WorldWideScience

Sample records for cell packing density

  1. Cell packing structures

    KAUST Repository

    Pottmann, Helmut

    2015-03-03

    This paper is an overview of architectural structures which are either composed of polyhedral cells or closely related to them. We introduce the concept of a support structure of such a polyhedral cell packing. It is formed by planar quads and obtained by connecting corresponding vertices in two combinatorially equivalent meshes whose corresponding edges are coplanar and thus determine planar quads. Since corresponding triangle meshes only yield trivial structures, we focus on support structures associated with quad meshes or hex-dominant meshes. For the quadrilateral case, we provide a short survey of recent research which reveals beautiful relations to discrete differential geometry. Those are essential for successfully initializing numerical optimization schemes for the computation of quad-based support structures. Hex-dominant structures may be designed via Voronoi tessellations, power diagrams, sphere packings and various extensions of these concepts. Apart from the obvious application as load-bearing structures, we illustrate here a new application to shading and indirect lighting. On a higher level, our work emphasizes the interplay between geometry, optimization, statics, and manufacturing, with the overall aim of combining form, function and fabrication into novel integrated design tools.

  2. Optimized Packing Density of Large CZTS Nanoparticles Synthesized by Hot-injection for Thin Film Solar Cells

    DEFF Research Database (Denmark)

    Engberg, Sara Lena Josefin; Lam, Yeng Ming; Schou, Jørgen

    processing to be a feasible fabrication route in the future, the amount of carbon in the film has to be limited. Today, several methods are employed in order to surpass this barrier, for example ligand exchange. A successful ligand exchange was carried out by Carrete et al. [1], where they replace...... to image the faceted/hexagonal nanoparticles and determine their individual composition. Densification of the film will also improve the film-quality. The optimal packing density will be calculated, and size-selective methods can be carried out in order to try to isolate the desired particle sizes. Films...

  3. Packing Density Approach for Sustainable Development of Concrete

    Directory of Open Access Journals (Sweden)

    Sudarshan Dattatraya KORE

    2017-12-01

    Full Text Available This paper deals with the details of optimized mix design for normal strength concrete using particle packing density method. Also the concrete mixes were designed as per BIS: 10262-2009. Different water-cement ratios were used and kept same in both design methods. An attempt has been made to obtain sustainable and cost effective concrete product by use of particle packing density method. The parameters such as workability, compressive strength, cost analysis and carbon di oxide emission were discussed. The results of the study showed that, the compressive strength of the concrete produced by packing density method are closer to that of design compressive strength of BIS code method. By adopting the packing density method for design of concrete mixes, resulted in 11% cost saving with 12% reduction in carbon di oxide emission.

  4. Simulation of random mixed packing of different density particles

    International Nuclear Information System (INIS)

    Yuan-Yuan, Li; Wei, Xia; Zhao-Yao, Zhou; Wen-Zhen, Zhong; Yuan-Biao, Wu; Ke-Jing, He

    2010-01-01

    This paper presents the effects of density difference on the three-dimensional (3D) distribution of random mixed packing. The random mixed packing dynamics of particles of two different densities are simulated. The initial state is homogeneous, but the final packing state is inhomogeneous. The segregation phenomenon (inhomogeneous distribution) is also observed. In the final state, the top layers are composed of mostly light particles. The several layers beneath the top contain more heavy particles than light particles. At the bottom, they also contain more heavy particles than light particles. Furthermore, at both the top and the bottom, particle clustering is observed. The current study also analyses the cause of this inhomogeneity in detail. The main cause of this phenomenon is the velocity difference after collision of these two types of particles induced by the density difference. The present study reveals that even if particles were perfectly mixed, the packing process would lead to the final inhomogeneous mixture. It suggests that special treatment may be required to get the true homogeneous packing. (classical areas of phenomenology)

  5. Effect of particle shape on the random packing density of amorphous solids

    NARCIS (Netherlands)

    Kyrylyuk, A.V.|info:eu-repo/dai/nl/269067590; Philipse, A.P.|info:eu-repo/dai/nl/073532894

    2011-01-01

    The packing density of a particulate solid strongly depends on the shape of the particles that are jammed at random close packing (RCP). To investigate the effect of particle shape on the RCP density of an amorphous solid, we studied jammed packings of binary mixtures of a-thermal or granular

  6. Packing density of rigid aggregates is independent of scale.

    Science.gov (United States)

    Zangmeister, Christopher D; Radney, James G; Dockery, Lance T; Young, Jessica T; Ma, Xiaofei; You, Rian; Zachariah, Michael R

    2014-06-24

    Large planetary seedlings, comets, microscale pharmaceuticals, and nanoscale soot particles are made from rigid, aggregated subunits that are compacted under low compression into larger structures spanning over 10 orders of magnitude in dimensional space. Here, we demonstrate that the packing density (θf) of compacted rigid aggregates is independent of spatial scale for systems under weak compaction. The θf of rigid aggregated structures across six orders of magnitude were measured using nanoscale spherical soot aerosol composed of aggregates with ∼ 17-nm monomeric subunits and aggregates made from uniform monomeric 6-mm spherical subunits at the macroscale. We find θf = 0.36 ± 0.02 at both dimensions. These values are remarkably similar to θf observed for comet nuclei and measured values of other rigid aggregated systems across a wide variety of spatial and formative conditions. We present a packing model that incorporates the aggregate morphology and show that θf is independent of both monomer and aggregate size. These observations suggest that the θf of rigid aggregates subject to weak compaction forces is independent of spatial dimension across varied formative conditions.

  7. Disordered strictly jammed binary sphere packings attain an anomalously large range of densities

    Science.gov (United States)

    Hopkins, Adam B.; Stillinger, Frank H.; Torquato, Salvatore

    2013-08-01

    Previous attempts to simulate disordered binary sphere packings have been limited in producing mechanically stable, isostatic packings across a broad spectrum of packing fractions. Here we report that disordered strictly jammed binary packings (packings that remain mechanically stable under general shear deformations and compressions) can be produced with an anomalously large range of average packing fractions 0.634≤ϕ≤0.829 for small to large sphere radius ratios α restricted to α≥0.100. Surprisingly, this range of average packing fractions is obtained for packings containing a subset of spheres (called the backbone) that are exactly strictly jammed, exactly isostatic, and also generated from random initial conditions. Additionally, the average packing fractions of these packings at certain α and small sphere relative number concentrations x approach those of the corresponding densest known ordered packings. These findings suggest for entropic reasons that these high-density disordered packings should be good glass formers and that they may be easy to prepare experimentally. We also identify an unusual feature of the packing fraction of jammed backbones (packings with rattlers excluded). The backbone packing fraction is about 0.624 over the majority of the α-x plane, even when large numbers of small spheres are present in the backbone. Over the (relatively small) area of the α-x plane where the backbone is not roughly constant, we find that backbone packing fractions range from about 0.606 to 0.829, with the volume of rattler spheres comprising between 1.6% and 26.9% of total sphere volume. To generate isostatic strictly jammed packings, we use an implementation of the Torquato-Jiao sequential linear programming algorithm [Phys. Rev. EPLEEE81539-375510.1103/PhysRevE.82.061302 82, 061302 (2010)], which is an efficient producer of inherent structures (mechanically stable configurations at the local maxima in the density landscape). The identification and

  8. Disordered strictly jammed binary sphere packings attain an anomalously large range of densities.

    Science.gov (United States)

    Hopkins, Adam B; Stillinger, Frank H; Torquato, Salvatore

    2013-08-01

    Previous attempts to simulate disordered binary sphere packings have been limited in producing mechanically stable, isostatic packings across a broad spectrum of packing fractions. Here we report that disordered strictly jammed binary packings (packings that remain mechanically stable under general shear deformations and compressions) can be produced with an anomalously large range of average packing fractions 0.634≤φ≤0.829 for small to large sphere radius ratios α restricted to α≥0.100. Surprisingly, this range of average packing fractions is obtained for packings containing a subset of spheres (called the backbone) that are exactly strictly jammed, exactly isostatic, and also generated from random initial conditions. Additionally, the average packing fractions of these packings at certain α and small sphere relative number concentrations x approach those of the corresponding densest known ordered packings. These findings suggest for entropic reasons that these high-density disordered packings should be good glass formers and that they may be easy to prepare experimentally. We also identify an unusual feature of the packing fraction of jammed backbones (packings with rattlers excluded). The backbone packing fraction is about 0.624 over the majority of the α-x plane, even when large numbers of small spheres are present in the backbone. Over the (relatively small) area of the α-x plane where the backbone is not roughly constant, we find that backbone packing fractions range from about 0.606 to 0.829, with the volume of rattler spheres comprising between 1.6% and 26.9% of total sphere volume. To generate isostatic strictly jammed packings, we use an implementation of the Torquato-Jiao sequential linear programming algorithm [Phys. Rev. E 82, 061302 (2010)], which is an efficient producer of inherent structures (mechanically stable configurations at the local maxima in the density landscape). The identification and explicit construction of binary packings

  9. Packing density of rigid aggregates is independent of scale

    OpenAIRE

    Zangmeister, Christopher D.; Radney, James G.; Dockery, Lance T.; Young, Jessica T.; Ma, Xiaofei; You, Rian; Zachariah, Michael R.

    2014-01-01

    Particle aggregates are one of the most ubiquitous structural arrangements in the universe, making up large interstellar planetary seedlings and comets, microscale powdered pharmaceuticals, and nanoscale atmospheric particles. The packing of aggregates determines structure and, in many cases, chemical, physical, and mechanical properties. Here we show that packing in weakly compacted aggregated materials is scale invariant over many orders of magnitude. We demonstrate that the effective densi...

  10. Improved Erythrocyte Osmotic Fragility and Packed Cell Volume ...

    African Journals Online (AJOL)

    Improved Erythrocyte Osmotic Fragility and Packed Cell Volume following administration of Aloe barbadensis Juice Extract in Rats. ... Abstract. Aloe barbadensis is a popular house plant that has a long history of a multipurpose folk remedy. ... Keywords: osmotic fragility, packed cell volume, haemoglobin, Aloe vera ...

  11. High Efficiency, High Density Terrestrial Panel. [for solar cell modules

    Science.gov (United States)

    Wohlgemuth, J.; Wihl, M.; Rosenfield, T.

    1979-01-01

    Terrestrial panels were fabricated using rectangular cells. Packing densities in excess of 90% with panel conversion efficiencies greater than 13% were obtained. Higher density panels can be produced on a cost competitive basis with the standard salami panels.

  12. Effect of particle shape on the density and microstructure of random packings

    International Nuclear Information System (INIS)

    Wouterse, Alan; Williams, Stephen R; Philipse, Albert P

    2007-01-01

    We study the random packing of non-spherical particles by computer simulation to investigate the effect of particle shape and aspect ratio on packing density and microstructure. Packings of cut spheres (a spherical segment which is symmetric about the centre of the sphere) are simulated to assess the influence of a planar face on packing properties. It turns out that cut spheres, in common with spherocylinders and spheroids, pack more efficiently as the particle's aspect ratio is perturbed slightly from unity (the aspect ratio of a sphere) to reach a maximum density at an aspect ratio of approximately 1.25. Upon increasing the aspect ratio further the cut spheres pack less efficiently, until approximately an aspect ratio of 2, where the particles are found to form a columnar phase. The amount of ordering is sensitive to simulation parameters and for very thin disks the formation of long columns becomes frustrated, resulting in a nematic phase, in marked contrast to the behavior of long thin rods which always randomly pack into entangled isotropic networks. With respect to coordination numbers it appears that cut spheres always pack with significantly fewer contacts than required for isostatic packing

  13. Qualitative Observations Concerning Packing Densities for Liquids, Solutions, and Random Assemblies of Spheres

    Science.gov (United States)

    Duer, W. C.; And Others

    1977-01-01

    Discusses comparisons of packing densities derived from known molar volume data of liquids and solutions. Suggests further studies for using assemblies of spheres as models for simple liquids and solutions. (MLH)

  14. Fast charge implications: Pack and cell analysis and comparison

    Science.gov (United States)

    Tanim, Tanvir R.; Shirk, Matthew G.; Bewley, Randy L.; Dufek, Eric J.; Liaw, Bor Yann

    2018-03-01

    This study investigates the effect of 50-kW (about 2C) direct current fast charging on a full-size battery electric vehicle's battery pack in comparison to a pack exclusively charged at 3.3 kW, which is the common alternating current Level 2 charging power level. Comparable scaled charging protocols are also independently applied to individual cells at three different temperatures, 20 °C, 30 °C, and 40 °C, to perform a comparative analysis with the packs. Dominant cell-level aging modes were identified through incremental capacity analysis and compared with full packs to gain a clear understanding of additional key factors that affect pack aging. While the cell-level study showed a minor impact on performance due to direct current fast charging, the packs showed a significantly higher rate of capacity fade under similar charging protocols. This indicates that pack-level aging cannot be directly extrapolated from cell evaluation. Delayed fast charging, completing shortly before discharge, was found to have less of an impact on battery degradation than conventional alternating current Level 2 charging.

  15. Fire Tests on E-vehicle Battery Cells and Packs.

    Science.gov (United States)

    Sturk, David; Hoffmann, Lars; Ahlberg Tidblad, Annika

    2015-01-01

    The purpose of this study was to investigate the effects of abuse conditions, including realistic crash scenarios, on Li ion battery systems in E-vehicles in order to develop safe practices and priorities when responding to accidents involving E-vehicles. External fire tests using a single burning item equipment were performed on commercial Li ion battery cells and battery packs for electric vehicle (E-vehicle) application. The 2 most common battery cell technologies were tested: Lithium iron phosphate (LFP) and mixed transition metal oxide (lithium nickel manganese cobalt oxide, NMC) cathodes against graphite anodes, respectively. The cell types investigated were "pouch" cells, with similar physical dimensions, but the NMC cells have double the electric capacity of the LFP cells due to the higher energy density of the NMC chemistry, 7 and 14 Ah, respectively. Heat release rate (HRR) data and concentrations of toxic gases were acquired by oxygen consumption calorimetry and Fourier transform infrared spectroscopy (FTIR), respectively. The test results indicate that the state of charge (SOC) affects the HRR as well as the amount of toxic hydrogen fluoride (HF) gas formed during combustion. A larger number of cells increases the amount of HF formed per cell. There are significant differences in response to the fire exposure between the NMC and LFP cells in this study. The LFP cells generate a lot more HF per cell, but the overall reactivity of the NMC cells is higher. However, the total energy released by both batteries during combustion was independent of SOC, which indicates that the electric energy content of the test object contributes to the activation energy of the thermal and heat release process, whereas the chemical energy stored in the materials is the main source of thermal energy in the batteries. The results imply that it is difficult to draw conclusions about higher order system behavior with respect to HF emissions based on data from tests on single

  16. Influence of particle packing density on the rheology of low cement content concrete

    NARCIS (Netherlands)

    Fennis-Huijben, S.A.A.M.; Grunewald, S.; Walraven, J.C.; Den Uijl, J.A.

    2012-01-01

    Optimizing concrete mixtures with regard to cement content is one of the most important solutions in sustainable concrete design. Workability o f these low cement content or ecological mixtures is very important. Eleven mortar mixtures are presented, which show how a higher packing density can be

  17. Expected packing density allows prediction of both amyloidogenic and disordered regions in protein chains

    International Nuclear Information System (INIS)

    Galzitskaya, Oxana V; Garbuzynskiy, Sergiy O; Lobanov, Michail Yu

    2007-01-01

    The determination of factors that influence conformational changes in proteins is very important for the identification of potentially amyloidogenic and disordered regions in polypeptide chains. In our work we introduce a new parameter, mean packing density, to detect both amyloidogenic and disordered regions in a protein sequence. It has been shown that regions with strong expected packing density are responsible for amyloid formation. Our predictions are consistent with known disease-related amyloidogenic regions for 9 of 12 amyloid-forming proteins and peptides in which the positions of amyloidogenic regions have been revealed experimentally. Our findings support the concept that the mechanism of formation of amyloid fibrils is similar for different peptides and proteins. Moreover, we have demonstrated that regions with weak expected packing density are responsible for the appearance of disordered regions. Our method has been tested on datasets of globular proteins and long disordered protein segments, and it shows improved performance over other widely used methods. Thus, we demonstrate that the expected packing density is a useful value for predicting both disordered and amyloidogenic regions of a protein based on sequence alone. Our results are important for understanding the structural characteristics of protein folding and misfolding

  18. Effects on Packed Cell Volume and Parasitic Worm Load from ...

    African Journals Online (AJOL)

    Their packed cell volumes were estimated with centrifuge hematocrit and stool examined for parasitic worms with saline wet prep microscopy. A dose of Albendazole was administered to the study group. The data presented in Microsoft Excel spread sheet, were then analysed using SPSS version 17, T-test and Chi Square ...

  19. Improved Erythrocyte Osmotic Fragility and Packed Cell Volume ...

    African Journals Online (AJOL)

    Aloe barbadensis is a popular house plant that has a long history of a multipurpose folk remedy. It has been documented to have anti-diabetic, antiseptic and anti-inflammatory effects. The effect of Aloe barbadensis juice extract on erythrocyte osmotic fragility, packed cell volume and haemoglobin concentration in Wistar rats ...

  20. Parasites and associated packed cell volume changes of captive ...

    African Journals Online (AJOL)

    Parasites and associated packed cell volume changes of captive wild birds in the semi-arid region of north-eastern Nigeria. ... Eimeria oocysts (19.8%) were the most prevalent followed respectively by strongyle (7.9%), Ascaridia galli (4.8%) and Raillietina (1.6%) eggs. Egg and oocyst counts were generally low. Necropsy ...

  1. Levels Of Haemoglobin And Packed Cell Volumes In Umbilical Cord ...

    African Journals Online (AJOL)

    The Hb concentration was determined by the indirect colorimetric method, and the PCV by the microhaematocrit centrifuge method. The mean values obtained were Hb 12.13 ± 0.11 g/dl and PCV 37.95 ± 0.49%. The mean umbilical cord blood haemoglobin and packed cell volumes were compared with those of the mothers ...

  2. Fabrication of an Antireflective Nanodome Array with High Packing Density for Photovoltaic Applications

    Directory of Open Access Journals (Sweden)

    Jiseok Lim

    2015-01-01

    Full Text Available This paper describes a nanofabrication method for an antireflective nanodome array with high packing density. The master for the close packed nanodome array was fabricated by industrially well-established photolithography and physical vapor deposition processes to realize uniform and defect-free nanostructure in large area. The nanodome array was formed on the surface of a glass plate by a nanoimprinting process using the replicated mold from the master with the aim of reducing the Fresnel reflection of the glass surface. The replication fidelity was verified using scanning electron microscopy and the nanodome structured glass substrate showed ~3% increase in optical transmittance.

  3. Calculating the Maximum Density of the Surface Packing of Ions in Ionic Liquids

    Science.gov (United States)

    Kislenko, S. A.; Moroz, Yu. O.; Karu, K.; Ivaništšev, V. B.; Fedorov, M. V.

    2018-05-01

    The maximum density of monolayer packing on a graphene surface is calculated by means of molecular dynamics (MD) for ions of characteristic size and symmetry: 1-butyl-3-methylimidazolium [BMIM]+, tetrabutylammonium [TBA]+, tetrafluoroborate [BF4]-, dicyanamide [DCA]-, and bis(trifluoromethane) sulfonimide [TFSI]-. The characteristic orientations of ions in a closely packed monolayer are found. It is shown that the formation of a closely packed monolayer is possible for [DCA]- and [BF4]- anions only at surface charges that exceed the limit of the electrochemical stability of the corresponding ionic liquids. For the [TBA]+ cation, a monolayer structure can be observed at the charge of nearly 30 μC/cm2 attainable in electrochemical experiment.

  4. Fuel Cell Shaft Power Pack - Regulering af brændselsceller

    DEFF Research Database (Denmark)

    Andreasen, Søren Juhl

    2009-01-01

    Afsluttende formidling af forskningsresultater i forbindelse med projektet Fuel Cell Shaft Power Pack......Afsluttende formidling af forskningsresultater i forbindelse med projektet Fuel Cell Shaft Power Pack...

  5. Technical factors influencing cone packing density estimates in adaptive optics flood illuminated retinal images.

    Directory of Open Access Journals (Sweden)

    Marco Lombardo

    Full Text Available PURPOSE: To investigate the influence of various technical factors on the variation of cone packing density estimates in adaptive optics flood illuminated retinal images. METHODS: Adaptive optics images of the photoreceptor mosaic were obtained in fifteen healthy subjects. The cone density and Voronoi diagrams were assessed in sampling windows of 320×320 µm, 160×160 µm and 64×64 µm at 1.5 degree temporal and superior eccentricity from the preferred locus of fixation (PRL. The technical factors that have been analyzed included the sampling window size, the corrected retinal magnification factor (RMFcorr, the conversion from radial to linear distance from the PRL, the displacement between the PRL and foveal center and the manual checking of cone identification algorithm. Bland-Altman analysis was used to assess the agreement between cone density estimated within the different sampling window conditions. RESULTS: The cone density declined with decreasing sampling area and data between areas of different size showed low agreement. A high agreement was found between sampling areas of the same size when comparing density calculated with or without using individual RMFcorr. The agreement between cone density measured at radial and linear distances from the PRL and between data referred to the PRL or the foveal center was moderate. The percentage of Voronoi tiles with hexagonal packing arrangement was comparable between sampling areas of different size. The boundary effect, presence of any retinal vessels, and the manual selection of cones missed by the automated identification algorithm were identified as the factors influencing variation of cone packing arrangements in Voronoi diagrams. CONCLUSIONS: The sampling window size is the main technical factor that influences variation of cone density. Clear identification of each cone in the image and the use of a large buffer zone are necessary to minimize factors influencing variation of Voronoi

  6. A Compound Sensor for Simultaneous Measurement of Packing Density and Moisture Content of Silage.

    Science.gov (United States)

    Meng, Delun; Meng, Fanjia; Sun, Wei; Deng, Shuang

    2017-12-28

    Packing density and moisture content are important factors in investigating the ensiling quality. Low packing density is a major cause of loss of sugar content. The moisture content also plays a determinant role in biomass degradation. To comprehensively evaluate the ensiling quality, this study focused on developing a compound sensor. In it, moisture electrodes and strain gauges were embedded into an ASABE Standard small cone for the simultaneous measurements of the penetration resistance (PR) and moisture content (MC) of silage. In order to evaluate the performance of the designed sensor and the theoretical analysis being used, relevant calibration and validation tests were conducted. The determination coefficients are 0.996 and 0.992 for PR calibration and 0.934 for MC calibration. The validation indicated that this measurement technique could determine the packing density and moisture content of the silage simultaneously and eliminate the influence of the friction between the penetration shaft and silage. In this study, we not only design a compound sensor but also provide an alternative way to investigate the ensiling quality which would be useful for further silage research.

  7. Evaluation of high packing density powder X-ray screens by Monte Carlo methods

    Energy Technology Data Exchange (ETDEWEB)

    Liaparinos, P. [Department of Medical Physics, Medical School, University of Patras, 26500 Patras (Greece); Kandarakis, I.; Cavouras, D. [Department of Medical Instruments Technology, Technological Educational Institution of Athens, Ag. Spyridonos Street, Aigaleo, 12210 Athens (Greece); Kalivas, N. [Greek Atomic Energy Commission, 15310 Athens (Greece); Delis, H. [Department of Medical Physics, Medical School, University of Patras, 26500 Patras (Greece); Panayiotakis, G. [Department of Medical Physics, Medical School, University of Patras, 26500 Patras (Greece)], E-mail: panayiot@upatras.gr

    2007-09-21

    Phosphor materials are employed in intensifying screens of both digital and conventional X-ray imaging detectors. High packing density powder screens have been developed (e.g. screens in ceramic form) exhibiting high-resolution and light emission properties, and thus contributing to improved image transfer characteristics and higher radiation to light conversion efficiency. For the present study, a custom Monte Carlo simulation program was used in order to examine the performance of ceramic powder screens, under various radiographic conditions. The model was developed using Mie scattering theory for the description of light interactions, based on the physical characteristics (e.g. complex refractive index, light wavelength) of the phosphor material. Monte Carlo simulations were carried out assuming: (a) X-ray photon energy ranging from 18 up to 49 keV, (b) Gd{sub 2}O{sub 2}S:Tb phosphor material with packing density of 70% and grain size of 7 {mu}m and (c) phosphor thickness ranging between 30 and 70 mg/cm{sup 2}. The variation of the Modulation Transfer Function (MTF) and the Luminescence Efficiency (LE) with respect to the X-ray energy and the phosphor thickness was evaluated. Both aforementioned imaging characteristics were shown to take high values at 49 keV X-ray energy and 70 mg/cm{sup 2} phosphor thickness. It was found that high packing density screens may be appropriate for use in medical radiographic systems.

  8. Evaluation of high packing density powder X-ray screens by Monte Carlo methods

    Science.gov (United States)

    Liaparinos, P.; Kandarakis, I.; Cavouras, D.; Kalivas, N.; Delis, H.; Panayiotakis, G.

    2007-09-01

    Phosphor materials are employed in intensifying screens of both digital and conventional X-ray imaging detectors. High packing density powder screens have been developed (e.g. screens in ceramic form) exhibiting high-resolution and light emission properties, and thus contributing to improved image transfer characteristics and higher radiation to light conversion efficiency. For the present study, a custom Monte Carlo simulation program was used in order to examine the performance of ceramic powder screens, under various radiographic conditions. The model was developed using Mie scattering theory for the description of light interactions, based on the physical characteristics (e.g. complex refractive index, light wavelength) of the phosphor material. Monte Carlo simulations were carried out assuming: (a) X-ray photon energy ranging from 18 up to 49 keV, (b) Gd 2O 2S:Tb phosphor material with packing density of 70% and grain size of 7 μm and (c) phosphor thickness ranging between 30 and 70 mg/cm 2. The variation of the Modulation Transfer Function (MTF) and the Luminescence Efficiency (LE) with respect to the X-ray energy and the phosphor thickness was evaluated. Both aforementioned imaging characteristics were shown to take high values at 49 keV X-ray energy and 70 mg/cm 2 phosphor thickness. It was found that high packing density screens may be appropriate for use in medical radiographic systems.

  9. Evaluation of high packing density powder X-ray screens by Monte Carlo methods

    International Nuclear Information System (INIS)

    Liaparinos, P.; Kandarakis, I.; Cavouras, D.; Kalivas, N.; Delis, H.; Panayiotakis, G.

    2007-01-01

    Phosphor materials are employed in intensifying screens of both digital and conventional X-ray imaging detectors. High packing density powder screens have been developed (e.g. screens in ceramic form) exhibiting high-resolution and light emission properties, and thus contributing to improved image transfer characteristics and higher radiation to light conversion efficiency. For the present study, a custom Monte Carlo simulation program was used in order to examine the performance of ceramic powder screens, under various radiographic conditions. The model was developed using Mie scattering theory for the description of light interactions, based on the physical characteristics (e.g. complex refractive index, light wavelength) of the phosphor material. Monte Carlo simulations were carried out assuming: (a) X-ray photon energy ranging from 18 up to 49 keV, (b) Gd 2 O 2 S:Tb phosphor material with packing density of 70% and grain size of 7 μm and (c) phosphor thickness ranging between 30 and 70 mg/cm 2 . The variation of the Modulation Transfer Function (MTF) and the Luminescence Efficiency (LE) with respect to the X-ray energy and the phosphor thickness was evaluated. Both aforementioned imaging characteristics were shown to take high values at 49 keV X-ray energy and 70 mg/cm 2 phosphor thickness. It was found that high packing density screens may be appropriate for use in medical radiographic systems

  10. From Global Stresses to Local Cell Packing During Development

    Science.gov (United States)

    Lubensky, David

    2011-03-01

    To perform their functions, cells in epithelial tissues must often adopt highly regular packings. It is still not fully understood how these ordered arrangements of cells arise from disordered, proliferative epithelia during development. I will use experimental and theoretical studies on an attractive model system, the cone cell mosaic in fish retina, to illustrate some ways that mechanical forces and cell signaling can interact to produce this transformation. Experiments examining the response to surgical lesions suggest that the correct mechanical environment at the tissue scale is essential to induce cone cells to rearrange into a rectangular lattice. Starting from this observation, I will argue that large-scale mechanical stresses naturally couple to and orient cell polarization and that this coupling can lead cells to line up in regular rows, as observed in the fish retina. This model predicts that cells in the rows will adopt characteristic trapezoidal shapes and that fragments of rows will persist even in tissue where the mosaic pattern is disrupted by lesions; these predictions are borne out by an analysis of cell packings at the level of the zonula occludens in wildtype and lesioned retinas. Supported by NSF grant IOS-0952873.

  11. Density functional theory analysis of hexagonal close-packed elemental metal photocathodes

    Directory of Open Access Journals (Sweden)

    Tuo Li

    2015-07-01

    Full Text Available A density function theory based analysis of photoemission from hexagonal close packed (hcp metals is presented and the calculated values of the rms transverse momentum (Δp_{T} are in good agreement with the available experimental data on Be [Phys. Rev. Lett. 111, 237401 (2013] and Mg [Proceedings of LINAC 2002, Gyeongju, Korea (2002]. The lattice constants and work functions of the hcp metals are also examined and are consistent with the available experimental values. In addition, emission from (0001-oriented Be is examined due to the presence of a strong surface state.

  12. Development and use of pediatric frozen red cell packs.

    Science.gov (United States)

    Staples, J W; Fritz, G E

    1976-01-01

    Repeated transfusion of small increments of blood are frequently required for the sick and premature newborn infant to correct endogenous hypovolemia and/or to replace blood obtained for laboratory monitoring purposes. Previously fresh group and type specific whole blood was used. To eliminate waste of fresh whole blood, maintain fresh red blood cell properties, eliminate the hazards of transfusing plasma and to provide a more efficient system, a pediatric frozen red cell pack (PFRCP) has been developed. Units of group O rr red blood cells are glycerolized using a high glycerol method. The glycerolized red blood cells are separated into three equal aliquots and frozen. When needed, the PFRCP are deglycerolized by a modified procedure using the IBM Cell Processor. During a six month period, 71 infants were given 153 separate transfusions of deglycerolized red blood cells using 102 PFRCP prepared from 34 units of red blood cells. Red blood cell recovery, hematocrit, white blood cell removal, residual glycerol, total protein, and supernatant hemoglobin levels were measured. Clinical response was followed and found to be excellent.

  13. Measuring single-cell density.

    Science.gov (United States)

    Grover, William H; Bryan, Andrea K; Diez-Silva, Monica; Suresh, Subra; Higgins, John M; Manalis, Scott R

    2011-07-05

    We have used a microfluidic mass sensor to measure the density of single living cells. By weighing each cell in two fluids of different densities, our technique measures the single-cell mass, volume, and density of approximately 500 cells per hour with a density precision of 0.001 g mL(-1). We observe that the intrinsic cell-to-cell variation in density is nearly 100-fold smaller than the mass or volume variation. As a result, we can measure changes in cell density indicative of cellular processes that would be otherwise undetectable by mass or volume measurements. Here, we demonstrate this with four examples: identifying Plasmodium falciparum malaria-infected erythrocytes in a culture, distinguishing transfused blood cells from a patient's own blood, identifying irreversibly sickled cells in a sickle cell patient, and identifying leukemia cells in the early stages of responding to a drug treatment. These demonstrations suggest that the ability to measure single-cell density will provide valuable insights into cell state for a wide range of biological processes.

  14. Packed bed bioreactor with porous ceramic beads for animal cell culture.

    Science.gov (United States)

    Park, S; Stephanopoulos, G

    1993-01-05

    A packed bed bioreactor was investigated as means for the cultivation of mammalian cells. The packed bed is comprised of porous ceramic particles with pores sufficiently large for cell immobilization as well as for intraparticle convective flow. In this way, the transport of limiting nutrients such as oxygen can be significantly enhanced, allowing maintenance of cell viability and productivity in an environment protective of adverse shear effects. The extent of intraparticle convective medium flow was experimentally quantified relative to the reactor operating conditions, and was found to be the dominant mechanism of nutrient transport to cells immobilized in the particle interior. An approximate linear relationship was obtained between overall reactor productivity and the extent of intraparticle convection. As the latter can be controlled at the single-particle level through total flow rate control, this relationship is a useful scale-up tool for the design of bioreactors. The high cell densities and the high volumetric productivities achieved by using small lab-scale reactors underline the potential of this simple bioreactor configuration for large-scale cell culture applications.

  15. Cortical cell and neuron density estimates in one chimpanzee hemisphere.

    Science.gov (United States)

    Collins, Christine E; Turner, Emily C; Sawyer, Eva Kille; Reed, Jamie L; Young, Nicole A; Flaherty, David K; Kaas, Jon H

    2016-01-19

    The density of cells and neurons in the neocortex of many mammals varies across cortical areas and regions. This variability is, perhaps, most pronounced in primates. Nonuniformity in the composition of cortex suggests regions of the cortex have different specializations. Specifically, regions with densely packed neurons contain smaller neurons that are activated by relatively few inputs, thereby preserving information, whereas regions that are less densely packed have larger neurons that have more integrative functions. Here we present the numbers of cells and neurons for 742 discrete locations across the neocortex in a chimpanzee. Using isotropic fractionation and flow fractionation methods for cell and neuron counts, we estimate that neocortex of one hemisphere contains 9.5 billion cells and 3.7 billion neurons. Primary visual cortex occupies 35 cm(2) of surface, 10% of the total, and contains 737 million densely packed neurons, 20% of the total neurons contained within the hemisphere. Other areas of high neuron packing include secondary visual areas, somatosensory cortex, and prefrontal granular cortex. Areas of low levels of neuron packing density include motor and premotor cortex. These values reflect those obtained from more limited samples of cortex in humans and other primates.

  16. Assessment of pack injection cells and the relationship between hematocrit of pack cells and the increase in hematocrit in patients with thalassemia

    OpenAIRE

    Fekri K; Kasiri K; Jalil T; Ganji F

    2017-01-01

    Background and aims: The amount of injected blood in patients with thalassemia is of particular importance and the blood amount is calculated based on the exact volume of pack cell as well as their hematocrit. The aim of this study was to evaluate pack cells and the factors affecting on the amount of their hematocrit and their association with increase in hematocrit after blood injection. Methods: This is descriptive-analytical study. Characteristics including age, size, type of anticoagu...

  17. Modular Approach for Continuous Cell-Level Balancing to Improve Performance of Large Battery Packs: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Muneed ur Rehman, M.; Evzelman, M.; Hathaway, K.; Zane, R.; Plett, G. L.; Smith, K.; Wood, E.; Maksimovic, D.

    2014-10-01

    Energy storage systems require battery cell balancing circuits to avoid divergence of cell state of charge (SOC). A modular approach based on distributed continuous cell-level control is presented that extends the balancing function to higher level pack performance objectives such as improving power capability and increasing pack lifetime. This is achieved by adding DC-DC converters in parallel with cells and using state estimation and control to autonomously bias individual cell SOC and SOC range, forcing healthier cells to be cycled deeper than weaker cells. The result is a pack with improved degradation characteristics and extended lifetime. The modular architecture and control concepts are developed and hardware results are demonstrated for a 91.2-Wh battery pack consisting of four series Li-ion battery cells and four dual active bridge (DAB) bypass DC-DC converters.

  18. Protein dynamics governed by interfaces of high polarity and low packing density.

    Directory of Open Access Journals (Sweden)

    Vladimir Espinosa Angarica

    Full Text Available The folding pathway, three-dimensional structure and intrinsic dynamics of proteins are governed by their amino acid sequences. Internal protein surfaces with physicochemical properties appropriate to modulate conformational fluctuations could play important roles in folding and dynamics. We show here that proteins contain buried interfaces of high polarity and low packing density, coined as LIPs: Light Interfaces of high Polarity, whose physicochemical properties make them unstable. The structures of well-characterized equilibrium and kinetic folding intermediates indicate that the LIPs of the corresponding native proteins fold late and are involved in local unfolding events. Importantly, LIPs can be identified using very fast and uncomplicated computational analysis of protein three-dimensional structures, which provides an easy way to delineate the protein segments involved in dynamics. Since LIPs can be retained while the sequences of the interacting segments diverge significantly, proteins could in principle evolve new functional features reusing pre-existing encoded dynamics. Large-scale identification of LIPS may contribute to understanding evolutionary constraints of proteins and the way protein intrinsic dynamics are encoded.

  19. Impact of Molecular Orientation and Packing Density on Electronic Polarization in the Bulk and at Surfaces of Organic Semiconductors

    KAUST Repository

    Ryno, Sean

    2016-05-16

    The polarizable environment surrounding charge carriers in organic semiconductors impacts the efficiency of the charge transport process. Here, we consider two representative organic semiconductors, tetracene and rubrene, and evaluate their polarization energies in the bulk and at the organic-vacuum interface using a polarizable force field that accounts for induced-dipole and quadrupole interactions. Though both oligoacenes pack in a herringbone motif, the tetraphenyl substituents on the tetracene backbone of rubrene alter greatly the nature of the packing. The resulting change in relative orientations of neighboring molecules is found to reduce the bulk polarization energy of holes in rubrene by some 0.3 eV when compared to tetracene. The consideration of model organic-vacuum interfaces highlights the significant variation in the electrostatic environment for a charge carrier at a surface although the net change in polarization energy is small; interestingly, the environment of a charge even just one layer removed from the surface can be viewed already as representative of the bulk. Overall, it is found that in these herringbone-type layered crystals the polarization energy has a much stronger dependence on the intralayer packing density than interlayer packing density.

  20. Distribution, density, and abundance of pack-ice seals in the Amundsen and Ross Seas, Antarctica

    Science.gov (United States)

    Bengtson, John L.; Laake, Jeff L.; Boveng, Peter L.; Cameron, Michael F.; Bradley Hanson, M.; Stewart, Brent S.

    2011-05-01

    We made three sets of population surveys of the four species of ice-inhabiting phocid pinnipeds in the Ross and Amundsen Seas between 26 December 1999 and 24 March 2000 using icebreakers and helicopters deployed from those icebreakers. We used line transect methods to survey 23,671 km by helicopter and 3,694 km by ship accounting for a total coverage of 53,217 km 2. We detected and identified 11,308 seals in 7,104 groups and estimated their abundance from estimates of densities using distance sampling methods and corrections for probability of haul out of seals derived from satellite telemetry of tagged seals. Crabeater seals were most abundant (ca 1.7 million) followed by Weddell seals (330,000), Ross seals (22,600), and leopard seals (15,000). Our estimates of abundance are difficult to directly compare with earlier estimates because of geographic areas covered and by our improvements in survey and analytical methods. Notwithstanding these limitations and with some adjustments for differences in methods, we found that our estimates of abundance for crabeater seals are similar to those from the most recent surveys in the Ross and Amundsen Seas and along the George-Oates Coast. Our estimates for Weddell seals are the first for the broad areas of pack ice that we surveyed in the Ross and Amundsen Seas but indicate that these habitats are ecologically important to this species. Our estimates of abundance of Ross seals were relatively similar to estimates for surveys in these areas in the 1970s and 1980s whereas our estimates of abundance of leopard seals were substantially lower.

  1. Power generation by packed-bed air-cathode microbial fuel cells

    KAUST Repository

    Zhang, Xiaoyuan

    2013-08-01

    Catalysts and catalyst binders are significant portions of the cost of microbial fuel cell (MFC) cathodes. Many materials have been tested as aqueous cathodes, but air-cathodes are needed to avoid energy demands for water aeration. Packed-bed air-cathodes were constructed without expensive binders or diffusion layers using four inexpensive carbon-based materials. Cathodes made from activated carbon produced the largest maximum power density of 676±93mW/m2, followed by semi-coke (376±47mW/m2), graphite (122±14mW/m2) and carbon felt (60±43mW/m2). Increasing the mass of activated carbon and semi-coke from 5 to ≥15g significantly reduced power generation because of a reduction in oxygen transfer due to a thicker water layer in the cathode (~3 or ~6cm). These results indicate that a thin packed layer of activated carbon or semi-coke can be used to make inexpensive air-cathodes for MFCs. © 2013 Elsevier Ltd.

  2. Effect of Plasmodium species infections on packed cell volume of ...

    African Journals Online (AJOL)

    Populations of exotic and indigenous domestic chickens and guinea fowls in northeastern Nigeria were surveyed for Plasmodium sp by examining their stained blood samples. The packed cel volumes of all blood samples were estimated. During the period of study (March to September 2006), raina data were collected.

  3. Development of a 400 W High Temperature PEM Fuel Cell Power Pack

    DEFF Research Database (Denmark)

    Schaltz, Erik; Jespersen, Jesper Lebæk; Rasmussen, Peter Omand

    2006-01-01

    power pack demonstrates some of the advantages by using a HTPEM fuel cell. This initial system is very simple and there is no need for humidification of the species like in a LTPEM fuel cell system. The use of the HTPEM fuel cell makes it possible to use reformed gas at high CO concentrations without...

  4. Low Density of Top Predators (Seabirds and Marine Mammals in the High Arctic Pack Ice

    Directory of Open Access Journals (Sweden)

    Claude R. Joiris

    2016-01-01

    Full Text Available The at-sea distribution of top predators, seabirds and marine mammals, was determined in the high Arctic pack ice on board the icebreaker RV Polarstern in July to September 2014. In total, 1,620 transect counts were realised, lasting 30 min each. The five most numerous seabird species represented 74% of the total of 15,150 individuals registered: kittiwake Rissa tridactyla, fulmar Fulmarus glacialis, puffin Fratercula arctica, Ross’s gull Rhodostethia rosea, and little auk Alle alle. Eight cetacean species were tallied for a total of 330 individuals, mainly white-beaked dolphin Lagenorhynchus albirostris and fin whale Balaenoptera physalus. Five pinniped species were represented by a total of 55 individuals and the polar bear Ursus maritimus was represented by 12 individuals. Four main geographical zones were identified: from Tromsø to the outer marginal ice zone (OMIZ, the Arctic pack ice (close pack ice, CPI, the end of Lomonosov Ridge off Siberia, and the route off Siberia and northern Norway. Important differences were detected between zones, both in species composition and in individual abundance. Low numbers of species and high proportion of individuals for some of them can be considered to reflect very low biodiversity. Numbers encountered in zones 2 to 4 were very low in comparison with other European Arctic seas. The observed differences showed strong patterns.

  5. Effect of Light and Darkness on Packed Cell Volume in the Rat ...

    African Journals Online (AJOL)

    The aim of the study is to identify and characterize the circadian oscillation of Packed Cell Volume (PCV) within a 24-hour time frame in adult Sprague-Dawley rats. 56 adult Sprague-Dawley rats consists of 28 male and 28 female rats were used. Male animals weighed 150-170g while the females weighed 130140g.

  6. Effect of Vitamin C on the packed cell volume of trypanosome ...

    African Journals Online (AJOL)

    This research was interested in using nutrient in the amelioration of trypanosomiasis which is one of the most endemic diseases of livestock. The study was carried out to evaluate the effect of Vitamin C on the Packed Cell Volume (PCV) of Trypanosoma brucei infected rats. Twenty albino rats (Rattus novegicus) were used.

  7. Effects of 4000 rad irradiation on the in vitro storage properties of packed red cells

    International Nuclear Information System (INIS)

    Moore, G.L.; Ledford, M.E.

    1985-01-01

    Immunosuppressed patients who require red cell transfusions receive irradiated (1500-3000 rad) packed red cells. These cells are irradiated immediately before infusion. If a large group of patients become immunosuppressed due to exposure to radiation or chemicals, the ability to supply large volumes of irradiated blood at the time of use might not be possible. An alternate solution to providing quantities of irradiated blood is to irradiate the units prior to storage. This study presents in vitro data comparing storage of paired packed red cell units either irradiated or not irradiated. Five units of fresh blood drawn into citrate-phosphate-dextrose-adenine (CPDA-1) were packed to a hematocrit of 75 +/- 1 percent, and then each unit was divided in two equal parts. One of each pair was irradiated (4000 rads), and both parts of each unit were stored for 35 days at 4 degrees C. Samples were analyzed every 7 days. Irradiation caused a slight drop in red cell adenosine triphosphate and 2,3 diphosphoglycerate and a slight increase in plasma hemoglobin compared to controls. Methemoglobin, pH, and glucose consumption were identical to the controls. The evidence indicates that irradiation did not cause biochemical or metabolic changes in the red cells that would lead us to suspect a difference between irradiated and nonirradiated stored red cells in function or viability. These negative findings require in vivo confirmation

  8. A power pack based on organometallic perovskite solar cell and supercapacitor.

    Science.gov (United States)

    Xu, Xiaobao; Li, Shaohui; Zhang, Hua; Shen, Yan; Zakeeruddin, Shaik M; Graetzel, Michael; Cheng, Yi-Bing; Wang, Mingkui

    2015-02-24

    We present an investigation on a power pack combining a CH3NH3PbI3-based solar cell with a polypyrrole-based supercapacitor and evaluate its performance as an energy pack. The package achieved an energy storage efficiency of 10%, which is much higher than that of other systems combining a PV cell with a supercapacitor. We find a high output voltage of 1.45 V for the device under AM 1.5G illumination when the CH3NH3PbI3-based solar cell is connected in series with a polypyrrole-based supercapacitor. This system affords continuous output of electric power by using CH3NH3PbI3-based solar cell as an energy source mitigating transients caused by light intensity fluctuations or the diurnal cycle.

  9. Reduction of prion infectivity in packed red blood cells

    International Nuclear Information System (INIS)

    Morales, Rodrigo; Buytaert-Hoefen, Kimberley A.; Gonzalez-Romero, Dennisse; Castilla, Joaquin; Hansen, Eric T.; Hlavinka, Dennis; Goodrich, Raymond P.; Soto, Claudio

    2008-01-01

    The link between a new variant form of Creutzfeldt-Jakob disease (vCJD) and the consumption of prion contaminated cattle meat as well as recent findings showing that vCJD can be transmitted by blood transfusion have raised public health concerns. Currently, a reliable test to identify prions in blood samples is not available. The purpose of this study was to evaluate the possibility to remove scrapie prion protein (PrP Sc ) and infectivity from red blood cell (RBC) suspensions by a simple washing procedure using a cell separation and washing device. The extent of prion removal was assessed by Western blot, PMCA and infectivity bioassays. Our results revealed a substantial removal of infectious prions (≥3 logs of infectivity) by all techniques used. These data suggest that a significant amount of infectivity present in RBC preparations can be removed by a simple washing procedure. This technology may lead to increased safety of blood products and reduce the risk of further propagation of prion diseases.

  10. Evaluation of the red cell hemolysis in packed red cells during processing and storage

    Directory of Open Access Journals (Sweden)

    Makroo R

    2011-01-01

    Full Text Available Introduction : Storage of red cells causes a progressive increase in hemolysis. In spite of the use of additive solutions for storage and filters for leucoreduction, some amount of hemolysis is still inevitable. The extent of hemolysis, however, should not exceed the permissible threshold for hemolysis even on the 42 nd day of storage. Study Design and Methods: Eighty units of packed red cells, 40 stored in SAGM post leucoreduction and 40 in ADSOL without leucoreduction filters, were evaluated for plasma hemoglobin by HemoCue Plasma Hemoglobin analyzer on the day of collection and on the 7 th , 14 th , 21 st , 28 th , 35 th and 42 nd days thereafter. The hemoglobin and hematocrit were also noted for all these units by the Beckman and Coulter analyzer. Percentage hemolysis was then calculated. Observations: Hemolysis progressively increased with the storage period in all the stored red cell units (SAGM as well ADSOL. However, on day 42 nd of storage, free hemoglobin in all the red cell units was within the permissible level (which is 0.8% according to the Council of Europe guidelines and 1% as per the US FDA guidelines. The mean percentage hemolysis was slightly higher in the SAGM-containing bags with an integral leucoreduction filter as compared to the bags containing ADSOL. However this difference was marginal and not statistically significant. Conclusion: Hemolysis of the red cells increases with storage. However, maximum hemolysis does not exceed the permissible limits at any time thereby indicating the effect of optimum processing and storage conditions on red cell hemolysis.

  11. Packed Bed Bioreactor for the Isolation and Expansion of Placental-Derived Mesenchymal Stromal Cells.

    Science.gov (United States)

    Osiecki, Michael J; Michl, Thomas D; Kul Babur, Betul; Kabiri, Mahboubeh; Atkinson, Kerry; Lott, William B; Griesser, Hans J; Doran, Michael R

    2015-01-01

    Large numbers of Mesenchymal stem/stromal cells (MSCs) are required for clinical relevant doses to treat a number of diseases. To economically manufacture these MSCs, an automated bioreactor system will be required. Herein we describe the development of a scalable closed-system, packed bed bioreactor suitable for large-scale MSCs expansion. The packed bed was formed from fused polystyrene pellets that were air plasma treated to endow them with a surface chemistry similar to traditional tissue culture plastic. The packed bed was encased within a gas permeable shell to decouple the medium nutrient supply and gas exchange. This enabled a significant reduction in medium flow rates, thus reducing shear and even facilitating single pass medium exchange. The system was optimised in a small-scale bioreactor format (160 cm2) with murine-derived green fluorescent protein-expressing MSCs, and then scaled-up to a 2800 cm2 format. We demonstrated that placental derived MSCs could be isolated directly within the bioreactor and subsequently expanded. Our results demonstrate that the closed system large-scale packed bed bioreactor is an effective and scalable tool for large-scale isolation and expansion of MSCs.

  12. Determination of mercury in human serum and packed blood cells by neutron activation analysis

    International Nuclear Information System (INIS)

    Versieck, J.; Vanballenberghe, L.; Wittoek, A.; Vermeir, G.; Vandecasteele, C.

    1990-01-01

    A method is described for the determination of mercury in human blood serum and packed blood cells employing neutron activation analysis. Great attention was devoted to the collection and manipulation of the samples. The accuracy and precision of the method were tested by analyzing biological reference materials and by comparing the concentrations measured in a number of serum samples to those obtained by another, independent technique (cold vapor atomic absorption spectrometry) in the same samples. The article reports the levels measured in blood serum and packed blood cells samples from 15 adult volunteers, as well as the figures determined in a open-quotes second-generationclose quotes biological reference material (freeze-dried human serum), prepared and conditioned at the University of Ghent

  13. Power density investigation on the press-pack IGBT 3L-HB-VSCs applied to large wind turbine

    DEFF Research Database (Denmark)

    Senturk, Osman Selcuk; Munk-Nielsen, Stig; Teodorescu, Remus

    2011-01-01

    With three different DC-side and AC-side connections, the three-level H-bridge voltage source converters (3L-HB-VSCs) are alternatives to 3L neutral-point-clamped VSCs (3L-NPC-VSCs) for interfacing large wind turbines with electricity grids. In order to assess their feasibility for large wind...... capabilities, DC capacitor sizes, converter cabinet volumes of the three 3LHB- VSCs utilizing press-pack IGBTs are investigated in order to quantify and compare the power densities of the 3L-HB-VSCs employed as grid-side converters. Also, the suitable transformer types for the 3L-HB-VSCs are determined...... and comparatively studied in terms of volume and weight in order to estimate the size effects of the 3L-HB-VSC topology on the whole wind turbine connection system. Finally, based on the power density and transformer-size investigations, the feasibility of each 3LHB- VSC is discussed....

  14. Virtual modeling of polycrystalline structures of materials using particle packing algorithms and Laguerre cells

    Science.gov (United States)

    Morfa, Carlos Recarey; Farias, Márcio Muniz de; Morales, Irvin Pablo Pérez; Navarra, Eugenio Oñate Ibañez de; Valera, Roberto Roselló

    2017-06-01

    The influence of the microstructural heterogeneities is an important topic in the study of materials. In the context of computational mechanics, it is therefore necessary to generate virtual materials that are statistically equivalent to the microstructure under study, and to connect that geometrical description to the different numerical methods. Herein, the authors present a procedure to model continuous solid polycrystalline materials, such as rocks and metals, preserving their representative statistical grain size distribution. The first phase of the procedure consists of segmenting an image of the material into adjacent polyhedral grains representing the individual crystals. This segmentation allows estimating the grain size distribution, which is used as the input for an advancing front sphere packing algorithm. Finally, Laguerre diagrams are calculated from the obtained sphere packings. The centers of the spheres give the centers of the Laguerre cells, and their radii determine the cells' weights. The cell sizes in the obtained Laguerre diagrams have a distribution similar to that of the grains obtained from the image segmentation. That is why those diagrams are a convenient model of the original crystalline structure. The above-outlined procedure has been used to model real polycrystalline metallic materials. The main difference with previously existing methods lies in the use of a better particle packing algorithm.

  15. Virtual modeling of polycrystalline structures of materials using particle packing algorithms and Laguerre cells

    Science.gov (United States)

    Morfa, Carlos Recarey; Farias, Márcio Muniz de; Morales, Irvin Pablo Pérez; Navarra, Eugenio Oñate Ibañez de; Valera, Roberto Roselló

    2018-04-01

    The influence of the microstructural heterogeneities is an important topic in the study of materials. In the context of computational mechanics, it is therefore necessary to generate virtual materials that are statistically equivalent to the microstructure under study, and to connect that geometrical description to the different numerical methods. Herein, the authors present a procedure to model continuous solid polycrystalline materials, such as rocks and metals, preserving their representative statistical grain size distribution. The first phase of the procedure consists of segmenting an image of the material into adjacent polyhedral grains representing the individual crystals. This segmentation allows estimating the grain size distribution, which is used as the input for an advancing front sphere packing algorithm. Finally, Laguerre diagrams are calculated from the obtained sphere packings. The centers of the spheres give the centers of the Laguerre cells, and their radii determine the cells' weights. The cell sizes in the obtained Laguerre diagrams have a distribution similar to that of the grains obtained from the image segmentation. That is why those diagrams are a convenient model of the original crystalline structure. The above-outlined procedure has been used to model real polycrystalline metallic materials. The main difference with previously existing methods lies in the use of a better particle packing algorithm.

  16. Hyperkalemia after irradiation of packed red blood cells: Possible effects with intravascular fetal transfusion

    International Nuclear Information System (INIS)

    Thorp, J.A.; Plapp, F.V.; Cohen, G.R.; Yeast, J.D.; O'Kell, R.T.; Stephenson, S.

    1990-01-01

    Plasma potassium, calcium, and albumin concentrations in irradiated blood, and in fetal blood before and after transfusion, were measured. Dangerously high plasma potassium levels were observed in some units of irradiated packed red blood cells (range, 13.9 to 66.5 mEq/L; mean, 44.7 mEq/L) and could be one possible explanation for the high incidence of fetal arrhythmia associated with fetal intravascular transfusion. There are many factors operative in the preparation of irradiated packed red blood cells that may predispose to high potassium levels: the age of the red blood cells, the number of procedures used to concentrate the blood, the duration of time elapsed from concentration, the duration of time elapsed from irradiation, and the hematocrit. Use of fresh blood, avoidance of multiple packing procedures, limiting the hematocrit in the donor unit to less than or equal to 80%, and minimizing the time between concentration, irradiation and transfusion may minimize the potassium levels, and therefore making an additional washing procedure unnecessary

  17. [Evaluation of non-compliance of transfusion requests of packed red blood cells].

    Science.gov (United States)

    Ben Romdhane, Asma Rym; Ben Ayoub, Wided; Gouider, Emna

    2015-06-01

    Despite legislative acts develloped, many deficiencies were identified in blood requests at the National Blood TransfusionCenter impedding board and blood safety. to evaluate the conformity of the different topics of packed red blood cells requests to the legislation. Our study was prospective descriptive lasting six months (March-August 2011). It assessed all packed red blood cells requests which reached the national blood transfusion center. 16064 packed red blood cells requests from 21 public institutions and 28 private institutions were studied. There was different deficiencies in each item.The absence of birth date in 67.18% of request represented the largest non-compliance within administrative information. A predominance of shortcomings related to transfusion and obstetric history was recorded for clinical information with absence of date of the last transfusion in 91.72% cases, lack of accuracy of any previous transfusion reactions in 88.63% cases and absence of the number of previous pregnancies in 93.15% of transfusion requests prescribed to women. Non-conformities related to the prescribing physician concerned mainly the phone number which was absent in 55.82% of cases. This study revealed a significant lack of awareness of physicians in relation to the law governing transfusion. It is therefore essential to develop training for prescribers to improve transfusion safety.

  18. Test of hybrid power system for electrical vehicles using a lithium-ion battery pack and a reformed methanol fuel cell range extender

    DEFF Research Database (Denmark)

    Andreasen, Søren Juhl; Ashworth, Leanne; Sahlin, Simon Lennart

    2014-01-01

    This work presents the proof-of-concept of an electric traction power system with a high temperature polymer electrolyte membrane fuel cell range extender, usable for automotive class electrical vehicles. The hybrid system concept examined, consists of a power system where the primary power...... is delivered by a lithium ion battery pack. In order to increase the run time of the application connected to this battery pack, a high temperature PEM (HTPEM) fuel cell stack acts as an on-board charger able to charge a vehicle during operation as a series hybrid. Because of the high tolerance to carbon...... monoxide, the HTPEM fuel cell system can efficiently use a liquid methanol/water mixture of 60%/40% by volume, as fuel instead of compressed hydrogen, enabling potentially a higher volumetric energy density. In order to test the performance of such a system, the experimental validation conducted uses...

  19. Approaching an experimental electron density model of the biologically active trans -epoxysuccinyl amide group-Substituent effects vs. crystal packing

    Energy Technology Data Exchange (ETDEWEB)

    Shi, Ming W.; Stewart, Scott G.; Sobolev, Alexandre N.; Dittrich, Birger; Schirmeister, Tanja; Luger, Peter; Hesse, Malte; Chen, Yu-Sheng; Spackman, Peter R.; Spackman, Mark A.; Grabowsky, Simon (Heinrich-Heine); (Freie); (UC); (Bremen); (JG-UM); (UWA)

    2017-01-24

    The trans-epoxysuccinyl amide group as a biologically active moiety in cysteine protease inhibitors such as loxistatin acid E64c has been used as a benchmark system for theoretical studies of environmental effects on the electron density of small active ingredients in relation to their biological activity. Here, the synthesis and the electronic properties of the smallest possible active site model compound are reported to close the gap between the unknown experimental electron density of trans-epoxysuccinyl amides and the well-known function of related drugs. Intramolecular substituent effects are separated from intermolecular crystal packing effects on the electron density, which allows us to predict the conditions under which an experimental electron density investigation on trans-epoxysuccinyl amides will be possible. In this context, the special importance of the carboxylic acid function in the model compound for both crystal packing and biological activity is revealed through the novel tool of model energy analysis.

  20. Modelling Thermal Effects of Battery Cells inside Electric Vehicle Battery Packs

    DEFF Research Database (Denmark)

    Khan, Mohammad Rezwan; Kær, Søren Knudsen

    The poster presents a methodology to account for thermal effects on battery cells to improve the typical thermal performances in a pack through heating calculations generally performed under the operating condition assumption. The aim is to analyze the issues based on battery thermo......-physical characteristics and their impact on the electrical state of battery cells(Khan, Mulder et al. 2013, Khan, Andreasen et al. 2014, Khan et al. 2014, Khan, Mulder et al. 2014, Khan, Nielsen et al. 2014). Based on this analysis, we derive strategies in achieving the goal, and then propose a battery thermal management...

  1. A study on parameter variation effects on battery packs for electric vehicles

    Science.gov (United States)

    Zhou, Long; Zheng, Yuejiu; Ouyang, Minggao; Lu, Languang

    2017-10-01

    As one single cell cannot meet power and driving range requirement in an electric vehicle, the battery packs with hundreds of single cells connected in parallel and series should be constructed. The most significant difference between a single cell and a battery pack is cell variation. Not only does cell variation affect pack energy density and power density, but also it causes early degradation of battery and potential safety issues. The cell variation effects on battery packs are studied, which are of great significant to battery pack screening and management scheme. In this study, the description for the consistency characteristics of battery packs was first proposed and a pack model with 96 cells connected in series was established. A set of parameters are introduced to study the cell variation and their impacts on battery packs are analyzed through the battery pack capacity loss simulation and experiments. Meanwhile, the capacity loss composition of the battery pack is obtained and verified by the temperature variation experiment. The results from this research can demonstrate that the temperature, self-discharge rate and coulombic efficiency are the major affecting parameters of cell variation and indicate the dissipative cell equalization is sufficient for the battery pack.

  2. A New Family of Multilevel Grid Connected Inverters Based on Packed U Cell Topology.

    Science.gov (United States)

    Pakdel, Majid; Jalilzadeh, Saeid

    2017-09-29

    In this paper a novel packed U cell (PUC) based multilevel grid connected inverter is proposed. Unlike the U cell arrangement which consists of two power switches and one capacitor, in the proposed converter topology a lower DC power supply from renewable energy resources such as photovoltaic arrays (PV) is used as a base power source. The proposed topology offers higher efficiency and lower cost using a small number of power switches and a lower DC power source which is supplied from renewable energy resources. Other capacitor voltages are extracted from the base lower DC power source using isolated DC-DC power converters. The operation principle of proposed transformerless multilevel grid connected inverter is analyzed theoretically. Operation of the proposed multilevel grid connected inverter is verified through simulation studies. An experimental prototype using STM32F407 discovery controller board is performed to verify the simulation results.

  3. Heterogeneity, Cell Biology and Tissue Mechanics of Pseudostratified Epithelia: Coordination of Cell Divisions and Growth in Tightly Packed Tissues.

    Science.gov (United States)

    Strzyz, P J; Matejcic, M; Norden, C

    2016-01-01

    Pseudostratified epithelia (PSE) are tightly packed proliferative tissues that are important precursors of the development of diverse organs in a plethora of species, invertebrate and vertebrate. PSE consist of elongated epithelial cells that are attached to the apical and basal side of the tissue. The nuclei of these cells undergo interkinetic nuclear migration (IKNM) which leads to all mitotic events taking place at the apical surface of the epithelium. In this review, we discuss the intricacies of proliferation in PSE, considering cell biological, as well as the physical aspects. First, we summarize the principles governing the invariability of apical nuclear migration and apical cell division as well as the importance of apical mitoses for tissue proliferation. Then, we focus on the mechanical and structural features of these tissues. Here, we discuss how the overall architecture of pseudostratified tissues changes with increased cell packing. Lastly, we consider possible mechanical cues resulting from these changes and their potential influence on cell proliferation. Copyright © 2016 Elsevier Inc. All rights reserved.

  4. Assessment of Microbial Fuel Cell Configurations and Power Densities

    KAUST Repository

    Logan, Bruce E.

    2015-07-30

    Different microbial electrochemical technologies are being developed for a many diverse applications, including wastewater treatment, biofuel production, water desalination, remote power sources, and as biosensors. Current and energy densities will always be limited relative to batteries and chemical fuel cells, but these technologies have other advantages based on the self-sustaining nature of the microorganisms that can donate or accept electrons from an electrode, the range of fuels that can be used, and versatility in the chemicals that can be produced. The high cost of membranes will likely limit applications of microbial electrochemical technologies that might require a membrane. For microbial fuel cells, which do not need a membrane, questions remain on whether larger-scale systems can produce power densities similar to those obtained in laboratory-scale systems. It is shown here that configuration and fuel (pure chemicals in laboratory media versus actual wastewaters) remain the key factors in power production, rather than the scale of the application. Systems must be scaled up through careful consideration of electrode spacing and packing per unit volume of reactor.

  5. Microbial desalination cells packed with ion-exchange resin to enhance water desalination rate.

    Science.gov (United States)

    Morel, Alexandre; Zuo, Kuichang; Xia, Xue; Wei, Jincheng; Luo, Xi; Liang, Peng; Huang, Xia

    2012-08-01

    A novel configuration of microbial desalination cell (MDC) packed with ion-exchange resin (R-MDC) was proposed to enhance water desalination rate. Compared with classic MDC (C-MDC), an obvious increase in desalination rate (DR) was obtained by R-MDC. With relatively low concentration (10-2 g/L NaCl) influents, the DR values of R-MDC were about 1.5-8 times those of C-MDC. Ion-exchange resins packed in the desalination chamber worked as conductor and thus counteracted the increase in ohmic resistance during treatment of low concentration salt water. Ohmic resistances of R-MDC stabilized at 3.0-4.7 Ω. By contrast, the ohmic resistances of C-MDC ranged from 5.5 to 12.7 Ω, which were 55-272% higher than those of R-MDC. Remarkable improvement in desalination rate helped improve charge efficiency for desalination in R-MDC. The results first showed the potential of R-MDC in the desalination of water with low salinity. Copyright © 2012 Elsevier Ltd. All rights reserved.

  6. High power density solid oxide fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Pham, Ai Quoc; Glass, Robert S.

    2004-10-12

    A method for producing ultra-high power density solid oxide fuel cells (SOFCs). The method involves the formation of a multilayer structure cells wherein a buffer layer of doped-ceria is deposited intermediate a zirconia electrolyte and a cobalt iron based electrode using a colloidal spray deposition (CSD) technique. For example, a cobalt iron based cathode composed of (La,Sr)(Co,Fe)O (LSCF) may be deposited on a zirconia electrolyte via a buffer layer of doped-ceria deposited by the CSD technique. The thus formed SOFC have a power density of 1400 mW/cm.sup.2 at 600.degree. C. and 900 mW/cm.sup.2 at 700.degree. C. which constitutes a 2-3 times increased in power density over conventionally produced SOFCs.

  7. Relationship between haemoglobin concentration and packed cell volume in cattle blood samples

    Directory of Open Access Journals (Sweden)

    Paa-Kobina Turkson

    2015-02-01

    Full Text Available A convention that has been adopted in medicine is to estimate haemoglobin (HB concentration as a third of packed cell volume (PCV or vice versa. The present research set out to determine whether a proportional relationship exists between PCV and Hb concentration in cattle blood samples, and to assess the validity of the convention of estimating Hb concentration as a third of PCV. A total of 440 cattle in Ghana from four breeds (Ndama, 110; West African Short Horn, 110; Zebu, 110 and Sanga, 110 were bled for haematological analysis, specifically packed cell volume, using the microhaematocrit technique and haemoglobin concentration using the cyanmethaemoglobin method. Means, standard deviations, standard errors of mean and 95% confidence intervals were calculated. Trendline analyses generated linear regression equations from scatterplots. For all the cattle, a significant and consistent relationship (r = 0.74 was found between Hb concentration and PCV (%. This was expressed as Hb concentration (g/dL = 0.28 PCV + 3.11. When the Hb concentration was estimated by calculating it as a third of PCV, the relationship was expressed in linear regression as Hb concentration (g/dL = 0.83 calculated Hb + 3.11. The difference in the means of determined (12.2 g/dL and calculated (10.9 g/dL Hb concentrations for all cattle was significant (p < 0.001, whereas the difference in the means of determined Hb and corrected calculated Hb was not significant. In conclusion, a simplified relationship of Hb (g/dL = (0.3 PCV + 3 may provide a better estimate of Hb concentration from the PCV of cattle.

  8. Preparation and structure of a low-density, flat-lying decanethiol monolayer from the densely packed, upright monolayer on gold.

    Science.gov (United States)

    Picraux, Laura B; Zangmeister, Christopher D; Batteas, James D

    2006-01-03

    This study investigates the formation of low-density, flat-lying decanethiol chemisorbed on Au prepared by heating the surface covered with a densely packed, upright monolayer to a surface temperature above that of the onset of desorption. We determined conditions for preparing the low-density phase by observing the evolution of the photoemission spectrum as a function of the surface temperature using polarized ultraviolet light and by utilizing scanning tunneling microscopy. The preparation conditions were similar for single- and polycrystalline gold surfaces. Once the low-density decanethiol phase was formed, reflection absorption infrared spectroscopy was employed to determine the orientation of the carbon chain backbone with respect to the Au surface. The nature of the valance electronic structure for flat-lying decanethiol is described.

  9. Evaluation of Hematological Parameters in Partial Exchange and Packed Cell Transfusion in Treatment of Severe Anemia in Pregnancy

    Directory of Open Access Journals (Sweden)

    Sudha Salhan

    2012-01-01

    Full Text Available Objectives. Anemia is a major public health problem throughout the world which assumes prominence in pregnant mothers. Patients with severe anemia continue to present themselves at term or in labor. This study was conducted to compare the improvements in hematological parameters of patients receiving partial exchange blood transfusion and transfusion of packed cells without exchange. Methods. One hundred and twenty-five severely anemic antenatal mothers were admitted from outpatient service. Partial exchange transfusion was given to sixty-six patients while fifty-nine received transfusion of packed cells with frusemide cover. Results. The two groups were comparable in terms of age, height, weight, religion, diet, education, occupation of self and husband, and income. Hemoglobin level in Group 1 was comparatively less than Group 2 at prelevel (5.2±1.5 versus 6.6±2.3, P=0.001 and postlevel (7.2±1.5 versus 8.6±1.8, P=0.001, respectively, but there was no significant difference between the two modes of transfusion (2.09±1.6 versus 2.01±1.5, P=0.78. Conclusion. The study produced an equally significant improvement in hematological parameters in partial exchange and packed cell transfusion. Platelet counts were significantly less in partial exchange as compared with packed cell transfusion.

  10. Effect of Molecular Packing and Charge Delocalization on the Nonradiative Recombination of Charge-Transfer States in Organic Solar Cells

    KAUST Repository

    Chen, Xiankai

    2016-09-05

    In organic solar cells, a major source of energy loss is attributed to nonradiative recombination from the interfacial charge transfer states to the ground state. By taking pentacene–C60 complexes as model donor–acceptor systems, a comprehensive theoretical understanding of how molecular packing and charge delocalization impact these nonradiative recombination rates at donor–acceptor interfaces is provided.

  11. Impact of the Nature of the Side-Chains on the Polymer-Fullerene Packing in the Mixed Regions of Bulk Heterojunction Solar Cells

    KAUST Repository

    Wang, Tonghui

    2016-06-20

    Polymer-fullerene packing in mixed regions of a bulk heterojunction solar cell is expected to play a major role in exciton-dissociation, charge-separation, and charge-recombination processes. Here, molecular dynamics simulations are combined with density functional theory calculations to examine the impact of nature and location of polymer side-chains on the polymer-fullerene packing in mixed regions. The focus is on poly-benzo[1,2-b:4,5-b′]dithiophene-thieno[3,4-c]pyrrole-4,6-dione (PBDTTPD) as electron-donating material and [6,6]-phenyl-C61-butyric acid methyl ester (PC61BM) as electron-accepting material. Three polymer side-chain patterns are considered: i) linear side-chains on both benzodithiophene (BDT) and thienopyrroledione (TPD) moieties; ii) two linear side-chains on BDT and a branched side-chain on TPD; and iii) two branched side-chains on BDT and a linear side-chain on TPD. Increasing the number of branched side-chains is found to decrease the polymer packing density and thereby to enhance PBDTTPD–PC61 BM mixing. The nature and location of side-chains are found to play a determining role in the probability of finding PC61BM molecules close to either BDT or TPD. The electronic couplings relevant for the exciton-dissociation and charge-recombination processes are also evaluated. Overall, the findings are consistent with the experimental evolution of the PBDTTPD–PC61BM solar-cell performance as a function of side-chain patterns. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

  12. Time Dependent Assessment of Morphological Changes: Leukodepleted Packed Red Blood Cells Stored in SAGM

    Directory of Open Access Journals (Sweden)

    Ibrahim Mustafa

    2016-01-01

    Full Text Available Usually packed red blood cells (pRBCs require specific conditions in storage procedures to ensure the maximum shelf life of up to 42 days in 2–6°C. However, molecular and biochemical consequences can affect the stored blood cells; these changes are collectively labeled as storage lesions. In this study, the effect of prolonged storage was assessed through investigating morphological changes and evaluating oxidative stress. Samples from leukodepleted pRBC in SAGM stored at 4°C for 42 days were withdrawn aseptically on day 0, day 14, day 28, and day 42. Morphological changes were observed using scanning electron microscopy and correlated with osmotic fragility and hematocrit. Oxidative injury was studied through assessing MDA level as a marker for lipid peroxidation. Osmotic fragility test showed that extended storage time caused increase in the osmotic fragility. The hematocrit increased by 6.6% from day 0 to day 42. The last 2 weeks show alteration in the morphology with the appearance of echinocytes and spherocytes. Storage lesions and morphological alterations appeared to affect RBCs during the storage period. Further studies should be performed to develop strategies that will aid in the improvement of stored pRBC quality and efficacy.

