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Sample records for resistant fibrous structures

  1. Modelling and analysing oriented fibrous structures

    International Nuclear Information System (INIS)

    Rantala, M; Lassas, M; Siltanen, S; Sampo, J; Takalo, J; Timonen, J

    2014-01-01

    A mathematical model for fibrous structures using a direction dependent scaling law is presented. The orientation of fibrous nets (e.g. paper) is analysed with a method based on the curvelet transform. The curvelet-based orientation analysis has been tested successfully on real data from paper samples: the major directions of fibrefibre orientation can apparently be recovered. Similar results are achieved in tests on data simulated by the new model, allowing a comparison with ground truth

  2. Fibrous Protein Structures: Hierarchy, History and Heroes.

    Science.gov (United States)

    Squire, John M; Parry, David A D

    2017-01-01

    During the 1930s and 1940s the technique of X-ray diffraction was applied widely by William Astbury and his colleagues to a number of naturally-occurring fibrous materials. On the basis of the diffraction patterns obtained, he observed that the structure of each of the fibres was dominated by one of a small number of different types of molecular conformation. One group of fibres, known as the k-m-e-f group of proteins (keratin - myosin - epidermin - fibrinogen), gave rise to diffraction characteristics that became known as the α-pattern. Others, such as those from a number of silks, gave rise to a different pattern - the β-pattern, while connective tissues yielded a third unique set of diffraction characteristics. At the time of Astbury's work, the structures of these materials were unknown, though the spacings of the main X-ray reflections gave an idea of the axial repeats and the lateral packing distances. In a breakthrough in the early 1950s, the basic structures of all of these fibrous proteins were determined. It was found that the long protein chains, composed of strings of amino acids, could be folded up in a systematic manner to generate a limited number of structures that were consistent with the X-ray data. The most important of these were known as the α-helix, the β-sheet, and the collagen triple helix. These studies provided information about the basic building blocks of all proteins, both fibrous and globular. They did not, however, provide detailed information about how these molecules packed together in three-dimensions to generate the fibres found in vivo. A number of possible packing arrangements were subsequently deduced from the X-ray diffraction and other data, but it is only in the last few years, through the continued improvements of electron microscopy, that the packing details within some fibrous proteins can now be seen directly. Here we outline briefly some of the milestones in fibrous protein structure determination, the role of the

  3. Progressive failure analysis of fibrous composite materials and structures

    Science.gov (United States)

    Bahei-El-din, Yehia A.

    1990-01-01

    A brief description is given of the modifications implemented in the PAFAC finite element program for the simulation of progressive failure in fibrous composite materials and structures. Details of the memory allocation, input data, and the new subroutines are given. Also, built-in failure criteria for homogeneous and fibrous composite materials are described.

  4. FIBROUS MONOLITH WEAR RESISTANT COMPONENTS FOR THE MINING INDUSTRY

    Energy Technology Data Exchange (ETDEWEB)

    Mark J. Rigali; Kenneth L. Knittel; Mike L. Fulcher

    2002-03-01

    During this reporting period, work continued on development of formulations using the materials identified as contenders for the fibrous monolith wear resistant components. The FM structures fabricated were: diamond/WC-Co, B{sub 4}C/WC-Co, TiB{sub 2}/WC-Co, WC-Co/Co, WC-Co/WC-Co. Results of our consolidation densification studies on these systems lead to the down-selection of WC-Co/WC-Co, WC-Co/Co and diamond/WC-Co for further development for mining applications including drill bit inserts, roof bit inserts, radial tools conical tools and wear plates (WC-Co based system only) for earth moving equipment. Prototype component fabrication focused on the fabrication of WC-Co/WC-Co FM conical tools, diamond/WC-Co coated drill bit insert prototypes. Fabrication of WC-Co/WC-Co FM insert prototypes for a grader blade is also underway. ACR plans to initiate field-testing of the drill bit insert prototypes and the grader blade insert this summer (2002). The first WC-Co/WC-Co FM conical tool prototypes were sent to Kennametal for evaluation towards the end of the current reporting period.

  5. FIBROUS MONOLITH WEAR RESISTANT COMPONENTS FOR THE MINING INDUSTRY

    Energy Technology Data Exchange (ETDEWEB)

    Mark J. Rigali

    2001-10-01

    Published mechanical and thermal properties data on a variety of materials was gathered, with focus on materials that have potential with respect to developing wear resistant and damage tolerant composite for mining industry applications. Preliminary core materials of interest include but are not limited to: Diamond, Tungsten Carbide and Cemented Tungsten Carbides, Carbides of Boron, Silicon, Titanium and Aluminum, Diboride of Titanium and Aluminum, Nitrides of Aluminum, Silicon, Titanium, and Boron, Aluminum Oxide, Tungsten, Titanium, Iron, Cobalt and Metal Alloys. Preliminary boundary materials of interest include but are not limited to: W metal, WC-Co, W-Co, WFeNi, and Mo metal and alloys. Several FM test coupons were fabricated with various compositions using the above listed materials. These coupons were consolidated to varying degrees by uniaxial hot pressing, then cut and ground to expose the FM cell structure. One promising system, WC-Co core and WFeNi boundary, was consolidated to 97% of theoretical density, and demonstrates excellent hardness. Data on standard mechanical tests was gathered, and tests will begin on the consolidated test coupons during the upcoming reporting period. The program statements of work for ACR Inc. and its subcontractors, as well as the final contract negotiations, were finalized during the current reporting period. The program start date was February 22nd, 2001. In addition to the current subcontractors, Kennametal Inc., a major manufacturer of cutting tools and wear resistant tooling for the mining industry, expressed considerable interest in ACR's Fibrous Monolith composites for both machine and mining applications. At the request of Kennametal, ARC Inc fabricated and delivered several Fibrous Monolith coupons and components for testing and evaluation in the mining and machine tool applications. Additional samples of Diamond/Tungsten Carbide-6%Cobalt Fibrous Monolith were fabricated and delivered for testing Kennametal

  6. Electrospun porous structure fibrous film with high oil adsorption capacity.

    Science.gov (United States)

    Wu, Jing; Wang, Nü; Wang, Li; Dong, Hua; Zhao, Yong; Jiang, Lei

    2012-06-27

    A low-cost, high-oil-adsorption film consisting of polystyrene (PS) fibers is fabricated by a facile electrospinning method. Different fiber diameter and porous fiber's surface morphology play roles in oil adsorption capacity and oil/water selectivity. The results showed that oil adsorption capacity of PS oil sorbent film with small diameter and porous surface structure for diesel oil, silicon oil, peanut oil and motor oil were approximate to 7.13, 81.40, 112.30, and 131.63 g/g, respectively. It was higher than normal fibrous sorbent without any porous structure. The thinner porous PS oil sorbent also had excellent oil/water selectivity in the cleanup of oil from water.

  7. Structure-induced nonlinear viscoelasticity of non-woven fibrous matrices.

    Science.gov (United States)

    Rizvi, Mohd Suhail; Pal, Anupam; Das, Sovan Lal

    2016-12-01

    Fibrous materials are widely utilized as tissue engineering scaffolds for tissue regeneration and other bioengineering applications. The structural as well as mechanical characteristics of the fibrous matrices under static and dynamic mechanical loading conditions influence the response of the cells. In this paper, we study the mechanical response of the non-woven fibrous matrices under oscillatory loading conditions and its dependence on the structural properties of fibrous matrix. We demonstrate that under oscillatory shear and elongation, the fibrous matrices demonstrate nonlinear viscoelasticity at all strain amplitudes. This is contrary to the behavior of other soft polymeric materials for which nonlinearity in the viscoelastic response vanishes for small strains. These observations suggest that despite their prevalence, the measures of linear viscoelasticity (e.g., storage and loss moduli) are inadequate for the general description of the viscoelastic nature of the fibrous materials. It was, however, found that linear viscoelastic nature of fibrous matrices for small amplitudes is restored when a pre-stretch is applied to the fibrous matrix along with oscillatory strains. Further, we also explored the influence of the structural properties of the fibrous matrices (fiber orientation, alignment and curvature) on their viscoelastic nature.

  8. Different Structures of PVA Nano fibrous Membrane for Sound Absorption Application

    International Nuclear Information System (INIS)

    Mohrova, J.; Kalinova, K.

    2012-01-01

    The thin nano fibrous layer has different properties in the field of sound absorption in comparison with porous fibrous material which works on a principle of friction of air particles in contact with walls of pores. In case of the thin nano fibrous layer, which represents a sound absorber here, the energy of sonic waves is absorbed by the principle of membrane resonance. The structure of the membrane can play an important role in the process of converting the sonic energy to a different energy type. The vibration system acts differently depending on the presence of smooth fibers in the structure, amount of partly merged fibers, or structure of polymer foil as extreme. Polyvinyl alcohol (PVA) was used as a polymer because of its good water solubility. It is possible to influence the structure of nano fibrous layer during the production process thanks to this property of polyvinyl alcohol.

  9. Robust hydrophobic polyurethane fibrous membranes with tunable porous structure for waterproof and breathable application

    Science.gov (United States)

    Gu, Jiatai; Gu, Haihong; Cao, Jin; Chen, Shaojie; Li, Ni; Xiong, Jie

    2018-05-01

    In this work, novel nanofibrous membranes with waterproof and breathable (W&B) performance were successfully fabricated by the combination of electrospinning and surface modification technology. This fibrous membranes consisted of polyurethane (PU), NaCl, and fluoroalkylsilane (FAS). Firstly, The fibrous construction and porous structure of fibrous membranes were regulated by tuning the NaCl concentrations in PU solutions. Then, the obtained PU/NaCl fibrous membranes were further modified with fluoroalkylsilane (FAS) to improve hydrophobic property. The synergistic effect of porous structure and hydrophobicity on waterproof and breathable performance was investigated. Furthermore, the mechanical property of fibrous membranes was deeply analysed on the basis of macromolecule orientation and adhesive structure. Benefiting from the optimized porous structure and hydrophobic modification, the resultant fibrous membranes exhibited excellent waterproof (hydrostatic pressure of 1261 Mbar), breathable (water vapor transmission (WVT) rate of 9.06 kg m-2 d-1 and air permeability of 4.8 mm s-1) performance, as well as high tensile strength (breakage stress of 10.4 MPa), suggesting a promising candidate for various applications, especially in protective clothing.

  10. FIBROUS MONOLITH WEAR RESISTANT COMPONENTS FOR THE MINING INDUSTRY

    Energy Technology Data Exchange (ETDEWEB)

    Mike L. Fulcher; Kenneth L. Knittel

    2004-06-08

    The work performed on this program was to develop wear resistant, tough FM composite materials with efforts focused on WC-Co based FM systems. The materials were developed for use in mining industry wear applications. Components of interest were drill bit inserts for drilling blast holes. Other component applications investigated included wear plates for a variety of equipment such as pit shovels, wear surfaces for conveyors, milling media for ball milling operations, hydrocyclone cones, grader blades and dozer teeth. Cross-cutting technologies investigated included hot metal extrusion dies, drill bits for circuit board fabrication, cutting tools for cast iron and aluminum machining. An important part of the work was identification of the standard materials used in drilling applications. A materials trade study to determine those metals and ceramics used for mining applications provided guidance for the most important materials to be investigated. WC-Co and diamond combinations were shown to have the most desirable properties. Other considerations such as fabrication technique and the ability to consolidate shifted the focus away from diamond materials and toward WC-Co. Cooperating partners such as Kennametal and Kyocera assisted with supplies, evaluations of material systems, fabricated parts and suggestions for cross-cutting technology applications for FM architectures. Kennametal provided the raw materials (WC-Co and Al-TiCN powders) for the extent of the material evaluations. Kyocera shared their research into various FM systems and provided laboratory testing of fabricated materials. Field testing provided by partners Superior Rock Bit and Brady Mining and Construction provided insight into the performance of the fabricated materials under actual operational conditions. Additional field testing of cross-cutting technology, the extrusion of hot metals, at Extruded Metals showed the potential for additional market development.

  11. FIBROUS MONOLITH WEAR RESISTANT COMPONENTS FOR THE MINING INDUSTRY

    Energy Technology Data Exchange (ETDEWEB)

    Kenneth L. Knittel

    2005-05-09

    The work performed on this program was to develop wear resistant, tough FM composite materials with efforts focused on WC-Co based FM systems. The materials were developed for use in mining industry wear applications. Components of interest were drill bit inserts for drilling blast holes. Other component applications investigated included wear plates for a variety of equipment such as pit shovels, wear surfaces for conveyors, milling media for ball milling operations, hydrocyclone cones, grader blades and dozer teeth. Cross-cutting technologies investigated included hot metal extrusion dies, drill bits for circuit board fabrication, cutting tools for cast iron and aluminum machining. An important part of the work was identification of the standard materials used in drilling applications. A materials trade study to determine those metals and ceramics used for mining applications provided guidance for the most important materials to be investigated. WC-Co and diamond combinations were shown to have the most desirable properties. Other considerations such as fabrication technique and the ability to consolidate shifted the focus away from diamond materials and toward WC-Co. Cooperating partners such as Kennametal and Kyocera assisted with supplies, evaluations of material systems, fabricated parts and suggestions for cross-cutting technology applications for FM architectures. Kennametal provided the raw materials (WC-Co and Al-TiCN powders) for the extent of the material evaluations. Kyocera shared their research into various FM systems and provided laboratory testing of fabricated materials. Kyocera also continued research of the FM systems with the intention of developing commercial markets for a variety of applications. The continued development of FM technology by Kyocera is seen as a direct result of the cooperation established under this funding. Kyocera has a specific interest in the commercial development of the FM technology and have licensed it and have paid

  12. Tensor-based morphometry of fibrous structures with application to human brain white matter.

    Science.gov (United States)

    Zhang, Hui; Yushkevich, Paul A; Rueckert, Daniel; Gee, James C

    2009-01-01

    Tensor-based morphometry (TBM) is a powerful approach for examining shape changes in anatomy both across populations and in time. Our work extends the standard TBM for quantifying local volumetric changes to establish both rich and intuitive descriptors of shape changes in fibrous structures. It leverages the data from diffusion tensor imaging to determine local spatial configuration of fibrous structures and combines this information with spatial transformations derived from image registration to quantify fibrous structure-specific changes, such as local changes in fiber length and in thickness of fiber bundles. In this paper, we describe the theoretical framework of our approach in detail and illustrate its application to study brain white matter. Our results show that additional insights can be gained with the proposed analysis.

  13. Ninth DOD/NASA/FAA Conference on Fibrous Composites in Structural Design, volume 1

    Energy Technology Data Exchange (ETDEWEB)

    Soderquist, J.R.; Neri, L.M.; Bohon, H.L.

    1992-09-01

    This publication contains the proceedings of the Ninth DOD/NASA/FAA conference on Fibrous Composites in structural Design. Presentations were made in the following areas of composite structural design: perspectives in composites; design methodology; design applications; design criteria; supporting technology; damage tolerance; and manufacturing. Separate abstracts have been indexed into the database for articles from this report.

  14. Ninth DOD/NASA/FAA Conference on Fibrous Composites in Structural Design, volume 2

    Science.gov (United States)

    Soderquist, Joseph R. (Compiler); Neri, Lawrence M. (Compiler); Bohon, Herman L. (Compiler)

    1992-01-01

    This publication contains the proceedings of the Ninth DOD/NASA/FAA Conference on Fibrous Composites in Structural Design held at Lake Tahoe, Nevada, during 4-7 Nov. 1991. Presentations were made in the following areas of composite structural design: perspectives in composites, design methodology, design applications, design criteria, supporting technology, damage tolerance, and manufacturing.

  15. Ninth DOD/NASA/FAA Conference on Fibrous Composites in Structural Design, volume 1

    Science.gov (United States)

    Soderquist, Joseph R. (Compiler); Neri, Lawrence M. (Compiler); Bohon, Herman L. (Compiler)

    1992-01-01

    This publication contains the proceedings of the Ninth DOD/NASA/FAA conference on Fibrous Composites in structural Design. Presentations were made in the following areas of composite structural design: perspectives in composites; design methodology; design applications; design criteria; supporting technology; damage tolerance; and manufacturing.

  16. Ninth DOD/NASA/FAA Conference on Fibrous Composites in Structural Design, volume 3

    Science.gov (United States)

    Soderquist, Joseph R. (Compiler); Neri, Lawrence M. (Compiler); Bohon, Herman L. (Compiler)

    1992-01-01

    This publication contains the proceedings of the Ninth DOD/NASA/FAA Conference on Fibrous Composites in Structural Design held at Lake Tahoe, Nevada, during 4-7 Nov. 1991. Presentations were made in the following areas of composite structural design: perspectives in composites, design methodology, design applications, design criteria, supporting technology, damage tolerance, and manufacturing.

  17. Ninth DOD/NASA/FAA Conference on Fibrous Composites in Structural Design, volume 2

    Energy Technology Data Exchange (ETDEWEB)

    Soderquist, J.R.; Neri, L.M.; Bohon, H.L.

    1992-09-01

    This publication contains the proceedings of the Ninth DOD/NASA/FAA Conference on Fibrous Composites in Structural Design held at Lake Tahoe, Nevada, during 4-7 Nov. 1991. Presentations were made in the following areas of composite structural design: perspectives in composites, design methodology, design applications, design criteria, supporting technology, damage tolerance, and manufacturing.

  18. 3D multi-layered fibrous cellulose structure using an electrohydrodynamic process for tissue engineering.

    Science.gov (United States)

    Kim, Minseong; Kim, GeunHyung

    2015-11-01

    Micro/nanofibrous structures have been applied widely in various tissue-engineering applications because the topological structures are similar to the extracellular matrix (ECM), which encourages a high degree of cell adhesion and growth. However, it has been difficult to produce a three-dimensional (3D) fibrous structure using controllable macro-pores. Recently, cellulose has been considered a high-potential natural-origin biomaterial, but its use in 3D biomedical structures has been limited due to its narrow processing window. Here, we suggest a new 3D cellulose scaffold consisting of multi-layered struts made of submicron-sized entangled fibers that were fabricated using an electrohydrodynamic direct jet (EHDJ) process that is spin-printing. By optimizing processing conditions (electric field strength, cellulose feeding rate, and distance between nozzle and target), we can achieve a multi-layered cellulose structure consisting of the cylindrically entangled cellulose fibers. To compare the properties of the fabricated 3D cellulose structure, we used a PCL fibrous scaffold, which has a similar fibrous morphology and pore geometry, as a control. The physical and in vitro biocompatibilities of both fibrous scaffolds were assessed using human dermal fibroblasts, and the cellulose structure showed higher cell adhesion and metabolic activities compared with the control. These results suggest the EHDJ process to be an effective fabricating tool for tissue engineering and the cellulose scaffold has high potential as a tissue regenerative material. Copyright © 2015 Elsevier Inc. All rights reserved.

  19. Crystal networks in silk fibrous materials: from hierarchical structure to ultra performance.

    Science.gov (United States)

    Nguyen, Anh Tuan; Huang, Qiao-Ling; Yang, Zhen; Lin, Naibo; Xu, Gangqin; Liu, Xiang Yang

    2015-03-01

    This review provides a comprehensive survey of the structural characteristics of crystal networks of silk soft fibrous materials in correlation with the macroscopic properties/performance and the network formation mechanisms. The correlation between the hierarchical mesoscopic structures and the mechanical properties of silk soft fibrous materials including silk fibroin hydrogels and naturally spun silk fibers are addressed based on the hierarchical crystal network models. Namely, two types of hierarchical networks are identified: the weak nanofibril-nanofibril interaction case (i.e., silk fibroin hydrogels), and the strong nanofibril-nanofibril interaction case (i.e., silk fibers). The macroscopic properties, i.e., the rheological/mechanical properties, can be controlled in terms of tuning different levels of hierarchical network structures by ultrasonication-induced gelation, introducing the initial nucleation centers, etc. Such controls take effect by different mesoscale assembly pathways, which are found to occur via different routes of the nucleation and growth processes. Furthermore, the hierarchical network model of soft fibrous materials can be applied to explain the superior mechanical properties and the unique strain-hardening behaviors of spider silk fibers within the framework of hierarchical breaking mechanism. Obviously, a knowledge of crystal networks will allow the prediction of the performance and engineering strategy of silk fibrous materials in generals. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Ninth DOD/NASA/FAA Conference on Fibrous Composites in Structural Design, volume 3

    Energy Technology Data Exchange (ETDEWEB)

    Soderquist, J.R.; Neri, L.M.; Bohon, H.L.

    1992-09-01

    This publication contains the proceedings of the Ninth DOD/NASA/FAA Conference on Fibrous Composites in Structural Design held at Lake Tahoe, Nevada, during 4-7 Nov. 1991. Presentations were made in the following areas of composite structural design: perspectives in composites, design methodology, design applications, design criteria, supporting technology, damage tolerance, and manufacturing. Separate abstracts have been prepared for articles from this report.

  1. Effect of sea component dissolution on fibrous structure of islands-in-the-sea spunbond nonwovens

    Science.gov (United States)

    Suvari, F.; Ulcay, Y.; Pourdeyhimi, B.

    2017-10-01

    This work presents the preliminary results of our efforts that focused on the development of lightweight and more fibrous nonwoven. For this objective, nonwoven webs that contain bicomponent filaments with island-in-the-sea cross section was produced by spunbonding, which involves extruding of sea and island polymer melts through dies, cooling, and attenuating the bicomponent filaments by high velocity air streams. Nylon-6 and Polyethylene were chosen as the island and sea polymers, respectively. Bonding process was applied to web first to keep structural integrity after removing the sea polymer. The web was hydroentangled with high speed water jets prior to the dissolving process to obtain fiber entanglement. Xylene, which is one of the few chemical that can dissolve Polyethylene, was used for the dissolution of the sea component from the fibrous structure of the spunbond nonwoven. Removal of the sea polymer from spunbond nonwovens that contain bicomponent filaments with islands-in-the-sea cross section was achieved by the developed dissolution process. Weight, thickness, and area of the nonwoven samples changed after the dissolution. After removing the sea polymer, spunbond nonwoven contains only thin island fibers and also gets lighter. Lightweight and more fibrous nonwovens can be obtained with the method given in this study.

  2. A Facile Method to Fabricate Anisotropic Hydrogels with Perfectly Aligned Hierarchical Fibrous Structures.

    Science.gov (United States)

    Mredha, Md Tariful Islam; Guo, Yun Zhou; Nonoyama, Takayuki; Nakajima, Tasuku; Kurokawa, Takayuki; Gong, Jian Ping

    2018-03-01

    Natural structural materials (such as tendons and ligaments) are comprised of multiscale hierarchical architectures, with dimensions ranging from nano- to macroscale, which are difficult to mimic synthetically. Here a bioinspired, facile method to fabricate anisotropic hydrogels with perfectly aligned multiscale hierarchical fibrous structures similar to those of tendons and ligaments is reported. The method includes drying a diluted physical hydrogel in air by confining its length direction. During this process, sufficiently high tensile stress is built along the length direction to align the polymer chains and multiscale fibrous structures (from nano- to submicro- to microscale) are spontaneously formed in the bulk material, which are well-retained in the reswollen gel. The method is useful for relatively rigid polymers (such as alginate and cellulose), which are susceptible to mechanical signal. By controlling the drying with or without prestretching, the degree of alignment, size of superstructures, and the strength of supramolecular interactions can be tuned, which sensitively influence the strength and toughness of the hydrogels. The mechanical properties are comparable with those of natural ligaments. This study provides a general strategy for designing hydrogels with highly ordered hierarchical structures, which opens routes for the development of many functional biomimetic materials for biomedical applications. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Study on the Unsteady Creep of Composite Beams with an Irregular Laminar Fibrous Structure Made from Nonlinear Hereditary Materials

    Science.gov (United States)

    Yankovskii, A. P.

    2017-09-01

    The creep of homogenous and hybrid composite beams of an irregular laminar fibrous structure is investigated. The beams consist of thin walls and flanges (load-carrying layers). The walls may be reinforced longitudinally or crosswise in the plane, and the load-carrying layers are reinforced in the longitudinal direction. The mechanical behavior of phase materials is described by the Rabotnov nonlinear hereditary theory of creep taking into account their possible different resistance to tension and compression. On the basis of hypotheses of the Timoshenko theory, with using the method of time steps, a problem is formulated for the inelastic bending deformation of such beams with account of the weakened resistance of their walls to the transverse shear. It is shown that, at discrete instants of time, the mechanical behavior of such structures can formally be described by the governing relations for composite beams made of nonlinear elastic anisotropic materials with a known initial stress state. The method of successive iterations, similar to the method of variable parameters of elasticity, is used to linearize the boundary-value problem at each instant of time. The bending deformation is investigated for homogeneous and reinforced cantilever and simply supported beams in creep under the action of a uniformly distributed transverse load. The cross sections of the beams considered are I-shaped. It is found that the use of the classical theory for such beams leads to the prediction of indefensibly underestimated flexibility, especially in long-term loading. It is shown that, in beams with reinforced load-carrying layers, the creep mainly develops due to the shear strains of walls. It is found that, in short- and long-term loadings of composite beams, the reinforcement structures rational by the criterion of minimum flexibility are different.

  4. Iron doped fibrous-structured silica nanospheres as efficient catalyst for catalytic ozonation of sulfamethazine.

    Science.gov (United States)

    Bai, Zhiyong; Wang, Jianlong; Yang, Qi

    2018-04-01

    Sulfonamide antibiotics are ubiquitous pollutants in aquatic environments due to their large production and extensive application. In this paper, the iron doped fibrous-structured silica (KCC-1) nanospheres (Fe-KCC-1) was prepared, characterized, and applied as a catalyst for catalytic ozonation of sulfamethazine (SMT). The effects of ozone dosage, catalyst dosage, and initial concentration of SMT were examined. The experimental results showed that Fe-KCC-1 had large surface area (464.56 m2 g -1 ) and iron particles were well dispersed on the catalyst. The catalyst had high catalytic performance especially for the mineralization of SMT, with mineralization ratio of about 40% in a wide pH range. With addition of Fe-KCC-1, the ozone utilization increased nearly two times than single ozonation. The enhancement of SMT degradation was mainly due to the surface reaction, and the increased mineralization of SMT was due to radical mechanism. Fe-KCC-1 was an efficient catalyst for SMT degradation in catalytic ozonation system.

  5. The influence of fibrous elastomer structure and porosity on matrix organization.

    Directory of Open Access Journals (Sweden)

    Jamie L Ifkovits

    Full Text Available Fibrous scaffolds are finding wide use in the field of tissue engineering, as they can be designed to mimic many native tissue properties and structures (e.g., cardiac tissue, meniscus. The influence of fiber alignment and scaffold architecture on cellular interactions and matrix organization was the focus of this study. Three scaffolds were fabricated from the photocrosslinkable elastomer poly(glycerol sebacate (PGS, with changes in fiber alignment (non-aligned (NA versus aligned (AL and the introduction of a PEO sacrificial polymer population to the AL scaffold (composite (CO. PEO removal led to an increase in scaffold porosity and maintenance of scaffold anisotropy, as evident through visualization, mechanical testing, and mass loss studies. Hydrated scaffolds possessed moduli that ranged between ∼3-240 kPa, failing within the range of properties (<300 kPa appropriate for soft tissue engineering. CO scaffolds were completely degraded as early as 16 days, whereas NA and AL scaffolds had ∼90% mass loss after 21 days when monitored in vitro. Neonatal cardiomyocytes, used as a representative cell type, that were seeded onto the scaffolds maintained their viability and aligned along the surface of the AL and CO fibers. When implanted subcutaneously in rats, a model that is commonly used to investigate in vivo tissue responses to biomaterials, CO scaffolds were completely integrated at 2 weeks, whereas ∼13% and ∼16% of the NA and AL scaffolds, respectively remained acellular. However, all scaffolds were completely populated with cells at 4 weeks post-implantation. Polarized light microscopy was used to evaluate the collagen elaboration and orientation within the scaffold. An increase in the amount of collagen was observed for CO scaffolds and enhanced alignment of the nascent collagen was observed for AL and CO scaffolds compared to NA scaffolds. Thus, these results indicate that the scaffold architecture and porosity are important

  6. Investigation on the effect of employing nano-fibrous structure as a scattering layer in dye sensitized solar cells

    International Nuclear Information System (INIS)

    Rahimi, S.; Mohammadpour, R.; Iraji zad, A.

    2012-01-01

    TiO 2 nano fibers with different diameters have been fabricated through electro-spinning method and employed as a scattering layer in dye sensitized solar cell. The amount of scattering from nano-fibrous layers depends on their diameters; Because of various ability of light collection in fibers with different diameters, it can directly influence the solar cell performance. In this study, we have studied the optical and electrical properties of TiO 2 nano fibers and solar cells based on these structures have been fabricated and characterized. Finally, by optimizing the structure of scattering layer, maximum efficiency of 6.8 p ercent h as been achieved using fibers in range of 200-350 nm diameter.

  7. Dendritic silica nanomaterials (KCC-1) with fibrous pore structure possess high DNA adsorption capacity and effectively deliver genes in vitro.

    Science.gov (United States)

    Huang, Xiaoxi; Tao, Zhimin; Praskavich, John C; Goswami, Anandarup; Al-Sharab, Jafar F; Minko, Tamara; Polshettiwar, Vivek; Asefa, Tewodros

    2014-09-16

    The pore size and pore structure of nanoporous materials can affect the materials' physical properties, as well as potential applications in different areas, including catalysis, drug delivery, and biomolecular therapeutics. KCC-1, one of the newest members of silica nanomaterials, possesses fibrous, large pore, dendritic pore networks with wide pore entrances, large pore size distribution, spacious pore volume and large surface area--structural features that are conducive for adsorption and release of large guest molecules and biomacromolecules (e.g., proteins and DNAs). Here, we report the results of our comparative studies of adsorption of salmon DNA in a series of KCC-1-based nanomaterials that are functionalized with different organoamine groups on different parts of their surfaces (channel walls, external surfaces or both). For comparison the results of our studies of adsorption of salmon DNA in similarly functionalized, MCM-41 mesoporous silica nanomaterials with cylindrical pores, some of the most studied silica nanomaterials for drug/gene delivery, are also included. Our results indicate that, despite their relatively lower specific surface area, the KCC-1-based nanomaterials show high adsorption capacity for DNA than the corresponding MCM-41-based nanomaterials, most likely because of KCC-1's large pores, wide pore mouths, fibrous pore network, and thereby more accessible and amenable structure for DNA molecules to diffuse through. Conversely, the MCM-41-based nanomaterials adsorb much less DNA, presumably because their outer surfaces/cylindrical channel pore entrances can get blocked by the DNA molecules, making the inner parts of the materials inaccessible. Moreover, experiments involving fluorescent dye-tagged DNAs suggest that the amine-grafted KCC-1 materials are better suited for delivering the DNAs adsorbed on their surfaces into cellular environments than their MCM-41 counterparts. Finally, cellular toxicity tests show that the KCC-1-based

  8. The Staphylococcus aureus extracellular matrix protein (Emp) has a fibrous structure and binds to different extracellular matrices.

    Science.gov (United States)

    Geraci, Jennifer; Neubauer, Svetlana; Pöllath, Christine; Hansen, Uwe; Rizzo, Fabio; Krafft, Christoph; Westermann, Martin; Hussain, Muzaffar; Peters, Georg; Pletz, Mathias W; Löffler, Bettina; Makarewicz, Oliwia; Tuchscherr, Lorena

    2017-10-20

    The extracellular matrix protein Emp of Staphylococcus aureus is a secreted adhesin that mediates interactions between the bacterial surface and extracellular host structures. However, its structure and role in staphylococcal pathogenesis remain unknown. Using multidisciplinary approaches, including circular dichroism (CD) and Fourier transform infrared (FTIR) spectroscopy, transmission electron (TEM) and immunogold transmission electron microscopy, functional ELISA assays and in silico techniques, we characterized the Emp protein. We demonstrated that Emp and its truncated forms bind to suprastructures in human skin, cartilage or bone, among which binding activity seems to be higher for skin compounds. The binding domain is located in the C-terminal part of the protein. CD spectroscopy revealed high contents of β-sheets (39.58%) and natively disordered structures (41.2%), and TEM suggested a fibrous structure consisting of Emp polymers. The N-terminus seems to be essential for polymerization. Due to the uncommonly high histidine content, we suggest that Emp represents a novel type of histidine-rich protein sharing structural similarities to leucine-rich repeats proteins as predicted by the I-TASSER algorithm. These new findings suggest a role of Emp in infections of deeper tissue and open new possibilities for the development of novel therapeutic strategies.

  9. From single fiber to macro-level mechanics: A structural finite-element model for elastomeric fibrous biomaterials.

    Science.gov (United States)

    D'Amore, Antonio; Amoroso, Nicholas; Gottardi, Riccardo; Hobson, Christopher; Carruthers, Christopher; Watkins, Simon; Wagner, William R; Sacks, Michael S

    2014-11-01

    In the present work, we demonstrate that the mesoscopic in-plane mechanical behavior of membrane elastomeric scaffolds can be simulated by replication of actual quantified fibrous geometries. Elastomeric electrospun polyurethane (ES-PEUU) scaffolds, with and without particulate inclusions, were utilized. Simulations were developed from experimentally-derived fiber network geometries, based on a range of scaffold isotropic and anisotropic behaviors. These were chosen to evaluate the effects on macro-mechanics based on measurable geometric parameters such as fiber intersections, connectivity, orientation, and diameter. Simulations were conducted with only the fiber material model parameters adjusted to match the macro-level mechanical test data. Fiber model validation was performed at the microscopic level by individual fiber mechanical tests using AFM. Results demonstrated very good agreement to the experimental data, and revealed the formation of extended preferential fiber orientations spanning the entire model space. We speculate that these emergent structures may be responsible for the tissue-like macroscale behaviors observed in electrospun scaffolds. To conclude, the modeling approach has implications for (1) gaining insight on the intricate relationship between fabrication variables, structure, and mechanics to manufacture more functional devices/materials, (2) elucidating the effects of cell or particulate inclusions on global construct mechanics, and (3) fabricating better performing tissue surrogates that could recapitulate native tissue mechanics. Copyright © 2014 Elsevier Ltd. All rights reserved.

  10. Rationalization of specific structure formation in electrospinning process: Study on nano-fibrous PCL- and PLGA-based scaffolds.

    Science.gov (United States)

    Saeed, Mahdi; Mirzadeh, Hamid; Zandi, Mojgan; Irani, Shiva; Barzin, Jalal

    2015-12-01

    Formation of specific structures on poly-ɛ-caprolactone (PCL) and poly lactide-co-glycolide (PLGA) based electrospun mats is rationalized and the effect of interactive parameters; high voltage and flow rate on unique surface topography is evaluated. By increasing the collecting time in electrospinning process and enhancing fiber to fiber repulsion, surface characteristics of mats changes from nano- to micro-topography. In this study surface topography of the fabricated mats based on PCL and PLGA were assessed using AFM and SEM techniques to display the distinct phenomenon occurs on collected random fibers. In this research the rationale behind the formation of bump and flower like structures on fibrous mats was discussed. Because of great potential application of the fabricated substrates in the fields of medical purposes, cell-matrix interaction was evaluated and in vitro biological test with human dermal fibroblast and mouse L929 fibroblast cells was performed to study the cell responses to different roughness of nano-fibers collected at different time intervals. Our results show that after 7 days, cell proliferation is improved on PCL collected at 40 min in the case of human fibroblast cells and on PCL collected in 70 min in the case of L929 mouse fibroblast cells. © 2015 Wiley Periodicals, Inc.

  11. Eighth DOD/NASA/FAA Conference on Fibrous Composites in Structural Design, part 2

    Energy Technology Data Exchange (ETDEWEB)

    Starnes, J.H. Jr.; Bohon, H.L.; Garzon, S.B.

    1990-09-01

    Papers presented at the conference are compiled. The conference provided a forum for the scientific community to exchange composite structures design information and an opportunity to observe recent progress in composite structures design and technology. Part 2 contains papers related to the following subject areas: the application in design; methodology in design; and reliability in design.

  12. Eighth DOD/NASA/FAA Conference on Fibrous Composites in Structural Design, Part 2

    Science.gov (United States)

    Starnes, James H., Jr. (Compiler); Bohon, Herman L. (Compiler); Garzon, Sherry B. (Compiler)

    1990-01-01

    Papers presented at the conference are compiled. The conference provided a forum for the scientific community to exchange composite structures design information and an opportunity to observe recent progress in composite structures design and technology. Part 2 contains papers related to the following subject areas: the application in design; methodology in design; and reliability in design.

  13. Eighth DOD/NASA/FAA Conference on Fibrous Composites in Structural Design, part 1

    Science.gov (United States)

    Starnes, James H., Jr. (Compiler); Bohon, Herman L. (Compiler); Garzon, Sherry B. (Compiler)

    1990-01-01

    The status, problems, and requirements in the technical disciplines related to the design of composite structures are discussed. Papers are presented in the areas of applications in design; concepts in design; and methodology in design.

  14. Eighth DOD/NASA/FAA Conference on Fibrous Composites in Structural Design, part 1

    Energy Technology Data Exchange (ETDEWEB)

    Starnes, J.H. Jr.; Bohon, H.L.; Garzon, S.B.

    1990-09-01

    The status, problems, and requirements in the technical disciplines related to the design of composite structures are discussed. Papers are presented in the areas of applications in design; concepts in design; and methodology in design.

  15. Influence of Carbon Dioxide Bubble on Pore in Fibrous Structure of Direct Methanol Fuel Cell

    Science.gov (United States)

    Sugimura, Masahiko; Fujimoto, Kozo

    Direct methanol fuel cell (DMFC) is promising as new portable power source in various electronics devises. However, the performance of DMFC decreases by many problems which the factor of the structure and material effects each species concentration in the electrode catalyst layer. The anode reaction in DMFC products carbon dioxide, and CO2 bubbles generate in anode electrode. Diffusion layer in DMFC electrode is made carbon paper. The CO2 bubbles resulted in gas slugs blocking the pores in carbon paper. The CO2 bubble is affected by structure and surface characteristics in the diffusion layer. The behavior of bubble is analyzed some structure. We showed the relationship between bubble effect and contact angle of carbon fiber. And also, the model results indicate that the contact angle can improve the cell performance.

  16. Structural Behavior of Fibrous Reinforced Concrete Hollow Core One-Way Slabs Strengthening by C.F.R.P

    Directory of Open Access Journals (Sweden)

    وصيف مجيد

    2016-02-01

    Full Text Available A reinforced concrete hollow core one-way slab is one of the types of slabs used widely around the world in residential and industrial buildings to take advantage of them Economic and thermal insulation as well as to reduce the self-weight of the construction. The aim of the present study is to examine the structural behavior of the reinforced concrete hollow core one-way slabs reduce failure using the normal concrete and fibrous concrete and then strengthened using carbon fiber(CFRPThis study include molding of ( 6 specimens differ in terms of the voids volume (Vv , volumetric percentage of steel fibers (ا, and then strengthened by using fibers of carbon , with the aim of rehabilitation by fibers, carbon polymer (CFRP is to find out how efficient element structural when treated after the occurrence of the failure and the validity of its use in the event of a failure has occurred entirely or partly in the roof, and re- examined using the same method and conditions that were examined ceilings is affected through it, knowing that these ceilings have been addressed and strengthened in the same way , the results of the tests of the models that have been rehabilitated using carbon fiber (CFRP, compared with the same models before strengthening and examined reduce failure, increased very high susceptibility endurance extreme , with the increase ranging from (51.6% to (96.2%, as has been observed decrease in deflection value of models after strengthening by (CFRP.It is concluded through this study the possibility of using its concrete hollow core one-way slab as a roofing system for buildings also proved the highly efficient for this slab after rehabilitation using carbon fiber (CFRP.

