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Sample records for unit cell structure

  1. Biology 23. Unit One -- The Cell: Structure and Physiology.

    Science.gov (United States)

    Nederland Independent School District, TX.

    GRADES OR AGES: Not given. SUBJECT MATTER: Biology, the structure and physiology of the cell. ORGANIZATION AND PHYSICAL APPEARANCE: There are four sections: a) objectives for the unit, b) bibliography, c) activities, and d) evaluation. The guide is directed to the student rather than the teacher. The guide is mimeographed and stapled, with no…

  2. Unit cell geometry of multiaxial preforms for structural composites

    Science.gov (United States)

    Ko, Frank; Lei, Charles; Rahman, Anisur; Du, G. W.; Cai, Yun-Jia

    1993-01-01

    The objective of this study is to investigate the yarn geometry of multiaxial preforms. The importance of multiaxial preforms for structural composites is well recognized by the industry but, to exploit their full potential, engineering design rules must be established. This study is a step in that direction. In this work the preform geometry for knitted and braided preforms was studied by making a range of well designed samples and studying them by photo microscopy. The structural geometry of the preforms is related to the processing parameters. Based on solid modeling and B-spline methodology a software package is developed. This computer code enables real time structural representations of complex fiber architecture based on the rule of preform manufacturing. The code has the capability of zooming and section plotting. These capabilities provide a powerful means to study the effect of processing variables on the preform geometry. the code also can be extended to an auto mesh generator for downstream structural analysis using finite element method. This report is organized into six sections. In the first section the scope and background of this work is elaborated. In section two the unit cell geometries of braided and multi-axial warp knitted preforms is discussed. The theoretical frame work of yarn path modeling and solid modeling is presented in section three. The thin section microscopy carried out to observe the structural geometry of the preforms is the subject in section four. The structural geometry is related to the processing parameters in section five. Section six documents the implementation of the modeling techniques into the computer code MP-CAD. A user manual for the software is also presented here. The source codes and published papers are listed in the Appendices.

  3. High light-extraction-efficiency OLED based on photonic crystal slab structures with taper unit cells

    Institute of Scientific and Technical Information of China (English)

    YAN Rong-jin; WANG Qing-kang

    2006-01-01

    To improve the light-extraction-efficiency of OLED,we introduced PCS (Photonic Crystal Slab) structures into the interface of ITO layer and glass substrate.PCS structures with Taper unit cells are proved to be effective in reducing the energy of guided wave trapped in high refractive index material,and an increase of light-extraction-efficiency to 95.26% is gained.This enhancement is much greater than the traditional PCS with cylinder unit cells (60%-70%).Physical mechanisms of light-extraction-efficiency enhancement in these structures are further discussed.

  4. Teaching Basic Science Environmentally, The Concept: The cell is basic unit of structure of most organisms.

    Science.gov (United States)

    Busch, Phyllis S.

    1985-01-01

    Suggests simple ways to introduce students to the concept that the cell is the basic unit of structure of most organisms. Mentions materials for microscope study that are readily available and easy to handle, e.g., membranes from between the scales of the onion bulb, thin-leaved plants, pond water, and pollen. (JHZ)

  5. Experimental broadband absorption enhancement in silicon nanohole structures with optimized complex unit cells.

    Science.gov (United States)

    Lin, Chenxi; Martínez, Luis Javier; Povinelli, Michelle L

    2013-09-09

    We design silicon membranes with nanohole structures with optimized complex unit cells that maximize broadband absorption. We fabricate the optimized design and measure the optical absorption. We demonstrate an experimental broadband absorption about 3.5 times higher than an equally-thick thin film.

  6. Water proton configurations in structures I, II, and H clathrate hydrate unit cells.

    Science.gov (United States)

    Takeuchi, Fumihito; Hiratsuka, Masaki; Ohmura, Ryo; Alavi, Saman; Sum, Amadeu K; Yasuoka, Kenji

    2013-03-28

    Position and orientation of water protons need to be specified when the molecular simulation studies are performed for clathrate hydrates. Positions of oxygen atoms in water are experimentally determined by X-ray diffraction analysis of clathrate hydrate structures, but positions of water hydrogen atoms in the lattice are disordered. This study reports a determination of the water proton coordinates in unit cell of structure I (sI), II (sII), and H (sH) clathrate hydrates that satisfy the ice rules, have the lowest potential energy configuration for the protons, and give a net zero dipole moment. Possible proton coordinates in the unit cell were chosen by analyzing the symmetry of protons on the hexagonal or pentagonal faces in the hydrate cages and generating all possible proton distributions which satisfy the ice rules. We found that in the sI and sII unit cells, proton distributions with small net dipole moments have fairly narrow potential energy spreads of about 1 kJ∕mol. The total Coulomb potential on a test unit charge placed in the cage center for the minimum energy∕minimum dipole unit cell configurations was calculated. In the sI small cages, the Coulomb potential energy spread in each class of cage is less than 0.1 kJ∕mol, while the potential energy spread increases to values up to 6 kJ∕mol in sH and 15 kJ∕mol in the sII cages. The guest environments inside the cages can therefore be substantially different in the sII case. Cartesian coordinates for oxygen and hydrogen atoms in the sI, sII, and sH unit cells are reported for reference.

  7. Unit Cell Structure of Crystal Polytypes in InAs and InSb Nanowires

    DEFF Research Database (Denmark)

    Kriegner, Dominik; Panse, Christian; Mandl, Bernhard

    2011-01-01

    , wurtzite, and 4H polytypes for InAs and InSb nanowires, using X-ray diffraction and transmission electron microscopy. The results are compared to density functional theory calculations. Experiment and theory show that the occurrence of hexagonal bilayers tends to stretch the distances of atomic layers...... parallel to the c axis and to reduce the in-plane distances compared to those in zinc blende. The change of the lattice parameters scales linearly with the hexagonality of the polytype, defined as the fraction of bilayers with hexagonal character within one unit cell....

  8. 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 .

  9. Sickle Cell Unit.

    Science.gov (United States)

    Canipe, Stephen L.

    Included in this high school biology unit on sickle cell anemia are the following materials: a synopsis of the history of the discovery and the genetic qualities of the disease; electrophoresis diagrams comparing normal, homozygous and heterozygous conditions of the disease; and biochemical characteristics and population genetics of the disease. A…

  10. One-step synthesis of mesoporous pentasil zeolite with single-unit-cell lamellar structural features

    Science.gov (United States)

    Tsapstsis, Michael; Zhang, Xueyi

    2015-11-17

    A method for making a pentasil zeolite material includes forming an aqueous solution that includes a structure directing agent and a silica precursor; and heating the solution at a sufficient temperature and for sufficient time to form a pentasil zeolite material from the silica precursor, wherein the structure directing agent includes a quaternary phosphonium ion.

  11. 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…

  12. Selective laser melting: a unit cell approach for the manufacture of porous, titanium, bone in-growth constructs, suitable for orthopedic applications. II. Randomized structures.

    Science.gov (United States)

    Mullen, Lewis; Stamp, Robin C; Fox, Peter; Jones, Eric; Ngo, Chau; Sutcliffe, Christopher J

    2010-01-01

    In this study, the unit cell approach, which has previously been demonstrated as a method of manufacturing porous components suitable for use as orthopedic implants, has been further developed to include randomized structures. These random structures may aid the bone in-growth process because of their similarity in appearance to trabecular bone and are shown to carry legacy properties that can be related back to the original unit cell on which they are ultimately based. In addition to this, it has been shown that randomization improves the mechanical properties of regular unit cell structures, resulting in anticipated improvements to both implant functionality and longevity. The study also evaluates the effect that a post process sinter cycle has on the components, outlines the improved mechanical properties that are attainable, and also the changes in both the macro and microstructure that occur.

  13. First-principles investigation of the effect of charged unit cell on the electronic structure of two-dimensional MoS2

    Science.gov (United States)

    Shekaari, Ashkan; Abolhassani, Mohammad Reza; Lashgari, Hamed

    2017-01-01

    Density-functional theory has been applied to investigate the effect of charged unit cell on the structural and electronic properties of two-dimensional MoS2 within PBE-GGA. The charge of the unit cell of the monolayer changes from zero to n = ± 4 e with e the absolute value of the elementary electric charge. Variations of the lattice constant, Mo-S bond length, S-Mo-S bond angle, total energy, exchange and correlation contributions, and the Fermi level versus n have been calculated quantitatively, indicating decrease in the stability of the atomic structure of the monolayer with increase in the absolute value of n. It is found that the Fermi level for two-dimensional MoS2 is a function of both the number of electrons in allowed states and the inverse of the volume of the unit cell. The electronic properties of each monolayer have been also calculated via examining the related electronic band structure and density of states. Results broadly support the view that the effect of charged unit cell (n =+ e to - 4 e) on the electronic properties of MoS2 monolayer is manifested in the form of semiconductor-to-metal transition in addition to the Fermi level shift. It is also verified that as the negative charge of the unit cell increases from n = - e to - 4 e , there is an ever-increasing trend in the total number of allowed electronic states at the Fermi level, implying a direct correlation between electrical conductivity and the value of n in a way that the more negative the charge of the unit cell, the higher the electrical conductivity of the monolayer.

  14. Synthesis, Crystal Structure, and Magnetic Properties of Giant Unit Cell Intermetallics R117Co52+δSn112+γ (R = Y, La, Pr, Nd, Ho

    Directory of Open Access Journals (Sweden)

    Ping Chai

    2016-12-01

    Full Text Available Ternary intermetallics R117Co52+δSn112+γ (R = Y, La, Pr, Nd, and Ho have been prepared by arc-melting followed by annealing at 800 °C. All the compounds belong to the Tb117Fe52Ge112 structure type (space group Fm 3 ¯ m characterized by a complex giant cubic unit cell with a ~ 30 Å. The single-crystal structure determination of Y- and La-containing compounds reveals a significant structural disorder. A comparison of these and earlier reported crystal structures of R117Co52+δSn112+γ suggests that more extensive disorder occurs for structures that contain larger lanthanide atoms. This observation can be explained by the need to maintain optimal bonding interactions as the size of the unit cell increases. Y117Co56Sn115 exhibits weak paramagnetism due to the Co sublattice and does not show magnetic ordering in the 1.8–300 K range. Ho117Co55Sn108 shows ferromagnetic ordering at 10.6 K. Both Pr117Co54Sn112 and Nd117Co54Sn111 exhibit antiferromagnetic ordering at 17 K and 24.7 K, respectively, followed by a spin reorientation transition at lower temperature.

  15. Tetrahedral Units: For Dodecahedral Super-Structures

    CERN Document Server

    Ortiz, Y; Liebman, J F

    2016-01-01

    Different novel organic-chemical possibilities for tetrahedral building units are considered, with attention to their utility in constructing different super-structures. As a representative construction we consider the use of sets of 20 such identical tetrahedral units to form a super-dodecahedron.

  16. Bifurcation structure of the special class of nonstationary regimes emerging in the 2D inertially coupled, unit-cell model: Analytical study

    Science.gov (United States)

    Vorotnikov, K.; Starosvetsky, Y.

    2016-09-01

    Present work is devoted to the analytical investigation of the bifurcation structure of special class of nonstationary low-energy regimes emerging in the locally resonant unit-cell model. System under consideration comprises an outer mass with internal rotator and subject to the 2D, nonlinear local potential. These regimes are characterized by the slow, purely rotational motion of the rotator synchronized with the periodic energy beats between the axial and the lateral vibrations of the outer element. Thus the angular speed of the rotator and the beating frequency of the outer element satisfy the 1:2 resonance condition. In the present study these regimes are referred to as regimes of synchronous nonlinear beats (RSNB). Using the regular muti-scale analysis in the limit of low energy excitation we derive the slow-flow model. To showcase the evolution of RSNBs we used the special Poincaré map technique applied on the slow-flow model. Results of the Poincaré sections unveiled some interesting local bifurcations undergone by these regimes. Further analysis of the slow-flow model enabled us to describe the RSNBs analytically as well as exposed their entire bifurcation structure. The bifurcation analysis has shown the coexistence of several branches of RSNBs corresponding to the regimes of weak and strong, two-dimensional, recurrent energy channeling. We substantiate the results of the analytical study with numerical simulations of the full model and find them to be in the very good agreement.

  17. Frequency Selective Surfaces with Nanoparticles Unit Cell

    Directory of Open Access Journals (Sweden)

    Nga Hung Poon

    2015-09-01

    Full Text Available The frequency selective surface (FSS is a periodic structure with filtering performance for optical and microwave signals. The general periodic arrays made with patterned metallic elements can act as an aperture or patch on a substrate. In this work, two kinds of materials were used to produce unit cells with various patterns. Gold nanoparticles of 25 nm diameter were used to form periodic monolayer arrays by a confined photocatalytic oxidation-based surface modification method. As the other material, silver gel was used to create multiple layers of silver. Due to the ultra-thin nature of the self-assembled gold nanoparticle monolayer, it is very easy to penetrate the FSS with terahertz radiation. However, the isolated silver islands made from silver gel form thicker multiple layers and contribute to much higher reflectance. This work demonstrated that multiple silver layers are more suitable than gold nanoparticles for use in the fabrication of FSS structures.

  18. Unit: Cells, Inspection Set, National Trial Print.

    Science.gov (United States)

    Australian Science Education Project, Toorak, Victoria.

    This trial version of a unit is the series being produced by the Australian Science Education Project provides instructions for students to prepare a variety of cell types and examine them with microscopes. It also gives some information about the variety and function of cells. The core of the unit, which all students are expected to complete,…

  19. 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.

  20. Reversible (unitized) PEM fuel cell devices

    Energy Technology Data Exchange (ETDEWEB)

    Mitlitsky, F; Myers, B; Smith, W F; Weisberg, Molter, T M

    1999-06-01

    Regenerative fuel cells (RFCs) are enabling for many weight-critical portable applications, since the packaged specific energy (>400 Wh/kg) of properly designed lightweight RFC systems is several-fold higher than that of the lightest weight rechargeable batteries. RFC systems can be rapidly refueled (like primary fuel cells), or can be electrically recharged (like secondary batteries) if a refueling infrastructure is not conveniently available. Higher energy capacity systems with higher performance, reduced weight, and freedom from fueling infrastructure are the features that RFCs promise for portable applications. Reversible proton exchange membrane (PEM) fuel cells, also known as unitized regenerative fuel cells (URFCs), or reversible regenerative fuel cells, are RFC systems which use reversible PEM cells, where each cell is capable of operating both as a fuel cell and as an electrolyzer. URFCs further economize portable device weight, volume, and complexity by combining the functions of fuel cells and electrolyzers in the same hardware, generally without any system performance or efficiency reduction. URFCs are being made in many forms, some of which are already small enough to be portable. Lawrence Livermore National Laboratory (LLNL) has worked with industrial partners to design, develop, and demonstrate high performance and high cycle life URFC systems. LLNL is also working with industrial partners to develop breakthroughs in lightweight pressure vessels that are necessary for URFC systems to achieve the specific energy advantages over rechargeable batteries. Proton Energy Systems, Inc. (Proton) is concurrently developing and commercializing URFC systems (UNIGEN' product line), in addition to PEM electrolyzer systems (HOGEN' product line), and primary PEM fuel cell systems. LLNL is constructing demonstration URFC units in order to persuade potential sponsors, often in their own conference rooms, that advanced applications based on URFC s are

  1. Life Functions and Cells: Level II, Unit 7, Lesson 1; Cell Structure: Lesson 2; Tissues, Organs, Systems: Lesson 3; Growth and Nutrition: Lesson 4; Metabolism: Lesson 5. Advanced General Education Program. A High School Self-Study Program.

    Science.gov (United States)

    Manpower Administration (DOL), Washington, DC. Job Corps.

    This self-study program for high-school level contains lessons on: Life Functions and Cells; Cell Structure; Tissues, Organs, Systems; Growth and Nutrition; and Metabolism. Each of the lessons concludes with a Mastery Test to be completed by the student. (DB)

  2. Mechanical behavior of regular open-cell porous biomaterials made of diamond lattice unit cells.

    Science.gov (United States)

    Ahmadi, S M; Campoli, G; Amin Yavari, S; Sajadi, B; Wauthle, R; Schrooten, J; Weinans, H; Zadpoor, A A

    2014-06-01

    Cellular structures with highly controlled micro-architectures are promising materials for orthopedic applications that require bone-substituting biomaterials or implants. The availability of additive manufacturing techniques has enabled manufacturing of biomaterials made of one or multiple types of unit cells. The diamond lattice unit cell is one of the relatively new types of unit cells that are used in manufacturing of regular porous biomaterials. As opposed to many other types of unit cells, there is currently no analytical solution that could be used for prediction of the mechanical properties of cellular structures made of the diamond lattice unit cells. In this paper, we present new analytical solutions and closed-form relationships for predicting the elastic modulus, Poisson׳s ratio, critical buckling load, and yield (plateau) stress of cellular structures made of the diamond lattice unit cell. The mechanical properties predicted using the analytical solutions are compared with those obtained using finite element models. A number of solid and porous titanium (Ti6Al4V) specimens were manufactured using selective laser melting. A series of experiments were then performed to determine the mechanical properties of the matrix material and cellular structures. The experimentally measured mechanical properties were compared with those obtained using analytical solutions and finite element (FE) models. It has been shown that, for small apparent density values, the mechanical properties obtained using analytical and numerical solutions are in agreement with each other and with experimental observations. The properties estimated using an analytical solution based on the Euler-Bernoulli theory markedly deviated from experimental results for large apparent density values. The mechanical properties estimated using FE models and another analytical solution based on the Timoshenko beam theory better matched the experimental observations. Copyright © 2014 Elsevier Ltd

  3. Developing high-performance small molecule organic solar cells via a large planar structure and an electron-withdrawing central unit.

    Science.gov (United States)

    Zhang, Hongtao; Liu, Yongtao; Sun, Yanna; Li, Miaomiao; Kan, Bin; Ke, Xin; Zhang, Qian; Wan, Xiangjian; Chen, Yongsheng

    2016-12-22

    We designed and synthesized a new small molecule donor material named DR3TBDD using an electron-withdrawing unit BDD as the central building block. A PCE of 9.53% with a high Voc of around 1 V was achieved.

  4. Accessing Structure of Megacontrol Type RTU Units

    Directory of Open Access Journals (Sweden)

    A.Pavel

    2008-05-01

    Full Text Available The cases presented in this paper are the results of a practical situation that compare the situation in which the RS485 network could be created, to the situation in which communication with RTU (remote terminal units has to use more than one point to point RS232 connection.

  5. Large, larger, largest--a family of cluster-based tantalum copper aluminides with giant unit cells. I. Structure solution and refinement.

    Science.gov (United States)

    Weber, Thomas; Dshemuchadse, Julia; Kobas, Miroslav; Conrad, Matthias; Harbrecht, Bernd; Steurer, Walter

    2009-06-01

    This is the first of two parts, where we report the structure determination of a novel family of cluster-based intermetallic phases of unprecedented complexity: cF444-Al(63.6)Ta(36.4) (AT-19), a = 19.1663 (1) A, V = 7040 A3, cF(5928-x)-Al(56.6)Cu(3.9)Ta(39.5), x = 20 (ACT-45), a = 45.376 (1) A, V = 93,428 A(3) and cF(23,256-x)-Al(55.4)Cu(5.4)Ta(39.1), x = 122 (ACT-71), a = 71.490 (4) A, V = 365,372 A3. The space group is F43m in all three cases. These cluster-based structures are closely related to the class of Frank-Kasper phases. It is remarkable that all three structures show the same average structure that resembles the cubic Laves phase.

  6. Lithium-Ion Cell Charge-Control Unit Developed

    Science.gov (United States)

    Reid, Concha M.; Manzo, Michelle A.; Buton, Robert M.; Gemeiner, Russel

    2005-01-01

    A lithium-ion (Li-ion) cell charge-control unit was developed as part of a Li-ion cell verification program. This unit manages the complex charging scheme that is required when Li-ion cells are charged in series. It enables researchers to test cells together as a pack, while allowing each cell to charge individually. This allows the inherent cell-to-cell variations to be addressed on a series string of cells and reduces test costs substantially in comparison to individual cell testing.

  7. Novel negative mass density resonant metamaterial unit cell

    Energy Technology Data Exchange (ETDEWEB)

    Cselyuszka, Norbert, E-mail: cselyu@yahoo.com; Sečujski, Milan, E-mail: secujski@uns.ac.rs; Crnojević-Bengin, Vesna, E-mail: bengin@uns.ac.rs

    2015-01-02

    In this paper a novel resonant unit cell of one-dimensional acoustic metamaterials is presented, which exhibits negative effective mass density. We theoretically analyze the unit cell and develop a closed analytical formula for its effective mass density. Then we proceed to demonstrate left-handed propagation of acoustic waves using the proposed unit cell. Finally, we present its dual-band version, capable of operating at two independent frequencies. - Highlights: • A novel acoustic metamaterial unit cell provides Lorentz-type resonant effective mass density. • Analytical formula for effective mass density is derived. • Acoustic bandstop medium and left-handed metamaterial based on the novel unit cell are presented. • Modified version of the unit cell, operating at two independent frequencies, is proposed.

  8. Porous silicon for micro-sized fuel cell reformer units

    Energy Technology Data Exchange (ETDEWEB)

    Presting, H.; Konle, J.; Starkov, V.; Vyatkin, A.; Koenig, U

    2004-04-25

    Randomly, self-organized and ordered anodically etched porous silicon with pore sizes down to hundred nanometers have been fabricated for a variety of automotive applications which range from carrier structures in fuel cell technology up to shower heads for fuel injection in combustion engines. The porous wafers are produced by deep anodic etching which is a very effective and cheap fabrication method compatible to standard Si CMOS fabrication technology. The density of nano- (and micro-) pores can be varied in a wide range by choice of substrate doping level and appropriate electrolyte solution. Surface enlargement up to a factor of 1000 can be achieved [J. Electrochem. Soc. 149 (1) (2002) G70]. After deposition of a catalyst on the inner surface of the pores these structures can be used as an effective catalytic reaction area for the injected hydrocarbons in a micro-steam reformer unit with a small reaction volume. In addition deep anodic etching (DAE) of a pinhole array with very high aspect ratios is demonstrated using a pre-patterned inverted pyramidal array which is produced by lithography and subsequent wet chemical potassium hydroxide (KOH) etch. The structures can also be used as carrier structures for the hydrogen separation membrane of the reforming gas in a reformer unit when a thin layer of palladium is evaporated prior to the anodic etching of the pores. The noble metal foil serves as anode contact during the etch as well as hydrogen separating membrane of the device.

  9. Structural racism and myocardial infarction in the United States

    OpenAIRE

    Lukachko, Alicia; Mark L Hatzenbuehler; Katherine M Keyes

    2014-01-01

    There is a growing research literature suggesting that racism is an important risk factor undermining the health of Blacks in the United States. Racism can take many forms, ranging from interpersonal interactions to institutional/structural conditions and practices. Existing research, however, tends to focus on individual forms of racial discrimination using self-report measures. Far less attention has been paid to whether structural racism may disadvantage the health of Blacks in the United ...

  10. Structural stability estimation of whirling unit

    Institute of Scientific and Technical Information of China (English)

    Son-Jae HWAN; Han-Chang WOO; Lee-Sang RYONG; Lee-Young MOON

    2009-01-01

    Whirling is a cutting process in which a series of cutting edges on whirling ring remove material by turning over a rotating workpiece. In this study static and dynamic stability of whirling unit was estimated by using ADAMS and NASTRAN softwares. Each maximum force acting on the bearing attached to the spindle assembly and the cutting tool attached to the whirling ring with the rotating speed of 6 000 r/min was 235 N and 902 N respectively. The maximum stress of 0.74 Mpa on the base frame is far smaller than the yield strength of 282 Mpa. The calculated natural frequency of 148 Hz of the system is far from the frequency of the driving speed of 6 000 r/min. The experimentally obtained maximum cutting force of 792 N is smaller than that of calculated value. And the experimentally obtained natural frequency of 118 Hz is beyond the driving speed of 6 000 r/min. From above results it can be judged that the whirling system is statically and dynamically stable.

  11. Cell Structure Study.

    Science.gov (United States)

    Ekstrom, James V.

    2000-01-01

    Presents an activity in which students use microscopes and digital images to examine Elodea, a fresh water plant, before and after the process of plasmolysis, identify plant cellular structures before and after plasmolysis, and calculate the size of the plant's vacuole. (ASK)

  12. A Unit Cell Laboratory Experiment: Marbles, Magnets, and Stacking Arrangements

    Science.gov (United States)

    Collins, David C.

    2011-01-01

    An undergraduate first-semester general chemistry laboratory experiment introducing face-centered, body-centered, and simple cubic unit cells is presented. Emphasis is placed on the stacking arrangement of solid spheres used to produce a particular unit cell. Marbles and spherical magnets are employed to prepare each stacking arrangement. Packing…

  13. Corrugated Membrane Fuel Cell Structures

    Energy Technology Data Exchange (ETDEWEB)

    Grot, Stephen [President, Ion Power Inc.

    2013-09-30

    One of the most challenging aspects of traditional PEM fuel cell stacks is the difficulty achieving the platinum catalyst utilization target of 0.2 gPt/kWe set forth by the DOE. Good catalyst utilization can be achieved with state-of-the-art catalyst coated membranes (CCM) when low catalyst loadings (<0.3 mg/cm2) are used at a low current. However, when low platinum loadings are used, the peak power density is lower than conventional loadings, requiring a larger total active area and a larger bipolar plate. This results in a lower overall stack power density not meeting the DOE target. By corrugating the fuel cell membrane electrode structure, Ion Power?s goal is to realize both the Pt utilization targets as well as the power density targets of the DOE. This will be achieved by demonstrating a fuel cell single cell (50 cm2) with a twofold increase in the membrane active area over the geometric area of the cell by corrugating the MEA structure. The corrugating structure must be able to demonstrate the target properties of < 10 mOhm-cm2 electrical resistance at > 20 psi compressive strength over the active area, in combination with offering at least 80% of power density that can be achieved by using the same MEA in a flat plate structure. Corrugated membrane fuel cell structures also have the potential to meet DOE power density targets by essentially packaging more membrane area into the same fuel cell volume as compared to conventional stack constructions.

  14. How acidic are monomeric structural units of heparin?

    Science.gov (United States)

    Remko, Milan; Broer, Ria; Van Duijnen, Piet Th.

    2013-12-01

    Density functional theory methods with the B3LYP functional have been used to letter the acidity of carboxyl, O-sulfo and N-sulfo groups in six basic monomeric structural units of heparin (1-OMe ΔUA-2S, 1-OMe GlcN-S6S, 1,4-DiOMe GlcA, 1,4-DiOMe GlcN-S3S6S, 1,4-DiOMe IdoA-2S, and 1,4-DiOMe GlcN-S6S). The predicted gas-phase acidity of the acidic functional groups in the monomeric structural units of heparin is: O-sulfo > N-sulfo > carboxyl. The computed pKa values provide the same order of acidity as was observed in water solution. This implies that hydration does not change ordering of acidity of major acidic groups of monomeric structural units of heparin.

  15. Structure determines medication errors in nursing units: a mechanistic approach.

    Science.gov (United States)

    Hung, Chang-Chiao; Lee, Bih-O; Tsai, Shu-Ling; Tseng, Yun Shan; Chang, Chia-Hao

    2015-03-01

    Medication errors have long been considered critical in global health care systems. However, few studies have been conducted to explore the effects of nursing unit structure on medication errors. The purpose of this study, therefore, was to determine the effects of structural factors on medication errors in nursing units. A total of 977 staff nurses and 62 head nurses participated in this cross-sectional design study. The findings show that professional autonomy (β = .53, t = 6.03, p nursing experts (β = .52, t = 5.99, p medication error rates. This study shows that the structural factors influence medication administration and the mechanistic approach is specifically in relation of low medication error rates. The author suggests that head nurses should consider strategies that require adjustments to unit control mechanisms.

  16. Cell Churches and Stem Cell Marketing in South Korea and the United States.

    Science.gov (United States)

    Sipp, Douglas

    2016-05-23

    The commercial provision of putative stem cell-based medical interventions in the absence of conclusive evidence of safety and efficacy has formed the basis of an unregulated industry for more than a decade. Many clinics offering such supposed stem cell treatments include statements about the 'ethical' nature of somatic (often colloquially referred to as 'adult' stem cells) stem cells, in specific contrast to human embryonic stem cells (hESCs), which have been the subject of intensive political, legal, and religious controversy since their first derivation in 1998. Christian groups-both Roman Catholic and evangelical Protestant-in many countries have explicitly promoted the medical potential and current-day successes in the clinical application of somatic stem cells, lending indirect support to the activities of businesses marketing stem cells ahead of evidence. In this article, I make a preliminary examination of how the structures and belief systems of certain churches in South Korea and the United States, both of which are home to significant stem cell marketing industries, has complemented other factors, including national biomedical funding initiatives, international economic rivalries, permissive legal structures, which have lent impetus to a problematic and often exploitative sector of biomedical commerce.

  17. Structural Evaluation of the Second Oldest Glued-Laminated Structure in the United States

    Science.gov (United States)

    Douglas R. Rammer; Jorge de Melo Moura

    2013-01-01

    The second glued-laminated structure built in the United States was constructed at the USDA Forest Products Laboratory (FPL) in 1934 to demonstrate the performance of wooden arch buildings. After decades of use the structure was decommissioned in 2010. Shortly after construction, researchers structurally evaluated the glued-laminated arch structure for uniform loading...

  18. Modeling cell-in-cell structure into its biological significance

    OpenAIRE

    He, M-f; Wang, S.; Wang, Y; Wang, X-N.

    2013-01-01

    Although cell-in-cell structure was noted 100 years ago, the molecular mechanisms of ‘entering' and the destination of cell-in-cell remain largely unclear. It takes place among the same type of cells (homotypic cell-in-cell) or different types of cells (heterotypic cell-in-cell). Cell-in-cell formation affects both effector cells and their host cells in multiple aspects, while cell-in-cell death is under more intensive investigation. Given that cell-in-cell has an important role in maintainin...

  19. Types of structural unemployment in the United Kingdom.

    Science.gov (United States)

    Hart, P E

    1990-01-01

    The author assesses the importance of each classification of "structural unemployment, namely technological, mismatch of skills, geographical mismatch, demographic shifts, institutional rigidities, 'unemployability', and capital-restructuring unemployment." in the United Kingdom. He also reviews recent evidence on regional wage differential adjustments and their impact on the disequilibrium within the British labor market.

  20. The structure and function of fungal cells

    Science.gov (United States)

    Nozawa, Y.

    1984-01-01

    The structure and function of fungal cell walls were studied with particular emphasis on dermatophytes. Extraction, isolation, analysis, and observation of the cell wall structure and function were performed. The structure is described microscopically and chemically.

  1. Structural racism and myocardial infarction in the United States.

    Science.gov (United States)

    Lukachko, Alicia; Hatzenbuehler, Mark L; Keyes, Katherine M

    2014-02-01

    There is a growing research literature suggesting that racism is an important risk factor undermining the health of Blacks in the United States. Racism can take many forms, ranging from interpersonal interactions to institutional/structural conditions and practices. Existing research, however, tends to focus on individual forms of racial discrimination using self-report measures. Far less attention has been paid to whether structural racism may disadvantage the health of Blacks in the United States. The current study addresses gaps in the existing research by using novel measures of structural racism and by explicitly testing the hypothesis that structural racism is a risk factor for myocardial infarction among Blacks in the United States. State-level indicators of structural racism included four domains: (1) political participation; (2) employment and job status; (3) educational attainment; and (4) judicial treatment. State-level racial disparities across these domains were proposed to represent the systematic exclusion of Blacks from resources and mobility in society. Data on past-year myocardial infarction were obtained from the National Epidemiologic Survey on Alcohol and Related Conditions (non-Hispanic Black: N = 8245; non-Hispanic White: N = 24,507), a nationally representative survey of the U.S. civilian, non-institutionalized population aged 18 and older. Models were adjusted for individual-level confounders (age, sex, education, household income, medical insurance) as well as for state-level disparities in poverty. Results indicated that Blacks living in states with high levels of structural racism were generally more likely to report past-year myocardial infarction than Blacks living in low-structural racism states. Conversely, Whites living in high structural racism states experienced null or lower odds of myocardial infarction compared to Whites living in low-structural racism states. These results raise the provocative possibility that structural

  2. Units of analysis and kinetic structure of behavioral repertoires.

    Science.gov (United States)

    Thompson, T; Lubinski, D

    1986-09-01

    It is suggested that molar streams of behavior are constructed of various arrangements of three elementary constituents (elicited, evoked, and emitted response classes). An eight-cell taxonomy is elaborated as a framework for analyzing and synthesizing complex behavioral repertoires based on these functional units. It is proposed that the local force binding functional units into a smoothly articulated kinetic sequence arises from temporally arranged relative response probability relationships. Behavioral integration is thought to reflect the joint influence of the organism's hierarchy of relative response probabilities, fluctuating biological states, and the arrangement of environmental and behavioral events in time.

  3. Assessment of teamwork during structured interdisciplinary rounds on medical units.

    Science.gov (United States)

    O'Leary, Kevin J; Boudreau, Yvonne N; Creden, Amanda J; Slade, Maureen E; Williams, Mark V

    2012-01-01

    Interdisciplinary rounds (IDR) provide a means to assemble hospital team members and improve collaboration. Little is known about teamwork during IDR. To evaluate and characterize teamwork during IDR. Cross-sectional observational study. Six medical units which had implemented structured interdisciplinary rounds (SIDR). We adapted the Observational Teamwork Assessment for Surgery (OTAS) tool, a behaviorally anchored rating scale shown to be reliable and valid in surgical settings. OTAS provides scores ranging from 0 to 6 (0 = problematic behavior; 6 = exemplary behavior) across 5 domains (communication, coordination, cooperation/backup behavior, leadership, and monitoring/situational awareness) and for prespecified subteams. Two researchers conducted direct observations using the adapted OTAS tool. We conducted 7-8 independent observations for each unit (total = 44) and 20 joint observations. Inter-rater reliability was excellent at the unit level (Spearman's rho = 0.75), and good across domains (rho = 0.53-0.68) and subteams (rho = 0.53-0.76) with the exception of the physician subteam, for which it was poor (rho = 0.35). Though teamwork scores were generally high, we found differences across units, with a median (interquartile range [IQR]) 4.5 (3.9-4.9) for the lowest and 5.4 (5.3-5.5) for the highest performing unit (P teamwork during SIDR across units, domains, and most subteams. Variation in performance suggests a need to improve consistency of teamwork and emphasizes the importance of leadership. Copyright © 2012 Society of Hospital Medicine.

  4. Topological Quantization in Units of the Fine Structure Constant

    Energy Technology Data Exchange (ETDEWEB)

    Maciejko, Joseph; /Stanford U., Phys. Dept. /Stanford U., Materials Sci. Dept. /SLAC; Qi, Xiao-Liang; /Station Q, UCSB /Stanford U., Phys. Dept. /Stanford U., Materials Sci. Dept. /SLAC; Drew, H.Dennis; /Maryland U.; Zhang, Shou-Cheng; /Stanford U., Phys. Dept. /Stanford U., Materials Sci. Dept. /SLAC

    2011-11-11

    Fundamental topological phenomena in condensed matter physics are associated with a quantized electromagnetic response in units of fundamental constants. Recently, it has been predicted theoretically that the time-reversal invariant topological insulator in three dimensions exhibits a topological magnetoelectric effect quantized in units of the fine structure constant {alpha} = e{sup 2}/{h_bar}c. In this Letter, we propose an optical experiment to directly measure this topological quantization phenomenon, independent of material details. Our proposal also provides a way to measure the half-quantized Hall conductances on the two surfaces of the topological insulator independently of each other.

  5. Optimum Structural Design of a Chain-Driving Pumping Unit

    Institute of Scientific and Technical Information of China (English)

    Zhang Ailin; Liu Yang

    1994-01-01

    @@ Operating Principle and Essential Parameters In this paper the pumping unit of type QLCJ14-6 is studied. Through the belt driving unit, the motor drives the driving sprocket in which the rotation rate has been reduced by the reduction gearbox.The locus chain moves between the driving sprocket and upper sprocket which are vertically set. There's a special chain element in the locus chain, which drives the reciprocating holster with the main shaft linchpin and slide block. The reciprocating holster could only move up and down when the locus chain moves in a circle. In this way the up and down stroke of the sucker rod and the machine is realized.The lower end of the reciprocating holster is connected with the equilibrium system to make the structure balance. The balancing cylinder is replaced by the balancing block to make the structure simplified.

  6. Fabrication and characteristics of unit cell for SOFC

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Gwi-Yeol; Eom, Seung-Wook; Moon, Seong-In [Korea Electrotechnology Research Institute, Kyongnam (Korea, Republic of)] [and others

    1996-12-31

    Research and development on solid oxide fuel cells in Korea have been mainly focused on unit cell and small stack. Fuel cell system is called clean generation system which not cause NOx or SOx. It is generation efficiency come to 50-60% in contrast to 40% of combustion generation system. Among the fuel cell system, solid oxide fuel cell is constructed of ceramics, so stack construction is simple, power density is very high, and there are no corrosion problems. The object of this study is to develop various composing material for SOFC generation system, and to test unit cell performance manufactured. So we try to present a guidance for developing mass power generation system. We concentrated on development of manufacturing process for cathode, anode and electrolyte.

  7. Process and structure: resource management and the development of sub-unit organisational structure.

    Science.gov (United States)

    Packwood, T; Keen, J; Buxton, M

    1992-03-01

    Resource Management (RM) requires hospital units to manage their work in new ways, and the new management processes affect, and are affected by, organisation structure. This paper is concerned with these effects, reporting on the basis of a three-year evaluation of the national RM experiment that was commissioned by the DH. After briefly indicating some of the major characteristics of the RM process, the two main types of unit structures existing in the pilot sites at the beginning of the experiment, unit disciplinary structure and clinical directorates, are analysed. At the end of the experiment, while clinical directorates had become more popular, another variant, clinical grouping, had replaced the unit disciplinary structure. Both types of structure represent a movement towards sub-unit organisation, bringing the work and interests of the service providers and unit managers closer together. Their properties are likewise analysed and their implications, particularly in terms of training and organisational development (OD), are then considered. The paper concludes by considering the causes for these structural changes, which, in the immediate time-scale, appear to owe as much to the NHS Review as to RM.

  8. The Application of Load-cell Technique in the Study of Armour Unit Responses to Impact Loads Tests

    DEFF Research Database (Denmark)

    Burcharth, H. F.; Liu, Z.

    1995-01-01

    The slender, complex types of armour units, such as Tetrapods and Dolosse are widely used for rubble mound breakwaters. Many of the recent failures of such structures were caused by unforeseen early breakage of the units, thus revealing an in balance between the strength (structural integrity....... slender armour units can be studied. by load-cell technique. Moreover, the paper presents DoJos design diagrams for the prediction of both breakage and hydraulic stability...

  9. The Application of Load-cell Technique in the Study of Armour Unit Responses to Impact Loads

    DEFF Research Database (Denmark)

    Burcharth, H. F.; Liu, Zhou

    1994-01-01

    The slender, complex types of armour units, such as Tetrapods and Dolosse are widely used for rubble mound breakwaters. Many of the recent failures of such structures were caused by unforeseen early breakage of the units, thus revealing an inbalance between the strength (structural integrity...... on slender armour units can be studied by load-cell technique. Moreover, the paper presents Dolos design diagrams for the prediction of both breakage and hydraulic stability....

  10. 3D-Printing Crystallographic Unit Cells for Learning Materials Science and Engineering

    Science.gov (United States)

    Rodenbough, Philip P.; Vanti, William B.; Chan, Siu-Wai

    2015-01-01

    Introductory materials science and engineering courses universally include the study of crystal structure and unit cells, which are by their nature highly visual 3D concepts. Traditionally, such topics are explored with 2D drawings or perhaps a limited set of difficult-to-construct 3D models. The rise of 3D printing, coupled with the wealth of…

  11. 3D-Printing Crystallographic Unit Cells for Learning Materials Science and Engineering

    Science.gov (United States)

    Rodenbough, Philip P.; Vanti, William B.; Chan, Siu-Wai

    2015-01-01

    Introductory materials science and engineering courses universally include the study of crystal structure and unit cells, which are by their nature highly visual 3D concepts. Traditionally, such topics are explored with 2D drawings or perhaps a limited set of difficult-to-construct 3D models. The rise of 3D printing, coupled with the wealth of…

  12. Super Unit Cells in Aperture-Based Metamaterials

    Directory of Open Access Journals (Sweden)

    Dragan Tanasković

    2015-01-01

    Full Text Available An important class of electromagnetic metamaterials are aperture-based metasurfaces. Examples include extraordinary optical transmission arrays and double fishnets with negative refractive index. We analyze a generalization of such metamaterials where a simple aperture is now replaced by a compound object formed by superposition of two or more primitive objects (e.g., rectangles, circles, and ellipses. Thus obtained “super unit cell” shows far richer behavior than the subobjects that comprise it. We show that nonlocalities introduced by overlapping simple subobjects can be used to produce large deviations of spectral dispersion even for small additive modifications of the basic geometry. Technologically, some super cells may be fabricated by simple spatial shifting of the existing photolithographic masks. In our investigation we applied analytical calculations and ab initio finite element modeling to prove the possibility to tailor the dispersion including resonances for plasmonic nanocomposites by adjusting the local geometry and exploiting localized interactions at a subwavelength level. Any desired form could be defined using simple primitive objects, making the situation a geometrical analog of the case of series expansion of a function. Thus an additional degree of tunability of metamaterials is obtained. The obtained designer structures can be applied in different fields like waveguiding and sensing.

  13. Learning about the Unit Cell and Crystal Lattice with Computerized Simulations and Games: A Pilot Study

    Science.gov (United States)

    Luealamai, Sutha; Panijpan, Bhinyo

    2012-01-01

    The authors have developed a computer-based learning module on the unit cell of various types of crystal. The module has two components: the virtual unit cell (VUC) part and the subsequent unit cell hunter part. The VUC is a virtual reality simulation for students to actively arrive at the unit cell from exploring, from a broad view, the crystal…

  14. Learning about the Unit Cell and Crystal Lattice with Computerized Simulations and Games: A Pilot Study

    Science.gov (United States)

    Luealamai, Sutha; Panijpan, Bhinyo

    2012-01-01

    The authors have developed a computer-based learning module on the unit cell of various types of crystal. The module has two components: the virtual unit cell (VUC) part and the subsequent unit cell hunter part. The VUC is a virtual reality simulation for students to actively arrive at the unit cell from exploring, from a broad view, the crystal…

  15. Polymer electrolyte fuel cell mini power unit for portable application

    Science.gov (United States)

    Urbani, F.; Squadrito, G.; Barbera, O.; Giacoppo, G.; Passalacqua, E.; Zerbinati, O.

    This paper describes the design, realisation and test of a power unit based on a polymer electrolyte fuel cell, operating at room temperature, for portable application. The device is composed of an home made air breathing fuel cell stack, a metal hydride tank for H 2 supply, a dc-dc converter for power output control and a fan for stack cooling. The stack is composed by 10 cells with an active surface of 25 cm 2 and produces a rated power of 15 W at 6 V and 2 A. The stack successfully runs with end-off fed hydrogen without appreciable performance degradation during the time. The final assembled system is able to generate 12 W at 9.5 V, and power a portable DVD player for 3 h in continuous. The power unit has collected about 100 h of operation without maintenance.

  16. Polymer electrolyte fuel cell mini power unit for portable application

    Energy Technology Data Exchange (ETDEWEB)

    Urbani, F.; Squadrito, G.; Barbera, O.; Giacoppo, G.; Passalacqua, E. [CNR-ITAE, via Salita S. Lucia sopra Contesse n. 5, 98126 S. Lucia, Messina (Italy); Zerbinati, O. [Universita del Piemonte Orientale, Dip. di Scienze dell' Ambiente e della Vita, via Bellini 25/g, 15100 Alessandria (Italy)

    2007-06-20

    This paper describes the design, realisation and test of a power unit based on a polymer electrolyte fuel cell, operating at room temperature, for portable application. The device is composed of an home made air breathing fuel cell stack, a metal hydride tank for H{sub 2} supply, a dc-dc converter for power output control and a fan for stack cooling. The stack is composed by 10 cells with an active surface of 25 cm{sup 2} and produces a rated power of 15 W at 6 V and 2 A. The stack successfully runs with end-off fed hydrogen without appreciable performance degradation during the time. The final assembled system is able to generate 12 W at 9.5 V, and power a portable DVD player for 3 h in continuous. The power unit has collected about 100 h of operation without maintenance. (author)

  17. Studies of the Temperature Characteristics of Solid at the Microlevel by the Method of Structural Units

    Directory of Open Access Journals (Sweden)

    A.A. Mochalov

    2014-11-01

    Full Text Available The mathematical model of the heat transfer process based on the structural unit method is proposed. Calculation results of the model equations of thermodynamic characteristics of structural unit for solids are represented.

  18. Structure and functions of fungal cell surfaces

    Science.gov (United States)

    Nozawa, Y.

    1984-01-01

    A review with 24 references on the biochemistry, molecular structure, and function of cell surfaces of fungi, especially dermatophytes: the chemistry and structure of the cell wall, the effect of polyene antibiotics on the morphology and function of cytoplasmic membranes, and the chemical structure and function of pigments produced by various fungi are discussed.

  19. Amino Acid Molecular Units: Building Primary and Secondary Protein Structures

    Directory of Open Access Journals (Sweden)

    Aparecido R. Silva

    2008-05-01

    Full Text Available In order to guarantee the learning quality and suitable knowledge  use  about structural biology, it is fundamental to  exist, since the beginning of  students’ formation, the possibility of clear visualization of biomolecule structures. Nevertheless, the didactic books can only bring  schematic  drawings; even more elaborated figures and graphic computation  do not permit the necessary interaction.  The representation of three-dimensional molecular structures with ludic models, built with representative units, have supplied to the students and teachers a successfully experience to  visualize such structures and correlate them to the real molecules.  The design and applicability of the representative units were discussed with researchers and teachers before mould implementation.  In this stage  it  will be presented the  developed  kit  containing the  representative  plastic parts of the main amino acids.  The kit can demonstrate the interaction among the amino acids  functional groups  (represented by colors, shapes,  sizes and  the peptidic bonds between them  facilitating the assembly and visuali zation of the primary and secondary protein structure.  The models were designed for  Ca,  amino,  carboxyl groups  and  hydrogen. The  lateral chains have  well defined models that represent their geometrical shape.  The completed kit set  will be presented in this meeting (patent requested.  In the last phase of the project will be realized  an effective evaluation  of the kit  as a facilitative didactic tool of the teaching/learning process in the Structural Molecular Biology area.

  20. Microbial fuel cells as pollutant treatment units: Research updates.

    Science.gov (United States)

    Zhang, Quanguo; Hu, Jianjun; Lee, Duu-Jong

    2016-10-01

    Microbial fuel cells (MFC) are a device that can convert chemical energy in influent substances to electricity via biological pathways. Based on the consent that MFC technology should be applied as a waste/wastewater treatment unit rather than a renewable energy source, this mini-review discussed recent R&D efforts on MFC technologies for pollutant treatments and highlighted the challenges and research and development needs. Owing to the low power density levels achievable by larger-scale MFC, the MFC should be used as a device other than energy source such as being a pollutant treatment unit.

  1. Mechanical properties of regular porous biomaterials made from truncated cube repeating unit cells: Analytical solutions and computational models.

    Science.gov (United States)

    Hedayati, R; Sadighi, M; Mohammadi-Aghdam, M; Zadpoor, A A

    2016-03-01

    Additive manufacturing (AM) has enabled fabrication of open-cell porous biomaterials based on repeating unit cells. The micro-architecture of the porous biomaterials and, thus, their physical properties could then be precisely controlled. Due to their many favorable properties, porous biomaterials manufactured using AM are considered as promising candidates for bone substitution as well as for several other applications in orthopedic surgery. The mechanical properties of such porous structures including static and fatigue properties are shown to be strongly dependent on the type of the repeating unit cell based on which the porous biomaterial is built. In this paper, we study the mechanical properties of porous biomaterials made from a relatively new unit cell, namely truncated cube. We present analytical solutions that relate the dimensions of the repeating unit cell to the elastic modulus, Poisson's ratio, yield stress, and buckling load of those porous structures. We also performed finite element modeling to predict the mechanical properties of the porous structures. The analytical solution and computational results were found to be in agreement with each other. The mechanical properties estimated using both the analytical and computational techniques were somewhat higher than the experimental data reported in one of our recent studies on selective laser melted Ti-6Al-4V porous biomaterials. In addition to porosity, the elastic modulus and Poisson's ratio of the porous structures were found to be strongly dependent on the ratio of the length of the inclined struts to that of the uninclined (i.e. vertical or horizontal) struts, α, in the truncated cube unit cell. The geometry of the truncated cube unit cell approaches the octahedral and cube unit cells when α respectively approaches zero and infinity. Consistent with those geometrical observations, the analytical solutions presented in this study approached those of the octahedral and cube unit cells when

  2. Malfunction analysis of OPGW of stainless steel-unit structure

    Institute of Scientific and Technical Information of China (English)

    李星梅; 张素芳; 王旭锋; 乞建勋

    2008-01-01

    Composite fiber optic overhead ground wire (OPGW) is increasingly applied in China’s overhead transmission lines. The stainless steel structure is adopted by most OPGWs as it is very small and easy to match the existing ground wire. The malfunction of OPGW in Beijing-Shanghai Optical Communication Project was analyzed through the chemical composition method and spectrum semi-quantitative method. The analysis indicates that the cable fault was due to the failure of seepage and irregular holes in the steel pipe of the optical unit. The rain water and the watery air entered into the optical units, and the water in turn became ice when temperature dropped. The occurrence of ice led to the acceleration of attenuation of the fiber. The results show that the rupture of stainless steel tube is mainly due to the instability of welding technique. The malfunction of OPGW is due to the local defects of welding seam because of local stress concentration in the manufacturing process.

  3. Orthographic units in the absence of visual processing: Evidence from sublexical structure in braille.

    Science.gov (United States)

    Fischer-Baum, Simon; Englebretson, Robert

    2016-08-01

    Reading relies on the recognition of units larger than single letters and smaller than whole words. Previous research has linked sublexical structures in reading to properties of the visual system, specifically on the parallel processing of letters that the visual system enables. But whether the visual system is essential for this to happen, or whether the recognition of sublexical structures may emerge by other means, is an open question. To address this question, we investigate braille, a writing system that relies exclusively on the tactile rather than the visual modality. We provide experimental evidence demonstrating that adult readers of (English) braille are sensitive to sublexical units. Contrary to prior assumptions in the braille research literature, we find strong evidence that braille readers do indeed access sublexical structure, namely the processing of multi-cell contractions as single orthographic units and the recognition of morphemes within morphologically-complex words. Therefore, we conclude that the recognition of sublexical structure is not exclusively tied to the visual system. However, our findings also suggest that there are aspects of morphological processing on which braille and print readers differ, and that these differences may, crucially, be related to reading using the tactile rather than the visual sensory modality.

  4. Zero loss magnetic metamaterials using powered active unit cells.

    Science.gov (United States)

    Yuan, Yu; Popa, Bogdan-Ioan; Cummer, Steven A

    2009-08-31

    We report the design and experimental measurement of a powered active magnetic metamaterial with tunable permeability. The unit cell is based on the combination of an embedded radiofrequency amplifier and a tunable phase shifter, which together control the response of the medium. The measurements show that a negative permeability metamaterial with zero loss or even gain can be achieved through an array of such metamaterial cells. This kind of active metamaterial can find use in applications that are performance limited due to material losses.

  5. A heated vapor cell unit for DAVLL in atomic rubidium

    OpenAIRE

    McCarron, Daniel J.; Hughes, Ifan G.; Tierney, Patrick; Cornish, Simon L

    2007-01-01

    The design and performance of a compact heated vapor cell unit for realizing a dichroic atomic vapor laser lock (DAVLL) for the D2 transitions in atomic rubidium is described. A 5 cm-long vapor cell is placed in a double-solenoid arrangement to produce the required magnetic field; the heat from the solenoid is used to increase the vapor pressure and correspondingly the DAVLL signal. We have characterized experimentally the dependence of important features of the DAVLL signal on magnetic field...

  6. Composite Bipolar Plate for Unitized Fuel Cell/Electrolyzer Systems

    Science.gov (United States)

    Mittelsteadt, Cortney K.; Braff, William

    2009-01-01

    In a substantial improvement over present alkaline systems, an advanced hybrid bipolar plate for a unitized fuel cell/electrolyzer has been developed. This design, which operates on pure feed streams (H2/O2 and water, respectively) consists of a porous metallic foil filled with a polymer that has very high water transport properties. Combined with a second metallic plate, the pore-filled metallic plates form a bipolar plate with an empty cavity in the center.

  7. Solid Oxide Fuel Cells coupled with a biomass gasification unit

    Directory of Open Access Journals (Sweden)

    Skrzypkiewicz Marek

    2016-01-01

    Full Text Available A possibility of fuelling a solid oxide fuel cell stack (SOFC with biomass fuels can be realized by coupling a SOFC system with a self-standing gasification unit. Such a solution enables multi-fuel operation, elasticity of the system as well as the increase of the efficiency of small-scale biomass-to-electricity conversion units. A system of this type, consisting of biomass gasification unit, gas purification unit, SOFC stack, anode off-gas afterburner and peripherals was constructed and operated successfully. During the process, biomass fuel (wood chips was gasified with air as gasification agent. The gasifier was capable of converting up to 30 kW of fuel to syngas with efficiencies up to 75%. Syngas leaving the gasification unit is delivered to a medium temperature adsorber for sulphur compounds removal. Steam is added to the purified fuel to maintain steam to carbon ratio higher than 2. The syngas then is passed to a SOFC stack through a fuel preheater. In such a configuration it was possible to operate a commercial 1.3 kW stack within its working regime. Conducted tests confirmed successful operation of a SOFC stack fuelled by biomass-sourced syngas.

  8. Thermodynamics of Condensed Phases: Formula Unit Volume, "V[subscript m]", and the Determination of the Number of Formula Units, "Z", in a Crystallographic Unit Cell

    Science.gov (United States)

    Glasser, Leslie

    2011-01-01

    Formula unit (or molecular) volume, "V[subscript m]", is related to many thermodynamic and physical properties of materials, so that knowledge of "V[subscript m]" is useful in prediction of such properties for known and even hypothetical materials. The symbol "Z" represents the number of formula units in a crystallographic unit cell; "Z" thus…

  9. BioDiff - a neutron diffractometer optimized for crystals with large unit cell dimensions

    OpenAIRE

    Schrader, Tobias Erich; Ostermann, Andreas; Monkenbusch, Michael; Laatsch, Bernhard; Jüttner, Philipp; Petry, Winfried; Richter, Dieter

    2014-01-01

    The research reactor Heinz Maier-Leibnitz (FRM II) is a modern high flux neutron source which feeds some 30 state of the art neutron beam instruments. Currently 24 are operational, others in commissioning or under construction. The newly built neutron single crystal diffractometer BIODIFF is especially designed to collect data from crystals with large unit cells. The main field of application is the structural analysis of proteins, especially the determination of hydrogen atom positions. BIOD...

  10. Teaching Three-Dimensional Structural Chemistry Using Crystal Structure Databases. 2. Teaching Units that Utilize an Interactive Web-Accessible Subset of the Cambridge Structural Database

    Science.gov (United States)

    Battle, Gary M.; Allen, Frank H.; Ferrence, Gregory M.

    2010-01-01

    A series of online interactive teaching units have been developed that illustrate the use of experimentally measured three-dimensional (3D) structures to teach fundamental chemistry concepts. The units integrate a 500-structure subset of the Cambridge Structural Database specially chosen for their pedagogical value. The units span a number of key…

  11. Zeroing in on red blood cell unit expiry.

    Science.gov (United States)

    Ayyalil, Fathima; Irwin, Greg; Ross, Bryony; Manolis, Michael; Enjeti, Anoop K

    2017-09-20

    Expiry of red blood cell (RBC) units is a significant contributor to wastage of precious voluntary donations. Effective strategies aimed at optimal resource utilization are required to minimize wastage. This retrospective study analyzed the strategic measures implemented to reduce expiry of RBC units in an Australian tertiary regional hospital. The measures, which included inventory rearrangement, effective stock rotation, and the number of emergency courier services required during a 24-month period, were evaluated. There was no wastage of RBC units due to expiry over the 12 months after policy changes. Before these changes, approximately half of RBC wastage (261/511) was due to expiry. The total number of transfusions remained constant in this period and there was no increase in the use of emergency couriers. Policy changes implemented were decreasing the RBC inventory level by one-third and effective stock rotation and using a computerized system to link the transfusion services across the area. Effective stock rotation resulted in a reduction in older blood (>28 days) received in the main laboratory rotated from peripheral hospitals, down from 6%-41% to 0%-2.5%. Age-related expiry of blood products is preventable and can be significantly reduced by improving practices in the pathology service. This study provides proof of principle for "zero tolerance for RBC unit expiry" across a large networked blood banking service. © 2017 The Authors Transfusion published by Wiley Periodicals, Inc. on behalf of AABB.

  12. Inulin isoforms differ by repeated additions of one crystal unit cell.

    Science.gov (United States)

    Cooper, Peter D; Barclay, Thomas G; Ginic-Markovic, Milena; Gerson, Andrea R; Petrovsky, Nikolai

    2014-03-15

    Inulin isoforms, especially delta inulin, are important biologically as immune activators and clinically as vaccine adjuvants. In exploring action mechanisms, we previously found regular increments in thermal properties of the seven-member inulin isoform series that suggested regular additions of some energetic structural unit. Because the previous isolates carried additional longer chains that masked defining ranges, these were contrasted with new isoform isolates comprising only inulin chain lengths defining that isoform. The new series began with 19 fructose units per chain (alpha-1 inulin), increasing regularly by 6 fructose units per isoform. Thus the 'energetic unit' equates to 6 fructose residues per chain. All isoforms showed indistinguishable X-ray diffraction patterns that were also identical with known inulin crystals. We conclude that an 'energetic unit' equates to one helix turn of 6 fructose units per chain as found in one unit cell of the inulin crystal. Each isoform chain comprised progressively more helix turns plus one additional fructose and glucose residues per chain.

  13. Structure of the Elastin-Contractile Units in the Thoracic Aorta and How Genes That Cause Thoracic Aortic Aneurysms and Dissections Disrupt This Structure.

    Science.gov (United States)

    Karimi, Ashkan; Milewicz, Dianna M

    2016-01-01

    The medial layer of the aorta confers elasticity and strength to the aortic wall and is composed of alternating layers of smooth muscle cells (SMCs) and elastic fibres. The SMC elastin-contractile unit is a structural unit that links the elastin fibres to the SMCs and is characterized by the following: (1) layers of elastin fibres that are surrounded by microfibrils; (2) microfibrils that bind to the integrin receptors in focal adhesions on the cell surface of the SMCs; and (3) SMC contractile filaments that are linked to the focal adhesions on the inner side of the membrane. The genes that are altered to cause thoracic aortic aneurysms and aortic dissections encode proteins involved in the structure or function of the SMC elastin-contractile unit. Included in this gene list are the genes encoding protein that are structural components of elastin fibres and microfibrils, FBN1, MFAP5, ELN, and FBLN4. Also included are genes that encode structural proteins in the SMC contractile unit, including ACTA2, which encodes SMC-specific α-actin and MYH11, which encodes SMC-specific myosin heavy chain, along with MYLK and PRKG1, which encode kinases that control SMC contraction. Finally, mutations in the gene encoding the protein linking integrin receptors to the contractile filaments, FLNA, also predispose to thoracic aortic disease. Thus, these data suggest that functional SMC elastin-contractile units are important for maintaining the structural integrity of the aorta.

  14. Accelerating VASP electronic structure calculations using graphic processing units

    KAUST Repository

    Hacene, Mohamed

    2012-08-20

    We present a way to improve the performance of the electronic structure Vienna Ab initio Simulation Package (VASP) program. We show that high-performance computers equipped with graphics processing units (GPUs) as accelerators may reduce drastically the computation time when offloading these sections to the graphic chips. The procedure consists of (i) profiling the performance of the code to isolate the time-consuming parts, (ii) rewriting these so that the algorithms become better-suited for the chosen graphic accelerator, and (iii) optimizing memory traffic between the host computer and the GPU accelerator. We chose to accelerate VASP with NVIDIA GPU using CUDA. We compare the GPU and original versions of VASP by evaluating the Davidson and RMM-DIIS algorithms on chemical systems of up to 1100 atoms. In these tests, the total time is reduced by a factor between 3 and 8 when running on n (CPU core + GPU) compared to n CPU cores only, without any accuracy loss. © 2012 Wiley Periodicals, Inc.

  15. Unit cell-based computer-aided manufacturing system for tissue engineering.

    Science.gov (United States)

    Kang, Hyun-Wook; Park, Jeong Hun; Kang, Tae-Yun; Seol, Young-Joon; Cho, Dong-Woo

    2012-03-01

    Scaffolds play an important role in the regeneration of artificial tissues or organs. A scaffold is a porous structure with a micro-scale inner architecture in the range of several to several hundreds of micrometers. Therefore, computer-aided construction of scaffolds should provide sophisticated functionality for porous structure design and a tool path generation strategy that can achieve micro-scale architecture. In this study, a new unit cell-based computer-aided manufacturing (CAM) system was developed for the automated design and fabrication of a porous structure with micro-scale inner architecture that can be applied to composite tissue regeneration. The CAM system was developed by first defining a data structure for the computing process of a unit cell representing a single pore structure. Next, an algorithm and software were developed and applied to construct porous structures with a single or multiple pore design using solid freeform fabrication technology and a 3D tooth/spine computer-aided design model. We showed that this system is quite feasible for the design and fabrication of a scaffold for tissue engineering.

  16. Replication domains are self-interacting structural chromatin units of human chromosomes

    Science.gov (United States)

    Arneodo, Alain

    2011-03-01

    In higher eukaryotes, the absence of specific sequence motifs marking the origins of replication has been a serious hindrance to the understanding of the mechanisms that regulate the initiation and the maintenance of the replication program in different cell types. In silico analysis of nucleotide compositional skew has predicted the existence, in the germline, of replication N-domains bordered by putative replication origins and where the skew decreases rather linearly as the signature of a progressive inversion of the average fork polarity. Here, from the demonstration that the average fork polarity can be directly extracted from the derivative of replication timing profiles, we develop a wavelet-based pattern recognition methodology to delineate replication U-domains where the replication timing profile is shaped as a U and its derivative as a N. Replication U-domains are robustly found in seven cell lines as covering a significant portion (40-50%) of the human genome where the replication timing data actually displays some plasticity between cell lines. The early replication initiation zones at U-domains borders are found to be hypersensitive to DNase I cleavage, to be associated with transcriptional activity and to present a significant enrichment in insular-binding proteins CTCF, the hallmark of an open chromatin structure. A comparative analysis of genome-wide chromatin interaction (HiC) data shows that replication-U domains correspond to self-interacting structural high order chromatin units of megabase characteristic size. Taken together, these findings provide evidence that the epigenetic compartmentalization of the human genome into autonomous replication U-domains comes along with an extensive remodelling of the threedimensional chromosome architecture during development or in specific diseases. The observed cell specific conservation of the replication timing between the human and mouse genomes strongly suggests that this chromosome organization into

  17. Structure of the Elastin-Contractile Units in the Thoracic Aorta and How Genes that Cause Thoracic Aortic Aneurysms and Dissections Disrupt this Structure

    OpenAIRE

    Karimi, Ashkan; Milewicz, Dianna M.

    2015-01-01

    The medial layer of the aorta confers elasticity and strength to the aortic wall and is composed of alternating layers of smooth muscle cells (SMCs) and elastic fibers. The SMC elastin-contractile unit is a structural unit that links the elastin fibers to the SMCs and is characterized by the following: 1. Layers of elastin fibers that are surrounded by microfibrils. 2. Microfibrils that bind to the integrin receptors in focal adhesions on the cell surface of the SMCs. 3. SMC contractile filam...

  18. Cell Secretion: Current Structural and Biochemical Insights

    Directory of Open Access Journals (Sweden)

    Saurabh Trikha

    2010-01-01

    Full Text Available Essential physiological functions in eukaryotic cells, such as release of hormones and digestive enzymes, neurotransmission, and intercellular signaling, are all achieved by cell secretion. In regulated (calcium-dependent secretion, membrane-bound secretory vesicles dock and transiently fuse with specialized, permanent, plasma membrane structures, called porosomes or fusion pores. Porosomes are supramolecular, cup-shaped lipoprotein structures at the cell plasma membrane that mediate and control the release of vesicle cargo to the outside of the cell. The sizes of porosomes range from 150nm in diameter in acinar cells of the exocrine pancreas to 12nm in neurons. In recent years, significant progress has been made in our understanding of the porosome and the cellular activities required for cell secretion, such as membrane fusion and swelling of secretory vesicles. The discovery of the porosome complex and the molecular mechanism of cell secretion are summarized in this article.

  19. Flow field measurements in the cell culture unit

    Science.gov (United States)

    Walker, Stephen; Wilder, Mike; Dimanlig, Arsenio; Jagger, Justin; Searby, Nancy

    2002-01-01

    The cell culture unit (CCU) is being designed to support cell growth for long-duration life science experiments on the International Space Station (ISS). The CCU is a perfused loop system that provides a fluid environment for controlled cell growth experiments within cell specimen chambers (CSCs), and is intended to accommodate diverse cell specimen types. Many of the functional requirements depend on the fluid flow field within the CSC (e.g., feeding and gas management). A design goal of the CCU is to match, within experimental limits, all environmental conditions, other than the effects of gravity on the cells, whether the hardware is in microgravity ( micro g), normal Earth gravity, or up to 2g on the ISS centrifuge. In order to achieve this goal, two steps are being taken. The first step is to characterize the environmental conditions of current 1g cell biology experiments being performed in laboratories using ground-based hardware. The second step is to ensure that the design of the CCU allows the fluid flow conditions found in 1g to be replicated from microgravity up to 2g. The techniques that are being used to take these steps include flow visualization, particle image velocimetry (PIV), and computational fluid dynamics (CFD). Flow visualization using the injection of dye has been used to gain a global perspective of the characteristics of the CSC flow field. To characterize laboratory cell culture conditions, PIV is being used to determine the flow field parameters of cell suspension cultures grown in Erlenmeyer flasks on orbital shakers. These measured parameters will be compared to PIV measurements in the CSCs to ensure that the flow field that cells encounter in CSCs is within the bounds determined for typical laboratory experiments. Using CFD, a detailed simulation is being developed to predict the flow field within the CSC for a wide variety of flow conditions, including microgravity environments. Results from all these measurements and analyses of the

  20. Failure mechanisms of additively manufactured porous biomaterials: Effects of porosity and type of unit cell.

    Science.gov (United States)

    Kadkhodapour, J; Montazerian, H; Darabi, A Ch; Anaraki, A P; Ahmadi, S M; Zadpoor, A A; Schmauder, S

    2015-10-01

    Since the advent of additive manufacturing techniques, regular porous biomaterials have emerged as promising candidates for tissue engineering scaffolds owing to their controllable pore architecture and feasibility in producing scaffolds from a variety of biomaterials. The architecture of scaffolds could be designed to achieve similar mechanical properties as in the host bone tissue, thereby avoiding issues such as stress shielding in bone replacement procedure. In this paper, the deformation and failure mechanisms of porous titanium (Ti6Al4V) biomaterials manufactured by selective laser melting from two different types of repeating unit cells, namely cubic and diamond lattice structures, with four different porosities are studied. The mechanical behavior of the above-mentioned porous biomaterials was studied using finite element models. The computational results were compared with the experimental findings from a previous study of ours. The Johnson-Cook plasticity and damage model was implemented in the finite element models to simulate the failure of the additively manufactured scaffolds under compression. The computationally predicted stress-strain curves were compared with the experimental ones. The computational models incorporating the Johnson-Cook damage model could predict the plateau stress and maximum stress at the first peak with less than 18% error. Moreover, the computationally predicted deformation modes were in good agreement with the results of scaling law analysis. A layer-by-layer failure mechanism was found for the stretch-dominated structures, i.e. structures made from the cubic unit cell, while the failure of the bending-dominated structures, i.e. structures made from the diamond unit cells, was accompanied by the shearing bands of 45°.

