enough, as inputs. Case studies are performed and the results show that the statistics of the reconstructed microstructures generated by the algorithm matches well with the target input parameters from processing.

  3. The three-dimensional microstructure of polycrystalline materials unravelled by synchrotron light; La microstructure 3D des materiaux polycristallins vue sous la lumiere synchrotron

    Energy Technology Data Exchange (ETDEWEB)

    Ludwig, W.; Herbig, M. [Universite de Lyon, INSA-Lyon, MATEIS, UMR 5510 CNRS, LyonTech Campus, Bat. Saint-Exupery, 25 avenue Jean Capelle, F-69621 Villeurbanne Cedex (France); Ludwig, W.; King, A; Reischig, P. [European Synchrotron Radiation Facility, 6 rue J. Horowitz, BP 220, F-38043 Grenoble (France); Marrow, J. [University of Oxford, Department of Materiels, Parks road, Oxford OX1 3PH (United Kingdom); Babout, L. [Computer Engineering Department, Technical University of Lodz, ul. Stefanowskiego 18/22, PL-90- 537 Lodz (Poland); Mejdal Lauridsen, E. [Materials Research Department, Riso National Laboratory for Sustainable Energy, Technical University of Denmark (DTU), Building 228, PO Box 49, DK-4000 Roskilde (Denmark); Proudhon, H. [MINES ParisTech, Centre des Materiaux, UMR 7633 CNRS, BP 87, F-91003 Evry Cedex (France)

    2011-07-01

    Synchrotron radiation X-ray imaging and diffraction techniques offer new possibilities for non-destructive bulk characterization of polycrystalline materials. Minute changes in electron density (different crystallographic phases, cracks, porosities) can be detected using 3D imaging modes exploiting Fresnel diffraction and the coherence properties of third generation synchrotron beams. X-ray diffraction contrast tomography, a technique based on Bragg diffraction imaging, provides access to the 3D shape, orientation and elastic strain state of the individual grains from polycrystalline sample volumes containing several hundred up to a few thousand grains. Combining both imaging modalities allows a comprehensive description of the microstructure of the material at the micrometer length scale. Repeated observations during (interrupted) mechanical tests provide unprecedented insight into crystallographic and grain microstructure related aspects of polycrystal deformation and degradation mechanisms in materials, fulfilling some conditions on grain size and deformation state. (authors)

  4. A Markov random field approach for microstructure synthesis

    International Nuclear Information System (INIS)

    Kumar, A; Nguyen, L; DeGraef, M; Sundararaghavan, V

    2016-01-01

    We test the notion that many microstructures have an underlying stationary probability distribution. The stationary probability distribution is ubiquitous: we know that different windows taken from a polycrystalline microstructure are generally ‘statistically similar’. To enable computation of such a probability distribution, microstructures are represented in the form of undirected probabilistic graphs called Markov Random Fields (MRFs). In the model, pixels take up integer or vector states and interact with multiple neighbors over a window. Using this lattice structure, algorithms are developed to sample the conditional probability density for the state of each pixel given the known states of its neighboring pixels. The sampling is performed using reference experimental images. 2D microstructures are artificially synthesized using the sampled probabilities. Statistical features such as grain size distribution and autocorrelation functions closely match with those of the experimental images. The mechanical properties of the synthesized microstructures were computed using the finite element method and were also found to match the experimental values. (paper)

  5. Continuous media with microstructure

    CERN Document Server

    2010-01-01

    This book discusses the extension of classical continuum models. To the first class addressed belong various thermodynamic models of multicomponent systems, and to the second class belong primarily microstructures created by phase transformations.

  6. Optics of dielectric microstructures

    DEFF Research Database (Denmark)

    Søndergaard, Thomas

    2002-01-01

    From the work carried out within the ph.d. project two topics have been selected for this thesis, namely emission of radiation by sources in dielectric microstructures, and planar photonic crystal waveguides. The work done within the first topic, emission of radiation by sources in dielectric...... microstructures, will be presented in the part I of this thesis consisting of the chapters 2-5. An introductions is given in chapter 2. In part I three methods are presented for calculating spontaneous and classical emission from sources in dielectric microstructures. The first method presented in chapter 3...... is based on the Fermi Golden Rule, and spontaneous emission from emitters in a passive dielectric microstructure is calculated by summing over the emission into each electromagnetic mode of the radiation field. This method is applied to investigate spontaneous emission in a two-dimensional photonic crystal...

  7. Diagnostic study of low-pressure Ar-O2 remote plasma generated in HCD-L 300 system: Relative density of O atom

    International Nuclear Information System (INIS)

    Saloum, S.; Naddaf, M.

    2007-01-01

    The relative density of O atom of Ar-O 2 remote plasma excited in a low pressure 13.56 HMz hollow cathode discharge system has been investigated. The measurements were carried out at a total pressure of 0.05 mbar, radiofrequency (RF) power of 200 W and at three different axial distances in the plasma chamber below the outlet of the discharge source. Using optical emission spectroscopy (OES), the relative density of O ground state was determined from intensity ratio of O(844.6 nm) and Ar(750.4 nm) lines. The electron temperature and O 2 + densities have been measured using double langmuir probe measurements. The kinetic study of Ar-O 2 plasma, combined with both spectroscopy and langmuir probe measurements, revealed that the main production mechanism of the excited O(3p 3 P) is direct excitation by electron impact. A maximum of O ground state relative density and correspondingly a minimum of O 2 + density are obtained for the ratio O 2 /Ar: 60/40. The maximum O density in the remote zone is found to be 4.5 times higher than at the outlet of source. (author)

  8. Zirconium microstructures: uncharted possibilities

    International Nuclear Information System (INIS)

    Samajdar, I.; Kumar, Gulshan; Singh, Jaiveer; Lodh, Arijit; Srivastava, D.; Tewari, R.; Dey, G.K.; Saibaba, N.

    2015-01-01

    The 'conventional' Zirconium microstructures can be significantly extended with information on: (i) microtexture, (ii) residual stresses and (iii) local mechanical properties. Though these involve different tools, but a consolidated microstructure can be crated. This is the theme of this presentation. Examples of this consolidated picture will be made from deformation twinning, recovery-recrystallization, burst ductility and orientation versus solid solution hardening. (author)

  9. Superlattice Microstructured Optical Fiber

    Science.gov (United States)

    Tse, Ming-Leung Vincent; Liu, Zhengyong; Cho, Lok-Hin; Lu, Chao; Wai, Ping-Kong Alex; Tam, Hwa-Yaw

    2014-01-01

    A generic three-stage stack-and-draw method is demonstrated for the fabrication of complex-microstructured optical fibers. We report the fabrication and characterization of a silica superlattice microstructured fiber with more than 800 rhomboidally arranged air-holes. A polarization-maintaining fiber with a birefringence of 8.5 × 10−4 is demonstrated. The birefringent property of the fiber is found to be highly insensitive to external environmental effects, such as pressure. PMID:28788693

  10. Imaging brain tumour microstructure.

    Science.gov (United States)

    Nilsson, Markus; Englund, Elisabet; Szczepankiewicz, Filip; van Westen, Danielle; Sundgren, Pia C

    2018-05-08

    Imaging is an indispensable tool for brain tumour diagnosis, surgical planning, and follow-up. Definite diagnosis, however, often demands histopathological analysis of microscopic features of tissue samples, which have to be obtained by invasive means. A non-invasive alternative may be to probe corresponding microscopic tissue characteristics by MRI, or so called 'microstructure imaging'. The promise of microstructure imaging is one of 'virtual biopsy' with the goal to offset the need for invasive procedures in favour of imaging that can guide pre-surgical planning and can be repeated longitudinally to monitor and predict treatment response. The exploration of such methods is motivated by the striking link between parameters from MRI and tumour histology, for example the correlation between the apparent diffusion coefficient and cellularity. Recent microstructure imaging techniques probe even more subtle and specific features, providing parameters associated to cell shape, size, permeability, and volume distributions. However, the range of scenarios in which these techniques provide reliable imaging biomarkers that can be used to test medical hypotheses or support clinical decisions is yet unknown. Accurate microstructure imaging may moreover require acquisitions that go beyond conventional data acquisition strategies. This review covers a wide range of candidate microstructure imaging methods based on diffusion MRI and relaxometry, and explores advantages, challenges, and potential pitfalls in brain tumour microstructure imaging. Copyright © 2018. Published by Elsevier Inc.

  11. Localization of oxidized low-density lipoprotein and its relation to plaque morphology in human coronary artery.

    Directory of Open Access Journals (Sweden)

    Yasumi Uchida

    Full Text Available OBJECTIVES: Oxidized low-density lipoprotein (oxLDL plays a key role in the formation of atherosclerotic plaques. However, its localization in human coronary arterial wall is not well understood. The present study was performed to visualize deposition sites and patterns of native oxLDL and their relation to plaque morphology in human coronary artery. METHODS: Evans blue dye (EB elicits a violet fluorescence by excitation at 345-nm and emission at 420-nm, and a reddish-brown fluorescence by excitation at 470-nm and emission at 515-nm characteristic of oxLDL only. Therefore, native oxLDL in excised human coronary artery were investigated by color fluorescent microscopy (CFM using EB as a biomarker. RESULTS: (1 By luminal surface scan with CFM, the % incidence of oxLDL in 38 normal segments, 41 white plaques and 32 yellow plaques that were classified by conventional angioscopy, was respectively 26, 44 and 94, indicating significantly (p<0.05 higher incidence in the latter than the former two groups. Distribution pattern was classified as patchy, diffuse and web-like. Web-like pattern was observed only in yellow plaques with necrotic core. (2 By transected surface scan, oxLDL deposited within superficial layer in normal segments and diffusely within both superficial and deep layers in white and yellow plaques. In yellow plaques with necrotic core, oxLDL deposited not only in the marginal zone of the necrotic core but also in the fibrous cap. CONCLUSION: Taken into consideration of the well-known process of coronary plaque growth, the results suggest that oxLDL begins to deposit in human coronary artery wall before plaque formation and increasingly deposits with plaque growth, exhibiting different deposition sites and patterns depending on morphological changes.