  17. A Novel Hierarchical Structured Poly(lactic acid/Titania Fibrous Membrane with Excellent Antibacterial Activity and Air Filtration Performance

    Directory of Open Access Journals (Sweden)

    Zhe Wang

    2016-01-01

    Full Text Available Hybrid poly(lactic acid/titania (PLA/TiO2 fibrous membranes exhibiting excellent air filtration performance and good antibacterial activity were prepared via the electrospinning technique. By varying the composition of the precursor solutions and the relative humidity, the morphologies of PLA/TiO2 fibers, including the nanopores and nanometer-scale protrusions on the surface of the fibers, could be regulated. The distribution of nanopores and TiO2 nanoparticles on the surface of PLA/TiO2 fibers was investigated. Nitrogen adsorption-desorption analysis revealed that nanopores and nanometer-scale protrusions play an important role in improving the specific surface area and nanopore volume of the relevant PLA/TiO2 fibrous membrane. Filtration performance tests conducted by measuring the penetration of sodium chloride aerosol particles with a 260 nm mass median diameter indicated that fibers with a high surface roughness, large specific surface area, and large nanopore volume greatly improved the particle capture efficiency and facilitated the penetration of airflow. Furthermore, the introduction of TiO2 nanoparticles endows the relevant fibrous membrane with antibacterial properties. The as-prepared PLA/TiO2 fibrous membrane loaded with 1.75 wt% TiO2 nanoparticles formed at a relative humidity of 45% exhibited a high filtration efficiency (99.996% and a relatively low pressure drop (128.7 Pa, as well as a high antibacterial activity of 99.5%.

  18. Acoustical properties of highly porous fibrous materials

    Science.gov (United States)

    Lambert, R. F.

    1979-01-01

    Highly porous, fibrous bulk sound absorbing materials are studied with a view toward understanding their acoustical properties and performance in a wide variety of applications including liners of flow ducts. The basis and criteria for decoupling of acoustic waves in the pores of the frame and compressional waves in the frame structure are established. The equations of motion are recast in a form that elucidates the coupling mechanisms. The normal incidence surface impedance and absorption coefficient of two types of Kevlar 29 and an open celled foam material are studied. Experimental values and theoretical results are brought into agreement when the structure factor is selected to provide a fit to the experimental data. A parametric procedure for achieving that fit is established. Both a bulk material quality factor and a high frequency impedance level are required to characterize the real and imaginary part of the surface impedance and absorption coefficient. A derivation of the concepts of equivalent density and dynamic resistance is presented.

  19. Electrohydrodynamic jet process for pore-structure-controlled 3D fibrous architecture as a tissue regenerative material: fabrication and cellular activities.

    Science.gov (United States)

    Kim, Min Seong; Kim, GeunHyung

    2014-07-22

    In this study, we propose a new scaffold fabrication method, "direct electro-hydrodynamic jet process," using the initial jet of an electrospinning process and ethanol media as a target. The fabricated three-dimensional (3D) fibrous structure was configured with multilayered microsized struts consisting of randomly entangled micro/nanofibrous architecture, similar to that of native extracellular matrixes. The fabrication of the structure was highly dependent on various processing parameters, such as the surface tension of the target media, and the flow rate and weight fraction of the polymer solution. As a tissue regenerative material, the 3D fibrous scaffold was cultured with preosteoblasts to observe the initial cellular activities in comparison with a solid-freeform fabricated 3D scaffold sharing a similar structural geometry. The cell-culture results showed that the newly developed scaffold provided outstanding microcellular environmental conditions to the seeded cells (about 3.5-fold better initial cell attachment and 2.1-fold better cell proliferation).

  20. Effects of dietary supplementations with the fibrous root of Rhizoma Coptidis and its main alkaloids on non-specific immunity and disease resistance of common carp.

    Science.gov (United States)

    Zhou, Xia; Peng, Yaozong; Li, Ling; He, Kai; Huang, Tao; Mou, Shaoxia; Feng, Min; Han, Bing; Ye, Xiaoli; Li, Xuegang

    2016-05-01

    The effects of fibrous root of Rhizoma Coptidis (FRC) and its main alkaloids on non-specific immunity and disease resistance of common carp were investigated. The fish were randomly assigned to seven groups: normal control group (NC), groups treated with 12.5 g/kg FRC (FRC-L), 25 g/kg FRC (FRC-M), 50 g/kg FRC (FRC-H), 0.78 g/kg total alkaloids (TA), 0.78 g/kg berberine (BBR), and 0.78 g/kg coptisine (Cop), respectively. Results showed that the activities of myeloperoxidase, lysozyme and respiratory burst were significantly elevated after treated with FRC-M, FRC-H, TA, BBR and Cop, and the complement C3 level and phagocytic activity were significantly increased in FRC-M, TA and BBR treated groups compared with NC group. The real-time PCR analysis indicated that FRC, TA, BBR and Cop could up-regulate the mRNA expression of IL-1β, TNF-α, lysozyme-c and C3, but down-regulate that of IL-10 in the head kidney of common carp. Besides, FRC-M, FRC-H, TA, BBR and Cop significantly enhanced the survival rate of common carp infected with Aeromonas hydrophila, when compared to NC group. It was concluded that the FRC could enhance the non-specific immunity and disease resistance of common carp and the main alkaloids might contribute to these effects. Copyright © 2016 Elsevier B.V. All rights reserved.

  1. APPRAISAL OF ECONOMICAL EFFICIENCY OF APPLICATION OF FIBROUS LINING IN THERMAL GASPLASMA FURNACES AND FURNACES OF RESISTANCE OF MACHINE-BUILDING PRODUCTION

    Directory of Open Access Journals (Sweden)

    V. I. Timoshpolskij

    2011-01-01

    Full Text Available The carried out calculations showed that partial modernization of thermal furnaces of machine building production by means of replacement of chamotte by fibrous fettling is economically reasonable and has rather short period of payback.

  2. Aligned composite structures for mitigation of impact damage and resistance to wear in dynamic environments

    Science.gov (United States)

    Mulligan, Anthony C.; Rigali, Mark J.; Sutaria, Manish P.; Popovich, Dragan; Halloran, Joseph P.; Fulcher, Michael L.; Cook, Randy C.

    2009-04-14

    Fibrous monolith composites having architectures that provide increased flaw insensitivity, improved hardness, wear resistance and damage tolerance and methods of manufacture thereof are provided for use in dynamic environments to mitigate impact damage and increase wear resistance.

  3. FIBROUS VEINS AND THEIR STRUCTURAL INTERPRETATIONS IN THE PALEOCENE-EOCENE UNITS OF THE ÇAMARDI (NİGDE REGION

    Directory of Open Access Journals (Sweden)

    Yaşar EREN

    2008-02-01

    Full Text Available In the Çamardı region, the Nigde Massif consist of Palaeozoic-Mesozoic marble, gneiss, quartzite and amhibolite. The high-grade metamorphic rocks of massif are cut by the Cretaceous Üçkapılı granodiorite. These basement rocks were overlain by the cover rocks of Paleocene-Eocene age that display very low grade metamorphism. The Paleocene-Eocene cover units underwent at least three phases of deformation, as designated D1, D2- and D3 which D1- affected both the basement and cover, polyphase folding and low-grade metamorphism due to closing of the Ulukısla basin. The poly-phase deformation also resulted in the wide spread development extensional vein sets generally in mesoscopic scale. Most of the veins are filled with the fibrous minerals. The fibrous veins are mostly sintaxial, antitaxial and ataxial veins. The mineral fibres have curved shape indicating the rotational progressive deformations. Structural analysis of mineral fibres, shows that the maximum elongation direction (X- axis of deformation elipsoid has northeast-southwest trend, during the D1- event. With the other structural features, the tectonic transport of cover units most probaply developed from northeast to the southwest. Due to rotational progressive deformation during the D2- event, the maksimum elongation direction appears to rotate to north-northwest – south-southwest direction with an anticlockwise sense.

  4. Influence of porosity and pore shape on structural, mechanical and biological properties of poly ϵ-caprolactone electro-spun fibrous scaffolds.

    Science.gov (United States)

    Fuller, Kieran P; Gaspar, Diana; Delgado, Luis M; Pandit, Abhay; Zeugolis, Dimitrios I

    2016-05-01

    Electro-spun scaffolds are utilized in a diverse spectrum of clinical targets, with an ever-increasing quantity of work progressing to clinical studies and commercialization. The limited number of conformations in which the scaffolds can be fabricated hampers their wide acceptance in clinical practice. Herein, we assessed a single-strep fabrication process for predesigned electro-spun scaffold preparation and the ramifications of the introduction of porosity (0, 30, 50, 70%) and pore shape (circle, rhomboid, square) on structural, mechanical (tensile and ball burst) and biological (dermal fibroblast and THP-1) properties. The collector design did not affect the fibrous nature of the scaffold. Modulation of the porosity and pore shape offered control over the mechanical properties of the scaffolds. Neither the porosity nor the pore shape affected cellular (dermal fibroblast and THP-1) response. Overall, herein we provide evidence that electro-spun scaffolds of controlled architecture can be fabricated with fibrous fidelity, adequate mechanical properties and acceptable cytocompatibility for a diverse range of clinical targets.

  5. Fibrous dysplasia in paranasal cavities.

    Science.gov (United States)

    Simovic, S; Klapan, I; Bumber, Z; Bura, M

    1996-01-01

    Presentation is made of 2 boys and a girl with fibrous dysplasia involving the frontal and ethmoidal sinuses and the maxilla. This tumor-like growth of the bone was not restricted to the sinus alone but expanded to the orbit, adjacent sinus, skull base and infratemporal or pterygoid fossa. In such cases, surgical therapy is the treatment of choice, with maximal preservation of healthy tissue and avoidance of major devastations that may result in undesired cosmetic defects. The etiology of the disease is still unknown. However, it should be emphasized that all 3 patients had suffered an injury to the adjacent bony structures at various time points preceding the disease manifestation. That is why we are inclined to believe that trauma might be a factor responsible for the onset of fibrous dysplasia.

  6. Mathematical modeling of processes of devising fibrous composite materials and thin-walled structural elements by forced winding

    Science.gov (United States)

    Paimushin, V. N.; Sidorov, I. N.

    1990-05-01

    With the aid of the method of averaging processes in regular media, on the assumption that the temperature field in the semiproduct of PM is homogeneous at all stages of the production of thin-walled articles of CM, we suggested averaged equations of equilibrium, and also constructive algorithms for calculating the effective moduli and defining relations of the material of the semiproduct of CM. On the basis of these equations and the boundary conditions corresponding to them, we showed that it is possible to determine the RTS in a finished product of CM, and also to predict the change of its shape after removal from the mandrel and cutting it up into separate elements. To determine the above-mentioned technological characteristics of thin-walled elements made of fibrous CM, it is necessary to know the physicomechanical characteristics of the fibers and of the PM before and after polymerization; the volume fraction of the reinforcing filler and of the PM during winding, and also the orientation of the reinforcement; the relative change of volume of the PM after heat treatment and cooling; the prestresses in the fibers in the process of winding. It should be noted that the obtained averaged equations make it possible to calculate only the components of the averaged RTS in products of CM. To determine the local stresses in PM and fibers at all stages of making the product, it would be necessary to investigate in detail the rheology of PM at different temperatures.

  7. Fire resistance of structural composite lumber products

    Science.gov (United States)

    Robert H. White

    2006-01-01

    Use of structural composite lumber products is increasing. In applications requiring a fire resistance rating, calculation procedures are used to obtain the fire resistance rating of exposed structural wood products. A critical factor in the calculation procedures is char rate for ASTM E 119 fire exposure. In this study, we tested 14 structural composite lumber...

  8. Strength of Fibrous Composites

    CERN Document Server

    Huang, Zheng-Ming

    2012-01-01

    "Strength of Fibrous Composites" addresses evaluation of the strength of a fibrous composite by using its constituent material properties and its fiber architecture parameters. Having gone through the book, a reader is able to predict the progressive failure behavior and ultimate strength of a fibrous laminate subjected to an arbitrary load condition in terms of the constituent fiber and matrix properties, as well as fiber geometric parameters. The book is useful to researchers and engineers working on design and analysis for composite materials. Dr. Zheng-Ming Huang is a professor at the School of Aerospace Engineering & Applied Mechanics, Tongji University, China. Mr. Ye-Xin Zhou is a PhD candidate at the Department of Mechanical Engineering, the University of Hong Kong, China.

  9. Gastric Calcifying Fibrous Tumour

    Directory of Open Access Journals (Sweden)

    Tan Attila

    2006-01-01

    Full Text Available Intramucosal gastric tumours are most commonly found to be gastrointestinal stromal tumours or leiomyomas (smooth muscle tumours; however, a variety of other uncommon mesenchymal tumours can occur in the stomach wall. A rare benign calcifying fibrous tumour is reported and the endoscopic appearance, ultrasound findings and morphology are documented. A review of the literature found only two similar cases.

  10. Equivalent resistors of polyhedral resistive structures

    NARCIS (Netherlands)

    van Steenwijk, FJ

    The equivalent resistors of regular polyhedral resistive structures between any two of the vertices are calculated in terms of the characteristic properties of the structures. Some special cases are considered. (C) 1998 American Association of Physics Teachers.

  11. Composite fibrous glaucoma drainage implant

    Science.gov (United States)

    Klapstova, A.; Horakova, J.; Shynkarenko, A.; Lukas, D.

    2017-10-01

    Glaucoma is a frequent reason of loss vision. It is usually caused by increased intraocular pressure leading to damage of optic nerve head. This work deals with the development of fibrous structure suitable for glaucoma drainage implants (GDI). Commercially produced metallic glaucoma implants are very effective in lowering intraocular pressure. However, these implants may cause adverse events such as damage to adjacent tissue, fibrosis, hypotony or many others [1]. The aim of this study is to reduce undesirable properties of currently produced drains and improve their properties by creating of the composite fibrous drain for achieve a normal intraocular pressure. Two types of electrospinning technologies were used for the production of very small tubular implants. First type was focused for production of outer part of tubular drain and the second type of electrospinning method made the inner part of shape follows the connections of both parts. Complete implant had a special properties suitable for drainage of fluid. Morphological parameters, liquid transport tests and in-vitro cell adhesion tests were detected.

  12. Searching for Natural Conductive Fibrous Structures via a Green Sustainable Approach Based on Jute Fibers and Silver Nanoparticles

    Directory of Open Access Journals (Sweden)

    Diana P. Ferreira

    2018-01-01

    Full Text Available This paper provides new insights regarding jute fibers functionalization with silver nanoparticles (Ag NPs with improved conductivity values and highlights the sustainability of the processes involved. These NPs were applied onto jute fabrics by two different sustainable methods: ultraviolet (UV photoreduction and by using polyethylene glycol (PEG as a reducing agent and stabilizer. Field Emission Scanning Electron Microscopy (FESEM images demonstrated that the Ag NPs were incorporated on the jute fibers surface by the two different approaches, with sizes ranging from 70 to 100 nm. Diffuse reflectance spectra revealed the plasmon absorption band, corresponding to the formation of metallic Ag NPs, in all samples under study. Attenuated Total Reflectance-Fourier Transform Infrared Spectroscopy (ATR-FTIR was used to characterize the obtained samples, demonstrating NPs adsorption to the surface of the fibers. The resistivity value obtained by the two-point probe method of the jute fabric without functionalization is about 1.5 × 107 Ω·m, whereas, after NPs functionalization, it decreased almost 15,000 times, reaching a value of 1.0 × 103 Ω·m. Further research work is being undertaken for improving these values, however, 1000 Ω·m of resistivity (conductivity = 0.001 S/m is already a very reasonable value when compared with those obtained with other developed systems based on natural fibers. In summary, this work shows that the use of very simple methodologies enabled the functionalization of jute fibers with reasonable values of conductivity. This achievement has a huge potential for use in smart textile composites.

  13. Electrospun Fibrous Scaffolds for Tissue Engineering: Viewpoints on Architecture and Fabrication.

    Science.gov (United States)

    Jun, Indong; Han, Hyung-Seop; Edwards, James R; Jeon, Hojeong

    2018-03-06

    Electrospinning has been used for the fabrication of extracellular matrix (ECM)-mimicking fibrous scaffolds for several decades. Electrospun fibrous scaffolds provide nanoscale/microscale fibrous structures with interconnecting pores, resembling natural ECM in tissues, and showing a high potential to facilitate the formation of artificial functional tissues. In this review, we summarize the fundamental principles of electrospinning processes for generating complex fibrous scaffold geometries that are similar in structural complexity to the ECM of living tissues. Moreover, several approaches for the formation of three-dimensional fibrous scaffolds arranged in hierarchical structures for tissue engineering are also presented.

  14. Electrospun Fibrous Scaffolds for Tissue Engineering: Viewpoints on Architecture and Fabrication

    Directory of Open Access Journals (Sweden)

    Indong Jun

    2018-03-01

    Full Text Available Electrospinning has been used for the fabrication of extracellular matrix (ECM-mimicking fibrous scaffolds for several decades. Electrospun fibrous scaffolds provide nanoscale/microscale fibrous structures with interconnecting pores, resembling natural ECM in tissues, and showing a high potential to facilitate the formation of artificial functional tissues. In this review, we summarize the fundamental principles of electrospinning processes for generating complex fibrous scaffold geometries that are similar in structural complexity to the ECM of living tissues. Moreover, several approaches for the formation of three-dimensional fibrous scaffolds arranged in hierarchical structures for tissue engineering are also presented.

  15. Electrospun Fibrous Scaffolds for Tissue Engineering: Viewpoints on Architecture and Fabrication

    Science.gov (United States)

    Jun, Indong; Han, Hyung-Seop; Edwards, James R.; Jeon, Hojeong

    2018-01-01

    Electrospinning has been used for the fabrication of extracellular matrix (ECM)-mimicking fibrous scaffolds for several decades. Electrospun fibrous scaffolds provide nanoscale/microscale fibrous structures with interconnecting pores, resembling natural ECM in tissues, and showing a high potential to facilitate the formation of artificial functional tissues. In this review, we summarize the fundamental principles of electrospinning processes for generating complex fibrous scaffold geometries that are similar in structural complexity to the ECM of living tissues. Moreover, several approaches for the formation of three-dimensional fibrous scaffolds arranged in hierarchical structures for tissue engineering are also presented. PMID:29509688

  16. Electrical resistivity and structure of liquid Ge

    International Nuclear Information System (INIS)

    Can, P.; Armagan, T.

    2002-01-01

    The static structure factors are considered as an important ingredient in the calculation of the electrical resistivity of liquid metals. In this work, the electrical resistivity for liquid Germanium is interpreted with the Zeeman formalism in terms of pseudopotential and structure factor within the framework of the Hasagewa - Watabe (HW) for the interionic interactions. The successes and failures of the Zeeman formula have been compared with the available experimental data

  17. Earthquake resistant design of structures

    International Nuclear Information System (INIS)

    Choi, Chang Geun; Kim, Gyu Seok; Lee, Dong Geun

    1990-02-01

    This book tells of occurrence of earthquake and damage analysis of earthquake, equivalent static analysis method, application of equivalent static analysis method, dynamic analysis method like time history analysis by mode superposition method and direct integration method, design spectrum analysis considering an earthquake-resistant design in Korea. Such as analysis model and vibration mode, calculation of base shear, calculation of story seismic load and combine of analysis results.

  18. Effects of compression on the sound absorption of fibrous

    DEFF Research Database (Denmark)

    Castagnede, Bernard; Akninen, Achour; Brouard, Achour

    2000-01-01

    During the compression of a fibrous mat, it is well known that the absorption properties are decreasing. In order to predict this change, some heuristic formulae are proposed which take into account the modifications of the physical parameters(porosity, resistivity, tortousity and shappe factors)......) which enter in the standard "equivalent fluid" model. Numerical predictions are then discussed and compared to experimental data obtained on a fibrous material(uncompressed and the compressed) used in automotive industry....

  19. Electrospun nanocomposite fibrous polymer electrolyte for secondary lithium battery applications

    International Nuclear Information System (INIS)

    Padmaraj, O.; Rao, B. Nageswara; Jena, Paramananda; Satyanarayana, N.; Venkateswarlu, M.

    2014-01-01

    Hybrid nanocomposite [poly(vinylidene fluoride -co- hexafluoropropylene) (PVdF-co-HFP)/magnesium aluminate (MgAl 2 O 4 )] fibrous polymer membranes were prepared by electrospinning method. The prepared pure and nanocomposite fibrous polymer electrolyte membranes were soaked into the liquid electrolyte 1M LiPF 6 in EC: DEC (1:1,v/v). XRD and SEM are used to study the structural and morphological studies of nanocomposite electrospun fibrous polymer membranes. The nanocomposite fibrous polymer electrolyte membrane with 5 wt.% of MgAl 2 O 4 exhibits high ionic conductivity of 2.80 × 10 −3 S/cm at room temperature. The charge-discharge capacity of Li/LiCoO 2 coin cells composed of the newly prepared nanocomposite [(16 wt.%) PVdF-co-HFP+(5 wt.%) MgAl 2 O 4 ] fibrous polymer electrolyte membrane was also studied and compared with commercial Celgard separator

  20. Fibrous dysplasia and cherubism

    Directory of Open Access Journals (Sweden)

    Surajit Bhattacharya

    2015-01-01

    Full Text Available Fibrous dysplasia (FD is a non-malignant fibro-osseous bony lesion in which the involved bone/bones gradually get converted into expanding cystic and fibrous tissue. The underlying defect in FD is post-natal mutation of GNAS1 gene, which leads to the proliferation and activation of undifferentiated mesenchymal cells arresting the bone development in woven phase and ultimately converting them into fibro-osseous cystic tissue. Cherubism is a hereditary form of fibrous dysplasia in which the causative factor is transmission of autosomal dominant SH3BP2 gene mutation. The disease may present in two distinct forms, a less severe and limited monostotic form, and a more aggressive and more widespread polyostotic form. Polyostotic form may be associated with various endocrine abnormalities, which require active management apart from the management of FD. Management of FD is not free from controversies. While total surgical excision of the involved area and reconstruction using newer micro-vascular technique is the only definitive treatment available from the curative point of view, but this can be only offered to monostotic and very few polyostotic lesions. In polyostotic varieties on many occasions these radical surgeries are very deforming in these slow growing lesions and so their indication is highly debated. The treatment of cranio-facial fibrous dysplasia should be highly individualized, depending on the fact that the clinical behavior of lesion is variable at various ages and in individual patients. A more conservative approach in the form of aesthetic recontouring of deformed bone, orthodontic occlusal correction, and watchful expectancy may be the more accepted form of treatment in young patients. Newer generation real-time imaging guidance during recontouring surgery adds to accuracy and safety of these procedures. Regular clinical and radiological follow up is required to watch for quiescence, regression or reactivation of the disease process

  1. Fabrication of highly modulable fibrous 3D extracellular microenvironments

    KAUST Repository

    Zhang, Xixiang

    2017-06-13

    Three-dimensional (3D) in vitro scaffolds that mimic the irregular fibrous structures of in vivo extracellular matrix (ECM) are critical for many important biological applications. However, structural properties modulation of fibrous 3D scaffolds remains a challenge. Here, we report the first highly modulable 3D fibrous scaffolds self-assembled by high-aspect-ratio (HAR) microfibers. The scaffolds structural properties can be easily tailored to incorporate various physical cues, including geometry, stiffness, heterogeneity and nanotopography. Moreover, the fibrous scaffolds are readily and accurately patterned on desired locations of the substrate. Cell culture exhibits that our scaffolds can elicit strong bidirectional cell-material interactions. Furthermore, a functional disparity between the two-dimensional substrate and our 3D scaffolds is identified by cell spreading and proliferation data. These results prove the potential of the proposed scaffold as a biomimetic extracellular microenvironment for cell study.

  2. Structure effect on wear resistance of alloys

    International Nuclear Information System (INIS)

    Stepina, A.I.; Sidorova, L.I.; Tolstenko, E.V.

    1982-01-01

    The dependence of wear resistance on hardness of steels with different microstructure is studied under conditions of gas-abrasion wear of surface layers. It is found out that at the same hardness the wear resistance of α-alloys is higher than that of γ-alloys in spite of considerable surface hardening of austenitic alloys. Fracture of surface in the process of abrasive wear occurs after achievement of definite values of microhardness and the width of a diffraction line for each structural class of alloys [ru

  3. Fibrous dysplasia of maxillary sinus

    OpenAIRE

    Tinoco, Paulo; Pereira, José Carlos Oliveira; Lourenço Filho, Rodolfo Caldas; Silva, Fabrício Boechat do Carmo; Ruela, Karol Pereira

    2009-01-01

    Introduction: The Fibrous Dysplasia is a benign bone disease, of slow growth and unknown etiology. The involvement of the craniofacial skeleton is not uncommon and, generally, produces facial asymmetries. Case Report: In this article we report the case of a patient with fibrous dysplasia occupying the entire left maxillary sinus with orbitary extension confirmed in the anatomopathological exam. Final Comments: The surgical treatment remains as the main therapeutic approach and the postoperati...

  4. Palladium nanoparticles supported on fibrous-structured silica nanospheres (KCC-1): An efficient and selective catalyst for the transfer hydrogenation of alkenes

    KAUST Repository

    Qureshi, Ziyauddin

    2015-01-09

    An efficient palladium catalyst supported on fibrous silica nanospheres (KCC-1) has been developed for the hydrogenation of alkenes and α,β-unsaturated carbonyl compounds, providing excellent yields of the corresponding products with remarkable chemoselectivity. Comparison (high-resolution TEM, chemisorption) with analogous mesoporous (MCM-41, SBA-15) silica-supported Pd nanocatalysts prepared under identical conditions, demonstrates the advantage of employing the fibrous KCC-1 morphology versus traditional supports because it ensures superior accessibility of the catalytically active cores along with excellent Pd dispersion at high metal loading. This morphology ultimately leads to higher catalytic activity for the KCC-1-supported nanoparticles. The protocol developed for hydrogenation is advantageous and environmentally benign owing to the use of HCOOH as a source of hydrogen, water as a solvent, and because of efficient catalyst recyclability and durability. The recycled catalyst has been analyzed by XPS spectroscopy and TEM showing only minor changes in the oxidation state of Pd and in the morphology after the reaction, thus confirming the robustness of the catalyst.

  5. Fibrous dysplasia of maxillary sinus

    Directory of Open Access Journals (Sweden)

    Tinoco, Paulo

    2009-06-01

    Full Text Available Introduction: The Fibrous Dysplasia is a benign bone disease, of slow growth and unknown etiology. The involvement of the craniofacial skeleton is not uncommon and, generally, produces facial asymmetries. Case Report: In this article we report the case of a patient with fibrous dysplasia occupying the entire left maxillary sinus with orbitary extension confirmed in the anatomopathological exam. Final Comments: The surgical treatment remains as the main therapeutic approach and the postoperative follow-up is necessary due to this condition recurrent nature.

  6. Resistive field structures for semiconductor devices and uses therof

    Science.gov (United States)

    Marinella, Matthew; DasGupta, Sandeepan; Kaplar, Robert; Baca, Albert G.

    2017-09-12

    The present disclosure relates to resistive field structures that provide improved electric field profiles when used with a semiconductor device. In particular, the resistive field structures provide a uniform electric field profile, thereby enhancing breakdown voltage and improving reliability. In example, the structure is a field cage that is configured to be resistive, in which the potential changes significantly over the distance of the cage. In another example, the structure is a resistive field plate. Using these resistive field structures, the characteristics of the electric field profile can be independently modulated from the physical parameters of the semiconductor device. Additional methods and architectures are described herein.

  7. Computed tomographic features of fibrous dysplasia of maxillofacial region.

    Science.gov (United States)

    Sontakke, Subodh Arun; Karjodkar, Freny R; Umarji, Hemant R

    2011-03-01

    This study was to find the computed tomographic features of fibrous dysplasia of the maxillofacial region. All eight cases included in the study reported either to Government Dental College and Hospital or Nair Hospital Dental College, Mumbai between 2003 and 2009. The patients were prescribed computed tomogram in addition to conventional radiographs of maxillofacial region which were studied for characteristic features of fibrous dysplasia. The diagnosis of fibrous dysplasia was confirmed by histopathological report. All cases showed the ill-defined margins of lesions except in the region where the lesions were extending to cortex of the involved bone. Internal structure of all cases showed ground glass appearance. Four cases of maxillary lesion showed the displacement of maxillary sinus maintaining the shape of maxillary sinus. Two cases showed complete obliteration of maxillary sinus. Displacement of inferior alveolar canal did not follow any typical pattern in any of the cases but was displaced in different directions. The craniofacial type of fibrous dysplasia is as common as fibrous dysplasia of jaw. The margins, extent, internal structure and effect on surrounding structure are well detected on computed tomographic images.

  8. Computed tomographic features of fibrous dysplasia of maxillofacial region

    International Nuclear Information System (INIS)

    Sontakke, Subodh Arun; Karjodka, Freny R; Umarji, Hemant R

    2011-01-01

    This study was to find the computed tomographic features of fibrous dysplasia of the maxillofacial region. All eight cases included in the study reported either to Government Dental College and Hospital or Nair Hospital Dental College, Mumbai between 2003 and 2009. The patients were prescribed computed tomogram in addition to conventional radiographs of maxillofacial region which were studied for characteristic features of fibrous dysplasia. The diagnosis of fibrous dysplasia was confirmed by histopathological report. All cases showed the ill-defined margins of lesions except in the region where the lesions were extending to cortex of the involved bone. Internal structure of all cases showed ground glass appearance. Four cases of maxillary lesion showed the displacement of maxillary sinus maintaining the shape of maxillary sinus. Two cases showed complete obliteration of maxillary sinus. Displacement of inferior alveolar canal did not follow any typical pattern in any of the cases but was displaced in different directions. The craniofacial type of fibrous dysplasia is as common as fibrous dysplasia of jaw. The margins, extent, internal structure and effect on surrounding structure are well detected on computed tomographic images.

  9. Computed tomographic features of fibrous dysplasia of maxillofacial region

    Energy Technology Data Exchange (ETDEWEB)

    Sontakke, Subodh Arun; Karjodka, Freny R [Nair Hospital Dental College, Mumba (India); Umarji, Hemant R [Government Dental College and Hospital, Mumbai (India)

    2011-03-15

    This study was to find the computed tomographic features of fibrous dysplasia of the maxillofacial region. All eight cases included in the study reported either to Government Dental College and Hospital or Nair Hospital Dental College, Mumbai between 2003 and 2009. The patients were prescribed computed tomogram in addition to conventional radiographs of maxillofacial region which were studied for characteristic features of fibrous dysplasia. The diagnosis of fibrous dysplasia was confirmed by histopathological report. All cases showed the ill-defined margins of lesions except in the region where the lesions were extending to cortex of the involved bone. Internal structure of all cases showed ground glass appearance. Four cases of maxillary lesion showed the displacement of maxillary sinus maintaining the shape of maxillary sinus. Two cases showed complete obliteration of maxillary sinus. Displacement of inferior alveolar canal did not follow any typical pattern in any of the cases but was displaced in different directions. The craniofacial type of fibrous dysplasia is as common as fibrous dysplasia of jaw. The margins, extent, internal structure and effect on surrounding structure are well detected on computed tomographic images.

  10. Fibrous composites comprising carbon nanotubes and silica

    Science.gov (United States)

    Peng, Huisheng [Shanghai, CN; Zhu, Yuntian Theodore [Cary, NC; Peterson, Dean E [Los Alamos, NM; Jia, Quanxi [Los Alamos, NM

    2011-10-11

    Fibrous composite comprising a plurality of carbon nanotubes; and a silica-containing moiety having one of the structures: (SiO).sub.3Si--(CH.sub.2).sub.n--NR.sub.1R.sub.2) or (SiO).sub.3Si--(CH.sub.2).sub.n--NCO; where n is from 1 to 6, and R.sub.1 and R.sub.2 are each independently H, CH.sub.3, or C.sub.2H.sub.5.

  11. A call to expand regulation to all carcinogenic fibrous minerals

    Science.gov (United States)

    Baumann, F.; Steele, I.; Ambrosi, J.; Carbone, M.

    2013-05-01

    The regulatory term "asbestos" groups only the six fibrous minerals that were commercially used among approximately 400. The carcinogenicity of these six regulated minerals has been largely demonstrated and is related to fiber structure, fiber length/diameter ratio, and bio-persistence. From a public perception, the generic term "asbestos" refers to the fibrous minerals that cause asbestosis, mesothelioma and other cancers. However, other non-regulated fibrous minerals are potentially as dangerous as the regulatory asbestos because they share similar physical and chemical properties, epidemiological studies have demonstrated their relationship with asbestos-related diseases, and both in vitro and in vivo experiments have established the toxicity of these minerals. For example, the non-regulated asbestiform winchite and richterite minerals that contaminated the vermiculite mined from Libby, Montana, (USA) were associated with mesothelioma, lung cancer and asbestosis observed among the area's residents and miners. Many other examples of non-regulated carcinogenic fibrous minerals include, but are not limited to, antigorite, arfvedsonite, balangeroite, carlosturanite, erionite, fluoro-edenite, hornblende, mordenite, palygorskite, and sepiolite. To propose a regulatory definition that would provide protection from all carcinogenic fibers, we have conducted an interdisciplinary literature review to compare the characteristics of "asbestos" and of non-regulated mineral fibers that relate to carcinogenicity. We specifically studied two non-regulated fibrous minerals that are associated with asbestos-related diseases: the serpentine antigorite and the zeolite erionite. Both examples underscore the problem of regulation based on commercial, rather than scientific principles: 1) the occurrence of fibrous antigorite in materials used to pave roads has been correlated with high mesothelioma rates in New Caledonia. Antigorite was also the cause of asbestosis in Poland, and in

  12. Fibrous histiocytoma of the trachea.

    Science.gov (United States)

    Sandstrom, R E; Proppe, K H; Trelstad, R L

    1978-09-01

    The light and electron microscopic features of a fibrous histiocytoma of the trachea that occurred in a 15-year-old Caucasian girl are presented. Emphasis is placed on the aggresive behavior and the importance of early recognition of the lesion in an unusual location.

  13. Insights into the Effect of Structural Heterogeneity in Carbonized Electrospun Fibrous Mats for Flow Battery Electrodes by X-Ray Tomography.

    Science.gov (United States)

    Kok, Matt D R; Jervis, Rhodri; Brett, Dan; Shearing, Paul R; Gostick, Jeff T

    2018-03-01

    Electrospun custom made flow battery electrodes are imaged in 3D using X-ray computed tomography. A variety of computational methods and simulations are applied to the images to determine properties including the porosity, fiber size, and pore size distributions as well as the material permeability and flow distributions. The simulations are performed on materials before and after carbonization to determine the effect it has in the internal microstructure and material properties. It is found that the deposited fiber size is constantly changing throughout the electrospinning process. The results also show that the surfaces of the fibrous material are the most severely altered during carbonization and that the rest of the material remained intact. Pressure driven flow is modeled using the lattice Boltzmann method and excellent agreement with experimental results is found. The simulations coupled with the material analysis also demonstrate the highly heterogeneous nature of the flow. Most of the flow is concentrated to regions with high porosity while regions with low porosity shield other pores and starve them of flow. The importance of imaging these materials in 3D is highlighted throughout. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Air void structure and frost resistance

    DEFF Research Database (Denmark)

    Hasholt, Marianne Tange

    2014-01-01

    This article compiles results from 4 independent laboratory studies. In each study, the same type of concrete is tested at least 10 times, the air void structure being the only variable. For each concrete mix both air void analysis of the hardened concrete and a salt frost scaling test are conduc......This article compiles results from 4 independent laboratory studies. In each study, the same type of concrete is tested at least 10 times, the air void structure being the only variable. For each concrete mix both air void analysis of the hardened concrete and a salt frost scaling test...... is proportional to the product of total air content and specific surface. In all 4 cases, the conclusion is concurrent that the parameter of total surface area of air voids performs equally well or better than the spacing factor when linking air void characteristics to frost resistance (salt frost scaling......). This observation is interesting as the parameter of total surface area of air voids normally is not included in air void analysis. The following reason for the finding is suggested: In the air voids conditions are favourable for ice nucleation. When a capillary pore is connected to an air void, ice formation...

  15. Creep of fibrous composite materials

    DEFF Research Database (Denmark)

    Lilholt, Hans

    1985-01-01

    Models are presented for the creep behaviour of fibrous composite materials with aligned fibres. The models comprise both cases where the fibres remain rigid in a creeping matrix and cases where the fibres are creeping in a creeping matrix. The treatment allows for several contributions to the cr......Models are presented for the creep behaviour of fibrous composite materials with aligned fibres. The models comprise both cases where the fibres remain rigid in a creeping matrix and cases where the fibres are creeping in a creeping matrix. The treatment allows for several contributions...... such as Ni + W-fibres, high temperature materials such as Ni + Ni3Al + Cr3C2-fibres, and medium temperature materials such as Al + SiC-fibres. For the first two systems reasonable consistency is found for the models and the experiments, while for the third system too many unquantified parameters exist...

  16. MRI of angiomatoid fibrous histiocytoma

    Energy Technology Data Exchange (ETDEWEB)

    Li, Chao-Shiang; Chen, Wei-Tsung; Chen, Ran-Chou; Tu, Hsing-Yang [Taipei Municipal Jen-Ai Hospital, Department of Radiology, Taipei (Taiwan); Chan, Wing P. [Taipei Medical University, Department of Radiology, School of Medicine, Taipei (Taiwan); Taipei Municipal Wan-Fang Hospital, Department of Radiology, Taipei (Taiwan); Chang, Chih-Peng [Taipei Municipal Jen-Ai Hospital, Department of Orthopedic Surgery, Taipei (Taiwan); Shih, Li-Sun [Taipei Municipal Jen-Ai Hospital, Department of Pathology, Taipei (Taiwan)

    2004-10-01

    Angiomatoid fibrous histiocytoma is a rare soft tissue tumor of low-grade malignancy. We present the case of a 32-year-old man who complained of soreness and numbness over his left arm and hand over the previous 2 months and of having a palpable mass over his left upper back for 4 years. Magnetic resonance imaging (MRI) showed an intramuscular soft tissue mass in the left scapular region. The tumor mass was seen to have multiple cystic components with fluid-fluid levels. Histological examination showed multiple cystic spaces filled with blood lakes and hemosiderin deposits in the solid part of the tumor. After the initial surgery, the patient had local recurrences over 2.5 years. The immunohistochemical study at the second surgery showed that the recurrent tumor was strongly positive for the histiocytic marker CD68, and the myoid trait desmin. Histological diagnosis was compatible with angiomatoid fibrous histiocytoma. (orig.)

  17. Skeletal muscle ultrasound: correlation between fibrous tissue and echo intensity.

    NARCIS (Netherlands)

    Pillen, S.; Tak, R.O.; Zwarts, M.J.; Lammens, M.M.Y.; Verrijp, K.; Arts, I.M.P.; Laak, J.A.W.M. van der; Hoogerbrugge, P.M.; Engelen, B.G.M. van; Verrips, A.