  13. Cell Free Xanthan Gum Production Using Continuous Recycled Packed Fibrous-bed Bioreactor-membrane

    Directory of Open Access Journals (Sweden)

    Rosalam, S.

    2008-01-01

    Full Text Available Although the xanthan gum has been produced as a commercial commodity, the biomass isolation and its recovery are still challenging. This study revealed the xanthan gum production by fermentation of Xanthomonas campestris DSMZ using glucose as a carbon source in an immobilised batch and a continuous recycled packed fibrous-bed bioreactor-membrane (CRPBFBM. The pure cotton fibre was used to immobilise the microbial cell biomass and to isolate from the liquid phase containing medium and xanthan gum. The cellulose acetate membrane with 0.45 µm was used to recover the xanthan gum. The batch fermentation showed that the immobilisation technique gave higher xanthan gum concentration at 20g/L than the free moving cell without immobilisation at 18g/L. The CRPBBM produced the highest xanthan gum concentration at 18.7 g/L at the dilution rate of 1.44 d-1. The highest production rate of CRPBFBM was 0.475 g/L-h. Further research needs to be conducted to ascertain the stability of the Xanthomonas Campestris DSMZ during a long period of continuous fermentation as well as up scaling the CRPBFBM.

  14. Nanodefects of membranes cause destruction of packed red blood cells during long-term storage

    Energy Technology Data Exchange (ETDEWEB)

    Kozlova, Elena, E-mail: waterlake@mail.ru [V.A. Negovsky Scientific Research Institute of General Reanimatology, Moscow (Russian Federation); I.M. Sechenov First Moscow State Medical University, Moscow (Russian Federation); Chernysh, Aleksandr [V.A. Negovsky Scientific Research Institute of General Reanimatology, Moscow (Russian Federation); I.M. Sechenov First Moscow State Medical University, Moscow (Russian Federation); Moroz, Victor; Sergunova, Victoria; Gudkova, Olga; Kuzovlev, Artem [V.A. Negovsky Scientific Research Institute of General Reanimatology, Moscow (Russian Federation)

    2015-10-01

    Packed red blood cells (PRBC) are used for blood transfusion. PRBC were stored for 30 days under 4 °C in hermetic blood bags with CPD anticoagulant-preservative solution. Hematocrit was 50–55%. The distortions of PRBC membranes nanostructure and cells morphology during storage were studied by atomic force microscopy. Basic measurements were performed at the day 2, 6, 9, 16, 23 and 30 of storage and additionally 2–3 days after it. Topological defects occurred on RBC membranes by day 9. They appeared as domains with grain-like structures (“grains”) sized up to 200 nm. These domains were appeared in almost all cells. Later these domains merged and formed large defects on cells. It was the formation of domains with the “grains” which was onset process leading eventually to destruction of PRBC. Possible mechanisms of transformation of PRBC and their membrane are related to the alterations of spectrin cytoskeleton. During this storage period potassium ions and lactat concentrations increased, pH decreased, intracellular concentration of reduced glutathione diminished in the preservative solution. Changes of PRBC morphology were detected within the entire period of PRBC storage. Discocytes predominated at the days 1 and 2. By day 30 PRBC transformed into irreversible echinocytes and spheroechinocytes. Study of defects of membranes nanostructure may form the basis of assessing the quality of the stored PRBC. This method may allow to work out the best recommendations for blood transfusion. - Highlights: • Domains with “grains” are formed on membranes surface on 9–16 days of PRBC storage. • The development of domains is the reason of irreversible changes of PRBC structure. • The origin of domains is the consequence of alterations of spectrin cytoskeleton. • Study of nanostructure may form basis of assessing the quality of the stored PRBC.

  15. Nanodefects of membranes cause destruction of packed red blood cells during long-term storage

    International Nuclear Information System (INIS)

    Kozlova, Elena; Chernysh, Aleksandr; Moroz, Victor; Sergunova, Victoria; Gudkova, Olga; Kuzovlev, Artem

    2015-01-01

    Packed red blood cells (PRBC) are used for blood transfusion. PRBC were stored for 30 days under 4 °C in hermetic blood bags with CPD anticoagulant-preservative solution. Hematocrit was 50–55%. The distortions of PRBC membranes nanostructure and cells morphology during storage were studied by atomic force microscopy. Basic measurements were performed at the day 2, 6, 9, 16, 23 and 30 of storage and additionally 2–3 days after it. Topological defects occurred on RBC membranes by day 9. They appeared as domains with grain-like structures (“grains”) sized up to 200 nm. These domains were appeared in almost all cells. Later these domains merged and formed large defects on cells. It was the formation of domains with the “grains” which was onset process leading eventually to destruction of PRBC. Possible mechanisms of transformation of PRBC and their membrane are related to the alterations of spectrin cytoskeleton. During this storage period potassium ions and lactat concentrations increased, pH decreased, intracellular concentration of reduced glutathione diminished in the preservative solution. Changes of PRBC morphology were detected within the entire period of PRBC storage. Discocytes predominated at the days 1 and 2. By day 30 PRBC transformed into irreversible echinocytes and spheroechinocytes. Study of defects of membranes nanostructure may form the basis of assessing the quality of the stored PRBC. This method may allow to work out the best recommendations for blood transfusion. - Highlights: • Domains with “grains” are formed on membranes surface on 9–16 days of PRBC storage. • The development of domains is the reason of irreversible changes of PRBC structure. • The origin of domains is the consequence of alterations of spectrin cytoskeleton. • Study of nanostructure may form basis of assessing the quality of the stored PRBC

  16. Accuracy of formulas used to predict post-transfusion packed cell volume rise in anemic dogs.

    Science.gov (United States)

    Short, Jacqueline L; Diehl, Shenandoah; Seshadri, Ravi; Serrano, Sergi

    2012-08-01

    To assess the accuracy of published formulas used to guide packed red blood cell (pRBC) transfusions in anemic dogs and to compare the predicted rise in packed cell volume (PCV) to the actual post-transfusion rise in PCV. Prospective observational study from April 2009 through July 2009. A small animal emergency and specialty hospital. Thirty-one anemic client-owned dogs that received pRBC transfusions for treatment of anemia. None Four formulas were evaluated to determine their predictive ability with respect to rise in PCV following transfusion with pRBC. Post-transfusion rise in PCV were compared to calculated rise in PCV using 4 different formulas. Bias and limits of agreement were investigated using Bland-Altman analyses. Accuracy of existing formulas to predict rise in PCV following transfusion varied significantly. Formula 1 (volume to be transfused [VT] [mL] = 1 mL × % PCV rise × kg body weight [BW]) overestimated the expected rise in PCV (mean difference, 6.30), while formula 2 (VT [mL] = 2 mL ×% PCV rise × kg BW) underestimated the rise in PCV (mean difference, -3.01). Formula 3 (VT [mL] = 90 mL × kg BW × [(desired PCV - Patient PCV)/PCV of donor blood]) and formula 4 (VT [mL] = 1.5 mL ×% PCV rise × kg BW) performed well (mean difference 0.23 and 0.09, respectively) in predicting rise in PCV following pRBC transfusion. Agreement between 2 formulas, "VT (mL) = kg BW × blood volume (90 mL) × [(desired PCV - recipient PCV)/Donor PCV]" and "VT (mL) = 1.5 ×desired rise in PCV × kg BW," was found when they were compared to the actual rise in PCV following pRBC transfusion in anemic dogs. Further research is warranted to determine whether these formulas perform similarly well for other species. © Veterinary Emergency and Critical Care Society 2012.

  17. From Fullerene-Polymer to All-Polymer Solar Cells: The Importance of Molecular Packing, Orientation, and Morphology Control.

    Science.gov (United States)

    Kang, Hyunbum; Lee, Wonho; Oh, Jiho; Kim, Taesu; Lee, Changyeon; Kim, Bumjoon J

    2016-11-15

    All-polymer solar cells (all-PSCs), consisting of conjugated polymers as both electron donor (P D ) and acceptor (P A ), have recently attracted great attention. Remarkable progress has been achieved during the past few years, with power conversion efficiencies (PCEs) now approaching 8%. In this Account, we first discuss the major advantages of all-PSCs over fullerene-polymer solar cells (fullerene-PSCs): (i) high light absorption and chemical tunability of P A , which affords simultaneous enhancement of both the short-circuit current density (J SC ) and the open-circuit voltage (V OC ), and (ii) superior long-term stability (in particular, thermal and mechanical stability) of all-PSCs due to entangled long P A chains. In the second part of this Account, we discuss the device operation mechanism of all-PSCs and recognize the major challenges that need to be addressed in optimizing the performance of all-PSCs. The major difference between all-PSCs and fullerene-PSCs originates from the molecular structures and interactions, i.e., the electron transport ability in all-PSCs is significantly affected by the packing geometry of two-dimensional P A chains relative to the electrodes (e.g., face-on or edge-on orientation), whereas spherically shaped fullerene acceptors can facilitate isotropic electron transport properties in fullerene-PSCs. Moreover, the crystalline packing structures of P D and P A at the P D -P A interface greatly affect their free charge carrier generation efficiencies. The design of P A polymers (e.g., main backbone, side chain, and molecular weight) should therefore take account of optimizing three major aspects in all-PSCs: (1) the electron transport ability of P A , (2) the molecular packing structure and orientation of P A , and (3) the blend morphology. First, control of the backbone and side-chain structures, as well as the molecular weight, is critical for generating strong intermolecular assembly of P A and its network, thus enabling high

  18. [A pregnant woman with irregular erythrocyte antibodies for whom no compatible packed red blood cells were available].

    Science.gov (United States)

    Boonstra, J G; Overbeeke, M A M; de Rijke, Y B; Duvekot, J J

    2005-11-19

    A 45-year-old woman underwent a Caesarean section at a gestational age of over 32 weeks. Screening for irregular erythrocyte antibodies in the transfusion laboratory yielded a positive result. It appeared that the patient had for several years been known to have antibodies against At(a), a high-frequency antigen that may cause severe transfusion reactions when incompatible packed cells are administered. No autologous donated blood was available and the only compatible At(a)-negative unit of packed cells in the Blood Bank of the Council of Europe was damaged during the thawing process. A cell saver was therefore used during the Caesarean section, and family members were summoned for donation. This case report illustrates the necessity of a transfusion plan for pregnant women with (rare) irregular antibodies.

  19. Effect of monocular deprivation on rabbit neural retinal cell densities

    Directory of Open Access Journals (Sweden)

    Philip Maseghe Mwachaka

    2015-01-01

    Conclusion: In this rabbit model, monocular deprivation resulted in activity-dependent changes in cell densities of the neural retina in favour of the non-deprived eye along with reduced cell densities in the deprived eye.

  20. Packed red blood cells are an abundant and proximate potential source of nitric oxide synthase inhibition.

    Directory of Open Access Journals (Sweden)

    Charles F Zwemer

    Full Text Available We determined, for packed red blood cells (PRBC and fresh frozen plasma, the maximum content, and ability to release the endogenous nitric oxide synthase (NOS inhibitors asymmetric dimethylarginine (ADMA and monomethylarginine (LNMMA.ADMA and LNMMA are near equipotent NOS inhibitors forming blood's total NOS inhibitory content. The balance between removal from, and addition to plasma determines their free concentrations. Removal from plasma is by well-characterized specific hydrolases while formation is restricted to posttranslational protein methylation. When released into plasma they can readily enter endothelial cells and inhibit NOS. Fresh rat and human whole blood contain substantial protein incorporated ADMA however; the maximum content of ADMA and LNMMA in PRBC and fresh frozen plasma has not been determined.We measured total (free and protein incorporated ADMA and LNMMA content in PRBCs and fresh frozen plasma, as well as their incubation induced release, using HPLC with fluorescence detection. We tested the hypothesis that PRBC and fresh frozen plasma contain substantial inhibitory methylarginines that can be released chemically by complete in vitro acid hydrolysis or physiologically at 37°C by enzymatic blood proteolysis.In vitro strong-acid-hydrolysis revealed a large PRBC reservoir of ADMA (54.5 ± 9.7 µM and LNMMA (58.9 ± 28.9 μM that persisted over 42-d at 6° or -80°C. In vitro 5h incubation at 37°C nearly doubled free ADMA and LNMMNA concentration from PRBCs while no change was detected in fresh frozen plasma.The compelling physiological ramifications are that regardless of storage age, 1 PRBCs can rapidly release pathologically relevant quantities of ADMA and LNMMA when incubated and 2 PRBCs have a protein-incorporated inhibitory methylarginines reservoir 100 times that of normal free inhibitory methylarginines in blood and thus could represent a clinically relevant and proximate risk for iatrogenic NOS inhibition upon

  1. [Effectiveness of a nursing intervention on patient anxiety before transfusion of packed red blood cells].

    Science.gov (United States)

    Martín Díaz, Jesús Fernando; Hidalgo Gutiérrez, M Jesús; Cerezo Solana, M Fátima; Martín Morcillo, Jaime

    2013-01-01

    To evaluate the effectiveness of an educational intervention regarding anxiety and satisfaction in patients requiring a red blood cell transfusion. Randomised, controlled, single-blind clinical trial in patients requiring a packed red blood cell transfusion. alpha=.05, beta=.10, to detect a 10% difference, 70 subjects in each group. The sampling recruitment was randomised to the intervention group (IG) and the control group (CG). an intervention protocol with oral and written information using a published guide on the safety, risks and benefits of haemotherapy for the IG, and an equivalent one on general health topics for the CG. pre- and post-anxiety state; Spielberger's validated questionnaire: STAI. Satisfaction, by an ad hoc questionnaire. Sociodemographic and clinical variables: description, reason for transfusion, prescription knowledge, incidents, records. There was a total of 144 subjects, 73 (50.69%) in the IG, and 71 (49.31%) in the CG. The mean age was 55.80 years, with 56.94% males, and a first transfusion in 52.08%. Comparability between the IG and the CG was tested and confirmed. The decrease in anxiety after the intervention for the IG was 19.99, compared to 25.48 in CG. The difference was greater than the proposed 10%, and was statistically significant. The preference for information was 98.60% in IG, compared to 43.70% in CG. The hypothesis was confirmed; a protocolised nursing educational intervention protocol increased patient satisfaction with nursing care, and decreased patient anxiety, thus preventing complications and providing greater safety to the users. Copyright © 2013 Elsevier España, S.L. All rights reserved.

  2. Enhanced desalination performance of membrane capacitive deionization cells by packing the flow chamber with granular activated carbon.

    Science.gov (United States)

    Bian, Yanhong; Yang, Xufei; Liang, Peng; Jiang, Yong; Zhang, Changyong; Huang, Xia

    2015-11-15

    A new design of membrane capacitive deionization (MCDI) cell was constructed by packing the cell's flow chamber with granular activated carbon (GAC). The GAC packed-MCDI (GAC-MCDI) delivered higher (1.2-2.5 times) desalination rates than the regular MCDI at all test NaCl concentrations (∼ 100-1000 mg/L). The greatest performance enhancement by packed GAC was observed when treating saline water with an initial NaCl concentration of 100 mg/L. Several different GAC materials were tested and they all exhibited similar enhancement effects. Comparatively, packing the MCDI's flow chamber with glass beads (GB; non-conductive) and graphite granules (GG; conductive but with lower specific surface area than GAC) resulted in inferior desalination performance. Electrochemical impedance spectroscopy (EIS) analysis showed that the GAC-MCDI had considerably smaller internal resistance than the regular MCDI (∼ 19.2 ± 1.2 Ω versus ∼ 1222 ± 15 Ω at 100 mg/L NaCl). The packed GAC also decreased the ionic resistance across the flow chamber (∼ 1.49 ± 0.05 Ω versus ∼ 1130 ± 12 Ω at 100 mg/L NaCl). The electric double layer (EDL) formed on the GAC surface was considered to store salt ions during electrosorption, and facilitate the ion transport in the flow chamber because of the higher ion conductivity in the EDLs than in the bulk solution, thereby enhancing the MCDI's desalination rate. Copyright © 2015 Elsevier Ltd. All rights reserved.

  3. Power density investigations for the large wind turbines' grid-side press-pack IGBT 3L-NPC-VSCs

    DEFF Research Database (Denmark)

    Senturk, Osman Selcuk; Helle, Lars; Munk-Nielsen, Stig

    2012-01-01

    Power density is the important design criterion in wind turbine converter design provided that satisfactory converter performance is guaranteed. In order to assess a converter in terms of power density, which is dependent on converter electrical and thermal behaviors, converter electro......-point-piloted VSC (3L-NPP-VSC) are characterized in terms of converter operating principles, physical structure, power loss, and DC bus capacitor size for establishing the basis for converter electro-thermal modeling. Via the practical implementations of the converter electro-thermal models in a computation...... platform (e.g. MATLAB), these VSCs are investigated with respect to power capability and DC bus capacitor size. Based on these investigations, the VSCs' power densities are quantified and compared. It is shown that the converter power density can be improved by 13% for 3L-ANPC-VSC and by 22% for 3L...

  4. Density of pack-ice seals and penguins in the western Weddell Sea in relation to ice thickness and ocean depth

    Science.gov (United States)

    Flores, Hauke; Haas, Christian; van Franeker, Jan Andries; Meesters, Erik

    2008-04-01

    Aerial band transect censuses were carried out parallel with ice thickness profiling surveys in the pack ice of the western Weddell Sea during the ISPOL (Ice Station POLarstern) expedition of R.V. Polarstern from November 2004 to January 2005. Three regions were surveyed: the deep sea of the Weddell Sea, a western continental shelf/slope region where R.V. Polarstern passively drifted with an ice floe (ISPOL), and a northern region (N). Animal densities were compared among regions and in relation to bathymetry and ice thickness distribution. Crabeater seals Lobodon carcinophaga were the most abundant species in all three regions. Their density was significantly lower in the deep sea (0.50 km -2) than in the ISPOL (1.00 km -2) and northern regions (1.21 km -2). Weddell seals Leptonychotes weddellii were not sighted in the deep-sea region, their density elsewhere ranging from 0.03 (N) to 0.08 km -2 (ISPOL). Leopard seals Hydrurga leptonyx were observed in all three areas, but could only be quantified in the deep-sea (0.05 km -2) and northern regions (0.06 km -2). The abundance of emperor penguins Aptenodytes forsteri was markedly higher in the northern (0.75 km -2) than in the ISPOL (0.13 km -2) and the deep-sea region (not quantified). Crabeater seal density was significantly related to ocean depth and modal ice thickness.

  5. A LiFePO4 battery pack capacity estimation approach considering in-parallel cell safety in electric vehicles

    International Nuclear Information System (INIS)

    Wang, Limei; Cheng, Yong; Zhao, Xiuliang

    2015-01-01

    Highlights: • Find the influence of in-parallel battery cell variations on battery pack capacity. • Redefine the battery module capacity with considering ANY battery cell safety. • Discuss the safety end-of-charge voltage for an aged in-parallel battery module. • Build an algorithm for battery pack capacity estimation with the charge curve. • Bench tests are used to verify the validity of the proposed algorithm. - Abstract: In electric vehicles (EVs), several battery cells are connected in parallel to establish a battery module. The safety of the battery module is influenced by inconsistent battery cell performance which causes uneven currents flowing through internal in-parallel battery cells. A battery cell model is developed based on the Matlab–Simscape platform and validated by tests. The battery cell model is used to construct simulation models for analyzing the effect of battery cell inconsistency on the performance of an in-parallel battery module. Simulation results indicate that the state-of-charge (SOC) of a battery module cannot characterize the SOC of ALL the internal battery cells in the battery module. When the battery management system (BMS) controls the end-of-charge (EOC) time according to the SOC of a battery module, some internal battery cells are over-charged. To guarantee the safety of ALL battery cells through the whole battery life, a safety EOC voltage of the battery module should be set according to the number of battery cells in the battery module and the applied charge current. Simulations reveal that the SOC of the “normal battery module” is related to its charge voltage when aged battery module is charged to the EOC voltage. Then, a function describing their relationship is established. Both the capacity and the charge voltage shift are estimated by comparing the measured voltage-to-capacity curve with the standard one provided by the manufactory. A battery pack capacity estimation method is proposed according to the SOC

  6. Early coagulopathy and metabolic acidosis predict transfusion of packed red blood cells in pediatric trauma patients.

    Science.gov (United States)

    Smith, Shane A; Livingston, Michael H; Merritt, Neil H

    2016-05-01

    Severely injured pediatric trauma patients often present to hospital with early coagulopathy and metabolic acidosis. These derangements are associated with poor outcomes, but it is unclear to what degree they predict transfusion of packed red blood cells (pRBC). We retrospectively identified pediatric trauma patients from a level 1 trauma center from 2006 to 2013. Inclusion criteria were age less than 18years, Injury Severity Score greater than 12, and pRBC transfusion within 24h of admission. We identified 96 pediatric trauma patients who underwent pRBC transfusion within 24h of presentation to hospital. On admission, 43% of these patients had one or more signs of coagulopathy, and 81% had metabolic acidosis. Size of pRBC transfusion in the first 24h ranged from 3 to 177mL/kg (mean 29mL/kg), and nineteen patients (20%) underwent massive transfusion (>40ml/kg in 24h). Univariate analysis indicated that size of pRBC transfusion was associated with initial base excess (r=0.46), international normalized ratio (r=0.35), partial thromboplastin time (r=0.41), fibrinogen (r=0.46), and BIG score (Base deficit, INR, Glasgow Coma Scale (GCS), r=0.36). Platelet count, age, GCS, and direct versus referred presentation were not predictive. Multivariable linear regression confirmed that coagulopathy and metabolic acidosis remained predictive after adjusting for direct versus referred presentation (R(2)=0.30). Early coagulopathy and metabolic acidosis predict size of pRBC transfusion among pediatric trauma patients. Further research is needed to develop massive transfusion protocols and guidelines for activation. Copyright © 2016 Elsevier Inc. All rights reserved.

  7. Preliminary evaluation of rechargeable lithium-ion cells for an implantable battery pack

    Energy Technology Data Exchange (ETDEWEB)

    MacLean, G.K. [Cardiovascular Devices Div., Univ. Ottawa, Heart Inst., ON (Canada); Aiken, P.A. [Cardiovascular Devices Div., Univ. Ottawa, Heart Inst., ON (Canada); Adams, W.A. [Electrochemical Science and Technology Centre, Univ. Ottawa, ON (Canada); Mussivand, T. [Cardiovascular Devices Div., Univ. Ottawa, Heart Inst., ON (Canada)

    1995-07-01

    A preliminary evaluation of the performance characteristics of 1.08 Ah lithium-ion cells was undertaken utilizing operating conditions similar to that required for an implanted medical device, such as a ventricular assist device or total artificial heart, in order to determine their potential usefulness for this application. The major parameters studied at 22 or 37 C were discharge-rate capability, specific energy and energy density, surface temperature, self-discharge and cycle life. The discharge loads used in the cycle-life study were either constant or pulsatile, with the constant discharge load being equivalent to the average of the pulsatile load. The lithium-ion cells showed high discharge-rate capability up to 1.5 A at 37 C, with over 74% of their rated capacity being obtained and a midpoint voltage of over 3.3 V (>72% of rated capacity and >3.3 V for up to 1.0 A discharges at 22 C), before the first indication of cell polarization was noticed. The specific energy and energy density of cells discharged at 0.88 A to 2.5 V at 37 C was 73 Wh/kg and 190 Wh/l, respectively (64 Wh/kg and 167 Wh/l at 22 C). The internal resistance of the cells was calculated to be 198 m{Omega} at 37 C (316 m{Omega} at 22 C), which resulted in a relatively high, 8.0 C, increase in surface temperature under a 0.88 A discharge load. The self-discharge of the cells at 37 C was relatively low, with only a 1.3% loss in capacity being observed after 24 h. The lithium-ion cells yielded longer cycle lives at 37 C (2 239 cycles) compared with 22 C operation (1 539 cycles) under similar 0.88 A discharge loads. The cells peformed slightly better under constant discharge loads than under pulsatile loads of equivalent average current (0.83 A average) with cycles lives of 2 279 cycles versus 1941 cycles and operating times were 1.6{+-}1.1 min (mean) longer. (orig./MM)

  8. Decontamination of pesticide packing using ionizing radiation

    Science.gov (United States)

    Duarte, C. L.; Mori, M. N.; Kodama, Yasko; Oikawa, H.; Sampa, M. H. O.

    2007-11-01

    The Brazilian agriculture activities have consumed about 288,000 tons of pesticides per year conditioned in about 107,000,000 packing with weight of approximately 23,000 tons. The discharge of empty plastic packing of pesticides can be an environmental concern causing problems to human health, animals, and plants if done without inspection and monitoring. The objective of this work is to study the ionizing radiation effect in the main pesticides used in Brazil for plastic packing decontamination. Among the commercial pesticides, chlorpyrifos has significant importance because of its wide distribution and extensive use and persistence. The radiation-induced degradation of chlorpyrifos in liquid samples and in polyethylene pack was studied by gamma radiolysis. Packing of high-density polyethylene (HDPE) three layer coextruded, named COEX, contaminated with chlorpyrifos, were irradiated using both a multipurpose Co-60 gamma irradiator and a gamma source with 5000 Ci total activity Gamma cell type. The chemical analysis of the chlorpyrifos was made using a gas chromatography associated to the Mass Spectrometry—GCMS from Shimadzu Model QP 5000. Gamma radiation was efficient for removing chlorpyrifos from the plastic packing, in all studied cases.

  9. Decontamination of pesticide packing using ionizing radiation

    Energy Technology Data Exchange (ETDEWEB)

    Duarte, C.L. [Instituto de Pesquisas Energeticas e Nucleares-IPEN-CNEN/SP Av. Lineu Prestes 2.242, 05508-900, Sao Paulo, SP (Brazil)], E-mail: clduarte@ipen.br; Mori, M.N.; Kodama, Yasko; Oikawa, H.; Sampa, M.H.O. [Instituto de Pesquisas Energeticas e Nucleares-IPEN-CNEN/SP Av. Lineu Prestes 2.242, 05508-900, Sao Paulo, SP (Brazil)

    2007-11-15

    The Brazilian agriculture activities have consumed about 288,000 tons of pesticides per year conditioned in about 107,000,000 packing with weight of approximately 23,000 tons. The discharge of empty plastic packing of pesticides can be an environmental concern causing problems to human health, animals, and plants if done without inspection and monitoring. The objective of this work is to study the ionizing radiation effect in the main pesticides used in Brazil for plastic packing decontamination. Among the commercial pesticides, chlorpyrifos has significant importance because of its wide distribution and extensive use and persistence. The radiation-induced degradation of chlorpyrifos in liquid samples and in polyethylene pack was studied by gamma radiolysis. Packing of high-density polyethylene (HDPE) three layer coextruded, named COEX, contaminated with chlorpyrifos, were irradiated using both a multipurpose Co-60 gamma irradiator and a gamma source with 5000 Ci total activity Gamma cell type. The chemical analysis of the chlorpyrifos was made using a gas chromatography associated to the Mass Spectrometry-GCMS from Shimadzu Model QP 5000. Gamma radiation was efficient for removing chlorpyrifos from the plastic packing, in all studied cases.

  10. Battery Pack Thermal Design

    Energy Technology Data Exchange (ETDEWEB)

    Pesaran, Ahmad

    2016-06-14

    This presentation describes the thermal design of battery packs at the National Renewable Energy Laboratory. A battery thermal management system essential for xEVs for both normal operation during daily driving (achieving life and performance) and off-normal operation during abuse conditions (achieving safety). The battery thermal management system needs to be optimized with the right tools for the lowest cost. Experimental tools such as NREL's isothermal battery calorimeter, thermal imaging, and heat transfer setups are needed. Thermal models and computer-aided engineering tools are useful for robust designs. During abuse conditions, designs should prevent cell-to-cell propagation in a module/pack (i.e., keep the fire small and manageable). NREL's battery ISC device can be used for evaluating the robustness of a module/pack to cell-to-cell propagation.

  11. Particle passage kinetics and neutral detergent fiber degradability of silage of pineapple waste (aerial parts under different packing densities

    Directory of Open Access Journals (Sweden)

    Graciele Araújo de Oliveira Caetano

    2014-01-01

    Full Text Available The objective of this study was to determine the kinetics of in situ degradability parameters of the dry matter (DM and neutral detergent fiber (NDF and the passage of materials originating from the ensilage of the waste from pineapple cultivation (aerial parts. The four treatments utilized were silage of pineapple waste compacted at 600, 700, 900 and 1000 kg/m³. After ensiling the material from the pineapple cultivation, the particle-transit and rumen-degradation kinetics were analyzed. For the analysis of particle transit, chromium was utilized as a marker to mark the fiber. Passage rates were determined by retrieving the markers in the feces of the animals. In the degradation assay, samples were incubated in nylon bags for 0, 6, 18, 48 and 96 hours. The behavior observed in the regression curves of the variables analyzed describes high correlation between them, i.e., the time during which the silage is retained in the rumen influences its digestibility and its degradation rate. Although the silage compacted at 900 kg/m³ shows a larger potentially digestible fraction, it is recommended that it be ensiled at a compaction density of approximately 750 kg/m³ due to the lower cost and shorter mean retention time in the rumen-reticulum and rumen fill, thereby increasing the ruminal degradation and passage dynamics.

  12. Pre-hospital transfusion of packed red blood cells in 147 patients from a UK helicopter emergency medical service.

    Science.gov (United States)

    Lyon, Richard M; de Sausmarez, Eleanor; McWhirter, Emily; Wareham, Gary; Nelson, Magnus; Matthies, Ashley; Hudson, Anthony; Curtis, Leigh; Russell, Malcolm Q

    2017-02-14

    Early transfusion of packed red blood cells (PRBC) has been associated with improved survival in patients with haemorrhagic shock. This study aims to describe the characteristics of patients receiving pre-hospital blood transfusion and evaluate their subsequent need for in-hospital transfusion and surgery. The decision to administer a pre-hospital PRBC transfusion was based on clinical judgment. All patients transfused pre-hospital PRBC between February 2013 and December 2014 were included. Pre-hospital and in-hospital records were retrospectively reviewed. One hundred forty-seven patients were included. 142 patients had traumatic injuries and 5 patients had haemorrhagic shock from a medical origin. Median Injury Severity Score was 30. 90% of patients receiving PRBC had an ISS of >15. Patients received a mean of 2.4(±1.1) units of PRBC in the pre-hospital phase. Median time from initial emergency call to hospital arrival was 114 min (IQR 103-140). There was significant improvement in systolic (p Pre-hospital transfusion of packed red cells has the potential to improvde outcome for trauma patients with major haemorrhage. The pre-hospital time for trauma patients can be several hours, suggesting transfusion needs to start in the pre-hospital phase. Hospital transfusion research suggests a 1:1 ratio of packed red blood cells to plasma improves outcome and further research into pre-hospital adoption of this strategy is needed. Pre-hospital PRBC transfusion significantly reduces the time to transfusion for major trauma patients with suspected major haemorrhage. The majority of patients receiving pre-hospital PRBC were severely injured and required further transfusion in hospital. Further research is warranted to determine which patients are most likely to have outcome benefit from pre-hospital blood products and what triggers should be used for pre-hospital transfusion.

  13. Pack Up

    OpenAIRE

    Strømberg, Sebastian

    2013-01-01

    Dette projekt tager udgangspunkt i en målgruppe afprøvning af Pack Up. Pack Up er en prototype af en app, der omhandler at skabe et community for backpacker, hvor man kan interagere med hinanden og mødes mens man er på farten. Igennem projektet vil det belyses hvorvidt app'en dækker målgruppens behov, og om udformningen af produktet som en app, er hensigtmæssigt i forhold til målgruppen. Dette vil ske af en analyse ud fra den indsamlede empiri, hvor Preben Sepstrups1 målgruppe teori inddrages...

  14. Density-Gradient Determination of Osmotic Potential in Plant Cells

    Science.gov (United States)

    Nabors, Murray W.

    1973-01-01

    Describes a method for measuring osmotic potential which is suitable for high school and college biology classes. This method introduces students to the hard-to-visualize technique of using density gradients to separate cells or cell constituents of differing densities. (JR)

  15. Effectiveness of a nursing intervention during transfusion of packed red cells on the patient´s anxiety state receiver

    Directory of Open Access Journals (Sweden)

    Jesús Fernando Martín Díaz

    2012-05-01

    Full Text Available The transfusion provokes anxiety and this one compromises the improvement of the patient. Objetive: The study aims to evaluate whether a nursing intervention protocol-through oral and written submissions previous to the transfusion of packed red blood cells decreases anxiety levels in pretransfusion and postransfusion recipient patients through a randomized clinical trial. Methodology: Be conducted in patients over 18 years admitted in the Hospitable complex of Toledo, prescription transfusion of packed red blood cells. For an alpha error 0.05, beta error of 0.90, with an expected effect of 10%, need 70 subjects in each group. The allocation to the intervention group and the control group was randomly made simple. The performance in the normal control group will be done in the hospital, patients receiving transfusion. As dependent variables evaluated:- The anxiety level pretransfusion and postransfusion. Using the questionnaire was validated by Spielberger (STAI. - The level of satisfaction perceived by the user on the information received prior to transfusion. By design developed for this study. Also recorded other control variables: sex, age, socio-cultural level, marital status, reason for transfusion, or no knowledge of the prescription of transfusion, incidents during transfusion.Scientific and sociosanitary relevancy of the study: The results will allow to know if the transfusion increases the anxiety and if an educational intervention nurse can diminish it; and to do the intervention before every transfusion.

  16. Power Packing

    Centers for Disease Control (CDC) Podcasts

    2011-08-16

    In this podcast for kids, the Kidtastics talk about how to pack a lunch safely, to help keep you from getting sick.  Created: 8/16/2011 by National Center for Emerging and Zoonotic Infectious Diseases (NCEZID).   Date Released: 8/16/2011.

  17. Packing Smart

    Centers for Disease Control (CDC) Podcasts

    2011-08-22

    In this podcast for kids, the Kidtastics talk about packing a lunch that's not boring and is full of the power and energy kids need to make it through the day.  Created: 8/22/2011 by National Center for Emerging and Zoonotic Infectious Diseases (NCEZID).   Date Released: 8/22/2011.

  18. Cell Density Plays a Critical Role in Ex Vivo Expansion of T Cells for Adoptive Immunotherapy

    Directory of Open Access Journals (Sweden)

    Qiangzhong Ma

    2010-01-01

    Full Text Available The successful ex vivo expansion of a large numbers of T cells is a prerequisite for adoptive immunotherapy. In this study, we found that cell density had important effects on the process of expansion of T cells in vitro. Resting T cells were activated to expand at high cell density but failed to be activated at low cell density. Activated T cells (ATCs expanded rapidly at high cell density but underwent apoptosis at low cell density. Our studies indicated that low-cell-density related ATC death is mediated by oxidative stress. Antioxidants N-acetylcysteine, catalase, and albumin suppressed elevated reactive oxygen species (ROS levels in low-density cultures and protected ATCs from apoptosis. The viability of ATCs at low density was preserved by conditioned medium from high-density cultures of ATCs in which the autocrine survival factor was identified as catalase. We also found that costimulatory signal CD28 increases T cell activation at lower cell density, paralleled by an increase in catalase secretion. Our findings highlight the importance of cell density in T cell activation, proliferation, survival and apoptosis and support the importance of maintaining T cells at high density for their successful expansion in vitro.

  19. Multiphysics Based Thermal Modeling of a Pouch Lithium-Ion Battery Cell for the Development of Pack Level Thermal Management System

    DEFF Research Database (Denmark)

    Khan, Mohammad Rezwan; Kær, Søren Knudsen

    2016-01-01

    The research is focused on the development of a three-dimensional cell level multiphysics battery thermal model. The primary aim is to represent the cooling mechanism inside the unit cell battery pack. It is accomplished through the coupling of heat transfer and computational fluid dynamics (CFD)...

  20. A ten liter stacked microbial desalination cell packed with mixed ion-exchange resins for secondary effluent desalination.

    Science.gov (United States)

    Zuo, Kuichang; Cai, Jiaxiang; Liang, Shuai; Wu, Shijia; Zhang, Changyong; Liang, Peng; Huang, Xia

    2014-08-19

    The architecture and performance of microbial desalination cell (MDC) have been significantly improved in the past few years. However, the application of MDC is still limited in a scope of small-scale (milliliter) reactors and high-salinity-water desalination. In this study, a large-scale (>10 L) stacked MDC packed with mixed ion-exchange resins was fabricated and operated in the batch mode with a salt concentration of 0.5 g/L NaCl, a typical level of domestic wastewater. With circulation flow rate of 80 mL/min, the stacked resin-packed MDC (SR-MDC) achieved a desalination efficiency of 95.8% and a final effluent concentration of 0.02 g/L in 12 h, which is comparable with the effluent quality of reverse osmosis in terms of salinity. Moreover, the SR-MDC kept a stable desalination performance (>93%) when concentrate volume decreased from 2.4 to 0.1 L (diluate/concentrate volume ratio increased from 1:1 to 1:0.04), where only 0.875 L of nonfresh water was consumed to desalinate 1 L of saline water. In addition, the SR-MDC achieved a considerable desalination rate (95.4 mg/h), suggesting a promising application for secondary effluent desalination through deriving biochemical electricity from wastewater.

  1. Corneal endothelial cell density and morphology in healthy Turkish eyes.

    Science.gov (United States)

    Arıcı, Ceyhun; Arslan, Osman Sevki; Dikkaya, Funda

    2014-01-01

    Purpose. To describe the normative values of corneal endothelial cell density, morphology, and central corneal thickness in healthy Turkish eyes. Methods. Specular microscopy was performed in 252 eyes of 126 healthy volunteers (M : F, 42 : 84). Parameters studied included mean endothelial cell density (MCD), mean cell area (MCA), coefficient of variation (CV) in cell size, percentage of hexagonal cells, and central corneal thickness (CCT). Results. The mean age of volunteers was 44.3 ± 13.5 (range, 20 to 70) years. There was a statistically significant decrease in MCD (P Filipino eyes and higher than that described in Indian, Thai, and Iranian eyes.

  2. A thermal packed-bed reactor and a silent discharge plasma cell for a two-stage treatment system

    International Nuclear Information System (INIS)

    Godoy-Cabrera, O G; Lopez-Callejas, R; Mercado-Cabrera, A; Barocio, S R; Valencia, R; Munoz-Castro, A; Eguiluz, R Pena; Piedad-Beneitez, A de la

    2006-01-01

    Dielectric barrier discharge cells (DBDCs) have proved their efficiency in the generation of cold plasmas for hazardous organic compound degradation. Here, we describe the design and construction of a dual thermal packed-bed reactor and DBDC-based system to carry out the degradation of hazardous organic compounds in both liquid and gas phases. The main components of this system are: (i) the thermal treatment system (ii) DBDC and (iii) resonant inverters of low (3.3 kHz) and high (100 kHz) calculated frequencies. The definition of the cell physical parameters considers: (a) a first-order degradation ratio of the compound and (b) the air breakdown at atmospheric pressure as a function of the transport carrier gas. The power consumed by the cells during the discharges was computed theoretically and experimentally. Using the dual system along with a gas chromatography diagnostic system, highly efficient degradations of a test compound (benzene) have been obtained, reaching 99.950% in the case of a cell experimentally operated at 3.3 kHz and up to 99.996% in another one at 94.3 kHz. An additional 3.7 times reduction in the latter case residence time with respect to the low frequency cell has been found

  3. Assessment of clinical and laboratory variables as a guide to packed red blood cell transfusion of euvolemic anemic dogs.

    Science.gov (United States)

    Kisielewicz, C; Self, I; Bell, R

    2014-01-01

    There are no standardized guidelines for determining the likelihood that euvolemic anemic dogs will benefit from transfusion of packed red blood cells (pRBC). To report clinical and laboratory variables of dogs receiving pRBC transfusion, which could guide transfusion of other anemic dogs. Twenty-four client-owned anemic dogs receiving pRBC transfusion. Prospective study; 30 transfusions assessed. Clinical findings (mucosal color, pulse quality, heart rate, respiratory rate, mentation/exercise tolerance) before and after transfusion were evaluated by the anemic dog clinical assessment score (ADCAS). Hemoglobin concentration, hematocrit, venous oxygen content (CvO2 ), and lactate concentration were measured from blood samples taken before and after transfusion. These results were not used for case management. All ADCAS variables decreased significantly with transfusion (P dogs with similar presentations. Copyright © 2014 by the American College of Veterinary Internal Medicine.

  4. Successful implementation of a packed red blood cell and fresh frozen plasma transfusion protocol in the surgical intensive care unit.

    Directory of Open Access Journals (Sweden)

    Benjamin E Szpila

    Full Text Available Blood product transfusions are associated with increased morbidity and mortality. The purpose of this study was to determine if implementation of a restrictive protocol for packed red blood cell (PRBC and fresh frozen plasma (FFP transfusion safely reduces blood product utilization and costs in a surgical intensive care unit (SICU.We performed a retrospective, historical control analysis comparing before (PRE and after (POST implementation of a restrictive PRBC/FFP transfusion protocol for SICU patients. Univariate analysis was utilized to compare patient demographics and blood product transfusion totals between the PRE and POST cohorts. Multivariate logistic regression models were developed to determine if implementation of the restrictive transfusion protocol is an independent predictor of adverse outcomes after controlling for age, illness severity, and total blood products received.829 total patients were included in the analysis (PRE, n=372; POST, n=457. Despite higher mean age (56 vs. 52 years, p=0.01 and APACHE II scores (12.5 vs. 11.2, p=0.006, mean units transfused per patient were lower for both packed red blood cells (0.7 vs. 1.2, p=0.03 and fresh frozen plasma (0.3 vs. 1.2, p=0.007 in the POST compared to the PRE cohort, respectively. There was no difference in inpatient mortality between the PRE and POST cohorts (7.5% vs. 9.2%, p=0.39. There was a decreased risk of urinary tract infections (OR 0.47, 95%CI 0.28-0.80 in the POST cohort after controlling for age, illness severity and amount of blood products transfused.Implementation of a restrictive transfusion protocol can effectively reduce blood product utilization in critically ill surgical patients with no increase in morbidity or mortality.

  5. Effect of Monocular Deprivation on Rabbit Neural Retinal Cell Densities.

    Science.gov (United States)

    Mwachaka, Philip Maseghe; Saidi, Hassan; Odula, Paul Ochieng; Mandela, Pamela Idenya

    2015-01-01

    To describe the effect of monocular deprivation on densities of neural retinal cells in rabbits. Thirty rabbits, comprised of 18 subject and 12 control animals, were included and monocular deprivation was achieved through unilateral lid suturing in all subject animals. The rabbits were observed for three weeks. At the end of each week, 6 experimental and 3 control animals were euthanized, their retinas was harvested and processed for light microscopy. Photomicrographs of the retina were taken and imported into FIJI software for analysis. Neural retinal cell densities of deprived eyes were reduced along with increasing period of deprivation. The percentage of reductions were 60.9% (P < 0.001), 41.6% (P = 0.003), and 18.9% (P = 0.326) for ganglion, inner nuclear, and outer nuclear cells, respectively. In non-deprived eyes, cell densities in contrast were increased by 116% (P < 0.001), 52% (P < 0.001) and 59.6% (P < 0.001) in ganglion, inner nuclear, and outer nuclear cells, respectively. In this rabbit model, monocular deprivation resulted in activity-dependent changes in cell densities of the neural retina in favour of the non-deprived eye along with reduced cell densities in the deprived eye.

  6. On contact numbers in random rod packings

    NARCIS (Netherlands)

    Wouterse, A.; Luding, Stefan; Philipse, A.P.

    2009-01-01

    Random packings of non-spherical granular particles are simulated by combining mechanical contraction and molecular dynamics, to determine contact numbers as a function of density. Particle shapes are varied from spheres to thin rods. The observed contact numbers (and packing densities) agree well

  7. Li-Ion Pouch Cells for Vehicle Applications — Studies of Water Transmission and Packing Materials

    Directory of Open Access Journals (Sweden)

    Göran Flodberg

    2013-01-01

    Full Text Available This study includes analysis of encapsulation materials from lithium-ion pouch cells and water vapour transmission rate (WVTR measurements. WVTR measurements are performed on both fresh and environmentally stressed lithium-ion pouch cells. Capacity measurements are performed on both the fresh and the environmentally stressed battery cells to identify possible influences on electrochemical performance. Preparation of the battery cells prior to WVTR measurements includes opening of battery cells and extraction of electrode material, followed by resealing the encapsulations and adhesively mounting of gas couplings. A model describing the water diffusion through the thermal welds of the encapsulation are set up based on material analysis of the encapsulation material. Two WVTR equipments with different type of detectors are evaluated in this study. The results from the WVTR measurements show how important it is to perform this type of studies in dry environment and apply a rigorous precondition sequence before testing. Results from modelling confirm that the WVTR method has potential to be used for measurements of water diffusion into lithium-ion pouch cells. Consequently, WVTR measurements should be possible to use as a complement or alternative method to for example Karl Fisher titration.

  8. Use of the Primitive Unit Cell in Understanding Subtle Features of the Cubic Closest-Packed Structure

    Science.gov (United States)

    Hawkins, John A.; Rittenhouse, Jeffrey L.; Soper, Linda M.; Rittenhouse, Robert C.

    2008-01-01

    One of the most important crystal structures adopted by metals is characterized by the "abcabc"...stacking of close-packed layers. This structure is commonly referred to in textbooks as the cubic close-packed (ccp) or face-centered cubic (fcc) structure, since the entire lattice can be generated by replication of a face-centered cubic unit cell…

  9. Simulation of the Battery Pack Exploitation Based on Real Measurement Data of Applied Chemical Cells

    Directory of Open Access Journals (Sweden)

    Koniak Marcin

    2016-01-01

    Full Text Available Authors of following article present the method of battery work simulation based on real measurement data of applied chemical cells and workload data. Description of method as its assumptions are presented. Next authors present workplace designed and constructed for acquiring operating characteristics according to assumed research plan. Article introduces computer system responsible for running simulations. At the end of publication results of selected runs are presented. Also described are types of tested cells and means of acquiring data concerning battery workload. Article ends with summarization and approximate plans of method development.

  10. Anorexia Reduces GFAP+ Cell Density in the Rat Hippocampus.

    Science.gov (United States)

    Reyes-Haro, Daniel; Labrada-Moncada, Francisco Emmanuel; Varman, Durairaj Ragu; Krüger, Janina; Morales, Teresa; Miledi, Ricardo; Martínez-Torres, Ataúlfo

    2016-01-01

    Anorexia nervosa is an eating disorder observed primarily in young women. The neurobiology of the disorder is unknown but recently magnetic resonance imaging showed a volume reduction of the hippocampus in anorexic patients. Dehydration-induced anorexia (DIA) is a murine model that mimics core features of this disorder, including severe weight loss due to voluntary reduction in food intake. The energy supply to the brain is mediated by astrocytes, but whether their density is compromised by anorexia is unknown. Thus, the aim of this study was to estimate GFAP+ cell density in the main regions of the hippocampus (CA1, CA2, CA3, and dentate gyrus) in the DIA model. Our results showed that GFAP+ cell density was significantly reduced (~20%) in all regions of the hippocampus, except in CA1. Interestingly, DIA significantly reduced the GFAP+ cells/nuclei ratio in CA2 (-23%) and dentate gyrus (-48%). The reduction of GFAP+ cell density was in agreement with a lower expression of GFAP protein. Additionally, anorexia increased the expression of the intermediate filaments vimentin and nestin. Accordingly, anorexia increased the number of reactive astrocytes in CA2 and dentate gyrus more than twofold. We conclude that anorexia reduces the hippocampal GFAP+ cell density and increases vimentin and nestin expression.

  11. Association of Age and Packed Red Blood Cell Transfusion to One-Year Survival- an Observational Study of ICU Patients

    Science.gov (United States)

    Mudumbai, Seshadri C.; Cronkite, Ruth; Unger-Hu, Kirsten; Heidenreich, Paul; Gonzalez, Chris; Bertaccini, Edward; Stafford, Randall; Cason, Brian; Mariano, Edward R.; Wagner, Todd

    2014-01-01

    Objectives To compare the 1-year survival for different age strata of intensive care unit (ICU) patients after receipt of packed red blood cell (PRBC) transfusions. Background Despite guidelines documenting risks of PRBC transfusion and data showing that increasing age is associated with ICU mortality, little data exist on whether age alters the transfusion-related risk of decreased survival. Methods We retrospectively examined data on 2393 consecutive male ICU patients admitted to a tertiary-care hospital from 2003 to 2009 in age strata: 21–50, 51–60, 61–70, 71–80, and >80 years. We calculated Cox regression models to determine the modifying effect of age on the impact of PRBC transfusion on 1-year survival by using interaction terms between receipt of transfusion and age strata, controlling for type of admission and Charlson co-morbidity indices. We also examined the distribution of admission haematocrit and whether transfusion rates differed by age strata. Results All age strata experienced statistically similar risks of decreased 1-year survival after receipt of PRBC transfusions. However, patients age >80 were more likely than younger cohorts to have hematocrits of 25– 30% at admission and were transfused at approximately twice the rate of each of the younger age strata. Discussion We found no significant interaction between receipt of red cell transfusion and age, as variables, and survival at 1 year as an outcome. PMID:23480030

  12. Packing and Disorder in Substituted Fullerenes

    KAUST Repository

    Tummala, Naga Rajesh

    2016-07-15

    Fullerenes are ubiquitous as electron-acceptor and electron-transport materials in organic solar cells. Recent synthetic strategies to improve the solubility and electronic characteristics of these molecules have translated into a tremendous increase in the variety of derivatives employed in these applications. Here, we use molecular dynamics (MD) simulations to examine the impact of going from mono-adducts to bis- and tris-adducts on the structural, cohesive, and packing characteristics of [6,6]-phenyl-C60-butyric acid methyl ester (PCBM) and indene-C60. The packing configurations obtained at the MD level then serve as input for density functional theory calculations that examine the solid-state energetic disorder (distribution of site energies) as a function of chemical substitution. The variations in structural and site-energy disorders reflect the fundamental materials differences among the derivatives and impact the performance of these materials in thin-film electronic devices.

  13. Corneal Endothelial Cell Density and Morphology in Healthy Turkish Eyes

    Directory of Open Access Journals (Sweden)

    Ceyhun Arıcı

    2014-01-01

    Full Text Available Purpose. To describe the normative values of corneal endothelial cell density, morphology, and central corneal thickness in healthy Turkish eyes. Methods. Specular microscopy was performed in 252 eyes of 126 healthy volunteers (M : F, 42 : 84. Parameters studied included mean endothelial cell density (MCD, mean cell area (MCA, coefficient of variation (CV in cell size, percentage of hexagonal cells, and central corneal thickness (CCT. Results. The mean age of volunteers was 44.3±13.5 (range, 20 to 70 years. There was a statistically significant decrease in MCD (P<0.001; correlation, −0.388 and percentage of hexagonal cells, (P<0.001; correlation, −0.199 with age. There was also a statistically significant increase in MCA (P<0.001; correlation, 0.363 with increasing age. There was no statistically significant difference in MCD, MCA, CV in cell size, percentage of hexagonal cells, and CCT between genders and there was also no significant difference in these parameters between fellow eyes of subjects. Conclusions. Normotive data for the endothelium in the Turkish population are reported. Endothelial cell density in the Turkish eyes is less than that described in the Japanese, American, Chinese, and Filipino eyes and higher than that described in Indian, Thai, and Iranian eyes.

  14. Effect of Packed Red Blood Cell Cryopreservation on Development of the Storage Lesion and Inflammation

    Science.gov (United States)

    2015-09-01

    data sources, gathering and maintaining the data needed, and completing and reviewing this collection of information. Send comments regarding this...thawed red cells. Transfusion. 1992; 32(4):344-348. 9. Valeri CR, Brodine CE, Moss GE. Use of frozen blood in Vietnam. Bibl Haematol. 1968; 29:735

  15. Density of pack-ice seals and penguins in the western Weddell Sea in relation to ice thickness and ocean depth

    NARCIS (Netherlands)

    Florentino De Souza Silva, A.P.; Haas, C.; Franeker, van J.A.; Meesters, H.W.G.

    2008-01-01

    Aerial band transect censuses were carried out parallel with ice thickness profiling surveys in the pack ice of the western Weddell Sea during the ISPOL (Ice Station POLarstern) expedition of R.V. Polarstern from November 2004 to January 2005. Three regions were surveyed: the deep sea of the Weddell

  16. Solid Oxide Electrolysis Cells: Degradation at High Current Densities

    DEFF Research Database (Denmark)

    Knibbe, Ruth; Traulsen, Marie Lund; Hauch, Anne

    2010-01-01

    The degradation of Ni/yttria-stabilized zirconia (YSZ)-based solid oxide electrolysis cells operated at high current densities was studied. The degradation was examined at 850°C, at current densities of −1.0, −1.5, and −2.0 A/cm2, with a 50:50 (H2O:H2) gas supplied to the Ni/YSZ hydrogen electrode...

  17. High power density yeast catalyzed microbial fuel cells

    Science.gov (United States)

    Ganguli, Rahul

    Microbial fuel cells leverage whole cell biocatalysis to convert the energy stored in energy-rich renewable biomolecules such as sugar, directly to electrical energy at high efficiencies. Advantages of the process include ambient temperature operation, operation in natural streams such as wastewater without the need to clean electrodes, minimal balance-of-plant requirements compared to conventional fuel cells, and environmentally friendly operation. These make the technology very attractive as portable power sources and waste-to-energy converters. The principal problem facing the technology is the low power densities compared to other conventional portable power sources such as batteries and traditional fuel cells. In this work we examined the yeast catalyzed microbial fuel cell and developed methods to increase the power density from such fuel cells. A combination of cyclic voltammetry and optical absorption measurements were used to establish significant adsorption of electron mediators by the microbes. Mediator adsorption was demonstrated to be an important limitation in achieving high power densities in yeast-catalyzed microbial fuel cells. Specifically, the power densities are low for the length of time mediator adsorption continues to occur. Once the mediator adsorption stops, the power densities increase. Rotating disk chronoamperometry was used to extract reaction rate information, and a simple kinetic expression was developed for the current observed in the anodic half-cell. Since the rate expression showed that the current was directly related to microbe concentration close to the electrode, methods to increase cell mass attached to the anode was investigated. Electrically biased electrodes were demonstrated to develop biofilm-like layers of the Baker's yeast with a high concentration of cells directly connected to the electrode. The increased cell mass did increase the power density 2 times compared to a non biofilm fuel cell, but the power density

  18. Shape-controlled high cell-density microcapsules by electrodeposition.

    Science.gov (United States)

    Liu, Zeyang; Takeuchi, Masaru; Nakajima, Masahiro; Hasegawa, Yasuhisa; Huang, Qiang; Fukuda, Toshio

    2016-06-01

    Cell encapsulation within alginate-poly-l-lysine (PLL) microcapsules has been developed to provide a miniaturized three-dimensional (3D) microenvironment with an aqueous core while promoting development of encapsulated cells into high cell-density structures. In this paper, a novel method for fabricating shape-controlled alginate-PLL microcapsules to construct 3D cell structures based on electrodeposition method is provided. Two-dimensional Ca-alginate cell-laden gel membranes were electrodeposited onto a micro-patterned electrode and further detached from the electrode. The PLL was coated onto the gel structures to form alginate-PLL complex as an outer shell and sodium citric solution was utilized to melt the internal alginate to achieve miniaturized 3D microcapsules (sphere, cuboid, and rod shape). By this proposed method, rat liver cells (RLC-18) formed multi-cellular aggregates with high cell-density after cultivation for 2weeks. The use of alginate-poly-l-lysine (PLL) microcapsules has shown great potential in fabricating 3D cell structures with high cell density. Despite their success related to their ability to provide a miniaturized microenvironment with an aqueous core, alginate-PLL microcapsules has drawback such as a limited shape-control ability. Because of the mechanism of Ca-induced alginate gel formation, it is still difficult to precisely control the gelation process to produce alginate-PLL microcapsules with specific shape. The present study provides an electrodeposition-based method to generate shape-controlled microcapsules for 3D cell structures. Sphere, cuboid, and rod shaped microcapsules of RLC-18 cells were produced for long-term culture to obtain desired morphologies of cell aggregates. Copyright © 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  19. Packed red blood cell transfusion causes greater hemoglobin rise at a lower starting hemoglobin in patients with subarachnoid hemorrhage.

    Science.gov (United States)

    Naidech, Andrew M; Kahn, Marc J; Soong, Wayne; Green, David; Batjer, H Hunt; Bleck, Thomas P

    2008-01-01

    Each unit of packed red blood cells (PRBCs) is expected to raise circulating hemoglobin (HGB) by approximately 1 g/dL. There are few data on modifiers of this relationship other than gender and body mass index (BMI). We recorded HGB before and after PRBC transfusion in a retrospective cohort of 103 patients and a prospective cohort of 93 patients with subarachnoid hemorrhage (SAH). In the retrospective cohort, 48 of 103 patients were transfused, and in the prospective cohort, 56 of 93 patients were transfused. In both groups, lower pre-transfusion HGB was associated with a larger increase in HGB (P rise in HGB (P < 0.001) after correction for number of units of PRBCs given, gender, and BMI in repeated measures analysis. Pre-transfusion HGB explained an additional 12% of variance in the data (P < 0.001). In both cohorts, the magnitude of the effect was similar. In patients with SAH, transfusion at lower HGB leads to a greater increase in HGB. Transfusion at lower HGB may be relatively more cost-effective, and this should be balanced against any potential benefit from higher HGB in SAH. One rather than 2 units of PRBCs are likely to be sufficient for most HGB targets after SAH, especially in patients with more severe anemia.

  20. Relationship between blood group, packed cell volume, knowledge and practices of adults to malaria prevalence in Lagos Island, Nigeria

    Directory of Open Access Journals (Sweden)

    Bamidele Akinsanya

    2016-10-01

    Full Text Available Objective: To determine malaria prevalence, knowledge, attitude and practices at residents of Lagos Island Local Government. Methods: Two hundred blood samples were collected from adults attending the General Hospital, Marina while 100 questionnaires were administered to individuals still in the same hospital. Majority of the respondents were between the ages of 18 and 30 years (44%, while the age group 60 and above had the lowest population (9%. Results: More than half of the respondents (68% were employed and engaged in different occupations such as entrepreneur (32%, students (31%, trader (24%, and civil servant (10%. Stratification of the respondents by income revealed that 71% earned above the minimum wage, while 29% earned below. The prevalence of malaria by microscopy method was 10.5%. Malaria parasite had significant effect on the packed cell volume of infected individuals (P < 0.05. Preventive measures employed by the respondents were majorly insecticide (72.2%, while some others (5.6% used mosquito net. Majority of the respondents (98% believed that malaria was caused by mosquito. Conclusions: Therefore, it is appropriate to put in place preventive measures against malaria to avoid high prevalence of the number one killer in tropical Africa.

  1. Suppressing Energy Loss due to Triplet Exciton Formation in Organic Solar Cells: The Role of Chemical Structures and Molecular Packing

    KAUST Repository

    Chen, Xiankai

    2017-04-21

    In the most efficient solar cells based on blends of a conjugated polymer (electron donor) and a fullerene derivative (electron acceptor),ultrafast formation of charge-transfer (CT) electronic states at the donor-acceptor interfaces and efficient separation of these CT states into free charges, lead to internal quantum efficiencies near 100%. However, there occur substantial energy losses due to the non-radiative recombinations of the charges, mediated by the loweset-energy (singlet and triplet) CT states; for example, such recombinations can lead to the formation of triplet excited electronic states on the polymer chains, which do not generate free charges. This issue remains a major factor limiting the power conversion efficiencies (PCE) of these devices. The recombination rates are, however, difficult to quantify experimentally. To shed light on these issues, here, an integrated multi-scale theoretical approach that combines molecular dynamics simulations with quantum chemistry calculations is employed in order to establish the relationships among chemical structures, molecular packing, and non-radiative recombination losses mediated by the lowest-energy charge-transfer states.

  2. Competitive migration behaviors of multiple ions and their impacts on ion-exchange resin packed microbial desalination cell.

    Science.gov (United States)

    Zuo, Kuichang; Yuan, Lulu; Wei, Jincheng; Liang, Peng; Huang, Xia

    2013-10-01

    Mixed ion-exchange resins packed microbial desalination cell (R-MDC) could stabilize the internal resistance, however, the impacts of multiple ions on R-MDC performance was unclear. This study investigated the desalination performance, multiple ions migration behaviors and their impacts on R-MDCs fed with salt solution containing multiple anions and cations. Results showed that R-MDC removed multiple anions better than multiple cations with desalination efficiency of 99% (effluent conductivity NO3(-)>Cl(-) for anions and Ca(2+)≈Mg(2+)>NH4(+)>Na(+) for cations, jointly affected by both their molar conductivity and exchange selectivity on resins. After long-term operation, the existence of higher concentration Ca(2+) and Mg(2+) caused the electric conductivity of mixed resins decrease and scaling on the surface of cation-exchange membrane adjoined with cathode chamber, suggesting that R-MDC would be more suitable for desalination of water with lower hardness. Copyright © 2013 Elsevier Ltd. All rights reserved.

  3. Comparison between hemoglobin and packed cell volume among young male and female students from a Medical College of Islamabad, Pakistan

    International Nuclear Information System (INIS)

    Zia, Q.U.A.

    2015-01-01

    To high light the importance of laboratory investigations for students and encourage them to participate in research. Methodology: This cross sectional study was carried out at Islamabad Medical and Dental College Islamabad for a three months period from April 1, 2014 to June 30, 2014. Students with age 18-20 years were chosen by convenience sampling for sample collection. Verbal consent was taken from candidates before sample collection. Packed cell volume (PCV) was measured by using Micro Hematocrit method and hemoglobin (Hb) concentration by Sahli acid haematin method. Data were analyzed using SPSS version 20. Results: Out of 106 students, there were 32 males and 74 females. Male participants had significantly greater Hb concentration and PCV as compared to females (p=0.05). Conclusion: Both Hb and PCV were significantly higher in males as compared to females of almost same age. For improving Hb concentration, dietary sources of iron and iron supplements may be used for better health of future generation. (author)

  4. Any Defining Role of Mast Cell or Mast Cell Density in Oral ...

    African Journals Online (AJOL)

    Any Defining Role of Mast Cell or. Mast Cell Density in. Oral Squamous Cell. Carcinoma? Dear Sir,. I read an article by Zaidi et al. titled to “A study on assessment of mast cell (MCs) in oral squamous cell carcinoma (OSCC)” with great interest.[1] We are concerned about their meandering conclusion presuming close ...

  5. Measuring density and compressibility of white blood cells and prostate cancer cells by microchannel acoustophoresis

    DEFF Research Database (Denmark)

    Barnkob, Rune; Augustsson, Per; Magnusson, Cecilia

    2011-01-01

    to determine the density and compressibility of individual cells enables the prediction and alteration of the separation outcome for a given cell mixture. We apply the method on white blood cells (WBCs) and DU145 prostate cancer cells (DUCs) aiming to improve isolation of circulating tumor cells from blood......, an emerging tool in the monitoring and characterizing of metastatic cancer....

  6. Interaction of low density lipoproteins with rat liver cells

    NARCIS (Netherlands)

    L. Harkes (Leendert)

    1985-01-01

    textabstractThe most marked conclusion is the establishment of the important role of non-parenchymal cells in the catabolism of the low density lipoproteins by the rat liver. Because the liver is responsible for 70-80% of the removal of LDL from blood this conclusion can be extended to total

  7. Effect of cell density on adipogenic differentiation of mesenchymal stem cells

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Hongxu [Graduate School of Pure and Applied Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8577 (Japan); Biomaterials Center, National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan); Guo, Likun [Biomaterials Center, National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan); National Engineering Research Center for Biomaterials, Sichuan University, 29 Wangjiang Road, Chengdu 610064 (China); Wozniak, Michal J. [Biomaterials Center, National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan); Kawazoe, Naoki [Biomaterials Center, National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan); International Center for Materials Nanoarchitectonics (MANA), National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan); Tateishi, Tetsuya [Biomaterials Center, National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan); Zhang, Xingdong [National Engineering Research Center for Biomaterials, Sichuan University, 29 Wangjiang Road, Chengdu 610064 (China); Chen, Guoping, E-mail: Guoping.CHEN@nims.go.jp [Graduate School of Pure and Applied Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8577 (Japan); Biomaterials Center, National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan); International Center for Materials Nanoarchitectonics (MANA), National Institute for Materials Science, 1-1 Namiki, Tsukuba, Ibaraki 305-0044 (Japan)

    2009-04-10

    The effect of cell density on the adipogenic differentiation of human bone marrow-derived mesenchymal stem cells (MSCs) was investigated by using a patterning technique to induce the formation of a cell density gradient on a micropatterned surface. The adipogenic differentiation of MSCs at a density gradient from 5 x 10{sup 3} to 3 x 10{sup 4} cells/cm{sup 2} was examined. Lipid vacuoles were observed at all cell densities after 1-3 weeks of culture in adipogenic differentiation medium although the lipid vacuoles were scarce at the low cell density and abundant at the high cell density. Real-time RT-PCR analysis showed that adipogenesis marker genes encoding peroxisome proliferator-activated receptor {gamma}2 (PPAR{gamma}2), lipoprotein lipase (LPL), and fatty acid binding protein-4 (FABP4) were detected in the MSCs cultured at all cell densities. The results suggest that there was no apparent effect of cell density on the adipogenic differentiation of human MSCs.

  8. Packing of sedimenting equiaxed dendrites

    Science.gov (United States)

    Olmedilla, Antonio; Založnik, Miha; Rouat, Bernard; Combeau, Hervé

    2018-01-01

    The packing of free-floating crystal grains during solidification has a strong impact on the phase-change process as well as on the structure and the defects in the solidified material. The packing fraction is affected by the particular dendritic morphology of the grains and by their low inertia resulting from the small density difference between solid and liquid. Understanding the grain packing phenomenon during metal alloy solidification is not experimentally possible since packing is coupled to many other phenomena. We therefore investigate the packing of equiaxed dendrites on a model system, consisting of fixed-shape nonconvex model particles sedimenting in conditions hydrodynamically similar to those encountered in solidifying metals. We perform numerical simulations by a discrete-element model and experiments with transparent liquids in a sedimentation column. The combination of experiments and simulations enables us to determine the packing fraction as a function of (i) the grain morphology, expressed by a shape parameter, and (ii) the hydrodynamic conditions, expressed by the particle Stokes number.

  9. Cell density overrides the effect of substrate stiffness on human mesenchymal stem cells' morphology and proliferation.

    Science.gov (United States)

    Venugopal, Balu; Mogha, Pankaj; Dhawan, Jyotsna; Majumder, Abhijit

    2018-03-12

    The effect of substrate stiffness on the cellular morphology, proliferation, and differentiation of human mesenchymal stem cells (hMSCs) has been extensively researched and well established. However, the majority of these studies are done with a low seeding density where cell to cell interactions do not play a significant role. While these conditions permit an analysis of cell-substratum interactions at the single cell level, such a model system fails to capture a critical aspect of the cellular micro-environment in vivo, i.e. the cell-cell interaction via matrix deformation (i.e., strain). To address this question, we seeded hMSCs on soft poly-acrylamide (PAA) gels, at a seeding density that permits cells to be mechanically interacting via the underlying substrate. We found that as the intercellular distance decreases with the increasing seeding density, cellular sensitivity towards the substrate rigidity becomes significantly diminished. With the increasing seeding density, the cell spread area increased on a soft substrate (500 Pa) but reduced on an even slightly stiffer substrate (2 kPa) as well as on glass making them indistinguishable at a high seeding density. Not only in terms of cell spread area but also at a high seeding density, cells formed mature focal adhesions and prominent stress fibres on a soft substrate similar to that of the cells being cultured on a stiff substrate. The decreased intercellular distance also influenced the proliferation rate of the cells: higher seeding density on the soft substrate showed cell cycle progression similar to that of the cells on glass substrates. In summary, this paper demonstrates how the effect of substrate rigidity on the cell morphology and fate is a function of inter-cellular distance when seeded on a soft substrate. Our AFM data suggest that such changes happen due to local strain stiffening of the soft PAA gel, an effect that has been rarely reported in the literature so far.

  10. Use of Esophageal Hemoximetry to Assess the Effect of Packed Red Blood Cell Transfusion on Gastrointestinal Oxygenation in Newborn Infants.

    Science.gov (United States)

    Vora, Farha M; Gates, Judy; Gerard, Kimberley; Hanson, Shawn; Applegate, Richard L; Blood, Arlin B

    2017-07-01

    Objectives  There are no widely accepted methods of continuously monitoring gut oxygenation in the newborn during packed red blood cell transfusion. We investigated the use of an orally inserted light spectroscopy probe to measure lower esophageal oxyhemoglobin saturations (eStO 2 ) before, during, and after transfusion and made comparisons with abdominal near-infrared spectroscopy (NIRS) and superior mesenteric artery (SMA) flow. Study Design  Thirteen neonates with corrected gestational ages ranging from 22 weeks, 0 day to 37 weeks, 5 days were enrolled. eStO 2 and NIRS measurements were recorded continuously for a 25-hour period starting 1 hour prior to starting the 4-hour transfusion. Transabdominal ultrasound was used to measure SMA flow prior to, upon completion, and 20 hours after the transfusion. Results  Twelve infants completed the study. eStO 2 was well-tolerated and was weakly (r = 0.06) correlated ( p  NIRS. Compared with NIRS, eStO 2 demonstrated a markedly greater variation in oxyhemoglobin values. NIRS and SMA flow measurements did not change, while eStO 2 increased from 48 ± 5% and 45 ± 5% in the pre- and intratransfusion periods to 57 ± 4% in the posttransfusion period ( p  = 0.03). Conclusion  Measurement of eStO 2 is feasible in neonates and may provide a continuous and sensitive index of rapid changes in mesenteric oxygenation in this patient population. Thieme Medical Publishers 333 Seventh Avenue, New York, NY 10001, USA.

  11. Surface determinants of low density lipoprotein uptake by endothelial cells

    International Nuclear Information System (INIS)

    Goeroeg, P.; Pearson, J.D.

    1984-01-01

    The surface sialic acid content of aortic endothelial cells in vitro was substantially lower in sparse cultures than at confluence. Binding of LDL to endothelial cells did not change at different culture densities and was unaffected by brief pretreatment with neuraminidase to partially remove surface sialic acid residues. In contrast, internalisation of LDL declined by a factor of 3 between low density cell cultures and confluent monolayers; neuraminidase pretreatment increased LDL uptake and the effect was most marked (>10-fold) at confluence. Pretreatment with cationised ferritin, which removed most of the surface sialic acid residues as well as glycosaminoglycans, increased LDL internalisation by up to 20-fold, again with most effect on confluent monolayers. Thus LDL uptake is inversely correlated with sialic acid content. We conclude that changes in the surface density of sialic acid (and possibly other charged) residues significantly modulate endothelial LDL uptake, and suggest that focal increases in LDL accumulation during atherogenesis may be related to alterations in endothelial endocytic properties at sites of increased cell turnover or damage. (author)

  12. The pursuit of perfect packing

    CERN Document Server

    Weaire, Denis

    2008-01-01

    Coauthored by one of the creators of the most efficient space packing solution, the Weaire-Phelan structure, The Pursuit of Perfect Packing, Second Edition explores a problem of importance in physics, mathematics, chemistry, biology, and engineering: the packing of structures. Maintaining its mathematical core, this edition continues and revises some of the stories from its predecessor while adding several new examples and applications. The book focuses on both scientific and everyday problems ranging from atoms to honeycombs. It describes packing models, such as the Kepler conjecture, Voronoï decomposition, and Delaunay decomposition, as well as actual structure models, such as the Kelvin cell and the Weaire-Phelan structure. The authors discuss numerous historical aspects and provide biographical details on influential contributors to the field, including emails from Thomas Hales and Ken Brakke. With examples from physics, crystallography, engineering, and biology, this accessible and whimsical bo...