  12. The low-density lipoprotein receptor-related protein 1 and amyloid-β clearance in Alzheimer’s disease

    Directory of Open Access Journals (Sweden)

    Takahisa eKanekiyo

    2014-05-01

    Full Text Available Accumulation and aggregation of amyloid-β (Aβ peptides in the brain trigger the development of progressive neurodegeneration and dementia associated with Alzheimer’s disease (AD. Perturbation in Aβ clearance, rather than Aβ production, is likely the cause of sporadic, late-onset AD, which accounts for the majority of AD cases. Since cellular uptake and subsequent degradation constitute a major Aβ clearance pathway, the receptor-mediated endocytosis of Aβ has been intensely investigated. Among Aβ receptors, the low-density lipoprotein receptor-related protein 1 (LRP1 is one of the most studied receptors. LRP1 is a large endocytic receptor for more than 40 ligands, including apolipoprotein E (apoE, α2-macroglobulin and Aβ. Emerging in vitro and in vivo evidence demonstrates that LRP1 is critically involved in brain Aβ clearance. LRP1 is highly expressed in a variety of cell types in the brain including neurons, vascular cells and glial cells, where LRP1 functions to maintain brain homeostasis and control Aβ metabolism. LRP1-mediated endocytosis regulates cellular Aβ uptake by binding to Aβ either directly or indirectly through its co-receptors or ligands. Furthermore, LRP1 regulates several signaling pathways, which also likely influences Aβ endocytic pathways. In this review, we discuss how LRP1 regulates the brain Aβ clearance and how this unique endocytic receptor participates in AD pathogenesis. Understanding of the mechanisms underlying LRP1-mediated Aβ clearance should enable the rational design of novel diagnostic and therapeutic strategies for AD.

  13. Microstructure and mechanical properties of bulk highly faulted fcc/hcp nanostructured cobalt microstructures

    Energy Technology Data Exchange (ETDEWEB)

    Barry, Aliou Hamady [Université Paris 13, Sorbonne Paris Cité, LSPM CNRS UPR 3407, 93430 Villetaneuse (France); Laboratoire Chimie des Matériaux, Département de Chimie, Faculté des Sciences et Technique, Université de Nouakchott (Mauritania, Islamic Republic of); Dirras, Guy, E-mail: dirras@unv-paris13.fr [Université Paris 13, Sorbonne Paris Cité, LSPM CNRS UPR 3407, 93430 Villetaneuse (France); Schoenstein, Frederic; Tétard, Florent; Jouini, Noureddine [Université Paris 13, Sorbonne Paris Cité, LSPM CNRS UPR 3407, 93430 Villetaneuse (France)

    2014-05-01

    Nanostructured cobalt powders with an average particle size of 50 nm were synthesized using a polyol method and subsequently consolidated by spark plasma sintering (SPS). SPS experiments performed at 650 °C with sintering times ranging from 5 to 45 min under a pressure of 100 MPa, yielded to dense bulk nanostructured cobalt (relative density greater than 97%). X-ray diffraction patterns of the as-prepared powders showed only a face centered cubic (fcc) crystalline phase, whereas the consolidated samples exhibited a mixture of both fcc and hexagonal close packed (hcp) phases. Transmission electron microscopy observations revealed a lamellar substructure with a high density of nanotwins and stacking faults in every grain of the sintered samples. Room temperature compression tests, carried out at a strain rate of 10{sup −3} s{sup −1}, yielded to highest strain to fracture values of up to 5% for sample of holding time of 15 min, which exhibited a yield strength of 1440 MPa, an ultimate strength as high as 1740 MPa and a Young's modulus of 205 GPa. The modulus of elasticity obtained from the nanoindentation tests, ranges from 181 to 218 GPa. The lowest modulus value of 181 GPa was obtained for the sample with the highest sintering time (45 min), which could be related to mass density loss as a consequence of trapped gases releasing. - Highlights: • Co nanopowder (50 nm) was prepared by reduction in polyol medium. • SPS was used to process bulk nanostructured Co specimens. • Microstructures were made of intricate fcc/hcp, along with nanotwins and SFs. • High strengths and moderate compressive ductility were obtained. • Deformation mechanisms related to complex interplay of different length scales.

  14. Microstructure, consolidation and mechanical behaviour of Mg/n-TiC composite

    Directory of Open Access Journals (Sweden)

    N. Vijay Ponraj

    2016-09-01

    Full Text Available In this work, the microstructure, consolidation and mechanical properties of pure magnesium, magnesium based composite containing with different fractions (5, 10, 15 wt% of Titanium carbide nanoparticles (n-TiC were fabricated via powder metallurgy technique. The fabricated composites exhibited homogeneous distribution of TiC with little porosity. Microstructure of the composite and powders was studied using X-ray diffraction, Scanning electron microscope, and Transmission electron microscope. Microstructural characterization of the materials exposed that the accumulation of nanosized titanium carbide reinforcement enhanced the homogenization during mechanical blending. The relative density, compressibility, green compressive strength, sinterability and hardness of the nanocomposites were also examined. The effect of reinforcement on the densification was studied and reported in terms of the relative density and consolidation behaviour of the Magnesium matrix with n-TiC was studied and best compacted fit obtained through the Heckel, Panelli Ambrosio Filho and Ge equations. The compressive strength of the composite significantly increases from 230 MPa to 389 MPa with content of n-TiC and sintering temperature. Experiments have been performed under different conditions of temperature, n-TiC Content, and compacting pressure.

  15. Microstructure of Tablet-Pharmaceutical Significance, Assessment, and Engineering.

    Science.gov (United States)

    Sun, Changquan Calvin

    2017-05-01

    To summarize the microstructure - property relationship of pharmaceutical tablets and approaches to improve tablet properties through tablet microstructure engineering. The main topics reviewed here include: 1) influence of material properties and manufacturing process parameters on the evolution of tablet microstructure; 2) impact of tablet structure on tablet properties; 3) assessment of tablet microstructure; 4) development and engineering of tablet microstructure. Microstructure plays a decisive role on important pharmaceutical properties of a tablet, such as disintegration, drug release, and mechanical strength. Useful information on mechanical properties of a powder can be obtained from analyzing tablet porosity-pressure data. When helium pycnometry fails to accurately measure true density of a water-containing powder, non-linear regression of tablet density-pressure data is a useful alternative method. A component that is more uniformly distributed in a tablet generally exerts more influence on the overall tablet properties. During formulation development, it is highly recommended to examine the relationship between any property of interest and tablet porosity when possible. Tablet microstructure can be engineered by judicious selection of formulation composition, including the use of the optimum solid form of the drug and appropriate type and amount of excipients, and controlling manufacturing process.

  16. [Correlative factors related to the density of Meriones unguiculatus in the Meriones unguiculatus plague foci of Hebei province, 2001-2013].

    Science.gov (United States)

    Niu, Y F; Kang, X P; Yan, D; Zhang, Y H; Liu, G; Kang, D M; Liu, H Z; Shi, X M; Li, Y G

    2016-08-10

    To explore the yearly, monthly and habitat-related distribution and their relations with Meriones unguiculatus density in the Hebei Meriones unguiculatus plague foci, from 2001 to 2013. Data related to Meriones unguiculatus was gathered through the monitoring programs set up at the national and provincial Meriones unguiculatus plague foci in Hebei province, from 2001 to 2013. According to the yearly density of Meriones unguiculatus, criteria set for the three groups under study, were as follows:'high-risk group'-when the rodent density was≥1.00 under rodents/hm(2),'warning group'-when the rodents/hm(2)>rodent density> 0.20,'standard group'-when rodents/hm(2) rodent density≤0.20 rodents/hm(2). Differences of habitats and monthly distribution among the three groups were compared, under the Kruskal-Wallis H rank sum test while their relations were under the multiple correspondence analysis. The Meriones unguiculatus densities were higher than 1.00 rodents/hm(2), far above the set national standards, in the monitoring area, between 2001 and 2005. From 2005, though the rodent densities began to decrease, however, figures from 2008 to 2013 were still among 0.20 to 1.00 rodents/hm(2). The distribution of habitats in the three groups showed that the Meriones unguiculatus densities were all different in habitats and the difference was statistically significant (Pplague increased in Hebei Meriones unguiculatus plague foci. Based on the distribution of Meriones unguiculatus, programs should be set to monitor the rodent in arable land and wasteland, in April and June, to reduce the prevalence of animals plague.

  17. Optical fabrication of large area photonic microstructures by spliced lens

    Science.gov (United States)

    Jin, Wentao; Song, Meng; Zhang, Xuehua; Yin, Li; Li, Hong; Li, Lin

    2018-05-01

    We experimentally demonstrate a convenient approach to fabricate large area photorefractive photonic microstructures by a spliced lens device. Large area two-dimensional photonic microstructures are optically induced inside an iron-doped lithium niobate crystal. The experimental setups of our method are relatively compact and stable without complex alignment devices. It can be operated in almost any optical laboratories. We analyze the induced triangular lattice microstructures by plane wave guiding, far-field diffraction pattern imaging and Brillouin-zone spectroscopy. By designing the spliced lens appropriately, the method can be easily extended to fabricate other complex large area photonic microstructures, such as quasicrystal microstructures. Induced photonic microstructures can be fixed or erased and re-recorded in the photorefractive crystal.

  18. Relationships between microstructure and microfissuring in alloy 718

    Science.gov (United States)

    Thompson, R. G.

    1985-01-01

    Microfissures which occur in the weld heat affected zone of alloy 718 can be a limiting factor in the material's weldability. Several studies have attempted to relate microfissuring susceptibility to processing conditions, microstructure, and/or heat-to-heat chemistry differences. The present investigation studies the relationships between microstructure and microfissuring by isolating a particular microstructural feature and measuring microfissuring as a function of that feature. Results to date include the identification of a microstructure-microfissure sequence, microfissuring susceptibility as a function of grain size, and microfissuring susceptibility as a function of solution annealing time.

  19. Composite microstructural anisotropies in reservoir rocks: consequences on elastic properties and relation with deformation; Anisotropies microstructurales composites dans les roches reservoir: consequences sur les proprietes elastiques et relation a la deformation

    Energy Technology Data Exchange (ETDEWEB)

    Louis, L.