  1. The Croonian lecture 2006. Structure of the living cell.

    Science.gov (United States)

    Campbell, Iain D

    2008-07-27

    The smallest viable unit of life is a single cell. To understand life, we need to visualize the structure of the cell as well as all cellular components and their complexes. This is a formidable task that requires sophisticated tools. These have developed from the rudimentary early microscopes of 350 years ago to a toolbox that includes electron microscopes, synchrotrons, high magnetic fields and vast computing power. This lecture briefly reviews the development of biophysical tools and illustrates how they begin to unravel the 'molecular logic of the living state'.

  2. Stress analysis for wall structure in mobile hot cell design

    Energy Technology Data Exchange (ETDEWEB)

    Bahrin, Muhammad Hannan, E-mail: hannan@nuclearmalaysia.gov.my; Rahman, Anwar Abdul, E-mail: anwar@nuclearmalaysia.gov.my; Hamzah, Mohd Arif, E-mail: arif@nuclearmalaysia.gov.my; Mamat, Mohd Rizal; Azman, Azraf; Hasan, Hasni [Prototype and Plant Development Centre, Technical Services Division, Malaysian Nuclear Agency (Malaysia)

    2016-01-22

    Malaysian Nuclear Agency is developing a Mobile Hot Cell (MHC) in order to handle and manage Spent High Activity Radioactive Sources (SHARS) such as teletherapy heads and irradiators. At present, there are only two units of MHC in the world, in South Africa and China. Malaysian Mobile Hot cell is developed by Malaysian Nuclear Agency with the assistance of IAEA expert, based on the design of South Africa and China, but with improved features. Stress analysis has been performed on the design in order to fulfil the safety requirement in operation of MHC. This paper discusses the loading analysis effect from the sand to the MHC wall structure.

  3. A formalism for scattering of complex composite structures. I. Applications to branched structures of asymmetric sub-units.

    Science.gov (United States)

    Svaneborg, Carsten; Pedersen, Jan Skov

    2012-03-14

    We present a formalism for the scattering of an arbitrary linear or acyclic branched structure build by joining mutually non-interacting arbitrary functional sub-units. The formalism consists of three equations expressing the structural scattering in terms of three equations expressing the sub-unit scattering. The structural scattering expressions allow composite structures to be used as sub-units within the formalism itself. This allows the scattering expressions for complex hierarchical structures to be derived with great ease. The formalism is generic in the sense that the scattering due to structural connectivity is completely decoupled from internal structure of the sub-units. This allows sub-units to be replaced by more complex structures. We illustrate the physical interpretation of the formalism diagrammatically. By applying a self-consistency requirement, we derive the pair distributions of an ideal flexible polymer sub-unit. We illustrate the formalism by deriving generic scattering expressions for branched structures such as stars, pom-poms, bottle-brushes, and dendrimers build out of asymmetric two-functional sub-units.

  4. Additively Manufactured Open-Cell Porous Biomaterials Made from Six Different Space-Filling Unit Cells: The Mechanical and Morphological Properties

    Directory of Open Access Journals (Sweden)

    Seyed Mohammad Ahmadi

    2015-04-01

    Full Text Available It is known that the mechanical properties of bone-mimicking porous biomaterials are a function of the morphological properties of the porous structure, including the configuration and size of the repeating unit cell from which they are made. However, the literature on this topic is limited, primarily because of the challenge in fabricating porous biomaterials with arbitrarily complex morphological designs. In the present work, we studied the relationship between relative density (RD of porous Ti6Al4V EFI alloy and five compressive properties of the material, namely elastic gradient or modulus (Es20–70, first maximum stress, plateau stress, yield stress, and energy absorption. Porous structures with different RD and six different unit cell configurations (cubic (C, diamond (D, truncated cube (TC, truncated cuboctahedron (TCO, rhombic dodecahedron (RD, and rhombicuboctahedron (RCO were fabricated using selective laser melting. Each of the compressive properties increased with increase in RD, the relationship being of a power law type. Clear trends were seen in the influence of unit cell configuration and porosity on each of the compressive properties. For example, in terms of Es20–70, the structures may be divided into two groups: those that are stiff (comprising those made using C, TC, TCO, and RCO unit cell and those that are compliant (comprising those made using D and RD unit cell.

  5. Debris Control at Hydraulic Structures in Selected Areas of the United States and Europe

    Science.gov (United States)

    2007-11-02

    Selected Areas of the United States and Europe by N. Wallerstein , C. R. Thome, University of Nottingham S. R. Abt, Colorado State University Approved...December 1997 Debris Control at Hydraulic Structures in Selected Areas of the United States and Europe by N. Wallerstein , C. R. Thome Department... Wallerstein , N. Debris control at hydraulic structures in selected areas of the United States and Europe / by N. Wallerstein , C.R. Thome, S.R. Abt

  6. Multilayer solar cell waveguide structures containing metamaterials

    Science.gov (United States)

    Hamouche, Houria.; Shabat, Mohammed. M.; Schaadt, Daniel M.

    2017-01-01

    Multilayer antireflection coating structures made from silicon and metamaterials are designed and investigated using the Transfer Matrix Method (TMM). The Transfer Matrix Method is a very useful algorithm for the analysis of periodic structures. We investigate in this paper two anti-reflection coating structures for silicon solar cells with a metamaterial film layer. In the first structure, the metamaterial film layer is sandwiched between a semi-infinite glass cover layer and a semi-infinite silicon substrate layer. The second structure consists of a four layers, a pair of metamaterial-dielectric layer with opposite real part of refractive indices, is placed between the two semi-infinite cover and substrate. We have simulated the absorptivity property of the structures for adjustable thicknesses by using MAPLE software. The absorptivity of the structures achieves greater than 80% for incident electromagnetic wave of transverse magnetic (TM) polarization.

  7. Non-primitive rectangular cells for tight-binding electronic structure calculations

    OpenAIRE

    Boykin, Timothy; Kharche, Neerav; Klimeck, Gerhard

    2009-01-01

    Rectangular non-primitive unit cells are computationally convenient for use in nanodevice electronic structure and transport calculations. When these cells are used for Calculations of structures with periodicity, the resulting bands are zone-folded and must be unfolded in order to identify important gaps and masses. Before the zone-unfolding method can be applied, one must first determine the allowed wavevectors for the specific non-primitive cell. Because most computationally convenient non...

  8. Non-Primitive Rectangular Cells for Tight-Binding Electronic Structure Calculations

    OpenAIRE

    Boykin, Timothy B.

    2008-01-01

    Rectangular non-primitive unit cells are computationally convenient for use in nanodevice electronic structure and transport calculations. When these cells are used for calculations of structures with periodicity, the resulting bands are zone-folded and must be unfolded in order to identify important gaps and masses. Before the zone-unfolding method can be applied, one must first determine the allowed wavevectors for the specific non-primitive cell. Because most computationally convenient ...

  9. Decentralized University Budgeting, United with a More Flexible Tuition Structure

    Science.gov (United States)

    Fethke, Gary

    2014-01-01

    With tuition revenues replacing state appropriations as the primary source of public university funding, it becomes difficult for universities to use historically based budget allocations and inflexible tuition structures to subsidize high-cost programs. It is argued here that combining targeted subsidies with a flexible tuition structure and…

  10. Electronic structure calculations of ESR parameters of melanin units.

    Science.gov (United States)

    Batagin-Neto, Augusto; Bronze-Uhle, Erika Soares; Graeff, Carlos Frederico de Oliveira

    2015-03-21

    Melanins represent an important class of natural pigments present in plants and animals that are currently considered to be promising materials for applications in optic and electronic devices. Despite their interesting properties, some of the basic features of melanins are not satisfactorily understood, including the origin of their intrinsic paramagnetism. A number of experiments have been performed to investigate the electron spin resonance (ESR) response of melanin derivatives, but until now, there has been no consensus regarding the real structure of the paramagnetic centers involved. In this work, we have employed electronic structure calculations to evaluate the ESR parameters of distinct melanin monomers and dimers in order to identify the possible structures associated with unpaired spins in this biopolymer. The g-factors and hyperfine constants of the cationic, anionic and radicalar structures were investigated. The results confirm the existence of at least two distinct paramagnetic centers in melanin structure, identifying the chemical species associated with them and their roles in electrical conductivity.

  11. Additively Manufactured Open-Cell Porous Biomaterials Made from Six Different Space-Filling Unit Cells: The Mechanical and Morphological Properties

    NARCIS (Netherlands)

    Ahmadi, S.M.; Yavari, S.A.; Wauthle, R.; Pouran, B.; Schrooten, J.; Weinans, H.; Zadpoor, A.A.

    2015-01-01

    It is known that the mechanical properties of bone-mimicking porous biomaterials are a function of the morphological properties of the porous structure, including the configuration and size of the repeating unit cell from which they are made. However, the literature on this topic is limited, primari

  12. Protein sectors: evolutionary units of three-dimensional structure

    Science.gov (United States)

    Halabi, Najeeb; Rivoire, Olivier; Leibler, Stanislas; Ranganathan, Rama

    2011-01-01

    Proteins display a hierarchy of structural features at primary, secondary, tertiary, and higher-order levels, an organization that guides our current understanding of their biological properties and evolutionary origins. Here, we reveal a structural organization distinct from this traditional hierarchy by statistical analysis of correlated evolution between amino acids. Applied to the S1A serine proteases, the analysis indicates a decomposition of the protein into three quasi-independent groups of correlated amino acids that we term “protein sectors”. Each sector is physically connected in the tertiary structure, has a distinct functional role, and constitutes an independent mode of sequence divergence in the protein family. Functionally relevant sectors are evident in other protein families as well, suggesting that they may be general features of proteins. We propose that sectors represent a structural organization of proteins that reflects their evolutionary histories. PMID:19703402

  13. Structural, compositional, and sensorial properties of United States commercial ice cream products.

    Science.gov (United States)

    Warren, Maya M; Hartel, Richard W

    2014-10-01

    Commercial vanilla ice cream products from the United States (full fat, low fat, and nonfat) were analyzed for their structural, behavioral (i.e., melt rate and drip-through), compositional, and sensorial attributes. Mean size distributions of ice crystals and air cells, drip-through rates, percent partially coalesced fat, percent overrun and total fat, and density were determined. A trained panel carried out sensory analyses in order to determine correlations between ice cream microstructure attributes and sensory properties using a Spectrum(TM) descriptive analysis. Analyses included melt rate, breakdown, size of ice particulates (iciness), denseness, greasiness, and overall creaminess. To determine relationships and interactions, principle component analysis and multivariate pairwise correlation were performed within and between the instrumental and sensorial data. Greasiness and creaminess negatively correlated with drip-through rate and creaminess correlated with percent total fat and percent fat destabilization. Percent fat did not determine the melt rate on a sensorial level. However, drip-through rate at ambient temperatures was predicted by total fat content of the samples. Based on sensory analysis, high-fat products were noted to be creamier than low and nonfat products. Iciness did not correlate with mean ice crystal size and drip-through rate did not predict sensory melt rate. Furthermore, on a sensorial level, greasiness positively correlated with total percent fat destabilization and mean air cell size positively correlated with denseness. These results indicate that commercial ice cream products vary widely in composition, structure, behavior, and sensory properties. There is a wide range of commercial ice creams in the United States market, ranging from full fat to nonfat. In this research we showed that these ice creams vary greatly in their microstructures, behaviors (the melt/drip-though, collapse, and/or stand up properties of ice cream

  14. Effect of Yttria Content on the Zirconia Unit Cell Parameters

    Energy Technology Data Exchange (ETDEWEB)

    Krogstad, Jessica A.; Lepple, Maren; Gao, Yan; Lipkin, Don M.; Levi, Carlos G. (UCSB); (GE Global)

    2012-02-06

    The relationship between yttria concentration and the unit cell parameters in partially and fully stabilized zirconia has been reassessed, motivated by the need to improve the accuracy of phase analysis upon decomposition of t{prime}-based thermal barrier coatings. Compositions ranging from 6 to 18 mol% YO{sub 1.5} were synthesized and examined by means of high-resolution X-ray diffraction. Lattice parameters were determined using the Rietveld refinement method, a whole-pattern fitting procedure. The revised empirical relationships fall within the range of those published previously. However, efforts to achieve superior homogeneity of the materials, as well as accuracy of the composition and lattice parameters, provide increased confidence in the reliability of these correlations for use in future studies. Additional insight into the potential sources for scatter previously reported for the transition region ({approx}12-14 mol% YO{sub 1.5}), where tetragonal and cubic phases have been observed to coexist, is also provided. Implications on the current understanding of stabilization mechanisms in zirconia are discussed.

  15. Characterization of relationships between transcriptional units and operon structures in Bacillus subtilis and Escherichia coli

    Directory of Open Access Journals (Sweden)

    Kanehisa Minoru

    2007-02-01

    Full Text Available Abstract Background Operon structures play an important role in transcriptional regulation in prokaryotes. However, there have been fewer studies on complicated operon structures in which the transcriptional units vary with changing environmental conditions. Information about such complicated operons is helpful for predicting and analyzing operon structures, as well as understanding gene functions and transcriptional regulation. Results We systematically analyzed the experimentally verified transcriptional units (TUs in Bacillus subtilis and Escherichia coli obtained from ODB and RegulonDB. To understand the relationships between TUs and operons, we defined a new classification system for adjacent gene pairs, divided into three groups according to the level of gene co-regulation: operon pairs (OP belong to the same TU, sub-operon pairs (SOP that are at the transcriptional boundaries within an operon, and non-operon pairs (NOP belonging to different operons. Consequently, we found that the levels of gene co-regulation was correlated to intergenic distances and gene expression levels. Additional analysis revealed that they were also correlated to the levels of conservation across about 200 prokaryotic genomes. Most interestingly, we found that functional associations in SOPs were more observed in the environmental and genetic information processes. Conclusion Complicated operon strucutures were correlated with genome organization and gene expression profiles. Such intricately regulated operons allow functional differences depending on environmental conditions. These regulatory mechanisms are helpful in accommodating the variety of changes that happen around the cell. In addition, such differences may play an important role in the evolution of gene order across genomes.

  16. Challenges in structural approaches to cell modeling.

    Science.gov (United States)

    Im, Wonpil; Liang, Jie; Olson, Arthur; Zhou, Huan-Xiang; Vajda, Sandor; Vakser, Ilya A

    2016-07-31

    Computational modeling is essential for structural characterization of biomolecular mechanisms across the broad spectrum of scales. Adequate understanding of biomolecular mechanisms inherently involves our ability to model them. Structural modeling of individual biomolecules and their interactions has been rapidly progressing. However, in terms of the broader picture, the focus is shifting toward larger systems, up to the level of a cell. Such modeling involves a more dynamic and realistic representation of the interactomes in vivo, in a crowded cellular environment, as well as membranes and membrane proteins, and other cellular components. Structural modeling of a cell complements computational approaches to cellular mechanisms based on differential equations, graph models, and other techniques to model biological networks, imaging data, etc. Structural modeling along with other computational and experimental approaches will provide a fundamental understanding of life at the molecular level and lead to important applications to biology and medicine. A cross section of diverse approaches presented in this review illustrates the developing shift from the structural modeling of individual molecules to that of cell biology. Studies in several related areas are covered: biological networks; automated construction of three-dimensional cell models using experimental data; modeling of protein complexes; prediction of non-specific and transient protein interactions; thermodynamic and kinetic effects of crowding; cellular membrane modeling; and modeling of chromosomes. The review presents an expert opinion on the current state-of-the-art in these various aspects of structural modeling in cellular biology, and the prospects of future developments in this emerging field. Copyright © 2016 Elsevier Ltd. All rights reserved.

  17. Numerological Phraseological Units in Multi-structural Languages

    Directory of Open Access Journals (Sweden)

    Rauan Dossymbekova

    2016-11-01

    Full Text Available This paper is devoted to the comparative-semantic analysis of numerological phraseological units (PU in the unrelated languages, namely, Kazakh and English. The identification of the similarities and differences of fixed collocations of multiple languages is a spread type of comparative analysis in phraseology. The possibility of verbalization of the natural environment and man-made environment of ethnic group becomes apparent in comparative studies and description of any lexical-semantic groups of two or more languages. In our work we consider lexical-semantic group of numbers category in Kazakh and English. Numerals are actively involved in the formation of PU, thereby forming a large reservoir of numerological PU and deserve a special consideration. The work is ethnolinguistic and linguoculturological description of the main vernacular numerals, included in the set phrases of the languages. Main methods of the research are: method of semantic analysis, descriptive method, comparative analysis, method of sampling.

  18. The effect of family structure on parents' child care time in the United States and the United Kingdom

    OpenAIRE

    Kalenkoski, Charlene Marie; Ribar, David C.; Stratton, Leslie Sundt

    2006-01-01

    We use time-diary data from the 2003 and 2004 American Time Use Surveys and the 2000 United Kingdom Time Use Study to estimate the effect of family structure on the time mothers and fathers spend on primary and passive child care and on market work, using a system of correlated Tobit equations and family structure equations. Estimates from these models indicate that single parents in both countries spend more time in child care than married or cohabiting parents. There are differences, howeve...

  19. A Structured Population Model of Cell Differentiation

    CERN Document Server

    Doumic, Marie; Perthame, Benoit; Zubelli, Jorge P

    2010-01-01

    We introduce and analyze several aspects of a new model for cell differentiation. It assumes that differentiation of progenitor cells is a continuous process. From the mathematical point of view, it is based on partial differential equations of transport type. Specifically, it consists of a structured population equation with a nonlinear feedback loop. This models the signaling process due to cytokines, which regulate the differentiation and proliferation process. We compare the continuous model to its discrete counterpart, a multi-compartmental model of a discrete collection of cell subpopulations recently proposed by Marciniak-Czochra et al. in 2009 to investigate the dynamics of the hematopoietic system. We obtain uniform bounds for the solutions, characterize steady state solutions, and analyze their linearized stability. We show how persistence or extinction might occur according to values of parameters that characterize the stem cells self-renewal. We also perform numerical simulations and discuss the q...

  20. Single fibre and multifibre unit cell analysis of strength and cracking of unidirectional composites

    DEFF Research Database (Denmark)

    Wang, H.W.; Zhou, H.W.; Mishnaevsky, Leon

    2009-01-01

    Numerical simulations of damage evolution in composites reinforced with single and multifibre are presented. Several types of unit cell models are considered: single fibre unit cell, multiple fibre unit cell with one and several damageable sections per fibres, unit cells with homogeneous...... damageable parts in composites (matrix cracks, fibre/matrix interface damage and fibre fracture) was observed in the simulations. The strength of interface begins to influence the deformation behaviour of the cell only after the fibre is broken. In this case, the higher interface layer strength leads...... and inhomogeneous interfaces, etc. Two numerical damage models, cohesive elements, and damageable layers are employed for the simulation of the damage evolution in single fibre and multifibre unit cells. The two modelling approaches were compared and lead to the very close results. Competition among the different...

  1. Root cause analysis of the degradation in a unitized regenerative fuel cell

    Science.gov (United States)

    Bhosale, Amit C.; Meenakshi, S.; Ghosh, Prakash C.

    2017-03-01

    The present study emphasizes the possible modes of failure of a unitized regenerative fuel cell (URFC) when operated in fuel cell as well as in electrolysis mode at different temperatures viz. 30 °C and 60 °C. The carbon based catalyst (Pt/C) and diffusion layers are used to characterize the degradation of the URFCs. The electrolysis mode of operation is found to dominate the root cause of failure with increase in temperature. Agglomeration and loss of catalyst along with delamination of electrode from membrane are observed. Membrane degradation owing to it's structural as well as chemical damage is seen to be prominent at higher temperature. Characterization techniques such as SEM, TEM and ICP-AES confirm the study showcasing the effect.

  2. Optimizing energy management of decentralized photovoltaic. Fuel cell - direct storage - power supply units

    Energy Technology Data Exchange (ETDEWEB)

    Bocklisch, Thilo; Schufft, Wolfgang; Bocklisch, Steffen [Chemnitz Univ. of Technology (TUC) (Germany)

    2010-07-01

    This paper presents a new optimizing energy management concept for decentralized power supply units. Main goal is the coordinated utilization of dynamically controllable combined-heat-and-power-plants (e.g. fuel cell cogeneration plants) and electrochemical direct storages (e.g. future electric car batteries) for the active balancing of fluctuating renewable energy generation (e.g. building integrated photovoltaics) and fluctuation electricity consumption. The self-utilization and partial storage of renewable energy helps to stabilize the grid in a ''bottom-up'' approach. The new energy mangement concept features a three-layer control structure, which aims for the optimization of the power flows, minimizing the fuel consumption and the dynamic stress imposed onto the fuel cell. (orig.)

  3. Thickness of the middle Fort Union hydrogeologic unit in the Williston structural basin

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — These data represent the thickness, in feet, of the middle Fort Union hydrogeologic unit in the Williston structural basin. The data are presented as ASCII text...

  4. Thickness of the Upper Hell Creek hydrogeologic unit in the Williston structural basin

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — These data represent the thickness, in feet, of the Upper Hell Creek hydrogeologic unit in the Williston structural basin. The data are presented as ASCII text...

  5. The Interaction of the Logistics System with the Structural Units of the Company

    Directory of Open Access Journals (Sweden)

    Aleksey Shapovalov

    2012-12-01

    Full Text Available The article detects major flows that occur in business activities of any business entity. The examined flows describe the interaction of the logistic system with the structural units of the company.

  6. Tunable Multifunctional Thermal Metamaterials: Manipulation of Local Heat Flux via Assembly of Unit-Cell Thermal Shifters.

    Science.gov (United States)

    Park, Gwanwoo; Kang, Sunggu; Lee, Howon; Choi, Wonjoon

    2017-01-20

    Thermal metamaterials, designed by transformation thermodynamics are artificial structures that can actively control heat flux at a continuum scale. However, fabrication of them is very challenging because it requires a continuous change of thermal properties in materials, for one specific function. Herein, we introduce tunable thermal metamaterials that use the assembly of unit-cell thermal shifters for a remarkable enhancement in multifunctionality as well as manufacturability. Similar to the digitization of a two-dimensional image, designed thermal metamaterials by transformation thermodynamics are disassembled as unit-cells thermal shifters in tiny areas, representing discretized heat flux lines in local spots. The programmed-reassembly of thermal shifters inspired by LEGO enable the four significant functions of thermal metamaterials-shield, concentrator, diffuser, and rotator-in both simulation and experimental verification using finite element method and fabricated structures made from copper and PDMS. This work paves the way for overcoming the structural and functional limitations of thermal metamaterials.

  7. Tunable Multifunctional Thermal Metamaterials: Manipulation of Local Heat Flux via Assembly of Unit-Cell Thermal Shifters

    Science.gov (United States)

    Park, Gwanwoo; Kang, Sunggu; Lee, Howon; Choi, Wonjoon

    2017-01-01

    Thermal metamaterials, designed by transformation thermodynamics are artificial structures that can actively control heat flux at a continuum scale. However, fabrication of them is very challenging because it requires a continuous change of thermal properties in materials, for one specific function. Herein, we introduce tunable thermal metamaterials that use the assembly of unit-cell thermal shifters for a remarkable enhancement in multifunctionality as well as manufacturability. Similar to the digitization of a two-dimensional image, designed thermal metamaterials by transformation thermodynamics are disassembled as unit-cells thermal shifters in tiny areas, representing discretized heat flux lines in local spots. The programmed-reassembly of thermal shifters inspired by LEGO enable the four significant functions of thermal metamaterials—shield, concentrator, diffuser, and rotator—in both simulation and experimental verification using finite element method and fabricated structures made from copper and PDMS. This work paves the way for overcoming the structural and functional limitations of thermal metamaterials. PMID:28106156

  8. Exfoliation of natural van der Waals heterostructures to a single unit cell thickness

    Science.gov (United States)

    Velický, Matěj; Toth, Peter S.; Rakowski, Alexander M.; Rooney, Aidan P.; Kozikov, Aleksey; Woods, Colin R.; Mishchenko, Artem; Fumagalli, Laura; Yin, Jun; Zólyomi, Viktor; Georgiou, Thanasis; Haigh, Sarah J.; Novoselov, Kostya S.; Dryfe, Robert A. W.

    2017-02-01

    Weak interlayer interactions in van der Waals crystals facilitate their mechanical exfoliation to monolayer and few-layer two-dimensional materials, which often exhibit striking physical phenomena absent in their bulk form. Here we utilize mechanical exfoliation to produce a two-dimensional form of a mineral franckeite and show that the phase segregation of chemical species into discrete layers at the sub-nanometre scale facilitates franckeite's layered structure and basal cleavage down to a single unit cell thickness. This behaviour is likely to be common in a wider family of complex minerals and could be exploited for a single-step synthesis of van der Waals heterostructures, as an alternative to artificial stacking of individual two-dimensional crystals. We demonstrate p-type electrical conductivity and remarkable electrochemical properties of the exfoliated crystals, showing promise for a range of applications, and use the density functional theory calculations of franckeite's electronic band structure to rationalize the experimental results.

  9. Automated assembling of single fuel cell units for use in a fuel cell stack

    Science.gov (United States)

    Jalba, C. K.; Muminovic, A.; Barz, C.; Nasui, V.

    2017-05-01

    The manufacturing of PEMFC stacks (POLYMER ELEKTROLYT MEMBRAN Fuel Cell) is nowadays still done by hand. Over hundreds of identical single components have to be placed accurate together for the construction of a fuel cell stack. Beside logistic problems, higher total costs and disadvantages in weight the high number of components produce a higher statistic interference because of faulty erection or material defects and summation of manufacturing tolerances. The saving of costs is about 20 - 25 %. Furthermore, the total weight of the fuel cells will be reduced because of a new sealing technology. Overall a one minute cycle time has to be aimed per cell at the manufacturing of these single components. The change of the existing sealing concept to a bonded sealing is one of the important requisites to get an automated manufacturing of single cell units. One of the important steps for an automated gluing process is the checking of the glue application by using of an image processing system. After bonding the single fuel cell the sealing and electrical function can be checked, so that only functional and high qualitative cells can get into further manufacturing processes.

  10. Thermal performance of direct illumination high-power LED backlight units with different assembling structures

    Science.gov (United States)

    Wang, Yiwei; Cen, Jiwen; Cao, Wenjiong; Jiang, Fangming

    2016-10-01

    This work presents a detailed study about the heat dissipation performance of direct illumination high-power light emitting diode (LED) backlight units with two different assembling structures, one of which is traditional and the other is new. The traditional structure, referred to by structure-1, consists of multiple LEDs being directly welded to the printed circuit board (PCB), where the PCB is used as a physical support, an electrical connector and also as a heat dissipation medium. The new structure, referred to by structure-2, places the LEDs directly on the cooling boss; in this case the PCB plays mainly the role of an electrical connector. Thermal characteristics related to the two backlight units are analyzed in terms of thermal resistance network, numerically simulated and experimentally tested. The obtained results by different methods accord with each other reasonably well and all indicate that both structures can meet the requirements of heat dissipation for backlight units at an ambient temperature of 30 °C. Among the two structures, the LED junction temperature of structure-1 backlight unit is 7-8 °C higher and the temperature distribution in the back plane of the backlight unit is also more uniform.

  11. X-ray powder diffraction data and unit cells of ammonium paratungstate tetrahydrate

    NARCIS (Netherlands)

    Put, J.W. van; Verkroost, T.W.; Sonneveld, E.J.

    1990-01-01

    X-Ray powder diffraction data and unit cell parameters of industrially produced, as well as bench scale prepared, ammonium paratungstate tetrahydrate are reported and compared with current Powder Data file (PDF) (1989) patterns. A least-squares refinement resulted in two slightly different unit cell

  12. Bacterial cell surface structures in Yersinia enterocolitica.

    Science.gov (United States)

    Białas, Nataniel; Kasperkiewicz, Katarzyna; Radziejewska-Lebrecht, Joanna; Skurnik, Mikael

    2012-06-01

    Yersinia enterocolitica is a widespread member of the family of Enterobacteriaceae that contains both non-virulent and virulent isolates. Pathogenic Y. enterocolitica strains, especially belonging to serotypes O:3, O:5,27, O:8 and O:9 are etiologic agents of yersiniosis in animals and humans. Y. enterocolitica cell surface structures that play a significant role in virulence have been subject to many investigations. These include outer membrane (OM) glycolipids such as lipopolysaccharide (LPS) and enterobacterial common antigen (ECA) and several cell surface adhesion proteins present only in virulent Y. enterocolitica, i.e., Inv, YadA and Ail. While the yadA gene is located on the Yersinia virulence plasmid the Ail, Inv, LPS and ECA are chromosomally encoded. These structures ensure the correct architecture of the OM, provide adhesive properties as well as resistance to antimicrobial peptides and to host innate immune response mechanisms.

  13. Reaction of sulfur-containing structural units of transition metals

    Institute of Scientific and Technical Information of China (English)

    陈忠宁; 康北笙; 童叶翔; 张华新; 苏成勇; 林璋; 洪茂椿; 郁开北

    1997-01-01

    Two tri-n-butylphosphme-participated ( PBu3n) nickel (Ⅱ) complexes of 2-mercaptophenol(H2mp),i.e,Ni2Ru(mp)3(Hmp)(PBu3n)3 3 exhibiting a curved heterotrinuclear metal skeleton and its mononuclear "synthon",[HNEt3] [Ni(mp) (Hmp) (PBu3n)] 1 were synthesized and characterized by X-crystallography and 1H NMR,FAB-MS and cyclic valtammogram measurements.The nickel(Ⅱ) center in 1 has a square-planar geometry For 3,the ruthenium(Ⅲ) atom is in a distorted octahedral environment and the two mckel(Ⅱ) atoms exhibit square-planar and rare triangle-planar geometries,respectively.The Ni (1)-Ru-Ni(2 ) arrangement is severely asymmetric with the distances 0.254 and 0.394 nm,respectively,for Ni(1)-Ru and Ni(2)-Ru.The structural regularities of relevant complexes are summarized in relation to the structural as well as spectra data.

  14. The APOBEC Protein Family: United by Structure, Divergent in Function.

    Science.gov (United States)

    Salter, Jason D; Bennett, Ryan P; Smith, Harold C

    2016-07-01

    The APOBEC (apolipoprotein B mRNA editing catalytic polypeptide-like) family of proteins have diverse and important functions in human health and disease. These proteins have an intrinsic ability to bind to both RNA and single-stranded (ss) DNA. Both function and tissue-specific expression varies widely for each APOBEC protein. We are beginning to understand that the activity of APOBEC proteins is regulated through genetic alterations, changes in their transcription and mRNA processing, and through their interactions with other macromolecules in the cell. Loss of cellular control of APOBEC activities leads to DNA hypermutation and promiscuous RNA editing associated with the development of cancer or viral drug resistance, underscoring the importance of understanding how APOBEC proteins are regulated.

  15. A 3D bioprinted complex structure for engineering the muscle-tendon unit.

    Science.gov (United States)

    Merceron, Tyler K; Burt, Morgan; Seol, Young-Joon; Kang, Hyun-Wook; Lee, Sang Jin; Yoo, James J; Atala, Anthony

    2015-06-17

    Three-dimensional integrated organ printing (IOP) technology seeks to fabricate tissue constructs that can mimic the structural and functional properties of native tissues. This technology is particularly useful for complex tissues such as those in the musculoskeletal system, which possess regional differences in cell types and mechanical properties. Here, we present the use of our IOP system for the processing and deposition of four different components for the fabrication of a single integrated muscle-tendon unit (MTU) construct. Thermoplastic polyurethane (PU) was co-printed with C2C12 cell-laden hydrogel-based bioink for elasticity and muscle development on one side, while poly(ϵ-caprolactone) (PCL) was co-printed with NIH/3T3 cell-laden hydrogel-based bioink for stiffness and tendon development on the other. The final construct was elastic on the PU-C2C12 muscle side (E = 0.39 ± 0.05 MPa), stiff on the PCL-NIH/3T3 tendon side (E = 46.67 ± 2.67 MPa) and intermediate in the interface region (E = 1.03 ± 0.14 MPa). These constructs exhibited >80% cell viability at 1 and 7 d after printing, as well as initial tissue development and differentiation. This study demonstrates the versatility of the IOP system to create integrated tissue constructs with region-specific biological and mechanical characteristics for MTU engineering.

  16. Parallel Block Structured Adaptive Mesh Refinement on Graphics Processing Units

    Energy Technology Data Exchange (ETDEWEB)

    Beckingsale, D. A. [Atomic Weapons Establishment (AWE), Aldermaston (United Kingdom); Gaudin, W. P. [Atomic Weapons Establishment (AWE), Aldermaston (United Kingdom); Hornung, R. D. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Gunney, B. T. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Gamblin, T. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Herdman, J. A. [Atomic Weapons Establishment (AWE), Aldermaston (United Kingdom); Jarvis, S. A. [Atomic Weapons Establishment (AWE), Aldermaston (United Kingdom)

    2014-11-17

    Block-structured adaptive mesh refinement is a technique that can be used when solving partial differential equations to reduce the number of zones necessary to achieve the required accuracy in areas of interest. These areas (shock fronts, material interfaces, etc.) are recursively covered with finer mesh patches that are grouped into a hierarchy of refinement levels. Despite the potential for large savings in computational requirements and memory usage without a corresponding reduction in accuracy, AMR adds overhead in managing the mesh hierarchy, adding complex communication and data movement requirements to a simulation. In this paper, we describe the design and implementation of a native GPU-based AMR library, including: the classes used to manage data on a mesh patch, the routines used for transferring data between GPUs on different nodes, and the data-parallel operators developed to coarsen and refine mesh data. We validate the performance and accuracy of our implementation using three test problems and two architectures: an eight-node cluster, and over four thousand nodes of Oak Ridge National Laboratory’s Titan supercomputer. Our GPU-based AMR hydrodynamics code performs up to 4.87× faster than the CPU-based implementation, and has been scaled to over four thousand GPUs using a combination of MPI and CUDA.

  17. Map service: United States Decadal Production History Cells

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This map service displays present and past oil and gas production in the United States, as well as the location and intensity of exploratory drilling outside...

  18. Intensive English Programs in the United States: An Overview of Structure and Mentoring

    Science.gov (United States)

    Thompson, Amy S.

    2013-01-01

    Although English as a second language (ESL) programs are common in the United States, there is surprisingly little research documenting the existing structures and mentoring strategies they use. This lack of research could be partly due to ESL programs' widely varying internal structures (Larson, 1990) and the fact that they are often marginalized…

  19. Imaging the impact on cuprate superconductivity of varying the interatomic distances within individual crystal unit cells.

    Science.gov (United States)

    Slezak, J A; Lee, Jinho; Wang, M; McElroy, K; Fujita, K; Andersen, B M; Hirschfeld, P J; Eisaki, H; Uchida, S; Davis, J C

    2008-03-04

    Many theoretical models of high-temperature superconductivity focus only on the doping dependence of the CuO(2)-plane electronic structure. However, such models are manifestly insufficient to explain the strong variations in superconducting critical temperature, T(c), among cuprates that have identical hole density but are crystallographically different outside of the CuO(2) plane. A key challenge, therefore, has been to identify a predominant out-of-plane influence controlling the superconductivity, with much attention focusing on the distance d(A) between the apical oxygen and the planar copper atom. Here we report direct determination of how variations in interatomic distances within individual crystalline unit cells affect the superconducting energy-gap maximum Delta of Bi(2)Sr(2)CaCu(2)O(8+delta). In this material, quasiperiodic variations of unit cell geometry occur in the form of a bulk crystalline "supermodulation." Within each supermodulation period, we find approximately 9 +/- 1% cosinusoidal variation in local Delta that is anticorrelated with the associated d(A) variations. Furthermore, we show that phenomenological consistency would exist between these effects and the random Delta variations found near dopant atoms if the primary effect of the interstitial dopant atom is to displace the apical oxygen so as to diminish d(A) or tilt the CuO(5) pyramid. Thus, we reveal a strong, nonrandom out-of-plane effect on cuprate superconductivity at atomic scale.

  20. Intra-unit-cell nematic charge order in the titanium-oxypnictide family of superconductors

    Science.gov (United States)

    Frandsen, Benjamin A.; Bozin, Emil S.; Hu, Hefei; Zhu, Yimei; Nozaki, Yasumasa; Kageyama, Hiroshi; Uemura, Yasutomo J.; Yin, Wei-Guo; Billinge, Simon J. L.

    2014-12-01

    Understanding the role played by broken-symmetry states such as charge, spin and orbital orders in the mechanism of emergent properties, such as high-temperature superconductivity, is a major current topic in materials research. That the order may be within one unit cell, such as nematic, was only recently considered theoretically, but its observation in the iron-pnictide and doped cuprate superconductors places it at the forefront of current research. Here, we show that the recently discovered BaTi2Sb2O superconductor and its parent compound BaTi2As2O form a symmetry-breaking nematic ground state that can be naturally explained as an intra-unit-cell nematic charge order with d-wave symmetry, pointing to the ubiquity of the phenomenon. These findings, together with the key structural features in these materials being intermediate between the cuprate and iron-pnictide high-temperature superconducting materials, render the titanium oxypnictides an important new material system to understand the nature of nematic order and its relationship to superconductivity.

  1. Structure of the organic crystallite unit in coal as determined by X-ray diffraction

    Institute of Scientific and Technical Information of China (English)

    Song Dangyu; Yang Cunbei; Zhang Xiaokui; Su Xianbo; Zhang Xiaodong

    2011-01-01

    X-ray diffraction (XRD) was used to study the structure of the organic crystallite unit (La,Lc,d002) in coals collected from Henan and Shanxi Provinces,XRD patterns of coal were collected in a step-scan mode (0.1 °/step) over an angular range of 2-90° (2θ),allowing 8 s at each step.The structure of the crystallite unit was determined from the Scherrer equation and peak parameters deduced from whole pattern fitting.The results show that the structure of the crystallite unit in coal is mainly controlled by the coal rank.As the coal rank increases the average diameter of a coal crystallite unit (La) increases,the interlayer spacing (d002) decreases slightly,and the average height of a coal crystallite unit (Lc) increases at first but then decreases.A new diffraction peak from the crystallite unit in coal was found at a low scattering angle in the XRD pattern (2-10°).This suggests a structure with an inter-layer spacing from 1.9 to 2.8 nm exists in coal crystallites.

  2. Direct volume rendering methods for cell structures.

    Science.gov (United States)

    Martišek, Dalibor; Martišek, Karel

    2012-01-01

    The study of the complicated architecture of cell space structures is an important problem in biology and medical research. Optical cuts of cells produced by confocal microscopes enable two-dimensional (2D) and three-dimensional (3D) reconstructions of observed cells. This paper discuses new possibilities for direct volume rendering of these data. We often encounter 16 or more bit images in confocal microscopy of cells. Most of the information contained in these images is unsubstantial for the human vision. Therefore, it is necessary to use mathematical algorithms for visualization of such images. Present software tools as OpenGL or DirectX run quickly in graphic station with special graphic cards, run very unsatisfactory on PC without these cards and outputs are usually poor for real data. These tools are black boxes for a common user and make it impossible to correct and improve them. With the method proposed, more parameters of the environment can be set, making it possible to apply 3D filters to set the output image sharpness in relation to the noise. The quality of the output is incomparable to the earlier described methods and is worth increasing the computing time. We would like to offer mathematical methods of 3D scalar data visualization describing new algorithms that run on standard PCs very well.

  3. Structural correlates of rotavirus cell entry.

    Directory of Open Access Journals (Sweden)

    Aliaa H Abdelhakim

    2014-09-01

    Full Text Available Cell entry by non-enveloped viruses requires translocation into the cytosol of a macromolecular complex--for double-strand RNA viruses, a complete subviral particle. We have used live-cell fluorescence imaging to follow rotavirus entry and penetration into the cytosol of its ∼ 700 Å inner capsid particle ("double-layered particle", DLP. We label with distinct fluorescent tags the DLP and each of the two outer-layer proteins and track the fates of each species as the particles bind and enter BSC-1 cells. Virions attach to their glycolipid receptors in the host cell membrane and rapidly become inaccessible to externally added agents; most particles that release their DLP into the cytosol have done so by ∼ 10 minutes, as detected by rapid diffusional motion of the DLP away from residual outer-layer proteins. Electron microscopy shows images of particles at various stages of engulfment into tightly fitting membrane invaginations, consistent with the interpretation that rotavirus particles drive their own uptake. Electron cryotomography of membrane-bound virions also shows closely wrapped membrane. Combined with high resolution structural information about the viral components, these observations suggest a molecular model for membrane disruption and DLP penetration.

  4. [Structure and function of fungal cell wall].

    Science.gov (United States)

    Ohno, Naohito

    2008-12-01

    Cell wall glycans of fungi/yeasts are reviewed. Fungi/yeasts produce various kinds of polysaccharides. As part of the cell wall they are interlinked with other components forming a huge network. The insolubility and complex with multiple components makes the research very tough. Studies on beta-glucan have been performed from various views, such as chemistry, conformation, solubility, tissue distribution and metabolism, biological activity, clinical application, receptor, biosynthesis, and antibody. Studies on mannan focus on immunotoxicity, such as anaphylactoid reaction and coronary arteritis induction. alpha-glucan, chitin, and capsular polysaccharide were also mentioned in relation to structure and genes. Compared with human and animal polysaccharides, fungi/yeasts polysaccharides have very characteristic properties.

  5. Hydrogen Fuel Cell Performance as Telecommunications Backup Power in the United States

    Energy Technology Data Exchange (ETDEWEB)

    Kurtz, Jennifer [National Renewable Energy Lab. (NREL), Golden, CO (United States); Saur, Genevieve [National Renewable Energy Lab. (NREL), Golden, CO (United States); Sprik, Sam [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2015-03-01

    Working in collaboration with the U.S. Department of Energy (DOE) and industry project partners, the National Renewable Energy Laboratory (NREL) acts as the central data repository for the data collected from real-world operation of fuel cell backup power systems. With American Recovery and Reinvestment Act of 2009 (ARRA) co-funding awarded through DOE's Fuel Cell Technologies Office, more than 1,300 fuel cell units were deployed over a three-plus-year period in stationary, material handling equipment, auxiliary power, and backup power applications. This surpassed a Fuel Cell Technologies Office ARRA objective to spur commercialization of an early market technology by installing 1,000 fuel cell units across several different applications, including backup power. By December 2013, 852 backup power units out of 1,330 fuel cell units deployed were providing backup service, mainly for telecommunications towers. For 136 of the fuel cell backup units, project participants provided detailed operational data to the National Fuel Cell Technology Evaluation Center for analysis by NREL's technology validation team. NREL analyzed operational data collected from these government co-funded demonstration projects to characterize key fuel cell backup power performance metrics, including reliability and operation trends, and to highlight the business case for using fuel cells in these early market applications. NREL's analyses include these critical metrics, along with deployment, U.S. grid outage statistics, and infrastructure operation.

  6. Single-cell Hi-C reveals cell-to-cell variability in chromosome structure.

    Science.gov (United States)

    Nagano, Takashi; Lubling, Yaniv; Stevens, Tim J; Schoenfelder, Stefan; Yaffe, Eitan; Dean, Wendy; Laue, Ernest D; Tanay, Amos; Fraser, Peter

    2013-10-03

    Large-scale chromosome structure and spatial nuclear arrangement have been linked to control of gene expression and DNA replication and repair. Genomic techniques based on chromosome conformation capture (3C) assess contacts for millions of loci simultaneously, but do so by averaging chromosome conformations from millions of nuclei. Here we introduce single-cell Hi-C, combined with genome-wide statistical analysis and structural modelling of single-copy X chromosomes, to show that individual chromosomes maintain domain organization at the megabase scale, but show variable cell-to-cell chromosome structures at larger scales. Despite this structural stochasticity, localization of active gene domains to boundaries of chromosome territories is a hallmark of chromosomal conformation. Single-cell Hi-C data bridge current gaps between genomics and microscopy studies of chromosomes, demonstrating how modular organization underlies dynamic chromosome structure, and how this structure is probabilistically linked with genome activity patterns.

  7. Single cell Hi-C reveals cell-to-cell variability in chromosome structure

    Science.gov (United States)

    Schoenfelder, Stefan; Yaffe, Eitan; Dean, Wendy; Laue, Ernest D.; Tanay, Amos; Fraser, Peter

    2013-01-01

    Large-scale chromosome structure and spatial nuclear arrangement have been linked to control of gene expression and DNA replication and repair. Genomic techniques based on chromosome conformation capture assess contacts for millions of loci simultaneously, but do so by averaging chromosome conformations from millions of nuclei. Here we introduce single cell Hi-C, combined with genome-wide statistical analysis and structural modeling of single copy X chromosomes, to show that individual chromosomes maintain domain organisation at the megabase scale, but show variable cell-to-cell chromosome territory structures at larger scales. Despite this structural stochasticity, localisation of active gene domains to boundaries of territories is a hallmark of chromosomal conformation. Single cell Hi-C data bridge current gaps between genomics and microscopy studies of chromosomes, demonstrating how modular organisation underlies dynamic chromosome structure, and how this structure is probabilistically linked with genome activity patterns. PMID:24067610

  8. Structural determination of Streptococcus pneumoniae repeat units in serotype 41A and 41F capsular polysaccharides to probe gene functions in the corresponding capsular biosynthetic loci

    DEFF Research Database (Denmark)

    Petersen, Bent O.; Skovsted, Ian C.; Paulsen, Berit Smestad

    2014-01-01

    We report the repeating unit structures ofthe native capsular polysaccharidesof S. pneumoniaeserotypes 41A and 41F. Structuraldeterminationsyieldedsix carbohydrate units in the doubly branched repeating unit to givethe following structure for serotype 41A:The structure determinations were motivat...

  9. An explicit algorithm for fully flexible unit cell simulation with recursive thermostat chains.

    Science.gov (United States)

    Jung, Kwangsub; Cho, Maenghyo

    2008-10-28

    Through the combination of the recursive multiple thermostat (RMT) Nose-Poincare and Parrinello-Rahman methods, the recursive multiple thermostat chained fully flexible unit cell (RMT-NsigmaT) molecular dynamics method is proposed for isothermal-isobaric simulation. The RMT method is known to have the advantage of achieving the ergodicity that is required for canonical sampling of the harmonic oscillator. Thus, an explicit time integration algorithm is developed for RMT-NsigmaT. We examine the ergodicity for various parameters of RMT-NsigmaT using bulk and thin film structures with different numbers of copper atoms and thicknesses in various environments. Through the numerical simulations, we conclude that the RMT-NsigmaT method is advantageous in the cases of lower temperatures.

  10. Unit roots and structural breakpoints in China's macroeconomic and financial time series

    Institute of Scientific and Technical Information of China (English)

    LIANG Qi; TENG Jianzhou

    2006-01-01

    This paper applies unit-root tests to 10 Chinese macroeconomic and financial time series that allow for the possibility of up to two endogenous structural breaks.We found that 6 of the series,i.e.,GDP,GDP per capita,employment,bank credit,deposit liabilities and investment,can be more accurately characterized as a segmented trend stationarity process around one or two structural breakpoints as opposed to a stochastic unit root process.Our findings have important implications for policy-makers to formulate long-term growth strategy and short-run stabilization policies,as well as causality analysis among the series.

  11. The Vertebrate Brain, Evidence of Its Modular Organization and Operating System: Insights into the Brain's Basic Units of Structure, Function, and Operation and How They Influence Neuronal Signaling and Behavior.

    Science.gov (United States)

    Baslow, Morris H

    2011-01-01

    The human brain is a complex organ made up of neurons and several other cell types, and whose role is processing information for use in eliciting behaviors. However, the composition of its repeating cellular units for both structure and function are unresolved. Based on recent descriptions of the brain's physiological "operating system", a function of the tri-cellular metabolism of N-acetylaspartate (NAA) and N-acetylaspartylglutamate (NAAG) for supply of energy, and on the nature of "neuronal words and languages" for intercellular communication, insights into the brain's modular structural and functional units have been gained. In this article, it is proposed that the basic structural unit in brain is defined by its physiological operating system, and that it consists of a single neuron, and one or more astrocytes, oligodendrocytes, and vascular system endothelial cells. It is also proposed that the basic functional unit in the brain is defined by how neurons communicate, and consists of two neurons and their interconnecting dendritic-synaptic-dendritic field. Since a functional unit is composed of two neurons, it requires two structural units to form a functional unit. Thus, the brain can be envisioned as being made up of the three-dimensional stacking and intertwining of myriad structural units which results not only in its gross structure, but also in producing a uniform distribution of binary functional units. Since the physiological NAA-NAAG operating system for supply of energy is repeated in every structural unit, it is positioned to control global brain function.

  12. Fluorescence-Activated Cell Sorting Analysis of Heterotypic Cell-in-Cell Structures.

    Science.gov (United States)

    He, Meifang; Huang, Hongyan; Wang, Manna; Chen, Ang; Ning, Xiangkai; Yu, Kaitao; Li, Qihong; Li, Wen; Ma, Li; Chen, Zhaolie; Wang, Xiaoning; Sun, Qiang

    2015-04-27

    Cell-in-cell structures (CICs), characterized by the presence of one or more viable cells inside another one, were recently found important player in development, immune homeostasis and tumorigenesis etc. Incompatible with ever-increasing interests on this unique phenomenon, reliable methods available for high throughput quantification and systemic investigation are lacking. Here, we report a flow cytometry-based method for rapid analysis and sorting of heterotypic CICs formed between lymphocytes and tumor cells. In this method, cells were labeled with fluorescent dyes for fluorescence-activated cell sorting (FACS) by flow cytometry, conditions for reducing cell doublets were optimized such that high purity (>95%) of CICs could be achieved. By taking advantage of this method, we analyzed CICs formation between different cell pairs, and found that factors from both internalized effector cells and engulfing target cells affect heterotypic CICs formation. Thus, flow cytometry-based FACS analysis would serve as a high throughput method to promote systemic researches on CICs.

  13. Advanced Composite Bipolar Plate for Unitized Regenerative Fuel Cell/Electrolyzer Systems Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Development of an advanced composite bipolar plate is proposed for a unitized regenerative fuel cell and electrolyzer system that operates on pure feed streams...

  14. Super Unit Cells in Aperture-Based Metamaterials

    OpenAIRE

    Dragan Tanasković; Zoran Jakšić; Marko Obradov; Olga Jakšić

    2015-01-01

    An important class of electromagnetic metamaterials are aperture-based metasurfaces. Examples include extraordinary optical transmission arrays and double fishnets with negative refractive index. We analyze a generalization of such metamaterials where a simple aperture is now replaced by a compound object formed by superposition of two or more primitive objects (e.g., rectangles, circles, and ellipses). Thus obtained “super unit cell” shows far richer behavior than the subobjects that compris...

  15. [Contributions and results of lipo-structure in repair and rejuvenation of frontal anatomical unit].

    Science.gov (United States)

    Chichery, A; Mojallal, A; Voulliaume, D; Comparin, J-P; Foyatier, J-L

    2009-04-01

    Forehead is the most large anatomical unit of face. It includes forehead and anterior part of temple. Deteriorations of frontal anatomical units are numerous, ageing forehead has atrophy with eyebrow ptosis. In this work, we want to estimate contribution of lipo-structure in repair and rejuvenation of frontal anatomical unit (FAU). We present seven cases of repair of FAU and three cases of rejuvenation of the forehead. Results are satisfactory, particularly about frontal band. Results are questionable about Lipo-structure of temple. Applications of Lipo-structure in plastic and aesthetic surgery of the forehead are huge. Lipo-structure is the reference technique of volumetric filling. It is preferred to other techniques as flaps (pediculed or free) or materials, because it is a safe, easy and efficient technique, which permits large fillings. In aesthetic surgery, Lipo-structure gives volume to eyebrow region and fills root of the nose. It can be used with injections of botulinum toxin A. Lipo-structure of forehead takes part in rejuvenation of eye and nose. In conclusion, lipo-structure is actually the major technique of filling with a large implication in plastic and aesthetic surgery of FAU.

  16. Reaggregation of human, chick, and human embryonic brain cells. Factors influencing the formation of a histiotypic unit.

    Science.gov (United States)

    Lodin, Z; Fleischmannová, V; Hájková, B; Faltin, J; Hartman, J

    1981-01-01

    1. Aggregation of embryo human, mouse, and chick brain cells was studied. The optimum age interval of donors from different species was determined. 2. The significance of different dissociation procedures (mild trypsinisation followed by sieving, trypsinisation + DNA digestion, mechanical dissociation in 1 or 2 steps, and Ca2+ chelation by EGTA) for the rate of aggregation was estimated. A significant reduction of aggregation was observed after one step mechanical dissociation. Nonspecific adhesion of cells on DNA molecules was found only during the first stages of aggregation. 3. The curve of aggregation kinetics follows the curve of floculation kinetics. 90% free cells disappear from the medium after 2 h of aggregation and a large number of microaggregates are formed which condense after 20 to 24 h into compact aggregates. The time course of aggregation was similar for all cells dissociated by different means. Small differences in the rate of aggregation, caused by dissociation procedures, were apparent only during the first stages of aggregation. 4. The histiotypic unit formed by aggregation of human, mouse, and chick embryo brain cells exhibits some common and some specific features. During aggregation a multiple structural reconstruction takes place and a limited number of cells are exchanged or sorted out from aggregates into the medium. 5. The structural organisation of aggregates from differently dissociated cells differs in several aspects. This indicates that membrane surface structures are influenced differently by dissociation and behave differently during distinct stages of aggregation.

  17. Overview of commercialization of stationary fuel cell power plants in the United States

    Energy Technology Data Exchange (ETDEWEB)

    Hooie, D.T.; Williams, M.C.

    1995-07-01

    In this paper, DOE`s efforts to assist private sector organizations to develop and commercialize stationary fuel cell power plants in the United States are discussed. The paper also provides a snapshot of the status of stationary power fuel cell development occurring in the US, addressing all fuel cell types. This paper discusses general characteristics, system configurations, and status of test units and demonstration projects. The US DOE, Morgantown Energy Technology Center is the lead center for implementing DOE`s program for fuel cells for stationary power.

  18. Dielectric Behavior of Low Microwave Loss Unit Cell for All Dielectric Metamaterial

    OpenAIRE

    Tianhuan Luo; Bo Li; Qian Zhao; Ji Zhou

    2015-01-01

    With a deep study of the metamaterial, its unit cells have been widely extended from metals to dielectrics. The dielectric based unit cells attract much attention because of the advantage of easy preparation, tunability, and higher frequency response, and so forth. Using the conventional solid state method, we prepared a kind of incipient ferroelectrics (calcium titanate, CaTiO3) with higher microwave permittivity and lower loss, which can be successfully used to construct metamaterials. The ...

  19. Recent insights into the cell biology of thyroid angiofollicular units.

    OpenAIRE

    Colin, Ides M.; Denef, Jean-François; Lengelé, Benoît; Many, Marie-Christine; Gérard, Anne-Catherine

    2013-01-01

    In thyrocytes, cell polarity is of crucial importance for proper thyroid function. Many intrinsic mechanisms of self-regulation control how the key players involved in thyroid hormone (TH) biosynthesis interact in apical microvilli, so that hazardous biochemical processes may occur without detriment to the cell. In some pathological conditions, this enzymatic complex is disrupted, with some components abnormally activated into the cytoplasm, which can lead to further morphological and functio...

  20. Synthesis, Structure, and Rigid Unit Mode-like Anisotropic Thermal Expansion of BaIr2In9.

    Science.gov (United States)

    Calta, Nicholas P; Han, Fei; Kanatzidis, Mercouri G

    2015-09-08

    This Article reports the synthesis of large single crystals of BaIr2In9 using In flux and their characterization by variable-temperature single-crystal and synchrotron powder X-ray diffraction, resistivity, and magnetization measurements. The title compound adopts the BaFe2Al9-type structure in the space group P6/mmm with room temperature unit cell parameters a = 8.8548(6) Å and c = 4.2696(4) Å. BaIr2In9 exhibits anisotropic thermal expansion behavior with linear expansion along the c axis more than 3 times larger than expansion in the ab plane between 90 and 400 K. This anisotropic expansion originates from a rigid unit mode-like mechanism similar to the mechanism of zero and negative thermal expansion observed in many anomalous thermal expansion materials such as ZrW2O8 and ScF3.

  1. Development of integrated DMFC and PEM fuel cell units. Final report; Udvikling af integrerede DMFC og PEM braendselscelle enheder. Slutrapport

    Energy Technology Data Exchange (ETDEWEB)

    Odgaard, M. (IRD Fuel Cell Technology, Svendborg (DK))

    2007-06-15

    The 36-month long project 'Development of integrated DMFC and PEM fuel cell units' has been completed. The project goal was to develop a completely new MEA concept for integrated PEM and DMFC unit cells with enhanced power density and in this way obtain a price reduction. The integrated unit cell consists of a MEA, a gas diffusion layer with flow fields completed with bipolar plates and seals. The main focus of the present project was to: 1) Develop new catalyst materials fabricated by the use of FSD (flame spray deposition method). 2) Optimisation of the state-of-the-art MEA materials and electrode structure. 3) Implementation of a model to account for the CO poisoning of PEM fuel cells. Results and progress obtained in the project established that the individual unit cell components were able to meet and follow the road map of LT-PEM FC regarding electrode catalyst loading and fulfilled the targets for Year 2006. The project has resulted in some important successes. The highlights are as follows: The project has resulted in some important successes. The highlights are as follows: 1) MEA structure knowledge acquired in the project provide a sound basis for further progress. 2) A novel method for the synthesis of electrode by using flame spray synthesis was explored. 3) Electrochemical and catalytic behaviours of catalysts activity for CH{sub 3}OH explored. 4) Implementation of a sub model to account for the CO poisoning of PEM FC has been developed. 5) Numerical study of the flow distribution in FC manifolds was developed and completed with experimental data. 6) The electrode catalyst loading targets for year 2006 achieved. 7) The DMFC MEA performance has been improved by 35%. 8) Optimisation of the MEAs fabrication process has been successfully developed. 9) A new simple flow field design has been designed. 10) A procedure for integrated seals has been developed (au)

  2. Structural Vulnerability and Health: Latino Migrant Laborers in the United States

    Science.gov (United States)

    Quesada, James; Hart, Laurie K.; Bourgois, Philippe

    2011-01-01

    Latino immigrants in the United States constitute a paradigmatic case of a population group subject to structural violence. Their subordinated location in the global economy and their culturally depreciated status in the United States are exacerbated by legal persecution. Medical Anthropology Volume 30, issues 4 and 5, include a series of ethnographic analyses of the processes that render undocumented Latino immigrants structurally vulnerable to ill-health. We hope to extend the social science concept of ‘structural vulnerability’ to make it a useful tool for health care. Defined as a positionality that imposes physical/emotional suffering on specific population groups and individuals in patterned ways, structural vulnerability is a product of two complementary forces: (1) class-based economic exploitation and cultural, gender/sexual, and racialized discrimination; and (2) processes of symbolic violence and subjectivity formation that have increasingly legitimized punitive neoliberal discourses of individual unworthiness. PMID:21777121

  3. Hemolysin coregulated protein 1 as a molecular gluing unit for the assembly of nanoparticle hybrid structures

    Directory of Open Access Journals (Sweden)

    Tuan Anh Pham

    2016-03-01

    Full Text Available Hybrid nanoparticle (NP structures containing organic building units such as polymers, peptides, DNA and proteins have great potential in biosensor and electronic applications. The nearly free modification of the polymer chain, the variation of the protein and DNA sequence and the implementation of functional moieties provide a great platform to create inorganic structures of different morphology, resulting in different optical and magnetic properties. Nevertheless, the design and modification of a protein structure with functional groups or sequences for the assembly of biohybrid materials is not trivial. This is mainly due to the sensitivity of its secondary, tertiary and quaternary structure to the changes in the interaction (e.g., hydrophobic, hydrophilic, electrostatic, chemical groups between the protein subunits and the inorganic material. Here, we use hemolysin coregulated protein 1 (Hcp1 from Pseudomonas aeruginosa as a building and gluing unit for the formation of biohybrid structures by implementing cysteine anchoring points at defined positions on the protein rim (Hcp1_cys3. We successfully apply the Hcp1_cys3 gluing unit for the assembly of often linear, hybrid structures of plasmonic gold (Au NP, magnetite (Fe3O4 NP, and cobalt ferrite nanoparticles (CoFe2O4 NP. Furthermore, the assembly of Au NPs into linear structures using Hcp1_cys3 is investigated by UV–vis spectroscopy, TEM and cryo-TEM. One key parameter for the formation of Au NP assembly is the specific ionic strength in the mixture. The resulting network-like structure of Au NPs is characterized by Raman spectroscopy, showing surface-enhanced Raman scattering (SERS by a factor of 8·104 and a stable secondary structure of the Hcp1_cys3 unit. In order to prove the catalytic performance of the gold hybrid structures, they are used as a catalyst in the reduction reaction of 4-nitrophenol showing similar catalytic activity as the pure Au NPs. To further extend the

  4. Dominant unit CD34+ cell dose predicts engraftment after double-unit cord blood transplantation and is influenced by bank practice.

    Science.gov (United States)

    Purtill, Duncan; Smith, Katherine; Devlin, Sean; Meagher, Richard; Tonon, Joann; Lubin, Marissa; Ponce, Doris M; Giralt, Sergio; Kernan, Nancy A; Scaradavou, Andromachi; Stevens, Cladd E; Barker, Juliet N

    2014-11-06

    We investigated the unit characteristics associated with engraftment after double-unit cord blood (CB) transplantation (dCBT) and whether these could be reliably identified during unit selection. Cumulative incidence of neutrophil engraftment in 129 myeloablative dCBT recipients was 95% (95% confidence interval: 90-98%). When precryopreservation characteristics were analyzed, the dominant unit CD34(+) cell dose was the only characteristic independently associated with engraftment (hazard ratio, 1.43; P = .002). When postthaw characteristics were also included, only dominant unit infused viable CD34(+) cell dose independently predicted engraftment (hazard ratio, 1.95; P banks were more likely to have low recovery (P banks and units with cryovolumes other than 24.5 to 26.0 mL were more likely to have poor postthaw viability. Precryopreservation CD34(+) cell dose and banking practices should be incorporated into CB unit selection.

  5. Can technical, functional and structural characteristics of dental units predict Legionella pneumophila and Pseudomonas aeruginosa contamination?

    Science.gov (United States)

    Aprea, Luigi; Cannova, Lucia; Firenze, Alberto; Bivona, Maria S; Amodio, Emanuele; Romano, Nino

    2010-12-01

    Legionella pneumophila and Pseudomonas aeruginosa are common colonizers of water environments, particularly dental unit waterlines. The aim of this study was to assess whether the technical, functional and structural characteristics of dental units can influence the presence and the levels of opportunistic pathogens. Overall, 42 water samples were collected from dental units in a teaching hospital in Palermo, Italy, including 21 samples from the 21 taps supplied by the municipal water distribution system and 21 samples from oral rinsing cups at 21 dental units. L. pneumophila was present in 16 out of 21 water samples (76.2%) from dental units, and the median concentration was higher in samples from oral rinsing cups than in those from taps (P < 0.001). P. aeruginosa was equally distributed in water samples collected from oral rinsing cups and from taps. Some characteristics of dental units (age, number of chairs per room, number of patients per day and water temperature) were slightly associated with the presence of P. aeruginosa, but not with contamination by L. pneumophila. Our experience suggests that L. pneumophila is frequently detected in dental units, as reported in previous studies, whereas P. aeruginosa is not a frequent contaminant. As a consequence, microbiological control of water quality should be routinely performed, and should include the detection of opportunistic pathogens when bacterial contamination is expected.

  6. Fuel cell repeater unit including frame and separator plate

    Energy Technology Data Exchange (ETDEWEB)

    Yamanis, Jean; Hawkes, Justin R; Chiapetta, Jr., Louis; Bird, Connie E; Sun, Ellen Y; Croteau, Paul F

    2013-11-05

    An example fuel cell repeater includes a separator plate and a frame establishing at least a portion of a flow path that is operative to communicate fuel to or from at least one fuel cell held by the frame relative to the separator plate. The flow path has a perimeter and any fuel within the perimeter flow across the at least one fuel cell in a first direction. The separator plate, the frame, or both establish at least one conduit positioned outside the flow path perimeter. The conduit is outside of the flow path perimeter and is configured to direct flow in a second, different direction. The conduit is fluidly coupled with the flow path.