  13. Symmetry and coplanarity of organic molecules affect their packing and photovoltaic properties in solution-processed solar cells.

    Science.gov (United States)

    Lan, Shang-Che; Raghunath, Putikam; Lu, Yueh-Hsin; Wang, Yi-Chien; Lin, Shu-Wei; Liu, Chih-Ming; Jiang, Jian-Ming; Lin, Ming-Chang; Wei, Kung-Hwa

    2014-06-25

    In this study we synthesized three acceptor-donor-acceptor (A-D-A) organic molecules, TB3t-BT, TB3t-BTT, and TB3t-BDT, comprising 2,2'-bithiophene (BT), benzo[1,2-b:3,4-b':5,6-d″]trithiophene (BTT), and benzo[1,2-b;4,5-b']dithiophene (BDT) units, respectively, as central cores (donors), terthiophene (3t) as π-conjugated spacers, and thiobarbituric acid (TB) units as acceptors. These molecules display different degrees of coplanarity as evidenced by the differences in dihedral angles calculated from density functional theory. By using differential scanning calorimetry and X-ray diffractions for probing their crystallization characteristics and molecular packing in active layers, we found that the symmetry and coplanarity of molecules would significantly affect the melting/crystallization behavior and the formation of crystalline domains in the blend film with fullerene, PC61BM. TB3t-BT and TB3t-BDT, which each possess an inversion center and display high crystallinity in their pristine state, but they have different driving forces in crystallization, presumably because of different degrees of coplanarity. On the other hand, the asymmetrical TB3t-BTT behaved as an amorphous material even though it possesses a coplanar structure. Among our tested systems, the device comprising as-spun TB3t-BDT/PC61BM (6:4, w/w) active layer featured crystalline domains and displayed the highest power conversion efficiency (PCE) of 4.1%. In contrast, the as-spun TB3t-BT/PC61BM (6:4, w/w) active layer showed well-mixed morphology and with a device PCE of 0.2%; it increased to 3.9% after annealing the active layer at 150 °C for 15 min. As for TB3t-BTT, it required a higher content of fullerene in the TB3t-BTT/PC61BM (4:6, w/w) active layer to optimize its device PCE to 1.6%.

  14. Nanofiber density determines endothelial cell behavior on hydrogel matrix

    Energy Technology Data Exchange (ETDEWEB)

    Berti, Fernanda V., E-mail: fernanda@intelab.ufsc.br [Department of Chemical and Food Engineering, Federal University of Santa Catarina, 88040-900 Florianópolis, SC (Brazil); Rambo, Carlos R. [Department of Electrical Engineering, Federal University of Santa Catarina, 88040-900 Florianópolis, SC (Brazil); Dias, Paulo F. [Department of Cell Biology, Embryology and Genetics, Federal University of Santa Catarina, 88040-900 Florianópolis, SC (Brazil); Porto, Luismar M. [Department of Chemical and Food Engineering, Federal University of Santa Catarina, 88040-900 Florianópolis, SC (Brazil)

    2013-12-01

    When cultured under static conditions, bacterial cellulose pellicles, by the nature of the polymer synthesis that involves molecular oxygen, are characterized by two distinct surface sides. The upper surface is denser in fibers (entangled) than the lower surface that shows greater surface porosity. Human umbilical vein endothelial cells (HUVECs) were used to exploit how the microarchitecture (i.e., surface porosity, fiber network structure, surface topology, and fiber density) of bacterial cellulose pellicle surfaces influence cell–biomaterial interaction and therefore cell behavior. Adhesion, cell ingrowth, proliferation, viability and cell death mechanisms were evaluated on the two pellicle surface sides. Cell behavior, including secondary necrosis, is influenced only by the microarchitecture of the surface, since the biomaterial is extremely pure (constituted of cellulose and water only). Cell–cellulose fiber interaction is the determinant signal in the cell–biomaterial responses, isolated from other frequently present interferences such as protein and other chemical traces usually present in cell culture matrices. Our results suggest that microarchitecture of hydrogel materials might determine the performance of biomedical products, such as bacterial cellulose tissue engineering constructs (BCTECs). - Highlights: • Topography of BC pellicle is relevant to determine endothelial cells' fate. • Cell–biomaterial response is affected by the topography of BC-pellicle surface. • Endothelial cells exhibit different behavior depending on the BC topography. • Apoptosis and necrosis of endothelial cells were affected by the BC topography.

  15. Nanofiber density determines endothelial cell behavior on hydrogel matrix

    International Nuclear Information System (INIS)

    Berti, Fernanda V.; Rambo, Carlos R.; Dias, Paulo F.; Porto, Luismar M.

    2013-01-01

    When cultured under static conditions, bacterial cellulose pellicles, by the nature of the polymer synthesis that involves molecular oxygen, are characterized by two distinct surface sides. The upper surface is denser in fibers (entangled) than the lower surface that shows greater surface porosity. Human umbilical vein endothelial cells (HUVECs) were used to exploit how the microarchitecture (i.e., surface porosity, fiber network structure, surface topology, and fiber density) of bacterial cellulose pellicle surfaces influence cell–biomaterial interaction and therefore cell behavior. Adhesion, cell ingrowth, proliferation, viability and cell death mechanisms were evaluated on the two pellicle surface sides. Cell behavior, including secondary necrosis, is influenced only by the microarchitecture of the surface, since the biomaterial is extremely pure (constituted of cellulose and water only). Cell–cellulose fiber interaction is the determinant signal in the cell–biomaterial responses, isolated from other frequently present interferences such as protein and other chemical traces usually present in cell culture matrices. Our results suggest that microarchitecture of hydrogel materials might determine the performance of biomedical products, such as bacterial cellulose tissue engineering constructs (BCTECs). - Highlights: • Topography of BC pellicle is relevant to determine endothelial cells' fate. • Cell–biomaterial response is affected by the topography of BC-pellicle surface. • Endothelial cells exhibit different behavior depending on the BC topography. • Apoptosis and necrosis of endothelial cells were affected by the BC topography

  16. Effect of Monocular Deprivation on Rabbit Neural Retinal Cell Densities

    OpenAIRE

    Mwachaka, Philip Maseghe; Saidi, Hassan; Odula, Paul Ochieng; Mandela, Pamela Idenya

    2015-01-01

    Purpose: To describe the effect of monocular deprivation on densities of neural retinal cells in rabbits. Methods: Thirty rabbits, comprised of 18 subject and 12 control animals, were included and monocular deprivation was achieved through unilateral lid suturing in all subject animals. The rabbits were observed for three weeks. At the end of each week, 6 experimental and 3 control animals were euthanized, their retinas was harvested and processed for light microscopy. Photomicrographs of ...

  17. Cell density, negative proliferation control, and phosphorylation of retinoblastoma protein.

    Science.gov (United States)

    Böhmer, R M

    1993-04-01

    Cell density negative control (CDNC) of normal human fibroblast proliferation occurs after stimulation by mitogens with different signal transduction mechanism. Delayed exposure to agents that interfere with CDNC, such as double-stranded RNA and vanadate, reveals the existence of a biochemical event, involved in CDNC, that occurs 5-8 hr after the beginning of mitogenic stimulation. This is earlier than the point of "mitogenic commitment," defined by the duration of mitogen exposure required for cell cycle entry (8-18 hr). Phosphorylation of the retinoblastoma gene product (pRB) begins 8-10 hr after mitogen stimulation and is nearly complete at 18 hr, just as the first cells enter S-phase. CDNC prevents pRB phosphorylation. Interferon beta delays pRB phosphorylation by up to 20 hr but has little effect on the timing of mitogenic commitment. Thus mitogenic commitment is located in time between CDNC and pRB phosphorylation. When agents that cause a release from CDNC are applied to dense, negatively controlled cultures after 18 hr of EGF stimulation, pRB phosphorylation occurs 6-8 hr after release. This suggests that the negatively controlled cells process the mitogenic signal but accumulate at a restriction point. The relatively early timing of CDNC-related events in the prereplicative phase raises the possibility that pRB phosphorylation is a consequence rather than a prerequisite for release from cell density negative control.

  18. Blood parasites, total plasma protein and packed cell volume of small wild mammals trapped in three mountain ranges of the Atlantic Forest in Southeastern Brazil.

    Science.gov (United States)

    Silva, M A M L; Ronconi, A; Cordeiro, N; Bossi, D E P; Bergallo, H G; Costa, M C C; Balieiro, J C C; Varzim, F L S B

    2007-08-01

    A study of blood parasites in small wild non-flying mammals was undertaken in three areas of the Atlantic Forest in Southeastern Brazil: Serra de Itatiaia, RJ, Serra da Bocaina, SP and Serra da Fartura, SP, from June 1999 to May 2001. A total of 450 animals (15 species) were captured in traps and it was observed in 15.5% of the blood smears the presence of Haemobartonella sp. and Babesia sp. in red blood cells. There was no statistically significant difference between parasited and non-parasited specimens regarding total plasma protein, packed cell volume and body weight, which strongly suggests that these specimens might be parasite reservoirs.

  19. Effect of age on heart rate, blood lactate concentration, packed cell volume and hemoglobin to exercise in Jeju crossbreed horses

    Directory of Open Access Journals (Sweden)

    Ok-Deuk Kang

    2017-01-01

    Full Text Available Abstract Background This study aimed to analyze the on heart rate, blood lactate concentration, packed cell volume (PCV and hemoglobin (Hb response after conducting exercise in endurance horses. Methods A total of 20 healthy 3–9-years-old Jeju crossbreed mares (5.95 ± 2.24 year of age and 312.65 ± 13.59 kg of weight currently participating the endurance competition were used. The field tests selected for the experiment was gallop (approximately 8.3 m/s along the selected 2.5 km course (a natural forest trail, not artificial road; a closed loop course. The horses were divided into three groups according to their age; 3–4 years of age (G1, 3.29 ± 0.49 year, 6–7 years of age (G2, 6.42 ± 0.53, and 8–9 years of age (G3, 8.50 ± 0.55. The measurements times for the heart rate, blood lactate concentration, PCV, and Hb analysis were conducted before exercise (T0, shortly after exercise (T1, 15 min after exercise (T2, and 30 min after exercise (T3, respectively. Data was analyzed using an analysis of covariance (ANCOVA for repeated measures with times and groups. Results The results of the comparison depending on the passage of rest time after exercise suggest that the heart rate and blood lactate concentration of three groups at T2 significantly decreased compared to T1 (p < 0.001. PCV of the G2 and G3 groups were significantly decreased at T2 compared to T1 (p < 0.01. Hb values at G2 (p < 0.01 and G3 (p < 0.001 groups were significantly decreased at T2 as compared to T1. However, heart rate, blood lactate concentration, PCV and Hb level at T1 showed no difference in the comparison of horses from different age groups with the exception of G3 group in terms of heart rate. Conclusion The physiologic and hematological responses of horses during recovery time after 2,500 m exercise with gallop were no significant difference among the groups. These data are useful as a response evaluation method for

  20. ExactPack Documentation

    Energy Technology Data Exchange (ETDEWEB)

    Singleton, Robert Jr. [Los Alamos National Laboratory; Israel, Daniel M. [Los Alamos National Laboratory; Doebling, Scott William [Los Alamos National Laboratory; Woods, Charles Nathan [Los Alamos National Laboratory; Kaul, Ann [Los Alamos National Laboratory; Walter, John William Jr [Los Alamos National Laboratory; Rogers, Michael Lloyd [Los Alamos National Laboratory

    2016-05-09

    For code verification, one compares the code output against known exact solutions. There are many standard test problems used in this capacity, such as the Noh and Sedov problems. ExactPack is a utility that integrates many of these exact solution codes into a common API (application program interface), and can be used as a stand-alone code or as a python package. ExactPack consists of python driver scripts that access a library of exact solutions written in Fortran or Python. The spatial profiles of the relevant physical quantities, such as the density, fluid velocity, sound speed, or internal energy, are returned at a time specified by the user. The solution profiles can be viewed and examined by a command line interface or a graphical user interface, and a number of analysis tools and unit tests are also provided. We have documented the physics of each problem in the solution library, and provided complete documentation on how to extend the library to include additional exact solutions. ExactPack’s code architecture makes it easy to extend the solution-code library to include additional exact solutions in a robust, reliable, and maintainable manner.

  1. Calculation of the close packing of fine aggregate on the basis of ...

    African Journals Online (AJOL)

    The paper considers the calculation of the maximum packing density of fine aggregate. The selection of the granulometric composition of the aggregate is given. The bulk densities and packing densities of standard screening fractions were determined. The content of each fraction in the mixture and the packing density of ...

  2. Quorum sensing integrates environmental cues, cell density and cell history to control bacterial competence.

    Science.gov (United States)

    Moreno-Gámez, Stefany; Sorg, Robin A; Domenech, Arnau; Kjos, Morten; Weissing, Franz J; van Doorn, G Sander; Veening, Jan-Willem

    2017-10-11

    Streptococcus pneumoniae becomes competent for genetic transformation when exposed to an autoinducer peptide known as competence-stimulating peptide (CSP). This peptide was originally described as a quorum-sensing signal, enabling individual cells to regulate competence in response to population density. However, recent studies suggest that CSP may instead serve as a probe for sensing environmental cues, such as antibiotic stress or environmental diffusion. Here, we show that competence induction can be simultaneously influenced by cell density, external pH, antibiotic-induced stress, and cell history. Our experimental data is explained by a mathematical model where the environment and cell history modify the rate at which cells produce or sense CSP. Taken together, model and experiments indicate that autoinducer concentration can function as an indicator of cell density across environmental conditions, while also incorporating information on environmental factors or cell history, allowing cells to integrate cues such as antibiotic stress into their quorum-sensing response. This unifying perspective may apply to other debated quorum-sensing systems.Peptide CSP regulates natural competence in pneumococci and has been proposed as a quorum-sensing signal or a probe for sensing environmental cues. Here, the authors show that CSP levels can indeed act as an indicator of cell density and also incorporate information on environmental factors or cell history.

  3. Fluid flow plate for decreased density of fuel cell assembly

    Science.gov (United States)

    Vitale, Nicholas G.

    1999-01-01

    A fluid flow plate includes first and second outward faces. Each of the outward faces has a flow channel thereon for carrying respective fluid. At least one of the fluids serves as reactant fluid for a fuel cell of a fuel cell assembly. One or more pockets are formed between the first and second outward faces for decreasing density of the fluid flow plate. A given flow channel can include one or more end sections and an intermediate section. An interposed member can be positioned between the outward faces at an interface between an intermediate section, of one of the outward faces, and an end section, of that outward face. The interposed member can serve to isolate the reactant fluid from the opposing outward face. The intermediate section(s) of flow channel(s) on an outward face are preferably formed as a folded expanse.

  4. Quantification of cell density in rat Achilles tendon

    DEFF Research Database (Denmark)

    Couppé, Christian; Svensson, René B; Heinemeier, Katja M

    2017-01-01

    Increased tendon cell nuclei density (TCND) has been proposed to induce tendon mechanical adaptations. However, it is unknown whether TCND is increased in tendon tissue after mechanical loading and whether such an increase can be quantified in a reliable manner. The aim of this study was to develop...... a reliable method for quantification of TCND and to investigate potential changes in TCND in rat Achilles tendons in response to 12 weeks of running. Eight adult male Sprague-Dawley rats ran (RUN) on a treadmill with 10° incline, 1 h/day, 5 days/wk (17-20 m/min) for 12 weeks (which improved tendon mechanical...... properties) and were compared with 11 control rats (SED). Tissue-Tek-embedded cryosections (10 µm) from the mid region of the Achilles tendon were cut longitudinally on a cryostat. Sections were stained with alcian blue and picrosirius red. One blinded investigator counted the number of tendon cell nuclei 2...

  5. Corneal endothelial cell density and morphology in Phramongkutklao Hospital

    Directory of Open Access Journals (Sweden)

    Narumon Sopapornamorn

    2008-03-01

    Full Text Available Narumon Sopapornamorn1, Manapon Lekskul1, Suthee Panichkul21Department of Ophthalmology, Phramongkutklao Hospital, Bangkok, Thailand; 2Department of Obstetrics and Gynecology, Phramongkutklao College of Medicine, Bangkok, ThailandObjective: To describe the corneal endothelial density and morphology in patients of Phramongkutklao Hospital and the relationship between endothelial cell parameters and other factors.Methods: Four hundred and four eyes of 202 volunteers were included. Noncontact specular microscopy was performed after taking a history and testing the visual acuity, intraocular pressure measurement, Schirmer’s test and routine eye examination by slit lamp microscope. The studied parameters included mean endothelial cell density (MCD, coefficient of variation (CV, and percentage of hexagonality.Results: The mean age of volunteers was 45.73 years; the range being 20 to 80 years old. Their MCD (SD, mean percentage of CV (SD and mean (SD percentage of hexagonality were 2623.49(325 cell/mm2, 39.43(8.23% and 51.50(10.99%, respectively. Statistically, MCD decreased significantly with age (p < 0.01. There was a significant difference in the percentage of CV between genders. There was no statistical significance between parameters and other factors.Conclusion: The normative data of the corneal endothelium of Thai eyes indicated that, statistically, MCD decreased significantly with age. Previous studies have reported no difference in MCD, percentage of CV, and percentage of hexagonality between gender. Nevertheless, significantly different percentages of CV between genders were presented in this study.Keywords: Corneal endothelial cell, parameters, age, gender, smoking, Thailand

  6. Flexible and Lightweight Fuel Cell with High Specific Power Density.

    Science.gov (United States)

    Ning, Fandi; He, Xudong; Shen, Yangbin; Jin, Hehua; Li, Qingwen; Li, Da; Li, Shuping; Zhan, Yulu; Du, Ying; Jiang, Jingjing; Yang, Hui; Zhou, Xiaochun

    2017-06-27

    Flexible devices have been attracting great attention recently due to their numerous advantages. But the energy densities of current energy sources are still not high enough to support flexible devices for a satisfactory length of time. Although proton exchange membrane fuel cells (PEMFCs) do have a high-energy density, traditional PEMFCs are usually too heavy, rigid, and bulky to be used in flexible devices. In this research, we successfully invented a light and flexible air-breathing PEMFC by using a new design of PEMFC and a flexible composite electrode. The flexible air-breathing PEMFC with 1 × 1 cm 2 working area can be as light as 0.065 g and as thin as 0.22 mm. This new PEMFC exhibits an amazing specific volume power density as high as 5190 W L -1 , which is much higher than traditional (air-breathing) PEMFCs. Also outstanding is that the flexible PEMFC retains 89.1% of its original performance after being bent 600 times, and it retains its original performance after being dropped five times from a height of 30 m. Moreover, the research has demonstrated that when stacked, the flexible PEMFCs are also useful in mobile applications such as mobile phones. Therefore, our research shows that PEMFCs can be made light, flexible, and suitable for applications in flexible devices. These innovative flexible PEMFCs may also notably advance the progress in the PEMFC field, because flexible PEMFCs can achieve high specific power density with small size, small volume, low weight, and much lower cost; they are also much easier to mass produce.

  7. Measuring density and compressibility of white blood cells and prostate cancer cells by microchannel acoustophoresis

    DEFF Research Database (Denmark)

    Barnkob, Rune; Augustsson, Per; Magnusson, Cecilia

    2011-01-01

    We present a novel method for the determination of density and compressibility of individual particles and cells undergoing microchannel acoustophoresis in an arbitrary 2D acoustic field. Our method is a critical advancement within acoustophoretic separation of biological cells, as the ability to...

  8. Enrichment of unlabeled human Langerhans cells from epidermal cell suspensions by discontinuous density gradient centrifugation

    NARCIS (Netherlands)

    Teunissen, M. B.; Wormmeester, J.; Kapsenberg, M. L.; Bos, J. D.

    1988-01-01

    In this report we introduce an alternative procedure for enrichment of human epidermal Langerhans cells (LC) from epidermal cell suspensions of normal skin. By means of discontinuous Ficoll-Metrizoate density gradient centrifugation, a fraction containing high numbers of viable, more than 80% pure

  9. Mapping cellular processes in the mesenchyme during palatal development in the absence of Tbx1 reveals complex proliferation changes and perturbed cell packing and polarity.

    Science.gov (United States)

    Brock, Lara J; Economou, Andrew D; Cobourne, Martyn T; Green, Jeremy B A

    2016-03-01

    The 22q11 deletion syndromes represent a spectrum of overlapping conditions including cardiac defects and craniofacial malformations. Amongst the craniofacial anomalies that are seen, cleft of the secondary palate is a common feature. Haploinsufficiency of TBX1 is believed to be a major contributor toward many of the developmental structural anomalies that occur in these syndromes, and targeted deletion of Tbx1 in the mouse reproduces many of these malformations, including cleft palate. However, the cellular basis of this defect is only poorly understood. Here, palatal development in the absence of Tbx1 has been analysed, focusing on cellular properties within the whole mesenchymal volume of the palatal shelves. Novel image analyses and data presentation tools were applied to quantify cell proliferation rates, including regions of elevated as well as reduced proliferation, and cell packing in the mesenchyme. Also, cell orientations (nucleus-Golgi axis) were mapped as a potential marker of directional cell movement. Proliferation differed only subtly between wild-type and mutant until embryonic day (E)15.5 when proliferation in the mutant was significantly lower. Tbx1(-/-) palatal shelves had slightly different cell packing than wild-type, somewhat lower before elevation and higher at E15.5 when the wild-type palate has elevated and fused. Cell orientation is biased towards the shelf distal edge in the mid-palate of wild-type embryos but is essentially random in the Tbx1(-/-) mutant shelves, suggesting that polarised processes such as directed cell rearrangement might be causal for the cleft phenotype. The implications of these findings in the context of further understanding Tbx1 function during palatogenesis and of these methods for the more general analysis of genotype-phenotype functional relationships are discussed. © 2015 The Authors. Journal of Anatomy published by John Wiley & Sons Ltd on behalf of Anatomical Society.

  10. The Effect of Shear Rate on Dissolution of Gas and Cell Density in Continuous Foaming Process

    Directory of Open Access Journals (Sweden)

    M.H.N. Famili

    2009-12-01

    Full Text Available The effect of shear rate on dissolution of carbon dioxide in viscoelastic wheat flour matrix and cell density in a glass barrel twin screw extruder is investigated. It is found that by increasing the shear rate there will be a decrease in the required thermodynamic conditions and hence, it improves blowing agent dissolution and increases the cell density. Shear rate breaks up big bubbles and helps to better distribute the blowing agent in the matrix and hence it increases the cell density. Cell density decreases by dropping foam cooling rate. For a given cell density, a higher screw speed is needed, ifthe cooling rate is decreased.

  11. Prediction of Packed Cell Volume after Whole Blood Transfusion in Small Ruminants and South American Camelids: 80 Cases (2006-2016).

    Science.gov (United States)

    Luethy, D; Stefanovski, D; Salber, R; Sweeney, R W

    2017-11-01

    Calculation of desired whole blood transfusion volume relies on an estimate of an animal's circulating blood volume, generally accepted to be 0.08 L/kg or 8% of the animal's body weight in kilograms. To use packed cell volume before and after whole blood transfusion to evaluate the accuracy of a commonly used equation to predict packed cell volume after transfusion in small ruminants and South American camelids; to determine the nature and frequency of adverse transfusion reactions in small ruminants and camelids after whole blood transfusion. Fifty-eight small ruminants and 22 alpacas that received whole blood transfusions for anemia. Retrospective case series; medical record review for small ruminants and camelids that received whole blood transfusions during hospitalization. Mean volume of distribution of blood as a fraction of body weight in sheep (0.075 L/kg, 7.5% BW) and goats (0.076 L/kg, 7.6% BW) differed significantly (P camelids is low. Copyright © 2017 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals, Inc. on behalf of the American College of Veterinary Internal Medicine.

  12. Degradation of high density lipoprotein in cultured rat luteal cells

    International Nuclear Information System (INIS)

    Rajan, V.P.; Menon, K.M.J.

    1986-01-01

    In rat ovary luteal cells, degradation of high density lipoprotein (HDL) to tricholoracetic acid (TCA)-soluble products accounts for only a fraction of the HDL-derived cholesterol used for steroidogenesis. In this study the authors have investigated the fate of 125 I]HDL bound to cultured luteal cells using pulse-chase technique. Luteal cell cultures were pulse labeled with [ 125 I]HDL 3 and reincubated in the absence of HDL. By 24 h about 50% of the initallay bound radioactivity was released into the medium, of which 60-65% could be precipitated with 10% TCA. Gel filtration of the chase incubation medium on 10% agarose showed that the amount of TCA-soluble radioactivity was nearly completely accounted for by a sharp peak in the low molecular weight region which was identified as 96% monoiodotyrosine by paper chromatography. The TCA-precipitable radioactivity was nearly completely accounted for by a sharp peak in the low molecular weight region which was identified as 96% monoiodotyrosine by paper chromatography. The TCA-precipitable radioactivity eluted over a wide range of molecular weights (15,000-80,000), and there was very little intact HDL present. Electrophoresis of the chase medium showed that component of the TCA-precipitable portion had mobility similar to apo AI. Lysosomal inhibitors of receptor-mediated endocytosis had no effect on the composition or quantity of radioactivity released during chase incubation. The results show that HDL 3 binding to luteal cells is followed by complete degradation of the lipoprotein, although the TCA-soluble part does not reflect the extent of degradation

  13. Blood parasites, total plasma protein and packed cell volume of small wild mammals trapped in three mountain ranges of the Atlantic Forest in Southeastern Brazil

    Directory of Open Access Journals (Sweden)

    MAML. Silva

    Full Text Available A study of blood parasites in small wild non-flying mammals was undertaken in three areas of the Atlantic Forest in Southeastern Brazil: Serra de Itatiaia, RJ, Serra da Bocaina, SP and Serra da Fartura, SP, from June 1999 to May 2001. A total of 450 animals (15 species were captured in traps and it was observed in 15.5% of the blood smears the presence of Haemobartonella sp. and Babesia sp. in red blood cells. There was no statistically significant difference between parasited and non-parasited specimens regarding total plasma protein, packed cell volume and body weight, which strongly suggests that these specimens might be parasite reservoirs.

  14. Tunable random packings

    International Nuclear Information System (INIS)

    Lumay, G; Vandewalle, N

    2007-01-01

    We present an experimental protocol that allows one to tune the packing fraction η of a random pile of ferromagnetic spheres from a value close to the lower limit of random loose packing η RLP ≅0.56 to the upper limit of random close packing η RCP ≅0.64. This broad range of packing fraction values is obtained under normal gravity in air, by adjusting a magnetic cohesion between the grains during the formation of the pile. Attractive and repulsive magnetic interactions are found to affect stongly the internal structure and the stability of sphere packing. After the formation of the pile, the induced cohesion is decreased continuously along a linear decreasing ramp. The controlled collapse of the pile is found to generate various and reproducible values of the random packing fraction η

  15. Packings of deformable spheres

    Science.gov (United States)

    Mukhopadhyay, Shomeek; Peixinho, Jorge

    2011-07-01

    We present an experimental study of disordered packings of deformable spheres. Fluorescent hydrogel spheres immersed in water together with a tomography technique enabled the imaging of the three-dimensional arrangement. The mechanical behavior of single spheres subjected to compression is first examined. Then the properties of packings of a randomized collection of deformable spheres in a box with a moving lid are tested. The transition to a state where the packing withstands finite stresses before yielding is observed. Starting from random packed states, the power law dependence of the normal force versus packing fraction or strain at different velocities is quantified. Furthermore, a compression-decompression sequence at low velocities resulted in rearrangements of the spheres. At larger packing fractions, a saturation of the mean coordination number took place, indicating the deformation and faceting of the spheres.

  16. Sociality in Escherichia coli: Enterochelin Is a Private Good at Low Cell Density and Can Be Shared at High Cell Density.

    Science.gov (United States)

    Scholz, Rebecca L; Greenberg, E Peter

    2015-07-01

    Many bacteria produce secreted iron chelators called siderophores, which can be shared among cells with specific siderophore uptake systems regardless of whether the cell produces siderophores. Sharing secreted products allows freeloading, where individuals use resources without bearing the cost of production. Here we show that the Escherichia coli siderophore enterochelin is not evenly shared between producers and nonproducers. Wild-type Escherichia coli grows well in low-iron minimal medium, and an isogenic enterochelin synthesis mutant (ΔentF) grows very poorly. The enterochelin mutant grows well in low-iron medium supplemented with enterochelin. At high cell densities the ΔentF mutant can compete equally with the wild type in low-iron medium. At low cell densities the ΔentF mutant cannot compete. Furthermore, the growth rate of the wild type is unaffected by cell density. The wild type grows well in low-iron medium even at very low starting densities. Our experiments support a model where at least some enterochelin remains associated with the cells that produce it, and the cell-associated enterochelin enables iron acquisition even at very low cell density. Enterochelin that is not retained by producing cells at low density is lost to dilution. At high cell densities, cell-free enterochelin can accumulate and be shared by all cells in the group. Partial privatization is a solution to the problem of iron acquisition in low-iron, low-cell-density habitats. Cell-free enterochelin allows for iron scavenging at a distance at higher population densities. Our findings shed light on the conditions under which freeloaders might benefit from enterochelin uptake systems. Sociality in microbes has become a topic of great interest. One facet of sociality is the sharing of secreted products, such as the iron-scavenging siderophores. We present evidence that the Escherichia coli siderophore enterochelin is relatively inexpensive to produce and is partially privatized such

  17. Smooth muscle myosin regulation by serum and cell density in cultured rat lung connective tissue cells.

    Science.gov (United States)

    Babij, P; Zhao, J; White, S; Woodcock-Mitchell, J; Mitchell, J; Absher, M; Baldor, L; Periasamy, M; Low, R B

    1993-08-01

    RNA and protein analyses were used to detect expression of SM1 and SM2 smooth muscle myosin heavy chain (MHC) in cultured adult rat lung connective tissue cells (RL-90). Smooth muscle MHC mRNA expression in confluent cells grown in 10% serum was approximately 50% of the level in adult stomach. Similar results were obtained in cells cultured at low density (25% confluency) in 1% serum. However, in low-density cultures transferred to 10% serum for 24 h, the level of MHC mRNA decreased to approximately 20% of that in adult stomach. Smooth muscle alpha-actin showed a pattern of expression similar to that for smooth muscle MHC. Expression of nonmuscle MHC-A mRNA was higher in all culture conditions compared to stomach. MHC-A mRNA expression was less in low-density cultures in low serum and increased when low-density cultures were transferred to 10% serum for 24 h. MHC-B mRNA expression was less in low- vs. high-density cultures. In contrast to MHC-A, however, MHC-B mRNA expression in low-density cultures was higher in low serum. Immunofluorescence and immunoblotting with SM1-specific antibody demonstrated the presence of the SM1 protein isoform as well as reactivity to a protein band migrating slightly faster than SM2. These results demonstrate that cultured rat lung connective tissue cells express smooth muscle MHC and that expression is modulated by culture conditions.

  18. Effects of hepatocyte growth factor on glutathione synthesis, growth, and apoptosis is cell density-dependent

    International Nuclear Information System (INIS)

    Yang Heping; Magilnick, Nathaniel; Xia Meng; Lu, Shelly C.

    2008-01-01

    Hepatocyte growth factor (HGF) is a potent hepatocyte mitogen that exerts opposing effects depending on cell density. Glutathione (GSH) is the main non-protein thiol in mammalian cells that modulates growth and apoptosis. We previously showed that GSH level is inversely related to cell density of hepatocytes and is positively related to growth. Our current work examined whether HGF can modulate GSH synthesis in a cell density-dependent manner and how GSH in turn influence HGF's effects. We found HGF treatment of H4IIE cells increased cell GSH levels only under subconfluent density. The increase in cell GSH under low density was due to increased transcription of GSH synthetic enzymes. This correlated with increased protein levels and nuclear binding activities of c-Jun, c-Fos, p65, p50, Nrf1 and Nrf2 to the promoter region of these genes. HGF acts as a mitogen in H4IIE cells under low cell density and protects against tumor necrosis factor α (TNFα)-induced apoptosis by limiting JNK activation. However, HGF is pro-apoptotic under high cell density and exacerbates TNFα-induced apoptosis by potentiating JNK activation. The increase in cell GSH under low cell density allows HGF to exert its full mitogenic effect but is not necessary for its anti-apoptotic effect

  19. Packing Degenerate Graphs Greedily

    Czech Academy of Sciences Publication Activity Database

    Allen, P.; Böttcher, J.; Hladký, J.; Piguet, Diana

    2017-01-01

    Roč. 61, August (2017), s. 45-51 ISSN 1571-0653 R&D Projects: GA ČR GJ16-07822Y Institutional support: RVO:67985807 Keywords : tree packing conjecture * graph packing * graph processes Subject RIV: BA - General Mathematics OBOR OECD: Pure mathematics

  20. Flat Pack Toy Design

    Science.gov (United States)

    Hutcheson, Brian

    2007-01-01

    In this article, the author introduces the concept of flat pack toys. Flat pack toys are designed using a template on a single sheet of letter-sized card stock paper. Before being cut out and built into a three-dimensional toy, they are scanned into the computer and uploaded to a website. With the template accessible from the website, anyone with…

  1. TLC Pack Unpacked

    Science.gov (United States)

    Oberhofer, Margret; Colpaert, Jozef

    2015-01-01

    TLC Pack stands for Teaching Languages to Caregivers and is a course designed to support migrants working or hoping to work in the caregiving sector. The TLC Pack resources range from A2 to B2 level of the Common European Framework of Reference for Languages (CEFR), and will be made available online in the six project languages: Dutch, English,…

  2. Estimation of immune cell densities in immune cell conglomerates: an approach for high-throughput quantification.

    Directory of Open Access Journals (Sweden)

    Niels Halama

    2009-11-01

    Full Text Available Determining the correct number of positive immune cells in immunohistological sections of colorectal cancer and other tumor entities is emerging as an important clinical predictor and therapy selector for an individual patient. This task is usually obstructed by cell conglomerates of various sizes. We here show that at least in colorectal cancer the inclusion of immune cell conglomerates is indispensable for estimating reliable patient cell counts. Integrating virtual microscopy and image processing principally allows the high-throughput evaluation of complete tissue slides.For such large-scale systems we demonstrate a robust quantitative image processing algorithm for the reproducible quantification of cell conglomerates on CD3 positive T cells in colorectal cancer. While isolated cells (28 to 80 microm(2 are counted directly, the number of cells contained in a conglomerate is estimated by dividing the area of the conglomerate in thin tissues sections (< or =6 microm by the median area covered by an isolated T cell which we determined as 58 microm(2. We applied our algorithm to large numbers of CD3 positive T cell conglomerates and compared the results to cell counts obtained manually by two independent observers. While especially for high cell counts, the manual counting showed a deviation of up to 400 cells/mm(2 (41% variation, algorithm-determined T cell numbers generally lay in between the manually observed cell numbers but with perfect reproducibility.In summary, we recommend our approach as an objective and robust strategy for quantifying immune cell densities in immunohistological sections which can be directly implemented into automated full slide image processing systems.

  3. Use of the mitochondria toxicity assay for quantifying the viable cell density of microencapsulated jurkat cells.

    Science.gov (United States)

    Werner, M; Biss, K; Jérôme, V; Hilbrig, F; Freitag, R; Zambrano, K; Hübner, H; Buchholz, R; Mahou, R; Wandrey, C

    2013-01-01

    The mitochondria toxicity assay (MTT assay) is an established method for monitoring cell viability based on mitochondrial activity. Here the MTT assay is proposed for the in situ quantification of the living cell density of microencapsulated Jurkat cells. Three systems were used to encapsulate the cells, namely a membrane consisting of an interpenetrating polyelectrolyte network of sodium cellulose sulphate/poly(diallyldimethylammonium chloride) (NaCS/PDADMAC), a calcium alginate hydrogel covered with poly(L-lysine) (Ca-alg-PLL), and a novel calcium alginate-poly(ethylene glycol) hybrid material (Ca-alg-PEG). MTT results were correlated to data obtained by the trypan blue exclusion assay after release of the cells from the NaCS/PDADMAC and Ca-alg-PLL capsules, while a resazurin-based assay was used for comparison in case of the Ca-alg-PEG material. Analysis by MTT assay allows quick and reliable determination of viable cell densities of encapsulated cells independent of the capsule material. The assay is highly reproducible with inter-assay relative standard deviations below 10%. © 2013 American Institute of Chemical Engineers.

  4. Packing force data correlations

    International Nuclear Information System (INIS)

    Heiman, S.M.

    1994-01-01

    One of the issues facing valve maintenance personnel today deals with an appropriate methodology for installing and setting valve packing that will minimize leak rates, yet ensure functionality of the the valve under all anticipated operating conditions. Several variables can affect a valve packing's ability to seal, such as packing bolt torque, stem finish, and lubrication. Stem frictional force can be an excellent overall indicator of some of the underlying conditions that affect the sealing characteristics of the packing and the best parameter to use when adjusting the packing. This paper addresses stem friction forces, analytically derives the equations related to these forces, presents a methodology for measuring these forces on valve stems, and attempts to correlate the data directly to the underlying variables

  5. Human endothelial progenitor cells internalize high-density lipoprotein.

    Directory of Open Access Journals (Sweden)

    Kaemisa Srisen

    Full Text Available Endothelial progenitor cells (EPCs originate either directly from hematopoietic stem cells or from a subpopulation of monocytes. Controversial views about intracellular lipid traffic prompted us to analyze the uptake of human high density lipoprotein (HDL, and HDL-cholesterol in human monocytic EPCs. Fluorescence and electron microscopy were used to investigate distribution and intracellular trafficking of HDL and its associated cholesterol using fluorescent surrogates (bodipy-cholesterol and bodipy-cholesteryl oleate, cytochemical labels and fluorochromes including horseradish peroxidase and Alexa Fluor® 568. Uptake and intracellular transport of HDL were demonstrated after internalization periods from 0.5 to 4 hours. In case of HDL-Alexa Fluor® 568, bodipy-cholesterol and bodipy-cholesteryl oleate, a photooxidation method was carried out. HDL-specific reaction products were present in invaginations of the plasma membrane at each time of treatment within endocytic vesicles, in multivesicular bodies and at longer periods of uptake, also in lysosomes. Some HDL-positive endosomes were arranged in form of "strings of pearl"- like structures. HDL-positive multivesicular bodies exhibited intensive staining of limiting and vesicular membranes. Multivesicular bodies of HDL-Alexa Fluor® 568-treated EPCs showed multilamellar intra-vacuolar membranes. At all periods of treatment, labeled endocytic vesicles and organelles were apparent close to the cell surface and in perinuclear areas around the Golgi apparatus. No HDL-related particles could be demonstrated close to its cisterns. Electron tomographic reconstructions showed an accumulation of HDL-containing endosomes close to the trans-Golgi-network. HDL-derived bodipy-cholesterol was localized in endosomal vesicles, multivesicular bodies, lysosomes and in many of the stacked Golgi cisternae and the trans-Golgi-network Internalized HDL-derived bodipy-cholesteryl oleate was channeled into the lysosomal

  6. The Effect of Shear Rate on Dissolution of Gas and Cell Density in Continuous Foaming Process

    OpenAIRE

    M.H.N. Famili; M. Ako

    2009-01-01

    The effect of shear rate on dissolution of carbon dioxide in viscoelastic wheat flour matrix and cell density in a glass barrel twin screw extruder is investigated. It is found that by increasing the shear rate there will be a decrease in the required thermodynamic conditions and hence, it improves blowing agent dissolution and increases the cell density. Shear rate breaks up big bubbles and helps to better distribute the blowing agent in the matrix and hence it increases the cell density. Ce...

  7. Daily variation in radiosensitivity of circulating blood cells and bone marrow cell density in mice

    International Nuclear Information System (INIS)

    Tabatabai, R.N.

    1984-01-01

    Mice on a 12/12 light/dark cycle were bled during a twenty-four hour period each week for eight weeks to establish daily values of circulating blood cells. No significant daily variation was found in total red blood cells, hematocrit, or percentage of reticulocytes. A significant (P < 0.001) daily variation was found in total white blood cells, with the minimum occurring at 8 PM and the maximum occurring during the daylight hours from 8 a.m. to 2 p.m. Mice were then exposed to 0 R, 20 R, 50 R, or 100 R of x-radiation to determine what dose significantly reduces the total white cell count in circulating blood. It was found that 100 R significantly (P < .05) reduces the total white cell count over a four week period post-exposure. To determine if circulating blood cells and bone marrow cells show a diurnal radiosensitivity, mice were exposed to 100 R or 200 R of x-radiation at noon or midnight. Hematocrits, reticulocyte and white blood cell counts, daily white blood cell rhythm, and bone marrow cell density indicate that these mice were more radiosensitive at night

  8. Information in a Network of Neuronal Cells: Effect of Cell Density and Short-Term Depression

    KAUST Repository

    Onesto, Valentina

    2016-05-10

    Neurons are specialized, electrically excitable cells which use electrical to chemical signals to transmit and elaborate information. Understanding how the cooperation of a great many of neurons in a grid may modify and perhaps improve the information quality, in contrast to few neurons in isolation, is critical for the rational design of cell-materials interfaces for applications in regenerative medicine, tissue engineering, and personalized lab-on-a-chips. In the present paper, we couple an integrate-and-fire model with information theory variables to analyse the extent of information in a network of nerve cells. We provide an estimate of the information in the network in bits as a function of cell density and short-term depression time. In the model, neurons are connected through a Delaunay triangulation of not-intersecting edges; in doing so, the number of connecting synapses per neuron is approximately constant to reproduce the early time of network development in planar neural cell cultures. In simulations where the number of nodes is varied, we observe an optimal value of cell density for which information in the grid is maximized. In simulations in which the posttransmission latency time is varied, we observe that information increases as the latency time decreases and, for specific configurations of the grid, it is largely enhanced in a resonance effect.

  9. Processing of stored packed red blood cells using autotransfusion devices decreases potassium and microaggregates: a prospective, randomized, single-blinded in vitro study.

    Science.gov (United States)

    Westphal-Varghese, B; Erren, M; Westphal, M; Van Aken, H; Ertmer, C; Lange, M; Booke, M

    2007-04-01

    The aim of the study was to compare the potential of autotransfusion devices to reduce non-infectious complications related to transfusion of long-stored packed red blood cells (PRBC; n= 57), such as changes in electrolytes, blood cells and the load of free microaggregates. Following a baseline measurement, a blood pool of three PRBC was divided into three equal volumes and washed with either the Haemonetics Cell Saver (HCS) or the continuous autotransfusion system (C.A.T.S), using the quality (CATS(quality)) and emergency (CATS(emergency)) mode. After the washing procedure, measurements for electrolytes, blood cells and free microaggregates were repeated (n= 19 each). Compared with baseline, the investigated autotransfusion devices reduced the median load of potassium (baseline: 52 mEq L(-1); HCS: 4 mEq L(-1); CATS(quality): 4 mEq L(-1); CATS(emergency): 17 mEq L(-1); each P glucose and protein. Whereas the quantity of microaggregates was not reduced by HCS, CATS(emergency) decreased the load of cell fragments below 7.8 microm (P CATS(quality) decreased the load of cell fragments not only to a diameter below 7.8 microm (P < 0.001 vs. baseline) but also of microaggregates between 7.8 and 17.6 microm (P < 0.05 vs. baseline). In situations where long-stored PRBC have to be transfused, the procedure described here may be feasible to reduce clinically relevant side effects, i.e. hyperkalaemia and microvascular obstruction secondary to free cell fragments. This approach could be especially useful in patients undergoing massive transfusion and/or suffering from renal failure.

  10. Optimal Packed String Matching

    DEFF Research Database (Denmark)

    Ben-Kiki, Oren; Bille, Philip; Breslauer, Dany

    2011-01-01

    In the packed string matching problem, each machine word accommodates – characters, thus an n-character text occupies n/– memory words. We extend the Crochemore-Perrin constantspace O(n)-time string matching algorithm to run in optimal O(n/–) time and even in real-time, achieving a factor – speedup...... over traditional algorithms that examine each character individually. Our solution can be efficiently implemented, unlike prior theoretical packed string matching work. We adapt the standard RAM model and only use its AC0 instructions (i.e., no multiplication) plus two specialized AC0 packed string...

  11. Graphitic packing removal tool

    Science.gov (United States)

    Meyers, Kurt Edward; Kolsun, George J.

    1997-01-01

    Graphitic packing removal tools for removal of the seal rings in one piece. he packing removal tool has a cylindrical base ring the same size as the packing ring with a surface finish, perforations, knurling or threads for adhesion to the seal ring. Elongated leg shanks are mounted axially along the circumferential center. A slit or slits permit insertion around shafts. A removal tool follower stabilizes the upper portion of the legs to allow a spanner wrench to be used for insertion and removal.

  12. Neuroendocrine cells during human prostate development: does neuroendocrine cell density remain constant during fetal as well as postnatal life?

    NARCIS (Netherlands)

    Xue, Y.; van der Laak, J.; Smedts, F.; Schoots, C.; Verhofstad, A.; de la Rosette, J.; Schalken, J.

    2000-01-01

    Knowledge concerning differentiation of neuroendocrine (NE) cells during development of the human prostate is rather fragmentary. Using immunohistochemistry combined with a morphometric method, we investigated the distribution and density of NE cells in the developing human prostate, with special

  13. Performance of conversion efficiency of a crystalline silicon solar cell with base doping density

    Directory of Open Access Journals (Sweden)

    Gokhan Sahin

    Full Text Available In this study, we investigate theoretically the electrical parameters of a crystalline silicon solar cell in steady state. Based on a one-dimensional modeling of the cell, the short circuit current density, the open circuit voltage, the shunt and series resistances and the conversion efficiency are calculated, taking into account the base doping density. Either the I-V characteristic, series resistance, shunt resistance and conversion efficiency are determined and studied versus base doping density. The effects applied of base doping density on these parameters have been studied. The aim of this work is to show how short circuit current density, open circuit voltage and parasitic resistances are related to the base doping density and to exhibit the role played by those parasitic resistances on the conversion efficiency of the crystalline silicon solar. Keywords: Crystalline silicon solar cell, Base doping density, Series resistance, Shunt resistance, Conversion efficiency

  14. Optimized packings with applications

    CERN Document Server

    Pintér, János

    2015-01-01

    This volume presents a selection of case studies that address a substantial range of optimized object packings (OOP) and their applications. The contributing authors are well-recognized researchers and practitioners. The mathematical modelling and numerical solution aspects of each application case study are presented in sufficient detail. A broad range of OOP problems are discussed: these include various specific and non-standard container loading and object packing problems, as well as the stowing of hazardous and other materials on container ships, data centre resource management, automotive engineering design, space station logistic support, cutting and packing problems with placement constraints, the optimal design of LED street lighting, robust sensor deployment strategies, spatial scheduling problems, and graph coloring models and metaheuristics for packing applications. Novel points of view related to model development and to computational nonlinear, global, mixed integer optimization and heuristic st...

  15. Internal state of granular assemblies near random close packing

    OpenAIRE

    Roux, Jean-Noël

    2004-01-01

    March 12, 2004; The structure of random sphere packings in mechanical equilibrium in prescribed stress states, as studied by molecular dynamics simulations, strongly depends on the assembling procedure. Frictionless packings in the limit of low pressure are devoid of dilatancy, and consequently share the same random close packing density, but exhibit fabric anisotropy related to stress anisotropy. Efficient compaction methods can be viewed as routes to circumvent the influence of friction. Si...

  16. Morphology of living cells cultured on nanowire arrays with varying nanowire densities and diameters.

    Science.gov (United States)

    Li, Zhen; Persson, Henrik; Adolfsson, Karl; Oredsson, Stina; Prinz, Christelle N

    2018-04-02

    Vertical nanowire arrays are increasingly investigated for their applications in steering cell behavior. The geometry of the array is an important parameter, which influences the morphology and adhesion of cells. Here, we investigate the effects of array geometry on the morphology of MCF7 cancer cells and MCF10A normal-like epithelial cells. Different gallium phosphide nanowire array-geometries were produced by varying the nanowire density and diameter. Our results show that the cell size is smaller on nanowires compared to flat gallium phosphide. The cell area decreases with increasing the nanowire density on the substrate. We observed an effect of the nanowire diameter on MCF10A cells, with a decreased cell area on 40 nm diameter nanowires, compared to 60 and 80 nm diameter nanowires in high-density arrays. The focal adhesion morphology depends on the extent to which cells are contacting the substrate. For low nanowire densities and diameters, cells are lying on the substrate and we observed large focal adhesions at the cell edges. In contrast, for high nanowire densities and diameters, cells are lying on top of the nanowires and we observed point-like focal adhesions distributed over the whole cell. Our results constitute a step towards the ability to fine-tune cell behavior on nanowire arrays.

  17. Statistical characterization of microstructure of packings of polydisperse hard cubes

    Science.gov (United States)

    Malmir, Hessam; Sahimi, Muhammad; Rahimi Tabar, M. Reza

    2017-05-01

    Polydisperse packings of cubic particles arise in several important problems. Examples include zeolite microcubes that represent catalytic materials, fluidization of such microcubes in catalytic reactors, fabrication of new classes of porous materials with precise control of their morphology, and several others. We present the results of detailed and extensive simulation and microstructural characterization of packings of nonoverlapping polydisperse cubic particles. The packings are generated via a modified random sequential-addition algorithm. Two probability density functions (PDFs) for the particle-size distribution, the Schulz and log-normal PDFs, are used. The packings are analyzed, and their random close-packing density is computed as a function of the parameters of the two PDFs. The maximum packing fraction for the highest degree of polydispersivity is estimated to be about 0.81, much higher than 0.57 for the monodisperse packings. In addition, a variety of microstructural descriptors have been calculated and analyzed. In particular, we show that (i) an approximate analytical expression for the structure factor of Percus-Yevick fluids of polydisperse hard spheres with the Schulz PDF also predicts all the qualitative features of the structure factor of the packings that we study; (ii) as the packings become more polydisperse, their behavior resembles increasingly that of an ideal system—"ideal gas"—with little or no correlations; and (iii) the mean survival time and mean relaxation time of a diffusing species in the packings increase with increasing degrees of polydispersivity.

  18. Density-gradient centrifugation enables the purification of cultured corneal endothelial cells for cell therapy by eliminating senescent cells

    Science.gov (United States)

    Okumura, Naoki; Kusakabe, Ayaka; Hirano, Hiroatsu; Inoue, Ryota; Okazaki, Yugo; Nakano, Shinichiro; Kinoshita, Shigeru; Koizumi, Noriko

    2015-01-01

    The corneal endothelium is essential for maintaining corneal transparency; therefore, corneal endothelial dysfunction causes serious vision loss. Tissue engineering-based therapy is potentially a less invasive and more effective therapeutic modality. We recently started a first-in-man clinical trial of cell-based therapy for treating corneal endothelial dysfunction in Japan. However, the senescence of corneal endothelial cells (CECs) during the serial passage culture needed to obtain massive quantities of cells for clinical use is a serious technical obstacle preventing the push of this regenerative therapy to clinical settings. Here, we show evidence from an animal model confirming that senescent cells are less effective in cell therapy. In addition, we propose that density-gradient centrifugation can eliminate the senescent cells and purify high potency CECs for clinical use. This simple technique might be applicable for other types of cells in the settings of regenerative medicine. PMID:26443440

  19. Flagellum density regulates Proteus mirabilis swarmer cell motility in viscous environments.

    Science.gov (United States)

    Tuson, Hannah H; Copeland, Matthew F; Carey, Sonia; Sacotte, Ryan; Weibel, Douglas B

    2013-01-01

    Proteus mirabilis is an opportunistic pathogen that is frequently associated with urinary tract infections. In the lab, P. mirabilis cells become long and multinucleate and increase their number of flagella as they colonize agar surfaces during swarming. Swarming has been implicated in pathogenesis; however, it is unclear how energetically costly changes in P. mirabilis cell morphology translate into an advantage for adapting to environmental changes. We investigated two morphological changes that occur during swarming--increases in cell length and flagellum density--and discovered that an increase in the surface density of flagella enabled cells to translate rapidly through fluids of increasing viscosity; in contrast, cell length had a small effect on motility. We found that swarm cells had a surface density of flagella that was ∼5 times larger than that of vegetative cells and were motile in fluids with a viscosity that inhibits vegetative cell motility. To test the relationship between flagellum density and velocity, we overexpressed FlhD(4)C(2), the master regulator of the flagellar operon, in vegetative cells of P. mirabilis and found that increased flagellum density produced an increase in cell velocity. Our results establish a relationship between P. mirabilis flagellum density and cell motility in viscous environments that may be relevant to its adaptation during the infection of mammalian urinary tracts and movement in contact with indwelling catheters.

  20. Collagen Matrix Density Drives the Metabolic Shift in Breast Cancer Cells

    Directory of Open Access Journals (Sweden)

    Brett A. Morris

    2016-11-01

    Full Text Available Increased breast density attributed to collagen I deposition is associated with a 4–6 fold increased risk of developing breast cancer. Here, we assessed cellular metabolic reprogramming of mammary carcinoma cells in response to increased collagen matrix density using an in vitro 3D model. Our initial observations demonstrated changes in functional metabolism in both normal mammary epithelial cells and mammary carcinoma cells in response to changes in matrix density. Further, mammary carcinoma cells grown in high density collagen matrices displayed decreased oxygen consumption and glucose metabolism via the tricarboxylic acid (TCA cycle compared to cells cultured in low density matrices. Despite decreased glucose entry into the TCA cycle, levels of glucose uptake, cell viability, and ROS were not different between high and low density matrices. Interestingly, under high density conditions the contribution of glutamine as a fuel source to drive the TCA cycle was significantly enhanced. These alterations in functional metabolism mirrored significant changes in the expression of metabolic genes involved in glycolysis, oxidative phosphorylation, and the serine synthesis pathway. This study highlights the broad importance of the collagen microenvironment to cellular expression profiles, and shows that changes in density of the collagen microenvironment can modulate metabolic shifts of cancer cells.

  1. Estimation of current density distribution of PAFC by analysis of cell exhaust gas

    Energy Technology Data Exchange (ETDEWEB)

    Kato, S.; Seya, A. [Fuji Electric Co., Ltd., Ichihara-shi (Japan); Asano, A. [Fuji Electric Corporate, Ltd., Yokosuka-shi (Japan)

    1996-12-31

    To estimate distributions of Current densities, voltages, gas concentrations, etc., in phosphoric acid fuel cell (PAFC) stacks, is very important for getting fuel cells with higher quality. In this work, we leave developed a numerical simulation tool to map out the distribution in a PAFC stack. And especially to Study Current density distribution in the reaction area of the cell, we analyzed gas composition in several positions inside a gas outlet manifold of the PAFC stack. Comparing these measured data with calculated data, the current density distribution in a cell plane calculated by the simulation, was certified.

  2. High-performance all-polymer solar cells via side-chain engineering of the polymer acceptor: the importance of the polymer packing structure and the nanoscale blend morphology.

    Science.gov (United States)

    Lee, Changyeon; Kang, Hyunbum; Lee, Wonho; Kim, Taesu; Kim, Ki-Hyun; Woo, Han Young; Wang, Cheng; Kim, Bumjoon J

    2015-04-17

    The effectiveness of side-chain engineering is demonstrated to produce highly efficient all-polymer solar cells (efficiency of 5.96%) using a series of naphthalene diimide-based polymer acceptors with controlled side chains. The dramatic changes in the polymer packing, blend morphology, and electron mobility of all-polymer solar cells elucidate clear trends in the photovoltaic performances. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. RelE-mediated dormancy is enhanced at high cell density in Escherichia coli.

    Science.gov (United States)

    Tashiro, Yosuke; Kawata, Koji; Taniuchi, Asami; Kakinuma, Kenji; May, Thithiwat; Okabe, Satoshi

    2012-03-01

    Bacteria show remarkable adaptability under several stressful conditions by shifting themselves into a dormant state. Less is known, however, about the mechanism underlying the cell transition to dormancy. Here, we report that the transition to dormant states is mediated by one of the major toxin-antitoxin systems, RelEB, in a cell density-dependent manner in Escherichia coli K-12 MG1655. We constructed a strain, IKA121, which expresses the toxin RelE in the presence of rhamnose and lacks chromosomal relBE and rhaBAD. With this strain, we demonstrated that RelE-mediated dormancy is enhanced at high cell densities compared to that at low cell densities. The initiation of expression of the antitoxin RelB from a plasmid, pCA24N, reversed RelE-mediated dormancy in bacterial cultures. The activation of RelE increased the appearance of persister cells against β-lactams, quinolones, and aminoglycosides, and more persister cells appeared at high cell densities than at low cell densities. Further analysis indicated that amino acid starvation and an uncharacterized extracellular heat-labile substance promote RelE-mediated dormancy. This is a first report on the induction of RelE-mediated dormancy by high cell density. This work establishes a population-based dormancy mechanism to help explain E. coli survival in stressful environments.

  4. Physiological responses to acid stress by Saccharomyces cerevisiae when applying high initial cell density

    Science.gov (United States)

    2016-01-01

    High initial cell density is used to increase volumetric productivity and shorten production time in lignocellulosic hydrolysate fermentation. Comparison of physiological parameters in high initial cell density cultivation of Saccharomyces cerevisiae in the presence of acetic, formic, levulinic and cinnamic acids demonstrated general and acid-specific responses of cells. All the acids studied impaired growth and inhibited glycolytic flux, and caused oxidative stress and accumulation of trehalose. However, trehalose may play a role other than protecting yeast cells from acid-induced oxidative stress. Unlike the other acids, cinnamic acid did not cause depletion of cellular ATP, but abolished the growth of yeast on ethanol. Compared with low initial cell density, increasing initial cell density reduced the lag phase and improved the bioconversion yield of cinnamic acid during acid adaptation. In addition, yeast cells were able to grow at elevated concentrations of acid, probable due to the increase in phenotypic cell-to-cell heterogeneity in large inoculum size. Furthermore, the specific growth rate and the specific rates of glucose consumption and metabolite production were significantly lower than at low initial cell density, which was a result of the accumulation of a large fraction of cells that persisted in a viable but non-proliferating state. PMID:27620460

  5. Cells determine cell density using a small protein bound to a unique tissue-specific phospholipid

    Directory of Open Access Journals (Sweden)

    Christopher J. Petzold

    2013-10-01

    Full Text Available Cell density is the critical parameter controlling tendon morphogenesis. Knowing its neighbors allows a cell to regulate correctly its proliferation and collagen production. A missing link to understanding this process is a molecular description of the sensing mechanism. Previously, this mechanism was shown in cell culture to rely on a diffusible factor (SNZR [sensor] with an affinity for the cell layer. This led to purifying conditioned medium over 4 columns and analyzing the final column fractions for band intensity on SDS gels versus biological activity – a 16 kD band strongly correlated between assays. N-terminal sequencing – EPLAVVDL – identified a large gene (424 AA, extremely conserved between chicken and human. In this paper we probe whether this is the correct gene. Can the predicted large protein be cleaved to a smaller protein? EPLAVVDL occurs towards the C-terminus and cleavage would create a small 94 AA protein. This protein would run at ∼10 kD, so what modifications or cofactor binding accounts for its running at 16 kD on SDS gels? This protein has no prominent hydrophobic regions, so can it be secreted? To validate its role, the chicken cDNA for this gene was tagged with myc and his and transfected into a human osteosarcoma cell line (U2OS. U2OS cells expressed the gene but not passively: differentiating into structures resembling spongy bone and expressing alkaline phosphatase, an early bone marker. Intracellularly, two bands were observed by Western blotting: the full length protein and a smaller form (26 kD. Outside the cell, a small band (28 kD was detected, although it was 40% larger than expected, as well as multiple larger bands. These larger forms could be converted to the predicted smaller protein (94 AA + tags by changing salt concentrations and ultrafiltering – releasing a cofactor to the filtrate while leaving a protein factor in the retentate. Using specific degradative enzymes and mass spectrometry, the

  6. Cell Growth on ("Janus") Density Gradients of Bifunctional Zeolite L Crystals.

    Science.gov (United States)

    Kehr, Nermin Seda; Motealleh, Andisheh; Schäfer, Andreas H

    2016-12-28

    Nanoparticle density gradients on surfaces have attracted interest as two-dimensional material surfaces that can mimic the complex nano-/microstructure of the native extracellular matrix, including its chemical and physical gradients, and can therefore be used to systematically study cell-material interactions. In this respect, we report the preparation of density gradients made of bifunctional zeolite L crystals on glass surfaces and the effects of the density gradient and biopolymer functionalization of zeolite L crystals on cell adhesion. We also describe how we created "Janus" density gradient surfaces by gradually depositing two different types of zeolite L crystals that were functionalized and loaded with different chemical groups and guest molecules onto the two distinct sides of the same glass substrate. Our results show that more cells adhered on the density gradient of biopolymer-coated zeolites than on uncoated ones. The number of adhered cells increased up to a certain surface coverage of the glass by the zeolite L crystals, but then it decreased beyond the zeolite density at which a higher surface coverage decreased fibroblast cell adhesion and spreading. Additionally, cell experiments showed that cells gradually internalized the guest-molecule-loaded zeolite L crystals from the underlying density gradient containing bifunctional zeolite L crystals.

  7. The density of the cell sap and endoplasm of Nitellopsis and Chara

    Science.gov (United States)

    Wayne, R.; Staves, M. P.

    1991-01-01

    We measured the densities of the cell sap, endoplasm and cell wall of Nitellopsis obtusa and Chara corallina using interference microscopy, refractometry, immersion refractometry, equilibrium sedimentation and chemical microanalysis techniques. These values are important for the determination of many rheological properties of the cytoplasm as well as for understanding buoyancy regulation, dispersal mechanisms and how cells respond to gravity. The average densities of the cell sap, endoplasm and cell wall are 1,006.9, 1,016.7 and 1,371 kg m-3 for Nitellopsis and 1,005.0, 1,013.9, and 1,355.3 kg m-3 for Chara.

  8. Biological Function and Mechanism of Bone Marrow Mesenchymal Stem Cells-packed Poly (3,4-ethylenedioxythiophene) (PEDOT) Scaffolds for Peripheral Nerve Injury: The Involvement of miR-21-Notch Signaling Pathway.

    Science.gov (United States)

    Wu, Wenliang; Zhang, Shijun; Chen, Yunzhen; Liu, Haichun

    2017-01-01

    Ununited peripheral nerves represent attractive site for connectivity with neuroprostheses because their predictable internal topography allows precise sorting of motor and sensory signals. Also transplantation of bone marrow mesenchymal stem cells (BMSCs) is increasingly recognized as an effective method of restore the peripheral nervous system injury due to its neuron-directed differentiation potential. This study was to evaluate the in vivo performance of BMSCs-packed Poly(3,4-ethylenedioxythiophene) (PEDOT) scaffolds across a critical nerve conduction gap and examine the potential mechanism by which BMSCs-packed PEDOT scaffolds mediate peripheral nerve regeneration in rat model of recurrent laryngeal nerve (RLN) deletion. In this study, rat models of 8 mm-RLN deletion were randomly divided into three groups and respectively received transplantation of autologous nerve or PEDOT scaffolds or BMSCspacked PEDOT scaffolds. After transplantation, neurological function was assessed by laryngeal electromyography. BMSCs-directed neuron differentiation was induced and confirmed by the upregulation of 6 nerve cell markers. Expression level of miRs, Notch signals and 6 nerve cell markers in nerve grafts or cells were determined by quantitative real-time PCR or western blot analysis. The results showed that BMSCs-packed PEDOT scaffolds transplantation significantly improved neurological function compared with PEDOT scaffolds alone. Regenerative nerve of BMSCs-packed PEDOT scaffolds showed higher expression level of miR-21 and Notch signals (Hes-1 and Notch intracellular domain (NICD)) than PEDOT alone. We found that the expression levels of miR-21, Hes-1 and NICD are increased with timecourse of neuron-directed differentiation stimulating of BMSCs. Meanwhile, both miR-21 overexpression and Notch pathway activation promote the expression of 6 nerve cell markers in BMSCs-directed neuron, whereas the inactivation of Notch pathway abrogates miR-21-inudced upregulation of 6

  9. A Crossed Pack-to-Cell Equalizer Based on Quasi-Resonant LC Converter with Adaptive Fuzzy Logic Equalization Control for Series-connected Lithium-Ion Battery Strings

    DEFF Research Database (Denmark)

    Shang, Yunlong; Zhang, Chenghui; Cui, Naxin

    2015-01-01

    and electromagnetic interference (EMI). Furthermore, an adaptive fuzzy logic control (AFLC) algorithm is employed to online regulate the equalization period according to the voltage difference between cells and the cell voltage, not only greatly abbreviating the balancing time but also effectively preventing over......The equalization speed, efficiency, and control are the key issues of battery equalization. This paper proposes a crossed pack-to-cell equalizer based on quasi-resonant LC converter (QRLCC). The battery string is divided into M modules, and each module consists of N series-connected cells...

  10. Cell engineering of Escherichia coli allows high cell density accumulation without fed-batch process control.

    Science.gov (United States)

    Bäcklund, Emma; Markland, Katrin; Larsson, Gen

    2008-01-01

    A set of mutations in the phosphoenolpyruvate:carbohydrate phosphotransferase system (PTS) was used to create Escherichia coli strains with a reduced uptake rate of glucose. This allows a growth restriction, which is controlled on cellular rather than reactor level, which is typical of the fed-batch cultivation concept. Batch growth of the engineered strains resulted in cell accumulation profiles corresponding to a growth rate of 0.78, 0.38 and 0.25 h(-1), respectively. The performance of the mutants in batch cultivation was compared to fed-batch cultivation of the wild type cell using restricted glucose feed to arrive at the corresponding growth profiles. Results show that the acetate production, oxygen consumption and product formation were similar, when a recombinant product was induced from the lacUV5 promoter. Ten times more cells could be produced in batch cultivation using the mutants without the growth detrimental production of acetic acid. This allows high cell density production without the establishment of elaborate fed-batch control equipment. The technique is suggested as a versatile tool in high throughput multiparallel protein production but also for increasing the number of experiments performed during process development while keeping conditions similar to the large-scale fed-batch performance.

  11. Solving the Granular Inverse Packing Problem with Artificial Evolution

    Science.gov (United States)

    Miskin, Marc; Jaeger, Heinrich

    2014-03-01

    If a collection of identical particles is poured into a container, it is obvious that different shapes will fill to different densities. But what is the shape that fills a container as close as possible to a pre-specified, desired density? We demonstrate a solution to this inverse-packing problem by framing it in the context of artificial evolution. By representing shapes as bonded spheres, we show how particles may be mutated, simulated, and selected to produce particularly dense or loose packing aggregates, both with and without friction. Moreover, we show how motifs emerge linking these shapes together. The result is a set of design rules that function as an effective solution to the inverse packing problem for given packing procedures and boundary conditions. Finally, we show that these results may be verified by experiments on 3d printed prototypes used to make packings in the real world.

  12. Evaluation of the effect of routine packed red blood cell transfusion in anemic cervix cancer patients treated with radical radiotherapy

    International Nuclear Information System (INIS)

    Kapp, Karin S.; Poschauko, Johann; Geyer, Edith; Berghold, Andrea; Oechs, Astrid C.; Petru, Edgar; Lahousen, Manfred; Kapp, Daniel S.

    2002-01-01

    Purpose: It is well established that anemia predicts diminished radiocurability in cervix cancer. However, the therapeutic benefit of measures to correct the anemia remains controversial. The objective of this study was to determine the impact of routine transfusion in patients with hemoglobin level (hb-l) ≤11 g/dl. Methods and Materials: Since 1985, it has been departmental policy to attempt to correct hb-l ≤11 g/dl before and/or during radiotherapy by red blood cell transfusion (RBCT) in patients undergoing radical radiotherapy for primary cervix cancer. To assess the benefit of RBCT, the charts of 204 patients (FIGO: IB-IV) treated until 1997 were reviewed. Parameters analyzed for their impact on disease-specific survival (DSS), pelvic control (PC), and metastases-free survival (MFS) included pretreatment hb-l, treatment hb-l, stage, tumor size, and lymph node status. To determine any differences in outcome according to type of anemia, a separate analysis was performed, grouping patients by cause of anemia (tumor vs. other medical illness related). Results: Each of the parameters tested was significantly correlated with the end points studied in univariate analysis. Patients whose hb-l were corrected (18.5%) had an outcome that did not differ significantly from that of nontransfused patients, whereas DSS, PC, and MFS (all: p<0.001) were significantly decreased in nonresponders to RBCT. Subgroup analysis showed no impact of hb-l in patients with other medical illness-related anemia (n=12). In multivariate analysis treatment, but not pretreatment, hb-l remained predictive for DSS, PC, and MFS. Persistent anemia was associated with a significantly increased risk of death (relative risk: 2.1) and pelvic failure (relative risk: 2.4) compared with nontransfused patients. If only patients with tumor anemia were considered, the respective risks increased (2.7; 3.6). None of the patients with other causes of anemia recurred, whether or not their hb-l was maintained

  13. Effect of packing fraction variations on reactivity in pebble-bed reactor

    International Nuclear Information System (INIS)

    Snoj, L.; Ravnik, M.

    2004-01-01

    The pebble-bed reactor (PBR) core consists of large number of randomly packed spherical fuel elements. The effect of fuel element packing density variations on multiplication factor in a typical PBR is studied using WIMS code. It is observed that at normal conditions the k-eff increases with packing fraction. Effects of secondary coolant ingress (water or molten lead) in the core at accidental conditions are studied at various packing densities. The effect of water ingress on reactivity depends strongly on water density and packing fraction and is prevailingly positive, while the lead ingress reduces multiplication factor regardless of lead effective density and packing fraction. Both effects are stronger at lower packing fractions. (author)

  14. 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

  15. Endothelial cell density after deep anterior lamellar keratoplasty (Melles technique)

    NARCIS (Netherlands)

    van Dooren, Bart T. H.; Mulder, Paul G. H.; Nieuwendaal, Carla P.; Beekhuis, W. Houdijn; Melles, Gerrit R. J.

    2004-01-01

    To measure the recipient endothelial cell loss after the Melles technique for deep anterior lamellar keratoplasty. In 21 eyes of 21 patients, a deep anterior lamellar keratoplasty procedure was performed. Before surgery and at 6, 12, and 24 months after surgery, specular microscopy was performed to

  16. Substrate compliance versus ligand density in cell on gel responses

    Czech Academy of Sciences Publication Activity Database

    Engler, A.; Bačáková, Lucie; Newman, C.; Hategan, A.; Griffin, M.; Discher, D.

    2004-01-01

    Roč. 86, č. 1 (2004), s. 617-628 ISSN 0006-3495 Grant - others:GA-(US) National Science Foundation; GA-(US) National Institutes of Health; GA-(US) Muscular Dystrophy Association Institutional research plan: CEZ:AV0Z5011922 Keywords : material stiffness * cell spreading * focal adhesions Subject RIV: BO - Biophysics Impact factor: 4.585, year: 2004

  17. Models for high cell density bioreactors must consider biomass volume fraction: Cell recycle example.

    Science.gov (United States)

    Monbouquette, H G

    1987-06-01

    Intrinsic models, which take into account biomass volume fraction, must be formulated for adequate simulation of high-biomass-density fermentations with cell recycle. Through comparison of corresponding intrinsic and non-intrinsic models in dimensionless form, constraints for non-intrinsic model usage in terms of biokinetic and fermenter operating parameters can be identified a priori. Analysis of a simple product-inhibition model indicates that the non-intrinsic approach is suitable only when the attainable biomass volume fraction in the fermentation broth is less than about 0.10. Inappropriate application of a non-intrinsic model can lead to gross errors in calculated substrate and product concentrations, substrate conversion, and volumetric productivity.

  18. Models for high cell density bioreactors must consider biomass volume fraction: cell recycle example

    Energy Technology Data Exchange (ETDEWEB)

    Monbouquette, H.G.