    2003-10-15

    From diagenesis to tectonic stress induced deformation, rock microstructures always present some anisotropy associated with a preferential orientation, shape or spatial arrangement of its constituents. Considering the consequences anisotropy has on directional transport properties and compliance, as the geological history it carries, this approach has received a particular attention in numerous works. In this work, the microstructural features of various sedimentary rocks were investigated through direct observations and laboratory measurements in naturally deformed and undeformed blocks, samples being considered as effective media. All investigated samples were found to be anisotropic with respect to the physical properties we measured (i.e. ultrasonic P-wave velocity, magnetic susceptibility, electrical conductivity). Considering that P-wave velocities can be described by a second order tensor, we applied to the velocity data the same inversion procedure as the one routinely used in magnetic studies, which provided an efficient tool to estimate and compare these 3D anisotropies with respect to the original sample geographical position. In each case, we tried to identify as thoroughly as possible the microstructural source of the observed anisotropies, first by the mean of existing models, then through direct observations (optic and electronic microscopy). Depending on the rock investigated, anisotropy was found to be controlled by pore shape, intergranular contact distribution, preferentially oriented microcracks interacting with compaction pattern or pressure solution cleavages interacting with each other. The net result of this work is that P-wave velocity anisotropy can express the interaction between different microstructural features as well as their evolution during deformation. (author)

  20. Microstructure, Properties and Atomic Level Strain in Severely Deformed Rare Metal Niobium

    Directory of Open Access Journals (Sweden)

    Lembit KOMMEL

    2012-12-01

    Full Text Available The mechanical and physical properties relationship from atomic level strain/stress causes dislocation density and electrical conductivity relationship, as well as crystallites deformation and hkl-parameter change in the severely deformed pure refractory rare metal Nb at ambient temperature and during short processing times. The above mentioned issues are discussed in this study. For ultrafine-grained and nanocrystalline microstructure forming in metal the equal-channel angular pressing and hard cyclic viscoplastic deformation were used. The flat deformation and heat treatment at different parameters were conducted as follows. The focused ion beam method was used for micrometric measures samples manufacturied under nanocrystalline microstructure study by transmission electron microscope. The microstructure features of metal were studied under different orientations by X-ray diffraction scattering method, and according to the atomic level strains, dislocation density, hkl-parameters and crystallite sizes were calculated by different computation methods. According to results the evolutions of atomic level strains/stresses, induced by processing features have great influence on the microstructure and advanced properties forming in pure Nb. Due to cumulative strain increase the tensile stress and hardness were increased significantly. In this case the dislocation density of Nb varies from 5.0E+10 cm–2 to 2.0E+11 cm–2. The samples from Nb at maximal atomic level strain in the (110 and (211 directions have the maximal values of hkl-parameters, highest tensile strength and hardness but minimal electrical conductivity. The crystallite size was minimal and relative atomic level strain maximal in (211 orientation of crystal. Next, flat deformation and heat treatment increase the atomic level parameters of severely deformed metal.DOI: http://dx.doi.org/10.5755/j01.ms.18.4.3091

  1. Microstructure evolution and microstructure/mechanical properties relationships in alpha+beta titanium alloys

    Science.gov (United States)

    Lee, Eunha

    In this study, the microstructural evolution of Timetal 550 was investigated. Timetal 550 showed two types of phase transformations (martensitic and nucleation and growth) depending on the cooling rate from the beta region. The alpha phase initially precipitated at the prior beta grain boundaries, and it had a Burgers OR with one of the adjacent grains. It was found that colonies could grow, even in the fast-cooled Timetal 550 sample, from the grain boundary alpha into the prior beta grain with which it exhibited the Burgers OR. Three orientation relationships were also found between alpha laths in the basketweave microstructure. Microhardness testing demonstrated that fast-cooled Timetal 550 samples with basketweave microstructure were harder than slowly-cooled samples with colony microstructure. Orientation-dependent deformation was found in the colony microstructure. Specifically, when the surface normal is perpendicular to the [0001] of alpha, the material deforms easily in the direction perpendicular to the [0001] of alpha. Fuzzy logic and Bayesian neural network models were developed to predict the room temperature tensile properties of Timetal 550. This involved the development of a database relating microstructural features to mechanical properties. A Gleeble 3800 thermal-mechanical simulator was used to develop various microstructures. Microstructural features of tensile-tested samples were quantified using stereological procedures. The quantified microstructural features and the tensile properties were used as inputs and outputs, respectively, for modeling the relationships between them. The individual influence of five microstructural features on tensile properties was determined using the established models. The microstructural features having the greatest impact on UTS and YS were the thickness of alpha laths and the width of grain boundary alpha layer, and the microstructural features having the greatest impact on elongation were the thickness of

  2. Brain microstructure mapping using quantitative and diffusion MRI

    International Nuclear Information System (INIS)

    Lebois, Alice

    2014-01-01

    ), in order to better understand their relations and to explain the observed variability along the fascicles and the interhemispheric asymmetries. The second part was focused on the brain tissue modeling at the cell scale to extract the quantitative parameters characterizing the geometry of the cellular membranes, such as the axonal diameter and the axonal density. A diffusion MRI sequence was developed on the 3 Teslas and 7 Teslas Siemens clinical systems of NeuroSpin which is able to apply any kind of gradient waveforms to fall within an approach where the gradient waveform results from an optimization under the hypothesis of a geometrical tissue model, hardware and time constraints induced by clinical applications. This sequence was applied in the study of fourteen healthy subjects in order to build the first quantitative atlas of the axonal diameter and the local axonal density at 7 T. We also proposed a new geometrical model to model the axon, dividing the axonal compartment, usually modelled using a simple cylinder, into two compartments: one being near the membranes with low diffusivity and one farther from the membranes, less restricted and with higher diffusivity. We conducted a theoretical study showing that under clinical conditions, this new model allows, in part, to overcome the bias induced by the simple cylindrical model leading to a systematic overestimation of the smallest diameters. Finally, in the aim of going further in the physiopathology of the autism, we added to the current 3 T imaging protocol the dMRI sequence developed in the framework of this thesis in order to map the axonal diameter and density. This study is ongoing and should validate shortly the contribution of these new quantitative measures of the microstructure in the comprehension of the atrophies of the corpus callosum, initially observed using less specific diffusion parameters such as the generalized fractional anisotropy. There will be other clinical applications in the future

  3. Microstructural evolution and mechanical properties on an ARB processed IF steel studied by X-ray diffraction and EBSD

    Energy Technology Data Exchange (ETDEWEB)

    Cruz-Gandarilla, Francisco, E-mail: fcruz@ipn.mx [Instituto Politécnico Nacional, Escuela Superior de Física y Matemáticas, Edificio 9, U.P.A.L.M., Zacatenco, Del. G. A. Madero, México, D.F. C.P. 07738, México (Mexico); Salcedo-Garrido, Ana María, E-mail: salcedo_marya@yahoo.com.mx [Instituto Politécnico Nacional, Escuela Superior de Física y Matemáticas, Edificio 9, U.P.A.L.M., Zacatenco, Del. G. A. Madero, México, D.F. C.P. 07738, México (Mexico); Bolmaro, Raúl E., E-mail: bolmaro@ifir-conicet.gov.ar [Instituto de Física Rosario, Consejo Nacional de Investigaciones Científicas y Técnicas-CONICET, Universidad Nacional de Rosario, Ocampo y Esmeralda, 2000 Rosario (Argentina); Baudin, Thierry, E-mail: thierry.baudin@u-psud.fr [CNRS, UMR 8182, ICMMO, Lab. de Synthèse, Propriétés et Modélisation des Matériaux, Université de Paris-Sud, Orsay F-91405 (France); De Vincentis, Natalia S., E-mail: devincentis@ifir-conicet.gov.ar [Instituto de Física Rosario, Consejo Nacional de Investigaciones Científicas y Técnicas-CONICET, Universidad Nacional de Rosario, Ocampo y Esmeralda, 2000 Rosario (Argentina); and others

    2016-08-15

    Accumulative Roll Bonding (ARB) is one of the so-called severe plastic deformation (SPD) processes, allowing the production of metals and alloys with ultrafine (micro-nano) structures. Materials with ultrafine grains present attractive properties like the simultaneous increase in strength and ductility. Our interest in these materials is focused on their microstructural evolution during ARB processing, eventually responsible for the enhancement of those mechanical properties. In the current work we follow the evolution of the microstructure in an interstitial-free (IF) steel deformed by ARB after consecutive processing cycles, by means of Electron BackScatter Diffraction (EBSD) and X-ray diffraction (XRD). Particularly, we present results related to texture, grain (GS) and domain sizes, grain boundary character, density of Geometrically Necessary Dislocations (GND), Grain Orientation Spread (GOS), lattice parameters, microstrain, dislocation density and their spatial arrangement. After 5 ARB cycles the system shows a microstructure constituted mainly by submicrometric grains with high angle boundaries and low presence of dislocations inside the grains. - Highlights: •The evolution of microstructure is followed simultaneously by using GAM, GOS and GND (EBSD) and XRD. •LAGBs and subgrains disappear after few cycles SSDs and HAGBs persist at the end. •Dynamic recrystallization counterbalances dislocation arrays and diminishes hardening rate. •Grain size stabilization is revealed as a mechanism for increasing ductility after few ARB cycles.

  4. Age-related changes in bone biochemical markers and their relationship with bone mineral density in normal Chinese women.

    Science.gov (United States)

    Pi, Yin-Zhen; Wu, Xian-Ping; Liu, Shi-Ping; Luo, Xiang-Hang; Cao, Xing-Zhi; Xie, Hui; Liao, Er-Yuan

    2006-01-01

    Measurements of bone biochemical markers are increasingly being used to evaluate the state of bone turnover in the management of bone metabolic diseases, especially osteoporosis. However, changes in the bone turnover rate vary with age. The aim of this study was to establish the laboratory reference range of serum bone-specific alkaline phosphatase (sBAP), serum type I collagen cross-linked C-terminal telopeptide (sCTx), and urine CTx (uCTx), based on values from 665 healthy Chinese women aged 20-80 years. We measured the levels of sBAP, sCTx, serum alkaline phosphatase (sALP), and uCTx and evaluated the age-related changes and their relationship with bone mineral density (BMD) in the anteroposterior (AP) lumbar spine, hip, and left forearm. We found significant correlations between biochemical markers and age, with coefficients of determination (R (2)) of 0.358 for sBAP, 0.126 for sCTx, 0.125 for uCTx, and 0.336 for sALP. The net changes in different biochemical markers were inversely correlated with the rates of BMD loss in the AP lumbar spine. After correction for age, body weight, and height, the levels of the markers had significant negative correlations with the BMD of the AP lumbar spine, femoral neck, and ultradistal forearm. All four biochemical markers had the highest negative correlation with BMD of the AP lumbar spine (partial correlation coefficients of -0.366, -0.296, -0.290, and -0.258 for sBAP, sCTx, uCTx, and sALP, respectively). The mean and SD values of these markers in premenopausal and postmenopausal women with normal BMD values were used as the normal reference ranges. The reference ranges of sBAP, sCTx, and uCTx for pre- vs postmenopausal women were 17.3 +/- 6.23 vs 18.9 +/- 7.52 U/l, 3.18 +/- 1.49 vs 3.23 +/- 1.57 nmol/l, and 15.5 +/- 11.4 vs 16.2 +/- 12.4 nM bone collagen equivalents/mM urinary creatinine, respectively. Levels of the bone formation marker (sBAP) and bone resorption markers (sCTx, uCTx) increased rapidly in women with

  5. SU-F-I-24: Feasibility of Magnetic Susceptibility to Relative Electron Density Conversion Method for Radiation Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Ito, K; Kadoya, N; Chiba, M; Matsushita, H; Jingu, K [Tohoku University Graduate School of Medicine, Sendai, Miyagi (Japan); Sato, K; Nagasaka, T; Yamanaka, K [Tohoku University Hospital, Sendai, Miyagi (Japan); Dobashi, S; Takeda, K [Tohoku University, Sendai, Miyagi (Japan)

    2016-06-15

    Purpose: The aim of this study is to develop radiation treatment planning using magnetic susceptibility obtained from quantitative susceptibility mapping (QSM) via MR imaging. This study demonstrates the feasibility of a method for generating a substitute for a CT image from an MRI. Methods: The head of a healthy volunteer was scanned using a CT scanner and a 3.0 T MRI scanner. The CT imaging was performed with a slice thickness of 2.5 mm at 80 and 120 kV (dual-energy scan). These CT images were converted to relative electron density (rED) using the CT-rED conversion table generated by a previous dual-energy CT scan. The CT-rED conversion table was generated using the conversion of the energy-subtracted CT number to rED via a single linear relationship. One T2 star-weighted 3D gradient echo-based sequence with four different echo times images was acquired using the MRI scanner. These T2 star-weighted images were used to estimate the phase data. To estimate the local field map, a Laplacian unwrapping of the phase and background field removal algorithm were implemented to process phase data. To generate a magnetic susceptibility map from the local field map, we used morphology enabled dipole inversion method. The rED map was resampled to the same resolution as magnetic susceptibility, and the magnetic susceptibility-rED conversion table was obtained via voxel-by-voxel mapping between the magnetic susceptibility and rED maps. Results: A correlation between magnetic susceptibility and rED is not observed through our method. Conclusion: Our results show that the correlation between magnetic susceptibility and rED is not observed. As the next step, we assume that the voxel of the magnetic susceptibility map comprises two materials, such as water (0 ppm) and bone (-2.2 ppm) or water and marrow (0.81ppm). The elements of each voxel were estimated from the ratio of the two materials.