  7. Molecular structure of basic oligomeric building units of heparan-sulfate glycosaminoglycans

    NARCIS (Netherlands)

    Remko, Milan; Van Duijnen, Piet Th.; Broer, Ria

    2010-01-01

    This study reports in detail the results of systematic large-scale theoretical investigations of the acidic dimeric structural units (D-E, E-F, F-G, and G-H) and pentamer D-E-F-G-H (fondaparinux) of the glycosaminoglycan heparin, and their anionic forms. The geometries and energies of these oligomer

  8. Quaternary Structure and Functional Unit of Energy Coupling Factor (ECF)-type Transporters

    NARCIS (Netherlands)

    Beek, Josy ter; Duurkens, Ria H.; Erkens, Guus B.; Slotboom, Dirk Jan

    2011-01-01

    ATP-binding cassette (ABC) transporters mediate transport of diverse substrates across membranes. We have determined the quaternary structure and functional unit of the recently discovered ECF-type (energy coupling factor) of ABC transporters, which is widespread among prokaryotes. ECF transporters

  9. Mechanical Properties and Fatigue Behavior of Unitized Composite Airframe Structures at Elevated Temperature

    Science.gov (United States)

    2016-09-01

    suitability of this composite for use in aerospace components designed to contain high-temperature environments, mechanical tests were performed under... contain high-temperature environments, mechanical tests were performed under temperature conditions simulating the actual operating conditions. In all... MECHANICAL PROPERTIES AND FATIGUE BEHAVIOR OF UNITIZED COMPOSITE AIRFRAME STRUCTURES AT ELEVATED

  10. Regional impacts of technical change: the case of structural particleboard in the United States.

    Science.gov (United States)

    Zhi Xu; David N. Bengston; Hans M. Gregersen; Allen L. Lundgren

    1992-01-01

    Analyzes the regional impacts of research benefits in the United States due to the introduction of structural particleboard. The distribution of consumer benefits, producer benefits, direct employment impacts, and changes in wood requirements are analyzed for the four census regions. The distribution of benefits is found to differ widely between regions, indicating...

  11. Evaluation of the pneumatic tube system for transportation of packed red cell units

    Directory of Open Access Journals (Sweden)

    Supriya Dhar

    2015-01-01

    Full Text Available Background: Pneumatic tube system (PTS is commonly used in hospital settings to transport blood samples to diagnostic laboratories. At our blood center, we receive blood requisitions via the PTS, but units are carried to the ward by human courier. Recently we considered using the PTS for transporting blood units. Since, there are reports of hemolysis in blood samples sent through the PTS, we evaluated this system for transporting red cell units. Aims: The aim was to assess the effect of PTS transport on the quality of packed red cell units. Materials and Methods: A total of 50 red blood cells units (RBC, (25 non-irradiated and 25 irradiated were subjected to transportation through the PTS. The control arm in the study was age-matched RBC units not subjected to PTS transport. Each RBC unit was evaluated for hemoglobin (Hb, lactate dehydrogenase, potassium and plasma hemoglobin (Hb. The paired t-test was used to compare these parameters, and the P value was calculated. Results and Conclusion: The percentage of hemolysis after transportation through PTS was below the recommended guidelines. Delivery of the blood unit to the wrong station, bags lying unattended at the destination were few of the problems that had to be addressed. To conclude, though the PTS is a safe means of transporting blood products with reduction in the turn-around-time, it must be validated before use.

  12. Effects of Dexamethasone on Satellite Cells and Tissue Engineered Skeletal Muscle Units.

    Science.gov (United States)

    Syverud, Brian C; VanDusen, Keith W; Larkin, Lisa M

    2016-03-01

    Tissue engineered skeletal muscle has potential for application as a graft source for repairing soft tissue injuries, a model for testing pharmaceuticals, and a biomechanical actuator system for soft robots. However, engineered muscle to date has not produced forces comparable to native muscle, limiting its potential for repair and for use as an in vitro model for pharmaceutical testing. In this study, we examined the trophic effects of dexamethasone (DEX), a glucocorticoid that stimulates myoblast differentiation and fusion into myotubes, on our tissue engineered three-dimensional skeletal muscle units (SMUs). Using our established SMU fabrication protocol, muscle isolates were cultured with three experimental DEX concentrations (5, 10, and 25 nM) and compared to untreated controls. Following seeding onto a laminin-coated Sylgard substrate, the administration of DEX was initiated on day 0 or day 6 in growth medium or on day 9 after the switch to differentiation medium and was sustained until the completion of SMU fabrication. During this process, total cell proliferation was measured with a BrdU assay, and myogenesis and structural advancement of muscle cells were observed through immunostaining for MyoD, myogenin, desmin, and α-actinin. After SMU formation, isometric tetanic force production was measured to quantify function. The histological and functional assessment of the SMU showed that the administration of 10 nM DEX beginning on either day 0 or day 6 yielded optimal SMUs. These optimized SMUs exhibited formation of advanced sarcomeric structure and significant increases in myotube diameter and myotube fusion index, compared with untreated controls. Additionally, the optimized SMUs matured functionally, as indicated by a fivefold rise in force production. In conclusion, we have demonstrated that the addition of DEX to our process of engineering skeletal muscle tissue improves myogenesis, advances muscle structure, and increases force production in the

  13. Control of an afterburner in a diesel fuel cell power unit under variable load

    Science.gov (United States)

    Dolanc, Gregor; Pregelj, Boštjan; Petrovčič, Janko; Samsun, Remzi Can

    2017-01-01

    In this paper, the control system for a catalytic afterburner in a diesel fuel cell auxiliary power unit is presented. The catalytic afterburner is used to burn the non-utilised hydrogen and other possible combustible components of the fuel cell anode off-gas. To increase the energy efficiency of the auxiliary power unit, the thermal energy released in the catalytic afterburner is utilised to generate the steam for the fuel processor. For optimal operation of the power unit in all modes of operation including load change, stable steam generation is required and overall energy balance must be kept within design range. To achieve this, the reaction temperature of the catalytic afterburner must be stable in all modes of operation. Therefore, we propose the afterburner temperature control based on mass and thermal balances. Finally, we demonstrate the control system using the existing prototype of the diesel fuel cell auxiliary power unit.

  14. Structural analysis of cell wall polysaccharides using PACE

    Energy Technology Data Exchange (ETDEWEB)

    Mortimer, Jennifer C. [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Joint BioEnergy Institute

    2017-01-01

    The plant cell wall is composed of many complex polysaccharides. The composition and structure of the polysaccharides affect various cell properties including cell shape, cell function and cell adhesion. Many techniques to characterize polysaccharide structure are complicated, requiring expensive equipment and specialized operators e.g. NMR, MALDI-MS. PACE (Polysaccharide Analysis using Carbohydrate gel Electrophoresis) uses a simple, rapid technique to analyze polysaccharide quantity and structure (Goubet et al. 2002). Whilst the method here describes xylan analysis, it can be applied (by use of the appropriate glycosyl hydrolase) to any cell wall polysaccharide.

  15. Efficiency of the unit cell in rectangular finned tube arrangements

    Energy Technology Data Exchange (ETDEWEB)

    Buzzoni, Luca; Dall' Olio, Roberto; Spiga, Marco [Bologna Univ., DIENCA, Bologna (Italy)

    1999-11-01

    This paper is aimed at presenting an investigation concerning the efficiency of the single unit in finned air-cooled heat exchangers with staggered and in-line bundles of rectangular ducts, where a hot process fluid flows inside extended-surface tubes and atmospheric air is circulated outside, over the extended surface. The differential energy equation is numerically solved by a finite difference technique, in order to determine the spatial temperature profiles, then the fin efficiency and the augmentation factor are calculated by a simple numerical integration. The results show that the temperature distribution and the fin performance depend on four dimensionless parameters (m,{beta},p{sub x},p{sub y}), the first accounting for the heat transfer condition, the other ones accounting for the geometry of the extended surface (tube aspect ratio and pitches). Several tables are presented, allowing the efficiency of the extended surface to be deduced as a function of the thermal and geometric parameters. (Author)

  16. Quantification of Cell-Free DNA in Red Blood Cell Units in Different Whole Blood Processing Methods

    Directory of Open Access Journals (Sweden)

    Andrew W. Shih

    2016-01-01

    Full Text Available Background. Whole blood donations in Canada are processed by either the red cell filtration (RCF or whole blood filtration (WBF methods, where leukoreduction is potentially delayed in WBF. Fresh WBF red blood cells (RBCs have been associated with increased in-hospital mortality after transfusion. Cell-free DNA (cfDNA is released by neutrophils prior to leukoreduction, degraded during RBC storage, and is associated with adverse patient outcomes. We explored cfDNA levels in RBCs prepared by RCF and WBF and different storage durations. Methods. Equal numbers of fresh (stored ≤14 days and older RBCs were sampled. cfDNA was quantified by spectrophotometry and PicoGreen. Separate regression models determined the association with processing method and storage duration and their interaction on cfDNA. Results. cfDNA in 120 RBC units (73 RCF, 47 WBF were measured. Using PicoGreen, WBF units overall had higher cfDNA than RCF units (p=0.0010; fresh WBF units had higher cfDNA than fresh RCF units (p=0.0093. Using spectrophotometry, fresh RBC units overall had higher cfDNA than older units (p=0.0031; fresh WBF RBCs had higher cfDNA than older RCF RBCs (p=0.024. Conclusion. Higher cfDNA in fresh WBF was observed compared to older RCF blood. Further study is required for association with patient outcomes.

  17. High performance internal reforming unit for high temperature fuel cells

    Science.gov (United States)

    Ma, Zhiwen; Venkataraman, Ramakrishnan; Novacco, Lawrence J.

    2008-10-07

    A fuel reformer having an enclosure with first and second opposing surfaces, a sidewall connecting the first and second opposing surfaces and an inlet port and an outlet port in the sidewall. A plate assembly supporting a catalyst and baffles are also disposed in the enclosure. A main baffle extends into the enclosure from a point of the sidewall between the inlet and outlet ports. The main baffle cooperates with the enclosure and the plate assembly to establish a path for the flow of fuel gas through the reformer from the inlet port to the outlet port. At least a first directing baffle extends in the enclosure from one of the sidewall and the main baffle and cooperates with the plate assembly and the enclosure to alter the gas flow path. Desired graded catalyst loading pattern has been defined for optimized thermal management for the internal reforming high temperature fuel cells so as to achieve high cell performance.

  18. Theoretical characterization and design of small molecule donor material containing naphthodithiophene central unit for efficient organic solar cells.

    Science.gov (United States)

    Duan, Yu-Ai; Geng, Yun; Li, Hai-Bin; Jin, Jun-Ling; Wu, Yong; Su, Zhong-Min

    2013-07-15

    To seek for high-performance small molecule donor materials used in heterojunction solar cell, six acceptor-donor-acceptor small molecules based on naphtho[2,3-b:6,7-b']dithiophene (NDT) units with different acceptor units were designed and characterized using density functional theory and time-dependent density functional theory. Their geometries, electronic structures, photophysical, and charge transport properties have been scrutinized comparing with the reported donor material NDT(TDPP)2 (TDPP  =  thiophene-capped diketopyrrolopyrrole). The open circuit voltage (V(oc)), energetic driving force(ΔE(L-L)), and exciton binding energy (E(b)) were also provided to give an elementary understanding on their cell performance. The results reveal that the frontier molecular orbitals of 3-7 match well with the acceptor material PC61 BM, and compounds 3-5 were found to exhibit the comparable performances to 1 and show promising potential in organic solar cells. In particular, comparing with 1, system 7 with naphthobisthiadiazole acceptor unit displays broader absorption spectrum, higher V(oc), lower E(b), and similar carrier mobility. An in-depth insight into the nature of the involved excited states based on transition density matrix and charge density difference indicates that all S1 states are mainly intramolecular charge transfer states with the charge transfer from central NDT unit to bilateral acceptor units, and also imply that the exciton of 7 can be dissociated easily due to its large extent of the charge transfer. In a word, 7 maybe superior to 1 and may act as a promising donor candidate for organic solar cell. Copyright © 2013 Wiley Periodicals, Inc.

  19. The Daniell cell, Ohm's law, and the emergence of the International System of Units

    Science.gov (United States)

    Jayson, Joel S.

    2014-01-01

    Telegraphy originated in the 1830s and 40 s and flourished in the following decades but with a patchwork of electrical standards. Electromotive force was for the most part measured in units of the predominant Daniell cell, but each telegraphy company had their own resistance standard. In 1862, the British Association for the Advancement of Science formed a committee to address this situation. By 1873, they had given definition to the electromagnetic system of units (emu) and defined the practical units of the ohm as 109 emu units of resistance and the volt as 108 emu units of electromotive force. These recommendations were ratified and expanded upon in a series of international congresses held between 1881 and 1904. A proposal by Giovanni Giorgi in 1901 took advantage of a coincidence between the conversion of the units of energy in the emu system (the erg) and in the practical system (the Joule). As it was, the same conversion factor existed between the cgs based emu system and a theretofore undefined MKS system. By introducing another unit X (where X could be any of the practical electrical units), Giorgi demonstrated that a self-consistent MKSX system was tenable without the need for multiplying factors. Ultimately, the ampere was selected as the fourth unit. It took nearly 60 years, but in 1960, Giorgi's proposal was incorporated as the core of the newly inaugurated International System of Units (SI). This article surveys the physics, physicists, and events that contributed to those developments.

  20. A large format in operando wound cell for analysing the structural dynamics of lithium insertion materials

    Science.gov (United States)

    Brant, William R.; Roberts, Matthew; Gustafsson, Torbjörn; Biendicho, Jordi Jacas; Hull, Stephen; Ehrenberg, Helmut; Edström, Kristina; Schmid, Siegbert

    2016-12-01

    This paper presents a large wound cell for in operando neutron diffraction (ND) from which high quality diffraction patterns are collected every 15 min while maintaining conventional electrochemical performance. Under in operando data collection conditions the oxygen atomic displacement parameters (ADPs) and cell parameters were extracted for Li0.18Sr0.66Ti0.5Nb0.5O3. Analysis of diffraction data collected under in situ conditions revealed that the lithium is located on the (0.5 0.5 0) site, corresponding to the 3c Wyckoff position in the cubic perovskite unit cell, after the cell is discharged to 1 V. When the cell is discharged under potentiostatic conditions the quantity of lithium on this site increases, indicating a potential position where lithium becomes pinned in the thermodynamically stable phase. During this potentiostatic step the oxygen ADPs reduce significantly. On discharge, however, the oxygen ADPs were observed to increase gradually as more lithium is inserted into the structure. Finally, the rate of unit cell expansion changed by ∼44% once the lithium content approached ∼0.17 Li per formula unit. A link between lithium content and degree of mobility, disorder of the oxygen positions and changing rate of unit cell expansion at various stages during lithium insertion and extraction is thus presented.

  1. Occupational structure and socioeconomic inequality: a comparative study between Brazil and the United States

    Directory of Open Access Journals (Sweden)

    Alexandre Gori Maia

    2015-08-01

    Full Text Available ABSTRACTThis paper explores how occupational structure is associated with economic inequality in Brazil in comparison to the United States. Changes in the Brazilian and American occupational structures between 1983 and 2011 are investigated in order to assess how closely they generate high socioeconomic inequalities. The effects of education, age, gender and race on occupational attainment are taken into account. Highlights of the results include: (1 a higher level of socioeconomic development in the American occupational structure, reflecting huge socioeconomic differences between these countries; (2 a tenuous convergence between the Brazilian and American occupational structures; (3 a significant decrease in the net impacts of education, age, gender and race on occupational attainment (i.e., reduced social stratification in both countries. These results suggest the analytical worth of considering occupational structure as a significant intermediate variable affecting the level of socioeconomic inequality within a country over time, as well as between two countries at a given point in time.

  2. [THE MODEL OF NEUROVASCULAR UNIT IN VITRO CONSISTING OF THREE CELLS TYPES].

    Science.gov (United States)

    Khilazheva, E D; Boytsova, E B; Pozhilenkova, E A; Solonchuk, Yu R; Salmina, A B

    2015-01-01

    There are many ways to model blood brain barrier and neurovascular unit in vitro. All existing models have their disadvantages, advantages and some peculiarities of preparation and usage. We obtained the three-cells neurovascular unit model in vitro using progenitor cells isolated from the rat embryos brain (Wistar, 14-16 d). After withdrawal of the progenitor cells the neurospheres were cultured with subsequent differentiation into astrocytes and neurons. Endothelial cells were isolated from embryonic brain too. During the differentiation of progenitor cells the astrocytes monolayer formation occurs after 7-9 d, neurons monolayer--after 10-14 d, endothelial cells monolayer--after 7 d. Our protocol for simultaneous isolation and cultivation of neurons, astrocytes and endothelial cells reduces the time needed to obtain neurovascular unit model in vitro, consisting of three cells types and reduce the number of animals used. It is also important to note the cerebral origin of all cell types, which is also an advantage of our model in vitro.

  3. Importance of unit cells in accurate evaluation of the characteristics of graphene

    Energy Technology Data Exchange (ETDEWEB)

    Sabzyan, Hassan; Sadeghpour, Narges [Isfahan Univ. (Iran, Islamic Republic of). Dept. of Chemistry

    2016-08-01

    Effects of the size of the unit cell on energy, atomic charges, and phonon frequencies of graphene at the Γ point of the Brillouin zone are studied in the absence and presence of an electric field using density functional theory (DFT) methods (LDA and DFT-PBE functionals with Goedecker-Teter-Hutter (GTH) and Troullier-Martins (TM) norm-conserving pseudopotentials). Two types of unit cells containing n{sub c}=4-28 carbon atoms are considered. Results show that stability of graphene increases with increasing size of the unit cell. Energy, atomic charges, and phonon frequencies all converge above n{sub c}=24 for all functional-pseudopotentials used. Except for the LDA-GTH calculations, application of an electric field of 0.4 and 0.9 V/nm strengths does not change the trends with the size of the unit cell but instead slightly decreases the binding energy of graphene. Results of this study show that the choice of unit cell size and type is critical for calculation of reliable characteristics of graphene.

  4. Cell fine structure and function - Past and present

    Science.gov (United States)

    Fernandez-Moran, H.

    1970-01-01

    Electron microscopic studies of nerve membrane fine structure, discussing cell membrane multienzyme and macromolecular energy and information transduction, protein synthesis and nucleic acids interrelations

  5. Modelling Structure-Property Relationship for Copolymers by Structured Representation of Repeating Units

    Science.gov (United States)

    Bertinetto, Carlo; Duce, Celia; Micheli, Alessio; Starita, Antonina; Solaro, Roberto; Tiné, Maria R.

    2009-08-01

    We report here a recent study on the prediction by recursive neural network of the glass transition temperature of (meth)acrylic copolymers, for which appropriate structured representations are proposed. It is shown that the flexibility of such description allows for simultaneously treating different classes of compounds as well as accounting for different average properties such as tacticity and molar composition.

  6. New photosensitizer with phenylenebisthiophene central unit and cyanovinylene 4-nitrophenyl terminal units for dye-sensitized solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Mikroyannidis, J.A., E-mail: mikroyan@chemistry.upatras.gr [Chemical Technology Laboratory, Department of Chemistry, University of Patras, GR-26500 Patras (Greece); Suresh, P. [Physics Department, Molecular Electronic and Optoelectronic Device Laboratory, JNV University, Jodhpur (Raj.) 342005 (India); Roy, M.S. [Defence Laboratory, Jodhpur (Raj.) 342011 (India); Sharma, G.D., E-mail: sharmagd_in@yahoo.com [Physics Department, Molecular Electronic and Optoelectronic Device Laboratory, JNV University, Jodhpur (Raj.) 342005 (India); R and D Centre for Engineering and Science, Jaipur Engineering College, Kukas, Jaipur (Raj.) (India)

    2011-06-30

    Graphical abstract: A novel dye D was synthesized and used as photosensitizer for quasi solid state dye-sensitized solar cells. A power conversion efficiency of 4.4% was obtained which was improved to 5.52% when diphenylphosphinic acid (DPPA) was added as coadsorbent. Display Omitted Highlights: > A new low band gap photosensitizer with cyanovinylene 4-nitrophenyl terminal units was synthesized. > A power conversion efficiency of 4.4% was obtained for the dye-sensitized solar cell based on this photosensitizer. > The power conversion efficiency of the dye-sensitized solar cell was further improved to 5.52% when diphenylphosphinic acid was added as coadsorbent. - Abstract: A new low band gap photosensitizer, D, which contains 2,2'-(1,4-phenylene) bisthiophene central unit and cyanovinylene 4-nitrophenyl terminal units at both sides was synthesized. The two carboxyls attached to the 2,5-positions of the phenylene ring act as anchoring groups. Dye D was soluble in common organic solvents, showed long-wavelength absorption maximum at 620-636 nm and optical band gap of 1.72 eV. The electrochemical parameters, i.e. the highest occupied molecular orbital (HOMO) (-5.1 eV) and the lowest unoccupied molecular orbital (LUMO) (-3.3 eV) energy levels of D show that this dye is suitable as molecular sensitizer. The quasi solid state dye-sensitized solar cell (DSSC) based on D shows a short circuit current (J{sub sc}) of 9.95 mA/cm{sup 2}, an open circuit voltage (V{sub oc}) of 0.70 V, and a fill factor (FF) of 0.64 corresponding to an overall power conversion efficiency (PCE) of 4.40% under 100 mW/cm{sup 2} irradiation. The overall PCE has been further improved to 5.52% when diphenylphosphinic acid (DPPA) coadsorbent is incorporated into the D solution. This increased PCE has been attributed to the enhancement in the electron lifetime and reduced recombination of injected electrons with the iodide ions present in the electrolyte with the use of DPPA as coadsorbant. The

  7. A taxonomy of state public health preparedness units: an empirical examination of organizational structure.

    Science.gov (United States)

    Menachemi, Nir; Yeager, Valerie A; Duncan, W Jack; Katholi, Charles R; Ginter, Peter M

    2012-01-01

    State public health preparedness units (SPHPUs) were developed in response to federal funding to improve response to disasters: a responsibility that had not traditionally been within the purview of public health. The SPHPUs were created within the existing public health organizational structure, and their placement may have implications for how the unit functions, how communication takes place, and ultimately how well the key responsibilities are performed. This study empirically identifies a taxonomy of similarly structured SPHPUs and examines whether this structure is associated with state geographic, demographic, and threat-vulnerability characteristics. Data representing each SPHPU were extracted from publically available sources, including organizational charts and emergency preparedness plans for 2009. A cross-sectional segmentation analysis was conducted of variables representing structural attributes. Fifty state public health departments. Variables representing "span of control" and "hierarchal levels" were extracted from organizational charts. Structural "complexity" and "centralization" were extracted from state emergency preparedness documents and other secondary sources. On average, 6.6 people report to the same manager as the SPHPU director; 2.1 levels separate the SPHPU director from the state health officer; and a mean of 13.5 agencies collaborate with SPHPU during a disaster. Despite considerable variability in how SPHPUs had been structured, results of the cluster and principal component analysis identified 7 similarly structured groups. Neither the taxonomic groups nor the individual variables representing structure were found to be associated with state characteristics, including threat vulnerabilities. Our finding supports the hypothesis that SPHPUs are seemingly inadvertently (eg, not strategically) organized. This taxonomy provides the basis for which future research can examine how SPHPU structure relates to performance measures and

  8. Accelerating large-scale protein structure alignments with graphics processing units

    Directory of Open Access Journals (Sweden)

    Pang Bin

    2012-02-01

    Full Text Available Abstract Background Large-scale protein structure alignment, an indispensable tool to structural bioinformatics, poses a tremendous challenge on computational resources. To ensure structure alignment accuracy and efficiency, efforts have been made to parallelize traditional alignment algorithms in grid environments. However, these solutions are costly and of limited accessibility. Others trade alignment quality for speedup by using high-level characteristics of structure fragments for structure comparisons. Findings We present ppsAlign, a parallel protein structure Alignment framework designed and optimized to exploit the parallelism of Graphics Processing Units (GPUs. As a general-purpose GPU platform, ppsAlign could take many concurrent methods, such as TM-align and Fr-TM-align, into the parallelized algorithm design. We evaluated ppsAlign on an NVIDIA Tesla C2050 GPU card, and compared it with existing software solutions running on an AMD dual-core CPU. We observed a 36-fold speedup over TM-align, a 65-fold speedup over Fr-TM-align, and a 40-fold speedup over MAMMOTH. Conclusions ppsAlign is a high-performance protein structure alignment tool designed to tackle the computational complexity issues from protein structural data. The solution presented in this paper allows large-scale structure comparisons to be performed using massive parallel computing power of GPU.

  9. A Miniaturized Antenna with Negative Index Metamaterial Based on Modified SRR and CLS Unit Cell for UWB Microwave Imaging Applications

    Directory of Open Access Journals (Sweden)

    Md. Moinul Islam

    2015-01-01

    Full Text Available A miniaturized antenna employing a negative index metamaterial with modified split-ring resonator (SRR and capacitance-loaded strip (CLS unit cells is presented for Ultra wideband (UWB microwave imaging applications. Four left-handed (LH metamaterial (MTM unit cells are located along one axis of the antenna as the radiating element. Each left-handed metamaterial unit cell combines a modified split-ring resonator (SRR with a capacitance-loaded strip (CLS to obtain a design architecture that simultaneously exhibits both negative permittivity and negative permeability, which ensures a stable negative refractive index to improve the antenna performance for microwave imaging. The antenna structure, with dimension of 16 × 21 × 1.6 mm3, is printed on a low dielectric FR4 material with a slotted ground plane and a microstrip feed. The measured reflection coefficient demonstrates that this antenna attains 114.5% bandwidth covering the frequency band of 3.4–12.5 GHz for a voltage standing wave ratio of less than 2 with a maximum gain of 5.16 dBi at 10.15 GHz. There is a stable harmony between the simulated and measured results that indicate improved nearly omni-directional radiation characteristics within the operational frequency band. The stable surface current distribution, negative refractive index characteristic, considerable gain and radiation properties make this proposed negative index metamaterial antenna optimal for UWB microwave imaging applications.

  10. A Miniaturized Antenna with Negative Index Metamaterial Based on Modified SRR and CLS Unit Cell for UWB Microwave Imaging Applications.

    Science.gov (United States)

    Islam, Md Moinul; Islam, Mohammad Tariqul; Samsuzzaman, Md; Faruque, Mohammad Rashed Iqbal; Misran, Norbahiah; Mansor, Mohd Fais

    2015-01-23

    A miniaturized antenna employing a negative index metamaterial with modified split-ring resonator (SRR) and capacitance-loaded strip (CLS) unit cells is presented for Ultra wideband (UWB) microwave imaging applications. Four left-handed (LH) metamaterial (MTM) unit cells are located along one axis of the antenna as the radiating element. Each left-handed metamaterial unit cell combines a modified split-ring resonator (SRR) with a capacitance-loaded strip (CLS) to obtain a design architecture that simultaneously exhibits both negative permittivity and negative permeability, which ensures a stable negative refractive index to improve the antenna performance for microwave imaging. The antenna structure, with dimension of 16 × 21 × 1.6 mm³, is printed on a low dielectric FR4 material with a slotted ground plane and a microstrip feed. The measured reflection coefficient demonstrates that this antenna attains 114.5% bandwidth covering the frequency band of 3.4-12.5 GHz for a voltage standing wave ratio of less than 2 with a maximum gain of 5.16 dBi at 10.15 GHz. There is a stable harmony between the simulated and measured results that indicate improved nearly omni-directional radiation characteristics within the operational frequency band. The stable surface current distribution, negative refractive index characteristic, considerable gain and radiation properties make this proposed negative index metamaterial antenna optimal for UWB microwave imaging applications.

  11. A Miniaturized Antenna with Negative Index Metamaterial Based on Modified SRR and CLS Unit Cell for UWB Microwave Imaging Applications

    Science.gov (United States)

    Islam, Md. Moinul; Islam, Mohammad Tariqul; Samsuzzaman, Md.; Faruque, Mohammad Rashed Iqbal; Misran, Norbahiah; Mansor, Mohd Fais

    2015-01-01

    A miniaturized antenna employing a negative index metamaterial with modified split-ring resonator (SRR) and capacitance-loaded strip (CLS) unit cells is presented for Ultra wideband (UWB) microwave imaging applications. Four left-handed (LH) metamaterial (MTM) unit cells are located along one axis of the antenna as the radiating element. Each left-handed metamaterial unit cell combines a modified split-ring resonator (SRR) with a capacitance-loaded strip (CLS) to obtain a design architecture that simultaneously exhibits both negative permittivity and negative permeability, which ensures a stable negative refractive index to improve the antenna performance for microwave imaging. The antenna structure, with dimension of 16 × 21 × 1.6 mm3, is printed on a low dielectric FR4 material with a slotted ground plane and a microstrip feed. The measured reflection coefficient demonstrates that this antenna attains 114.5% bandwidth covering the frequency band of 3.4–12.5 GHz for a voltage standing wave ratio of less than 2 with a maximum gain of 5.16 dBi at 10.15 GHz. There is a stable harmony between the simulated and measured results that indicate improved nearly omni-directional radiation characteristics within the operational frequency band. The stable surface current distribution, negative refractive index characteristic, considerable gain and radiation properties make this proposed negative index metamaterial antenna optimal for UWB microwave imaging applications. PMID:28787945

  12. Prediction of stress-strain behavior of ceramic matrix composites using unit cell model

    Directory of Open Access Journals (Sweden)

    Suzuki Takuya

    2015-01-01

    Full Text Available In this study, the elastic modulus and the stress-strain curve of ceramic matrix composites (CMCs were predicted by using the unit cell model that consists of fiber bundles and matrix. The unit cell model was developed based on the observation of cross sections of CMCs. The elastic modulus of CMCs was calculated from the results of finite element analysis using the developed model. The non-linear behavior of stress-strain curve of CMCs was also predicted by taking the degradation of the elastic modulus into consideration, where the degradation was related to the experimentally measured crack density in CMCs. The approach using the unit cell model was applied to two kinds of CMCs, and good agreement was obtained between the experimental and the calculated results.

  13. Reduction in potassium concentration of stored red blood cell units using a resin filter.

    Science.gov (United States)

    Yamada, Chisa; Heitmiller, Eugenie S; Ness, Paul M; King, Karen E

    2010-09-01

    Hyperkalemia is a serious complication of rapid and massive blood transfusion due to high plasma potassium (K) in stored red blood cell (RBC) units. A potassium adsorption filter (PAF) was developed in Japan to remove K by exchanging with sodium (Na). We performed an in vitro evaluation of its efficacy and feasibility of use. Three AS-3 RBC units were filtered by each PAF using gravity; 10 PAFs were tested. Blood group, age, flow rate, and irradiation status were recorded. Total volume, K, Na, Cl, Mg, total Ca (tCa), RBC count, hemoglobin (Hb), hematocrit (Hct), and plasma Hb were measured before and after filtering each unit. Ionized Ca (iCa), pH, and glucose were measured for some units. After filtration, the mean decrease in K was 97.5% in the first RBC unit, 91.2% in the second unit, and 64.4% in the third unit. The mean increases in Na, Mg, and tCa were 33.0, 151.4, and 116.1%, respectively. iCa and pH remained low; glucose was unchanged. RBC count, Hb, and Hct decreased slightly after filtration of first units; plasma Hb was unchanged. After filtration, there was no visual evidence of increased hemolysis or clot formation. The PAF decreased K concentration in stored AS-3 RBC units to minimal levels in the first and second RBC units. Optimally, one filter could be used for 2 RBC units. Although Na increased, the level may not be clinically significant. PAF may be useful for at-risk patients receiving older units or blood that has been stored after gamma irradiation. © 2010 American Association of Blood Banks.

  14. cellPACK: A Virtual Mesoscope to Model and Visualize Structural Systems Biology

    Science.gov (United States)

    Johnson, Graham T.; Autin, Ludovic; Al-Alusi, Mostafa; Goodsell, David S.; Sanner, Michel F.; Olson, Arthur J.

    2014-01-01

    cellPACK assembles computational models of the biological mesoscale, an intermediate scale (10−7–10−8m) between molecular and cellular biology. cellPACK’s modular architecture unites existing and novel packing algorithms to generate, visualize and analyze comprehensive 3D models of complex biological environments that integrate data from multiple experimental systems biology and structural biology sources. cellPACK is currently available as open source code, with tools for validation of models and with recipes and models for five biological systems: blood plasma, cytoplasm, synaptic vesicles, HIV and a mycoplasma cell. We have applied cellPACK to model distributions of HIV envelope protein to test several hypotheses for consistency with experimental observations. Biologists, educators, and outreach specialists can interact with cellPACK models, develop new recipes and perform packing experiments through scripting and graphical user interfaces at http://cellPACK.org. PMID:25437435

  15. Unit cell sparger test program and analysis of test results

    Energy Technology Data Exchange (ETDEWEB)

    Park, Choon Kyung; Song, C. H.; Cho, S.; Yoon, Y. J

    2003-11-01

    This report presents the results of test data from CPT-3 test and the effect of important parameters on the IRWST load. The object of CPT-3 test is to determine the influence of air mass in the piping on the IRWST (In-containment Refueling Water Storage Tank) boundary during an operation of Safety Depressurization and Vent System (SDVS). The test was conducted from an initial system pressure of 15.2 MPa, a steam temperature of 343.3 .deg. C, and an air mass of 3.34 lb. Following valve actuation, the pressure within the discharge line underwent pressure transient due to high pressure steam from the pressurizer and the discharged high pressure air formed air bubbles, which expanded and compressed periodically in the simulated IRWST. Air bubble oscillation was terminated within 2 s into the test. The magnitude of the pressure wave during the air clearing period was inversely proportional to the distance and very abrupt pressure spikes were observed in case the distance from the sparger holes to the submerged structure was less than 0.9 m. After the isolation valves were closed, the water in the simulated IRWST was considered to rise up to the 2.4m from the water surface in the quench tank. The amount of air mass in the piping, water temperature in the simulated IRWST, air temperature in the piping had not significant effect on the pressure loading during an air clearing period. However, the opening time of the isolation valve, steam mass flow rate, and submergence of an sparger have been shown to have great effects on the pressure loading during an air clearing period. 2 % of sparger flow area seems to be sufficient for the vacuum breaker area to mitigate the water hammering caused by abrupt water level rising during valve closure.

  16. Searching for the simplest structural units to describe the three-dimensional structure of proteins

    Science.gov (United States)

    Perczel, András; Csizmadia, Imre G.

    Ab initio computations have been carried out during the past several years on diamides of single amino acids (HCO-NHCHR-CONH2 where R=H (glycine), -CH3 (alanine), -CH(CH3)2 (valine) and -CH2OH (serine)) exploring all possible backbone and side chain conformations. Selected conformations were studied in our laboratory on threonine (R=CH(CH3)OH), cystein (R=CH2-SH) and phenyl-alanine (R=CH2-CH5H6) diamides. Tri-, tetra-, penta-, hexa- and hepta-amide systems of poly-L-alanine (H-(CONH-CHCH3-CONH)n-H 2≤n≤6) were also investigated at selected backbone conformations. All these studies confirmed the results of multidimensional conformation analyses: the jth amino acid residue in a polypeptide has a maximum of nine (9) discrete backbone conformations. These structures correspond to nine conformational centres on the 2D-Ramachandran map. On the basis of this rinding, it can be shown that the folded secondary structure of any protein with known internal coordinates, can be described in terms of these nine discrete conformation types.

  17. The Impact of the Demand for Integration in the Large Multi-Business Unit Firm on the IT Organization Structure

    Science.gov (United States)

    Larson, Eric Christopher

    2012-01-01

    Large, multi-business unit firms are decentralizing their overall corporate structures. At the same time, the structures of their IT organizations are becoming more centralized. This is contrary to current wisdom that the IT organization structure will mimic the structure of the corporation, all else being equal. Because the general business…

  18. Investigation of IrO2/Pt Electrocatalysts in Unitized Regenerative Fuel Cells

    Directory of Open Access Journals (Sweden)

    V. Baglio

    2011-01-01

    Full Text Available IrO2/Pt catalysts (at different concentrations were synthesized by incipient wetness technique and characterized by XRD, XRF, and SEM. Water electrolysis/fuel cell performances were evaluated in a 5 cm2 single cell under Unitized Regenerative Fuel Cell (URFC configuration. The IrO2/Pt composition of 14/86 showed the highest performance for water electrolysis and the lowest one as fuel cell. It is derived that for fuel cell operation an excess of Pt favours the oxygen reduction process whereas IrO2 promotes oxygen evolution. From the present results, it appears that the diffusion characteristics and the reaction rate in fuel cell mode are significantly lower than in the electrolyser mode. This requires the enhancement of the gas diffusion properties of the electrodes and the catalytic properties for cathode operation in fuel cells.

  19. In-cell infection: a novel pathway for Epstein-Barr virus infection mediated by cell-in-cell structures.

    Science.gov (United States)

    Ni, Chao; Chen, Yuhui; Zeng, Musheng; Pei, Rongjuan; Du, Yong; Tang, Linquan; Wang, Mengyi; Hu, Yazhuo; Zhu, Hanyu; He, Meifang; Wei, Xiawei; Wang, Shan; Ning, Xiangkai; Wang, Manna; Wang, Jufang; Ma, Li; Chen, Xinwen; Sun, Qiang; Tang, Hong; Wang, Ying; Wang, Xiaoning

    2015-07-01

    Epstein-Barr virus (EBV) can infect both susceptible B lymphocytes and non-susceptible epithelial cells (ECs). Viral tropism analyses have revealed two intriguing means of EBV infection, either by a receptor-mediated infection of B cells or by a cell-to-cell contact-mediated infection of non-susceptible ECs. Herein, we report a novel "in-cell infection" mechanism for EBV infection of non-susceptible ECs through the formation of cell-in-cell structures. Epithelial CNE-2 cells were invaded by EBV-infected Akata B cells to form cell-in-cell structures in vitro. Such unique cellular structures could be readily observed in the specimens of nasopharyngeal carcinoma. Importantly, the formation of cell-in-cell structures led to the autonomous activation of EBV within Akata cells and subsequent viral transmission to CNE-2 cells, as evidenced by the expression of viral genes and the presence of virion particles in CNE-2 cells. Significantly, EBV generated from in-cell infected ECs displayed altered tropism with higher infection efficacy to both B cells and ECs. In addition to CNE-2 tumor cells, cell-in-cell structure formation could also mediate EBV infection of NPEC1-Bmi1 cells, an immortalized nasopharyngeal epithelial cell line. Furthermore, efficient infection by this mechanism involved the activation of the PI3K/AKT signaling pathway. Thus, our study identified "in-cell infection" as a novel mechanism for EBV infection. Given the diversity of virus-infected cells and the prevalence of cell-in-cell structures during chronic infection, we speculate that "in-cell infection" is likely a general mechanism for EBV and other viruses to infect non-susceptible ECs.

  20. Cilia containing 9 + 2 structures grown from immortalized cells

    Institute of Scientific and Technical Information of China (English)

    Ming Zhang; Jose G Assouline

    2007-01-01

    Cilia depend on their highly differentiated structure, a 9 + 2 arrangement, to remove particles from the lung and to transport reproductive cells. Immortalized cells could potentially be of great use in cilia research. Immortalization of cells with cilia structure containing the 9 + 2 arrangement might be able to generate cell lines with such cilia structure. However, whether immortalized cells can retain such a highly differentiated structure remains unclear. Here we demonstrate that (1) using E1a gene transfection, tracheal cells are immortalized; (2) interestingly, in a gel culture the immortalized cells form spherical aggregations within which a lumen is developed; and (3) surprisingly, inside the aggregation, cilia containing a 9 + 2 arrangement grow from the cell's apical pole and protrude into the lumen. These results may influence future research in many areas such as understanding the mechanisms of cilia differentiation, cilia generation in other existing cell lines, cilia disorders, generation of other highly differentiated structures besides cilia using the gel culture,immortalization of other ciliated cells with the E1a gene, development of cilia motile function, and establishment of a research model to provide uniform ciliated cells.

  1. High-temperature superconductivity in one-unit-cell FeSe films

    Science.gov (United States)

    Wang, Ziqiao; Liu, Chaofei; Liu, Yi; Wang, Jian

    2017-04-01

    Since the dramatic enhancement of the superconducting transition temperature (T c) was reported in a one-unit-cell FeSe film grown on a SrTiO3 substrate (1-UC FeSe/STO) by molecular beam epitaxy (MBE), related research on this system has become a new frontier in condensed matter physics. In this paper, we present a brief review on this rapidly developing field, mainly focusing on the superconducting properties of 1-UC FeSe/STO. Experimental evidence for high-temperature superconductivity in 1-UC FeSe/STO, including direct evidence revealed by transport and diamagnetic measurements, as well as other evidence from scanning tunneling microscopy (STM) and angle-resolved photoemission spectroscopy (ARPES), are overviewed. The potential mechanisms of the enhanced superconductivity are also discussed. There are accumulating arguments to suggest that the strengthened Cooper pairing in 1-UC FeSe/STO originates from the interface effects, specifically the charge transfer and coupling to phonon modes in the TiO2 plane. The study of superconductivity in 1-UC FeSe/STO not only sheds new light on the mechanism of high-temperature superconductors with layered structures, but also provides an insight into the exploration of new superconductors by interface engineering.

  2. Culture of human cells in experimental units for spaceflight impacts on their behavior.

    Science.gov (United States)

    Cazzaniga, Alessandra; Moscheni, Claudia; Maier, Jeanette Am; Castiglioni, Sara

    2017-05-01

    Because space missions produce pathophysiological alterations such as cardiovascular disorders and bone demineralization which are very common on Earth, biomedical research in space is a frontier that holds important promises not only to counterbalance space-associated disorders in astronauts but also to ameliorate the health of Earth-bound population. Experiments in space are complex to design. Cells must be cultured in closed cell culture systems (from now defined experimental units (EUs)), which are biocompatible, functional, safe to minimize any potential hazard to the crew, and with a high degree of automation. Therefore, to perform experiments in orbit, it is relevant to know how closely culture in the EUs reflects cellular behavior under normal growth conditions. We compared the performances in these units of three different human cell types, which were recently space flown, i.e. bone mesenchymal stem cells, micro- and macrovascular endothelial cells. Endothelial cells are only slightly and transiently affected by culture in the EUs, whereas these devices accelerate mesenchymal stem cell reprogramming toward osteogenic differentiation, in part by increasing the amounts of reactive oxygen species. We conclude that cell culture conditions in the EUs do not exactly mimic what happens in a culture dish and that more efforts are necessary to optimize these devices for biomedical experiments in space. Impact statement Cell cultures represent valuable preclinical models to decipher pathogenic circuitries. This is true also for biomedical research in space. A lot has been learnt about cell adaptation and reaction from the experiments performed on many different cell types flown to space. Obviously, cell culture in space has to meet specific requirements for the safety of the crew and to comply with the unique environmental challenges. For these reasons, specific devices for cell culture in space have been developed. It is important to clarify whether these

  3. Applications of Fluorogens with Rotor Structures in Solar Cells.

    Science.gov (United States)

    Ong, Kok-Haw; Liu, Bin

    2017-05-29

    Solar cells are devices that convert light energy into electricity. To drive greater adoption of solar cell technologies, higher cell efficiencies and reductions in manufacturing cost are necessary. Fluorogens containing rotor structures may be helpful in addressing some of these challenges due to their unique twisted structures and photophysics. In this review, we discuss the applications of rotor-containing molecules as dyes for luminescent down-shifting layers and luminescent solar concentrators, where their aggregation-induced emission properties and large Stokes shifts are highly desirable. We also discuss the applications of molecules containing rotors in third-generation solar cell technologies, namely dye-sensitized solar cells and organic photovoltaics, where the twisted 3-dimensional rotor structures are used primarily for aggregation control. Finally, we discuss perspectives on the future role of molecules containing rotor structures in solar cell technologies.

  4. Applications of Fluorogens with Rotor Structures in Solar Cells

    Directory of Open Access Journals (Sweden)

    Kok-Haw Ong

    2017-05-01

    Full Text Available Solar cells are devices that convert light energy into electricity. To drive greater adoption of solar cell technologies, higher cell efficiencies and reductions in manufacturing cost are necessary. Fluorogens containing rotor structures may be helpful in addressing some of these challenges due to their unique twisted structures and photophysics. In this review, we discuss the applications of rotor-containing molecules as dyes for luminescent down-shifting layers and luminescent solar concentrators, where their aggregation-induced emission properties and large Stokes shifts are highly desirable. We also discuss the applications of molecules containing rotors in third-generation solar cell technologies, namely dye-sensitized solar cells and organic photovoltaics, where the twisted 3-dimensional rotor structures are used primarily for aggregation control. Finally, we discuss perspectives on the future role of molecules containing rotor structures in solar cell technologies.

  5. Structural characterization and condition for measurement statistics preservation of a unital quantum operation

    Science.gov (United States)

    Lee, Kai-Yan; Fung, Chi-Hang Fred; Chau, H. F.

    2013-05-01

    We investigate the necessary and sufficient condition for a convex cone of positive semidefinite operators to be fixed by a unital quantum operation ϕ acting on finite-dimensional quantum states. By reducing this problem to the problem of simultaneous diagonalization of the Kraus operators associated with ϕ, we can completely characterize the kinds of quantum states that are fixed by ϕ. Our work has several applications. It gives a simple proof of the structural characterization of a unital quantum operation that acts on finite-dimensional quantum states—a result not explicitly mentioned in earlier studies. It also provides a necessary and sufficient condition for determining what kind of measurement statistics is preserved by a unital quantum operation. Finally, our result clarifies and extends the work of Størmer by giving a proof of a reduction theorem on the unassisted and entanglement-assisted classical capacities, coherent information, and minimal output Renyi entropy of a unital channel acting on a finite-dimensional quantum state.

  6. Structural basis of cell-cell adhesion by NCAM

    DEFF Research Database (Denmark)

    Kasper, C; Rasmussen, H; Kastrup, Jette Sandholm Jensen;

    2000-01-01

    and learning. The 1.85 A crystal structure of the two N-terminal extracellular domains of NCAM reported here provides a structural basis for the homophilic interaction. The molecular packing of the two-domain structure reveals a cross shaped antiparallel dimer, and provides fundamental insight into trans...

  7. Capillary photoelectrode structures for photoelectrochemical and photocatalytic cells

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Xudong; Li, Zhaodong; Cai, Zhiyong; Yao, Chunhua

    2017-05-02

    Photocatalytic structures having a capillary-force based electrolyte delivery system are provided. Also provided are photoelectrochemical and photocatalytic cells incorporating the structures and methods for using the cells to generate hydrogen and/or oxygen from water. The photocatalytic structures use an electrolyte-transporting strip comprising a porous network of cellulose nanofibers to transport electrolyte from a body of the electrolyte to a porous photoelectrode or a porous photocatalytic substrate via capillary force.

  8. [Representational structure of intensive care for professionals working in mobile intensive care units].

    Science.gov (United States)

    do Nascimento, Keyla Cristiane; Gomes, Antônio Marcos Tosoli; Erdmann, Alacoque Lorenzini

    2013-02-01

    This qualitative study was performed based on the Social Representations Theory, using a structured approach. The objective was to analyze the social representations of intensive care for professionals who work in mobile intensive care units, given the determination of the central nucleus and the peripheral system. This study included the participation of 73 health care professionals from an Emergency Mobile Care Service. Data collection was performed through free association with the inducing term care for people in a life threatening situation, and analyzed using EVOC software. It is observed that a nucleus is structured in knowledge and responsibility, while contrasting elements present lexicons such as agility, care, stress, and humanization. The representational structure revealed by participants in this study refer particularly to the functionality of intensive care, distinguishing itself by the challenges and encouragements provided to anyone working in this area.

  9. Fermi surface properties of paramagnetic NpCd{sub 11} with a large unit cell

    Energy Technology Data Exchange (ETDEWEB)

    Homma, Yoshiya; Aoki, Dai; Shiokawa, Yoshinobu [Institute for Materials Research, Tohoku University, Oarai, Ibaraki 311-1313 (Japan); Haga, Yoshinori; Sakai, Hironori; Ikeda, Shugo; Yamamoto, Etsuji; Nakamura, Akio; Onuki, Yoshichika [Advanced Science Research Center, Japan Atomic Energy Agency, Tokai, Ibaraki 319-1195 (Japan); Settai, Rikio [Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043 (Japan); Takeuchi, Tetsuya [Cryogenic Center, Osaka University, Toyonaka, Osaka 560-0043 (Japan); Yamagami, Hiroshi, E-mail: yhomma@imr.tohoku.ac.jp [Department of Physics, Faculty of Science, Kyoto Sangyo University, Kyoto 603-8555 (Japan)

    2010-03-15

    We succeeded in growing a high-quality single crystal of NpCd{sub 11} with the cubic BaHg{sub 11}-type structure by the Cd-self flux method. The lattice parameter of a = 9.2968(2) A and crystallographic positions of the atoms were determined by x-ray single-crystal structure analysis. From the results of the magnetic susceptibility and specific heat experiments, this compound is found to be a 5f-localized paramagnet with the singlet ground state in the crystalline electric field (CEF) scheme. Fermi surface properties were measured using the de Haas-van Alphen (dHvA) technique. Long-period oscillations were observed in the dHvA frequency range of 9.1 x 10{sup 5} to 1.9 x 10{sup 7} Oe, indicating small cross-sectional areas of Fermi surfaces, which is consistent with a small Brillouin zone based on a large unit cell. From the results of dHvA and magnetoresistance experiments, the Fermi surface of NpCd{sub 11} is found to consist of many kinds of closed Fermi surfaces and a multiply-connected-like Fermi surface, although the result of energy band calculations based on the 5f-localized Np{sup 3+}(5f{sup 4}) configuration reveals the existence of only closed Fermi surfaces. The corresponding cyclotron effective mass is small, ranging from 0.1 to 0.7 m{sub 0}, which is consistent with a small electronic specific heat coefficient {gamma} {approx_equal} 10mJ/K{sup 2{center_dot}}mol, revealing no hybridization between the 5f electrons and conduction electrons.

  10. Predication of Plastic Flow Characteristics in Ferrite/Pearlite Steel Using a Fern Unit Cell Method

    Institute of Scientific and Technical Information of China (English)

    Hong Li; Jingtao Han; Jing Liu; Lv Zhang

    2004-01-01

    The flow stress of ferrite/pearlite steel under uni-axial tension was simulated with finite element method (FEM) by applying commercial software MARC/MENTAT. Flow stress curves of ferrite/pearlite steels were calculated based on unit cell model. The effects of volume fraction, distribution and the aspect ratio of pearlite on tensile properties have been investigated.

  11. Mitigation of Unwanted Forward Narrow-band Radiation from PCBs with a Metamaterial Unit Cell

    DEFF Research Database (Denmark)

    Ruaro, Andrea; Thaysen, Jesper; Jakobsen, Kaj Bjarne

    2013-01-01

    Mitigation of EMI from a PCB is obtained through the use of a metamaterial unit cell. The focus is on the reduction of narrow-band radiation in the forward hemisphere when the resonant element is etched on a layer located between the source of radiation and the ground plane. As opposed to previou...

  12. Recovery Act. Solid Oxide Fuel Cell Diesel Auxilliary Power Unit Demonstration

    Energy Technology Data Exchange (ETDEWEB)

    Geiger, Gail E. [Delphi Automotive Systems, LLC., Gillingham (United Kingdom)

    2013-09-30

    Solid Oxide Fuel Cell Diesel Auxilliary Power Unit Demonstration Project. Summarizing development of Delphi’s next generation SOFC system as the core power plant to prove the viability of the market opportunity for a 3-5 kW diesel SOFC system. Report includes test and demonstration results from testing the diesel APU in a high visibility fleet customer vehicle application.

  13. Question 7: the first units of life were not simple cells.

    Science.gov (United States)

    Norris, Vic; Hunding, Axel; Kepes, Francois; Lancet, Doron; Minsky, Abraham; Raine, Derek; Root-Bernstein, Robert; Sriram, K

    2007-10-01

    Five common assumptions about the first cells are challenged by the pre-biotic ecology model and are replaced by the following propositions: firstly, early cells were more complex, more varied and had a greater diversity of constituents than modern cells; secondly, the complexity of a cell is not related to the number of genes it contains, indeed, modern bacteria are as complex as eukaryotes; thirdly, the unit of early life was an 'ecosystem' rather than a 'cell'; fourthly, the early cell needed no genes at all; fifthly, early life depended on non-covalent associations and on catalysts that were not confined to specific reactions. We present here the outlines of a theory that connects findings about modern bacteria with speculations about their origins.

  14. Electrochemical cell structure including an ionomeric barrier

    Energy Technology Data Exchange (ETDEWEB)

    Lambert, Timothy N.; Hibbs, Michael

    2017-06-20

    An apparatus includes an electrochemical half-cell comprising: an electrolyte, an anode; and an ionomeric barrier positioned between the electrolyte and the anode. The anode may comprise a multi-electron vanadium phosphorous alloy, such as VP.sub.x, wherein x is 1-5. The electrochemical half-cell is configured to oxidize the vanadium and phosphorous alloy to release electrons. A method of mitigating corrosion in an electrochemical cell includes disposing an ionomeric barrier in a path of electrolyte or ion flow to an anode and mitigating anion accumulation on the surface of the anode.

  15. Prokaryotic cells: structural organisation of the cytoskeleton and organelles

    OpenAIRE

    Wanderley de Souza

    2012-01-01

    For many years, prokaryotic cells were distinguished from eukaryotic cells based on the simplicity of their cytoplasm, in which the presence of organelles and cytoskeletal structures had not been discovered. Based on current knowledge, this review describes the complex components of the prokaryotic cell cytoskeleton, including (i) tubulin homologues composed of FtsZ, BtuA, BtuB and several associated proteins, which play a fundamental role in cell division, (ii) actin-like homologues, such as...

  16. Understanding the Functional Central Limit Theorems with Some Applications to Unit Root Testing with Structural Change

    Directory of Open Access Journals (Sweden)

    Juan Carlos Aquino

    2013-06-01

    Full Text Available The application of different unit root statistics is by now a standard practice in empirical work. Even when it is a practical issue, these statistics have complex nonstandard distributions depending on functionals of certain stochastic processes, and their derivations represent a barrier even for many theoretical econometricians. These derivations are based on rigorous and fundamental statistical tools which are not (very well known by standard econometricians. This paper aims to fill this gap by explaining in a simple way one of these fundamental tools: namely, the Functional Central Limit Theorem. To this end, this paper analyzes the foundations and applicability of two versions of the Functional Central Limit Theorem within the framework of a unit root with a structural break. Initial attention is focused on the probabilistic structure of the time series to be considered. Thereafter, attention is focused on the asymptotic theory for nonstationary time series proposed by Phillips (1987a, which is applied by Perron (1989 to study the effects of an (assumed exogenous structural break on the power of the augmented Dickey-Fuller test and by Zivot and Andrews (1992 to criticize the exogeneity assumption and propose a method for estimating an endogenous breakpoint. A systematic method for dealing with efficiency issues is introduced by Perron and Rodriguez (2003, which extends the Generalized Least Squares detrending approach due to Elliot et al. (1996. An empirical application is provided.

  17. A heated vapor cell unit for dichroic atomic vapor laser lock in atomic rubidium.

    Science.gov (United States)

    McCarron, Daniel J; Hughes, Ifan G; Tierney, Patrick; Cornish, Simon L

    2007-09-01

    The design and performance of a compact heated vapor cell unit for realizing a dichroic atomic vapor laser lock (DAVLL) for the D(2) transitions in atomic rubidium is described. A 5 cm long vapor cell is placed in a double-solenoid arrangement to produce the required magnetic field; the heat from the solenoid is used to increase the vapor pressure and correspondingly the DAVLL signal. We have characterized experimentally the dependence of important features of the DAVLL signal on magnetic field and cell temperature. For the weaker transitions both the amplitude and gradient of the signal are increased by an order of magnitude.

  18. Quasi bound states in the continuum with few unit cells of photonic crystal slab

    DEFF Research Database (Denmark)

    Taghizadeh, Alireza; Chung, Il-Sug

    2017-01-01

    Bound states in the continuum (BICs) in photonic crystal slabs represent the resonances with an infinite quality (Q)-factor, occurring above the light line for an infinitely periodic structure. We show that a set of BICs can turn into quasi-BICs with a very high Q-factor even for two or three unit...

  19. A Micromechanical Unit Cell Model of 2 × 2 Twill Woven Fabric Textile Composite for Multi Scale Analysis

    Science.gov (United States)

    Dixit, A.; Mali, H. S.; Misra, R. K.

    2014-04-01

    Woven fabric based composite materials are being considered for potential structural applications in automotive and aircraft industries due to their better out of plane strength, stiffness and toughness properties than ordinary composite laminates. This paper presents the micromechanical unit cell model of 2 × 2 twill woven fabric textile composite for the estimation of in-plane elastic properties. Modelling of unit cell and its analysis for this new model is developed by using open source coded tool TexGen and finite element software, ABAQUS® respectively. The predicted values are in good agreement with the experimental results reported in literature. To ascertain the effectiveness of the developed model parametric studies have also been conducted on the predicted elastic properties in order to investigate the effects of various geometric parameters such as yarn spacing, fabric thickness, yarn width and fibre volume fraction. The scope of altering weave pattern and yarn characteristics is facilitated in this developed model. Further this model can be implemented for the multi-scale micro/macro-mechanical analysis for the calculation of strength and stiffness of laminates structure made of 2 × 2 twill composite.

  20. Structural basis of Prospero-DNA interaction: implications for transcription regulation in developing cells.

    Science.gov (United States)

    Yousef, Mohammad S; Matthews, Brian W

    2005-04-01

    The crystal structure of a complex between the novel homeodomain of the neural transcription factor Prospero and DNA shows that the invariant residues Lys1290, Asn1294, and Asp1297 make specific contacts with the noncanonical DNA binding site. The overall structure includes the homeodomain and the adjacent Prospero domain and confirms that they act as a single structural unit, a Homeo-Prospero domain. The Prospero domain facilitates the proper alignment of the protein on the DNA. Knowledge of the structure reconciles two different DNA sequences that have been proposed as transcriptional targets for Prospero. As in the apo structure, the C terminus of the Prospero domain shields a short helix within the homeodomain that includes a nuclear export signal (NES). The structural results suggest that exposure of the NES is not coupled directly to DNA binding. We propose a DNA recognition mechanism specific to Prospero-type homeodomains in developing cells.

  1. A Single-Unit Design Structure and Gender Differences in the Swimming World Championships

    OpenAIRE

    2014-01-01

    Four 50 meter male/female finals - the freestyle, butterfly, breaststroke, and backstroke - swum during individual events at the Swimming World Championships (SWCs) can be defined in four clusters. The aim of the present study was to use a single-unit design structure, in which the swimmer was defined at only one scale, to evaluate gender differences in start reaction times among elite swimmers in 50 m events. The top six male and female swimmers in the finals of four swimming stroke final ev...

  2. A switchable pH-differential unitized regenerative fuel cell with high performance

    Science.gov (United States)

    Lu, Xu; Xuan, Jin; Leung, Dennis Y. C.; Zou, Haiyang; Li, Jiantao; Wang, Hailiang; Wang, Huizhi

    2016-05-01

    Regenerative fuel cells are a potential candidate for future energy storage, but their applications are limited by the high cost and poor round-trip efficiency. Here we present a switchable pH-differential unitized regenerative fuel cell capable of addressing both the obstacles. Relying on a membraneless laminar flow-based design, pH environments in the cell are optimized independently for different electrode reactions and are switchable together with the cell process to ensure always favorable thermodynamics for each electrode reaction. Benefiting from the thermodynamic advantages of the switchable pH-differential arrangement, the cell allows water electrolysis at a voltage of 0.57 V, and a fuel cell open circuit voltage of 1.89 V, rendering round-trip efficiencies up to 74%. Under room conditions, operating the cell in fuel cell mode yields a power density of 1.3 W cm-2, which is the highest performance to date for laminar flow-based cells and is comparable to state-of-the-art polymer electrolyte membrane fuel cells.

  3. A fuel cell energy storage system concept for the Space Station Freedom Extravehicular Mobility Unit

    Science.gov (United States)

    Adlhart, Otto J.; Rosso, Matthew J., Jr.; Marmolejo, Jose

    1989-01-01

    An update is given on work to design and build a Fuel Cell Energy Storage System (FCESS) bench-tested unit for the Space Station Freedom Extravehicular Mobility Unit (EMU). Fueled by oxygen and hydride-stored hydrogen, the FCESS is being considered as an alternative to the EMU zinc-silver oxide battery. Superior cycle life and quick recharge are the main attributes of FCESS. The design and performance of a nonventing, 28 V, 34 Ahr system with 7 amp rating are discussed.

  4. Single-unit transfusions and hemoglobin trigger: relative impact on red cell utilization.

    Science.gov (United States)

    Yang, William W; Thakkar, Rajiv N; Gehrie, Eric A; Chen, Weiyun; Frank, Steven M

    2017-05-01

    Patient blood management (PBM) programs can reduce unnecessary transfusions, but the optimal methods used to achieve this effect are unclear. We tested the hypothesis that encouraging single-unit red blood cell (RBC) transfusions in stable patients would have a greater impact on blood use than compliance with a specific hemoglobin (Hb) transfusion trigger alone. We analyzed blood utilization data at three community hospitals without previous PBM efforts before and after implementing a PBM program. Data were analyzed at monthly intervals to determine the relative impact of a "Why give 2 when 1 will do?" campaign promoting single-unit RBC transfusions and simultaneous efforts to promote evidence-based Hb triggers of 7 or 8 g/dL. Univariate and multivariate analyses were used to identify independent effects of these two interventions on overall RBC utilization. Univariate analysis revealed that both the increase in single-unit transfusions (from 38.0% to 70.9%; p utilization. Multivariate analysis showed that the increase in single-unit transfusions was an independent predictor of decreased RBC utilization, but the Hb triggers of both 7 and 8 g/dL were not. Overall, our PBM efforts decreased RBC utilization from 0.254 to 0.185 units/patient (27.2%) across all three hospitals (p = 0.0009). A campaign promoting single-unit RBC transfusions had a greater impact on RBC utilization than did encouraging a restrictive transfusion trigger. © 2016 AABB.

  5. The Daniell Cell, Ohm's Law and the Emergence of the International System of Units

    CERN Document Server

    Jayson, Joel S

    2015-01-01

    Telegraphy originated in the 1830s and 40s and flourished in the following decades, but with a patchwork of electrical standards. Electromotive force was for the most part measured in units of the predominant Daniell cell. Each company had their own resistance standard. In 1862 the British Association for the Advancement of Science formed a committee to address this situation. By 1873 they had given definition to the electromagnetic system of units (emu) and defined the practical units of the ohm as ${10}^9$ emu units of resistance and the volt as ${10}^8$ emu units of electromotive force. These recommendations were ratified and expanded upon in a series of international congresses held between 1881 and 1904. A proposal by Giovanni Giorgi in 1901 took advantage of a coincidence between the conversion of the units of energy in the emu system (the erg) and in the practical system (the joule) in that the same conversion factor existed between the cgs based emu system and a theretofore undefined MKS system. By in...

  6. Three Dimensional Structure of the Mars North Polar Basal Unit from MARSIS data

    Science.gov (United States)

    Frigeri, A.; Orosei, R.; Cartacci, M.; Cicchetti, A.; Mitri, G.; Giuppi, S.; Noschese, R.; Picardi, G.; Plaut, J.

    2012-04-01

    Mars Advanced Radar for Subsurface and Ionospheric Sounding (MARSIS) is an orbital subsurface sounder aboard ESA's Mars Express spacecraft . It transmits a low-frequency radar pulse that is capable of penetrating below the surface, and is reflected by subsurface dielectric discontinuities. MARSIS has been used to probe both the south and the north polar caps of Mars, revealing their thickness and structure. We report on the results of a campaign of observations of the north polar ice cap of Mars that took place between May and December 2011 in uniquely favorable conditions and produced data of unprecedented quality. The focus of this work is the so-called Basal Unit, a dark, ice-rich, complexely layered geologic unit lying stratigraphically between the polar layered deposits and the Vastitas Borealis Formation, and extending beneath most of Planum Boreum and Olympia Planitia. The objective of this work is the to study the full three dimensional structure of the Northern Polar Deposit and in particular of the Basal Unit (BU). It was recently found that the BU consists of two markedly different units, called the Rupes Tenuis unit and the Planum Boreum cavi unit. The Rupes Tenuis unit appears to be older, horizontally layered, and lacking erosional contacts. It has been thus interpreted as the result of precipitation and cold-trapping of dust-laden volatiles. The Planum Boreum cavi unit displays cross-bedding, indicating dune accumulation. Bright layers within it are interpreted as being made of ice-cemented dust, while dark layers should consist of weathered basalt fines. It seems likely that, in places, the Planum Boreum cavi unit rests directly on the Vastitas Borealis, without the Rupes Tenuis unit in between. Because the two units in the BU have formed much earlier than the north polar layered deposits, and at some interval from each other, they bear evidence of past climatic conditions that were very different from present, so that they "could potentially be a

  7. Crystalline structures in human pancreatic beta cell adenoma.

    Science.gov (United States)

    Mori, H; Kawai, T; Tanaka, T; Fujii, M; Takahashi, M; Miyashita, T

    1978-05-01

    An electron microscopic observation on a pancreatic tumor removed from a 34-year-old woman revealed the fine structural morphology of a functional beta cell adenoma. Characteristic PAS positive crystalline structures were frequently observed in the cytoplasm of the tumor cells. They were not bounded by a membrane and had a rectangular or irregular hexagonal shape. Highly regular patterns were seen as such as lattice or honeycomb and parallel ripple structures. They are similar to the Reinke's crystal or crystalline structures reported in human hepatocytes suffering from several different diseases and considered as a protein-carbohydrate complex. Occasionally, small paracrystalline structures appeared to indicate an immature type of these structures in the opaque fine fibrillar mass. Crystalline or paracrystalline structures were not detected in the normal pancreatic tissue removed with the tumor from the patient.

  8. Institutional and Organizational Structure of the Federal Procurement System of the United States

    Directory of Open Access Journals (Sweden)

    Vovchenko Natalya Gennadyevna

    2015-09-01

    Full Text Available The paper deals with the role of the Federal procurement system of the United States as a regulatory tool of the U.S. economy. The scope of research is focused on organizational and institutional aspects of forming and developing the U.S. Federal procurement system. The main purpose of the paper is to study up-to-date mechanism of government acquisition in the United States and to consider all its structural elements taken in conjunction with each other, such as the President, the Office of Management and Budget (OMB, the Office of Federal Procurement Policy (OFPP, the General Services Administration (GSA, other executive and regulatory agencies. The methodological background of the research is based on normative, system-wide, statistical and complex approaches to the study of structural elements of the U.S. Federal procurement system. The theoretical and practical material of the present research can be used in teaching and learning activities at economic faculties, for instance, in the course of lectures on government contacting and public procurement management. It also can be used in training and advanced training of specialists who draft public procurement regulations in the Russian Federation. The statutory regulation of the U.S. Federal procurement system constitutes an organizational framework of executive agencies, their functions and responsibilities, specifics of government control over contract performance, competition requirements and contracting methods. The paper considered interrelated components of the U.S. Federal procurement system, which operates in furtherance of efficient utilization of Federal budget.