    1987-06-01

    Intrinsic models, which take into account biomass volume fraction, must be formulated for adequate simulation of high-biomass-density fermentations with cell recycle. Through comparison of corresponding intrinsic and non-intrinsic models in dimensionless form, constraints for non-intrinsic model usage in terms of biokinetic and fermenter operating parameters can be identified a priori. Analysis of a simple product-inhibition model indicates that the non-intrinsic approach is suitable only when the attainable biomass volume fraction in the fermentation broth is less than about 0.10. Inappropriate application of a non-intrinsic model can lead to gross errors in calculated substrate and product concentrations, substrate conversion, and volumetric productivity. (Refs. 14).

  19. Using crosslinkable diacetylene phospholipids to construct two-dimensional packed beds in supported lipid bilayer separation platforms

    Directory of Open Access Journals (Sweden)

    Shu-Kai Hu, Sheng-Wen Hsiao, Hsun-Yen Mao, Ya-Ming Chen, Yung Chang and Ling Chao

    2013-01-01

    Full Text Available Separating and purifying cell membrane-associated biomolecules has been a challenge owing to their amphiphilic property. Taking these species out of their native lipid membrane environment usually results in biomolecule degradation. One of the new directions is to use supported lipid bilayer (SLB platforms to separate the membrane species while they are protected in their native environment. Here we used a type of crosslinkable diacetylene phospholipids, diynePC (1,2-bis(10,12-tricosadiynoyl-sn-glycero-3-phosphocholine, as a packed material to create a 'two-dimensional (2D packed bed' in a SLB platform. After the diynePC SLB is exposed to UV light, some of the diynePC lipids in the SLB can crosslink and the non-crosslinked monomer lipids can be washed away, leaving a 2D porous solid matrix. We incorporated the lipid vesicle deposition method with a microfluidic device to pattern the location of the packed-bed region and the feed region with species to be separated in a SLB platform. Our atomic force microscopy result shows that the nano-scaled structure density of the '2D packed bed' can be tuned by the UV dose applied to the diynePC membrane. When the model membrane biomolecules were forced to transport through the packed-bed region, their concentration front velocities were found to decrease linearly with the UV dose, indicating the successful creation of packed obstacles in these 2D lipid membrane separation platforms.

  20. Conjunctival Goblet Cell Density Following Cataract Surgery With Diclofenac Versus Diclofenac and Rebamipide: A Randomized Trial.

    Science.gov (United States)

    Kato, Kumiko; Miyake, Kensaku; Kondo, Nagako; Asano, Sayaka; Takeda, Junko; Takahashi, Akiko; Takashima, Yuko; Kondo, Mineo

    2017-09-01

    To determine the effects of topical diclofenac or betamethasone with concomitant application of topical rebamipide on the conjunctival goblet cell density in eyes after cataract surgery. Randomized clinical trial. Eighty patients who were scheduled for cataract surgery. Patients were randomized into 4 groups according to the postoperative topical drugs to be given; Group A, diclofenac alone; Group B, diclofenac and rebamipide; Group C, betamethasone alone; and Group D, betamethasone and rebamipide. Impression cytology was performed before and at 1 month after the surgery, and the mean density of goblet cells was determined. The mean (± SD) density of goblet cells before the surgery in Group A was 257.0 ± 188.7 cells/mm 2 , and it decreased significantly to 86.5 ± 76.7 cells/mm 2 at 1 month after the surgery (P = .002). In Group B, the goblet cell density was not statistically different between before (238.5 ± 116.6 cells/mm 2 ) and at 1 month after the surgery (211.3 ± 184.4 cells/mm 2 , P = .55). In Groups C and D, the mean density of goblet cells was decreased at 1 month after the surgery, but the decreases were not significant (P = .11 and P = .52, respectively). After cataract surgery with postoperative topical diclofenac, the conjunctival goblet cell density was significantly reduced, and this reduction was blocked by the concomitant use of topical rebamipide. These results suggest that the concomitant use of topical rebamipide with nonsteroidal anti-inflammatory drugs is beneficial, especially in cases with postoperative dry eyes. Copyright © 2017 The Author(s). Published by Elsevier Inc. All rights reserved.

  1. Packing frustration in dense confined fluids.

    Science.gov (United States)

    Nygård, Kim; Sarman, Sten; Kjellander, Roland

    2014-09-07

    Packing frustration for confined fluids, i.e., the incompatibility between the preferred packing of the fluid particles and the packing constraints imposed by the confining surfaces, is studied for a dense hard-sphere fluid confined between planar hard surfaces at short separations. The detailed mechanism for the frustration is investigated via an analysis of the anisotropic pair distributions of the confined fluid, as obtained from integral equation theory for inhomogeneous fluids at pair correlation level within the anisotropic Percus-Yevick approximation. By examining the mean forces that arise from interparticle collisions around the periphery of each particle in the slit, we calculate the principal components of the mean force for the density profile--each component being the sum of collisional forces on a particle's hemisphere facing either surface. The variations of these components with the slit width give rise to rather intricate changes in the layer structure between the surfaces, but, as shown in this paper, the basis of these variations can be easily understood qualitatively and often also semi-quantitatively. It is found that the ordering of the fluid is in essence governed locally by the packing constraints at each single solid-fluid interface. A simple superposition of forces due to the presence of each surface gives surprisingly good estimates of the density profiles, but there remain nontrivial confinement effects that cannot be explained by superposition, most notably the magnitude of the excess adsorption of particles in the slit relative to bulk.

  2. Heuristics for Multidimensional Packing Problems

    DEFF Research Database (Denmark)

    Egeblad, Jens

    costs significantly. For packing problems in general are given a set of items and one of more containers. The items must be placed within the container such that some objective is optimized and the items do not overlap. Items and container may be rectangular or irregular (e.g. polygons and polyhedra...... methods. Two important problem variants are the knapsack packing problem and the strip-packing problem. In the knapsack packing problem, each item is given a profit value, and the problem asks for the subset with maximal profit that can be placed within one container. The strip-packing problem asks...... for a minimum height container required for the items. The main contributions of the thesis are three new heuristics for strip-packing and knapsack packing problems where items are both rectangular and irregular. In the two first papers we describe a heuristic for the multidimensional strip-packing problem...

  3. LIF Density Measurement Calibration Using a Reference Cell

    Science.gov (United States)

    Domonkos, Matthew T.; Williams, George J., Jr.; Lyons, Valerie J. (Technical Monitor)

    2002-01-01

    Flight qualification of ion thrusters typically requires testing on the order of 10,000 hours. Extensive knowledge of wear mechanisms and rates is necessary to establish design confidence prior to long duration tests. Consequently, real-time erosion rate measurements offer the potential both to reduce development costs and to enhance knowledge of the dependency of component wear on operating conditions. Several previous studies have used laser induced fluorescence (LIF) to measure real-time, in situ erosion rates of ion thruster accelerator grids. Those studies provided only relative measurements of the erosion rate. In the present investigation, a molybdenum tube was resistively heated such that the evaporation rate yielded densities within the tube on the order of those expected from accelerator grid erosion. A pulsed UV laser was used to pump the ground state molybdenum at 345.64nm, and the non-resonant fluorescence at 550-nm was collected using a bandpass filter and a photomultiplier tube or intensified CCD array. The sensitivity of the fluorescence was evaluated to determine the limitations of the calibration technique. The suitability of the diagnostic calibration technique was assessed for application to ion engine erosion rate measurements.

  4. Multilevel SOT-MRAM Cell with a Novel Sensing Scheme for High-Density Memory Applications

    DEFF Research Database (Denmark)

    Zeinali, Behzad; Esmaeili, Mahsa; Madsen, Jens Kargaard

    2017-01-01

    in high-density memory application. To deal with this obstacle, we propose a multilevel cell which stores two bits per memory cell. In addition, we propose a novel sensing scheme to read out the stored data in the multilevel SOT-MRAM cell. Our simulation results show that the proposed cell can achieve 3X......This paper presents a multilevel spin-orbit torque magnetic random access memory (SOT-MRAM). The conventional SOT-MRAMs enables a reliable and energy efficient write operation. However, these cells require two access transistors per cell, hence the efficiency of the SOTMRAMs can be questioned...

  5. Endothelial cell perturbation and low-density lipoprotein. Quantitative autoradiography

    International Nuclear Information System (INIS)

    Morrel, E.M.; Holland, J.A.; Pritchard, K.A.; Colton, C.K.; Stemerman, M.B.

    1987-01-01

    The focal entry and accumulation of LDL within the arterial wall of the normal animal may represent an early stage in the development of the atherosclerotic plaque. Concentrations of LDL 10 to 100 times normal medial concentrations might be difficult to clear from the arterial wall, permitting accumulation of lipid. Elevated LDL concentrations, in proximity to smooth muscle cells, appear to stimulate SMC proliferation. High LDL concentrations might also enhance mononuclear cell adhesion to endothelium. Since LDL has a high affinity for heparin and heparin for growth factors, LDL accumulation may be a mechanism for the concentration of such materials in the intima. The observation of markedly enhanced macromolecular permeability foci could be related to several potential mechanisms of initiation of atherosclerosis. This observation is of particular note when the focal occurrence of atherosclerosis is considered. Although atherosclerosis is seen as a generalized thickening of the intima, it is the focal narrowing of the lumen that is often responsible for the stenosis which produces symptoms such as angina or myocardial infarction

  6. Argo packing friction research update

    International Nuclear Information System (INIS)

    VanTassell, D.M.

    1994-01-01

    This paper focuses on the issue of valve packing friction and its affect on the operability of motor- and air-operated valves (MOVs and AOVs). At this time, most nuclear power plants are required to perform postmaintenance testing following a packing adjustment or replacement. In many cases, the friction generated by the packing does not impact the operability window of a valve. However, to date there has not been a concerted effort to substantiate this claim. To quantify the effects of packing friction, it has become necessary to develop a formula to predict the friction effects accurately. This formula provides a much more accurate method of predicting packing friction than previously used factors based strictly on stem diameter. Over the past 5 years, Argo Packing Company has been developing and testing improved graphite packing systems at research facilities, such as AECL Chalk River and Wyle Laboratories. Much of this testing has centered around reducing and predicting friction that is related to packing. In addition, diagnostic testing for Generic Letter 89-10 MOVs and AOVs has created a significant data base. In July 1992 Argo asked several utilities to provide running load data that could be used to quantify packing friction repeatability and predictability. This technical paper provides the basis to predict packing friction, which will improve calculations for thrust requirements for Generic Leter 89-10 and future AOV programs. In addition, having an accurate packing friction formula will improve packing performance when low running loads are identified that would indicate insufficient sealing force

  7. Insulin-like growth factor-II receptors in cultured rat hepatocytes: regulation by cell density

    International Nuclear Information System (INIS)

    Scott, C.D.; Baxter, R.C.

    1987-01-01

    Insulin-like growth factor-II (IGF-II) receptors in primary cultures of adult rat hepatocytes were characterized and their regulation by cell density examined. In hepatocytes cultured at 5 X 10(5) cells per 3.8 cm2 plate [ 125 I]IGF-II bound to specific, high affinity receptors (Ka = 4.4 +/- 0.5 X 10(9) l/mol). Less than 1% cross-reactivity by IGF-I and no cross-reactivity by insulin were observed. IGF-II binding increased when cells were permeabilized with 0.01% digitonin, suggesting the presence of an intracellular receptor pool. Determined by Scatchard analysis and by polyacrylamide gel electrophoresis after affinity labeling, the higher binding was due solely to an increase in binding sites present on 220 kDa type II IGF receptors. In hepatocytes cultured at low densities, the number of cell surface receptors increased markedly, from 10-20,000 receptors per cell at a culture density of 6 X 10(5) cells/well to 70-80,000 receptors per cell at 0.38 X 10(5) cells/well. The increase was not due simply to the exposure of receptors from the intracellular pool, as a density-related increase in receptors was also seen in cells permeabilized with digitonin. There was no evidence that IGF binding proteins, either secreted by hepatocytes or present in fetal calf serum, had any effect on the measurement of receptor concentration or affinity. We conclude that rat hepatocytes in primary culture contain specific IGF-II receptors and that both cell surface and intracellular receptors are regulated by cell density

  8. The Six Pack Model

    DEFF Research Database (Denmark)

    Andersen, Henrik; Ritter, Thomas

    Ever seen a growth strategies fail because it was not connect ed to the firm’s customer base? Or a customer relationship strategy falters just because it was the wrong thing to do with that given customer? This article presents the six pack model, a tool that makes growth profitable and predictable....... Not all customers can and should grow – thus a firm needs to classify its customers in order to implement the right customer strategy....

  9. Effect of Cell Seeding Density and Inflammatory Cytokines on Adipose Tissue-Derived Stem Cells: an in Vitro Study.

    Science.gov (United States)

    Sukho, Panithi; Kirpensteijn, Jolle; Hesselink, Jan Willem; van Osch, Gerjo J V M; Verseijden, Femke; Bastiaansen-Jenniskens, Yvonne M

    2017-04-01

    Adipose tissue-derived stem cells (ASCs) are known to be able to promote repair of injured tissue via paracrine factors. However, the effect of cell density and inflammatory cytokines on the paracrine ability of ASCs remains largely unknown. To investigate these effects, ASCs were cultured in 8000 cells/cm 2 , 20,000 cells/cm 2 , 50,000 cells/cm 2 , and 400,000 cells/cm 2 with and without 10 or 20 ng/ml tumor necrosis factor alpha (TNFα) and 25 or 50 ng/ml interferon gamma (IFNγ). ASC-sheets formed at 400,000 cells/cm 2 after 48 h of culture. With increasing concentrations of TNFα and IFNγ, ASC-sheets with 400,000 cells/cm 2 had increased production of angiogenic factors Vascular Endothelial Growth Factor and Fibroblast Growth Factor and decreased expression of pro-inflammatory genes TNFA and Prostaglandin Synthase 2 (PTGS2) compared to lower density ASCs. Moreover, the conditioned medium of ASC-sheets with 400,000 cells/cm 2 stimulated with the low concentration of TNFα and IFNγ enhanced endothelial cell proliferation and fibroblast migration. These results suggest that a high cell density enhances ASC paracrine function might beneficial for wound repair, especially in pro-inflammatory conditions.

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

    DEFF Research Database (Denmark)

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

    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......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...

  11. Three Dimensional Thermal Modeling of Li-Ion Battery Pack Based on Multiphysics and Calorimetric Measurement

    DEFF Research Database (Denmark)

    Khan, Mohammad Rezwan; Kær, Søren Knudsen

    2016-01-01

    . Inside the battery cells in the pack a lumped value of heat generation (HG), that works as a volumetric heat source, is used. The measured HG stems from the cell level isothermal calorimeter experiment. The batteries inside the pack stay in the same initial thermal state in the simulation case. The pack...

  12. A Density-Driven Method for the Placement of Biological Cells Over Two-Dimensional Manifolds

    Science.gov (United States)

    Rougier, Nicolas P.

    2018-01-01

    We introduce a graphical method originating from the computer graphics domain that is used for the arbitrary placement of cells over a two-dimensional manifold. Using a bitmap image whose luminance provides cell density, this method guarantees a discrete distribution of the positions of the cells respecting the local density. This method scales to any number of cells, allows one to specify arbitrary enclosing shapes and provides a scalable and versatile alternative to the more classical assumption of a uniform spatial distribution. The method is illustrated on a discrete homogeneous neural field, on the distribution of cones and rods in the retina and on the neural density of a flattened piece of cortex.

  13. A Density-Driven Method for the Placement of Biological Cells Over Two-Dimensional Manifolds

    Directory of Open Access Journals (Sweden)

    Nicolas P. Rougier

    2018-03-01

    Full Text Available We introduce a graphical method originating from the computer graphics domain that is used for the arbitrary placement of cells over a two-dimensional manifold. Using a bitmap image whose luminance provides cell density, this method guarantees a discrete distribution of the positions of the cells respecting the local density. This method scales to any number of cells, allows one to specify arbitrary enclosing shapes and provides a scalable and versatile alternative to the more classical assumption of a uniform spatial distribution. The method is illustrated on a discrete homogeneous neural field, on the distribution of cones and rods in the retina and on the neural density of a flattened piece of cortex.

  14. Effect of Cell Seeding Density and Inflammatory Cytokines on Adipose Tissue-Derived Stem Cells : an in Vitro Study

    NARCIS (Netherlands)

    Sukho, Panithi; Kirpensteijn, Jolle; Hesselink, Jan Willem; van Osch, Gerjo J V M; Verseijden, Femke; Bastiaansen-Jenniskens, Yvonne M

    Adipose tissue-derived stem cells (ASCs) are known to be able to promote repair of injured tissue via paracrine factors. However, the effect of cell density and inflammatory cytokines on the paracrine ability of ASCs remains largely unknown. To investigate these effects, ASCs were cultured in 8000

  15. Effect of Cell Seeding Density and Inflammatory Cytokines on Adipose Tissue-Derived Stem Cells: an in Vitro Study

    NARCIS (Netherlands)

    Sukho, P. (Panithi); J. Kirpensteijn (Jolle); Hesselink, J.W. (Jan Willem); G.J.V.M. van Osch (Gerjo); F. Verseijden (Femke); Y.M. Bastiaansen-Jenniskens (Yvonne)

    2017-01-01

    textabstractAdipose tissue-derived stem cells (ASCs) are known to be able to promote repair of injured tissue via paracrine factors. However, the effect of cell density and inflammatory cytokines on the paracrine ability of ASCs remains largely unknown. To investigate these effects, ASCs were

  16. Column-to-column packing variation of disposable pre-packed columns for protein chromatography.

    Science.gov (United States)

    Schweiger, Susanne; Hinterberger, Stephan; Jungbauer, Alois

    2017-12-08

    In the biopharmaceutical industry, pre-packed columns are the standard for process development, but they must be qualified before use in experimental studies to confirm the required performance of the packed bed. Column qualification is commonly done by pulse response experiments and depends highly on the experimental testing conditions. Additionally, the peak analysis method, the variation in the 3D packing structure of the bed, and the measurement precision of the workstation influence the outcome of qualification runs. While a full body of literature on these factors is available for HPLC columns, no comparable studies exist for preparative columns for protein chromatography. We quantified the influence of these parameters for commercially available pre-packed and self-packed columns of disposable and non-disposable design. Pulse response experiments were performed on 105 preparative chromatography columns with volumes of 0.2-20ml. The analyte acetone was studied at six different superficial velocities (30, 60, 100, 150, 250 and 500cm/h). The column-to-column packing variation between disposable pre-packed columns of different diameter-length combinations varied by 10-15%, which was acceptable for the intended use. The column-to-column variation cannot be explained by the packing density, but is interpreted as a difference in particle arrangement in the column. Since it was possible to determine differences in the column-to-column performance, we concluded that the columns were well-packed. The measurement precision of the chromatography workstation was independent of the column volume and was in a range of±0.01ml for the first peak moment and±0.007 ml 2 for the second moment. The measurement precision must be considered for small columns in the range of 2ml or less. The efficiency of disposable pre-packed columns was equal or better than that of self-packed columns. Copyright © 2017 The Author(s). Published by Elsevier B.V. All rights reserved.

  17. Modelling and simulation of double chamber microbial fuel cell. Cell voltage, power density and temperature variation with process parameters

    Energy Technology Data Exchange (ETDEWEB)

    Shankar, Ravi; Mondal, Prasenjit; Chand, Shri [Indian Institute of Technology Roorkee, Uttaranchal (India). Dept. of Chemical Engineering

    2013-11-01

    In the present paper steady state models of a double chamber glucose glutamic acid microbial fuel cell (GGA-MFC) under continuous operation have been developed and solved using Matlab 2007 software. The experimental data reported in a recent literature has been used for the validation of the models. The present models give prediction on the cell voltage and cell power density with 19-44% errors, which is less (up to 20%) than the errors on the prediction of cell voltage made in some recent literature for the same MFC where the effects of the difference in pH and ionic conductivity between anodic and cathodic solutions on cell voltage were not incorporated in model equations. It also describes the changes in anodic and cathodic chamber temperature due to the increase in substrate concentration and cell current density. Temperature profile across the membrane thickness has also been studied. (orig.)

  18. Microfluidic Adaptation of Density-Gradient Centrifugation for Isolation of Particles and Cells

    Directory of Open Access Journals (Sweden)

    Yuxi Sun

    2017-08-01

    Full Text Available Density-gradient centrifugation is a label-free approach that has been extensively used for cell separations. Though elegant, this process is time-consuming (>30 min, subjects cells to high levels of stress (>350 g and relies on user skill to enable fractionation of cells that layer as a narrow band between the density-gradient medium and platelet-rich plasma. We hypothesized that microfluidic adaptation of this technique could transform this process into a rapid fractionation approach where samples are separated in a continuous fashion while being exposed to lower levels of stress (<100 g for shorter durations of time (<3 min. To demonstrate proof-of-concept, we designed a microfluidic density-gradient centrifugation device and constructed a setup to introduce samples and medium like Ficoll in a continuous, pump-less fashion where cells and particles can be exposed to centrifugal force and separated via different outlets. Proof-of-concept studies using binary mixtures of low-density polystyrene beads (1.02 g/cm3 and high-density silicon dioxide beads (2.2 g/cm3 with Ficoll–Paque (1.06 g/cm3 show that separation is indeed feasible with >99% separation efficiency suggesting that this approach can be further adapted for separation of cells.

  19. Induction of xylanases by sugar cane bagasse at different cell densities of Cellulomonas flavigena.

    Science.gov (United States)

    Amaya-Delgado, L; Vega-Estrada, J; Flores-Cotera, L B; Dendooven, L; Hidalgo-Lara, M E; Montes-Horcasitas, M C

    2006-04-01

    The effect of cell density on xylanolytic activity and productivity of Cellulomonas flavigena was evaluated under two different culturing conditions: fed-batch culture with discontinuous feed of sugar cane bagasse (SCB; condition 1) and glycerol fed-batch culture followed by addition of SBC as xylanases inducer (condition 2). The enzymatic profile of xylanases was similar in both systems, regardless of the initial cell density at time of induction. However, the xylanolytic activity changed with initial cell density at the time of induction (condition 2). The maximum volumetric xylanase activity increased with increased initial cell density from 4 to 34 g l(-1) but decreased above this value. The largest total volumetric xylanase productivity under condition 2 (1.3 IU ml(-1) h(-1)) was significantly greater compared to condition 1 (maximum 0.6 IU ml(-1) h(-1)). Consequently, induction of xylanase activity by SCB after growing of C. flavigena on glycerol at intermediate cell density can be a feasible alternative to improve activity and productivity of xylanolytic enzymes.

  20. Control of Cell Attachment and Spreading on Poly(acrylamide) Brushes with Varied Grafting Density.

    Science.gov (United States)

    Lilge, Inga; Schönherr, Holger

    2016-01-26

    To achieve spatial control of fibroblast cell attachment and spreading on a biocompatible polymer coating, the effect of poly(acrylamide) (PAAm) brushes with varied grafting density was investigated. The synthesis of the brushes was performed by surface-initiated atom transfer radical polymerization (SI-ATRP). Gold substrates were modified with binary self-assembled monolayers (SAMs) of an initiator and 16-mercaptohexadecanoic acid (MHDA) as an "inert" thiol to initiate the ATRP of AAm. By using different mixtures for the binary SAMs, a series of polymer brushes with varied grafting densities were prepared. The fractional coverage of surface bound initiator was determined by grazing incidence Fourier transform infrared (FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), time-of-flight secondary ion mass spectrometry (ToF-SIMS), and contact angle measurements. A linear relationship between the Br/S ratio determined by XPS and ToF-SIMS versus the fraction of initiator on the surface determined by water contact angle measurements was observed. The varied initiation concentration on the gold substrates yielded PAAm brushes with different thicknesses, indicating a transition from mushroom to brush regimes with increasing grafting density. Thereby we achieved exquisite control of the degree of cell adhesion. Cell attachment experiments with NIH 3T3 fibroblast cells revealed cell spreading on PAAm brushes with low grafting densities (initiator fractional coverage <0.2) as well as a complete passivation by polymer brushes with higher grafting densities.

  1. Isolating peripheral lymphocytes by density gradient centrifugation and magnetic cell sorting.

    Science.gov (United States)

    Brosseron, Frederic; Marcus, Katrin; May, Caroline

    2015-01-01

    Combining density gradient centrifugation with magnetic cell sorting provides a powerful tool to isolate blood cells with high reproducibility, yield, and purity. It also allows for subsequent separation of multiple cell types, resulting in the possibility to analyze different purified fractions from one donor's sample. The centrifugation step divides whole blood into peripheral blood mononuclear cells (PBMC), erythrocytes, and platelet-rich plasma. In the following, lymphocyte subtypes can be consecutively isolated from the PBMC fraction. This chapter describes enrichment of erythrocytes, CD14-positive monocytes and CD3-positive T lymphocytes. Alternatively, other cell types can be targeted by using magnetic beads specific for the desired subpopulation.

  2. Multilayer DNA Origami Packed on Hexagonal and Hybrid Lattices

    DEFF Research Database (Denmark)

    Ke, Yonggang; Voigt, Niels Vinther; Shih, William M.

    2012-01-01

    “Scaffolded DNA origami” has been proven to be a powerful and efficient approach to construct two-dimensional or three-dimensional objects with great complexity. Multilayer DNA origami has been demonstrated with helices packing along either honeycomb-lattice geometry or square-lattice geometry....... Here we report successful folding of multilayer DNA origami with helices arranged on a close-packed hexagonal lattice. This arrangement yields a higher density of helical packing and therefore higher resolution of spatial addressing than has been shown previously. We also demonstrate hybrid multilayer...... DNA origami with honeycomb-lattice, square-lattice, and hexagonal-lattice packing of helices all in one design. The availability of hexagonal close-packing of helices extends our ability to build complex structures using DNA nanotechnology....

  3. Very high cell density perfusion of CHO cells anchored in a non-woven matrix-based bioreactor.

    Science.gov (United States)

    Zhang, Ye; Stobbe, Per; Silvander, Christian Orrego; Chotteau, Véronique

    2015-11-10

    Recombinant Chinese Hamster Ovary (CHO) cells producing IgG monoclonal antibody were cultivated in a novel perfusion culture system CellTank, integrating the bioreactor and the cell retention function. In this system, the cells were harbored in a non-woven polyester matrix perfused by the culture medium and immersed in a reservoir. Although adapted to suspension, the CHO cells stayed entrapped in the matrix. The cell-free medium was efficiently circulated from the reservoir into- and through the matrix by a centrifugal pump placed at the bottom of the bioreactor resulting in highly homogenous concentrations of the nutrients and metabolites in the whole system as confirmed by measurements from different sampling locations. A real-time biomass sensor using the dielectric properties of living cells was used to measure the cell density. The performances of the CellTank were studied in three perfusion runs. A very high cell density measured as 200 pF/cm (where 1 pF/cm is equivalent to 1 × 10(6)viable cells/mL) was achieved at a perfusion rate of 10 reactor volumes per day (RV/day) in the first run. In the second run, the effect of cell growth arrest by hypothermia at temperatures lowered gradually from 37 °C to 29 °C was studied during 13 days at cell densities above 100 pF/cm. Finally a production run was performed at high cell densities, where a temperature shift to 31 °C was applied at cell density 100 pF/cm during a production period of 14 days in minimized feeding conditions. The IgG concentrations were comparable in the matrix and in the harvest line in all the runs, indicating no retention of the product of interest. The cell specific productivity was comparable or higher than in Erlenmeyer flask batch culture. During the production run, the final harvested IgG production was 35 times higher in the CellTank compared to a repeated batch culture in the same vessel volume during the same time period. Copyright © 2015 The Authors. Published by Elsevier B.V. All

  4. To Pack or Not to Pack? A Randomized Trial of Vaginal Packing After Vaginal Reconstructive Surgery.

    Science.gov (United States)

    Westermann, Lauren B; Crisp, Catrina C; Oakley, Susan H; Mazloomdoost, Donna; Kleeman, Steven D; Benbouajili, Janine M; Ghodsi, Vivian; Pauls, Rachel N

    2016-01-01

    Placement of vaginal packing after pelvic reconstructive surgery is common; however, little evidence exists to support the practice. Furthermore, patients have reported discomfort from the packs. We describe pain and satisfaction in women treated with and without vaginal packing. This institutional review board-approved randomized-controlled trial enrolled patients undergoing vaginal hysterectomy with prolapse repairs. The primary outcome was visual analog scales (VASs) for pain on postoperative day 1. Allocation to "packing" ("P") or "no-packing" ("NP") arms occurred intraoperatively at the end of surgery. Visual analog scales regarding pain and satisfaction were completed early on postoperative day 1 before packing removal. Visual analog scale scores for pain, satisfaction, and bother attributable to packing were recorded before discharge. All packing and perineal pads were weighed to calculate a "postoperative vaginal blood loss." Perioperative data were collected from the hospital record. Our sample size estimation required 74 subjects. Ninety-three women were enrolled. After exclusions, 77 were randomized (P, 37; NP, 40). No differences were found in surgical information, hemoglobin levels, or narcotic use between groups. However, "postoperative vaginal blood loss" was greater in packed subjects (P discharge (P, 35.0 vs NP, 40.0; P = 0.43] were not significantly different between treatment arms. Likewise, VAS scores for satisfaction before removal of packing (P, 81.0 vs NP, 90.0; P = 0.08] and before discharge (P, 90.0 vs NP, 90.5; P = 0.60] were not significantly different. Packed patients noted lower nursing verbal pain scores (P = 0.04) and used less ketorolac (P = 0.01). Bother from packing was low overall. Although there was no difference based on VAS, women receiving vaginal packing had lower nursing documented pain and used less ketorolac than packed women. Vaginal packing may provide benefit and can remain part of the surgical practice.

  5. High-density polymer microarrays: identifying synthetic polymers that control human embryonic stem cell growth.

    Science.gov (United States)

    Hansen, Anne; Mjoseng, Heidi K; Zhang, Rong; Kalloudis, Michail; Koutsos, Vasileios; de Sousa, Paul A; Bradley, Mark

    2014-06-01

    The fabrication of high-density polymer microarray is described, allowing the simultaneous and efficient evaluation of more than 7000 different polymers in a single-cellular-based screen. These high-density polymer arrays are applied in the search for synthetic substrates for hESCs culture. Up-scaling of the identified hit polymers enables long-term cellular cultivation and promoted successful stem-cell maintenance. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Cell damage from radiation-induced bystander effects for different cell densities simulated by a mathematical model via cellular automata

    Energy Technology Data Exchange (ETDEWEB)

    Meireles, Sincler P. de; Santos, Adriano M.; Grynberg, Suely Epsztein, E-mail: spm@cdtn.b, E-mail: amsantos@cdtn.b, E-mail: seg@cdtn.b [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil); Nunes, Maria Eugenia S., E-mail: mariaeugenia@iceb.ufop.b [Universidade Federal de Ouro Preto (UFOP), MG (Brazil)

    2011-07-01

    During recent years, there has been a shift from an approach focused entirely on DNA as the main target of ionizing radiation to a vision that considers complex signaling pathways in cells and among cells within tissues. Several newly recognized responses were classified as the so-called non-target responses in which the biological effects are not directly related to the amount of energy deposited in the DNA of cells that were traversed by radiation. In 1992 the bystander effect was described referring to a series of responses such as death, chromosomal instability or other abnormalities that occur in non-irradiated cells that came into contact with irradiated cells or medium from irradiated cells. In this work, we have developed a mathematical model via cellular automata, to quantify cell death induced by the bystander effect. The model is based on experiments with irradiated cells conditioned medium which suggests that irradiated cells secrete molecules in the medium that are capable of damaging other cells. The computational model consists of two-dimensional cellular automata which is able to simulate the transmission of bystander signals via extrinsic route and via Gap junctions. The model has been validated by experimental results in the literature. The time evolution of the effect and the dose-response curves were obtained in good accordance to them. Simulations were conducted for different values of bystander and irradiated cell densities with constant dose. From this work, we have obtained a relationship between cell density and effect. (author)

  7. Cell damage from radiation-induced bystander effects for different cell densities simulated by a mathematical model via cellular automata

    International Nuclear Information System (INIS)

    Meireles, Sincler P. de; Santos, Adriano M.; Grynberg, Suely Epsztein; Nunes, Maria Eugenia S.

    2011-01-01

    During recent years, there has been a shift from an approach focused entirely on DNA as the main target of ionizing radiation to a vision that considers complex signaling pathways in cells and among cells within tissues. Several newly recognized responses were classified as the so-called non-target responses in which the biological effects are not directly related to the amount of energy deposited in the DNA of cells that were traversed by radiation. In 1992 the bystander effect was described referring to a series of responses such as death, chromosomal instability or other abnormalities that occur in non-irradiated cells that came into contact with irradiated cells or medium from irradiated cells. In this work, we have developed a mathematical model via cellular automata, to quantify cell death induced by the bystander effect. The model is based on experiments with irradiated cells conditioned medium which suggests that irradiated cells secrete molecules in the medium that are capable of damaging other cells. The computational model consists of two-dimensional cellular automata which is able to simulate the transmission of bystander signals via extrinsic route and via Gap junctions. The model has been validated by experimental results in the literature. The time evolution of the effect and the dose-response curves were obtained in good accordance to them. Simulations were conducted for different values of bystander and irradiated cell densities with constant dose. From this work, we have obtained a relationship between cell density and effect. (author)

  8. Changes in tumor oxygen tension during radiotherapy of uterine cervical cancer: relationships to changes in vascular density, cell density, and frequency of mitosis and apoptosis

    International Nuclear Information System (INIS)

    Lyng, Heidi; Sundfoer, Kolbein; Rofstad, Einar K.

    2000-01-01

    Purpose: Changes in oxygen tension (pO 2 ) during the early phase of fractionated radiotherapy were studied in 22 patients with uterine cervical cancer. The aims were to investigate (a) whether possible changes in pO 2 differed among and within tumors and (b) whether the changes could be attributed to changes in vascular density, cell density, and frequency of mitosis and apoptosis. Methods and Materials: The pO 2 was measured polarographically in four regions of the tumors before treatment and after 2 weeks of radiotherapy. The vascular density, cell density, and frequency of mitosis and apoptosis were determined from biopsies taken from the tumor regions after each pO 2 measurement. Results: The changes in pO 2 during therapy differed among the tumors and were correlated to pO 2 before treatment (p 2 and vice versa. The tumors with increased pO 2 (n = 10) had a large decrease in cell density and a significant increase in apoptotic frequency. In contrast, the tumors with decreased pO 2 (n = 10) had a smaller decrease in cell density (p = 0.014) and no significant increase in apoptotic frequency. Vascular density and mitotic frequency showed no change during therapy; however, vascular damage other than decreased vascular density was observed. Conclusion: These results indicate that the oxygenation of cervix tumors generally changes during the early phase of radiotherapy. The change depends on the balance between the factor leading to an increase and that leading to a decrease in oxygenation; i.e., decreased cell density and vascular damage, respectively. Increased apoptotic frequency may contribute to a large decrease in cell density and hence increased oxygenation during therapy

  9. Tetramethylpyrazine-mediated regulation of CXCR4 in retinoblastoma is sensitive to cell density.

    Science.gov (United States)

    Wu, Nandan; Xu, Lijun; Yang, Ying; Yu, Na; Zhang, Zhang; Chen, Pei; Zhang, Jing; Tang, Mingjun; Yuan, Meng; Ge, Jian; Yu, Keming; Zhuang, Jing

    2017-05-01

    Retinoblastoma is the most common ocular tumor in children, and it causes extensive damage. Current treatment options for retinoblastoma include surgery, chemotherapy, radiotherapy and cryotherapy. However, the majority of chemotherapy medicines cause complications and side effects that lead to severe impairment of patient health. Previous studies have reported that tetramethylpyrazine (TMP), which is an extract of the Chinese herbal medicine Chuanxiong, reduces the risk of multidrug resistance in chemotherapy and inhibits the proliferation and metastasis of various types of cancer cells. However, the underlying molecular mechanism of TMP in retinoblastoma remains unclear. The current study demonstrated that C-X-C chemokine receptor type 4 (CXCR4) was expressed in WERI‑Rb1 cells and in retinoblastoma. Using reverse transcription‑quantitative polymerase chain reaction and western blotting techniques, the current study demonstrated that TMP significantly downregulated the expression of CXCR4 in WERI‑Rb1 cells cultured at high density, whereas it had a minor effect in low‑density WERI‑Rb1 cells; additionally, this effect occurred in a time‑dependent manner. TMP inhibited the proliferation of WERI‑Rb1 cells as effectively as a CXCR4 antagonist, AMD3100, consistent with a role of CXCR4 in cancer development. Notably, TMP did not affect the cell cycle of cells cultured at low density (1x105 cells/ml), whereas it induced G1‑phase arrest in high‑density cells (7.5x105 cells/ml; Pretinoblastoma, and also provides novel insights into the mechanisms of the anti‑cancer and neuroprotective effects of this extract.

  10. Thermal conductivity of simple liquids: temperature and packing-fraction dependence.

    Science.gov (United States)

    Ohtori, Norikazu; Ishii, Yoshiki; Togawa, Yoshinori; Oono, Takuya; Takase, Keiichi

    2014-02-01

    The thermal conductivity of rare gases in liquid and dense fluid states has been evaluated using molecular dynamics simulation with the Lennard-Jones (LJ) potentials and the Green-Kubo (GK) formula. All the calculated thermal conductivities are in very good agreement with experimental results for a wide range of temperature and density. Special attention was paid to temperature and packing-fraction dependence which is nontrivial from dimensional analysis on the LJ potentials and the GK formula. First, the temperature dependence of T(1/4) was determined from the calculations at constant densities. Secondly, in order to obtain the dependence on packing fraction from that on number density separately, a scaling method of particle and/or cell size was introduced. The number density dependence of (N/V)(2/3) which is expected from the dimensional analysis of the GK formulas was confirmed and the packing-fraction dependence of η(3/2) was determined by using the scaling method. It turned out that the summarized functional form of m(-1/2)(N/V)(2/3)η(3/2)T(1/4) can well express both the calculated and experimental thermal conductivities for Ar, Kr, and Xe, where m is the atomic mass. The scaling method has also been applied to molten NaCl and KCl so that it has been found that the thermal conductivity has the packing-fraction dependence of η(2/3) which is much weaker than that of the simple LJ liquids.

  11. New bounds for multi-dimensional packing

    NARCIS (Netherlands)

    S. Seiden; R. van Stee (Rob)

    2001-01-01

    textabstractNew upper and lower bounds are presented for a multi-dimensional generalization of bin packing called box packing. Several variants of this problem, including bounded space box packing, square packing, variable sized box packing and resource augmented box packing are also studied. The

  12. LTE Micro-cell Deployment for High-Density Railway Areas

    DEFF Research Database (Denmark)

    Sniady, Aleksander; Kassab, Mohamed; Soler, José

    2014-01-01

    Long Term Evolution (LTE) is a serious candidate for the future releases of the European Rail Traffic Management System (ERTMS). LTE offers more capacity and supports new communication-based applications and services for railways. Nevertheless, even with this technology, the classical macro......-cell radio deployments reach overload, especially in high-density areas, such as major train stations. In this paper, an LTE micro-cell deployment is investigated in high-density railway areas. Copenhagen Main Station is considered as a realistic deployment study case, with a set of relevant railway...

  13. Heterogeneous packing and hydraulic stability of cube and cubipod armor units

    OpenAIRE

    GÓMEZ-MARTÍN, M. ESTHER; Medina, Josep R.

    2014-01-01

    This paper describes the heterogeneous packing (HEP) failure mode of breakwater armor. HEP reduces packing density in the armor layer near and above the mean water level and increases packing density below it. With HEP, armor units may move in the armor layer, although they are not actually extracted from it. Thus, when HEP occurs, armor-layer porosity is not constant, and measurements obtained with conventional methods may underestimate armor damage. In this paper, the Virtual Net method ...

  14. Complexity in Surfaces of Densest Packings for Families of Polyhedra

    Directory of Open Access Journals (Sweden)

    Elizabeth R. Chen

    2014-02-01

    Full Text Available Packings of hard polyhedra have been studied for centuries due to their mathematical aesthetic and more recently for their applications in fields such as nanoscience, granular and colloidal matter, and biology. In all these fields, particle shape is important for structure and properties, especially upon crowding. Here, we explore packing as a function of shape. By combining simulations and analytic calculations, we study three two-parameter families of hard polyhedra and report an extensive and systematic analysis of the densest known packings of more than 55 000 convex shapes. The three families have the symmetries of triangle groups (icosahedral, octahedral, tetrahedral and interpolate between various symmetric solids (Platonic, Archimedean, Catalan. We find optimal (maximum packing-density surfaces that reveal unexpected richness and complexity, containing as many as 132 different structures within a single family. Our results demonstrate the importance of thinking about shape not as a static property of an object, in the context of packings, but rather as but one point in a higher-dimensional shape space whose neighbors in that space may have identical or markedly different packings. Finally, we present and interpret our packing results in a consistent and generally applicable way by proposing a method to distinguish regions of packings and classify types of transitions between them.

  15. Model-based high cell density cultivation of Rhodospirillum rubrum under respiratory dark conditions.

    Science.gov (United States)

    Zeiger, Lisa; Grammel, Hartmut

    2010-03-01

    The potential of facultative photosynthetic bacteria as producers of photosynthetic pigments, vitamins, coenzymes and other valuable products has been recognized for decades. However, mass cultivation under photosynthetic conditions is generally inefficient due to the inevitable limitation of light supply when cell densities become very high. The previous development of a new cultivation process for maximal expression of photosynthetic genes under semi-aerobic dark conditions in common bioreactors offers a new perspective for utilizing the facultative photosynthetic bacterium Rhodospirillum rubrum for large-scale applications. Based on this cultivation system, the present study aimed in determining the maximal achievable cell density of R. rubrum in a bioreactor, thereby providing a major milestone on the way to industrial bioprocesses. As a starting point, we focus on aerobic growth due to higher growth rates and more facile process control under this condition, with the option to extend the process by an anaerobic production phase. Process design and optimization were supported by an unstructured computational process model, based on mixed-substrate kinetics. Key parameters for growth and process control were determined in shake-flask experiments or estimated by simulation studies. For fed-batch cultivation, a computer-controlled exponential feed algorithm in combination with a pH-stat element was implemented. As a result, a maximal cell density of 59 g cell dry weight (CDW) L(-1) was obtained, representing so far not attainable cell densities for photosynthetic bacteria. The applied exponential fed-batch methodology therefore enters a range which is commonly employed for industrial applications with microbial cells. The biochemical analysis of high cell density cultures revealed metabolic imbalances, such as the accumulation and excretion of tetrapyrrole intermediates of the bacteriochlorophyll biosynthetic pathway. (c) 2009 Wiley Periodicals, Inc.

  16. The effects of daily wear contact lenses on goblet cell density.

    Science.gov (United States)

    Connor, C G; Campbell, J B; Steel, S A; Burke, J H

    1994-11-01

    Some patients can wear contact lenses with a low tear breakup time while others with an identical tear breakup time cannot wear lenses. This suggests the current method of tear film assessment is inadequate at differentiating between these two types of patients. The study attempts to expand our knowledge of the tear film with special attention directed to a critical yet little studied component: mucin. Mucin is vital to maintenance of the tear film and functions as a tear film stabilizer. The condition of the precorneal tear film is a major determinant in the success of contact lens wear. Eighteen subjects free of ocular surface disease who had never worn contact lenses had the goblet cell density of their inferior bulbar conjunctiva determined by impression cytology. The subjects were then fit in a 38 percent water polymacon lens and their goblet cell density determined on a monthly basis for 6 months. Nearly a 2-fold increase in goblet cell density was observed in 88 percent of the subjects over the 6-month period. The first statistically significant increase occurred 5 months after the initiation of lens wear when the goblet cell density rose from 4.19-7.84 percent. We speculate the increase in goblet cells is an adaptive response of the ocular surface to a coated daily wear contact lens.

  17. Spontaneous oscillations of cell voltage, power density, and anode exit CO concentration in a PEM fuel cell.

    Science.gov (United States)

    Lu, Hui; Rihko-Struckmann, Liisa; Sundmacher, Kai

    2011-10-28

    The spontaneous oscillations of the cell voltage and output power density of a PEMFC (with PtRu/C anode) using CO-containing H(2) streams as anodic fuels have been observed during galvanostatic operating. It is ascribed to the dynamic coupling of the CO adsorption (poisoning) and the electrochemical CO oxidation (reactivating) processes in the anode chamber of the single PEMFC. Accompanying the cell voltage and power density oscillations, the discrete CO concentration oscillations at the anode outlet of the PEMFC were also detected, which directly confirms the electrochemical CO oxidation taking place in the anode chamber during galvanostatic operating. This journal is © the Owner Societies 2011

  18. Degradation of Solid Oxide Electrolysis Cells Operated at High Current Densities

    DEFF Research Database (Denmark)

    Tao, Youkun; Ebbesen, Sune Dalgaard; Mogensen, Mogens Bjerg

    2014-01-01

    In this work the durability of solid oxide cells for co-electrolysis of steam and carbon dioxide (45 % H2O + 45 % CO2 + 10 % H2) at high current densities was investigated. The tested cells are Ni-YSZ electrode supported, with a YSZ electrolyte and either a LSM-YSZ or LSCF-CGO oxygen electrode....... A current density of -1.5 and -2.0 A/cm2 was applied to the cell and the gas conversion was 45 % and 60 %, respectively. The cells were operated for a period of up to 700 hours. The electrochemical analysis revealed significant performance degradation for the ohmic process, oxygen ion interfacial transfer...

  19. Towards High Power Density Metal Supported Solid Oxide Fuel Cell for Mobile Applications

    DEFF Research Database (Denmark)

    Nielsen, Jimmi; Persson, Åsa H.; Muhl, Thuy Thanh

    2018-01-01

    For use of metal supported solid oxide fuel cell (MS-SOFC) in mobile applications it is important to reduce the thermal mass to enable fast startup, increase stack power density in terms of weight and volume and reduce costs. In the present study, we report on the effect of reducing the Technical...... loss, two different routes for increasing the porosity of the support layer and thus performance were explored. The first route is the introduction of gas channels by puncturing of the green tape casted support layer. The second route is modification of the co-sintering profile. In summary, the cell...... thickness and thus weight and volume was reduced and the cell power density at 0.7 V at 700°C was increased by 46% to 1.01 Wcm−2 at a fuel utilization of 48%. All modifications were performed on a stack technological relevant cell size of 12 cm × 12 cm....

  20. Enzyme controlled glucose auto-delivery for high cell density cultivations in microplates and shake flasks

    Directory of Open Access Journals (Sweden)

    Casteleijn Marco G

    2008-11-01

    Full Text Available Abstract Background Here we describe a novel cultivation method, called EnBase™, or enzyme-based-substrate-delivery, for the growth of microorganisms in millilitre and sub-millilitre scale which yields 5 to 20 times higher cell densities compared to standard methods. The novel method can be directly applied in microwell plates and shake flasks without any requirements for additional sensors or liquid supply systems. EnBase is therefore readily applicable for many high throughput applications, such as DNA production for genome sequencing, optimisation of protein expression, production of proteins for structural genomics, bioprocess development, and screening of enzyme and metagenomic libraries. Results High cell densities with EnBase are obtained by applying the concept of glucose-limited fed-batch cultivation which is commonly used in industrial processes. The major difference of the novel method is that no external glucose feed is required, but glucose is released into the growth medium by enzymatic degradation of starch. To cope with the high levels of starch necessary for high cell density cultivation, starch is supplied to the growing culture suspension by continuous diffusion from a storage gel. Our results show that the controlled enzyme-based supply of glucose allows a glucose-limited growth to high cell densities of OD600 = 20 to 30 (corresponding to 6 to 9 g l-1 cell dry weight without the external feed of additional compounds in shake flasks and 96-well plates. The final cell density can be further increased by addition of extra nitrogen during the cultivation. Production of a heterologous triosphosphate isomerase in E. coli BL21(DE3 resulted in 10 times higher volumetric product yield and a higher ratio of soluble to insoluble product when compared to the conventional production method. Conclusion The novel EnBase method is robust and simple-to-apply for high cell density cultivation in shake flasks and microwell plates. The

  1. A mathematical model of the current density distribution in electrochemical cells - AUTHORS’ REVIEW

    Directory of Open Access Journals (Sweden)

    PREDRAG M. ŽIVKOVIĆ

    2011-06-01

    Full Text Available An approach based on the equations of electrochemical kinetics for the estimation of the current density distribution in electrochemical cells is presented. This approach was employed for a theoretical explanation of the phenomena of the edge and corner effects. The effects of the geometry of the system, the kinetic parameters of the cathode reactions and the resistivity of the solution are also discussed. A procedure for a complete analysis of the current distribution in electrochemical cells is presented.

  2. Absolute choline concentration measured by quantitative proton MR spectroscopy correlates with cell density in meningioma

    Energy Technology Data Exchange (ETDEWEB)

    Yue, Qiang [University of Tsukuba, Department of Neurosurgery, Institute of Clinical Medicine, Tsukuba Science City, Ibaraki (Japan)]|[West China Hospital of Sichuan University, Huaxi MR Research Center, Department of Radiology, Chengdu (China); Shibata, Yasushi; Kawamura, Hiraku; Matsumura, Akira [University of Tsukuba, Department of Neurosurgery, Institute of Clinical Medicine, Tsukuba Science City, Ibaraki (Japan); Isobe, Tomonori [Kitasato University, Department of Medical Technology, School of Allied Health Sciences, Minato, Tokyo (Japan); Anno, Izumi [University of Tsukuba, Department of Radiology, Institute of Clinical Medicine, Tsukuba, Ibaraki (Japan); Gong, Qi-Yong [West China Hospital of Sichuan University, Huaxi MR Research Center, Department of Radiology, Chengdu (China)]|[University of Liverpool, Division of Medical Imaging, Faculty of Medicine, Liverpool (United Kingdom)

    2009-01-15

    This study was aimed to investigate the relationship between quantitative proton magnetic resonance spectroscopy (1H-MRS) and pathological changes in meningioma. Twenty-two meningioma cases underwent single voxel 1H-MRS (point-resolved spectroscopy sequence, repetition time/echo time = 2,000 ms/68, 136, 272 ms). Absolute choline (Cho) concentration was calculated using tissue water as the internal reference and corrected according to intra-voxel cystic/necrotic parts. Pathological specimens were stained with MIB-1 antibody to measure cell density and proliferation index. Correlation analysis was performed between absolute Cho concentration and cell density and MIB-1 labeled proliferation index. Average Cho concentration of all meningiomas before correction was 2.95 {+-} 0.86 mmol/kg wet weight. It was increased to 3.23 {+-} 1.15 mmol/kg wet weight after correction. Average cell density of all meningiomas was 333 {+-} 119 cells/HPF, and average proliferation index was 2.93 {+-} 5.72%. A linear, positive correlation between cell density and Cho concentration was observed (r = 0.650, P = 0.001). After correction of Cho concentration, the correlation became more significant (r = 0.737, P < 0.001). However, no significant correlation between Cho concentration and proliferation index was found. There seemed to be a positive correlation trend after correction of Cho concentration but did not reach significant level. Absolute Cho concentration, especially Cho concentration corrected according to intra-voxel cystic/necrotic parts, reflects cell density of meningioma. (orig.)

  3. [Oxidized low-density lipoprotein modulates differentiation of murine memory CD8+T cell subpopulations].

    Science.gov (United States)

    Zheng, Hua; Lin, Ze-Hang; Zhang, Yan-Mei; Zhou, Chen-Fei; Liu, Xuan; Wu, Sha

    2017-08-20

    To investigate effect of oxidized low-density lipoprotein (ox-LDL) on memory CD8 + T cell subpopulation differentiation in mice with autoimmune diabetes. Cultured splenic CD8 + T cells from pre-diabetic NOD mice isolated with magnetic beads were treated with 30 µg/mL ox-LDL and 10 U/mL interleukin-2 (IL-2) for 24 h and the control cells were treated with IL-2 only. Flow cytometry was used to determine the percentage of splenic CD8 + IFN-γ + T cells, expressions of CD8, CD44 and CD62L on the T cells, and the activation of T cell factor-1 (TCF-1) and STAT-3. The CD127 + memory T cells were purified and transplanted into the pre-diabetic NOD mice via the tail vein, and the blood glucose was recorded weekly and survival time of the mice was monitored. Treatment with ox-LDL significantly reduced islet β cell-specific cytotoxic CD8 + T cells as compared with the control group [(0.7∓0.03)% vs (2.7∓0.14)%, Peffector memory CD8 + T cells (Tem) in the total memory CD8 + T cells was reduced [(10.3∓0.71)% vs (30.3∓1.36)%, Pmemory T cells was significantly increased [(72.3∓3.8)% vs (55.1∓2.61)%, Pmemory T cells in pre-diabetic NOD mice obviously inhibited the increase of blood glucose and prolonged the survival time of the mice (Ptranscriptional factors TCF-1 and phosphorylation of STAT-3, inhibits the formation of effector memory CD8 + T cells with long-term cytotoxicity, but promote the generation of stem cell-like memory CD8 + T cells, which result in suppression of islet β cell-specific effector cytotoxic CD8 + T cell differentiation to lessen autoimmune injury to the islet β cells.

  4. Construction of concrete hot cells; requirements for shielding windows for concrete walls with different densities

    International Nuclear Information System (INIS)

    1987-10-01

    The shielding windows form part of the basic equipment of hot cells for remote handling, as defined in standard DIN 25 420 part 1. The draft standard in hand is intended to specify the design and manufacture requirements, especially with regard to main dimensions, sight quality, shielding effects, and radiation resistance. The standard refers to three types of shielding window with surface area design (product of density and wall thickness) corresponding to concrete walls of the densities 2.4, 3.4, and 4.0 g/cm 3 . The windows fit to three types of concrete of common usage, and the design is made for Co-60 radiation, with attenuation factors of about 10 4 , 10 6 , or 10 7 . For concrete walls with densities between these data, a shielding window suitable to the next higher density data is to be chosen. (orig./HP) [de

  5. Method of Fabrication of High Power Density Solid Oxide Fuel Cells

    Science.gov (United States)

    Pham, Ai Quoc; Glass, Robert S.

    2008-09-09

    A method for producing ultra-high power density solid oxide fuel cells (SOFCs). The method involves the formation of a multilayer structure cells wherein a buffer layer of doped-ceria is deposited intermediate a zirconia electrolyte and a cobalt iron based electrode using a colloidal spray deposition (CSD) technique. For example, a cobalt iron based cathode composed of (La,Sr)(Co,Fe)O(LSCF) may be deposited on a zirconia electrolyte via a buffer layer of doped-ceria deposited by the CSD technique. The thus formed SOFC have a power density of 1400 mW/cm.sup.2 at 600.degree. C. and 900 mW/cm.sup.2 at 700.degree. C. which constitutes a 2-3 times increased in power density over conventionally produced SOFCs.

  6. High Density Radiation Shielding Concretes for Hot Cells of 99mTc Project

    International Nuclear Information System (INIS)

    Sakr, K.

    2006-01-01

    High density concrete [more than 3.6 ton/m 3 (3.6x10 3 kg/m 3 )] was prepared to be used as a radiation shielding concrete (RSC) for hot-cells in gel technetium project at inshas to attenuate gamma radiation emitted from radioactive sources. different types of concrete were prepared by mixing local mineral aggregates mainly gravel and ilmenite . iron shots were added to the concrete mixture proportion as partial replacement of heavy aggregates to increase its density. the physical properties of prepared concrete in both plastic and hardened phases were investigated. compressive strength and radiation attenuation of gamma rays were determined. Results showed that ilmenite concrete mixed with iron shots had the highest density suitable to be use as RSC according to the chinese hot cell design requirements. Recommendations to avoid some technical problems of manufacturing radiation shielding concrete were maintained

  7. Density increment and decreased survival of rat red blood cells induced by cadmium

    International Nuclear Information System (INIS)

    Kunimoto, M.; Miura, T.

    1986-01-01

    Male Wistar rats were injected with CdCl 2 subcutaneously to examine in vivo effects of Cd on density and survival of red blood cells. During the 7 days after administration of 1.0 mg Cd/kg, the following sequence of events occurred: (1) a progressive increase in the amount of more dense red blood cells concomitant with a decrease in that of light red blood cells from the first to the third day; (2) an increase in the spleen weight at the third day; (3) a decrease in the hematocrit value and an increase in the amount of light red blood cells at the fifth day; and (4) a recovery of the hematocrit value at the seventh day. Five days after administration, the hematocrit value decreased in a dose-dependent mode and the decrease was significant at the 1% level at 1.0 and 1.5 mg Cd/kg. A highly significant splenomegaly was also observed at 0.5 to 1.5 mg Cd/kg. In order to label red blood cells in vivo, [ 3 H] diisopropylfluorophosphate ([ 3 H]DFP) was injected into rats. At Day 11, Cd at either 0.5 or 1.0 mg/kg was administered to [ 3 H]DFP-prelabeled animals. Cd administration accelerated 3 H-labeled red cell clearance from the blood. Six days after Cd administration, the radioactivity of red blood cells was 76 and 68% of the control at 0.5 and 1.0 mg Cd/kg, respectively. In vitro treatment of rat red density and accelerated in vivo clearance of red blood cells from the recipient circulation. These results show that Cd at low dose can cause anemia by increasing red cell density and by accelerating red cell sequestration, presumably in the spleen

  8. Bulk Heterojunction Solar Cells: Impact of Minor Structural Modifications to the Polymer Backbone on the Polymer-Fullerene Mixing and Packing and on the Fullerene-Fullerene Connecting Network

    KAUST Repository

    Wang, Tonghui

    2018-01-25

    The morphology of the active layer of a bulk heterojunction solar cell, made of a blend of an electron-donating polymer and an electron-accepting fullerene derivative, is known to play a determining role in device performance. Here, a combination of molecular dynamics simulations and long-range corrected density functional theory calculations is used to elucidate the molecular-scale effects that even minor structural changes to the polymer backbone can have on the “local” morphology; this study focuses on the extent of polymer–fullerene mixing, on their packing, and on the characteristics of the fullerene–fullerene connecting network in the mixed regions, aspects that are difficult to access experimentally. Three representative polymer donors are investigated: (i) poly[(5,6-difluoro-2,1,3-benzothiadiazol-4,7-diyl)-alt-(3,3′″-di(2-octyldodecyl)-2,2′;5′,2″;5″,2′″-quaterthiophen-5,5′″-diyl)] (PffBT4T-2OD); (ii) poly[(2,1,3-benzothiadiazol-4,7-diyl)-alt-(3,3′″-di(2-octyldodecyl)-2,2′;5′,2″;5″,2′″-quaterthiophen-5,5′″-diyl)] (PBT4T-2OD), where the fluorine atoms in the benzothiadiazole moieties of PffBT4T-2OD are replaced with hydrogen atoms; and (iii) poly[(2,2′-bithiophene)-alt-(4,7-bis((2-decyltetradecyl)thiophen-2-yl)-5,6-difluoro-2-propyl-2H-benzo[d][1,2,3]triazole)] (PT2-FTAZ), where the sulfur atoms in the benzothiadiazole moieties of PffBT4T-2OD are replaced with nitrogen atoms carrying a linear C3H7 side-chain; these polymers are mixed with the phenyl-C71-butyric acid methyl ester (PC71BM) acceptor. This study also discusses the nature of the charge-transfer electronic states appearing at the donor–acceptor interfaces, the electronic couplings relevant for the charge-recombination process, and the electron-transfer features between neighboring PC71BM molecules.

  9. Age-related decrease in rod bipolar cell density of the human retina ...

    Indian Academy of Sciences (India)

    PRAKASH

    Rod bipolar cells in ageing human retina. 293. J. Biosci. ... During normal ageing, the rods (and other neurones) undergo a significant decrease in density in the human retina ..... Brain Res. 84 293–300. Figure 3. Immunohistochemical demonstration of protein kinase C-α labelling in the macula of the 91-year-old donor. The.

  10. Vascular smooth muscle cells in cultures on low density polyethylene modified with plasma discharge and biofunctionalization

    Czech Academy of Sciences Publication Activity Database

    Pařízek, Martin; Kasálková, N.; Bačáková, Lucie; Kolářová, K.; Lisá, Věra; Švorčík, V.

    2009-01-01

    Roč. 12, 89-91 (2009), s. 25-28 ISSN 1429-7248 R&D Projects: GA AV ČR(CZ) KAN400480701; GA AV ČR(CZ) 1QS500110564 Institutional research plan: CEZ:AV0Z50110509 Keywords : Ar plasma discharge * low density polyethylene * vascular smooth muscle cells Subject RIV: EI - Biotechnology ; Bionics

  11. Cell openness manipulation of low density polyurethane foam for efficient sound absorption

    Science.gov (United States)

    Hyuk Park, Ju; Suh Minn, Kyung; Rae Lee, Hyeong; Hyun Yang, Sei; Bin Yu, Cheng; Yeol Pak, Seong; Sung Oh, Chi; Seok Song, Young; June Kang, Yeon; Ryoun Youn, Jae

    2017-10-01

    Satisfactory sound absorption using a low mass density foam is an intriguing desire for achieving high fuel efficiency of vehicles. This issue has been dealt with a microcellular geometry manipulation. In this study, we demonstrate the relationship between cell openness of polyurethane (PU) foam and sound absorption behaviors, both theoretically and experimentally. The objective of this work is to mitigate a threshold of mass density by rendering a sound absorber which shows a satisfactory performance. The cell openness, which causes the best sound absorption performance in all cases considered, was estimated as 15% by numerical simulation. Cell openness of PU foam was experimentally manipulated into desired ranges by adjusting rheological properties in a foaming reaction. Microcellular structures of the fabricated PU foams were observed and sound absorption coefficients were measured using a B&K impedance tube. The fabricated PU foam with the best cell openness showed better sound absorption performance than the foam with double mass density. We envisage that this study can help the manufacture of low mass density sound absorbing foams more efficiently and economically.

  12. Age-related decrease in rod bipolar cell density of the human retina ...

    Indian Academy of Sciences (India)

    PRAKASH

    Age-related decrease in rod bipolar cell density of the human retina: an immunohistochemical study. P AGGARWAL, T C NAG and S WADHWA*. Department of Anatomy, All India Institute of Medical Sciences, New Delhi 110029, India. *Corresponding author (Fax, 91-11-26588663; Email, shashiwadhwa@hotmail.com).

  13. Stomatal and pavement cell density linked to leaf internal CO2 concentration

    Czech Academy of Sciences Publication Activity Database

    Šantrůček, Jiří; Vráblová, M.; Šimková, Marie; Hronková, Marie; Drtinová, M.; Květoň, J.; Vrábl, D.; Kubásek, J.; Macková, J.; Wiesnerová, Dana; Neuwithová, J.; Schreiber, L.

    2014-01-01

    Roč. 114, č. 2 (2014), s. 191-202 ISSN 0305-7364 R&D Projects: GA ČR(CZ) GAP501/12/1261 Institutional support: RVO:60077344 Keywords : Stomatal density * Stomata development * Pavement cells Subject RIV: CE - Biochemistry Impact factor: 3.654, year: 2014

  14. Packing for food irradiation

    International Nuclear Information System (INIS)

    Chmielewski, A.G.

    2006-01-01

    Joint FAO/IAEA/WHO Expert Committee approved the use of radiation treatment of foods. Nowadays food packaging are mostly made of plastics, natural or synthetic, therefore effect of irradiation on these materials is crucial for packing engineering for food irradiation technology. By selecting the right polymer materials for food packaging it can be ensured that the critical elements of material and product performance are not compromised. When packaging materials are in contact with food at the time of irradiation that regulatory approvals sometimes apply. The review of the R-and-D and technical papers regarding material selection, testing and approval is presented in the report. The most information come from the USA where this subject is well elaborated, the International Atomic Energy Agency (IAEA) reports are reviewed as well. The report can be useful for scientists and food irradiation plants operators. (author)

  15. Polarizable protein packing

    KAUST Repository

    Ng, Albert H.

    2011-01-24

    To incorporate protein polarization effects within a protein combinatorial optimization framework, we decompose the polarizable force field AMOEBA into low order terms. Including terms up to the third-order provides a fair approximation to the full energy while maintaining tractability. We represent the polarizable packing problem for protein G as a hypergraph and solve for optimal rotamers with the FASTER combinatorial optimization algorithm. These approximate energy models can be improved to high accuracy [root mean square deviation (rmsd) < 1 kJ mol -1] via ridge regression. The resulting trained approximations are used to efficiently identify new, low-energy solutions. The approach is general and should allow combinatorial optimization of other many-body problems. © 2011 Wiley Periodicals, Inc. J Comput Chem, 2011 Copyright © 2011 Wiley Periodicals, Inc.

  16. Corneal endothelial cell density and morphology in low and moderate myopic Chinese eyes

    Directory of Open Access Journals (Sweden)

    Jane Mei Chun

    2013-08-01

    Full Text Available AIM: To describe and compare the corneal endothelial cell density and morphology in young, low and moderate myopic Chinese adults in Malaysian Chinese population.METHODS: Non-contact specular microscopy (Topcon SP3000P, Tokyo, Japan was performed in low (n=78; 21.22±1.51 years and moderate (n=78; 21.82±1.40 years myopic subjects. The mean of three consecutive measurements of endothelial cell density (MCD, coefficient of variation (CV in the cell size, and hexagonal appearance of the cell were obtained.RESULTS: In low myopic eyes the MCD was 3 063.0±176.2/mm2, the mean CV was 33.4±4.0% and the mean hexagonal appearance of the cell was 57.9±2.7%. In moderate myopic eyes the MCD was 2961.6±159.0/mm2, the mean CV was 33.9±3.6% and mean hexagonal appearance of the cell was 56.2±4.7%. There were statistically significant differences in MCD (PPCONCLUSION:The corneal endothelial cell layer in more myopic eyes tends to have less MCD and cell hexagonality compared to lower myopic eyes. Nevertheless, there is no significant difference in CV between low and moderate myopic eyes.

  17. Avaliação cronológica da variação no volume globular sanguíneo de bovinos leiteiros Cronological evaluation of variation in packed cell volume on dairy cattle

    Directory of Open Access Journals (Sweden)

    Wilmar Sachetin Marçal

    1995-01-01

    Full Text Available Os autores avaliaram a variação no volume globular sangüíneo de 321 bovinos da raça Holandês preta e branca, sadios e criados em granjas leiteiras no Estado de São Paulo. Todos os animais trabalhados na presente pesquisa eram sadios, não reagentes ao vírus da Leucose Bovina, livres de hemoparasitas, brucelose e tuberculose. O volume globular sangüíneo foi efetuado através do método do hematócrito com tubos capilares. Os resultados mostram haver influência da idade sobre o volume globular sangüíneo, com valores médios encontrados de 30,12 ± 2,72%.The packet cell volume was evaluated by the authors in 321 healthy female Holstein cattle raised at Campinas dairy region. São Paulo State. All the animais used in this assay were healthy and free of Leucosis, Tuberculosis, Brucellosis and blood parasites. The packed cell volume has been studied by method of hematocrit with capilary tubos. The results showed an influence of age on packed cell volume with average reference values of 30.12 ± 2.72%.

  18. Modeling of Li-Ion Battery Packs as Basis for Design of Battery Thermal Management Systems

    DEFF Research Database (Denmark)

    Coman, Paul Tiberiu

    Li-ion batteries are one of the most popular battery types on the market, due to their prime properties such as high capacity, low self-discharge rate, zero-maintenance, high energy density and long lifetime. However, safety still remains a major drawback, due to overheating and thermal runaway...... conservation equations, and the results were compared against experimental data from the open literature; 2. A simplified thermal runaway model for investigating the propagation of thermal runaway in a battery pack designed by NASA for astronaut spacesuits. A simplified model was initially built for single...... battery cells with an internal short circuit device (ISCD) implanted inside, used for triggering thermal runaway at low temperatures. The simplified lumped model was then coupled with a 2D thermal FEM for investigating the pack design. The simplification consists of implementing an efficiency factor term...

  19. Phage-Bacterial Dynamics with Spatial Structure: Self Organization around Phage Sinks Can Promote Increased Cell Densities.

    Science.gov (United States)

    Bull, James J; Christensen, Kelly A; Scott, Carly; Jack, Benjamin R; Crandall, Cameron J; Krone, Stephen M

    2018-01-29

    Bacteria growing on surfaces appear to be profoundly more resistant to control by lytic bacteriophages than do the same cells grown in liquid. Here, we use simulation models to investigate whether spatial structure per se can account for this increased cell density in the presence of phages. A measure is derived for comparing cell densities between growth in spatially structured environments versus well mixed environments (known as mass action). Maintenance of sensitive cells requires some form of phage death; we invoke death mechanisms that are spatially fixed, as if produced by cells. Spatially structured phage death provides cells with a means of protection that can boost cell densities an order of magnitude above that attained under mass action, although the effect is sometimes in the opposite direction. Phage and bacteria self organize into separate refuges, and spatial structure operates so that the phage progeny from a single burst do not have independent fates (as they do with mass action). Phage incur a high loss when invading protected areas that have high cell densities, resulting in greater protection for the cells. By the same metric, mass action dynamics either show no sustained bacterial elevation or oscillate between states of low and high cell densities and an elevated average. The elevated cell densities observed in models with spatial structure do not approach the empirically observed increased density of cells in structured environments with phages (which can be many orders of magnitude), so the empirical phenomenon likely requires additional mechanisms than those analyzed here.

  20. Superhydrophilic-Superhydrophobic Patterned Surfaces as High-Density Cell Microarrays: Optimization of Reverse Transfection.

    Science.gov (United States)

    Ueda, Erica; Feng, Wenqian; Levkin, Pavel A

    2016-10-01

    High-density microarrays can screen thousands of genetic and chemical probes at once in a miniaturized and parallelized manner, and thus are a cost-effective alternative to microwell plates. Here, high-density cell microarrays are fabricated by creating superhydrophilic-superhydrophobic micropatterns in thin, nanoporous polymer substrates such that the superhydrophobic barriers confine both aqueous solutions and adherent cells within each superhydrophilic microspot. The superhydrophobic barriers confine and prevent the mixing of larger droplet volumes, and also control the spreading of droplets independent of the volume, minimizing the variability that arises due to different liquid and surface properties. Using a novel liposomal transfection reagent, ScreenFect A, the method of reverse cell transfection is optimized on the patterned substrates and several factors that affect transfection efficiency and cytotoxicity are identified. Higher levels of transfection are achieved on HOOC- versus NH 2 -functionalized superhydrophilic spots, as well as when gelatin and fibronectin are added to the transfection mixture, while minimizing the amount of transfection reagent improves cell viability. Almost no diffusion of the printed transfection mixtures to the neighboring microspots is detected. Thus, superhydrophilic-superhydrophobic patterned surfaces can be used as cell microarrays and for optimizing reverse cell transfection conditions before performing further cell screenings. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Interface state density effect on the performance of graphene silicon heterojunction solar cell

    Science.gov (United States)

    Kuang, Yawei; Lin, Bencai; Ma, Yulong; Liu, Yushen; Yang, Xifeng; Zhang, Debao; Shao, Zhenguang; Feng, Jinfu

    2016-01-01

    A planar structure consisting of graphene layer as the hole transport material, and n-type silicon as substrate is simulated. The degradation of this cell caused by high interface state density has been carried out. The simulated results match published experimental results indicating the accuracy of the physics-based model. Using this model, the effect of interface state density as zero, 1×1016cm-2, 1×1017cm-2 on the photovoltaic performance has been studied. The obtained IV and EQE characteristic based on realistic parameters shows that the interface state playing a prominent role in graphene silicon schottky contact.