    2009-01-01

    In this study, we examined the correlation between muscle ultrasound and muscle structure. Echo intensity (EI) of 14 muscles of two golden retriever muscular dystrophy dogs was correlated to the percentage interstitial fibrous tissue and fat in muscle biopsy. A significant correlation between

  18. HDPE/COC blends with fibrous morphology and their properties

    Czech Academy of Sciences Publication Activity Database

    Vacková, Taťana; Šlouf, Miroslav; Nevoralová, Martina; Kaprálková, Ludmila

    2012-01-01

    Roč. 48, č. 12 (2012), s. 2031-2039 ISSN 0014-3057 R&D Projects: GA ČR GP106/09/P272 Institutional research plan: CEZ:AV0Z40500505 Keywords : polymer blend * phase morphology * fibrous structure Subject RIV: JI - Composite Materials Impact factor: 2.562, year: 2012

  19. Horizontal gene transfer contributed to the evolution of extracellular surface structures: the freshwater polyp Hydra is covered by a complex fibrous cuticle containing glycosaminoglycans and proteins of the PPOD and SWT (sweet tooth families.

    Directory of Open Access Journals (Sweden)

    Angelika Böttger

    Full Text Available The single-cell layered ectoderm of the fresh water polyp Hydra fulfills the function of an epidermis by protecting the animals from the surrounding medium. Its outer surface is covered by a fibrous structure termed the cuticle layer, with similarity to the extracellular surface coats of mammalian epithelia. In this paper we have identified molecular components of the cuticle. We show that its outermost layer contains glycoproteins and glycosaminoglycans and we have identified chondroitin and chondroitin-6-sulfate chains. In a search for proteins that could be involved in organising this structure we found PPOD proteins and several members of a protein family containing only SWT (sweet tooth domains. Structural analyses indicate that PPODs consist of two tandem β-trefoil domains with similarity to carbohydrate-binding sites found in lectins. Experimental evidence confirmed that PPODs can bind sulfated glycans and are secreted into the cuticle layer from granules localized under the apical surface of the ectodermal epithelial cells. PPODs are taxon-specific proteins which appear to have entered the Hydra genome by horizontal gene transfer from bacteria. Their acquisition at the time Hydra evolved from a marine ancestor may have been critical for the transition to the freshwater environment.

  20. Horizontal gene transfer contributed to the evolution of extracellular surface structures: the freshwater polyp Hydra is covered by a complex fibrous cuticle containing glycosaminoglycans and proteins of the PPOD and SWT (sweet tooth) families.

    Science.gov (United States)

    Böttger, Angelika; Doxey, Andrew C; Hess, Michael W; Pfaller, Kristian; Salvenmoser, Willi; Deutzmann, Rainer; Geissner, Andreas; Pauly, Barbara; Altstätter, Johannes; Münder, Sandra; Heim, Astrid; Gabius, Hans-Joachim; McConkey, Brendan J; David, Charles N

    2012-01-01

    The single-cell layered ectoderm of the fresh water polyp Hydra fulfills the function of an epidermis by protecting the animals from the surrounding medium. Its outer surface is covered by a fibrous structure termed the cuticle layer, with similarity to the extracellular surface coats of mammalian epithelia. In this paper we have identified molecular components of the cuticle. We show that its outermost layer contains glycoproteins and glycosaminoglycans and we have identified chondroitin and chondroitin-6-sulfate chains. In a search for proteins that could be involved in organising this structure we found PPOD proteins and several members of a protein family containing only SWT (sweet tooth) domains. Structural analyses indicate that PPODs consist of two tandem β-trefoil domains with similarity to carbohydrate-binding sites found in lectins. Experimental evidence confirmed that PPODs can bind sulfated glycans and are secreted into the cuticle layer from granules localized under the apical surface of the ectodermal epithelial cells. PPODs are taxon-specific proteins which appear to have entered the Hydra genome by horizontal gene transfer from bacteria. Their acquisition at the time Hydra evolved from a marine ancestor may have been critical for the transition to the freshwater environment.

  1. Impregnated Fibrous Materials. Report of a Study Group on Impregnated Fibrous Materials

    International Nuclear Information System (INIS)

    1968-01-01

    There has recently been renewed interest in the use of radiation from radioisotopes or particle accelerators to initiate and sustain chemical reactions. Particular attention is being paid to the production of wood-plastic composites, a process which is now a commercial reality with radiation competing against chemical methods to enhance the properties of wood. It has been reported that water repellancy, hardness, weathering, insect and chemical resistance, compressive, bending and shear strength can be significantly improved by the process, but so far there has been a limited commercial outlet for the product. Papers on this subject were presented at the International Atomic Energy Agency's Symposium on Industrial Uses of Large Radiation Sources, Salzburg, May 1963, and since then the Agency has been aware of the interest of developing countries in conducting research on wood and other fibrous materials as a means of further exploiting natural resources. It was felt that some attempt should be made to co-ordinate, on a regional basis, the work being done in this field and at the same time review the world status, including the associated technology in such areas as monomer-polymer chemistry and impregnation techniques where they are directly related to this work. Because of the wide range of fibrous materials being studied there, Asia and the Far East was chosen as the most representative area and 39 participants from 13 countries, and from international organizations, met in Bangkok from 20 to 24 November 1967 to assess the potential of impregnated fibrous materials. This report is a record of the meeting and is based not only on work performed both inside and outside the region but also on details of the resources and industries in the area

  2. Fibrous dysplasia of the ethmoid sinus.

    Science.gov (United States)

    Tsai, Tung-Lung; Ho, Ching-Yin; Guo, Yuan-Ching; Chen, Winby; Lin, Ching-Zong

    2003-02-01

    Although craniofacial bone is the second common site of fibrous dysplasia involvement, it is rarely found in the paranasal sinus. Among fibrous dysplasia of the head and neck, the maxilla and mandible are the most frequent sites to be involved. Fibrous dysplasia becomes dormant in adolescence and early adult life and is more common in female. It is one of the fibrous osseous lesions and should be differentiated from osteoma and ossifying fibroma. Radiographically, fibrous dysplasia showed "groundglass" bone appearance on CT scans with bone window. Histopathologically, it presents woven-type bone embedded in a cellular fibrous stroma without osteoblastic rimming. We presented a case of 25-year-old female with fibrous dysplasia in her right side ethmoid sinus. She visited to us with the chief complaint of right side headache since adolescence. The lesion was removed by endoscopic sinus surgery and pathology proved fibrous dysplasia. The patient was free of headache after operation. The advance of endoscopic sinus surgical technique, makes it an optimal method for the pathological diagnosis and treatment to avoid the cosmetic problems caused by external approach in limited paranasal sinus fibrous osseous lesions.

  3. Imaging of soft tissue malignant fibrous histiocytoma

    International Nuclear Information System (INIS)

    Jemni, H.; Bakir, D.; Ben Ahmed, S.; Kraiem, C.; Mrad Dali, K.; Tlili-Graiess, K.; Mnif, Z.; Jeddi, M.

    1996-01-01

    Malignant fibrous histiocytoma (MFH) is a rare and potentially highly malignant sarcoma. The authors report 6 cases of MFH in various sites : two in the chest wall, one in the pelvis, two in the gluteal zones and one on the scalp. Ultrasonography and computed tomography were the main imaging methods used in the assessment of the structure and extension of the tumor. A poor prognosis was noted in four cases: death within a few months in the two thoracic sites, recurrence in the pelvic and scalp lesions, radical surgery allowed recovery in two cases. A review of the literature showed that MRI and CT are complementary in the initial staging and follow-up these patients. (author)

  4. Heat resistant/radiation resistant cable and incore structure test device for FBR type reactor

    International Nuclear Information System (INIS)

    Tanimoto, Hajime; Shiono, Takeo; Sato, Yoshimi; Ito, Kazumi; Sudo, Shigeaki; Saito, Shin-ichi; Mitsui, Hisayasu.

    1995-01-01

    A heat resistant/radiation resistant coaxial cable of the present invention comprises an insulation layer, an outer conductor and a protection cover in this order on an inner conductor, in which the insulation layer comprises thermoplastic polyimide. In the same manner, a heat resistant/radiation resistant power cable has an insulation layer comprising thermoplastic polyimide on a conductor, and is provided with a protection cover comprising braid of alamide fibers at the outer circumference of the insulation layer. An incore structure test device for an FBR type reactor comprises the heat resistant/radiation resistant coaxial cable and/or the power cable. The thermoplastic polyimide can be extrusion molded, and has excellent radiation resistant by the extrusion, as well as has high dielectric withstand voltage, good flexibility and electric characteristics at high temperature. The incore structure test device for the FBR type reactor of the present invention comprising such a cable has excellent reliability and durability. (T.M.)

  5. Novel two-step method to form silk fibroin fibrous hydrogel

    International Nuclear Information System (INIS)

    Ming, Jinfa; Li, Mengmeng; Han, Yuhui; Chen, Ying; Li, Han; Zuo, Baoqi; Pan, Fukui

    2016-01-01

    Hydrogels prepared by silk fibroin solution have been studied. However, mimicking the nanofibrous structures of extracellular matrix for fabricating biomaterials remains a challenge. Here, a novel two-step method was applied to prepare fibrous hydrogels using regenerated silk fibroin solution containing nanofibrils in a range of tens to hundreds of nanometers. When the gelation process of silk solution occurred, it showed a top-down type gel within 30 min. After gelation, silk fibroin fibrous hydrogels exhibited nanofiber network morphology with β-sheet structure. Moreover, the compressive stress and modulus of fibrous hydrogels were 31.9 ± 2.6 and 2.8 ± 0.8 kPa, respectively, which was formed using 2.0 wt.% concentration solutions. In addition, fibrous hydrogels supported BMSCs attachment and proliferation over 12 days. This study provides important insight in the in vitro processing of silk fibroin into useful new materials. - Highlights: • SF fibrous hydrogel was prepared by a novel two-step method. • SF solution containing nanofibrils in a range of tens to hundreds of nanometers was prepared. • Gelation process was top-down type gel with several minutes. • SF fibrous hydrogels exhibited nanofiber network morphology with β-sheet structure. • Fibrous hydrogels had higher compressive stresses superior to porous hydrogels.

  6. Frost resistance of fibre reinforced concrete structures

    DEFF Research Database (Denmark)

    Hansen, Ernst Jan De Place

    1999-01-01

    Frost resistance of fibre reinforced concrete with 2.5-4.2% air and 6-9% air (% by volume in fresh concrete) casted in the laboratory and in-situ is compared. Steel fibres with hooked ends (ZP, length 30 mm) and polypropylene fibres (PP, CS, length 12 mm) are applied. It is shown that· addition...... of 0.4-1% by volume of fibres cannot replace air entrainment in order to secure a frost resistant concrete; the minimum amount of air needed to make the concrete frost resistant is not changed when adding fibres· the amount of air entrainment must be increased when fibres are added to establish...

  7. Frost resistance of fibre reinforced concrete structures

    DEFF Research Database (Denmark)

    Hansen, Ernst Jan De Place

    1999-01-01

    of 0.4-1% by volume of fibres cannot replace air entrainment in order to secure a frost resistant concrete; the minimum amount of air needed to make the concrete frost resistant is not changed when adding fibres· the amount of air entrainment must be increased when fibres are added to establish......Frost resistance of fibre reinforced concrete with 2.5-4.2% air and 6-9% air (% by volume in fresh concrete) casted in the laboratory and in-situ is compared. Steel fibres with hooked ends (ZP, length 30 mm) and polypropylene fibres (PP, CS, length 12 mm) are applied. It is shown that· addition...

  8. Probability based high temperature engineering creep and structural fire resistance

    CERN Document Server

    Razdolsky, Leo

    2017-01-01

    This volume on structural fire resistance is for aerospace, structural, and fire prevention engineers; architects, and educators. It bridges the gap between prescriptive- and performance-based methods and simplifies very complex and comprehensive computer analyses to the point that the structural fire resistance and high temperature creep deformations will have a simple, approximate analytical expression that can be used in structural analysis and design. The book emphasizes methods of the theory of engineering creep (stress-strain diagrams) and mathematical operations quite distinct from those of solid mechanics absent high-temperature creep deformations, in particular the classical theory of elasticity and structural engineering. Dr. Razdolsky’s previous books focused on methods of computing the ultimate structural design load to the different fire scenarios. The current work is devoted to the computing of the estimated ultimate resistance of the structure taking into account the effect of high temperatur...

  9. Structural resistance of cashew ( Anacardium occidentale ) against ...

    African Journals Online (AJOL)

    Using artificial inoculation, mildew infection was possible on young leaves, but infection did not occur on older leaves. Epicuticular wax layer observed on cashew leaf surface, as a pre-infection resistance factor, appeared to be responsible for inhibition of germination and development of O. anacardii on older leaves.

  10. Effect of temperature on structure and corrosion resistance for ...

    Indian Academy of Sciences (India)

    Abstract. The effect of plating temperatures between 60 and 90◦C on structure and corrosion resistance for elec- troless NiWP coatings on AZ91D magnesium alloy substrate was investigated. Results show that temperature has a significant influence on the surface morphology and corrosion resistance of the NiWP alloy ...

  11. Effect of temperature on structure and corrosion resistance for ...

    Indian Academy of Sciences (India)

    The effect of plating temperatures between 60 and 90 ∘ C on structure and corrosion resistance for electroless NiWP coatings on AZ91D magnesium alloy substrate was investigated. Results show that temperature has a significant influence on the surface morphology and corrosion resistance of the NiWP alloy coating.

  12. Interaction of ruby laser with carbon fibrous materials

    Directory of Open Access Journals (Sweden)

    Stašić Jelena M.

    2007-01-01

    Full Text Available Carbon fibrous materials are interesting because of their good properties and numerous possible applications. The characteristics of these materials can be programmed by careful selection of the modification process parameters. The laser technique can be successfully employed for these purposes. The high temperatures arising in the material during a short laser pulse can cause a number of changes in the material. Carbon fibrous materials with different textile shapes, during different stages of processing, were exposed to laser radiation. A ruby laser (X=694.3 nm was used to modify the material. The structural changes were examined by scanning electron microscopy and X-ray diffraction. It was established that the radiation of this laser induces structural changes leading to a better arrangement of the turbostratic carbon fiber structure.

  13. Fibrous tissues growth and remodeling: Evolutionary micro-mechanical theory

    Science.gov (United States)

    Lanir, Yoram

    2017-10-01

    Living fibrous tissues are composite materials having the unique ability to adapt their size, shape, structure and mechanical properties in response to external loading. This adaptation, termed growth and remodeling (G&R), occurs throughout life and is achieved via cell-induced turnover of tissue constituents where some are degraded and new ones are produced. Realistic mathematical modeling of G&R provides insight into the basic processes, allows for hypotheses testing, and constitutes an essential tool for establishing clinical thresholds of pathological remodeling and for the production of tissue substitutes aimed to achieve target structure and properties. In this study, a general 3D micro-mechanical multi-scale theory of G&R in fibrous tissue was developed which connects between the evolution of the tissue structure and properties, and the underlying mechano-biological turnover events of its constituents. This structural approach circumvents a fundamental obstacle in modeling growth mechanics since the growth motion is not bijective. The model was realized for a flat tissue under two biaxial external loadings using data-based parameter values. The predictions show close similarity to characteristics of remodeled adult tissue including its structure, anisotropic and non-linear mechanical properties, and the onset of in situ pre-strain and pre-stress. The results suggest that these important features of living fibrous tissues evolve as they grow.

  14. Paget's disease and fibrous dysplasia.

    Science.gov (United States)

    Hullar, Timothy E; Lustig, Lawrence R

    2003-08-01

    Paget's disease and fibrous dysplasia are benign disorders that can involve the temporal bone and skull base. They commonly lead to otolaryngologic symptoms such as impingement of cranial nerves or the orbit or blockage of the external auditory canal or paranasal sinuses, although they can often be a challenge to diagnose because of their insidious presentation. Their benign nature and common presentation within the difficult-to-access confines of the skull base should lead the clinician to exercise caution in their treatment, reserving surgical intervention for either diagnosis or the relief of symptoms. As a better understanding of the etiology of these conditions develops and new pharmacotherapeutic agents are tested, it is likely that physicians will be able to turn to medical rather than surgical techniques to treat these disorders.

  15. Posttraumatic Cranial Cystic Fibrous Dysplasia

    Directory of Open Access Journals (Sweden)

    Arata Tomiyama

    2011-01-01

    Full Text Available A 14-year-old was girl admitted to our hospital with a subcutaneous mass of the occipital head. The mass had grown for 6 years, after she had sustained a head injury at the age of 6, and was located directly under a previous wound. Skull X-ray Photograph (xp, computed tomography (CT, and magnetic resonance imaging (MRI showed a bony defect and cystic changes in the skull corresponding to a subcutaneous mass. Bone scintigraphy revealed partial accumulation. The patient underwent total removal of the skull mass, and the diagnosis from the pathological findings of the cyst wall was fibrous dysplasia (FD. The radiographic findings for cystic cranial FD can be various. Progressive skull disease has been reported to be associated with head trauma, but the relationship between cranial FD and head trauma has not been previously reported. Previous studies have suggested that c-fos gene expression is a key mechanism in injury-induced FD.

  16. Nutritional fibrous osteodystrophy in goats

    Directory of Open Access Journals (Sweden)

    Paulo M Bandarra

    2011-10-01

    Full Text Available Seven out of 25 goats from a southern Brazilian flock developed nutritional fibrous osteodystrophy. Affected animals were younger than 1 year of age and were confined in stalls and fed a concentrate ration containing 1:6 calcium:phosphorus ratio. The remaining flock (35 goats was managed at pasture and showed no disease. Clinical signs were characterized by mandibular and maxillary enlargements, varying degrees of mouth opening and protruding tongue, dyspnea, apart of abnormalities of prehension and mastication. Affected animals had increased seric levels of phosphorus and parathormone, as well as higher alkaline phosphatase activity. Postmortem examination on three succumbed goats revealed bilateral enlargement of the maxilla and mandibula, and loose teeth, apart of multiple incomplete rib fractures in one of them. Severe diffuse proliferation of loose connective tissue surrounded the osteoid trabeculae, many of which were partially or completely non-mineralized. Mineralized osteoid trabeculae showed osteoclasts in the Howship's lacunae.

  17. Creep of fibrous composite materials

    DEFF Research Database (Denmark)

    Lilholt, Hans

    1985-01-01

    Models are presented for the creep behaviour of fibrous composite materials with aligned fibres. The models comprise both cases where the fibres remain rigid in a creeping matrix and cases where the fibres are creeping in a creeping matrix. The treatment allows for several contributions...... to the creep strength of composites. The advantage of combined analyses of several data sets is emphasized and illustrated for some experimental data. The analyses show that it is possible to derive creep equations for the (in situ) properties of the fibres. The experiments treated include model systems...... such as Ni + W-fibres, high temperature materials such as Ni + Ni3Al + Cr3C2-fibres, and medium temperature materials such as Al + SiC-fibres. For the first two systems reasonable consistency is found for the models and the experiments, while for the third system too many unquantified parameters exist...

  18. Structural Basis of Protein Oxidation Resistance: A Lysozyme Study

    OpenAIRE

    Girod, Marion; Enjalbert, Quentin; Brunet, Claire; Antoine, Rodolphe; Lemoine, Jérôme; Lukac, Iva; Radman, Miroslav; Krisko, Anita; Dugourd, Philippe

    2014-01-01

    Accumulation of oxidative damage in proteins correlates with aging since it can cause irreversible and progressive degeneration of almost all cellular functions. Apparently, native protein structures have evolved intrinsic resistance to oxidation since perfectly folded proteins are, by large most robust. Here we explore the structural basis of protein resistance to radiation-induced oxidation using chicken egg white lysozyme in the native and misfolded form. We study the differential resistan...

  19. Sustainable And Earthquake Resistant Structural Systems

    OpenAIRE

    Coşkun, Erdal; Kıymaz, Güven; Seçkin, Edip

    2010-01-01

    Sustainable design, which is one of the most important considerations in any structural design project nowadays, implies many factors such as environmental friendliness, energy competence, functionality, adaptability and efficient use of world's resources. Sustainable design is not only the realization of an architect's vision, but also the notion of the structural engineering regulation. As a result of close cooperation between architects and structural engineers, many brilliant and ele...

  20. Resistant Starch Regulates Gut Microbiota: Structure, Biochemistry and Cell Signalling.

    Science.gov (United States)

    Yang, Xiaoping; Darko, Kwame Oteng; Huang, Yanjun; He, Caimei; Yang, Huansheng; He, Shanping; Li, Jianzhong; Li, Jian; Hocher, Berthold; Yin, Yulong

    2017-01-01

    Starch is one of the most popular nutritional sources for both human and animals. Due to the variation of its nutritional traits and biochemical specificities, starch has been classified into rapidly digestible, slowly digestible and resistant starch. Resistant starch has its own unique chemical structure, and various forms of resistant starch are commercially available. It has been found being a multiple-functional regulator for treating metabolic dysfunction. Different functions of resistant starch such as modulation of the gut microbiota, gut peptides, circulating growth factors, circulating inflammatory mediators have been characterized by animal studies and clinical trials. In this mini-review, recent remarkable progress in resistant starch on gut microbiota, particularly the effect of structure, biochemistry and cell signaling on nutrition has been summarized, with highlights on its regulatory effect on gut microbiota. © 2017 The Author(s). Published by S. Karger AG, Basel.

  1. Fracture resistance enhancement of layered structures by multiple cracks

    DEFF Research Database (Denmark)

    Goutianos, Stergios; Sørensen, Bent F.

    2016-01-01

    A theoretical model is developed to test if the fracture resistance of a layered structure can be increased by introducing weak layers changing the cracking mechanism. An analytical model, based on the J integral, predicts a linear dependency between the number of cracks and the steady state...... fracture resistance. A finite element cohesive zone model, containing two cracking planes for simplicity, is used to check the theoretical model and its predictions. It is shown that for a wide range of cohesive law parameters, the numerical predictions agree well quantitatively with the theoretical model....... Thus, it is possible to enhance considerably the fracture resistance of a structure by adding weak layers....

  2. Linking microbial community structure and function to characterize antibiotic resistant bacteria and antibiotic resistant genes from cattle feces

    Science.gov (United States)

    There is widespread interest in monitoring the development of antibiotic resistant bacteria and antibiotic resistance genes in agriculturally impacted environments, however little is known about the relationships between bacterial community structure, and antibiotic resistance gene profiles. Cattl...

  3. Fibrous-Ceramic/Aerogel Composite Insulating Tiles

    Science.gov (United States)

    White, Susan M.; Rasky, Daniel J.

    2004-01-01

    Fibrous-ceramic/aerogel composite tiles have been invented to afford combinations of thermal-insulation and mechanical properties superior to those attainable by making tiles of fibrous ceramics alone or aerogels alone. These lightweight tiles can be tailored to a variety of applications that range from insulating cryogenic tanks to protecting spacecraft against re-entry heating. The advantages and disadvantages of fibrous ceramics and aerogels can be summarized as follows: Tiles made of ceramic fibers are known for mechanical strength, toughness, and machinability. Fibrous ceramic tiles are highly effective as thermal insulators in a vacuum. However, undesirably, the porosity of these materials makes them permeable by gases, so that in the presence of air or other gases, convection and gas-phase conduction contribute to the effective thermal conductivity of the tiles. Other disadvantages of the porosity and permeability of fibrous ceramic tiles arise because gases (e.g., water vapor or cryogenic gases) can condense in pores. This condensation contributes to weight, and in the case of cryogenic systems, the heat of condensation undesirably adds to the heat flowing to the objects that one seeks to keep cold. Moreover, there is a risk of explosion associated with vaporization of previously condensed gas upon reheating. Aerogels offer low permeability, low density, and low thermal conductivity, but are mechanically fragile. The basic idea of the present invention is to exploit the best features of fibrous ceramic tiles and aerogels. In a composite tile according to the invention, the fibrous ceramic serves as a matrix that mechanically supports the aerogel, while the aerogel serves as a low-conductivity, low-permeability filling that closes what would otherwise be the open pores of the fibrous ceramic. Because the aerogel eliminates or at least suppresses permeation by gas, gas-phase conduction, and convection, the thermal conductivity of such a composite even at

  4. Efficient and stable, structurally inverted poly(3-hexylthiopen): [6,6]-phenyl-C61-butyric acid methyl ester heterojunction solar cells with fibrous like poly(3-hexylthiopen)

    International Nuclear Information System (INIS)

    Bandara, Jayasundera; Shankar, Karthik; Grimes, Craig A.; Thelakkat, Mukundan

    2011-01-01

    We investigated an inverted organic photovoltaic device structure in which a densely packed ∼ 100 nm thin TiO 2 layer on fluorine doped conducting glass serves as anode and poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate)/Au layer on top of the active layer serves as cathode. The active layer is comprised of a blend of poly(3-hexylthiopene) (P3HT) and [6,6]-phenyl-C61-butyric acid methyl ester (PCBM). The rectification behavior of such a device is improved significantly and injection losses are minimized compared to devices without any compact TiO 2 layer. Moreover, nanostructured P3HT active layer was achieved in-situ by spin coating concentrated pure P3HT and P3HT:PCBM blend and solar cell performances on thickness of the active layer were also investigated. For the inverted solar cells constructed with different concentrations of P3HT and PCBM keeping the P3HT:PCBM ratio 1:0.8 (wt.%), the highest short circuit current and efficiency was observed when the P3HT and PCBM concentration was equal to 1.5 (wt.%) and 1.2 (wt.%) respectively. This leads to highly stable and reproducible power conversion efficiency above 3.7% at 100 mW/cm 2 light intensity under AM 1.5 conditions.

  5. Solitary Fibrous Tumor of the Uterus

    Directory of Open Access Journals (Sweden)

    Po-Wei Chu

    2006-12-01

    Conclusion: The behavior of solitary fibrous tumors arising from the uterus is difficult to evaluate; therefore, complete surgical excision featuring clear margins and comprehensive follow-up is recommended.

  6. Evaluation and histological maturation characteristics of fibrous ...

    African Journals Online (AJOL)

    osseous lesions (FOLS) that are generally considered to be separate entities distinguishable by histologic and radiographic features. The histological maturation of these lesions involves an initial fibrous state, an intermediate mixed and a final ...

  7. Isolated fibrous dysplasia of the sphenoid sinus.

    Science.gov (United States)

    Buyuklu, Fuat; Tarhan, Erkan; Cakmak, Ozcan; Ozgirgin, Nuri; Arikan, Unser

    2005-12-01

    Fibrous dysplasia is an uncommon benign bone disorder of unknown etiology in which normal medullary bone is replaced by fibrotic and osseous tissue. Solitary involvement of the sphenoid sinus is unusual. Here, we present the case of a 28-year-old man complaining of occipital and vertical headache. Imaging modalities demonstrated an expansile lesion filling the entire sphenoid sinus. Biopsy specimen was obtained by endoscopic sphenoidotomy. Diagnosis of fibrous dysplasia was made by imaging results and pathologic examination.

  8. Aggressive fibrous dysplasia of the maxillary sinus

    Energy Technology Data Exchange (ETDEWEB)

    Shapeero, L.G. (Dept. of Radiology, Inst. Gustave-Roussy, Villejuif (France) Dept. of Radiology, California Univ., San Francisco, CA (United States)); Vanel, D. (Dept. of Radiology, Inst. Gustave-Roussy, Villejuif (France)); Ackerman, L.V. (Dept. of Pathology, State Univ. of New York, Stony Brook, NY (United States)); Terrier-Lacombe, M.J. (Dept. of Radiology, Inst. Gustave-Roussy, Villejuif (France)); Housin, D. (Dept. of Radiology, Inst. Gustave-Roussy, Villejuif (France)); Schwaab, G. (Dept. of Ear, Nose, and Throat, Inst. Gustave-Roussy, Villejuif (France)); Sigal, R. (Dept. of Radiology, Inst. Gustave-Roussy, Villejuif (France)); Masselot, J. (Dept. of Radiology, Inst. Gustave-Roussy, Villejuif (France))

    1993-11-01

    Five of 34 patients (ages 4-21 years), who were subsequently diagnosed histologically as having fibrous dysplasia of the maxillary sinus, rapidly developed soft tissue masses of the malar region over a period of less than 4 months with accompanying pain (2 patients) and nasal obstruction and exophthalmos (2 patients). Each was clinically suspected of having a sarcoma. After resection, all lesions developed regrowth. At histopathologic examination, both initial and recurrent masses proved to be typical fibrous dysplasia. (orig./UWA)

  9. Isolated fibrous dysplasia of the ethmoid sinus

    OpenAIRE

    Yenigun, Alper; Akyuz, Servet

    2015-01-01

    Fibrous dysplasia is a benign fibro-osseous lesion progressing with one or more bone involvements in the skeleton. Even though it is a benign tumor, it may potentially transform into a malignant one. While the most frequently involved zones in the head–neck zone include the maxilla, mandible, parietal, occipital, and temporal zones, the involvement of the ethmoid bone is rather rare. This article presents the case of a female patient who was diagnosed with fibrous dysplasia in the right ethmo...

  10. Aggressive fibrous dysplasia of the maxillary sinus

    International Nuclear Information System (INIS)

    Shapeero, L.G.; Vanel, D.; Ackerman, L.V.; Terrier-Lacombe, M.J.; Housin, D.; Schwaab, G.; Sigal, R.; Masselot, J.

    1993-01-01

    Five of 34 patients (ages 4-21 years), who were subsequently diagnosed histologically as having fibrous dysplasia of the maxillary sinus, rapidly developed soft tissue masses of the malar region over a period of less than 4 months with accompanying pain (2 patients) and nasal obstruction and exophthalmos (2 patients). Each was clinically suspected of having a sarcoma. After resection, all lesions developed regrowth. At histopathologic examination, both initial and recurrent masses proved to be typical fibrous dysplasia. (orig./UWA)

  11. Fibrous incudostapedial joint in congenital aural atresia.

    Science.gov (United States)

    Balaker, Ashley E; Roberson, Joseph B; Goldsztein, Hernan

    2014-04-01

    (1) Determine the prevalence of a non-bony or fibrous incudostapedial (IS) joint in the setting of congenital aural atresia. (2) Assess this anomaly's impact on surgical management and associated hearing outcomes. Retrospective chart review. Subspecialty private practice. Operative reports and audiometric data of patients who underwent congenital aural atresia repair by a single surgeon from 2007 to 2011 were reviewed for operative anatomic findings and audiometric outcomes. Two hundred twenty-eight operations on 206 ears were performed. Median age was 5 years old. Fifty-five (26.7%) of these ears had a fibrous IS joint. The severity of this anomaly was graded as mild in 23 ears, moderate in 20 ears, and severe in 12 ears. Mean postoperative pure tone air conduction (PTA2) in the severely fibrous group was 51 compared to 46 in the moderate group (P = .03) and 41 in the mild group (P = .006). Patients with a fibrous IS joint who underwent successful ossicular chain reconstruction (OCR) had a mean postoperative PTA2 of 30, which was a significantly better outcome than in patients with moderately or severely fibrous IS joints who did not have OCR (P atresia. The severity of this anomaly has important implications for postoperative hearing results. These findings suggest that ossicular chain reconstruction should be performed in moderately or severely fibrous cases.

  12. Inferring the interaction structure of resistance to antimicrobials.

    Science.gov (United States)

    Zawack, Kelson; Love, Will; Lanzas, Cristina; Booth, James G; Gröhn, Yrjö T

    2018-04-01

    The growth of antimicrobial resistance presents a significant threat to human and animal health. Of particular concern is multi-drug resistance, as this increases the chances an infection will be untreatable by any antibiotic. In order to understand multi-drug resistance, it is essential to understand the association between drug resistances. Pairwise associations characterize the connectivity between resistances and are useful in making decisions about courses of treatment, or the design of drug cocktails. Higher-order associations, interactions, which tie together groups of drugs can suggest commonalities in resistance mechanism and lead to their identification. To capture interactions, we apply log-linear models of contingency tables to analyze publically available data on the resistance of Escheresia coli isolated from chicken and turkey meat by the National Antimicrobial Resistance Monitoring System. Standard large sample and conditional exact testing approaches for assessing significance of parameters in these models breakdown due to structured patterns inherent to antimicrobial resistance. To address this, we adopt a Bayesian approach which reveals that E. coli resistance associations can be broken into two subnetworks. The first subnetwork is characterized by a hierarchy of β-lactams which is consistent across the chicken and turkey datasets. Tier one in this hierarchy is a near equivalency between amoxicillin-clavulanic acid, ceftriaxone and cefoxitin. Susceptibility to tier one then implies susceptibility to ceftiofur. The second subnetwork is characterized by more complex interactions between a variety of drug classes that vary between the chicken and turkey datasets. Copyright © 2018 Elsevier B.V. All rights reserved.

  13. Giant solitary fibrous tumour of the liver

    Directory of Open Access Journals (Sweden)

    Eggermont Alexander MM

    2006-11-01

    Full Text Available Abstract Background Solitary fibrous tumour (SFT is an uncommon mesenchymal neoplasm that most frequently affects the pleura, although it has been reported with increasing frequency in various other sites such as in the peritoneum, pericardium and in non-serosal sites such as lung parenchyma, upper respiratory tract, orbit, thyroid, parotid gland, or thymus. Liver parenchyma is rarely affected. Clinically, SFTs cause symptoms after having reached a certain size or when vital structures are involved. In recent years, SFTs are more often identified and distinguished from other tumours with a similar appearance due to the availability of characteristic immunohistochemical markers. Case presentation In this manuscript we report the case of a large tumour of the liver, which was histologically diagnosed as a SFT, and showed involvement of a single hepatic segment. Because of the patient's presentation and clinical course, it may represent a radiation-induced lesion. Conclusion When a SFT has been diagnosed, surgery is the treatment of choice. The small number of patients with a SFT of the liver and its unknown natural behaviour creates the need to a careful registration and follow-up of all identified cases

  14. Essential Oil Bioactive Fibrous Membranes Prepared via Coaxial Electrospinning.

    Science.gov (United States)

    Yao, Zhi-Cheng; Chen, Si-Cong; Ahmad, Zeeshan; Huang, Jie; Chang, Ming-Wei; Li, Jing-Song

    2017-06-01

    A novel antimicrobial composite material was prepared by encapsulating orange essential oil (OEO) in zein prolamine (ZP) via the coaxial electrospinning (ES) technique. By manipulating process parameters, the morphological features of ZP/OEO fibers were modulated. Fine fibers with diameters ranging from 0.7 to 2.3 μm were obtained by regulating ZP solution concentration and process parameters during the ES process. Optimal loading capacity (LC) and encapsulation efficiency (EE) of OEO in fibrous ZP mats were determined to be 22.28% and 53.68%, respectively, and were achieved using a 35 w/v% ZP ES solution. The encapsulation of OEO was found to be reliant on ZP solution concentration (the enveloping medium). SEM analysis indicates the surface morphology of ZP/OEO electrospun fibers is dependent on ZP solution loading volume, with lower ZP concentrations yielding defective fibrous structures (for example, beaded and spindled-string like morphologies). Furthermore, this loading volume also influences OEO LC, EE, mat water contact angle and oil retention. CCK-8 assay and cell morphology assessment (HEK293T cells) indicate no significant change with electrospun ZP and ZP/OEO fibrous membranes over an 8 h period. Antimicrobial activity assessment using Escherichia coli, suggests composite nonwovens possess sterilization properties; elucidating potential application in active food packaging, food preservation and therefore sustainability. © 2017 Institute of Food Technologists®.

  15. [Fibrous dysplasia of maxilla and the orthodontic treatment. Case report].

    Science.gov (United States)

    Syryńska, Maria; Szyszka, Liliana; Kowalczyk, Robert; Wedrychowska-Szulc, Barbara

    2007-01-01

    Patients who have malocclusions caused by bone diseases come to see the dentist for the orthodontic treatment. One of these diseases is fibrous dysplasia. The aim of this study was to present the patient with the active form of fibrous dysplasia who reported to the Orthodontic Department of Pomeranian Medical University in Szczecin for treatment. We used the patient's own documentation, photos, radiological view and histopathological investigations. The extraoral, clinical examination revealed the asymmetry of the face on the left side, while the intraoral examination showed the convex lesion similar to an egg on the palate which crosses the medial line and clear "distension" of the alveolar bone in the direction of the oral vestibule. The dysplastic lesions are extensive and cause numerous malocclusions and disorders of the symmetry. The radiological and histopathological examinations were added to the clinical examination. The panoramic radiographs have shown the asymmetry and heterogenic structure of the bone with areas of"ground glass". Computer tomography demonstrated bumpy thickening of the zygomatic bone, maxilla, and a great wing of the sphenoid bone and almost completely filled maxillary sinus. The histopathological examination is the confirmation of the diagnosis of fibrous dysplasia. It demonstrates immature bone. The diagnosis of fibrous dysplasia commands the periodic observation and the postponement of the orthodontic treatment in the stage of active development of lesions, but when the overgrowth impairs the function, there is the necessity to use surgical and radical excision to remove lesions. We must pay particular attention to the possibility of malignant transformation of these lesions.

  16. Evaluation of the Moldboard Structure Resistance of the Grader Equipment

    Directory of Open Access Journals (Sweden)

    Carmen Debeleac

    2013-09-01

    Full Text Available In this paper, the author presents a method for evaluation of the moldboard structure resistance of the motor-graders. Usual grader model was chosen to be analyzed by the FEM. Horizontal force of the blade was estimated using the classical soil mechanics theories for cutting soil proposed by McKyes. The simulation results can be useful for structural performance evaluation of these machine used in construction and agricultural fields.

  17. Fracture Resistance, Surface Defects and Structural Strength of Glass

    NARCIS (Netherlands)

    Rodichev, Y.M.; Veer, F.A.

    2010-01-01

    This paper poses the theory that the fracture resistance of basic float glass is dependent on it physicochemical properties and the surface defects fonned under the float glass production, glass processing and handling at the service conditions compose the aggregate basis for structural glass

  18. Pseudotumoral fibrous dysplasia of the maxilla

    International Nuclear Information System (INIS)

    Vanel, D.; Couanet, D.; Piekarski, J.D.; Masselot, J.; Micheau, C.; Schwaab, G.

    1980-01-01

    Clinical, radiological, and histological problems arise relating to fibrous dysplasia of the maxilla. Clinically, 11 of our 39 cases developed so rapidly that the lesions were suspected of being malignant. The histological diagnosis may be very difficult, since any tumoural, reactive, or healing process may simulate fibrous dysplasia. As a general rule, the diagnosis is established most easily by the radiological examination. The radiologist's responsibility is important, as mistakes may have serious consequences. We report four pseudotumoural forms of maxillary sinus fibrous dysplasia. All were characterised clinically by rapid evolution, radiologically by opacity of the sinus with apparent destruction of its wall, and histologically by difficulty in establishing the diagnosis. In two cases indeed, the initial histological interpretation was an osteogenic sarcoma. Due to its excellent densitometric resolution, computed tomography provides an invaluable contribution by displaying the fibrous wall of an intact or even thickened maxillary sinus when conventional radiology has suggested a destructive process. In difficult cases of maxillary fibrous dysplasia, computed tomography should be used as a supplementary investigation to establish the correct diagnosis. (orig.) [de

  19. INVESTIGATION OF THERMAL BEHAVIOR OF MULTILAYERED FIRE RESISTANT STRUCTURE

    Directory of Open Access Journals (Sweden)

    R. GUOBYS

    2016-09-01

    Full Text Available This paper presents experimental and numerical investigations of thermal behavior under real fire conditions of new generation multilayered fire resistant structure (fire door, dimensions H × W × D: 2090 × 980 × 52 mm combining high strength and fire safety. This fire door consists of two steel sheets (thickness 1.5 and 0.7 mm with stone wool ( = 33 kg/m3, k = 0.037 W/mK, E = 5000 N/m2,  = 0.2 insulating layer in between. One surface of the structure was heated in fire furnace for specified period of time of 60 min. Temperature and deformation of opposite surface were measured from outside at selected measuring points during fire resistance test. Results are presented as temperature-time and thermal deformation-time graphs. Experimental results were compared with numerical temperature field simulation results obtained from SolidWorks®Simulation software. Numerical results were found to be in good agreement with experimental data. The percent differences between door temperatures from simulation and fire resistance test don’t exceed 8%. This shows that thermal behaviour of such multilayered structures can be investigated numerically, thus avoiding costly and time-consuming fire resistance tests. It is established that investigated structure should be installed in a way that places thicker steel sheet closer to the potential heat source than thinner one. It is also obtained that stone wool layer of higher density should be used to improve fire resistance of the structure.