  9. Towards understanding cellular structure biology: In-cell NMR.

    Science.gov (United States)

    Rahman, Safikur; Byun, Younhwa; Hassan, Md Imtaiyaz; Kim, Jihoe; Kumar, Vijay

    2017-05-01

    To watch biological macromolecules perform their functions inside the living cells is the dream of any biologists. In-cell nuclear magnetic resonance is a branch of biomolecular NMR spectroscopy that can be used to observe the structures, interactions and dynamics of these molecules in the living cells at atomic level. In principle, in-cell NMR can be applied to different cellular systems to achieve biologically relevant structural and functional information. In this review, we summarize the existing approaches in this field and discuss its applications in protein interactions, folding, stability and post-translational modifications. We hope this review will emphasize the effectiveness of in-cell NMR for studies of intricate biological processes and for structural analysis in cellular environments. Copyright © 2017 Elsevier B.V. All rights reserved.

  10. Regulations in the United States for cell transplantation clinical trials in neurological diseases

    Institute of Scientific and Technical Information of China (English)

    He Zhu; Yuanqing Tan; Qi Gu; Weifang Han; Zhongwen Li; Jason S Meyer; Baoyang Hu

    2015-01-01

    Objective: This study aimed to use a systematic approach to evaluate the current utilization, safety, and effectiveness of cell therapies for neurological diseases in human. And review the present regulations, considering United States (US) as a representative country, for cell transplantation in neurological disease and discuss the challenges facing the field of neurology in the coming decades. Methods:A detailed search was performed in systematic literature reviews of cellular‐based therapies in neurological diseases, using PubMed, web of science, and clinical trials. Regulations of cell therapy products used for clinical trials were searched from the Food and Drug Administration (FDA) and the National Institutes of Health (NIH). Results: Seven most common types of cell therapies for neurological diseases have been reported to be relatively safe with varying degrees of neurological recovery. And a series of regulations in US for cellular therapy was summarized including preclinical evaluations, sourcing material, stem cell manufacturing and characterization, cell therapy product, and clinical trials. Conclusions:Stem cell‐based therapy holds great promise for a cure of such diseases and will value a growing population of patients. However, regulatory permitting activity of the US in the sphere of stem cells, technologies of regenerative medicine and substitutive cell therapy are selective, theoretical and does not fit the existing norm and rules. Compiled well‐defined regulations to guide the application of stem cell products for clinical trials should be formulated.

  11. Influence of laminar flow on preorientation of coal tar pitch structural units: Raman microspectroscopic study

    Science.gov (United States)

    Urban, O.; Jehlička, J.; Pokorný, J.; Rouzaud, J. N.

    2003-08-01

    In order to estimate the role of laminar flow of viscous, aromatic matter of carbonaceous precursor on microtextural preorientation in pregraphitization stage, we performed experiments with coal tar pitch (CTP). The principal hypothesis of preorientation of basic structural units (BSUs) in the case of laminar flow (pressure impregnation of CTP into porous matrix) and secondary release of volatiles during carbonization were studied. Glass microplates, planar porous medium with average distance between single microplates 5 μm were used as suitable porous matrix. Samples of CTP were carbonized up to 2500 °C. Optical microscopy reveals large flow domains in the sample of cokes carbonized between glass microplates. Raman microspectroscopy and high resolution transmission electron microscopy (HRTEM) show that at nanometric scale, the samples do not support the proposed hypotheses. With increasing temperature of pyrolysis, the graphitization of CTP impregnated into porous matrix proceeds to lower degree of structural ordering in comparison with single pyrolyzed CTP. This is explained by the release of volatile matter during carbonization in geometrically restricted spaces. More evident structural changes were discovered with the sample of single coke, where parts of fine grain mosaics, relicts of 'so called QI parts', reveal higher structural organization, in comparison with large and prolonged flow domains, similar to flow domains of cokes from microplates.

  12. Molecular structure and biological function of proliferating cell nuclear antigen

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Proliferating cell nuclear antigen (PCNA) is the core component of replication complex in eukaryote.As a processive factor of DNA polymerase delta, PCNA coordinates the replication process by interacting with various replication proteins. PCNA appears to play an essential role in many cell events, such as DNA damage repair, cell cycle regulation, and apoptosis, through the coordination or organization of different partners. PCNA is an essential factor in cell proliferation, and has clinical significance in tumor research. In this article we review the functional structure of PCNA, which acts as a function switch in different cell events.

  13. Simulation of interdigitated back contact solar cell with trench structure

    Science.gov (United States)

    Kim, Soo Min; Chun, Seungju; Kang, Min Gu; Song, Hee-Eun; Lee, Jong-Han; Boo, Hyunpil; Bae, Soohyun; Kang, Yoonmook; Lee, Hae-Seok; Kim, Donghwan

    2015-02-01

    We performed two-dimensional technology computer-aided design simulations for interdigitated back contact (IBC) solar cells with rear trench structures (TS), denoted here as TS-IBC solar cells. First, we calculated a reference simulation model for conventional IBC solar cells. We then assumed a trench structure at the rear surface of the IBC solar cell. For this structure, we analyzed solar cell performance as a function of various trench depths and type. It was found that emitter trench formation affects minority carrier collection, such that the short-circuit current density increases with increasing trench depth. However, the back-surface field (BSF) trench exhibited poor minority carrier collection, which reduced the conversion efficiency of the TS-IBC solar cells. It was also found that for the same trench depth (30 μm), the difference in conversion efficiencies of an IBC solar cell with an emitter trench and that with a BSF trench was 0.6%. We are thus convinced that the emitter trench structure is more important than the BSF trench structure.

  14. Bringing some photonic structures for solar cells to the fore.

    Science.gov (United States)

    Escoubas, Ludovic; Simon, Jean-Jacques; Torchio, Philippe; Duché, David; Vedraine, Sylvain; Vervisch, Wilfried; Le Rouzo, Judikaël; Flory, François; Rivière, Guillaume; Yeabiyo, Gizachew; Derbal, Hassina

    2011-03-20

    A review on the use of photonic structures enabling a better absorption of solar radiation within solar cells is proposed. Specific geometric configurations, such as folded solar cells or fiber-based architectures, are shown to be promising solutions to reach better light absorption. Electromagnetic optimization of thin-film solar cells and the use of angular thin-film filters, proposed by several research groups, also provide solutions to better concentrate solar radiation within the active layers of solar cells. Finally, results on "photonized" solar cells comprising gratings or more advanced photonic components, such as photonic crystals or plasmonic structures, and their effects on light-matter interaction in solar cells are highlighted.

  15. Bifacial cells of p/sup +/in/sup +/ structure

    Energy Technology Data Exchange (ETDEWEB)

    Araujo, G.L.; Calleja, M.J.; Castano, J.; Lopez Romero, S.; Lugue, A.; Sanchez, E.

    1982-09-01

    Bifacial cells of p/sup +/in/sup +/ structure are intrinsically very symmetric as shown both, theoretically and experimentally. Their bifacial behaviour is analyzed and compared to that of p/sup +/nn/sup +/ cells in low injection for low values of the diffusion length. Cells of p/sup +/in/sup +/ structure are anticipated to present better bifacial behaviour for all the ranges of L. An approximate two-exponential formula is given to account for the behaviour of p/sup +/in+ cells and the values of the parameters in this formula are measured in typical cases. The validity of superposition is studied, leading to the conclusion that it is not theoretically satisfied. The results of a pilot fabrication of p/sup +/in/sup +/ bifacial cells are given and compared to those of low injection bifacial cells.

  16. A study of structural differences between liver cancer cells and normal liver cells using FTIR spectroscopy

    Science.gov (United States)

    Sheng, Daping; Xu, Fangcheng; Yu, Qiang; Fang, Tingting; Xia, Junjun; Li, Seruo; Wang, Xin

    2015-11-01

    Since liver cancer seriously threatens human health, it is very urgent to explore an effective method for diagnosing liver cancer early. In this study, we investigated the structure differences of IR spectra between neoplastic liver cells and normal liver cells. The major differences of absorption bands were observed between liver cancer cells and normal liver cells, the values of A2955/A2921, A1744/A1082, A1640/A1535, H1121/H1020 might be potentially useful factors for distinguishing liver cancer cells from normal liver cells. Curve fitting also provided some important information on structural differences between malignant and normal liver cancer cells. Furthermore, IR spectra combined with hierarchical cluster analysis could make a distinction between liver cancer cells and normal liver cells. The present results provided enough cell basis for diagnosis of liver cancer by FTIR spectroscopy, suggesting FTIR spectroscopy may be a potentially useful tool for liver cancer diagnosis.

  17. Fuel cell collaboration in the United States. Follow up report to the Danish Partnership for Hydrogen and Fuel Cells

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2013-01-15

    Fuel cell technology continues to grow in the United States, with strong sales in stationary applications and early markets such as data centers, materials handling equipment, and telecommunications sites. New fuel cell customers include Fortune 500 companies Apple, eBay, Coca-Cola, and Walmart, who will use fuel cells to provide reliable power to data centers, stores, and facilities. Some are purchasing multi-megawatt (MW) systems, including three of the largest non-utility purchases of stationary fuel cells in the world by AT and T, Apple and eBay - 17 MW, 10 MW and 6 MW respectively. Others are replacing fleets of battery forklifts with fuel cells. Sysco, the food distributor, has more than 700 fuel cell-powered forklifts operating at seven facilities, with more on order. Mega-retailer Walmart now operates more than 500 fuel cell forklifts at three warehouses, including a freezer facility. Although federal government budget reduction efforts are impacting a wide range of departments and programs, fuel cell and hydrogen technology continues to be funded, albeit at a lower level than in past years. The Department of Energy (DOE) is currently funding fuel cell and hydrogen R and D and has nearly 300 ongoing projects at companies, national labs, and universities/institutes universities. The American Recovery and Reinvestment Act (ARRA) of 2009 and DOE's Market Transformation efforts have acted as a government ''catalyst'' for market success of emerging technologies. Early market deployments of about 1,400 fuel cells under the ARRA have led to more than 5,000 additional fuel cell purchases by industry with no DOE funding. In addition, interest in Congress remains high. Senators Richard Blumenthal (D-CT), Chris Coons (D-DE), Lindsey Graham (R-SC) and John Hoeven (R-ND) re-launched the bipartisan Senate Fuel Cell and Hydrogen Caucus in August 2012 to promote the continued development and commercialization of hydrogen and fuel cell technologies

  18. Study on Unit Cell Models and the Effective Thermal Conductivities of Silica Aerogel.

    Science.gov (United States)

    Liu, He; Li, Zeng-Yao; Zhao, Xin-Peng; Tao, Wen-Quan

    2015-04-01

    In this paper, two modified unit cell models, truncated octahedron and cubic array of intersecting square rods with 45-degree rotation, are developed in consideration of the tortuous path of heat conduction in solid skeleton of silica aerogel. The heat conduction is analyzed for each model and the expressions of effective thermal conductivity of the modified unit cell models are derived. Considering the random microstructure of silica aerogel, the probability model is presented. We also discuss the effect of the thermal conductivity of aerogel backbone. The effective thermal conductivities calculated by the proposed probability model are in good agreement with available experimental data when the density of the aerogel is 110 kg/m3.

  19. Hydrothermal syntheses and characterization of uranyl tungstates with electro-neutral structural units

    Energy Technology Data Exchange (ETDEWEB)

    Balboni, Enrica; Burns, Peter C. [Univ. of Notre Dame, IN (United States). Dept. of Civil and Enviromental Engineering and Earth Sciences; Univ. of Notre Dame, IN (United States). Dept. of Chemistry and Biochemistry

    2015-11-01

    Two uranyl tungstates, (UO{sub 2})(W{sub 2}O{sub 7})(H{sub 2}O){sub 3} (1) and (UO{sub 2}){sub 3}(W{sub 2}O{sub 8})F{sub 2}(H{sub 2}O){sub 3} (2), were synthesized under hydrothermal conditions at 220 C and were structurally, chemically, and spectroscopically characterized. 1 Crystallizes in space group Pbcm, a = 6.673(5) Aa, b = 12.601(11) Aa, c = 11.552 Aa; 2 is in C2/m, a = 13.648(1) Aa, b = 16.852(1) Aa, c = 9.832(1) Aa, β = 125.980(1) {sup circle}. In 1 the U(VI) cations are present as (UO{sub 2}){sup 2+} uranyl ions that are coordinated by five oxygen atoms to give pentagonal bipyramids. These share two edges with two tungstate octahedra and single vertices with four additional octahedra, resulting in a sheet with the iriginite-type anion topology. Only water molecules are located in the interlayer. The structural units of 2 consist of (UO{sub 2}){sup 2+} uranyl oxy-fluoride pentagonal bipyramids present as either [UO{sub 2}F{sub 2}O{sub 3}]{sup -6} or [UO{sub 2}FO{sub 4}]{sup -5}, and strongly distorted tungstate octahedra. The linkage of uranyl pentagonal bipyramids and tungstate octahedra gives a unique sheet anion topology consisting of pentagons, squares and triangles. In 2, the uranyl tungstates sheets are connected into a novel electro-neutral three-dimensional framework through dimers of uranyl pentagonal bipyramids. These dimers connecting the sheets share an edge defined by F anions. 2 is the first example of a uranyl tungstate oxy-fluoride, and 1 and 2 are rare examples of uranyl compounds containing electro-neutral structural units.

  20. Structures and properties of porous coordination polymers based on lanthanide carboxylate building units.

    Science.gov (United States)

    Han, Yinfeng; Li, Xiaoyan; Li, Liqing; Ma, Chunlin; Shen, Zhen; Song, You; You, Xiaozeng

    2010-12-06

    A series of 3-D lanthanide porous coordination polymers, [Ln(6)(BDC)(9)(DMF)(6)(H(2)O)(3)·3DMF](n) [Ln = La, 1; Ce, 2; Nd, 3], [Ln(2)(BDC)(3)(DMF)(2)(H(2)O)(2)](n) [Ln = Y, 4; Dy, 5; Eu, 6], [Ln(2)(ADB)(3)(DMSO)(4)·6DMSO·8H(2)O](n) [Ln = Ce, 7; Sm, 8; Eu, 9; Gd, 10], {[Ce(3)(ADB)(3)(HADB)(3)]·30DMSO·29H(2)O}(n) (11), and [Ce(2)(ADB)(3)(H(2)O)(3)](n) (12) (H(2)BDC = benzene-1,4-dicarboxylic acid and H(2)ADB = 4,4'-azodibenzoic acid), have been synthesized and characterized. In 1-3, the adjacent Ln(III) ions are intraconnected to form 1-D metal-carboxylate oxygen chain-shaped building units, [Ln(4)(CO(2))(12)](n), that constructed a 3-D framework with 4 × 7 Å rhombic channels. In 4-6, the dimeric Ln(III) ions are interlinked to yield scaffolds with 3-D interconnecting tunnels. Compounds 7-10 are all 3-D interpenetrating structures with the CaB6-type topology structure. Compound 11 is constructed by ADB spacers and trinulcear Ce nodes with a NaCl-type topology structure and a 1.9-nm open channel system. In 12, the adjacent Ce(III) ions are intraconnected to form 1-D metal-carboxylate oxygen chain-shaped building units, [Ln(4)(CO(2))(12)](n), and give rise to a 3-D framework. Moreover, 6 exhibits characteristic red luminescence properties of Eu(III) complexes. The magnetic susceptibilities, over a temperature range of 1.8-300 K, of 3, 6, and 7 have also been investigated; the results show paramagnetic properties.

  1. On the Performance of Hybrid PV/Unitized Regenerative Fuel Cell System in the Tropics

    Directory of Open Access Journals (Sweden)

    Salwan Dihrab

    2012-01-01

    Full Text Available Solar hydrogen system is a unique power system that can meet the power requirements for future energy demands. Such a system uses the hydrogen as the energy carrier, which produces energy through the electrolyzer with assistance of the power from the PV during the sunny hours, and then uses stored hydrogen to produce energy through the fuel cell after sunset or on cloudy days. The current study has used premanufactured unitized regenerative fuel cells in which the electrolyzer and the fuel cell function within one cell at different modes. The system components were modeled and the one-day real operational and simulated data has been presented and compared. The measured results showed the ability of the system to meet the proposed load, and the total efficiency was about 4.5%.

  2. Dielectric Behavior of Low Microwave Loss Unit Cell for All Dielectric Metamaterial

    Directory of Open Access Journals (Sweden)

    Tianhuan Luo

    2015-01-01

    Full Text Available With a deep study of the metamaterial, its unit cells have been widely extended from metals to dielectrics. The dielectric based unit cells attract much attention because of the advantage of easy preparation, tunability, and higher frequency response, and so forth. Using the conventional solid state method, we prepared a kind of incipient ferroelectrics (calcium titanate, CaTiO3 with higher microwave permittivity and lower loss, which can be successfully used to construct metamaterials. The temperature and frequency dependence of dielectric constant are also measured under different sintering temperatures. The dielectric spectra showed a slight permittivity decrease with the increase of temperature and exhibited a loss of 0.0005, combined with a higher microwave dielectric constant of ~167 and quality factor Q of 2049. Therefore, CaTiO3 is a kind of versatile and potential metamaterial unit cell. The permittivity of CaTiO3 at higher microwave frequency was also examined in the rectangular waveguide and we got the permittivity of 165, creating a new method to test permittivity at higher microwave frequency.

  3. Design, Analysis and Fabrication of Secondary Structural Components for the Habitat Demonstration Unit-Deep Space Habitat

    Science.gov (United States)

    Smith, Russell W.; Langford, William M.

    2012-01-01

    In support of NASA s Habitat Demonstration Unit - Deep Space Habitat Prototype, a number of evolved structural sections were designed, fabricated, analyzed and installed in the 5 meter diameter prototype. The hardware consisted of three principal structural sections, and included the development of novel fastener insert concepts. The articles developed consisted of: 1) 1/8th of the primary flooring section, 2) an inner radius floor beam support which interfaced with, and supported (1), 3) two upper hatch section prototypes, and 4) novel insert designs for mechanical fastener attachments. Advanced manufacturing approaches were utilized in the fabrication of the components. The structural components were developed using current commercial aircraft constructions as a baseline (for both the flooring components and their associated mechanical fastener inserts). The structural sections utilized honeycomb sandwich panels. The core section consisted of 1/8th inch cell size Nomex, at 9 lbs/cu ft, and which was 0.66 inches thick. The facesheets had 3 plys each, with a thickness of 0.010 inches per ply, made from woven E-glass with epoxy reinforcement. Analysis activities consisted of both analytical models, as well as initial closed form calculations. Testing was conducted to help verify analysis model inputs, as well as to facilitate correlation between testing and analysis. Test activities consisted of both 4 point bending tests as well as compressive core crush sequences. This paper presents an overview of this activity, and discusses issues encountered during the various phases of the applied research effort, and its relevance to future space based habitats.

  4. Cell membrane fluid-mosaic structure and cancer metastasis.

    Science.gov (United States)

    Nicolson, Garth L

    2015-04-01

    Cancer cells are surrounded by a fluid-mosaic membrane that provides a highly dynamic structural barrier with the microenvironment, communication filter and transport, receptor and enzyme platform. This structure forms because of the physical properties of its constituents, which can move laterally and selectively within the membrane plane and associate with similar or different constituents, forming specific, functional domains. Over the years, data have accumulated on the amounts, structures, and mobilities of membrane constituents after transformation and during progression and metastasis. More recent information has shown the importance of specialized membrane domains, such as lipid rafts, protein-lipid complexes, receptor complexes, invadopodia, and other cellular structures in the malignant process. In describing the macrostructure and dynamics of plasma membranes, membrane-associated cytoskeletal structures and extracellular matrix are also important, constraining the motion of membrane components and acting as traction points for cell motility. These associations may be altered in malignant cells, and probably also in surrounding normal cells, promoting invasion and metastatic colonization. In addition, components can be released from cells as secretory molecules, enzymes, receptors, large macromolecular complexes, membrane vesicles, and exosomes that can modify the microenvironment, provide specific cross-talk, and facilitate invasion, survival, and growth of malignant cells.

  5. Scattering pulse of label free fine structure cells to determine the size scale of scattering structures

    Science.gov (United States)

    Zhang, Lu; Chen, Xingyu; Zhang, Zhenxi; Chen, Wei; Zhao, Hong; Zhao, Xin; Li, Kaixing; Yuan, Li

    2016-04-01

    Scattering pulse is sensitive to the morphology and components of each single label-free cell. The most direct detection result, label free cell's scattering pulse is studied in this paper as a novel trait to recognize large malignant cells from small normal cells. A set of intrinsic scattering pulse calculation method is figured out, which combines both hydraulic focusing theory and small particle's scattering principle. Based on the scattering detection angle ranges of widely used flow cytometry, the scattering pulses formed by cell scattering energy in forward scattering angle 2°-5° and side scattering angle 80°-110° are discussed. Combining the analysis of cell's illuminating light energy, the peak, area, and full width at half maximum (FWHM) of label free cells' scattering pulses for fine structure cells with diameter 1-20 μm are studied to extract the interrelations of scattering pulse's features and cell's morphology. The theoretical and experimental results show that cell's diameter and FWHM of its scattering pulse agree with approximate linear distribution; the peak and area of scattering pulse do not always increase with cell's diameter becoming larger, but when cell's diameter is less than about 16 μm the monotone increasing relation of scattering pulse peak or area with cell's diameter can be obtained. This relationship between the features of scattering pulse and cell's size is potentially a useful but very simple criterion to distinguishing malignant and normal cells by their sizes and morphologies in label free cells clinical examinations.

  6. Flexible PCPDTBT:PCBM solar cells with integrated grating structures

    DEFF Research Database (Denmark)

    Oliveira Hansen, Roana Melina de; Liu, Yinghui; Madsen, Morten

    2013-01-01

    spectra of the active layer. This optimized solar cell structure leads to an enhanced absorption in the active layer and thus improved short-circuit currents and power conversion efficiencies in the fabricated devices. Fabrication of the solar cells on thin polyimide substrates which are compatible......We report on development of flexible PCPDTBT:PCBM solar cells with integrated diffraction gratings on the bottom electrodes. The presented results address PCPDTBT:PCBM solar cells in an inverted geometry, which contains implemented grating structures whose pitch is tuned to match the absorption...... with the lithographically processed grating structures are done in order to obtain the efficiency enhancement in thin, flexible devices. © (2013) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only....

  7. Optical Coating Performance and Thermal Structure Design for Heat Reflectors of JWST Electronic Control Unit

    Science.gov (United States)

    Quijada, Manuel A.; Threat, Felix; Garrison, Matt; Perrygo, Chuck; Bousquet, Robert; Rashford, Robert

    2008-01-01

    The James Webb Space Telescope (JWST) consists of an infrared-optimized Optical Telescope Element (OTE) that is cooled down to 40 degrees Kelvin. A second adjacent component to the OTE is the Integrated Science Instrument Module, or ISIM. This module includes the electronic compartment, which provides the mounting surfaces and ambient thermally controlled environment for the instrument control electronics. Dissipating the 200 watts generated from the ISIM structure away from the OTE is of paramount importance so that the spacecraft's own heat does not interfere with the infrared light detected from distant cosmic sources. This technical challenge is overcome by a thermal subsystem unit that provides passive cooling to the ISIM control electronics. The proposed design of this thermal radiator consists of a lightweight structure made out of composite materials and low-emittance metal coatings. In this paper, we will present characterizations of the coating emittance, bidirectional reflectance, and mechanical structure design that will affect the performance of this passive cooling system.

  8. Single crystalline silicon solar cells with rib structure

    Science.gov (United States)

    Yoshiba, Shuhei; Hirai, Masakazu; Abe, Yusuke; Konagai, Makoto; Ichikawa, Yukimi

    2017-02-01

    To improve the conversion efficiency of Si solar cells, we have developed a thin Si wafer-based solar cell that uses a rib structure. The open-circuit voltage of a solar cell is known to increase with deceasing wafer thickness if the cell is adequately passivated. However, it is not easy to handle very thin wafers because they are brittle and are subject to warpage. We fabricated a lattice-shaped rib structure on the rear side of a thin Si wafer to improve the wafer's strength. A silicon nitride film was deposited on the Si wafer surface and patterned to form a mask to fabricate the lattice-shaped rib, and the wafer was then etched using KOH to reduce the thickness of the active area, except for the rib region. Using this structure in a Si heterojunction cell, we demonstrated that a high open-circuit voltage (VOC) could be obtained by thinning the wafer without sacrificing its strength. A wafer with thickness of 30 μm was prepared easily using this structure. We then fabricated Si heterojunction solar cells using these rib wafers, and measured their implied VOC as a function of wafer thickness. The measured values were compared with device simulation results, and we found that the measured VOC agrees well with the simulated results. To optimize the rib and cell design, we also performed device simulations using various wafer thicknesses and rib dimensions.

  9. Tensegrity I. Cell structure and hierarchical systems biology

    Science.gov (United States)

    Ingber, Donald E.

    2003-01-01

    In 1993, a Commentary in this journal described how a simple mechanical model of cell structure based on tensegrity architecture can help to explain how cell shape, movement and cytoskeletal mechanics are controlled, as well as how cells sense and respond to mechanical forces (J. Cell Sci. 104, 613-627). The cellular tensegrity model can now be revisited and placed in context of new advances in our understanding of cell structure, biological networks and mechanoregulation that have been made over the past decade. Recent work provides strong evidence to support the use of tensegrity by cells, and mathematical formulations of the model predict many aspects of cell behavior. In addition, development of the tensegrity theory and its translation into mathematical terms are beginning to allow us to define the relationship between mechanics and biochemistry at the molecular level and to attack the larger problem of biological complexity. Part I of this two-part article covers the evidence for cellular tensegrity at the molecular level and describes how this building system may provide a structural basis for the hierarchical organization of living systems--from molecule to organism. Part II, which focuses on how these structural networks influence information processing networks, appears in the next issue.

  10. Tensegrity I. Cell structure and hierarchical systems biology

    Science.gov (United States)

    Ingber, Donald E.

    2003-01-01

    In 1993, a Commentary in this journal described how a simple mechanical model of cell structure based on tensegrity architecture can help to explain how cell shape, movement and cytoskeletal mechanics are controlled, as well as how cells sense and respond to mechanical forces (J. Cell Sci. 104, 613-627). The cellular tensegrity model can now be revisited and placed in context of new advances in our understanding of cell structure, biological networks and mechanoregulation that have been made over the past decade. Recent work provides strong evidence to support the use of tensegrity by cells, and mathematical formulations of the model predict many aspects of cell behavior. In addition, development of the tensegrity theory and its translation into mathematical terms are beginning to allow us to define the relationship between mechanics and biochemistry at the molecular level and to attack the larger problem of biological complexity. Part I of this two-part article covers the evidence for cellular tensegrity at the molecular level and describes how this building system may provide a structural basis for the hierarchical organization of living systems--from molecule to organism. Part II, which focuses on how these structural networks influence information processing networks, appears in the next issue.

  11. Single crystalline silicon solar cells with rib structure

    Directory of Open Access Journals (Sweden)

    Shuhei Yoshiba

    2017-02-01

    Full Text Available To improve the conversion efficiency of Si solar cells, we have developed a thin Si wafer-based solar cell that uses a rib structure. The open-circuit voltage of a solar cell is known to increase with deceasing wafer thickness if the cell is adequately passivated. However, it is not easy to handle very thin wafers because they are brittle and are subject to warpage. We fabricated a lattice-shaped rib structure on the rear side of a thin Si wafer to improve the wafer’s strength. A silicon nitride film was deposited on the Si wafer surface and patterned to form a mask to fabricate the lattice-shaped rib, and the wafer was then etched using KOH to reduce the thickness of the active area, except for the rib region. Using this structure in a Si heterojunction cell, we demonstrated that a high open-circuit voltage (VOC could be obtained by thinning the wafer without sacrificing its strength. A wafer with thickness of 30 μm was prepared easily using this structure. We then fabricated Si heterojunction solar cells using these rib wafers, and measured their implied VOC as a function of wafer thickness. The measured values were compared with device simulation results, and we found that the measured VOC agrees well with the simulated results. To optimize the rib and cell design, we also performed device simulations using various wafer thicknesses and rib dimensions.

  12. Manifold seal structure for fuel cell stack

    Science.gov (United States)

    Collins, William P.

    1988-01-01

    The seal between the sides of a fuel cell stack and the gas manifolds is improved by adding a mechanical interlock between the adhesive sealing strip and the abutting surface of the manifolds. The adhesive is a material which can flow to some extent when under compression, and the mechanical interlock is formed providing small openings in the portion of the manifold which abuts the adhesive strip. When the manifolds are pressed against the adhesive strips, the latter will flow into and through the manifold openings to form buttons or ribs which mechanically interlock with the manifolds. These buttons or ribs increase the bond between the manifolds and adhesive, which previously relied solely on the adhesive nature of the adhesive.

  13. Guidance of mesenchymal stem cells on fibronectin structured hydrogel films.

    Directory of Open Access Journals (Sweden)

    Annika Kasten

    Full Text Available Designing of implant surfaces using a suitable ligand for cell adhesion to stimulate specific biological responses of stem cells will boost the application of regenerative implants. For example, materials that facilitate rapid and guided migration of stem cells would promote tissue regeneration. When seeded on fibronectin (FN that was homogeneously immmobilized to NCO-sP(EO-stat-PO, which otherwise prevents protein binding and cell adhesion, human mesenchymal stem cells (MSC revealed a faster migration, increased spreading and a more rapid organization of different cellular components for cell adhesion on fibronectin than on a glass surface. To further explore, how a structural organization of FN controls the behavior of MSC, adhesive lines of FN with varying width between 10 µm and 80 µm and spacings between 5 µm and 20 µm that did not allow cell adhesion were generated. In dependance on both line width and gaps, cells formed adjacent cell contacts, were individually organized in lines, or bridged the lines. With decreasing sizes of FN lines, speed and directionality of cell migration increased, which correlated with organization of the actin cytoskeleton, size and shape of the nuclei as well as of focal adhesions. Together, defined FN lines and gaps enabled a fine tuning of the structural organization of cellular components and migration. Microstructured adhesive substrates can mimic the extracellular matrix in vivo and stimulate cellular mechanisms which play a role in tissue regeneration.

  14. Geographic variation, genetic structure and conservation unit designation in the larch mountain salamander( Plethodon larselli)

    Science.gov (United States)

    Wagner, R.S.; Miller, Mark P.; Crisafulli, Charles; Haig, Susan M.

    2005-01-01

    The Larch Mountain salamander (Plethodon larselli Burns, 1954) is an endemic species in the Pacific northwestern United States facing threats related to habitat destruction. To facilitate development of conservation strategies, we used DNA sequences and RAPDs (random amplified polymorphic DNA) to examine differences among populations of this species. Phylogenetic analyses of cytochrome b revealed a clade of haplotypes from populations north of the Columbia River derived from a clade containing haplotypes from the river's southwestern region. Haplotypes from southeastern populations formed a separate clade. Nucleotide diversity was reduced in northern populations relative to southern populations. These results were corroborated by analyses of RAPD loci, which revealed similar patterns of clustering and diversity. Network analyses suggested that northern populations were colonized following a range expansion mediated by individuals from populations located southwest of the river. Changes in the Columbia River's location during the Pliocene and Pleistocene likely released distributional constraints on this species, permitting their northern range expansion. Based on the barrier presented by the Columbia River's present location and differences in haplotype diversity and population structure observed between northern and southern populations, we suggest that designation of separate management units encompassing each region may assist with mitigating different threats to this species.

  15. Stratigraphic structure of the B1 Tertiary tectonostratigraphic unit in eastern Slovenia

    Directory of Open Access Journals (Sweden)

    Bogomir Jelen

    2002-06-01

    Full Text Available High inconsistency and incoherence in the stratigraphy of the Slovenian upper Paleogene and lower Miocene have remained unsolved in the past 150 years. To solve the problem, we tried to rigorously conduct the authentic Galilei’s scientific method. Steps of logical and empirical verification confirmed the existence of the posited B1 Tertiary tectonostratigraphic unit, and a general chronostratigraphic model of new positional relationships of lithologic units resulted from rather good biochronostratigraphic resolution achieved by nannoplankton and planktonic foraminifera biostratigraphy. The application of principles of newly developed fields in science helped us to avoid errors in transmission of messages (to reduce noise from the source (rock to the concept formation,which had been done previously. This in turn has strongly reduced inconsistency andincoherence (high information entropy = uncertainty. The released amount of information enabled us to answer also questions that reached beyond the original difficulty, e.g.: is the tectonostratigraphic structure of eastern Slovenia a manifestation of plate tectonics processes, and of which ones, are theories of continental escape in the Alps and associated dissection and offset of the formerly uniform Slovenian-Hungarian Paleogene basin tenableor not, are then there in the B1 stratigraphic equivalents of the Hungarian Paleogene basin formations, where are the important Eocene / Oligocene, Paleogene / Neogene, Rupelian / Chattian and Kiscellian / Egerian boundaries in Slovenia, and is there acontinuation of the B1 in Croatia and in the Mid-Hungarian tectonic zone?

  16. Internal structure of Family Health Units: access for people with disabilities.

    Science.gov (United States)

    Martins, Kaisy Pereira; Costa, Tatiana Ferreira da; Medeiros, Thayris Mariano de; Fernandes, Maria das Graças Melo; França, Inácia Sátiro Xavier de; Costa, Kátia Nêyla de Freitas Macêdo

    2016-10-01

    This study aimed at evaluating the internal structure of Family Health Units in relation to the access of people with physical and/or sensory disabilities. It is a descriptive, exploratory, population-based research, held in Family Health Units of the municipality of João Pessoa, Paraíba, Brazil. For the collection of data, a checklist based on Technical Standard 9050 was used. For the analysis, the descriptive and exploratory analysis of the data and the Chi-square test were applied. As a result, of the 90 buildings evaluated, only 47.8% have a wheelchair ramp, of these 30.0% have maximum slope and 32.2% have anti-slip flooring. In 28.9% access happens through a staircase without handrail and in 6.7% through a staircase with handrail, 6.7% of these with anti-slip flooring. And only 17.8% of sliding doors have lowered tracks. We concluded that it must be recognized that public policies and institutions do not correspond to the need of these people, and it is necessary to reformulate this form of care and reorganize health services.

  17. The Structure of Plant Cell Walls: II. The Hemicellulose of the Walls of Suspension-cultured Sycamore Cells.

    Science.gov (United States)

    Bauer, W D; Talmadge, K W; Keegstra, K; Albersheim, P

    1973-01-01

    The molecular structure, chemical properties, and biological function of the xyloglucan polysaccharide isolated from cell walls of suspension-cultured sycamore (Acer pseudoplatanus) cells are described. The sycamore wall xyloglucan is compared to the extracellular xyloglucan secreted by suspension-cultured sycamore cells into their culture medium and is also compared to the seed "amyloid" xyloglucans.Xyloglucan-or fragments of xyloglucan-and acidic fragments of the pectic polysaccharides are released from endopolygalacturonase-pretreated sycamore walls by treatment of these walls with 8 m urea, endoglucanase, or 0.5 n NaOH. Some of the xyloglucan thus released is found to cochromatograph with the acidic pectic fragments on diethylaminoethyl Sephadex. The chemical or enzymic treatments required for the release of xyloglucan from the walls and the cochromatography of xyloglucan with the acidic pectic fragments indicate that xyloglucan is covalently linked to the pectic polysaccharides and is noncovalently bound to the cellulose fibrils of the sycamore cell wall.The molecular structure of sycamore xyloglucan was characterized by methylation analysis of the oligosaccharides obtained by endoglucanase treatment of the polymer. The structure of the polymer is based on a repeating heptasaccharide unit which consists of 4 residues of beta-1-4-linked glucose and 3 residues of terminal xylose. A single xylose residue is glycosidically linked to carbon 6 of 3 of the glucosyl residues.

  18. Structure and Function: Planning a New Intensive Care Unit to Optimize Patient Care

    Directory of Open Access Journals (Sweden)

    Jozef Kesecioğlu

    2014-08-01

    Full Text Available To survey the recent medical literature reporting effects of intensive care unit (ICU design on patients’ and family members’ well-being, safety and functionality. Features of ICU design linked to the needs of patients and their family are single-rooms, privacy, quiet surrounding, exposure to daylight, views of nature, prevention of infection, a family area and open visiting hours. Other features such as safety, working procedures, ergonomics and logistics have a direct impact on the patient care and the nursing and medical personnel. An organization structured on the needs of the patient and their family is mandatory in designing a new intensive care. The main aims in the design of a new department should be patient centered care, safety, functionality, innovation and a future-proof concept.

  19. China's laws, rights, and administrative structures in occupational safety and health: a comparison with the United States.

    Science.gov (United States)

    Sun, Yinling; Xu, Lingzhong; Shao, Hua; Wang, He

    2014-11-01

    China has achieved rapid economic development, but faces tremendous challenges in occupational safety and health (OSH). We describe China's laws, rights, and administrative structures in OSH and in workers' compensation. The article compares these with comparable laws, rights, and administrative structures in the United States. We hope this comparison may provide useful lessons for continued OSH development and improvement in China.

  20. Structure and Control Strategies of Fuel Cell Vehicle

    Institute of Scientific and Technical Information of China (English)

    宋建国; 张承宁; 孙逢春; 钟秋海

    2004-01-01

    The structure and kinds of the fuel cell vehicle (FCV) and the mathematical model of the fuel cell processor are discussed in detail. FCV includes many parts: the fuel cell thermal and water management, fuel supply, air supply and distribution, AC motor drive, main and auxiliary power management, and overall vehicle control system. So it requires different kinds of control strategies, such as the PID method, zero-pole method, optimal control method, fuzzy control and neural network control. Along with the progress of control method, the fuel cell vehicle's stability and reliability is up-and-up. Experiment results show FCV has high energy efficiency.

  1. Structural and functional classes of multipolar cells in the ventral cochlear nucleus.

    Science.gov (United States)

    Doucet, John R; Ryugo, David K

    2006-04-01

    Multipolar cells in the ventral cochlear nucleus (VCN) are a structurally and functionally diverse group of projection neurons. Understanding their role in the ascending pathway involves partitioning multipolar cells into distinct populations and determining where in the brain each sends its coded messages. In this study, we used retrograde labeling techniques in rats to identify multipolar neurons that project their axons to the ipsilateral dorsal cochlear nucleus (DCN), the contralateral CN, or both structures. Three rats received injections of biotinylated dextran amine in the ipsilateral DCN and diamidino yellow in the contralateral CN. Several radiate multipolar neurons (defined by their axonal projections to the ipsilateral DCN and their dendrites that traverse VCN isofrequency sheets) were double-labeled but over 70% were not. This result suggests two distinct populations: (1) radiate-commissural (RC) multipolar cells that project to the ipsilateral DCN and the contralateral CN, and (2) radiate multipolar cells that project exclusively (in this context) to the ipsilateral DCN. In a different group of animals, we retrogradely labeled multipolar neurons that project their axons to the contralateral CN and measured the size of their cell bodies. The mean size of this population (266 +/- 156 microm2) was significantly smaller than those of RC-multipolar cells (418 +/- 140 microm2). We conclude that the CN commissural pathway is composed of at least two components: (1) RC multipolar cells and (2) commissural multipolar cells that are small- and medium-sized neurons that project exclusively (in this context) to the contralateral CN. These results identify separate structural groups of multipolar cells that may correspond to physiological unit types described in the literature. They also provide protocols for isolating and studying different populations of multipolar cells to determine the neural mechanisms that govern their responses to sound.

  2. Evaluation of structural deformations of a mechanical connecting unit oxidizer supplies by thermo-mechanical simulation

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Sang Woo [Dept. of Mechanical Engineering, Institute of Machine Convergence Technology, Hankyong National University, Anseong (Korea, Republic of)

    2016-10-15

    A Mechanical connecting unit (MCU) used in ground facilities for a Liquid propellant rocket (LPR) acts as a bridge between the onboard system and the ground oxidizer filling system. It should be resistant to structural deformations in order to guarantee successful supply of a cryogenic oxidizer and high pressure gases without reduction of sealing capability. The MCU consists of many components and linkages and operates under harsh conditions induced by a cryogenic oxidizer, high pressure gases and other mechanical forces. Thus, the evaluation of structural deformation of the MCU considering complex conditions is expensive and time consuming. The present study efficiently evaluates the structural deformations of the key components of the MCU by Thermo-mechanical simulation (TMS) based on the superposition principle. Deformations due to the mechanical loadings including weights, pressures, and spring forces are firstly evaluated by using a non-linear flexible body simulation module (FFlex) of Multi-body dynamics (MBD) software, RecurDyn. Then, thermal deformations for the deformed geometries obtained by RecurDyn were subsequently calculated. It was conducted by using a Finite element (FE) analysis software, ANSYS. The total deformations for the onboard plate and multi-channel plate in the connecting section due to the mechanical and thermal loadings were successfully evaluated. Moreover, the outer gaps at six points between two plates were calculated and verified by comparison to the measured data. Their values and tendencies showed a good agreement. The author concluded that the TMS using MBD software considering flexible bodies and an FE simulator can efficiently evaluate structural deformations of the MCU operating under the complex load and boundary conditions.

  3. Selective Laser Melting: a regular unit cell approach for the manufacture of porous, titanium, bone in-growth constructs, suitable for orthopedic applications.

    Science.gov (United States)

    Mullen, Lewis; Stamp, Robin C; Brooks, Wesley K; Jones, Eric; Sutcliffe, Christopher J

    2009-05-01

    In this study, a novel porous titanium structure for the purpose of bone in-growth has been designed, manufactured and evaluated. The structure was produced by Selective Laser Melting (SLM); a rapid manufacturing process capable of producing highly intricate, functionally graded parts. The technique described utilizes an approach based on a defined regular unit cell to design and produce structures with a large range of both physical and mechanical properties. These properties can be tailored to suit specific requirements; in particular, functionally graded structures with bone in-growth surfaces exhibiting properties comparable to those of human bone have been manufactured. The structures were manufactured and characterized by unit cell size, strand diameter, porosity, and compression strength. They exhibited a porosity (10-95%) dependant compression strength (0.5-350 Mpa) comparable to the typical naturally occurring range. It is also demonstrated that optimized structures have been produced that possesses ideal qualities for bone in-growth applications and that these structures can be applied in the production of orthopedic devices.

  4. A dimeric structure of PD-L1: functional units or evolutionary relics?

    OpenAIRE

    Chen, Yong; Liu, Peipei; Gao, Feng; Cheng, Hao; Qi, Jianxun; Gao, George F

    2010-01-01

    PD-L1 is a member of the B7 protein family, most of whose members so far were identified as dimers in a solution and crystalline state, either complexed or uncomplexed with their ligand(s). The binding of PD-L1 with its receptor PD-1 (CD279) delivers an inhibitory signal regulating the T cell function. Simultaneously with the Garboczi group, we successfully solved another structure of human PD-L1 (hPD-L1). Our protein crystallized in the space group of C2221 with two hPD-L1 molecules per asym...

  5. Major design issues of molten carbonate fuel cell power generation unit

    Energy Technology Data Exchange (ETDEWEB)

    Chen, T.P.

    1996-04-01

    In addition to the stack, a fuel cell power generation unit requires fuel desulfurization and reforming, fuel and oxidant preheating, process heat removal, waste heat recovery, steam generation, oxidant supply, power conditioning, water supply and treatment, purge gas supply, instrument air supply, and system control. These support facilities add considerable cost and system complexity. Bechtel, as a system integrator of M-C Power`s molten carbonate fuel cell development team, has spent substantial effort to simplify and minimize these supporting facilities to meet cost and reliability goals for commercialization. Similiar to other fuels cells, MCFC faces design challenge of how to comply with codes and standards, achieve high efficiency and part load performance, and meanwhile minimize utility requirements, weight, plot area, and cost. However, MCFC has several unique design issues due to its high operating temperature, use of molten electrolyte, and the requirement of CO2 recycle.

  6. Radial microwire array solar cell with pyramidal structure

    Science.gov (United States)

    Priyadarshini, Bindu; Das, Mukul Kumar; Sen, Mrinal; Kumar, Subindu

    2016-10-01

    In this work, a theoretical model for radial p-n junction microwire array solar cell with pyramidal structures in the space between microwires has been developed. Incorporation of pyramidal structures results in reflection of light, which would otherwise be unused, and illuminates side walls of the microwires. This additional illumination enhances absorption and, hence, efficiency of the whole structure. Efficiency enhancement is analyzed by varying different device parameters e.g., radius and length of each microwire and packing fraction of the structure. Results show that the maximum fractional efficiency enhancement can be obtained as 30% by suitable choice of these parameters.

  7. Cell phone recycling experiences in the United States and potential recycling options in Brazil.

    Science.gov (United States)

    Silveira, Geraldo T R; Chang, Shoou-Yuh

    2010-11-01

    This paper presents an overview of cell phone recycling programs currently available in the United States. At the same time, it also provides analyses of the current recycling situation and possible recycling alternatives for Brazil. Although there are several recycling options in the United States, collection rates are still only 10% of all potential devices because customers are not aware of these possibilities. The whole system is financially based on reselling refurbished cell phones and recycled materials to developing countries which represent an effective and strong market. Several recyclers offer funds to collection partners who are either charities or who work with charities while obtaining the materials that they need in order to run their operations. A mobile phone recycling system for Brazil considering the United States experience and the Extended Producer Responsibility (EPR) principle is suggested. A deposit/refund/advance-recycling fee is proposed which might be implemented as a voluntary industrial initiative managed by PRO Brazil, a producer responsibility organization. One widespread public-private agreement will integrate all mobile phone stakeholders, and environmental education actions and promotional events will promote citizen's participation.

  8. Study of organic solar cells with stacked bulk heterojunction structure

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xin-fang; XU Zheng; ZHAO Su-ling; ZHANG Fu-jun; LI Yan; WU Chun-yu; CHEN Yue-ning

    2008-01-01

    Organic solar cells with stacked bulk heterojunction(BHJ) are investigated based on conjugated polymer. By using the solution spin-coating method, Poly[2-methoxy, 5-(2'-ethyl-hexyloxy) -1,4-phenylene vinylene] (MEH-PPV) and ZnO nanoparticles (50 nm) are mixed as the optical sense layer. Ag is used as inter-layer to connect the upper BILl cell and the lower cell. The structures are ITO/PEDOT:PSS/MEH-PPV/Ag/MEH-PPV:ZnO/Al. The open circuit voltage (Voc) of a stacked cell is about 3.7 times of that of an individual organic solar cell (ITO/PEDOT:PSS/MEH-PPV/A1). The short circuit current (Jsc) of a stacked cell is increased by about 1.6 times of that of individual one.

  9. Synthesis and properties of two novel copolymers based on squaraine and fluorene units for solar cell materials

    Institute of Scientific and Technical Information of China (English)

    Zheng Wang; Wei Zhang; Feng Tao; Kai Ge Meng; Long Yi Xi; Ying Li; Qing Jiang

    2011-01-01

    Two novel copolymers based on squaraine and fluorine units have been synthesized through palladium catalyzed Suzuki coupling reaction and Sonogashira coupling reaction, respectively. The structures and properties of the two copolymers were characterized by FT-IR, NMR, UV-vis absorbance (Abs), gel permeation chromatography (GPC), thermal gravimetric analysis (TGA), differential scanning calorimetry (DSC) and cyclic voltammetry (CV). The solution absorption spectrums of P1 and P2 show two distinct absorption bands, one locates at 300-500 nm and the other at 600-800 nm. The absorption spectrums of P1 and P2 in films are broadened obviously and the spectral responses are extended up to 900 nm. Thermal gravimetric analysis demonstrates that the polymers are stable. Cyclic voltammetry experiment shows that the band gaps of the copolymers are 1.65 eV and 1.67 eV, respectively, suggesting their potential for applications as solar cells materials.

  10. Laser Molecular Beam Epitaxy Growth of BaTiO3 in Seven Thousands of Unit-Cell Layers

    Institute of Scientific and Technical Information of China (English)

    HUANG Yan-Hong; YANG Guo-Zhen; HE Meng; ZHAO Kun; TIAN Huan-Fang; L(U) Hui-Bin; JIN Kui-Juan; CHEN Zheng-Hao; ZHOU Yue-Liang; LI Jian-Qi

    2005-01-01

    @@ BaTiO3 thin films in seven thousands of unit-cell layers have been successfully fabricated on SrTiO3 (001)substrates by laser molecular beam epitaxy. The fine streak pattern and the undamping intensity oscillation of reflection high-energy electron diffraction indicate that the BaTiO3 film was layer-by-layer epitaxial growth. The measurements of scanning electron microscopy and atomic force microscopy show that surfaces of the BaTiO3thin film are atomically smooth. The measurements of x-ray diffraction and transmission electron microscopy,as well as selected-area electron diffraction revealthat the BaTiO3 thin film is a c-oriented epitaxial crystalline structure.

  11. Revisiting the Unit Root Hypothesis and Structural Break: Asia and Emerging Economies Foreign Exchange Markets

    Directory of Open Access Journals (Sweden)

    Christopher Gan

    2004-01-01

    Full Text Available This study examines the stationary of ten Asian and for emerging Foreign Exchange (FX rates during the 1990s. The paper employs the Augmented Dickey-Fuller (ADF unit root test to the following FX rates: Hong Kong Dollar (HKD Japanese Yen (JPY, South Korean won (KRW new Taiwan dollar (TWN, Chinese Renminbl (CHR, Indonesia Rupiah (IDR, Malaysian Ringgit (MYR, Singapore Dollar (SGD, Thai Bhat (THB, Philippines Peso (PHP, Argentine Peso (AGP, the Brazilian Real (BRR, Mexican Peso (MXP and Russian Rouble (RUR. Structural break is taken into account for series found to be non-stationary using the[1] test. The results show that exchange rate series were found to be non-stationary except for the Chinese Renminbi, Mexican and Argentina pesos. Furthermore, the robustness test indicates that the ADF test is robust across different data frequencies for most series we examined finally; we find the choice of structural break data is crucial in testing that stationary for most series examined.

  12. Four-dimensional structural and Doppler optical coherence tomography imaging on graphics processing units.

    Science.gov (United States)

    Sylwestrzak, Marcin; Szlag, Daniel; Szkulmowski, Maciej; Gorczynska, Iwona; Bukowska, Danuta; Wojtkowski, Maciej; Targowski, Piotr

    2012-10-01

    The authors present the application of graphics processing unit (GPU) programming for real-time three-dimensional (3-D) Fourier domain optical coherence tomography (FdOCT) imaging with implementation of flow visualization algorithms. One of the limitations of FdOCT is data processing time, which is generally longer than data acquisition time. Utilizing additional algorithms, such as Doppler analysis, further increases computation time. The general purpose computing on GPU (GPGPU) has been used successfully for structural OCT imaging, but real-time 3-D imaging of flows has so far not been presented. We have developed software for structural and Doppler OCT processing capable of visualization of two-dimensional (2-D) data (2000 A-scans, 2048 pixels per spectrum) with an image refresh rate higher than 120 Hz. The 3-D imaging of 100×100 A-scans data is performed at a rate of about 9 volumes per second. We describe the software architecture, organization of threads, and optimization. Screen shots recorded during real-time imaging of a flow phantom and the human eye are presented.

  13. Apparent glacially induced structural controls on limestone conduit development in Ohio Caverns, United States

    Directory of Open Access Journals (Sweden)

    Adrienne M. Watts

    2016-01-01

    Full Text Available Rock discontinuities such as bedding planes and joints are important controls on the form that caves take. We examined structural controls on the development of Ohio Caverns. The cave formed in Devonian limestone underlying a small bedrock knob (Mt. Tabor within the Interior Lowland province, United States. The area has been overridden by continental glaciation multiple times. The bedrock is pervasively fractured, with many curved and wavy near-vertical fractures showing many different orientations. In the case of Ohio Caverns, it appears that the controlling fractures in map view may not be joints sensu stricto, but rather some combination of tensile and shear (mode-1 and mode-2 fractures, probably forming in the regime transition between tensile and shear fracturing. This is easy to envision in a situation with ice advancing over this topographic high, and would result in the curved fractures that are observed in many places in the cave. It can also explain the numerous fracture directions. However, not all fractures are conduit-significant. The cave initiated on or near a single bedding plane, and the cave passages exhibit strong keyhole or plus-sign cross sections. Passage and fracture orientations are inconsistent with regionally expected directions. It is likely that mechanical, hydraulic, and thermal stresses related to glaciation caused the fracturing in Mt. Tabor. The cave then developed on this template according to local hydrologic conditions. This presents a newly documented structural template sub-type for cave development.

  14. Structure–Activity Relationship of Oligomeric Flavan-3-ols: Importance of the Upper-Unit B-ring Hydroxyl Groups in the Dimeric Structure for Strong Activities

    Directory of Open Access Journals (Sweden)

    Yoshitomo Hamada

    2015-10-01

    Full Text Available Proanthocyanidins, which are composed of oligomeric flavan-3-ol units, are contained in various foodstuffs (e.g., fruits, vegetables, and drinks and are strongly biologically active compounds. We investigated which element of the proanthocyanidin structure is primarily responsible for this functionality. In this study, we elucidate the importance of the upper-unit of 4–8 condensed dimeric flavan-3-ols for antimicrobial activity against Saccharomyces cerevisiae (S. cerevisiae and cervical epithelioid carcinoma cell line HeLa S3 proliferation inhibitory activity. To clarify the important constituent unit of proanthocyanidin, we synthesized four dimeric compounds, (−-epigallocatechin-[4,8]-(+-catechin, (−-epigallocatechin-[4,8]-(−-epigallocatechin, (−-epigallocatechin-[4,8]-(−-epigallocatechin-3-O-gallate, and (+-catechin-[4,8]-(−-epigallocatechin and performed structure–activity relationship (SAR studies. In addition to antimicrobial activity against S. cerevisiae and proliferation inhibitory activity on HeLa S3 cells, the correlation of 2,2-diphenyl-l-picrylhydrazyl radical scavenging activity with the number of phenolic hydroxyl groups was low. On the basis of the results of our SAR studies, we concluded that B-ring hydroxyl groups of the upper-unit of the dimer are crucially important for strong and effective activity.

  15. Control structures design for fossil power station units; Diseno de estructuras de control para unidades termoelectricas

    Energy Technology Data Exchange (ETDEWEB)

    Palomares Gonzalez, Daniel; Ricano Castillo, Juan Manuel [Instituto de Investigaciones Electricas, Cuernavaca (Mexico)

    1989-12-31

    In this paper are designed an analyzed the control ties of a 300MW fossil unit at different operation levels. The design and analysis were developed on an operation range of 50% to 100% load. The main control ties were studied among which are the feedwater flow, the superheating zone temperatures and the generated output. The technique used for the design is the decomposition in singular values (DSV) of the plant transference matrix. This is a recent technique that permits finding the most important interactions among output-input variables, over a significative frequencies range for the transference matrix of the plant. For this purpose utilizes the control properties of the transference matrix, such as: control effort, output-input interaction and ruggedness with respect to uncertainties. The control structures obtained were tested in a digital model of a fossil plant unit. A comparison study of both structures (original and modified) showed enhancement in the performance of the power plant with modified structure. [Espanol] En este trabajo se disenan y analizan los lazos de control de una unidad termoelectrica de 300 MW, a diferentes niveles de operacion. El diseno y analisis se desarrollo sobre un rango de operacion de 50 a 100 por ciento de carga. Se estudiaron los principales lazos de control entre los que se encuentran el flujo de agua de alimentacion, las temperaturas de la zona de sobrecalentamiento y la potencia generada. La tecnica utilizada para el diseno es la descomposicion en valores singulares (DVS) de la matriz de transferencia de la planta. Esta es una tecnica reciente que permite encontrar las interacciones mas importantes entre variables entrada-salida, sobre un rango de frecuencias significativas para la matriz de transferencia de la planta. Utiliza para ello las propiedades de control de la matriz de transferencia, como son: esfuerzo de control, interaccion entrada-salida y robustez con respecto a incertidumbres. Las estructuras de control

  16. Comparative structural biology of the genome: nano-scale imaging of single nucleus from different kingdoms reveals the common physicochemical property of chromatin with a 40 nm structural unit.

    Science.gov (United States)

    Kobori, Toshiro; Kodama, Mami; Hizume, Kohji; Yoshimura, Shige H; Ohtani, Toshio; Takeyasu, Kunio

    2006-01-01

    Genome function is closely linked to the higher-order chromatin structures. To reveal a structural basis for the interphase chromatin organization, the 'on-substrate' lysis procedure was applied to nuclei isolated from human HeLa cells, chicken erythrocyte cells and yeast Schizosaccharomyces pombe, which possessed different intrinsic properties of the genomes such as histone composition and inter-nucleosomal distance. The isolated nuclei on a coverslip were successively treated with a detergent and a high-salt solution to extract the nuclear membrane and the nucleoplasm, and therefore, atomic force microscopy (AFM) visualized the structural changes in response to the lysis procedure. After the nucleoplasm was extracted, AFM clarified that chromatin fibers, approximately 40 nm in width, were partially released out of the nuclei and that the other chromatin still remaining in the nuclei was composed of granular structures with diameter of 80-100 nm. Thus, these results suggest that the approximately 40 nm fiber would be a stable structural unit and fold the 80-100 nm granules into a one-step higher unit. A common mechanism could be implied regardless of the intrinsic properties of the eukaryotic genomes.

  17. Helium 23P Fine Structure Measurement in a Discharge Cell

    Science.gov (United States)

    Zelevinsky, T.; Farkas, D.; Gabrielse, G.

    2005-12-01

    A precise measurement of helium 23P fine structure was carried out in a discharge cell using Doppler-free laser spectroscopy. It is the only known experiment to directly measure all three fine structure intervals at a 1 kHz level of accuracy. The 23P1 - 23P2 interval value agrees with other experiments but disagrees with theoretical predictions of two-electron QED. When this disagreement is resolved, the 23P0 - 23P1 interval measurement reported here will allow a determination of the fine structure constant to 14 parts in 109, surpassing the precision of the well known QED-independent quantum Hall effect and Josephson effect determinations. The discharge cell is shown to be advantageous in the study and correction of systematic frequency shifts related to light pressure, and the use of the cell ensures that the possible systematic errors are substantially different from those reported in other experiments.

  18. Single-unit-cell layer established Bi 2 WO 6 3D hierarchical architectures: Efficient adsorption, photocatalysis and dye-sensitized photoelectrochemical performance

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Hongwei; Cao, Ranran; Yu, Shixin; Xu, Kang; Hao, Weichang; Wang, Yonggang; Dong, Fan; Zhang, Tierui; Zhang, Yihe

    2017-12-01

    Single-layer catalysis sparks huge interests and gains widespread attention owing to its high activity. Simultaneously, three-dimensional (3D) hierarchical structure can afford large surface area and abundant reactive sites, contributing to high efficiency. Herein, we report an absorbing single-unit-cell layer established Bi2WO6 3D hierarchical architecture fabricated by a sodium dodecyl benzene sulfonate (SDBS)-assisted assembled strategy. The DBS- long chains can adsorb on the (Bi2O2)2+ layers and hence impede stacking of the layers, resulting in the single-unit-cell layer. We also uncovered that SDS with a shorter chain is less effective than SDBS. Due to the sufficient exposure of surface O atoms, single-unit-cell layer 3D Bi2WO6 shows strong selectivity for adsorption on multiform organic dyes with different charges. Remarkably, the single-unit-cell layer 3D Bi2WO6 casts profoundly enhanced photodegradation activity and especially a superior photocatalytic H2 evolution rate, which is 14-fold increase in contrast to the bulk Bi2WO6. Systematic photoelectrochemical characterizations disclose that the substantially elevated carrier density and charge separation efficiency take responsibility for the strengthened photocatalytic performance. Additionally, the possibility of single-unit-cell layer 3D Bi2WO6 as dye-sensitized solar cells (DSSC) has also been attempted and it was manifested to be a promising dye-sensitized photoanode for oxygen evolution reaction (ORR). Our work not only furnish an insight into designing single-layer assembled 3D hierarchical architecture, but also offer a multi-functional material for environmental and energy applications.

  19. The effect of a cholesterol liquid crystalline structure on osteoblast cell behavior.

    Science.gov (United States)

    Xu, Jian-Ping; Ji, Jian; Shen, Jia-Cong

    2009-04-01

    To investigate the effect of a liquid crystalline structure on cell behavior, polymethylsiloxane-graft-(10-cholesteryloxydecanol) was specially designed to get a thermotropic liquid crystalline polymer. Results of Fourier transform infrared (FT-IR) spectroscopy, proton nuclear magnetic resonance (1H-NMR) spectroscopy and gel permeation chromatography (GPC) indicated that cholesterol was successfully covalently grafted onto polymethylhydrosiloxane via decamethylene 'flexible spacer'. Differential scanning calorimetry (DSC) and polarized optical microscopy (POM) investigations revealed that the copolymer with 44.9% mesogenic unit showed obvious thermotropic liquid crystalline transition at about 124.9 degrees C. Polymer films were prepared by spin coating on clean glass plates from 5 mg ml(-1) toluene solutions of the copolymers. The POM investigation indicated that while the unannealed films (SC15, SC45) showed no liquid crystalline structure, the films which were annealed in vacuo at 140 degrees C for 9 h and then quenched to room temperature (SC15C, SC45C) formed discrete island-like liquid crystalline and continuous liquid crystalline structures, respectively. Osteoblast cells (MC3T3) were chosen to test the cell behavior of annealed and unannealed films. In comparison to unannealed films, the annealed films with a cholesterol liquid crystalline structure could promote osteoblast cell attachment and growth significantly.

  20. Planar conjugated polymers containing 9,10-disubstituted phenanthrene units for efficient polymer solar cells.

    Science.gov (United States)

    Li, Guangwu; Kang, Chong; Li, Cuihong; Lu, Zhen; Zhang, Jicheng; Gong, Xue; Zhao, Guangyao; Dong, Huanli; Hu, Wenping; Bo, Zhishan

    2014-06-01

    Four novel conjugated polymers (P1-4) with 9,10-disubstituted phenanthrene (PhA) as the donor unit and 5,6-bis(octyloxy)benzothiadiazole as the acceptor unit are synthesized and characterized. These polymers are of medium bandgaps (2.0 eV), low-lying HOMO energy levels (below -5.3 eV), and high hole mobilities (in the range of 3.6 × 10(-3) to 0.02 cm(2) V(-1) s(-1) ). Bulk heterojunction (BHJ) polymer solar cells (PSCs) with P1-4:PC71 BM blends as the active layer and an alcohol-soluble fullerene derivative (FN-C60) as the interfacial layer between the active layer and cathode give the best power conversion efficiency (PCE) of 4.24%, indicating that 9,10-disubstituted PhA are potential donor materials for high-efficiency BHJ PSCs.

  1. Prokaryotic cells: structural organisation of the cytoskeleton and organelles

    Directory of Open Access Journals (Sweden)

    Wanderley de Souza

    2012-05-01

    Full Text Available For many years, prokaryotic cells were distinguished from eukaryotic cells based on the simplicity of their cytoplasm, in which the presence of organelles and cytoskeletal structures had not been discovered. Based on current knowledge, this review describes the complex components of the prokaryotic cell cytoskeleton, including (i tubulin homologues composed of FtsZ, BtuA, BtuB and several associated proteins, which play a fundamental role in cell division, (ii actin-like homologues, such as MreB and Mb1, which are involved in controlling cell width and cell length, and (iii intermediate filament homologues, including crescentin and CfpA, which localise on the concave side of a bacterium and along its inner curvature and associate with its membrane. Some prokaryotes exhibit specialised membrane-bound organelles in the cytoplasm, such as magnetosomes and acidocalcisomes, as well as protein complexes, such as carboxysomes. This review also examines recent data on the presence of nanotubes, which are structures that are well characterised in mammalian cells that allow direct contact and communication between cells.

  2. Prokaryotic cells: structural organisation of the cytoskeleton and organelles.

    Science.gov (United States)

    Souza, Wanderley de

    2012-05-01

    For many years, prokaryotic cells were distinguished from eukaryotic cells based on the simplicity of their cytoplasm, in which the presence of organelles and cytoskeletal structures had not been discovered. Based on current knowledge, this review describes the complex components of the prokaryotic cell cytoskeleton, including (i) tubulin homologues composed of FtsZ, BtuA, BtuB and several associated proteins, which play a fundamental role in cell division, (ii) actin-like homologues, such as MreB and Mb1, which are involved in controlling cell width and cell length, and (iii) intermediate filament homologues, including crescentin and CfpA, which localise on the concave side of a bacterium and along its inner curvature and associate with its membrane. Some prokaryotes exhibit specialised membrane-bound organelles in the cytoplasm, such as magnetosomes and acidocalcisomes, as well as protein complexes, such as carboxysomes. This review also examines recent data on the presence of nanotubes, which are structures that are well characterised in mammalian cells that allow direct contact and communication between cells.

  3. Primary Cell Wall Structure in the Evolution of Land Plants

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Investigation of the primary cell walls of lower plants improves our understanding of the cell biology of these organisms but also has the potential to improve our understanding of cell wall structure and function in angiosperms that evolved from lower plants. Cell walls were prepared from eight species, ranging from a moss to advanced gymnosperms, and subjected to sequential chemical extraction to separate the main polysaccharide fractions. The glycosyl compositions of these fractions were then determined by gas chromatography. The results were compared among the eight plants and among data from related studies reported in the existing published reports to identify structural features that have been either highly conserved or clearly modified during evolution. Among the highly conserved features are the presence of a cellulose framework, the presence of certain hemicelluloses such as xyloglucan, and the presence of rhamnogalacturonan Ⅱ, a domain in pectic polysaccharides. Among the modified features are the abundance of mannosyl-containing hemicelluloses and the presence of methylated sugars.

  4. The role of polar, lamdba (Λ)-shaped building units in noncentrosymmetric inorganic structures.

    Science.gov (United States)

    Donakowski, Martin D; Gautier, Romain; Yeon, Jeongho; Moore, Donald T; Nino, Juan C; Halasyamani, P Shiv; Poeppelmeier, Kenneth R

    2012-05-01

    A methodology for the design of polar, inorganic structures is demonstrated here with the packing of lambda (Λ)-shaped basic building units (BBUs). Noncentrosymmetric (NCS) solids with interesting physical properties can be created with BBUs that lack an inversion center and are likely to pack into a polar configuration; previous methods to construct these solids have used NCS octahedra as BBUs. Using this methodology to synthesize NCS solids, one must increase the coordination of the NCS octahedra with maintenance of the noncentrosymmetry of the bulk. The first step in this progression from an NCS octahedron to an inorganic NCS solid is the formation of a bimetallic BBU. This step is exemplified with the compound CuVOF(4)(H(2)O)(7): this compound, presented here, crystallizes in an NCS structure with ordered, isolated [Cu(H(2)O)(5)](2+) cations and [VOF(4)(H(2)O)](2-) anions into Λ-shaped, bimetallic BBUs to form CuVOF(4)(H(2)O)(6)·H(2)O, owing to the Jahn-Teller distortion of Cu(2+). Conversely, the centrosymmetric heterotypes with the same formula MVOF(4)(H(2)O)(7) (M(II) = Co, Ni, and Zn) exhibit ordered, isolated [VOF(4)(H(2)O)](2-) and [M(H(2)O)(6)](2+) ionic species in a hydrogen bond network. CuVOF(4)(H(2)O)(7) exhibits a net polar moment while the heterotypes do not; this demonstrates that Λ-shaped BBUs give a greater probability for and, in this case, lead to NCS structures.