  2. Direct alcohol fuel cells: toward the power densities of hydrogen-fed proton exchange membrane fuel cells.

    Science.gov (United States)

    Chen, Yanxin; Bellini, Marco; Bevilacqua, Manuela; Fornasiero, Paolo; Lavacchi, Alessandro; Miller, Hamish A; Wang, Lianqin; Vizza, Francesco

    2015-02-01

    A 2 μm thick layer of TiO2 nanotube arrays was prepared on the surface of the Ti fibers of a nonwoven web electrode. After it was doped with Pd nanoparticles (1.5 mgPd  cm(-2) ), this anode was employed in a direct alcohol fuel cell. Peak power densities of 210, 170, and 160 mW cm(-2) at 80 °C were produced if the cell was fed with 10 wt % aqueous solutions of ethanol, ethylene glycol, and glycerol, respectively, in 2 M aqueous KOH. The Pd loading of the anode was increased to 6 mg cm(-2) by combining four single electrodes to produce a maximum peak power density with ethanol at 80 °C of 335 mW cm(-2) . Such high power densities result from a combination of the open 3 D structure of the anode electrode and the high electrochemically active surface area of the Pd catalyst, which promote very fast kinetics for alcohol electro-oxidation. The peak power and current densities obtained with ethanol at 80 °C approach the output of H2 -fed proton exchange membrane fuel cells. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. The invasive microalga Chrysophaeum taylorii: Interactive stressors regulate cell density and mucilage production.

    Science.gov (United States)

    Caronni, Sarah; Calabretti, Chiara; Cavagna, Gianluca; Ceccherelli, Giulia; Delaria, Maria Anna; Macri, Giovanni; Navone, Augusto; Panzalis, Pieraugusto

    2017-08-01

    The benthic mucilage producing microalga Chrysophaeum taylorii Lewis and Bryan (Pelagophyceae) has recently received attention for its rapid spread in the Mediterranean Sea, where its blooms have remarkable detrimental effects. So far no information on C. taylorii response to multiple stressors, especially in terms of mucilage hyperproduction, is available in the literature yet, and a manipulative field experiment in this topic was designed in Tavolara Punta Coda Cavallo Marine Protected Area. The aim of the study was to test the effects of nutrient enrichment (addition of nutrients), mechanical disturbance (partial and total benthic organisms removal) and hydrodynamics (increased water turbulence) on C. taylorii cell density and mucilage abundance. To the purpose, the three above mentioned stressors were simulated and the three treatments were assigned to 20 × 20 cm plots following a full-factorial design (n = 3). Interactive effects of the three stressors affected significantly both benthic C. taylorii cell density and mucilage cover although differently. Mechanical disturbance and high hydrodynamics produced consistent effects on cell density and mucilage production (i.e. the former factor enhancing and the latter decreasing). Nutrient enrichment on the contrary led to contrasting effects, promoting cell abundance and inhibiting mucilage production. Therefore, important mucilage blooms are expected in oligotrophic sheltered coastal locations where barren areas are present. Copyright © 2017 Elsevier Ltd. All rights reserved.

  4. Increased cell proliferation and mucocyte density in the sea anemone Aiptasia pallida recovering from bleaching.

    Directory of Open Access Journals (Sweden)

    David Fransolet

    Full Text Available Recovery of coral after bleaching episodes is a critical period for the health of the reef ecosystem. While events such as symbiont (genus Symbiodinium shifting/shuffling or tissue apoptosis have been demonstrated to occur following bleaching, little is known concerning tissue recovery or cell proliferation. Here, we studied the sea anemone Aiptasia pallida exposed to a transient elevation of water temperature combined with high illumination (33°C and 1900 µmol photons x m(-2 x s(-1 for 30 h. Following such treatment bleached anemones showed a significant reduction of their Symbiodinium density. Cell proliferation in the ectodermis and gastrodermis was determined by assessing the densities of cells labeled with a thymidine analogue (EdU. Cell proliferation significantly increased during the first day following stress in both tissue types. This increased cell proliferation returned to pre-stress values after one week. Although cell proliferation was higher in the ectodermis in absence of stress, it was relatively more pronounced in the gastrodermis of stressed anemones. In addition, the ratio of ectodermal mucocytes significantly increased three weeks after induced stress. These results suggest that thermal/photic stress coupled with the loss of the symbionts is able to enhance cell proliferation in both gastrodermis and ectodermis of cnidarians. While new cells formed in the gastrodermis are likely to host new Symbiodinium, the fate of new cells in the ectodermis was only partially revealed. Some new ectodermal cells may, in part, contribute to the increased number of mucocytes which could eventually help strengthen the heterotrophic state until restoration of the symbiosis.

  5. Nasal packing with ventilated nasal packs; a comparison with traditional vaseline nasal pack

    International Nuclear Information System (INIS)

    Alam, J.; Siddiqui, M.W.; Abbas, A.; Sami, M.; Ayub, Z.

    2017-01-01

    To compare the benefits of ventilated nasal packing with traditional vaseline guaze nasal packing. Study Design: Randomized controlled trial. Place and Duration of Study: This study was conducted at CMH Multan, from Jun 2014 to Dec 2014. Material and Methods: In this study, sample size of 80 patients was calculated using WHO calculator. Patients were divided in two groups using lottery method endotracheal tube and piece of surgical glove filled with ribbon guaze was utilized for fabricated ventilated nasal pack and compared with traditional nasal packs. Nasal obstruction and sleep disturbance were studied at eight hours and twenty-four hours following surgery using visual analog scale. Results: Mean nasal obstruction with ventilated nasal pack was 45.62 +- 6.17 and with Vaseline nasal pack was 77.67 +- 4.85 which was statistically significant (p=0.001) in both the groups. Mean sleep disturbance in both the groups was 46.32 +- 5.23 and 68.75 +- 2.70 respectively which was statistically significant (p=0.001) in both the groups. Conclusion: Patients with ventilated nasal packs were found to have better tolerance to nasal packs due to less nasal obstruction and sleep disturbance

  6. FROM THE PACKED TOWERS

    Directory of Open Access Journals (Sweden)

    Valderi D. Leite

    2013-01-01

    Full Text Available About 245 thousand tones of municipal solid w aste are collected daily in Brazil. Nearly 32 thousand tones of the collected amount are treated in sanitary landfill, which generates biogas and leachate as byproduct. The leachate resulting from sanitary landfill contains high concentration of carbonaceous and nitrogenized material. The crucial question is that the biodegradation of the carbonaceous material is difficult as long as the nitrogenized material is presen t in the form of ammoniacal nitrogen (NH 4 + , which compromises performance of biological tr eatment process. Therefore, a physical and chemical treatment of the leachate should be done before its biological treatment, especially for reduction of ammoniacal nitr ogen concentration and for propitiating the realization of application of biological treatment. The treatment of leachate requires specific consideration, which is not needed fo r other types of waste. In the specific case in this study, where ammoniacal nitrogen concentration was about 2,200 mgN L -1 and the BOD 5 /COD ratio was 0.3, the study of ammonia stripping process was performed. Ammonia stripping process was studied in pack ed towers of 35 L capacity each and the parameters investigated were pH, ratio of contact area/leach volume and the aeration time. One of the parameters that influenced most in efficiency of ammonia stripping process was pH of the leachate since it contributes in conversion of ammoniacal nitrogen from NH 4 + to NH 3 .

  7. Enzymatically Modified Low-Density Lipoprotein Promotes Foam Cell Formation in Smooth Muscle Cells via Macropinocytosis and Enhances Receptor-Mediated Uptake of Oxidized Low-Density Lipoprotein.

    Science.gov (United States)

    Chellan, Bijoy; Reardon, Catherine A; Getz, Godfrey S; Hofmann Bowman, Marion A

    2016-06-01

    Enzyme-modified nonoxidized low-density lipoprotein (ELDL) is present in human atherosclerotic lesions. Our objective is to understand the mechanisms of ELDL uptake and its effects on vascular smooth muscle cells (SMC). Transformation of murine aortic SMCs into foam cells in response to ELDL was analyzed. ELDL, but not acetylated or oxidized LDL, was potent in inducing SMC foam cell formation. Inhibitors of macropinocytosis (LY294002, wortmannin, amiloride) attenuated ELDL uptake. In contrast, inhibitors of receptor-mediated endocytosis (dynasore, sucrose) and inhibitor of caveolae-/lipid raft-mediated endocytosis (filipin) had no effect on ELDL uptake in SMC, suggesting that macropinocytosis is the main mechanism of ELDL uptake by SMC. Receptor for advanced glycation end products (RAGE) is not obligatory for ELDL-induced SMC foam cell formation, but primes SMC for the uptake of oxidized LDL in a RAGE-dependent manner. ELDL increased intracellular reactive oxygen species, cytosolic calcium, and expression of lectin-like oxidized LDL receptor-1 in wild-type SMC but not in RAGE(-/-) SMC. The macropinocytotic uptake of ELDL is regulated predominantly by intracellular calcium because ELDL uptake was completely inhibited by pretreatment with the calcium channel inhibitor lacidipine in wild-type and RAGE(-/-) SMC. This is in contrast to pretreatment with PI3 kinase inhibitors which completely prevented ELDL uptake in RAGE(-/-) SMC, but only partially in wild-type SMC. ELDL is highly potent in inducing foam cells in murine SMC. ELDL endocytosis is mediated by calcium-dependent macropinocytosis. Priming SMC with ELDL enhances the uptake of oxidized LDL. © 2016 American Heart Association, Inc.

  8. The large-scale correlations of multi-cell densities and profiles, implications for cosmic variance estimates

    OpenAIRE

    Codis, Sandrine; Bernardeau, Francis; Pichon, Christophe

    2016-01-01

    In order to quantify the error budget in the measured probability distribution functions of cell densities, the two-point statistics of cosmic densities in concentric spheres is investigated. Bias functions are introduced as the ratio of their two-point correlation function to the two-point correlation of the underlying dark matter distribution. They describe how cell densities are spatially correlated. They are computed here via the so-called large deviation principle in the quasi-linear reg...

  9. Bone marrow-derived cells for cardiovascular cell therapy: an optimized GMP method based on low-density gradient improves cell purity and function.

    Science.gov (United States)

    Radrizzani, Marina; Lo Cicero, Viviana; Soncin, Sabrina; Bolis, Sara; Sürder, Daniel; Torre, Tiziano; Siclari, Francesco; Moccetti, Tiziano; Vassalli, Giuseppe; Turchetto, Lucia

    2014-09-27

    Cardiovascular cell therapy represents a promising field, with several approaches currently being tested. The advanced therapy medicinal product (ATMP) for the ongoing METHOD clinical study ("Bone marrow derived cell therapy in the stable phase of chronic ischemic heart disease") consists of fresh mononuclear cells (MNC) isolated from autologous bone marrow (BM) through density gradient centrifugation on standard Ficoll-Paque. Cells are tested for safety (sterility, endotoxin), identity/potency (cell count, CD45/CD34/CD133, viability) and purity (contaminant granulocytes and platelets). BM-MNC were isolated by density gradient centrifugation on Ficoll-Paque. The following process parameters were optimized throughout the study: gradient medium density; gradient centrifugation speed and duration; washing conditions. A new manufacturing method was set up, based on gradient centrifugation on low density Ficoll-Paque, followed by 2 washing steps, of which the second one at low speed. It led to significantly higher removal of contaminant granulocytes and platelets, improving product purity; the frequencies of CD34+ cells, CD133+ cells and functional hematopoietic and mesenchymal precursors were significantly increased. The methodological optimization described here resulted in a significant improvement of ATMP quality, a crucial issue to clinical applications in cardiovascular cell therapy.

  10. Systems biology. Conditional density-based analysis of T cell signaling in single-cell data.

    Science.gov (United States)

    Krishnaswamy, Smita; Spitzer, Matthew H; Mingueneau, Michael; Bendall, Sean C; Litvin, Oren; Stone, Erica; Pe'er, Dana; Nolan, Garry P

    2014-11-28

    Cellular circuits sense the environment, process signals, and compute decisions using networks of interacting proteins. To model such a system, the abundance of each activated protein species can be described as a stochastic function of the abundance of other proteins. High-dimensional single-cell technologies, such as mass cytometry, offer an opportunity to characterize signaling circuit-wide. However, the challenge of developing and applying computational approaches to interpret such complex data remains. Here, we developed computational methods, based on established statistical concepts, to characterize signaling network relationships by quantifying the strengths of network edges and deriving signaling response functions. In comparing signaling between naïve and antigen-exposed CD4(+) T lymphocytes, we find that although these two cell subtypes had similarly wired networks, naïve cells transmitted more information along a key signaling cascade than did antigen-exposed cells. We validated our characterization on mice lacking the extracellular-regulated mitogen-activated protein kinase (MAPK) ERK2, which showed stronger influence of pERK on pS6 (phosphorylated-ribosomal protein S6), in naïve cells as compared with antigen-exposed cells, as predicted. We demonstrate that by using cell-to-cell variation inherent in single-cell data, we can derive response functions underlying molecular circuits and drive the understanding of how cells process signals. Copyright © 2014, American Association for the Advancement of Science.

  11. Noninvasive prenatal diagnosis. Use of density gradient centrifugation, magnetically activated cell sorting and in situ hybridization

    DEFF Research Database (Denmark)

    Campagnoli, C; Multhaupt, H A; Ludomirski, A

    1997-01-01

    centrifugation and dual antibody labeling methods. The protocol was designed to compare the efficacy of antitransferrin receptor (CD71)/antiglycophorin A (GPA) antibodies with antithrom-bospondin receptor (CD36)/anti-GPA antibodies in identifying nucleated erythrocytes in maternal blood. Cytospin preparations...... cells recovered did not differ. Seven of seven male pregnancies were correctly identified. One case of trisomy 21 was detected. CONCLUSION: The in situ hybridization analysis of fetal nucleated erythrocytes isolated from maternal blood using single density gradient centrifugation, anti-CD71/anti......OBJECTIVE: To develop a noninvasive method suitable for clinical prenatal diagnosis. STUDY DESIGN: Fetal nucleated erythrocytes were separated from peripheral blood of 17 healthy pregnant women using small magnetically activated cell sorting columns (MiniMACS) following density gradient...

  12. Results of Current Density Distribution Mapping in PEM Fuel Cells Dependent on Operation Parameters

    Directory of Open Access Journals (Sweden)

    Zbigniew A. Styczynski

    2013-07-01

    Full Text Available This paper presents in situ measurements of a newly developed current density measurement system for proton exchange membrane fuel cells (PEMFC. While the functional principle and technical evaluation of the measurement system were presented in a previous paper, this paper analyzes the influence of various operation parameters, including multiple start-stop operation, at the anode, cathode and cooling locations on the distribution and long-term development of the current density. The system was operated for 500 h over two years with long periods of inactivity between measurements. The measurement results are evaluated and provide additional information on how to optimize the operation modes of fuel cells, including the start and stop of such systems as well as the water balance.

  13. Aplicação de métodos estatísticos na otimização da densidade de empacotamento de distribuições de pós de alumina Optimization of the packing density of alumina powder distributions using statistical techniques

    Directory of Open Access Journals (Sweden)

    A. P. Silva

    2004-12-01

    Full Text Available Fatores como a distribuição granulométrica e a morfologia condicionam as propriedades físicas de sistemas particulados (e.g. misturas de pós, pastas, concretos refratários, entre as quais a densidade de empacotamento. Podem ser encontrados, na literatura, vários modelos para a otimização da distribuição de tamanhos de partículas que maximiza o empacotamento, todos desenvolvidos para sistemas de esferas perfeitas (e.g. Furnas, Andreasen, Alfred. Neste trabalho, pós de alumina comercial (reativa e tabular foram separados em nove frações granulométricas e, recorrendo a dois procedimentos distintos, construíram-se seis sistemas ternários diferentes e complementares de tamanhos de partículas. Usando a metodologia das superfícies de resposta e técnicas de análise estatística afins (programa de cálculo Statistica obteve-se, em ambos os casos, a distribuição granulométrica que maximiza a densidade de empacotamento. Por comparação com as distribuições granulométricas teóricas, ficou demonstrada a validade do modelo teórico de Alfred para esferas perfeitas. Os resultados obtidos demonstram, assim, que o efeito prejudicial da não esfericidade das partículas pode ser, na realidade, compensado pela otimização da distribuição granulométrica global.Particle size distribution and morphology are among the factors that affect the physical properties of particulate systems (e.g. powder mixtures, pastes, castable refractories. One such property is packing density. There are, in the literature, models that optimise particle size distributions for maximum packing density, all of them derived for spherical particles (e.g. Furnas, Andreasen, Alfred. In this work, commercial alumina powders (reactive and tabular were divided into nine particle size classes. Following two different approaches, the latter were used to build six different ternary systems of complementary particle sizes. Using the response surface methodology and

  14. Convective cell excitation by inertial Alfven waves in a low density plasma

    International Nuclear Information System (INIS)

    Pokhotelov, O.A.; Onishchenko, O.G.; Sagdeev, R.Z.; Srenflo, L.; Balikhin, M.A.

    2005-01-01

    The parametric interaction of inertial Alfven waves with large-scale convective cells in a low-density plasma is investigated. It is shown that, in plasmas where the Alfven velocity is comparable to or exceeds the speed of light, the parametric interaction is substantially suppressed. A compact expression for the optimal scale and instability growth rate of the fastest growing mode is obtained [ru

  15. "Bleaching" glycerol in a microfluidic fuel cell to produce high power density at minimal cost.

    Science.gov (United States)

    Martins, Cauê A; Ibrahim, Omar A; Pei, Pei; Kjeang, Erik

    2018-01-07

    Glycerol/bleach flow-through microfluidic fuel cells are presented. Carbon paper-modified Pt/C nanoparticles were used as the anode and cathode. Glycerol oxidation in alkaline medium was tested against hypochlorite reduction in alkaline and acidic media. The mixed media system displayed a power density of 315 mW cm -2 and an open circuit voltage of 1.9-2.0 V.

  16. High cell density strategy for poly(3-hydroxybutyrate production by Cupriavidus necator

    Directory of Open Access Journals (Sweden)

    J. L. Ienczak

    2011-12-01

    Full Text Available Poly(3-hydroxybutyrate (P(3HB is a carbon and intracellular storage source for different microorganisms and its production can achieve high productivities by means of high cell density cultures. The aim of this study was to propose a high cell density strategy for P(3HB production by Cupriavidus necator. The exponential growth phase demands an accurate control of the oxygen transfer system in the bioreactor, due to maximum specific growth rate (µXr, and, consequently, a maximum specific oxygen uptake rate (QO2, in addition to significant residual biomass (Xr growth in high cell density cultures. In this context, this work investigated the strategy for obtaining high cell density, with the inclusion of a linear growth phase for P(3HB production by C. necator in a fed-batch culture. The linear growth phase was included between the exponential growth phase and the P(3HB production phase as a strategy to reduce the specific growth rate (µXr and specific oxygen uptake rate (QO2, with constant residual biomass growth rate (d(V.Xr/dt = k = constant and linear increase of biomass. Three strategies of culture were performed. The results showed that a high residual biomass concentration (30 gXr.L-1 can be reached by the inclusion of the linear growth strategy and specific growth rates (µXr between 0.08 and 0.05 h-1, at the beginning of the production phase, are necessary to attain a high P(3HB productivity.

  17. Packing stress reduction in polymer-lipid monolayers at the air-water interface: An X-ray grazing-incidence diffraction and reflectivity study

    Energy Technology Data Exchange (ETDEWEB)

    Kuhl, T.L.; Majewski, J.; Howes, P.B.; Kjaer, K.; Nahmen, A. von; Lee, K.Y.C.; Ocko, B.; Israelachvili, J.N.; Smith, G.S.

    1999-08-25

    Using synchrotron grazing-incidence X-ray diffraction (GIXD) and reflectivity (XR), the authors have determined the in-plane and out-of-plane structure of phospholipid monolayers at the air-water interface as a function of hydrophilic lipid headgroup size. Di-stearoyl-phosphatidyl-ethanolamine (DSPE) lipid monolayers were systematically modified by chemically grafting hydrophilic poly(ethylene glycol) (PEG) chains of MW = 90 g/mol (2 ethylene oxide, EO, units), MW = 350 g/mol (8 EO units), and MW = 750 g/mol (17 EO units) to the lipid headgroups. The monolayers were studied in the solid phase at a surface pressure of 42 mN/m. At these high lipid packing densities, the PEG chains are submerged in the water subphase. The increased packing stresses from these bulky polymer headgroups distort the unit cell and the in-plane packing modes of the monolayers, leading to large out-of-plane alterations and staggering of the lipid molecules. Surprisingly, a change in the molecular packing of the monolayer toward higher packing densities (lower area per molecule) was observed on increasing the PEG MW to 750 g/mol (17 EO units). This rearrangement of the monolayer structure may be due to a conformational change in the PEG chains.

  18. RelE-Mediated Dormancy Is Enhanced at High Cell Density in Escherichia coli

    OpenAIRE

    Tashiro, Yosuke; Kawata, Koji; Taniuchi, Asami; Kakinuma, Kenji; May, Thithiwat; Okabe, Satoshi

    2012-01-01

    Bacteria show remarkable adaptability under several stressful conditions by shifting themselves into a dormant state. Less is known, however, about the mechanism underlying the cell transition to dormancy. Here, we report that the transition to dormant states is mediated by one of the major toxin-antitoxin systems, RelEB, in a cell density-dependent manner in Escherichia coli K-12 MG1655. We constructed a strain, IKA121, which expresses the toxin RelE in the presence of rhamnose and lacks chr...

  19. Evaluation of Mast Cell and Blood Vessel Density in Inflammatory Periapical Lesions

    Directory of Open Access Journals (Sweden)

    Safoura Seifi

    2012-01-01

    Full Text Available Introduction: Radicular cystsand periapical granulomas are the most common periapical inflammatory lesions. However, the role of cellular immunity and microvessels in their pathogenesis remains unknown. The aim of this study was to evaluate the mast cell density (MCD, mircovessel density (MVD and investigating the correlation between their densities with each other in the above mentioned lesions.Materials & Methods: In this descriptive cross-sectional study, 40 paraffin blocks of mentioned lesions were selected from achieves of School of Dentistry, Babol University of Medical Sciences. Three sections were prepared from each block and stained by hematoxylin-eosin, toluidine blue, and immunohistochemically for CD34 to determine the score of inflammation, presence of mast cells and degranulatedmast cells (DMCs, and MVD, respectively. The correlation between MCD and either inflammatory infiltrate or MVD was evaluated. Data analyzed by t student, Mann-Whitney and Spearman test.Results: Mast cells were present in all periapical inflammatory lesions; 15.4±14.8 for MCD, 7.2±6.1 for DMCs, and the ratio of DMCs to total number of MCs was 0.354±0.166 and 14.8+4.44 for blood vessel density in radicular cyst and 8.52±6.75, 2.91±2.1, 0.196±0.194 and 13±8.02 in periapical granulomas, respectively. There was a positive correlation between MCD and MVD in radicular cyst (P=0.03, r=0.341, but not in periapical granulomas (P=0.6, r=0.124. MCD and MVD increased with the score of inflammation in radicular cyst (P=0.001, r=0.7 and periapical granuloma (P=0.012, r=0.54.Conclusion: Mast cells and microvessels play a role in pathogenesis of periapical inflammatory lesions. In this study, the density of mast cells and DMCs in radicular cyst was higher than periapical granulomas, but no difference was observed regarding MVD in periapical inflammatory lesions. It seems that the relationship between MCD and MVD is different based on the clinical stage of periapical

  20. Cheese whey-induced high-cell-density production of recombinant proteins in Escherichia coli

    Directory of Open Access Journals (Sweden)

    Neubauer Peter

    2003-04-01

    Full Text Available Abstract Background Use of lactose-rich concentrates from dairy processes for the induction of recombinant gene's expression has not received much attention although they are interesting low cost substrates for production of recombinant enzymes. Applicability of dairy waste for induction of recombinant genes in Escherichia coli was studied. Clones expressing Lactobacillus phage muramidase and Lactobacillus alcohol dehydrogenase were used for the experiments. Results Shake flask cultivations in mineral salt medium showed that cheese whey or deproteinised whey induced gene expression as efficiently as IPTG (isopropyl-β-D-thiogalactopyranoside or pure lactose. Addition of yeast extract or proteolytically degraded whey proteins did not improve the recombinant protein yield. In contrast, addition of yeast extract to the well-balanced mineral salt medium decreased the product yield. Feeding with glycerol provided sufficient amount of easily assimilable carbon source during the induction period without preventing lactose intake and induction by lactose. High-cell-density fed-batch cultivations showed that product yields comparable to IPTG-induction can be achieved by feeding bacteria with a mixture of glycerol and concentrated whey permeate during the induction. Conclusion Whey and concentrated whey permeate can be applied as an alternative inducer in recombinant high-cell-density fed-batch fermentations. The yield of the recombinant product was comparable to fermentations induced by IPTG. In low-cell-density shake flask experiments the yield was higher with whey or whey permeate than with IPTG.

  1. The mechanical behaviour of packed particulates

    Energy Technology Data Exchange (ETDEWEB)

    Dutton, R

    1998-01-01

    Within the Canadian Nuclear Fuel Waste Management program, the central concept is to package used fuel in containers that would be deposited in an underground vault in a plutonic rock formation. To provide internal mechanical support for the container, the reference design specifies it to be filled with a matrix of compacted particulate material (called 'packed particulate'), such as quartz sand granules. The focus of this report is on the mechanical properties of the packed-particulate material, based on information drawn from the extant literature. We first consider the packing density of particulate matrices to minimize the remnant porosity and maximize mechanical stability under conditions of external pressure. Practical methods, involving vibratory packing, are reviewed and recommendations made to select techniques to achieve optimum packing density. The behaviour of particulates under compressive loading has been of interest to the powder metallurgy industry (i.e., the manufacture of products from pressed/sintered metal and ceramic powders) since the early decades of this century. We review the evidence showing that in short timescales, stress induced compaction occurs by particle shuffling and rearrangement, elastic distortion, plastic yielding and microfracturing. Analytical expressions are available to describe these processes in a semiquantitative fashion. Time-dependent compaction, mainly via creep mechanisms, is more complex. Much of the theoretical and experimental information is confined to higher temperatures (> 500 degrees C), where deformation rates are more rapid. Thus, for the relatively low ambient temperatures of the waste container ({approx}100 degrees C), we require analytical techniques to extrapolate the collective particulate creep behaviour. This is largely accomplished by employing current theories of creep deformation, particularly in the form of Deformation Mechanism Maps, which allow estimation of creep rates over a wide

  2. The mechanical behaviour of packed particulates

    International Nuclear Information System (INIS)

    Dutton, R.

    1998-01-01

    Within the Canadian Nuclear Fuel Waste Management program, the central concept is to package used fuel in containers that would be deposited in an underground vault in a plutonic rock formation. To provide internal mechanical support for the container, the reference design specifies it to be filled with a matrix of compacted particulate material (called 'packed particulate'), such as quartz sand granules. The focus of this report is on the mechanical properties of the packed-particulate material, based on information drawn from the extant literature. We first consider the packing density of particulate matrices to minimize the remnant porosity and maximize mechanical stability under conditions of external pressure. Practical methods, involving vibratory packing, are reviewed and recommendations made to select techniques to achieve optimum packing density. The behaviour of particulates under compressive loading has been of interest to the powder metallurgy industry (i.e., the manufacture of products from pressed/sintered metal and ceramic powders) since the early decades of this century. We review the evidence showing that in short timescales, stress induced compaction occurs by particle shuffling and rearrangement, elastic distortion, plastic yielding and microfracturing. Analytical expressions are available to describe these processes in a semiquantitative fashion. Time-dependent compaction, mainly via creep mechanisms, is more complex. Much of the theoretical and experimental information is confined to higher temperatures (> 500 degrees C), where deformation rates are more rapid. Thus, for the relatively low ambient temperatures of the waste container (∼100 degrees C), we require analytical techniques to extrapolate the collective particulate creep behaviour. This is largely accomplished by employing current theories of creep deformation, particularly in the form of Deformation Mechanism Maps, which allow estimation of creep rates over a wide range of stress

  3. A new algorithm for dense ellipse packing and polygonal structures generation in context of FEM or DEM

    Directory of Open Access Journals (Sweden)

    Ilin Dmitrii N.

    2016-01-01

    Full Text Available A new constructive ellipse packing algorithm is presented. It allows to respect the imposed area, shape and spatial orientation distribution (i.e. the inertia tensor and achieve high packing densities. The packing density decreases with increasing particles aspect ratio what is in agreement with results reported in the literature. The generated packings with complex imposed area, shape and spatial orientation distributions with densities in the range of 0.74 and 0.8 are presented. The efficiency of the algorithm is demonstrated by comparison with the Optimized Dropping and Rolling method for disk packing. Moreover, the proposed packing strategy enables to generate very easily non-equiaxed polygonal structures by using Laguerre-Voronoï tessellation of the generated disk-based ellipse packing.

  4. H2 production with low carbon content via MSR in packed bed membrane reactors for high-temperature polymeric electrolyte membrane fuel cell

    International Nuclear Information System (INIS)

    Ribeirinha, P.; Abdollahzadeh, M.; Boaventura, M.; Mendes, A.

    2017-01-01

    Highlights: • H 2 removal diminishes the backward reaction and increases the residence time. • Selective CO 2 removal has low effect on the CH 3 OH conversion compared to H 2 removal. • IL membranes for MSR intents require minimum permeance of ⩾1 × 10 −6 mol s −1 m −2 Pa −1 . • IL-based PBMRs are easier to operate and have low energy consumption. - Abstract: This work compares the hydrogen purity and recovery produced by a methanol steam reforming (MSR) packed bed membrane reactor (PBMR) equipped with a membrane selective to hydrogen (Pd-Ag) and with a membrane selective to carbon dioxide (porous membrane filled with ionic liquids-ILs). A 3-dimensional non-isothermal PBMR model was developed in Fluent (Ansys™) for simulating a PBMR equipped with these two types of membranes and simulating a conventional packed bed reactor (PBR). For the development PBMR models a MSR mechanistic kinetic model was fitted to experimental reaction rates of a commercial catalyst (BASF RP60). The results indicated that selective hydrogen removal from the reaction medium originates a significant increase in the methanol conversion, while the carbon dioxide removal has a smaller effect. CO 2 -PBMR showed to be more efficient in terms of energy consumption than H 2 -PMBR. The simulation results showed also that ILs membranes must have a minimum permeance of ⩾1 x 10 −6 mol s −1 m −2 Pa −1 and CO 2 /H 2 selectivity of ⩾200 at 473 K to be attractive for this type of applications. The advantages and limitations of each reactor configuration are discussed based on experimental and simulated data.

  5. A flow injection analysis system with encapsulated high-density Saccharomyces cerevisiae cells for rapid determination of biochemical oxygen demand.

    Science.gov (United States)

    Seo, Kyo Seong; Choo, Kwang Ho; Chang, Ho Nam; Park, Joong Kon

    2009-05-01

    The biochemical oxygen demand (BOD) determination was studied using a novel flow injection analysis (FIA) system with encapsulated Saccharomyces cerevisiae cells and an oxygen electrode and was compared with conventional 5-day BOD tests. S. cerevisiae cells were packed in a calcium alginate capsule at a dry cell weight of 250 g/l of capsule core. The level of dissolved oxygen (DO) was reduced due to the enhanced respiratory activity of the microbial cells when the injected nutrient passed through the bioreactor. The decrease in DO (DeltaDO) was intensified with the amount of microbial cells packed in the bioreactor. However, the specific DeltaDO decreased as the amount of cells loaded in the bioreactor increased. The DeltaDO value was dependent on the pH and temperature of the mobile phase and reached its maximum value at 35 degrees C and pH 7-8. Also, DeltaDO became larger at longer response times as the flow rate of the mobile phase decreased. The measurement of DeltaDO was repeated more than six times consecutively using a 20-ppm standard glucose and glutamic acid solution, which confirmed the reproducibility with a standard deviation of 0.95%. A strong linear correlation between DeltaDO and BOD was also observed. The 5-day BOD values of actual water and wastewater samples were in accordance with the BOD values obtained by this FIA method using encapsulated S. cerevisiae cells. Unlike the cell-immobilized bead system, there was no contamination of the bioreactor resulting from any leak of yeast cells from the sensor capsules during BOD measurements.

  6. Development of cooling strategy for an air cooled lithium-ion battery pack

    Science.gov (United States)

    Sun, Hongguang; Dixon, Regan

    2014-12-01

    This paper describes a cooling strategy development method for an air cooled battery pack with lithium-ion pouch cells used in a hybrid electric vehicle (HEV). The challenges associated with the temperature uniformity across the battery pack, the temperature uniformity within each individual lithium-ion pouch cell, and the cooling efficiency of the battery pack are addressed. Initially, a three-dimensional battery pack thermal model developed based on simplified electrode theory is correlated to physical test data. An analytical design of experiments (DOE) approach using Optimal Latin-hypercube technique is then developed by incorporating a DOE design model, the correlated battery pack thermal model, and a morphing model. Analytical DOE studies are performed to examine the effects of cooling strategies including geometries of the cooling duct, cooling channel, cooling plate, and corrugation on battery pack thermal behavior and to identify the design concept of an air cooled battery pack to maximize its durability and its driving range.

  7. Domain Discretization and Circle Packings

    DEFF Research Database (Denmark)

    Dias, Kealey

    A circle packing is a configuration of circles which are tangent with one another in a prescribed pattern determined by a combinatorial triangulation, where the configuration fills a planar domain or a two-dimensional surface. The vertices in the triangulation correspond to centers of circles......, and edges correspond to two circles (having centers corresponding to the endpoints of the edge) being tangent to each other. This circle packing creates a rigid structure having an underlying geometric triangulation, where the centers of circles again correspond to vertices in the triangulation......, and the edges are geodesic segments (Euclidean, hyperbolic, or spherical) connecting centers of circles that are tangent to each other. Three circles that are mutually tangent form a face of the triangulation. Since circle packing is closely related to triangulation, circle packing methods can be applied...

  8. Multi-Node Thermal System Model for Lithium-Ion Battery Packs: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Shi, Ying; Smith, Kandler; Wood, Eric; Pesaran, Ahmad

    2015-09-14

    Temperature is one of the main factors that controls the degradation in lithium ion batteries. Accurate knowledge and control of cell temperatures in a pack helps the battery management system (BMS) to maximize cell utilization and ensure pack safety and service life. In a pack with arrays of cells, a cells temperature is not only affected by its own thermal characteristics but also by its neighbors, the cooling system and pack configuration, which increase the noise level and the complexity of cell temperatures prediction. This work proposes to model lithium ion packs thermal behavior using a multi-node thermal network model, which predicts the cell temperatures by zones. The model was parametrized and validated using commercial lithium-ion battery packs. neighbors, the cooling system and pack configuration, which increase the noise level and the complexity of cell temperatures prediction. This work proposes to model lithium ion packs thermal behavior using a multi-node thermal network model, which predicts the cell temperatures by zones. The model was parametrized and validated using commercial lithium-ion battery packs.

  9. Curcumin chemosensitizes 5-fluorouracil resistant MMR-deficient human colon cancer cells in high density cultures.

    Directory of Open Access Journals (Sweden)

    Mehdi Shakibaei

    Full Text Available OBJECTIVE: Treatment of colorectal cancer (CRC remains a clinical challenge, as more than 15% of patients are resistant to 5-Fluorouracil (5-FU-based chemotherapeutic regimens, and tumor recurrence rates can be as high as 50-60%. Cancer stem cells (CSC are capable of surviving conventional chemotherapies that permits regeneration of original tumors. Therefore, we investigated the effectiveness of 5-FU and plant polyphenol (curcumin in context of DNA mismatch repair (MMR status and CSC activity in 3D cultures of CRC cells. METHODS: High density 3D cultures of CRC cell lines HCT116, HCT116+ch3 (complemented with chromosome 3 and their corresponding isogenic 5-FU-chemo-resistant derivative clones (HCT116R, HCT116+ch3R were treated with 5-FU either without or with curcumin in time- and dose-dependent assays. RESULTS: Pre-treatment with curcumin significantly enhanced the effect of 5-FU on HCT116R and HCR116+ch3R cells, in contrast to 5-FU alone as evidenced by increased disintegration of colonospheres, enhanced apoptosis and by inhibiting their growth. Curcumin and/or 5-FU strongly affected MMR-deficient CRC cells in high density cultures, however MMR-proficient CRC cells were more sensitive. These effects of curcumin in enhancing chemosensitivity to 5-FU were further supported by its ability to effectively suppress CSC pools as evidenced by decreased number of CSC marker positive cells, highlighting the suitability of this 3D culture model for evaluating CSC marker expression in a close to vivo setting. CONCLUSION: Our results illustrate novel and previously unrecognized effects of curcumin in enhancing chemosensitization to 5-FU-based chemotherapy on DNA MMR-deficient and their chemo-resistant counterparts by targeting the CSC sub-population. (246 words in abstract.

  10. Curcumin chemosensitizes 5-fluorouracil resistant MMR-deficient human colon cancer cells in high density cultures.

    Science.gov (United States)

    Shakibaei, Mehdi; Buhrmann, Constanze; Kraehe, Patricia; Shayan, Parviz; Lueders, Cora; Goel, Ajay

    2014-01-01

    Treatment of colorectal cancer (CRC) remains a clinical challenge, as more than 15% of patients are resistant to 5-Fluorouracil (5-FU)-based chemotherapeutic regimens, and tumor recurrence rates can be as high as 50-60%. Cancer stem cells (CSC) are capable of surviving conventional chemotherapies that permits regeneration of original tumors. Therefore, we investigated the effectiveness of 5-FU and plant polyphenol (curcumin) in context of DNA mismatch repair (MMR) status and CSC activity in 3D cultures of CRC cells. High density 3D cultures of CRC cell lines HCT116, HCT116+ch3 (complemented with chromosome 3) and their corresponding isogenic 5-FU-chemo-resistant derivative clones (HCT116R, HCT116+ch3R) were treated with 5-FU either without or with curcumin in time- and dose-dependent assays. Pre-treatment with curcumin significantly enhanced the effect of 5-FU on HCT116R and HCR116+ch3R cells, in contrast to 5-FU alone as evidenced by increased disintegration of colonospheres, enhanced apoptosis and by inhibiting their growth. Curcumin and/or 5-FU strongly affected MMR-deficient CRC cells in high density cultures, however MMR-proficient CRC cells were more sensitive. These effects of curcumin in enhancing chemosensitivity to 5-FU were further supported by its ability to effectively suppress CSC pools as evidenced by decreased number of CSC marker positive cells, highlighting the suitability of this 3D culture model for evaluating CSC marker expression in a close to vivo setting. Our results illustrate novel and previously unrecognized effects of curcumin in enhancing chemosensitization to 5-FU-based chemotherapy on DNA MMR-deficient and their chemo-resistant counterparts by targeting the CSC sub-population. (246 words in abstract).

  11. High Cell Density Upregulates Calcium Oscillation by Increasing Calcium Store Content via Basal Mitogen-Activated Protein Kinase Activity.

    Directory of Open Access Journals (Sweden)

    Mitsuhiro Morita

    Full Text Available Calcium releases of non-excitable cells are generally a combination of oscillatory and non-oscillatory patterns, and factors affecting the calcium dynamics are still to be determined. Here we report the influence of cell density on calcium increase patterns of clonal cell lines. The majority of HeLa cells seeded at 1.5 x 104/cm2 showed calcium oscillations in response to histamine and ATP, whereas cells seeded at 0.5 x 104/cm2 largely showed transient and sustained calcium increases. Cell density also affected the response of HEK293 cells to ATP in a similar manner. High cell density increased the basal activity of the mitogen-activated protein (MAP kinase and calcium store content, and both calcium oscillation and calcium store content were down-regulated by a MAP kinase inhibitor, U0126. Thus, MAP kinase-mediated regulation of calcium store likely underlie the effect of cell density on calcium oscillation. Calcium increase patterns of HeLa cells were conserved at any histamine concentrations tested, whereas the overexpression of histamine H1 receptor, which robustly increased histamine-induced inositol phospholipid hydrolysis, converted calcium oscillations to sustained calcium increases only at high histamine concentrations. Thus, the consequence of modulating inositol phospholipid metabolism was distinct from that of changing cell density, suggesting the effect of cell density is not attributed to inositol phospholipid metabolism. Collectively, our results propose that calcium increase patterns of non-excitable cells reflect calcium store, which is regulated by the basal MAP kinase activity under the influence of cell density.

  12. Hydroxysafflor yellow A suppresses oxidized low density lipoprotein induced proliferation of vascular smooth muscle cells

    Directory of Open Access Journals (Sweden)

    Lin Sheng

    2012-06-01

    Full Text Available To investigate the relationship between the suppression of Hydroxysafflor yellow A (HSYA on the oxidized low density lipoprotein (ox-LDL induced proliferation of vascular smooth muscle cells (VSMCs and the mRNA and protein expression of extracellular signal-regulated protein kinase 1/2 (ERK1/2 and mitogen activated protein kinase phospholipase-1 (MAKP-1, VSMCs were treated with HSYA at 10 ?mol/L and/or ox-LDL at 35 mg/L for 48 h. MTT assay was done to measure cell survival rate, flow cytometry to detect cell cycle, reverse transcription PCR and Western blot to detect the expression of ERK1/2 and MAKP-1. When compared to cells treated with ox-LDL alone, the survival rate of cells treated with two reagents was reduced and the proportion of cells in G0/G1 phase significantly increased, with increased MKP-1 expression. The study suggests HSYA can inhibit VSMC proliferation via increasing MKP-1 expression, reducing p-ERK1/2 activity and suppressing cell cycle.

  13. Development of silver-zinc cells of improved cycle life and energy density

    Science.gov (United States)

    Serenyi, Roberto; James, Stanley D.

    1994-03-01

    Substantial increases in the cost effectiveness and range of naval underwater vehicles are possible by virtue of advances made, in this program, to silver-zinc, vehicle propulsion batteries. To improve battery cycle life and energy density, electropermeable membranes (EPM's) were used as additives and/or as coatings for the negative electrodes and as coatings for conventional separator materials. Also, bismuth oxide was tested as an additive to the negative electrodes and P2291-40/20, a radiation-grafted polyethylene film, as a separator used in conjunction with silver-treated cellophane. EPM's used as negative electrode additives and also as coatings for Celgard 2500 microporous polypropylene greatly improved cells. Cells with EPM's used as coatings for the negative electrodes failed rapidly because of an error in formulation. Cells with 10 percent bismuth oxide in the negative electrodes exhibited substantially lower capacity than the standard cells and were removed from the test. Cells with radiation-grafted polyethylene separators provided fewer cycles than the standard cells, with 5 percent higher capacity and 6 percent lower utilization of active materials by cycle 60. However, the slightly better capacity of these cells, realized due to the additional space available for active materials, does not compensate for their generally unimpressive performance.

  14. Current Density Distribution Mapping in PEM Fuel Cells as An Instrument for Operational Measurements

    Directory of Open Access Journals (Sweden)

    Martin Geske

    2010-04-01

    Full Text Available A newly developed measurement system for current density distribution mapping has enabled a new approach for operational measurements in proton exchange membrane fuel cells (PEMFC. Taking into account previously constructed measurement systems, a method based on a multi layer printed circuit board was chosen for the development of the new system. This type of system consists of a sensor, a special electronic device and the control and visualization PC. For the acquisition of the current density distribution values, a sensor device was designed and installed within a multilayer printed circuit board with integrated shunt resistors. Varying shunt values can be taken into consideration with a newly developed and evaluated calibration method. The sensor device was integrated in a PEM fuel cell stack to prove the functionality of the whole measurement system. A software application was implemented to visualize and save the measurement values. Its functionality was verified by operational measurements within a PEMFC system. Measurement accuracy and possible negative reactions of the sensor device during PEMFC operation are discussed in detail in this paper. The developed system enables operational measurements for different operating phases of PEM fuel cells. Additionally, this can be seen as a basis for new opportunities of optimization for fuel cell design and operation modes.

  15. Noninvasive prenatal diagnosis. Use of density gradient centrifugation, magnetically activated cell sorting and in situ hybridization.

    Science.gov (United States)

    Campagnoli, C; Multhaupt, H A; Ludomirski, A; Haut, M J; Warhol, M J

    1997-04-01

    To develop a noninvasive method suitable for clinical prenatal diagnosis. Fetal nucleated erythrocytes were separated from peripheral blood of 17 healthy pregnant women using small magnetically activated cell sorting columns (MiniMACS) following density gradient centrifugation and dual antibody labeling methods. The protocol was designed to compare the efficacy of antitransferrin receptor (CD71)/antiglycophorin A (GPA) antibodies with antithrom-bospondin receptor (CD36)/anti-GPA antibodies in identifying nucleated erythrocytes in maternal blood. Cytospin preparations of the isolated cells were subjected to in situ hybridization with specific DNA probes for the Y chromosome and chromosome 21 to confirm the fetal origin. After MiniMACS the enrichment factors for the CD71/GPA- and CD36/GPA-positive cells from maternal blood were similar, and the percentages of fetal cells recovered did not differ. Seven of seven male pregnancies were correctly identified. One case of trisomy 21 was detected. The in situ hybridization analysis of fetal nucleated erythrocytes isolated from maternal blood using single density gradient centrifugation, anti-CD71/anti-GPA immunostaining and MiniMACS could be an accurate, sensitive and noninvasive method for prenatal diagnosis.

  16. Effects of Electromagnetic Stimulation on Cell Density and Neural Markers in Murine Enteric Cell Cultures

    International Nuclear Information System (INIS)

    Carreon-Rodriguez, A.; Belkind-Gerson, J.; Serrano-Luna, G.; Canedo-Dorantes, L.

    2008-01-01

    Availability of adult stem cells from several organs like bone marrow, umbilical cord blood or peripheral blood has become a powerful therapeutic tool for many chronic diseases. Potential of adult stem cells for regeneration extents to other tissues among them the nervous system. However two obstacles should be resolved before such cells could be currently applied in clinical practice: a) slow growth rate and b) ability to form enough dense colonies in order to populate a specific injury or cellular deficiency. Many approaches have been explored as genetic differentiation programs, growth factors, and supplemented culture media, among others. Electromagnetic field stimulation of differentiation, proliferation, migration, and particularly on neurogenesis is little known. Since the biological effects of ELF-EMF are well documented, we hypothesize ELF-EMF could affect growth and maturation of stem cells derived of enteric tissue

  17. Plasma membrane temperature gradients and multiple cell permeabilization induced by low peak power density femtosecond lasers

    Directory of Open Access Journals (Sweden)

    Allen L. Garner

    2016-03-01

    Full Text Available Calculations indicate that selectively heating the extracellular media induces membrane temperature gradients that combine with electric fields and a temperature-induced reduction in the electropermeabilization threshold to potentially facilitate exogenous molecular delivery. Experiments by a wide-field, pulsed femtosecond laser with peak power density far below typical single cell optical delivery systems confirmed this hypothesis. Operating this laser in continuous wave mode at the same average power permeabilized many fewer cells, suggesting that bulk heating alone is insufficient and temperature gradients are crucial for permeabilization. This work suggests promising opportunities for a high throughput, low cost, contactless method for laser mediated exogenous molecule delivery without the complex optics of typical single cell optoinjection, for potential integration into microscope imaging and microfluidic systems.

  18. Enhanced photocurrent density of HTM-free perovskite solar cells by carbon quantum dots

    Science.gov (United States)

    Zou, Haiyuan; Guo, Daipeng; He, Bowen; Yu, Jiaguo; Fan, Ke

    2018-02-01

    Full-printable and hole transport material (HTM)-free perovskite solar cells (PSCs) with carbon counter electrodes feature high stability and low cost. However, the perovskite film prepared by conventional one-step solution-coating method always shows a relatively poor coverage on the substrate, leading to the limit of the photocurrent density. In this study, we incorporated carbon quantum dots (CQDs) in the perovskite films, and investigated their effects on the performance of TiO2 nanosheet-based and HTM-free PSCs. It was found that the addition of CQDs to the perovskite film can enhance the photocurrent density of PSCs, and the optimal PSC with 0.1% CQDs evolved 60% higher photocurrent density than the pristine one. The improved photocurrent density was attributed to the heterogeneous nuclei derived from CQDs during perovskite crystallization, which would increase amount of perovskite nuclei and form a fine perovskite grain, leading to a better coverage on the substrate. Moreover, due to the excellent conductivity, CQDs in perovskite films could efficiently transport the photo-excited electrons, accelerating the separation and mobilization of charge carriers. This study presents the incorporation of CQDs in perovskite as an efficient approach to promote the performance of HTM-free PSCs.

  19. Estimating the neutrally buoyant energy density of a Rankine-cycle/fuel-cell underwater propulsion system

    Science.gov (United States)

    Waters, Daniel F.; Cadou, Christopher P.

    2014-02-01

    A unique requirement of underwater vehicles' power/energy systems is that they remain neutrally buoyant over the course of a mission. Previous work published in the Journal of Power Sources reported gross as opposed to neutrally-buoyant energy densities of an integrated solid oxide fuel cell/Rankine-cycle based power system based on the exothermic reaction of aluminum with seawater. This paper corrects this shortcoming by presenting a model for estimating system mass and using it to update the key findings of the original paper in the context of the neutral buoyancy requirement. It also presents an expanded sensitivity analysis to illustrate the influence of various design and modeling assumptions. While energy density is very sensitive to turbine efficiency (sensitivity coefficient in excess of 0.60), it is relatively insensitive to all other major design parameters (sensitivity coefficients < 0.15) like compressor efficiency, inlet water temperature, scaling methodology, etc. The neutral buoyancy requirement introduces a significant (∼15%) energy density penalty but overall the system still appears to offer factors of five to eight improvements in energy density (i.e., vehicle range/endurance) over present battery-based technologies.

  20. Use of Phytone Peptone to Optimize Growth and Cell Density of Lactobacillus reuteri

    Directory of Open Access Journals (Sweden)

    Olabiyi A. Atilola

    2015-08-01

    Full Text Available The objective of this study was to determine the use of phytone peptone to optimize the growth and cell density of Lactobacillus reuteri. Four strains of L. reuteri (DSM 20016, SD 2112, CF 2-7F, and MF 2-3, were used in this study. An overnight culture of individual strains was inoculated into fresh basal media with various protein sources (peptone, tryptone, proteose peptone #3, phytone peptone, tryptic soy broth, yeast extract, and beef extract. Samples were then mixed well and incubated at 37 °C for 15 h. Bacterial growth was monitored by measuring turbidity (optical density 610 nm at different time intervals during the incubation period. At the end of incubation, samples were plated on de-Man Rogosa Sharpe (MRS agar to determine the bacterial population. Our results showed that phytone peptone promoted the growth of L. reuteri (p < 0.05 by 1.4 log CFU/mL on average compared to the control samples. Therefore, phytone peptone could be included in laboratory media to enhance growth and increase the cell density of L. reuteri.

  1. Low density of membrane particles in auditory hair cells of lizards and birds suggests an absence of somatic motility.

    Science.gov (United States)

    Köppl, Christine; Forge, Andrew; Manley, Geoffrey A

    2004-11-08

    Hair cells are the mechanoreceptive cells of the vertebrate lateral line and inner ear. In addition to their sensory function, hair cells display motility and thus themselves generate mechanical energy, which is thought to enhance sensitivity. Two principal cellular mechanism are known that can mediate hair-cell motility in vitro. One of these is based on voltage-dependent changes of an intramembrane protein and has so far been demonstrated only in outer hair cells of the mammalian cochlea. Correlated with this, the cell membranes of outer hair cells carry an extreme density of embedded particles, as revealed by freeze fracturing. The present study explored the possibility of membrane-based motility in hair cells of nonmammals, by determining their density of intramembrane particles. Replicas of freeze-fractured membrane were prepared from auditory hair cells of a lizard, the Tokay gecko, and a bird, the barn owl. These species were chosen because of independent evidence for active cochlear mechanics, in the form of spontaneous otoacoustic emissions. For quantitative comparison, mammalian inner and outer hair cells, as well as vestibular hair, cells were reevaluated. Lizard and bird hair cells displayed median densities of 2,360 and 1,880 intramembrane particles/microm2, respectively. This was not significantly different from the densities in vestibular and mammalian inner hair cells; however, it was about half the density in of mammalian outer hair cells. This suggests that nonmammalian hair cells do not possess high densities of motor protein in their membranes and are thus unlikely to be capable of somatic motility. 2004 Wiley-Liss, Inc.

  2. Mast cell density and angiogenesis in oral dysplastic epithelium and low- and high-grade oral squamous cell carcinoma.

    Science.gov (United States)

    Mohtasham, Nooshin; Babakoohi, Shahab; Salehinejad, Jahanshah; Montaser-Kouhsari, Laleh; Shakeri, Mohammad Taghi; Shojaee, Setareh; Sistani, Noorieh Sharifi; Firooz, Alireza

    2010-09-01

    Oral squamous cell carcinoma (OSCC) is one of the 10 most common malignant tumors and SCC accounts for approximately 94% of all oral malignancies. The risk of malignant transformation in dysplastic lesions is greater than that of normal oral mucosa. The definite roles of mast cells and angiogenesis in OSCC have been under debate. The aim of this study was to compare mast cell count (MCC) and microvessel density (MVD) among normal oral mucosa, oral dysplastic epithelium and low- and high- grade OSCC. A total of 42 specimens of OSCC (21 high- and 21 low-grade) were collected, along with six normal and 22 dysplastic oral mucosa. The mean MCC and MVD, as well as the correlation between them, were evaluated by immunohistochemical staining. Statistically significant increases in mean MCC and MVD were observed between normal oral mucosa and epithelial dysplasia, normal oral mucosa and OSCC and epithelial dysplasia and OSCC (P epithelial dysplasia.

  3. Cellulose Structural Polymorphism in Plant Primary Cell Walls Investigated by High-Field 2D Solid-State NMR Spectroscopy and Density Functional Theory Calculations.

    Science.gov (United States)

    Wang, Tuo; Yang, Hui; Kubicki, James D; Hong, Mei

    2016-06-13

    The native cellulose of bacterial, algal, and animal origins has been well studied structurally using X-ray and neutron diffraction and solid-state NMR spectroscopy, and is known to consist of varying proportions of two allomorphs, Iα and Iβ, which differ in hydrogen bonding, chain packing, and local conformation. In comparison, cellulose structure in plant primary cell walls is much less understood because plant cellulose has lower crystallinity and extensive interactions with matrix polysaccharides. Here we have combined two-dimensional magic-angle-spinning (MAS) solid-state nuclear magnetic resonance (solid-state NMR) spectroscopy at high magnetic fields with density functional theory (DFT) calculations to obtain detailed information about the structural polymorphism and spatial distributions of plant primary-wall cellulose. 2D (13)C-(13)C correlation spectra of uniformly (13)C-labeled cell walls of several model plants resolved seven sets of cellulose chemical shifts. Among these, five sets (denoted a-e) belong to cellulose in the interior of the microfibril while two sets (f and g) can be assigned to surface cellulose. Importantly, most of the interior cellulose (13)C chemical shifts differ significantly from the (13)C chemical shifts of the Iα and Iβ allomorphs, indicating that plant primary-wall cellulose has different conformations, packing, and hydrogen bonding from celluloses of other organisms. 2D (13)C-(13)C correlation experiments with long mixing times and with water polarization transfer revealed the spatial distributions and matrix-polysaccharide interactions of these cellulose structures. Celluloses f and g are well mixed chains on the microfibril surface, celluloses a and b are interior chains that are in molecular contact with the surface chains, while cellulose c resides in the core of the microfibril, outside spin diffusion contact with the surface. Interestingly, cellulose d, whose chemical shifts differ most significantly from those of

  4. Analysis of electronic models for solar cells including energy resolved defect densities

    Energy Technology Data Exchange (ETDEWEB)

    Glitzky, Annegret

    2010-07-01

    We introduce an electronic model for solar cells including energy resolved defect densities. The resulting drift-diffusion model corresponds to a generalized van Roosbroeck system with additional source terms coupled with ODEs containing space and energy as parameters for all defect densities. The system has to be considered in heterostructures and with mixed boundary conditions from device simulation. We give a weak formulation of the problem. If the boundary data and the sources are compatible with thermodynamic equilibrium the free energy along solutions decays monotonously. In other cases it may be increasing, but we estimate its growth. We establish boundedness and uniqueness results and prove the existence of a weak solution. This is done by considering a regularized problem, showing its solvability and the boundedness of its solutions independent of the regularization level. (orig.)

  5. Use of Phytone Peptone to Optimize Growth and Cell Density of Lactobacillus reuteri.

    Science.gov (United States)

    Atilola, Olabiyi A; Gyawali, Rabin; Aljaloud, Sulaiman O; Ibrahim, Salam A

    2015-08-10

    The objective of this study was to determine the use of phytone peptone to optimize the growth and cell density of Lactobacillus reuteri. Four strains of L. reuteri (DSM 20016, SD 2112, CF 2-7F, and MF 2-3,) were used in this study. An overnight culture of individual strains was inoculated into fresh basal media with various protein sources (peptone, tryptone, proteose peptone #3, phytone peptone, tryptic soy broth, yeast extract, and beef extract). Samples were then mixed well and incubated at 37 °C for 15 h. Bacterial growth was monitored by measuring turbidity (optical density 610 nm) at different time intervals during the incubation period. At the end of incubation, samples were plated on de-Man Rogosa Sharpe (MRS) agar to determine the bacterial population. Our results showed that phytone peptone promoted the growth of L. reuteri ( p reuteri .

  6. Modeling quorum sensing trade-offs between bacterial cell density and system extension from open boundaries

    Science.gov (United States)

    Marenda, Mattia; Zanardo, Marina; Trovato, Antonio; Seno, Flavio; Squartini, Andrea

    2016-12-01

    Bacterial communities undergo collective behavioural switches upon producing and sensing diffusible signal molecules; a mechanism referred to as Quorum Sensing (QS). Exemplarily, biofilm organic matrices are built concertedly by bacteria in several environments. QS scope in bacterial ecology has been debated for over 20 years. Different perspectives counterpose the role of density reporter for populations to that of local environment diffusivity probe for individual cells. Here we devise a model system where tubes of different heights contain matrix-embedded producers and sensors. These tubes allow non-limiting signal diffusion from one open end, thereby showing that population spatial extension away from an open boundary can be a main critical factor in QS. Experimental data, successfully recapitulated by a comprehensive mathematical model, demonstrate how tube height can overtake the role of producer density in triggering sensor activation. The biotic degradation of the signal is found to play a major role and to be species-specific and entirely feedback-independent.

  7. Absolute Density Calibration Cell for Laser Induced Fluorescence Erosion Rate Measurements

    Science.gov (United States)

    Domonkos, Matthew T.; Stevens, Richard E.

    2001-01-01

    Flight qualification of ion thrusters typically requires testing on the order of 10,000 hours. Extensive knowledge of wear mechanisms and rates is necessary to establish design confidence prior to long duration tests. Consequently, real-time erosion rate measurements offer the potential both to reduce development costs and to enhance knowledge of the dependency of component wear on operating conditions. Several previous studies have used laser-induced fluorescence (LIF) to measure real-time, in situ erosion rates of ion thruster accelerator grids. Those studies provided only relative measurements of the erosion rate. In the present investigation, a molybdenum tube was resistively heated such that the evaporation rate yielded densities within the tube on the order of those expected from accelerator grid erosion. This work examines the suitability of the density cell as an absolute calibration source for LIF measurements, and the intrinsic error was evaluated.

  8. Distribution of the Current Density in Electrolyte of the Pem Fuel Cell

    Directory of Open Access Journals (Sweden)

    Eugeniusz Kurgan

    2004-01-01

    Full Text Available In this paper water management in proton exchange membrane (PEM fuel cell is considered. Firt mass convervation law for water is applied. Next proton transport is described by the Nernst-Planck equation and liqid water convection velocity is eliminated by the Schlogl equation. Electro-osmotic drag coefficient is related to hydrogen index and experimentally determined swelling coefficient. Three partial differential equations for molar water concentration Cw, electric potential ϕ and water pressure Pw are formulated. Current density vector i is derived from proton flux expression. These equations together with adequate boundary conditions were solved using finite element method. The distribution of electric potential and current density in function of geometrical parametres is investigated. At the end some illustrative example is given.

  9. Quorum sensing integrates environmental cues, cell density and cell history to control bacterial competence

    NARCIS (Netherlands)

    Moreno-Gámez, Stefany; Sorg, Robin A; Domenech, Arnau; Kjos, Morten; Weissing, Franz J; van Doorn, G Sander; Veening, Jan-Willem

    2017-01-01

    Streptococcus pneumoniae becomes competent for genetic transformation when exposed to an autoinducer peptide known as competence-stimulating peptide (CSP). This peptide was originally described as a quorum-sensing signal, enabling individual cells to regulate competence in response to population

  10. Hardness of approximation for strip packing

    DEFF Research Database (Denmark)

    Adamaszek, Anna Maria; Kociumaka, Tomasz; Pilipczuk, Marcin

    2017-01-01

    Strip packing is a classical packing problem, where the goal is to pack a set of rectangular objects into a strip of a given width, while minimizing the total height of the packing. The problem has multiple applications, for example, in scheduling and stock-cutting, and has been studied extensive...

  11. Simulation of lithium ion battery replacement in a battery pack for application in electric vehicles

    Science.gov (United States)

    Mathew, M.; Kong, Q. H.; McGrory, J.; Fowler, M.

    2017-05-01

    The design and optimization of the battery pack in an electric vehicle (EV) is essential for continued integration of EVs into the global market. Reconfigurable battery packs are of significant interest lately as they allow for damaged cells to be removed from the circuit, limiting their impact on the entire pack. This paper provides a simulation framework that models a battery pack and examines the effect of replacing damaged cells with new ones. The cells within the battery pack vary stochastically and the performance of the entire pack is evaluated under different conditions. The results show that by changing out cells in the battery pack, the state of health of the pack can be consistently maintained above a certain threshold value selected by the user. In situations where the cells are checked for replacement at discrete intervals, referred to as maintenance event intervals, it is found that the length of the interval is dependent on the mean time to failure of the individual cells. The simulation framework as well as the results from this paper can be utilized to better optimize lithium ion battery pack design in EVs and make long term deployment of EVs more economically feasible.

  12. Modeling the short-circuit current density of polymer solar cells based on P3HT:PCBM blend

    Energy Technology Data Exchange (ETDEWEB)

    Monestier, Florent; Simon, Jean-Jacques; Torchio, Philippe; Escoubas, Ludovic; Flory, Francois [Institut FRESNEL, UMR-CNRS 6133, Domaine Universitaire de St-Jerome, 13397 Marseille Cedex 20 (France); Bailly, Sandrine; de Bettignies, Remi; Guillerez, Stephane [INES CEA/DRT/LITEN/DTS/LCS, BP 332 50, av. du lac Leman 73370, Le Bourget du lac (France); Defranoux, Christophe [SOPRA-SA, Bois Colombes (France)

    2007-03-06

    We have investigated the short-circuit current density of organic solar cells based on poly (3-hexylthiophene)(P3HT)/6,6-phenyl C61-butyric acid methyl ester (PCBM) blend. In order to model charge collection efficiencies with respect to short circuit density in such blends, a full optical modeling of the cell is performed. From the distribution of the electromagnetic field, we compute the rate of exciton generation. This exciton generation rate is used as input in the transport equations of holes and electrons. Charge densities at steady state are obtained as solutions are used for computing short-circuit current densities generated in the cell. The dependence of short-circuit current densities versus the thickness of the blend is analyzed and compared with our experimental data and with data extracted from the literature. (author)

  13. Suitable housekeeping genes for normalization of transcript abundance analysis by real-time RT-PCR in cultured bovine granulosa cells during hypoxia and differential cell plating density.

    Science.gov (United States)

    Baddela, Vijay S; Baufeld, Anja; Yenuganti, Vengala R; Vanselow, Jens; Singh, Dheer

    2014-11-27

    Bovine granulosa cell culture models are important to understand molecular mechanisms of ovarian function. Folliculogenesis and luteinization are associated with increasing density of cells and local hypoxic conditions. The current study identified two reliable housekeeping genes useful for gene normalization in granulosa cells under different in vitro conditions. During the current experiments cells were subjected to different biological and physical stimuli, follicle stimulating hormone, different initial cell plating density and hypoxia. Transcript abundance of seven housekeeping genes was quantified by real-time RT-PCR with co-amplification of the respective external standard. Three of the genes, GAPDH, HMBS, and HPRT1 were found to be regulated by initial cell plating density, five of them, GAPDH, HMBS, HPRT1, RPLP0 and RPS18 under hypoxic conditions, but none of them after FSH stimulation. In detail, GAPDH was up regulated, but HPRT1 and HMBS were down regulated at high density and under hypoxia. Expression of RPLP0 and RPS18 was inconsistent, but was significantly down-regulated in particular at high cell density combined with hypoxia. In contrast, TBP and B2M genes were neither regulated under different plating density conditions nor by hypoxia as they showed similar expression levels under all conditions analyzed. The present data indicate that TBP and B2M are appropriate housekeeping genes for normalization of transcript abundance measured by real-time RT-PCR in granulosa cells subjected to different plating densities, oxygen concentrations and FSH stimulation.

  14. Comparison of manual & automated analysis methods for corneal endothelial cell density measurements by specular microscopy.

    Science.gov (United States)

    Huang, Jianyan; Maram, Jyotsna; Tepelus, Tudor C; Modak, Cristina; Marion, Ken; Sadda, SriniVas R; Chopra, Vikas; Lee, Olivia L

    2017-08-07

    To determine the reliability of corneal endothelial cell density (ECD) obtained by automated specular microscopy versus that of validated manual methods and factors that predict such reliability. Sharp central images from 94 control and 106 glaucomatous eyes were captured with Konan specular microscope NSP-9900. All images were analyzed by trained graders using Konan CellChek Software, employing the fully- and semi-automated methods as well as Center Method. Images with low cell count (input cells number <100) and/or guttata were compared with the Center and Flex-Center Methods. ECDs were compared and absolute error was used to assess variation. The effect on ECD of age, cell count, cell size, and cell size variation was evaluated. No significant difference was observed between the Center and Flex-Center Methods in corneas with guttata (p=0.48) or low ECD (p=0.11). No difference (p=0.32) was observed in ECD of normal controls <40 yrs old between the fully-automated method and manual Center Method. However, in older controls and glaucomatous eyes, ECD was overestimated by the fully-automated method (p=0.034) and semi-automated method (p=0.025) as compared to manual method. Our findings show that automated analysis significantly overestimates ECD in the eyes with high polymegathism and/or large cell size, compared to the manual method. Therefore, we discourage reliance upon the fully-automated method alone to perform specular microscopy analysis, particularly if an accurate ECD value is imperative. Copyright © 2017. Published by Elsevier España, S.L.U.

  15. Noninvasive prenatal diagnosis. Use of density gradient centrifugation, magnetically activated cell sorting and in situ hybridization

    DEFF Research Database (Denmark)

    Campagnoli, C; Multhaupt, H A; Ludomirski, A

    1997-01-01

    centrifugation and dual antibody labeling methods. The protocol was designed to compare the efficacy of antitransferrin receptor (CD71)/antiglycophorin A (GPA) antibodies with antithrom-bospondin receptor (CD36)/anti-GPA antibodies in identifying nucleated erythrocytes in maternal blood. Cytospin preparations...... cells recovered did not differ. Seven of seven male pregnancies were correctly identified. One case of trisomy 21 was detected. CONCLUSION: The in situ hybridization analysis of fetal nucleated erythrocytes isolated from maternal blood using single density gradient centrifugation, anti-CD71/anti...

  16. Deterministic indexing for packed strings

    DEFF Research Database (Denmark)

    Bille, Philip; Gørtz, Inge Li; Skjoldjensen, Frederik Rye

    2017-01-01

    Given a string S of length n, the classic string indexing problem is to preprocess S into a compact data structure that supports efficient subsequent pattern queries. In the deterministic variant the goal is to solve the string indexing problem without any randomization (at preprocessing time...... or query time). In the packed variant the strings are stored with several character in a single word, giving us the opportunity to read multiple characters simultaneously. Our main result is a new string index in the deterministic and packed setting. Given a packed string S of length n over an alphabet σ......, we show how to preprocess S in O(n) (deterministic) time and space O(n) such that given a packed pattern string of length m we can support queries in (deterministic) time O (m/α + log m + log log σ), where α = w/log σ is the number of characters packed in a word of size w = θ(log n). Our query time...

  17. Role of low density lipoprotein-bound cholesterol esters in acute lymphoblastic leukemia cells

    International Nuclear Information System (INIS)

    Cutts, J.L.; Madden, E.A.; Melnykovych, G.

    1986-01-01

    The glucocorticoid sensitive CEM-C7 T-cell line was derived from human acute lymphoblastic leukemia cells by Norman and Thompson. Madden et al. have demonstrated that this growth inhibitory effect is due in part to a glucocorticoid-mediated inhibition of cholesterol synthesis and can be partially reversed by cholesterol dispersions. To further delineate the role of cholesterol in this growth inhibition, they have examined the ability of low density lipoprotein (LDL)-bound [ 3 H]cholesterol linoleate to reverse the growth inhibitory effect of 1 μM dexamethasone (Dex) on the CEM-C7 cells. LDL-bound cholesterol linoleate was unable to reverse the Dex-mediated growth inhibition, although incorporation of [ 14 C] acetate into free cholesterol was inhibited by 29%, following the Brown and Goldstein model. The presence of Dex further inhibited acetate incorporation into free cholesterol in the LDL-treated cells. Under all conditions, more than 99% of the acetate incorporated into cholesterol was present as free cholesterol, while over 87% of the LDL-bound cholesterol linoleate taken up remained in the ester compartment. These results indicate that CEM-C7 cells are unable to utilize LDL-bound cholesterol esters as a source of free cholesterol and rely on endogenous synthesis for their free cholesterol requirements

  18. Regulation of low density lipoprotein receptor function in a human hepatoma cell line

    International Nuclear Information System (INIS)

    Leichtner, A.M.; Krieger, M.; Schwartz, A.L.

    1984-01-01

    Low density lipoprotein (LDL) processing was investigated in a human hepatoma-derived cell line, Hep G2. Hep G2 cells bound, internalized and degraded LDL via a saturable, high affinity pathway similar to that present in other mammalian cells. Although 80% of the uptake and degradation of 125 I-LDL was inhibited by 40-fold excess native LDL, the same concentration of methylated LDL, which cannot bind to LDL receptors, had virtually no effect on processing. When added at low concentrations, the lysosomotropic agent, chloroquine, inhibited degradation without affecting the rate of lipoprotein internalization. Receptor activity was decreased 60% by preincubation of the cells in medium containing a source of cholesterol (LDL or unesterified cholesterol) and increased 1.7-fold by preincubation with compactin, a competitive inhibitor of 3-hydroxy-3-methylglutaryl coenzyme A reductase. The Hep G2 cell line may prove a useful system both for the further study of hepatic lipoprotein metabolism and for the evaluation of new antihypercholesterolemic agents

  19. Dissecting the actin cortex density and membrane-cortex distance in living cells by super-resolution microscopy

    DEFF Research Database (Denmark)

    Clausen, M. P.; Colin-York, H.; Schneider, Falk

    2017-01-01

    and accurately measure the density distribution of the cortical actin cytoskeleton and the distance between the actin cortex and the membrane in live Jurkat T-cells. We found an asymmetric cortical actin density distribution with a mean width of 230 (+105/-125) nm. The spatial distances measured between...

  20. Fast wave experiments in LAPD: RF sheaths, convective cells and density modifications

    Science.gov (United States)

    Carter, T. A.; van Compernolle, B.; Martin, M.; Gekelman, W.; Pribyl, P.; van Eester, D.; Crombe, K.; Perkins, R.; Lau, C.; Martin, E.; Caughman, J.; Tripathi, S. K. P.; Vincena, S.

    2017-10-01

    An overview is presented of recent work on ICRF physics at the Large Plasma Device (LAPD) at UCLA. The LAPD has typical plasma parameters ne 1012 -1013 cm-3, Te 1 - 10 eV and B 1000 G. A new high-power ( 150 kW) RF system and fast wave antenna have been developed for LAPD. The source runs at a frequency of 2.4 MHz, corresponding to 1 - 7fci , depending on plasma parameters. Evidence of rectified RF sheaths is seen in large increases ( 10Te) in the plasma potential on field lines connected to the antenna. The rectified potential scales linearly with antenna current. The rectified RF sheaths set up convective cells of local E × B flows, measured indirectly by potential measurements, and measured directly with Mach probes. At high antenna powers substantial modifications of the density profile were observed. The plasma density profile initially exhibits transient low frequency oscillations (10 kHz). The amplitude of the fast wave fields in the core plasma is modulated at the same low frequency, suggesting fast wave coupling is affected by the density rearrangement. Work performed at the Basic Plasma Science Facility, supported jointly by the National Science Foundation and the Department of Energy.