  20. Structural origin of resistance drift in amorphous GeTe

    Science.gov (United States)

    Zipoli, Federico; Krebs, Daniel; Curioni, Alessandro

    2016-03-01

    We used atomistic simulations to study the origin of the change of resistance over time in the amorphous phase of GeTe, a prototypical phase-change material (PCM). Understanding the cause of resistance drift is one of the biggest challenges to improve multilevel storage technology. For this purpose, we generated amorphous structures via classical molecular-dynamics simulations under conditions as close as possible to the experimental operating ones of such memory devices. Moreover, we used the replica-exchange technique to generate structures comparable with those obtained in the experiment after long annealing that show an increase of resistance. This framework allowed us to overcome the main limitation of previous simulations, based on density-functional theory, that suffered from being computationally too expensive therefore limited to the nanosecond time scale. We found that resistance drift is caused by consumption of Ge atom clusters in which the coordination of at least one Ge atom differs from that of the crystalline phase and by removal of stretched bonds in the amorphous network, leading to a shift of the Fermi level towards the middle of the band gap. These results show that one route to design better memory devices based on current chalcogenide alloys is to reduce the resistance drift by increasing the rigidity of the amorphous network.

  1. Barley Stem Rust Resistance Genes: Structure and Function

    Directory of Open Access Journals (Sweden)

    Andris Kleinhofs

    2009-07-01

    Full Text Available Rusts are biotrophic pathogens that attack many plant species but are particularly destructive on cereal crops. The stem rusts (caused by have historically caused severe crop losses and continue to threaten production today. Barley ( L. breeders have controlled major stem rust epidemics since the 1940s with a single durable resistance gene . As new epidemics have threatened, additional resistance genes were identified to counter new rust races, such as the complex locus against races QCCJ and TTKSK. To understand how these genes work, we initiated research to clone and characterize them. The gene encodes a unique protein kinase with dual kinase domains, an active kinase, and a pseudokinase. Function of both domains is essential to confer resistance. The and genes are closely linked and function coordinately to confer resistance to several wheat ( L. stem rust races, including the race TTKSK (also called Ug99 that threatens the world's barley and wheat crops. The gene encodes typical resistance gene domains NBS, LRR, and protein kinase but is unique in that all three domains reside in a single gene, a previously unknown structure among plant disease resistance genes. The gene encodes an actin depolymerizing factor that functions in cytoskeleton rearrangement.

  2. Application of Transistors in Textiles: Monitoring Water Transportation Behaviour in Fibrous Assemblies

    Science.gov (United States)

    Chatterjee, Arobindo; Singh, Pratibha; Ghosh, Subrata

    2017-06-01

    Simple semiconductor device has been used for amplifying the analog signals, obtained with the change in electrical resistance in fibrous assembly and converting these amplified copies of signals to digital signals. This paper deals with the application of transistors as amplifier, as well as switch. Different circuit configurations using transistors have been tried for sensing and reciprocating the real time data on suitable display device. It is found that transistors configured as common-emitter amplifiers can precisely sense the liquid at the surface of fibrous assembly at different levels with respect to time.

  3. Dimensional analysis of membrane distillation flux through fibrous membranes

    Science.gov (United States)

    Mauter, Meagan

    We developed a dimensional-analysis-based empirical modeling method for membrane distillation (MD) flux that is adaptable for novel membrane structures. The method makes fewer simplifying assumptions about membrane pore geometry than existing theoretical (i.e. mechanistic) models, and allows selection of simple, easily-measureable membrane characteristics as structural parameters. Furthermore, the model does not require estimation of membrane surface temperatures; it accounts for convective heat transfer to the membrane surface without iterative fitting of mass and heat transfer equations. The Buckingham-Pi dimensional analysis method is tested for direct contact membrane distillation (DCMD) using non-woven/fibrous structures as the model membrane material. Twelve easily-measured variables to describe DCMD operating conditions, fluid properties, membrane structures, and flux were identified and combined into eight dimensionless parameters. These parameters were regressed using experimentally-collected data for multiple electrospun membrane types and DCMD system conditions, achieving R2 values >95%. We found that vapor flux through isotropic fibrous membranes can be estimated using only membrane thickness, solid fraction, and fiber diameter as structural parameters. Buckingham-Pi model DCMD flux predictions compare favorably with previously-developed empirical and theoretical models, and suggest this simple yet theoretically-grounded empirical modeling method can be used practically for predicting MD vapor flux from membrane structural parameters.

  4. Structural basis of protein oxidation resistance: a lysozyme study.

    Science.gov (United States)

    Girod, Marion; Enjalbert, Quentin; Brunet, Claire; Antoine, Rodolphe; Lemoine, Jérôme; Lukac, Iva; Radman, Miroslav; Krisko, Anita; Dugourd, Philippe

    2014-01-01

    Accumulation of oxidative damage in proteins correlates with aging since it can cause irreversible and progressive degeneration of almost all cellular functions. Apparently, native protein structures have evolved intrinsic resistance to oxidation since perfectly folded proteins are, by large most robust. Here we explore the structural basis of protein resistance to radiation-induced oxidation using chicken egg white lysozyme in the native and misfolded form. We study the differential resistance to oxidative damage of six different parts of native and misfolded lysozyme by a targeted tandem/mass spectrometry approach of its tryptic fragments. The decay of the amount of each lysozyme fragment with increasing radiation dose is found to be a two steps process, characterized by a double exponential evolution of their amounts: the first one can be largely attributed to oxidation of specific amino acids, while the second one corresponds to further degradation of the protein. By correlating these results to the structural parameters computed from molecular dynamics (MD) simulations, we find the protein parts with increased root-mean-square deviation (RMSD) to be more susceptible to modifications. In addition, involvement of amino acid side-chains in hydrogen bonds has a protective effect against oxidation Increased exposure to solvent of individual amino acid side chains correlates with high susceptibility to oxidative and other modifications like side chain fragmentation. Generally, while none of the structural parameters alone can account for the fate of peptides during radiation, together they provide an insight into the relationship between protein structure and susceptibility to oxidation.

  5. Structural basis for resistance to diverse classes of NAMPT inhibitors.

    Directory of Open Access Journals (Sweden)

    Weiru Wang

    Full Text Available Inhibiting NAD biosynthesis by blocking the function of nicotinamide phosphoribosyl transferase (NAMPT is an attractive therapeutic strategy for targeting tumor metabolism. However, the development of drug resistance commonly limits the efficacy of cancer therapeutics. This study identifies mutations in NAMPT that confer resistance to a novel NAMPT inhibitor, GNE-618, in cell culture and in vivo, thus demonstrating that the cytotoxicity of GNE-618 is on target. We determine the crystal structures of six NAMPT mutants in the apo form and in complex with various inhibitors and use cellular, biochemical and structural data to elucidate two resistance mechanisms. One is the surprising finding of allosteric modulation by mutation of residue Ser165, resulting in unwinding of an α-helix that binds the NAMPT substrate 5-phosphoribosyl-1-pyrophosphate (PRPP. The other mechanism is orthosteric blocking of inhibitor binding by mutations of Gly217. Furthermore, by evaluating a panel of diverse small molecule inhibitors, we unravel inhibitor structure activity relationships on the mutant enzymes. These results provide valuable insights into the design of next generation NAMPT inhibitors that offer improved therapeutic potential by evading certain mechanisms of resistance.

  6. Congenital fibrous hamartoma of the knee

    International Nuclear Information System (INIS)

    Arioni, Cesare; Bellini, Carlo; Risso, Francesco Maria; Scopesi, Fabio; Serra, Giovanni; Oddone, Mauro; Toma, Paolo; Nozza, Paolo

    2006-01-01

    A full-term male infant presented at birth with a hard swelling of the left knee. The lemon-sized lesion was fixed to the underlying knee muscles, while the overlying skin was stretched and shiny; there was no bruit. Radiography, sonography and MRI suggested a soft-tissue tumour. After surgical excision, histology showed the presence of fibrous and mesenchymal tissue, with mature adipose tissue. Fibrous hamartoma of infancy was diagnosed. Among soft-tissue tumours, fibrous hamartoma of infancy is a rare and benign lesion, occurring in the first 2 years of life. The tumour mainly affects the trunk, axilla, and upper extremities. This infant had unique involvement of the knee. The treatment of choice is local excision. (orig.)

  7. CT Imaging of Craniofacial Fibrous Dysplasia

    Directory of Open Access Journals (Sweden)

    Zerrin Unal Erzurumlu

    2015-01-01

    Full Text Available Fibrous dysplasia is a benign fibroosseous bone dysplasia that can involve single (monostotic or multiple (polyostotic bones. Monostotic form is more frequent in the jaws. It is termed as craniofacial fibrous dysplasia, when it involves, though rarely, adjacent craniofacial bones. A 16-year-old girl consulted for a painless swelling in the right posterior mandible for two years. Panoramic radiography revealed ground-glass ill-defined lesions in the three different regions of the maxilla and mandible. Axial CT scan (bone window showed multiple lesions involving skull base and facial bones. Despite lesions in the skull base, the patient had no abnormal neurological findings. The lesion was diagnosed as fibrous dysplasia based on radiological and histopathological examination. In this paper, CT findings and differential diagnosis of CFD are discussed. CT is a useful imaging technique for CFD cases.

  8. Structural dynamic and resistance to nuclear air blast

    International Nuclear Information System (INIS)

    Qureshi, S.M.

    2003-01-01

    A need exists to design protective shelters attached to specialized facilities against nuclear airbursts, explosive shocks and impacting projectiles. Designing such structures against nuclear and missile impact is a challenging task that needs to be looked into for design methodology formulation and practicability. Structures can be designed for overpressure pulsed generated by a nuclear explosion as well as the scabbing and perforation/punching of an impacting projectile. This paper discuses and formulates the methods of dynamic analysis and design required to undertake such a task. Structural resistance to peak overpressure pulse for a 20 KT weapons and smaller tactical nuclear weapons of 1 KT (16 psi, overpressure) size as a direct air blast overpressure has been considered in design of walls, beams and slabs of a special structure under review. The design of shear reinforcement as lacing is also carried out. Adopting the philosophy of strengthening and hardening can minimize the effect of air blast overpressure and projectile impact. The objective is to avoid a major structural failure. The structure then needs to be checked against ballistic penetration by a range of weapons or be required to resist explosive penetration from the charge detonated in contact with the structure. There is also a dire need to formulate protective guidelines for all existing and future critical facilities. (author)

  9. Craniofacial Fibrous Dysplasia of Zygomaticomaxillary Complex.

    Science.gov (United States)

    Nilesh, Kumar; Punde, Prashant; Parkar, M I

    2017-09-01

    Fibrous dysplasia is a benign bone disease first described by Lichtenstein in 1938. It is characterized by progressive replacement of normal bone with fibro-osseous connective tissue. When the disease involves craniofacial skeleton, it results in significant disfigurement and other functional problems. This paper reports a case of large craniofacial fibrous dysplasia involving zygomaticomaxillary complex in a 24-year old male patient. Clinical presentation and imaging characteristics of the pathology is discussed in detail. The disease caused significant facial asymmetry which was satisfactorily managed by surgical recontouring.

  10. Isolated fibrous dysplasia of the ethmoid sinus.

    Science.gov (United States)

    Yenigun, Alper; Akyuz, Servet

    2015-01-01

    Fibrous dysplasia is a benign fibro-osseous lesion progressing with one or more bone involvements in the skeleton. Even though it is a benign tumor, it may potentially transform into a malignant one. While the most frequently involved zones in the head-neck zone include the maxilla, mandible, parietal, occipital, and temporal zones, the involvement of the ethmoid bone is rather rare. This article presents the case of a female patient who was diagnosed with fibrous dysplasia in the right ethmoid sinus based on the paranasal computerized tomography scan that was taken due to the symptoms of pain around the right eye, pressure, and a feeling of being pushed.

  11. A case of intracranial malignant fibrous histiocytoma

    Directory of Open Access Journals (Sweden)

    Amir Hossein Sarrami

    2011-01-01

    Full Text Available We describe a case of intracranial malignant fibrous histiocytoma which had infiltrated pons, cerebellum and basal surface of left temporal lobe without any visible mass. The patient presented with a sudden loss of consciousness and vomiting. Clinical findings, laboratory tests, imaging and examination of the cerebrospinal fluid tended to establish the diagnosis of an infectious condition than a malignancy. Without any response to the antibiotics and with a progressive deterioration of neurologic and mental condition, the patient died after 20 days. In the autopsy, histological and immunohistochemical study of the brain revealed the diagnosis of malignant fibrous histiocytoma (MFH.

  12. Statistical model for the mechanical behavior of the tissue engineering non-woven fibrous matrices under large deformation.

    Science.gov (United States)

    Rizvi, Mohd Suhail; Pal, Anupam

    2014-09-01

    The fibrous matrices are widely used as scaffolds for the regeneration of load-bearing tissues due to their structural and mechanical similarities with the fibrous components of the extracellular matrix. These scaffolds not only provide the appropriate microenvironment for the residing cells but also act as medium for the transmission of the mechanical stimuli, essential for the tissue regeneration, from macroscopic scale of the scaffolds to the microscopic scale of cells. The requirement of the mechanical loading for the tissue regeneration requires the fibrous scaffolds to be able to sustain the complex three-dimensional mechanical loading conditions. In order to gain insight into the mechanical behavior of the fibrous matrices under large amount of elongation as well as shear, a statistical model has been formulated to study the macroscopic mechanical behavior of the electrospun fibrous matrix and the transmission of the mechanical stimuli from scaffolds to the cells via the constituting fibers. The study establishes the load-deformation relationships for the fibrous matrices for different structural parameters. It also quantifies the changes in the fiber arrangement and tension generated in the fibers with the deformation of the matrix. The model reveals that the tension generated in the fibers on matrix deformation is not homogeneous and hence the cells located in different regions of the fibrous scaffold might experience different mechanical stimuli. The mechanical response of fibrous matrices was also found to be dependent on the aspect ratio of the matrix. Therefore, the model establishes a structure-mechanics interdependence of the fibrous matrices under large deformation, which can be utilized in identifying the appropriate structure and external mechanical loading conditions for the regeneration of load-bearing tissues. Copyright © 2014 Elsevier Ltd. All rights reserved.

  13. Electrospun PVdF-based fibrous polymer electrolytes for lithium ion polymer batteries

    International Nuclear Information System (INIS)

    Kim, Jeong Rae; Choi, Sung Won; Jo, Seong Mu; Lee, Wha Seop; Kim, Byung Chul

    2004-01-01

    This paper discusses the preparation of microporous fibrous membranes from PVdF solutions with different polymer contents, using the electrospinning technique. Electrospun PVdF-based fibrous membranes with average fiber diameters (AFD's) of 0.45-1.38 μm have an apparent porosity and a mean pore size (MPS) of 80-89% and 1.1-4.3 μm, respectively. They exhibited a high uptake of the electrolyte solution (320-350%) and a high ionic conductivity of above 1 x 10 -3 s/cm at room temperature. Their ionic conductivity increased with the decrease in the AFD of the fibrous membrane due to its high electrolyte uptake. The interaction between the electrolyte molecules and the PVdF with a high crystalline content may have had a minor effect on the lithium ion transfer in the fibrous polymer electrolyte, unlike in a nanoporous gel polymer electrolyte. The fibrous polymer electrolyte that contained a 1 M LiPF 6 -EC/DMC/DEC (1/1/1 by weight) solution showed a high electrochemical stability of above 5.0 V, which increased with the decrease in the AFD The interfacial resistance (R i ) between the polymer electrolyte and the lithium electrode slightly increased with the storage time, compared with the higher increase in the interfacial resistance of other gel polymer electrolytes. The prototype cell (MCMB/PVdF-based fibrous electrolyte/LiCoO 2 ) showed a very stable charge-discharge behavior with a slight capacity loss under constant current and voltage conditions at the C/2-rate of 20 and 60 deg. C

  14. Locally Aggressive Fibrous Dysplasia Mimicking Malign Calvarial Lesion.

    Science.gov (United States)

    Ogul, Hayri; Keskin, Emine

    2018-05-01

    Fibrous dysplasia is an unusual benign bone tumor. It is divided into 3 groups as monostotic, polyostotic, and craniofacial form. The authors reported an unusual patient with fibrous dysplasia with an aggressive radiologic appearance.

  15. Extraction of uranium from seawater by the fibrous composite adsorbent

    International Nuclear Information System (INIS)

    Katoh, Shunsaku; Sugasaka, Kazuhiko; Nogi, Tatsuo; Yoshizumi, Nobuo; Mima, Kooji.

    1986-01-01

    The fibrous composite adsorbents consisting of hydrous titanium oxide and activated carbon were prepared with hydrophilic polyacrylonitrile system polymer as a binder under various conditions, and the adsorptive property of the fibrous composite adsorbents for uranium from seawater was examined. The fibrous composite adsorbents which spun under high pressure (10 kg/cm 2 ) was the finest having the largest pore volume. In addition, the amount of uranium adsorbed of the fibrous adsorbent was the largest. The rate of uranium adsorption by the fibrous adsorbent was the same as the rate of uranium adsorption by the powdery adsorbent. The excellent fibrous adsorbent adsorbed 0.23 mg U/g adsorbent for 10 d and 0.65 mg U/g adsorbent for 100 d. The rate of uranium desorption from the fibrous adsorbent by alkali carbonate solution was large, and the uranium in the fibrous adsorbent desorbed 75 % for 8 h and about 100 % for 24 h. (author)

  16. Disrupted bone remodeling leads to cochlear overgrowth and hearing loss in a mouse model of fibrous dysplasia.

    Directory of Open Access Journals (Sweden)

    Omar Akil

    Full Text Available Normal hearing requires exquisite cooperation between bony and sensorineural structures within the cochlea. For example, the inner ear secretes proteins such as osteoprotegrin (OPG that can prevent cochlear bone remodeling. Accordingly, diseases that affect bone regulation can also result in hearing loss. Patients with fibrous dysplasia develop trabecular bone overgrowth resulting in hearing loss if the lesions affect the temporal bones. Unfortunately, the mechanisms responsible for this hearing loss, which could be sensorineural and/or conductive, remain unclear. In this study, we used a unique transgenic mouse model of increased Gs G-protein coupled receptor (GPCR signaling induced by expression of an engineered receptor, Rs1, in osteoblastic cells. These ColI(2.3+/Rs1+ mice showed dramatic bone lesions that histologically and radiologically resembled fibrous dysplasia. We found that ColI(2.3+/Rs1+ mice showed progressive and severe conductive hearing loss. Ossicular chain impingement increased with the size and number of dysplastic lesions. While sensorineural structures were unaffected, ColI(2.3+/Rs1+ cochleae had abnormally high osteoclast activity, together with elevated tartrate resistant acid phosphatase (TRAP activity and receptor activator of nuclear factor kappa-B ligand (Rankl mRNA expression. ColI(2.3+/Rs1+ cochleae also showed decreased expression of Sclerostin (Sost, an antagonist of the Wnt signaling pathway that normally increases bone formation. The osteocyte canalicular networks of ColI(2.3+/Rs1+ cochleae were disrupted and showed abnormal osteocyte morphology. The osteocytes in the ColI(2.3+/Rs1+ cochleae showed increased expression of matrix metalloproteinase 13 (MMP-13 and TRAP, both of which can support osteocyte-mediated peri-lacunar remodeling. Thus, while the ossicular chain impingement is sufficient to account for the progressive hearing loss in fibrous dysplasia, the deregulation of bone remodeling extends to the

  17. Fracture Resistance, Surface Defects and Structural Strength of Glass

    OpenAIRE

    Rodichev, Y.M.; Veer, F.A.

    2010-01-01

    This paper poses the theory that the fracture resistance of basic float glass is dependent on it physicochemical properties and the surface defects fonned under the float glass production, glass processing and handling at the service conditions compose the aggregate basis for structural glass strength assessment. The effect of loading conditions, constructional and technological factors on the engineering strength of glass can be evaluated in certain cases using fracture mechanics with inform...

  18. Structural abnormalities of small resistance arteries in essential hypertension.

    Science.gov (United States)

    Rizzoni, Damiano; Agabiti-Rosei, Enrico

    2012-06-01

    Regardless of the mechanisms that initiate the increase in blood pressure, the development of structural changes in the systemic vasculature is the end result of established hypertension. In essential hypertension, the small arteries smooth muscle cells are restructured around a smaller lumen, and there is no net growth of the vascular wall, while in some secondary forms of hypertension, a hypertrophic remodeling may be detected. Also, in non-insulin-dependent diabetes mellitus, a hypertrophic remodeling of subcutaneous small arteries is present. The results from our own group have suggested that indices of small resistance artery structure, such as the tunica media to internal lumen ratio, may have a strong prognostic significance in hypertensive patients, over and above all other known cardiovascular risk factors. Therefore, the regression of vascular alterations is an appealing goal of antihypertensive treatment. Different antihypertensive drugs seem to have different effect on vascular structure, both in human and in animal models of genetic and experimental hypertension. A complete normalization of small resistance artery structure is demonstrated in hypertensive patients, after long-term and effective therapy with ACE inhibitors, angiotensin II receptor blockers and calcium antagonists. Few data are available in diabetic hypertensive patients; however, blockade of the renin-angiotensin system seems to be effective in this regard. In conclusion, there are several pieces of evidence that suggest that small resistance artery structure may be considered an intermediate endpoint in the evaluation of the effects of antihypertensive therapy; however, there are presently no data available about the prognostic impact of the regression of vascular structural alterations in hypertension and diabetes.

  19. [Fibrous dysplasia of the frontal sinus: a case report].

    Science.gov (United States)

    Keleş, Erol; Kaplama, Mehmet Erkan; Ozkara, Sule; Cobanoğlu, Bengü

    2011-01-01

    Fibrous dysplasia is a rare and indolent benign tumor of bone. Although it is a benign tumor, it has malignant transformation potential. Fibrous dysplasia can involve a single or multiple bones. The maxilla and mandible are the most common sites in the head and neck region. Paranasal sinus involvement is rare. Surgical excision is the preferred treatment of patients with symptomatic fibrous dysplasia. In this article, a 54-year-old male patient diagnosed with fibrous dysplasia of the frontal bone is presented.

  20. Evaluation and histological maturation characteristics of fibrous ...

    African Journals Online (AJOL)

    Evaluation and histological maturation characteristics of fibrous dysplasia and ossifying fibroma: a case series. ... diagnosed as OF and FD were retrieved from the archival records of the Departments of Oral Surgery/Oral Pathology and Histopathology/Morbid Anatomy, Muhimbili University of Health and Allied Sciences.

  1. Steam Reformer With Fibrous Catalytic Combustor

    Science.gov (United States)

    Voecks, Gerald E.

    1987-01-01

    Proposed steam-reforming reactor derives heat from internal combustion on fibrous catalyst. Supplies of fuel and air to combustor controlled to meet demand for heat for steam-reforming reaction. Enables use of less expensive reactor-tube material by limiting temperature to value safe for material yet not so low as to reduce reactor efficiency.

  2. Apparatus for processing fibrous pulp material

    NARCIS (Netherlands)

    Dekker, J.C.; Bouma, H.; Mulder, F.B.M.

    2008-01-01

    The invention relates to an apparatus (1) for processing a flow of pulp comprising fibrous material, in particular pulp comprising cellulose fibres for making paper, said apparatus comprising a drum (2) having a rotational axis (R), an inlet end (3), an outlet end (4) and an inner surface, a

  3. MRI of intracranial meningeal malignant fibrous histiocytoma

    International Nuclear Information System (INIS)

    Ogino, A.; Ochi, M.; Hayashi, K.; Hirata, K.; Hayashi, T.; Yasunaga, A.; Shibata, S.

    1996-01-01

    We describe the CT and MRI findings in a patient with primary intracranial meningeal malignant fibrous histiocytoma (MFH). CT delineated the anatomical relations and MRI aided in tissue characterisation. To our knowledge, this is the first report describing the MRI findings in primary intracranial meningeal MFH. (orig.). With 1 fig

  4. Nanoscale Piezoelectric Properties of Self-Assembled Fmoc-FF Peptide Fibrous Networks.

    Science.gov (United States)

    Ryan, Kate; Beirne, Jason; Redmond, Gareth; Kilpatrick, Jason I; Guyonnet, Jill; Buchete, Nicolae-Viorel; Kholkin, Andrei L; Rodriguez, Brian J

    2015-06-17

    Fibrous peptide networks, such as the structural framework of self-assembled fluorenylmethyloxycarbonyl diphenylalanine (Fmoc-FF) nanofibrils, have mechanical properties that could successfully mimic natural tissues, making them promising materials for tissue engineering scaffolds. These nanomaterials have been determined to exhibit shear piezoelectricity using piezoresponse force microscopy, as previously reported for FF nanotubes. Structural analyses of Fmoc-FF nanofibrils suggest that the observed piezoelectric response may result from the noncentrosymmetric nature of an underlying β-sheet topology. The observed piezoelectricity of Fmoc-FF fibrous networks is advantageous for a range of biomedical applications where electrical or mechanical stimuli are required.

  5. Planar and 3D fibrous polyaniline-based materials for memristive elements.

    Science.gov (United States)

    Malakhova, Yulia N; Korovin, Alexei N; Lapkin, Dmitry A; Malakhov, Sergey N; Shcherban, Valentina V; Pichkur, Eugene B; Yakunin, Sergey N; Demin, Vyacheslav A; Chvalun, Sergey N; Erokhin, Victor

    2017-10-18

    The memristive elements constructed using polymers - polyaniline (PANI) and polyethyleneoxide (PEO) - could be assembled on planar thin films or on 3D fibrous materials. Planar conductive PANI-based materials were made using the Langmuir-Schaefer (LS) method, and the 3D materials - using the electrospinning method which is a scalable technique. We have analyzed the influence of PANI molar mass, natures of solvent and subphase on the crystalline structure, thickness and conductivity of planar LS films, and the influence of PANI molar mass and the PANI-PEO ratio on the morphological and structural characteristics of 3D fibrous materials.

  6. Resistance to antibiotics: limit theorems for a stochastic SIS model structured by level of resistance.

    Science.gov (United States)

    Boëlle, Pierre-Yves; Thomas, Guy

    2016-12-01

    The rise of bacterial resistance to antibiotics is a major Public Health concern. It is the result of two interacting processes: the selection of resistant bacterial strains under exposure to antibiotics and the dissemination of bacterial strains throughout the population by contact between colonized and uncolonized individuals. To investigate the resulting time evolution of bacterial resistance, Temime et al. (Emerg Infect Dis 9:411-417, 2003) developed a stochastic SIS model, which was structured by the level of resistance of bacterial strains. Here we study the asymptotic properties of this model when the population size is large. To this end, we cast the model within the framework of measure valued processes, using point measures to represent the pattern of bacterial resistance in the compartments of colonized individuals. We first show that the suitably normalized model tends in probability to the solution of a deterministic differential system. Then we prove that the process of fluctuations around this limit tends in law to a Gaussian process in a space of distributions. These results, which generalize those of Kurtz (CBMS-NSF regional conference series in applied mathematics, vol 36. Society for Industrial and Applied Mathematics (SIAM), Philadelphia, 1981, chap. 8) on SIR models, support the validity of the deterministic approximation and quantify the rate of convergence.

  7. Performance prediction of PM 2.5 removal of real fibrous filters with a novel model considering rebound effect

    OpenAIRE

    Cai, Rong-Rong; Zhang, Li-Zhi; Yan, Yuying

    2017-01-01

    Fibrous filters have been proved to be one of the most cost-effective way of particulate matters (specifically PM 2.5) purification. However, due to the complex structure of real fibrous filters, it is difficult to accurately predict the performance of PM2.5 removal. In this study, a new 3D filtration modeling approach is proposed to predict the removal efficiencies of particles by real fibrous filters, by taking the particle rebound effect into consideration. A real filter is considered and ...

  8. Non-oxidative and oxidative torrefaction characterization and SEM observations of fibrous and ligneous biomass

    International Nuclear Information System (INIS)

    Chen, Wei-Hsin; Lu, Ke-Miao; Lee, Wen-Jhy; Liu, Shih-Hsien; Lin, Ta-Chang

    2014-01-01

    Highlights: • Non-oxidative and oxidative torrefaction of biomass is studied. • Two fibrous biomasses and two ligneous biomasses are tested. • SEM observations of four biomasses are provided. • Fibrous biomass is more sensitive to O 2 concentration than ligneous biomass. • The performance of non-oxidative torrefaction is better than that of oxidative torrefaction. - Abstract: Oxidative torrefaction is a method to reduce the operating cost of upgrading biomass. To understand the potential of oxidative torrefaction and its impact on the internal structure of biomass, non-oxidative and oxidative torrefaction of two fibrous biomass materials (oil palm fiber and coconut fiber) and two ligneous ones (eucalyptus and Cryptomeria japonica) at 300 °C for 1 h are studied and compared with each other. Scanning electron microscope (SEM) observations are also performed to explore the impact of torrefaction atmosphere on the lignocellulosic structure of biomass. The results indicate that the fibrous biomass is more sensitive to O 2 concentration than the ligneous biomass. In oxidative torrefaction, an increase in O 2 concentration decreases the solid yield. The energy yield is linearly proportional to the solid yield, which is opposite to the behavior of non-oxidative torrefaction. The performance of non-oxidative torrefaction is better than that of oxidative torrefaction. As a whole, ligneous biomass can be torrefied in oxidative environments at lower O 2 concentrations, whereas fibrous biomass is more suitable for non-oxidative torrefaction

  9. Electrospun fibrous scaffolds with continuous gradations in mineral contents and biological cues for manipulating cellular behaviors.

    Science.gov (United States)

    Zou, Bin; Liu, Yaowen; Luo, Xiaomin; Chen, Fang; Guo, Xueqin; Li, Xiaohong

    2012-04-01

    Challenges remain in the generation of heterogeneous tissues and the repairing of interfacial tissue between soft and hard tissues. The development of tissue engineering scaffolds with gradients in composition, structure, mechanical and chemical properties is essential to modulate cellular behaviors in a graded way and potentially support the growth of functionally graded tissues. Integrated with the three-dimensional (3-D) nanofibrous skeletal structure of native extracellular matrix, electrospun fibers with gradients in amino groups were generated in the current study through an aminolysis process by using a microinfusion pump. Gelatin grafts were constructed to create fibrous scaffolds with gradients in hydroxyapatite (HA) contents, crystal size and mechanical properties through in situ mineralization. Plasmid DNA (pDNA) was included during the mineralization process, and gradations in pDNA loading contents were created on fibrous scaffolds on the basis of HA gradients. Obvious gradients in cell density, osteoblastic differentiation and collagen deposition were demonstrated along the long axis of fibrous mats after cell seeding. Gradients in the amount of pDNA released and the expression of target proteins were indicated on the fibrous mats, which offered a temporally and spatially controlled delivery of growth factors in scaffolds. The creation of gradient futures on 3-D fibrous scaffolds may provide physical, chemical and biological cues and result in efficient regeneration of tissues with spatial distributions of the cell proliferation, differentiation, and matrix secretion. Copyright © 2012 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  10. Micromechanics approach to the magnetoelectric properties of laminate and fibrous piezoelectric/magnetostrictive composites

    International Nuclear Information System (INIS)

    Huang Haitao; Zhou, L.M.

    2004-01-01

    We use a micromechanics approach to study the magnetoelectric (ME) properties of the piezoelectric/magnetostrictive composite with a 2-2 laminate structure and a 3-1 fibrous structure. It is found that the 3-1 composite has a higher ME coefficient than the 2-2 one, if the volume ratio of piezoelectric material is the same. The reason is that the 3-1 fibrous composite makes use of the longitudinal piezoelectric response and the piezoelectric voltage constant g 33 is 2-3 times that of g 31 . Generally, a smaller volume ratio of the piezoelectric material will generate a higher ME response. The tensile stress at the piezoelectric/magnetostrictive interface of the 3-1 fibrous composite, however, could be high enough to induce plastic deformation or microcracks, which leads to a ME coefficient lower than the theoretically predicted one

  11. Structural basis of protein oxidation resistance: a lysozyme study.

    Directory of Open Access Journals (Sweden)

    Marion Girod

    Full Text Available Accumulation of oxidative damage in proteins correlates with aging since it can cause irreversible and progressive degeneration of almost all cellular functions. Apparently, native protein structures have evolved intrinsic resistance to oxidation since perfectly folded proteins are, by large most robust. Here we explore the structural basis of protein resistance to radiation-induced oxidation using chicken egg white lysozyme in the native and misfolded form. We study the differential resistance to oxidative damage of six different parts of native and misfolded lysozyme by a targeted tandem/mass spectrometry approach of its tryptic fragments. The decay of the amount of each lysozyme fragment with increasing radiation dose is found to be a two steps process, characterized by a double exponential evolution of their amounts: the first one can be largely attributed to oxidation of specific amino acids, while the second one corresponds to further degradation of the protein. By correlating these results to the structural parameters computed from molecular dynamics (MD simulations, we find the protein parts with increased root-mean-square deviation (RMSD to be more susceptible to modifications. In addition, involvement of amino acid side-chains in hydrogen bonds has a protective effect against oxidation Increased exposure to solvent of individual amino acid side chains correlates with high susceptibility to oxidative and other modifications like side chain fragmentation. Generally, while none of the structural parameters alone can account for the fate of peptides during radiation, together they provide an insight into the relationship between protein structure and susceptibility to oxidation.

  12. Fractal Model for Acoustic Absorbing of Porous Fibrous Metal Materials

    Directory of Open Access Journals (Sweden)

    Weihua Chen

    2016-01-01

    Full Text Available To investigate the changing rules between sound absorbing performance and geometrical parameters of porous fibrous metal materials (PFMMs, this paper presents a fractal acoustic model by incorporating the static flow resistivity based on Biot-Allard model. Static flow resistivity is essential for an accurate assessment of the acoustic performance of the PFMM. However, it is quite difficult to evaluate the static flow resistivity from the microstructure of the PFMM because of a large number of disordered pores. In order to overcome this difficulty, we firstly established a static flow resistivity formula for the PFMM based on fractal theory. Secondly, a fractal acoustic model was derived on the basis of the static flow resistivity formula. The sound absorption coefficients calculated by the presented acoustic model were validated by the values of Biot-Allard model and experimental data. Finally, the variation of the surface acoustic impedance, the complex wave number, and the sound absorption coefficient with the fractal dimensions were discussed. The research results can reveal the relationship between sound absorption and geometrical parameters and provide a basis for improving the sound absorption capability of the PFMMs.

  13. Photovoltage versus microprobe sheet resistance measurements on ultrashallow structures

    DEFF Research Database (Denmark)

    Clarysse, T.; Moussa, A.; Parmentier, B.

    2010-01-01

    recently been observed between junction photovoltage (JPV) based tools and a micrometer-resolution four-point probe (M4PP) tool on a variety of difficult, state-of-the-art sub-32-nm complementary metal-oxide semiconductor structures (low energy and cluster implants, with/without halo, flash- and laser......-based millisecond anneal). Conventional four-point probe tools fail on almost all of these samples due to excessive probe penetration, whereas in several cases variable probe spacing (using a conventional spreading resistance probe tool) [T. Clarysse , Mater. Sci. Eng. R. 47, 123 (2004)] still gives useful values...... to within about 20%-35% due to its limited probe penetration (5-10 nm at 5 g load). M4PP measurements give systematically a sensible and reproducible result. This is also the case for JPV-based sheet resistance measurements, although these appear to be prone to correct calibration procedures...

  14. The interface interaction behavior between E. coli and two kinds of fibrous minerals.

    Science.gov (United States)

    Dai, Qunwei; Han, Linbao; Deng, Jianjun; Zhao, Yulian; Dang, Zheng; Tan, Daoyong; Dong, Faqin

    2017-11-09

    In the present, studies of interaction between human normal flora and fibrous mineral are still lacking. Batch experiments were performed to deal with the interaction of Escherichia coli and two fibrous minerals (brucite and palygorskite), and the interface and liquid phase characteristics in the short-term interaction processes were discussed. The bacterial concentrations, the remnant glucose (GLU), pyruvic acid, and the activity of β-galactosidase and six elements were measured, and the results show that the promoting effect of brucite on the growth of E. coli was more significant than that of palygorskite. FTIR and XRD analysis results also confirmed E. coli has obviously dissolved on brucite and damage effect on palygorskite silicon structure. SEM results show that the interfacial contact degree between E. coli cells and brucite fibers was higher than that of palygorskite. These may be due to the zeta potential difference between E. coli and palygorskite was 14.57-22.37 mV, while it of brucite was 44.04-64.24 mV. The elements dissolving of two fibrous minerals not only increased regularly to liquid EC but also had a good buffer effect to the decrease of liquid pH. Studies of short-term interaction between E. coli and brucite and palygorskite can help to understand the effect of fibrous minerals on microeubiosis of human normal flora and the contribution of microbial behaviors on the fibrous minerals weathering in the natural environment.

  15. Ductile-brittle transition in transverse isotropic fibrous networks

    Science.gov (United States)

    Luo, Guoquan; Shi, Liping; Li, Mingwei; Zhong, Yesheng; He, Xiaodong; Wang, Jiazhi

    2018-01-01

    Anisotropic fibrous networks, especially transverse isotropic fibrous networks, are widely used to model the microstructures of biological tissues, polymer gels, fibrous thermal insulations, and other fibrous materials. In this letter, we build a three-dimensional transverse isotropic fibrous network model and study its mechanical properties along the through-thickness direction. We propose a measurement of anisotropy for transverse isotropic fibrous networks and then study the influence of anisotropy on the networks' mechanical properties, including its elastic modulus, maximum elongation, and stress-strain curve, by means of finite-element simulation. We also study theoretically the influence of anisotropy on maximum elongation. We find that as the anisotropy of the networks becomes stronger, the elastic modulus decreases and the maximum elongation increases, indicating a transition in mechanical properties from brittle to ductile. We identify this transition as the "ductile-brittle transition." This transition can help guide the design and regulate the mechanical properties of a transverse isotropic fibrous network.

  16. Structural perfection and residual electric resistance of tungsten single crystals

    International Nuclear Information System (INIS)

    Tagirova, D.M.; Dyakina, V.P.; Startsev, V.E.; Esin, V.O.