  6. Fracture mechanics and microstructures

    International Nuclear Information System (INIS)

    Gee, M.G.; Morrell, R.

    1986-01-01

    The influence of microstructure on defects in ceramics, and the consequences of their presence for the application of fracture mechanics theories are reviewed. The complexities of microstructures, especially the multiphase nature, the crystallographic anisotropy and the resultant anisotropic physical properties, and the variation of microstructure and surface finish from point to point in real components, all lead to considerable uncertainties in the actual performance of any particular component. It is concluded that although the concepts of fracture mechanics have been and will continue to be most useful for the qualitative explanation of fracture phenomena, the usefulness as a predictive tool with respect to most existing types of material is limited by the interrelation between material microstructure and mechanical properties. At present, the only method of eliminating components with unsatisfactory mechanical properties is to proof-test them, despite the fact that proof-testing itself is limited in ability to cope with changes to the component in service. The aim of the manufacturer must be to improve quality and consistency within individual components, from component to component, and from batch to batch. The aim of the fracture specialist must be to study longer-term properties to improve the accuracy of behaviour predictions with a stronger data base. Materials development needs to concentrate on obtaining defect-free materials that can be translated into more-reliable products, using our present understanding of the influence of microstructure on strength and toughness

  7. Tissue microstructure estimation using a deep network inspired by a dictionary-based framework.

    Science.gov (United States)

    Ye, Chuyang

    2017-12-01

    Diffusion magnetic resonance imaging (dMRI) captures the anisotropic pattern of water displacement in the neuronal tissue and allows noninvasive investigation of the complex tissue microstructure. A number of biophysical models have been proposed to relate the tissue organization with the observed diffusion signals, so that the tissue microstructure can be inferred. The Neurite Orientation Dispersion and Density Imaging (NODDI) model has been a popular choice and has been widely used for many neuroscientific studies. It models the diffusion signal with three compartments that are characterized by distinct diffusion properties, and the parameters in the model describe tissue microstructure. In NODDI, these parameters are estimated in a maximum likelihood framework, where the nonlinear model fitting is computationally intensive. Therefore, efforts have been made to develop efficient and accurate algorithms for NODDI microstructure estimation, which is still an open problem. In this work, we propose a deep network based approach that performs end-to-end estimation of NODDI microstructure, which is named Microstructure Estimation using a Deep Network (MEDN). MEDN comprises two cascaded stages and is motivated by the AMICO algorithm, where the NODDI microstructure estimation is formulated in a dictionary-based framework. The first stage computes the coefficients of the dictionary. It resembles the solution to a sparse reconstruction problem, where the iterative process in conventional estimation approaches is unfolded and truncated, and the weights are learned instead of predetermined by the dictionary. In the second stage, microstructure properties are computed from the output of the first stage, which resembles the weighted sum of normalized dictionary coefficients in AMICO, and the weights are also learned. Because spatial consistency of diffusion signals can be used to reduce the effect of noise, we also propose MEDN+, which is an extended version of MEDN. MEDN

  8. The Relations Between Soil Water Retention Characteristics, Particle Size Distributions, Bulk Densities and Calcium Carbonate Contents for Danish Soils

    DEFF Research Database (Denmark)

    Jensen, Niels H.; Balstrøm, Thomas; Breuning-Madsen, Henrik

    2005-01-01

    functions developed in HYPRES (Hydraulic Properties of European Soils). Introducing bulk density as a predictor improved the equation for pressure head –1 kPa but not for lower ones. The grouping of data sets in surface and subsurface horizons or in textural classes did not improve the equations. Based...

  9. Nest densities of cavity-nesting birds in relation to postfire salvage logging and time since wildfire

    Science.gov (United States)

    Victoria A. Saab; Robin E. Russell; Jonathan G. Dudley

    2007-01-01

    We monitored the nest densities and nest survival of seven cavity-nesting bird species, including four open-space foragers (American Kestrel [Falco sparverius], Lewis's Woodpecker [Melanerpes lewis], Western Bluebird [Sialia mexicana], and Mountain Bluebird [S. currucoides]) and three wood...

  10. Dietary Energy Density in Relation to Subsequent Changes of Weight and Waist Circumference in European Men and Women

    NARCIS (Netherlands)

    Du, H.; Ginder, V.; Jebb, S.A.; Forouchi, N.G.; Wareham, N.; Halkjaer, J.; Tjonneland, A.; Overvad, K.; Jakobsen, M.U.; Buijsse, B.; Steffen, A.; Palli, D.; Masala, G.; Saris, W.H.; Sorensen, T.; Feskens, E.J.M.

    2009-01-01

    Background - Experimental studies show that a reduction in dietary energy density (ED) is associated with reduced energy intake and body weight. However, few observational studies have investigated the role of ED on long-term weight and waist circumference change. Methods and Principal Findings -

  11. The relation between 25-hydroxyvitamin D with peak bone mineral density and body composition in healthy young adults

    NARCIS (Netherlands)

    Boot, Annemieke M.; Krenning, Eric P.; Keizer-Schrama, Sabine M. P. F. de Muinck

    Objective: The associations between peak bone mineral density (BMD) and body composition with 25 hydroxyvitamin D (25OHD) levels in healthy young adults were evaluated. Methods: The number of participants was 464; 347 women and 117 men. The mean age was 24.3 years (range 17-31 years). BMD of the

  12. A comparison of the relative locations of the mid-latitude electron density trough and the scintillation boundary

    International Nuclear Information System (INIS)

    Tulunay, Y.K.; Demir, O.; Tauriainen, A.

    1976-01-01

    The mid-latitude electron density trough position and the scintillation boundary have been compared for magnetically quiet periods by using the data returned by Ariel 3 and Explorer 22 satellites. The scintillation boundary is found southward of the trough during daytime, but at night the positions are reversed. (author)

  13. Flaking behavior and microstructure evolution of nickel and copper powder during mechanical milling in liquid environment

    International Nuclear Information System (INIS)

    Xiao Xiao; Zeng Zigao; Zhao Zhongwei; Xiao Songwen

    2008-01-01

    To prepare metal flakes with a high flaking level and investigate the microstructure of metal flakes, nickel and copper powder were mechanically milled in liquid environment and the microstructure of powders was investigated by X-ray diffraction. The milling process can be divided into flaking and broken stages. At the flaking stage, milled metal powders exhibited high flaking level and flaky microshape, and became preferred orientation. While at the broken stage, the milled powders presented a low flaking level and irregular microshape, and was not preferred orientation any longer. The grain size, microstrain and dislocation density along direction varied with milling time differently from that along direction. The flaking level of the milled powders was related to the preferred orientation, and more closely to the deformation mechanism. We can strengthen the formation of preferred orientation to obtain metal powders with a high flaking level

  14. Flaking behavior and microstructure evolution of nickel and copper powder during mechanical milling in liquid environment

    Energy Technology Data Exchange (ETDEWEB)

    Xiao Xiao [College of Metallurgical Science and Engineering, Central South University, Changsha 410083, Hunan (China); Changsha Research Institute of Mining and Metallurgy, Changsha 410012, Hunan (China); Zeng Zigao [Changsha Research Institute of Mining and Metallurgy, Changsha 410012, Hunan (China); Zhao Zhongwei [College of Metallurgical Science and Engineering, Central South University, Changsha 410083, Hunan (China); Xiao Songwen [Changsha Research Institute of Mining and Metallurgy, Changsha 410012, Hunan (China)], E-mail: swinxiao@yahoo.com.cn

    2008-02-25

    To prepare metal flakes with a high flaking level and investigate the microstructure of metal flakes, nickel and copper powder were mechanically milled in liquid environment and the microstructure of powders was investigated by X-ray diffraction. The milling process can be divided into flaking and broken stages. At the flaking stage, milled metal powders exhibited high flaking level and flaky microshape, and <2 0 0> became preferred orientation. While at the broken stage, the milled powders presented a low flaking level and irregular microshape, and <2 0 0> was not preferred orientation any longer. The grain size, microstrain and dislocation density along <2 0 0> direction varied with milling time differently from that along <1 1 1> direction. The flaking level of the milled powders was related to the <2 0 0> preferred orientation, and more closely to the deformation mechanism. We can strengthen the formation of <2 0 0> preferred orientation to obtain metal powders with a high flaking level.

  15. The three-dimensional microstructure of polycrystalline materials unravelled by synchrotron light

    International Nuclear Information System (INIS)

    Ludwig, W.; Herbig, M.; Ludwig, W.; King, A; Reischig, P.; Marrow, J.; Babout, L.; Mejdal Lauridsen, E.; Proudhon, H.

    2011-01-01

    Synchrotron radiation X-ray imaging and diffraction techniques offer new possibilities for non-destructive bulk characterization of polycrystalline materials. Minute changes in electron density (different crystallographic phases, cracks, porosities) can be detected using 3D imaging modes exploiting Fresnel diffraction and the coherence properties of third generation synchrotron beams. X-ray diffraction contrast tomography, a technique based on Bragg diffraction imaging, provides access to the 3D shape, orientation and elastic strain state of the individual grains from polycrystalline sample volumes containing several hundred up to a few thousand grains. Combining both imaging modalities allows a comprehensive description of the microstructure of the material at the micrometer length scale. Repeated observations during (interrupted) mechanical tests provide unprecedented insight into crystallographic and grain microstructure related aspects of polycrystal deformation and degradation mechanisms in materials, fulfilling some conditions on grain size and deformation state. (authors)

  16. Microstructure, mechanical behavior and biocompatibility of powder metallurgy Nb-Ti-Ta alloys as biomedical material.