  1. Reconstructing Solvent Density of Myoglobin Unit Cell from Proximal Radial Distribution Functions of Amino Acids

    Science.gov (United States)

    Galbraith, Madeline; Lynch, Gc; Pettitt, Bm

    Understanding the solvent density around a protein crystal structure is an important step for refining accurate crystal structures for use in dynamics simulations or in free energy calculations. The free energy of solvation has typically been approximated using an implicit continuum solvent model or an all atom MD simulation, with a trade-off between accuracy and computation time. For proteins, using precomputed proximal radial distribution functions (pRDFs) of the solvent to reconstruct solvent density on a grid is much faster than all atom MD simulations and more accurate than using implicit solvent models. MD simulations were run for the 20 common amino acids and pRDFs were calculated for several atom type data sets with and without hydrogens, using atom types representative of amino acid side chain atoms. Preliminary results from reconstructions suggest using a data set with 15 heavy atoms and 3 hydrogen yields results with the lowest error without a tradeoff on time. The results of using precomputed pRDFs to reconstruct the solvent density of water for the myoglobin (pdb ID 2mgk) unit cell quantifies the accuracy of the method in comparison with the crystallographic data. Funding Acknowledgement: This research was funded by the CPRIT Summer Undergraduate Program in Computational Cancer Biology, training Grant award RP 140113 from the Cancer Prevention & Research Institute of Texas (CPRIT).

  2. High power-density single-chamber fuel cells operated on methane

    Science.gov (United States)

    Shao, Zongping; Mederos, Jennifer; Chueh, William C.; Haile, Sossina. M.

    Single-chamber solid oxide fuel cells (SC-SOFCs) incorporating thin-film Sm 0.15Ce 0.85O 1.925 (SDC) as the electrolyte, thick Ni + SDC as the (supporting) anode and SDC + BSCF (Ba 0.5Sr 0.5Co 0.8Fe 0.2O 3- δ) as the cathode were operated in a mixture of methane, oxygen and helium at furnace temperatures of 500-650 °C. Because of the exothermic nature of the oxidation reactions that occur at the anode, the cell temperature was as much as 150 °C greater than the furnace temperature. Overall, the open circuit voltage was only slightly sensitive to temperature and gas composition, varying from ∼0.70 to ∼0.78 V over the range of conditions explored. In contrast, the power density strongly increased with temperature and broadly peaked at a methane to oxygen ratio of ∼1:1. At a furnace temperature of 650 °C (cell temperature ∼790 °C), a peak power density of 760 mW cm -2 was attained using a mixed gas with methane, oxygen and helium flow rates of 87, 80 and 320 mL min -1 [STP], respectively. This level of power output is the highest reported in the literature for single chamber fuel cells and reflects the exceptionally high activity of the BSCF cathode for oxygen electro-reduction and its low activity for methane oxidation.

  3. The pursuit of perfect packing

    CERN Document Server

    Weaire, Denis

    2000-01-01

    In 1998 Thomas Hales dramatically announced the solution of a problem that has long teased eminent mathematicians: what is the densest possible arrangement of identical spheres? The Pursuit of Perfect Packing recounts the story of this problem and many others that have to do with packing things together. The examples are taken from mathematics, physics, biology, and engineering, including the arrangement of soap bubbles in foam, atoms in a crystal, the architecture of the bee''s honeycomb, and the structure of the Giant''s Causeway. Using an informal style and with key references, the book also includes brief accounts of the lives of many of the scientists who devoted themselves to problems of packing over many centuries, together with wry comments on their efforts. It is an entertaining introduction to the field for both specialists and the more general public.

  4. High-density growth arrest in Ras-transformed cells: low Cdk kinase activities in spite of absence of p27Kip Cdk-complexes

    DEFF Research Database (Denmark)

    Groth, Anja; Willumsen, Berthe Marie

    2005-01-01

    The ras oncogene transforms immortalized, contact-inhibited non-malignant murine fibroblasts into cells that are focus forming, exhibit increased saturation density, and are malignant in suitable hosts. Here, we examined changes in cell cycle control complexes as normal and Ras-transformed cells...... and Cdk2 complexes, as these kinases were inactivated. Ras-transformed cells failed to arrest at normal saturation density and showed no significant alterations in cell control complexes at this point. Yet, at an elevated density the Ras-transformed cells ceased to proliferate and entered a quiescent...... response to contact inhibition, a separate back-up mechanism enforced cell cycle arrest at higher cell density....

  5. Durability of Low Platinum Fuel Cells Operating at High Power Density

    Energy Technology Data Exchange (ETDEWEB)

    Polevaya, Olga [Nuvera Fuel Cells Inc.; Blanchet, Scott [Nuvera Fuel Cells Inc.; Ahluwalia, Rajesh [Argonne National Lab; Borup, Rod [Los-Alamos National Lab; Mukundan, Rangachary [Los-Alamos National Lab

    2014-03-19

    Understanding and improving the durability of cost-competitive fuel cell stacks is imperative to successful deployment of the technology. Stacks will need to operate well beyond today’s state-of-the-art rated power density with very low platinum loading in order to achieve the cost targets set forth by DOE ($15/kW) and ultimately be competitive with incumbent technologies. An accelerated cost-reduction path presented by Nuvera focused on substantially increasing power density to address non-PGM material costs as well as platinum. The study developed a practical understanding of the degradation mechanisms impacting durability of fuel cells with low platinum loading (≤0.2mg/cm2) operating at high power density (≥1.0W/cm2) and worked out approaches for improving the durability of low-loaded, high-power stack designs. Of specific interest is the impact of combining low platinum loading with high power density operation, as this offers the best chance of achieving long-term cost targets. A design-of-experiments approach was utilized to reveal and quantify the sensitivity of durability-critical material properties to high current density at two levels of platinum loading (the more conventional 0.45 mgPt.cm–1 and the much lower 0.2 mgPt.cm–2) across several cell architectures. We studied the relevance of selected component accelerated stress tests (AST) to fuel cell operation in power producing mode. New stress tests (NST) were designed to investigate the sensitivity to the addition of electrical current on the ASTs, along with combined humidity and load cycles and, eventually, relate to the combined city/highway drive cycle. Changes in the cathode electrochemical surface area (ECSA) and average oxygen partial pressure on the catalyst layer with aging under AST and NST protocols were compared based on the number of completed cycles. Studies showed elevated sensitivity of Pt growth to the potential limits and the initial particle size distribution. The ECSA loss

  6. Feeding strategies enhance high cell density cultivation and protein expression in milliliter scale bioreactors.

    Science.gov (United States)

    Faust, Georg; Janzen, Nils H; Bendig, Christoph; Römer, Lin; Kaufmann, Klaus; Weuster-Botz, Dirk

    2014-10-01

    Miniature bioreactors under parallel fed-batch operations are not only useful screening tools for bioprocess development but also provide a suitable basis for eventual scale-up. In this study, three feeding strategies were investigated: besides the established intermittent feeding by a liquid handler, an optimized microfluidic device and a new enzymatic release system were applied for parallel fed-batch cultivation of Escherichia coli HMS174(DE3) and BL21(DE3) strains in stirred-tank bioreactors on a 10 mL scale. Lower fluctuation in dissolved oxygen (DO) and higher optical densities were measured in fed-batch processes applying the microfluidic device or the enzymatic glucose/fructose release system (conversion of intermittently added sucrose by an invertase), but no difference in dry cell weights (DCW) were observed. With all three feeding strategies high cell densities were realized on a milliliter scale with final optical density measured at 600 nm (OD600 ) of 114-133 and final DCW concentrations of 69-70 g L(-1) . The effect of feeding strategies on the expression of two heterologous proteins was investigated. Whereas no impact was observed on the expression of the spider silk protein eADF4(C16), the fluorescence of enhanced green fluorescence protein (eGFP) was reproducibly lower, if an intermittent glucose feed was applied. Thus, the impact of feeding strategy on expression is strongly dependent on the E. coli strain and/or expressed protein. As a completely continuous feed supply is difficult to realize in miniature bioreactors, the enzymatic release approach from this study can be easily applied in all microfluidic system to reduce fluctuations of glucose supply and DO concentrations. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. Tailoring the rate-sensitivity of low density polyurea foams through cell wall aperture size

    Science.gov (United States)

    Ramirez, B. J.; Kingstedt, O. T.; Crum, R.; Gamez, C.; Gupta, V.

    2017-06-01

    The plateau stress and energy absorption of low density (≤300 kg/m3) polyurea (PU) foams and expanded polystyrene (EPS) were measured at deformation rates ranging from 0.004 s-1 to 5000 s-1. Low (≤10-1 s-1) strain rate testing was performed using an Instron load frame, intermediate (101-102 s-1) strain rates using a drop-weight impact tower, and high (≥103 s-1) strain rate conditions using a modified split-Hopkinson pressure bar. The plateau stress and energy absorption of low density PU foams exhibit a strong rate dependence across all deformation rates. This result has been previously unreported for low density polymer foams under low and intermediate strain rates. The strain rate sensitivity of PU foams was found to be strongly dependent on cell size for low strain rates and cell wall aperture size for intermediate and high strain rates. EPS type foam, however, remained nearly insensitive to strain rate. At low and intermediate strain rates, the plastic crushing in the EPS and the high plateau stress yield a much higher energy absorption capability than the viscoelastic dissipation in the PU foams. However, PU foams were found to display similar energy absorption properties as EPS based foams under high strain rates. Thus, controlling the strain rate sensitivity of PU foams through aperture diameter can lead to an increase in energy absorption properties at high strain rates, while simultaneously maintaining the peak stress below certain injury thresholds. Additionally, unlike EPS, which undergo plastic crushing after first impact, flexible polyurea foams will recover fully after each impact and thus will have multiple hit capabilities. This will allow these materials to have a wide range of applications, in advance body armors and protective headgears to use in low-cost protection systems for a wide range of military platforms, civilian, and space applications.

  8. Cylinder valve packing nut studies

    Energy Technology Data Exchange (ETDEWEB)

    Blue, S.C. [Martin Marietta Energy Systems, Inc., Paducah, KY (United States)

    1991-12-31

    The design, manufacture, and use of cylinder valve packing nuts have been studied to improve their resistance to failure from stress corrosion cracking. Stress frozen photoelastic models have been analyzed to measure the stress concentrations at observed points of failure. The load effects induced by assembly torque and thermal expansion of stem packing were observed by strain gaging nuts. The effects of finishing operations and heat treatment were studied by the strain gage hole boring and X-ray methods. Modifications of manufacturing and operation practices are reducing the frequency of stress corrosion failures.

  9. Mast Cell Density in Oral Lesions using Metachromatic Stains: A Comparative Study

    Directory of Open Access Journals (Sweden)

    Shilpa Chirappurath Natesan

    2017-10-01

    Full Text Available Introduction: Mast Cells (MCs are bone marrow derived granular cells, distributed throughout the body near blood vessels, nerves and subepithelial areas. MC granules stain by basic dyes but are most readily demonstrated by metachromatic dyes such as toluidine blue and azure A. Aim: This study focuses on evaluating and comparing the count of MCs by identification and staining of these cells by azure A with toluidine blue as a control, in normal oral mucosa and in various other oral pathologies. Materials and Methods: Five cases each of Normal Oral Mucosa (NOM, Inflammatory Fibrous Hyperplasia (IFH, Oral Pyogenic Granuloma (OPG, Oral Lichen Planus (OLP and Oral Squamous Cell Carcinoma (OSCC were stained with 1% toluidine blue and azure A. Results: Mean MC count was higher in all four lesions when compared to normal oral mucosa with both stains. OLP exhibited the maximum amount of mean MC count when compared to other pathologies under study. With all four lesions, toluidine blue exhibited higher number of MC density (count/high power field compared to azure A. Conclusion: Higher count of MCs was noticed in all four lesions indicating a possible role of MCs in their pathogenesis either directly or indirectly. Also, the number of degranulated MCs was more in OLP followed by OSCC, IFH and OPG.

  10. Comparison of the Blood and Lymphatic Microvessel Density of Pleomorphic Adenoma and Basal Cell Adenoma

    Directory of Open Access Journals (Sweden)

    Andresa Borges Soares

    2015-01-01

    Full Text Available Background Pleomorphic adenoma (PA is the most common tumor of the salivary gland, while basal cell adenoma (BCA is an uncommon neoplasm. Blood and lymphatic vessels are crucial for tumor metabolism. The aim of this study was to compare the blood and lymphatic vascular density and vascular and endothelial growth factor (VEGF expression in PA and BCA tumors. In addition, cell proliferation was evaluated in these tumors. Methods Blood and lymphatic vessel content, VEGF expression, and cell proliferation were analyzed in 30 cases of PA and 13 cases of BCA by immu-nohistochemistry using antibodies for CD34, CD105, D2-40, VEGF, and Mcm -2. Results Regarding CD34 and CD105 expression, PA demonstrated a high vascularity and a low number of positive vessels, respectively. D2-40-positive lymphatic vessels were mainly located in the tumor capsules, with small intratumoral lymphatic vessels observed occasionally. VEGF expression revealed a remarkably heterogeneous immunoreactivity, alternating from weak or negative to positive or intense. BCA presented significantly higher CD34, CD34, CD105, D2-40, and VEGF expression compared to PA. No significant difference was found in cell proliferation between the tumors. Conclusion Although PA and BCA are considered part of the same spectrum of differentiation, this study showed that the blood and lymphatic vascularization of these tumors is different.

  11. A dense voltage-mode Josephson memory cell insensitive to systematic variations in critical current density

    International Nuclear Information System (INIS)

    Bradley, P.; Van Duzer, T.

    1985-01-01

    A destructive read-out (DRO) memory cell using three Josephson junctions has been devised whose operation depends only on the ratio of critical currents and application of the proper read/write voltages. The effects of run-to-run and across-thewafer variations in I /SUB c/ are minimized since all three junctions for a given cell are quite close to each other. Additional advantages are: immunity from flux trapping, high circuit density, and fast switching. Since destructive read-out is generally undesirable, a self-rewriting scheme is necessary. Rows and columns of cells with drivers and sense circuits, as well as small memory arrays and decoders have been simulated on SPICE. Power dissipation of cells and bias circuits for a 1K-bit RAM is estimated at about 2 mW. Inclusion of peripheral circuitry raises this by as much as a factor of five depending on the driving scheme and speed desired. Estimated access time is appreciably less than a nanosecond. Preliminary experimental investigations are reported

  12. Enhanced photocurrent density in graphene/Si based solar cell (GSSC) by optimizing active layer thickness

    International Nuclear Information System (INIS)

    Rosikhin, Ahmad; Hidayat, Aulia Fikri; Syuhada, Ibnu; Winata, Toto

    2015-01-01

    Thickness dependent photocurrent density in active layer of graphene/Si based solar cell has been investigated via analytical – simulation study. This report is a preliminary comparison of experimental and analytical investigation of graphene/Si based solar cell. Graphene sheet was interfaced with Si thin film forming heterojunction solar cell that was treated as a device model for photocurrent generator. Such current can be enhanced by optimizing active layer thickness and involving metal oxide as supporting layer to shift photons absorption. In this case there are two type of devices model with and without TiO 2 in which the silicon thickness varied at 20 – 100 nm. All of them have examined and also compared with each other to obtain an optimum value. From this calculation it found that generated currents almost linear with thickness but there are saturated conditions that no more enhancements will be achieved. Furthermore TiO 2 layer is effectively increases photon absorption but reducing device stability, maximum current is fluctuates enough. This may caused by the disturbance of excitons diffusion and resistivity inside each layer. Finally by controlling active layer thickness, it is quite useful to estimate optimization in order to develop the next solar cell devices

  13. DEM simulation of dendritic grain random packing: application to metal alloy solidification

    Science.gov (United States)

    Olmedilla, Antonio; Založnik, Miha; Combeau, Hervé

    2017-06-01

    The random packing of equiaxed dendritic grains in metal-alloy solidification is numerically simulated and validated via an experimental model. This phenomenon is characterized by a driving force which is induced by the solid-liquid density difference. Thereby, the solid dendritic grains, nucleated in the melt, sediment and pack with a relatively low inertia-to-dissipation ratio, which is the so-called Stokes number. The characteristics of the particle packed porous structure such as solid packing fraction affect the final solidified product. A multi-sphere clumping Discrete Element Method (DEM) approach is employed to predict the solid packing fraction as function of the grain geometry under the solidification conditions. Five different monodisperse noncohesive frictionless particle collections are numerically packed by means of a vertical acceleration: a) three dendritic morphologies; b) spheres and c) one ellipsoidal geometry. In order to validate our numerical results with solidification conditions, the sedimentation and packing of two monodisperse collections (spherical and dendritic) is experimentally carried out in a viscous quiescent medium. The hydrodynamic similarity is respected between the actual phenomenon and the experimental model, that is a low Stokes number, o(10-3). In this way, the experimental average solid packing fraction is employed to validate the numerical model. Eventually, the average packing fraction is found to highly depend on the equiaxed dendritic grain sphericity, with looser packings for lower sphericity.

  14. Effects of grain size distribution on the packing fraction and shear strength of frictionless disk packings

    Science.gov (United States)

    Estrada, Nicolas

    2016-12-01

    Using discrete element methods, the effects of the grain size distribution on the density and the shear strength of frictionless disk packings are analyzed. Specifically, two recent findings on the relationship between the system's grain size distribution and its rheology are revisited, and their validity is tested across a broader range of distributions than what has been used in previous studies. First, the effects of the distribution on the solid fraction are explored. It is found that the distribution that produces the densest packing is not the uniform distribution by volume fractions as suggested in a recent publication. In fact, the maximal packing fraction is obtained when the grading curve follows a power law with an exponent close to 0.5 as suggested by Fuller and Thompson in 1907 and 1919 [Trans Am. Soc. Civ. Eng. 59, 1 (1907) and A Treatise on Concrete, Plain and Reinforced (1919), respectively] while studying mixtures of cement and stone aggregates. Second, the effects of the distribution on the shear strength are analyzed. It is confirmed that these systems exhibit a small shear strength, even if composed of frictionless particles as has been shown recently in several works. It is also found that this shear strength is independent of the grain size distribution. This counterintuitive result has previously been shown for the uniform distribution by volume fractions. In this paper, it is shown that this observation keeps true for different shapes of the grain size distribution.

  15. Chromogranin A cell density in the large intestine of Asian and European patients with irritable bowel syndrome.

    Science.gov (United States)

    El-Salhy, Magdy; Patcharatrakul, Tanisa; Hatlebakk, Jan Gunnar; Hausken, Trygve; Gilja, Odd Helge; Gonlachanvit, Sutep

    Patients with irritable bowel syndrome (IBS) in Asia show distinctive differences from those in the western world. The gastrointestinal endocrine cells appear to play an important role in the pathophysiology of IBS. The present study aimed at studying the density of chromogranin A (CgA) cells in the large intestine of Thai and Norwegian IBS patients. Thirty Thai IBS patients and 20 control subjects, and 47 Norwegian IBS patients and 20 control subjects were included. A standard colonoscopy was performed in both the patients and controls, and biopsy samples were taken from the colon and the rectum. The biopsy samples were stained with hematoxylin-eosin and immunostained for CgA. The density of CgA cells was determined by computerized image analysis. In the colon and rectum, the CgA cell densities were far higher in both IBS and healthy Thai subjects than in Norwegians. The colonic CgA cell density was lower in Norwegian IBS patients than in controls, but did not differ between Thai IBS patients and controls. In the rectum, the CgA cell densities in both Thai and Norwegian patients did not differ from those of controls. The higher densities of CgA cells in Thai subjects than Norwegians may be explained by a higher exposure to infections at childhood and the development of a broad immune tolerance, by differences in the intestinal microbiota, and/or differing diet habits. The normal CgA cell density in Thai IBS patients in contrast to that of Norwegians may be due to differences in pathophysiology.

  16. Energy Efficient Pico Cell Range Expansion and Density Joint Optimization for Heterogeneous Networks with eICIC.

    Science.gov (United States)

    Sun, Yanzan; Xia, Wenqing; Zhang, Shunqing; Wu, Yating; Wang, Tao; Fang, Yong

    2018-03-02

    Heterogeneous networks, constituted by conventional macro cells and overlaying pico cells, have been deemed a promising paradigm to support the deluge of data traffic with higher spectral efficiency and Energy Efficiency (EE). In order to deploy pico cells in reality, the density of Pico Base Stations (PBSs) and the pico Cell Range Expansion (CRE) are two important factors for the network spectral efficiency as well as EE improvement. However, associated with the range and density evolution, the inter-tier interference within the heterogeneous architecture will be challenging, and the time domain Enhanced Inter-cell Interference Coordination (eICIC) technique becomes necessary. Aiming to improve the network EE, the above factors are jointly considered in this paper. More specifically, we first derive the closed-form expression of the network EE as a function of the density of PBSs and pico CRE bias based on stochastic geometry theory, followed by a linear search algorithm to optimize the pico CRE bias and PBS density, respectively. Moreover, in order to realize the pico CRE bias and PBS density joint optimization, a heuristic algorithm is proposed to achieve the network EE maximization. Numerical simulations show that our proposed pico CRE bias and PBS density joint optimization algorithm can improve the network EE significantly with low computational complexity.

  17. Energy Efficient Pico Cell Range Expansion and Density Joint Optimization for Heterogeneous Networks with eICIC

    Directory of Open Access Journals (Sweden)

    Yanzan Sun

    2018-03-01

    Full Text Available Heterogeneous networks, constituted by conventional macro cells and overlaying pico cells, have been deemed a promising paradigm to support the deluge of data traffic with higher spectral efficiency and Energy Efficiency (EE. In order to deploy pico cells in reality, the density of Pico Base Stations (PBSs and the pico Cell Range Expansion (CRE are two important factors for the network spectral efficiency as well as EE improvement. However, associated with the range and density evolution, the inter-tier interference within the heterogeneous architecture will be challenging, and the time domain Enhanced Inter-cell Interference Coordination (eICIC technique becomes necessary. Aiming to improve the network EE, the above factors are jointly considered in this paper. More specifically, we first derive the closed-form expression of the network EE as a function of the density of PBSs and pico CRE bias based on stochastic geometry theory, followed by a linear search algorithm to optimize the pico CRE bias and PBS density, respectively. Moreover, in order to realize the pico CRE bias and PBS density joint optimization, a heuristic algorithm is proposed to achieve the network EE maximization. Numerical simulations show that our proposed pico CRE bias and PBS density joint optimization algorithm can improve the network EE significantly with low computational complexity.

  18. Packing material formulation for odorous emission biofiltration.

    Science.gov (United States)

    Gaudin, François; Andres, Yves; Le Cloirec, Pierre

    2008-01-01

    In biological gas treatment, like biofiltration of volatile organic compounds or odorous substances, the microbial nutritional needs could be a key factor of the process. The aim of this work is to propose a new packing material able to provide the lacking nutrients. In the first part of this study, two kinds of material composed of calcium carbonate, an organic binder and two different nitrogen sources, ammonium phosphate and urea phosphate (UP), were compared. The new supports present bulk densities between 0.88 and 1.15g cm(-3), moisture retention capacities close to 50% and 70%, and water cohesion capacities greater than six months for the material with 20% binder. In the second part, oxygen consumption measurements in liquid experiments show that these packing materials could enhance bacterial growth compared to pine bark or pozzolan and have no inhibitory effect. The biodegradation of different substrates (sodium sulfide and ammonia) and the support colonization by the biomass were evaluated. Finally, UP 20 was chosen and tested in a hydrogen sulfide or ammoniac biofiltration process. This showed that, for H2S concentrations greater than 100mg m(-3), UP 20 has a real advantage over pine bark or pozzolan.

  19. Wire and Packing Tape Sandwiches

    Science.gov (United States)

    Rabinowitz, Sandy

    2009-01-01

    In this article, the author describes how students can combine craft wire with clear packing tape to create a two-dimensional design that can be bent and twisted to create a three-dimensional form. Students sandwich wire designs between two layers of tape. (Contains 1 online resource.)

  20. Differential satellite cell density of type I and II fibres with lifelong endurance running in old men

    DEFF Research Database (Denmark)

    Mackey, Abigail; Karlsen, A; Couppé, C

    2014-01-01

    between these variables were determined. RESULTS: In O-Un and O-Tr, type II fibres were smaller and contained fewer satellite cells than type I fibres. However, when expressed relative to fibre area, the difference in satellite cell content between fibre types was eliminated in O-Tr, but not O...... the satellite cell pool and (ii) is associated with a similar density of satellite cells in type I and II fibres despite a failure to preserve the equal fibre type distribution of satellite cells observed in young individuals. Taken together, these data reveal a differential regulation of satellite cell content...

  1. Coking technology using packed coal mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Kuznichenko, V.M.; Shteinberg, Eh.A.; Tolstoi, A.P. (Khar' kovskii Nauchno-Issledovatel' skii Uglekhimicheskii Institut, Kharkov (Ukrainian SSR))

    1991-08-01

    Discusses coking of packed coal charges in the FRG, USSR, France, India, Poland and Czechoslovakia. The following aspects are evaluated: types of weakly caking coals that are used as components of packed mixtures, energy consumption of packing, effects of coal mixture packing on coke oven design, number of coke ovens in a battery, heating temperature, coking time, coke properties, investment and operating cost. Statistical data that characterize the Saarberg packing process used in the FRG are analyzed. Packing coal mixtures for coking improves coke quality and reduces environmental pollution. 4 refs.

  2. The Maximum Resource Bin Packing Problem

    DEFF Research Database (Denmark)

    Boyar, J.; Epstein, L.; Favrholdt, L.M.

    2006-01-01

    Usually, for bin packing problems, we try to minimize the number of bins used or in the case of the dual bin packing problem, maximize the number or total size of accepted items. This paper presents results for the opposite problems, where we would like to maximize the number of bins used...... algorithms, First-Fit-Increasing and First-Fit-Decreasing for the maximum resource variant of classical bin packing. For the on-line variant, we define maximum resource variants of classical and dual bin packing. For dual bin packing, no on-line algorithm is competitive. For classical bin packing, we find...

  3. Packing hyperspheres in high-dimensional Euclidean spaces

    Science.gov (United States)

    Skoge, Monica; Donev, Aleksandar; Stillinger, Frank H.; Torquato, Salvatore

    2006-10-01

    We present a study of disordered jammed hard-sphere packings in four-, five-, and six-dimensional Euclidean spaces. Using a collision-driven packing generation algorithm, we obtain the first estimates for the packing fractions of the maximally random jammed (MRJ) states for space dimensions d=4 , 5, and 6 to be ϕMRJ≈0.46 , 0.31, and 0.20, respectively. To a good approximation, the MRJ density obeys the scaling form ϕMRJ=c1/2d+(c2d)/2d , where c1=-2.72 and c2=2.56 , which appears to be consistent with the high-dimensional asymptotic limit, albeit with different coefficients. Calculations of the pair correlation function g2(r) and structure factor S(k) for these states show that short-range ordering appreciably decreases with increasing dimension, consistent with a recently proposed “decorrelation principle,” which, among other things, states that unconstrained correlations diminish as the dimension increases and vanish entirely in the limit d→∞ . As in three dimensions (where ϕMRJ≈0.64 ), the packings show no signs of crystallization, are isostatic, and have a power-law divergence in g2(r) at contact with power-law exponent ≈0.4 . Across dimensions, the cumulative number of neighbors equals the kissing number of the conjectured densest packing close to where g2(r) has its first minimum. Additionally, we obtain estimates for the freezing and melting packing fractions for the equilibrium hard-sphere fluid-solid transition, ϕF≈0.32 and ϕM≈0.39 , respectively, for d=4 , and ϕF≈0.20 and ϕM≈0.25 , respectively, for d=5 . Although our results indicate the stable phase at high density is a crystalline solid, nucleation appears to be strongly suppressed with increasing dimension.

  4. Increased bronchial density of CD25+Foxp3+ regulatory T cells in occupational asthma: relationship to current smoking.

    Science.gov (United States)

    Sjåheim, T B; Bjørtuft, Ø; Drabløs, P A; Kongerud, J; Halstensen, T S

    2013-05-01

    To identify activated T cell subset in the asthmatic bronchia, we developed a triple-colour immunohistofluorescence labelling technique on cryo-section to discriminate activated CD4+CD25+ T cells, (effector T cells) from Foxp3+ regulatory T cells (Treg). Additional coexpression of activation and proliferation markers was also examined in situ. Bronchial biopsies were taken from 20 aluminium potroom workers (12 smokers) with asthma (>12% reversibility), 15 non-asthmatic potroom workers (7 smokers) and 10 non-smoking, non-exposed controls. Non-smoking asthmatics had significantly higher subepithelial density of both Tregs, effector T cells, activated (HLA-DR+) CD8+ and activated CD4+ T cells. Moreover, both Tregs, effector T cells and CD8+ T cells proliferated in the non-smoking asthmatics, only. Although smoking asthmatics had no asthma-associated increase in bronchial T cell, both had a significantly increase in effector T cell to Treg ratios. The significantly increased bronchial density of Tregs, effector T cells, proliferative T cells and activated CD8+ T cells in non-smoking asthmatics clearly showed that both the effector T cells and the inhibitory Treg system were activated in asthma. © 2013 The Authors. Scandinavian Journal of Immunology © 2013 Blackwell Publishing Ltd.

  5. Interleukin 21 therapy increases the density of tumor infiltrating CD8+ T cells and inhibits the growth of syngeneic tumors

    DEFF Research Database (Denmark)

    Søndergaard, Henrik; Frederiksen, Klaus S; Thygesen, Peter

    2007-01-01

    infiltrating T cells. We treated mice bearing established subcutaneous B16 melanomas or RenCa renal cell carcinomas with intraperitoneal (i.p.) or subcutaneous (s.c.) IL-21 protein therapy and subsequently scored the densities of tumor infiltrating CD4(+) and CD8(+) T cells by immunohistochemistry. Whereas.......c. administration, which could account for the apparent increase in anti-tumor activity. Specific depletion of CD8(+) T cells with monoclonal antibodies completely abrogated the anti-tumor activity, whereas NK1.1(+) cell depletion did not affect tumor growth. In accordance, both routes of IL-21 administration...... significantly increased the density of tumor infiltrating CD8(+) T cells in both B16 and RenCa tumors; and in the RenCa model s.c. administration of IL-21 led to a significantly higher density of tumor infiltrating CD8(+) T cells compared to i.p. administration. The densities of CD4(+) T cells were unchanged...

  6. Automated computation of arbor densities: a step toward identifying neuronal cell types

    Directory of Open Access Journals (Sweden)

    Uygar eSümbül

    2014-11-01

    Full Text Available The shape and position of a neuron convey information regarding its molecular and functional identity. The identification of cell types from structure, a classic method, relies on the time-consuming step of arbor tracing. However, as genetic tools and imaging methods make data-driven approaches to neuronal circuit analysis feasible, the need for automated processing increases. Here, we first establish that mouse retinal ganglion cell types can be as precise about distributing their arbor volumes across the inner plexiform layer as they are about distributing the skeletons of the arbors. Then, we describe an automated approach to computing the spatial distribution of the dendritic arbors, or arbor density, with respect to a global depth coordinate based on this observation. Our method involves three-dimensional reconstruction of neuronal arbors by a supervised machine learning algorithm, post-processing of the enhanced stacks to remove somata and isolate the neuron of interest, and registration of neurons to each other using automatically detected arbors of the starburst amacrine interneurons as fiducial markers. In principle, this method could be generalizable to other structures of the CNS, provided that they allow sparse labeling of the cells and contain a reliable axis of spatial reference.

  7. Impact of Pancreatic Rat Islet Density on Cell Survival during Hypoxia

    Directory of Open Access Journals (Sweden)

    A. Rodriguez-Brotons

    2016-01-01

    Full Text Available In bioartificial pancreases (BP, the number of islets needed to restore normoglycaemia in the diabetic patient is critical. However, the confinement of a high quantity of islets in a limited space may impact islet survival, particularly in regard to the low oxygen partial pressure (PO2 in such environments. The aim of the present study was to evaluate the impact of islet number in a confined space under hypoxia on cell survival. Rat islets were seeded at three different concentrations (150, 300, and 600 Islet Equivalents (IEQ/cm2 and cultured in normal atmospheric pressure (160 mmHg as well as hypoxic conditions (15 mmHg for 24 hours. Cell viability, function, hypoxia-induced changes in gene expression, and cytokine secretion were then assessed. Notably, hypoxia appeared to induce a decrease in viability and increasing islet density exacerbated the observed increase in cellular apoptosis as well as the loss of function. These changes were also associated with an increase in inflammatory gene transcription. Taken together, these data indicate that when a high number of islets are confined to a small space under hypoxia, cell viability and function are significantly impacted. Thus, in order to improve islet survival in this environment during transplantation, oxygenation is of critical importance.

  8. Exceptional power density and stability at intermediate temperatures in protonic ceramic fuel cells

    Science.gov (United States)

    Choi, Sihyuk; Kucharczyk, Chris J.; Liang, Yangang; Zhang, Xiaohang; Takeuchi, Ichiro; Ji, Ho-Il; Haile, Sossina M.

    2018-02-01

    Over the past several years, important strides have been made in demonstrating protonic ceramic fuel cells (PCFCs). Such fuel cells offer the potential of environmentally sustainable and cost-effective electric power generation. However, their power outputs have lagged behind predictions based on their high electrolyte conductivities. Here we overcome PCFC performance and stability challenges by employing a high-activity cathode, PrBa0.5Sr0.5Co1.5Fe0.5O5+δ (PBSCF), in combination with a chemically stable electrolyte, BaZr0.4Ce0.4Y0.1Yb0.1O3 (BZCYYb4411). We deposit a thin dense interlayer film of the cathode material onto the electrolyte surface to mitigate contact resistance, an approach which is made possible by the proton permeability of PBSCF. The peak power densities of the resulting fuel cells exceed 500 mW cm-2 at 500 °C, while also offering exceptional, long-term stability under CO2.

  9. Development of an analytical method coupling cell membrane chromatography with gas chromatography-mass spectrometry via microextraction by packed sorbent and its application in the screening of volatile active compounds in natural products.

    Science.gov (United States)

    Li, Miao; Wang, Sicen; He, Langchong

    2015-01-01

    Natural products (NPs) are important sources of lead compounds in modern drug discovery. To facilitate the screening of volatile active compounds in NPs, we have developed a new biochromatography method that uses rat vascular smooth muscle cells (VSMC), which are rich in L-type calcium channels (LCC), to prepare the stationary phase. This integrated method, which couples cell membrane chromatography (CMC) with gas chromatography-mass spectrometry (GC-MS) via microextraction by packed sorbent (MEPS) technology, has been termed VSMC/CMC-MEPS-GC-MS. Methodological validation confirmed its specificity, reliability and convenience. Screening results for Radix Angelicae Dahuricae and Fructus Cnidii obtained using VSMC/CMC-MEPS-GC-MS were consistent with those obtained using VSMC/CMC-offline-GC-MS. MEPS connection plays as simplified solid-phase extraction and replaces the uncontrollable evaporation operation in reported offline connections, so our new method is supposed to be more efficient and reliable than the offline ones, especially for compounds that are volatile, thermally unstable or difficult to purify. In application, senkyunolide A and ligustilide were preliminary identified as the volatile active components in Rhizoma Chuanxiong. We have thus confirmed the suitability of VSMC/CMC-MEPS-GC-MS for volatile active compounds screening in NP. Copyright © 2014 Elsevier B.V. All rights reserved.

  10. Leptin deficiency-induced obesity affects the density of mast cells in abdominal fat depots and lymph nodes in mice.

    Science.gov (United States)

    Altintas, Mehmet M; Nayer, Behzad; Walford, Eric C; Johnson, Kevin B; Gaidosh, Gabriel; Reiser, Jochen; De La Cruz-Munoz, Nestor; Ortega, Luis M; Nayer, Ali

    2012-02-07

    Mast cells are implicated in the pathogenesis of obesity and insulin resistance. Here, we explored the effects of leptin deficiency-induced obesity on the density of mast cells in metabolic (abdominal fat depots, skeletal muscle, and liver) and lymphatic (abdominal lymph nodes, spleen, and thymus) organs. Fourteen-week-old male leptin-deficient ob/ob mice and their controls fed a standard chow were studied. Tissue sections were stained with toluidine blue to determine the density of mast cells. CD117/c-kit protein expression analysis was also carried out. Furthermore, mast cells containing immunoreactive tumor necrosis factor-α (TNF-α), a proinflammatory cytokine involved in obesity-linked insulin resistance, were identified by immunostaining. ob/ob mice demonstrated adiposity and insulin resistance. In abdominal fat depots, mast cells were distributed differentially. While most prevalent in subcutaneous fat in controls, mast cells were most abundant in epididymal fat in ob/ob mice. Leptin deficiency-induced obesity was accompanied by a 20-fold increase in the density of mast cells in epididymal fat, but a 13-fold decrease in subcutaneous fat. This finding was confirmed by CD117/c-kit protein expression analysis. Furthermore, we found that a subset of mast cells in epididymal and subcutaneous fat were immunoreactive for TNF-α. The proportion of mast cells immunoreactive for TNF-α was higher in epididymal than in subcutaneous fat in both ob/ob and control mice. Mast cells were also distributed differentially in retroperitoneal, mesenteric, and inguinal lymph nodes. In both ob/ob mice and lean controls, mast cells were more prevalent in retroperitoneal than in mesenteric and inguinal lymph nodes. Leptin deficiency-induced obesity was accompanied by increased mast cell density in all lymph node stations examined. No significant difference in the density of mast cells in skeletal muscle, liver, spleen, and thymus was noted between ob/ob and control mice. This study

  11. Leptin deficiency-induced obesity affects the density of mast cells in abdominal fat depots and lymph nodes in mice

    Directory of Open Access Journals (Sweden)

    Altintas Mehmet M

    2012-02-01

    Full Text Available Abstract Background Mast cells are implicated in the pathogenesis of obesity and insulin resistance. Here, we explored the effects of leptin deficiency-induced obesity on the density of mast cells in metabolic (abdominal fat depots, skeletal muscle, and liver and lymphatic (abdominal lymph nodes, spleen, and thymus organs. Fourteen-week-old male leptin-deficient ob/ob mice and their controls fed a standard chow were studied. Tissue sections were stained with toluidine blue to determine the density of mast cells. CD117/c-kit protein expression analysis was also carried out. Furthermore, mast cells containing immunoreactive tumor necrosis factor-α (TNF-α, a proinflammatory cytokine involved in obesity-linked insulin resistance, were identified by immunostaining. Results ob/ob mice demonstrated adiposity and insulin resistance. In abdominal fat depots, mast cells were distributed differentially. While most prevalent in subcutaneous fat in controls, mast cells were most abundant in epididymal fat in ob/ob mice. Leptin deficiency-induced obesity was accompanied by a 20-fold increase in the density of mast cells in epididymal fat, but a 13-fold decrease in subcutaneous fat. This finding was confirmed by CD117/c-kit protein expression analysis. Furthermore, we found that a subset of mast cells in epididymal and subcutaneous fat were immunoreactive for TNF-α. The proportion of mast cells immunoreactive for TNF-α was higher in epididymal than in subcutaneous fat in both ob/ob and control mice. Mast cells were also distributed differentially in retroperitoneal, mesenteric, and inguinal lymph nodes. In both ob/ob mice and lean controls, mast cells were more prevalent in retroperitoneal than in mesenteric and inguinal lymph nodes. Leptin deficiency-induced obesity was accompanied by increased mast cell density in all lymph node stations examined. No significant difference in the density of mast cells in skeletal muscle, liver, spleen, and thymus was

  12. Valve packing manual. A maintenance application guide

    International Nuclear Information System (INIS)

    Aikin, J.A.; McCutcheon, R.G.; Cumming, D.

    1997-01-01

    Since 1970, AECL Chalk River Mechanical Equipment Development (MED) branch has invested over 175 person years in testing related to improving valve packing performance. Successful developments, including, 'live-loading', reduced packing heights, and performance-based packing qualification testing have been implemented. Since 1986, MED and the Integrated Valve Actuator Program Task Force - Valve Packing Steering Committee (IVAP-VPSC) have been involved in the development of combination die-formed graphite packing for use in CANDU plants. Many reports, articles, and specifications have been issued. Due to the large amount of test data and reports, a more user-friendly document has been prepared for everyday use. The Valve Packing Manual is based on many years of MED research and testing, as well as operating experience from CANDU nuclear generating stations (NGS). Since 1986, packing research and testing has been funded by the CANDU Owners Group (COG), the Electric Power Research Institute (EPRI), and participating valve packing manufacturers. The Valve Packing Manual (VPM) provides topical summaries of all work related to valve packing done since 1985. It includes advances in configuration design, stem packing friction, materials specifications, and installation procedures. This paper provides an overview on the application of the VPM with a focus on qualification testing, packing configuration, and stem packing friction. (author)

  13. High-cell-density fermentation for ergosterol production by Saccharomyces cerevisiae.

    Science.gov (United States)

    Shang, Fei; Wen, Shaohong; Wang, Xi; Tan, Tianwei

    2006-01-01

    The direct feedback control of glucose using an on-line ethanol concentration monitor for ergosterol production by high-cell-density fermentation was investigated and the fermentation parameters (e.g., pH, dissolved oxygen, ethanol concentration, oxygen uptake rate, carbon dioxide evolution rate and respiratory quotient) were analyzed. Controlling glucose feeding rate in accordance with ethanol concentration and adjusting pH with ammonia during the fermentation process were effective fed-batch methods for ergosterol production. The fermentation parameters well described the variation of the whole fermentation process. Cultivation in a 5 l fermentor was carried out under the following conditions: culture temperature, 30 degrees C; pH, 5.5; agitation speed, 600 rpm; fermentation time, 60 h; controlling ethanol concentration below 1% and keeping respiratory quotient (RQ) at approximately 1.0. Under these conditions, the yeast dry weight reached 120 g/l and the ergosterol yield reached 1500 mg/l.

  14. Interdependence of initial cell density, drug concentration and exposure time revealed by real-time impedance spectroscopic cytotoxicity assay

    DEFF Research Database (Denmark)

    Caviglia, Claudia; Zor, Kinga; Canepa, Silvia

    2015-01-01

    We investigated the combined effect of the initial cell density (12 500, 35 000, 75 000, and 100 000 cells cm−2) and concentration of the anti-cancer drug doxorubicin on HeLa cells by performing timedependent cytotoxicity assays using real-time electrochemical impedance spectroscopy. A correlation...... between the rate of cell death and the initial cell seeding density was found at 2.5 μM doxorubicin concentration, whereas this was not observed at 5 or 100 μM. By sensing the changes in the cell–substrate interaction using impedance spectroscopy under static conditions, the onset of cytotoxicity...... was observed 5 h earlier than when using a standard colorimetric end-point assay (MTS) which measures changes in the mitochondrial metabolism. Furthermore, with the MTS assay no cytotoxicity was observed after 15 h of incubation with 2.5 μM doxorubicin, whereas the impedance showed at this time point cell...

  15. Changes in small intestinal chromogranin A-immunoreactive cell densities in patients with irritable bowel syndrome after receiving dietary guidance.

    Science.gov (United States)

    Mazzawi, Tarek; El-Salhy, Magdy

    2016-05-01

    Chromogranin A (CgA) is a common marker for enteroendocrine cells in the gut, and CgA-immunoreactive cell densities are abnormal in patients with irritable bowel syndrome (IBS). The majority of patients with IBS report that their symptoms develop after consuming certain foodstuffs. In the present study, we investigated the effects of dietary guidance on the total enteroendocrine cell densities in the small intestine, as detected by CgA. A total of 14 patients with IBS underwent a gastroscopy with duodenal biopsies and 11 of them also underwent a colonoscopy, with biopsy samples obtained from the ileum. Fourteen control subjects were also included. Each patient received 3 sessions of dietary guidance. Gastroscopies and colonoscopies were performed on both the controls and patients with IBS (at baseline and at 3-9 months after receiving guidance). Biopsy samples obtained from the duodenum and ileum were immunostained for CgA using the avidin-biotin complex (ABC) method and were quantified using computerized image analysis. The density of CgA-immunoreactive cells in the duodenum (mean ± SEM values) in the control subjects was 235.9 ± 31.9 cells/mm2; in the patients with IBS, the density was 36.9 ± 9.8 and 103.7 ± 16.9 cells/mm2 before and after they received dietary guidance, respectively (P=0.007). The density of CgA-immunoreactive cells in the ileum in the control subjects was 47.4 ± 8.3 cells/mm2; in the patients with IBS, the density was 48.4 ± 8.1 and 17.9 ± 4.4 cells/mm2, before and after they received dietary guidance, respectively (P=0.0006). These data indicate that changes in CgA-immunoreactive cell densities in patients with IBS after receiving dietary guidance may reflect a change in the densities of the small intestinal enteroendocrine cells, which may contribute to an improvement in the IBS symptoms.

  16. Near-critical density filling of the SF6 fluid cell for the ALI-R-DECLIC experiment in weightlessness

    Science.gov (United States)

    Lecoutre, C.; Marre, S.; Garrabos, Y.; Beysens, D.; Hahn, I.

    2018-05-01

    Analyses of ground-based experiments on near-critical fluids to precisely determine their density can be hampered by several effects, especially the density stratification of the sample, the liquid wetting behavior at the cell walls, and a possible singular curvature of the "rectilinear" diameter of the density coexisting curve. For the latter effect, theoretical efforts have been made to understand the amplitude and shape of the critical hook of the density diameter, which depart from predictions from the so-called ideal lattice-gas model of the uniaxial 3D-Ising universality class. In order to optimize the observation of these subtle effects on the position and shape of the liquid-vapor meniscus in the particular case of SF6, we have designed and filled a cell that is highly symmetrized with respect to any median plane of the total fluid volume. In such a viewed quasi-perfect symmetrical fluid volume, the precise detection of the meniscus position and shape for different orientations of the cell with respect to the Earth's gravity acceleration field becomes a sensitive probe to estimate the cell mean density filling and to test the singular diameter effects. After integration of this cell in the ALI-R insert, we take benefit of the high optical and thermal performances of the DECLIC Engineering Model. Here we present the sensitive imaging method providing the precise ground-based SF6 benchmark data. From these data analysis it is found that the temperature dependence of the meniscus position does not reflect the expected critical hook in the rectilinear density diameter. Therefore the off-density criticality of the cell is accurately estimated, before near future experiments using the same ALI-R insert in the DECLIC facility already on-board the International Space Station.

  17. Increased COX-2 expression in epithelial and stromal cells of high mammographic density tissues and in a xenograft model of mammographic density.

    Science.gov (United States)

    Chew, G L; Huo, C W; Huang, D; Hill, P; Cawson, J; Frazer, H; Hopper, J L; Haviv, I; Henderson, M A; Britt, K; Thompson, E W

    2015-08-01

    Mammographic density (MD) adjusted for age and body mass index is one of the strongest known risk factors for breast cancer. Given the high attributable risk of MD for breast cancer, chemoprevention with a safe and available agent that reduces MD and breast cancer risk would be beneficial. Cox-2 has been implicated in MD-related breast cancer risk, and was increased in stromal cells in high MD tissues in one study. Our study assessed differential Cox-2 expression in epithelial and stromal cells in paired samples of high and low MD human breast tissue, and in a validated xenograft biochamber model of MD. We also examined the effects of endocrine treatment upon Cox-2 expression in high and low MD tissues in the MD xenograft model. Paired high and low MD human breast tissue samples were immunostained for Cox-2, then assessed for differential expression and staining intensity in epithelial and stromal cells. High and low MD human breast tissues were separately maintained in biochambers in mice treated with Tamoxifen, oestrogen or placebo implants, then assessed for percentage Cox-2 staining in epithelial and stromal cells. Percentage Cox-2 staining was greater for both epithelial (p = 0.01) and stromal cells (p tissues. In high MD biochamber tissues, percentage Cox-2 staining was greater in stromal cells of oestrogen-treated versus placebo-treated tissues (p = 0.05).

  18. High-Density and Very-Low-Density Lipoprotein Have Opposing Roles in Regulating Tumor-Initiating Cells and Sensitivity to Radiation in Inflammatory Breast Cancer

    International Nuclear Information System (INIS)

    Wolfe, Adam R.; Atkinson, Rachel L.; Reddy, Jay P.; Debeb, Bisrat G.; Larson, Richard; Li, Li; Masuda, Hiroko; Brewer, Takae; Atkinson, Bradley J.; Brewster, Abeena; Ueno, Naoto T.; Woodward, Wendy A.

    2015-01-01

    Purpose: We previously demonstrated that cholesterol-lowering agents regulate radiation sensitivity of inflammatory breast cancer (IBC) cell lines in vitro and are associated with less radiation resistance among IBC patients who undergo postmastectomy radiation. We hypothesized that decreasing IBC cellular cholesterol induced by treatment with lipoproteins would increase radiation sensitivity. Here, we examined the impact of specific transporters of cholesterol (ie lipoproteins) on the responses of IBC cells to self-renewal and to radiation in vitro and on clinical outcomes in IBC patients. Methods and Materials: Two patient-derived IBC cell lines, SUM 149 and KPL4, were incubated with low-density lipoproteins (LDL), very-low-density lipoproteins (VLDL), or high-density lipoproteins (HDL) for 24 hours prior to irradiation (0-6 Gy) and mammosphere formation assay. Cholesterol panels were examined in a cohort of patients with primary IBC diagnosed between 1995 and 2011 at MD Anderson Cancer Center. Lipoprotein levels were then correlated to patient outcome, using the log rank statistical model, and examined in multivariate analysis using Cox regression. Results: VLDL increased and HDL decreased mammosphere formation compared to untreated SUM 149 and KPL4 cells. Survival curves showed enhancement of survival in both of the IBC cell lines when pretreated with VLDL and, conversely, radiation sensitization in all cell lines when pretreated with HDL. In IBC patients, higher VLDL values (>30 mg/dL) predicted a lower 5-year overall survival rate than normal values (hazard ratio [HR] = 1.9 [95% confidence interval [CI]: 1.05-3.45], P=.035). Lower-than-normal patient HDL values (<60 mg/dL) predicted a lower 5-year overall survival rate than values higher than 60 mg/dL (HR = 3.21 [95% CI: 1.25-8.27], P=.015). Conclusions: This study discovered a relationship among the plasma levels of lipoproteins, overall patient response, and radiation resistance in IBC patients

  19. High-Density and Very-Low-Density Lipoprotein Have Opposing Roles in Regulating Tumor-Initiating Cells and Sensitivity to Radiation in Inflammatory Breast Cancer

    Energy Technology Data Exchange (ETDEWEB)

    Wolfe, Adam R. [Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Morgan Welch Inflammatory Breast Cancer Research Program and Clinic, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Atkinson, Rachel L. [Morgan Welch Inflammatory Breast Cancer Research Program and Clinic, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Reddy, Jay P. [Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Debeb, Bisrat G.; Larson, Richard; Li, Li [Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Department of Clinical Cancer Prevention, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Masuda, Hiroko; Brewer, Takae [Department of Clinical Cancer Prevention, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Atkinson, Bradley J. [Department of Clinical Pharmacy Services, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Brewster, Abeena [Morgan Welch Inflammatory Breast Cancer Research Program and Clinic, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Ueno, Naoto T. [Department of Clinical Cancer Prevention, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Woodward, Wendy A., E-mail: wwoodward@mdanderson.org [Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Department of Clinical Cancer Prevention, University of Texas MD Anderson Cancer Center, Houston, Texas (United States)

    2015-04-01

    Purpose: We previously demonstrated that cholesterol-lowering agents regulate radiation sensitivity of inflammatory breast cancer (IBC) cell lines in vitro and are associated with less radiation resistance among IBC patients who undergo postmastectomy radiation. We hypothesized that decreasing IBC cellular cholesterol induced by treatment with lipoproteins would increase radiation sensitivity. Here, we examined the impact of specific transporters of cholesterol (ie lipoproteins) on the responses of IBC cells to self-renewal and to radiation in vitro and on clinical outcomes in IBC patients. Methods and Materials: Two patient-derived IBC cell lines, SUM 149 and KPL4, were incubated with low-density lipoproteins (LDL), very-low-density lipoproteins (VLDL), or high-density lipoproteins (HDL) for 24 hours prior to irradiation (0-6 Gy) and mammosphere formation assay. Cholesterol panels were examined in a cohort of patients with primary IBC diagnosed between 1995 and 2011 at MD Anderson Cancer Center. Lipoprotein levels were then correlated to patient outcome, using the log rank statistical model, and examined in multivariate analysis using Cox regression. Results: VLDL increased and HDL decreased mammosphere formation compared to untreated SUM 149 and KPL4 cells. Survival curves showed enhancement of survival in both of the IBC cell lines when pretreated with VLDL and, conversely, radiation sensitization in all cell lines when pretreated with HDL. In IBC patients, higher VLDL values (>30 mg/dL) predicted a lower 5-year overall survival rate than normal values (hazard ratio [HR] = 1.9 [95% confidence interval [CI]: 1.05-3.45], P=.035). Lower-than-normal patient HDL values (<60 mg/dL) predicted a lower 5-year overall survival rate than values higher than 60 mg/dL (HR = 3.21 [95% CI: 1.25-8.27], P=.015). Conclusions: This study discovered a relationship among the plasma levels of lipoproteins, overall patient response, and radiation resistance in IBC patients

  20. Quorum sensing influences growth and photosynthetic membrane production in high-cell-density cultivations of Rhodospirillum rubrum.

    Science.gov (United States)

    Carius, Lisa; Carius, Anke B; McIntosh, Matthew; Grammel, Hartmut

    2013-08-08

    The facultative anoxygenic photosynthetic bacterium Rhodospirillum rubrum exhibits versatile metabolic activity allowing the adaptation to rapidly changing growth conditions in its natural habitat, the microaerobic and anoxic zones of stagnant waters. The microaerobic growth mode is of special interest as it allows the high-level expression of photosynthetic membranes when grown on succinate and fructose in the dark, which could significantly simplify the industrial production of compounds associated with PM formation. However, recently we showed that PM synthesis is no longer inducible when R. rubrum cultures are grown to high cell densities under aerobic conditions. In addition a reduction of the growth rate and the continued accumulation of precursor molecules for bacteriochlorophyll synthesis were observed under high cell densities conditions. In the present work, we demonstrate that the cell density-dependent effects are reversible if the culture supernatant is replaced by fresh medium. We identified six N-acylhomoserine lactones and show that four of them are produced in varying amounts according to the growth phase and the applied growth conditions. Further, we demonstrate that N-acylhomoserine lactones and tetrapyrrole compounds released into the growth medium affect the growth rate and PM expression in high cell density cultures. In summary, we provide evidence that R. rubrum possesses a Lux-type quorum sensing system which influences the biosynthesis of PM and the growth rate and is thus likely to be involved in the phenotypes of high cell density cultures and the rapid adaptation to changing environmental conditions.

  1. Expression profiling on high-density DNA grids to detect novel targets in dendritic cells

    International Nuclear Information System (INIS)

    Weissmann, M.

    2000-10-01

    Gene expression analyzes on a large scale using DNA microarrays is a novel approach to study transcription of thousands of genes in parallel. By comparing gene expression profiles of different cell-types and of cells in different activation, novel regulatory networks will be identified that are unique to a cell-type and hence, important in its biological function. Among the differentially expressed genes many novel drug targets will be found. The Genetic department of the Novartis Research Institute was following this approach to identify novel genes, which are critical in the antigen presenting function of DCs and could become promising drug targets. Drugs that modulate effector functions of DCs towards induction of energy or tolerance in T-cells could be useful in the treatment of chronic inflammatory or autoimmune diseases. By using specific robotics equipment high-density cDNA grids on nylon membranes have been produced for hybridizations with various radioactive labeled DNA probes. By our format, based on 384 well plates and limited by the resolution power of our current image analysis software, 27.648 cDNA clones, bacterial colonies or pure DNA, were spotted on one filter. For RNA profiling, we generated filters containing a collection of genes expressed in peripheral blood DCs or monocytes and characterized by oligonucleotide fingerprinting (ONF) as being differentially expressed. The gene collection contained many unknown genes. Sequence analysis of to date 18.000 cDNA clones led to an estimate of 5.000 non-redundant genes being represented in the collection. 10 % of them are either completely unknown or homologous to rare ESTs (expressed sequence tags) in the public EST database. These clones occurred predominantly in small fingerprint clusters and were therefore assumed to be rarely expressed in DCs or monocytes. Some of those genes may become novel drug targets if their expression is DC specific or induced by external stimuli driving DCs into

  2. Hypostatic jammed packings of frictionless nonspherical particles

    OpenAIRE

    VanderWerf, Kyle; Jin, Weiwei; Shattuck, Mark D.; O'Hern, Corey S.

    2017-01-01

    We perform computational studies of static packings of a variety of nonspherical particles including circulo-lines, circulo-polygons, ellipses, asymmetric dimers, and dumbbells to determine which shapes form hypostatic versus isostatic packings and to understand why hypostatic packings of nonspherical particles can be mechanically stable despite having fewer contacts than that predicted from na\\"ive constraint counting. To generate highly accurate force- and torque-balanced packings of circul...

  3. Selection of packing materials for gas absorption

    OpenAIRE

    Arachchige, Udara Sampath P.; Melaaen, Morten Christian

    2012-01-01

    Carbon dioxide (CO2) capture is the most viable option to minimize the environmental impact by CO2 emissions. Amine scrubbing process is the well-known technology to achieve that. There are several packing types available for gas absorption. Both random and structured packing were considered in the simulation studies. The main idea behind this study was to select the best packing material which gives lowest re-boiler duty. Complete removal model was developed for selected packing materials. T...

  4. Hyperthermic survival of Chinese hamster ovary cells as a function of cellular population density at the time of plating

    International Nuclear Information System (INIS)

    Highfield, D.P.; Holahan, E.V.; Holahan, P.K.; Dewey, W.C.

    1984-01-01

    The survival of synchronous G 1 or asynchronous Chinese hamster ovary cells in vitro to heat treatment may depend on the cellular population density at the time of heating and/or as the cells are cultured after heating. The addition of lethally irradiated feeder cells may increase survival at 10 -3 by as much as 10- to 100-fold for a variety of conditions when cells are heated either in suspension culture or as monolayers with or without trypsinization. The protective effect associated with feeder cells appears to be associated with close cell-to-cell proximity. However, when cells are heated without trypsinization about 24 hr or later after plating, when adaptation to monolayer has occurred, the protective effect is reduced; i.e., addition of feeder cells enhances survival much less, for example, about 2- to 3-fold at 10 -2 -10 -3 survival. Also, the survival of a cell to heat is independent of whether the neighboring cell in a microcolony is destined to live or die. Finally, if protective effects associated with cell density do occur and are not controlled, serious artifacts can result as the interaction of heat and radiation is studied; for example, survival curves can be moved upward, and thus changed in shape as the number of cells plated is increased with an increase in the hyperthermic treatment or radiation dose following hyperthermia. Therefore, to understand mechanisms and to obtain information relevant to populations of cells in close proximity, such as those in vivo, these cellular population density effects should be considered and understood

  5. Safer v. Estate of Pack.

    Science.gov (United States)

    1996-07-11

    The Superior Court of New Jersey, Appellate Division, recognized "a physician's duty to warn those known to be at risk of avoidable harm from a genetically transmissible condition." During the 1950s, Dr. George Pack treated Donna Shafer's father for a cancerous blockage of the colon and multiple polyposis. In 1990, Safer was diagnosed with the same condition, which she claims is inherited, and, if not diagnosed and treated, invariably will lead to metastic colorectal cancer. Safer alleged that Dr. Pack knew the hereditary nature of the disease, yet failed to warn the immediate family, thus breaching his professional duty to warn. The court did not follow the analysis of the trial court, that a physician has no legal duty to warn the child of a patient of the genetic risk of disease because no physician and patient relationship exists between the doctor and the child.

  6. Fast Searching in Packed Strings

    DEFF Research Database (Denmark)

    Bille, Philip

    2009-01-01

    Given strings P and Q the (exact) string matching problem is to find all positions of substrings in Q matching P. The classical Knuth-Morris-Pratt algorithm [SIAM J. Comput., 1977] solves the string matching problem in linear time which is optimal if we can only read one character at the time....... However, most strings are stored in a computer in a packed representation with several characters in a single word, giving us the opportunity to read multiple characters simultaneously. In this paper we study the worst-case complexity of string matching on strings given in packed representation. Let m...... word-RAM with logarithmic word size we present an algorithm using time O(n/log(sigma) n + m + occ) Here occ is the number of occurrences of P in Q. For m = o(n) this improves the O(n) bound...

  7. Edaravone attenuates monocyte adhesion to endothelial cells induced by oxidized low-density lipoprotein

    Energy Technology Data Exchange (ETDEWEB)

    Li, Zhijuan, E-mail: zjlee038@163.com; Cheng, Jianxin; Wang, Liping

    2015-10-30

    Oxidized low-density lipoprotein (oxLDL) plays a vital role in recruitment of monocytes to endothelial cells, which is important during early stages of atherosclerosis development. Edaravone, a potent and novel scavenger of free radicals inhibiting hydroxyl radicals, has been clinically used to reduce the neuronal damage following ischemic stroke. In the present study, Edaravone was revealed to markedly reduce oxLDL-induced monocyte adhesion to human umbilical vein endothelial cells (HUVECs). The inhibitory mechanism of Edaravone was associated with suppression of the chemokine MCP-1 and adhesion molecule VCAM-1 and ICAM-1 expression. In addition, luciferase reporter assay results revealed that administration of Edaravone attenuated the increase in NF-κB transcriptional activity induced by oxLDL. Notably, it's also shown that Edaravone treatment blocked oxLDL induced p65 nuclear translocation in HUVECs. Results indicate that Edaravone negatively regulates endothelial inflammation. - Highlights: • Edaravone reduces oxLDL-induced monocyte adhesion to HUVECs. • Edaravone attenuates oxLDL-induced expression of MCP-1, VCAM-1, and ICAM-1. • Edaravone reduces NF-κB transcriptional activity and p65 nuclear translocation.

  8. Paralytic shellfish toxin concentration and cell density changes in Pyrodinium bahamense -Noctiluca scintillans feeding experiments.

    Science.gov (United States)

    Azanza, Rhodora V; Cruz, Lourdes J; Cariño, Flerida A; Blanco, Alelea G; Butardo, Vito M

    2010-05-01

    For the first time the potential of Noctiluca scintillans, a non-toxic mixotrophic dinoflagellate, in bioconverting and/or excreting saxitoxin has been illustrated, thus contributing to the limited knowledge on the aspects of toxin pathways in the food chain/web and predator-prey preferences. Noctiluca growth rate increased with higher Pyrodinium concentration but the ratio of Noctiluca to Pyrodinium should at least be 1:250 cells per mL. Noctiluca fed with Pyrodinium alone was found to decrease in number suggesting that the nutrients from this prey were insufficient. This was confirmed by the improved cell density of Noctiluca upon addition of 0.01% casitone to the Pyrodinium-fed Noctiluca. The alternative prey (Gymnodinium sanguineum) slowed down the grazing impact of Noctiluca on Pyrodinium. Noctiluca depleted Gymnodinium earlier than Pyrodinium showing preference over a prey with less saxitoxin. After the feeding experiments, total saxitoxin levels decreased to 72% in the Noctiluca-Pyrodinium setup whereas no saxitoxin was detected in the Noctiluca culture fed with Pyrodinium and G. sanguineum. It is possible that Gymnodinium can provide some nutrients needed to make Noctiluca more efficient in bioconverting saxitoxin. Copyright 2009 Elsevier Ltd. All rights reserved.

  9. Optimized LTE Cell Planning with Varying Spatial and Temporal User Densities

    KAUST Repository

    Ghazzai, Hakim

    2015-03-09

    Base station deployment in cellular networks is one of the fundamental problems in network design. This paper proposes a novel method for the cell planning problem for the fourth generation (4G) cellular networks using meta-heuristic algorithms. In this approach, we aim to satisfy both cell coverage and capacity constraints simultaneously by formulating an optimization problem that captures practical planning aspects. The starting point of the planning process is defined through a dimensioning exercise that captures both coverage and capacity constraints. Afterwards, we implement a meta-heuristic algorithm based on swarm intelligence (e.g., particle swarm optimization or the recently-proposed grey wolf optimizer) to find suboptimal base station locations that satisfy both problem constraints in the area of interest which can be divided into several subareas with different spatial user densities. Subsequently, an iterative approach is executed to eliminate eventual redundant base stations. We also perform Monte Carlo simulations to study the performance of the proposed scheme and compute the average number of users in outage. Next, the problems of green planning with regards to temporal traffic variation and planning with location constraints due to tight limits on electromagnetic radiations are addressed, using the proposed method. Finally, in our simulation results, we apply our proposed approach for different scenarios with different subareas and user distributions and show that the desired network quality of service targets are always reached even for large-scale problems.

  10. Optimized LTE cell planning for multiple user density subareas using meta-heuristic algorithms

    KAUST Repository

    Ghazzai, Hakim

    2014-09-01

    Base station deployment in cellular networks is one of the most fundamental problems in network design. This paper proposes a novel method for the cell planning problem for the fourth generation 4G-LTE cellular networks using meta heuristic algorithms. In this approach, we aim to satisfy both coverage and cell capacity constraints simultaneously by formulating a practical optimization problem. We start by performing a typical coverage and capacity dimensioning to identify the initial required number of base stations. Afterwards, we implement a Particle Swarm Optimization algorithm or a recently-proposed Grey Wolf Optimizer to find the optimal base station locations that satisfy both problem constraints in the area of interest which can be divided into several subareas with different user densities. Subsequently, an iterative approach is executed to eliminate eventual redundant base stations. We have also performed Monte Carlo simulations to study the performance of the proposed scheme and computed the average number of users in outage. Results show that our proposed approach respects in all cases the desired network quality of services even for large-scale dimension problems.

  11. Random packing of colloids and granular matter

    NARCIS (Netherlands)

    Wouterse, A.

    2008-01-01

    This thesis deals with the random packing of colloids and granular matter. A random packing is a stable disordered collection of touching particles, without long-range positional and orientational order. Experimental random packings of particles with the same shape but made of different materials

  12. Complications of balloon packing in epistaxis

    NARCIS (Netherlands)

    Vermeeren, Lenka; Derks, Wynia; Fokkens, Wytske; Menger, Dirk Jan

    2015-01-01

    Although balloon packing appears to be efficient to control epistaxis, severe local complications can occur. We describe four patients with local lesions after balloon packing. Prolonged balloon packing can cause damage to nasal mucosa, septum and alar skin (nasal mucosa, the cartilaginous skeleton

  13. Increased extracellular matrix density decreases MCF10A breast cell acinus formation in 3D culture conditions.

    Science.gov (United States)

    Lance, Amanda; Yang, Chih-Chao; Swamydas, Muthulekha; Dean, Delphine; Deitch, Sandy; Burg, Karen J L; Dréau, Didier

    2016-01-01

    The extracellular matrix (ECM) contributes to the generation and dynamic of normal breast tissue, in particular to the generation of polarized acinar and ductal structures. In vitro 3D culture conditions, including variations in the composition of the ECM, have been shown to directly influence the formation and organization of acinus-like and duct-like structures. Furthermore, the density of the ECM appears to also play a role in the normal mammary tissue and tumour formation. Here we show that the density of the ECM directly influences the number, organization and function of breast acini. Briefly, non-malignant human breast MCF10A cells were incubated in increasing densities of a Matrigel®-collagen I matrix. Elastic moduli near and distant to the acinus structures were measured by atomic force microscopy, and the number of acinus structures was determined. Immunochemistry was used to investigate the expression levels of E-cadherin, laminin, matrix metalloproteinase-14 and ß-casein in MCF10A cells. The modulus of the ECM was significantly increased near the acinus structures and the number of acinus structures decreased with the increase in Matrigel-collagen I density. As evaluated by the expression of laminin, the organization of the acinus structures present was altered as the density of the ECM increased. Increases in both E-cadherin and MMP14 expression by MCF10A cells as ECM density increased were also observed. In contrast, MCF10A cells expressed lower ß-casein levels as the ECM density increased. Taken together, these observations highlight the key role of ECM density in modulating the number, organization and function of breast acini. Copyright © 2013 John Wiley & Sons, Ltd.

  14. Effects of heat and water transport on the performance of polymer electrolyte membrane fuel cell under high current density operation

    International Nuclear Information System (INIS)

    Tabuchi, Yuichiro; Shiomi, Takeshi; Aoki, Osamu; Kubo, Norio; Shinohara, Kazuhiko

    2010-01-01

    Key challenges to the acceptance of polymer electrolyte membrane fuel cells (PEMFCs) for automobiles are the cost reduction and improvement in its power density for compactness. In order to get the solution, the further improvement in a fuel cell performance is required. In particular, under higher current density operation, water and heat transport in PEMFCs has considerable effects on the cell performance. In this study, the impact of heat and water transport on the cell performance under high current density was investigated by experimental evaluation of liquid water distribution and numerical validation. Liquid water distribution in MEA between rib and channel area is evaluated by neutron radiography. In order to neglect the effect of liquid water in gas channels and reactant species concentration distribution in the flow direction, the differential cell was used in this study. Experimental results suggested that liquid water under the channel was dramatically changed with rib/channel width. From the numerical study, it is found that the change of liquid water distribution was significantly affected by temperature distribution in MEA between rib and channel area. In addition, not only heat transport but also water transport through the membrane also significantly affected the cell performance under high current density operation.

  15. Towards optimal packed string matching

    DEFF Research Database (Denmark)

    Ben-Kiki, Oren; Bille, Philip; Breslauer, Dany

    2014-01-01

    In the packed string matching problem, it is assumed that each machine word can accommodate up to α characters, thus an n-character string occupies n/α memory words.(a) We extend the Crochemore–Perrin constant-space O(n)-time string-matching algorithm to run in optimal O(n/α) time and even in real......-time, achieving a factor α speedup over traditional algorithms that examine each character individually. Our macro-level algorithm only uses the standard AC0 instructions of the word-RAM model (i.e. no integer multiplication) plus two specialized micro-level AC0 word-size packed-string instructions. The main word...... matching work.(b) We also consider the complexity of the packed string matching problem in the classical word-RAM model in the absence of the specialized micro-level instructions wssm and wslm. We propose micro-level algorithms for the theoretically efficient emulation using parallel algorithms techniques...

  16. Serum amyloid A stimulates macrophage foam cell formation via lectin-like oxidized low-density lipoprotein receptor 1 upregulation

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Ha Young, E-mail: hayoung@skku.edu [Department of Biological Science, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Mitochondria Hub Regulation Center, Dong-A University, Busan 602-714 (Korea, Republic of); Kim, Sang Doo [Department of Biological Science, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Baek, Suk-Hwan [Department of Biochemistry and Molecular Biology, College of Medicine, Yeungnam University, Daegu 705-717 (Korea, Republic of); Choi, Joon Hyuk [Department of Pathology, College of Medicine, Yeungnam University, Daegu 705-717 (Korea, Republic of); Cho, Kyung-Hyun [School of Biotechnology, Yeungnam University, Gyeongsan 712-749 (Korea, Republic of); Zabel, Brian A. [Palo Alto Institute for Research and Education, Veterans Affairs Hospital, Palo Alto, CA 94304 (United States); Bae, Yoe-Sik, E-mail: yoesik@skku.edu [Department of Biological Science, Sungkyunkwan University, Suwon 440-746 (Korea, Republic of); Mitochondria Hub Regulation Center, Dong-A University, Busan 602-714 (Korea, Republic of); Samsung Advanced Institute for Health Sciences and Technology, Sungkyunkwan University, Seoul 135-710 (Korea, Republic of)

    2013-03-29

    Highlights: ► SAA induced macrophage foam cell formation. ► SAA stimulated upregulation of lectin-like oxidized low-density lipoprotein receptor 1 (LOX1). ► SAA-induced LOX1 expression and foam cell formation is mediated by JNK/NF-κB signaling. ► HDL-conjugated SAA also stimulates foam cell formation via LOX1 upregulation. ► The finding reveals a novel mechanism of action of SAA in the pathogenesis of atherosclerosis. -- Abstract: Elevated levels of serum amyloid A (SAA) is a risk factor for cardiovascular diseases, however, the role of SAA in the pathophysiology of atherosclerosis remains unclear. Here we show that SAA induced macrophage foam cell formation. SAA-stimulated foam cell formation was mediated by c-jun N-terminal kinase (JNK) signaling. Moreover, both SAA and SAA-conjugated high density lipoprotein stimulated the expression of the important scavenger receptor lectin-like oxidized low-density lipoprotein receptor 1 (LOX1) via nuclear factor-κB (NF-κB). A LOX1 antagonist carrageenan significantly blocked SAA-induced foam cell formation, indicating that SAA promotes foam cell formation via LOX1 expression. Our findings therefore suggest that SAA stimulates foam cell formation via LOX1 induction, and thus likely contributes to atherogenesis.