    1997-01-01

    A study was made into residual relative resistance (RRR) and structural perfection (SP) of tungsten single crystals, grown by electron beam zone melting using seeding crystals of several orientations, namely, , , , . The single crystals were of 99.98 and 99.9995 wt.% purity. The RRR value is found to depend on crystallographic orientation of an axis of crystal growth and to correlate with SP. Single crystals of different purity are differ in the nature of orientational dependences. It is shown that the correlation between RRR and SP of crystals is mainly due to conduction electron scattering by subgrain boundaries (internal size effect)

  17. Nitridated fibrous silica (KCC-1) as a sustainable solid base nanocatalyst

    KAUST Repository

    Bouhrara, Mohamed

    2013-09-03

    We observed that support morphology has dramatic effects on the performance of nitridated silica as a base. By simply replacing conventional silica supports (such as SBA-15 and MCM-41) with fibrous nanosilica (KCC-1), we observed multifold enhancement in the catalytic activity of the nitridated solid base for Knoevenagel condensations and transesterification reactions. This enhancement of the activity can be explained by amine accessibility, which is excellent in KCC-1 due to its open and flexible fibrous structure, that facilitates penetration and interaction with basic amine sites. © 2013 American Chemical Society.

  18. Isolated fibrous dysplasia of the ethmoid sinus

    Directory of Open Access Journals (Sweden)

    Alper Yenigun

    2015-01-01

    Full Text Available Fibrous dysplasia is a benign fibro-osseous lesion progressing with one or more bone involvements in the skeleton. Even though it is a benign tumor, it may potentially transform into a malignant one. While the most frequently involved zones in the head–neck zone include the maxilla, mandible, parietal, occipital, and temporal zones, the involvement of the ethmoid bone is rather rare. This article presents the case of a female patient who was diagnosed with fibrous dysplasia in the right ethmoid sinus based on the paranasal computerized tomography scan that was taken due to the symptoms of pain around the right eye, pressure, and a feeling of being pushed.

  19. The health of retired fibrous glass workers.

    Science.gov (United States)

    Enterline, P E; Henderson, V

    1975-03-01

    A total of 416 men, retiring during the period 1945 to 1972 from six plants engaged mainly in the manufacture of fibrous glass insulation, were studied to see how their mortality experience compared with that of white men in the entire United States living in comparable age and time intervals. The mean follow-up period from first exposure was about 30 years. Overall mortality was low and there was no evidence of an excess in respiratory cancer mortality. No mesotheliomas were noted. For 115 men retiring from the same six plants during the period 1945 to 1972 due to a disability the distribution of disabilities by cause was compared with an expected distribution based on the experience of the Social Security Administration. This comparison showed no evidence of any unusual health hazards among fibrous glass workers, except a possible excess in chronic bronchitis.

  20. Global Current Circuit Structure in a Resistive Pulsar Magnetosphere Model

    Science.gov (United States)

    Kato, Yugo. E.

    2017-12-01

    Pulsar magnetospheres have strong magnetic fields and large amounts of plasma. The structures of these magnetospheres are studied using force-free electrodynamics. To understand pulsar magnetospheres, discussions must include their outer region. However, force-free electrodynamics is limited in it does not handle dissipation. Therefore, a resistive pulsar magnetic field model is needed. To break the ideal magnetohydrodynamic (MHD) condition E\\cdot B=0, Ohm’s law is used. This work introduces resistivity depending upon the distance from the star and obtain a self-consistent steady state by time integration. Poloidal current circuits form in the magnetosphere while the toroidal magnetic field region expands beyond the light cylinder and the Poynting flux radiation appears. High electric resistivity causes a large space scale poloidal current circuit and the magnetosphere radiates a larger Poynting flux than the linear increase outside of the light cylinder radius. The formed poloidal-current circuit has width, which grows with the electric conductivity. This result contributes to a more concrete dissipative pulsar magnetosphere model.

  1. Monostotic fibrous dysplasia with Raynaud's phenomenon.

    Science.gov (United States)

    Kumar, K V S Hari; Aravinda, K; Narayanan, K

    2015-01-01

    Fibrous dysplasia (FD) is a benign bone disorder characterized by alteration in bone morphology. Monostotic FD is the commonest variant and affects the craniofacial bones. Raynaud's phenomenon is recurrent vasospasm of the fingers and toes due to cold exposure. The disease is usually idiopathic or secondary to connective tissue disorders. Raynaud's phenomenon is not described previously with FD. We recently encountered two interesting patients of craniofacial monostotic FD with Raynaud's phenomenon and report the same in this report.

  2. Fibrous dysplasia of the paranasal sinuses.

    Science.gov (United States)

    Feldman, M D; Rao, V M; Lowry, L D; Kelly, M

    1986-09-01

    Fibrous dysplasia (FD) of the paranasal sinuses is rare and often presents a diagnostic challenge. It is usually secondary to extension of disease from adjacent bones and is rarely limited to the sinuses. We have described three cases of FD involving the paranasal sinuses, including the first reported case of FD isolated to the sphenoid sinus. A brief update of the clinical aspects, radiographic appearance, diagnosis, and management of craniofacial FD is provided.

  3. High surface area fibrous silica nanoparticles

    KAUST Repository

    Polshettiwar, Vivek

    2014-11-11

    Disclosed are high surface area nanoparticles that have a fibrous morphology. The nanoparticles have a plurality of fibers, wherein each fiber is in contact with one other fiber and each fiber has a length of between about 1 nm and about 5000 nm. Also disclosed are applications of the nanoparticles of the present invention, and methods of fabrication of the nanoparticles of the present invention.

  4. Complementary scintigraphy in polyostotic fibrous dysplasia

    International Nuclear Information System (INIS)

    Murray, I.P.C.; Haindl, W.; Frater, C.J.

    1996-01-01

    A 65-year-old man with a long history of right knee pain complained of discomfort in both hips. An X-ray has identified changes in the pelvis to indicate Paget's disease. Bone scintigraphy after administration of thallium-201 was performed to ascertain the extent of this disorder. The whole body sweep showed multiple areas of abnormal uptake of varying size and intensity. This finding excluded the possibility of malignant change such as osteogenic sarcoma and malignant fibrous hystiocytoma . 2 figs

  5. Postirradiation sarcoma (malignant fibrous histiocytoma) of axilla

    International Nuclear Information System (INIS)

    Hardy, T.J.; An, T.; Brown, P.W.; Terz, J.J.

    1978-01-01

    A case is reported of a patient who developed a histologically unusual sarcoma in the axilla and chest wall 8 years after receiving radiation therapy (6500 rad) for carcinoma of the breast. This sarcoma showed light- and electron-microscopic features of a malignant fibrous histiocytoma, a tumor not documented among 24 previously reported cases of postirradiation sarcoma following the diagnosis of breast carcinoma. In addition, the literature is reviewed and discussed regarding postirradiation sarcoma in general following breast carcinoma

  6. Toxicity and Carcinogenicity Mechanisms of Fibrous Antigorite

    Directory of Open Access Journals (Sweden)

    Michael Balazy

    2007-03-01

    Full Text Available We studied the effects of fibrous antigorite on mesothelial MeT-5A and monocyte-macrophage J774 cell lines to further understand cellular mechanisms induced by asbestos fibers leading to lung damage and cancer. Antigorite is a mineral with asbestiform properties, which tends to associate with chrysotile or tremolite, and frequently occurs as the predominant mineral in the veins of several serpentinite rocks found abundantly in the Western Alps. Particles containing antigorite are more abundant in the breathing air of this region than those typically found in urban ambient air. Exposure of MeT-5A and J774 cells to fibrous antigorite at concentrations of 5-100 μg/ml for 72 hr induced dose-dependent cytotoxicity. Antigorite also stimulated the ROS production, induced the generation of nitrite and PGE2. MeT-5A cells were more sensitive to antigorite than J774 cells. The results of this study revealed that the fibrous antigorite stimulates cyclooxygenase and formation of hydroxyl and nitric oxide radicals. These changes represent early cellular responses to antigorite fibers, which lead to a host of pathological and neoplastic conditions because free radicals and PGE2 play important roles as mediators of tumor pathogenesis. Understanding the mechanisms of the cellular responses to antigorite and other asbestos particles should be helpful in designing rational prevention and treatment approaches.

  7. Fibrous zinc anodes for high power batteries

    Science.gov (United States)

    Zhang, X. Gregory

    This paper introduces newly developed solid zinc anodes using fibrous material for high power applications in alkaline and large size zinc-air battery systems. The improved performance of the anodes in these two battery systems is demonstrated. The possibilities for control of electrode porosity and for anode/battery design using fibrous materials are discussed in light of experimental data. Because of its mechanical integrity and connectivity, the fibrous solid anode has good electrical conductivity, mechanical stability, and design flexibility for controlling mass distribution, porosity and effective surface area. Experimental data indicated that alkaline cells made of such anodes can have a larger capacity at high discharging currents than commercially available cells. It showed even greater improvement over commercial cells with a non-conventional cell design. Large capacity anodes for a zinc-air battery have also been made and have shown excellent material utilization at various discharge rates. The zinc-air battery was used to power an electric bicycle and demonstrated good results.

  8. Structural Characterization of Highly Corrosion-resistant Steel

    Directory of Open Access Journals (Sweden)

    Adriana Lančok

    2015-12-01

    Full Text Available Structural features of novel corrosion-resistant LC 200N steel were investigated. Mössbauer spectrometry was chosen as a principal method of investigation. Surface as well as bulk properties were studied using Conversion Electron Mössbauer Spectrometry and transmission technique, respectively. Complex behaviour of magnetic and non-magnetic phases was identified in the samples by these two techniques. Chemical composition was checked by neutron activation analysis and X-ray fluorescence technique. Structural arrangement was studied by scanning electron microscopy with energy dispersive spectrometry and transmission electron microscopy. They unveiled regions with fairly varied Cr concentrations. Basing on a simple model of two different Cr concentrations, the relative areas of the Mössbauer sextets were modelled by a linear combination of two binomial distributions.

  9. Fetal Sheep Mesenteric Resistance Arteries: Functional and Structural Maturation.

    Science.gov (United States)

    Müller, Julia J; Schwab, Matthias; Rosenfeld, Charles R; Antonow-Schlorke, Iwa; Nathanielsz, Peter W; Rakers, Florian; Schubert, Harald; Witte, Otto W; Rupprecht, Sven

    2017-01-01

    Fetal blood pressure increases during late gestation; however, the underlying vascular mechanisms are unclear. Knowledge of the maturation of resistance arteries is important to identify the mechanisms and vulnerable periods for the development of vascular dysfunction in adulthood. We determined the functional and structural development of fetal sheep mesenteric resistance arteries using wire myography and immunohistochemistry. Media mass and distribution of myosin heavy-chain isoforms showed no changes between 0.7 (100 ± 3 days) and 0.9 (130 ± 3 days) gestation. However, from 0.7 to 0.9 gestation, the resting wall tension increased accompanied by non-receptor-dependent (potassium) and receptor-dependent (noradrenaline; endothelin-1) increases in vasocontraction. Angiotensin II had no contractile effect at both ages. Endothelium-dependent relaxation to acetylcholine and prostaglandin E2 was absent at 0.7 but present at 0.9 gestation. Augmented vascular responsiveness was paralleled by the maturation of sympathetic and sensory vascular innervation. Non-endothelium-dependent relaxation to nitric oxide showed no maturational changes. The expression of vasoregulator receptors/enzymes did not increase between 0.7 and 0.9 gestation. Vascular maturation during late ovine gestation involves an increase in resting wall tension and the vasoconstrictor and vasodilator capacity of the mesenteric resistance arteries. Absence of structural changes in the tunica media and the lack of an increase in vasoregulator receptor/enzyme expression suggest that vasoactive responses are due to the maturation of intracellular pathways at this gestational age. © 2017 S. Karger AG, Basel.

  10. Development of New Type Seawater Resistant Steel and the Research of Its Structure and Corrosion Resistance

    Science.gov (United States)

    Yin, Baoliang; Yin, Shaojiang; Liu, Zhiyong; Wang, Yunge; Yu, Hao; Li, Haixu; Zhou, Tao

    This paper investigated two kinds of corrosion resistant low alloy steels depending on the environment of the North China see (Steel S) and South China sea (Steel N), respectively. The mechanical and corrosion properties of the two steels were analyzed in this paper. Tin was added into both steels to improve the corrosion resistance. Structure and mechanical properties of the two steels were detected, and the results revealed that the microstructures of both steels were ferrite and little divorced pearlite. The yield strength and impact toughness at -40°C of the steel S are 423MPa and 98 J, respectively. The yield strength and impact toughness at -40°C of the steel N are 437 MPa and 70 J, respectively. The properties mentioned above met or even exceeded the requirement (yield strength 355 MPa, toughness 34 J) in these areas. The corrosion resistant properties of the two steels were also investigated via the means of immersion test and electrochemical experiment. The immersion test indicated that the corrosion rate of steel S and steel N was 0.00938 mg/h·cm2 and 0.00838 mg/h·cm2, respectively, when completely immersed for 168 hours, and the corrosion rate was much lower than that of E36. The Electrochemical experiments showed that the corrosion potential (Ecorr) of both steels was higher in contrast to E36, which indicated a lower corrosion trend.

  11. Polyelectrolyte-complex nanostructured fibrous scaffolds for tissue engineering

    International Nuclear Information System (INIS)

    Verma, Devendra; Katti, Kalpana S.; Katti, Dinesh R.

    2009-01-01

    In the current work, polyelectrolyte complex (PEC) fibrous scaffolds for tissue engineering have been synthesized and a mechanism of their formation has been investigated. The scaffolds are synthesized using polygalacturonic acid and chitosan using the freeze drying methodology. Highly interconnected pores of sizes in the range of 5-20 μm are observed in the scaffolds. The thickness of the fibers was found to be in the range of 1-2 μm. Individual fibers have a nanogranular structure as observed using AFM imaging. In these scaffolds, PEC nanoparticles assemble together at the interface of ice crystals during freeze drying process. Further investigation shows that the freezing temperature and concentration have a remarkable effect on structure of scaffolds. Biocompatibility studies show that scaffold containing chitosan, polygalacturonic acid and hydroxyapatite promotes cell adhesion and proliferation. On the other hand, cells on scaffolds fabricated without hydroxyapatite nanoparticles showed poor adhesion.

  12. Estimating the Sabine absorption coefficient of fibrous materials for various backing conditions

    DEFF Research Database (Denmark)

    Jeong, Cheol-Ho

    2017-01-01

    Since absorber manufacturers cannot provide the absorption coefficients for all possible mounting conditions, acousticians have difficulties knowing the absorption characteristics of their own configurations. This paper aims to predict the Sabine absorption coefficient for various mounting...... conditions by extracting the air flow resistivity of the test specimen and the frequency-dependent effect of the chamber on the measured absorption coefficients. Two homogeneous fibrous absorbers are measured for experimental validation, showing good agreements between the predictions and measurements...

  13. Electro spun Polyamide 4.6 Nano fibrous Nonwoven: Parameter Study and Characterization

    International Nuclear Information System (INIS)

    Schoenmaker, B.De.; Schueren, L.V.; Ceylan, O.; Clerck, K.De.

    2012-01-01

    The aliphatic polyamide 4.6 (PA 4.6) has unique properties compared to the commonly used polyamides 6 (PA 6) and 6.6 (PA 6.6). The purpose of this paper is to produce uniform and reproducible nano fibrous PA 4.6 structures. Therefore, a mixture of the solvent formic acid and the non solvent acetic acid is used to dissolve and electro spin the PA 4.6. First the steady-state behaviour of the process and the boundary limits of the solution parameters needed for steady-state electro spinning are investigated. Subsequently, the effect of several solution and process parameters on the fibre morphology is examined, using microscopic techniques and thermal analysis. The polyamide concentration is found to be the dominant parameter affecting the fibre diameter and morphology. Furthermore, tensile tests are performed on up scaled nano fibrous structures and electro spun under optimised steady-state conditions. It is shown that the PA 4.6 nano fibrous structures, compared to nano fibrous nonwoven s of PA 6 and PA 6.6, have a higher stress and strain at break.

  14. Anti-inflammatory, anti-bacterial, and cytotoxic activity of fibrous clays.

    Science.gov (United States)

    Cervini-Silva, Javiera; Nieto-Camacho, Antonio-; Ramírez-Apan, María Teresa; Gómez-Vidales, Virginia; Palacios, Eduardo; Montoya, Ascención; Ronquillo de Jesús, Elba

    2015-05-01

    Produced worldwide at 1.2m tons per year, fibrous clays are used in the production of pet litter, animal feed stuff to roof parcels, construction and rheological additives, and other applications needing to replace long-fiber length asbestos. To the authors' knowledge, however, information on the beneficial effects of fibrous clays on health remains scarce. This paper reports on the anti-inflammatory, anti-bacterial, and cytotoxic activity by sepiolite (Vallecas, Spain) and palygorskite (Torrejon El Rubio, Spain). The anti-inflammatory activity was determined using the 12-O-tetradecanoylphorbol-13-acetate (TPA) and myeloperoxidase (MPO) methods. Histological cuts were obtained for quantifying leukocytes found in the epidermis. Palygorkite and sepiolite caused edema inhibition and migration of neutrophils ca. 68.64 and 45.54%, and 80 and 65%, respectively. Fibrous clays yielded high rates of infiltration, explained by cleavage of polysomes and exposure of silanol groups. Also, fibrous clays showed high inhibition of myeloperoxidase contents shortly after exposure, but decreased sharply afterwards. In contrast, tubular clays caused an increasing inhibition of myeloperoxidase with time. Thus, clay structure restricted the kinetics and mechanism of myeloperoxidase inhibition. Fibrous clays were screened in vitro against human cancer cell lines. Cytotoxicity was determined using the protein-binding dye sulforhodamine B (SRB). Exposing cancer human cells to sepiolite or palygorskite showed growth inhibition varying with cell line. This study shows that fibrous clays served as an effective anti-inflammatory, limited by chemical transfer and cellular-level signals responding exclusively to an early exposure to clay, and cell viability decreasing significantly only after exposure to high concentrations of sepiolite. Copyright © 2015 Elsevier B.V. All rights reserved.

  15. Mega-mining in Mexico. Structural reforms and resistance

    Directory of Open Access Journals (Sweden)

    Darcy Tetreault

    2013-11-01

    Full Text Available This article analyzes the structural causes of social environmental conflicts around mega-mining in Mexico and describes the emergence and coordination of resistance movements. It argues that neoliberal reforms have facilitated ‘accumulation by dispossession’ on two levels: first, by transferring public resources in the form of mineral reserves and state-run mining companies to the private sector; and second, bydispossessing smallholder farmers and indigenous communities of their land, water and cultural landscapes, in order to allow mining companies to carry out their activities. Furthermore, it argues that some factions of the resistance movements reflect ‘the environmentalism of the poor’ insofar as they seek to maintain natural resources outside of the sphere of the capitalist mode of production. Through a systematic revision of newspaper articles, blogs and scholarly publications, 29 high-profile eco-territorial mining conflicts are identified and a preliminary analysis of these is provided.

  16. Scalable, ultra-resistant structural colors based on network metamaterials

    KAUST Repository

    Galinski, Henning

    2017-05-05

    Structural colors have drawn wide attention for their potential as a future printing technology for various applications, ranging from biomimetic tissues to adaptive camouflage materials. However, an efficient approach to realize robust colors with a scalable fabrication technique is still lacking, hampering the realization of practical applications with this platform. Here, we develop a new approach based on large-scale network metamaterials that combine dealloyed subwavelength structures at the nanoscale with lossless, ultra-thin dielectric coatings. By using theory and experiments, we show how subwavelength dielectric coatings control a mechanism of resonant light coupling with epsilon-near-zero regions generated in the metallic network, generating the formation of saturated structural colors that cover a wide portion of the spectrum. Ellipsometry measurements support the efficient observation of these colors, even at angles of 70°. The network-like architecture of these nanomaterials allows for high mechanical resistance, which is quantified in a series of nano-scratch tests. With such remarkable properties, these metastructures represent a robust design technology for real-world, large-scale commercial applications.

  17. Fibrous dysplasia of the maxillary sinus: case report

    OpenAIRE

    Vijayalakshmi Subramaniam; Adarsha Tuluvinakoppa Vasudeva Herle

    2010-01-01

    Introduction and objective: Fibrous dysplasia is a non-neoplastic lesion of unknown origin with one-fourth involving head and neck. The aim of this paper is to report a case of fibrous dysplasia of the maxillary sinus, describing its clinical presentation, radiological features, histopathological appearance and surgical management. Case report: 3-year-old female patient who presented with a history of fullness of the right cheek and intraoral swelling was diagnosed to have fibrous dysplasia o...

  18. Postirradiation sarcoma (malignant fibrous histiocytoma) following cervix cancer

    International Nuclear Information System (INIS)

    Pinkston, J.A.; Sekine, Ichiro.

    1980-12-01

    A case of postirradiation sarcoma is described. The tumor, a malignant fibrous histiocytoma, occurred in the radiation field 11 years following postoperative external beam radiation therapy (7,000 rad) for carcinoma of the cervix. Reports of postirradiation malignant fibrous histiocytoma are rare, and the occurrence of this neoplasm following treatment for cervix cancer has not previously been described. The literature concerning postirradiation bone and soft tissue sarcomas is briefly reviewed, with special attention to malignant fibrous histiocytomas. (author)

  19. Micropatterned coculture of vascular endothelial and smooth muscle cells on layered electrospun fibrous mats toward blood vessel engineering.

    Science.gov (United States)

    Li, Huinan; Liu, Yaowen; Lu, Jinfu; Wei, Jiaojun; Li, Xiaohong

    2015-06-01

    A major challenge in vascular engineering is the establishment of proper microenvironment to guide the spatial organization, growth, and extracellular matrix (ECM) productions of cells found in blood vessels. In the current study, micropatterned fibrous mats with distinct ridges and grooves of different width were created to load smooth muscle cells (SMCs), which were assembled by stacking on vascular endothelial cell (EC)-loaded flat fibrous mats to mimic the in vivo-like organized structure of blood vessels. SMCs were mainly distributed in the ridges, and aligned fibers in the patterned regions led to the formation of elongated cell bodies, intense actin filaments, and expressions of collagen I and α-smooth muscle actin in a parallel direction with fibers. ECs spread over the flat fibrous mats and expressed collagen IV and laminin with a cobblestone-like feature. A z-stack scanning of fluorescently stained fibrous mats indicated that SMCs effectively infiltrated into fibrous scaffolds at the depth of around 200 μm. Compared with SMCs cultured alone, the coculture with ECs enhanced the proliferation, infiltration, and cytoskeleton elongation of SMCs on patterned fibrous mats. Although the coculture of SMCs made no significant difference in the EC growth, the coculture system on patterned fibrous scaffolds promoted ECM productions of both ECs and SMCs. Thus, this patterned fibrous configuration not only offers a promising technology in the design of tissue engineering scaffolds to construct blood vessels with durable mechanical properties, but also provides a platform for patterned coculture to investigate cell-matrix and cell-cell interactions in highly organized tissues. © 2014 Wiley Periodicals, Inc.

  20. Malignant solitary fibrous tumor metastatic to the orbit.

    Science.gov (United States)

    Glazer-Hockstein, Carolyn; Syed, Nasreen A; Warhol, Michael; Gausas, Roberta E

    2004-11-01

    A 61-year-old man with a history of malignant solitary fibrous tumor of the chest had development of unusual sites of metastasis involving the sphenoid wing of the orbit and soft tissues of the cheek. He was found to have a solitary fibrous tumor, an uncommon type of spindle cell neoplasm that most often arises in the pleura, which was metastatic to the orbit. This is the first reported case of malignant solitary fibrous tumor metastatic to the orbit. The clinical and histopathologic findings of metastatic malignant solitary fibrous tumor are described.

  1. Imaging Findings of Fibrous Hamartoma of Infancy

    Energy Technology Data Exchange (ETDEWEB)

    Rho, Byung Hak; Lee, Hee Jung; Kwon, Sun Young [Dongsan Medical Center, Keimyung University College of Medicine, Daegu (Korea, Republic of)

    2009-09-15

    We wanted to evaluate the imaging findings of fibrous hamartoma of infancy (FHI). We retrospectively reviewed the clinical presentation and the sonographic (n = 5) and CT (n = 3) findings of 5 cases of surgically/pathologically confirmed FHI. The sonographic findings were evaluated according to the location, size, internal echogenicity and vascularity. The CT findings were evaluated according to the attenuation of the mass on both the pre- (n = 3) and postcontrast (n = 2) scans. The image findings were correlated with the pathologic findings. The mean age was 14.8 months (range, 7 months - 3 years). The location of lesions was all in the fatty layer of the back (n = 4) and upper arm (n = 1). All the lesions demonstrated-hypertrichosis on the overlying skin. The lesions measured 31.2 mm in the longest diameter (range: 18 mm - 50 mm). The sonographic findings were purely solid, heterogeneously hyperechoic and hypovacular for all the cases. The internal architecture revealed a 'layering' appearance (n = 3). The CT findings demonstrated isoattenuation, as compared to the adjacent muscle on both the pre- and postcontrast CT scans. The pathologic correlation demonstrated a characteristic 'organoid' mixture of fibrous, mucoid and fatty tissues in all cases. The diagnosis of FHI can be suggested by the sonographic findings of a superficially located, heterogeneous solid mass with a 'layering' appearance in the fatty layer of the back or arms of infants with local hypertrochosis on the overlying skin.

  2. Angiomatoid fibrous histiocytoma: novel MR imaging findings

    Energy Technology Data Exchange (ETDEWEB)

    Martinez, Salutario J.; Vinson, Emily N. [Duke University Medical Center, Department of Radiology, Durham, NC (United States); Moreno, Courtney Coursey [Emory University School of Medicine, Department of Radiology and Imaging Sciences, Atlanta, GA (United States); Dodd, Leslie G. [University of North Carolina School of Medicine, Department of Pathology and Laboratory Medicine, Chapel Hill, NC (United States); Brigman, Brian E. [Duke University Medical Center, Department of Orthopedic Surgery, Durham, NC (United States)

    2016-05-15

    To describe novel MR imaging features, and clinical characteristics of soft tissue angiomatoid fibrous histiocytoma (AFH) at presentation, local recurrence, and metastases. We described the MRI findings of six cases of histologically proven AFH. Pathologic findings, clinical presentation, and outcome were reviewed. Lesions were primarily cystic. At initial presentation, tumors were surrounded by low signal intensity fibrous pseudocapsule. High signal intensity consistent with the lymphoplasmacytic infiltrate was seen in T2-weighted and post-contrast images as a rim over the hypointense pseudocapsule (double rim sign). High signal intensity infiltrating tumoral cords extended into adjacent tissues, through pseudocapsular defects on T2-weighted and post-contrast images. The cystic component and tumor cell nodularity were demonstrated at post-contrast images. Clinically, lesions were often thought to be benign, underwent marginal resection, developed local recurrence, and one developed second recurrence consisting of metastases. Recurrent tumors appeared as multiple masses, misinterpreted as post-surgical changes. An intramuscular recurrence demonstrated double rim and infiltrating margin. A predominantly well-circumscribed, primarily cystic mass with double-rim and marginal infiltration on MRI suggests the possibility of AFH, in particular in child or young adult. Inclusion of these novel observations in AFH differential diagnosis may have a significant impact on treatment and prevention of recurrence. (orig.)

  3. Effect of temperature on structure and corrosion resistance for ...

    Indian Academy of Sciences (India)

    electroless nickel plating, etc. It is well known that electroless plating is an effective cor- rosion resistance method [5–7]. In recent years, NiWP alloy coatings prepared by electroless plating have been widely used to provide some excellent properties like high corrosion resistance and wear resistance, and to obtain uniform ...

  4. Plant resistance genes : their structure, function and evolution

    NARCIS (Netherlands)

    Takken, F.L.W.; Joosten, M.H.A.J.

    2000-01-01

    Plants have developed efficient mechanisms to avoid infection or to mount responses that render them resistant upon attack by a pathogen. One of the best-studied defence mechanisms is based on gene-for-gene resistance through which plants, harbouring specific resistance (R) genes, specifically

  5. Applications of fibrous substrates containing insolubilized phase change polymers

    Science.gov (United States)

    Vigo, Tyrone L.; Bruno, Joseph S.

    1993-01-01

    Incorporation of polyethylene glycols into fibrous substrates produces several improved functional properties when they are insolubilized by crosslinking with a methylolamide resin or by polyacetal formation by their reaction with glyoxal. The range of molecular weights of polyols that may be insolubilized is broad as are the curing conditions (0.25-10 min at 80-200C). Most representative fiber types and blends (natural and synthetic) and all types of fabric constructions (woven, nonwoven and knit) have been modified by incorporation of the bound polyols. The most novel property is the thermal adaptability of the modified substrates to many climatic conditions. This adaptability is due to the high latent heat of the crosslinked polyols that function as phase change materials, the hydrophilic nature of the crosslinked polymer and its enhanced thermal conductivity. Other enhanced properties imparted to fabrics include flex and flat abrasion, antimicrobial activity, reduced static charge, resistance to oily soils, resiliency, wind resistance and reduced lint loss. Applications commercialized in the U.S. and Japan include sportswear and skiwear. Several examples of electric sets of properties useful for specific end uses are given. In addition, other uses are biomedical horticultural, aerospace, indoor insulation, automotive interiors and components and packaging material.

  6. Resistive foil edge grading for accelerator and other high voltage structures

    Science.gov (United States)

    Caporaso, George J.; Sampayan, Stephen F.; Sanders, David M.

    2014-06-10

    In a structure or device having a pair of electrical conductors separated by an insulator across which a voltage is placed, resistive layers are formed around the conductors to force the electric potential within the insulator to distribute more uniformly so as to decrease or eliminate electric field enhancement at the conductor edges. This is done by utilizing the properties of resistive layers to allow the voltage on the electrode to diffuse outwards, reducing the field stress at the conductor edge. Preferably, the resistive layer has a tapered resistivity, with a lower resistivity adjacent to the conductor and a higher resistivity away from the conductor. Generally, a resistive path across the insulator is provided, preferably by providing a resistive region in the bulk of the insulator, with the resistive layer extending over the resistive region.

  7. Case report 525: Benign fibrous histiocytoma (BFH) of thumb

    International Nuclear Information System (INIS)

    Statz, E.M.; Philipps, E.; Pochebit, S.M.; Cooper, A.; Leslie, B.M.

    1989-01-01

    A case was presented of benign fibrous histiocytoma (BFH) involving the distal phalanx of the thumb, a location heretofore not described in the literature. The distinction between BFH and other lesions (e.g. non-ossifying fibroma) was considered in depth. The distinction between benign and malignant fibrous histiocytoma was also described. (orig.)

  8. Marfan syndrome with multiseptate pneumothorax and mandibular fibrous dysplasia

    Directory of Open Access Journals (Sweden)

    Kate A

    2009-01-01

    Full Text Available We describe a rare case of pneumothorax due to Marfan syndrome associated with fibrous dysplasia of the mandible. Marfan syndrome and fibrous dysplasia were possibly due to a common etiological factor. The association between the two and other tumors described in literature related to Marfan syndrome is discussed.

  9. Fibrous microcapsules and methods of assembly and use thereof

    Energy Technology Data Exchange (ETDEWEB)

    Stupp, Samuel; Rozkiewicz, Dorota

    2015-01-27

    The present invention relates to assembly of peptide amphiphiles and biopolymers into fibrous microcapsules, and uses thereof. In particular, the present invention provides devices, compositions, and methods for interfacial self-assembly of peptide amphiphiles and biopolyments into fibrous microcapsules, and uses thereof.

  10. Heat transfer in Rockwool modelling and method of measurement. The effect of natural convection on heat transfer in fibrous materials

    Energy Technology Data Exchange (ETDEWEB)

    Dyrboel, Susanne

    1998-05-01

    Fibrous materials are some of the most widely used materials for thermal insulation. In this project the focus of interest has been on fibrous materials for building application. Interest in improving the thermal properties of insulation materials is increasing as legislation is being tightened to reduce the overall energy consumption. A knowledge of the individual heat transfer mechanisms - whereby heat is transferred within a particular material is an essential tool to improve continuously the thermal properties of the material. Heat is transferred in fibrous materials by four different transfer mechanisms: conduction through air, conduction through fibres, thermal radiation and convection. In a particular temperature range the conduction through air can be regarded as a constant, and conduction through fibres is an insignificant part of the total heat transfer. Radiation, however, constitutes 25-40% of the total heat transfer in light fibrous materials. In Denmark and a number of other countries convection in fibrous materials is considered as non-existent when calculating heat transmission as well as when designing building structures. Two heat transfer mechanisms have been the focus of the current project: radiation heat transfer and convection. The radiation analysis serves to develop a model that can be used in further work to gain a wider knowledge of the way in which the morphology of the fibrous material, i.e. fibre diameter distribution, fibre orientation distribution etc., influences the radiation heat transfer under different conditions. The convection investigation serves to examine whether considering convection as non-existent is a fair assumption to use in present and future building structures. The assumption applied in practically is that convection makes a notable difference only in very thick insulation, at external temperatures below -20 deg. C, and at very low densities. For large thickness dimensions the resulting heat transfer through the

  11. Preparation of micro/nano-fibrous brushite coating on titanium via chemical conversion for biomedical applications

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Bing [Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials, Ministry of Education, Shandong University, Ji’nan 250061 (China); School of Materials Science and Engineering, Shandong University, Ji’nan, 250061 (China); Suzhou Institute, Shandong University, Suzhou, 215123 (China); Guo, Yong-yuan [Orthopedic Department, Qilu Hospital of Shandong University, Ji’nan, 250012 (China); Xiao, Gui-yong [Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials, Ministry of Education, Shandong University, Ji’nan 250061 (China); School of Materials Science and Engineering, Shandong University, Ji’nan, 250061 (China); Suzhou Institute, Shandong University, Suzhou, 215123 (China); Lu, Yu-peng, E-mail: biosdu@sdu.edu.cn [Key Laboratory for Liquid-Solid Structural Evolution and Processing of Materials, Ministry of Education, Shandong University, Ji’nan 250061 (China); School of Materials Science and Engineering, Shandong University, Ji’nan, 250061 (China); Suzhou Institute, Shandong University, Suzhou, 215123 (China)

    2017-03-31

    Highlights: • A chemical conversion brushite coating was prepared on titanium. • The coating exhibits fibrous morphology in micro/nano-scale. • The surface of the coating shows high hydrophilicity and corrosion resistance in the simulated body fluid. • An improvement of cell response was observed on the surface of coated Ti compared to that of the uncoated. - Abstract: Calcium phosphate coatings have been applied on the surface of Ti implants to realize better osseointegration. The formation of dicalcium phosphate dihydrate (CaHPO{sub 4}·2H{sub 2}O), mineralogically named brushite on pure Ti substrate has been investigated via chemical conversion method. Coating composition and microstructure have been investigated by X-ray diffractometer, Fourier transform infrared spectrometer and field emission scanning electron microscope. The results reveal that the coatings are composed of high crystalline brushite with minor scholzite (CaZn{sub 2}(PO{sub 4}){sub 2}·2H{sub 2}O). A micro/nano-scaled fibrous morphology can be produced in the acidic chemical conversion bath with pH 5.00. The surface of the fibrous brushite coating exhibits high hydrophilicity and corrosion resistance in the simulated body fluid. The osteoblast cells grow and spread actively on the coated samples and the proliferation numbers and alkaline phosphate activities of the cells improve significantly compared to the uncoated Ti. It is suggested that the micro/nano-fibrous brushite coating can be a potential approach to improve the osteoinductivity and osteoconductivity of Ti implant, due to its similarity in morphology and dimension to inorganic components of biological hard tissues, and favorable responses to the osteoblasts.

  12. Impact of Corrugated Paperboard Structure on Puncture Resistance

    Directory of Open Access Journals (Sweden)

    Vaidas Bivainis

    2015-03-01

    Full Text Available Thanks to its excellentprotective properties, lightness, a reasonable price, and ecology, corrugated paperboardis one of the most popular materials used in the production of packaging for variousproducts. During transportation or storage, packaging with goods can be exposedto the mass of other commodities, dropping from heights and transportationshock loads, which can lead to their puncture damage. Depending on the purposeand size of the packaging, the thickness, grammage, constituent paper layers,numbers of layers and type of fluting of corrugated paperboard used in itsproduction differ. A standard triangular prism, corrugated paperboard fixationplates and a universal tension-compression machine were used to investigate theimpact of corrugated paperboard structure and other parameters on the punctureresistance of the material. The investigation determines the maximum punctureload and estimates energy required to penetrate the corrugated paperboard. Itwas found that the greatest puncture resistance is demonstrated by paperboardwith a larger number of corrugating flutings and the board produced from harderpaper with a smaller amount of recycled paper. It was established that thegrammage of three-layered paperboard with two different fluting profiles has thegreatest impact on the level of static puncture energy.DOI: http://dx.doi.org/10.5755/j01.ms.21.1.5713

  13. A solitary fibrous tumor of the kidney

    Directory of Open Access Journals (Sweden)

    Anuruddha M Abeygunasekera

    2015-01-01

    Full Text Available A solitary fibrous tumor (SFT is an uncommon spindle cell neoplasm that usually occurs in the pleura, but may occur in extrapleural sites. Its occurrence in the kidney is rare. We report a SFT, clinically thought to be a renal cell carcinoma arising in the kidney of a 68-year-old female. The tumor was well-circumscribed and composed of a mixture of spindle cells and dense collagenous bands. Immunohistochemical studies revealed reactivity for CD34, CD99, and Bcl-2 protein, with no staining for keratin or muscle markers, confirming the diagnosis. The immunohistochemical study was the key to diagnosis. Several younger members of her family had colorectal and lung cancers suggesting the possibility of a familial or genetic susceptibility.

  14. Compressibility of air in fibrous materials

    DEFF Research Database (Denmark)

    Tarnow, Viggo

    1996-01-01

    The dynamic compressibility of air in fibrous materials has been computed for two assumed configurations of fibers which are close to the geometry of real fiber materials. Models with parallel cylinders placed in a regular square lattice and placed randomly are treated. For these models...... the compressibility is computed approximately from the diameter and mean distances between cylinders. This requires calculation of the air temperature, which is calculated for cylinders in a regular lattive by the Wigner-Seitz cell approximation. In the case of random placement, the calculation is done by a summation...... over thermal waves from all fibers, and by a self-consistent procedure. Figuren of the compressibility in the frequency range 10-100 000 Hz, are given for diameter of the cylinders of 6.8 µm, and mean distances between them from 50 to 110 µm, which corresponds to glass wool with a density of 40 to 16...

  15. Primary Malignant Fibrous Histiocytoma: A Rare Case

    Directory of Open Access Journals (Sweden)

    Anastasios Katsourakis

    2011-01-01

    Full Text Available Malignant fibrous histiocytoma (MFH of the small intestine is an extremely rare condition. It occurs most commonly in the extremities and the trunk. We report a case of a 67-year-old woman who admitted with fever, myalgia, and altered status. After thorough investigation, a tumor of the jejunum was found. The patient underwent complete surgical removal of the tumor. A diagnosis of MFN (undifferentiated high-grade pleomorphic sarcoma was made. The patient received adjuvant chemotherapy with Gemcitabine. Two years after the operation, the patient died due to recurrence of the disease. MFH of the small intestine is an extremely rare neoplasm with an aggressive biological behaviour. In this paper, pathogenesis, natural history, and treatment are reviewed.

  16. Solving RNA's structural secrets: interaction with antibodies and crystal structure of a nuclease resistant RNA

    International Nuclear Information System (INIS)

    Wallace, S.T.