    Science.gov (United States)

    Liu, Jue; Chang, Lin; Liu, Hairong; Li, Yongsheng; Yang, Hailin; Ruan, Jianming

    2017-02-01

    Microstructures, mechanical properties, apatite-forming ability and in vitro experiments were studied for Nb-25Ti-xTa (x=10, 15, 20, 25, 35at.%) alloys fabricated by powder metallurgy. It is confirmed that the alloys could achieve a relative density over 80%. Meanwhile, the increase in Ta content enhances the tensile strength, elastic modulus and hardness of the as-sintered alloys. When increasing the sintering temperatures, the microstructure became more homogeneous for β phase, resulting in a decrease in the modulus and strength. Moreover, the alloys showed a good biocompatibility due to the absence of cytotoxic elements, and were suitable for apatite formation and cell adhesion. In conclusion, Nb-25Ti-xTa alloys are potentially useful in biomedical applications with their mechanical and biological properties being evaluated in this work. Copyright © 2016 Elsevier B.V. All rights reserved.

  17. The relation between fine root density and proximity of stems in closed Douglas-fir plantations on homogen[e]ous sandy soils: implications for sampling design

    NARCIS (Netherlands)

    Olsthoorn, A.F.M.; Klap, J.M.; Oude Voshaar, J.H.

    1999-01-01

    Studies have been carried out in two fully stocked, fast growing Douglas-fir plantations of the Dutch ACIFORN project in three consecutive years, to obtain information on fine root densities (Olsthoorn 1991). For the present paper, data collected in early summer 1987 were used to study the relation

  18. Microstructuring of glasses

    CERN Document Server

    Hülsenberg, Dagmar; Bismarck, Alexander

    2008-01-01

    As microstructured glass becomes increasingly important for microsystems technology, the main application fields include micro-fluidic systems, micro-analysis systems, sensors, micro-actuators and implants. And, because glass has quite distinct properties from silicon, PMMA and metals, applications exist where only glass devices meet the requirements. The main advantages of glass derive from its amorphous nature, the precondition for its - theoretically - direction-independent geometric structurability. Microstructuring of Glasses deals with the amorphous state, various glass compositions and their properties, the interactions between glasses and the electromagnetic waves used to modify it. Also treated in detail are methods for influencing the geometrical microstructure of glasses by mechanical, chemical, thermal, optical, and electrical treatment, and the methods and equipment required to produce actual microdevices.

  19. Increased stocking density causes changes in expression of selected stress- and immune-related genes, humoral innate immune parameters and stress responses of rainbow trout (Oncorhynchus mykiss).

    Science.gov (United States)

    Yarahmadi, Peyman; Miandare, Hamed Kolangi; Fayaz, Sahel; Caipang, Christopher Marlowe A

    2016-01-01

    The present study investigated the effects of various stocking densities on the health status (stress and immune responses) of rainbow trout (Onchorhynchus mykiss). Juvenile rainbow trout were acclimated, placed in circular tanks under stocking densities of 10, 40 and 80 kg m(-3) and reared for 30 days. The relative expression of genes involved in stress and immunity such as HSP70, LyzII, TNF-1α, IL-1β, IL-8 and IFN-γ1 in the head kidney was determined. Serum cortisol, ACTH, total antioxidant capacity, osmolality and lactate were measured after 30 days of culture at different stocking densities (D1:10 kg m(-3), D2: 40 kg m(-3) and D3: 80 kg m(-3)) as indices of stress responses. In addition, the effects of stocking densities on serum complement, bactericidal activity, agglutinating antibody titers, serum IgM, anti-protease activity, serum total protein and alkaline phosphatase of the fish were measured. HSP70 gene expression was significantly density-dependent upregulated in D2 and D3 densities compared to D1 (P < 0.05). Also, there was significant downregulation in expression of LyzII, TNF-1α, IL-1β, IL-8 and IFN-γ1 in fish reared at density of either D2 or D3 (P < 0.05). In terms of stress responses, serum ACTH, cortisol and lactate level showed significant density-dependent increase (P < 0.05) while serum osmolality and total antioxidant capacity showed significant decline (P < 0.05) in fish reared at higher densities (D2 and D3) compared to fish reared at lower density (D1) (P < 0.05). Concordant with the expression of the immune-related genes, the serum complement and bactericidal activity as well as specific antibody titer against Aeromonas hydrophila, IgM and anti-protease activity decreased along with elevation of stocking density from D1 to D3 (P < 0.05). However, different stocking densities had no significant effect on serum total protein level and alkaline phosphatase activity. These results suggested that elevation of stocking

  20. Microstructure of irradiated materials

    International Nuclear Information System (INIS)

    Robertson, I.M.

    1995-01-01

    The focus of the symposium was on the changes produced in the microstructure of metals, ceramics, and semiconductors by irradiation with energetic particles. the symposium brought together those working in the different material systems, which revealed that there are a remarkable number of similarities in the irradiation-produced microstructures in the different classes of materials. Experimental, computational and theoretical contributions were intermixed in all of the sessions. This provided an opportunity for these groups, which should interact, to do so. Separate abstracts were prepared for 58 papers in this book

  1. Factors in secondary prevention subsequent to distal radius fracture : Focus on physical function, co-morbidity, bone mineral density and health-related quality of life

    OpenAIRE

    Nordvall, Helena

    2009-01-01

    In Sweden approximately 25000 distal radius fractures occur annually, which is 37 % of all fractures related to osteoporosis. In this thesis, risk factors for osteoporosis, bone mineral density (BMD) and health-related quality of life (the SF-36) were compared in patients who suffered a distal radius fracture after low energy trauma with a control group matched on the basis of age, gender, and municipality of residence. The aim was also to analyse, among these patients, whether a risk factor ...

  2. Determination of the relative power density distribution in a heterogeneous reactor from the results of measurements of the reactivity effects and the neutron importance function

    International Nuclear Information System (INIS)

    Bobrov, A. A.; Glushkov, E. S.; Zimin, A. A.; Kapitonova, A. V.; Kompaniets, G. V.; Nosov, V. I.; Petrushenko, R. P.; Smirnov, O. N.

    2012-01-01

    A method for experimental determination of the relative power density distribution in a heterogeneous reactor based on measurements of fuel reactivity effects and importance of neutrons from a californium source is proposed. The method was perfected on two critical assembly configurations at the NARCISS facility of the Kurchatov Institute, which simulated a small-size heterogeneous nuclear reactor. The neutron importance measurements were performed on subcritical and critical assemblies. It is shown that, along with traditionally used activation methods, the developed method can be applied to experimental studies of special features of the power density distribution in critical assemblies and reactors.

  3. SDSS-IV MaNGA: Probing the Kinematic Morphology–Density Relation of Early-type Galaxies with MaNGA

    Science.gov (United States)

    Greene, J. E.; Leauthaud, A.; Emsellem, E.; Goddard, D.; Ge, J.; Andrews, B. H.; Brinkman, J.; Brownstein, J. R.; Greco, J.; Law, D.; Lin, Y.-T.; Masters, K. L.; Merrifield, M.; More, S.; Okabe, N.; Schneider, D. P.; Thomas, D.; Wake, D. A.; Yan, R.; Drory, N.

    2017-12-01

    The “kinematic” morphology–density relation for early-type galaxies posits that those galaxies with low angular momentum are preferentially found in the highest-density regions of the universe. We use a large sample of galaxy groups with halo masses {10}12.5MaNGA) survey to examine whether there is a correlation between local environment and rotational support that is independent of stellar mass. We find no compelling evidence for a relationship between the angular momentum content of early-type galaxies and either local overdensity or radial position within the group at fixed stellar mass.

  4. Variability in body mass and sexual dimorphism in Danish red foxes (Vulpes vulpes) in relation to population density

    DEFF Research Database (Denmark)

    Pagh, Sussie; Hansen, Mette Sif; Jensen, Birger

    2018-01-01

    For the first time, temporal variability in body size and sexual dimorphism is revealed in foxes Vulpes vulpes from the same geographical area at over time. The weights and lengths of 552 Danish foxes were documented during three different periods: 1965–1977, 2012–2014 and the winter of 2015...... of 2012–2014, no difference in body fat measured by rump fat thickness (RFT) was found between age groups and genders in contrast to 2015/2016, when RFT was significantly (p ...–1977 and compared to 2015/2016, compared to 2012–2014, when population density was high (the mean weight: 6.8 kg). However, no significant differences were found in the weight of females. Hence, sexual dimorphism ranged from 7.6 to 3.6 in adult foxes in low and high-density periods, respectively. During the winters...

  5. Capillary ultrastructure and mitochondrial volume density in skeletal muscle in relation to reduced exercise capacity of patients with intermittent claudication

    DEFF Research Database (Denmark)

    Baum, Oliver; Torchetti, Eleonora; Malik, Corinna

    2016-01-01

    power output (PPO) was determined for all participants using an incremental single-leg knee-extension protocol. Capillary density was lower (411±90 mm(-2)versus 506±95 mm(-2); P≤0.05) in the biopsies of the IC patients than in those of the controls. The basement membrane (BM) around capillaries...... was thicker (543±82 nm versus 423±97 nm; P≤0.01) and the volume density of mitochondria was lower (3.51±0.56% versus 4.60±0.74; P≤0.01) in the IC-patients than the controls. In the IC-patients, a higher proportion of capillaries appeared with collapsed slit-like lumen and/or swollen endothelium. PPO was lower...

  6. The relation between 25-hydroxyvitamin D with peak bone mineral density and body composition in healthy young adults.

    Science.gov (United States)

    Boot, Annemieke M; Krenning, Eric P; de Muinck Keizer-Schrama, Sabine M P F

    2011-01-01

    The associations between peak bone mineral density (BMD) and body composition with 25 hydroxyvitamin D (25OHD) levels in healthy young adults were evaluated. The number of participants was 464; 347 women and 117 men. The mean age was 24.3 years (range 17-31 years). BMD of the lumbar spine, total body and femoral neck (FN) and body composition were measured by dual energy X-ray absorptiometry. Volumetric BMD, bone mineral apparent density (BMAD), of the lumbar spine and FN was calculated. In females, 25OHD level was positively associated with FN BMD and BMAD (both ppercentage body fat (pbody BMD and lean body mass (p=0.03 and p=0.01). 25OHD level is a determinant of peak BMD in both sexes. Vitamin D status was associated with body fat in females and with lean body mass in males.