  17. Nicotine-induced expression of low-density lipoprotein receptor in oral epithelial cells.

    Directory of Open Access Journals (Sweden)

    Satoshi Ito

    Full Text Available BACKGROUND: Nicotine use is one of the most important risk factors for the development of cardiovascular and periodontal diseases. Numerous reports have suggested the possible contribution of disturbed lipid metabolism for the development of both disease groups. Despite these observations, little is known about the relationship between tobacco smoking and the development of these diseases. Our previous microarray data revealed that nicotine induced low-density lipoprotein receptor (LDLR expression in oral epithelial cells (OECs. The aim of the present study was to confirm nicotine-mediated LDLR induction and to elucidate the signaling mechanisms leading to the augmented expression of LDLR in OECs. METHODS AND RESULTS: LDLR and nicotinic acetylcholine receptor (nAChR subunit expression was detected by real-time PCR. The production of LDLR was demonstrated by immunofluorescence staining. nAChR-mediated LDLR induction was examined by pre-incubation of the cells with its specific inhibitor, α-bungarotoxin (α-BTX. The functional importance of transcription factor specific protein 1 (Sp1 was examined by luciferase assay, mithramycin pre-incubation or by small interfering RNA (siRNA transfection. The specific binding of Sp1 to R3 region of LDLR 5'-untranslated region was demonstrated with electrophoretic mobility shift assay (EMSA and streptavidin-agarose precipitation assay followed by western blotting. The results confirmed that nicotine induced LDLR expression at the transcriptional level. Nicotine was sensed by nAChR and the signal was transduced by Sp1 which bound to the R3 region of LDLR gene. Augmented production of LDLR in the gingival epithelial cells was further demonstrated by immunofluorescence staining using the gingival tissues obtained from the smoking patients. CONCLUSIONS: Taken together, the results suggested that nicotine might contribute to the development of both cardiovascular and periodontal diseases by inducing the LDLR in

  18. Effect of PEG Grafting Density and Hydrodynamic Volume on Gold Nanoparticle-Cell Interactions: An Investigation on Cell Cycle, Apoptosis, and DNA Damage.

    Science.gov (United States)

    Uz, Metin; Bulmus, Volga; Alsoy Altinkaya, Sacide

    2016-06-14

    In this study, interactions of polyethylene glycol (PEG)-coated gold nanoparticles (AuNPs) with cells were investigated with particular focus on the relationship between the PEG layer properties (conformation, grafting density, and hydrodynamic volume) and cell cycle arrest, apoptosis, and DNA damage. Steric hindrance and PEG hydrodynamic volume controlled the protein adsorption, whereas the AuNP core size and PEG hydrodynamic volume were primary factors for cell uptake and viability. At all PEG grafting densities, the particles caused significant cell cycle arrest and DNA damage against CaCo2 and PC3 cells without apoptosis. However, at a particular PEG grafting density (∼0.65 chains/nm(2)), none of these severe damages were observed on 3T3 cells indicating discriminating behavior of the healthy (3T3) and cancer (PC3 and CaCo2) cells. It was concluded that the PEG grafting density and hydrodynamic volume, tuned with the PEG concentration and AuNP size, played an important role in particle-cell interactions.

  19. Prefrontal cortical parvalbumin and somatostatin expression and cell density increase during adolescence and are modified by BDNF and sex.

    Science.gov (United States)

    Du, X; Serena, K; Hwang, W; Grech, A M; Wu, Y W C; Schroeder, A; Hill, R A

    2018-04-01

    Brain-derived neurotrophic factor (BDNF) is known to play a critical role early in the development of cortical GABAergic interneurons. Recently our laboratory and others have shown protracted development of specific subpopulations of GABAergic interneurons extending into adolescence. BDNF expression also changes significantly across adolescent development. However the role of BDNF in regulating GABAergic changes across adolescence remains unclear. Here, we performed a week-by-week analysis of the protein expression and cell density of three major GABAergic interneurons, parvalbumin (PV), somatostatin (SST) and calretinin (Cal) in the medial prefrontal cortex from prepubescence (week 3) to adulthood (week 12). In order to assess how BDNF and sex might influence the adolescent trajectory of GABAergic interneurons we compared WT as well as BDNF heterozygous (+/-) male and female mice. In both males and females PV expression increases during adolescent development in the mPFC. Compared to wild-types, PV expression was reduced in male but not female BDNF+/- mice throughout adolescent development. This reduction in protein expression corresponded with reduced cell density, specifically within the infralimbic prefrontal cortex. SST expression increased in early adolescent WT females and this upregulation was delayed in BDNF+/-. SST cell density also increased in early adolescent mPFC of WT female mice, with BDNF+/- again showing a reduced pattern of expression. Cal protein expression was also sex-dependently altered across adolescence with WT males showing a steady decline but that of BDNF+/- remaining unaltered. Reduced cell density in on the other hand was observed particularly in male BDNF+/- mice. In females, Cal protein expression and cell density remained largely stable. Our results show that PV, SST and calretinin interneurons are indeed still developing into early adolescence in the mPFC and that BDNF plays a critical, sex-specific role in mediating expression and

  20. Hydraulically refueled battery employing a packed bed metal particle electrode

    Science.gov (United States)

    Siu, Stanley C.; Evans, James W.

    1998-01-01

    A secondary zinc air cell, or another selected metal air cell, employing a spouted/packed metal particle bed and an air electrode. More specifically, two embodiments of a cell, one that is capable of being hydraulically recharged, and a second that is capable of being either hydraulically or electrically recharged. Additionally, each cell includes a sloped bottom portion to cause stirring of the electrolyte/metal particulate slurry when the cell is being hydraulically emptied and refilled during hydraulically recharging of the cell.

  1. Incremental Capacity Analysis of a Lithium-Ion Battery Pack for Different Charging Rates

    DEFF Research Database (Denmark)

    Kalogiannis, Theodoros; Stroe, Daniel-Ioan; Nyborg, Jonas

    2017-01-01

    -depth investigation of two battery packs composed of 14 Lithium-ion cells each; for the purpose of evaluating the applicability and the challenges of the ICA on a battery pack level by means of different charging current rates. Also, at a certain charging current, the influence of the temperature on the ICA curves...

  2. Preoperative anaemia is associated with increased allogeneic pack red cell transfusion in revision hip and knee joint arthroplasty: a retrospective analysis of 5387 patients over a 10-year period at a single high volume centre.

    Science.gov (United States)

    Kasivisvanathan, R; Ramesh, V; Rao Baikady, R; Nadaraja, S

    2016-08-01

    To estimate the prevalence of preoperative World Health Organization (WHO) defined anaemia in patients presenting for revision hip and knee arthroplasty and its association with transfusion of allogeneic packed red blood cells (PRBC). Studies have mainly investigated the prevalence of preoperative anaemia in primary and not revision hip and knee joint arthroplasty. An analysis of a prospectively collected patient data for 5387 patients having revision hip or knee arthroplasty over a 10-year period at a single high volume centre was conducted. Logistic regression was used to assess whether the presence of WHO defined preoperative anaemia as well as other risk factors were associated with inpatient allogeneic PRBC transfusion. There were 5387 patients assessed of which 3021 (56·01%) patients had revision total hip replacements and 2366 (43·09%) had revision total knee arthroplasty. Of these patients 1956 (36·03%) had preoperative WHO defined anaemia. A total of 2034 (37·08%) patients received at least one unit of allogeneic PRBC during their primary hospital admission. In the final model preoperative WHO defined anaemia was independently associated with allogeneic PRBC transfusion in hip and knee revision surgery OR 4·042 (4·012-4·072 95% CI) CONCLUSIONS: Preoperative anaemia is common in patients presenting for revision hip and knee arthroplasty and independently associated with transfusion of allogeneic PRBC. © 2016 British Blood Transfusion Society.

  3. Stomatal and pavement cell density linked to leaf internal CO2 concentration

    Science.gov (United States)

    Šantrůček, Jiří; Vráblová, Martina; Šimková, Marie; Hronková, Marie; Drtinová, Martina; Květoň, Jiří; Vrábl, Daniel; Kubásek, Jiří; Macková, Jana; Wiesnerová, Dana; Neuwithová, Jitka; Schreiber, Lukas

    2014-01-01

    Background and Aims Stomatal density (SD) generally decreases with rising atmospheric CO2 concentration, Ca. However, SD is also affected by light, air humidity and drought, all under systemic signalling from older leaves. This makes our understanding of how Ca controls SD incomplete. This study tested the hypotheses that SD is affected by the internal CO2 concentration of the leaf, Ci, rather than Ca, and that cotyledons, as the first plant assimilation organs, lack the systemic signal. Methods Sunflower (Helianthus annuus), beech (Fagus sylvatica), arabidopsis (Arabidopsis thaliana) and garden cress (Lepidium sativum) were grown under contrasting environmental conditions that affected Ci while Ca was kept constant. The SD, pavement cell density (PCD) and stomatal index (SI) responses to Ci in cotyledons and the first leaves of garden cress were compared. 13C abundance (δ13C) in leaf dry matter was used to estimate the effective Ci during leaf development. The SD was estimated from leaf imprints. Key Results SD correlated negatively with Ci in leaves of all four species and under three different treatments (irradiance, abscisic acid and osmotic stress). PCD in arabidopsis and garden cress responded similarly, so that SI was largely unaffected. However, SD and PCD of cotyledons were insensitive to Ci, indicating an essential role for systemic signalling. Conclusions It is proposed that Ci or a Ci-linked factor plays an important role in modulating SD and PCD during epidermis development and leaf expansion. The absence of a Ci–SD relationship in the cotyledons of garden cress indicates the key role of lower-insertion CO2 assimilation organs in signal perception and its long-distance transport. PMID:24825295

  4. Application of Higher Density Iron Oxide Nanoparticle Pellicles to Enrich the Plasma Membrane and Its Proteome from Cells in Suspension.

    Science.gov (United States)

    Rose, Rebecca L; Choksawangkarn, Waeowalee; Fenselau, Catherine

    2018-01-01

    Enrichment of the plasma membrane represents one valuable method to characterize the surfaceome, along with other plasma membrane and structural proteins. Currently, the overlapping densities of many subcellular organelles hinder enrichment of the plasma membrane by centrifugation. However, external access to the plasma membrane of intact cells allows the attachment of a nanoparticle pellicle to enhance its density and facilitate enrichment. We describe the synthesis of iron oxide nanoparticles, attachment of the pellicle to suspended cells, and recovery of plasma membrane proteins for proteomic analysis.

  5. Close-packed (polytypic) structures in molecular-dynamics simulations

    International Nuclear Information System (INIS)

    Moody, M.; Ray, J.R.; Rahman, A.

    1987-01-01

    Molecular-dynamics (MD) computer-simulation studies are used to study close-packed structures found in solid-phase atomic systems interacting via a Morse potential (parametrized to model Ni). A graphical display of particle positions [a (112-bar0) projection] within the parallelepiped forming the MD cell is illustrated. Such a graphic projection allows accurate, complete, and readily visual recognition of the stacking order of close-packed planes and is a much more effective way of identifying polytypes than a study of the pair-distribution function for the structure. These illustrations demonstrate the polytypic nature of previously and newly recognized MD close-packed structures. When assuming compatibility with periodic boundary conditions, as is conventional in MD, only certain polytypes are allowed for an MD simulation system. A discussion of compatibility between close-packed structures and the periodic boundary conditions is presented. The pair coordination numbers, geometrical structure-factor intensities, and potential-energy lattice sums are then calculated for some of these compatible structures. This paper concludes that, through careful consideration, a considerable variety of close-packed physical systems may be appropriately modeled with use of MD computer simulation. Conversely, proper interpretation of the data obtained during such studies may require awareness of the findings presented here

  6. Improved probiotic viability in stress environments with post-culture of alginate-chitosan microencapsulated low density cells.

    Science.gov (United States)

    Song, Huiyi; Yu, Weiting; Liu, Xiudong; Ma, Xiaojun

    2014-08-08

    In this study, probiotics (Saccharomyces cerevisiae Y235) were entrapped in alginate-chitosan microcapsules by emulsification/internal gelation technique. Two different encapsulation patterns were established as directly entrapped high density cells (dEHDC) and entrapped low density cells with culture (ELDCwc). The performance of microencapsulated cells, with free cells (FC) as control, was investigated against sequential stress environments of freeze-drying, storage, and simulated gastrointestinal fluids. After being freeze-dried without cryoprotectant, the survival rate of ELDCwc (14.33%) was significantly higher than 10.00% of dEHDC, and 0.05% of FC. The lower temperature (-20°C) and ELDCwc pattern were beneficial for keeping viable cells at 7.00 logCFU g(-1) after 6 months. Furthermore, the ELDCwc microcapsule maintained viable cells of 6.29 logCFU g(-1) after incubation in SGF and SIF. These studies demonstrated that the pattern of entrapped low density cells with culture was an effective and superior technique of resisting harmful stress environments. Copyright © 2014 Elsevier Ltd. All rights reserved.

  7. Increased Chromogranin A Cell Density in the Large Intestine of Patients with Irritable Bowel Syndrome after Receiving Dietary Guidance

    Directory of Open Access Journals (Sweden)

    Tarek Mazzawi

    2015-01-01

    Full Text Available The large intestine contains five types of endocrine cells that regulate its functions by sensing its luminal contents and releasing specific hormones. Chromogranin A (CgA is a common marker for the gastrointestinal endocrine cells, and it is abnormal in irritable bowel syndrome (IBS patients. Most IBS patients relate their symptoms to certain food elements. The present study investigated the effect of dietary guidance on the total endocrine cells of the large intestine as detected by CgA in 13 IBS patients. Thirteen control subjects were also included. Each patient received three sessions of dietary guidance. Colonoscopies were performed on controls and patients (at baseline and at 3–9 months after receiving guidance. Biopsy samples from the colon and rectum were immunostained for CgA and quantified by computerized image analysis. The densities of CgA cells in the total colon (mean ± SEM among the controls and the IBS patients before and after receiving dietary guidance were 83.3±10.1, 38.6±3.7, and 64.7±4.2 cells/mm2, respectively (P=0.0004, and were unchanged in the rectum. In conclusion, the increase in CgA cell density after receiving dietary guidance may reflect a change in the densities of the large intestinal endocrine cells causing an improvement in the IBS symptoms.

  8. Argyrophil cell density in the oxyntic mucosa is higher in female than in male morbidly obese patients

    Directory of Open Access Journals (Sweden)

    F.A.N. Maksud

    2013-05-01

    Full Text Available Obesity is a multifactorial disorder often associated with many important diseases such as diabetes, hypertension and other metabolic syndrome conditions. Argyrophil cells represent almost the total population of endocrine cells of the human gastric mucosa and some reports have described changes of specific types of these cells in patients with obesity and metabolic syndrome. The present study was designed to evaluate the global population of argyrophil cells of the gastric mucosa of morbidly obese and dyspeptic non-obese patients. Gastric biopsies of antropyloric and oxyntic mucosa were obtained from 50 morbidly obese patients (BMI >40 and 50 non-obese patients (17 dyspeptic overweight and 33 lean individuals and processed for histology and Grimelius staining for argyrophil cell demonstration. Argyrophil cell density in the oxyntic mucosa of morbidly obese patients was higher in female (238.68 ± 83.71 cells/mm2 than in male patients (179.31 ± 85.96 cells/mm2 and also higher in female (214.20 ± 50.38 cells/mm2 than in male (141.90 ± 61.22 cells/mm2 morbidly obese patients with metabolic syndrome (P = 0.01 and P = 0.02, respectively. In antropyloric mucosa, the main difference in argyrophil cell density was observed between female morbidly obese patients with (167.00 ± 69.30 cells/mm2 and without (234.00 ± 69.54 cells/mm2 metabolic syndrome (P = 0.001. In conclusion, the present results show that the number of gastric argyrophil cells could be under gender influence in patients with morbid obesity. In addition, gastric argyrophil cells seem to behave differently among female morbidly obese patients with and without metabolic syndrome.

  9. Argyrophil cell density in the oxyntic mucosa is higher in female than in male morbidly obese patients

    Energy Technology Data Exchange (ETDEWEB)

    Maksud, F.A.N. [Laboratório de Patologia Digestiva e Neuroendócrina, Faculdade de Medicina, Universidade Federal de Minas Gerais, Belo Horizonte, MG (Brazil); Faculdade de Medicina, Universidade Federal de Ouro Preto, Ouro Preto, MG (Brazil); Kakehasi, A.M. [Laboratório de Patologia Digestiva e Neuroendócrina, Faculdade de Medicina, Universidade Federal de Minas Gerais, Belo Horizonte, MG (Brazil); Barbosa, A.J.A. [Laboratório de Patologia Digestiva e Neuroendócrina, Faculdade de Medicina, Universidade Federal de Minas Gerais, Belo Horizonte, MG (Brazil); Instituto Alfa de Gastroenterologia, Belo Horizonte, MG (Brazil)

    2013-04-05

    Obesity is a multifactorial disorder often associated with many important diseases such as diabetes, hypertension and other metabolic syndrome conditions. Argyrophil cells represent almost the total population of endocrine cells of the human gastric mucosa and some reports have described changes of specific types of these cells in patients with obesity and metabolic syndrome. The present study was designed to evaluate the global population of argyrophil cells of the gastric mucosa of morbidly obese and dyspeptic non-obese patients. Gastric biopsies of antropyloric and oxyntic mucosa were obtained from 50 morbidly obese patients (BMI >40) and 50 non-obese patients (17 dyspeptic overweight and 33 lean individuals) and processed for histology and Grimelius staining for argyrophil cell demonstration. Argyrophil cell density in the oxyntic mucosa of morbidly obese patients was higher in female (238.68 ± 83.71 cells/mm{sup 2}) than in male patients (179.31 ± 85.96 cells/mm{sup 2}) and also higher in female (214.20 ± 50.38 cells/mm{sup 2}) than in male (141.90 ± 61.22 cells/mm{sup 2}) morbidly obese patients with metabolic syndrome (P = 0.01 and P = 0.02, respectively). In antropyloric mucosa, the main difference in argyrophil cell density was observed between female morbidly obese patients with (167.00 ± 69.30 cells/mm{sup 2}) and without (234.00 ± 69.54 cells/mm{sup 2}) metabolic syndrome (P = 0.001). In conclusion, the present results show that the number of gastric argyrophil cells could be under gender influence in patients with morbid obesity. In addition, gastric argyrophil cells seem to behave differently among female morbidly obese patients with and without metabolic syndrome.

  10. Argyrophil cell density in the oxyntic mucosa is higher in female than in male morbidly obese patients

    International Nuclear Information System (INIS)

    Maksud, F.A.N.; Kakehasi, A.M.; Barbosa, A.J.A.

    2013-01-01

    Obesity is a multifactorial disorder often associated with many important diseases such as diabetes, hypertension and other metabolic syndrome conditions. Argyrophil cells represent almost the total population of endocrine cells of the human gastric mucosa and some reports have described changes of specific types of these cells in patients with obesity and metabolic syndrome. The present study was designed to evaluate the global population of argyrophil cells of the gastric mucosa of morbidly obese and dyspeptic non-obese patients. Gastric biopsies of antropyloric and oxyntic mucosa were obtained from 50 morbidly obese patients (BMI >40) and 50 non-obese patients (17 dyspeptic overweight and 33 lean individuals) and processed for histology and Grimelius staining for argyrophil cell demonstration. Argyrophil cell density in the oxyntic mucosa of morbidly obese patients was higher in female (238.68 ± 83.71 cells/mm 2 ) than in male patients (179.31 ± 85.96 cells/mm 2 ) and also higher in female (214.20 ± 50.38 cells/mm 2 ) than in male (141.90 ± 61.22 cells/mm 2 ) morbidly obese patients with metabolic syndrome (P = 0.01 and P = 0.02, respectively). In antropyloric mucosa, the main difference in argyrophil cell density was observed between female morbidly obese patients with (167.00 ± 69.30 cells/mm 2 ) and without (234.00 ± 69.54 cells/mm 2 ) metabolic syndrome (P = 0.001). In conclusion, the present results show that the number of gastric argyrophil cells could be under gender influence in patients with morbid obesity. In addition, gastric argyrophil cells seem to behave differently among female morbidly obese patients with and without metabolic syndrome

  11. Helical Defect Packings in a Quasi-One-Dimensional System of Cylindrically Confined Hard Spheres

    Science.gov (United States)

    Yamchi, Mahdi Zaeifi; Bowles, Richard K.

    2015-07-01

    We use a combination of analytical theory and molecular dynamics simulation to study the inherent structure landscape of a system of hard spheres confined to narrow cylindrical channels of diameter 1 +√{3 }/2 packing is a perfect, symmetrical single helix. The presence of topological defects that change the local chirality of the helix lowers the packing density and alters the local packing structure. The helical sections between defects become asymmetrical and are better described as a double helix with angular twists between the first and second nearest neighbors that are determined by the defect separation distance. Increasing the fraction of defects unwinds the two helical strands so that the least dense structure is a nonhelical packing of two zigzag chains. We also show that the packing effects of the helical section induce a long-range, entropically driven attraction between the defects.

  12. Diagnosis of iron deficiency anemia using density-based fractionation of red blood cells.

    Science.gov (United States)

    Hennek, Jonathan W; Kumar, Ashok A; Wiltschko, Alex B; Patton, Matthew R; Lee, Si Yi Ryan; Brugnara, Carlo; Adams, Ryan P; Whitesides, George M

    2016-10-05

    Iron deficiency anemia (IDA) is a nutritional disorder that impacts over one billion people worldwide; it may cause permanent cognitive impairment in children, fatigue in adults, and suboptimal outcomes in pregnancy. IDA can be diagnosed by detection of red blood cells (RBCs) that are characteristically small (microcytic) and deficient in hemoglobin (hypochromic), typically by examining the results of a complete blood count performed by a hematology analyzer. These instruments are expensive, not portable, and require trained personnel; they are, therefore, unavailable in many low-resource settings. This paper describes a low-cost and rapid method to diagnose IDA using aqueous multiphase systems (AMPS)-thermodynamically stable mixtures of biocompatible polymers and salt that spontaneously form discrete layers having sharp steps in density. AMPS are preloaded into a microhematocrit tube and used with a drop of blood from a fingerstick. After only two minutes in a low-cost centrifuge, the tests (n = 152) were read by eye with a sensitivity of 84% (72-93%) and a specificity of 78% (68-86%), corresponding to an area under the curve (AUC) of 0.89. The AMPS test outperforms diagnosis by hemoglobin alone (AUC = 0.73) and is comparable to methods used in clinics like reticulocyte hemoglobin concentration (AUC = 0.91). Standard machine learning tools were used to analyze images of the resulting tests captured by a standard desktop scanner to 1) slightly improve diagnosis of IDA-sensitivity of 90% (83-96%) and a specificity of 77% (64-87%), and 2) predict several important red blood cell parameters, such as mean corpuscular hemoglobin concentration. These results suggest that the use of AMPS combined with machine learning provides an approach to developing point-of-care hematology.

  13. Enhanced xylose fermentation by engineered yeast expressing NADH oxidase through high cell density inoculums.

    Science.gov (United States)

    Zhang, Guo-Chang; Turner, Timothy L; Jin, Yong-Su

    2017-03-01

    Accumulation of reduced byproducts such as glycerol and xylitol during xylose fermentation by engineered Saccharomyces cerevisiae hampers the economic production of biofuels and chemicals from cellulosic hydrolysates. In particular, engineered S. cerevisiae expressing NADPH-linked xylose reductase (XR) and NAD + -linked xylitol dehydrogenase (XDH) produces substantial amounts of the reduced byproducts under anaerobic conditions due to the cofactor difference of XR and XDH. While the additional expression of a water-forming NADH oxidase (NoxE) from Lactococcus lactis in engineered S. cerevisiae with the XR/XDH pathway led to reduced glycerol and xylitol production and increased ethanol yields from xylose, volumetric ethanol productivities by the engineered yeast decreased because of growth defects from the overexpression of noxE. In this study, we introduced noxE into an engineered yeast strain (SR8) exhibiting near-optimal xylose fermentation capacity. To overcome the growth defect caused by the overexpression of noxE, we used a high cell density inoculum for xylose fermentation by the SR8 expressing noxE. The resulting strain, SR8N, not only showed a higher ethanol yield and lower byproduct yields, but also exhibited a high ethanol productivity during xylose fermentation. As noxE overexpression elicits a negligible growth defect on glucose conditions, the beneficial effects of noxE overexpression were substantial when a mixture of glucose and xylose was used. Consumption of glucose led to rapid cell growth and therefore enhanced the subsequent xylose fermentation. As a result, the SR8N strain produced more ethanol and fewer byproducts from a mixture of glucose and xylose than the parental SR8 strain without noxE overexpression. Our results suggest that the growth defects from noxE overexpression can be overcome in the case of fermenting lignocellulose-derived sugars such as glucose and xylose.

  14. The hyperbolic effect of density and strength of inter beta-cell coupling on islet bursting: a theoretical investigation

    Directory of Open Access Journals (Sweden)

    Wang Xujing

    2008-08-01

    Full Text Available Abstract Background Insulin, the principal regulating hormone of blood glucose, is released through the bursting of the pancreatic islets. Increasing evidence indicates the importance of islet morphostructure in its function, and the need of a quantitative investigation. Recently we have studied this problem from the perspective of islet bursting of insulin, utilizing a new 3D hexagonal closest packing (HCP model of islet structure that we have developed. Quantitative non-linear dependence of islet function on its structure was found. In this study, we further investigate two key structural measures: the number of neighboring cells that each β-cell is coupled to, nc, and the coupling strength, gc. Results β-cell clusters of different sizes with number of β-cells nβ ranging from 1–343, nc from 0–12, and gc from 0–1000 pS, were simulated. Three functional measures of islet bursting characteristics – fraction of bursting β-cells fb, synchronization index λ, and bursting period Tb, were quantified. The results revealed a hyperbolic dependence on the combined effect of nc and gc. From this we propose to define a dimensionless cluster coupling index or CCI, as a composite measure for islet morphostructural integrity. We show that the robustness of islet oscillatory bursting depends on CCI, with all three functional measures fb, λ and Tb increasing monotonically with CCI when it is small, and plateau around CCI = 1. Conclusion CCI is a good islet function predictor. It has the potential of linking islet structure and function, and providing insight to identify therapeutic targets for the preservation and restoration of islet β-cell mass and function.

  15. LOW-TEMPERATURE, ANODE-SUPPORTED HIGH POWER DENSITY SOLID OXIDE FUEL CELLS WITH NANOSTRUCTURED ELECTRODES

    Energy Technology Data Exchange (ETDEWEB)

    Professor Anil V. Virkar

    2003-05-23

    This report summarizes the work done during the entire project period, between October 1, 1999 and March 31, 2003, which includes a six-month no-cost extension. During the project, eight research papers have, either been, published, accepted for publication, or submitted for publication. In addition, several presentations have been made in technical meetings and workshops. The project also has provided support for four graduate students working towards advanced degrees. The principal technical objective of the project was to analyze the role of electrode microstructure on solid oxide fuel cell performance. Prior theoretical work conducted in our laboratory demonstrated that the particle size of composite electrodes has a profound effect on cell performance; the finer the particle size, the lower the activation polarization, the better the performance. The composite cathodes examined consisted of electronically conducting perovskites such as Sr-doped LaMnO{sub 3} (LSM) or Sr-doped LaCoO{sub 3} (LSC), which is also a mixed conductor, as the electrocatalyst, and yttria-stabilized zirconia (YSZ) or rare earth oxide doped CeO{sub 2} as the ionic conductor. The composite anodes examined were mixtures of Ni and YSZ. A procedure was developed for the synthesis of nanosize YSZ by molecular decomposition, in which unwanted species were removed by leaching, leaving behind nanosize YSZ. Anode-supported cells were made using the as-synthesized powders, or using commercially acquired powders. The electrolyte was usually a thin ({approx}10 microns), dense layer of YSZ, supported on a thick ({approx}1 mm), porous Ni + YSZ anode. The cathode was a porous mixture of electrocatalyst and an ionic conductor. Most of the cell testing was done at 800 C with hydrogen as fuel and air as the oxidant. Maximum power densities as high as 1.8 W/cm{sup 2} were demonstrated. Polarization behavior of the cells was theoretically analyzed. A limited amount of cell testing was done using liquid

  16. Carbamylated low-density lipoprotein induces proliferation and increases adhesion molecule expression of human coronary artery smooth muscle cells.

    Science.gov (United States)

    Asci, Gulay; Basci, Ali; Shah, Sudhir V; Basnakian, Alexei; Toz, Huseyin; Ozkahya, Mehmet; Duman, Soner; Ok, Ercan

    2008-12-01

    Presence of accelerated atherosclerosis in dialysis patients cannot be entirely explained by conventional risk factors. Exposure to urea, which is elevated in patients with kidney disease, leads to the carbamylation of proteins. We investigated the effects of carbamylated low-density lipoprotein (cLDL) on human coronary artery vascular smooth muscle cells (VSMC). Native LDL (nLDL) was carbamylated with potassium cyanate. Cells were incubated with different concentrations of cLDL carbamylated at different time points. Cytotoxicity, apoptosis, proliferation (bromodeoxyuridine incorporation), expression of adhesion molecules and extracellular matrix protein synthesis were studied. Carbamylated low-density lipoprotein exposure leads to morphological alterations and presence of cellular debris. Neither nLDL nor cLDL caused apoptosis. Lactate dehydrogenase (LDH) release was not different between groups. Carbamylated low-density lipoprotein led to a striking proliferation in VSMC compared to nLDL. Carbamylated low-density lipoprotein significantly increased intercellular adhesion molecule-1 and vascular cell adhesion molecule-1 expression compared to the control. The effects of cLDL on proliferation and adhesion molecule expression were dose-dependent and correlated with the degree of low-density lipoprotein carbamylation. cLDL had no effect on extracellular matrix protein synthesis. The results support the hypothesis that cLDL may contribute to the pathogenesis of atherosclerosis in uraemic patients.

  17. The Prognostic Impact of NK/NKT Cell Density in Periampullary Adenocarcinoma Differs by Morphological Type and Adjuvant Treatment.

    Science.gov (United States)

    Lundgren, Sebastian; Warfvinge, Carl Fredrik; Elebro, Jacob; Heby, Margareta; Nodin, Björn; Krzyzanowska, Agnieszka; Bjartell, Anders; Leandersson, Karin; Eberhard, Jakob; Jirström, Karin

    2016-01-01

    Natural killer (NK) cells and NK T cells (NKT) are vital parts of tumour immunosurveillance. However, their impact on prognosis and chemotherapy response in periampullary adenocarcinoma, including pancreatic cancer, has not yet been described. Immune cell-specific expression of CD56, CD3, CD68 and CD1a was analysed by immunohistochemistry on tissue microarrays with tumours from 175 consecutive cases of periampullary adenocarcinoma, 110 of pancreatobiliary type (PB-type) and 65 of intestinal type (I-type) morphology. Kaplan-Meier and Cox regression analysis were applied to determine the impact of CD56+ NK/NKT cells on 5-year overall survival (OS). High density of CD56+ NK/NKT cells correlated with low N-stage and lack of perineural, lymphatic vessel and peripancreatic fat invasion. High density of CD56+ NK/NKT cells was associated with prolonged OS in Kaplan-Meier analysis (p = 0.003), and in adjusted Cox regression analysis (HR = 0.49; 95% CI 0.29-0.86). The prognostic effect of high CD56+ NK/NKT cell infiltration was only evident in cases not receiving adjuvant chemotherapy in PB-type tumours (p for interaction = 0.014). This study demonstrates that abundant infiltration of CD56+ NK/NKT cells is associated with a prolonged survival in periampullary adenocarcinoma. However, the negative interaction with adjuvant treatment is noteworthy. NK cell enhancing strategies may prove to be successful in the management of these cancers.

  18. PORTSMOUTH ON-SITE DISPOSAL CELL HIGH DENSITY POLYETHYLENE GEOMEMBRANE LONGEVITY

    Energy Technology Data Exchange (ETDEWEB)

    Phifer, M.

    2012-01-31

    It is anticipated that high density polyethylene (HDPE) geomembranes will be utilized within the liner and closure cap of the proposed On-Site Disposal Cell (OSDC) at the Portsmouth Gaseous Diffusion Plant. The likely longevity (i.e. service life) of HDPE geomembranes in OSDC service is evaluated within the following sections of this report: (1) Section 2.0 provides an overview of HDPE geomembranes, (2) Section 3.0 outlines potential HDPE geomembranes degradation mechanisms, (3) Section 4.0 evaluates the applicability of HDPE geomembrane degradation mechanisms to the Portsmouth OSDC, (4) Section 5.0 provides a discussion of the current state of knowledge relative to the longevity (service life) of HDPE geomembranes, including the relation of this knowledge to the Portsmouth OSDC, and (5) Section 6.0 provides summary and conclusions relative to the anticipated service life of HDPE geomembranes in OSDC service. Based upon this evaluation it is anticipated that the service life of HDPE geomembranes in OSDC service would be significantly greater than the 200 year service life assumed for the OSDC closure cap and liner HDPE geomembranes. That is, a 200 year OSDC HDPE geomembrane service life is considered a conservative assumption.

  19. Time dependent – density functional theory characterization of organic dyes for dye-sensitized solar cells

    KAUST Repository

    Hilal, Rifaat

    2017-06-19

    We aim at providing better insight into the parameters that govern the intramolecular charge transfer (ICT) and photo-injection processes in dyes for dye-sensitised solar cells (DSSC). Density functional theory (DFT) and time-dependent DFT (TD-DFT) calculations are utilized to study the geometry, electronic structure, electrostatic potential (ESP) and absorption spectrum, for a representative donor-π bridge-acceptor (D–π–A) dye for DSSC. The coplanar geometry of the dye (D1) facilitates strong conjugation and considerable delocalization originating the π CT interaction from donor to acceptor orbitals and the hyper-conjugative interactions involving Rydberg states. A model simulating the adsorption of the dye on the TiO surface is utilized to estimate binding energies. The effect of fluorine substituents in the π-spacer on the quantum efficiency of DSSCs was investigated. Gibb’s free energy values, redox potentials, excited state lifetime, non-linear optical properties (NLO) and driving forces for D1 and its fluorinated derivatives were computed.

  20. [Evaluation of bone mineral density in children with sickle cell disease].

    Science.gov (United States)

    Garrido Colino, C; Beléndez Bieler, C; Pérez Díaz, M; Cela de Julián, E

    2015-04-01

    To evaluate bone mineral density (BMD) in children with sickle cell disease (SCD) in the Community of Madrid. The BMD was estimated in 40 children with SCD, and with an age range between 3 and 16 years, using densitometry (DXA), as recommended by the International Society for Clinical Densitometry (ISCD). The mean age at the time of the study was 7.97±3.95 years, the mean value of the DXA expressed in Z -score was -0.91±1.46 with a range of minimum values - 5.30 and 2.30 maximum. More than half (57.5%) of all the children had normal BMD (Z>-1), 25% had low BMD (Z between -1 and -2), and 17.5% showed an abnormal Z -score values of osteoporosis (Z -score<-2). The Pearson linear correlation was statistically significant between Z -score value and the haemoglobin level (r=0.368, p=.019), finding no correlation with the levels of 25 (OH) vitamin D. Prospective studies are needed with a larger number of patients to understand the future implications of bone densitometry changes and associated risk factors. Copyright © 2013 Asociación Española de Pediatría. Published by Elsevier España, S.L.U. All rights reserved.

  1. Systematic development and optimization of chemically defined medium supporting high cell density growth of Bacillus coagulans.

    Science.gov (United States)

    Chen, Yu; Dong, Fengqing; Wang, Yonghong

    2016-09-01

    With determined components and experimental reducibility, the chemically defined medium (CDM) and the minimal chemically defined medium (MCDM) are used in many metabolism and regulation studies. This research aimed to develop the chemically defined medium supporting high cell density growth of Bacillus coagulans, which is a promising producer of lactic acid and other bio-chemicals. In this study, a systematic methodology combining the experimental technique with flux balance analysis (FBA) was proposed to design and simplify a CDM. The single omission technique and single addition technique were employed to determine the essential and stimulatory compounds, before the optimization of their concentrations by the statistical method. In addition, to improve the growth rationally, in silico omission and addition were performed by FBA based on the construction of a medium-size metabolic model of B. coagulans 36D1. Thus, CDMs were developed to obtain considerable biomass production of at least five B. coagulans strains, in which two model strains B. coagulans 36D1 and ATCC 7050 were involved.

  2. Optimization of high cell density fermentation process for recombinant nitrilase production in E. coli.

    Science.gov (United States)

    Sohoni, Sujata Vijay; Nelapati, Dhanaraj; Sathe, Sneha; Javadekar-Subhedar, Vaishali; Gaikaiwari, Raghavendra P; Wangikar, Pramod P

    2015-01-01

    Nitrilases constitute an important class of biocatalysts for chiral synthesis. This work was undertaken with the aim to optimize nitrilase production in a host that is well-studied for protein production. Process parameters were optimized for high cell density fermentation, in batch and fed-batch modes, of Escherichia coli BL21 (DE3) expressing Pseudomonas fluorescens nitrilase with a T7 promoter based expression system. Effects of different substrates, temperature and isopropyl β-D-1-thiogalactopyranoside (IPTG) induction on nitrilase production were studied. Super optimal broth containing glycerol but without an inducer gave best results in batch mode with 32 °C as the optimal temperature. Use of IPTG led to insoluble protein and lower enzyme activity. Optimized fed-batch strategy resulted in significant improvement in specific activity as well as volumetric productivity of the enzyme. On a volumetric basis, the activity improved 40-fold compared to the unoptimized batch process. Copyright © 2015 Elsevier Ltd. All rights reserved.

  3. Development of chemically defined media supporting high-cell-density growth of lactococci, enterococci, and streptococci.

    Science.gov (United States)

    Zhang, Guiying; Mills, David A; Block, David E

    2009-02-01

    Lactococcus lactis IL1403 was used as an experimental strain to develop a chemically defined medium for study of the physiology and metabolic pathways of lactococci. An experimental leave-one-out technique was employed to determine the necessity of each of the 57 chemical components used in medium development. A statistical experimental design approach including three fractional factorial designs and a central composite design was used to optimize the fermentation process with 21 variables composed of 19 nutritional factors grouped from the 57 components and two environmental factors (initial pH and temperature). For L. lactis IL1403, the maximum biomass concentrations obtained with the two optimal chemically defined media developed in this study (ZMB1 and ZMB2) were generally 3.5- to 4-fold higher than the maximum biomass concentrations obtained with the previously described best synthetic media (SA) and 50% to 68% higher than the maximum biomass concentrations obtained with M17, a complex medium commonly used for lactococci. The new chemically defined media support high-cell-density growth of numerous strains of L. lactis, Enterococcus faecalis, and Streptococcus thermophilus.

  4. Bone mineral density, vitamin D, and nutritional status of children submitted to hematopoietic stem cell transplantation.

    Science.gov (United States)

    Campos, Denise Johnsson; Boguszewski, César Luiz; Funke, Vaneuza Araujo Moreira; Bonfim, Carmem Maria Sales; Kulak, Carolina Aguiar Moreira; Pasquini, Ricardo; Borba, Victória Zeghbi Cochenski

    2014-06-01

    The aim of the study was to evaluate the effect of allogeneic hematopoietic stem cell transplantation (HSCT) on bone mineral density (BMD), serum vitamin D levels, and nutritional status of 50 patients between ages 4 and 20 y. We conducted pre-HSCT and 6-mo post-HSCT evaluations. We measured BMD at the lumbar spine (LS) and total body (TB) by dual energy x-ray absorptiometry (DXA); body composition by bioimpedance analysis, and dietary intakes of calcium and vitamin D using the 24-h recall and semiquantitative food frequency questionnaire methods. We observed a significant reduction in BMD 6 mo post-HSCT. Nearly half (48%) of patients had reductions at the LS (average -9.6% ± 6.0%), and patients who developed graft-versus-host disease (GVHD) had the greatest reductions (-5.6% versus 1.2%, P nutritional status, and vitamin D levels. We suggest that early routine assessment be done to permit prevention and treatment. Copyright © 2014 Elsevier Inc. All rights reserved.

  5. Paraffin oil as a "methane vector" for rapid and high cell density cultivation of Methylosinus trichosporium OB3b.

    Science.gov (United States)

    Han, Bing; Su, Tao; Wu, Hao; Gou, Zhongxuan; Xing, Xin-Hui; Jiang, Hao; Chen, Yin; Li, Xin; Murrell, J Colin

    2009-06-01

    Slow growth and relatively low cell densities of methanotrophs have limited their uses in industrial applications. In this study, a novel method for rapid cultivation of Methylosinus trichosporium OB3b was studied by adding a water-immiscible organic solvent in the medium. Paraffin oil was the most effective at enhancing cell growth and final cell density. This is at least partially due to the increase of methane gas transfer between gas and medium phases since methane solubility is higher in paraffin than in water/nitrate minimal salt medium. During cultivation with paraffin oil at 5% (v/v) in the medium, M. trichosporium OB3b cells also showed higher concentrations of the intermediary metabolites, such as formic acid and pyruvic acid, and consumed more methane compared with the control. Paraffin as methane vector to improve methanotroph growth was further studied in a 5-L fermentor at three concentrations (i.e., 2.5%, 5%, and 10%). Cell density reached about 14 g dry weight per liter with 5% paraffin, around seven times higher than that of the control (without paraffin). Cells cultivated with paraffin tended to accumulate around the interface between oil droplets and the water phase and could exist in oil phase in the case of 10% (v/v) paraffin. These results indicated that paraffin could enhance methanotroph growth, which is potentially useful in cultivation of methanotrophs in large scale in industry.

  6. Nanomodification of the electrodes in microbial fuel cell: impact of nanoparticle density on electricity production and microbial community

    DEFF Research Database (Denmark)

    Al Atraktchi, Fatima Al-Zahraa; Zhang, Yifeng; Angelidaki, Irini

    2014-01-01

    densities of gold (Au) nanoparticles were sputtered on carbon paper as electrodes of MFCs. The results show that power generation increased with Au nanoparticle density on the electrodes. The highest power density was obtained by depositing carbon paper with an Au thickness of 50 nm and 100 nm on each side......, respectively, which was 1.22-1.88 times higher than that obtained with plain carbon paper electrode (control). Furthermore, the Coulombic efficiency was increased with the Au density. Consequently, the maximum lag time before stable power generation was shortened by 1.22 times the lag time of the control......The nano-decoration of electrode with nanoparticles is one effective way to enhance power output of microbial fuel cells (MFCs). However, the amount of nanoparticles used for decoration has not been optimized yet, and how it affects the microbial community is still unknown. In this study, different...

  7. Improved extended Kalman filter for state of charge estimation of battery pack

    Science.gov (United States)

    Sepasi, Saeed; Ghorbani, Reza; Liaw, Bor Yann

    2014-06-01

    It is difficult to model the behavior of the battery pack accurately due to the electrochemical characteristics variations among cells of a battery pack. As a result, accurate state-of-charge (SOC) and state-of-health (SOH) estimation for the battery pack is a case provocation. The estimation process poses more challenges after substantial battery aging. This paper tries to estimate the SOC of a Li-ion battery pack for an electrical vehicle using improved extended Kalman filter (IEKF) which benefits from considering aging phenomenon in the electrical model of cells. In order to assemble a battery pack, we find cells with similar electrochemical characteristics. Model adaptive algorithm is applied on the corresponding cells of a string to minimize cell-to-cell variation's effect. During the operation, the values of electrical model of each cell are updated by the same algorithm to compensate aging effects on SOC estimation error. The mean value of updated cell's model is used for a single unit cell model of the pack used at IEKF to achieve more accurate SOC estimation. The algorithm's fast response and low computational burden, makes on-board estimation practical. The experimental results reveal that the proposed approach's SOC and voltage estimation errors do not exceed 1.5%.

  8. Experimental Study of a Pack of Supercapacitors Used in Electric Vehicles

    Directory of Open Access Journals (Sweden)

    Amari Mansour

    2017-01-01

    Full Text Available Electric vehicles have recently attracted research interest. An electric vehicle is composed of two energy sources, such as fuel cells and ultracapacitors, which are employed to provide, respectively, the steady-state and transient power demanded by the vehicle. A bidirectional DC-DC converter is needed to interface the ultracapacitor to a DC bus. The pack of ultracapacitor consists of many cells in series and possibly also in parallel. In this regard, this paper introduces a comparative study between two packs of supercapacitors. The first supercapacitor pack is composed of ten cells in series but the second supercapacitor pack is composed of five cells in series and two parallel circuits. Each cell is characterized by 2.5 V and 100 F. A number of practical tests are presented.

  9. Experimental Study of a Pack of Supercapacitors Used in Electric Vehicles.

    Science.gov (United States)

    Mansour, Amari; Mohamed Hedi, Chabchoub; Faouzi, Bacha

    2017-01-01

    Electric vehicles have recently attracted research interest. An electric vehicle is composed of two energy sources, such as fuel cells and ultracapacitors, which are employed to provide, respectively, the steady-state and transient power demanded by the vehicle. A bidirectional DC-DC converter is needed to interface the ultracapacitor to a DC bus. The pack of ultracapacitor consists of many cells in series and possibly also in parallel. In this regard, this paper introduces a comparative study between two packs of supercapacitors. The first supercapacitor pack is composed of ten cells in series but the second supercapacitor pack is composed of five cells in series and two parallel circuits. Each cell is characterized by 2.5 V and 100 F. A number of practical tests are presented.

  10. Dynamic Simulation of Random Packing of Polydispersive Fine Particles

    Science.gov (United States)

    Ferraz, Carlos Handrey Araujo; Marques, Samuel Apolinário

    2018-02-01

    In this paper, we perform molecular dynamic (MD) simulations to study the two-dimensional packing process of both monosized and random size particles with radii ranging from 1.0 to 7.0 μm. The initial positions as well as the radii of five thousand fine particles were defined inside a rectangular box by using a random number generator. Both the translational and rotational movements of each particle were considered in the simulations. In order to deal with interacting fine particles, we take into account both the contact forces and the long-range dispersive forces. We account for normal and static/sliding tangential friction forces between particles and between particle and wall by means of a linear model approach, while the long-range dispersive forces are computed by using a Lennard-Jones-like potential. The packing processes were studied assuming different long-range interaction strengths. We carry out statistical calculations of the different quantities studied such as packing density, mean coordination number, kinetic energy, and radial distribution function as the system evolves over time. We find that the long-range dispersive forces can strongly influence the packing process dynamics as they might form large particle clusters, depending on the intensity of the long-range interaction strength.

  11. Molecular packing and area compressibility of lipid bilayers

    International Nuclear Information System (INIS)

    White, S.H.; King, G.I.

    1985-01-01

    Knowledge of the molecular packing of lipids and water in lipid bilayers is important for understanding bilayer mechanics and thermodynamics. Information on packing is most often obtained from x-ray or neutron diffraction measurements. Given the d spacing, composition, and partial specific volumes of the lipid and water, it is a simple matter to calculate the area per lipid molecule, bilayer thickness, and bilayer mass density. The partial specific volumes are commonly assumed to be those of bulk water and of lipid in excess water regardless of the degree of bilayer hydration. The authors present evidence here that these assumptions should be seriously questioned. At low hydrations, they find the head groups of egg and dioleoyl lecithin to be much less tightly packed than previously thought and the partial specific volume of water to be considerably smaller than 1 ml/g. Because the molecular packing affects the mechanical properties of bilayers, they use the results to reevaluate published experiments concerning the elastic area compressibility modulus of egg lecithin bilayers and the repulsive hydration force between bilayers

  12. The granule cell density of the dentate gyrus following administration of Urtica dioica extract to young diabetic rats.

    Science.gov (United States)

    Fazeli, S A; Gharravi, A M; Ghafari, S; Jahanshahi, M; Golalipour, M J

    2008-08-01

    Urtica dioica L. Stinging nettle has long been known worldwide as a medicinal plant. To study the benefits of the nettle in diabetic encephalopathy, the granule cell density of the dentate gyrus of diabetic rats was studied following administration of Urtica dioica extract. A total of 24 male albino Wistar rats were allocated equally to normal, diabetic, preventive and treatment groups. Hyperglycaemia was induced by streptozotocin (80 mg/kg) in the animals of the diabetic and treatment groups. One week after injection of the streptozotocin the animals in the treatment group received a hydroalcoholic extract of Urtica dioica (100 mg/kg/day) for 4 weeks intraperitoneally. The rats of the preventive group received hydroalcoholic extract of U. dioica (100 mg/kg/day) IP for the first 5 days and an injection of streptozotocin (80 mg/kg) on the 6th day. After 5 weeks of study all the rats were sacrificed and coronal sections were taken from the dorsal hippocampal formation of the right cerebral hemispheres and stained with cresyl violet. The area densities of the granule cells were measured and compared in the four groups. The density was lower in the diabetic rats compared with the controls (p > 0.05). The preventive group showed lower cell density than the controls (p > 0.05). The densities in the treated rats were higher than in the diabetic rats (p > 0.05). Furthermore, the control and treated rats showed similar densities (p > 0.05). It seems that U. dioica extract can help compensate for granule cell loss in the diabetic rat dentate gyrus, which can ameliorate cognitive impairment in diabetes. However, preventive use of the extract showed no significant benefit.

  13. Lipid Droplet Formation in HeLa Cervical Cancer Cells Depends on Cell Density and the Concentration of Exogenous Unsaturated Fatty Acids.

    Science.gov (United States)

    Guštin, Ema; Jarc, Eva; Kump, Ana; Petan, Toni

    2017-09-01

    Cytosolic lipid droplets (LDs) store excess fatty acids (FAs) in the form of neutral lipids and prevent starvation-induced cancer cell death. Here we studied the ability of mono- and polyunsaturated FAs to affect LD formation and survival in HeLa cervical cancer cells. We found that the LD content in HeLa cells increases with cell density, but it decreases in MDA-MB-231 breast cancer cells. Exogenously-added unsaturated FAs, including oleic (OA), linoleic (LA), arachidonic (AA), eicosapentaenoic (EPA) and docosahexaenoic acid (DHA) displayed a similar ability to alter LD formation in HeLa cells. There was a dual, concentration-dependent effect on neutral lipid accumulation: low micromolar concentrations of LA, AA and DHA reduced, while all FAs induced LD formation at higher concentrations. In serum starved He-La cells, OA stimulated LD formation, but, contrary to expectations, it promoted cell death. Our results reveal a link between cell population density and LD formation in HeLa cells and show that unsaturated FAs may both suppress or stimulate LD formation. This dynamic regulation of LD content must be accounted for when studying the effects of lipids and lipid metabolism-targeting drugs on LD metabolism in HeLa cells.

  14. Hypostatic jammed packings of frictionless nonspherical particles

    Science.gov (United States)

    VanderWerf, Kyle; Jin, Weiwei; Shattuck, Mark D.; O'Hern, Corey S.

    2018-01-01

    We perform computational studies of static packings of a variety of nonspherical particles including circulo-lines, circulo-polygons, ellipses, asymmetric dimers, dumbbells, and others to determine which shapes form packings with fewer contacts than degrees of freedom (hypostatic packings) and which have equal numbers of contacts and degrees of freedom (isostatic packings), and to understand why hypostatic packings of nonspherical particles can be mechanically stable despite having fewer contacts than that predicted from naive constraint counting. To generate highly accurate force- and torque-balanced packings of circulo-lines and cir-polygons, we developed an interparticle potential that gives continuous forces and torques as a function of the particle coordinates. We show that the packing fraction and coordination number at jamming onset obey a masterlike form for all of the nonspherical particle packings we studied when plotted versus the particle asphericity A , which is proportional to the ratio of the squared perimeter to the area of the particle. Further, the eigenvalue spectra of the dynamical matrix for packings of different particle shapes collapse when plotted at the same A . For hypostatic packings of nonspherical particles, we verify that the number of "quartic" modes along which the potential energy increases as the fourth power of the perturbation amplitude matches the number of missing contacts relative to the isostatic value. We show that the fourth derivatives of the total potential energy in the directions of the quartic modes remain nonzero as the pressure of the packings is decreased to zero. In addition, we calculate the principal curvatures of the inequality constraints for each contact in circulo-line packings and identify specific types of contacts with inequality constraints that possess convex curvature. These contacts can constrain multiple degrees of freedom and allow hypostatic packings of nonspherical particles to be mechanically

  15. Magnetic Resonance Imaging Detection of Tumor Cells by Targeting Low-Density Lipoprotein Receptors with Gd-Loaded Low-Density Lipoprotein Particles

    Directory of Open Access Journals (Sweden)

    Simonetta Geninatti Crich

    2007-12-01

    Full Text Available Gd-DO3A-diph and Gd-AAZTAC17 are lipophilic magnetic resonance imaging (MRI agents that display high affinity for low-density lipoprotein (LDL particles. However, on binding to LDL, Gd-DO3A-diph shows a decreased hydration that results in a lower enhancement of water proton relaxation rate. Conversely, GdAAZTAC17 displays a strong relaxation enhancement at the imaging fields. Each LDL particle can load up to 100 and 400 UNITS of Gd-DO3A-diph and Gd-AAZTAC17, respectively. Their LDL adducts are taken up by human hepatoblastoma G2 (HepG2 and melanoma B16 tumor cells when added to the incubation medium. T, measurements of the labeled cells indicate that Gd-AAZTAC17 is significantly more efficient than Gd-DO3A-diph. Furthermore, it has been found that HepG2 hepatoma cells can internalize higher amounts of Gd-AAZTAC17 than B16 cells and the involvement of LDL receptors (LDLRs has been demonstrated in competition assays with free LDL. Gd-AAZTAC17/LDL adduct proved to be an efficient probe in the magnetic resonance (MR visualization of subcutaneous tumors in animal models obtained by injecting B16 melanoma cells into the right flank of mice. Finally, confocal microscopy validation of the distribution of LDL-based probes in the tumor has been obtained by doping the Gd-AAZTAC17/LDL adduct with a fluorescent phospholipid moiety.

  16. Mathematical modeling of high-rate Anammox UASB reactor based on granular packing patterns

    International Nuclear Information System (INIS)

    Tang, Chong-Jian; He, Rui; Zheng, Ping; Chai, Li-Yuan; Min, Xiao-Bo

    2013-01-01

    Highlights: ► A novel model was conducted to estimate volumetric nitrogen conversion rates. ► The packing patterns of the granules in Anammox reactor are investigated. ► The simple cubic packing pattern was simulated in high-rate Anammox UASB reactor. ► Operational strategies concerning sludge concentration were proposed by the modeling. -- Abstract: A novel mathematical model was developed to estimate the volumetric nitrogen conversion rates of a high-rate Anammox UASB reactor based on the packing patterns of granular sludge. A series of relationships among granular packing density, sludge concentration, hydraulic retention time and volumetric conversion rate were constructed to correlate Anammox reactor performance with granular packing patterns. It was suggested that the Anammox granules packed as the equivalent simple cubic pattern in high-rate UASB reactor with packing density of 50–55%, which not only accommodated a high concentration of sludge inside the reactor, but also provided large pore volume, thus prolonging the actual substrate conversion time. Results also indicated that it was necessary to improve Anammox reactor performance by enhancing substrate loading when sludge concentration was higher than 37.8 gVSS/L. The established model was carefully calibrated and verified, and it well simulated the performance of granule-based high-rate Anammox UASB reactor

  17. Mathematical modeling of high-rate Anammox UASB reactor based on granular packing patterns

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Chong-Jian, E-mail: chjtangzju@yahoo.com.cn [Department of Environmental Engineering, School of Metallurgical Science and Engineering, Central South University, Changsha 410083 (China); National Engineering Research Center for Control and Treatment of Heavy Metal Pollution, Changsha 410083 (China); He, Rui; Zheng, Ping [Department of Environmental Engineering, Zhejiang University, Zijingang Campus, Hangzhou 310058 (China); Chai, Li-Yuan; Min, Xiao-Bo [Department of Environmental Engineering, School of Metallurgical Science and Engineering, Central South University, Changsha 410083 (China); National Engineering Research Center for Control and Treatment of Heavy Metal Pollution, Changsha 410083 (China)

    2013-04-15

    Highlights: ► A novel model was conducted to estimate volumetric nitrogen conversion rates. ► The packing patterns of the granules in Anammox reactor are investigated. ► The simple cubic packing pattern was simulated in high-rate Anammox UASB reactor. ► Operational strategies concerning sludge concentration were proposed by the modeling. -- Abstract: A novel mathematical model was developed to estimate the volumetric nitrogen conversion rates of a high-rate Anammox UASB reactor based on the packing patterns of granular sludge. A series of relationships among granular packing density, sludge concentration, hydraulic retention time and volumetric conversion rate were constructed to correlate Anammox reactor performance with granular packing patterns. It was suggested that the Anammox granules packed as the equivalent simple cubic pattern in high-rate UASB reactor with packing density of 50–55%, which not only accommodated a high concentration of sludge inside the reactor, but also provided large pore volume, thus prolonging the actual substrate conversion time. Results also indicated that it was necessary to improve Anammox reactor performance by enhancing substrate loading when sludge concentration was higher than 37.8 gVSS/L. The established model was carefully calibrated and verified, and it well simulated the performance of granule-based high-rate Anammox UASB reactor.

  18. Molecular packing in 1-hexanol-DMPC bilayers studied by molecular dynamics simulation

    DEFF Research Database (Denmark)

    Pedersen, U.R.; Peters, Günther H.j.; Westh, P.

    2007-01-01

    The structure and molecular packing density of a “mismatched” solute, 1-hexanol, in lipid membranes of dimyristoyl phosphatidylcholine (DMPC) was studied by molecular dynamics simulations. We found that the average location and orientation of the hexanol molecules matched earlier experimental dat....... The average lateral area per chain in this region expands, resulting in a looser packing density. The net effect in the core is a 2–3% decrease in density corresponding to a total volume increase of ∼ 14 cm3 mol−1 hexanol partitioned.......) is stretched by about 4%. Concomitantly, the average lateral area per chain decreases and these two effects compensate so that the overall packing density in the outer region, where the hexanol molecules are located, remains practically constant. The core of the bilayer (C9–C13) is slightly thinned...

  19. The “Theoreticals” Pack

    CERN Multimedia

    CERN Bulletin

    2011-01-01

    The Particle Zoo is a colourful set of hand-made soft toys representing the particles in the Standard Model and beyond. It includes a “theoreticals” pack where you can find yet undiscovered particles: the best-selling Higgs boson, the graviton, the tachyon, and dark matter. Supersymmetric particle soft toys are also available on demand. But what would happen to the zoo if Nature had prepared some unexpected surprises? Julie Peasley, the zookeeper, is ready to sew new smiling faces…   The "Theoreticals" pack in the Particle Zoo. There is only one place in the world where you can buy a smiling Higgs boson and it’s not at CERN, although this is where scientists hope to observe it. The blue star-shaped particle is the best seller of Julie Peasley’s Particle Zoo – a collection of tens of soft toys representing all sorts of particles, including composite and decaying particles.  Over the years Julie’s zoo ...

  20. Fast searching in packed strings

    DEFF Research Database (Denmark)

    Bille, Philip

    2011-01-01

    Given strings P and Q the (exact) string matching problem is to find all positions of substrings in Q matching P. The classical Knuth–Morris–Pratt algorithm [SIAM J. Comput. 6 (2) (1977) 323–350] solves the string matching problem in linear time which is optimal if we can only read one character...... at the time. However, most strings are stored in a computer in a packed representation with several characters in a single word, giving us the opportunity to read multiple characters simultaneously. In this paper we study the worst-case complexity of string matching on strings given in packed representation....... Let m⩽n be the lengths P and Q, respectively, and let σ denote the size of the alphabet. On a standard unit-cost word-RAM with logarithmic word size we present an algorithm using timeO(nlogσn+m+occ). Here occ is the number of occurrences of P in Q. For m=o(n) this improves the O(n) bound of the Knuth...

  1. High Energy Density Li-ion Cells for EV’s Based on Novel, High Voltage Cathode Material Systems

    Energy Technology Data Exchange (ETDEWEB)

    Kepler, Keith [Farasis Energy Inc; Slater, Michael [Farasis Energy Inc

    2018-03-14

    This Li-ion cell technology development project had three objectives: to develop advanced electrode materials and cell components to enable stable high-voltage operation; to design and demonstrate a Li-ion cell using these materials that meets the PHEV40 performance targets; and to design and demonstrate a Li-ion cell using these materials that meets the EV performance targets. The major challenge to creating stable high energy cells with long cycle life is system integration. Although materials that can give high energy cells are known, stabilizing them towards long-term cycling in the presence of other novel cell components is a major challenge. The major technical barriers addressed by this work include low cathode specific energy, poor electrolyte stability during high voltage operation, and insufficient capacity retention during deep discharge for Si-containing anodes. Through the course of this project, Farasis was able to improve capacity retention of NCM materials for 4.4+ V operation, through both surface treatment and bulk-doping approaches. Other material advances include increased rate capability and of HE-NCM materials through novel synthesis approach, doubling the relative capacity at 1C over materials synthesized using standard methods. Silicon active materials proved challenging throughout the project and ultimately were the limiting factor in the energy density vs. cycle life trade off. By avoiding silicon anodes for the lower energy PHEV design, we manufactured cells with intermediate energy density and long cycle life under high voltage operation for PHEV applications. Cells with high energy density for EV applications were manufactured targeting a 300 Wh/kg design and were able to achieve > 200 cycles.

  2. Sensitivity of energy-packed compounds based on superfine and nanoporous silicon to pulsed electrical treatments

    Energy Technology Data Exchange (ETDEWEB)

    Zegrya, G. G. [Russian Academy of Sciences, Ioffe Physical–Technical Institute (Russian Federation); Savenkov, G. G. [Saint-Petersburg State Engineering Institute (Technical University) (Russian Federation); Morozov, V. A. [Saint-Petersburg State University (Russian Federation); Zegrya, A. G.; Ulin, N. V., E-mail: Ulin@mail.ioffe.ru; Ulin, V. P. [Russian Academy of Sciences, Ioffe Physical–Technical Institute (Russian Federation); Lukin, A. A. [Saint-Petersburg State Engineering Institute (Technical University) (Russian Federation); Bragin, V. A.; Oskin, I. A. [AO Scientific Production Association Poisk (Russian Federation); Mikhailov, Yu. M. [Russian Academy of Sciences, Institute of Problems of Chemical Physics (Russian Federation)

    2017-04-15

    The sensitivity of an energy-packed compound based on nanoporous silicon and calcium perchlorate to a high-current electron beam is studied. The initiation of explosive transformations in a mixture of potassium picrate with a highly dispersed powder of boron-doped silicon by means of a high-voltage discharge is examined. It is shown that explosive transformation modes (combustion and explosion) appear in the energy-packed compound under study upon its treatment with an electron beam. A relationship is established between the explosive transformation modes and the density of the energy-packed compound and between the breakdown (initiation) voltage and the mass fraction of the silicon powder.

  3. The effect of contrast medium SonoVue® on the electric charge density of blood cells.

    Science.gov (United States)

    Petelska, Aneta D; Janica, Jacek R; Kotynska, Joanna; Łebkowska, Urszula; Figaszewski, Zbigniew A

    2012-01-01

    The effect of contrast medium SonoVue® on the electric charge density of blood cells (erythrocytes and thrombocytes) was measured using a microelectrophoretic method. We examined the effect of adsorbed H⁺ and OH⁻ ions on the surface charge of erythrocytes or thrombocytes. Surface charge density values were determined from electrophoretic mobility measurements of blood cells performed at various pH levels. The interaction between solution ions and the erythrocyte's or thrombocyte's surface was described by a four-component equilibrium model. The agreement between the experimental and theoretical charge variation curves of the erythrocytes and thrombocytes was good at pH 2-9. The deviation observed at a higher pH may be caused by disregarding interactions between the functional groups of blood cells.

  4. Management System for Large Li-Ion Battery Packs with a New Adaptive Multistage Charging Method

    Directory of Open Access Journals (Sweden)

    Ricardo Velho

    2017-05-01

    Full Text Available Among the wide diversity of existing technologically mature batteries, lithium-ion (Li-ion batteries have become popular because of their longevity, high energy density, high efficiency and lack of memory effect. Differential charging of cells with age has turned balancing management systems into an important research subject. This paper proposes a new battery management system (BMS to improve the capacity usage and lifespan of large Li-ion battery packs and a new charging algorithm based on the traditional multistage method. The main advantages of the proposed system are its versatility and ability to implement different charging and balancing methods in a very accessible way. The combination of charging methods with balancing methods represents an evolution when compared with other works in the literature.

  5. A novel approach of battery pack state of health estimation using artificial intelligence optimization algorithm

    Science.gov (United States)

    Zhang, Xu; Wang, Yujie; Liu, Chang; Chen, Zonghai

    2018-02-01

    An accurate battery pack state of health (SOH) estimation is important to characterize the dynamic responses of battery pack and ensure the battery work with safety and reliability. However, the different performances in battery discharge/charge characteristics and working conditions in battery pack make the battery pack SOH estimation difficult. In this paper, the battery pack SOH is defined as the change of battery pack maximum energy storage. It contains all the cells' information including battery capacity, the relationship between state of charge (SOC) and open circuit voltage (OCV), and battery inconsistency. To predict the battery pack SOH, the method of particle swarm optimization-genetic algorithm is applied in battery pack model parameters identification. Based on the results, a particle filter is employed in battery SOC and OCV estimation to avoid the noise influence occurring in battery terminal voltage measurement and current drift. Moreover, a recursive least square method is used to update cells' capacity. Finally, the proposed method is verified by the profiles of New European Driving Cycle and dynamic test profiles. The experimental results indicate that the proposed method can estimate the battery states with high accuracy for actual operation. In addition, the factors affecting the change of SOH is analyzed.

  6. Determination of Charge-Carrier Mobility in Disordered Thin-Film Solar Cells as a Function of Current Density

    Science.gov (United States)

    Mäckel, Helmut; MacKenzie, Roderick C. I.

    2018-03-01

    Charge-carrier mobility is a fundamental material parameter, which plays an important role in determining solar-cell efficiency. The higher the mobility, the less time a charge carrier will spend in a device and the less likely it is that it will be lost to recombination. Despite the importance of this physical property, it is notoriously difficult to measure accurately in disordered thin-film solar cells under operating conditions. We, therefore, investigate a method previously proposed in the literature for the determination of mobility as a function of current density. The method is based on a simple analytical model that relates the mobility to carrier density and transport resistance. By revising the theoretical background of the method, we clearly demonstrate what type of mobility can be extracted (constant mobility or effective mobility of electrons and holes). We generalize the method to any combination of measurements that is able to determine the mean electron and hole carrier density, and the transport resistance at a given current density. We explore the robustness of the method by simulating typical organic solar-cell structures with a variety of physical properties, including unbalanced mobilities, unbalanced carrier densities, and for high or low carrier trapping rates. The simulations reveal that near VOC and JSC , the method fails due to the limitation of determining the transport resistance. However, away from these regions (and, importantly, around the maximum power point), the method can accurately determine charge-carrier mobility. In the presence of strong carrier trapping, the method overestimates the effective mobility due to an underestimation of the carrier density.

  7. Structured packing: an opportunity for energy savings

    International Nuclear Information System (INIS)

    Chavez T, R.H.; Guadarrama G, J.J.

    1996-01-01

    This work emphasizes the advantages about the use of structured packing. This type of packings allows by its geometry to reduce the processing time giving energy savings and throw down the production costs in several industries such as heavy water production plants, petrochemical industry and all industries involved with separation processes. There is a comparative results of energy consumption utilizing the structured vs. Raschig packings. (Author)

  8. Packing defects into ordered structures

    DEFF Research Database (Denmark)

    Bechstein, R.; Kristoffersen, Henrik Høgh; Vilhelmsen, L.B.

    2012-01-01

    We have studied vicinal TiO2(110) surfaces by high-resolution scanning tunneling microscopy and density functional theory calculations. On TiO2 surfaces characterized by a high density of ⟨11̅ 1⟩ steps, scanning tunneling microscopy reveals a high density of oxygen-deficient strandlike adstructures....... With the help of density functional theory calculations we develop a complete structural model for the entire strand and demonstrate these adstructures to be more stable than an equivalent amount of bulk defects such as Ti interstitials. We argue that strands can form particularly easy on stepped surfaces...

  9. Oxidized low-density lipoprotein contributes to atherogenesis via co-activation of macrophages and mast cells.

    Directory of Open Access Journals (Sweden)

    Chong Chen

    Full Text Available Oxidized low-density lipoprotein (OxLDL is a risk factor for atherosclerosis, due to its role in endothelial dysfunction and foam cell formation. Tissue-resident cells such as macrophages and mast cells release inflammatory mediators upon activation that in turn cause endothelial activation and monocyte adhesion. Two of these mediators are tumor necrosis factor (TNF-α, produced by macrophages, and histamine, produced by mast cells. Static and microfluidic flow experiments were conducted to determine the number of adherent monocytes on vascular endothelium activated by supernatants of oxLDL-treated macrophages and mast cells or directly by oxLDL. The expression of adhesion molecules on activated endothelial cells and the concentration of TNF-α and histamine in the supernatants were measured by flow cytometry and enzyme-linked immunosorbent assay, respectively. A low dose of oxLDL (8 μg/ml, below the threshold for the clinical presentation of coronary artery disease, was sufficient to activate both macrophages and mast cells and synergistically increase monocyte-endothelium adhesion via released TNF-α and histamine. The direct exposure of endothelial cells to a much higher dose of oxLDL (80 μg/ml had less effect on monocyte adhesion than the indirect activation via oxLDL-treated macrophages and mast cells. The results of this work indicate that the co-activation of macrophages and mast cells by oxLDL is an important mechanism for the endothelial dysfunction and atherogenesis. The observed synergistic effect suggests that both macrophages and mast cells play a significant role in early stages of atherosclerosis. Allergic patients with a lipid-rich diet may be at high risk for cardiovascular events due to high concentration of low-density lipoprotein and histamine in arterial vessel walls.

  10. Relationship between Malaria Parasitaemia and Packed Cell ...

    African Journals Online (AJOL)

    p<0.05) from those of non malaria infected subjects (35.9±3.28). Our study revealed that malaria is still a major public health problem and may be a contributory factor to morbidity, mortality, school absenteeism and poor academic performance ...