  5. Structural Studies of Complex Carbohydrates of Plant Cell Walls

    Energy Technology Data Exchange (ETDEWEB)

    Darvill, Alan [Univ. of Georgia, Athens, GA (United States); Hahn, Michael G. [Univ. of Georgia, Athens, GA (United States); O' Neill, Malcolm A. [Univ. of Georgia, Athens, GA (United States); York, William S. [Univ. of Georgia, Athens, GA (United States)

    2015-02-17

    Most of the solar energy captured by land plants is converted into the polysaccharides (cellulose, hemicellulose, and pectin) that are the predominant components of the cell wall. These walls, which account for the bulk of plant biomass, have numerous roles in the growth and development of plants. Moreover, these walls have a major impact on human life as they are a renewable source of biomass, a source of diverse commercially useful polymers, a major component of wood, and a source of nutrition for humans and livestock. Thus, understanding the molecular mechanisms that lead to wall assembly and how cell walls and their component polysaccharides contribute to plant growth and development is essential to improve and extend the productivity and value of plant materials. The proposed research will develop and apply advanced analytical and immunological techniques to study specific changes in the structures and interactions of the hemicellulosic and pectic polysaccharides that occur during differentiation and in response to genetic modification and chemical treatments that affect wall biosynthesis. These new techniques will make it possible to accurately characterize minute amounts of cell wall polysaccharides so that subtle changes in structure that occur in individual cell types can be identified and correlated to the physiological or developmental state of the plant. Successful implementation of this research will reveal fundamental relationships between polysaccharide structure, cell wall architecture, and cell wall functions.

  6. Conditions for Two-Cell Structure in Severe Vortical Storms.

    Science.gov (United States)

    1984-02-01

    SEVERE VORTICAL STORMS by G. F. Carrier, F. E. Fendell , P. S. Feldman, and S. F. Fink TRW Space and Technology Group, Redondo Beach, CA 90278 Thi...Claification Conditions for Two-Call Structure in Severe Vortical Storms (U) 12. PERSONAL AUTHOR(S) Carrier. G. F. (Harvard U.): Fendell , F. E., Feldman...cell structure will occur. Very roughly, about half of all tropical storms ( Fendell 1974), and about one-quarter to one-half of meso- cyclones (Brooks

  7. National Assessment of Oil and Gas Project - Wind River Basin Province (035) Assessment Units Quarter-Mile Cells

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — Cell maps for each oil and gas assessment unit were created by the USGS to illustrate the degree of exploration, type of production, and distribution of production...

  8. Identified metabolic signature for assessing red blood cell unit quality is associated with endothelial damage markers and clinical outcomes

    DEFF Research Database (Denmark)

    Bordbar, Aarash; Johansson, Pär I.; Paglia, Giuseppe;

    2016-01-01

    BACKGROUND: There has been interest in determining whether older red blood cell (RBC) units have negative clinical effects. Numerous observational studies have shown that older RBC units are an independent factor for patient mortality. However, recently published randomized clinical trials have...

  9. Cell-structure and mechanical properties of closed-cell aluminum foam

    Institute of Scientific and Technical Information of China (English)

    ZHOU Yun(周芸); ZUO Xiao-qing(左孝青); SUN Jia-lin(孙加林); S.R.Nutt

    2004-01-01

    The density, cell size and structure of closed-cell aluminum foam were measured by optical microscopy and image analysis. The properties and the mechanism of compressive deformation that occur in closed-cell aluminum foam were measured and discussed. The results show that the cell size of foam with density of 0.37 mg/m3 is distributed in the range of 0.5 - 4.0 mm. The cell size of foam with density of 0.33 mg/m3 is distributed in the range of 0.5 - 5.0 mm. The cell wall thickness of both types is 0.1 - 0.3 mm. The closed-cell aluminum foam almost belongs to isotropic one, with a variation of ±15% in elastic modulus and yield strength in longitudinal and transverse direction. Under compressive loading, foam materials show inhomogeneous macroscopic deformation. The site of the onset of local plastic deformation depends on the cell structure. The shape of cell is more important than size in determining the yielding susceptibility of the cells. At early stage of deformation,the deformation is localized in narrow bands having width of one cell's diameter, and outside the bands the cell still remains the original shape. The cells within bands experience large permanent deformation. The band normals are usually within 20° of the loading axis.

  10. High quality-factor fano metasurface comprising a single resonator unit cell

    Energy Technology Data Exchange (ETDEWEB)

    Sinclair, Michael B.; Warne, Larry K.; Basilio, Lorena I.; Langston, William L.; Campione, Salvatore; Brener, Igal; Liu, Sheng

    2017-06-20

    A new monolithic resonator metasurface design achieves ultra-high Q-factors while using only one resonator per unit cell. The metasurface relies on breaking the symmetry of otherwise highly symmetric resonators to induce intra-resonator mixing of bright and dark modes (rather than inter-resonator couplings), and is scalable from the near-infrared to radio frequencies and can be easily implemented in dielectric materials. The resulting high-quality-factor Fano metasurface can be used in many sensing, spectral filtering, and modulation applications.

  11. Unit cell modeling in support of interim performance assessment for low level tank waste disposal

    Energy Technology Data Exchange (ETDEWEB)

    Kline, N.W., Westinghouse Hanford

    1996-08-01

    A unit cell model is used to simulate the base analysis case and related sensitivity cases for the interim performance assessment of low level tank waste disposal. Simulation case results are summarized in terms of fractional contaminant release rates to the vadose zone and to the water table at the unconfined aquifer. Results suggest that the crushed glass water conditioning layer at the top of the facility and the chemical retardation pad at the bottom of the facility can be important components of the facility. Results also suggest that the release rates to the water table are dominated by the release rate from the waste form.

  12. Fault imprint in clay units: magnetic fabric, structural and mineralogical signature

    Science.gov (United States)

    Moreno, Eva; Homberg, Catherine; Schnyder, Johann; Person, Alain; du Peloux1, Arthur; Dick, Pierre

    2014-05-01

    Fault-induced deformations in clay units can be difficult to decipher because strain markers are not always visible at outcrop scale or using geophysical methods. Previous studies have indicated that the anisotropy of magnetic susceptibility (ASM) provides a powerful and rapid technique to investigate tectonic deformation in clay units even when they appear quite homogenous and undeformed at the outcrop scale (Lee et al. 1990, Mattei et al. 1997). We report here a study based on ASM, structural analysis and magnetic and clay mineralogy from two boreholes (TF1 and ASM1)drilled horizontally in the Experimental Station of Tournemire of the Institute for Radiological Protection and Nuclear Safety (IRSN) in Aveyron (France). The boreholes intersect a N-S trending strike-slip fault from west to east. The ASM study indicates the evolution of the magnetic fabric from the undeformed host rock to the fault core. Also, all the fractures cutting the studied interval of the core have been measured as well as the slip vectors which are generally well preserved. In the two boreholes, the undeformed sediments outside the fault zone are characterized by an oblate fabric, a sub-vertical minimum susceptibility axis (k3) perpendicular to the bedding plane and without magnetic lineation. Within the fault zone, a tilt in the bedding plane has been observed in two boreholes TF1 and ASM1. In addition, in the TF1 core, the fault area presents a tectonic fabric characterized by a triaxial AMS ellipsoid. Moreover, the magnetic lineation increases and k3 switches from a vertical to a sub-horizontal plane. This kind of fabric has not been observed in borehole ASM1. The structural analysis of the individual fractures making the fault zone indicates a complex tectonic history with different imprint in the two fault segments cut by the two boreholes. The large majority of fractures correspond to dextral strike-slip faults but normal and reverse movements were observed and are more or less

  13. Overexpression of neurofilament H disrupts normal cell structure and function

    Science.gov (United States)

    Szebenyi, Gyorgyi; Smith, George M.; Li, Ping; Brady, Scott T.

    2002-01-01

    Studying exogenously expressed tagged proteins in live cells has become a standard technique for evaluating protein distribution and function. Typically, expression levels of experimentally introduced proteins are not regulated, and high levels are often preferred to facilitate detection. However, overexpression of many proteins leads to mislocalization and pathologies. Therefore, for normative studies, moderate levels of expression may be more suitable. To understand better the dynamics of intermediate filament formation, transport, and stability in a healthy, living cell, we inserted neurofilament heavy chain (NFH)-green fluorescent protein (GFP) fusion constructs in adenoviral vectors with tetracycline (tet)-regulated promoters. This system allows for turning on or off the synthesis of NFH-GFP at a selected time, for a defined period, in a dose-dependent manner. We used this inducible system for live cell imaging of changes in filament structure and cell shape, motility, and transport associated with increasing NFH-GFP expression. Cells with low to intermediate levels of NFH-GFP were structurally and functionally similar to neighboring, nonexpressing cells. In contrast, overexpression led to pathological alterations in both filament organization and cell function. Copyright 2002 Wiley-Liss, Inc.

  14. An interference cancellation strategy for broadcast in hierarchical cell structure

    KAUST Repository

    Yang, Yuli

    2014-12-01

    In this paper, a hierarchical cell structure is considered, where public safety broadcasting is fulfilled in a femtocell located within a macrocell. In the femtocell, also known as local cell, an access point broadcasts to each local node (LN) over an orthogonal frequency sub-band independently. Since the local cell shares the spectrum licensed to the macrocell, a given LN is interfered by transmissions of the macrocell user (MU) in the same sub-band. To improve the broadcast performance in the local cell, a novel scheme is proposed to mitigate the interference from the MU to the LN while achieving diversity gain. For the sake of performance evaluation, ergodic capacity of the proposed scheme is quantified and a corresponding closed-form expression is obtained. By comparing with the traditional scheme that suffers from the MU\\'s interference, numerical results substantiate the advantage of the proposed scheme and provide a useful tool for the broadcast design in hierarchical cell systems.

  15. The Structure of Plant Cell Walls: IV. A Structural Comparison of the Wall Hemicellulose of Cell Suspension Cultures of Sycamore (Acer PseudoPlatAnus) and of Red Kidney Bean (Phaseolus Vulgaris).

    Science.gov (United States)

    Wilder, B M; Albersheim, P

    1973-05-01

    The molecular structure and chemical properties of the hemicellulose present in the isolated cell walls of suspension cultures of sycamore (Acer pseudoplatanus) cells has recently been described by Bauer et al. (Plant Physiol. 51: 174-187). The hemicellulose of the sycamore primary cell wall is a xyloglucan. This polymer functions as an important cross-link in the structure of the cell wall; the xyloglucan is hydrogen-bonded to cellulose and covalently attached to the pectic polymers.The present paper describes the structure of a xyloglucan present in the walls and in the extracellular medium of suspension-cultured Red Kidney bean (Phaseolus vulgaris) cells and compares the structure of the bean xyloglucan with the structure of the sycamore xyloglucan. Although some minor differences were found, the basic structure of the xyloglucans in the cell walls of these distantly related species is the same. The structure is based on a repeating heptasaccharide unit which consists of four residues of beta-1, 4-linked glucose and three residues of terminal xylose linked to the 6 position of three of the glucosyl residues.

  16. Influences of the non-covalent interaction strength on reaching high solid-state order and device performance of a low bandgap polymer with axisymmetrical structural units.

    Science.gov (United States)

    Jheng, Jyun-Fong; Lai, Yu-Ying; Wu, Jhong-Sian; Chao, Yi-Hsiang; Wang, Chien-Lung; Hsu, Chain-Shu

    2013-05-07

    A high organic field-effect transistor mobility (0.29 cm(2) V(-1) s(-1) ) and bulk-heterojunction polymer solar cell performance (PCE of 6.82%) have been achieved in a low bandgap alternating copolymer consisting of axisymmetrical structural units, 5,6-difluorobenzo-2,1,3-thiadiazole. Introducing the fluorine substituents enhanced intermolecular interaction and improved the solid-state order, which consequently resulted in the highest device performances among the 2,1,3-thiadiazole-quarterthiophene based alternating copolymers.

  17. Auxiliary power unit based on a solid oxide fuel cell and fuelled with diesel

    Science.gov (United States)

    Lawrence, Jeremy; Boltze, Matthias

    An auxiliary power unit (APU) is presented that is fuelled with diesel, thermally self-sustaining, and based on a solid oxide fuel cell (SOFC). The APU is rated at 1 kW electrical, and can generate electrical power after a 3 h warm-up phase. System features include a "dry" catalytic partial oxidation (CPOX) diesel reformer, a 30 cell SOFC stack with an open cathode, and a porous-media afterburner. The APU does not require a supply of external water. The SOFC stack is an outcome of a development partnership with H.C. Starck GmbH and Fraunhofer IKTS, and is discussed in detail in an accompanying paper.

  18. Chromatin Structure in Cell Differentiation, Aging and Cancer

    NARCIS (Netherlands)

    S. Kheradmand Kia (Sima)

    2009-01-01

    textabstractChromatin is the structure that the eukaryotic genome is packaged into, allowing over a metre of DNA to fit into the small volume of the nucleus. It is composed of DNA and proteins, most of which are histones. This DNA-protein complex is the template for a number of essential cell proces

  19. The Pore Structure of Direct Methanol Fuel Cell Electrodes

    DEFF Research Database (Denmark)

    Lund, Peter Brilner

    2005-01-01

    The pore structure and morphology of direct methanol fuel cell electrodes are characterized using mercury intrusion porosimetry and scanning electron microscopy. It is found that the pore size distributions of printed primer and catalyst layers are largely dictated by the powders used to make the...

  20. Chromatin Structure in Cell Differentiation, Aging and Cancer

    NARCIS (Netherlands)

    S. Kheradmand Kia (Sima)

    2009-01-01

    textabstractChromatin is the structure that the eukaryotic genome is packaged into, allowing over a metre of DNA to fit into the small volume of the nucleus. It is composed of DNA and proteins, most of which are histones. This DNA-protein complex is the template for a number of essential cell

  1. Composite structure of wood cells in petrified wood

    Energy Technology Data Exchange (ETDEWEB)

    Nowak, Jakub [Department of Chemistry, Catholic University of Lublin, 20-718 Lublin (Poland); Florek, Marek [Department of Chemistry, Catholic University of Lublin, 20-718 Lublin (Poland); Kwiatek, Wojciech [Institute of Nuclear Physics, Department of Nuclear Spectroscopy, 31-342 Cracow (Poland); Lekki, Janusz [Institute of Nuclear Physics, Department of Nuclear Spectroscopy, 31-342 Cracow (Poland); Chevallier, Pierre [LPS, CEN Saclay et LURE, Universite Paris-Sud, Bat 209D, F-91405 Orsay (France); Zieba, Emil [Department of Chemistry, Catholic University of Lublin, 20-718 Lublin (Poland); Mestres, Narcis [Institut de Ciencia de Materials de Barcelona (ICMAB), Campus de la UAB, E-08193-Bellaterra (Spain); Dutkiewicz, E.M. [Institute of Nuclear Physics, Department of Nuclear Spectroscopy, 31-342 Cracow (Poland); Kuczumow, Andrzej [Department of Chemistry, Catholic University of Lublin, 20-718 Lublin (Poland)

    2005-04-28

    Special kinds of petrified wood of complex structure were investigated. All the samples were composed of at least two different inorganic substances. The original cell structure was preserved in each case. The remnants of the original biological material were detected in some locations, especially in the cell walls. The complex inorganic structure was superimposed on the remnant organic network. The first inorganic component was located in the lumena (l.) of the cells while another one in the walls (w.) of the cells. The investigated arrangements were as follows: calcite (l.)-goethite-hematite (w.)-wood from Dunarobba, Italy; pyrite (l.)-calcite (w.)-wood from Lukow, Poland; goethite (l.)-silica (w.)-wood from Kwaczala, Poland. The inorganic composition was analysed and spatially located by the use of three spectral methods: electron microprobe, X-ray synchrotron-based microprobe, {mu}-PIXE microprobe. The accurate mappings presenting 2D distribution of the chemical species were presented for each case. Trace elements were detected and correlated with the distribution of the main elements. In addition, the identification of phases was done by the use of {mu}-Raman and {mu}-XRD techniques for selected and representative points. The possible mechanisms of the described arrangements are considered. The potential synthesis of similar structures and their possible applications are suggested.

  2. Structure and dynamics of metalloproteins in live cells.

    Science.gov (United States)

    Cook, Jeremy D; Penner-Hahn, James E; Stemmler, Timothy L

    2008-01-01

    X-ray absorption spectroscopy (XAS) has emerged as one of the premier tools for investigating the structure and dynamic properties of metals in cells and in metal containing biomolecules. Utilizing the high flux and broad energy range of X-rays supplied by synchrotron light sources, one can selectively excite core electronic transitions in each metal. Spectroscopic signals from these electronic transitions can be used to dissect the chemical architecture of metals in cells, in cellular components, and in biomolecules at varying degrees of structural resolution. With the development of ever-brighter X-ray sources, X-ray methods have grown into applications that can be utilized to provide both a cellular image of the relative distribution of metals throughout the cell as well as a high-resolution picture of the structure of the metal. As these techniques continue to grow in their capabilities and ease of use, so too does the demand for their application by chemists and biochemists interested in studying the structure and dynamics of metals in cells, in cellular organelles, and in metalloproteins.

  3. Chromatin Structure in Cell Differentiation, Aging and Cancer

    NARCIS (Netherlands)

    S. Kheradmand Kia (Sima)

    2009-01-01

    textabstractChromatin is the structure that the eukaryotic genome is packaged into, allowing over a metre of DNA to fit into the small volume of the nucleus. It is composed of DNA and proteins, most of which are histones. This DNA-protein complex is the template for a number of essential cell proces

  4. Spherical TiO2 aggregates with different building units for dye-sensitized solar cells.

    Science.gov (United States)

    Liu, Zhaohui; Su, Xunjia; Hou, Genliang; Bi, Song; Xiao, Zhou; Jia, Haipeng

    2013-09-07

    Tailoring the architectures of spherical TiO2 aggregates is crucial to obtain superior photovoltaic properties and promote their application in dye-sensitized solar cells (DSSCs). Herein, we synthesized spherical TiO2 aggregates using different building units, including nanocrystallites, nanorods, nanosheets, and nanotubes, via a hydrothermal method, and studied the effect of the building units on the performances of DSSCs. The aggregates assembled by uniform nanosheet and nanotube building units were synthesized with the use of spherical TiO2 nanorod aggregates as titanium sources in an alkaline hydrothermal reaction. Compared with TiO2 nanoparticles, the spherical TiO2 aggregates possess higher surface area, more efficient light scattering ability, and better electron transport properties. Among the four types of spherical TiO2 aggregates; the nanorod, nanotube, and nanosheet aggregates demonstrate better electron transport properties than the nanocrystallite aggregates; the nanotube and nanosheet aggregates exhibit more efficient light scattering than the nanocrystallite and nanorod aggregates; and the nanotube aggregates show the highest surface area. Thus the DSSC based on nanotube aggregates exhibited the highest energy conversion efficiency of 7.48%, which is 16.0%, 9.7%, and 19.5% higher than those of the DSSCs based on the nanosheet, nanorod, and nanocrystallite aggregates, respectively.

  5. Patterns of population structure for inshore bottlenose dolphins along the eastern United States.

    Science.gov (United States)

    Richards, Vincent P; Greig, Thomas W; Fair, Patricia A; McCulloch, Stephen D; Politz, Christine; Natoli, Ada; Driscoll, Carlos A; Hoelzel, A Rus; David, Victor; Bossart, Gregory D; Lopez, Jose V

    2013-01-01

    Globally distributed, the bottlenose dolphin (Tursiops truncatus) is found in a range of offshore and coastal habitats. Using 15 microsatellite loci and mtDNA control region sequences, we investigated patterns of genetic differentiation among putative populations along the eastern US shoreline (the Indian River Lagoon, Florida, and Charleston Harbor, South Carolina) (microsatellite analyses: n = 125, mtDNA analyses: n = 132). We further utilized the mtDNA to compare these populations with those from the Northwest Atlantic, Gulf of Mexico, and Caribbean. Results showed strong differentiation among inshore, alongshore, and offshore habitats (ФST = 0.744). In addition, Bayesian clustering analyses revealed the presence of 2 genetic clusters (populations) within the 250 km Indian River Lagoon. Habitat heterogeneity is likely an important force diversifying bottlenose dolphin populations through its influence on social behavior and foraging strategy. We propose that the spatial pattern of genetic variation within the lagoon reflects both its steep longitudinal transition of climate and also its historical discontinuity and recent connection as part of Intracoastal Waterway development. These findings have important management implications as they emphasize the role of habitat and the consequence of its modification in shaping bottlenose dolphin population structure and highlight the possibility of multiple management units existing in discrete inshore habitats along the entire eastern US shoreline.

  6. A Single-Unit Design Structure and Gender Differences in the Swimming World Championships

    Science.gov (United States)

    Pushkar, Svetlana; Issurin, Vladimir B.; Verbitsky, Oleg

    2014-01-01

    Four 50 meter male/female finals - the freestyle, butterfly, breaststroke, and backstroke - swum during individual events at the Swimming World Championships (SWCs) can be defined in four clusters. The aim of the present study was to use a single-unit design structure, in which the swimmer was defined at only one scale, to evaluate gender differences in start reaction times among elite swimmers in 50 m events. The top six male and female swimmers in the finals of four swimming stroke final events in six SWCs were analyzed. An unpaired t-test was used. The p-values were evaluated using Neo-Fisherian significance assessments (Hurlbert and Lombardi, 2012). For the freestyle, gender differences in the start reaction times were positively identified for five of the six SWCs. For the backstroke, gender differences in the start reaction times could be dismissed for five of the six SWCs. For both the butterfly and breaststroke, gender differences in the start reaction times yielded inconsistent statistical differences. Pooling all swimmers together (df = 286) showed that an overall gender difference in the start reaction times could be positively identified: p = 0.00004. The contrast between the gender differences in start reaction times between the freestyle and backstroke may be associated with different types of gender adaptations to swimming performances. When the natural groupings of swimming stroke final events were ignored, sacrificial pseudoreplication occurred, which may lead to erroneous statistical differences. PMID:25414754

  7. A Single-Unit Design Structure and Gender Differences in the Swimming World Championships

    Directory of Open Access Journals (Sweden)

    Pushkar Svetlana

    2014-10-01

    Full Text Available Four 50 meter male/female finals - the freestyle, butterfly, breaststroke, and backstroke - swum during individual events at the Swimming World Championships (SWCs can be defined in four clusters. The aim of the present study was to use a single-unit design structure, in which the swimmer was defined at only one scale, to evaluate gender differences in start reaction times among elite swimmers in 50 m events. The top six male and female swimmers in the finals of four swimming stroke final events in six SWCs were analyzed. An unpaired t-test was used. The p-values were evaluated using Neo-Fisherian significance assessments (Hurlbert and Lombardi, 2012. For the freestyle, gender differences in the start reaction times were positively identified for five of the six SWCs. For the backstroke, gender differences in the start reaction times could be dismissed for five of the six SWCs. For both the butterfly and breaststroke, gender differences in the start reaction times yielded inconsistent statistical differences. Pooling all swimmers together (df = 286 showed that an overall gender difference in the start reaction times could be positively identified: p = 0.00004. The contrast between the gender differences in start reaction times between the freestyle and backstroke may be associated with different types of gender adaptations to swimming performances. When the natural groupings of swimming stroke final events were ignored, sacrificial pseudoreplication occurred, which may lead to erroneous statistical differences

  8. Patterns of Population Structure for Inshore Bottlenose Dolphins along the Eastern United States

    Science.gov (United States)

    2013-01-01

    Globally distributed, the bottlenose dolphin (Tursiops truncatus) is found in a range of offshore and coastal habitats. Using 15 microsatellite loci and mtDNA control region sequences, we investigated patterns of genetic differentiation among putative populations along the eastern US shoreline (the Indian River Lagoon, Florida, and Charleston Harbor, South Carolina) (microsatellite analyses: n = 125, mtDNA analyses: n = 132). We further utilized the mtDNA to compare these populations with those from the Northwest Atlantic, Gulf of Mexico, and Caribbean. Results showed strong differentiation among inshore, alongshore, and offshore habitats (ФST = 0.744). In addition, Bayesian clustering analyses revealed the presence of 2 genetic clusters (populations) within the 250 km Indian River Lagoon. Habitat heterogeneity is likely an important force diversifying bottlenose dolphin populations through its influence on social behavior and foraging strategy. We propose that the spatial pattern of genetic variation within the lagoon reflects both its steep longitudinal transition of climate and also its historical discontinuity and recent connection as part of Intracoastal Waterway development. These findings have important management implications as they emphasize the role of habitat and the consequence of its modification in shaping bottlenose dolphin population structure and highlight the possibility of multiple management units existing in discrete inshore habitats along the entire eastern US shoreline. PMID:24129993

  9. The US business cycle: power law scaling for interacting units with complex internal structure

    Science.gov (United States)

    Ormerod, Paul

    2002-11-01

    In the social sciences, there is increasing evidence of the existence of power law distributions. The distribution of recessions in capitalist economies has recently been shown to follow such a distribution. The preferred explanation for this is self-organised criticality. Gene Stanley and colleagues propose an alternative, namely that power law scaling can arise from the interplay between random multiplicative growth and the complex structure of the units composing the system. This paper offers a parsimonious model of the US business cycle based on similar principles. The business cycle, along with long-term growth, is one of the two features which distinguishes capitalism from all previously existing societies. Yet, economics lacks a satisfactory theory of the cycle. The source of cycles is posited in economic theory to be a series of random shocks which are external to the system. In this model, the cycle is an internal feature of the system, arising from the level of industrial concentration of the agents and the interactions between them. The model-in contrast to existing economic theories of the cycle-accounts for the key features of output growth in the US business cycle in the 20th century.

  10. The structure of convective rain cells at mid-latitudes

    Directory of Open Access Journals (Sweden)

    N. Rebora

    2006-01-01

    Full Text Available Rain cells are structures which represent an important component of convective precipitation and a study of their properties represents a necessary step both towards improved stochastic models of small-scale precipitation and for the verification of deterministic high resolution local-area models. The case of intense convective precipitation in the tropics has been analysed in a recent study (von Hardenberg et al., 2003. Here we extend the analysis to mid-latitudes and we present results on the structure of convective rain cells observed by radar measurements in Italy. In particular we consider the average shape of precipitation cells and its dependence on radar resolution and the distributions of ellipticities.

  11. Application of Three Unit-Cells Models on Mechanical Analysis of 3D Five-Directional and Full Five-Directional Braided Composites

    Science.gov (United States)

    Zhang, Chao; Xu, Xiwu; Chen, Kang

    2013-10-01

    As new lightweight textile material, 3D five directional and full five directional braided composites (5DBC and F5DBC) have tremendous potential applications in the aerospace industry. Before they are used in primary loading-bearing structures, a rational characterization of their mechanical properties is essential. In this paper, three types of unit-cell models corresponding to the interior, surface and corner regions of 5DBC and F5DBC are proposed. By introducing the reasonable boundary conditions, the effective stiffness properties of these two materials are predicted and compared by the three unit-cells models. The detailed mechanical response characteristic of the three unit-cell models is presented and analyzed in various loading cases. Numerical results show good agreement with experiment data, thus validates the proposed simulation method. Moreover, a parametric study is carried out for analyzing the effects of braiding angle and fiber volume fraction on the elastic properties of 5DBC and F5DBC. The obtained results can help designers to optimize the braided composite structures.

  12. Picometer registration of zinc impurity states in Bi2Sr2CaCu2O8+delta for phase determination in intra-unit-cell Fourier transform STM

    OpenAIRE

    Hamidian, M. H.; Firmo, I. A.; Fujita, K.; Mukhopadhyay, S.(Saha Institute of Nuclear Physics, Kolkata, India); Orenstein, J. W.; Eisaki, H.; Uchida, S.; Lawler, M. J; Kim, E-A; Davis, J. C.

    2012-01-01

    Direct visualization of electronic-structure symmetry within each crystalline unit cell is a new technique for complex electronic matter research (Lawler et al 2010 Nature 466 347-51, Schmidt et al 2011 New J. Phys. 13 065014, Fujita K et al 2012 J. Phys. Soc. Japan 81 011005). By studying the Bragg peaks in Fourier transforms of electronic structure images and particularly by resolving both the real and imaginary components of the Bragg amplitudes, distinct types of intra-unit-cell symmetry ...

  13. Cell wall structure and function in lactic acid bacteria.

    Science.gov (United States)

    Chapot-Chartier, Marie-Pierre; Kulakauskas, Saulius

    2014-08-29

    The cell wall of Gram-positive bacteria is a complex assemblage of glycopolymers and proteins. It consists of a thick peptidoglycan sacculus that surrounds the cytoplasmic membrane and that is decorated with teichoic acids, polysaccharides, and proteins. It plays a major role in bacterial physiology since it maintains cell shape and integrity during growth and division; in addition, it acts as the interface between the bacterium and its environment. Lactic acid bacteria (LAB) are traditionally and widely used to ferment food, and they are also the subject of more and more research because of their potential health-related benefits. It is now recognized that understanding the composition, structure, and properties of LAB cell walls is a crucial part of developing technological and health applications using these bacteria. In this review, we examine the different components of the Gram-positive cell wall: peptidoglycan, teichoic acids, polysaccharides, and proteins. We present recent findings regarding the structure and function of these complex compounds, results that have emerged thanks to the tandem development of structural analysis and whole genome sequencing. Although general structures and biosynthesis pathways are conserved among Gram-positive bacteria, studies have revealed that LAB cell walls demonstrate unique properties; these studies have yielded some notable, fundamental, and novel findings. Given the potential of this research to contribute to future applied strategies, in our discussion of the role played by cell wall components in LAB physiology, we pay special attention to the mechanisms controlling bacterial autolysis, bacterial sensitivity to bacteriophages and the mechanisms underlying interactions between probiotic bacteria and their hosts.

  14. Polymer nanofibrous structures: Fabrication, biofunctionalization, and cell interactions.

    Science.gov (United States)

    Beachley, Vince; Wen, Xuejun

    2010-07-01

    Extracellular matrix fibers (ECM) such as collagen, elastin, and keratin provide biological and physical support for cell attachment, proliferation, migration, differentiation and ultimately cell fate. Therefore, ECM fibers are an important component in tissue and organ development and regeneration. Meanwhile, polymer nanofibers could play the same critical role in tissue regeneration process. Fibrous structures can be fabricated from a variety of materials and methods with diameters ranging throughout the size scale where cells can sense individual fibers (several nanometers to several microns). Polymer nanofiber scaffolds can be designed in a way that predictably modulates a variety of important cell behaviors towards a desired overall function. The nanofibrous topography itself, independent of the fiber material, has demonstrated the potential to modulate cell behaviors desirable in tissue engineering such as: unidirectional alignment; increased viability, attachment, and ECM production; guided migration; and controlled differentiation. The versatility of polymer nanofibers for functionalization with biomolecules opens the door to vast opportunities for the design of tissue engineering scaffolds with even greater control over cell incorporation and function. Despite the promise of polymer nanofibers as tissue engineering scaffolds there have been few clinically relevant successes because no single fabrication technique currently combines control over structural arrangement, material composition, and biofunctionalization, while maintaining reasonable cost and yield. Promising strategies are currently being investigated to allow for the fabrication of optimal polymer nanofiber tissue engineering scaffolds with the goal of treating damaged and degenerated tissues in a clinical setting.

  15. Polymer nanofibrous structures: Fabrication, biofunctionalization, and cell interactions

    Science.gov (United States)

    Beachley, Vince; Wen, Xuejun

    2010-01-01

    Extracellular matrix fibers (ECM) such as collagen, elastin, and keratin provide biological and physical support for cell attachment, proliferation, migration, differentiation and ultimately cell fate. Therefore, ECM fibers are an important component in tissue and organ development and regeneration. Meanwhile, polymer nanofibers could play the same critical role in tissue regeneration process. Fibrous structures can be fabricated from a variety of materials and methods with diameters ranging throughout the size scale where cells can sense individual fibers (several nanometers to several microns). Polymer nanofiber scaffolds can be designed in a way that predictably modulates a variety of important cell behaviors towards a desired overall function. The nanofibrous topography itself, independent of the fiber material, has demonstrated the potential to modulate cell behaviors desirable in tissue engineering such as: unidirectional alignment; increased viability, attachment, and ECM production; guided migration; and controlled differentiation. The versatility of polymer nanofibers for functionalization with biomolecules opens the door to vast opportunities for the design of tissue engineering scaffolds with even greater control over cell incorporation and function. Despite the promise of polymer nanofibers as tissue engineering scaffolds there have been few clinically relevant successes because no single fabrication technique currently combines control over structural arrangement, material composition, and biofunctionalization, while maintaining reasonable cost and yield. Promising strategies are currently being investigated to allow for the fabrication of optimal polymer nanofiber tissue engineering scaffolds with the goal of treating damaged and degenerated tissues in a clinical setting. PMID:20582161

  16. An innovative approach of structural instabilities in tetragonal tungsten bronze crystals through the concept of rigid unit modes

    OpenAIRE

    Smirnov, Mikhail; Saint-Grégoire, Pierre

    2013-01-01

    Tetragonal tungsten bronze (TTB) oxides are one of the most important classes of ferroelectrics. Many of these framework structures undergo ferroelastic transformations related to octahedron tilting deformations. Such tilting deformations are closely related to the Rigid Unit Modes (RUMs). This paper discusses the whole set of RUMs in an ideal TTB lattice and possible crystal structures which can emerge owing to the condensation of some of them. Analysis of available experimental data for the...

  17. Synthesis, Crystal Structure and Photophysical Properties of a Novel Molecule Containing a Triarylamine and an Oxadiazole Units

    Institute of Scientific and Technical Information of China (English)

    YU,Hai-Tao(于海涛); ZHANG,Wan-Xuan(张万轩); BAI,Dong-Ren(白东仁); MENG,Ji-Ben(孟继本)

    2002-01-01

    2-{ 3-[2-(4-N, N-Di-p-tolylaminophenyl )ethenyl ] phenyl }-5- (4-bromophenyl)-1,3,4-oxadiazole (1) containing triarylamine and 2,5-diaryl-1,3,4-oxadiazole units was prepared by HornerWitting reactions. The structure of the compound was confirmed by1H NMR, IR, MS and elemental analyses. The crystal structure of 1 was determined by X-ray diffraction analysis.UV absorption spectra and photoluminescent spectra were measured.

  18. Computational study of liquid-gas cross-flow within structured packing cells

    Science.gov (United States)

    Lavalle, Gianluca; Lucquiaud, Mathieu; Valluri, Prashant

    2016-11-01

    Absorption columns used in the carbon capture processes and filled with structured packings are crucial to foster the exchanges and the transfers between the absorber liquid and the flue gas. However, flow reversal can occur under special flow conditions, resulting in a dramatic drop of the technological performances. We investigate numerically the liquid-gas pattern within a cross-flow packing cell. The cell is a complex geometry with two connected channels, where the two phases flow co- or counter-currently. We show that an increase of both the gas speed and the liquid load leads to an increase of the pressure drop. Particular focus is also given to the analysis of flow repartition and flooding delay. We reveal that tilting the unit cell helps to delay the flooding and extends the operational capability. The pressure drop of the cross-flow unit cell is also compared to the Mellapak packing which is widely used in carbon capture applications. Finally, we support this study by performing numerical simulations on simpler geometries by means of a low-dimensional film-gas model, in order to investigate the two-phase dynamics and predict the flooding onset with a low computational cost. The authors gratefully acknowledge EPSRC Grant No. EP/M001482/1.

  19. Fuel cell collaboration in the United States. A report to the Danish Partnership for Hydrogen and Fuel Cells

    Energy Technology Data Exchange (ETDEWEB)

    2011-08-15

    The purpose of this report is to provide members of the Danish Partnership for Hydrogen and Fuel Cells with information regarding collaborative opportunities in the United States. The report is designed to provide an overview of key issues and activities and to provide guidance on strategies for finding U.S. research and commercial partners and gaining access to the U.S. market. Section 1 of this report provides an overview of the key drivers of policy at the federal and state government levels regarding hydrogen and fuel cell technologies and provides a perspective of the U.S. industry and key players. It also suggests three general pathways for accessing U.S. opportunities: enhancing visibility; developing vendor relationships; and establishing a formal presence in the U.S. The next sections summarize focus areas for commercial and research activity that currently are of the greatest interest in the U.S. Section 2 describes major programs within the federal government and national laboratories, and discusses various methods for identifying R and D funding opportunities, with an overview of federal acquisition regulations. Section 3 reviews the efforts of several state governments engaging the fuel cell industry as an economic driver and presents an overview of acquisition at the state level. Section 4 discusses university research and development (R and D) and university-industry partnerships. There are 12 appendices attached to the report. These appendices provide more detailed information regarding the key federal government agencies involved in fuel cells and hydrogen, state-specific policies and activities, national laboratories and universities, and other information regarding the fuel cell and hydrogen industry in the U.S. (Author)

  20. Two new hexacoordinated coordination polymers of cadmium(II) containing bridging units only: Syntheses, structures and molecular properties

    Indian Academy of Sciences (India)

    DIPU SUTRADHAR; HABIBAR CHOWDHURY; SUSHOVAN KONER; SUBHASIS ROY; BARINDRA KUMAR GHOSH

    2016-09-01

    The syntheses, characterizations and structures of a neutral 2D coordination polymer [Cd(bnzd)(NCS)₂]n (1) and a polycationic 3D coordination polymer isolated as perchlorate salt [Cd(bnzd)₃]n(ClO₄)₂n (2) (bnzd = benzidine) are described. X-ray structural analyses reveal that each hexacoordinated cadmium(II) center in 1 adopts a distorted octahedral geometry with a CdN₄S₂ chromophore bound by two N atoms of two different bnzd units and two N and two S atoms of symmetric doubly bridged end-toend NCS− units extended in a 2D sheet. Six N atoms of six different bridged bnzd units are bonded to each cadmium(II) in 2 in a non-ended fashion affording a 3D network structure. In the crystalline state, each 2D sheet structure in 1 is further stabilized by π· · ·π interaction which in turn affords a 3D network structure through multiple intermolecular N-H· · · S hydrogen bonds. On the other hand, the 3D network structure in 2 is stabilized by weak intermolecular N-H· · ·O hydrogen bonds and C-H· · ·π interactions. Bnzd, 1 and 2 display intraligand 1(π-π*) fluorescence in DMF solution at room temperature.

  1. Influence of surrounding structures upon the aerodynamic and acoustic performance of the outdoor unit of a split air-conditioner

    Science.gov (United States)

    Wu, Chengjun; Liu, Jiang; Pan, Jie

    2014-07-01

    DC-inverter split air-conditioner is widely used in Chinese homes as a result of its high-efficiency and energy-saving. Recently, the researches on its outdoor unit have focused on the influence of surrounding structures upon the aerodynamic and acoustic performance, however they are only limited to the influence of a few parameters on the performance, and practical design of the unit requires more detailed parametric analysis. Three-dimensional computational fluid dynamics(CFD) and computational aerodynamic acoustics(CAA) simulation based on FLUENT solver is used to study the influence of surrounding structures upon the aforementioned properties of the unit. The flow rate and sound pressure level are predicted for different rotating speed, and agree well with the experimental results. The parametric influence of three main surrounding structures(i.e. the heat sink, the bell-mouth type shroud and the outlet grille) upon the aerodynamic performance of the unit is analyzed thoroughly. The results demonstrate that the tip vortex plays a major role in the flow fields near the blade tip and has a great effect on the flow field of the unit. The inlet ring's size and throat's depth of the bell-mouth type shroud, and the through-flow area and configuration of upwind and downwind sections of the outlet grille are the most important factors that affect the aerodynamic performance of the unit. Furthermore, two improved schemes against the existing prototype of the unit are developed, which both can significantly increase the flow rate more than 6 %(i.e. 100 m3·h-1) at given rotating speeds. The inevitable increase of flow noise level when flow rate is increased and the advantage of keeping a lower rotating speed are also discussed. The presented work could be a useful guideline in designing the aerodynamic and acoustic performance of the split air-conditioner in engineering practice.

  2. Population structure of the emerging plant pathogen Phytophthora ramorum on the west coast of the United States

    Science.gov (United States)

    S. Prospero; E.M. Hansen; N.J. Grünwald; J. Britt; L.M. Winton.

    2009-01-01

    Phytophthora ramorum is a devastating pathogen in native forests in California and southwestern Oregon and in nursery crops in California, Oregon and Washington. In this study we analyzed the population structure of P. ramorum in the west coast (CA, OR, and WA) of the United States by screening 579 isolates recovered...

  3. Latar as the Central Point of Houses Group Unit: Identifiability for Spatial Structure in Kasongan, Yogyakarta, Indonesia

    Directory of Open Access Journals (Sweden)

    T. Yoyok Wahyu Subroto

    2012-05-01

    Full Text Available The massive spatial expansion of the city into the rural area in recent decades has caused such problems as related to the spatial exploitation in villages surrounding. This raises a question of whether the open space change into land coverage building may have a spatial structure implication on settlement growth and evolution process in the villages surrounding. This paper reports a case study of Kasongan village in Bantul regency, Yogyakarta, Indonesia in between 1973-2010 in which the problem refers to the discussion of spatial structure is rarely addressed especially in village’s settlement growth and evolution analysis. The bound axis which consists of 4 (four quadrants and one intersection refers to the reference axes in a Cartesian Coordinate System (CCS is used to analyze the setting of the houses group unit around 4 areas/ quadrants. Through such spatial process analysis by means spatial structure approach, the continuity of latar (yard, in the central of houses group unit is detected. There is finding from this research that the latar which exists in ‘the central point’ of houses group unit in Kasongan during 4 decades significantly becomes the prominent factor of the basic spatial structure. It composes the houses group unit in Kasongan.

  4. "The Great Gatsby" and the Twenties: The Notion of Structure as a Unifying Device in an Interdisciplinary Unit.

    Science.gov (United States)

    Peale, Lydia

    An effective, 3-week unit on the 1920's in America, inspired by a reading of "The Great Gatsby," is designed around the idea of structure in history, government, literature, and writing. It has the following aims for students: (1) to understand the history of the 1920s, (2) to see literature as a creative shaping of the experience of the time, (3)…

  5. Carbon Mitigation Impacts of Increased Softwood Lumber and Structural Panel Use for Nonresidential Construction in the United States

    Science.gov (United States)

    Prakash Nepal; Kenneth E. Skog; David B. McKeever; Richard D. Bergman; Karen L. Abt; Robert C. Abt

    2016-01-01

    More wood use in the United States to construct low-rise nonresidential (NR) buildings would increase consumption and production of softwood (SW) lumber, engineered wood products, and structural and nonstructural wood panels. Using a consequential life-cycle analysis, we estimated the change in net CO2 emissions thatwould be caused by increased...

  6. Occupational and Qualification Structures in the Field of Environmental Protection in the Metal and Chemical Industries in the United Kingdom.

    Science.gov (United States)

    European Centre for the Development of Vocational Training, Berlin (Germany).

    A study analyzed the occupational structure and qualifications associated with the field of environmental protection in the metal and chemical industries in the United Kingdom. The analysis included nine case studies based on interviews with firms in the chemicals and metals sectors. Information was gathered within an analytical framework that…

  7. STREAMLINED APPROACH FOR ENVIRONMENTAL RESTORATION PLAN FOR CORRECTIVE ACTION UNIT 116: AREA 25 TEST CELL C FACILITYNEVADA TEST SITE, NEVADA

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2006-07-01

    This Streamlined Approach for Environmental Restoration Plan identifies the activities required for the closure of Corrective Action Unit 116, Area 25 Test Cell C Facility. The Test Cell C Facility is located in Area 25 of the Nevada Test Site approximately 25 miles northwest of Mercury, Nevada.

  8. Nano-Structured Proton Exchange Membrane for Fuel Cell

    Institute of Scientific and Technical Information of China (English)

    Wu Chien-Suen; Lin Fan-Yen; Chu Peter P

    2005-01-01

    @@ 1Introduction Nano-structured materials are characterized by long range ordering of the nano-dimensioned quantum dot units. They have been found to deliver substantially different (electric, optical, magnetic and physical) properties from that of the bulk. The differences are mainly due to the increases of surface charge with large fraction of grain boundaries, and the periodical potential field created by the ordered nano-domains. Specifically,the issues considered in "nano ionics" are the degree of interaction, the charge distribution on the interfaces where they become obvious in ionic properties and thermodynamics such as mobility of charge carriers. Major efforts in this direction are focused on:

  9. Impact of the irregular microgeometry of polyurethane foam on the macroscopic acoustic behavior predicted by a unit-cell model.

    Science.gov (United States)

    Doutres, O; Ouisse, M; Atalla, N; Ichchou, M

    2014-10-01

    This paper deals with the prediction of the macroscopic sound absorption behavior of highly porous polyurethane foams using two unit-cell microstructure-based models recently developed by Doutres, Atalla, and Dong [J. Appl. Phys. 110, 064901 (2011); J. Appl. Phys. 113, 054901 (2013)]. In these models, the porous material is idealized as a packing of a tetrakaidecahedra unit-cell representative of the disordered network that constitutes the porous frame. The non-acoustic parameters involved in the classical Johnson-Champoux-Allard model (i.e., porosity, airflow resistivity, tortuosity, etc.) are derived from characteristic properties of the unit-cell and semi-empirical relationships. A global sensitivity analysis is performed on these two models in order to investigate how the variability associated with the measured unit-cell characteristics affects the models outputs. This allows identification of the possible limitations of a unit-cell micro-macro approach due to microstructure irregularity. The sensitivity analysis mainly shows that for moderately and highly reticulated polyurethane foams, the strut length parameter is the key parameter since it greatly impacts three important non-acoustic parameters and causes large uncertainty on the sound absorption coefficient even if its measurement variability is moderate. For foams with a slight inhomogeneity and anisotropy, a micro-macro model associated to cell size measurements should be preferred.

  10. Oligomeric structure and minimal functional unit of the electrogenic sodium bicarbonate cotransporter NBCe1-A.

    Science.gov (United States)

    Kao, Liyo; Sassani, Pakan; Azimov, Rustam; Pushkin, Alexander; Abuladze, Natalia; Peti-Peterdi, Janos; Liu, Weixin; Newman, Debra; Kurtz, Ira

    2008-09-26

    The electrogenic sodium bicarbonate cotransporter NBCe1-A mediates the basolateral absorption of sodium and bicarbonate in the proximal tubule. In this study the oligomeric state and minimal functional unit of NBCe1-A were investigated. Wild-type (wt) NBCe1-A isolated from mouse kidney or heterologously expressed in HEK293 cells was predominantly in a dimeric state as was shown using fluorescence energy transfer, pulldown, immunoprecipitation, cross-linking experiments, and nondenaturing perfluorooctanoate-PAGE. NBCe1-A monomers were found to be covalently linked by S-S bonds. When each of the 15 native cysteine residues were individually removed on a wt-NBCe1-A backbone, dimerization of the cotransporter was not affected. In experiments involving multiple native cysteine residue removal, both Cys(630) and Cys(642) in extracellular loop 3 were shown to mediate S-S bond formation between NBCe1-A monomers. When native NBCe1-A cysteine residues were individually reintroduced into a cysteineless NBCe1-A mutant backbone, the finding that a Cys(992) construct that lacked S-S bonds functioned normally indicated that stable covalent linkage of NBCe1-A monomers was not a necessary requirement for functional activity of the cotransporter. Studies using concatameric constructs of wt-NBCe1-A, whose activity is resistant to methanesulfonate reagents, and an NBCe1-A(T442C) mutant, whose activity is completely inhibited by methanesulfonate reagents, confirmed that NBCe1-A monomers are functional. Our results demonstrate that wt-NBCe1-A is predominantly a homodimer, dependent on S-S bond formation that is composed of functionally active monomers.

  11. The structure of cell-matrix adhesions: the new frontier.

    Science.gov (United States)

    Hanein, Dorit; Horwitz, Alan Rick

    2012-02-01

    Adhesions between the cell and the extracellular matrix (ECM) are mechanosensitive multi-protein assemblies that transmit force across the cell membrane and regulate biochemical signals in response to the chemical and mechanical environment. These combined functions in force transduction, signaling and mechanosensing contribute to cellular phenotypes that span development, homeostasis and disease. These adhesions form, mature and disassemble in response to actin organization and physical forces that originate from endogenous myosin activity or external forces by the extracellular matrix. Despite advances in our understanding of the protein composition, interactions and regulation, our understanding of matrix adhesion structure and organization, how forces affect this organization, and how these changes dictate specific signaling events is limited. Insights across multiple structural levels are acutely needed to elucidate adhesion structure and ultimately the molecular basis of signaling and mechanotransduction. Here we describe the challenges and recent advances and prospects for unraveling the structure of cell-matrix adhesions and their response to force. Copyright © 2011 Elsevier Ltd. All rights reserved.

  12. Structural analysis of red blood cell aggregates under shear flow.

    Science.gov (United States)

    Chesnutt, J K W; Marshall, J S

    2010-03-01

    A set of measures of red blood cell (RBC) aggregates are developed and applied to examine the aggregate structure under plane shear and channel flows. Some of these measures are based on averages over the set of red blood cells which are in contact with each other at a given time. Other measures are developed by first fitting an ellipse to the planar projection of the aggregate, and then examining the area and aspect ratio of the fit ellipse as well as the orientations of constituent RBCs with respect to the fit ellipse axes. The aggregate structural measures are illustrated using a new mesoscale computational model for blood cell transport, collision and adhesion. The sensitivity of this model to change in adhesive surface energy density and shear rate on the aggregate structure is examined. It is found that the mesoscale model predictions exhibit reasonable agreement with experimental and theoretical data for blood flow in plane shear and channel flows. The new structural measures are used to examine the differences between predictions of two- and three-dimensional computations of the aggregate formation, showing that two-dimensional computations retain some of the important aspects of three-dimensional computations.

  13. Structural and wetting properties of fuel cell components

    Science.gov (United States)

    Volfkovich, Yu. M.; Sosenkin, V. E.; Bagotsky, V. S.

    The operation of proton exchange membrane (PEMFC) and direct methanol fuel cells (DMFC) is connected with the flow of different gaseous and liquid components in the cell's membrane-electrode assembly (MEA). The structural and wetting properties of different components of the MEA influence the rate and direction of these flows and hence the fuel cell's efficiency. For a better understanding of the mechanism of all processes influencing the fuel cell efficiency, for a mathematical modelling of these processes, and for a possibility of their optimization, a detailed knowledge of the geometrical structure and wetting properties of all MEA components is necessary. This review describes the results of such investigations performed mainly by using the method of standard contact porosimetry (MSCP). This method gives the possibility to receive information on multicomponent porous and powdered materials hitherto not accessible, viz. their wetting and swelling properties, pore corrugation, and also isotherms of capillary pressure and bond energy. Measurements of MEA components by this method can be performed under exactly the same conditions (temperature, compression degree, contact with water, etc.) as those existing in real fuel cells.

  14. Acute Cardiovascular Care Association Position Paper on Intensive Cardiovascular Care Units: An update on their definition, structure, organisation and function.

    Science.gov (United States)

    Bonnefoy-Cudraz, Eric; Bueno, Hector; Casella, Gianni; De Maria, Elia; Fitzsimons, Donna; Halvorsen, Sigrun; Hassager, Christian; Iakobishvili, Zaza; Magdy, Ahmed; Marandi, Toomas; Mimoso, Jorge; Parkhomenko, Alexander; Price, Susana; Rokyta, Richard; Roubille, Francois; Serpytis, Pranas; Shimony, Avi; Stepinska, Janina; Tint, Diana; Trendafilova, Elina; Tubaro, Marco; Vrints, Christiaan; Walker, David; Zahger, Doron; Zima, Endre; Zukermann, Robert; Lettino, Maddalena

    2017-08-01

    Acute cardiovascular care has progressed considerably since the last position paper was published 10 years ago. It is now a well-defined, complex field with demanding multidisciplinary teamworking. The Acute Cardiovascular Care Association has provided this update of the 2005 position paper on acute cardiovascular care organisation, using a multinational working group. The patient population has changed, and intensive cardiovascular care units now manage a large range of conditions from those simply requiring specialised monitoring, to critical cardiovascular diseases with associated multi-organ failure. To describe better intensive cardiovascular care units case mix, acuity of care has been divided into three levels, and then defining intensive cardiovascular care unit functional organisation. For each level of intensive cardiovascular care unit, this document presents the aims of the units, the recommended management structure, the optimal number of staff, the need for specially trained cardiologists and cardiovascular nurses, the desired equipment and architecture, and the interaction with other departments in the hospital and other intensive cardiovascular care units in the region/area. This update emphasises cardiologist training, referring to the recently updated Acute Cardiovascular Care Association core curriculum on acute cardiovascular care. The training of nurses in acute cardiovascular care is additionally addressed. Intensive cardiovascular care unit expertise is not limited to within the unit's geographical boundaries, extending to different specialties and subspecialties of cardiology and other specialties in order to optimally manage the wide scope of acute cardiovascular conditions in frequently highly complex patients. This position paper therefore addresses the need for the inclusion of acute cardiac care and intensive cardiovascular care units within a hospital network, linking university medical centres, large community hospitals, and smaller

  15. Techno-economic analysis of fuel cell auxiliary power units as alternative to idling

    Science.gov (United States)

    Jain, Semant; Chen, Hsieh-Yeh; Schwank, Johannes

    This paper presents a techno-economic analysis of fuel-cell-based auxiliary power units (APUs), with emphasis on applications in the trucking industry and the military. The APU system is intended to reduce the need for discretionary idling of diesel engines or gas turbines. The analysis considers the options for on-board fuel processing of diesel and compares the two leading fuel cell contenders for automotive APU applications: proton exchange membrane fuel cell and solid oxide fuel cell. As options for on-board diesel reforming, partial oxidation and auto-thermal reforming are considered. Finally, using estimated and projected efficiency data, fuel consumption patterns, capital investment, and operating costs of fuel-cell APUs, an economic evaluation of diesel-based APUs is presented, with emphasis on break-even periods as a function of fuel cost, investment cost, idling time, and idling efficiency. The analysis shows that within the range of parameters studied, there are many conditions where deployment of an SOFC-based APU is economically viable. Our analysis indicates that at an APU system cost of 100 kW -1, the economic break-even period is within 1 year for almost the entire range of conditions. At 500 kW -1 investment cost, a 2-year break-even period is possible except for the lowest end of the fuel consumption range considered. However, if the APU investment cost is 3000 kW -1, break-even would only be possible at the highest fuel consumption scenarios. For Abram tanks, even at typical land delivered fuel costs, a 2-year break-even period is possible for APU investment costs as high as 1100 kW -1.

  16. Structure and Origins of Trends in Hydrological Measures over the western United States

    Energy Technology Data Exchange (ETDEWEB)

    Das, T; Hidalgo, H G; Dettinger, M D; Cayan, D R; Pierce, D W; Bonfils, C; Barnett, T P; Bala, G; Mirin, A

    2008-08-22

    This study examines, at 1/8 degree spatial resolution, the geographic structure of observed trends in key hydrologically relevant variables across the western United States (U.S.) over the period 1950-1999, and investigates whether these trends are statistically significantly different from trends associated with natural climate variations. A number of variables were analyzed, including late winter and spring temperature, winter-total snowy days as a fraction of winter-total wet days, 1st April Snow Water Equivalent (SWE) as a fraction of October through March precipitation total (P{sub ONDJFM}), and seasonal (January-February-March; JFM) accumulated runoff as a fraction of water year accumulated runoff. The observed changes were compared to natural internal climate variability simulated by an 850-year control run of the CCSM3-FV climate model, statistically downscaled to a 1/8 degree grid using the method of Constructed Analogues. Both observed and downscaled temperature and precipitation data were then used to drive the Variable Infiltration Capacity (VIC) hydrological model to obtain the hydrological variables analyzed in this study. Large trends (magnitudes found less than 5% of the time in the long control run) are common in the observations, and occupy substantial part of the area (37-42%) over the mountainous western U.S. These trends are strongly related to the large scale warming that appears over 89% of the domain. The strongest changes in the hydrologic variables, unlikely to be associated with natural variability alone, have occurred at medium elevations (750 m to 2500 m for JFM runoff fractions and 500 m-3000 m for SWE/PONDJFM) where warming has pushed temperatures from slightly below to slightly above freezing. Further analysis using the data on selected catchments across the simulation domain indicated that hydroclimatic variables must have changed significantly (at 95% confidence level) over at least 45% of the total catchment area to achieve a

  17. Structure and integrity of fish assemblages in streams associated to conservation units in Central Brazil

    Directory of Open Access Journals (Sweden)

    Thiago Belisário d'Araújo Couto

    Full Text Available This study aims to characterize the spatial and seasonal distribution of the fish assemblage and evaluate the integrity of streams in a sustainable use area that includes integral protection conservation units in Distrito Federal, Central Brazil (Cerrado biome. For the study, 12 stretches of 8 streams were sampled in 2008 (dry season and 2009 (wet season. For that evaluation was estimated the Physical Habitat Index (PHI, vegetation cover (VC, pH, dissolved oxygen, turbidity, and conductivity. We recorded 22 species, about eight undescribed species, by a total of 2,327 individuals. The most representative families in number of species were Characidae (31.8%, Loricariidae (31.8%, and Crenuchidae (13.6%. Knodus moenkhausii was the most abundant species with 1,476 individuals, added to Astyanax sp., Phalloceros harpagos, and Hasemania sp. they represent over 95% of the total abundance. The species Astyanax sp. (occurring in 79.2% of the stretches and K. moenkhausii (50.0% were considered constant in both seasons. The longitudinal gradient (River Continuum exerts a strong influence on the studied assemblage. According to CCA, the variables that structure the fish assemblage are based on aspects related to water volume and habitat complexity. No seasonal variation in richness, diversity, abundance, and mass were detected. A cluster analysis suggests a separation of species composition between the stretches of higher and lower orders, which was not observed for seasonality. The streams were considered well preserved (mean PHI 82.9±7.5%, but in some stretches were observed anthropogenic influence, detected in the water quality and, mainly, on the riparian vegetation integrity. The exotic species Poecilia reticulata was sampled in the two stretches considered most affected by anthropogenic activities by PHI, conductivity, and VC.

  18. Population structure of Hispanics in the United States: the multi-ethnic study of atherosclerosis.

    Science.gov (United States)

    Manichaikul, Ani; Palmas, Walter; Rodriguez, Carlos J; Peralta, Carmen A; Divers, Jasmin; Guo, Xiuqing; Chen, Wei-Min; Wong, Quenna; Williams, Kayleen; Kerr, Kathleen F; Taylor, Kent D; Tsai, Michael Y; Goodarzi, Mark O; Sale, Michèle M; Diez-Roux, Ana V; Rich, Stephen S; Rotter, Jerome I; Mychaleckyj, Josyf C

    2012-01-01

    Using ~60,000 SNPs selected for minimal linkage disequilibrium, we perform population structure analysis of 1,374 unrelated Hispanic individuals from the Multi-Ethnic Study of Atherosclerosis (MESA), with self-identification corresponding to Central America (n = 93), Cuba (n = 50), the Dominican Republic (n = 203), Mexico (n = 708), Puerto Rico (n = 192), and South America (n = 111). By projection of principal components (PCs) of ancestry to samples from the HapMap phase III and the Human Genome Diversity Panel (HGDP), we show the first two PCs quantify the Caucasian, African, and Native American origins, while the third and fourth PCs bring out an axis that aligns with known South-to-North geographic location of HGDP Native American samples and further separates MESA Mexican versus Central/South American samples along the same axis. Using k-means clustering computed from the first four PCs, we define four subgroups of the MESA Hispanic cohort that show close agreement with self-identification, labeling the clusters as primarily Dominican/Cuban, Mexican, Central/South American, and Puerto Rican. To demonstrate our recommendations for genetic analysis in the MESA Hispanic cohort, we present pooled and stratified association analysis of triglycerides for selected SNPs in the LPL and TRIB1 gene regions, previously reported in GWAS of triglycerides in Caucasians but as yet unconfirmed in Hispanic populations. We report statistically significant evidence for genetic association in both genes, and we further demonstrate the importance of considering population substructure and genetic heterogeneity in genetic association studies performed in the United States Hispanic population.

  19. Population structure of Hispanics in the United States: the multi-ethnic study of atherosclerosis.

    Directory of Open Access Journals (Sweden)

    Ani Manichaikul

    Full Text Available Using ~60,000 SNPs selected for minimal linkage disequilibrium, we perform population structure analysis of 1,374 unrelated Hispanic individuals from the Multi-Ethnic Study of Atherosclerosis (MESA, with self-identification corresponding to Central America (n = 93, Cuba (n = 50, the Dominican Republic (n = 203, Mexico (n = 708, Puerto Rico (n = 192, and South America (n = 111. By projection of principal components (PCs of ancestry to samples from the HapMap phase III and the Human Genome Diversity Panel (HGDP, we show the first two PCs quantify the Caucasian, African, and Native American origins, while the third and fourth PCs bring out an axis that aligns with known South-to-North geographic location of HGDP Native American samples and further separates MESA Mexican versus Central/South American samples along the same axis. Using k-means clustering computed from the first four PCs, we define four subgroups of the MESA Hispanic cohort that show close agreement with self-identification, labeling the clusters as primarily Dominican/Cuban, Mexican, Central/South American, and Puerto Rican. To demonstrate our recommendations for genetic analysis in the MESA Hispanic cohort, we present pooled and stratified association analysis of triglycerides for selected SNPs in the LPL and TRIB1 gene regions, previously reported in GWAS of triglycerides in Caucasians but as yet unconfirmed in Hispanic populations. We report statistically significant evidence for genetic association in both genes, and we further demonstrate the importance of considering population substructure and genetic heterogeneity in genetic association studies performed in the United States Hispanic population.

  20. Unemployment in Western Europe and the United States: A Problem of Demand, Structure, or Measurement?

    Science.gov (United States)

    Haveman, Robert H.

    1978-01-01

    The main thesis of this paper is that measured unemployment bears a different relationship to real excess labor supply in the 1970s than it did in the 1960s. This thesis is used to explain the increase in measured unemployment in the Netherlands, Sweden, the United Kingdom, and the United States. (Author/EB)

  1. A comparative analysis of business structures suitable for farmer-owned wind power projects in the United States

    Energy Technology Data Exchange (ETDEWEB)

    Bolinger, Mark [Lawrence Berkeley National Laboratory, MS 90-4000, One Cyclotron Road, Berkeley, CA 94720 (United States)]. E-mail: mabolinger@lbl.gov; Wiser, Ryan [Lawrence Berkeley National Laboratory, MS 90-4000, One Cyclotron Road, Berkeley, CA 94720 (United States)

    2006-09-15

    For years, farmers in the United States have looked with envy on their European counterparts' ability to profitably farm the wind through ownership of distributed, utility-scale wind projects. Only within the past few years, however, has farmer- or community-owned wind power development become a reality in the United States. The primary hurdle to this type of development in the United States has been devising and implementing suitable business and legal structures that enable such projects to take advantage of tax-based federal incentives for wind power. This article discusses the limitations of such incentives in supporting farmer- or community-owned wind projects, describes four ownership structures that potentially overcome such limitations, and finally conducts comparative financial analysis on those four structures, using as an example a hypothetical 1.5 MW farmer-owned project located in the state of Oregon. We find that material differences in the competitiveness of each structure do exist, but that choosing the best structure for a given project will largely depend on the conditions at hand; e.g., the ability of the farmer(s) to utilize tax credits, preference for individual versus 'cooperative' ownership, and the state and utility service territory in which the project will be located.

  2. A comparative analysis of business structures suitable forfarmer-owned wind power projects in the United States

    Energy Technology Data Exchange (ETDEWEB)

    Bolinger, Mark; Wiser, Ryan

    2004-11-11

    For years, farmers in the United States have looked with envy on their European counterparts' ability to profitably farm the wind through ownership of distributed, utility-scale wind projects. Only within the past few years, however, has farmer- or community-owned wind power development become a reality in the United States. The primary hurdle to this type of development in the United States has been devising and implementing suitable business and legal structures that enable such projects to take advantage of tax-based federal incentives for wind power. This article discusses the limitations of such incentives in supporting farmer- or community-owned wind projects, describes four ownership structures that potentially overcome such limitations, and finally conducts comparative financial analysis on those four structures, using as an example a hypothetical 1.5 MW farmer-owned project located in the state of Oregon. We find that material differences in the competitiveness of each structure do exist, but that choosing the best structure for a given project will largely depend on the conditions at hand; e.g., the ability of the farmer(s) to utilize tax credits, preference for individual versus ''cooperative'' ownership, and the state and utility service territory in which the project will be located.

  3. Structural and biomechanical basis of mitochondrial movement in eukaryotic cells

    Directory of Open Access Journals (Sweden)

    Wu M

    2013-10-01

    Full Text Available Min Wu,1 Aruna Kalyanasundaram,2 Jie Zhu1 1Laboratory of Biomechanics and Engineering, Institute of Biophysics, College of Science, Northwest A&F University, Yangling, Shaanxi, People's Republic of China; 2College of Pharmacology, University of Illinois at Chicago, Chicago, IL, USA Abstract: Mitochondria serve as energy-producing organelles in eukaryotic cells. In addition to providing the energy supply for cells, the mitochondria are also involved in other processes, such as proliferation, differentiation, information transfer, and apoptosis, and play an important role in regulation of cell growth and the cell cycle. In order to achieve these functions, the mitochondria need to move to the corresponding location. Therefore, mitochondrial movement has a crucial role in normal physiologic activity, and any mitochondrial movement disorder will cause irreparable damage to the organism. For example, recent studies have shown that abnormal movement of the mitochondria is likely to be the reason for Charcot–Marie–Tooth disease, amyotrophic lateral sclerosis, Alzheimer's disease, Huntington's disease, Parkinson's disease, and schizophrenia. So, in the cell, especially in the particular polarized cell, the appropriate distribution of mitochondria is crucial to the function and survival of the cell. Mitochondrial movement is mainly associated with the cytoskeleton and related proteins. However, those components play different roles according to cell type. In this paper, we summarize the structural basis of mitochondrial movement, including microtubules, actin filaments, motor proteins, and adaptin, and review studies of the biomechanical mechanisms of mitochondrial movement in different types of cells. Keywords: mitochondrial movement, microtubules, actin filaments, motor proteins, adaptin

  4. The Cell Probe Complexity of Succinct Data Structures

    DEFF Research Database (Denmark)

    Gal, Anna; Miltersen, Peter Bro

    2003-01-01

    In the cell probe model with word size 1 (the bit probe model), a static data structure problem is given by a map , where is a set of possible data to be stored, is a set of possible queries (for natural problems, we have ) and is the answer to question about data . A solution is given by a repre......In the cell probe model with word size 1 (the bit probe model), a static data structure problem is given by a map , where is a set of possible data to be stored, is a set of possible queries (for natural problems, we have ) and is the answer to question about data . A solution is given...