  7. Dietary energy density in relation to subsequent changes of weight and waist circumference in European men and women

    DEFF Research Database (Denmark)

    Du, Huaidong; van der A, Daphne L; Ginder, Vanessa

    2009-01-01

    BACKGROUND: Experimental studies show that a reduction in dietary energy density (ED) is associated with reduced energy intake and body weight. However, few observational studies have investigated the role of ED on long-term weight and waist circumference change. METHODS AND PRINCIPAL FINDINGS: T...... not prevent weight gain but have a weak yet potentially beneficial effect on the prevention of abdominal obesity as measured by waist circumference....

  8. Tumor characteristics and family history in relation to mammographic density and breast cancer: The French E3N cohort.

    Science.gov (United States)

    Maskarinec, Gertraud; Dartois, Laureen; Delaloge, Suzette; Hopper, John; Clavel-Chapelon, Françoise; Baglietto, Laura

    2017-08-01

    Mammographic density is a known heritable risk factor for breast cancer, but reports how tumor characteristics and family history may modify this association are inconsistent. Dense and total breast areas were assessed using Cumulus™ from pre-diagnostic mammograms for 820 invasive breast cancer cases and 820 matched controls nested within the French E3N cohort study. To allow comparisons across models, percent mammographic density (PMD) was standardized to the distribution of the controls. Odds ratios (OR) and 95% confidence intervals (CI) of breast cancer risk for mammographic density were estimated by conditional logistic regression while adjusting for age and body mass index. Heterogeneity according to tumor characteristic and family history was assessed using stratified analyses. Overall, the OR per 1 SD for PMD was 1.50 (95% CI, 1.33-1.69). No evidence for significant heterogeneity by tumor size, lymph node status, grade, and hormone receptor status (estrogen, progesterone, and HER2) was detected. However, the association of PMD was stronger for women reporting a family history of breast cancer (OR 1SD =2.25; 95% CI, 1.67-3.04) than in women reporting none (OR 1SD =1.41; 95% CI, 1.24-1.60; p heterogeneity =0.002). Similarly, effect modification by FHBC was observed using categories of PMD (p heterogeneity =0.02) with respective ORs of 15.16 (95% CI, 4.23-54.28) vs. 3.14 (95% CI, 1.89-5.22) for ≥50% vs. breast cancer risk with a family history supports the hypothesis of shared genetic factors responsible for familial aggregation of breast cancer and the heritable component of mammographic density. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. Densities of Barrow's goldeneyes during winter in Prince William Sound, Alaska in relation to habitat, food, and history of oil contamination

    Science.gov (United States)

    Esler, Daniel N.; Bowman, Timothy D.; O'Clair, Charles E.; Dean, Thomas A.; McDonald, Lyman L.

    2000-01-01

    We evaluated variation in densities of Barrow's Goldeneyes (Bucephala islandica) during winter at 214 sites within oiled and unoiled study areas in Prince William Sound, Alaska in relation to physical habitat attributes, prey biomass, and history of habitat contamination by the 1989 Exxon Valdez oil spill. Using general linear model analyses, we found that goldeneye densities were positively associated with occurrence of a stream within 200 m, lack of exposure to wind and waves, and mixed (versus rocky) substrate. We speculate that these associations relate to habitat profitability via selection of beneficial attributes and avoidance of detrimental features. We also determined that biomass of blue mussels (Mytilus trossulus), the primary prey, was not related to Barrow's Goldeneye densities; we suggest that mussel standing stock exceeds predation demands in our study areas and, thus, does not dictate goldeneye distribution. After accounting for habitat effects, we detected no effect of history of oil contamination on Barrow's Goldeneye densities, suggesting that populations have recovered from the oil spill. Although other studies documented hydrocarbon exposure in Barrow's Goldeneyes through at least 1997, either the level of exposure did not affect populations via reductions in survival, or effects of oil exposure were offset by immigration.

  10. The role of cone-beam breast-CT for breast cancer detection relative to breast density

    Energy Technology Data Exchange (ETDEWEB)

    Wienbeck, Susanne; Uhlig, Johannes; Fintel, Eva von; Stahnke, Vera; Lotz, Joachim [University Medical Center Goettingen, Institute for Diagnostic and Interventional Radiology, Goettingen (Germany); Luftner-Nagel, Susanne; Fischer, Uwe [Diagnostic Breast Center Goettingen, Goettingen (Germany); Zapf, Antonia [University Medical Center Goettingen, Department of Medical Statistics, Goettingen (Germany); Surov, Alexey [University of Leipzig, Department of Diagnostic and Interventional Radiology, Leipzig (Germany)

    2017-12-15

    To evaluate the impact of breast density on the diagnostic accuracy of non-contrast cone-beam breast computed tomography (CBBCT) in comparison to mammography for the detection of breast masses. A retrospective study was conducted from August 2015 to July 2016. Fifty-nine patients (65 breasts, 112 lesions) with BI-RADS, 5th edition 4 or 5 assessment in mammography and/or ultrasound of the breast received an additional non-contrast CBBCT. Independent double blind reading by two radiologists was performed for mammography and CBBCT imaging. Sensitivity, specificity and AUC were compared between the modalities. Breast lesions were histologically examined in 85 of 112 lesions (76%). The overall sensitivity for CBBCT (reader 1: 91%, reader 2: 88%) was higher than in mammography (both: 68%, p<0.001), and also for the high-density group (p<0.05). The specificity and AUC was higher for mammography in comparison to CBBCT (p<0.05 and p<0.001). The interobserver agreement (ICC) between the readers was 90% (95% CI: 86-93%) for mammography and 87% (95% CI: 82-91%) for CBBCT. Compared with two-view mammography, non-contrast CBBCT has higher sensitivity, lower specificity, and lower AUC for breast mass detection in both high and low density breasts. (orig.)

  11. Microstructure and Mechanical Property of Aluminum Alloy Plate AA 7055

    Directory of Open Access Journals (Sweden)

    CHEN Junzhou

    2017-10-01

    Full Text Available Through-thickness microstructure and mechanical property of AA 7055-T7751 aluminum alloy plate were investigated by using electron backscattered diffraction (EBSD, transmission electron microscope (TEM and small angle X-ray scattering(SAXS. The results indicate an inhomogeneous distribution of microstructure through the thickness. The degree of recrystallization decreases gradually from 69% to 19.1%, as deepening from the surface to the center of the plate. The size of subgrains decreases from 10 μm at the surface to around 2 μm at the center. Strong texture of rolling type is observed near the center but the intensity decreases gradually as nearing the surface and the shear texture becomes the dominant. High density of plate-like η' phases are observed in the alloy, indicating the sufficient precipitation. η' precipitates of this condition are around 3.7 nm in radius, 1-3 nm in thickness and are found coherent with the Al matrix with a coherent strain of 0.0133, showing a strong strengthening effect. The heterogeneity in grain scale does not influence the distribution and the morphology of precipitates. The yield strength (L direction varies linearly along the thickness direction of the plate, fitting an equation of σy=-38.7S+604.8 (0≤S≤1. The variation of yield strength is related to the heterogeneity of grain structure.

  12. Genotypes and haplotypes in the insulin-like growth factors, their receptors and binding proteins in relation to plasma metabolic levels and mammographic density

    Directory of Open Access Journals (Sweden)

    Chanock Stephen J

    2010-03-01

    Full Text Available Abstract Background Increased mammographic density is one of the strongest independent risk factors for breast cancer. It is believed that one third of breast cancers are derived from breasts with more than 50% density. Mammographic density is affected by age, BMI, parity, and genetic predisposition. It is also greatly influenced by hormonal and growth factor changes in a woman's life cycle, spanning from puberty through adult to menopause. Genetic variations in genes coding for hormones and growth factors involved in development of the breast are therefore of great interest. The associations between genetic polymorphisms in genes from the IGF pathway on mammographic density and circulating levels of IGF1, its binding protein IGFBP3, and their ratio in postmenopausal women are reported here. Methods Samples from 964 postmenopausal Norwegian women aged 55-71 years were collected as a part of the Tromsø Mammography and Breast Cancer Study. All samples were genotyped for 25 SNPs in IGF1, IGF2, IGF1R, IGF2R, IGFALS and IGFBP3 using Taqman (ABI. The main statistical analyses were conducted with the PROC HAPLOTYPE procedure within SAS/GENETICS™ (SAS 9.1.3. Results The haplotype analysis revealed six haploblocks within the studied genes. Of those, four had significant associations with circulating levels of IGF1 or IGFBP3 and/or mammographic density. One haplotype variant in the IGF1 gene was found to be associated with mammographic density. Within the IGF2 gene one haplotype variant was associated with levels of both IGF1 and IGFBP3. Two haplotype variants in the IGF2R were associated with the level of IGF1. Both variants of the IGFBP3 haplotype were associated with the IGFBP3 level and indicate regulation in cis. Conclusion Polymorphisms within the IGF1 gene and related genes were associated with plasma levels of IGF1, IGFBP3 and mammographic density in this study of postmenopausal women.

  13. Effect of two-stage sintering process on microstructure and mechanical properties of ODS tungsten heavy alloy

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Kyong H. [Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology, 373-1 Kusong-dong, Yusong-gu, Taejon 305-701 (Korea, Republic of); Cha, Seung I. [International Center for Young Scientists, National Institute for Materials Science 1-1, Namiki, Tsukuba 305-0044 (Japan); Ryu, Ho J. [DUPIC, Korea Atomic Energy Research Institute, 150 Deokjin-dong, Yusong-gu, Taejon 305-353 (Korea, Republic of); Hong, Soon H. [Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology, 373-1 Kusong-dong, Yusong-gu, Taejon 305-701 (Korea, Republic of)], E-mail: shhong@kaist.ac.kr

    2007-06-15

    Oxide dispersion strengthened (ODS) tungsten heavy alloys have been considered as promising candidates for advanced kinetic energy penetrator due to their characteristic fracture mode compared to conventional tungsten heavy alloy. In order to obtain high relative density, the ODS tungsten heavy alloy needs to be sintered at higher temperature for longer time, however, induces growth of tungsten grains. Therefore, it is very difficult to obtain controlled microstructure of ODS tungsten heavy alloy having fine tungsten grains with full densification. In this study, two-stage sintering process, consisted of primary solid-state sintering and followed by secondary liquid phase sintering, was introduced for ODS tungsten heavy alloys. The mechanically alloyed 94W-4.56Ni-1.14Fe-0.3Y{sub 2}O{sub 3} powders are solid-state sintered at 1300-1450 deg. C for 1 h in hydrogen atmosphere, and followed by liquid phase sintering temperature at 1465-1485 deg. C for 0-60 min. The microstructure of ODS tungsten heavy alloys showed high relative density above 97%, with contiguous tungsten grains after primary solid-state sintering. The microstructure of solid-state sintered ODS tungsten heavy alloy was changed into spherical tungsten grains embedded in W-Ni-Fe matrix during secondary liquid phase sintering. The two-stage sintered ODS tungsten heavy alloy from mechanically alloyed powders showed finer microstructure and higher mechanical properties than conventional liquid phase sintered alloy. The mechanical properties of ODS tungsten heavy alloys are dependent on the microstructural parameters such as tungsten grain size, matrix volume fraction and tungsten/tungsten contiguity, which can be controlled through the two-stage sintering process.