    1998-10-01

    This Ph.D. thesis concerns the structural characterization of RNA. The work is split into two sections: 1) in vitro selection and characterization of RNAs which bind antibiotics and 2) crystal structure of a nuclease resistant RNA molecule used in antisense applications. Understanding antibiotic-RNA interactions is crucial in aiding rational drug design. We were interested in studying antibiotic interactions with RNAs small enough to characterize at the molecular and possibly at the atomic level. In order to do so, we previously performed in vitro selection to find small RNAs which bind to the peptide antibiotic viomycin and the aminoglycoside antibiotic streptomycin. The characterization of the viomycin-binding RNAs revealed the necessity of a pseudoknot-structure in order to interact with the antibiotic. The RNAs which were selected to interact with streptomycin require the presence of magnesium to bind the antibiotic. One of the RNAs, upon interacting with streptomycin undergoes a significant conformational change spanning the entire RNA sequence needed to bind the antibiotic. In a quest to design oligodeoxynucleotides (ODNs) which are able to specifically bid and inactivate the mRNA of a gene, it is necessary to fulfill two criteria: 1) increase binding affinity between the ODN and the target RNA and 2) increase the ODN's resistance to nuclease degradation. An ODN with an aminopropyl modification at the 2' position of its ribose has emerged as the most successful candidate at fulfilling both criteria. It is the most nuclease resistant modification known to date. We were interested in explaining how this modification is able to circumvent degradation by nucleases. A dodecamer containing a single 2'-O-aminopropyl modified nucleotide was crystallized and the structure was solved to a resolution of 1.6 A. In an attempt to explain the nuclease resistance, the crystal coordinates were modeled into the active exonuclease site of DNA polymerase I. We propose the

  17. RESISTIVITIES AND BAND STRUCTURES OF ALKALINE-EARTH-PNICTIDE SYSTEMS

    NARCIS (Netherlands)

    XU, R; DEGROOT, RA; VANDERLUGT, W

    1993-01-01

    The electrical resistivities p of the liquid Sr-Bi and Sr-Sb alloys have been determined for compositions covering the whole concentration range. Plotted as a function of composition the results resemble those obtained previously for Mg-Bi by other authors. There is a very sharp resistivity maximum

  18. The Structure of Fitness Landscapes in Antibiotic-Resistant Bacteria

    Science.gov (United States)

    Deris, Barrett; Kim, Minsu; Zhang, Zhongge; Okano, Hiroyuki; Hermsen, Rutger; Gore, Jeff; Hwa, Terence

    2014-03-01

    To predict the emergence of antibiotic resistance, quantitative relations must be established between the fitness of drug-resistant organisms and the molecular mechanisms conferring resistance. We have investigated E. coli strains expressing resistance to translation-inhibiting antibiotics. We show that resistance expression and drug inhibition are linked in a positive feedback loop arising from an innate, global effect of drug-inhibited growth on gene expression. This feedback leads generically to plateau-shaped fitness landscapes and concomitantly, for strains expressing at least moderate degrees of drug resistance, gives rise to an abrupt drop in growth rates of cultures at threshold drug concentrations. A simple quantitative model of bacterial growth based on this innate feedback accurately predicts experimental observations without ad hoc parameter fitting. We describe how drug-inhibited growth rate and the threshold drug concentration (the minimum inhibitory concentration, or MIC) depend on the few biochemical parameters that characterize the molecular details of growth inhibition and drug resistance (e.g., the drug-target dissociation constant). And finally, we discuss how these parameters can shape fitness landscapes to determine evolutionary dynamics and evolvability.

  19. Meurigite, a new fibrous iron phosphate resembling kidwellite

    Science.gov (United States)

    Birch, W.D.; Pring, A.; Self, P.G.; Gibbs, R.B.; Keck, E.; Jensen, M.C.; Foord, E.E.

    1996-01-01

    Meurigite is a new hydrated potassium iron phosphate related to kidwellite and with structural similarities to other late-stage fibrous ferric phosphate species. It has been found at four localities so far - the Santa Rita mine, New Mexico, U.S.A.; the Hagendorf-Sud pegmatite in Bavaria, Germany; granite pegmatite veins at Wycheproof, Victoria. Australia; and at the Gold Quarry Mine, Nevada, U.S.A. The Santa Rita mine is the designated type locality. Meurigite occurs as tabular, elongated crystals forming spherical and hemispherical clusters and drusy coatings. The colour ranges from creamy white to pale yellow and yellowish brown. At the type locality, the hemispheres may reach 2 mm across, but the maximum diameter reached in the other occurrences is usually less than 0.5 mm. A wide variety of secondary phosphate minerals accompanies meurigite at each locality, with dufrenite, cyrilovite. beraunite, rockbridgeite and leucophosphite amongst the most common. Vanadates and uranates occur with meurigite at the Gold Quarry mine. Electron microprobe analysis and separate determination of H2O and CO2 on meurigite from the type locality gave a composition for which several empirical formulae could be calculated. The preferred formula, obtained on the basis of 35 oxygen atoms, is (K0.85Na0.03)??0.88(Fe7.013+Al0.16Cu0.02)??7.19 (PO4)5.11(CO3)0.20(OH) 6.7??7-7.25H2O, which simplifies to KFe73+(PO4)5(OH) 7??8H2O. Qualitative analyses only were obtained for meurigite from the other localities, due to the softness and openness of the aggregates. Because of the fibrous nature of meurigite, it was not possible to determine the crystal structure, hence the exact stoichiometry remains uncertain. The lustre of meurigite varies from vitreous to waxy for the Santa Rita mine mineral, to silky for the more open sprays and internal surfaces elsewhere. The streak is very pale yellow to cream and the estimated Mohs hardness is about 3. Cleavage is perfect on {001] and fragments from the

  20. Microstructure of cotton fibrous assemblies based on computed tomography

    Science.gov (United States)

    Jing, Hui; Yu, Weidong

    2017-12-01

    This paper describes for the first time the analysis of inner microstructure of cotton fibrous assemblies using computed tomography. Microstructure parameters such as packing density, fractal dimension as well as porosity including open porosity, closed porosity and total porosity are calculated based on 2D data from computed tomography. Values of packing density and fractal dimension are stable in random oriented fibrous assemblies, and there exists a satisfactory approximate linear relationship between them. Moreover, poles analysis indicates that porosity represents the tightness of fibrous assemblies and open poles are main existence.

  1. Solitary fibrous tumor of the orbit with intracranial involvement.

    Science.gov (United States)

    Young, Thomas K; Hardy, Thomas G

    2011-01-01

    Solitary fibrous tumor of the orbit is a rare neoplasm that often follows a benign course. Additional involvement beyond the orbit is even rarer, having only been reported in 2 cases previously. The authors describe a 62-year-old patient with a primarily intracranial lesion including orbital extension which was debulked and initially diagnosed as meningioma. Two recurrences 3 and 4 years later disclosed a solitary fibrous tumor, with the initial histopathology being revised to the same diagnosis. This rare presentation of an orbital solitary fibrous tumor highlights the surgical challenge faced when the tumor straddles the cranio-orbital junction and demonstrates the potential for rapid regrowth after incomplete excision.

  2. CT features of fibrous dysplasia of the temporal bone

    International Nuclear Information System (INIS)

    Charrada-Ben Farhat, L.; Bourkhis, S.; Ben Yaacoub, I.; Dali, N.; Askri, A.; Hendaoui, L.

    2006-01-01

    Fibrous dysplasia is characterized by a progressive replacement of normal bone elements by fibrous tissue. The temporal bone is rarely involved. In this location, complications such as facial deformity, conductive hearing loss and facial peripheral neural involvement can occur. Positive diagnosis can be established with computerized tomography which also enables assessment of extension and detection of complications. We report a case of a 27-year-old man with extensive fibrous dysplasia of the right temporal bone presenting with conductive hearing loss secondary to progressive stenosis of the external auditory canal. Computerized tomography of the temporal region was performed. (authors)

  3. Solidification structure and abrasion resistance of high chromium white irons

    Science.gov (United States)

    Doğan, Ö. N.; Hawk, J. A.; Laird, G.

    1997-06-01

    Superior abrasive wear resistance, combined with relatively low production costs, makes high Cr white cast irons (WCIs) particularly attractive for applications in the grinding, milling, and pumping apparatus used to process hard materials. Hypoeutectic, eutectic, and hypereutectic cast iron compositions, containing either 15 or 26 wt pct chromium, were studied with respect to the macrostructural transitions of the castings, solidification paths, and resulting microstructures when poured with varying superheats. Completely equiaxed macrostructures were produced in thick section castings with slightly hypereutectic compositions. High-stress abrasive wear tests were then performed on the various alloys to examine the influence of both macrostructure and microstructure on wear resistance. Results indicated that the alloys with a primarily austenitic matrix had a higher abrasion resistance than similar alloys with a pearlitic/bainitic matrix. Improvement in abrasion resistance was partially attributed to the ability of the austenite to transform to martensite at the wear surface during the abrasion process.

  4. Genetic structure and evolved malaria resistance in Hawaiian honeycreepers

    Science.gov (United States)

    Foster, J.T.; Woodworth, B.L.; Eggert, L.E.; Hart, P.J.; Palmer, D.; Duffy, D.C.; Fleischer, R.C.

    2007-01-01

    Infectious diseases now threaten wildlife populations worldwide but population recovery following local extinction has rarely been observed. In such a case, do resistant individuals recolonize from a central remnant population, or do they spread from small, perhaps overlooked, populations of resistant individuals? Introduced avian malaria (Plasmodium relictum) has devastated low-elevation populations of native birds in Hawaii, but at least one species (Hawaii amakihi, Hemignathus virens) that was greatly reduced at elevations below about 1000 m tolerates malaria and has initiated a remarkable and rapid recovery. We assessed mitochondrial and nuclear DNA markers from amakihi and two other Hawaiian honeycreepers, apapane (Himatione sanguinea) and iiwi (Vestiaria coccinea), at nine primary study sites from 2001 to 2003 to determine the source of re-establishing birds. In addition, we obtained sequences from tissue from amakihi museum study skins (1898 and 1948-49) to assess temporal changes in allele distributions. We found that amakihi in lowland areas are, and have historically been, differentiated from birds at high elevations and had unique alleles retained through time; that is, their genetic signature was not a subset of the genetic variation at higher elevations. We suggest that high disease pressure rapidly selected for resistance to malaria at low elevation, leaving small pockets of resistant birds, and this resistance spread outward from the scattered remnant populations. Low-elevation amakihi are currently isolated from higher elevations (> 1000 m) where disease emergence and transmission rates appear to vary seasonally and annually. In contrast to results from amakihi, no genetic differentiation between elevations was found in apapane and iiwi, indicating that slight variation in genetic or life-history attributes can determine disease resistance and population recovery. Determining the conditions that allow for the development of resistance to disease is

  5. Structural studies of thermally stable, combustion-resistant polymer composites

    OpenAIRE

    Smith, G.N.; Hallett, J.E.; Joseph, P.; Tretsiakova-McNally, S.; Zhang, T.; Blum, F.D.; Eastoe, J.

    2017-01-01

    Composites of the industrially important polymer, poly(methyl methacrylate) (PMMA), were prepared by free-radical polymerization of MMA with varying amounts (1–30 wt. %) of sodium dioctylsulfosuccinate (Aerosol OT or AOT) surfactant added to the reaction mixture. The composites with AOT incorporated show enhanced resistance to thermal degradation compared to pure PMMA homopolymer, and micro-cone combustion calorimetry measurements also show that the composites are combustion-resistant. The ph...

  6. Structure of the Scientific Community Modelling the Evolution of Resistance

    OpenAIRE

    2007-01-01

    Faced with the recurrent evolution of resistance to pesticides and drugs, the scientific community has developed theoretical models aimed at identifying the main factors of this evolution and predicting the efficiency of resistance management strategies. The evolutionary forces considered by these models are generally similar for viruses, bacteria, fungi, plants or arthropods facing drugs or pesticides, so interaction between scientists working on different biological organisms would be expec...

  7. Direct measurement of graphene contact resistivity to pre-deposited metal in buried contact test structure

    KAUST Repository

    Qaisi, Ramy M.

    2013-08-01

    We demonstrate a buried contact based novel test structure for direct contact resistivity measurement of graphene-metal interfaces. We also observe excellent contact resistivity 1 μO-cm2 without any additional surface modification suggesting that the intrinsic Au-graphene contact is sufficient for achieving devices with low contact resistance. The chemical mechanical polishing less test structure and data described herein highlights an ideal methodology for systematic screening and engineering of graphene-metal contact resistivity to enable low power high speed carbon electronics. © 2013 IEEE.

  8. STRUCTURAL AND TECHNOLOGICAL PARAMETERS AFFECTING THE BIPOLAR STATIC INDUCTION TRANSISTOR (BSIT RESISTANCE

    Directory of Open Access Journals (Sweden)

    T. A. Ismailov

    2016-01-01

    Full Text Available Aim. The aim of the study is to determine the impact of structural and technological parameters on the resistance of the bipolar static induction transistor.Methods. The paper provides a comparative analysis of the advantages of bipolar static induction transistor compared to the bipolar power transistors, MOSFETs and insulated-gate bipolar transistor (IGBT. Considered are structural and technological parameters that influence the resistance of BSIT-transistor.Result. As a result of experimental study on silicon substrates were formed test prototypes of BSIT transistor structure, are presented calculation and experimental works. Obtained are the resistance dependencies of the transistor cell on the thickness of the epitaxial film; the resistance dependencies of BSIT transistor cell on the effective gate length for different values of the impurity concentration in the epitaxial film; dependencies resistance of the transistor cell on the gate length at different values of the epitaxial film thickness; the resistance dependencies of BSIT transistor cell on the distance between the mask for the p-region and the gate; dependencies on the multiplication the cell resistance by its area on the gate length.Conclusion. When increasing the gate length (Lk and the mask length for the p-region (lp + in the transistor structure, the resistance decreases and the dependence of multiplication of the cell resistance by its area Q on the gate length has this case the minimum.

  9. Structure of the scientific community modelling the evolution of resistance.

    Science.gov (United States)

    2007-12-05

    Faced with the recurrent evolution of resistance to pesticides and drugs, the scientific community has developed theoretical models aimed at identifying the main factors of this evolution and predicting the efficiency of resistance management strategies. The evolutionary forces considered by these models are generally similar for viruses, bacteria, fungi, plants or arthropods facing drugs or pesticides, so interaction between scientists working on different biological organisms would be expected. We tested this by analysing co-authorship and co-citation networks using a database of 187 articles published from 1977 to 2006 concerning models of resistance evolution to all major classes of pesticides and drugs. These analyses identified two main groups. One group, led by ecologists or agronomists, is interested in agricultural crop or stock pests and diseases. It mainly uses a population genetics approach to model the evolution of resistance to insecticidal proteins, insecticides, herbicides, antihelminthic drugs and miticides. By contrast, the other group, led by medical scientists, is interested in human parasites and mostly uses epidemiological models to study the evolution of resistance to antibiotic and antiviral drugs. Our analyses suggested that there is also a small scientific group focusing on resistance to antimalaria drugs, and which is only poorly connected with the two larger groups. The analysis of cited references indicates that each of the two large communities publishes its research in a different set of literature and has its own keystone references: citations with a large impact in one group are almost never cited by the other. We fear the lack of exchange between the two communities might slow progress concerning resistance evolution which is currently a major issue for society.

  10. Improved lifetime of new fibrous carbon/ceramic composites

    Science.gov (United States)

    Gumula, Teresa

    2018-03-01

    New carbon/ceramic composites have been synthesized from low-cost phenol-formaldehyde resin and polysiloxane preceram. A reference carbon composite reinforced with carbon fibre (CC composite) is obtained in first place from a carbon fibre roving impregnated with a solution of phenol-formaldehyde resin in isopropyl alcohol. To obtain fibrous carbon/ceramic composites the CC perform is impregnated with polymethylphenylsiloxane polymer and then a thermal treatment in an inert atmosphere is applied. Depending on the temperature of this process, the resulting ceramics can be silicon carbide (SiC) or silicon oxycarbide (SiCO). Three representative samples, named CC/SiCO( a) (obtained at 1000 °C), CC/SiCO( b) (1500 °C) and CC/SiC (1700 °C), have been tested for fatigue behaviour and oxidation resistance. The value of the Young's modulus remains constant in fatigue tests done in flexion mode for the three new composites during a high number of cycles until sudden degradation begins. This is an unusual and advantageous characteristic for this type of materials and results in the absence of delamination during the measurements. In contrast, the CC reference composite shows a progressive degradation of the Young's modulus accompanied by delamination. SEM micrographs revealed that the formation of filaments of submicrometer diameter during the heat treatment can be responsible for the improved behaviour of these composites. The CC/SiC composite shows the best oxidation resistance among the three types of composites, with a 44% mass loss after 100 h of oxidation.

  11. Resistance and Security Index of Networks: Structural Information Perspective of Network Security

    Science.gov (United States)

    Li, Angsheng; Hu, Qifu; Liu, Jun; Pan, Yicheng

    2016-01-01

    Recently, Li and Pan defined the metric of the K-dimensional structure entropy of a structured noisy dataset G to be the information that controls the formation of the K-dimensional structure of G that is evolved by the rules, order and laws of G, excluding the random variations that occur in G. Here, we propose the notion of resistance of networks based on the one- and two-dimensional structural information of graphs. Given a graph G, we define the resistance of G, written , as the greatest overall number of bits required to determine the code of the module that is accessible via random walks with stationary distribution in G, from which the random walks cannot escape. We show that the resistance of networks follows the resistance law of networks, that is, for a network G, the resistance of G is , where and are the one- and two-dimensional structure entropies of G, respectively. Based on the resistance law, we define the security index of a network G to be the normalised resistance of G, that is, . We show that the resistance and security index are both well-defined measures for the security of the networks. PMID:27255783

  12. Resistance and Security Index of Networks: Structural Information Perspective of Network Security.

    Science.gov (United States)

    Li, Angsheng; Hu, Qifu; Liu, Jun; Pan, Yicheng

    2016-06-03

    Recently, Li and Pan defined the metric of the K-dimensional structure entropy of a structured noisy dataset G to be the information that controls the formation of the K-dimensional structure of G that is evolved by the rules, order and laws of G, excluding the random variations that occur in G. Here, we propose the notion of resistance of networks based on the one- and two-dimensional structural information of graphs. Given a graph G, we define the resistance of G, written , as the greatest overall number of bits required to determine the code of the module that is accessible via random walks with stationary distribution in G, from which the random walks cannot escape. We show that the resistance of networks follows the resistance law of networks, that is, for a network G, the resistance of G is , where and are the one- and two-dimensional structure entropies of G, respectively. Based on the resistance law, we define the security index of a network G to be the normalised resistance of G, that is, . We show that the resistance and security index are both well-defined measures for the security of the networks.

  13. Electrospun Poly(lactic acid)-Based Fibrous Nanocomposite Reinforced by Cellulose Nanocrystals: Impact of Fiber Uniaxial Alignment on Microstructure and Mechanical Properties.

    Science.gov (United States)

    Huan, Siqi; Liu, Guoxiang; Cheng, Wanli; Han, Guangping; Bai, Long

    2018-03-12

    Uniform poly(lactic acid)/cellulose nanocrystal (PLA/CNC) fibrous mats composed of either random or aligned fibers reinforced with up to 20 wt % CNCs were successfully produced by two different electrospinning processes. Various concentrations of CNCs could be stably dispersed in PLA solution prior to fiber manufacture. The microstructure of produced fibrous mats, regardless of random or aligned orientation, was transformed from smooth to nanoporous surface by changing CNC loading levels. Aligning process through secondary stretching during high-speed collection can also affect the porous structure of fibers. With the same CNC loading, fibrous mats produced with aligned fibers had higher degree of crystallinity than that of fibers with random structure. The thermal properties and mechanical performances of PLA/CNC fibrous mats can be enhanced, showing better enhancement effect of aligned fibrous structure. This results from a synergistic effect of the increased crystallinity of fibers, the efficient stress transfer from PLA to CNCs, and the ordered arrangement of electrospun fibers in the mats. This research paves a way for developing an electrospinning system that can manufacture high-performance CNC-enhanced PLA fibrous nanocomposites.

  14. Decortication of fibrous dysplasia of the maxillary sinus.

    Science.gov (United States)

    Lee, Yoon Ho; Hwang, Kun

    2011-01-01

    We present 3 cases of fibrous dysplasia of the maxillary sinus that were treated by decortication through the anterior wall of the maxilla. The thickened anterior wall of the maxilla and the zygoma were contoured into normal shape with a bur, and a 2 × 2-cm window was made below the infraorbital foramen using a reciprocating saw. The removed piece of bone was 3 to 5 mm thick. All abnormal fibrous tissues in the maxillary sinus were extirpated by drilling through the window until the sinus cavity was clear. The preserved bone plate was restored in place to close the window of the maxillary anterior wall and fixed with miniplates. Three patients were treated by means of such internal decompression method. No overgrowth or disfigurement of the facial bone was appreciated 14 to 51 months postoperatively. We contend that internal decortication of fibrous dysplasia through a window in the anterior wall is effective to minimize external expansion of fibrous dysplasia.

  15. Ocular malignant fibrous histiocytoma: clinical and histopathological characteristics.

    OpenAIRE

    Krishnan, M M; Kawatra, V K; Ratnakar, C; Rao, V A; Veliath, A J

    1987-01-01

    A rare case of malignant fibrous histiocytoma involving the whole eye is reported in an Oriental 60-year-old man. Six months' follow-up after exenteration did not show any evidence of local recurrence or distant metastases.

  16. Ehlers-Danlos syndrome with monostotic fibrous dysplasia

    Directory of Open Access Journals (Sweden)

    Rao A

    1979-01-01

    Full Text Available An unusual case of Ehlers-Danlos syndrome with monostotic fibrous dysplasia of the humorus is presented. The other orthopae-dic manifestations, its complications and associated features are re-viewed and summarised.

  17. MRI of fibrous cortical defect and non-ossifying fibroma

    Energy Technology Data Exchange (ETDEWEB)

    Mishima, Yoshiko; Aoki, Takatoshi; Watanabe, Hideyuki; Nakata, Hajime; Hashimoto, Hiroshi; Nakamura, Toshitaka [Univ. of Occupational and Environmental Health, Kitakyushu, Fukuoka (Japan). School of Medicine

    1999-02-01

    Fibrous cortical defect and non-ossifying fibroma are the benign fibrous lesions of bone commonly involving children. Their diagnosis is usually done with radiography, and MR examinations are rarely performed. We evaluated MRI findings of 11 lesions in 10 cases of fibrous cortical defect and non-ossifying fibroma. Signal intensity of the lesions was varied and large lesions (2 cm<) tended to show heterogeneous signal intensity on both T1-weighted and T2-weighted images corresponding to a mixture of components including fibrous tissue, hemosiderin and foam cells. MRI helps to delineate the extent of the involved bone and to assess the various histological components of the lesions. However, their diagnosis is basically made on the radiographic findings and the role of MRI is limited. (author)

  18. Craniofacial fibrous dysplasia surgery: a functional approach.

    Science.gov (United States)

    Béquignon, E; Cardinne, C; Lachiver, X; Wagner, I; Chabolle, F; Baujat, B

    2013-09-01

    Craniofacial fibrous dysplasia has not only esthetic but functional impact. Surgery is controversial, ranging from conservative to radical. It involves elevated hemorrhage risk, and should be progressive, based on an individual risk/benefit analysis with the aim of improving quality of life. Three patients (one male, two female; mean age, 35 years) with evolutive orbital-temporal maxillary dysplasia were treated between 2008 and 2009 in our department. All showed exophthalmia and nasal obstruction. In one patient, symptomatology was aggravated by a frontal sinus cyst within the dysplasia. Another had associated auditory canal obstruction inducing recurrent external otitis. Optic nerve decompression was achieved on a combined coronal and endonasal approach, assisted by neuronavigation. Complementary remodelling resection, dacryocystorhinostomy and internal optic nerve decompression were performed. Functional results showed 70 % improvement on a subjective scale for eye tension and nasal obstruction. Surgery was feasible in all patients, with no complications. Current surgical management allies esthetic and functional concerns. Remodeling resection is the reference technique. The coronal approach is a good primary option for optic nerve decompression. Endonasal surgery with neuronavigation improves nasal ventilation and lacrimal canal permeability. Copyright © 2012 Elsevier Masson SAS. All rights reserved.

  19. Treating Fibrous Insulation to Reduce Thermal Conductivity

    Science.gov (United States)

    Zinn, Alfred; Tarkanian, Ryan

    2009-01-01

    A chemical treatment reduces the convective and radiative contributions to the effective thermal conductivity of porous fibrous thermal-insulation tile. The net effect of the treatment is to coat the surfaces of fibers with a mixture of transition-metal oxides (TMOs) without filling the pores. The TMO coats reduce the cross-sectional areas available for convection while absorbing and scattering thermal radiation in the pores, thereby rendering the tile largely opaque to thermal radiation. The treatment involves a sol-gel process: A solution containing a mixture of transition-metal-oxide-precursor salts plus a gelling agent (e.g., tetraethylorthosilicate) is partially cured, then, before it visibly gels, is used to impregnate the tile. The solution in the tile is gelled, then dried, and then the tile is fired to convert the precursor salts to the desired mixed TMO phases. The amounts of the various TMOs ultimately incorporated into the tile can be tailored via the concentrations of salts in the solution, and the impregnation depth can be tailored via the viscosity of the solution and/or the volume of the solution relative to that of the tile. The amounts of the TMOs determine the absorption and scattering spectra.

  20. Postheated Model of Confined High Strength Fibrous Concrete

    Directory of Open Access Journals (Sweden)

    Kaleem A. Zaidi

    2016-01-01

    Full Text Available HSC normally suffers from low stiffness and poor strain capacity after exposure to high temperature. High strength confined fibrous concrete (HSCFC is being used in industrial structures and other high rise buildings that may be subjected to high temperature during operation or in case of an accidental fire. The proper understanding of the effect of elevated temperature on the stress-strain relationship of HSCFC is necessary for the assessment of structural safety. Further stress-strain model of HSCFC after exposure to high temperature is scarce in literature. Experimental results are used to generate the complete stress-strain curves of HSCFC after exposure to high temperature in compression. The variation in concrete mixes was achieved by varying the types of fibre, volume fraction of fibres, and temperature of exposure from ambient to 800°C. The degree of confinement was kept constant in all the specimens. A comparative assessment of different models on the high strength confined concrete was also conducted at different temperature for the accuracy of proposed model. The proposed empirical stress-strain equations are suitable for both high strength confined concrete and HSCFC after exposure to high temperature in compression. The predictions were found to be in good agreement and well fit with experimental results.

  1. Individual domain wall resistance in submicron ferromagnetic structures.

    Science.gov (United States)

    Danneau, R; Warin, P; Attané, J P; Petej, I; Beigné, C; Fermon, C; Klein, O; Marty, A; Ott, F; Samson, Y; Viret, M

    2002-04-15

    The resistance generated by individual domain walls is measured in a FePd nanostructure. Combining transport and magnetic imaging measurements, the intrinsic domain wall resistance is quantified. It is found positive and of a magnitude consistent with that predicted by models based on spin scattering effects within the walls. This magnetoresistance at a nanometer scale allows a direct counting of the number of walls inside the nanostructure. The effect is then used to measure changes in the magnetic configuration of submicron stripes under application of a magnetic field.

  2. Structural insights into the quinolone resistance mechanism of Mycobacterium tuberculosis DNA gyrase.

    OpenAIRE

    Piton , Jérémie; Petrella , Stéphanie; Delarue , Marc; André-Leroux , Gwénaëlle; Jarlier , Vincent; Aubry , Alexandra; Mayer , Claudine

    2010-01-01

    International audience; Mycobacterium tuberculosis DNA gyrase, an indispensable nanomachine involved in the regulation of DNA topology, is the only type II topoisomerase present in this organism and is hence the sole target for quinolone action, a crucial drug active against multidrug-resistant tuberculosis. To understand at an atomic level the quinolone resistance mechanism, which emerges in extensively drug resistant tuberculosis, we performed combined functional, biophysical and structural...

  3. [Fibrous dysplasia of the scull discovered accidently on CT from different indication].

    Science.gov (United States)

    Sztuk, Stanisław; Jaworek, Joanna Karolina; Bryll, Amira; Nardzewska-Szczepanik, Monika; Urbanik, Andrzej

    2010-01-01

    Fibrous dysplasia (dysplasia fibrosa -DF) is a local disorder of spongy bone structure caused by local pathological metabolism. Transformation of trabecular bony structure into connective tissue takes place. Inside the transformed bone scattered connective tissue elements, cartilaginous elements and pathological density are found. The disease proliferates either in the medullary bone or in subperiosteal region, and the development of fibrous tissue causes bone expansion with thinning of overlying cortex. The radiological appearance depends on the stage of the disease. The margins of the lesions are usually obscured and gradually turn into pathological tissue of trabeculated appearance. The aim of the study is to demonstrate fibrous dysplasia that is accidentally found during radiological diagnostics of facial skeleton and stomatological disease, and to describe radiological appearance of the pathological lesions. The material included 23 patients (9 males, 14 females), of 24 to 64 years of age, that were directed for the diagnostics of facial skeleton and stomatological disease with the use of multislice computer tomography, because of clinically diagnosed pathologies in the nasal sinuses, temporomandibular joints, pathologies of the mandible and maxillary, and before treatment with prosthetic implants. All the presented fibrous dysplasia cases were diagnosed during the performance of the above examinations. The examinations were performed by the use of spiral CT (Siemens Somatom Sensation 10) with standard parameters. The range of the examination included the nasal sinuses, facial skeleton or the whole scull-configuration of the detectors 10 x 0.75 mm, slice thickness 1 mm, reconstruction gap 0.7 mm, kernel H60s for osseous structure evaluation, and slice thickness 1, 4 do 4 mm, reconstruction gap 4 mm, kernel H31s for soft tissue evaluation. The obtained results were presented sented in the form of figures. In the analyzed material 23 cases of scull fibrous

  4. Welcome to Fibers—A New Open Access Journal for Fibrous Material Science

    Directory of Open Access Journals (Sweden)

    Stephen C. Bondy

    2012-08-01

    Full Text Available Fibers are materials in the form of elongated threads. They can possess elastic features that are relevant to the integrity and bonding of cells. These features also give man-made fibers a wide range of applications. The large ratio of length to width (aspect ratio, which defines fibers, strongly influences their physical and chemical properties. This quality gives them a relatively large surface area, which can lead to powerful tensile and absorptive characteristics, which are remarkably different from, and cannot be predicted by study of the non-fibrous parent materials. An example of this is asbestos, where the toxicity of the material is heavily influenced by its structural anatomy. Distinctive chemical processes can take place on fibrous surfaces that may themselves seem to be chemically inert. Certain commonalities result from the distinctive geometry of fibers, and lie behind the apparently great diversity of fiber types and materials. [...

  5. Ground-glass pattern fibrous dysplasia of frontal sinus.

    Science.gov (United States)

    Chourmouzi, D; Psoma, E; Drevelegas, A

    2013-01-01

    The case of a 5-year-old boy with ground-glass pattern craniofacial fibrous dysplasia (FD) presenting with progressive swelling in the right frontal region is reported. The imaging findings with computed tomography and magnetic resonance imaging (MRI) findings are presented. The differential diagnosis with inspissated mucocele is discussed as well. Fibrous tissue could be hypo dense on CT. Post-contrast enhancement of the lesion on MRI is the key for diagnosis.

  6. Computed tomographic features of fibrous dysplasia of maxillofacial region

    OpenAIRE

    Sontakke, Subodh Arun; Karjodkar, Freny R; Umarji, Hemant R

    2011-01-01

    Purpose This study was to find the computed tomographic features of fibrous dysplasia of the maxillofacial region. Materials and Methods All eight cases included in the study reported either to Government Dental College and Hospital or Nair Hospital Dental College, Mumbai between 2003 and 2009. The patients were prescribed computed tomogram in addition to conventional radiographs of maxillofacial region which were studied for characteristic features of fibrous dysplasia. The diagnosis of fibr...

  7. Chondrosarcoma occurring in a patient with polyostotic fibrous dysplasia

    Energy Technology Data Exchange (ETDEWEB)

    De Smet, A.A.; Travers, H.; Neff, J.R.

    1981-12-01

    A 36-year-old white man with polyostotic fibrous dysplasia was found to have a high-grade chondrosarcoma arising from the left ilium. Although a left hemipelvectomy was performed, the patient subsequently developed sacral and pulmonary metastases and succumbed to his disease. This patient represents the first documented example of an unequivocally high-grade chondrosarcoma arising in an area of fibrous dysplasia without prior irradiation.

  8. Fibrous epulis associated with impacted lower right third molar

    Directory of Open Access Journals (Sweden)

    Ni Putu Mira Sumarta

    2009-12-01

    Full Text Available Background: Epulis or epulides are lesions associated with gingival tissues. Fibrous epulis is a type of hyperplastic fibrous tissue mass located at the gingival which is slow growing, painless, having same color as the oral mucosa and firm on palpation. Anterior regions of the oral cavity are the frequently affected sites as these areas are more prone to be affected by calculus deposition and poor plaque control due to frequent teeth malposition. Removal of any irritating factors and excision of the lesion are the usual treatments. Purpose: This case report presents a rare case of fibrous epulis which occurred in the posterior region of the oral cavity and associated with impacted lower third molar. Case: A case of fibrous epulis at the lower right third molar area of three months duration is presented. The mass was slow growing, painless and on examination it was a pedunculated mass overlying the unerupted lower right third molar, having same color with the oral mucosa and firm on palpation. Clinically, the lesion was diagnosed as fibrous epulis associated with impacted lower right third molar. Case management: The treatment were surgical excision of the epulis and removal of the lower right third molar. The histopathology result showed tissue with squamous epithelial lining, achanthotic fibrous connective tissue, mononuclear inflammatory cells and few capillaries without signs of malignancy. This is consistent with the diagnosis of fibrous epulis. Conclusion: Fibrous epulis, although frequently occurred at the anterior region of the oral cavity, may rarely grow at the area of lower third molar. This phenomenon supports the theory that epulis can grow on any surface of oral mucous membrane as long as local irritants are present.

  9. Localized fibrous mesothelioma of the liver: a case report

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Young Hwan; Lee, Moon Gyu; Weon, Young Cheol; Lee, Seung Gyu; Kim, Yoon Jeong; Lee, In Chul; Auh, Yong Ho [Asan Medical Center, University of Ulsan College of Medicine, Seoul (Korea, Republic of)

    1995-10-15

    Localized fibrous mesothelioma of the liver is very rare benign tumor. It usually manifest large palpable hepatic mass in right upper quadrant area, and the prognosis is excellent by surgical resection. Contrast enhanced CT scan shows well defined hyperattenuating mass and celiac angiogram shows hypervascular mass. Recently we experienced 1 case of localized fibrous mesothelioma of the liver, and we report CT and angiographic findings of this tumor.

  10. Synthesis of fibrous and non-fibrous mesoporous silica magnetic yolk-shell microspheres as recyclable supports for immobilization of Candida rugosa lipase.

    Science.gov (United States)

    Ali, Zafar; Tian, Lei; Zhang, Baoliang; Ali, Nisar; Khan, Muhammad; Zhang, Qiuyu

    2017-08-01

    The mesoporous yolk-shell nanoparticles (MYSNs), with a movable Fe 3 O 4 core inside the hollow capsules, with two different morphologies (1) Fe 3 O 4 @SiO 2 @hollow@fibrous SiO 2 (Yolk Shell-1) (2) Fe 3 O 4 @SiO 2 @hollow@mesoporousSiO 2 (Yolk Shell-2) were fabricated as carriers for Candida rugosa lipase (CRL) immobilization, through a template-assistant selectively etching method. Firstly the hydrophilic Fe 3 O 4 nanoparticles were synthesized according to the solvothermal method. Then, SiO 2 shell was coated on the Fe 3 O 4 nanoparticle surface by a sol-gel reaction. Subsequently, the resorcinol farmaldehyde (RF) shell was covered on the surface of as-prepared Fe 3 O 4 @SiO 2 composites and sandwiched Fe 3 O 4 @SiO 2 @RF composites were formed, which were finally provided with mesoporous fibrous (KCC) in the Yolk Shell-1 and mesoporous Silica in the Yolk Shell-2(Non fibrous). After selectively etching CTAB and the middle RF layer, the two kinds of yolk/shells composites were obtained. By utilization of their large and open mesopores (20-50nm) with good surface area (457.78-625.54m 2 /g,) CRL was immobilized after amino functionalization using glutaraldehyde as a linker. The ICRL on Y.S-1, Y.S-2 showed good loading (797-501mg/g) and enzyme activity of (1503-837U/g) respectively. Thermal stability, resistance to pH, recycling and storage capacity were improved as compare to free lipase. Copyright © 2017. Published by Elsevier Inc.

  11. [Fronto-ethmoidal fibrous dysplasia: a case-report].

    Science.gov (United States)

    Hoareau-Gruchet, F; Nils, M; Spinato, L; Rabeyrin, M; Righini, C A

    2012-01-01

    Fibrous dysplasia is a congenital bone disease, where normal bone is replaced by a fibrous-like tissue with immature osteogenesis. The cephalic extremity is affected in one out of three cases. The aim of this study was to describe a case of fibrous dysplasia and review workup and management of this pathology. We reviewed relevant publications using the Medline database and presented a case of isolated paranasal sinus fibrous dysplasia to illustrate this disease. The clinical onset was headache and left palpebral oedema in a twelve-year old. Imaging showed a left fronto-ethmoidal bone lesion with epidural empyema. No other radiological anomaly or phosphor-calcic disorder was present. The clinical course was positive using intravenous antibiotics, with a two-year follow-up. Fibrous dysplasia is diagnosed using CT-scan, without the need for histologic confirmation in most cases. Initial workup includes axial skeleton X-rays and hormonal dosages. The efficiency of biphosphonates drugs has significally reduced the number of surgical procedures. Fibrous dysplasia is often a multifocal disease and should be treated medically first. Management requires a multi-disciplinary team.

  12. Structural Characterization of Highly Corrosion-resistant Steel

    Czech Academy of Sciences Publication Activity Database

    Lančok, Adriana; Kmječ, T.; Štefánik, M.; Sklenka, L.; Miglierini, M.

    2015-01-01

    Roč. 88, č. 4 (2015), s. 355-361 ISSN 0011-1643 R&D Projects: GA ČR(CZ) GA14-12449S Institutional support: RVO:61388980 Keywords : Mossbauer spectroscopy * corrosion-resistant steel * LC200 * CEMS Subject RIV: CA - Inorganic Chemistry Impact factor: 0.732, year: 2015

  13. Unique Structural Modifications Are Present in the Lipopolysaccharide from Colistin-Resistant Strains of Acinetobacter baumannii

    Science.gov (United States)

    2013-10-01

    SECURITY CLASSIFICATION OF: Acinetobacter baumannii is a nosocomial opportunistic pathogen that can cause severe infections, including hospital-acquired...distribution is unlimited. Unique Structural Modifications Are Present in the Lipopolysaccharide from Colistin-Resistant Strains of Acinetobacter baumannii ...from Colistin-Resistant Strains of Acinetobacter baumannii Report Title Acinetobacter baumannii is a nosocomial opportunistic pathogen that can cause

  14. Deep Resistivity Structure of Mid Valley, Nevada Test Site, Nevada

    Science.gov (United States)

    Wallin, Erin L.; Rodriguez, Brian D.; Williams, Jackie M.