  5. Relating structure and function of inner hair cell ribbon synapses.

    Science.gov (United States)

    Wichmann, C; Moser, T

    2015-07-01

    In the mammalian cochlea, sound is encoded at synapses between inner hair cells (IHCs) and type I spiral ganglion neurons (SGNs). Each SGN receives input from a single IHC ribbon-type active zone (AZ) and yet SGNs indefatigably spike up to hundreds of Hz to encode acoustic stimuli with submillisecond precision. Accumulating evidence indicates a highly specialized molecular composition and structure of the presynapse, adapted to suit these high functional demands. However, we are only beginning to understand key features such as stimulus-secretion coupling, exocytosis mechanisms, exo-endocytosis coupling, modes of endocytosis and vesicle reformation, as well as replenishment of the readily releasable pool. Relating structure and function has become an important avenue in addressing these points and has been applied to normal and genetically manipulated hair cell synapses. Here, we review some of the exciting new insights gained from recent studies of the molecular anatomy and physiology of IHC ribbon synapses.

  6. Porous matrix structures for alkaline electrolyte fuel cells

    Science.gov (United States)

    Vine, R. W.; Narsavage, S. T.

    1975-01-01

    A number of advancements have been realized by a continuing research program to develop higher chemically stable porous matrix structures with high bubble pressure (crossover resistance) for use as separators in potassium hydroxide electrolyte fuel cells. More uniform, higher-bubble-pressure asbestos matrices were produced by reconstituting Johns-Manville asbestos paper; Fybex potassium titanate which was found compatible with 42% KOH at 250 F for up to 3000 hr; good agreement was found between bubble pressures predicted by an analytical study and those measured with filtered structures; Teflon-bonded Fybex matrices with bubble pressures greater than 30 psi were obtained by filtering a water slurry of the mixture directly onto fuel cell electrodes; and PBI fibers have satisfactory compatibility with 42% KOH at 250 F.

  7. Algorithm and program for precise determination of unit-cell parameters of single crystal taking into account the sample eccentricity

    Science.gov (United States)

    Dudka, A. P.; Smirnova, E. S.; Verin, I. A.; Bolotina, N. B.

    2017-07-01

    A technique has been developed to refine the unit-cell parameters of single crystals with minimization of the influence of instrumental errors on the result. The corresponding computational procedure HuberUB is added to the software package of Huber-5042 diffractometer with a point detector and closedcycle helium cryostat Displex DE-202. The parameters of unit cell, its orientation, the goniometer zero angles, the sample eccentricity, the distances in the goniometer, and the radiation wavelength were refined by the nonlinear least-squares method, which allows imposition of constraints on the unit-cell parameters, depending on the crystal symmetry. The technique is approved on a LuB12 single crystal. The unit-cell parameters are determined in a temperature range of 20-295 K, with an absolute error not larger than 0.0004 Å (the relative error is of 5 × 10-5). The estimates of the unit-cell parameters obtained by the proposed method are evidenced to be unbiased. Some specific features of the behavior of parameters in the ranges of 120-140 and 20-50 K are revealed, which correlate with the anomalies of the physical properties of the crystal.

  8. Immunoglobulin variable region structure and B-cell malignancies.

    Science.gov (United States)

    Kiyoi, H; Naoe, T

    2001-01-01

    The enormous diversity of immunoglobulin (Ig) variable (V) gene sequences encoding the antibody repertoire are formed by the somatic recombination of relatively few genetic elements. In B-lineage malignancies, Ig gene rearrangements have been widely used for determining clonality and cell origin. The recent development of rapid cloning and sequencing techniques has resulted in a substantial accumulation of IgV region sequences at various stages of B-cell development and has revealed stage-specific trends in the use of V, diversity, joining genes, the degree of noncoding nucleotide addition, and the rate of somatic mutations. Furthermore, sequences from B-lineage malignant cells nearly reflect the characteristics of the normal counterpart at each respective stage of development. Alternatively, from the IgV region structure of the malignant cells, it is possible to speculate at which stage of B-cell development the cells were transformed. As the complete nucleotide sequences of the human Ig heavy and Ig light V region loci have now been determined, the study of Ig genetics has entered into the super-information era.

  9. Prognosis of Allogeneic Haematopoietic Stem Cell Recipients Admitted to the Intensive Care Unit

    DEFF Research Database (Denmark)

    Lindgaard, Sidsel Christy; Nielsen, Jonas; Lindmark, Anders

    2016-01-01

    BACKGROUND: Allogeneic haematopoietic stem cell transplantation (HSCT) is a procedure with inherent complications and intensive care may be necessary. We evaluated the short- and long-term outcomes of the HSCT recipients requiring admission to the intensive care unit (ICU). METHODS: We...... ventilation had a statistically significant effect on in-ICU (p = 0.02), 6-month (p = 0.049) and 1-year (p = 0.014) mortality. Renal replacement therapy also had a statistically significant effect on in-hospital (p = 0.038) and 6-month (p = 0.026) mortality. Short ICU admissions, i.e. ... to the ICU was confirmed in our study. Mechanical ventilation, renal replacement therapy and an ICU admission of ≥10 days were each risk factors for mortality in the first year after ICU admission....

  10. Structural investigation of cell wall polysaccharides of Lactobacillus delbrueckii subsp. bulgaricus 17.

    Science.gov (United States)

    Vinogradov, E; Sadovskaya, I; Cornelissen, A; van Sinderen, D

    2015-09-01

    Lactobacilli are valuable strains for commercial (functional) food fermentations. Their cell surface-associated polysaccharides (sPSs) possess important functional properties, such as acting as receptors for bacteriophages (bacterial viruses), influencing autolytic characteristics and providing protection against antimicrobial peptides. The current report provides an elaborate molecular description of several surface carbohydrates of Lactobacillus delbrueckii subsp. bulgaricus strain 17. The cell surface of this strain was shown to contain short chain poly(glycerophosphate) teichoic acids and at least two different sPSs, designated here as sPS1 and sPS2, whose chemical structures were examined by 2D nuclear magnetic resonance spectroscopy and methylation analysis. Neutral branched sPS1, extracted with n-butanol, was shown to be composed of hexasaccharide repeating units (-[α-d-Glcp-(1-3)-]-4-β-l-Rhap2OAc-4-β-d-Glcp-[α-d-Galp-(1-3)]-4-α-Rhap-3-α-d-Galp-), while the major component of the TCA-extracted sPS2 was demonstrated to be a linear d-galactan with the repeating unit structure being (-[Gro-3P-(1-6)-]-3-β-Galf-3-α-Galp-2-β-Galf-6-β-Galf-3-β-Galp-).

  11. CIF2Cell: Generating geometries for electronic structure programs

    Science.gov (United States)

    Björkman, Torbjörn

    2011-05-01

    The CIF2Cell program generates the geometrical setup for a number of electronic structure programs based on the crystallographic information in a Crystallographic Information Framework (CIF) file. The program will retrieve the space group number, Wyckoff positions and crystallographic parameters, make a sensible choice for Bravais lattice vectors (primitive or principal cell) and generate all atomic positions. Supercells can be generated and alloys are handled gracefully. The code currently has output interfaces to the electronic structure programs ABINIT, CASTEP, CPMD, Crystal, Elk, Exciting, EMTO, Fleur, RSPt, Siesta and VASP. Program summaryProgram title: CIF2Cell Catalogue identifier: AEIM_v1_0 Program summary URL:http://cpc.cs.qub.ac.uk/summaries/AEIM_v1_0.html Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland Licensing provisions: GNU GPL version 3 No. of lines in distributed program, including test data, etc.: 12 691 No. of bytes in distributed program, including test data, etc.: 74 933 Distribution format: tar.gz Programming language: Python (versions 2.4-2.7) Computer: Any computer that can run Python (versions 2.4-2.7) Operating system: Any operating system that can run Python (versions 2.4-2.7) Classification: 7.3, 7.8, 8 External routines: PyCIFRW [1] Nature of problem: Generate the geometrical setup of a crystallographic cell for a variety of electronic structure programs from data contained in a CIF file. Solution method: The CIF file is parsed using routines contained in the library PyCIFRW [1], and crystallographic as well as bibliographic information is extracted. The program then generates the principal cell from symmetry information, crystal parameters, space group number and Wyckoff sites. Reduction to a primitive cell is then performed, and the resulting cell is output to suitably named files along with documentation of the information source generated from any bibliographic information contained in the CIF

  12. Electrochemical cell structure and method of making the same

    Science.gov (United States)

    Schick, Louis Andrew; Libby, Cara Suzanne; Bowen, John Henry; Bourgeois, Richard Scott

    2012-09-25

    An electrochemical cell structure is provided which includes an anode, a cathode spaced apart from said anode, an electrolyte in ionic communication with each of said anode and said cathode and a nonconductive frame. The nonconductive frame includes at least two components that support each of said anode, said cathode and said electrolyte and define at least one flowpath for working fluids and for products of electrochemical reaction.

  13. A diesel fuel processor for fuel-cell-based auxiliary power unit applications

    Science.gov (United States)

    Samsun, Remzi Can; Krekel, Daniel; Pasel, Joachim; Prawitz, Matthias; Peters, Ralf; Stolten, Detlef

    2017-07-01

    Producing a hydrogen-rich gas from diesel fuel enables the efficient generation of electricity in a fuel-cell-based auxiliary power unit. In recent years, significant progress has been achieved in diesel reforming. One issue encountered is the stable operation of water-gas shift reactors with real reformates. A new fuel processor is developed using a commercial shift catalyst. The system is operated using optimized start-up and shut-down strategies. Experiments with diesel and kerosene fuels show slight performance drops in the shift reactor during continuous operation for 100 h. CO concentrations much lower than the target value are achieved during system operation in auxiliary power unit mode at partial loads of up to 60%. The regeneration leads to full recovery of the shift activity. Finally, a new operation strategy is developed whereby the gas hourly space velocity of the shift stages is re-designed. This strategy is validated using different diesel and kerosene fuels, showing a maximum CO concentration of 1.5% at the fuel processor outlet under extreme conditions, which can be tolerated by a high-temperature PEFC. The proposed operation strategy solves the issue of strong performance drop in the shift reactor and makes this technology available for reducing emissions in the transportation sector.

  14. The political economy of women’s professional basketball in the United States: A structure-conduct-performance approach

    Directory of Open Access Journals (Sweden)

    Ariel ANTHONY

    2012-11-01

    Full Text Available This study examines the political economy of women’s professional basketball in the United States, including both the American Basketball League (ABL and the Women’s National Basketball Association (WNBA. To do so, we employ the structure-conductperformance paradigm (hereafter SCP from industrial organization. In addition to the importance of television revenues and corporate sponsorships to the success of the leagues, we find evidence of economies of scope, bilateral monopoly issues, and reverse causality in the SCP paradigm as applied to women’s professional basketball in the United States.

  15. Planar cell polarity in the inner ear: how do hair cells acquire their oriented structure?

    Science.gov (United States)

    Lewis, Julian; Davies, Alex

    2002-11-05

    Sensory hair cells in the ear and lateral line have an asymmetrical hair-bundle structure, essential for their function as directional mechanotransducers. We examine four questions: (1) how does the planar asymmetry of the individual hair cell originate? (2) How are the orientations of neighboring hair cells coordinated? (3) How is the orientation of a group of hair cells controlled in relation to the ear as a whole? (4) How does the initial cell asymmetry lead to creation of the asymmetrical hair bundle? Studies of the development of hairs and bristles in Drosophila, combined with genetic data from vertebrates, suggest that the answer to questions (1) and (2) lies in asymmetries that develop at the cell cortex and at cell-cell junctions, generated by products of a set of primary planar cell polarity genes, including the transmembrane receptor Frizzled. A separate and largely independent mechanism controls asymmmetric allocation of cell fate determinants such as Numb at mitosis, in Drosophila and possibly in the ear also. Little is known about long-range signals that might orient hair cells globally in the ear, but progress has been made in identifying a set of genes responsible for read-out of the primary polarity specification. These genes, in flies and vertebrates, provide a link to assembly of the polarized cytoskeleton; myosin VIIA appears to belong in this group. The mechanism creating the staircase pattern of stereocilium lengths is unknown, but could involve regulation of stereocilium growth by Ca(2+) ions entering via transduction channels.

  16. Impacts of Repeat Unit Structure and Copolymer Architecture on Thermal and Solution Properties in Homopolymers, Copolymers, and Copolymer Blends

    Science.gov (United States)

    Marrou, Stephen Raye

    Gradient copolymers are a relatively new type of copolymer architecture in which the distribution of comonomers gradually varies over the length of the copolymer chain, resulting in a number of unusual properties derived from the arrangement of repeat units. For example, nanophase-segregated gradient copolymers exhibit extremely broad glass transition temperatures (Tgs) resulting from the wide range of compositions present in the nanostructure. This dissertation presents a number of studies on how repeat unit structure and copolymer architecture dictate bulk and solution properties, specifically taking inspiration from the gradient copolymer architecture and comparing the response from this compositionally heterogeneous material to other more conventional materials. The glass transition behavior of a range of common homopolymers was studied to determine the effects of subunit structure on Tg breadth, observing a significant increase in T g breadth with increasing side chain length in methacrylate-based homopolymers and random copolymers. Additionally, increasing the composition distribution of copolymers, either by blending individual random copolymers of different overall composition or synthesizing random copolymers to high conversion, resulted in significant increases to Tg breadth. Plasticization of homopolymers and random copolymers with low molecular weight additives also served to increase the Tg breadth; the most dramatic effect was observed in the selective plasticization of a styrene/4-vinylpyridine gradient copolymer with increases in T g breadth to values above 100 °C. In addition, the effects of repeat unit structure and copolymer architecture on other polymer properties besides Tg were also investigated. The intrinsic fluorescence of styrene units in styrene-containing copolymers was studied, noting the impact of repeat unit structure and copolymer architecture on the resulting fluorescence spectra in solution. The impact of repeat unit structure on

  17. Structure of Phage P22 Cell Envelope-Penetrating Needle

    Energy Technology Data Exchange (ETDEWEB)

    Olia, A.S.; Casjens, S.; Cingolani, G.

    2009-06-02

    Bacteriophage P22 infects Salmonella enterica by injecting its genetic material through the cell envelope. During infection, a specialized tail needle, gp26, is injected into the host, likely piercing a hole in the host cell envelope. The 2.1-{angstrom} crystal structure of gp26 reveals a 240-{angstrom} elongated protein fiber formed by two trimeric coiled-coil domains interrupted by a triple {beta}-helix. The N terminus of gp26 plugs the portal protein channel, retaining the genetic material inside the virion. The C-terminal tip of the fiber exposes {beta}-hairpins with hydrophobic tips similar to those seen in class II fusion peptides. The {alpha}-helical core connecting these two functionally polarized tips presents four trimerization octads with consensus sequence IXXLXXXV. The slender conformation of the gp26 fiber minimizes the surface exposed to solvent, which is consistent with the idea that gp26 traverses the cell envelope lipid bilayers.

  18. Improved Computational Model of Grid Cells Based on Column Structure

    Institute of Scientific and Technical Information of China (English)

    Yang Zhou; Dewei Wu; Weilong Li; Jia Du

    2016-01-01

    To simulate the firing pattern of biological grid cells, this paper presents an improved computational model of grid cells based on column structure. In this model, the displacement along different directions is processed by modulus operation, and the obtained remainder is associated with firing rate of grid cell. Compared with the original model, the improved parts include that: the base of modulus operation is changed, and the firing rate in firing field is encoded by Gaussian⁃like function. Simulation validates that the firing pattern generated by the improved computational model is more consistent with biological characteristic than original model. Besides, the firing pattern is badly influenced by the cumulative positioning error, but the computational model can also generate the regularly hexagonal firing pattern when the real⁃time positioning results are modified.

  19. Cell population structure prior to bifurcation predicts efficiency of directed differentiation in human induced pluripotent cells

    Science.gov (United States)

    Bargaje, Rhishikesh; Trachana, Kalliopi; Shelton, Martin N.; McGinnis, Christopher S.; Zhou, Joseph X.; Chadick, Cora; Cook, Savannah; Cavanaugh, Christopher; Huang, Sui; Hood, Leroy

    2017-01-01

    Steering the differentiation of induced pluripotent stem cells (iPSCs) toward specific cell types is crucial for patient-specific disease modeling and drug testing. This effort requires the capacity to predict and control when and how multipotent progenitor cells commit to the desired cell fate. Cell fate commitment represents a critical state transition or “tipping point” at which complex systems undergo a sudden qualitative shift. To characterize such transitions during iPSC to cardiomyocyte differentiation, we analyzed the gene expression patterns of 96 developmental genes at single-cell resolution. We identified a bifurcation event early in the trajectory when a primitive streak-like cell population segregated into the mesodermal and endodermal lineages. Before this branching point, we could detect the signature of an imminent critical transition: increase in cell heterogeneity and coordination of gene expression. Correlation analysis of gene expression profiles at the tipping point indicates transcription factors that drive the state transition toward each alternative cell fate and their relationships with specific phenotypic readouts. The latter helps us to facilitate small molecule screening for differentiation efficiency. To this end, we set up an analysis of cell population structure at the tipping point after systematic variation of the protocol to bias the differentiation toward mesodermal or endodermal cell lineage. We were able to predict the proportion of cardiomyocytes many days before cells manifest the differentiated phenotype. The analysis of cell populations undergoing a critical state transition thus affords a tool to forecast cell fate outcomes and can be used to optimize differentiation protocols to obtain desired cell populations. PMID:28167799

  20. Thickness of the Upper Hell Creek hydrogeologic unit in the Powder River structural basin

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — These data represent the thickness, in feet, of the Upper Hell Creek hydrogeologic unit in the Powder River basin. The data are presented as ASCII text files that...

  1. Altitude of the top of the middle Fort Union hydrogeologic unit in the Williston structural basin

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — These data represent the altitude, in feet above North American Vertical Datum of 1988 (NAVD88), of the middle Fort Union hydrogeologic unit in the Williston...

  2. Altitude of the top of the Upper Hell Creek hydrogeologic unit in the Williston structural basin

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — These data represent the altitude, in feet above North American Vertical Datum of 1988 (NAVD88), of the Upper Hell Creek hydrogeologic unit in the Williston...

  3. Thickness of the middle Fort Union hydrogeologic unit in the Powder River structural basin

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — These data represent the thickness, in feet, of the middle Fort Union hydrogeologic unit in the Powder River basin. The data are presented as ASCII text files that...

  4. Forest structure and aboveground biomass in the southwestern United States from MODIS and MISR

    Science.gov (United States)

    Red band bidirectional reflectance factor data from the NASA MODerate resolution Imaging Spectroradiometer (MODIS) acquired over the southwestern United States were interpreted through a simple geometric–optical (GO) canopy reflectance model to provide maps of fractional crown cover (dimensionless),...

  5. Altitude of the top of the basal confining unit in the Powder River structural basin

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — These data represent the altitude, in feet above North American Vertical Datum of 1988 (NAVD88), of the basal confining unit in the Powder River basin. The data are...

  6. Structural constraints and dynamics of bacterial cell wall architecture

    Directory of Open Access Journals (Sweden)

    Miguel Angel De Pedro

    2015-05-01

    Full Text Available The peptidoglycan wall (PG is a unique structure which confers physical strength and defined shape to bacteria. It consists of a net-like macromolecule of peptide interlinked glycan chains overlying the cell membrane. The structure and layout of the PG dictates that the wall has to be continuously modified as bacteria go through division, morphological differentiation and adaptive responses. The PG is poorly known in structural terms. However, to understand morphogenesis a precise knowledge of glycan strand arrangement and of local effects of the different kinds of subunits is essential. The scarcity of data led to a conception of the PG as a regular, highly ordered structure which strongly influenced growth models. Here, we review the structure of the PG to define a more realistic conceptual framework. We discuss the consequences of the plasticity of murein architecture in morphogenesis and try to define a set of minimal structural constraints that must be fulfilled by any model to be compatible with present day information.

  7. Stratigraphic structure of the B1 Tertiary tectonostratigraphic unit in eastern Slovenia

    OpenAIRE

    Bogomir Jelen; Helena Rifelj

    2002-01-01

    High inconsistency and incoherence in the stratigraphy of the Slovenian upper Paleogene and lower Miocene have remained unsolved in the past 150 years. To solve the problem, we tried to rigorously conduct the authentic Galilei’s scientific method. Steps of logical and empirical verification confirmed the existence of the posited B1 Tertiary tectonostratigraphic unit, and a general chronostratigraphic model of new positional relationships of lithologic units resulted from rather good biochrono...

  8. Fuel cell system including a unit for electrical isolation of a fuel cell stack from a manifold assembly and method therefor

    Science.gov (United States)

    Kelley; Dana A. , Farooque; Mohammad , Davis; Keith

    2007-10-02

    A fuel cell system with improved electrical isolation having a fuel cell stack with a positive potential end and a negative potential, a manifold for use in coupling gases to and from a face of the fuel cell stack, an electrical isolating assembly for electrically isolating the manifold from the stack, and a unit for adjusting an electrical potential of the manifold such as to impede the flow of electrolyte from the stack across the isolating assembly.

  9. An Interactive Exercise To Learn Eukaryotic Cell Structure and Organelle Function.

    Science.gov (United States)

    Klionsky, Daniel J.; Tomashek, John J.

    1999-01-01

    Describes a cooperative, interactive problem-solving exercise for studying eukaryotic cell structure and function. Highlights the dynamic aspects of movement through the cell. Contains 15 references. (WRM)

  10. Bidirectional relationship of mast cells-neurovascular unit communication in neuroinflammation and its involvement in POCD.

    Science.gov (United States)

    Li, Nana; Zhang, Xiang; Dong, Hongquan; Hu, Youli; Qian, Yanning

    2017-03-30

    Postoperative cognitive dysfunction (POCD) has been hypothesized to be mediated by surgery-induced neuroinflammation, which is also a key element in the pathobiology of neurodegenerative diseases, stroke, and neuropsychiatric disorders. There is extensive communication between the immune system and the central nervous system (CNS). Inflammation resulting from activation of the innate immune system cells in the periphery can impact central nervous system behaviors, such as cognitive performance. Mast cells (MCs), as the"first responders" in the CNS, can initiate, amplify, and prolong other immune and nervous responses upon activation. In addition, MCs and their secreted mediators modulate inflammatory processes in multiple CNS pathologies and can thereby either contribute to neurological damage or confer neuroprotection. Neuroinflammation has been considered to be linked to neurovascular dysfunction in several neurological disorders. This review will provide a brief overview of the bidirectional relationship of MCs-neurovascular unit communication in neuroinflammation and its involvement in POCD, providing a new and unique therapeutic target for the adjuvant treatment of POCD.

  11. Two-Dimensional Simulation of Mass Transfer in Unitized Regenerative Fuel Cells under Operation Mode Switching

    Directory of Open Access Journals (Sweden)

    Lulu Wang

    2016-01-01

    Full Text Available A two-dimensional, single-phase, isothermal, multicomponent, transient model is built to investigate the transport phenomena in unitized regenerative fuel cells (URFCs under the condition of switching from the fuel cell (FC mode to the water electrolysis (WE mode. The model is coupled with an electrochemical reaction. The proton exchange membrane (PEM is selected as the solid electrolyte of the URFC. The work is motivated by the need to elucidate the complex mass transfer and electrochemical process under operation mode switching in order to improve the performance of PEM URFC. A set of governing equations, including conservation of mass, momentum, species, and charge, are considered. These equations are solved by the finite element method. The simulation results indicate the distributions of hydrogen, oxygen, water mass fraction, and electrolyte potential response to the transient phenomena via saltation under operation mode switching. The hydrogen mass fraction gradients are smaller than the oxygen mass fraction gradients. The average mass fractions of the reactants (oxygen and hydrogen and product (water exhibit evident differences between each layer in the steady state of the FC mode. By contrast, the average mass fractions of the reactant (water and products (oxygen and hydrogen exhibit only slight differences between each layer in the steady state of the WE mode. Under either the FC mode or the WE mode, the duration of the transient state is only approximately 0.2 s.

  12. Salivary gland acinar cells regenerate functional glandular structures in modified hydrogels

    Science.gov (United States)

    Pradhan, Swati

    Xerostomia, a condition resulting from irradiation of the head and neck, affects over 40,000 cancer patients each year in the United States. Direct radiation damage of the acinar cells that secrete fluid and protein results in salivary gland hypofunction. Present medical management for xerostomia for patients treated for upper respiratory cancer is largely ineffective. Patients who have survived their terminal diagnosis are often left with a diminished quality of life and are unable to enjoy the simple pleasures of eating and drinking. This project aims to ultimately reduce human suffering by developing a functional implantable artificial salivary gland. The goal was to create an extracellular matrix (ECM) modified hyaluronic acid (HA) based hydrogel culture system that allows for the growth and differentiation of salivary acinar cells into functional acini-like structures capable of secreting large amounts of protein and fluid unidirectionally and to ultimately engineer a functional artificial salivary gland that can be implanted into an animal model. A tissue collection protocol was established and salivary gland tissue was obtained from patients undergoing head and neck surgery. The tissue specimen was assessed by histology and immunohistochemistry to establish the phenotype of normal salivary gland cells including the native basement membranes. Hematoxylin and eosin staining confirmed normal glandular tissue structures including intercalated ducts, striated ducts and acini. alpha-Amylase and periodic acid schiff stain, used for structures with a high proportion of carbohydrate macromolecules, preferentially stained acinar cells in the tissue. Intercalated and striated duct structures were identified using cytokeratins 19 and 7 staining. Myoepithelial cells positive for cytokeratin 14 were found wrapped around the serous and mucous acini. Tight junction components including ZO-1 and E-cadherin were present between both ductal and acinar cells. Ductal and acinar

  13. Numerical study of self-adaptive vibration suppression for flexible structure using interior inlay viscous fluid unit method

    Science.gov (United States)

    Zhang, Xiongwen; Li, Jun; Xu, Hui; Li, Guojun

    2006-11-01

    This paper investigates the usage of an interior inlay viscous fluid unit as a new vibration suppression method for flexible structures via numerical simulations. The first and second modes of vibration for a beam have been calculated using the commercial computational fluid dynamic package Fluent6.1, together with the liquid surface distribution and the fluid force. The calculated results show that the inlay fluid unit has suppressive effects on flexible structures. The liquid converges self-adaptively to locations of larger vibrations. The fluid force varies with the beam vibration at a phase difference of more than 180°. Thus the fluid force suppresses the beam vibration at most of the time.

  14. Structure-based, rational design of T cell receptors

    Directory of Open Access Journals (Sweden)

    Vincent eZoete

    2013-09-01

    Full Text Available Adoptive cell transfer using engineered T cells is emerging as a promising treatment for metastatic melanoma. Such an approach allows one to introduce TCR modifications that, while maintaining the specificity for the targeted antigen, can enhance the binding and kinetic parameters for the interaction pMHC. Using the well-characterized 2C TCR/SIYR/H-2K(b structure as a model system, we demonstrated that a binding free energy decomposition based on the MM-GBSA approach provides a detailed and reliable description of the TCR/pMHC interactions at the structural and thermodynamic levels. Starting from this result, we developed a new structure-based approach, to rationally design new TCR sequences, and applied it to the BC1 TCR targeting the HLA-A2 restricted NY-ESO-1157-165 cancer-testis epitope. 54% of the designed sequence replacements exhibited improved pMHC-binding as compared to the native TCR, with up to 150 fold increase in affinity, while preserving specificity. Genetically-engineered CD8+ T cells expressing these modified TCRs showed an improved functional activity compared to those expressing BC1 TCR. We measured maximum levels of activities for TCRs within the upper limit of natural affinity. Beyond the affinity threshold at KD < 1 μM we observed an attenuation in cellular function. We have also developed a homology modeling-based approach, TCRep 3D, to obtain accurate structural models of any TCR-pMHC complexes. We have complemented the approach with a simplified rigid method to predict the TCR orientation over pMHC. These methods potentially extend the use of our TCR engineering method to entire TCR repertoires for which no X-ray structure is available. We have also performed a steered molecular dynamics study of the unbinding of the TCR-pMHC complex to get a better understanding of how TCRs interact with pMHCs. This entire rational TCR design pipeline is now being used to produce rationally optimized TCRs for adoptive cell therapies of

  15. Mathematical analysis and STEM observations of arrangement of structural units in 〈001〉 symmetrical tilt grain boundaries.

    Science.gov (United States)

    Inoue, Kazutoshi; Saito, Mitsuhiro; Chen, Chunlin; Kotani, Motoko; Ikuhara, Yuichi

    2016-12-01

    A collaborative work between mathematics and atom-resolved scanning transmission electron microscopy (STEM) has been conducted. The grain boundary in a bicrystal of a simple rock-salt oxide can show a complicated arrangement of structural units, which can be well predicted by an algorithm utilizing the Farey sequence. The estimated arrangements had a nice agreement with those observed by STEM in atomic-scale up to several tens of nanometers.

  16. A quantative evaluation of the reformulated 1996 path-goal theory of work unit leadership via structural equation modelling

    OpenAIRE

    Howieson, William B

    2008-01-01

    In 1996, Professor Robert J House published a reformulated Path-Goal Theory of Work Unit Leadership, based on his earlier 1971 and 1974 theories. Path-goal leadership attempts to explain the impact that leader behaviour has on subordinate motivation, satisfaction and performance. The aim of this context-specific study is to evaluate this reformulated ‘1996 Theory’ via Structural Equation Modelling with engineers from the Royal Air Force as the primary data source. This th...

  17. Inhibition of Autophagy Enhances Curcumin United light irradiation-induced Oxidative Stress and Tumor Growth Suppression in Human Melanoma Cells

    Science.gov (United States)

    Niu, Tianhui; Tian, Yan; Mei, Zhusong; Guo, Guangjin

    2016-01-01

    Malignant melanoma is the most aggressive form of skin carcinoma, which possesses fast propagating and highly invasive characteristics. Curcumin is a natural phenol compound that has various biological activities, such as anti-proliferative and apoptosis-accelerating impacts on tumor cells. Unfortunately, the therapeutical activities of Cur are severely hindered due to its extremely low bioavailability. In this study, a cooperative therapy of low concentration Cur combined with red united blue light irradiation was performed to inspect the synergistic effects on the apoptosis, proliferation and autophagy in human melanoma A375 cell. The results showed that red united blue light irradiation efficaciously synergized with Cur to trigger oxidative stress-mediated cell death, induce apoptosis and inhibit cell proliferation. Meanwhile, Western blotting revealed that combined disposure induced the formation of autophagosomes. Conversely, inhibition of the autophagy enhanced apoptosis, obstructed cell cycle arrest and induced reversible proliferation arrest to senescence. These findings suggest that Cur combined with red united blue light irradiation could generate photochemo-preventive effects via enhancing apoptosis and triggering autophagy, and pharmacological inhibition of autophagy convert reversible arrested cells to senescence, therefore reducing the possibility that damaged cells might escape programmed death. PMID:27502897

  18. Structure of a bacterial cell surface decaheme electron conduit.

    Science.gov (United States)

    Clarke, Thomas A; Edwards, Marcus J; Gates, Andrew J; Hall, Andrea; White, Gaye F; Bradley, Justin; Reardon, Catherine L; Shi, Liang; Beliaev, Alexander S; Marshall, Matthew J; Wang, Zheming; Watmough, Nicholas J; Fredrickson, James K; Zachara, John M; Butt, Julea N; Richardson, David J

    2011-06-07

    Some bacterial species are able to utilize extracellular mineral forms of iron and manganese as respiratory electron acceptors. In Shewanella oneidensis this involves decaheme cytochromes that are located on the bacterial cell surface at the termini of trans-outer-membrane electron transfer conduits. The cell surface cytochromes can potentially play multiple roles in mediating electron transfer directly to insoluble electron sinks, catalyzing electron exchange with flavin electron shuttles or participating in extracellular intercytochrome electron exchange along "nanowire" appendages. We present a 3.2-Å crystal structure of one of these decaheme cytochromes, MtrF, that allows the spatial organization of the 10 hemes to be visualized for the first time. The hemes are organized across four domains in a unique crossed conformation, in which a staggered 65-Å octaheme chain transects the length of the protein and is bisected by a planar 45-Å tetraheme chain that connects two extended Greek key split β-barrel domains. The structure provides molecular insight into how reduction of insoluble substrate (e.g., minerals), soluble substrates (e.g., flavins), and cytochrome redox partners might be possible in tandem at different termini of a trifurcated electron transport chain on the cell surface.

  19. Colloidal quantum dot solar cells exploiting hierarchical structuring

    KAUST Repository

    Labelle, André J.

    2015-02-11

    Extremely thin-absorber solar cells offer low materials utilization and simplified manufacture but require improved means to enhance photon absorption in the active layer. Here, we report enhanced-absorption colloidal quantum dot (CQD) solar cells that feature transfer-stamped solution-processed pyramid-shaped electrodes employed in a hierarchically structured device. The pyramids increase, by up to a factor of 2, the external quantum efficiency of the device at absorption-limited wavelengths near the absorber band edge. We show that absorption enhancement can be optimized with increased pyramid angle with an appreciable net improvement in power conversion efficiency, that is, with the gain in current associated with improved absorption and extraction overcoming the smaller fractional decrease in open-circuit voltage associated with increased junction area. We show that the hierarchical combination of micron-scale structured electrodes with nanoscale films provides for an optimized enhancement at absorption-limited wavelengths. We fabricate 54.7° pyramid-patterned electrodes, conformally apply the quantum dot films, and report pyramid CQD solar cells that exhibit a 24% improvement in overall short-circuit current density with champion devices providing a power conversion efficiency of 9.2%.

  20. Structural basis of cell wall cleavage by a staphylococcal autolysin.

    Directory of Open Access Journals (Sweden)

    Sebastian Zoll

    2010-03-01

    Full Text Available The major autolysins (Atl of Staphylococcus epidermidis and S. aureus play an important role in cell separation, and their mutants are also attenuated in virulence. Therefore, autolysins represent a promising target for the development of new types of antibiotics. Here, we report the high-resolution structure of the catalytically active amidase domain AmiE (amidase S. epidermidis from the major autolysin of S. epidermidis. This is the first protein structure with an amidase-like fold from a bacterium with a gram-positive cell wall architecture. AmiE adopts a globular fold, with several alpha-helices surrounding a central beta-sheet. Sequence comparison reveals a cluster of conserved amino acids that define a putative binding site with a buried zinc ion. Mutations of key residues in the putative active site result in loss of activity, enabling us to propose a catalytic mechanism. We also identified and synthesized muramyltripeptide, the minimal peptidoglycan fragment that can be used as a substrate by the enzyme. Molecular docking and digestion assays with muramyltripeptide derivatives allow us to identify key determinants of ligand binding. This results in a plausible model of interaction of this ligand not only for AmiE, but also for other PGN-hydrolases that share the same fold. As AmiE active-site mutations also show a severe growth defect, our findings provide an excellent platform for the design of specific inhibitors that target staphylococcal cell separation and can thereby prevent growth of this pathogen.

  1. Synthesis,Crystal Structure and Photophysical properties of a Novel Molecule Containing a Triarylamine and an Oxadiazole Units

    Institute of Scientific and Technical Information of China (English)

    于海涛; 张万轩; 白东仁; 孟继本

    2002-01-01

    2-{3-[2-(4-N,N-Di-p-tolylaminophenyl)ethenyl]phenyl}-5-(4-bromophenyl)-1,3,4-oxadiazole(1) containing triarylamine and 2,5-diaryl-1,3,4-oxadiazole units was prepared by hornerWitting reactions.The structure of the compound was confirmed by 1H NMR,IR ,MS and elemental analyses.The crystal structure of 1 was determined by X-ray diffraction analysis.UV absorpiton spectra and photoluminescent spectra were measured.

  2. A piezoelectric spectro-electrochemical study on the structural interconversion for poly(o-phenylenediamine) between its ladder structure with phenazine units and polyaniline-like chains

    Institute of Scientific and Technical Information of China (English)

    TU Xinman; XIE Qingji; WANG Meiling; ZHANG Youyu; YAO Shouzhuo

    2005-01-01

    The combination of reflectance UV-Vis spec-troelectrochemistry with electrochemical quartz crystalmicrobalance (EQCM) and separate reflectance FTIR char-acterization were used to investigate the structural intercon-version for poly(o-phenylenediamine) (PoPD) between its ladder structure with phenazine units and polyaniline-like linear chains. The poly(o-phenylenediamine) films potentio-statically (0.8 V vs. SCE) grew on Au electrodes from 0.20 mol·L-1 H2SO4(PoPD1)or 0.40mol·L-1 NaOH(PoPD2)aqueous solution containing 0.20 mol·L-1 Na2SO4+0.10mol·L-1o-phenylenediamine. By considering the mass of deposited PoPD2 film obtained from the EQCM data and the charge consumed under the current peak at ca. 0.6 V vs. SCE for oxidation of -NH2 groups in as-prepared PoPD2 during potential cycling in 0.10mol·L-1 aqueous H2SO4,the nolar percentage of the polyaniline-like chains was estimated to be 19% (relative to total phenylenediamine units), being in agreement with the result obtained from a formaldehyde combination experiment through the aminocarbonyl reaction. After 40-cycle potential sweeps between 0.2 and 0.8 V vs. SCE the polyaniline-like chains in PoPD2 could be completely converted via intramolecular cyclization into the ladder structure with phenazine units. However, PoPD1 was found to be perfectly composed of the ladder structure with phenazine units, and after 40-cycle potential sweeps between -0.4 and 0.1 V vs. SCE only 2.5% in molar percentage of PoPD's ladder structure could be converted into polyaniline-like chains, suggesting that the ladder structure with phenazine units is thermodynamically more stable due to its possessing higher conjugation.

  3. Growth Factor Independence-1 (Gfi1) Is Required for Pancreatic Acinar Unit Formation and Centroacinar Cell Differentiation

    DEFF Research Database (Denmark)

    Qu, Xiaoling; Nyeng, Pia; Xiao, Fan

    2015-01-01

    BACKGROUND & AIMS: The genetic specification of the compartmentalized pancreatic acinar/centroacinar unit is poorly understood. Growth factor independence-1 (Gfi1) is a zinc finger transcriptional repressor that regulates hematopoietic stem cell maintenance, pre-T-cell differentiation, formation...... of pancreatic acinar cells as well as the centroacinar cells (CACs) in Gfi1(-/-) mice when compared with wild-type littermates. Pancreatic endocrine differentiation, islet architecture, and function were unaffected. Organ domain patterning and the formation of ductal cells occurred normally during the murine...... of granulocytes, inner ear hair cells, and the development of secretory cell types in the intestine. As GFI1/Gfi1 is expressed in human and rodent pancreas, we characterized the potential function of Gfi1 in mouse pancreatic development. METHODS: Gfi1 knockout mice were analyzed at histological and molecular...

  4. Structure and mechanics of proteins from single molecules to cells

    Science.gov (United States)

    Brown, Andre E.

    2009-07-01

    Physical factors drive evolution and play important roles in motility and attachment as well as in differentiation. As animal cells adhere to survive, they generate force and "feel" various mechanical features of their surroundings and respond to externally applied forces. This mechanosensitivity requires a substrate for cells to adhere to and a mechanism for cells to apply force, followed by a cellular response to the mechanical properties of the substrate. We have taken an outside-in approach to characterize several aspects of cellular mechanosensitivity. First, we used single molecule force spectroscopy to measure how fibrinogen, an extracellular matrix protein that forms the scaffold of blood clots, responds to applied force and found that it rapidly unfolds in 23 nm steps at forces around 100 pN. Second, we used tensile testing to measure the force-extension behavior of fibrin gels and found that they behave almost linearly to strains of over 100%, have extensibilities of 170 +/- 15%, and undergo a large volume decrease that corresponds to a large and negative peak in compressibility at low strain, which indicates a structural transition. Using electron microscopy and X-ray scattering we concluded that these properties are likely due to coiled-coil unfolding, as observed at the single molecule level in fibrinogen. Moving inside cells, we used total internal reflection fluorescence and atomic force microscopy to image self-assembled myosin filaments. These filaments of motor proteins that are responsible for cell and muscle contractility were found to be asymmetric, with an average of 32% more force generating heads on one half than the other. This could imply a force imbalance, so that rather than being simply contractile, myosin filaments may also be motile in cells.

  5. Mammalian cells exposed to ionizing radiation: structural and biochemical aspects

    Energy Technology Data Exchange (ETDEWEB)

    Sabanero, M.; Flores V, L. L. [Universidad de Guanajuato, Departamento de Biologia, DCNE, Noria Alta s/n, 36250 Guanajuato, Gto. (Mexico); Azorin V, J. C.; Vallejo, M. A.; Cordova F, T.; Sosa A, M. [Universidad de Guanajuato, Departamento de Ingenieria Fisica, DCI, Loma del Bosque 103, Col. Lomas del Campestre, 37150 Leon, Guanajuato (Mexico); Castruita D, J. P. [Universidad de Guadalajara, Departamento de Ecologia, CUCBA, Las Agujas, 45100 Zapopan, Jalisco (Mexico); Barbosa S, G., E-mail: myrna.sabanero@gmail.com [Universidad de Guanajuato, Departamento de Ciencias Medicas, DCS, 20 de Enero No. 929, Col. Obregon, 37000 Leon, Guanajuato (Mexico)

    2015-10-15

    Acute or chronic exposure to ionizing radiation is a factor that may be hazardous to health. It has been reported that exposure to low doses of radiation (less than 50 mSv / year) and subsequently exposure to high doses have greater effects in people. However, it is unknown molecular and biochemical level alteration. This study, analyzes the susceptibility of a biological system (HeLa Atcc CCL-2 human cervix cancer cell line) to ionizing radiation (6 and 60 mSv/ 90). Our evaluate multiple variables such as: total protein profile, mitochondrial metabolic activity (XTT assay), cell viability (Trypan blue exclusion assay), cytoskeleton (actin micro filaments), nuclei (D API), genomic DNA. The results indicate, that cells exposed to ionizing radiation structurally show alterations in nuclear phenotype and aneuploidy, further disruption in the tight junctions and consequently on the distribution of actin micro filaments. Similar alterations were observed in cells treated with a genotoxic agent (200μM H{sub 2}O{sub 2}/1 h). In conclusion, this multi-criteria assessment enables precise comparisons of the effects of radiation between any biological systems. However, it is necessary to determine stress markers for integration of the effects of ionizing radiation. (Author)

  6. Runx1 Structure and Function in Blood Cell Development.

    Science.gov (United States)

    Bonifer, Constanze; Levantini, Elena; Kouskoff, Valerie; Lacaud, Georges

    2017-01-01

    RUNX transcription factors belong to a highly conserved class of transcriptional regulators which play various roles in the development of the majority of metazoans. In this review we focus on the founding member of the family, RUNX1, and its role in the transcriptional control of blood cell development in mammals. We summarize data showing that RUNX1 functions both as activator and repressor within a chromatin environment, a feature that requires its interaction with multiple other transcription factors and co-factors. Furthermore, we outline how RUNX1 works together with other factors to reshape the epigenetic landscape and the three-dimensional structure of gene loci within the nucleus. Finally, we review how aberrant forms of RUNX1 deregulate blood cell development and cause hematopoietic malignancies.

  7. Numerical modeling of perovskite solar cells with a planar structure

    Science.gov (United States)

    Malyukov, S. P.; Sayenko, A. V.; Ivanova, A. V.

    2016-10-01

    The paper is devoted to the research and development of high-efficiency solar cells with a planar perovskite n-i-p structure. A numerical model of this solar cell in the drift- diffusion approximation based on Poisson equation and continuity equations provided to determine their photoelectric characteristics and design optimization. The author considers the spectral photogeneration, bulk and surface recombination, transport charge carriers in perovskite and their collection by the electron and hole transport layers. As a result of the simulation, it was obtained efficiency dependence on perovskite absorber material thickness and lifetime (diffusion length) of the charge carriers. It is found that in addition to absorption coefficient optimal perovskite thickness is determined largely by the charge carrier diffusion length, and it has the upper limit in thickness of 500-600 nm.

  8. The Structure of Professional Profiles for Tourism in the United Kingdom.

    Science.gov (United States)

    Cooper, Chris; And Others

    The tourism and leisure industries are among the fastest growing in the United Kingdom, generating jobs and spending and stimulating economic development. The hotel and catering sector is by far the best documented of the tourism industry and is the major employer. It is also an underqualified sector, despite a range of courses from craft to…

  9. The Structure of Professional Profiles for Tourism in the United Kingdom.

    Science.gov (United States)

    Cooper, Chris; And Others

    The tourism and leisure industries are among the fastest growing in the United Kingdom, generating jobs and spending and stimulating economic development. The hotel and catering sector is by far the best documented of the tourism industry and is the major employer. It is also an underqualified sector, despite a range of courses from craft to…

  10. The United Nations University: The Concept, History, Structure, Financing, Objectives, Centres and Programmes. Guest Editorial.

    Science.gov (United States)

    Reddy, J.

    2000-01-01

    The United Nations University (UNU) is an international academic organization which brings together leading international scholars to tackle world problems. This article describes for South African scholars, institutions, governments, and their agencies the importance of the work being undertaken by the UNU and encourages their participation. (EV)

  11. Quadratic maximization on the unit simplex: structure, stability, genericity and application in biology

    NARCIS (Netherlands)

    Still, Georg J.; Ahmed, F.

    The paper deals with the simple but important problem of maximizing a (nonconvex) quadratic function on the unit simplex. This program is directly related to the concept of evolutionarily stable strategies (ESS) in biology. We discuss this relation and study optimality conditions, stability and

  12. A Multifaceted FISH Approach to Study Endogenous RNAs and DNAs within Native Nuclear and Cell Structure

    Science.gov (United States)

    Byron, Meg; Hall, Lisa L.; Lawrence, Jeanne B.

    2013-01-01

    Fluorescence in situ hybridization (FISH) is not a singular technique, but a battery of powerful and versatile tools to examine the distribution of endogenous genes and RNAs in precise context with each other and in relation to specific proteins or cell structures. This unit offers the details of highly sensitive and successful protocols that were initially developed largely in our lab and honed over a number of years. Our emphasis is on analysis of nuclear RNAs and DNA to address specific biological questions about nuclear structure, pre-mRNA metabolism or the role of non-coding RNAs, although cytoplasmic RNA detection is also provided and generally discussed. Multi-faceted molecular cytological approaches bring precise resolution and sensitive multi-color detection to illuminate the organization and functional roles of endogenous genes and their RNAs within the native structure of fixed cells. Solutions to several common technical pitfalls are discussed, as are cautions regarding the judicious use of digital imaging and the rigors of analyzing and interpreting complex molecular cytological results. PMID:23315927

  13. Defects in aluminum foam with superfine open-cell structure

    Institute of Scientific and Technical Information of China (English)

    Wang Fang; Zhang Zhimin; Li Baocheng; Wang Lucai

    2008-01-01

    The infiltration casting process for producing aluminum foam includes three steps: preparing precursor using NaCI particles, infiltrating molten aluminum and cleaning NaCI precursor. Defects occur during the preparation of aluminum foam with superfine open-cell structure, and influence the pore structure and performance of aluminum foam materials. The types of the defect and their forming mechanisms are analyzed in this paper. The defects include point defects and linear metal defects, and are caused by the defects in salt precursor and the insufficient infiltration of molten aluminum into precursor. With the choice of proper precursor preparation method and infiltration process parameters, the complete aluminum foam with superfine pores could be achieved.

  14. Bifurcation structure of a model of bursting pancreatic cells

    DEFF Research Database (Denmark)

    Mosekilde, Erik; Lading, B.; Yanchuk, S.;

    2001-01-01

    One- and two-dimensional bifurcation studies of a prototypic model of bursting oscillations in pancreatic P-cells reveal a squid-formed area of chaotic dynamics in the parameter plane, with period-doubling bifurcations on one side of the arms and saddle-node bifurcations on the other....... The transition from this structure to the so-called period-adding structure is found to involve a subcritical period-doubling bifurcation and the emergence of type-III intermittency. The period-adding transition itself is not smooth but consists of a saddle-node bifurcation in which (n + 1)-spike bursting...... behavior is born, slightly overlapping with a subcritical period-doubling bifurcation in which n-spike bursting behavior loses its stability....

  15. Modeling and Structural Optimization of Solid Oxide Fuel Cells

    DEFF Research Database (Denmark)

    Panagakos, Grigorios

    The research conducted in the context of this PhD, lies on the cross section between multi-scale modeling of flow in porous media, electrochemical diffusion and reaction, in combination with Shape and Structural Optimization techniques. More specifi-cally, we have followed two lines of action...... requirements. On the one hand, it needs to secure the intake of fuel into the cell, fact that would require an as low hydraulic resistance as possible, i.e. ideally an open channel and on the other hand to exhibit an as high as possible electronic conductance, which in the ideal case would mean an area blocked...... completely by a material with high conductivity such as coated stainless steel. The balance between these two competing, oppositely driving forces, indicate that there should be a design that satisfies in the best way both. Similar problems have been successfully dealt by structural-topology optimization...

  16. Solar Cells Based on Low-dimensional Nanocomposite Structures

    Directory of Open Access Journals (Sweden)

    S.L. Khrypko

    2016-12-01

    Full Text Available Converting solar energy into electric energy with using of solar batteries is a major task for developers and research teams. In this article we will look at the development of different generations of solar batteries for to create a nanocomposite structure. Production of solar batteries has gone through some steps, taking into account technological and economic aspects that have been associated with improved of their parameters. Thus the first generations of solar batteries have been based on the single-crystal silicon substrates (с-Si. The use of polycrystalline silicon and multi- crystalline allowed lower costs of modules, but due to the efficiency of solar energy conversion. The solar batteries of the second generation were based on thin-film technology, in which use different materials: silicon films based on amorphous silicon (a-Si, a film based on cadmium telluride (CdTe and film selenide copper-indium-gallium (CuInGaSe2, or CIGS. The use of such technology has allowed increasing the coefficient of performance (COP solar cell with a significant reduction in costs. The solar batteries of third-generation based on nanotechnology, nanocrystals and nano-sized clusters of semiconductors. The creation of such solar cells requires availability of a low-dimensional composite structure. Low-dimensional nanocomposite structures that are constructed on quantum dots and nano-porous materials have new modified optoelectronic properties. They can be used in solar elements, where absorption bands can be optimally adapted to the wavelength of radiation light. These structures could theoretically can lead to increased efficiency of solar energy conversion more than 65%, which can double practically current efficiency of solar batteries.

  17. Structure and cell biology of archaeal virus STIV.

    Science.gov (United States)

    Fu, Chi-yu; Johnson, Johnson E

    2012-04-01

    Recent investigations of archaeal viruses have revealed novel features of their structures and life cycles when compared to eukaryotic and bacterial viruses, yet there are structure-based unifying themes suggesting common ancestral relationships among dsDNA viruses in the three kingdoms of life. Sulfolobus solfataricus and the infecting virus Sulfolobus turreted icosahedral virus (STIV) is one of the well-established model systems to study archaeal virus replication and viral-host interactions. Reliable laboratory conditions to propagate STIV and available genetic tools allowed structural characterization of the virus and viral components that lead to the proposal of common capsid ancestry with PRD1 (bacteriophage), Adenovirus (eukaryotic virus) and PBCV (chlorellavirus). Microarray and proteomics approaches systematically analyzed viral replication and the corresponding host responses. Cellular cryo-electron tomography and thin-section EM studies uncovered the assembly and maturation pathway of STIV and revealed dramatic cellular ultra-structure changes upon infection. The viral-induced pyramid-like protrusions on cell surfaces represent a novel viral release mechanism and previously uncharacterized functions in viral replication.

  18. Progress in human embryonic stem cell research in the United States between 2001 and 2010.

    Directory of Open Access Journals (Sweden)

    Keyvan Vakili

    Full Text Available On August 9th, 2001, the federal government of the United States announced a policy restricting federal funds available for research on human embryonic stem cell (hESCs out of concern for the "vast ethical mine fields" associated with the creation of embryos for research purposes. Until the policy was repealed on March 9th, 2009, no U.S. federal funds were available for research on hESCs extracted after August 9, 2001, and only limited federal funds were available for research on a subset of hESC lines that had previously been extracted. This paper analyzes how the 2001 U.S. federal funding restrictions influenced the quantity and geography of peer-reviewed journal publications on hESC. The primary finding is that the 2001 policy did not have a significant aggregate effect on hESC research in the U.S. After a brief lag in early 2000s, U.S. hESC research maintained pace with other areas of stem cell and genetic research. The policy had several other consequences. First, it was tied to increased hESC research funding within the U.S. at the state level, leading to concentration of related activities in a relatively small number of states. Second, it stimulated increased collaborative research between US-based scientists and those in countries with flexible policies toward hESC research (including Canada, the U.K., Israel, China, Spain, and South Korea. Third, it encouraged independent hESC research in countries without restrictions.

  19. Highly Efficient and Exceptionally Durable CO2 Photoreduction to Methanol over Freestanding Defective Single-Unit-Cell Bismuth Vanadate Layers.

    Science.gov (United States)

    Gao, Shan; Gu, Bingchuan; Jiao, Xingchen; Sun, Yongfu; Zu, Xiaolong; Yang, Fan; Zhu, Wenguang; Wang, Chengming; Feng, Zimou; Ye, Bangjiao; Xie, Yi

    2017-03-08

    Unearthing an ideal model for disclosing the role of defect sites in solar CO2 reduction remains a great challenge. Here, freestanding gram-scale single-unit-cell o-BiVO4 layers are successfully synthesized for the first time. Positron annihilation spectrometry and X-ray fluorescence unveil their distinct vanadium vacancy concentrations. Density functional calculations reveal that the introduction of vanadium vacancies brings a new defect level and higher hole concentration near Fermi level, resulting in increased photoabsorption and superior electronic conductivity. The higher surface photovoltage intensity of single-unit-cell o-BiVO4 layers with rich vanadium vacancies ensures their higher carriers separation efficiency, further confirmed by the increased carriers lifetime from 74.5 to 143.6 ns revealed by time-resolved fluorescence emission decay spectra. As a result, single-unit-cell o-BiVO4 layers with rich vanadium vacancies exhibit a high methanol formation rate up to 398.3 μmol g(-1) h(-1) and an apparent quantum efficiency of 5.96% at 350 nm, much larger than that of single-unit-cell o-BiVO4 layers with poor vanadium vacancies, and also the former's catalytic activity proceeds without deactivation even after 96 h. This highly efficient and spectrally stable CO2 photoconversion performances hold great promise for practical implementation of solar fuel production.

  20. Early evidence for complex social structure in Proboscidea from a late Miocene trackway site in the United Arab Emirates

    Science.gov (United States)

    Bibi, Faysal; Kraatz, Brian; Craig, Nathan; Beech, Mark; Schuster, Mathieu; Hill, Andrew

    2012-01-01

    Many living vertebrates exhibit complex social structures, evidence for the antiquity of which is limited to rare and exceptional fossil finds. Living elephants possess a characteristic social structure that is sex-segregated and multi-tiered, centred around a matriarchal family and solitary or loosely associated groups of adult males. Although the fossil record of Proboscidea is extensive, the origin and evolution of social structure in this clade is virtually unknown. Here, we present imagery and analyses of an extensive late Miocene fossil trackway site from the United Arab Emirates. The site of Mleisa 1 preserves exceptionally long trackways of a herd of at least 13 individuals of varying size transected by that of a single large individual, indicating the presence of both herding and solitary social modes. Trackway stride lengths and resulting body mass estimates indicate that the solitary individual was also the largest and therefore most likely a male. Sexual determination for the herd is equivocal, but the body size profile and number of individuals are commensurate with those of a modern elephant family unit. The Mleisa 1 trackways provide direct evidence for the antiquity of characteristic and complex social structure in Proboscidea. PMID:22357934

  1. Early evidence for complex social structure in Proboscidea from a late Miocene trackway site in the United Arab Emirates.

    Science.gov (United States)

    Bibi, Faysal; Kraatz, Brian; Craig, Nathan; Beech, Mark; Schuster, Mathieu; Hill, Andrew

    2012-08-23

    Many living vertebrates exhibit complex social structures, evidence for the antiquity of which is limited to rare and exceptional fossil finds. Living elephants possess a characteristic social structure that is sex-segregated and multi-tiered, centred around a matriarchal family and solitary or loosely associated groups of adult males. Although the fossil record of Proboscidea is extensive, the origin and evolution of social structure in this clade is virtually unknown. Here, we present imagery and analyses of an extensive late Miocene fossil trackway site from the United Arab Emirates. The site of Mleisa 1 preserves exceptionally long trackways of a herd of at least 13 individuals of varying size transected by that of a single large individual, indicating the presence of both herding and solitary social modes. Trackway stride lengths and resulting body mass estimates indicate that the solitary individual was also the largest and therefore most likely a male. Sexual determination for the herd is equivocal, but the body size profile and number of individuals are commensurate with those of a modern elephant family unit. The Mleisa 1 trackways provide direct evidence for the antiquity of characteristic and complex social structure in Proboscidea.

  2. The reaction of the building structure with window unit to the explosiveimpact on the basis of dynamic equation solution

    Directory of Open Access Journals (Sweden)

    Doronin Fedor Leonidovich

    2014-01-01

    Full Text Available When designing residential buildings, additional measures for increasing the strength at dynamic effects indoors are not foreseen. The walls of the structure fixed in the framework are not designed for shock wave caused by explosion of utility gas. When designing a building, the task of the special dynamic load is often reduced to the calculation of the safe shock pressure, exceeding of which leads to the destruction of the structures. The wall with the window area under dynamic effects is a blast relief panel, which reduces the excess pressure inside the room. The proposed method of calculating a design with a window unit allows determining the dynamic reaction of the wall on explosive pulse. The proposed calculation technique of the constructions at shock loads allows tracing the changes of the inertial forces and displacements at any stage of dynamic response. The reaction to dynamic loads can be also set for non-monolithic structures, consisting of different materials with different conditions of fastening. Elastoplastic reaction of a brick wall with glass units was determined using step-by-step method of linear acceleration. The calculation of stress-strain state of brick walls with window panes determined the strength properties of the structures close to the monolithic version. The proposed technique of numerical solution of dynamic equations is applied only in the analysis of elastic systems, in which the dynamic characteristics remain unchanged throughout the reaction process.

  3. Micro and nanofluidic structures for cell sorting and genomic analysis

    Science.gov (United States)

    Morton, Keith J.

    Microfluidic systems promise rapid analysis of small samples in a compact and inexpensive format. But direct scaling of lab bench protocols on-chip is challenging because laminar flows in typical microfluidic devices are characterized by non-mixing streamlines. Common microfluidic mixers and sorters work by diffusion, limiting application to objects that diffuse slowly such as cells and DNA. Recently Huang et.al. developed a passive microfluidic element to continuously separate bio-particles deterministically. In Deterministic Lateral Displacement (DLD), objects are sorted by size as they transit an asymmetric array of microfabricated posts. This thesis further develops DLD arrays with applications in three broad new areas. First the arrays are used, not simply to sort particles, but to move streams of cells through functional flows for chemical treatment---such as on-chip immunofluorescent labeling of blood cells with washing, and on-chip E.coli cell lysis with simultaneous chromosome extraction. Secondly, modular tiling of the basic DLD element is used to construct complex particle handling modes that include beam steering for jets of cells and beads. Thirdly, nanostructured DLD arrays are built using Nanoimprint Lithography (NIL) and continuous-flow separation of 100 nm and 200 nm size particles is demonstrated. Finally a number of ancillary nanofabrication techniques were developed in support of these overall goals, including methods to interface nanofluidic structures with standard microfluidic components such as inlet channels and reservoirs, precision etching of ultra-high aspect ratio (>50:1) silicon nanostructures, and fabrication of narrow (˜ 35 nm) channels used to stretch genomic length DNA.

  4. "Unitized Structure and Differentiated Staffing in the Elementary School." DSP Progress Report No. 1: Structure and Staffing.

    Science.gov (United States)

    Arends, Richard I.; Essig, Don M.

    This report is the first in a series describing the background, theory, and progress of the Differentiated Staffing Project in the Eugene, Oregon, School District. This particular report reviews the history of the project and outlines the organizational structure that has emerged and developed in the experimental elementary schools. A number of…

  5. Investigation of potential fluctuating intra-unit cell magnetic order in cuprates by μ SR

    Science.gov (United States)

    Pal, A.; Akintola, K.; Potma, M.; Ishikado, M.; Eisaki, H.; Hardy, W. N.; Bonn, D. A.; Liang, R.; Sonier, J. E.

    2016-10-01

    We report low temperature muon spin relaxation (μ SR ) measurements of the high-transition-temperature (Tc) cuprate superconductors Bi2 +xSr2 -xCaCu2O8 +δ and YBa2Cu3O6.57 , aimed at detecting the mysterious intra-unit cell (IUC) magnetic order that has been observed by spin-polarized neutron scattering in the pseudogap phase of four different cuprate families. A lack of confirmation by local magnetic probe methods has raised the possibility that the magnetic order fluctuates slowly enough to appear static on the time scale of neutron scattering, but too fast to affect μ SR or nuclear magnetic resonance signals. The IUC magnetic order has been linked to a theoretical model for the cuprates, which predicts a long-range ordered phase of electron-current loop order that terminates at a quantum crictical point (QCP). Our study suggests that lowering the temperature to T ˜25 mK and moving far below the purported QCP does not cause enough of a slowing down of fluctuations for the IUC magnetic order to become detectable on the time scale of μ SR . Our measurements place narrow limits on the fluctuation rate of this unidentified magnetic order.

  6. Results and analysis of saltstone cores taken from saltstone disposal unit cell 2A

    Energy Technology Data Exchange (ETDEWEB)

    Reigel, M. M. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL); Hill, K. A. [Savannah River Site (SRS), Aiken, SC (United States). Savannah River National Lab. (SRNL)

    2016-03-01

    As part of an ongoing Performance Assessment (PA) Maintenance Plan, Savannah River Remediation (SRR) has developed a sampling and analyses strategy to facilitate the comparison of field-emplaced samples (i.e., saltstone placed and cured in a Saltstone Disposal Unit (SDU)) with samples prepared and cured in the laboratory. The primary objectives of the Sampling and Analyses Plan (SAP) are; (1) to demonstrate a correlation between the measured properties of laboratory-prepared, simulant samples (termed Sample Set 3), and the field-emplaced saltstone samples (termed Sample Set 9), and (2) to validate property values assumed for the Saltstone Disposal Facility (SDF) PA modeling. The analysis and property data for Sample Set 9 (i.e. six core samples extracted from SDU Cell 2A (SDU2A)) are documented in this report, and where applicable, the results are compared to the results for Sample Set 3. Relevant properties to demonstrate the aforementioned objectives include bulk density, porosity, saturated hydraulic conductivity (SHC), and radionuclide leaching behavior.

  7. The modeling of a standalone solid-oxide fuel cell auxiliary power unit

    Science.gov (United States)

    Lu, N.; Li, Q.; Sun, X.; Khaleel, M. A.

    In this research, a Simulink model of a standalone vehicular solid-oxide fuel cell (SOFC) auxiliary power unit (APU) is developed. The SOFC APU model consists of three major components: a controller model; a power electronics system model; and an SOFC plant model, including an SOFC stack module, two heat exchanger modules, and a combustor module. This paper discusses the development of the nonlinear dynamic models for the SOFC stacks, the heat exchangers and the combustors. When coupling with a controller model and a power electronic circuit model, the developed SOFC plant model is able to model the thermal dynamics and the electrochemical dynamics inside the SOFC APU components, as well as the transient responses to the electric loading changes. It has been shown that having such a model for the SOFC APU will help design engineers to adjust design parameters to optimize the performance. The modeling results of the SOFC APU heat-up stage and the output voltage response to a sudden load change are presented in this paper. The fuel flow regulation based on fuel utilization is also briefly discussed.

  8. Fungal spore concentrations in two haematopoietic stem cell transplantation (HSCT) units containing distinct air control systems.

    Science.gov (United States)

    Brun, C P; Miron, D; Silla, L M R; Pasqualotto, A C

    2013-04-01

    Invasive fungal diseases have emerged as important causes of morbidity and mortality in haematological patients. In this study air samples were collected in two haematopoietic stem cell transplantation (HSCT) units, in which distinct air-control systems were in place. In hospital 1 no high-efficiency particulate air (HEPA) filter was available whereas in hospital 2 HSCT rooms were equipped with HEPA filters, with positive air pressure in relation to the corridor. A total of 117 samples from rooms, toilets and corridors were obtained during December 2009 to January 2011, using a six-stage Andersen sampler. In both hospitals, the concentration of potentially pathogenic fungi in the air was reduced in patients' rooms compared to corridors (P < 0·0001). Despite the presence of a HEPA filter in hospital 2, rooms in both hospitals showed similar concentrations of potentially pathogenic fungi (P = 0·714). These findings may be explained by the implementation of additional protective measures in hospital 1, emphasizing the importance of such measures in protected environments.

  9. Giant repeater F-wave in patients with anterior horn cell disorders. Role of motor unit size.

    Science.gov (United States)

    Ibrahim, I K; el-Abd, M A

    1997-01-01

    Conventional F-wave responses as well as single motor unit F-wave responses together with the volitionally recruited motor unit action potentials (MUAP) were studied in hand and feet muscles of 10 healthy subjects and 32 patients with anterior horn cell disorders. The amplitude of the largest F-wave (Fl) was significantly greater in the affected patients compared with healthy subjects. Giant repeater F-wave responses "up to 4 mV" were recorded in muscles having volitionally recruited giant MUAPs. Although, the group mean percentage of motor unit F-wave responses per stimulation in all tested orthodromic MUAPs was significantly decreased in amyotrophic lateral sclerosis patients, the group mean percentage of motor unit F-wave responses per stimulation in all tested orthodromic MUAPs that gave motor unit F-wave response was significantly increased compared with healthy subjects. The responding orthodromic MUAP gave identical motor unit F-wave response, even for complex polyphasic units. Enhanced monosynaptic (H-) reflex, proximal axon reflex (A-wave), and repetitive muscle response as possible explanations for the giant F-wave responses could be discounted. The electrophysiologic behavior of the giant late responses described here fits well with the criteria of F-waves modulated by newly formed distal (and or proximal) axonal branching.