  14. Impairment in explicit visuomotor sequence learning is related to loss of microstructural integrity of the corpus callosum in multiple sclerosis patients with minimal disability.

    Science.gov (United States)

    Bonzano, L; Tacchino, A; Roccatagliata, L; Sormani, M P; Mancardi, G L; Bove, M

    2011-07-15

    Sequence learning can be investigated by serial reaction-time (SRT) paradigms. Explicit learning occurs when subjects have to recognize a test sequence and has been shown to activate the frontoparietal network in both contralateral and ipsilateral hemispheres. Thus, the left and right superior longitudinal fasciculi (SLF), connecting the intra-hemispheric frontoparietal circuits, could have a role in explicit unimanual visuomotor learning. Also, as both hemispheres are involved, we could hypothesize that the corpus callosum (CC) has a role in this process. Pathological damage in both SLF and CC has been detected in patients with Multiple Sclerosis (PwMS), and microstructural alterations can be quantified by Diffusion Tensor Imaging (DTI). In light of these findings, we inquired whether PwMS with minimal disability showed impairments in explicit visuomotor sequence learning and whether this could be due to loss of white matter integrity in these intra- and inter-hemispheric white matter pathways. Thus, we combined DTI analysis with a modified version of SRT task based on finger opposition movements in a group of PwMS with minimal disability. We found that the performance in explicit sequence learning was significantly reduced in these patients with respect to healthy subjects; the amount of sequence-specific learning was found to be more strongly correlated with fractional anisotropy (FA) in the CC (r=0.93) than in the left (r=0.28) and right SLF (r=0.27) (p for interaction=0.005 and 0.04 respectively). This finding suggests that an inter-hemispheric information exchange between the homologous areas is required to successfully accomplish the task and indirectly supports the role of the right (ipsilateral) hemisphere in explicit visuomotor learning. On the other hand, we found no significant correlation of the FA in the CC and in the SLFs with nonspecific learning (assessed when stimuli are randomly presented), supporting the hypothesis that inter

  15. Longitudinal development of thalamic and internal capsule microstructure in autism spectrum disorder.

    Science.gov (United States)

    McLaughlin, Kristine; Travers, Brittany G; Dadalko, Olga I; Dean, Douglas C; Tromp, Do; Adluru, Nagesh; Destiche, Daniel; Freeman, Abigail; Prigge, Molly D; Froehlich, Alyson; Duffield, Tyler C; Zielinski, Brandon A; Bigler, Erin D; Lange, Nicholas; Anderson, Jeff S; Alexander, Andrew L; Lainhart, Janet E

    2018-03-01

    The thalamus is a key sensorimotor relay area that is implicated in autism spectrum disorder (ASD). However, it is unknown how the thalamus and white-matter structures that contain thalamo-cortical fiber connections (e.g., the internal capsule) develop from childhood into adulthood and whether this microstructure relates to basic motor challenges in ASD. We used diffusion weighted imaging in a cohort-sequential design to assess longitudinal development of the thalamus, and posterior- and anterior-limbs of the internal capsule (PLIC and ALIC, respectively) in 89 males with ASD and 56 males with typical development (3-41 years; all verbal). Our results showed that the group with ASD exhibited different developmental trajectories of microstructure in all regions, demonstrating childhood group differences that appeared to approach and, in some cases, surpass the typically developing group in adolescence and adulthood. The PLIC (but not ALIC nor thalamus) mediated the relation between age and finger-tapping speed in both groups. Yet, the gap in finger-tapping speed appeared to widen at the same time that the between-group gap in the PLIC appeared to narrow. Overall, these results suggest that childhood group differences in microstructure of the thalamus and PLIC become less robust in adolescence and adulthood. Further, finger-tapping speed appears to be mediated by the PLIC in both groups, but group differences in motor speed that widen during adolescence and adulthood suggest that factors beyond the microstructure of the thalamus and internal capsule may contribute to atypical motor profiles in ASD. Autism Res 2018, 11: 450-462. © 2017 International Society for Autism Research, Wiley Periodicals, Inc. Microstructure of the thalamus, a key sensory and motor brain area, appears to develop differently in individuals with autism spectrum disorder (ASD). Microstructure is important because it informs us of the density and organization of different brain tissues. During

  16. Microstructured optical fibers for gas sensing systems

    Science.gov (United States)

    Challener, William Albert; Choudhury, Niloy; Palit, Sabarni

    2017-10-17

    Microstructured optical fiber (MOF) includes a cladding extending a length between first and second ends. The cladding includes an inner porous microstructure that at least partially surrounds a hollow core. A perimeter contour of the hollow core has a non-uniform radial distance from a center axis of the cladding such that first segments of the cladding along the perimeter contour have a shorter radial distance from the center axis relative to second segments of the cladding along the perimeter contour. The cladding receives and propagates light energy through the hollow core, and the inner porous microstructure substantially confines the light energy within the hollow core. The cladding defines at least one port hole that extends radially from an exterior surface of the cladding to the hollow core. Each port hole penetrates the perimeter contour of the hollow core through one of the second segments of the cladding.

  17. A New Microstructure Device for Efficient Evaporation of Liquids

    Science.gov (United States)

    Brandner, Juergen J.; Maikowske, Stefan; Vittoriosi, Alice

    Evaporation of liquids is of major interest for many topics in process engineering. One of these is chemical process engineering, where evaporation of liquids and generation of superheated steam is mandatory for numerous processes. Generally, this is performed by use of classical pool boiling and evaporation process equipment. Another possibility is creating mixtures of gases and liquids, combined with a heating of this haze. Both methods provide relatively limited performance. Due to the advantages of microstructure devices especially in chemical process engineering [1] the interest in microstructure evaporators and steam generators have been increased through the last decade. In this publication several microstructure devices used for evaporation and generation of steam as well as superheating will be described. Here, normally electrically powered devices containing micro channels as well as non-channel microstructures are used due to better controllability of the temperature level. Micro channel heat exchangers have been designed, manufactured and tested at the Institute for Micro Process Engineering of the Karlsruhe Institute of Technology for more than 15 years. Starting with the famous Karlsruhe Cube, a cross-flow micro channel heat exchanger of various dimensions, not only conventional heat transfer between liquids or gases have been theoretically and experimentally examined but also phase transition from liquids to gases (evaporation) and condensation of liquids. However, the results obtained with sealed microstructure devices have often been unsatisfying. Thus, to learn more onto the evaporation process itself, an electrically powered device for optical inspection of the microstructures and the processes inside has been designed and manufactured [2]. This was further optimized and improved for better controllability and reliable experiments [3]. Exchangeable metallic micro channel array foils as well as an optical inspection of the evaporation process by

  18. Microstructure characterizaton of advanced oxide fuel

    International Nuclear Information System (INIS)

    Rasmussen, D.E.; Gerber, E.W.; McCord, R.B.

    1977-01-01

    Preirradiation porosity, grain size, and microcomposition characteristics are presented for selected advanced oxide (PuO 2 -UO 2 ) LMFBR developmental fuels fabricated for irradiation testing in EBR-II. Quantitative microscopy, electron microprobe analysis, and a recently developed quantitative autoradiographic technique are utilized to relate microstructure characteristics to fabrication parameters

  19. Stress hormones in relation to breeding status and territory location in colonial king penguin: a role for social density?

    Science.gov (United States)

    Viblanc, Vincent A; Gineste, Benoit; Stier, Antoine; Robin, Jean-Patrice; Groscolas, René

    2014-07-01

    Because glucocorticoid (stress) hormones fundamentally affect various aspects of the behaviour, life history and fitness of free-living vertebrates, there is a need to understand the environmental factors shaping their variation in natural populations. Here, we examined whether spatial heterogeneity in breeding territory quality affected the stress of colonial king penguin (Aptenodytes patagonicus). We assessed the effects of local climate (wind, sun and ambient temperature) and social conditions (number of neighbours, distance to neighbours) on the baseline levels of plasma total corticosterone (CORT) in 77 incubating and 42 chick-brooding birds, breeding on territories of central or peripheral colony location. We also assessed the oxidative stress status of a sub-sample of central vs. peripheral chick-brooders to determine whether chronic stress arose from breeding on specific territories. On average, we found that brooders had 55% higher CORT levels than incubators. Regardless of breeding status, central birds experienced greater social density (higher number of neighbours, shorter distance between territories) and had higher CORT levels than peripheral birds. Increasing social density positively explained 40% of the variation in CORT levels of both incubators and brooders, but the effect was more pronounced in brooders. In contrast, climate was similar among breeding territories and did not significantly affect the CORT levels of breeding birds. In brooders, oxidative stress status was not affected by local density or weather conditions. These results highlight that local heterogeneity in breeding (including social) conditions may strongly affect the stress levels of breeding seabirds. The fitness consequences of such variation remain to be investigated.

  20. Effects of white matter microstructure on phase and susceptibility maps.

    Science.gov (United States)

    Wharton, Samuel; Bowtell, Richard

    2015-03-01

    To investigate the effects on quantitative susceptibility mapping (QSM) and susceptibility tensor imaging (STI) of the frequency variation produced by the microstructure of white matter (WM). The frequency offsets in a WM tissue sample that are not explained by the effect of bulk isotropic or anisotropic magnetic susceptibility, but rather result from the local microstructure, were characterized for the first time. QSM and STI were then applied to simulated frequency maps that were calculated using a digitized whole-brain, WM model formed from anatomical and diffusion tensor imaging data acquired from a volunteer. In this model, the magnitudes of the frequency contributions due to anisotropy and microstructure were derived from the results of the tissue experiments. The simulations suggest that the frequency contribution of microstructure is much larger than that due to bulk effects of anisotropic magnetic susceptibility. In QSM, the microstructure contribution introduced artificial WM heterogeneity. For the STI processing, the microstructure contribution caused the susceptibility anisotropy to be significantly overestimated. Microstructure-related phase offsets in WM yield artifacts in the calculated susceptibility maps. If susceptibility mapping is to become a robust MRI technique, further research should be carried out to reduce the confounding effects of microstructure-related frequency contributions. © 2014 Wiley Periodicals, Inc.

  1. Low bone mineral density is not related to failure in femoral neck fracture patients treated with internal fixation

    DEFF Research Database (Denmark)

    Viberg, Bjarke; Ryg, Jesper; Overgaard, Søren

    2014-01-01

    the importance of low bone mineral density (BMD). Patients and methods - 140 consecutive patients (105 females, median age 80) treated with IF had a dual-energy X-ray absorptiometry (DXA) scan of the hip performed median 80 days after treatment. The patients' radiographs were evaluated for fracture displacement......, implant positioning, and quality of reduction. From a questionnaire completed during admission, 2 variables for comorbidity and walking disability were chosen. Primary outcome was low hip BMD (amount of mineral matter per square centimeter of hip bone) compared to hip failure (resection, arthroplasty...