    2009-01-01

    The U.S. Department of Energy (DOE) and the National Nuclear Security Administration (NNSA) at their Nevada Site Office (NSO) are addressing ground-water contamination resulting from historical underground nuclear testing through the Environmental Management (EM) program and, in particular, the Underground Test Area (UGTA) project. From 1951 to 1992, 828 underground nuclear tests were conducted at the Nevada Test Site northwest of Las Vegas (DOE UGTA, 2003). Most of these tests were conducted hundreds of feet above the ground-water table; however, more than 200 of the tests were near, or within, the water table. This underground testing was limited to specific areas of the Nevada Test Site including Pahute Mesa, Rainier Mesa/Shoshone Mountain (RM-SM), Frenchman Flat, and Yucca Flat. One issue of concern is the nature of the somewhat poorly constrained pre-Tertiary geology and its effects on ground-water flow in the area subsequent to a nuclear test. Ground-water modelers would like to know more about the hydrostratigraphy and geologic structure to support a hydrostratigraphic framework model that is under development for the Rainier Mesa/Shoshone Mountain (RM-SM) Corrective Action Unit (CAU) (National Security Technologies, 2007). During 2003, the U.S. Geological Survey (USGS), in cooperation with the DOE and NNSA-NSO collected and processed data at the Nevada Test Site in and near Yucca Flat (YF) to help define the character, thickness, and lateral extent of the pre-Tertiary confining units. We collected 51 magnetotelluric (MT) and audio-magnetotelluric (AMT) stations for that research (Williams and others, 2005a, 2005b, 2005c, 2005d, 2005e, and 2005f). In early 2005 we extended that research with 26 additional MT data stations (Williams and others, 2006) located on and near Rainier Mesa and Shoshone Mountain (RM-SM). The new stations extended the area of the hydrogeologic study previously conducted in Yucca Flat, further refining what is known about the pre

  15. Structural design guidelines for concrete bridge decks reinforced with corrosion-resistant reinforcing bars.

    Science.gov (United States)

    2014-10-01

    This research program develops and validates structural design guidelines and details for concrete bridge decks with : corrosion-resistant reinforcing (CRR) bars. A two-phase experimental program was conducted where a control test set consistent : wi...

  16. Alkali corrosion resistant coatings and ceramic foams having superfine open cell structure and method of processing

    Science.gov (United States)

    Brown, Jr., Jesse J.; Hirschfeld, Deidre A.; Li, Tingkai

    1993-12-07

    Alkali corrosion resistant coatings and ceramic foams having superfine open cell structure are created using sol-gel processes. The processes have particular application in creating calcium magnesium zirconium phosphate, CMZP, coatings and foams.

  17. Microstructural and compositional features of the fibrous and hyaline cartilage on the medial tibial plateau imply a unique role for the hopping locomotion of kangaroo.

    Directory of Open Access Journals (Sweden)

    Bo He

    Full Text Available Hopping provides efficient and energy saving locomotion for kangaroos, but it results in great forces in the knee joints. A previous study has suggested that a unique fibrous cartilage in the central region of the tibial cartilage could serve to decrease the peak stresses generated within kangaroo tibiofemoral joints. However, the influences of the microstructure, composition and mechanical properties of the central fibrous and peripheral hyaline cartilage on the function of the knee joints are still to be defined. The present study showed that the fibrous cartilage was thicker and had a lower chondrocyte density than the hyaline cartilage. Despite having a higher PG content in the middle and deep zones, the fibrous cartilage had an inferior compressive strength compared to the peripheral hyaline cartilage. The fibrous cartilage had a complex three dimensional collagen meshwork with collagen bundles parallel to the surface in the superficial zone, and with collagen bundles both parallel and perpendicular to the surface in the middle and deep zones. The collagen in the hyaline cartilage displayed a typical Benninghoff structure, with collagen fibres parallel to the surface in the superficial zone and collagen fibres perpendicular to the surface in the deep zone. Elastin fibres were found throughout the entire tissue depth of the fibrous cartilage and displayed a similar alignment to the adjacent collagen bundles. In comparison, the elastin fibres in the hyaline cartilage were confined within the superficial zone. This study examined for the first time the fibrillary structure, PG content and compressive properties of the central fibrous cartilage pad and peripheral hyaline cartilage within the kangaroo medial tibial plateau. It provided insights into the microstructure and composition of the fibrous and peripheral hyaline cartilage in relation to the unique mechanical properties of the tissues to provide for the normal activities of kangaroos.

  18. TERT promoter mutations and prognosis in solitary fibrous tumor.

    Science.gov (United States)

    Bahrami, Armita; Lee, Seungjae; Schaefer, Inga-Marie; Boland, Jennifer M; Patton, Kurt T; Pounds, Stanley; Fletcher, Christopher D

    2016-12-01

    Solitary fibrous tumor is a mesenchymal neoplasm exhibiting a broad spectrum of biological behavior and harboring the NAB2-STAT6 fusion. Clinicopathologic parameters are currently used in risk-prediction models for solitary fibrous tumor, but the molecular determinants of malignancy in solitary fibrous tumors remain unknown. We proposed that the activation of telomere maintenance pathways confers a perpetual malignant phenotype to these tumors. Therefore, we investigated telomerase reverse transcriptase (TERT) reactivation induced by promoter mutations as a potential molecular mechanism for aggressive clinical behavior in solitary fibrous tumor. The retrospective study included tumor samples from 94 patients with solitary fibrous tumor (31 thoracic and 63 extra-thoracic). Follow-up information was available for 68 patients (median, 46 months). TERT promoter mutation analysis was performed by PCR and Sanger sequencing, and TERT mRNA expression was assessed by real-time quantitative reverse transcription PCR. Patients were stratified into clinicopathologic subgroups (high-risk (n=20), moderate-risk (n=28), and low-risk (n=46)) according to the risk-stratification model proposed by Demicco et al. TERT promoter mutations were identified in 26 of 94 (28%) solitary fibrous tumors: -124C>T in 23 tumors (88%), -124C>A in 1 tumor (4%), and -146C>T in 2 tumors (8%). Real-time quantitative reverse transcription PCR revealed that TERT mRNA expression was higher in all solitary fibrous tumors with the mutant TERT promoter than those with the wild-type TERT promoter. TERT promoter mutations were strongly associated with high-risk clinicopathologic characteristics and outcome. An adverse event (relapse, death) occurred in 16 of 68 (24%) patients, 12 with solitary fibrous tumors with TERT promoter mutations and 4 with the wild-type TERT promoter. TERT promoter mutations were strongly associated with older age (P=0.006), larger tumor size (P=0.000002), higher risk classifications

  19. Imaging features of intracranial solitary fibrous tumors

    International Nuclear Information System (INIS)

    Yu Shuilian; Man Yuping; Ma Longbai; Liu Ying; Wei Qiang; Zhu Youkai

    2012-01-01

    Objective: To summarize the imaging features of intracranial solitary fibrous tumors (ISFT). Methods: Ten patients with ISFT proven histopathologically were collected. Four cases had CT data and all cases had MR data. The imaging features and pathological results were retrospectively analyzed. Results: All cases were misdiagnosed as meningioma at pre-operation. All lesions arose from intracranial meninges including 5 lesions above the tentorium, 4 lesions beneath the tentorium and 1 lesion growing around the tentorium. The margins of all the masses were well defined, and 8 lesions presented multilobular shape. CT demonstrated hyerattenuated masses in all 4 lesions, smooth erosion of the basicranial skull in 1 lesion, and punctiform calcification of the capsule in 1 lesion. T 1 WI showed most lesions with isointense or slight hyperintense signals including homogeneous in 4 lesions and heterogeneous in 6 lesions. T 2 WI demonstrated isointense or slight hyperintense in 2 lesions, mixed hypointense and hyperintense signals in 4, cystic portion in 2, and two distinct portion of hyperintense and hypointense signal, so called 'yin-yang' pattern, in 2. Strong enhanced was found in all lesions, especially in 8 lesion with heterogeneous with the low T 2 signal. 'Dural tail' was found in 4 lesions. Conclusions: ISFI has some specific CT and MR features including heterogeneous signal intensity on T 2 WI, strong enhancement of areas with low T 2 signal intensity, slight or no 'dural tail', without skull thickening, and the typical 'yin-yang' pattern. (authors)

  20. Electrospun biomimetic fibrous scaffold from shape memory polymer of PDLLA-co-TMC for bone tissue engineering.

    Science.gov (United States)

    Bao, Min; Lou, Xiangxin; Zhou, Qihui; Dong, Wen; Yuan, Huihua; Zhang, Yanzhong

    2014-02-26

    Multifunctional fibrous scaffolds, which combine the capabilities of biomimicry to the native tissue architecture and shape memory effect (SME), are highly promising for the realization of functional tissue-engineered products with minimally invasive surgical implantation possibility. In this study, fibrous scaffolds of biodegradable poly(d,l-lactide-co-trimethylene carbonate) (denoted as PDLLA-co-TMC, or PLMC) with shape memory properties were fabricated by electrospinning. Morphology, thermal and mechanical properties as well as SME of the resultant fibrous structure were characterized using different techniques. And rat calvarial osteoblasts were cultured on the fibrous PLMC scaffolds to assess their suitability for bone tissue engineering. It is found that by varying the monomer ratio of DLLA:TMC from 5:5 to 9:1, fineness of the resultant PLMC fibers was attenuated from ca. 1500 down to 680 nm. This also allowed for readily modulating the glass transition temperature Tg (i.e., the switching temperature for actuating shape recovery) of the fibrous PLMC to fall between 19.2 and 44.2 °C, a temperature range relevant for biomedical applications in the human body. The PLMC fibers exhibited excellent shape memory properties with shape recovery ratios of Rr > 94% and shape fixity ratios of Rf > 98%, and macroscopically demonstrated a fast shape recovery (∼10 s at 39 °C) in the pre-deformed configurations. Biological assay results corroborated that the fibrous PLMC scaffolds were cytocompatible by supporting osteoblast adhesion and proliferation, and functionally promoted biomineralization-relevant alkaline phosphatase expression and mineral deposition. We envision the wide applicability of using the SME-capable biomimetic scaffolds for achieving enhanced efficacy in repairing various bone defects (e.g., as implants for healing bone screw holes or as barrier membranes for guided bone regeneration).

  1. Imaging of the Fibrous Cap in Atherosclerotic Carotid Plaque

    International Nuclear Information System (INIS)

    Saba, Luca; Potters, Fons; Lugt, Aad van der; Mallarini, Giorgio

    2010-01-01

    In the last two decades, a substantial number of articles have been published to provide diagnostic solutions for patients with carotid atherosclerotic disease. These articles have resulted in a shift of opinion regarding the identification of stroke risk in patients with carotid atherosclerotic disease. In the recent past, the degree of carotid artery stenosis was the sole determinant for performing carotid intervention (carotid endarterectomy or carotid stenting) in these patients. We now know that the degree of stenosis is only one marker for future cerebrovascular events. If one wants to determine the risk of these events more accurately, other parameters must be taken into account; among these parameters are plaque composition, presence and state of the fibrous cap (FC), intraplaque haemorrhage, plaque ulceration, and plaque location. In particular, the FC is an important structure for the stability of the plaque, and its rupture is highly associated with a recent history of transient ischaemic attack or stroke. The subject of this review is imaging of the FC.

  2. Controlled antiseptic/eosin release from chitosan-based hydrogel modified fibrous substrates.

    Science.gov (United States)

    Romano, Ilaria; Ayadi, Farouk; Rizzello, Loris; Summa, Maria; Bertorelli, Rosalia; Pompa, Pier Paolo; Brandi, Fernando; Bayer, Ilker S; Athanassiou, Athanassia

    2015-10-20

    Fibers of cellulose networks were stably coated with N-methacrylate glycol chitosan (MGC) shells using subsequent steps of dip coating and photo-curing. The photo-crosslinked MGC-coated cellulose networks preserved their fibrous structure. A model hydrophilic antiseptic solution containing eosin, chloroxylenol and propylene glycol was incorporated into the shells to study the drug release dynamics. Detailed drug release mechanism into phosphate buffered saline (PBS) solutions from coated and pristine fibers loaded with the antiseptic was investigated. The results show that the MGC-coated cellulose fibers enable the controlled gradual release of the drug for four days, as opposed to fast, instantaneous release from eosin coated pristine fibers. This release behavior was found to affect the antibacterial efficiency of the fibrous cellulose sheets significantly against Staphylococcus aureus and Candida albicans. In the case of the MGC-eosin functionalized system the antibacterial efficiency was as high as 85% and 90%, respectively, while for the eosin coated pristine cellulose system the efficiency was negative, indicating bacterial proliferation. Furthermore, the MGC-eosin system was shown to be efficacious in a model of wound healing in mice, reducing the levels of various pro-inflammatory cytokines that modulate early inflammatory phase responses. The results demonstrate good potential of these coated fibers for wound dressing and healing applications. Due to its easy application on common passive commercial fibrous dressings such as gauzes and cotton fibers, the method can render them active dressings in a cost effective way. Copyright © 2015. Published by Elsevier Ltd.

  3. Mapping local orientation of aligned fibrous scatterers for cancerous tissues using backscattering Mueller matrix imaging

    Science.gov (United States)

    He, Honghui; Sun, Minghao; Zeng, Nan; Du, E.; Liu, Shaoxiong; Guo, Yihong; Wu, Jian; He, Yonghong; Ma, Hui

    2014-10-01

    Polarization measurements are sensitive to the microstructure of tissues and can be used to detect pathological changes. Many tissues contain anisotropic fibrous structures. We obtain the local orientation of aligned fibrous scatterers using different groups of the backscattering Mueller matrix elements. Experiments on concentrically well-aligned silk fibers and unstained human papillary thyroid carcinoma tissues show that the m22, m33, m23, and m32 elements have better contrast but higher degeneracy for the extraction of orientation angles. The m12 and m13 elements show lower contrast, but allow us to determine the orientation angle for the fibrous scatterers along all directions. Moreover, Monte Carlo simulations based on the sphere-cylinder scattering model indicate that the oblique incidence of the illumination beam introduces some errors in the orientation angles obtained by both methods. Mapping the local orientation of anisotropic tissues may not only provide information on pathological changes, but can also give new leads to reduce the orientation dependence of polarization measurements.

  4. Linking rock fabric to fibrous mineralisation: a basic tool for the asbestos hazard

    Directory of Open Access Journals (Sweden)

    G. Vignaroli

    2011-05-01

    Full Text Available In recent years, many studies have addressed the effect on human health caused by asbestos exposures. As asbestos is a group of fibrous minerals that mainly occurs in mafic and ultramafic rocks (ophiolitic sequences, a close relationship between asbestos occurrence and the geological history of host rocks should be expected. By reviewing the existing literature and presenting characteristic examples, it is proposed a direct correspondence exists between the presence of fibrous minerals in ophiolites and the rock fabric systematics due to the combined activity of deformation, metamorphism/metasomatism, and rock/fluid interaction. Understanding the geological factors that may be at the origin of the nucleation/growth of fibrous minerals constitutes a necessary requirement for developing a methodological and analytical procedure to evaluate asbestos hazard (AH in the natural prototype (ophiolitic rocks. A parameterisation of the AH in function of the main geological processes that produce the rock fabric systematics in different tectonic/geodynamic settings is discussed. A geological multidisciplinary approach (based on geological-structural field evidence combined with textural, mineralogical, petrological, and geochemical investigations is proposed as the prerequisite for the evaluation of AH in natural environments. This approach, in particular, can provide a robust basis to formulate a procedural protocol finalised to the mitigation of asbestos effects in environments where these effects are still a real threat.

  5. Electrospinning of fibrous polymer scaffolds using positive voltage or negative voltage: a comparative study

    International Nuclear Information System (INIS)

    Tong Howang; Wang Min

    2010-01-01

    Electrospinning of fibrous tissue engineering scaffolds has been traditionally conducted using positive voltages. In the current study, positive voltage (PV) electrospinning and negative voltage (NV) electrospinning were investigated for forming fibrous membranes of poly(hydroxybutyrate-co-hydroxyvalerate) (PHBV). In both PV-electrospinning and NV-electrospinning, the fiber diameter generally increased with increasing needle inner diameter and PHBV concentration but decreased with increasing working distance. The use of a conductivity-enhancing surfactant, benzyl triethylammonium chloride (BTEAC), significantly reduced PHBV fiber diameters from the micron scale to the sub-micron scale. Interestingly, with increasing applied voltage, the fiber diameter increased for PV-electrospinning but decreased for NV-electrospinning. The PV-electrospun fibrous membranes from solutions without BTEAC (PVEfm) and with BTEAC (PVEfm-B) and NV-electrospun membranes from solutions without BTEAC (NVEfm) and with BTEAC (NVEfm-B) were characterized in terms of their structure, wettability, thermal properties and tensile properties. Both PVEfm and NVEfm exhibited similar water contact angles (∼104 0 ) but the contact angle of PVEfm-B or NVEfm-B was not measurable. The elongation at break of PVEfm-B or NVEfm-B was significantly higher than that of PVEfm or NVEfm. Using NV-electrospinning or a combination of NV- and PV-electrospinning may be very useful for developing suitable scaffolds for tissue engineering applications.

  6. pH responsiveness of fibrous assemblies of repeat-sequence amphipathic α-helix polypeptides.

    Science.gov (United States)

    Takei, Toshiaki; Tsumoto, Kouhei; Okonogi, Atsuhito; Kimura, Akiko; Kojima, Shuichi; Yazaki, Kazumori; Takei, Tsunetomo; Ueda, Takuya; Miura, Kin-ichiro

    2015-05-01

    We reported previously that our designed polypeptide α3 (21 residues), which has three repeats of a seven-amino-acid sequence (LETLAKA)3, forms not only an amphipathic α-helix structure but also long fibrous assemblies in aqueous solution. To address the relationship between the electrical states of the polypeptide and its α-helix and fibrous assembly formation, we characterized mutated polypeptides in which charged amino acid residues of α3 were replaced with Ser. We prepared the following polypeptides: 2Sα3 (LSTLAKA)3, in which all Glu residues were replaced with Ser residues; 6Sα3 (LETLASA)3, in which all Lys residues were replaced with Ser; and 2S6Sα3 (LSTLASA)3; in which all Glu and Lys residues were replaced with Ser. In 0.1M KCl, 2Sα3 formed an α-helix under basic conditions and 6Sα3 formed an α-helix under acid conditions. In 1M KCl, they both formed α-helices under a wide pH range. In addition, 2Sα3 and 6Sα3 formed fibrous assemblies under the same buffer conditions in which they formed α-helices. α-Helix and fibrous assembly formation by these polypeptides was reversible in a pH-dependent manner. In contrast, 2S6Sα3 formed an α-helix under basic conditions in 1M KCl. Taken together, these findings reveal that the charge states of the charged amino acid residues and the charge state of the Leu residue located at the terminus play an important role in α-helix formation. © 2015 The Protein Society.

  7. Conductive electrospun PANi-PEO/TiO{sub 2} fibrous membrane for photo catalysis

    Energy Technology Data Exchange (ETDEWEB)

    Neubert, Sebastian [National University of Singapore, 21 Lower Kent Ridge Road, Singapore 119077 (Singapore); Pliszka, Damian, E-mail: nnidp@nus.edu.sg [National University of Singapore, 21 Lower Kent Ridge Road, Singapore 119077 (Singapore); Thavasi, Velmurugan [National University of Singapore, 21 Lower Kent Ridge Road, Singapore 119077 (Singapore); Wintermantel, Erich [Technical University of Munich, Bolzmannstr. 15, 85748 Garching (Germany); Ramakrishna, Seeram [National University of Singapore, 21 Lower Kent Ridge Road, Singapore 119077 (Singapore); King Saud University, Riyadh 11451 (Saudi Arabia)

    2011-05-15

    Graphical abstract: - Abstract: The integration of electrospinning and electrospraying to prepare the fibrous catalytic filter membrane is demonstrated. The non-conductive polyethylene oxide (PEO) is blended with ({+-})-camphor-10-sulfonic acid (CSA) doped conductive polyaniline (PANi) for electrospinning. The conductive CSA/PANi-PEO composite fibers are produced upon electrospinning, which are used as the conductive collector for electrospraying process by which titanium dioxide (TiO{sub 2}) nanoparticles (NPs) are sprayed and allowed to adsorb on the fibers. The degree of adsorption and dispersion of nano TiO{sub 2} catalysts on the surface of the CSA/PANi-PEO fibers exhibit a stronger dependence on weight percentage (wt%) of PANi in PEO solution and the strength of electrical conductivity of the fibers used during electrospraying. CSA/PANi-PEO fibers as collector reduce the wastage of TiO{sub 2} NPs during electrospraying to lesser than 5%. Among the three different composition of PANi studied, PEO with 12 wt% PANi yields very uniform diameter and beads-free fibrous structure with higher electrical conductivity. 12 wt% CSA/PANi-PEO fibrous membrane is found to support for greater dispersion of TiO{sub 2} NPs. The photocatalytic activity of the as-prepared TiO{sub 2}-PANi-PEO catalytic membrane is tested against the toxicant simulant 2-chloroethyl phenyl sulfide (CEPS) under the ultraviolet light irradiation. It is observed that the TiO{sub 2} nanoparticles catalysts embedded PANi-PEO fibrous membrane decontaminated the toxicant CEPS significantly, which is due to uniform dispersion of the catalysts produced by the methodology.

  8. Heat resistant soy adhesives for structural wood products

    Science.gov (United States)

    Christopher G. Hunt; Charles Frihart; Jane O' Dell

    2009-01-01

    Because load-bearing bonded wood assemblies must support the structure during a fire, the limited softening and depolymerization of biobased polymers at elevated temperatures should be an advantage of biobased adhesives compared to fossil fuel-based adhesives. Because load-bearing bonded wood assemblies must support the structure during a fire, the limited softening...

  9. Predicting the Liquid Phase Mass Transfer Resistance of Structured Packings

    NARCIS (Netherlands)

    Olujic, Z.; Seibert, A.F.

    2014-01-01

    Published correlations for estimating the liquid phase mass transfer coefficients of structured packings are compared using experimental evidence on the efficiency of Montz-Pak B1–250MN and B1–500MN structured packings as measured in total reflux distillation tests using the

  10. Superplasticizer effect on cement paste structure and concrete freeze-thaw resistance

    Science.gov (United States)

    Shuldyakov, Kirill; Kramar, Lyudmila; Trofimov, Boris; Ivanov, Ilya

    2016-01-01

    Article presents the results of studies of various types of superplasticizer additives and their influence on concrete structure and resistance under cyclic freezing-thawing. Glenium ACE 430 was taken as a polycarboxylate superplasticizer, and SP-1 - as a naphthalene-formaldehyde superplasticizer. It is revealed that at identical structure, W/C and fluidity of concrete mix, application of the polycarboxylate superplasticizer, Glenium AC 430, in comparison to the naphthalene-formaldehyde one SP-1, facilitates the increase of the concrete grade in freeze and thaw resistance from F2300 to F2400, concrete freeze and thaw resistance can be possible even higher if the gravel with higher freeze and thaw resistance is applied. To assess the superplasticizers influence on cement paste structure tests of the phase composition of the cement paste of the studied concrete were conducted. It is established that the use of polycarboxylate superplasticizer together with silica fume facilitates formation of cement plaster structure from tobermorite gel. This gel has increased basicity and is resistant to crystallization due to cyclic freezing. It is shown that in the presence of SP-1+SF in the cement paste of concrete during hydration the structure of hydrosilicate phases preferably comprises of C-S-H(I) and C-S-H(II) phases which actively crystallize while cyclic freezing and thawing and reduce freeze-thaw resistance of concrete.

  11. The structure of denisovite, a fibrous nanocrystalline polytypic disordered `very complex' silicate, studied by a synergistic multi-disciplinary approach employing methods of electron crystallography and X-ray powder diffraction

    Directory of Open Access Journals (Sweden)

    Ira V. Rozhdestvenskaya

    2017-05-01

    Full Text Available Denisovite is a rare mineral occurring as aggregates of fibres typically 200–500 nm diameter. It was confirmed as a new mineral in 1984, but important facts about its chemical formula, lattice parameters, symmetry and structure have remained incompletely known since then. Recently obtained results from studies using microprobe analysis, X-ray powder diffraction (XRPD, electron crystallography, modelling and Rietveld refinement will be reported. The electron crystallography methods include transmission electron microscopy (TEM, selected-area electron diffraction (SAED, high-angle annular dark-field imaging (HAADF, high-resolution transmission electron microscopy (HRTEM, precession electron diffraction (PED and electron diffraction tomography (EDT. A structural model of denisovite was developed from HAADF images and later completed on the basis of quasi-kinematic EDT data by ab initio structure solution using direct methods and least-squares refinement. The model was confirmed by Rietveld refinement. The lattice parameters are a = 31.024 (1, b = 19.554 (1 and c = 7.1441 (5 Å, β = 95.99 (3°, V = 4310.1 (5 Å3 and space group P12/a1. The structure consists of three topologically distinct dreier silicate chains, viz. two xonotlite-like dreier double chains, [Si6O17]10−, and a tubular loop-branched dreier triple chain, [Si12O30]12−. The silicate chains occur between three walls of edge-sharing (Ca,Na octahedra. The chains of silicate tetrahedra and the octahedra walls extend parallel to the z axis and form a layer parallel to (100. Water molecules and K+ cations are located at the centre of the tubular silicate chain. The latter also occupy positions close to the centres of eight-membered rings in the silicate chains. The silicate chains are geometrically constrained by neighbouring octahedra walls and present an ambiguity with respect to their z position along these walls, with displacements between neighbouring layers being

  12. Oxidative stress inhibition and oxidant activity by fibrous clays.

    Science.gov (United States)

    Cervini-Silva, Javiera; Nieto-Camacho, Antonio; Gómez-Vidales, Virginia

    2015-09-01

    Fibrous clays (sepiolite, palygorskite) are produced at 1.2m tonnes per year and have a wide range of industrial applications needing to replace long-fibre length asbestos. However, information on the beneficial effects of fibrous clays on health remains scarce. This paper reports on the effect of sepiolite (Vallecas, Spain) and palygorskite (Torrejón El Rubio, Spain) on cell damage via oxidative stress (determined as the progress of lipid peroxidation, LP). The extent of LP was assessed using the Thiobarbituric Acid Reactive Substances assay. The oxidant activity by fibrous clays was quantified using Electron-Paramagnetic Resonance. Sepiolite and palygorskite inhibited LP, whereby corresponding IC50 values were 6557±1024 and 4250±289μgmL(-1). As evidenced by dose-response experiments LP inhibition by palygorskite was surface-controlled. Fibrous clay surfaces did not stabilize HO species, except for suspensions containing 5000μgmL(-1). A strong oxidant (or weak anti-oxidant) activity favours the inhibition of LP by fibrous clays. Copyright © 2015 Elsevier B.V. All rights reserved.

  13. Isolated orbital fibrous dysplasia associated with ipsilateral keratoconus.

    Science.gov (United States)

    Liarakos, Vasilios S; Ilari, Luca; Chalvatzis, Nikolaos; Papaparaskeva, Kleio; Mavrikakis, Ioannis

    2010-06-01

    Fibrous dysplasia is a primary orbital bone tumor, described as a benign disorder in which proliferation of fibrous tissue and osteoid replaces and distorts the bone from which it derives. Unilateral keratoconus is a rare entity. Herein, we report a case of an extensive ethmoidal fibrous dysplasia associated with ipsilateral keratoconus, and review the literature on the subject. A 22-year-old man presented with left painless proptosis evolving over 10 years. There was associated ipsilateral epiphora and gradual visual loss. On examination his visual acuity was 20/20 OD and CF OS. His left globe was displaced lateraly 12 mm, with 9 mm of proptosis. The extraocular movements were normal. Left nasolacrimal duct obstruction was noted. Clinical signs of keratoconus were present only in the left cornea. High resolution corneal topography confirmed unilateral keratoconus and a CT scan showed an ovoid mass with a well defined sclerotic margin arising from the left ethmoid sinus and invading the orbit. The patient underwent resection of the lesion via a modified Lynch incision. Complete regression of proptosis was observed immediately after surgery. Histopathological examination revealed irregular trabeculae of woven bone in different levels of maturation in a moderately cellular fibrous matrix without nuclear atypia. Trabeculae were without osteoblastic rimming or osteoclastic resorption. There has been no recurrence over a 2-year follow-up period. To our knowledge, the coexistence of unilateral isolated craniofacial fibrous dysplasia with ipsilateral keratoconus has not been reported so far.

  14. Craniofacial fibrous dysplasia - A review of current management techniques

    Directory of Open Access Journals (Sweden)

    Yadavalli Guruprasad

    2012-01-01

    Full Text Available Fibrous dysplasia is a pathologic condition of bone of unknown etiology with no apparent familial, hereditary or congenital basis. Lichtenstein first coined the term in 1938 and in 1942 he and Jaffe separated it from other fibro-osseous lesions. It is a bone tumor that, although benign, has the potential to cause significant cosmetic and functional disturbance, particularly in the craniofacial skeleton. Its management poses significant challenges to the surgeon. Craniofacial fibrous dysplasia is 1 of 3 types of fibrous dysplasia that can affect the bones of the craniofacial complex, including the mandible and maxilla. Fibrous dysplasia is a skeletal developmental disorder of the bone-forming mesenchyme that manifests as a defect in osteoblastic differentiation and maturation. It is a lesion of unknown etiology, uncertain pathogenesis, and diverse histopathology. Fibrous dysplasia represents about 2, 5% of all bone tumors and over 7% of all benign tumours. Over the years, we have gained a better understanding of its etiology, clinical behavior, and both surgical and non-surgical treatments.

  15. [Investigation of fibrous cultural materials by infrared spectroscopy].

    Science.gov (United States)

    Luo, Xi-yun; Du, Yi-ping; Shen, Mei-hua; Zhang, Wen-qing; Zhou, Xin-guang; Fang, Shu-ying; Zhang, Xuan

    2015-01-01

    Cultural fibrous material includes both important categories, i. e. textile and paper, consisting of precious cultural materials in museum, such as costume, painting, and manuscript. In recent years more and more connoisseur and conservator's concerns are, through nondestructive method, the authenticity and the ageing identification of these cultural relics especially made from fragile materials. In this research, we used attenuated total reflection infrared spectroscopy to identify five traditional textile fibers, alongside cotton, linen, wool, mulberry silk and tussah silk, and another five paper fibers alongside straw, wheat straw, long qisong, Chinese alpine rush and mulberry bar, which are commonly used for making Chinese traditional xuan paper. The research result showed that the animal fiber (wool, mulberry silk and tussah silk) and plant fiber (cotton and linen) were easier to be distinguished by comparing the peaks at 3 280 cm-1 belonging to NH stretching vibration and a serious peaks related to amide I to amide III. In the spectrum of wool, the peak at 1 076 cm-1 was assigned to the S-O stretching vibration absorption of cystine in wool structure and can be used to tell wool from silk. The spectrum of mulberry silk and tussah silk seems somewhat difficult to be identified, as well as the spectrum of cotton and linen. Five rural paper fibers all have obvious characteristic peaks at 3 330, 2 900 cm-1 which are related to OH and CH stretching vibration. In the fingerprint wavenumber range of 1 600 - 800 cm, the similar peaks also appeared at 1 370, 1 320 cm-1 and 1 162, 1 050 cm-1, both group peaks respectively are related to CH and CO vibration in the structure of cellulose and hemicellulose in paper fibers. Although there is more similarity of the infrared spectroscopy of these 5 paper fibers, some tiny difference in absorbance also can be found at 3 300 cm-1 and in the fingerprint range at 1 332, 1 203, and 1 050 cm-1 which are related to C-O-C vibration

  16. Evaluation of Transmission Line Model Structures for Silicide-to-Silicon Specific Contact Resistance Extraction

    NARCIS (Netherlands)

    Stavitski, N.; van Dal, Mark J.H.; Lauwers, Anne; Vrancken, Christa; Kovalgin, Alexeij Y.; Wolters, Robertus A.M.

    2008-01-01

    In order to measure silicide-to-silicon specific contact resistance �?c, transmission line model (TLM) structures were proposed as attractive candidates for embedding in CMOS processes. We optimized TLM structures for nickel silicide and platinum silicide and evaluated them for various doping levels

  17. Cross-bidge Kelvin resistor (CBKR) structures for measurement of low contact resistances

    NARCIS (Netherlands)

    Stavitski, N.; Klootwijk, J.H.; van Zeijl, H.W.; Boksteen, B.K.; Boksteen, B.K.; Kovalgin, Alexeij Y.; Wolters, Robertus A.M.

    2007-01-01

    A convenient test structure for measurement of the specific contact resistance (�?c) of metal-semiconductor junctions is the CBKR structure. During last few decades the parasitic factors which may strongly affect the measurements accuracy for �?c < 10-6 Ω • cm2 have been sufficiently discussed and

  18. Crystal structure of the TLDc domain of oxidation resistance protein 2 from zebrafish

    DEFF Research Database (Denmark)

    Blaise, Mickael; Alsarraf, Husam Mohammad Ali Baker; Wong, Jaslyn

    2012-01-01

    structure of the TLDc domain of the oxidation resistance protein 2 from zebrafish. The structure was determined by X-ray crystallography to atomic resolution (0.97Å) and adopts an overall globular shape. Two antiparallel β-sheets form a central β-sandwich, surrounded by two helices and two one-turn helices...

  19. Self-Centering Seismic Lateral Force Resisting Systems: High Performance Structures for the City of Tomorrow

    Directory of Open Access Journals (Sweden)

    Nathan Brent Chancellor

    2014-09-01

    Full Text Available Structures designed in accordance with even the most modern buildings codes are expected to sustain damage during a severe earthquake; however; these structures are expected to protect the lives of the occupants. Damage to the structure can require expensive repairs; significant business downtime; and in some cases building demolition. If damage occurs to many structures within a city or region; the regional and national economy may be severely disrupted. To address these shortcomings with current seismic lateral force resisting systems and to work towards more resilient; sustainable cities; a new class of seismic lateral force resisting systems that sustains little or no damage under severe earthquakes has been developed. These new seismic lateral force resisting systems reduce or prevent structural damage to nonreplaceable structural elements by softening the structural response elastically through gap opening mechanisms. To dissipate seismic energy; friction elements or replaceable yielding energy dissipation elements are also included. Post-tensioning is often used as a part of these systems to return the structure to a plumb; upright position (self-center after the earthquake has passed. This paper summarizes the state-of-the art for self-centering seismic lateral force resisting systems and outlines current research challenges for these systems.

  20. Corrosion-resistant multilayer structures with improved reflectivity

    Science.gov (United States)

    Soufli, Regina; Fernandez-Perea, Monica; Robinson, Jeff C.

    2013-04-09

    In one general embodiment, a thin film structure includes a substrate; a first corrosion barrier layer above the substrate; a reflective layer above the first corrosion barrier layer, wherein the reflective layer comprises at least one repeating set of sub-layers, wherein one of the sub-layers of each set of sub-layers being of a corrodible material; and a second corrosion barrier layer above the reflective layer. In another general embodiment, a system includes an optical element having a thin film structure as recited above; and an image capture or spectrometer device. In a further general embodiment, a laser according to one embodiment includes a light source and the thin film structure as recited above.

  1. Investigations on the porous resistance coefficients for fishing net structures

    DEFF Research Database (Denmark)

    Chen, Hao; Christensen, Erik Damgaard

    2016-01-01

    The porous media model has been successfully applied to numerical simulation of current and wave interaction with traditional permeable coastal structures such as breakwaters. Recently this model was employed to simulate flow through and around fishing net structures, where the unknown porous...... validation cases were carried out to examine the performance of the numerical model. This includes steady current flow through plane net panels and circular fish cages, and wave interaction with plane net panels. A variety of fishing nets with different solidity ratios were used in the validation cases, from...

  2. Fibrous dysplasia and ossifying fibroma of the paranasal sinuses.

    Science.gov (United States)

    Commins, D J; Tolley, N S; Milford, C A

    1998-10-01

    Fibro-osseous lesions involving the paranasal sinuses, the mid-face and anterior skull base are uncommon. In addition, there appears to be no clear pathological or clinical classification that embraces the variety of lesions that exhibit such diverse pathological and clinical behaviour, yet may still be referred to as a fibro-osseous lesion. The diagnosis of fibrous dysplasia and ossifying fibroma is made on a combination of clinical, radiological and pathological criteria. This paper emphasizes the clinical and pathological differences between fibrous dysplasia and ossifying fibroma. The more aggressive clinical behaviour of the latter is highlighted and a more radical surgical approach is recommended. In contradistinction, fibrous dysplasia can exhibit a more benign behaviour and radical surgery is not always justified. A clinicopathological distinction between these two conditions is important from a management perspective despite the fact that they both may be encompassed under the 'umbrella' term fibro-osseous lesion.

  3. A solitary fibrous tumor of the retroperitoneum: CT findings

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jeong Min; Kim, Chong Soo; Lee, Dong Keun; Cho, Baek Hwan [Chonbuk National Univ. College of Medicine, Chunju (Korea, Republic of); Han, Hyun Young [Euljy Mecical School, Seoul (Korea, Republic of)

    1999-01-01

    The solitary fibrous tumor is a rare spindle cell neoplasm of mesodermal origin. It usually arises in the pleura, though has recently been reported in the peritoneum and at nonserosal sites ; it is, however, extremely rare in the retroperitonum. The authors describe one case of a solitary fibrous tumor that occurred as a huge complex mass in the retroperitoneum of an adult. Preenhanced CT scans showed that the mass was sharply delineated from surrounding organs and that tumor density was the same as that of surrounding musculature. Peripheral Calcifications were noted, and postenhanced scans showed intense, gradual enhancement of solid portions of the mass, with nonenhanced cystic portions. Although not specific, solitary fibrous tumors must be included in the differential diagnosis of a large retroperitoneal tumor of complex consistency and with internal calcification.

  4. Radiological analysis of polyostotic fibrous dysplasia in skeletal system

    International Nuclear Information System (INIS)

    Shin, Ma Rie; Kim, Jin Sik; Kim, Han Suk; Park, Soo Soung

    1984-01-01

    Over a period of recent 3 years, the 5 cases of polyostotic fibrous dysplasia were proven histologically at National Medical Center, and they were evaluated and analyzed radiologically and clinically. The results were as follows: 1. The age of 5 patients ranged from 12 to 21. 2. In general, clinical symptoms of these patients were pain of affected sites and swelling , fracture, walking disturbance of lower extremities. 3. The order of frequent site of polyostotic fibrous dysplasia was skull (4 cases), femur (3 cases), maxilla (2 case), humerus, tibia, rib, radius, metacarpal bone and phalanx. 4. The characteristic radiological findings of polyostotic fibrous dysplasia were multicystic lesions with ground glass appearance, osteosclerosis, cortical thinning and pathologic fracture and deformity of long bones. Particularly, in the extremities, multicystic radiolucencies, groud glass appearance, shepherd's crook and coxa vara deformities were noticed, and in the skull and maxilla, sclerotic changes were principally demonstrated.

  5. Polyostotic Fibrous Dysplasia of Cranio-Maxillofacial Area

    Energy Technology Data Exchange (ETDEWEB)

    Han, Jin Woo; Kwon, Hyuk Rok; Lee, Jin Ho; Park, In Woo [Dept. of Oral and Maxillofacial Radiology, College of Dentistry, Kangnung National University, Kangnung (Korea, Republic of)

    2000-06-15

    Fibrous dysplasia is believed to be a hamartomatous developmental lesion of unknown origin. This disease is divided into monostotic and polyostotic fibrous dysplasia. Polyostotic type can be divided into craniofacial type, Lichtenstein-Jaffe type, and McCune-Albright syndrome. In this case, a 31-year-old female presented spontaneous loss of right mandibular teeth before 5 years and has shown continuous expansion of right mandibular alveolus. Through the radiographic view, the coarse pattern of the mixed radiopaque-lucent lesion was seen on the right mandibular body, and there was diffuse pattern of the mixed radiopaque-lucent lesion with ill-defined margin in the left mandibular body. In the right calvarium, the lesion had cotton-wool appearance. Partial excision for contouring, multiple extraction, and alveoloplasty were accomplished under general anesthesia for supportive treatment. Finally we could conclude this case was polyostotic fibrous dysplasia of cranio-maxillofacial area based on the clinical, radiologic finding, and histopathologic examination.