  10. Cell-based composite materials with programmed structures and functions

    Energy Technology Data Exchange (ETDEWEB)

    None

    2016-03-01

    The present invention is directed to the use of silicic acid to transform biological materials, including cellular architecture into inorganic materials to provide biocomposites (nanomaterials) with stabilized structure and function. In the present invention, there has been discovered a means to stabilize the structure and function of biological materials, including cells, biomolecules, peptides, proteins (especially including enzymes), lipids, lipid vesicles, polysaccharides, cytoskeletal filaments, tissue and organs with silicic acid such that these materials may be used as biocomposites. In many instances, these materials retain their original biological activity and may be used in harsh conditions which would otherwise destroy the integrity of the biological material. In certain instances, these biomaterials may be storage stable for long periods of time and reconstituted after storage to return the biological material back to its original form. In addition, by exposing an entire cell to form CSCs, the CSCs may function to provide a unique system to study enzymes or a cascade of enzymes which are otherwise unavailable.

  11. Structural Analysis and Anticoagulant Activities of the Novel Sulfated Fucan Possessing a Regular Well-Defined Repeating Unit from Sea Cucumber

    OpenAIRE

    Mingyi Wu; Li Xu; Longyan Zhao; Chuang Xiao; Na Gao; Lan Luo; Lian Yang; Zi Li; Lingyun Chen; Jinhua Zhao

    2015-01-01

    Sulfated fucans, the complex polysaccharides, exhibit various biological activities. Herein, we purified two fucans from the sea cucumbers Holothuria edulis and Ludwigothurea grisea. Their structures were verified by means of HPGPC, FT-IR, GC–MS and NMR. As a result, a novel structural motif for this type of polymers is reported. The fucans have a unique structure composed of a central core of regular (1→2) and (1→3)-linked tetrasaccharide repeating units. Approximately 50% of the units from...

  12. The dependence of the electrochemical properties of perfluorosulfonic acid membrane/water systems on repeat unit structure

    Science.gov (United States)

    Kim, Young Gyun; Bae, Young Chan

    2009-07-01

    We developed a molecular thermodynamic framework to describe the dependence of the electrochemical properties of a perfluorosulfonic acid (PFSA) membrane/water system on the polymer structure. To better understand the behavior of the polymer membrane/water system, we developed a lattice model based on lattice cluster theory. We performed hypothetical calculations for a variety of repeat unit structures. We also investigated the correlation between the interaction energy and extending or reducing the chain length of the polymer repeat unit using COMPASS force fields. Our results indicate that the ionic conductivity of the nonpolar CF2CF2 group in the main chain varies with the length of the chain. In addition, the ionic conductivity of different CF2CF2 group chain lengths fluctuates according to hydration level. When OCF2CF3CF groups are substituted at 0 and 1, the predictions of the PFSA membrane agreed well with the experimental data from a Dow membrane. To obtain good ionic conductivity at a high vapor equilibrated hydration level, the nonpolar group in the polymer repeat unit and the substituted group chain connecting the nonpolar group length should both be short, and the substituted group chain connected with the sulfonic group should be long.

  13. S1 satellite DNA repetitive units display identical structure and overall variability in all Anatolian brown frog taxa.

    Science.gov (United States)

    Picariello, Orfeo; Feliciello, Isidoro; Chinali, Gianni

    2016-02-01

    S1 satellite DNA from Palearctic brown frogs has a species-specific structure in all European species. We characterized S1 satellite DNA from the Anatolian brown frogs Rana macrocnemis, R. camerani, and R. holtzi in order to define their taxonomic rank and the structure of this satellite in this frog lineage. Southern blots of genomic DNA digested with KpnI, EcoRV, NdeI, NheI, or StuI produced the same pattern of satellite DNA bands. Moreover, quantitative dot blots showed that this satellite DNA accounts for 0.1 % of the genome in all taxa. Analysis of the overall genomic variability of the S1a repeat sequence in specimens from various populations demonstrated that this repetitive unit also has the same size (476 bp), the same most common sequence (MCS) and the same overall variability in all three taxa, and also in R. macrocnemis tavasensis. The S1a repetitive unit presents three deletions of 9, 8 and 1 bp compared to the 494-bp S1a repeat from European frogs. The S1a MCS has three variable positions (sequence WWTK in positions 183-186), due to the presence of two repeat subpopulations with motifs AATG and WWTT in all taxa. Unlike previously analyzed mitochondrial and nuclear sequences that show considerable variations among these taxa, no difference could be detected in the structure and variability of the S1 satellite repetitive units. This suggests that these taxa should belong to a single species. Our results indicate that this satellite DNA variety probably formed when the Anatolian lineage radiated from common ancestor about 4 mya, and since then has maintained its structure in all four taxa examined.

  14. Seismic structural fragility investigation for the San Onofre Nuclear Generating Station, Unit 1 (Project I); SONGS-1 AFWS Project

    Energy Technology Data Exchange (ETDEWEB)

    Wesley, D.A.; Hashimoto, P.S.

    1982-04-01

    An evaluation of the seismic capacities of several of the San Onofre Nuclear Generating Station, Unit 1 (SONGS-1) structures was conducted to determine input to the overall probabilistic methodology developed by Lawrence Livermore National Laboratory. Seismic structural fragilities to be used as input consist of median seismic capacities and their variabilities due to randomness and uncertainty. Potential failure modes were identified for each of the SONGS-1 structures included in this study by establishing the seismic load-paths and comparing expected load distributions to available capacities for the elements of each load-path. Particular attention was given to possible weak links and details. The more likely failure modes were screened for more detailed investigation.

  15. Effect of microwell chip structure on cell microsphere production of various animal cells.

    Science.gov (United States)

    Sakai, Yusuke; Yoshida, Shirou; Yoshiura, Yukiko; Mori, Rhuhei; Tamura, Tomoko; Yahiro, Kanji; Mori, Hideki; Kanemura, Yonehiro; Yamasaki, Mami; Nakazawa, Kohji

    2010-08-01

    The formation of three-dimensional cell microspheres such as spheroids, embryoid bodies, and neurospheres has attracted attention as a useful culture technique. In this study, we investigated a technique for effective cell microsphere production by using specially prepared microchip. The basic chip design was a multimicrowell structure in triangular arrangement within a 100-mm(2) region in the center of a polymethylmethacrylate (PMMA) plate (24x24 mm(2)), the surface of which was modified with polyethylene glycol (PEG) to render it nonadhesive to cells. We also designed six similar chips with microwell diameters of 200, 300, 400, 600, 800, and 1000 microm to investigate the effect of the microwell diameter on the cell microsphere diameter. Rat hepatocytes, HepG2 cells, mouse embryonic stem (ES) cells, and mouse neural progenitor/stem (NPS) cells formed hepatocyte spheroids, HepG2 spheroids, embryoid bodies, and neurospheres, respectively, in the microwells within 5 days of culture. For all the cells, a single microsphere was formed in each microwell under all the chip conditions, and such microsphere configurations remained throughout the culture period. Furthermore, the microsphere diameters of each type of cell were strongly positively correlated with the microwell diameters of the chips, suggesting that microsphere diameter can be factitiously controlled by using different chip conditions. Thus, this chip technique is a promising cellular platform for tissue engineering or regenerative medicine research, pharmacological and toxicological studies, and fundamental studies in cell biology. Copyright 2010 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

  16. The structure of immunocompetent decidual cells in recurrent missed abortions

    Directory of Open Access Journals (Sweden)

    Radović-Janošević Dragana

    2016-01-01

    cells. The completed analysis showed a significantly higher number of CD68 positive macrophages in a decidual tissue of RMA pregnancy (p < 0.01. Conclusion. The number and phenotypic structure of NK cells are significantly different in normal pregnancy decidua and in RMA. The NK cell dominance is present in the RMA group, in favor of CD56+ and CD 57 of subpopulations with increased CD30 of T lymphocyte subpopulations. Macrophages are more numerous in the decidua of pregnancies ended in abortion, so the cause to RMA of unknown etiology in a number of cases could be disregulation of immunocompetent cells.

  17. Synthesis of a new conjugated polymer composed of pyrene and bithiophene units for organic solar cells.

    Science.gov (United States)

    Lee, Sun-Young; Jung, Choong-Hwa; Kang, Jun; Kim, Hee-Joon; Shin, Won Suk; Yoon, Sung Cheol; Moon, Sang-Jin; Lee, Changjin; Hwang, Do-Hoon

    2011-05-01

    An alternating conjugated copolymer composed of pyrene and bithiophene units, poly(DHBT-alt-PYR) has been synthesized. The synthesized polymer was found to exhibit good solution processibility and thermal stability, losing less than 5% of their weight on heating to approximately 370 degrees C. The synthesized polymer showed its maximum absorption and peak PL emission at 401 and 548 nm, respectively. The optical band gap energy of the polymer was determined by absorption onset to be 2.64 eV. Highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) energy levels of the polymer was determined to be -5.48 and -2.84 eV by cyclic voltametry (CV) and the optical band gap. The polymer photovoltaic devices were fabricated with a typical sandwich structure of ITO/PEDOT:PSS/active layer/LiF/Al using poly(DHBT-alt-PYR) as an electron donor and C60-PCBM or C70-PCBM as electron acceptors. The open circuit voltage, short circuit current and fill factor of the device using C70-PCBM as an acceptor were 0.75 V, 3.80 mA/cm2 and 0.28, respectively, and the maximum power conversion efficiency of the device was 0.80%.

  18. Homo- and heterodinuclear coordination polymers based on a tritopic cyclam bis-terpyridine unit: Structure and rheological properties

    Energy Technology Data Exchange (ETDEWEB)

    Qu, Li; Fan, Jiangxia; Ren, Yong; Xiong, Kun [State Key Laboratory Cultivation Base for Nonmetal Composites and Functional Materials, School of Materials Science and Engineering, Southwest University of Science and Technology, Mianyang 621010 (China); Yan, Minhao, E-mail: yanminhao@swust.edu.cn [State Key Laboratory Cultivation Base for Nonmetal Composites and Functional Materials, School of Materials Science and Engineering, Southwest University of Science and Technology, Mianyang 621010 (China); Tuo, Xianguo, E-mail: tuoxg@swust.edu.cn [Laboratory of National Defense for Radioactive Waste and Environmental Security, Southwest University of Science and Technology, Mianyang 621010 (China); Terech, Pierre [SPrAM, UMR CEA/CNRS/UJF-Grenoble 1, INAC, Grenoble F-38054 (France); Royal, Guy [Université Joseph Fourier Grenoble I, Département de Chimie Moléculaire, UMR CNRS-5250, Institut de Chimie Moléculaire de Grenoble, FR CNRS-2607, BP 53, 38041 Grenoble Cedex 9 (France)

    2015-03-01

    An innovative coordination polymer based on a tritopic ligand having the bis-terpyridine cyclam (CHTT) unit is explored. Homo- or heteronuclear 1D coordination polymers can be formed with bivalent metal ions such as Co(II) and Ni(II) in solvent DMF. Creep-recovery curves of the (Co{sup II}){sub 2}CHTT gels formed from 1D coordination polymers were analyzed with the Burgers model and demonstrated an original self-healing property, unusual in the class of molecular gels. The influence of the metal type was studied through the structural features using small-angle neutron scattering (SANS) experiments. In gels, the corresponding network involves genuine fibers (R ≈ 35 Å), bundles of these fibers and also a fraction of finite size aggregates (rods with aspect ratio f ≈ 3–5). We found that the distribution of these latter structural components is sensitive to the metal ions type. Such tritopic 1D coordination polymers exhibit a range of original structural features and a facile control of the developed structures in solutions and gels by tuning their thermodynamic parameters. The versatility associated to the intrinsic dynamic ability of the systems should pave the way to original properties for molecular devices. - Graphical abstract: A tritopic ligand with a bis-terpyridine cyclam (CHTT) unit can form homo- and heterobinuclear coordination polymers with bivalent metal ions in DMF. Gels exhibit a remarkable self-healing property while structures of solutions and gels are studied by small-angle neutron scattering. - Highlights: • Homo- and heteronuclear coordination polymers based on innovative tritopic ligand. • The gels formed from the coordination polymers demonstrated self-healing property. • Influence of the metal type was studied through the structural properties by SANS. • Versatility of the singular system present original properties for molecular device.

  19. The Influence of Structure on the Function of an Administrative Unit: Single Focus Academic Structure or Multiple Focus Academic Structure--Raising Some of the Issues.

    Science.gov (United States)

    Ross, Robert F.; Emmert, Philip

    1990-01-01

    Argues for a multifocused divisional unit versus the traditional single discipline communication department for institutions that are generally small (6 to 10 thousand students) and where enrollments overall have leveled off for both the institution and department. (KEH)

  20. Pleomorphic Structures in Human Blood Are Red Blood Cell-Derived Microparticles, Not Bacteria

    Science.gov (United States)

    Mitchell, Adam J.; Gray, Warren D.; Schroeder, Max; Yi, Hong; Taylor, Jeannette V.; Dillard, Rebecca S.; Ke, Zunlong; Wright, Elizabeth R.; Stephens, David; Roback, John D.; Searles, Charles D.

    2016-01-01

    Background Red blood cell (RBC) transfusions are a common, life-saving therapy for many patients, but they have also been associated with poor clinical outcomes. We identified unusual, pleomorphic structures in human RBC transfusion units by negative-stain electron microscopy that appeared identical to those previously reported to be bacteria in healthy human blood samples. The presence of viable, replicating bacteria in stored blood could explain poor outcomes in transfusion recipients and have major implications for transfusion medicine. Here, we investigated the possibility that these structures were bacteria. Results Flow cytometry, miRNA analysis, protein analysis, and additional electron microscopy studies strongly indicated that the pleomorphic structures in the supernatant of stored RBCs were RBC-derived microparticles (RMPs). Bacterial 16S rDNA PCR amplified from these samples were sequenced and was found to be highly similar to species that are known to commonly contaminate laboratory reagents. Conclusions These studies suggest that pleomorphic structures identified in human blood are RMPs and not bacteria, and they provide an example in which laboratory contaminants may can mislead investigators. PMID:27760197

  1. Picometer registration of zinc impurity states in Bi2Sr2CaCu2O8+δ for phase determination in intra-unit-cell Fourier transform STM

    Science.gov (United States)

    Hamidian, M. H.; Firmo, I. A.; Fujita, K.; Mukhopadhyay, S.; Orenstein, J. W.; Eisaki, H.; Uchida, S.; Lawler, M. J.; Kim, E.-A.; Davis, J. C.

    2012-05-01

    Direct visualization of electronic-structure symmetry within each crystalline unit cell is a new technique for complex electronic matter research (Lawler et al 2010 Nature 466 347-51, Schmidt et al 2011 New J. Phys. 13 065014, Fujita K et al 2012 J. Phys. Soc. Japan 81 011005). By studying the Bragg peaks in Fourier transforms of electronic structure images and particularly by resolving both the real and imaginary components of the Bragg amplitudes, distinct types of intra-unit-cell symmetry breaking can be studied. However, establishing the precise symmetry point of each unit cell in real space is crucial in defining the phase for such a Bragg-peak Fourier analysis. Exemplary of this challenge is the high-temperature superconductor Bi2Sr2CaCu2O8+δ for which the surface Bi atom locations are observable, while it is the invisible Cu atoms that define the relevant CuO2 unit-cell symmetry point. Here we demonstrate, by imaging with picometer precision the electronic impurity states at individual Zn atoms substituted at Cu sites, that the phase established using the Bi lattice produces a ˜2%(2π) error relative to the actual Cu lattice. Such a phase assignment error would not diminish reliability in the determination of intra-unit-cell rotational symmetry breaking at the CuO2 plane (Lawler et al 2010 Nature 466 347-51, Schmidt et al 2011 New J. Phys. 13 065014, Fujita K et al 2012 J. Phys. Soc. Japan 81 011005). Moreover, this type of impurity atom substitution at the relevant symmetry site can be of general utility in phase determination for the Bragg-peak Fourier analysis of intra-unit-cell symmetry.

  2. X-ray powder diffraction characterization of the large-volume unit cell of the M8 murataite polytype

    OpenAIRE

    MAKI, Ryosuke S. S.; Morgan, Peter E. D.; Suzuki, Yoshikazu

    2016-01-01

    We have used conventional X-ray powder diffraction to study one of the largest volume inorganic mixed oxide unit-supercell structures done so far. This necessitated some small-angle X-ray scattering-like observations at low angles from

  3. A micro-structured 5kW complete fuel processor for iso-octane as hydrogen supply system for mobile auxiliary power units Part I. Development of autothermal reforming catalyst and reactor

    OpenAIRE

    Kolb, Gunther; Baier, Tobias; Schürer, Jochen; Tiemann, David; Ziogas, Athanassios; Ehwald, Hermann; Alphonse, Pierre

    2008-01-01

    A micro-structured autothermal reformer was developed for a fuel processing/fuel cell system running on iso-octane and designed for an electrical power output of 5kWel. The target application was an automotive auxiliary power unit (APU). The work covered both catalyst and reactor development. In fixed bed screening, nickel and rhodium were identified as the best candidates for autothermal reforming of gasoline. Under higher feed flow rates applied in microchannel testing, a catalyst formul...

  4. Self Deployable Ultra-Lightweight Modular Unit for Habitat Structural Applications Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Space deployable and rigidizable structures which are ultra-lightweight, and have high rigidity, space durability, and high impact resistance are desirable to...

  5. 3D Printing Complex Unitized Instrument Optical Benches and Metering Structures Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The objective of this project is to determine the engineering techniques required to manufacture complex, thin-shelled instrument structures. These techniques will...

  6. An Innovative Collagen-Based Cell-Printing Method for Obtaining Human Adipose Stem Cell-Laden Structures Consisting of Core-Sheath Structures for Tissue Engineering.

    Science.gov (United States)

    Yeo, MyungGu; Lee, Ji-Seon; Chun, Wook; Kim, Geun Hyung

    2016-04-11

    Three-dimensional (3D) cell printing processes have been used widely in various tissue engineering applications due to the efficient embedding of living cells in appropriately designed micro- or macro-structures. However, there are several issues to overcome, such as the limited choice of bioinks and tailor-made fabricating strategies. Here, we suggest a new, innovative cell-printing process, supplemented with a core-sheath nozzle and an aerosol cross-linking method, to obtain multilayered cell-laden mesh structure and a newly considered collagen-based cell-laden bioink. To obtain a mechanically and biologically enhanced cell-laden structure, we used collagen-bioink in the core region, and also used pure alginate in the sheath region to protect the cells in the collagen during the printing and cross-linking process and support the 3D cell-laden mesh structure. To achieve the most appropriate conditions for fabricating cell-embedded cylindrical core-sheath struts, various processing conditions, including weight fractions of the cross-linking agent and pneumatic pressure in the core region, were tested. The fabricated 3D MG63-laden mesh structure showed significantly higher cell viability (92 ± 3%) compared with that (83 ± 4%) of the control, obtained using a general alginate-based cell-printing process. To expand the feasibility to stem cell-embedded structures, we fabricated a cell-laden mesh structure consisting of core (cell-laden collagen)/sheath (pure alginate) using human adipose stem cells (hASCs). Using the selected processing conditions, we could achieve a stable 3D hASC-laden mesh structure. The fabricated cell-laden 3D core-sheath structure exhibited outstanding cell viability (91%) compared to that (83%) of an alginate-based hASC-laden mesh structure (control), and more efficient hepatogenic differentiations (albumin: ∼ 1.7-fold, TDO-2: ∼ 7.6-fold) were observed versus the control. The selection of collagen-bioink and the new printing strategy

  7. [Transfer of allogeneic stem cell transplant recipients to the intensive care unit: Guidelines from the Francophone society of marrow transplantation and cellular therapy (SFGM-TC)].

    Science.gov (United States)

    Moreau, Anne-Sophie; Bourhis, Jean-Henri; Contentin, Nathalie; Couturier, Marie-Anne; Delage, Jeremy; Dumesnil, Cécile; Gandemer, Virginie; Hichri, Yosr; Jost, Edgar; Platon, Laura; Jourdain, Mercé; Pène, Frédéric; Yakoub-Agha, Ibrahim

    2016-11-01

    Transferring a patient undergoing an allogeneic stem cell transplantation to the intensive care unit (ICU) is always a challenging situation on a medical and psychological point of view for the patient and his relatives as well as for the medical staff. Despite the progress in hematology and intensive care during the last decade, the prognosis of these patients admitted to the ICU remains poor and mortality is around 50 %. The harmonization working party of the SFGM-TC assembled hematologists and intensive care specialist in order to improve conditions and modalities of the transfer of a patient after allogeneic stem cell transplantation to the ICU. We propose a structured medical form comprising all essential information necessary for optimal medical care on ICU. Copyright © 2016. Published by Elsevier Masson SAS.

  8. Flocculation protein structure and cell-cell adhesion mechanism in Saccharomyces cerevisiae.

    Science.gov (United States)

    Goossens, Katty; Willaert, Ronnie

    2010-11-01

    Cell-cell adhesion occurs in a broad spectrum of biological processes, of which yeast flocculation is an area of interest for evolutionary scientists to brewers and winemakers. The flocculation mechanism is based on a lectin-carbohydrate interaction but is not yet fully understood, although the first model dates back to the 1950s. This review will update the current understanding of the complex mechanism behind yeast flocculation. Moreover, modern technologies to measure the forces involved in single carbohydrate-lectin interactions, are discussed. The Flo1 protein has been extensively described as the protein responsible for strong flocculation. Recently, more research has been directed to the detailed analysis of this flocculin. Due to the advances in the field of bioinformatics, more information about Flo1p could be obtained via structurally or functionally related proteins. Here, we review the current knowledge of the Flo1 protein, with a strong emphasis towards its structure.

  9. Xyloglucans from flaxseed kernel cell wall: Structural and conformational characterisation.

    Science.gov (United States)

    Ding, Huihuang H; Cui, Steve W; Goff, H Douglas; Chen, Jie; Guo, Qingbin; Wang, Qi

    2016-10-20

    The structure of ethanol precipitated fraction from 1M KOH extracted flaxseed kernel polysaccharides (KPI-EPF) was studied for better understanding the molecular structures of flaxseed kernel cell wall polysaccharides. Based on methylation/GC-MS, NMR spectroscopy, and MALDI-TOF-MS analysis, the dominate sugar residues of KPI-EPF fraction comprised of (1,4,6)-linked-β-d-glucopyranose (24.1mol%), terminal α-d-xylopyranose (16.2mol%), (1,2)-α-d-linked-xylopyranose (10.7mol%), (1,4)-β-d-linked-glucopyranose (10.7mol%), and terminal β-d-galactopyranose (8.5mol%). KPI-EPF was proposed as xyloglucans: The substitution rate of the backbone is 69.3%; R1 could be T-α-d-Xylp-(1→, or none; R2 could be T-α-d-Xylp-(1→, T-β-d-Galp-(1→2)-α-d-Xylp-(1→, or T-α-l-Araf-(1→2)-α-d-Xylp-(1→; R3 could be T-α-d-Xylp-(1→, T-β-d-Galp-(1→2)-α-d-Xylp-(1→, T-α-l-Fucp-(1→2)-β-d-Galp-(1→2)-α-d-Xylp-(1→, or none. The Mw of KPI-EPF was calculated to be 1506kDa by static light scattering (SLS). The structure-sensitive parameter (ρ) of KPI-EPF was calculated as 1.44, which confirmed the highly branched structure of extracted xyloglucans. This new findings on flaxseed kernel xyloglucans will be helpful for understanding its fermentation properties and potential applications. Crown Copyright © 2016. Published by Elsevier Ltd. All rights reserved.

  10. Impact of road network on the structure of a multifunctional forest landscape unit in southern Turkey.

    Science.gov (United States)

    Eker, Mehmet; Coban, Huseyin Oguz

    2010-01-01

    Forest roads have many kinds of direct and indirect effects such as physical, ecological, and socio-economic effects in landscape scale. In this study the relationship between forest road network and the structure of a multifunctionally planned forest landscape, in the south of Turkey was examined. The aim of the study was to determine whether or not the correlation between road network and landscape structure across a gradient of road density categorical road/no road approach and landscape pattern data from the managed forest landscapes existed. It was concerned with three type polygons that were forest functioning patches, compartments, and stand patches and were associated with higher road density or existing of road network. To quantify the case, it was analyzed whether the spatial structure of forest patches adjacent to roads differs from the spatial structure of forest patches away from roads. GIS was used to integrate quantitative indices of landscape structure. There was little negatively significant relationship between road density and patch area/size, patch perimeter and shape index of patton index (PI) and no correlation with patch number and Fractal Dimension (FD). The forest road network modified spatial pattern of patch shape through PI values. The road network increased the number of patch and decreased mean patch size. The existence of road network was more effective than topography index appearing of PI and FD in the roaded areas. It was indicated to potential reverse impacts of road network on spatial structure of forest compartments in terms of shape index (FD). Highest proportions of harvestable forest areas fall into roaded areas. The results define that road networks are effective on the spatial structure of forest landscape. The forest road network of study area has all probable ecological impacts of forest roads mentioned in context.

  11. Herd management and social variables associated with bulk tank somatic cell count in dairy herds in the eastern United States.

    Science.gov (United States)

    Schewe, R L; Kayitsinga, J; Contreras, G A; Odom, C; Coats, W A; Durst, P; Hovingh, E P; Martinez, R O; Mobley, R; Moore, S; Erskine, R J

    2015-11-01

    The ability to reduce somatic cell counts (SCC) and improve milk quality depends on the effective and consistent application of established mastitis control practices. The US dairy industry continues to rely more on nonfamily labor to perform critical tasks to maintain milk quality. Thus, it is important to understand dairy producer attitudes and beliefs relative to management practices, as well as employee performance, to advance milk quality within the changing structure of the dairy industry. To assess the adoption rate of mastitis control practices in United States dairy herds, as well as assess social variables, including attitudes toward employees relative to mastitis control, a survey was sent to 1,700 dairy farms in Michigan, Pennsylvania, and Florida in January and February of 2013. The survey included questions related to 7 major areas: sociodemographics and farm characteristics, milking proficiency, milking systems, cow environment, infected cow monitoring and treatment, farm labor, and attitudes toward mastitis and related antimicrobial use. The overall response rate was 41% (21% in Florida, 39% in Michigan, and 45% in Pennsylvania). Herd size ranged from 9 to 5,800 cows. Self-reported 3-mo geometric mean bulk tank SCC (BTSCC) for all states was 194,000 cells/mL. Multivariate analysis determined that proven mastitis control practices such as the use of internal teat sealants and blanket dry cow therapy, and not using water during udder preparation before milking, were associated with lower BTSCC. Additionally, farmer and manager beliefs and attitudes, including the perception of mastitis problems and the threshold of concern if BTSCC is above 300,000 cells/mL, were associated with BTSCC. Ensuring strict compliance with milking protocols, giving employees a financial or other penalty if BTSCC increased, and a perceived importance of reducing labor costs were negatively associated with BTSCC in farms with nonfamily employees. These findings highlight the

  12. Structure formation of aerated concrete containing waste coal combustion products generated in the thermal vortex power units

    Science.gov (United States)

    Ivanov, A. I.; Stolboushkin, A. Yu; Temlyanstev, M. V.; Syromyasov, V. A.; Fomina, O. A.

    2016-10-01

    The results of fly ash research, generated in the process of waste coal combustion in the thermal vortex power units and used as an aggregate in aerated concrete, are provided. It is established that fly ash can be used in the production of cement or concrete with low loss on ignition (LOI). The permitted value of LOI in fly ash, affecting the structure formation and operational properties of aerated concrete, are defined. During non-autoclaved hardening of aerated concrete with fly ash aggregate and LOI not higher than 2%, the formation of acicular crystals of ettringite, reinforcing interporous partitions, takes place.

  13. On Methods of Establishing Design Diagrams for Structural Integrity of Slender Complex Types of Breakwater Armour Units

    DEFF Research Database (Denmark)

    Burcharth, Hans F.; Howell, Gary J.

    1988-01-01

    was first presented by NRC (Timco 1981 ). Work based on direct strain-gauge measurement of stresses on large concrete model armour units was presented by Nishigori et al. in 1986.So far, none of the mentioned methods have produced general applicable tools for the design of armour layers. This is mainly...... by other researchers, it might be a frame for a uniform presentation of results. Without a uniformity it will take much longer before the oncoming data on structural integrity can be made useful through contributions to the future data bank which will be needed as a design tool....

  14. Back surface cell structures for reducing recombination in CZ silicon solar cells

    Science.gov (United States)

    King, R. R.; Mitchell, K. W.; Gee, J. M.

    1994-12-01

    Mass-produced terrestrial CZ silicon solar cells are currently entering the domain in which bulk diffusion length is comparable to the cell thickness, so that recombination at the back surface can have a significant effect on device performance. Three manufacturable processes that address the problem of back recombination are examined here: boron diffusion from a deposited doped SiO2, layer; Al-alloyed layers using screen-printed paste; and use of a collecting n* layer on the back interdigitated with the positive electrode. 104 sq cm cells fabricated at Siemens Solar Industries using these back surface structures are characterized by current-voltage, spectral response, photoconductivity decay, and SIMS measurements.

  15. Direct Adaptive Aircraft Control Using Dynamic Cell Structure Neural Networks

    Science.gov (United States)

    Jorgensen, Charles C.

    1997-01-01

    A Dynamic Cell Structure (DCS) Neural Network was developed which learns topology representing networks (TRNS) of F-15 aircraft aerodynamic stability and control derivatives. The network is integrated into a direct adaptive tracking controller. The combination produces a robust adaptive architecture capable of handling multiple accident and off- nominal flight scenarios. This paper describes the DCS network and modifications to the parameter estimation procedure. The work represents one step towards an integrated real-time reconfiguration control architecture for rapid prototyping of new aircraft designs. Performance was evaluated using three off-line benchmarks and on-line nonlinear Virtual Reality simulation. Flight control was evaluated under scenarios including differential stabilator lock, soft sensor failure, control and stability derivative variations, and air turbulence.

  16. Manufacturing of Cast Metal Foams with Irregular Cell Structure

    Directory of Open Access Journals (Sweden)

    Kroupová I.

    2015-06-01

    Full Text Available Metallic foams are materials of which the research is still on-going, with the broad applicability in many different areas (e.g. automotive industry, building industry, medicine, etc.. These metallic materials have specific properties, such as large rigidity at low density, high thermal conductivity, capability to absorb energy, etc. The work is focused on the preparation of these materials using conventional casting technology (infiltration method, which ensures rapid and economically feasible method for production of shaped components. In the experimental part we studied conditions of casting of metallic foams with open pores and irregular cell structure made of ferrous and nonferrous alloys by use of various types of filler material (precursors.

  17. Flight-vehicle structures education in the United States Assessment and recommendations

    Science.gov (United States)

    Noor, Ahmed K.; Dixon, S. C.

    1987-01-01

    An assessment is made of the technical contents of flight-vehicle structures curricula at 41 U.S. universities with accredited aerospace engineering programs. The assessment is based on the technical needs for the new and projected aeronautical and space systems as well as on the likely characteristics of the aerospace engineering work environment. A number of deficiencies and areas of concern are identified and recommendations are presented for enhancing the effectiveness of flight-vehicle structures education. A number of government supported programs that can help aerospace engineering education are listed in the appendix.

  18. In vitro fertilization and stem cell harvesting from human embryos: the law and practice in the United States.

    Science.gov (United States)

    Hook, C Christopher

    2010-07-01

    The challenges before science and medicine are these: science must explore the natural world as thoroughly as possible, while still honoring, protecting, serving and preserving the subject of its investigations, and the human beings for whom it is a tool; medicine must confront disease and disability as effectively as possible, while also honoring, protecting, and preserving those beings for whom it serves - all of those beings, not just some, or even most, at the potential expense of others. These goals are challenged by embryo-destructive human embryonic stem cell research. The human embryo is a human being as clearly defined by embryology, and as such should be protected by the codes governing human subject research. However, because of the "potential" benefits offered by pluripotent stem cells, coupled with abortion politics and a very poorly regulated infertility industry, United States governmental advisory commissions and the scientific, medical, and political communities have attempted to define away the humanity of the human embryo, with a few notable exceptions. Because infertility treatments in the United States are poorly regulated, there are large numbers of supernumerary embryos in cryopreservation. However, only a tiny portion of these will ever be potentially available for research, and thus are not a realistic source of the cells necessary to provide treatments to the millions who might benefit from proposed stem cell based therapies. Cloning will not be the answer either, given the millions of women who must be exploited to provide sufficient numbers of eggs to generate the cloned cell lines. Moreover, the disposition decisions parents must make for their extra embryos are often agonizing, and not uncommonly change. The use of supernumerary embryos as a source for human embryonic stem cells is unethical, will never be a sufficient source for the medical treatments expected from stem cell research, and is often a source of great distress for the

  19. In vitro fertilization and stem cell harvesting from human embryos: the law and practice in the United States

    Directory of Open Access Journals (Sweden)

    C. Christopher Hook

    2010-07-01

    Full Text Available The challenges before science and medicine are these: science must explore the natural world as thoroughly as possible, while still honoring, protecting, serving and preserving the subject of its investigations, and the human beings for whom it is a tool; medicine must confront disease and disability as effectively as possible, while also honoring, protecting, and preserving those beings for whom it serves – all of those beings, not just some, or even most, at the potential expense of others. These goals are challenged by embryo-destructive human embryonic stem cell research. The human embryo is a human being as clearly defined by embryology, and as such should be protected by the codes governing human subject research. However, because of the “potential” benefits offered by pluripotent stem cells, coupled with abortion politics and a very poorly regulated infertility industry, United States governmental advisory commissions and the scientific, medical, and political communities have attempted to define away the humanity of the human embryo, witha few notable exceptions. Because infertility treatments in the United States are poorly regulated, there are large numbersof supernumerary embryos in cryopreservation. However, only a tiny portion of these will ever be potentially available for research, and thus are not a realistic source of the cells necessary to provide treatments to the millions who might benefit from proposed stem cell based therapies. Cloning willnot be the answer either, given the millions of women who must be exploited to provide sufficient numbers of eggs to generate the cloned cell lines. Moreover, the disposition decisions parents must make for their extra embryos are often agonizing, and not uncommonly change.The use of supernumerary embryos as a source for human embryonic stem cells is unethical, will never be a sufficient source for the medical treatments expected from stem cell research, and is often a source of

  20. Frequency and Risk Factors Associated with Cord Graft Failure after Transplant with Single-Unit Umbilical Cord Cells Supplemented by Haploidentical Cells with Reduced-Intensity Conditioning.

    Science.gov (United States)

    Tsai, Stephanie B; Liu, Hongtao; Shore, Tsiporah; Fan, Yun; Bishop, Michael; Cushing, Melissa M; Gergis, Usama; Godley, Lucy; Kline, Justin; Larson, Richard A; Martinez, Guadalupe; Mayer, Sebastian; Odenike, Olatoyosi; Stock, Wendy; Wickrema, Amittha; van Besien, Koen; Artz, Andrew S

    2016-06-01

    Delayed engraftment and cord graft failure (CGF) are serious complications after unrelated cord blood (UCB) hematopoietic stem cell transplantation (HSCT), particularly when using low-cell-dose UCB units. The haplo-cord HSCT approach allows the use of a lower dose single UCB unit by co-infusion of a CD34(+) selected haploidentical graft, which provides early transient engraftment while awaiting durable UCB engraftment. We describe the frequency, complications, and risk factors of CGF after reduced-intensity conditioning haplo-cord HSCT. Among 107 patients who underwent haplo-cord HSCT, 94 were assessable for CGF, defined as risk of CGF. We conclude that assessing chimerism at day 30 may foretell impending CGF, and avoidance of high haploidentical cell doses may reduce risk of CGF after haplo-cord HSCT. However, long-term survival is possible after CGF because of predominant haploidentical or mixed chimerism and hematopoietic function.

  1. The Impact of Structural Break(s on the Validity of Purchasing Power Parity in Turkey: Evidence from Zivot-Andrews and Lagrange Multiplier Unit Root Tests

    Directory of Open Access Journals (Sweden)

    Hakan Kum

    2012-01-01

    Full Text Available This study examines the validity of the purchasing power parity (PPP in Turkey for annual data from 1953 to 2009. While results from both the ADF unit root and the DF-GLS unit root test indicate mixed results, PPP holds for Turkey with the presence of structural breaks which are obtained by Zivot and Andrews and Lagrange Multiplier unit root tests.

  2. Optimized three-unit cubesat structure for Delfi-n3Xt

    NARCIS (Netherlands)

    Go, S.Y.; Bouwmeester, J.; Brouwer, G.F.

    2008-01-01

    For the Delfi-n3Xt mission, follow-up to CubeSat Delfi-C3 [1] of Delft University of Technology, several concepts concerning the Structural Subsystem (STS) have been analysed. One of the main objectives is to reduce the time needed for assembly, integration and testing, and to improve handling capab

  3. Genetic structure of the invasive tree Ailanthus altissima in eastern United States cities

    Science.gov (United States)

    Preston R. Aldrich; Joseph S. Briguglio; Shyam N. Kapadia; Minesh U. Morker; Ankit Rawal; Preeti Kalra; Cynthia D. Huebner; Gary K. Greer

    2010-01-01

    Ailanthus altissima is an invasive tree from Asia. It now occurs in most US states, and although primarily an urban weed, it has become a problem in forested areas especially in the eastern states. Little is known about its genetic structure. We explore its naturalized gene pool from 28 populations, mostly of the eastern US where infestations are...

  4. The Structure-property Relationships of D-π-A BODIPY Dyes for Dye-sensitized Solar Cells.

    Science.gov (United States)

    Mao, Mao; Song, Qin-Hua

    2016-04-01

    BODIPY dyes have attracted considerable attention as potential photosensitizers in dye-sensitized solar cells (DSSCs) owing to their excellent optical properties and facile structural modification. This account focuses on recent advances in the molecular design of D-π-A BODIPY dyes for applications in DSSCs. Special attention has been paid to the structure-property relationships of D-π-A BODIPY dyes for DSSCs. The developmental process in the modified position at the BODIPY core with a donor/acceptor is described. The devices based on 2,6-modified BODIPY dyes exhibit better photovoltaic performance over other modified BODIPY dyes. Meanwhile, the research reveals the correlation of molecular structures (various donor chromophores, extended units, molecular frameworks, and long alkyl groups) with their photophysical and electrochemical properties and relates it to their performance in DSSCs. The structure-property relationships give valuable information and guidelines for designing new D-π-A BODIPY dyes for DSSCs.

  5. Inverted Silicon Nanopencil Array Solar Cells with Enhanced Contact Structures

    Science.gov (United States)

    Liang, Xiaoguang; Shu, Lei; Lin, Hao; Fang, Ming; Zhang, Heng; Dong, Guofa; Yip, Senpo; Xiu, Fei; Ho, Johnny C.

    2016-09-01

    Although three-dimensional nanostructured solar cells have attracted extensive research attention due to their superior broadband and omnidirectional light-harvesting properties, majority of them are still suffered from complicated fabrication processes as well as disappointed photovoltaic performances. Here, we employed our newly-developed, low-cost and simple wet anisotropic etching to fabricate hierarchical silicon nanostructured arrays with different solar cell contact design, followed by systematic investigations of their photovoltaic characteristics. Specifically, nano-arrays with the tapered tips (e.g. inverted nanopencils) are found to enable the more conformal top electrode deposition directly onto the nanostructures for better series and shunt conductance, but its insufficient film coverage at the basal plane would still restrict the charge carrier collection. In contrast, the low-platform contact design facilitates a substantial photovoltaic device performance enhancement of ~24%, as compared to the one of conventional top electrode design, due to the shortened current path and improved lateral conductance for the minimized carrier recombination and series resistance. This enhanced contact structure can not only maintain excellent photon-trapping behaviors of nanostructures, but also help to eliminate adverse impacts of these tapered nano-morphological features on the contact resistance, providing further insight into design consideration in optimizing the contact geometry for high-performance nanostructured photovoltaic devices.

  6. Computing the Density Matrix in Electronic Structure Theory on Graphics Processing Units.

    Science.gov (United States)

    Cawkwell, M J; Sanville, E J; Mniszewski, S M; Niklasson, Anders M N

    2012-11-13

    The self-consistent solution of a Schrödinger-like equation for the density matrix is a critical and computationally demanding step in quantum-based models of interatomic bonding. This step was tackled historically via the diagonalization of the Hamiltonian. We have investigated the performance and accuracy of the second-order spectral projection (SP2) algorithm for the computation of the density matrix via a recursive expansion of the Fermi operator in a series of generalized matrix-matrix multiplications. We demonstrate that owing to its simplicity, the SP2 algorithm [Niklasson, A. M. N. Phys. Rev. B2002, 66, 155115] is exceptionally well suited to implementation on graphics processing units (GPUs). The performance in double and single precision arithmetic of a hybrid GPU/central processing unit (CPU) and full GPU implementation of the SP2 algorithm exceed those of a CPU-only implementation of the SP2 algorithm and traditional matrix diagonalization when the dimensions of the matrices exceed about 2000 × 2000. Padding schemes for arrays allocated in the GPU memory that optimize the performance of the CUBLAS implementations of the level 3 BLAS DGEMM and SGEMM subroutines for generalized matrix-matrix multiplications are described in detail. The analysis of the relative performance of the hybrid CPU/GPU and full GPU implementations indicate that the transfer of arrays between the GPU and CPU constitutes only a small fraction of the total computation time. The errors measured in the self-consistent density matrices computed using the SP2 algorithm are generally smaller than those measured in matrices computed via diagonalization. Furthermore, the errors in the density matrices computed using the SP2 algorithm do not exhibit any dependence of system size, whereas the errors increase linearly with the number of orbitals when diagonalization is employed.

  7. The organizational structure of an intensive care unit influences treatment of hypotension among critically ill patients: A retrospective cohort study.

    Science.gov (United States)

    Boone, M Dustin; Massa, Jennifer; Mueller, Ariel; Jinadasa, Sayuri P; Lee, Joon; Kothari, Rishi; Scott, Daniel J; Callahan, Julie; Celi, Leo Anthony; Hacker, Michele R

    2016-06-01

    Prior studies report that weekend admission to an intensive care unit is associated with increased mortality, potentially attributed to the organizational structure of the unit. This study aims to determine whether treatment of hypotension, a risk factor for mortality, differs according to level of staffing. Using the Multiparameter Intelligent Monitoring in Intensive Care database, we conducted a retrospective study of patients admitted to an intensive care unit at Beth Israel Deaconess Medical Center who experienced one or more episodes of hypotension. Episodes were categorized according to the staffing level, defined as high during weekday daytime (7 am-7 pm) and low during weekends or nighttime (7 pm-7 am). Patients with a hypotensive event on a weekend were less likely to be treated compared with those that occurred during the weekday daytime (P = .02). No association between weekday daytime vs weekday nighttime staffing levels and treatment of hypotension was found (risk ratio, 1.02; 95% confidence interval, 0.98-1.07). Patients with a hypotensive event on a weekend were less likely to be treated than patients with an event during high-staffing periods. No association between weekday nighttime staffing and hypotension treatment was observed. We conclude that treatment of a hypotensive episode relies on more than solely staffing levels. Copyright © 2016 Elsevier Inc. All rights reserved.

  8. A structural econometric model of family valuation and choice of employer-sponsored health insurance in the United States.

    Science.gov (United States)

    Vanness, David J

    2003-09-01

    This paper estimates a fully structural unitary household model of employment and health insurance decisions for dual wage-earner families with children in the United States, using data from the 1987 National Medical Expenditure Survey. Families choose hours of work and the breakdown of compensation between cash wages and health insurance benefits for each wage earner in order to maximize expected utility under uncertain need for medical care. Heterogeneous demand for the employer-sponsored health insurance is thus generated directly from variations in health status and earning potential. The paper concludes by discussing the benefits of using structural models for simulating welfare effects of insurance reform relative to the costly assumptions that must be imposed for identification.

  9. Tetrameric structure of centromeric nucleosomes in interphase Drosophila cells.

    Directory of Open Access Journals (Sweden)

    Yamini Dalal

    2007-08-01

    Full Text Available Centromeres, the specialized chromatin structures that are responsible for equal segregation of chromosomes at mitosis, are epigenetically maintained by a centromere-specific histone H3 variant (CenH3. However, the mechanistic basis for centromere maintenance is unknown. We investigated biochemical properties of CenH3 nucleosomes from Drosophila melanogaster cells. Cross-linking of CenH3 nucleosomes identifies heterotypic tetramers containing one copy of CenH3, H2A, H2B, and H4 each. Interphase CenH3 particles display a stable association of approximately 120 DNA base pairs. Purified centromeric nucleosomal arrays have typical "beads-on-a-string" appearance by electron microscopy but appear to resist condensation under physiological conditions. Atomic force microscopy reveals that native CenH3-containing nucleosomes are only half as high as canonical octameric nucleosomes are, confirming that the tetrameric structure detected by cross-linking comprises the entire interphase nucleosome particle. This demonstration of stable half-nucleosomes in vivo provides a possible basis for the instability of centromeric nucleosomes that are deposited in euchromatic regions, which might help maintain centromere identity.

  10. Microbes produce nanobacteria-like structures, avoiding cell entombment

    Science.gov (United States)

    Bontognali, Tomaso R. R.; Vasconcelos, Crisógono; Warthmann, Rolf J.; Dupraz, Christophe; Bernasconi, Stefano M.; McKenzie, Judith A.

    2008-08-01

    Microsedimentary structures referred to as nanobacteria-likeparticles were described from modern carbonate environments,where they form in close spatial association with sulfate-reducingbacteria (SRB). However, the exact mechanism of their formation,as well as their paleontological significance, remains controversial.Here we report on an investigation of microbe-mineral interactionsin experimentally produced carbonate globules. The experimentswere carried out under anoxic conditions at 30 °C with Desulfovibriobrasiliensis, a SRB known to mediate dolomite formation. Weobserved that extracellular polymeric substances (EPS) secretedby the microbial community play a key role in the mineralizationprocess. Nanobacteria-like particles represent the early stageof carbonate nucleation within the EPS, which progressivelyevolve to larger globules displaying a grainy texture. We excludedthe possibilities that these structures are fossils of nanobacteria,dissolution surfaces, or artifacts created during sample preparation.D. brasiliensis cells are predominantly located outside of theEPS aggregates where mineral growth takes place. As a result,they remain mobile and are rarely entombed within the mineral.This self-preservation behavior may not be limited to D. brasiliensis.Other microbes may produce, or may have produced during thegeological past, biogenic minerals through a similar process.Mineralization within EPS explains why microbial relics arenot necessarily present in biogenic carbonates.

  11. THE FEATURES OF CONNEXINS EXPRESSION IN THE CELLS OF NEUROVASCLAR UNIT IN NORMAL CONDITIONS AND HYPOXIA IN VITRO

    Directory of Open Access Journals (Sweden)

    A. V. Morgun

    2014-01-01

    Full Text Available The aim of this research was to assess a role of connexin 43 (Cx43 and associated molecule CD38 in the regulation of cell-cell interactions in the neurovascular unit (NVU in vitro in physiological conditions and in hypoxia.Materials and methods. The study was done using the original neurovascular unit model in vitro. The NVU consisted of three cell types: neurons, astrocytes, and cerebral endothelial cells derived from rats. Hypoxia was induced by incubating cells with sodium iodoacetate for 30 min at37 °C in standard culture conditions.Results. We investigated the role of connexin 43 in the regulation of cell interactions within the NVU in normal and hypoxic injury in vitro. We found that astrocytes were characterized by high levels of expression of Cx43 and low level of CD38 expression, neurons demonstrated high levels of CD38 and low levels of Cx43. In hypoxic conditions, the expression of Cx43 and CD38 in astrocytes markedly increased while CD38 expression in neurons decreased, however no changes were found in endothelial cells. Suppression of Cx43 activity resulted in down-regulation of CD38 in NVU cells, both in physiological conditions and at chemical hypoxia.Conclusion. Thus, the Cx-regulated intercellular NAD+-dependent communication and secretory phenotype of astroglial cells that are the part of the blood-brain barrier is markedly changed in hypoxia.

  12. Tool for Generation of MAC/GMC Representative Unit Cell for CMC/PMC Analysis

    Science.gov (United States)

    Murthy, Pappu L. N.; Pineda, Evan J.

    2016-01-01

    This document describes a recently developed analysis tool that enhances the resident capabilities of the Micromechanics Analysis Code with the Generalized Method of Cells (MAC/GMC) 4.0. This tool is especially useful in analyzing ceramic matrix composites (CMCs), where higher fidelity with improved accuracy of local response is needed. The tool, however, can be used for analyzing polymer matrix composites (PMCs) as well. MAC/GMC 4.0 is a composite material and laminate analysis software developed at NASA Glenn Research Center. The software package has been built around the concept of the generalized method of cells (GMC). The computer code is developed with a user friendly framework, along with a library of local inelastic, damage, and failure models. Further, application of simulated thermomechanical loading, generation of output results, and selection of architectures to represent the composite material have been automated to increase the user friendliness, as well as to make it more robust in terms of input preparation and code execution. Finally, classical lamination theory has been implemented within the software, wherein GMC is used to model the composite material response of each ply. Thus, the full range of GMC composite material capabilities is available for analysis of arbitrary laminate configurations as well. The primary focus of the current effort is to provide a graphical user interface (GUI) capability that generates a number of different user-defined repeating unit cells (RUCs). In addition, the code has provisions for generation of a MAC/GMC-compatible input text file that can be merged with any MAC/GMC input file tailored to analyze composite materials. Although the primary intention was to address the three different constituents and phases that are usually present in CMCs-namely, fibers, matrix, and interphase-it can be easily modified to address two-phase polymer matrix composite (PMC) materials where an interphase is absent. Currently, the

  13. Structures of xyloglucans in primary cell walls of gymnosperms, monilophytes (ferns sensu lato) and lycophytes.

    Science.gov (United States)

    Hsieh, Yves S Y; Harris, Philip J

    2012-07-01

    Little is known about the structures of the xyloglucans in the primary cell walls of vascular plants (tracheophytes) other than angiosperms. Xyloglucan structures were examined in 13 species of gymnosperms, 13 species of monilophytes (ferns sensu lato), and two species of lycophytes. Wall preparations were obtained, extracted with 6 M sodium hydroxide, and the extracts treated with a xyloglucan-specific endo-(1→4)-β-glucanase preparation. The oligosaccharides released were analysed by matrix-assisted laser-desorption ionisation time-of-flight mass spectrometry and by high-performance anion-exchange chromatography. The xyloglucan oligosaccharide profiles from the gymnosperm walls were similar to those from the walls of most eudicotyledons and non-commelinid monocotyledons, indicating that the xyloglucans were fucogalactoxyloglucans, containing the fucosylated units XXFG and XLFG. The xyloglucan oligosaccharide profiles for six of the monilophyte species were similar to those of the gymnosperms, indicating they were also fucogalactoxyloglucans. Phylogenetically, these monilophyte species were from both basal and more derived orders. However, the profiles for the other monilophyte species showed various significant differences, including additional oligosaccharides. In three of the species, these additional oligosaccharides contained arabinosyl residues which were most abundant in the profile of Equisetum hyemale. The two species of lycophytes examined, Selaginella kraussiana and Lycopodium cernuum, had quite different xyloglucan oligosaccharide profiles, but neither were fucogalactoxyloglucans. The S. kraussiana profile had abundant oligosaccharides containing arabinosyl residues. The L. cernuum profile indicated the xyloglucan had a very complex structure.

  14. Heparan sulfate proteoglycans: structure, protein interactions and cell signaling

    Directory of Open Access Journals (Sweden)

    Juliana L. Dreyfuss

    2009-09-01

    Full Text Available Heparan sulfate proteoglycans are ubiquitously found at the cell surface and extracellular matrix in all the animal species. This review will focus on the structural characteristics of the heparan sulfate proteoglycans related to protein interactions leading to cell signaling. The heparan sulfate chains due to their vast structural diversity are able to bind and interact with a wide variety of proteins, such as growth factors, chemokines, morphogens, extracellular matrix components, enzymes, among others. There is a specificity directing the interactions of heparan sulfates and target proteins, regarding both the fine structure of the polysaccharide chain as well precise protein motifs. Heparan sulfates play a role in cellular signaling either as receptor or co-receptor for different ligands, and the activation of downstream pathways is related to phosphorylation of different cytosolic proteins either directly or involving cytoskeleton interactions leading to gene regulation. The role of the heparan sulfate proteoglycans in cellular signaling and endocytic uptake pathways is also discussed.Proteoglicanos de heparam sulfato são encontrados tanto superfície celular quanto na matriz extracelular em todas as espécies animais. Esta revisão tem enfoque nas características estruturais dos proteoglicanos de heparam sulfato e nas interações destes proteoglicanos com proteínas que levam à sinalização celular. As cadeias de heparam sulfato, devido a sua variedade estrutural, são capazes de se ligar e interagir com ampla gama de proteínas, como fatores de crescimento, quimiocinas, morfógenos, componentes da matriz extracelular, enzimas, entreoutros. Existe uma especificidade estrutural que direciona as interações dos heparam sulfatos e proteínas alvo. Esta especificidade está relacionada com a estrutura da cadeia do polissacarídeo e os motivos conservados da cadeia polipeptídica das proteínas envolvidas nesta interação. Os heparam

  15. Indium phosphide solar cell research in the United States: Comparison with non-photovoltaic sources

    Science.gov (United States)

    Weinberg, I.; Swartz, C. K.; Hart, R. E., Jr.

    1989-01-01

    Highlights of the InP solar cell research program are presented. Homojunction cells with efficiencies approaching 19 percent are demonstrated, while 17 percent is achieved for ITO/InP cells. The superior radiation resistance of the two latter cell configurations over both Si and GaAs cells has been shown. InP cells aboard the LIPS3 satellite show no degradation after more than a year in orbit. Computed array specific powers are used to compare the performance of an InP solar cell array to solar dynamic and nuclear systems.

  16. Synthesis, structure and ring-opening polymerization of macrocyclic arylates containing phthalic unit

    Institute of Scientific and Technical Information of China (English)

    姜洪焱; 陈天禄; 邢彦; 林永华; 徐纪平

    1997-01-01

    A series of maerocyclic arylate diraers have been selectively synthesized by an interfacial polyconden-sation of o-phthaloyldichloride with bisphenols A combination of GPC,FAB-MS,1H and 13C NMR unambiguously confirmed the cyclic nature Although single-crystal X-ray analysis of two such macrocycles reveals no severe strain on the cyclic structures,these macrocycles can undergo facile melt polymerization to give high molecular weight polyary-lates.

  17. Effect of intensive care unit organizational model and structure on outcomes in patients with acute lung injury.

    Science.gov (United States)

    Treggiari, Miriam M; Martin, Diane P; Yanez, N David; Caldwell, Ellen; Hudson, Leonard D; Rubenfeld, Gordon D

    2007-10-01

    Prior studies supported an association between intensive care unit (ICU) organizational model or staffing patterns and outcome in critically ill patients. To examine the association of closed versus open models with patient mortality across adult ICUs in King County (WA). Cohort study of patients with acute lung injury (ALI). ICU structure, organization, and patient care practices were assessed using self-administered mail questionnaires completed by the medical director and nurse manager. We defined closed ICUs as units that required patient transfer to or mandatory patient comanagement by an intensivist and open ICUs as those relying on other organizational models. Outcomes were obtained from the King County Lung Injury Project, a population-based cohort of patients with ALI. The main endpoint was hospital mortality. Of 24 eligible ICUs, 13 ICUs were designated closed and 11 open. Complete survey data were available for 23 (96%) ICUs. Higher physician and nurse availability was reported in closed versus open ICUs. A total of 684 of 1,075 (63%) of patients with ALI were cared for in closed ICUs. After adjusting for potential confounders, patients with ALI cared for in closed ICUs had reduced hospital mortality (adjusted odds ratio, 0.68; 95% confidence interval, 0.53, 0.89; P = 0.004). Consultation by a pulmonologist in open ICUs was not associated with improved mortality (adjusted odds ratio, 0.94; 95% confidence interval, 0.74, 1.20; P = 0.62). These findings were robust for varying assumptions about the study population definition. Patients with ALI cared for in a closed-model ICU have reduced mortality. These data support recommendations to implement structured intensive care in the United States.

  18. Uniting Superhydrophobic, Superoleophobic and Lubricant Infused Slippery Behavior on Copper Oxide Nano-structured Substrates

    Science.gov (United States)

    Ujjain, Sanjeev Kumar; Roy, Pritam Kumar; Kumar, Sumana; Singha, Subhash; Khare, Krishnacharya

    2016-01-01

    Alloys, specifically steel, are considered as the workhorse of our society and are inimitable engineering materials in the field of infrastructure, industry and possesses significant applications in our daily life. However, creating a robust synthetic metallic surface that repels various liquids has remained extremely challenging. The wettability of a solid surface is known to be governed by its geometric nano-/micro structure and the chemical composition. Here, we are demonstrating a facile and economical way to generate copper oxide micro-nano structures with spherical (0D), needle (1D) and hierarchical cauliflower (3D) morphologies on galvanized steel substrates using a simple chemical bath deposition method. These nano/micro textured steel surfaces, on subsequent coating of a low surface energy material display excellent superhydrophobic, superoleophobic and slippery behavior. Polydimethylsiloxane coated textured surfaces illustrate superhydrophobicity with water contact angle about 160°(2) and critical sliding angle ~2°. When functionalized with low-surface energy perfluoroalkylsilane, these surfaces display high repellency for low surface tension oils as well as hydrocarbons. Among them, the hierarchical cauliflower morphology exhibits re-entrant structure thereby showing the best superoleophobicity with contact angle 149° for dodecane. Once infused with a lubricant like silicone oil, they show excellent slippery behavior with low contact angle hysteresis (~ 2°) for water drops. PMID:27752098

  19. Experimental testing of various heat transfer structures in a flat plate thermal energy storage unit

    Science.gov (United States)

    Johnson, Maike; Fiß, Michael; Klemm, Torsten

    2016-05-01

    For solar process heat applications with steam as the working fluid and varying application parameters, a novel latent heat storage concept has been developed using an adaptation of a flat plate heat exchanger as the storage concept. Since the pressure level in these applications usually does not exceed 30 bar, an adaptation with storage material chambers arranged between heat transfer medium chambers is possible. Phase change materials are used as the storage medium, so that the isothermal evaporation of steam during discharging of the storage is paired with the isothermal solidification of the storage material. Heat transfer structures can be inserted into the chambers to adjust the power level for a given application. By combining the required number of flat plate heat exchanger compartments and inserting the appropriate heat transfer structure, the design can easily be adjusted for the required power level and capacity for a specific application. Within this work, the technical feasibility of this concept is proven. The dependence of the operating characteristics on the geometry of the heat exchanger is identified. A focus is on varying the power density by integrating conductive heat structures in the PCM.

  20. Population structure and linkage disequilibrium in elite barley breeding germplasm from the United States

    Institute of Scientific and Technical Information of China (English)

    Hao ZHOU; Gary MUEHLBAUER; Brian STEFFENSON

    2012-01-01

    Cultivated barley is known to have a complex population structure and extensive linkage disequilibrium (LD).To conduct robust association mapping (AM) studies of economically important traits in US barley breeding germplasm,population structure and LD decay were examined in a complete panel of US barley breeding germplasm (3840 lines) genotyped with 3072 single nucleotide polymorphisms (SNPs).Nine subpopulations (sp1-sp9) were identified by the program STRUCTURE and subsequently confirmed by principle component analysis (PCA).Out of the nine subpopulations,seven were very similar to the respective subpopulations identified by Hamblin et al.(2010)which were based on half of the germplasm and half of the SN P markers,but two subpopulations were found to be new.One subpopulation was dominated by six-rowed spring lines from Utah State University (UT) and the other was composed of six-rowed spring lines from multiple breeding programs (USDA-ARS Aberdeen (AB),Busch Agricultural Resources Inc.(BA),UT,and Washington State University (WA)).LD was found to decay across a range from 4.0 to 19.8 cM.This result indicates that the germplasm genotyped with 3072 SNPs would be robust for mapping and possibly identifying the causal polymorphisms contributing to disease resistance and perhaps other traits.

  1. Uniting Superhydrophobic, Superoleophobic and Lubricant Infused Slippery Behavior on Copper Oxide Nano-structured Substrates

    Science.gov (United States)

    Ujjain, Sanjeev Kumar; Roy, Pritam Kumar; Kumar, Sumana; Singha, Subhash; Khare, Krishnacharya

    2016-10-01

    Alloys, specifically steel, are considered as the workhorse of our society and are inimitable engineering materials in the field of infrastructure, industry and possesses significant applications in our daily life. However, creating a robust synthetic metallic surface that repels various liquids has remained extremely challenging. The wettability of a solid surface is known to be governed by its geometric nano-/micro structure and the chemical composition. Here, we are demonstrating a facile and economical way to generate copper oxide micro-nano structures with spherical (0D), needle (1D) and hierarchical cauliflower (3D) morphologies on galvanized steel substrates using a simple chemical bath deposition method. These nano/micro textured steel surfaces, on subsequent coating of a low surface energy material display excellent superhydrophobic, superoleophobic and slippery behavior. Polydimethylsiloxane coated textured surfaces illustrate superhydrophobicity with water contact angle about 160°(2) and critical sliding angle ~2°. When functionalized with low-surface energy perfluoroalkylsilane, these surfaces display high repellency for low surface tension oils as well as hydrocarbons. Among them, the hierarchical cauliflower morphology exhibits re-entrant structure thereby showing the best superoleophobicity with contact angle 149° for dodecane. Once infused with a lubricant like silicone oil, they show excellent slippery behavior with low contact angle hysteresis (~ 2°) for water drops.

  2. Surface and Interface Properties of 10–12 Unit Cells Thick Sputter Deposited Epitaxial CeO2 Films

    Directory of Open Access Journals (Sweden)

    L. V. Saraf

    2008-01-01

    Full Text Available Ultrathin and continuous epitaxial films with relaxed lattice strain can potentially maintain more of its bulk physical and chemical properties and are useful as buffer layers. We study surface, interface, and microstructural properties of ultrathin (∼10–12 unit cells thick epitaxial ceria films grown on single crystal YSZ substrates. The out-of -plane and in-plane lattice parameters indicate relaxation in the continuous film due to misfit dislocations seen by high-resolution transmission electron microscopy (HRTEM and substrate roughness of ∼1-2 unit cells, confirmed by atomic force microscopy and HRTEM. A combination of secondary sputtering, lattice mismatch, substrate roughness, and surface reduction creating secondary phase was likely the cause of surface roughness which should be reduced to a minimum level for effective use of it as buffer layers.

  3. Compact Circularly Polarized Patch Antenna Using a Composite Right/Left-Handed Transmission Line Unit-Cell

    Directory of Open Access Journals (Sweden)

    L. Geng

    2013-04-01

    Full Text Available A compact circularly polarized (CP patch antenna using a composite right/left-handed (CRLH transmission line (TL unit-cell is proposed. The CRLH TL unit-cell includes a complementary split ring resonator (CSRR for shunt inductance and a gap loaded with a circular-shaped slot for series capacitance. The CSRR can decrease the TM10 mode resonance frequency, thus reducing the electrical size of the proposed antenna. In addition, the asymmetry of the CSRR brings about the TM01 mode, which can be combined with the TM10 mode by changing the slot radius. The combination of these two orthogonal modes with 90° phase shift makes the proposed antenna provide a CP property. The experimental results show that the proposed antenna has a wider axial ratio bandwidth and a smaller electrical size than the reported CP antennas. Moreover, the proposed antenna is designed without impedance transformer, 90° phase shift, dual feed and ground via.

  4. Proposal of a flexible structural-organizing model for the Intensive Care Units.

    Science.gov (United States)

    Iapichino, G; Radrizzani, D; Rossi, C; Pezzi, A; Anghileri, A; Boffelli, S; Giardino, M; Mistraletti, G; Bertolini, G

    2007-10-01

    The aim of this study was to verify the capability of the Italian Group for the Evaluation of Intervention in Intensive Care Medicine (Gruppo Italiano Valutazione Interventi in Terapia Intensiva, GiViTI) Intensive Care Units (ICUs) in providing high level care (HLC) and to develop a flexible organiziational model, allowing for different levels of care in each ICU. Once the number of active beds, personnel and technology of each ICU were determined, we computed whether the available bed number and all available resources could provide HLC according to international standards. For ICUs lacking staff or equipment for safe HLC in all declared beds, we calculated the best combination between HLC and observation/monitoring beds with less need for nurses and technology (low level of care, LLC) in order to optimise the utilization of each bed. We also investigated the work organisation of physicians and nurses in these units. There are 2 070 available beds in the 293 GiViTI ICUs. To provide HLC according to international criteria, the beds would decrease to 80.9%, because 144 ICUs do not have nurses or equipment to provide HLC in each bed. In order to maximize the suitable use of available resources, these ICUs would have to reduce the HLC bed number using the regained nurse workload for LLC. Because of this, the total number of HLC beds would further decrease to 65.9% of all declared beds. During Sundays and holidays, the bed/doctor and the bed/nurse ratios increase in most ICUs. To maximize the staff and equipment resources available, the bed numbers of a general ICU providing HLC must vary, even daily, according to the level of care provided. This level is not always high for all patients present. Applying this organizing model to each ICU, we could have enough flexibility to face the different demands for assistance if the ICU is built as a large open space to achieve the best clinical model and use of resources.

  5. Online estimation of internal stack temperatures in solid oxide fuel cell power generating units

    Science.gov (United States)

    Dolenc, B.; Vrečko, D.; Juričić, Ɖ.; Pohjoranta, A.; Pianese, C.

    2016-12-01

    Thermal stress is one of the main factors affecting the degradation rate of solid oxide fuel cell (SOFC) stacks. In order to mitigate the possibility of fatal thermal stress, stack temperatures and the corresponding thermal gradients need to be continuously controlled during operation. Due to the fact that in future commercial applications the use of temperature sensors embedded within the stack is impractical, the use of estimators appears to be a viable option. In this paper we present an efficient and consistent approach to data-driven design of the estimator for maximum and minimum stack temperatures intended (i) to be of high precision, (ii) to be simple to implement on conventional platforms like programmable logic controllers, and (iii) to maintain reliability in spite of degradation processes. By careful application of subspace identification, supported by physical arguments, we derive a simple estimator structure capable of producing estimates with 3% error irrespective of the evolving stack degradation. The degradation drift is handled without any explicit modelling. The approach is experimentally validated on a 10 kW SOFC system.

  6. Insights to the effects of free cells on community structure of attached cells and chalcopyrite bioleaching during different stages.

    Science.gov (United States)

    Feng, Shoushuai; Yang, Hailin; Wang, Wu

    2016-01-01

    The effects of free cells on community structure of attached cells and chalcopyrite bioleaching by Acidithiobacillus sp. during different stages were investigated. The attached cells of Acidithiobacillus thiooxidans owned the community advantage from 14thd to the end of bioprocess in the normal system. The community structure of attached cells was greatly influenced in the free cells-deficient systems. Compared to A. thiooxidans, the attached cells community of Acidithiobacillus ferrooxidans had a higher dependence on its free cells. Meanwhile, the analysis of key biochemical parameters revealed that the effects of free cells on chalcopyrite bioleaching in different stages were diverse, ranging from 32.8% to 64.3%. The bioleaching contribution of free cells of A. ferrooxidans in the stationary stage (8-14thd) was higher than those of A. thiooxidans, while the situation was gradually reversed in the jarosite passivation inhibited stage (26-40thd). These results may be useful in guiding chalcopyrite bioleaching.