  2. Additive manufacturing of metals: a brief review of the characteristic microstructures and properties of steels, Ti-6Al-4V and high-entropy alloys

    Science.gov (United States)

    Gorsse, Stéphane; Hutchinson, Christopher; Gouné, Mohamed; Banerjee, Rajarshi

    2017-01-01

    Abstract We present a brief review of the microstructures and mechanical properties of selected metallic alloys processed by additive manufacturing (AM). Three different alloys, covering a large range of technology readiness levels, are selected to illustrate particular microstructural features developed by AM and clarify the engineering paradigm relating process–microstructure–property. With Ti-6Al-4V the emphasis is placed on the formation of metallurgical defects and microstructures induced by AM and their role on mechanical properties. The effects of the large in-built dislocation density, surface roughness and build atmosphere on mechanical and damage properties are discussed using steels. The impact of rapid solidification inherent to AM on phase selection is highlighted for high-entropy alloys. Using property maps, published mechanical properties of additive manufactured alloys are graphically summarized and compared to conventionally processed counterparts. PMID:28970868

  3. Non-linear effects of initial melt temperatures on microstructures and mechanical properties during quenching process of liquid Cu{sub 46}Zr{sub 54} alloy

    Energy Technology Data Exchange (ETDEWEB)

    Mo, Yun-Fei [School of Physics and Microelectronics Science, Hunan University, Changsha, 410082 (China); Liu, Rang-Su, E-mail: liurangsu@sina.com [School of Physics and Microelectronics Science, Hunan University, Changsha, 410082 (China); Tian, Ze-An; Liang, Yong-Chao [School of Physics and Microelectronics Science, Hunan University, Changsha, 410082 (China); Zhang, Hai-Tao [School of Physics and Microelectronics Science, Hunan University, Changsha, 410082 (China); Department of Electronic and Communication Engineering, Changsha University, Changsha 410003 (China); Hou, Zhao-Yang [Department of Applied Physics, Chang’an University, Xi’an 710064 (China); Liu, Hai-Rong [College of Materials Science and Engineering, Hunan University, Changsha 410082 (China); Zhang, Ai-long [College of Physics and Electronics, Hunan University of Arts and Science, Changde 415000 (China); Zhou, Li-Li [Department of Information Engineering, Gannan Medical University, Ganzhou 341000 (China); Peng, Ping [College of Materials Science and Engineering, Hunan University, Changsha 410082 (China); Xie, Zhong [School of Physics and Microelectronics Science, Hunan University, Changsha, 410082 (China)

    2015-05-15

    A MD simulation of liquid Cu{sub 46}Zr{sub 54} alloys has been performed for understanding the effects of initial melt temperatures on the microstructural evolution and mechanical properties during quenching process. By using several microstructural analyzing methods, it is found that the icosahedral and defective icosahedral clusters play a key role in the microstructure transition. All the final solidification structures obtained at different initial melt temperatures are of amorphous structures, and their structural and mechanical properties are non-linearly related to the initial melt temperatures, and fluctuated in a certain range. Especially, there exists a best initial melt temperature, from which the glass configuration possesses the highest packing density, the optimal elastic constants, and the smaller extent of structural softening under deforming.

  4. Connectivity Measures in EEG Microstructural Sleep Elements.

    Science.gov (United States)

    Sakellariou, Dimitris; Koupparis, Andreas M; Kokkinos, Vasileios; Koutroumanidis, Michalis; Kostopoulos, George K

    2016-01-01

    During Non-Rapid Eye Movement sleep (NREM) the brain is relatively disconnected from the environment, while connectedness between brain areas is also decreased. Evidence indicates, that these dynamic connectivity changes are delivered by microstructural elements of sleep: short periods of environmental stimuli evaluation followed by sleep promoting procedures. The connectivity patterns of the latter, among other aspects of sleep microstructure, are still to be fully elucidated. We suggest here a methodology for the assessment and investigation of the connectivity patterns of EEG microstructural elements, such as sleep spindles. The methodology combines techniques in the preprocessing, estimation, error assessing and visualization of results levels in order to allow the detailed examination of the connectivity aspects (levels and directionality of information flow) over frequency and time with notable resolution, while dealing with the volume conduction and EEG reference assessment. The high temporal and frequency resolution of the methodology will allow the association between the microelements and the dynamically forming networks that characterize them, and consequently possibly reveal aspects of the EEG microstructure. The proposed methodology is initially tested on artificially generated signals for proof of concept and subsequently applied to real EEG recordings via a custom built MATLAB-based tool developed for such studies. Preliminary results from 843 fast sleep spindles recorded in whole night sleep of 5 healthy volunteers indicate a prevailing pattern of interactions between centroparietal and frontal regions. We demonstrate hereby, an opening to our knowledge attempt to estimate the scalp EEG connectivity that characterizes fast sleep spindles via an "EEG-element connectivity" methodology we propose. The application of the latter, via a computational tool we developed suggests it is able to investigate the connectivity patterns related to the occurrence

  5. Relative power density distribution calculations of the Kori unit 1 pressurized water reactor with full-scope explicit modeling of monte carlo simulation

    International Nuclear Information System (INIS)

    Kim, J. O.; Kim, J. K.

    1997-01-01

    Relative power density distributions of the Kori unit 1 pressurized water reactor calculated by Monte Carlo modeling with the MCNP code. The Kori unit 1 core is modeled on a three-dimensional representation of the one-eighth of the reactor in-vessel component with reflective boundaries at 0 and 45 degrees. The axial core model is based on half core symmetry and is divided into four axial segments. Fission reaction density in each rod is calculated by following 100 cycles with 5,000 test neutrons in each cycle after starting with a localized neutron source and ten noncontributing settle cycles. Relative assembly power distributions are calculated from fission reaction densities of rods in assembly. After 100 cycle calculations, the system coverages to a κ value of 1.00039 ≥ 0.00084. Relative assembly power distribution is nearly the same with that of the Kori unit 1 FSAR. Applicability of the full-scope Monte Carlo simulation in the power distribution calculation is examined by the relative root mean square error of 2.159%. (author)

  6. Blood pressure of urban school children in relation to road-traffic noise, traffic density and presence of public transport.

    Science.gov (United States)

    Paunovic, Katarina; Belojevic, Goran; Jakovljevic, Branko

    2013-01-01

    The aim of the study was to investigate the relationship between noise levels, traffic density and the presence of public transport and children's blood pressure. Another aim was to assess the applicability of public transport as a proxy indicator of noise exposure. A cross-sectional study involved 1113 children aged 7-11 years from a central municipality in Belgrade. Equivalent noise levels were measured in front of all schools and in the middle of all streets. Traffic density was defined as number of light and heavy vehicles per hour. The number of public transport vehicles was calculated from official timetables. Children's addresses were matched with noise levels and transport maps. A physician measured blood pressure with the sphygmomanometer. Children attending schools with public transport running nearby had by 1.3 mmHg higher systolic pressure than did children from schools without public transport. This relationship was independent from children's age, gender, and body mass index, family history of hypertension, some dwelling characteristics, and lifestyle habits. The association between diastolic pressure and public transport was statistically insignificant. The study indicated a possible positive association between the presence of public transport in the vicinity of schools with systolic blood pressure in 7-11 year-old schoolchildren. The presence of public transport may serve as an auxiliary indicator of noise exposure in undeveloped countries with limited capacities for noise measurement or modeling.

  7. A high-density linkage map and QTL mapping of fruit-related traits in pumpkin (Cucurbita moschata Duch.).

    Science.gov (United States)

    Zhong, Yu-Juan; Zhou, Yang-Yang; Li, Jun-Xing; Yu, Ting; Wu, Ting-Quan; Luo, Jian-Ning; Luo, Shao-Bo; Huang, He-Xun

    2017-10-06

    Pumpkin (Cucurbita moschata) is an economically worldwide crop. Few quantitative trait loci (QTLs) were reported previously due to the lack of genomic and genetic resources. In this study, a high-density linkage map of C. moschata was structured by double-digest restriction site-associated DNA sequencing, using 200 F2 individuals of CMO-1 × CMO-97. By filtering 74,899 SNPs, a total of 3,470 high quality SNP markers were assigned to the map spanning a total genetic distance of 3087.03 cM on 20 linkage groups (LGs) with an average genetic distance of 0.89 cM. Based on this map, both pericarp color and strip were fined mapped to a novel single locus on LG8 in the same region of 0.31 cM with phenotypic variance explained (PVE) of 93.6% and 90.2%, respectively. QTL analysis was also performed on carotenoids, sugars, tuberculate fruit, fruit diameter, thickness and chamber width with a total of 12 traits. 29 QTLs distributed in 9 LGs were detected with PVE from 9.6% to 28.6%. It was the first high-density linkage SNP map for C. moschata which was proved to be a valuable tool for gene or QTL mapping. This information will serve as significant basis for map-based gene cloning, draft genome assembling and molecular breeding.

  8. The role of cone-beam breast-CT for breast cancer detection relative to breast density.

    Science.gov (United States)

    Wienbeck, Susanne; Uhlig, Johannes; Luftner-Nagel, Susanne; Zapf, Antonia; Surov, Alexey; von Fintel, Eva; Stahnke, Vera; Lotz, Joachim; Fischer, Uwe

    2017-12-01

    To evaluate the impact of breast density on the diagnostic accuracy of non-contrast cone-beam breast computed tomography (CBBCT) in comparison to mammography for the detection of breast masses. A retrospective study was conducted from August 2015 to July 2016. Fifty-nine patients (65 breasts, 112 lesions) with BI-RADS, 5th edition 4 or 5 assessment in mammography and/or ultrasound of the breast received an additional non-contrast CBBCT. Independent double blind reading by two radiologists was performed for mammography and CBBCT imaging. Sensitivity, specificity and AUC were compared between the modalities. Breast lesions were histologically examined in 85 of 112 lesions (76%). The overall sensitivity for CBBCT (reader 1: 91%, reader 2: 88%) was higher than in mammography (both: 68%, pdensity group (pdensity breasts. • Overall sensitivity for non-contrast CBBCT ranged between 88%-91%. • Sensitivity was higher for CBBCT than mammography in both density types (pdensity types (pdensity types (p<0.001).

  9. Significance of oxidized low-density lipoprotein in body fluids as a marker related to diseased conditions.

    Science.gov (United States)

    Itabe, Hiroyuki; Kato, Rina; Sasabe, Naoko; Obama, Takashi; Yamamoto, Matsuo

    2018-03-06

    Oxidatively modified low-density lipoprotein (oxLDL) is known to be involved in various diseases, including cardiovascular diseases. The presence of oxLDL in the human circulatory system and in atherosclerotic lesions has been demonstrated u