  11. Coupled electrochemical thermal modelling of a novel Li-ion battery pack thermal management system

    International Nuclear Information System (INIS)

    Basu, Suman; Hariharan, Krishnan S.; Kolake, Subramanya Mayya; Song, Taewon; Sohn, Dong Kee; Yeo, Taejung

    2016-01-01

    Highlights: • Three-dimensional electrochemical thermal model of Li-ion battery pack using computational fluid dynamics (CFD). • Novel pack design for compact liquid cooling based thermal management system. • Simple temperature estimation algorithm for the cells in the pack using the results from the model. • Sensitivity of the thermal performance to contact resistance has been investigated. - Abstract: Thermal management system is of critical importance for a Li-ion battery pack, as high performance and long battery pack life can be simultaneously achieved when operated within a narrow range of temperature around the room temperature. An efficient thermal management system is required to keep the battery temperature in this range, despite widely varying operating conditions. A novel liquid coolant based thermal management system, for 18,650 battery pack has been introduced herein. This system is designed to be compact and economical without compromising safety. A coupled three-dimensional (3D) electrochemical thermal model is constructed for the proposed Li-ion battery pack. The model is used to evaluate the effects of different operating conditions like coolant flow-rate and discharge current on the pack temperature. Contact resistance is found to have the strongest impact on the thermal performance of the pack. From the numerical solution, a simple and novel temperature correlation of predicting the temperatures of all the individual cells given the temperature measurement of one cell is devised and validated with experimental results. Such coefficients have great potential of reducing the sensor requirement and complexity in a large Li-ion battery pack, typical of an electric vehicle.

  12. A Breast Cell Atlas: Organelle analysis of the MDA-MB-231 cell line by density-gradient fractionation using isotopic marking and label-free analysis

    Directory of Open Access Journals (Sweden)

    Marianne Sandin

    2015-09-01

    Full Text Available Protein translocation between organelles in the cell is an important process that regulates many cellular functions. However, organelles can rarely be isolated to purity so several methods have been developed to analyse the fractions obtained by density gradient centrifugation. We present an analysis of the distribution of proteins amongst organelles in the human breast cell line, MDA-MB-231 using two approaches: an isotopic labelling and a label-free approach.

  13. Minimally packed phases in holography

    Energy Technology Data Exchange (ETDEWEB)

    Donos, Aristomenis [Centre for Particle Theory and Department of Mathematical Sciences, Durham University,South Rd., Durham, DH1 3LE (United Kingdom); Gauntlett, Jerome P. [Blackett Laboratory, Imperial College,Prince Consort Rd., London, SW7 2AZ (United Kingdom)

    2016-03-21

    We numerically construct asymptotically AdS black brane solutions of D=4 Einstein-Maxwell theory coupled to a pseudoscalar. The solutions are holographically dual to d=3 CFTs at finite chemical potential and in a constant magnetic field, which spontaneously break translation invariance leading to the spontaneous formation of abelian and momentum magnetisation currents flowing around the plaquettes of a periodic Bravais lattice. We analyse the three-dimensional moduli space of lattice solutions, which are generically oblique, and show, for a specific value of the magnetic field, that the free energy is minimised by the triangular lattice, associated with minimal packing of circles in the plane. We show that the average stress tensor for the thermodynamically preferred phase is that of a perfect fluid and that this result applies more generally to spontaneously generated periodic phases. The triangular structure persists at low temperatures indicating the existence of novel crystalline ground states.

  14. The role of cell body density in ruminant retina mechanics assessed by atomic force and Brillouin microscopy

    Science.gov (United States)

    Weber, Isabell P.; Yun, Seok Hyun; Scarcelli, Giuliano; Franze, Kristian

    2017-12-01

    Cells in the central nervous system (CNS) respond to the stiffness of their environment. CNS tissue is mechanically highly heterogeneous, thus providing motile cells with region-specific mechanical signals. While CNS mechanics has been measured with a variety of techniques, reported values of tissue stiffness vary greatly, and the morphological structures underlying spatial changes in tissue stiffness remain poorly understood. We here exploited two complementary techniques, contact-based atomic force microscopy and contact-free Brillouin microscopy, to determine the mechanical properties of ruminant retinae, which are built up by different tissue layers. As in all vertebrate retinae, layers of high cell body densities (‘nuclear layers’) alternate with layers of low cell body densities (‘plexiform layers’). Different tissue layers varied significantly in their mechanical properties, with the photoreceptor layer being the stiffest region of the retina, and the inner plexiform layer belonging to the softest regions. As both techniques yielded similar results, our measurements allowed us to calibrate the Brillouin microscopy measurements and convert the Brillouin shift into a quantitative assessment of elastic tissue stiffness with optical resolution. Similar as in the mouse spinal cord and the developing Xenopus brain, we found a strong correlation between nuclear densities and tissue stiffness. Hence, the cellular composition of retinae appears to strongly contribute to local tissue stiffness, and Brillouin microscopy shows a great potential for the application in vivo to measure the mechanical properties of transparent tissues.

  15. Evaluation of pulp and mortar to pack bitumen radioactive waste

    International Nuclear Information System (INIS)

    Gregorio, Marina da S.; Vieira, Vanessa M.; Tello, Cledola C.O.

    2013-01-01

    According to international experience, for the deposition of cement in surface repository, is necessary the use of cement mortar pastes to immobilize the product. Determining the most efficient folder or for the packed mortar, as well as its ideal formulation, is the goal of this study. To do various experiments with samples of cement paste and mortar, with presence of fluxing and / or clay were performed. Viscosity, density, setting time and compressive strength were evaluated. This study will be presented only the results found in testing of compressive strength to be an essential parameter in the transport, storage and disposal of the product. From the results found will be selected the best formulations for use in packed bitumen tailings from the National Radioactive Waste Repository

  16. Non-convex shape effects on the dense random packing properties of assembled rods

    Science.gov (United States)

    Meng, Lingyi; Wang, Chao; Yao, Xiaohu

    2018-01-01

    The packing of rod-like particles, which is common in physical and mathematical studies, has arisen in a variety of industrial applications. Elongation effect on the packing properties of rod-like particle has been well investigated. Besides that, rod-like particles can be easily deformed into a large amount of non-convex shapes by simply bending or assembling several particles, in which effects of non-convex deformations should also be concerned. In this work, the packing behaviors of particulate systems composed of various non-convex deformations of rod-like particles are numerically simulated via the analytical model and the relaxation algorithm. The packing configurations are further optimized using the Monte Carlo method to eliminate the local ordered structures. 8 shapes of non-convex particles including 2-dimensional and 3-dimensional particles are employed in the packing systems. Independent of aspect ratio, the dense random packing densities of identical assembled rods are up to 20% higher than those of spherocylinders and are less dependent from the specific particle shape. However, the coordination numbers of various non-convex particle packings are quite different. With a parameter of convex ratio defined, a packing composed of more non-convex particles will have a higher coordination number. This indicates that for more non-convex particle packings, there are more constraints and entanglements among neighboring particles, resulting in a more stable configuration. The nearest-neighbor contact to a centered particle in 3DX-shaped particle packings is quite different from those of other shapes, which can be identified from the location of the first peak in the radial distribution function. It is also the cause to the distinct disparities of estimated excluded volumes of non-convex particles simulated in this work.

  17. Cylinders out of a top hat: counts-in-cells for projected densities

    Science.gov (United States)

    Uhlemann, Cora; Pichon, Christophe; Codis, Sandrine; L'Huillier, Benjamin; Kim, Juhan; Bernardeau, Francis; Park, Changbom; Prunet, Simon

    2018-03-01

    Large deviation statistics is implemented to predict the statistics of cosmic densities in cylinders applicable to photometric surveys. It yields few percent accurate analytical predictions for the one-point probability distribution function (PDF) of densities in concentric or compensated cylinders; and also captures the density-dependence of their angular clustering (cylinder bias). All predictions are found to be in excellent agreement with the cosmological simulation Horizon Run 4 in the quasi-linear regime where standard perturbation theory normally breaks down. These results are combined with a simple local bias model that relates dark matter and tracer densities in cylinders and validated on simulated halo catalogues. This formalism can be used to probe cosmology with existing and upcoming photometric surveys like DES, Euclid or WFIRST containing billions of galaxies.

  18. A phenomenological force model of Li-ion battery packs for enhanced performance and health management

    Science.gov (United States)

    Oh, Ki-Yong; Epureanu, Bogdan I.

    2017-10-01

    A 1-D phenomenological force model of a Li-ion battery pack is proposed to enhance the control performance of Li-ion battery cells in pack conditions for efficient performance and health management. The force model accounts for multiple swelling sources under the operational environment of electric vehicles to predict swelling-induced forces in pack conditions, i.e. mechanically constrained. The proposed force model not only incorporates structural nonlinearities due to Li-ion intercalation swelling, but also separates the overall range of states of charge into three ranges to account for phase transitions. Moreover, an approach to study cell-to-cell variations in pack conditions is proposed with serial and parallel combinations of linear and nonlinear stiffness, which account for battery cells and other components in the battery pack. The model is shown not only to accurately estimate the reaction force caused by swelling as a function of the state of charge, battery temperature and environmental temperature, but also to account for cell-to-cell variations due to temperature variations, SOC differences, and local degradation in a wide range of operational conditions of electric vehicles. Considering that the force model of Li-ion battery packs can account for many possible situations in actual operation, the proposed approach and model offer potential utility for the enhancement of current battery management systems and power management strategies.

  19. Packing Optimization of an Intentionally Stratified Sorbent Bed Containing Dissimilar Media Types

    Science.gov (United States)

    Kidd, Jessica; Guttromson, Jayleen; Holland, Nathan

    2010-01-01

    The Fire Cartridge is a packed bed air filter with two different and separate layers of media designed to provide respiratory protection from combustion products after a fire event on the International Space Station (ISS). The first layer of media is a carbon monoxide catalyst made from gold nanoparticles dispersed on iron oxide. The second layer of media is universal carbon, commonly used in commercial respirator filters. Each layer must be optimally packed to effectively remove contaminants from the air. Optimal packing is achieved by vibratory agitations. However, if post-packing movement of the media within the cartridge occurs, mixing of the bed layers, air voids, and channeling could cause preferential air flow and allow contaminants to pass. Several iterations of prototype fire cartridges were developed to reduce post-packing movement of the media within each layer (settling), and to prevent mixing of the two media types. Both types of movement of the media contribute to decreased fire cartridge performance. Each iteration of the fire cartridge design was tested to demonstrate mechanical loads required to cause detrimental movement within the bed, and resulting level of functionality of the media beds after movement was detected. In order to optimally pack each layer, vertical, horizontal, and orbital agitations were tested and a final packed bulk density was calculated for each method. Packed bulk density must be calculated for each lot of catalyst to accommodate variations in particle size, shape, and density. In addition, a physical divider sheet between each type of media was added within the fire cartridge design to further inhibit intermixing of the bed layers.

  20. The general packed column : an analytical solution

    NARCIS (Netherlands)

    Gielen, J.L.W.

    2000-01-01

    The transient behaviour of a packed column is considered. The column, uniformly packed on a macroscopic scale, is multi-structured on the microscopic level: the solid phase consists of particles, which may differ in incidence, shape or size, and other relevant physical properties. Transport in the

  1. Protein packing quality using Delaunay complexes

    DEFF Research Database (Denmark)

    Fonseca, Rasmus; Winter, Pawel; Karplus, Kevin

    2011-01-01

    A new method for estimating the packing quality of protein structures is presented. Atoms in high quality protein crystal structures are very uniformly distributed which is difficult to reproduce using structure prediction methods. Packing quality measures can therefore be used to assess structur...

  2. Does Post Septoplasty Nasal Packing Reduce Complications?

    Directory of Open Access Journals (Sweden)

    Bijan Naghibzadeh

    2011-01-01

    Full Text Available The main issues in nasal surgery are to stabilize the nose in the good position after surgery and preserve the cartilages and bones in the favorable situation and reduce the risk of deviation recurrence. Also it is necessary to avoid the synechia formation, nasal valve narrowing, hematoma and bleeding. Due to the above mentioned problems and in order to solve and minimize them nasal packing, nasal splint and nasal mold have been advised. Patients for whom the nasal packing used may faced to some problems like naso-pulmonary reflex, intractable pain, sleep disorder, post operation infection and very dangerous complication like toxic shock syndrome. We have two groups of patients and three surgeons (one of the surgeons used post operative nasal packing in his patients and the two others surgeons did not.Complications and morbidities were compared in these two groups. Comparing the two groups showed that the rate of complication and morbidities between these two groups were same and the differences were not valuable, except the pain and discomfort post operatively and at the time of its removal. Nasal packing has several risks for the patients while its effects are not studied. Septoplasty can be safely performed without postoperative nasal packing. Nasal packing had no main findings that compensated its usage. Septal suture is one of the procedures that can be used as alternative method to nasal packing. Therefore the nasal packing after septoplasty should be reserved for the patients with increased risk of bleeding.

  3. 7 CFR 982.11 - Pack.

    Science.gov (United States)

    2010-01-01

    ... 7 Agriculture 8 2010-01-01 2010-01-01 false Pack. 982.11 Section 982.11 Agriculture Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing Agreements and... according to size, internal quality, and external appearance and condition of hazelnuts packed in accordance...

  4. Development of an effective valve packing program

    Energy Technology Data Exchange (ETDEWEB)

    Hart, K.A.

    1996-12-01

    Current data now shows that graphite valve packing installed within the guidance of a controlled program produces not only reliable stem sealing but predictable running loads. By utilizing recent technological developments in valve performance monitoring for both MOV`s and AOV`s, valve packing performance can be enhanced while reducing maintenance costs. Once known, values are established for acceptable valve packing loads, the measurement of actual valve running loads via the current MOV/AOV diagnostic techniques can provide indication of future valve stem sealing problems, improper valve packing installation or identify the opportunity for valve packing program improvements. At times the full benefit of these advances in material and predictive technology remain under utilized due to simple past misconceptions associated with valve packing. This paper will explore the basis for these misconceptions, provide general insight into the current understanding of valve packing and demonstrate how with this new understanding and current valve diagnostic equipment the key aspects required to develop an effective, quality valve packing program fit together. The cost and operational benefits provided by this approach can be significant impact by the: elimination of periodic valve repacking, reduction of maintenance costs, benefits of leak-free valve operation, justification for reduced Post Maintenance Test Requirements, reduced radiation exposure, improved plant appearance.

  5. Development of an effective valve packing program

    International Nuclear Information System (INIS)

    Hart, K.A.

    1996-01-01

    Current data now shows that graphite valve packing installed within the guidance of a controlled program produces not only reliable stem sealing but predictable running loads. By utilizing recent technological developments in valve performance monitoring for both MOV's and AOV's, valve packing performance can be enhanced while reducing maintenance costs. Once known, values are established for acceptable valve packing loads, the measurement of actual valve running loads via the current MOV/AOV diagnostic techniques can provide indication of future valve stem sealing problems, improper valve packing installation or identify the opportunity for valve packing program improvements. At times the full benefit of these advances in material and predictive technology remain under utilized due to simple past misconceptions associated with valve packing. This paper will explore the basis for these misconceptions, provide general insight into the current understanding of valve packing and demonstrate how with this new understanding and current valve diagnostic equipment the key aspects required to develop an effective, quality valve packing program fit together. The cost and operational benefits provided by this approach can be significant impact by the: elimination of periodic valve repacking, reduction of maintenance costs, benefits of leak-free valve operation, justification for reduced Post Maintenance Test Requirements, reduced radiation exposure, improved plant appearance

  6. Improved taxation rate for bin packing games

    NARCIS (Netherlands)

    Kern, Walter; Qui, X.; Marchetti-Spaccamela, A.; Segal, M.

    2011-01-01

    A cooperative bin packing game is a $N$-person game, where the player set $N$ consists of $k$ bins of capacity 1 each and $n$ items of sizes $a_1,\\dots,a_n$. The value of a coalition of players is defined to be the maximum total size of items in the coalition that can be packed into the bins of the

  7. 7 CFR 989.9 - Packed raisins.

    Science.gov (United States)

    2010-01-01

    ... Regulations of the Department of Agriculture (Continued) AGRICULTURAL MARKETING SERVICE (Marketing Agreements... the marketing of raisins or in any container suitable or usable for such marketing. Raisins in the process of being packed or raisins which are partially packed shall be subject to the same requirements as...

  8. The role of surface charge density in cationic liposome-promoted dendritic cell maturation and vaccine-induced immune responses

    Science.gov (United States)

    Ma, Yifan; Zhuang, Yan; Xie, Xiaofang; Wang, Ce; Wang, Fei; Zhou, Dongmei; Zeng, Jianqiang; Cai, Lintao

    2011-05-01

    Cationic liposomes have emerged as a novel adjuvant and antigen delivery system to enhance vaccine efficacy. However, the role of surface charge density in cationic liposome-regulated immune responses has not yet been elucidated. In the present study, we prepared a series of DOTAP/DOPC cationic liposomes with different surface densities by incorporating varying amounts of DOPC (a neutral lipid) into DOTAP (a cationic lipid). The results showed that DOTAP/DOPC cationic liposome-regulated immune responses relied on the surface charge density, and might occur through ROS signaling. The liposomes with a relatively high charge density, such as DOTAP/DOPC 5 : 0 and 4 : 1 liposomes, potently enhanced dendritic cell maturation, ROS generaion, antigen uptake, as well as the production of OVA-specific IgG2a and IFN-γ. In contrast, low-charge liposomes, such as DOTAP/DOPC 1 : 4 liposome, failed to promote immune responses even at high concentrations, confirming that the immunoregulatory effect of cationic liposomes is mostly attributable to their surface charge density. Moreover, the DOTAP/DOPC 1 : 4 liposome suppressed anti-OVA antibody responses in vivo. Overall, maintaining an appropriate surface charge is crucial for optimizing the adjuvant effect of cationic liposomes and enhancing the efficacy of liposome-based vaccines.

  9. Induction of Chondrogenic Differentiation of Human Mesenchymal Stem Cells by Biomimetic Gold Nanoparticles with Tunable RGD Density.

    Science.gov (United States)

    Li, Jingchao; Li, Xiaomeng; Zhang, Jing; Kawazoe, Naoki; Chen, Guoping

    2017-07-01

    Nanostructured materials have drawn a broad attention for their applications in biomedical fields. Ligand-modified nanomaterials can well mimic the dynamic extracellular matrix (ECM) microenvironments to regulate cell functions and fates. Herein, ECM mimetic gold nanoparticles (Au NPs) with tunable surface arginine-glycine-aspartate (RGD) density are designed and synthesized to induce the chondrogenic differentiation of human mesenchymal stem cells (hMSCs). The biomimetic Au NPs with an average size of 40 nm shows good biocompatibility without affecting the cell proliferation in the studied concentration range. The RGD motifs on Au NPs surface facilitate cellular uptake of NPs into monolayer hMSCs through integrin-mediated endocytosis. The biomimetic NPs have a promotive effect on cartilaginous matrix production and marker gene expression in cell pellet culture, especially for the biomimetic Au NPs with high surface RGD density. This study provides a novel strategy for fabricating biomimetic NPs to regulate cell differentiation, which holds great potentials in tissue engineering and biomedical applications. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. High energy efficiency and high power density proton exchange membrane fuel cells: Electrode kinetics and mass transport

    Science.gov (United States)

    Srinivasan, Supramaniam; Velev, Omourtag A.; Parthasathy, Arvind; Manko, David J.; Appleby, A. John

    1991-01-01

    The development of proton exchange membrane (PEM) fuel cell power plants with high energy efficiencies and high power densities is gaining momentum because of the vital need of such high levels of performance for extraterrestrial (space, underwater) and terrestrial (power source for electric vehicles) applications. Since 1987, considerable progress has been made in achieving energy efficiencies of about 60 percent at a current density of 200 mA/sq cm and high power densities (greater than 1 W/sq cm) in PEM fuel cells with high (4 mg/sq cm) or low (0.4 mg/sq cm) platinum loadings in electrodes. The following areas are discussed: (1) methods to obtain these high levels of performance with low Pt loading electrodes - by proton conductor impregnation into electrodes, localization of Pt near front surface; (2) a novel microelectrode technique which yields electrode kinetic parameters for oxygen reduction and mass transport parameters; (3) demonstration of lack of water transport from anode to cathode; (4) modeling analysis of PEM fuel cell for comparison with experimental results and predicting further improvements in performance; and (5) recommendations of needed research and development for achieving the above goals.

  11. Transcriptome and proteome analysis of antibody-producing mouse myeloma NS0 cells cultivated at different cell densities in perfusion culture.

    Science.gov (United States)

    Krampe, Britta; Swiderek, Halina; Al-Rubeai, Mohamed

    2008-07-01

    A combined gene and protein expression profiling was performed to gain a deeper insight into the intracellular response of the antibody-producing GS-NS0 cell line in continuous perfusion culture. Growth rate, production rate, metabolic activity and viability declined with increasing cell density, dilution rate and time. Transcriptome and proteome analyses of cells at three different densities revealed 53 genes and 47 proteins as having significantly altered expression levels at HCD (high cell density). The results showed an increased up-regulation of genes/proteins involved in cellular energy production with increasing cell density. Furthermore, the intensified process triggered a cellular response to external stress stimuli, revealed by an overexpression of the genes/proteins implicated in cell-cycle arrest [e.g. Rb1 (retinoblastoma 1 gene) and Cdkn1b (cyclin-dependent kinase inhibitor 1B gene)] and in the induction of pro-apoptotic genes/proteins [e.g. Tnfrsf (tumour necrosis factor receptor superfamily gene), Nfkappa bia (gene coding for nuclear factor-kappaB inhibitor), HSP60 (heat-shock protein of molecular mass 60 kDa) and heterogeneous nuclear ribonucleoprotein K]. Interestingly, we observed a down-regulation of the transcription factor interferon regulatory factor 4 involved in the unfolded-protein-response process and protein disulfide-isomerase family members responsible for protein folding and assembly. Additionally, subunits of proteasome complex were highly expressed at HCD. Microarray, real-time quantitative reverse-transcription PCR and Western-blot analyses demonstrated a consistent trend of decrease in IgG heavy-chain level with increasing cell density. HSP60, which inhibits apoptosis by complexing with pro-apoptotic proteins such as Bax and Bak, was repressed at HCD. Overall, the data suggested that the balance among several factors involved in energy metabolism might be essential for fine-tuning the cell choice between survival and apoptosis

  12. Low Temperature, High Energy Density Micro Thin Film Solid Oxide Fuel Cell Project

    Data.gov (United States)

    National Aeronautics and Space Administration — A new type of solid oxide fuel cell based on thin film technology and ultra-thin electrolyte is being proposed to develop to realize major reductions in fuel cell...

  13. Mast Cells Density in Fibrotic Capsule of Enchondroma and Well-Differentiated Chondrosarcoma: A Method for Histopathologic Differentiation

    Directory of Open Access Journals (Sweden)

    Mohammad Javad Kharazi Fard

    2012-02-01

    Full Text Available Background: An enchondroma is a benign and a well-differentiated chondrosarcoma is an invasive chondroid tumor with high recurrence potential. In spite of biologic differences, these two tumors have very similar histopathologic appearance. It has been shown that the biologic nature of the connective tissue around benign and malignant tumors varies in the number of mast cells. The aim of this study was to study the histopathologic distinction of enchondroma and well-differentiated chondrosarcoma using the density of the mast cells in fibrotic capsule. Methods: Twelve enchondroma and 15 well-differentiated chondrosarcoma were collected from Pathology department of Cancer Institute and Central Pathology department of Imam Khomeini Hospital in Tehran. 3 micron paraffin embedded tissue sections were stained by toluidine blue for mast cells counting. Mast cells were counted in fibrous capsule of all cases. Mast cells counts were accomplished in 10 high power fields .The average number of mast cells in 10HPF was determined as an index for each lesion. Mann-Whitney U test was used for statistical analysis. Results: Mean index in enchondroma and well-differentiated chondrosarcoma groups were 0.1±0.12 and 0.31±0.33 respectively, showing a significant difference between number of mast cells in the fibrotic capsule in these two lesions (p=0.028. Comparison of the corresponding points in ROC curve, showed a cut-off point = 0.15, with positive predictive value of 61%, negative predictive value 71%, specificity of 33.3% and sensitivity of 66.7%, (p=0.025. Conclusion: Average density of the mast cells in the surrounding fibrotic capsules of enchondroma and well-differentiated chondrosarcoma along with other criterions, could be a beneficial factor for histologically differentiation between these two lesions.

  14. Identification of melanoma cells: a method based in mean variance of signatures via spectral densities.

    Science.gov (United States)

    Guerra-Rosas, Esperanza; Álvarez-Borrego, Josué; Angulo-Molina, Aracely

    2017-04-01

    In this paper a new methodology to detect and differentiate melanoma cells from normal cells through 1D-signatures averaged variances calculated with a binary mask is presented. The sample images were obtained from histological sections of mice melanoma tumor of 4 [Formula: see text] in thickness and contrasted with normal cells. The results show that melanoma cells present a well-defined range of averaged variances values obtained from the signatures in the four conditions used.

  15. Dysregulated B cell expression of RANKL and OPG correlates with loss of bone mineral density in HIV infection.

    Directory of Open Access Journals (Sweden)

    Kehmia Titanji

    2014-10-01

    Full Text Available HIV infection is associated with high rates of osteopenia and osteoporosis, but the mechanisms involved are unclear. We recently reported that bone loss in the HIV transgenic rat model was associated with upregulation of B cell expression of the key osteoclastogenic cytokine receptor-activator of NF-κB ligand (RANKL, compounded by a simultaneous decline in expression of its physiological moderator, osteoprotegerin (OPG. To clinically translate these findings we performed cross-sectional immuno-skeletal profiling of HIV-uninfected and antiretroviral therapy-naïve HIV-infected individuals. Bone resorption and osteopenia were significantly higher in HIV-infected individuals. B cell expression of RANKL was significantly increased, while B cell expression of OPG was significantly diminished, conditions favoring osteoclastic bone resorption. The B cell RANKL/OPG ratio correlated significantly with total hip and femoral neck bone mineral density (BMD, T- and/or Z-scores in HIV infected subjects, but revealed no association at the lumbar spine. B cell subset analyses revealed significant HIV-related increases in RANKL-expressing naïve, resting memory and exhausted tissue-like memory B cells. By contrast, the net B cell OPG decrease in HIV-infected individuals resulted from a significant decline in resting memory B cells, a population containing a high frequency of OPG-expressing cells, concurrent with a significant increase in exhausted tissue-like memory B cells, a population with a lower frequency of OPG-expressing cells. These data validate our pre-clinical findings of an immuno-centric mechanism for accelerated HIV-induced bone loss, aligned with B cell dysfunction.

  16. Dysregulated B Cell Expression of RANKL and OPG Correlates with Loss of Bone Mineral Density in HIV Infection

    Science.gov (United States)

    Titanji, Kehmia; Vunnava, Aswani; Sheth, Anandi N.; Delille, Cecile; Lennox, Jeffrey L.; Sanford, Sara E.; Foster, Antonina; Knezevic, Andrea; Easley, Kirk A.

    2014-01-01

    HIV infection is associated with high rates of osteopenia and osteoporosis, but the mechanisms involved are unclear. We recently reported that bone loss in the HIV transgenic rat model was associated with upregulation of B cell expression of the key osteoclastogenic cytokine receptor-activator of NF-κB ligand (RANKL), compounded by a simultaneous decline in expression of its physiological moderator, osteoprotegerin (OPG). To clinically translate these findings we performed cross-sectional immuno-skeletal profiling of HIV-uninfected and antiretroviral therapy-naïve HIV-infected individuals. Bone resorption and osteopenia were significantly higher in HIV-infected individuals. B cell expression of RANKL was significantly increased, while B cell expression of OPG was significantly diminished, conditions favoring osteoclastic bone resorption. The B cell RANKL/OPG ratio correlated significantly with total hip and femoral neck bone mineral density (BMD), T- and/or Z-scores in HIV infected subjects, but revealed no association at the lumbar spine. B cell subset analyses revealed significant HIV-related increases in RANKL-expressing naïve, resting memory and exhausted tissue-like memory B cells. By contrast, the net B cell OPG decrease in HIV-infected individuals resulted from a significant decline in resting memory B cells, a population containing a high frequency of OPG-expressing cells, concurrent with a significant increase in exhausted tissue-like memory B cells, a population with a lower frequency of OPG-expressing cells. These data validate our pre-clinical findings of an immuno-centric mechanism for accelerated HIV-induced bone loss, aligned with B cell dysfunction. PMID:25393853

  17. Mechanical Stimulation in Preventing Bone Density Loss in Patients Undergoing Donor Stem Cell Transplant

    Science.gov (United States)

    2012-07-05

    Accelerated Phase Chronic Myelogenous Leukemia; Adult Acute Lymphoblastic Leukemia in Remission; Adult Acute Myeloid Leukemia in Remission; Adult Acute Myeloid Leukemia With 11q23 (MLL) Abnormalities; Adult Acute Myeloid Leukemia With Del(5q); Adult Acute Myeloid Leukemia With Inv(16)(p13;q22); Adult Acute Myeloid Leukemia With t(15;17)(q22;q12); Adult Acute Myeloid Leukemia With t(16;16)(p13;q22); Adult Acute Myeloid Leukemia With t(8;21)(q22;q22); Atypical Chronic Myeloid Leukemia, BCR-ABL1 Negative; Blastic Phase Chronic Myelogenous Leukemia; Chronic Eosinophilic Leukemia; Chronic Myelomonocytic Leukemia; Chronic Neutrophilic Leukemia; Chronic Phase Chronic Myelogenous Leukemia; de Novo Myelodysplastic Syndromes; Disseminated Neuroblastoma; Extranodal Marginal Zone B-cell Lymphoma of Mucosa-associated Lymphoid Tissue; Myelodysplastic/Myeloproliferative Neoplasm, Unclassifiable; Nodal Marginal Zone B-cell Lymphoma; Noncontiguous Stage II Adult Burkitt Lymphoma; Noncontiguous Stage II Adult Diffuse Large Cell Lymphoma; Noncontiguous Stage II Adult Diffuse Mixed Cell Lymphoma; Noncontiguous Stage II Adult Diffuse Small Cleaved Cell Lymphoma; Noncontiguous Stage II Adult Immunoblastic Large Cell Lymphoma; Noncontiguous Stage II Adult Lymphoblastic Lymphoma; Noncontiguous Stage II Grade 1 Follicular Lymphoma; Noncontiguous Stage II Grade 2 Follicular Lymphoma; Noncontiguous Stage II Grade 3 Follicular Lymphoma; Noncontiguous Stage II Mantle Cell Lymphoma; Noncontiguous Stage II Marginal Zone Lymphoma; Noncontiguous Stage II Small Lymphocytic Lymphoma; Plasma Cell Neoplasm; Poor Prognosis Metastatic Gestational Trophoblastic Tumor; Previously Treated Myelodysplastic Syndromes; Primary Myelofibrosis; Prolymphocytic Leukemia; Recurrent Adult Acute Lymphoblastic Leukemia; Recurrent Adult Acute Myeloid Leukemia; Recurrent Adult Burkitt Lymphoma; Recurrent Adult Diffuse Large Cell Lymphoma; Recurrent Adult Diffuse Mixed Cell Lymphoma; Recurrent Adult Diffuse Small Cleaved

  18. [THE EFFECT OF SATINS: ACTIVATION OF LIPOLYSIS AND ABSORPTION BY INSULIN-DEPENDED CELLS LIPOPROTEINS OF VERY LOW DENSITY, INCREASING OF BIO-AVAILABILITY OF POLYENOIC FATTY ACIDS AND DECREASING OF CHOLESTEROL OF LIPOPROTEINS OF LOW DENSITY].

    Science.gov (United States)

    Titov, V N; Malyshev, P P; Amelyushkina, V A; Aripovsky, A V; Smirnov, G P; Polevaya, T Yu; Kabo, S I; Kukhartchuk, V V

    2015-10-01

    The Russian cardiologic R&D production complex of Minzdrav of Russia, 121552 Moscow, Russia The statins are synthetic xenobiotics alien to animal cells. They are unlikely capable to manifest pleiotropic effect. It is feasible to evaluate effect of statins by stages: a) initially a specific inhibition of synthesis of cholesterol alcohol; b) further indirect activation of hydrolysis of triglycerides in lipoproteins of very low density; c) nonspecific activation of cells' receptor absorption of palmitic and oleic lipoproteins of very low density and then d) linoleic and linolenic lipoproteins of low density with all polyenoic fatty acids. On balance, statins activate absorption ofpolyenoic fatty acids by cells. Just they manifest physiological, specific pleiotropic effect. The statins inhibit synthesis of pool of cholesterol alcohol-lipoproteins of very low density condensed between phosphatidylcholines in polar mono-layer phosphatidylcholines+cholesterol alcohol on surface oftriglycerides. The low permeability of mono-layer separates substrate-triglycerides in lipoproteins of very low density and post-heparin lipoprotein lipase in hydrophilic blood plasma. The higher is ratio cholesterol alcohol/phosphatidylcholines in mono-layer of lipoproteins of very low density the slower is lipolysis, formation of ligand lipoproteins of very low density and their absorption by cells under apoB-100-endocytosis. The statins normalize hyperlipemia by force of a) activation of absorption oflipoproteins of very low density by insulin-depended cells and b) activation of absorption of lipoproteins of low density by all cells, increasing of bio-availability of polyenoic fatty acids, activation of apoB-100-endocytosis. The limitation in food of content of palmitic saturated fatty acid and increasing of content of ω-3 polyenoic fatty acids improve "bio-availability" of polyenoic fatty acids and their absorption by cells and also decreases cholesterol alcohol/phosphatidylcholines and

  19. Stability of the phenotypic reversion of x-ray transformed C3H/10T1/2 cells depends on cellular proliferation after subcultivation at low cell density

    International Nuclear Information System (INIS)

    Brouty-Boye, D.; Gresser, I.; Bandu, M.T.

    1982-01-01

    Reversion from the transformed to the non-transformed phenotype could be obtained by seeding X-ray transformed C3H/10T1/2 cells at low cell density. Cloned revertant cells of varying degrees of reversion were obtained depending on the time they were isolated after one subculture at low cell density. Most of the revertants isolated 7 and 10 days after seeding at very low cell density eventually returned to the transformed phenotype when passaged serially at high cell density. In contrast, 25-35% of the revertants isolated 17-20 days after seeding at low cell density maintained the non-transformed phenotype despite subsequent serial passages at high cell density. The finding that there was a direct relationship between the time during which transformed cells seeded at low cell density multiplied and the number of stable revertant clones obtained, suggests the possibility that reversion from the transformed to the non-transformed phenotype may be a multistep process. Revertant cells displayed a chromosomal pattern characteristic of the transformed cells rather than that of the parental non-transformed 10T1/2 cells. (author)

  20. Hawking Colloquium Packed CERN Auditoriums

    CERN Document Server

    2006-01-01

    Stephen Hawking's week long visit to CERN included an 'exceptional CERN colloquium' which filled six auditoriums. Stephen Hawking during his visit to the ATLAS experiment. Stephen Hawking, Lucasian Professor of Cambridge University, visited the Theory Unit of the Physics Department from 24 September to 1 October 2006. As part of his visit, he gave two lectures in the main auditorium - a theoretical seminar on 'The Semi-Classical Birth of The Universe', attended by about 120 specialists; and a colloquium titled 'The Origin of The Universe'. As a key public figure in theoretical physics, his presence was eagerly awaited on both occasions. Those who wanted to attend the colloquium had to arrive early and be equipped with plenty of patience. An hour before it was due to begin, the 400 capacity of the main auditorium was already full. The lecture, simultaneously broadcast to five other fully packed CERN auditoriums, was attended by an estimated total of 850. Stephen Hawking attracted a large CERN crowd, filling ...

  1. Bi-Cell Unit for Fuel Cell.

    Science.gov (United States)

    The patent concerns a bi-cell unit for a fuel cell . The bi-cell unit is comprised of two electrode packs. Each of the electrode packs includes an...invention relates in general to a bi-cell unit for a fuel cell and in particular, to a bi-cell unit for a hydrazine-air fuel cell .

  2. On spherical symmetry modelling of DNA packing within bacteriophage heads according to small angle scattering data

    International Nuclear Information System (INIS)

    Dembo, A.T.; Tikhonychev, V.V.

    1983-01-01

    Spherical symmetry models were used for interpretation of X-ray small angle scattering curves of bacteriophage solutions. These models were built of concentric spherical layers of finite thickness with various scattering densities. The attention was attached to the ripple intensity of DNA packing maximum. In model calculations such parameters as external radius, scattering densities, number of DNA-imitating layers and internal radii were changed. The results show that the fine structure of DNA packing maximum depends on the overall shape and size of the region occupied by DNA inside the bacteriophage head. (author)

  3. Material selection and assembly method of battery pack for compact electric vehicle

    Science.gov (United States)

    Lewchalermwong, N.; Masomtob, M.; Lailuck, V.; Charoenphonphanich, C.

    2018-01-01

    Battery packs become the key component in electric vehicles (EVs). The main costs of which are battery cells and assembling processes. The battery cell is indeed priced from battery manufacturers while the assembling cost is dependent on battery pack designs. Battery pack designers need overall cost as cheap as possible, but it still requires high performance and more safety. Material selection and assembly method as well as component design are very important to determine the cost-effectiveness of battery modules and battery packs. Therefore, this work presents Decision Matrix, which can aid in the decision-making process of component materials and assembly methods for a battery module design and a battery pack design. The aim of this study is to take the advantage of incorporating Architecture Analysis method into decision matrix methods by capturing best practices for conducting design architecture analysis in full account of key design components critical to ensure efficient and effective development of the designs. The methodology also considers the impacts of choice-alternatives along multiple dimensions. Various alternatives for materials and assembly techniques of battery pack are evaluated, and some sample costs are presented. Due to many components in the battery pack, only seven components which are positive busbar and Z busbar are represented in this paper for using decision matrix methods.

  4. Life Prediction of Large Lithium-Ion Battery Packs with Active and Passive Balancing

    Energy Technology Data Exchange (ETDEWEB)

    Shi, Ying [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Smith, Kandler A [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Zane, Regan [Utah State University; Anderson, Dyche [Ford Motor Company

    2017-07-03

    Lithium-ion battery packs take a major part of large-scale stationary energy storage systems. One challenge in reducing battery pack cost is to reduce pack size without compromising pack service performance and lifespan. Prognostic life model can be a powerful tool to handle the state of health (SOH) estimate and enable active life balancing strategy to reduce cell imbalance and extend pack life. This work proposed a life model using both empirical and physical-based approaches. The life model described the compounding effect of different degradations on the entire cell with an empirical model. Then its lower-level submodels considered the complex physical links between testing statistics (state of charge level, C-rate level, duty cycles, etc.) and the degradation reaction rates with respect to specific aging mechanisms. The hybrid approach made the life model generic, robust and stable regardless of battery chemistry and application usage. The model was validated with a custom pack with both passive and active balancing systems implemented, which created four different aging paths in the pack. The life model successfully captured the aging trajectories of all four paths. The life model prediction errors on capacity fade and resistance growth were within +/-3% and +/-5% of the experiment measurements.

  5. Quantitative Imaging of Cell Membrane-associated Effective Mass Density Using Photonic Crystal Enhanced Microscopy (PCEM)

    Science.gov (United States)

    Zhuo, Yue; Choi, Ji Sun; Marin, Thibault; Yu, Hojeong; Harley, Brendan A.; Cunningham, Brian T.

    2017-01-01

    Adhesion is a critical cellular process that contributes to migration, apoptosis, differentiation, and division. It is followed by the redistribution of cellular materials at the cell membrane or at the cell-surface interface for cells interacting with surfaces, such as basement membranes. Dynamic and quantitative tracking of changes in cell adhesion mass redistribution is challenging because cells are rapidly moving, inhomogeneous, and nonequilibrium objects, whose physical and mechanical properties are difficult to measure or predict. Here, we report a novel biosensor based microscopy approach termed Photonic Crystal Enhanced Microscopy (PCEM) that enables the movement of cellular materials at the plasma membrane of individual live cells to be dynamically monitored and quantitatively imaged. PCEM utilizes a photonic crystal biosensor surface, which can be coated with arbitrary extracellular matrix materials to facilitate cellular interactions, within a modified brightfield microscope with a low intensity non-coherent light source. Benefiting from the high sensitivity, narrow resonance peak, and tight spatial confinement of the evanescent field atop the photonic crystal biosensor, PCEM enables label-free live cell imaging with high sensitivity and high lateral and axial spatial-resolution, thereby allowing dynamic adhesion phenotyping of single cells without the use of fluorescent tags or stains. We apply PCEM to investigate adhesion and the early stage migration of different types of stem cells and cancer cells. By applying image processing algorithms to analyze the complex spatiotemporal information generated by PCEM, we offer insight into how the plasma membrane of anchorage dependent cells is dynamically organized during cell adhesion. The imaging and analysis results presented here provide a new tool for biologists to gain a deeper understanding of the fundamental mechanisms involved with cell adhesion and concurrent or subsequent migration events. PMID

  6. Effect of Monosodium Glutamate and L-Carnitine on Density and Structure of Granular Cells of Cerebellum in Rat

    Directory of Open Access Journals (Sweden)

    Mojdeh Fatahzadeh

    2018-04-01

    Full Text Available Abstract Background: Monosodium glutamate (MSG is a widely-used flavor enhancer and stabilizer in ready-made or packaged foods. The excessive use of MSG has been shown to increase oxidative stress in different regions of the brain. In this study, the neuroprotective effect of L-carnitine was investigated against MSG intoxication in granular cell of cerebellum in rats. Materials and Methods: 48 adult male Wistar rats were randomly divided into 6 groups: the control, sham (normal saline treated, MSG (3%, L-Carnitine200, MSG+L-Carnitine100 and MSG+L-Carnitine200. After 30 days of treatment, through transcardialy perfusion, the rats were sacrificed and histopathological analyses were conducted on cerebellum. Results: The results indicated that the density of granular cells in cerebellar folium IV, V and VI of rats in the MSG group had significantly decreased in comparison to that of the control and sham groups. Furthermore, the MSG+L-Carnitine200 group showed the higher density of granular cells compared with the MSG group in the three folia. Conclusion: Treatment with L-Carnitine could protect the granular cells in cerebellum against MSG intoxication in rats.

  7. Quantifying protein densities on cell membranes using super-resolution optical fluctuation imaging

    Czech Academy of Sciences Publication Activity Database

    Lukeš, T.; Glatzová, Daniela; Kvíčalová, Zuzana; Levet, F.; Benda, Aleš; Letschert, S.; Sauer, M.; Brdička, Tomáš; Lasser, T.; Cebecauer, Marek

    2017-01-01

    Roč. 8, č. 1 (2017), č. článku 1731. ISSN 2041-1723 R&D Projects: GA ČR GA15-06989S Institutional support: RVO:61388955 ; RVO:68378050 Keywords : quantifying protein densities * membranes * single- molecule localization microscopy Subject RIV: CE - Biochemistry OBOR OECD: Biochemistry and molecular biology Impact factor: 12.124, year: 2016

  8. Effect of coating density on oxidation resistance and Cr vaporization from solid oxide fuel cell interconnects

    DEFF Research Database (Denmark)

    Talic, Belma; Falk-Windisch, Hannes; Venkatachalam, Vinothini

    2017-01-01

    •Protective action of dense and porous spinel coatings on Crofer 22 APU was compared. •Reduction and re-oxidation produces denser coatings than heat treating in air only. •Coating density has minor influence on oxidation resistance at 800 °C in air. •Dense coating resulted in three times lower Cr...

  9. Towards High Power Density Metal Supported Solid Oxide Fuel Cell for Mobile Applications

    DEFF Research Database (Denmark)

    Nielsen, Jimmi; Persson, Åsa Helen; Muhl, Thuy

    2017-01-01

    For use of metal supported SOFC in mobile applications it is important to reduce the thermal mass to enable fast start up, increase stack power density in terms of weight and volume and reduce costs. In the present study, we report on the effect of reducing the support layer thickness of 313 μm...

  10. Modelling of Packed Co Nanorods for Hard Magnetic Applications

    Directory of Open Access Journals (Sweden)

    Toson P.

    2014-07-01

    Full Text Available We present a numerical algorithm based on the bullet physics library to generate densely packed (39% - 41% structures of high-aspect-ratio nanorods for finite element micromagnetic simulations. The coercivities µ0Hc of the corresponding Cobalt nanorod structures vary between 0.50T and 0.67T, depending on the overall orientation of nanorods, which is in good agreement with experimental results. The simulations make it possible to estimate the coercivity loss due to incoherent reversal processes (27% as well as the gain due to shape anisotropy (59%. Our calculations show permanent magnets consisting of packed Co nanorods with an energy density product (BHmax of 83kJ/m3. We estimate that this value can be increased to 103kJ/m3 by increasing the packing density from 40% to 45%. Another way to optimize (BHmax is the usage of novel materials. By varying the anisotropy constant K1 and the saturation polarisation JS we found lower limits for these parameters to reach a certain energy density product. To increase (BHmax to 160 kJ/m3, K1 and JS have to be in the order of 450kJ/m3 and 2.25T, respectively. The thermal stability of this approach was verified by elastic band calculations. Cobalt nanorods with a diameter of 10nm and a height of 50nm are thermally stable at room temperature, but problematic at 900K. Doubling the nanorods' height to 100nm increases that limit considerably.

  11. Packing configuration performance for small stem diameters

    International Nuclear Information System (INIS)

    Aikin, J.A.; Spence, C.G.; Cumming, D.

    1997-01-01

    The extensive use of graphite packing and its excellent track record for large isolating valves in CANDU, Primary Heat Transfer (PHT) systems has resulted in an increased application of graphite packing on the conventional side. Many of these applications are in air operated valves (AOVs) where the packing sets are used on small stem diameters (<1 inch) with frequent short-cycling strokes (± 10% of full stroke). The direct application of the proven packing configurations for large isolated valves to control valve application has generated problems such as stiction, packing wear and, in isolated cases, stem stall. To address this issue, a test program was conducted at AECL, CRL by MED branch. The testing showed that by reconfiguring the packing sets and using PTFE wafers reductions in stem friction of 50% at ambient conditions, a 3 fold at hot conditions are achievable. The test program also demonstrated benefits gained in packing wear with different stem roughness finishes and the potential need to exercise small stems valves that see less than full stroke cycling. The paper describes the tests results and provides field support experience. (author)

  12. Development and performance measurement of micro-power pack using micro-gas turbine driven automotive alternators

    International Nuclear Information System (INIS)

    Sim, Kyuho; Koo, Bonjin; Kim, Chang Ho; Kim, Tae Ho

    2013-01-01

    Highlights: ► We develop micro-power pack using automotive alternator and micro-gas turbine. ► We measure rotordynamic and power generation performance of micro-power pack. ► Micro-power pack shows dramatic increases in mass and volumetric power densities. ► Test results assure feasibility of micro-power pack for electric vehicles. -- Abstract: This paper presents the development of a micro-power pack using automotive alternators powered by a micro-gas turbine (MGT) to recharge battery packs, in particular for electric vehicles (EVs). The thermodynamic efficiency for the MGT with the power turbine is estimated from a simple Brayton cycle analysis. The rotordynamic and power generation performance of the MGT driven alternator was measured during a series of experiments under electrical no-loading and loading conditions, and with belt-pulley and flexible bellows couplings. The flexible coupling showed superior rotordynamic and power generation performance than the belt coupling due to the enhanced alignment of the alternator rotor and the reduced mechanical frictions. Furthermore, the micro-power pack showed dramatic increases in the mass and volumetric power densities by ∼4 times and ∼5 times, respectively, compared with those of a commercial diesel generator with similar power level. As a result, this paper assures the feasibility of the light-weight micro-power pack using a MGT and automotive alternators for EVs.

  13. The structure of tropical forests and sphere packings.

    Science.gov (United States)

    Taubert, Franziska; Jahn, Markus Wilhelm; Dobner, Hans-Jürgen; Wiegand, Thorsten; Huth, Andreas

    2015-12-08

    The search for simple principles underlying the complex architecture of ecological communities such as forests still challenges ecological theorists. We use tree diameter distributions--fundamental for deriving other forest attributes--to describe the structure of tropical forests. Here we argue that tree diameter distributions of natural tropical forests can be explained by stochastic packing of tree crowns representing a forest crown packing system: a method usually used in physics or chemistry. We demonstrate that tree diameter distributions emerge accurately from a surprisingly simple set of principles that include site-specific tree allometries, random placement of trees, competition for space, and mortality. The simple static model also successfully predicted the canopy structure, revealing that most trees in our two studied forests grow up to 30-50 m in height and that the highest packing density of about 60% is reached between the 25- and 40-m height layer. Our approach is an important step toward identifying a minimal set of processes responsible for generating the spatial structure of tropical forests.

  14. Chondrogenesis of human bone marrow mesenchymal stem cells in 3-dimensional, photocrosslinked hydrogel constructs: Effect of cell seeding density and material stiffness.

    Science.gov (United States)

    Sun, Aaron X; Lin, Hang; Fritch, Madalyn R; Shen, He; Alexander, Pete G; DeHart, Michael; Tuan, Rocky S

    2017-08-01

    Three-dimensional hydrogel constructs incorporated with live stem cells that support chondrogenic differentiation and maintenance offer a promising regenerative route towards addressing the limited self-repair capabilities of articular cartilage. In particular, hydrogel scaffolds that augment chondrogenesis and recapitulate the native physical properties of cartilage, such as compressive strength, can potentially be applied in point-of-care procedures. We report here the synthesis of two new materials, [poly-l-lactic acid/polyethylene glycol/poly-l-lactic acid] (PLLA-PEG 1000) and [poly-d,l-lactic acid/polyethylene glycol/poly-d,l-lactic acid] (PDLLA-PEG 1000), that are biodegradable, biocompatible (>80% viability post fabrication), and possess high, physiologically relevant mechanical strength (∼1500 to 1800kPa). This study examined the effects of physiologically relevant cell densities (4, 8, 20, and 50×10 6 /mL) and hydrogel stiffnesses (∼150kPa to∼1500kPa Young's moduli) on chondrogenesis of human bone marrow stem cells incorporated in hydrogel constructs fabricated with these materials and a previously characterized PDLLA-PEG 4000. Results showed that 20×10 6 cells/mL, under a static culture condition, was the most efficient cell seeding density for extracellular matrix (ECM) production on the basis of hydroxyproline and glycosaminoglycan content. Interestingly, material stiffness did not significantly affect chondrogenesis, but rather material concentration was correlated to chondrogenesis with increasing levels at lower concentrations based on ECM production, chondrogenic gene expression, and histological analysis. These findings establish optimal cell densities for chondrogenesis within three-dimensional cell-incorporated hydrogels, inform hydrogel material development for cartilage tissue engineering, and demonstrate the efficacy and potential utility of PDLLA-PEG 1000 for point-of-care treatment of cartilage defects. Engineering cartilage with

  15. Light propagation in close-packed disperse media

    Science.gov (United States)

    Ivanov, Arkadii P.; Loiko, Valerii A.; Dik, Vladimir P.

    The book is concerned with the problem of radiation transfer in disperse media with a high concentration of scattering centers. In particular, attention is given to the effect of correlation in the location of discrete inhomogeneities and their reradiation on the angular, spatial, and temporal characteristics of the radiation emitted from the medium. An analysis is made of the effect of packing density on the quality of optical image transmission. It is shown that the light scattering and absorption characteristics can be sometimes estimated by using the equation of radiation transfer rather than equations of multiple wave scattering.

  16. Origin of Noncubic Scaling Law in Disordered Granular Packing

    Energy Technology Data Exchange (ETDEWEB)

    Xia, Chengjie; Li, Jindong; Kou, Binquan; Cao, Yixin; Li, Zhifeng; Xiao, Xianghui; Fu, Yanan; Xiao, Tiqiao; Hong, Liang; Zhang, Jie; Kob, Walter; Wang, Yujie

    2017-06-01

    Recent diffraction experiments on metallic glasses have unveiled an unexpected non-cubic scaling law between density and average interatomic distance, which lead to the speculations on the presence of fractal glass order. Using X-ray tomography we identify here a similar non-cubic scaling law in disordered granular packing of spherical particles. We find that the scaling law is directly related to the contact neighbors within first nearest neighbor shell, and therefore is closely connected to the phenomenon of jamming. The seemingly universal scaling exponent around 2.5 arises due to the isostatic condition with contact number around 6, and we argue that the exponent should not be universal.

  17. Natural dye extracted from karkadah and its application in dye-sensitized solar cells: experimental and density functional theory study.

    Science.gov (United States)

    Reda, S M; Soliman, K A

    2016-02-01

    This work presents an experimental and theoretical study of cyanidin natural dye as a sensitizer for ZnO dye-sensitized solar cells. ZnO nanoparticles were prepared using ammonia and oxalic acid as a capping agent. The calculated average size of the synthesized ZnO with different capping agents was found to be 32.1 nm. Electronic properties of cyanidin and delphinidin dye were studied using density functional theory (DFT) and time-dependent DFT with a B3LYP/6-31G(d,p) level. By comparing the theoretical results with the experimental data, the cyanidin dye can be used as a sensitizer in dye-sensitized solar cells. An efficiency of 0.006% under an AM-1.5 illumination at 100  mW/cm(2) was attained. The influence of dye adsorption time on the solar cell performance is discussed.

  18. Circulating Zonulin Correlates with Density of Enteroviruses and Tolerogenic Dendritic Cells in the Small Bowel Mucosa of Celiac Disease Patients.

    Science.gov (United States)

    Vorobjova, Tamara; Raikkerus, Helerin; Kadaja, Lumme; Talja, Ija; Uibo, Oivi; Heilman, Kaire; Uibo, Raivo

    2017-02-01

    Impaired intestinal integrity, including increased permeability of the small bowel mucosa, has been shown in patients with celiac disease (CD) as well as with type 1 diabetes (T1D). Zonulin (ZO, pre-haptoglobin), a tight junction regulator, plays a particular role in the regulation of intestinal barrier function and in the pathogenesis of the above-mentioned diseases. To investigate whether enteroviruses (EVs) and immunoregulatory cells are associated with intestinal permeability in patients with CD alone and with coexistent T1D. Altogether 80 patients (mean age 10.68 ± 6.69 years) who had undergone small bowel biopsy were studied. Forty patients with functional dyspepsia and normal small bowel mucosa formed the control group. The circulating ZO level in sera was evaluated using ELISA. The densities of EV, FOXP3+ regulatory T cells (Tregs), indoleamine 2,3-dioxygenase (IDO+) dendritic cells (DCs) and glutamic acid dexarboxylase (GAD)65+ cells in small bowel mucosa were investigated by immunohistochemistry. The expression analysis of FOXP3, tight junction protein 1 (TJP1), gap junction (GJA1), IDO and CD103 genes was evaluated by real-time PCR. The ZO level was higher in CD patients compared to subjects with a normal small bowel mucosa, particularly in those with Marsh IIIc atrophy (p = 0.01), and correlated with the density of EV (r = 0.63; p = 0.0003) and IDO+ DCs (r = 0.58; p = 0.01) in the small bowel mucosa. The density of GAD65+ epithelial cells was correlated with the density of EV (r = 0.59; p = 0.03) and IDO+ DCs (r = 0.78; p = 0.004) in CD patients. The relative expression of FOXP3 mRNA in the small bowel mucosa tissue was significantly higher in patients with CD, compared to subjects with a normal mucosa, and correlated with the density of EV (r = 0.62; p = 0.017) as well as with the relative expression of IDO mRNA (r = 0.54; p = 0.019). The CD is associated with elevation of the circulating ZO level, the value of which

  19. Hashish Body Packing: A Case Report

    Directory of Open Access Journals (Sweden)

    Manuel Jesus Soriano-Perez

    2009-01-01

    Full Text Available A 42-year-old African male was brought by the police to the emergency department under suspicion of drug smuggling by body-packing. Plain abdominal radiograph showed multiple foreign bodies within the gastrointestinal tract. Contrast-enhanced abdominal CT confirmed the findings, and the patient admitted to have swallowed “balls” of hashish. Body-packing is a recognized method of smuggling drugs across international borders. Body packers may present to the emergency department because of drug toxicity, intestinal obstruction, or more commonly, requested by law-enforcement officers for medical confirmation or exclusion of suspected body packing.

  20. "allometry" Deterministic Approaches in Cell Size, Cell Number and Crude Fiber Content Related to the Physical Quality of Kangkong (Ipomoea reptans) Grown Under Different Plant Density Pressures

    Science.gov (United States)

    Selamat, A.; Atiman, S. A.; Puteh, A.; Abdullah, N. A. P.; Mohamed, M. T. M.; Zulkeefli, A. A.; Othman, S.

    Kangkong, especially the upland type (Ipomoea reptans) is popularly consumed as a vegetable dish in the South East Asian countries for its quality related to Vitamins (A and C) and crude fiber contents. Higher fiber contents would prevent from the occurrence of colon cancer and diverticular disease. With young stem edible portion, its cell number and size contribute to the stem crude fiber content. The mathematical approach of allometry of cell size, number, and fiber content of stem could be used in determining the 'best' plant density pressure in producing the quality young stem to be consumed. Basically, allometry is the ratio of relative increment (growth or change) rates of two parameters, or the change rate associated to the log of measured variables relationship. Kangkog grown equal or lower than 55 plants m-2 produced bigger individual plant and good quality (physical) kangkong leafy vegetable, but with lower total yield per unit area as compared to those grown at higher densities.

  1. New stopping cell capabilities : RF carpet performance at high gas density and cryogenic operation

    NARCIS (Netherlands)

    Ranjan, M.; Purushothaman, S.; Dickel, T.; Geissel, H.; Plass, W. R.; Schaefer, D.; Scheidenberger, C.; Van de Walle, J.; Weick, H.; Dendooven, P.

    2011-01-01

    We have developed a stopping cell to be used at the FRS and Super-FRS (Superconducting FRagment Separator) at the GSI Helmholtz Centre for Heavy-Ion Research and the Facility for Antiproton and Ion Research (FAIR), both in Darmstadt, Germany. The cell has a stopping volume with a length of 1m and a

  2. Comparing the efficacy of mature mud pack and hot pack treatments for knee osteoarthritis.

    Science.gov (United States)

    Sarsan, Ayşe; Akkaya, Nuray; Ozgen, Merih; Yildiz, Necmettin; Atalay, Nilgun Simsir; Ardic, Fusun

    2012-01-01

    The objective of this study is to compare the efficacy of mature mud pack and hot pack therapies on patients with knee osteoarthritis. This study was designed as a prospective, randomized-controlled, and single-blinded clinical trial. Twenty-seven patients with clinical and radiologic evidence of knee osteoarthritis were randomly assigned into two groups and were treated with mature mud packs (n 15) or hot packs (n=12). Patients were evaluated for pain [based on the visual analog scale (VAS)], function (WOMAC, 6 min walking distance), quality of life [Short Form-36 (SF-36)], and serum levels of tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), and insulin-like growth factor-1 (IGF-1) at baseline, post-treatment, and 3 and 6~months after treatment. The mud pack group shows a significant improvement in VAS, pain, stifness, and physical function domains of WOMAC. The difference between groups of pain and physical activity domains is significant at post-treatment in favor of mud pack. For a 6 min walking distance, mud pack shows significant improvement, and the difference is significant between groups in favor of mud pack at post-treatment and 3 and 6 months after treatment. Mud pack shows significant improvement in the pain subscale of SF-36 at the third month continuing until the sixth month after the treatment. Significant improvements are found for the social function, vitality/energy, physical role disability, and general health subscales of SF-36 in favor of the mud pack compared with the hot pack group at post-treatment. A significant increase is detected for IGF-1 in the mud pack group 3 months after treatment compared with the baseline, and the difference is significant between groups 3 months after the treatment. Mud pack is a favorable option compared with hotpack for pain relief and for the improvement of functional conditions in treating patients with knee osteoarthritis.

  3. Tanshindiol C inhibits oxidized low-density lipoprotein induced macrophage foam cell formation via a peroxiredoxin 1 dependent pathway.

    Science.gov (United States)

    Yang, Yuyu; Li, Xueyan; Peng, Liying; An, Lin; Sun, Ningyuan; Hu, Xuewen; Zhou, Ping; Xu, Yong; Li, Ping; Chen, Jun

    2018-03-01

    NF-E2-related factor 2 (Nrf2) has been shown to be protective in atherosclerosis. The loss of Nrf2 in macrophages enhances foam cell formation and promotes early atherogenesis. Tanshindiol C (Tan C) is isolated from the root of Salvia miltiorrhiza Bge., a traditional Chinese medicine that has been used for the treatment of several cardiovascular diseases for many years. This study was aimed to test the potential role of Tan C against macrophage foam cell formation and to explore the underlying mechanism. Firstly, we observed that Tan C markedly suppressed oxidized low-density lipoprotein (oxLDL) induced macrophage foam cell formation. Then, we found that Tan C was an activator of both Nrf2 and Sirtuin 1 (Sirt1) in macrophages. Nrf2 and Sirt1 synergistically activated the transcription of anti-oxidant peroxiredoxin 1 (Prdx1) after Tan C treatment. More important, we demonstrated that silencing of Prdx1 promoted oxLDL-induced macrophage foam cell formation. Prdx1 upregulated adenosine triphosphate-binding cassette (ABC) transporter A1 (ABCA1) expression and decreased intracellular lipid accumulation. Furthermore, Tan C ameliorated oxLDL induced macrophage foam cell formation in a Prdx1-dependent manner. These observations suggest that Tan C protects macrophages from oxLDL induced foam cell formation via activation of Prdx1/ABCA1 signaling and that Prdx1 may be a novel target for therapeutic intervention of atherosclerosis. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. Particle packing of cement and silica fume in pastes using an analytical model

    Directory of Open Access Journals (Sweden)

    A. HERMANN

    Full Text Available When added to concrete in appropriate content, silica fume may provide an increase in the mechanical strength of the material due to its high pozzolanic reactivity. In addition to the chemical contribution, physical changes can also be observed in concretes with silica fume due to an improvement in the particle packing of the paste. This is a result of their small size spherical particles, which fill the voids between the larger cement grains. However, it is necessary to properly establish the cement replacement content by silica fume, because at high amounts, which exceed the volume of voids between the cement particles, silica fume can promote the loosening of these particles. Thus, instead of filling the voids and increasing the packing density, the addition of silica fume will increase the volume of voids, decreasing the solid concentration. Consequently, this will impair the properties of the concrete. The objective of this paper is to use a particle packing analytical model, the CPM (Compressible Packing Model, to verify the maximum packing density of cement and silica fume, which could be associated with the silica fume optimum content in pastes. The ideal content of silica fume in pastes, mortars and concretes is usually experimentally determined. However, a theoretical study to contrast experimental data may help understanding the behaviour of silica fume in mixes. Theoretical results show maximum amounts of silica fume in the order of 18 to 20% of the cement weight, which is high considering recommendations on literature of 15%. Nevertheless, the packing model does not consider the effect of silica fume high specific surface on the agglomeration of particles or water demand. Hence, the packing density predicted by this model cannot be used as the single parameter in determining the optimum amount of silica fume in pastes.

  5. Acceptor and Excitation Density Dependence of the Ultrafast Polaron Absorption Signal in Donor-Acceptor Organic Solar Cell Blends.

    Science.gov (United States)

    Zarrabi, Nasim; Burn, Paul L; Meredith, Paul; Shaw, Paul E

    2016-07-21

    Transient absorption spectroscopy on organic semiconductor blends for solar cells typically shows efficient charge generation within ∼100 fs, accounting for the majority of the charge carriers. In this Letter, we show using transient absorption spectroscopy on blends containing a broad range of acceptor content (0.01-50% by weight) that the rise of the polaron signal is dependent on the acceptor concentration. For low acceptor content (10%) most polarons are generated within 200 fs. The rise time in blends with low acceptor content was also found to be sensitive to the pump fluence, decreasing with increasing excitation density. These results indicate that the sub-100 fs rise of the polaron signal is a natural consequence of both the high acceptor concentrations in many donor-acceptor blends and the high excitation densities needed for transient absorption spectroscopy, which results in a short average distance between the exciton and the donor-acceptor interface.

  6. The relation between FoxP3⁺ regulatory T cells and fungal density in oral paracoccidioidomycosis: a preliminary study.

    Science.gov (United States)

    Cardoso, Rhanderson Miller Nascimento; Jham, Bruno Correia; do Carmo, Gabriela Mota; Batista, Aline Carvalho; de Oliveira, Flávia Aparecida; de Paula, Elbio Candido; Mesquita, Ricardo Alves; da Silva, Tarcília Aparecida; Duarte, Eliza Carla Barroso

    2014-12-01

    Regulatory T (Treg) cells may play an important role in the pathogenesis of paracoccidioidomycosis (PCM), but data on the role of Treg cells in the context of oral PCM are still scarce. The objectives of this study were to investigate the density of FoxP3(+) T regulatory cells in oral PCM and to correlate the results with the density of Paracoccidioides brasiliensis in the lesions. Cases of chronic oral PCM seen between 2000 and 2008 were included in this study. The diagnosis of all lesions was confirmed with histopathological examination and Grocott-Gomori staining. The quantitative analysis of the viable fungi was conducted in all cases with Grocott-stained slides. Treg cells were identified using antibodies against FoxP3. Pearson correlation coefficient was used to test the correlation between the density of fungi and Treg cells. Results were considered significant when P < 0.05. A total of 11 cases of oral PCM were obtained. There was a positive correlation between fungal density and FoxP3(+) Treg cells density in oral lesions, however, without statistical significance. A positive relation between Treg cells and fungal density was seen in oral PCM. Further studies are required to further elucidate the role of these cells in the pathogenesis of oral PCM, as well the clinical significance of these findings. © 2014 Blackwell Verlag GmbH.

  7. High performance of mixed halide perovskite solar cells: Role of halogen atom and plasmonic nanoparticles on the ideal current density of cell

    Science.gov (United States)

    Mohebpour, Mohammad Ali; Saffari, Mohaddeseh; Soleimani, Hamid Rahimpour; Tagani, Meysam Bagheri

    2018-03-01

    To be able to increase the efficiency of perovskite solar cells which is one of the most substantial challenges ahead in photovoltaic industry, the structural and optical properties of perovskite CH3NH3PbI3-xBrx for values x = 1-3 have been studied employing density functional theory (DFT). Using the optical constants extracted from DFT calculations, the amount of light reflectance and ideal current density of a simulated single-junction perovskite solar cell have been investigated. The results of DFT calculations indicate that adding halogen bromide to CH3NH3PbI3 compound causes the relocation of energy bands in band structure which its consequence is increasing the bandgap. In addition, the effect of increasing Br in this structure can be seen as a reduction in lattice constant, refractive index, extinction and absorption coefficient. As well, results of the simulation suggest a significant current density enhancement as much as 22% can be achieved by an optimized array of Platinum nanoparticles that is remarkable. This plan is able to be a prelude for accomplishment of solar cells with higher energy conversion efficiency.

  8. A cell spot microarray method for production of high density siRNA transfection microarrays

    Directory of Open Access Journals (Sweden)

    Mpindi John-Patrick

    2011-03-01

    Full Text Available Abstract Background High-throughput RNAi screening is widely applied in biological research, but remains expensive, infrastructure-intensive and conversion of many assays to HTS applications in microplate format is not feasible. Results Here, we describe the optimization of a miniaturized cell spot microarray (CSMA method, which facilitates utilization of the transfection microarray technique for disparate RNAi analyses. To promote rapid adaptation of the method, the concept has been tested with a panel of 92 adherent cell types, including primary human cells. We demonstrate the method in the systematic screening of 492 GPCR coding genes for impact on growth and survival of cultured human prostate cancer cells. Conclusions The CSMA method facilitates reproducible preparation of highly parallel cell microarrays for large-scale gene knockdown analyses. This will be critical towards expanding the cell based functional genetic screens to include more RNAi constructs, allow combinatorial RNAi analyses, multi-parametric phenotypic readouts or comparative analysis of many different cell types.

  9. In situ cannulation, microgrid follow-up and low-density plating provide first passage endothelial cell masscultures for in vitro lining.

    Science.gov (United States)

    Zilla, P; Fasol, R; Dudeck, U; Siedler, S; Preiss, P; Fischlein, T; Müller-Glauser, W; Baitella, G; Sanan, D; Odell, J

    1990-08-01

    A rapid and reliable harvest and culture technique was developed to provide a sufficient number of autologous endothelial cells for the confluent in vitro lining of cardiovascular prostheses. Enzymatic endothelial cell detachment was achieved by the in situ application of collagenase to short vessel segments. This harvest technique resulted in a complete lack of contaminating smooth muscle cells in all of 124 cultures from nonhuman primates and 13 cultures from human adults. The use of a microgrid technique enabled the daily in situ quantification of available endothelial cells. To assess ideal plating densities after passage the population doubling time was continuously related to the cell density. Surprisingly, a low plating density of 1.5 X 10(3) endothelial cells/cm2 achieved 43% shorter cell cycles than the usual plating density of 1.0 X 10(4) endothelial cells/cm2. Moreover, low density plating enabled mass cultures after one single cell passage, thereby reducing the cell damaging effect of trypsin. When the growth characteristics of endothelial cells from five anatomically different vessel sites were compared, the external jugular vein--which would be easily accessible and dispensable in each patient--proved to be an excellent source for endothelial cell cultures. By applying in situ administration of collagenase, low density plating and microgrid follow-up to adult human saphenous vein endothelial cells, 14,000,000 first passage endothelial cells--sufficient for the in vitro lining of long vascular prostheses--were obtained 26.2 days after harvest. (95% confidence interval:22.3 to 32.2 days).

  10. High-Density Dielectrophoretic Microwell Array for Detection, Capture, and Single-Cell Analysis of Rare Tumor Cells in Peripheral Blood.

    Directory of Open Access Journals (Sweden)

    Atsushi Morimoto

    Full Text Available Development of a reliable platform and workflow to detect and capture a small number of mutation-bearing circulating tumor cells (CTCs from a blood sample is necessary for the development of noninvasive cancer diagnosis. In this preclinical study, we aimed to develop a capture system for molecular characterization of single CTCs based on high-density dielectrophoretic microwell array technology. Spike-in experiments using lung cancer cell lines were conducted. The microwell array was used to capture spiked cancer cells, and captured single cells were subjected to whole genome amplification followed by sequencing. A high detection rate (70.2%-90.0% and excellent linear performance (R2 = 0.8189-0.9999 were noted between the observed and expected numbers of tumor cells. The detection rate was markedly higher than that obtained using the CellSearch system in a blinded manner, suggesting the superior sensitivity of our system in detecting EpCAM- tumor cells. Isolation of single captured tumor cells, followed by detection of EGFR mutations, was achieved using Sanger sequencing. Using a microwell array, we established an efficient and convenient platform for the capture and characterization of single CTCs. The results of a proof-of-principle preclinical study indicated that this platform has potential for the molecular characterization of captured CTCs from patients.

  11. Use of Limiting Dilution Method for Isolation of Nucleus Pulposus Mesenchymal Stem/Progenitor Cells and Effects of Plating Density on Biological Characteristics and Plasticity

    Directory of Open Access Journals (Sweden)

    Linghan Lin

    2017-01-01

    Full Text Available Objectives. To evaluate the effects of the limiting dilution method and plating density in rat nucleus pulposus mesenchymal stem/progenitor cells (NPMSCs. Materials and Methods. Nucleus pulposus tissues were isolated from 12-week-old male Sprague-Dawley rats and NPMSCs were isolated using limiting dilution method. Cells were then classified into 3 groups according to plating density. Cell morphologies were observed, and colony-forming units, migration abilities, proliferative capacities, cell cycle percentages, multilineage differentiation capacities, stem cell biomarker expression levels, and immunophenotyping were also examined in each group. Results. Low density group (LD had higher morphological homogeneity, stronger colony-forming ability, higher cell proliferation capacity, and enhanced cell migration ability relative to the other two groups (p<0.05. Moreover, LD had more cells entering S phase, with fewer cells arrested in G0/G1 phase (p<0.05. While all three density groups showed a multilineage differentiation potential, LD showed a higher degree of observed and semiquantified lineage specific staining (p<0.05. Furthermore, LD displayed higher expression levels of stem cell biomarkers (Nanog, Oct4, and Sox2 and showed higher percentages of CD29+, CD44+, and CD90+ cells (p<0.05 following flow cytometry analysis. Conclusions. Limiting dilution method is suggested when isolating NPMSCs as a means of improving cell activity and plasticity.

  12. Levels of high-density lipoprotein cholesterol (HDL-C among children with steady-state sickle cell disease

    Directory of Open Access Journals (Sweden)

    Seixas Magda O

    2010-08-01

    Full Text Available Abstract Background The search for sickle