  7. Interfacing of science, medicine and law: The stem cell patent controversy in the United States and the European Union

    Directory of Open Access Journals (Sweden)

    Sonya eDavey

    2015-11-01

    Full Text Available The patent eligibility of stem cells – particularly those derived from human embryos – has long been under debate in both the scientific and legal communities. On the basis of moral grounds, the European Patent Office (EPO has refrained from granting patents for stem cells obtained through the destruction of human embryos. On the contrary, the United States Patent and Trademark Office (USPTO has historically granted patents regarding the isolation and use of human embryonic and other stem cells. To date, these US patents remain valid despite an increasing onslaught of challenges in court. However, recent precedents established in US courts significantly narrow the scope of patent eligibility within biotechnology. This article compares the implications of recent legal changes on stem cell patent eligibility between the EU and US.

  8. PDI Derivative through Fine-Tuning Molecular Structure for Fullerene-Free Organic Solar Cells

    KAUST Repository

    Sun, Hua

    2017-08-10

    A perylenediimide (PDI)-based small molecular (SM) acceptor with both an extended π-conjugation and a three dimensional structure concurrently is critical for achieving high performance PDI-based fullerene-free organic solar cells (OSCs). In this work, we designed and synthesized a novel PDI-based SM acceptor possessing both characteristics by fusing PDI units with a spiro core of 4,4’-spirobi[cyclopenta[2,1-b;3,4-b’]dithiophene(SCPDT) through the -position of the thiophene rings. An enhanced strong absorption in the range of 350–520 nm and arisen LUMO energy level of FSP was observed, compared with previous reported acceptor SCPDT-PDI4, in which the PDI units and SCPDT are not fused. OSCs based on PTB7-Th donor and FSP acceptor were fabricated and achieved a power conversion efficiency of up to 8.89% with DPE as an additive. Efficient and complementary photo absorption, favorable phase separation and balanced carrier mobilites in the blend film account for the high photovoltaic performance. This study offers an effective strategy to design high performance PDI-based acceptors.

  9. Red cell storage age policy for patients with sickle cell disease: A survey of transfusion service directors in the United States.

    Science.gov (United States)

    Karafin, Matthew S; Singavi, Arun K; Irani, Mehraboon S; Puca, Kathleen E; Baumann Kreuziger, Lisa; Simpson, Pippa; Field, Joshua J

    2016-02-01

    In patients with sickle cell disease (SCD), the effects of the red cell storage lesion are not well defined. The objective of this study was to determine the prevalence of transfusion services that limit red cell units by storage age for patients with SCD. We developed a 22 question survey of transfusion service director opinions and their corresponding blood bank policies. Target subjects were systematically identified on the AABB website. Responses were recorded in SurveyMonkey and summarized using standard statistical techniques. Ninety transfusion service directors responded to the survey. Response rate was 22%. Only 23% of respondents had storage age policies in place for patients with SCD, even though 36% of respondents consider older units to be potentially harmful in this patient population. Of those with a policy, a less-than 15 day storage age requirement was most often used (75%), but practices varied, and most respondents (65%) agreed that evidence-based guidelines regarding storage age are needed for patients with SCD. Policies, practices and opinions about the risks of older units for patients with SCD vary. As patients with SCD may have unique susceptibilities to features of the red cell storage lesion, prospective studies in this population are needed to determine best practice.

  10. Purpose, structure, and function of the United States National Dental Practice-Based Research Network

    Science.gov (United States)

    Gilbert, Gregg H.; Williams, O. Dale; Korelitz, James J.; Fellows, Jeffrey L.; Gordan, Valeria V.; Makhija, Sonia K.; Meyerowitz, Cyril; Oates, Thomas W.; Rindal, D. Brad; Benjamin, Paul L.; Foy, Patrick J.

    2013-01-01

    Objective Following a successful2005–2012 phase with three regional practice-based research networks (PBRNs), a single, unified national network called “The National Dental PBRN” was created in 2012 in the United States to improve oral health by conducting practice-based research and serving dental professionals through education and collegiality. Methods Central administration is based in Alabama. Regional centres are based in Alabama, Florida, Minnesota, Oregon, New York and Texas, with a Coordinating Centre in Maryland. Ideas for studies are prioritized by the Executive Committee, comprised mostly of full-time clinicians. Results To date, 2736 persons have enrolled, from all six network regions; enrollment continues to expand. They represent a broad range of practitioners, practice types, and patient populations. Practitioners are actively improving every step of the research process, from idea generation, to study development, field testing, data collection, and presentation and publication. Conclusions Practitioners from diverse settings are partnering with fellow practitioners and academics to improve clinical practice and meet the needs of clinicians and their patients. Clinical significance This “nation’s network” aims to serve as a precious national resource to improve the scientific basis for clinical decision-making and foster movement of the latest evidence into routine practice. PMID:23597500

  11. Differences in hydraulic pressure producing efficiency of front suspension units for motorcycles due to structural difference

    Energy Technology Data Exchange (ETDEWEB)

    Kajino, Tsutomu; Namazue, Eitaro; Ueno, Yutaka

    1995-12-31

    The front suspension unit for motorcycles is one of the functional parts for which continuous engineering improvement is required for advanced driveability. Especially, the ones for off-road motocross racing are frequently required to have their energy absorbing properties, ability to maintain tire-to-ground contact, driving comfort, etc. to be improved to meet the challenges of the racing courses which include many jumps, to exceed the performance of competitors, and to match the ever-improving performance of the engines and frames. To cope with the situation, the operability, rigidity and hydraulic pressure producing mechanism needs to be upgraded. As part of an improvement program, the authors have developed a air-oil separated front suspension which the authors have called the ``twin chamber`` suspension. In this study, the authors compared the hydraulic pressure producing efficiency of the air-oil separated suspension with that of the conventional single chamber construction. The results of the comparison showed that the twin chamber suspension is less affected by the pressure hysteresis by 8% or more at the piston area and 50% or more at the partition area than the conventional suspension. In addition, for the twin chamber suspension, the rise of pressure becomes smoother to give a quicker response as the velocity increases.

  12. On the Effect of Unit-Cell Parameters in Predicting the Elastic Response of Wood-Plastic Composites

    Directory of Open Access Journals (Sweden)

    Fatemeh Alavi

    2013-01-01

    Full Text Available This paper presents a study on the effect of unit-cell geometrical parameters in predicting elastic properties of a typical wood plastic composite (WPC. The ultimate goal was obtaining the optimal values of representative volume element (RVE parameters to accurately predict the mechanical behavior of the WPC. For each unit cell, defined by a given combination of the above geometrical parameters, finite element simulation in ABAQUS was carried out, and the corresponding stress-strain curve was obtained. A uniaxial test according to ASTM D638-02a type V was performed on the composite specimen. Modulus of elasticity was determined using hyperbolic tangent function, and the results were compared to the sets of finite element analyses. Main effects of RVE parameters and their interactions were demonstrated and discussed, specially regarding the inclusion of two adjacent wood particles within one unit cell of the material. Regression analysis was performed to mathematically model the RVE parameter effects and their interactions over the modulus of elasticity response. The model was finally employed in an optimization analysis to arrive at an optimal set of RVE parameters that minimizes the difference between the predicted and experimental moduli of elasticity.

  13. Intra-unit-cell magnetic correlations near optimal doping in YBa2Cu3O6.85.

    Science.gov (United States)

    Mangin-Thro, L; Sidis, Y; Wildes, A; Bourges, P

    2015-07-03

    The pseudo-gap phenomenon in copper oxide superconductors is central to any description of these materials as it prefigures the superconducting state itself. A magnetic intra-unit-cell order was found to occur just at the pseudo-gap temperature in four cuprate high-Tc superconducting families. Here we present polarized neutron-scattering measurements of nearly optimally doped YBa2Cu3O6.85, carried out on two different spectrometers, that reveal several features. The intra-unit-cell order consists of finite-sized planar domains that are very weakly correlated along the c axis. At high temperature, only the out-of-plane magnetic components correlate, indicating a strong Ising anisotropy. An aditional in-plane response develops at low temperature, giving rise to an apparent tilt of the magnetic moment. The discovery of these two regimes puts stringent constraints, which are tightly bound to the pseudo-gap physics, on the intrinsic nature of intra-unit-cell order.

  14. Efficiency in the United States electric industry: Transaction costs, deregulation, and governance structures

    Science.gov (United States)

    Peterson, Carl

    Transaction costs economics (TCE) posits that firms have an incentive to bypass the market mechanisms in situations where the cost of using the market is prohibitive. Vertical integration, among other governance mechanisms, can be used to minimize the transactions costs associated with the market mechanism. The study analyses different governance mechanisms, which range from complete vertical integration to the use of market mechanisms, for firms in the US electric sector. This sector has undergone tremendous change in the past decade including the introduction of retail competition in some jurisdictions. As a result of the push toward deregulation of the industry, vertically integration, while still significant in the sector, has steadily been replaced by alternative governance structures. Using a sample of 136 investor-owned electric utilities that reported data the US Federal Energy Regulatory Commission between 1996 and 2002, this study estimates firm level efficiency using Data Envelopment Analysis (DEA) and relates these estimates to governance structure and public policies. The analysis finds that vertical integration is positively related to firm efficiency, although in a non-linear fashion suggesting that hybrid governance structures tend to be associated with lower efficiency scores. In addition, while some evidence is found for negative short-term effects on firm efficiency from the choice to deregulate, this result is sensitive to DEA model choice. Further, competition in retail markets is found to be positively related to firm level efficiency, but the retreat from deregulation, which occurred after 2000, is negatively associated with firm-level efficiency. These results are important in the ongoing academic and public policy debates concerning deregulation of the electric section and indicate that vertical economies remain in the industry, but that competition has provided incentives for improving firm level efficiency.

  15. Architecture of digital signal’s processing units with the rebuildable structure

    Directory of Open Access Journals (Sweden)

    Sheik-Seikin A. N.

    2011-08-01

    Full Text Available The synthesis technique is developed for the computing system architecture with tunable structure with graph of information connections (GIC affine transformations which assumes additional equipment of initial computing system (CS with the appropriate switching system implementing, depending on character of GIC change, one of the methods of block reorganization providing effective implementation of CS in wide range of GIC parameters change. The received estimations of hardware expenses for various methods of reorganization allow to define efficiency of CS implementation for each specific case.

  16. Window into the Caledonian orogen: Structure of the crust beneath the East Shetland platform, United Kingdom

    Science.gov (United States)

    McBride, J.H.; England, R.W.

    1999-01-01

    Reprocessing and interpretation of commercial and deep seismic reflection data across the East Shetland platform and its North Sea margin provide a new view of crustal subbasement structure beneath a poorly known region of the British Caledonian orogen. The East Shetland platform, east of the Great Glen strike-slip fault system, is one of the few areas of the offshore British Caledonides that remained relatively insulated from the Mesozoic and later rifting that involved much of the area around the British Isles, thus providing an "acoustic window" into the deep structure of the orogen. Interpretation of the reflection data suggests that the crust beneath the platform retains a significant amount of its original Caledonian and older architecture. The upper to middle crust is typically poorly reflective except for individual prominent dipping reflectors with complex orientations that decrease in dip with depth and merge with a lower crustal layer of high reflectivity. The three-dimensional structural orientation of the reflectors beneath the East Shetland platform is at variance with Caledonian reflector trends observed elsewhere in the Caledonian orogen (e.g., north of the Scottish mainland), emphasizing the unique tectonic character of this part of the orogen. Upper to middle crustal reflectors are interpreted as Caledonian or older thrust surfaces that were possibly reactivated by Devonian extension associated with post-Caledonian orogenic collapse. The appearance of two levels of uneven and diffractive (i.e., corrugated) reflectivity in the lower crust, best developed on east-west-oriented profiles, is characteristic of the East Shetland platform. However, a north-south-oriented profile reveals an interpreted south-vergent folded and imbricated thrust structure in the lower crust that appears to be tied to the two levels of corrugated reflectivity on the east-west profiles. A thrust-belt origin for lower crustal reflectivity would explain its corrugated

  17. Structural change of the physical economy. Decomposition analysis of physical and hybrid-unit input-output tables

    Energy Technology Data Exchange (ETDEWEB)

    Hoekstra, R.

    2003-10-01

    Economic processes generate a variety of material flows, which cause resource problems through the depletion of natural resources and environmental issues due to the emission of pollutants. This thesis presents an analytical method to study the relationship between the monetary economy and the 'physical economy'. In particular, this method can assess the impact of structural change in the economy on physical throughput. The starting point for the approach is the development of an elaborate version of the physical input-output table (PIOT), which acts as an economic-environmental accounting framework for the physical economy. In the empirical application, hybrid-unit input-output (I/O) tables, which combine physical and monetary information, are constructed for iron and steel, and plastic products for the Netherlands for the years 1990 and 1997. The impact of structural change on material flows is analyzed using Structural Decomposition Analysis (SDA), whic specifies effects such as sectoral shifts, technological change, and alterations in consumer spending and international trade patterns. The study thoroughly reviews the application of SDA to environmental issues, compares the method with other decomposition methods, and develops new mathematical specifications. An SDA is performed using the hybrid-unit input-output tables for the Netherlands. The results are subsequently used in novel forecasting and backcasting scenario analyses for the period 1997-2030. The results show that dematerialization of iron and steel, and plastics, has generally not occurred in the recent past (1990-1997), and will not occur, under a wide variety of scenario assumptions, in the future (1997-2030)

  18. Structural basis for the enhanced stability of protein model compounds and peptide backbone unit in ammonium ionic liquids.

    Science.gov (United States)

    Vasantha, T; Attri, Pankaj; Venkatesu, Pannuru; Devi, R S Rama

    2012-10-04

    Protein folding/unfolding is a fascinating study in the presence of cosolvents, which protect/disrupt the native structure of protein, respectively. The structure and stability of proteins and their functional groups may be modulated by the addition of cosolvents. Ionic liquids (ILs) are finding a vast array of applications as novel cosolvents for a wide variety of biochemical processes that include protein folding. Here, the systematic and quantitative apparent transfer free energies (ΔG'(tr)) of protein model compounds from water to ILs through solubility measurements as a function of IL concentration at 25 °C have been exploited to quantify and interpret biomolecular interactions between model compounds of glycine peptides (GPs) with ammonium based ILs. The investigated aqueous systems consist of zwitterionic glycine peptides: glycine (Gly), diglycine (Gly(2)), triglycine (Gly(3)), tetraglycine (Gly(4)), and cyclic glycylglycine (c(GG)) in the presence of six ILs such as diethylammonium acetate (DEAA), diethylammonium hydrogen sulfate (DEAS), triethylammonium acetate (TEAA), triethylammonium hydrogen sulfate (TEAS), triethylammonium dihydrogen phosphate (TEAP), and trimethylammonium acetate (TMAA). We have observed positive values of ΔG'(tr) for GPs from water to ILs, indicating that interactions between ILs and GPs are unfavorable, which leads to stabilization of the structure of model protein compounds. Moreover, our experimental data ΔG'(tr) is used to obtain transfer free energies (Δg'(tr)) of the peptide backbone unit (or glycyl unit) (-CH(2)C═ONH-), which is the most numerous group in globular proteins, from water to IL solutions. To obtain the mechanism events of the ILs' role in enhancing the stability of the model compounds, we have further obtained m-values for GPs from solubility limits. These results explicitly elucidate that all alkyl ammonium ILs act as stabilizers for model compounds through the exclusion of ILs from model compounds of

  19. Genetic structure and molecular variability of Cucumber mosaic virus isolates in the United States.

    Directory of Open Access Journals (Sweden)

    Shahideh Nouri

    Full Text Available Cucumber mosaic virus (CMV has a worldwide distribution and the widest host range of any known plant virus. From 2000 to 2012, epidemics of CMV severely affected the production of snap bean (Phaseulos vulgaris L. in the Midwest and Northeastern United States. Virus diversity leading to emergence of new strains is often considered a significant factor in virus epidemics. In addition to epidemics, new disease phenotypes arising from genetic exchanges or mutation can compromise effectiveness of plant disease management strategies. Here, we captured a snapshot of genetic variation of 32 CMV isolates collected from different regions of the U.S including new field as well as historic isolates. Nucleotide diversity (π was low for U.S. CMV isolates. Sequence and phylogenetic analyses revealed that CMV subgroup I is predominant in the US and further showed that the CMV population is a mixture of subgroups IA and IB. Furthermore, phylogenetic analysis suggests likely reassortment between subgroups IA and IB within five CMV isolates. Based on phylogenetic and computational analysis, recombination between subgroups I and II as well as IA and IB in RNA 3 was detected. This is the first report of recombination between CMV subgroups I and II. Neutrality tests illustrated that negative selection was the major force operating upon the CMV genome, although some positively selected sites were detected for all encoded proteins. Together, these data suggest that different regions of the CMV genome are under different evolutionary constraints. These results also delineate composition of the CMV population in the US, and further suggest that recombination and reassortment among strain subgroups does occur but at a low frequency, and point towards CMV genomic regions that differ in types of selection pressure.

  20. Generalizable items and modular structure for computerised physician staffing calculation on intensive care units.

    Science.gov (United States)

    Weiss, Manfred; Marx, Gernot; Iber, Thomas

    2017-08-04

    Intensive care medicine remains one of the most cost-driving areas within hospitals with high personnel costs. Under the scope of limited budgets and reimbursement, realistic needs are essential to justify personnel staffing. Unfortunately, all existing staffing models are top-down calculations with a high variability in results. We present a workload-oriented model, integrating quality of care, efficiency of processes, legal, educational, controlling, local, organisational and economic aspects. In our model, the physician's workload solely related to the intensive care unit depends on three tasks: Patient-oriented tasks, divided in basic tasks (performed in every patient) and additional tasks (necessary in patients with specific diagnostic and therapeutic requirements depending on their specific illness, only), and non patient-oriented tasks. All three tasks have to be taken into account for calculating the required number of physicians. The calculation tool further allows to determine minimal personnel staffing, distribution of calculated personnel demand regarding type of employee due to working hours per year, shift work or standby duty. This model was introduced and described first by the German Board of Anesthesiologists and the German Society of Anesthesiology and Intensive Care Medicine in 2008 and since has been implemented and updated 2012 in Germany. The modular, flexible nature of the Excel-based calculation tool should allow adaption to the respective legal and organizational demands of different countries. After 8 years of experience with this calculation, we report the generalizable key aspects which may help physicians all around the world to justify realistic workload-oriented personnel staffing needs.

  1. Structural characterization of the acid-degraded secondary cell wall polymer of Geobacillus stearothermophilus PV72/p2.

    Science.gov (United States)

    Petersen, Bent O; Sára, Margit; Mader, Christoph; Mayer, Harald F; Sleytr, Uwe B; Pabst, Martin; Puchberger, Michael; Krause, Eberhard; Hofinger, Andreas; Duus, Jens Ø; Kosma, Paul

    2008-06-09

    The secondary cell wall polymer (SCWP) from Geobacillus stearothermophilus PV72/p2, which is involved in the anchoring of the surface-layer protein to the bacterial cell wall layer, is composed of 2-amino-2-deoxy- and 2-acetamido-2-deoxy-D-glucose, 2-acetamido-2-deoxy-D-mannose, and 2-acetamido-2-deoxy-D-mannuronic acid. The primary structure of the acid-degraded polysaccharide--liberated by HF-treatment from the cell wall--was determined by high-field NMR spectroscopy and mass spectrometry using N-acetylated and hydrolyzed polysaccharide derivatives as well as Smith-degradation. The polysaccharide was shown to consist of a tetrasaccharide repeating unit containing a pyruvic acid acetal at a side-chain 2-acetamido-2-deoxy-alpha-D-mannopyranosyl residue. Substoichiometric substitutions of the repeating unit were observed concerning the degree of N-acetylation of glucosamine residues and the presence of side-chain linked 2-acetamido-2-deoxy-beta-D-glucopyranosyl units: [Formula: see text].

  2. Cell surface structures influence lung clearance rate of systemically infused mesenchymal stromal cells.

    Science.gov (United States)

    Nystedt, Johanna; Anderson, Heidi; Tikkanen, Jonne; Pietilä, Mika; Hirvonen, Tia; Takalo, Reijo; Heiskanen, Annamari; Satomaa, Tero; Natunen, Suvi; Lehtonen, Siri; Hakkarainen, Tanja; Korhonen, Matti; Laitinen, Saara; Valmu, Leena; Lehenkari, Petri

    2013-02-01

    The promising clinical effects of mesenchymal stromal/stem cells (MSCs) rely especially on paracrine and nonimmunogenic mechanisms. Delivery routes are essential for the efficacy of cell therapy and systemic delivery by infusion is the obvious goal for many forms of MSC therapy. Lung adhesion of MSCs might, however, be a major obstacle yet to overcome. Current knowledge does not allow us to make sound conclusions whether MSC lung entrapment is harmful or beneficial, and thus we wanted to explore MSC lung adhesion in greater detail. We found a striking difference in the lung clearance rate of systemically infused MSCs derived from two different clinical sources, namely bone marrow (BM-MSCs) and umbilical cord blood (UCB-MSCs). The BM-MSCs and UCB-MSCs used in this study differed in cell size, but our results also indicated other mechanisms behind the lung adherence. A detailed analysis of the cell surface profiles revealed differences in the expression of relevant adhesion molecules. The UCB-MSCs had higher expression levels of α4 integrin (CD49d, VLA-4), α6 integrin (CD49f, VLA-6), and the hepatocyte growth factor receptor (c-Met) and a higher general fucosylation level. Strikingly, the level of CD49d and CD49f expression could be functionally linked with the lung clearance rate. Additionally, we saw a possible link between MSC lung adherence and higher fibronectin expression and we show that the expression of fibronectin increases with MSC culture confluence. Future studies should aim at developing methods of transiently modifying the cell surface structures in order to improve the delivery of therapeutic cells.

  3. Prevalence of heterotypic tumor/immune cell-in-cell structure in vitro and in vivo leading to formation of aneuploidy.

    Directory of Open Access Journals (Sweden)

    Yu-hui Chen

    Full Text Available Cell-in-cell structures refer to a unique phenomenon that one living cell enters into another living cell intactly, occurring between homotypic tumor cells or tumor (or other tissue cells and immune cells (named as heterotypic cell-in-cell structure. In the present study, through a large scale of survey we observed that heterotypic cell-in-cell structure formation occurred commonly in vitro with host cells derived from different human carcinomas as well as xenotypic mouse tumor cell lines. Most of the lineages of human immune cells, including T, B, NK cells, monocytes as well as in vitro activated LAK cells, were able to invade tumor cell lines. Poorly differentiated stem cells were capable of internalizing immune cells as well. More significantly, heterotypic tumor/immune cell-in-cell structures were observed in a higher frequency in tumor-derived tissues than those in adjacent tissues. In mouse hepatitis models, heterotypic immune cell/hepatocyte cell-in-cell structures were also formed in a higher frequency than in normal controls. After in vitro culture, different forms of internalized immune cells in heterotypic cell-in-cell structures were observed, with one or multiple immune cells inside host cells undergoing resting, degradation or mitosis. More strikingly, some internalized immune cells penetrated directly into the nucleus of target cells. Multinuclear cells with aneuploid nucleus were formed in target tumor cells after internalizing immune cells as well as in situ tumor regions. Therefore, with the prevalence of heterotypic cell-in-cell structures observed, we suggest that shielding of immune cells inside tumor or inflammatory tissue cells implies the formation of aneuploidy with the increased multinucleation as well as fine-tuning of microenvironment under pathological status, which may define distinct mechanisms to influence the etiology and progress of tumors.

  4. A novel organic-inorganic hybrid tandem solar cell with inverted structure

    Science.gov (United States)

    Bahrami, A.; Faez, R.

    2017-04-01

    A novel organic-inorganic hybrid tandem solar cell with inverted structure is proposed. This efficient double-junction hybrid tandem solar cell consists of a single-junction hydrogenated amorphous silicon (a-Si:H) subcell with n-i-p structure as front cell and a P3HT:PCBM organic subcell with inverted structure as back cell. In order to optimize the hybrid tandem cell, we have performed a simulation based on transfer matrix method. We have compared the characteristics of this novel structure with a conventional structure. As a result, a power conversion efficiency (PCE) of 6.1 and 24% improvement compared to the conventional hybrid tandem cell was achieved. We also discuss the high potential of this novel structure for realizing high-stability organic-inorganic hybrid photovoltaic devices.

  5. Fuel Cell Backup Power Unit Configuration and Electricity Market Participation: A Feasibility Study

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Zhiwen [National Renewable Energy Lab. (NREL), Golden, CO (United States); Eichman, Josh [National Renewable Energy Lab. (NREL), Golden, CO (United States); Kurtz, Jennifer [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2017-03-13

    This National Renewable Energy Laboratory industry-inspired Laboratory Directed Research and Development project evaluates the feasibility and economics of using fuel cell backup power systems in cell towers to provide grid services (e.g., balancing, ancillary services, demand response). The work is intended to evaluate the integration of thousands of under-utilized, clean, efficient, and reliable fuel cell systems that are already installed in cell towers for potential grid and ancillary services.

  6. 3D Bearing Capacity of Structured Cells Supported on Cohesive Soil: Simplified Analysis Method

    Directory of Open Access Journals (Sweden)

    Martínez-Galván Sergio Antonio

    2013-06-01

    Full Text Available In this paper a simplified analysis method to compute the bearing capacity of structured cell foundations subjected to vertical loading and supported in soft cohesive soil is proposed. A structured cell is comprised by a top concrete slab structurally connected to concrete external walls that enclose the natural soil. Contrary to a box foundation it does not include a bottom slab and hence, the soil within the walls becomes an important component of the structured cell. This simplified method considers the three-dimensional geometry of the cell, the undrained shear strength of cohesive soils and the existence of structural continuity between the top concrete slab and the surrounding walls, along the walls themselves and the walls structural joints. The method was developed from results of numerical-parametric analyses, from which it was found that structured cells fail according to a punching-type mechanism.

  7. Genetic Structure of the Invasive Tree Ailanthus altissima in Eastern United States Cities

    Directory of Open Access Journals (Sweden)

    Preston R. Aldrich

    2010-01-01

    Full Text Available Ailanthus altissima is an invasive tree from Asia. It now occurs in most US states, and although primarily an urban weed, it has become a problem in forested areas especially in the eastern states. Little is known about its genetic structure. We explore its naturalized gene pool from 28 populations, mostly of the eastern US where infestations are especially severe. Five microsatellite markers were used to examine presumed neutral genetic variation. Results show a gene pool that is moderately diverse and sexually active and has significant but small genetic differences among populations and little correspondence between geographic and genetic distance. These findings are consistent with a model of multiple introductions followed by high rates of gene exchange between cities and regions. We propose movement along road and railway systems as the chief mode of range expansion.

  8. Observations on Faults and Associated Permeability Structures in Hydrogeologic Units at the Nevada Test Site

    Energy Technology Data Exchange (ETDEWEB)

    Prothro, Lance B.; Drellack, Sigmund L.; Haugstad, Dawn N.; Huckins-Gang, Heather E.; Townsend, Margaret J.

    2009-03-30

    Observational data on Nevada Test Site (NTS) faults were gathered from a variety of sources, including surface and tunnel exposures, core samples, geophysical logs, and down-hole cameras. These data show that NTS fault characteristics and fault zone permeability structures are similar to those of faults studied in other regions. Faults at the NTS form complex and heterogeneous fault zones with flow properties that vary in both space and time. Flow property variability within fault zones can be broken down into four major components that allow for the development of a simplified, first approximation model of NTS fault zones. This conceptual model can be used as a general guide during development and evaluation of groundwater flow and contaminate transport models at the NTS.

  9. Distribution of transformed organic matter in structural units of loamy sandy soddy-podzolic soil

    Science.gov (United States)

    Kogut, B. M.; Yashin, M. A.; Semenov, V. M.; Avdeeva, T. N.; Markina, L. G.; Lukin, S. M.; Tarasov, S. I.

    2016-01-01

    The effect of land use types and fertilizing systems on the structural and aggregate composition of loamy sandy soddy-podzolic soil and the quantitative parameters of soil organic matter has been studied. The contribution of soil aggregates 2-1 mm in size to the total Corg reserve in the humus horizon is higher than the contributions of other aggregates by 1.3-4.2 times. Reliable correlations have been revealed between the contents of total (Corg), labile (Clab), and active (C0) organic matter in the soil. The proportion of C0 is 44-70% of Clab extractable by neutral sodium pyrophosphate solution. The contributions of each of the 2-1, 0.5-0.25, and humus horizon of loamy sandy soddy-podzolic soil, the active, slow, and passive pools contain 6-11, 34-65, and 26-94% of the total Corg, respectively.

  10. Kidney specific protein-positive cells derived from embryonic stem cells reproduce tubular structures in vitro and differentiate into renal tubular cells.

    Science.gov (United States)

    Morizane, Ryuji; Monkawa, Toshiaki; Fujii, Shizuka; Yamaguchi, Shintaro; Homma, Koichiro; Matsuzaki, Yumi; Okano, Hideyuki; Itoh, Hiroshi

    2014-01-01

    Embryonic stem cells and induced pluripotent stem cells have the ability to differentiate into various organs and tissues, and are regarded as new tools for the elucidation of disease mechanisms as well as sources for regenerative therapies. However, a method of inducing organ-specific cells from pluripotent stem cells is urgently needed. Although many scientists have been developing methods to induce various organ-specific cells from pluripotent stem cells, renal lineage cells have yet to be induced in vitro because of the complexity of kidney structures and the diversity of kidney-component cells. Here, we describe a method of inducing renal tubular cells from mouse embryonic stem cells via the cell purification of kidney specific protein (KSP)-positive cells using an anti-KSP antibody. The global gene expression profiles of KSP-positive cells derived from ES cells exhibited characteristics similar to those of cells in the developing kidney, and KSP-positive cells had the capacity to form tubular structures resembling renal tubular cells when grown in a 3D culture in Matrigel. Moreover, our results indicated that KSP-positive cells acquired the characteristics of each segment of renal tubular cells through tubular formation when stimulated with Wnt4. This method is an important step toward kidney disease research using pluripotent stem cells, and the development of kidney regeneration therapies.

  11. Cdc42-dependent structural development of auditory supporting cells is required for wound healing at adulthood

    DEFF Research Database (Denmark)

    Anttonen, Tommi; Kirjavainen, Anna; Belevich, Ilya

    2012-01-01

    Cdc42 regulates the initial establishment of cytoskeletal and junctional structures, but only little is known about its role at later stages of cellular differentiation. We studied Cdc42's role in vivo in auditory supporting cells, epithelial cells with high structural complexity. Cdc42 inactivat......, a process that is critical to scar formation. Thus, Cdc42 is required for structural differentiation of auditory supporting cells and this proper maturation is necessary for wound healing in adults....

  12. Novel hydroxyamides and amides containing D-glucopyranose or D-fructose units: Biological assays in MCF-7 and MDST8 cell lines.

    Science.gov (United States)

    Carreiro, Elisabete P; Costa, Ana R; Cordeiro, Maria M; Martins, Rute; Pires, Tiago O; Saraiva, Mafalda; Antunes, Célia M; Burke, Anthony J

    2016-02-01

    A novel library of 15 compounds, hydroxyamides and amides containing a β-D-glucopyranose (D-Gluc) or a β-D-fructose (D-Fruc) units was designed and synthesized for antiproliferative assays in breast (MCF-7) and colon (MDST8) cancer cell lines. Twelve of them were hydroxyamides and were successfully synthesized from β-D-glucuronic acid (D-GluA). Six of these hydroxyamides which were acetylated hydroxy-β-D-glucopyranuronamide 2a-2f (1st Family) and the other six were their respective isomers, that is, hydroxy-β-D-fructuronamide 3a-3f (2nd Family), obtained by acid-base catalyzed isomerization. These compounds have the general structure, D-Gluc-C=ONH-CHR-(CH2)n-OH and D-Fruc-C=ONH-CHR-(CH2)n-OH, where R=an aromatic, alkyl or a hydrogen substituent, with n=0 or 1. Eight of these contained a chiral aminoalcohol group. Three compounds were amides containing a D-glucopyranose unit (3rd Family). SAR studies were conducted with these compounds. Antiproliferative studies showed that compound 4a, the bromo-amide containing the β-D-glucopyranose ring, potently inhibits the proliferation of the MDST8 cells. Five compounds (2e, 2f, 3d, 3e, and 3f) were shown to potently selectively inhibit the proliferation of the MCF-7 cells. Compound 4b was the only one showing inhibition in both cell lines. In general, the more active compounds were the amides and hydroxyamides containing the β-D-fructose moiety, and containing an alkyl group or hydrogen. Half-inhibitory concentrations (IC50) of between 0.01 and 10 μM, were observed.

  13. Structure of ristocetin A in complex with a bacterial cell-wall mimetic

    OpenAIRE

    Nahoum, Virginie; Spector, Sherri; Loll, Patrick J.

    2009-01-01

    The crystal structure of the complex between ristocetin A and the cell-wall peptide mimetic N-acetyl-lysine-d-alanine-d-alanine has been solved. Structural details explaining the anticooperativity of the antibiotic have been identified.

  14. Structured Ordinary Least Squares: A Sufficient Dimension Reduction approach for regressions with partitioned predictors and heterogeneous units.

    Science.gov (United States)

    Liu, Yang; Chiaromonte, Francesca; Li, Bing

    2017-06-01

    In many scientific and engineering fields, advanced experimental and computing technologies are producing data that are not just high dimensional, but also internally structured. For instance, statistical units may have heterogeneous origins from distinct studies or subpopulations, and features may be naturally partitioned based on experimental platforms generating them, or on information available about their roles in a given phenomenon. In a regression analysis, exploiting this known structure in the predictor dimension reduction stage that precedes modeling can be an effective way to integrate diverse data. To pursue this, we propose a novel Sufficient Dimension Reduction (SDR) approach that we call structured Ordinary Least Squares (sOLS). This combines ideas from existing SDR literature to merge reductions performed within groups of samples and/or predictors. In particular, it leads to a version of OLS for grouped predictors that requires far less computation than recently proposed groupwise SDR procedures, and provides an informal yet effective variable selection tool in these settings. We demonstrate the performance of sOLS by simulation and present a first application to genomic data. The R package "sSDR," publicly available on CRAN, includes all procedures necessary to implement the sOLS approach. © 2016, The International Biometric Society.

  15. Regulatory T Cells in Tumor-Associated Tertiary Lymphoid Structures Suppress Anti-tumor T Cell Responses.

    Science.gov (United States)

    Joshi, Nikhil S; Akama-Garren, Elliot H; Lu, Yisi; Lee, Da-Yae; Chang, Gregory P; Li, Amy; DuPage, Michel; Tammela, Tuomas; Kerper, Natanya R; Farago, Anna F; Robbins, Rebecca; Crowley, Denise M; Bronson, Roderick T; Jacks, Tyler

    2015-09-15

    Infiltration of regulatory T (Treg) cells into many tumor types correlates with poor patient prognoses. However, mechanisms of intratumoral Treg cell function remain to be elucidated. We investigated Treg cell function in a genetically engineered mouse model of lung adenocarcinoma and found that Treg cells suppressed anti-tumor responses in tumor-associated tertiary lymphoid structures (TA-TLSs). TA-TLSs have been described in human lung cancers, but their function remains to be determined. TLSs in this model were spatially associated with >90% of tumors and facilitated interactions between T cells and tumor-antigen-presenting dendritic cells (DCs). Costimulatory ligand expression by DCs and T cell proliferation rates increased in TA-TLSs upon Treg cell depletion, leading to tumor destruction. Thus, we propose that Treg cells in TA-TLSs can inhibit endogenous immune responses against tumors, and targeting these cells might provide therapeutic benefit for cancer patients.

  16. Three-dimensional reconstruction of single-cell chromosome structure using recurrence plots

    Science.gov (United States)

    Hirata, Yoshito; Oda, Arisa; Ohta, Kunihiro; Aihara, Kazuyuki

    2016-10-01

    Single-cell analysis of the three-dimensional (3D) chromosome structure can reveal cell-to-cell variability in genome activities. Here, we propose to apply recurrence plots, a mathematical method of nonlinear time series analysis, to reconstruct the 3D chromosome structure of a single cell based on information of chromosomal contacts from genome-wide chromosome conformation capture (Hi-C) data. This recurrence plot-based reconstruction (RPR) method enables rapid reconstruction of a unique structure in single cells, even from incomplete Hi-C information.

  17. Analysis and recognition of touching cell images based on morphological structures.

    Science.gov (United States)

    Yu, Donggang; Pham, Tuan D; Zhou, Xiaobo

    2009-01-01

    Automated analysis and recognition of cell-nuclear phases using fluorescence microscopy images play an important role for high-content screening. A major task of automated imaging based high-content screening is to segment and reconstruct each cell from the touching cell images. In this paper we present new useful method for recognizing morphological structural models of touching cells, detecting segmentation points, determining the number of segmented cells in touching cell image, finding the related data of segmented cell arcs and reconstructing segmented cells. The conceptual frameworks are based on the morphological structures where a series of structural points and their morphological relationships are established. Experiment results have shown the efficient application of the new method for analysis and recognition of touching cell images of high-content screening.

  18. Problematics of stress-strain state research in units of metal structures

    Directory of Open Access Journals (Sweden)

    Morozova Dina Vol'demarovna

    2014-05-01

    Full Text Available The article describes the experimental methods of determining stress-strain state of elements and structures with a brief description of the essence of each method. The authors focus mostly on polarization-optical method for determining stresses in the translucent optical sensing models made of epoxy resins. Physical component of the method is described in the article and a simple diagram of a circular polariscope is presented, as well as an example of the resulting interference pattern in illuminated monochromatic light. A polariscope, in its most general definition, consists of two polarizers. The polarizers sandwich a material or object of interest, and allows one to view the changes of the polarity of light passing through the material or object. Since we are unable to perceive the polarity of light with the naked eye, we are forced to use polariscopes to view the changes in polarity caused by the temporary birefringence of our photoelastic materials. A polariscope is constructed of two polarizers, each set perpendicular to the path of light transmitted through the setup. The first polarizer is called the "polarizer", and the second polarizer is called the "analyzer". The method how the polarizer works is quite simple: unpolarized light enters the polariscope through the polarizer, which allows through only the light of its orientation. This light then passes through the material under observation, and experiences some change in polarity. Finally, this light reaches the analyzer, which, like the polarizer, only lets the light of its orientation through.

  19. Structural elucidation and physicochemical properties of mononuclear Uranyl(VI) complexes incorporating dianionic units

    Science.gov (United States)

    Azam, Mohammad; Velmurugan, Gunasekaran; Wabaidur, Saikh Mohammad; Trzesowska-Kruszynska, Agata; Kruszynski, Rafal; Al-Resayes, Saud I.; Al-Othman, Zeid A.; Venuvanalingam, Ponnambalam

    2016-01-01

    Two derivatives of organouranyl mononuclear complexes [UO2(L)THF] (1) and [UO2(L)Alc] (2), where L = (2,2′-(1E,1′E)-(2,2-dimethylpropane-1,3-dyl)bis(azanylylidene, THF = Tetrahydrofuran, Alc = Alcohol), have been prepared. These complexes have been determined by elemental analyses, single crystal X-ray crystallography and various spectroscopic studies. Moreover, the structure of these complexes have also been studied by DFT and time dependent DFT measurements showing that both the complexes have distorted pentagonal bipyramidal environment around uranyl ion. TD-DFT results indicate that the complex 1 displays an intense band at 458.7 nm which is mainly associated to the uranyl centered LMCT, where complex 2 shows a band at 461.8 nm that have significant LMCT character. The bonding has been further analyzed by EDA and NBO. The photocatalytic activity of complexes 1 and 2 for the degradation of rhodamine-B (RhB) and methylene blue (MB) under the irradiation of 500W Xe lamp has been explored, and found more efficient in presence of complex 1 than complex 2 for both dyes. In addition, dye adsorption and photoluminescence properties have also been discussed for both complexes. PMID:27595801

  20. Structural elucidation and physicochemical properties of mononuclear Uranyl(VI) complexes incorporating dianionic units

    Science.gov (United States)

    Azam, Mohammad; Velmurugan, Gunasekaran; Wabaidur, Saikh Mohammad; Trzesowska-Kruszynska, Agata; Kruszynski, Rafal; Al-Resayes, Saud I.; Al-Othman, Zeid A.; Venuvanalingam, Ponnambalam

    2016-09-01

    Two derivatives of organouranyl mononuclear complexes [UO2(L)THF] (1) and [UO2(L)Alc] (2), where L = (2,2‧-(1E,1‧E)-(2,2-dimethylpropane-1,3-dyl)bis(azanylylidene, THF = Tetrahydrofuran, Alc = Alcohol), have been prepared. These complexes have been determined by elemental analyses, single crystal X-ray crystallography and various spectroscopic studies. Moreover, the structure of these complexes have also been studied by DFT and time dependent DFT measurements showing that both the complexes have distorted pentagonal bipyramidal environment around uranyl ion. TD-DFT results indicate that the complex 1 displays an intense band at 458.7 nm which is mainly associated to the uranyl centered LMCT, where complex 2 shows a band at 461.8 nm that have significant LMCT character. The bonding has been further analyzed by EDA and NBO. The photocatalytic activity of complexes 1 and 2 for the degradation of rhodamine-B (RhB) and methylene blue (MB) under the irradiation of 500W Xe lamp has been explored, and found more efficient in presence of complex 1 than complex 2 for both dyes. In addition, dye adsorption and photoluminescence properties have also been discussed for both complexes.

  1. Prevalence of roll-over protective structure (ROPS)-equipped tractors on Hispanic-operated farms in the United States.

    Science.gov (United States)

    Myers, John R

    2010-04-01

    Roll-over protective structures (ROPS) are known to prevent tractor overturn deaths, but not enough tractors are equipped with them in the United States to reduce the rate of these deaths to levels seen in several European countries. Recent literature has defined the use of ROPS on US farms in general, but little is known about ROPS use on Hispanic farm operations. Data from a national survey for the calendar year 2003 were used to assess the prevalence of ROPS use on Hispanic-operated farms. Farm characteristics previously identified to be associated with low ROPS prevalence rates on other farming operations were examined for these Hispanic farming operations. The overall ROPS prevalence rate on Hispanic farms was 52.2%. Adjusted odds ratios of potential risk factors found that the region where the farm was located and the acreage of the farm appeared to be the most significant indicators of the prevalence of ROPS on Hispanic farms. In addition, the age of the farm operator, the farm status as a full- or part-time operation, and the type of farm operation were also important factors. These findings were similar to those seen for racial minority farms and the general farming population. These results can be used to target ROPS promotion programs for Hispanic farmers across the United States.

  2. Poly(meta-phenylene) Derivative with Rigid Twisted Biphenyl Units in Backbone: Synthesis, Structural Characterization,Photophysical Properties and Electroluminescence

    Institute of Scientific and Technical Information of China (English)

    ZHENG Yan; YANG Bing; ZHANG Hai-quan; LU Ping; SHEN Fang-zhong; LIU Lin-lin; XU Hai; YANG Guang-di; MA Yu-guang

    2007-01-01

    A soluble poly(meta-phenylene) derivative with rigid twisted biphenyl unit was synthesized by the Yamamoto coupling reaction. The polymer is soluble in common organic solvents, and the number-average molecular weight is about 6500. The UV-Vis and quantum chemical calculation indicate that the different conformation segments named "conformers" exist in the polymer backbones; it was also further confirmed by the single crystal X-ray diffraction study of the dimeric model compound. The π-π* transition of biphenyl segments of twisted and planar conformations made the polymer exhibit a strong absorption around 256 nm and a weak absorption at about 300 nm. Furthermore,the polymer exhibits a strong UV photoluminescence at 372 nm when the excitation wavelengths are longer than 300 nm. The ultraviolet-emitting electroluminescence(EL) device with the single layer structure shows EL λmax of the derivative at 370 nm.

  3. Team cohesion in intensive care nursing: at the interface of nurse self-concept and unit structure

    DEFF Research Database (Denmark)

    Paunova, Minna; Li-Ying, Jason

    2017-01-01

    Team cohesion is a critical factor in the provision of high-quality care, yet its antecedents remain understudied, particularly in the context of some healthcare professional groups where structural and individual constraints coexist, and demand for high quality performance is prevailing....... In this study, we focus on the nursing group in intensive care units (ICU). Not researched, yet important for employee attitudes towards their workplaces and workgroups, is the interface between the characteristics of individual care providers and those of the teams and organizations in which they are employed...... their teams as cohesive. A multi-source and multi-level study of approximately 140 nurses employed in 20 ICUs across Denmark demonstrates the critical role of self-concept in easing and enhancing the constraints workplaces impose on team cohesion. Furthermore, the study confirms the positive relationship...

  4. Protein kinase A induces recruitment of active Na+,K+-ATPase units to the plasma membrane of rat proximal convoluted tubule cells

    Science.gov (United States)

    Carranza, Maria Luisa; Rousselot, Martine; Chibalin, Alexander V; Bertorello, Alejandro M; Favre, Hervé; Féraille, Eric

    1998-01-01

    The aim of this study was to investigate the mechanism of control of Na+,K+-ATPase activity by the cAMP-protein kinase A (PKA) pathway in rat proximal convoluted tubules. For this purpose, we studied the in vitro action of exogenous cAMP (10−3 M dibutyryl-cAMP (db-cAMP) or 8-bromo-cAMP) and endogenous cAMP (direct activation of adenylyl cyclases by 10−5 M forskolin) on Na+,K+-ATPase activity and membrane trafficking.PKA activation stimulated both the cation transport and hydrolytic activity of Na+,K+-ATPase by about 40 %. Transport activity stimulation was specific to the PKA signalling pathway since (1) db-cAMP stimulated the ouabain-sensitive 86Rb+ uptake in a time- and dose-dependent fashion; (2) this effect was abolished by addition of H-89 or Rp-cAMPS, two structurally different PKA inhibitors; and (3) this stimulation was not affected by inhibition of protein kinase C (PKC) by GF109203X. The stimulatory effect of db-cAMP on the hydrolytic activity of Na+,K+-ATPase was accounted for by an increased maximal ATPase rate (Vmax) without alteration of the efficiency of the pump, suggesting that cAMP-PKA pathway was implicated in membrane redistribution control.To test this hypothesis, we used two different approaches: (1) cell surface protein biotinylation and (2) subcellular fractionation. Both approaches confirmed that the cAMP-PKA pathway was implicated in membrane trafficking regulation. The stimulation of Na+,K+-ATPase activity by db-cAMP was associated with an increase (+40 %) in Na+,K+-ATPase units expressed at the cell surface which was assessed by Western blotting after streptavidin precipitation of biotinylated cell surface proteins. Subcellular fractionation confirmed the increased expression in pump units at the cell surface which was accompanied by a decrease (-30 %) in pump units located in the subcellular fraction corresponding to early endosomes.In conclusion, PKA stimulates Na+,K+-ATPase activity, at least in part, by increasing the number of

  5. Characterization of a CT unit for the detection of low contrast structures

    Science.gov (United States)

    Viry, Anais; Racine, Damien; Ba, Alexandre; Becce, Fabio; Bochud, François O.; Verdun, Francis R.

    2017-03-01

    Major technological advances in CT enable the acquisition of high quality images while minimizing patient exposure. The goal of this study was to objectively compare two generations of iterative reconstruction (IR) algorithms for the detection of low contrast structures. An abdominal phantom (QRM, Germany), containing 8, 6 and 5mm-diameter spheres (with a nominal contrast of 20HU) was scanned using our standard clinical noise index settings on a GE CT: "Discovery 750 HD". Two additional rings (2.5 and 5 cm) were also added to the phantom. Images were reconstructed using FBP, ASIR-50%, and VEO (full statistical Model Based Iterative Reconstruction, MBIR). The reconstructed slice thickness was 2.5 mm except 0.625 mm for VEO reconstructions. NPS was calculated to highlight the potential noise reduction of each IR algorithm. To assess LCD (low Contrast Detectability), a Channelized Hotelling Observer (CHO) with 10 DDoG channels was used with the area under the curve (AUC) as a figure of merit. Spheres contrast was also measured. ASIR-50% allowed a noise reduction by a factor two when compared to FBP without an improvement of the LCD. VEO allowed an additional noise reduction with a thinner slice thickness compared to ASIR-50% but with a major improvement of the LCD especially for the large-sized phantom and small lesions. Contrast decreased up to 10% with the phantom size increase for FBP and ASIR-50% and remained constant with VEO. VEO is particularly interesting for LCD when dealing with large patients and small lesion sizes and when the detection task is difficult.

  6. Structural determination of functional units of the nucleotide binding domain (NBD94 of the reticulocyte binding protein Py235 of Plasmodium yoelii.

    Directory of Open Access Journals (Sweden)

    Ardina Grüber

    Full Text Available BACKGROUND: Invasion of the red blood cells (RBC by the merozoite of malaria parasites involves a large number of receptor ligand interactions. The reticulocyte binding protein homologue family (RH plays an important role in erythrocyte recognition as well as virulence. Recently, it has been shown that members of RH in addition to receptor binding may also have a role as ATP/ADP sensor. A 94 kDa region named Nucleotide-Binding Domain 94 (NBD94 of Plasmodium yoelii YM, representative of the putative nucleotide binding region of RH, has been demonstrated to bind ATP and ADP selectively. Binding of ATP or ADP induced nucleotide-dependent structural changes in the C-terminal hinge-region of NBD94, and directly impacted on the RBC binding ability of RH. METHODOLOGY/PRINCIPAL FINDINGS: In order to find the smallest structural unit, able to bind nucleotides, and its coupling module, the hinge region, three truncated domains of NBD94 have been generated, termed NBD94(444-547, NBD94(566-663 and NBD94(674-793, respectively. Using fluorescence correlation spectroscopy NBD94(444-547 has been identified to form the smallest nucleotide binding segment, sensitive for ATP and ADP, which became inhibited by 4-Chloro-7-nitrobenzofurazan. The shape of NBD94(444-547 in solution was calculated from small-angle X-ray scattering data, revealing an elongated molecule, comprised of two globular domains, connected by a spiral segment of about 73.1 A in length. The high quality of the constructs, forming the hinge-region, NBD94(566-663 and NBD94(674-793 enabled to determine the first crystallographic and solution structure, respectively. The crystal structure of NBD94(566-663 consists of two helices with 97.8 A and 48.6 A in length, linked by a loop. By comparison, the low resolution structure of NBD94(674-793 in solution represents a chair-like shape with three architectural segments. CONCLUSIONS: These structures give the first insight into how nucleotide binding

  7. Compressor-expander units for mobile fuel cell systems; Verdichter und Expander fuer mobile Brennstoffzellensysteme

    Energy Technology Data Exchange (ETDEWEB)

    Lang, O. [FEV Motorentechnik GmbH, Aachen (Germany).; Pischinger, S.; Schoenfelder, C.; Steidten, T. [RWTH Aachen (DE). Lehrstuhl fuer Verbrennungskraftmaschinen (VKA)

    2004-08-01

    The air supply of hydrogen-powered fuel cell systems containing PEM fuel cells has a significant impact on their efficiency and mode of operation. Therefore, several mechanical compressors and expanders were examined at the RWTH Aachen. Simulations were then performed to determine the behaviour of the fuel cell system. This article discusses the findings of a project commissioned by the Forschungsvereinigung Verbrennungskraftmaschinen e.V. (FVV). (orig.)

  8. Q Fever Outbreak Among Travelers to Germany Who Received Live Cell Therapy--United States and Canada, 2014.

    Science.gov (United States)

    Robyn, Misha P; Newman, Alexandra P; Amato, Michael; Walawander, Mary; Kothe, Cynthia; Nerone, James D; Pomerantz, Cynthia; Behravesh, Casey Barton; Biggs, Holly M; Dahlgren, F Scott; Pieracci, Emily G; Whitfield, Yvonne; Sider, Doug; Ozaldin, Omar; Berger, Lisa; Buck, Peter A; Downing, Mark; Blog, Debra

    2015-10-02

    During September–November 2014, the New York State Department of Health (NYSDOH) was notified of five New York state residents who had tested seropositive for Coxiella burnetii, the causative agent of Q fever. All five patients had symptoms compatible with Q fever (e.g., fever, fatigue, chills, and headache) and a history of travel to Germany to receive a medical treatment called "live cell therapy" (sometimes called "fresh cell therapy") in May 2014. Live cell therapy is the practice of injecting processed cells from organs or fetuses of nonhuman animals (e.g., sheep) into human recipients. It is advertised to treat a variety of health conditions. This practice is unavailable in the United States; however, persons can travel to foreign locations to receive injections. Local health departments interviewed the patients, and NYSDOH notified CDC and posted a report on CDC’s Epidemic Information Exchange to solicit additional cases. Clinical and exposure information for each patient was reported to the Robert Koch Institute in Germany, which forwarded the information to local health authorities. A Canada resident who also received live cell therapy in May 2014 was diagnosed with Q fever in July 2014. Clinicians should be aware of health risks, such as Q fever and other zoonotic diseases, among patients with a history of receiving treatment with live cell therapy products.

  9. GANDivAWeb: A web server for detecting early folding units ("foldons" from protein 3D structures

    Directory of Open Access Journals (Sweden)

    Krishnan Arun

    2008-03-01

    Full Text Available Abstract Background It has long been known that small regions of proteins tend to fold independently and are then stabilized by interactions between these distinct subunits or modules. Such units, also known as autonomous folding units (AFUs or"foldons" play a key role in protein folding. A knowledge of such early folding units has diverse applications in protein engineering as well as in developing an understanding of the protein folding process. Such AFUs can also be used as model systems in order to study the structural organization of proteins. Results In an earlier work, we had utilized a global network partitioning algorithm to identify modules in proteins. We had shown that these modules correlate well with AFUs. In this work, we have developed a webserver, GANDivAWeb, to identify early folding units or "foldons" in networks using the algorithm described earlier. The website has three functionalities: (a It is able to display information on the modularity of a database of 1420 proteins used in the original work, (b It can take as input an uploaded PDB file, identify the modules using the GANDivA algorithm and email the results back to the user and (c It can take as input an uploaded PDB file and a results file (obtained from functionality (b and display the results using the embedded viewer. The results include the module decomposition of the protein, plots of cartoon representations of the protein colored by module identity and connectivity as well as contour plots of the hydrophobicity and relative accessible surface area (RASA distributions. Conclusion We believe that the GANDivAWeb server, will be a useful tool for scientists interested in the phenomena of protein folding as well as in protein engineering. Our tool not only provides a knowledge of the AFUs through a natural graph partitioning approach but is also able to identify residues that are critical during folding. It is our intention to use this tool to study the topological

  10. Local Structure Analysis of Materials for Solar Cell Absorber Layer

    OpenAIRE

    Jewell, Leila Elizabeth

    2016-01-01

    This dissertation examines solar cell absorber materials that have the potential to replace silicon in solar cells, including several copper-based sulfides and perovskites. Earth-abundant absorbers such as these become even more cost-effective when used in a nanostructured solar cell. Atomic layer deposition (ALD) and chemical vapor deposition (CVD) deposit highly conformal films and hence are important tools for developing extremely thin absorber solar cells with scalability. Thus, the prima...

  11. Study on the coordination structure of pt sorbed on bacterial cells using x-ray absorption fine structure spectroscopy.

    Directory of Open Access Journals (Sweden)

    Kazuya Tanaka

    Full Text Available Biosorption has been intensively investigated as a promising technology for the recovery of precious metals from solution. However, the detailed mechanism responsible for the biosorption of Pt on a biomass is not fully understood because of a lack of spectroscopic studies. We applied X-ray absorption fine structure spectroscopy to elucidate the coordination structure of Pt sorbed on bacterial cells. We examined the sorption of Pt(II and Pt(IV species on bacterial cells of Bacillus subtilis and Shewanella putrefaciens in NaCl solutions. X-ray absorption near-edge structure and extended X-ray absorption fine structure (EXAFS of Pt-sorbed bacteria suggested that Pt(IV was reduced to Pt(II on the cell's surface, even in the absence of an organic material as an exogenous electron donor. EXAFS spectra demonstrated that Pt sorbed on bacterial cells has a fourfold coordination of chlorine ions, similar to PtCl42-, which indicated that sorption on the protonated amine groups of the bacterial cells. This work clearly demonstrated the coordination structure of Pt sorbed on bacterial cells. The findings of this study will contribute to the understanding of Pt biosorption on biomass, and facilitate the development of recovery methods for rare metals using biosorbent materials.

  12. Elicitation of T-cell responses by structural and non-structural proteins of coxsackievirus B4.

    Science.gov (United States)

    Bengs, Suvi; Marttila, Jane; Susi, Petri; Ilonen, Jorma

    2015-02-01

    Coxsackievirus B4 (CV-B4) belongs to the genus Enterovirus within the family Picornaviridae. To investigate target proteins recognized by T-cells in human enterovirus B infections, virus-encoded structural [VP0 (VP4 and VP2), VP1, VP3] and non-structural (2A, 2B, 2C, 3C and 3D) proteins were expressed and purified in Escherichia coli. Peripheral blood of 19 healthy adult donors was used to create enterovirus-specific T-cell lines by repeated stimulation with CV-B4 cell lysate antigen. T-cell lines responded in individual patterns, and responses to all purified proteins were observed. The most often recognized enteroviral protein was VP0, which is the fusion between the most conserved structural proteins, VP4 and VP2. T-cell responses to VP0 were detected in 15 of the 19 (79 %) donor lines. Non-structural 2C protein was recognized in 11 of the 19 (58 %) lines, and 11 of the 19 (58 %) lines also had a response to 3D protein. Furthermore, responses to other non-structural proteins (2A, 2B and 3C) were also detected. T-cell responses did not correlate clearly to the individual HLA-DR-DQ phenotype or the history of past coxsackie B virus infections of the donors.

  13. Cell descent caused by boundary curvature of a high topographical structure for a device that changes cell density

    Science.gov (United States)

    Okutani, Chihiro; Wagatsuma, Akira; Mabuchi, Kunihiko; Hoshino, Takayuki

    2017-06-01

    Noninvasive techniques of controlling cell migration on substrates are widely useful for tissue engineering. However, the cell migration controls of previous studies were not enough for collecting cells locally. To solve this problem, in this work, we report the C2C12 mouse myoblast cell migration difference (descend or be repelled) by changing the curvature of the boundary of a topographical structure when the cells move from a flat surface to the boundary. 69% of the cells coming across a round boundary — the curvature radius of which was 50 µm — descended into the hole. In contrast, no cells descended into a groove with a linear boundary. Moreover, we demonstrated the cell spatial density change from the difference at the boundary. This finding will provide a new device that will enable us to manipulate spatial cell density noninvasively for tissue engineering.

  14. Development of a unit suitable for corrosion monitoring in district heating systems. Experiences with the LOCOR-cell test method

    DEFF Research Database (Denmark)

    Andersen, Asbjørn; Hilbert, Lisbeth Rischel

    2004-01-01

    the purpose, background and gained results of one of the used monitoring techniques, the crevice corrosion measurements obtained by the LOCOR-Cell„§. The crevice corrosion cell was developed by FORCE Technology in a previous district heating project financed by Nordic Industrial Fund (1)(2). Results from...... in 6 pressurised circulating heating systems and in one cooling system. 7 different corrosion monitoring methods have been used to study corrosion rates and types in dependency of water chemistry. This paper describes the design of the by-pass unit including water analysis methods. It also describes...... other used corrosion monitoring methods in the project are described elsewhere (3) and (4). For future district heating corrosion monitoring the by-pass unit can be recommended for permanent installation and the two methods high sensitive ER-technique (Metricorr) and the LOCOR-Cell„§ (FORCE Technology...

  15. Development of a unit suitable for corrosion monitoring in district heating systems. Experiences with the LOCOR-cell test method

    DEFF Research Database (Denmark)

    Andersen, Asbjørn; Hilbert, Lisbeth Rischel

    2004-01-01

    the purpose, background and gained results of one of the used monitoring techniques, the crevice corrosion measurements obtained by the LOCOR-Cell„§. The crevice corrosion cell was developed by FORCE Technology in a previous district heating project financed by Nordic Industrial Fund (1)(2). Results from...... in 6 pressurised circulating heating systems and in one cooling system. 7 different corrosion monitoring methods have been used to study corrosion rates and types in dependency of water chemistry. This paper describes the design of the by-pass unit including water analysis methods. It also describes...... other used corrosion monitoring methods in the project are described elsewhere (3) and (4). For future district heating corrosion monitoring the by-pass unit can be recommended for permanent installation and the two methods high sensitive ER-technique (Metricorr) and the LOCOR-Cell„§ (FORCE Technology...

  16. Development of structured polymer electrolyte membranes for fuel cell applications

    Science.gov (United States)

    Gasa, Jeffrey

    The objective of this research was to explore structure-property relationships to develop the understanding needed for introduction of superior PEM materials. Polymer electrolyte membranes based on sulfonated poly(ether ketone ketone) (SPEKK) were fabricated using N-methyl pyrrolidone as casting solvent. The membranes were characterized in terms of properties that were relevant to fuel cell applications, such as proton conductivity, methanol permeability, and swelling properties, among others. It was found in this study that the proton conductivity of neat SPEKK membranes could reach the conductivity of commercial membranes such as NafionRTM. However, when the conductivity of SPEKK was comparable to NafionRTM, the swelling of SPEKK in water was quite excessive. The swelling problem was remedied by modifying the microstructure of SPEKK using different techniques. One of them involved blending of lightly sulfonated PEKK with highly acidic particles (sulfonated crosslinked polystyrene-SXLPS). Low sulfonation level of SPEKK was used to reduce the swelling of the membrane in water and the role of the highly acidic particles was to enhance the proton conductivity of the membrane. Because of the residual crystallinity in SPEKK with low sulfonation levels (IEC sulfone)) to act as mechanical reinforcement. It was found that miscibility behavior of the blends had a significant impact on the transport and swelling properties of these blends, which could be explained by the blend microstructure. The miscibility behavior was found to be strongly dependent on the sulfonation level of SPEKK. The conductivities of the blends were enhanced by as much as two orders of magnitude when the morphology was modified by electric field. The last approach was ionic crosslinking of the sulfonate groups in SPEKK using divalent cations, specifically barium ions. The crosslinking treatment has greatly improved the thermal stability of the membranes in both dry and wet conditions.

  17. Heterodimeric barnase-barstar vaccine molecules: influence of one versus two targeting units specific for antigen presenting cells.

    Directory of Open Access Journals (Sweden)

    Heidi Cecilie Larsen Spång

    Full Text Available It is known that targeting of antigen to antigen presenting cells (APC increases immune responses. However, it is unclear if more than one APC-specific targeting unit in the antigenic molecule will increase responses. To address this issue, we have here made heterodimeric vaccine molecules that each express four different fusion subunits. The bacterial ribonuclease barnase and its inhibitor barstar interact with high affinity, and the barnase-barstar complex was therefore used as a dimerization unit. Barnase and barstar were fused N-terminally with single chain fragment variable (scFvs targeting units specific for either MHC class II molecules on APC or the hapten 5-iodo-4-hydroxy-3-nitrophenylacetyl (NIP. C-terminal antigenic fusions were either the fluorescent protein mCherry or scFv(315 derived from myeloma protein M315. The heterodimeric vaccine molecules were formed both in vitro and in vivo. Moreover, the four different fused moieties appeared to fold correctly since they retained their specificity and function. DNA vaccination with MHC class II-targeted vaccine induced higher mCherry-specific IgG1 responses compared to non-targeted control. Since mCherry and MHC class II are in trans in this heterodimer, this suggests that heterodimeric proteins are formed in vivo without prior protein purification. Surprisingly, one targeting moiety was sufficient for the increased IgG1 response, and addition of a second targeting moiety did not increase responses. Similar results were found in in vitro T cell assays; vaccine molecules with one targeting unit were as potent as those with two. In combination with the easy cloning strategy, the heterodimeric barnase-barstar vaccine molecule could provide a flexible platform for development of novel DNA vaccines with increased potency.

  18. Unit-Specific Event-Based and Slot-Based Hybrid Model Framework with Hierarchical Structure for Short-Term Scheduling

    Directory of Open Access Journals (Sweden)

    Yue Wang

    2015-01-01

    Full Text Available Unit-specific event-based continuous-time model has inaccurate calculation problems in involving resource constraints, due to the heterogeneous locations of the event points for different units. In order to address this limitation, a continuous-time unit-specific event-based and slot-based hybrid model framework with hierarchical structure is proposed in this work. A unit-specific event-based model without utility constraints is formulated in upper layer, and a slot-based model is introduced in lower layer. In the hierarchical structure, the two layers jointly address the short-term production scheduling problem of batch plants under utility consideration. The key features of this work include the following: (a eliminating overstrict constraints on utility resources, (b solving multiple counting problems, and (c considering duration time of event points in calculating utility utilization level. The effectiveness and advantages of proposed model are illustrated through two benchmark examples from the literatures.

  19. Structural studies of enzyme-based microfluidic biofuel cells

    Science.gov (United States)

    Togo, Makoto; Takamura, Akimasa; Asai, Tatsuya; Kaji, Hirokazu; Nishizawa, Matsuhiko

    An enzyme-based glucose/O 2 biofuel cell was constructed within a microfluidic channel to study the influence of electrode configuration and fluidic channel height on cell performance. The cell was composed of a bilirubin oxidase (BOD)-adsorbed O 2 cathode and a glucose anode prepared by co-immobilization of glucose dehydrogenase (GDH), diaphorase (Dp) and VK 3-pendant poly- L-lysine. The consumption of O 2 at the upstream cathode protected the downstream anode from interfering O 2 molecules, and consequently improved the cell performance (maximum cell current) ca. 10% for the present cell. The cell performance was also affected by the channel height. The output current and power of a 0.1 mm-height cell was significantly less than those of a 1 mm-height cell because of the depletion of O 2, as determined by the shape of the E- I curve at the cathode. On the other hand, the volume density of current and power was several times higher for the narrower cell.

  20. Inter-relationships between single carbon units' metabolism and resting energy expenditure in weight-losing patients with small cell lung cancer. Effects of methionine supply and chemotherapy

    DEFF Research Database (Denmark)

    Sengeløv, H; Hansen, O P; Simonsen, L;

    1994-01-01

    The one-carbon unit metabolism was investigated in 8 weight-losing patients with small cell carcinoma of the lung (SCLC). At diagnosis, 6 of the 8 patients had elevated formiminoglutamic acid (FIGLU) excretion after a histidine load, suggesting a lack of one-carbon units. In accordance, a signifi...