  6. Fibrous dysplasia of the jaws: a case report.

    Science.gov (United States)

    Chindia, M L

    1991-04-01

    This article reviews the present clinical, radiographic and histologic features of fibrous dysplastic lesions of the jaws. A case is presented of an apparently reactivated fibrous dysplastic jaw lesion, with evidence of cystic degeneration, in a 33-year-old female school-teacher who was first seen at the Department of Dental Surgery, University of Nairobi in March 1986. The dilemma in the management of fibrous dysplasia is reviewed and discussed. It is noted that while conservative surgical procedures remain the treatment of choice, situations arise where tremendous tissue activity would require early intervention by numerous cosmetic surgical shaving procedures. The present case, however, offers a unique management challenge due to the occurrence of extensive cystic degeneration in the mandible.

  7. Schools as Racial Spaces: Understanding and Resisting Structural Racism

    Science.gov (United States)

    Blaisdell, Benjamin

    2016-01-01

    Analyzing schools as racial spaces can help researchers examine the role of teachers in the perpetuation of structural racism in schools. Based on ethnographic and autoethnographic work, this article offers examples of schools as racial spaces, spaces where whiteness controlled access. It also highlights four teachers who pursued racial equity in…

  8. Lincosamides: Chemical structure, biosynthesis, mechanism of action, resistance, and applications

    Czech Academy of Sciences Publication Activity Database

    Spížek, Jaroslav; Řezanka, Tomáš

    2017-01-01

    Roč. 133, June 1 SI (2017), s. 20-28 ISSN 0006-2952 Institutional support: RVO:61388971 Keywords : Lincosamides * Chemical structure * Biosynthesis and mechanism of action Subject RIV: EE - Microbiology, Virology OBOR OECD: Microbiology Impact factor: 4.581, year: 2016

  9. Structural Studies of Bacterial Enzymes and their Relation to Antibiotic Resistance Mechanisms - Final Paper

    Energy Technology Data Exchange (ETDEWEB)

    Maltz, Lauren [SLAC National Accelerator Lab., Menlo Park, CA (United States)

    2015-08-27

    By using protein crystallography and X-ray diffraction, structures of bacterial enzymes were solved to gain a better understanding of how enzymatic modification acts as an antibacterial resistance mechanism. Aminoglycoside phosphotransferases (APHs) are one of three aminoglycoside modifying enzymes that confer resistance to the aminoglycoside antibiotics via enzymatic modification, rendering many drugs obsolete. Specifically, the APH(2”) family vary in their substrate specificities and also in their preference for the phosphate donor (ADP versus GDP). By solving the structures of members of the APH(2”) family of enzymes, we can see how domain movements are important to their substrate specificity. Our structure of the ternary complex of APH(2”)-IIIa with GDP and kanamycin, when compared to the known structures of APH(2”)-IVa, reveals that there are real physical differences between these two enzymes, a structural finding that explains why the two enzymes differ in their preferences for certain aminoglycosides. Another important group of bacterial resistance enzymes are the Class D β- lactamases. Oxacillinase carbapenemases (OXAs) are part of this enzyme class and have begun to confer resistance to ‘last resort’ drugs, most notably carbapenems. Our structure of OXA-143 shows that the conformational flexibility of a conserved hydrophobic residue in the active site (Val130) serves to control the entry of a transient water molecule responsible for a key step in the enzyme’s mechanism. Our results provide insight into the structural mechanisms of these two different enzymes

  10. A case of monostotic fibrous dysplasia of the maxillary sinus.

    Science.gov (United States)

    Erdem, L Oktay; Erdem, C Zuhal; Kargi, Sebnem

    2003-05-01

    Fibrous dysplasia is an uncommon benign disease of the bone, with slow progression. Monostotic involvement of the paranasal sinuses is rare. We report a 54-year-old woman who had complaints of facial asymmetry, chronic sinusitis, recurrent headaches, and nasal obstruction for two years. Conventional radiography showed opacification and expansion of the maxillary sinus. Axial and coronal computed tomography scans showed a heterogeneous mass that expanded the right maxillary sinus, leading to nasal obstruction and cortical thickening of the maxilla. No signs of destruction or erosion in the cortical bone were identified. An endonasal endoscopic biopsy was performed and the diagnosis of fibrous dysplasia was confirmed histologically.

  11. Treatment of craniofacial fibrous dysplasia: a case report.

    Science.gov (United States)

    Carini, F; Saggese, V; Porcaro, G; Baldoni, M

    2014-01-01

    The concept of "fibro-osseous lesions" of bone has evolved over the last several years and now includes two mayor entities: the fibrous dysplasia (FD) and the cement-ossifying fibroma (COF). Fibrous dysplasia is considered to be a developmental, tumor-like (hamartomatous), fibro-osseous disease of unknown etiology. There is a maxillary predominance when craniofacial FD occurs in the jaws and the maxillary sinus is commonly involved. Differentiation of OF from FD is important because of differences in treatment and behaviour. This article report a case of 60-year-old female with a history of painless unilateral palatal swelling.

  12. Cystic fibrous dysplasia mimicking giant cell tumor: MRI appearance

    Energy Technology Data Exchange (ETDEWEB)

    Okada, Kyoji; Yoshida, Sumiko [Department of Orthopaedics, Akita University School of Medicine, Akita (Japan); Okane, Kumiko [Department of Radiology, Akita University School of Medicine, Akita (Japan); Sageshima, Masato [Division of Clinical Pathology, Akita University Hospital, Akita (Japan)

    2000-01-01

    We report the case of a 43-year-old man who presented with an osteolytic and expansive lesion in the left distal femur mimicking a giant cell tumor. Magnetic resonance imaging (MRI) showed that most of the lesion was cystic, and histological examination revealed fibrous dysplasia with marked cystic degeneration. Radiographic findings of cystic fibrous dysplasia in the end of a long bone may be similar to those of a giant cell tumor, and a biopsy is essential for the final diagnosis. (orig.)

  13. Brisement force in fibrous ankylosis: A technique revisited

    Directory of Open Access Journals (Sweden)

    Udupikrishna M Joshi

    2016-01-01

    Full Text Available Fibrous ankylosis is a common complication of trauma to the temporomandibular joint (TMJ in children. Proper treatment and regular follow-up is necessary for its successful management. This report highlights a case of posttraumatic fibrous ankylosis successfully managed with brisement force-gradual tractional forces applied to the TMJ under local anesthesia without any associated complications. Mouth opening increased significantly from 15 to 35 mm. The patient was advised to perform rigorous physiotherapy at home, to maintain interincisal opening of 35 mm. The case was followed up for 6 months with no decrease in mouth opening.

  14. A Solitary Fibrous Tumor of the Pleura Revealed by Hiccups

    Directory of Open Access Journals (Sweden)

    A. Chafik

    2011-01-01

    Full Text Available Solitary fibrous tumors of the pleura are rare and benign primary localized tumors; they possess a malignant potential and thus should be excised. We report a case of a 43-year-old woman, who had suffered for 5 years from right basithoracic pain associated with progressive dyspnea and persistent hiccups during the last 6 months. We have not found any similar case in the literature. Further testing after excision by thoracotomy revealed a solitary fibrous pleural tumor. A brief discussion of the clinical presentation and incidence of these tumors is included.

  15. Defining the structural requirements for a helix in 23 S ribosomal RNA that confers erythromycin resistance

    DEFF Research Database (Denmark)

    Douthwaite, S; Powers, T; Lee, J Y

    1989-01-01

    The helix spanning nucleotides 1198 to 1247 (helix 1200-1250) in Escherichia coli 23 S ribosomal RNA (rRNA) is functionally important in protein synthesis, and deletions in this region confer erythromycin resistance. In order to define the structural requirements for resistance, we have dissected....... However, removal of either these or non-conserved nucleotides from helix 1200-1250 measurably reduces the efficiency of 23 S RNA in forming functional ribosomes. We have used chemical probing and a modified primer extension method to investigate erythromycin binding to wild-type and resistant ribosomes...

  16. Protein valves prepared by click reaction grafting of poly(N-isopropylacrylamide) to electrospun poly(vinyl chloride) fibrous membranes

    Science.gov (United States)

    Guo, Jian-Wei; Lin, Zhen-Yu; Chang, Chi-Jung; Lu, Chien-Hsing; Chen, Jem-Kun

    2018-05-01

    In this study, poly(vinyl chloride) (PVC) was electrospun into fibrous membranes and then reacted with NaN3 to generate azido-terminated PVC fibrous membranes. A propargyl-terminated poly(N-isopropylacrylamide) (PNIPAAm) was also synthesized and then grafted, through click reactions, onto the azido-terminated PVC fiber surface. Protrusion-, scale-, and joint-like structures of the PNIPAAm grafts on the PVC fibers were formed upon increasing the molecular weight of the PNIPAAm grafts. The PNIPAAm-grafted PVC fibrous mats exhibited completely wetted surfaces at 25 °C because of their high roughness. The static water contact angle of the PNIPAAm-grafted PVC fibrous mats reached 140° when the temperature was increased to 45 °C. This thermoresponsive behavior was significantly greater than that of the PNIPAAm grafted on a flat surface. Temperature-responsive membranes were constructed having a pore size of 1.38 μm and applied as protein valves to block and release an antibody (fluorescein-conjugated AffiniPure goat anti-rabbit IgG). At 25 °C, the collection efficiency remained at 94% for antibody concentrations up to 60 ng/L. As the temperature increased to 45 °C, the collection efficiency decreased abruptly, to 4%, when the antibody concentration was greater than 20 ng/L. Accordingly, this system of PNIPAAm-grafted PVC fibers functioned as a protein valve allowing the capture and concentration of proteins.

  17. Prediction of HIV drug resistance from genotype with encoded three-dimensional protein structure.

    Science.gov (United States)

    Yu, Xiaxia; Weber, Irene T; Harrison, Robert W

    2014-01-01

    Drug resistance has become a severe challenge for treatment of HIV infections. Mutations accumulate in the HIV genome and make certain drugs ineffective. Prediction of resistance from genotype data is a valuable guide in choice of drugs for effective therapy. In order to improve the computational prediction of resistance from genotype data we have developed a unified encoding of the protein sequence and three-dimensional protein structure of the drug target for classification and regression analysis. The method was tested on genotype-resistance data for mutants of HIV protease and reverse transcriptase. Our graph based sequence-structure approach gives high accuracy with a new sparse dictionary classification method, as well as support vector machine and artificial neural networks classifiers. Cross-validated regression analysis with the sparse dictionary gave excellent correlation between predicted and observed resistance. The approach of encoding the protein structure and sequence as a 210-dimensional vector, based on Delaunay triangulation, has promise as an accurate method for predicting resistance from sequence for drugs inhibiting HIV protease and reverse transcriptase.

  18. Substrate-bound structure of the E. coli multidrug resistance transporter MdfA.

    Science.gov (United States)

    Heng, Jie; Zhao, Yan; Liu, Ming; Liu, Yue; Fan, Junping; Wang, Xianping; Zhao, Yongfang; Zhang, Xuejun C

    2015-09-01

    Multidrug resistance is a serious threat to public health. Proton motive force-driven antiporters from the major facilitator superfamily (MFS) constitute a major group of multidrug-resistance transporters. Currently, no reports on crystal structures of MFS antiporters in complex with their substrates exist. The E. coli MdfA transporter is a well-studied model system for biochemical analyses of multidrug-resistance MFS antiporters. Here, we report three crystal structures of MdfA-ligand complexes at resolutions up to 2.0 Å, all in the inward-facing conformation. The substrate-binding site sits proximal to the conserved acidic residue, D34. Our mutagenesis studies support the structural observations of the substrate-binding mode and the notion that D34 responds to substrate binding by adjusting its protonation status. Taken together, our data unveil the substrate-binding mode of MFS antiporters and suggest a mechanism of transport via this group of transporters.

  19. Structural analysis of base substitutions in Thermus thermophilus 16S rRNA conferring streptomycin resistance.

    Science.gov (United States)

    Demirci, Hasan; Murphy, Frank V; Murphy, Eileen L; Connetti, Jacqueline L; Dahlberg, Albert E; Jogl, Gerwald; Gregory, Steven T

    2014-08-01

    Streptomycin is a bactericidal antibiotic that induces translational errors. It binds to the 30S ribosomal subunit, interacting with ribosomal protein S12 and with 16S rRNA through contacts with the phosphodiester backbone. To explore the structural basis for streptomycin resistance, we determined the X-ray crystal structures of 30S ribosomal subunits from six streptomycin-resistant mutants of Thermus thermophilus both in the apo form and in complex with streptomycin. Base substitutions at highly conserved residues in the central pseudoknot of 16S rRNA produce novel hydrogen-bonding and base-stacking interactions. These rearrangements in secondary structure produce only minor adjustments in the three-dimensional fold of the pseudoknot. These results illustrate how antibiotic resistance can occur as a result of small changes in binding site conformation. Copyright © 2014, American Society for Microbiology. All Rights Reserved.

  20. Intrusion resistant underground structure (IRUS) : design and operations

    International Nuclear Information System (INIS)

    Lange, B.A.

    1997-01-01

    The safety case for the IRUS low-level radioactive waste disposal facility is based on the fact that IRUS will contain three specific types of wastes only. The types of these wastes are baled wastes, bituminized incinerator ash, and bituminized reverse osmosis concentrate. IRUS will be a below-ground vault consisting of an open bottom reinforced-concrete structure (approximate dimensions 30m x 20m x 8m) with a reinforced-concrete roof. This paper covers the vault design and construction and operational features. 2 tabs

  1. Intrusion resistant underground structure (IRUS) : design and operations

    Energy Technology Data Exchange (ETDEWEB)

    Lange, B.A. [Atomic Energy of Canada Ltd., Chalk River, ON (Canada)

    1997-12-31

    The safety case for the IRUS low-level radioactive waste disposal facility is based on the fact that IRUS will contain three specific types of wastes only. The types of these wastes are baled wastes, bituminized incinerator ash, and bituminized reverse osmosis concentrate. IRUS will be a below-ground vault consisting of an open bottom reinforced-concrete structure (approximate dimensions 30m x 20m x 8m) with a reinforced-concrete roof. This paper covers the vault design and construction and operational features. 2 tabs.

  2. Structure of Ti-6Al-4V nanostructured titanium alloy joint obtained by resistance spot welding

    Science.gov (United States)

    Klimenov, V. A.; Kurgan, K. A.; Chumaevskii, A. V.; Klopotov, A. A.; Gnyusov, S. F.

    2016-01-01

    The structure of weld joints of the titanium alloy Ti-6Al-4V in the initial ultrafine-grained state, obtained by resistance spot welding, is studied using the optical and scanning electron microscopy method and the X-ray structure analysis. The carried out studies show the relationship of the metal structure in the weld zone with main joint zones. The structure in the core zone and the heat affected zone is represented by finely dispersed grains of needle-shaped martensite, differently oriented in these zones. The change in the microhardness in the longitudinal section of the weld joint clearly correlates with structural changes during welding.

  3. Structure of Ti-6Al-4V nanostructured titanium alloy joint obtained by resistance spot welding

    Energy Technology Data Exchange (ETDEWEB)

    Klimenov, V. A., E-mail: klimenov@tpu.ru [Tomsk State University of Architecture and Building, 2 Solyanaya Sq, Tomsk, 634003 (Russian Federation); National Research Tomsk Polytechnic University, 30 Lenin Av., Tomsk, 634050 (Russian Federation); Kurgan, K. A., E-mail: kirill-k2.777@mail.ru [Tomsk State University of Architecture and Building, 2 Solyanaya Sq, Tomsk, 634003 (Russian Federation); Chumaevskii, A. V., E-mail: tch7av@gmail.com [Institute of Strength Physics and Materials Science, Siberian Branch of the Russian Academy of Sciences, 2/4 Akademicheskii pr., Tomsk, 634021 (Russian Federation); Klopotov, A. A., E-mail: klopotovaa@tsuab.ru [Tomsk State University of Architecture and Building, 2 Solyanaya Sq, Tomsk, 634003 (Russian Federation); National Research Tomsk State University, 36 Lenin Ave., Tomsk, 634050 (Russian Federation); Gnyusov, S. F., E-mail: gnusov@rambler.ru [National Research Tomsk Polytechnic University, 30 Lenin Av., Tomsk, 634050 (Russian Federation)

    2016-01-15

    The structure of weld joints of the titanium alloy Ti-6Al-4V in the initial ultrafine-grained state, obtained by resistance spot welding, is studied using the optical and scanning electron microscopy method and the X-ray structure analysis. The carried out studies show the relationship of the metal structure in the weld zone with main joint zones. The structure in the core zone and the heat affected zone is represented by finely dispersed grains of needle-shaped martensite, differently oriented in these zones. The change in the microhardness in the longitudinal section of the weld joint clearly correlates with structural changes during welding.

  4. A Blast-Resistant Method Based on Wave Converters with Spring Oscillator for Underground Structures

    Directory of Open Access Journals (Sweden)

    Yu Zhang

    2017-01-01

    Full Text Available Researches on blast-resistant measures for underground structures such as tunnels and underground shopping malls are of great importance for their significant role in economic and social development. In this paper, a new blast-resistant method based on wave converters with spring oscillator for underground structures was put forward, so as to convert the shock wave with high frequency and high peak pressure to the periodic stress wave with low frequency and low peak pressure. The conception and calculation process of this new method were introduced. The mechanical characteristics and motion evolution law of wave converters were deduced theoretically. Based on the theoretical deduction results and finite difference software FLAC3D, the dynamic responses of the new blast-resistant structure and the traditional one were both calculated. Results showed that, after the deployment of wave converters, the peak absolute values of the bending moment, shear force, and axial force of the structure decreased generally, which verified the good blast-resistant effect of the new blast-resistant method.

  5. Fibrous dysplasia of the jaws associated with secondary hyperparathyroidism: a case report

    Energy Technology Data Exchange (ETDEWEB)

    Whi, Jung Hyun; Kim, Young Joo; Chun, Kyung Ah; Kim, Ki Tae; Chang, Eun Deok; Kim, Young Ok; Lee, Won [The Catholic University of Korea, Uijongbu (Korea, Republic of)

    2007-06-15

    There have been few reports on fibrous dyplasia associated with secondary hyperparathyroidism. We report a case of a hemodialysis patient with secondary hyperparathyroidism concomitant with fibrous dysplasia of the jaws causing an abnormal deformity.

  6. Fibrous dysplasia of the jaws associated with secondary hyperparathyroidism: a case report

    International Nuclear Information System (INIS)

    Whi, Jung Hyun; Kim, Young Joo; Chun, Kyung Ah; Kim, Ki Tae; Chang, Eun Deok; Kim, Young Ok; Lee, Won

    2007-01-01

    There have been few reports on fibrous dyplasia associated with secondary hyperparathyroidism. We report a case of a hemodialysis patient with secondary hyperparathyroidism concomitant with fibrous dysplasia of the jaws causing an abnormal deformity

  7. Quantification of feather structure, wettability and resistance to liquid penetration

    Science.gov (United States)

    Srinivasan, Siddarth; Chhatre, Shreerang S.; Guardado, Jesus O.; Park, Kyoo-Chul; Parker, Andrew R.; Rubner, Michael F.; McKinley, Gareth H.; Cohen, Robert E.

    2014-01-01

    Birds in the cormorant (Phalacrocoracidae) family dive tens of metres into water to prey on fish while entraining a thin layer of air (a plastron film) within the microstructures of their feathers. In addition, many species within the family spread their wings for long periods of time upon emerging from water. To investigate whether wetting and wing-spreading are related to feather structure, microscopy and photographic studies have previously been used to extract structural parameters for barbs and barbules. In this work, we describe a systematic methodology to characterize the quasi-hierarchical topography of bird feathers that is based on contact angle measurements using a set of polar and non-polar probing liquids. Contact angle measurements on dip-coated feathers of six aquatic bird species (including three from the Phalacrocoracidae family) are used to extract two distinguishing structural parameters, a dimensionless spacing ratio of the barbule (D*) and a characteristic length scale corresponding to the spacing of defect sites. The dimensionless spacing parameter can be used in conjunction with a model for the surface topography to enable us to predict a priori the apparent contact angles of water droplets on feathers as well as the water breakthrough pressure required for the disruption of the plastron on the feather barbules. The predicted values of breakthrough depths in water (1–4 m) are towards the lower end of typical diving depths for the aquatic bird species examined here, and therefore a representative feather is expected to be fully wetted in a typical deep dive. However, thermodynamic surface energy analysis based on a simple one-dimensional cylindrical model of the feathers using parameters extracted from the goniometric analysis reveals that for water droplets on feathers of all six species under consideration, the non-wetting ‘Cassie–Baxter’ composite state represents the global energy minimum of the system. By contrast, for other

  8. Correlation of HIV protease structure with Indinavir resistance: a data mining and neural networks approach

    Science.gov (United States)

    Draghici, Sorin; Cumberland, Lonnie T., Jr.; Kovari, Ladislau C.

    2000-04-01

    This paper presents some results of data mining HIV genotypic and structural data. Our aim is to try to relate structural features of HIV enzymes essential to its reproductive abilities to the drug resistance phenomenon. This paper concentrates on the HIV protease enzyme and Indinavir which is one of the FDA approved protease inhibitors. Our starting point was the current list of HIV mutations related to drug resistance. We used the fact that some molecular structures determined through high resolution X-ray crystallography were available for the protease-Indinavir complex. Starting with these structures and the known mutations, we modelled the mutant proteases and studied the pattern of atomic contacts between the protease and the drug. After suitable pre- processing, these patterns have been used as the input of our data mining process. We have used both supervised and unsupervised learning techniques with the aim of understanding the relationship between structural features at a molecular level and resistance to Indinavir. The supervised learning was aimed at predicting IC90 values for arbitrary mutants. The SOFM was aimed at identifying those structural features that are important for drug resistance and discovering a classifier based on such features. We have used validation and cross validation to test the generalization abilities of the learning paradigm we have designed. The straightforward supervised learning was able to learn very successfully but validation results are less than satisfactory. This is due to the insufficient number of patterns in the training set which in turn is due to the scarcity of the available data. The data mining using SOFM was very successful. We have managed to distinguish between resistant and non-resistant mutants using structural features. We have been able to divide all reported HIV mutants into several categories based on their 3- dimensional molecular structures and the pattern of contacts between the mutant protease and

  9. Optical reflectance in fibrous tissues and skeletal muscles

    Science.gov (United States)

    Ranasinghesagara, Janaka C.

    We studied two biological tissues with optically anisotropic structures: high moisture soy protein extrudates and skeletal muscles. High moisture extrusion has been used to produce vegetable meat analogs that resemble real animal meat and have significant health benefits. Since visual and textural properties are key factors for consumer acceptance, assessing fiber formation in the extruded soy protein product is important for quality control purpose. A non-destructive method based on photon migration was developed to measure fiber formation in extruded soy proteins. The measured fiber formation index in intact samples showed good agreement with that obtained from image analysis on peeled samples. By implementing this new method in a fast laser scanning system, we have acquired two dimensional mappings of fiber formation and orientation in the entire sample in real time. In addition to fibrous structures, skeletal muscles have a unique periodic sarcomere structure which produces strong light diffractions. However, inconsistent experimental results have been reported in single fiber diffraction studies. By applying the three-dimensional coupled wave theory in a physical sarcomere model, we found that a variety of experimental observations can be explained if inhomogeneous muscle morphological profiles are considered. We also discovered that the sarcomere structure produced a unique optical reflectance pattern in whole muscle. None of the existing light propagation theories are able to describe this pattern. We developed a Monte Carlo model incorporating the sarcomere diffraction effect. The simulated results quantitatively resemble the unique patterns observed in experiments. We used a set of parameters to quantify the optical reflectance profiles produced by a point incident light in whole muscle. Two parameters, q and B, were obtained by numerically fitting the equi-intensity contours of the reflectance pattern. Two spatial gradients were calculated along the

  10. Meckel's Diverticulum associated with a thin fibrous band causing ...

    African Journals Online (AJOL)

    We report a case of an infant, three and half month old who presented with acute abdomen. Investigations including complete blood count and X-ray abdomen were non informative apart from showing evidence of intestinal obstruction. On abdominal exploration, there was a thin fibrous band attached to the apex of Meckel's ...

  11. Use of Zoledronic Acid in Paediatric Craniofacial Fibrous Dysplasia

    Directory of Open Access Journals (Sweden)

    Chiara Di Pede

    2016-01-01

    Full Text Available We describe a case of a paediatric patient affected by mandibular fibrous dysplasia (FD with severe and chronic pain who was successfully treated with zoledronic acid (ZOL: a third-generation bisphosphonate. Further research is needed to assess its safety and efficacy as a treatment option for FD in the paediatric population.

  12. Effects of Different Sources of Non-Fibrous Carbohydrate on ...

    African Journals Online (AJOL)

    Dr.taimouri

    fibre carbohydrate .... Non-fibrous carbohydrate (NFC) was calculated as: ..... Food Res. 35, 99-112. O'Doherty, J.V., Maher, P.F. & Crosby, T.F., 1997. The performance of pregnant ewes and their progeny when offered grass silage, maize silage or ...

  13. An unusual case of fibrous dysplasia of the maxillary sinus.

    Science.gov (United States)

    Crawford, Larry B

    2003-12-01

    Fibrous dysplasia of the maxillary sinus might initially become apparent because of facial asymmetry. It can be differentiated from other osseo-odontogenic dysplasias radiographically by its occupancy of the affected sinus and by its diffuse, ground-glass, radiopaque appearance; it can be further confirmed with histologic findings. It is normally self-limiting in growth and does not usually become malignant.

  14. Frictional behaviour of high performance fibrous tows: Friction experiments

    NARCIS (Netherlands)

    Cornelissen, Bo; Rietman, Bert; Akkerman, Remko

    2013-01-01

    Tow friction is an important mechanism in the production and processing of high performance fibrous tows. The frictional behaviour of these tows is anisotropic due to the texture of the filaments as well as the tows. This work describes capstan experiments that were performed to measure the

  15. Giant solitary fibrous tumor of the lung: A case report

    OpenAIRE

    Xiao, Ping; Sun, Linlin; Zhong, Diansheng; Lian, Linjuan; Xu, Dongbo

    2014-01-01

    A solitary fibrous tumor arising from the lung parenchyma is rarely described. Here, we present the clinical, imaging, and histological features of a case of a 54-year-old woman with an incidental lung mass of the right lower lobe on a chest radiograph.

  16. Electrospinning of caseinates to create protective fibrous mats

    Science.gov (United States)

    Electrospinning is a nonthermal process that produces fibers on the micron- or nano-scale from a polymer solution. If produced by electrospinning of biopolymer solutions, fibrous mats may be created for protecting foods and allowing for the preservation and controlled release of bioactives for healt...

  17. Keratins are the widely distributed fibrous proteins of our ...

    African Journals Online (AJOL)

    SAJID DANWAR

    2013-01-17

    Jan 17, 2013 ... Keratins are the widely distributed fibrous proteins of our environment. Keratinase are proteolytic enzymes responsible for hydrolyzing insoluble keratin largely produced by microorganisms including fungi. The isolation, identification and characterization of a non-dermatophytic keratinolytic fungal strain of ...

  18. Molecular snapshot of Mycobacterium tuberculosis population structure and drug-resistance in Kyrgyzstan.

    Science.gov (United States)

    Mokrousov, Igor; Isakova, Jainagul; Valcheva, Violeta; Aldashev, Almaz; Rastogi, Nalin

    2013-09-01

    Kyrgyzstan is a post-Soviet country in Central Asia marked with high incidence and mortality rates of tuberculosis (TB). The present study provided first assessment of Mycobacterium tuberculosis population structure and drug-resistance in civilian population here. The collection included 103 M. tuberculosis DNA samples subjected to the analysis of rifampin and isoniazid resistance mutations and spoligotyping. The major spoligotype-defined families were Beijing (n = 62), T (n = 14), LAM (n = 9), Ural-2 (n = 6) and Ural-1 (n = 3). Genotypically, 20 isolates were RIF-resistant, 28 were INH-resistant, 17 were multidrug-resistant. Drug resistant isolates were more prevalent among Beijing than non-Beijing groups (P = 0.03). The predominance of the mainly "Russian" spoligotypes among the non-Beijing strains (LAM-RUS and Ural-1) in this study along with previously demonstrated prevalence of the Russia-specific subtype of the Beijing family in Kyrgyz prison (Mokrousov et al., 2009) suggest that the current population structure of M. tuberculosis in Kyrgyzstan has been mainly formed within the course of the 20th century when the country was a part of the Russian Empire and Soviet Union. On the other hand, a prevalence of the Asia-specific Ural-2 type in the oldest age group (68-85 years old; P Kyrgyzstan. Copyright © 2013 Elsevier Ltd. All rights reserved.

  19. The structure of FIV reverse transcriptase and its implications for non-nucleoside inhibitor resistance.

    Directory of Open Access Journals (Sweden)

    Meytal Galilee

    2018-01-01

    Full Text Available Reverse transcriptase (RT is the target for the majority of anti-HIV-1 drugs. As with all anti-AIDS treatments, continued success of RT inhibitors is persistently disrupted by the occurrence of resistance mutations. To explore latent resistance mechanisms potentially accessible to therapeutically challenged HIV-1 viruses, we examined RT from the related feline immunodeficiency virus (FIV. FIV closely parallels HIV-1 in its replication and pathogenicity, however, is resistant to all non-nucleoside inhibitors (NNRTI. The intrinsic resistance of FIV RT is particularly interesting since FIV harbors the Y181 and Y188 sensitivity residues absent in both HIV-2 and SIV. Unlike RT from HIV-2 or SIV, previous efforts have failed to make FIV RT susceptible to NNRTIs concluding that the structure or flexibility of the feline enzyme must be profoundly different. We report the first crystal structure of FIV RT and, being the first structure of an RT from a non-primate lentivirus, enrich the structural and species repertoires available for RT. The structure demonstrates that while the NNRTI binding pocket is conserved, minor subtleties at the entryway can render the FIV RT pocket more restricted and unfavorable for effective NNRTI binding. Measuring NNRTI binding affinity to FIV RT shows that the "closed" pocket configuration inhibits NNRTI binding. Mutating the loop residues rimming the entryway of FIV RT pocket allows for NNRTI binding, however, it does not confer sensitivity to these inhibitors. This reveals a further layer of resistance caused by inherent FIV RT variances that could have enhanced the dissociation of bound inhibitors, or, perhaps, modulated protein plasticity to overcome inhibitory effects of bound NNRTIs. The more "closed" conformation of FIV RT pocket can provide a template for the development of innovative drugs that could unlock the constrained pocket, and the resilient mutant version of the enzyme can offer a fresh model for the study

  20. Solitary Fibrous Tumour of the Pleura – Cases Analysis

    International Nuclear Information System (INIS)

    Jadczak, Przemysław; Guz, Wiesław; Kaznowska, Ewa; Ramotowski, Radosław; Szalacha-Tarała, Ewa; Górecki, Andrzej; Samojedny, Antoni

    2014-01-01

    Isolated fibrous tumor of the pleura (SFTP – Solitary fibrous tumour of the pleura/localized fibrous tumour of the pleura) is a rare primary tumour of the pleura of mesenchymal origin. In most cases, it is a benign lesion. It is composed of spindle cells similar to fibroblasts and derives probably from submesothelial mesenchyme. The aim of the study was to analyze clinical symptoms, incidence, possibility of suggesting the diagnosis on the basis of imaging tests, and confirmation of the diagnosis in pathological tests with regard to studies of histochemistry examination. Clinical and morphological material obtained from 14 patients from Department of Thoracic Surgery of Subcarpathian Chest Disease Center treated between year 2004 and 2010 was analysed. In the first stage, selected cases of patients with isolated fibrous tumour of the pleura were chosen from the archives and the analysis of their medical history was carried out. Basic information about age, gender, medical history, smoking habit, physical examination and results of imaging, endoscopic and morphological examinations were noted. The second parallel component of the study was pathomorphological examinations of the surgical material obtained from the patients, including the assessment of morphology and immunohistochemistry. Of the 14 examined patients, fibrous tumour occurred in 8 men and 6 women. The age range of the patients was 37–73 years, with a peak attributable to the 6 th decade of life. In 8 patients the tumour was detected incidentally during routine examinations. In 7 patients there were no clinical signs of respiratory disease, and if present, then the most common complaint was shortness of breath. Regarding symptoms not connected with the respiratory system, anemia occurred most frequently. Fibrous tumour of the pleura was more often associated with the visceral pleura than with the parietal pleura. The largest lesion was approximately 20 cm in size. Fibrous tumour of the pleura is a

  1. Mathematical model of geometry and fibrous structure of the heart.

    Science.gov (United States)

    Nielsen, P M; Le Grice, I J; Smaill, B H; Hunter, P J

    1991-04-01

    We developed a mathematical representation of ventricular geometry and muscle fiber organization using three-dimensional finite elements referred to a prolate spheroid coordinate system. Within elements, fields are approximated using basis functions with associated parameters defined at the element nodes. Four parameters per node are used to describe ventricular geometry. The radial coordinate is interpolated using cubic Hermite basis functions that preserve slope continuity, while the angular coordinates are interpolated linearly. Two further nodal parameters describe the orientation of myocardial fibers. The orientation of fibers within coordinate planes bounded by epicardial and endocardial surfaces is interpolated linearly, with transmural variation given by cubic Hermite basis functions. Left and right ventricular geometry and myocardial fiber orientations were characterized for a canine heart arrested in diastole and fixed at zero transmural pressure. The geometry was represented by a 24-element ensemble with 41 nodes. Nodal parameters fitted using least squares provided a realistic description of ventricular epicardial [root mean square (RMS) error less than 0.9 mm] and endocardial (RMS error less than 2.6 mm) surfaces. Measured fiber fields were also fitted (RMS error less than 17 degrees) with a 60-element, 99-node mesh obtained by subdividing the 24-element mesh. These methods provide a compact and accurate anatomic description of the ventricles suitable for use in finite element stress analysis, simulation of cardiac electrical activation, and other cardiac field modeling problems.

  2. Hybrid Ceramic Matrix Fibrous Composites: an Overview

    Science.gov (United States)

    Naslain, R.

    2011-10-01

    Ceramic-Matrix Composites (CMCs) consist of a ceramic fiber architecture in a ceramic matrix, bonded together through a thin interphase. The present contribution is limited to non-oxide CMCs. Their constituents being oxidation-prone, they are protected by external coatings. We state here that CMCs display a hybrid feature, when at least one of their components is not homogeneous from a chemical or microstructural standpoint. Hybrid fiber architectures are used to tailor the mechanical or thermal CMC-properties whereas hybrid interphases, matrices and coatings to improve CMC resistance to aggressive environments.

  3. Hybrid Ceramic Matrix Fibrous Composites: an Overview

    Energy Technology Data Exchange (ETDEWEB)

    Naslain, R, E-mail: naslain@lcts.u-bordeaux1.fr [University of Bordeaux 3, Allee de La Boetie, 33600 Pessac (France)

    2011-10-29

    Ceramic-Matrix Composites (CMCs) consist of a ceramic fiber architecture in a ceramic matrix, bonded together through a thin interphase. The present contribution is limited to non-oxide CMCs. Their constituents being oxidation-prone, they are protected by external coatings. We state here that CMCs display a hybrid feature, when at least one of their components is not homogeneous from a chemical or microstructural standpoint. Hybrid fiber architectures are used to tailor the mechanical or thermal CMC-properties whereas hybrid interphases, matrices and coatings to improve CMC resistance to aggressive environments.

  4. Hybrid Ceramic Matrix Fibrous Composites: an Overview

    International Nuclear Information System (INIS)

    Naslain, R

    2011-01-01

    Ceramic-Matrix Composites (CMCs) consist of a ceramic fiber architecture in a ceramic matrix, bonded together through a thin interphase. The present contribution is limited to non-oxide CMCs. Their constituents being oxidation-prone, they are protected by external coatings. We state here that CMCs display a hybrid feature, when at least one of their components is not homogeneous from a chemical or microstructural standpoint. Hybrid fiber architectures are used to tailor the mechanical or thermal CMC-properties whereas hybrid interphases, matrices and coatings to improve CMC resistance to aggressive environments.

  5. Structural Basis for Streptogramin B Resistance in Staphylococcus aureus by Virginiamycin B Lyase

    Energy Technology Data Exchange (ETDEWEB)

    Korczynska,M.; Mukhtar, T.; Wright, G.; Berghuis, A.

    2007-01-01

    The streptogramin combination therapy of quinupristin-dalfopristin (Synercid) is used to treat infections caused by bacterial pathogens, such as methicillin-resistant Staphylococcus aureus and vancomycin-resistant Enterococcus faecium. However, the effectiveness of this therapy is being compromised because of an increased incidence of streptogramin resistance. One of the clinically observed mechanisms of resistance is enzymatic inactivation of the type B streptogramins, such as quinupristin, by a streptogramin B lyase, i.e., virginiamycin B lyase (Vgb). The enzyme catalyzes the linearization of the cyclic antibiotic via a cleavage that requires a divalent metal ion. Here, we present crystal structures of Vgb from S. aureus in its apoenzyme form and in complex with quinupristin and Mg{sup 2+} at 1.65- and 2.8-{angstrom} resolution, respectively. The fold of the enzyme is that of a seven-bladed {beta}-propeller, although the sequence reveals no similarity to other known members of this structural family. Quinupristin binds to a large depression on the surface of the enzyme, where it predominantly forms van der Waals interactions. Validated by site-directed mutagenesis studies, a reaction mechanism is proposed in which the initial abstraction of a proton is facilitated by a Mg{sup 2+}-linked conjugated system. Analysis of the Vgb-quinupristin structure and comparison with the complex between quinupristin and its natural target, the 50S ribosomal subunit, reveals features that can be exploited for developing streptogramins that are impervious to Vgb-mediated resistance.

  6. Case Report of a Satin Guinea Pig with Fibrous Osteodystrophy That Resembles Human Pseudohypoparathyroidism

    Directory of Open Access Journals (Sweden)

    Miguel Gallego

    2017-01-01

    Full Text Available A case report of a 2-year-old female satin guinea pig with a history of dental overgrowth and lameness and radiological lesions of fibrous osteodystrophy is presented. The most relevant clinical findings were bone demineralization, high level of parathyroid hormone (PTH, normophosphatemia, normal ionized calcium, and low total thyroxine (tT4 with a normal renal function. Long-term treatment was based on teeth coronal reduction and maintaining a balanced diet. PTH measurement was performed with a kit suitable for rats to test 4 different paired samples of guinea pigs and resulted in similar results for each pair of measurements. Two kits routinely employed in dogs and cats failed in measuring PTH in guinea pig serum samples. The ionized calcium, PTH, and tT4 values, not previously reported in similar cases, were obtained. The determination of tT4 could be useful in the diagnosis of fibrous osteodystrophy in guinea pigs. The observed findings show similarity with human pseudohypoparathyroidism type Ia, a disease caused by an inactivating heterozygous mutation of the stimulatory G protein α subunit from the maternal genome that induces multiple hormone resistance and that courses with a syndrome called Albright hereditary osteodystrophy. Naturally occurring pseudohypoparathyroidism in animals has been reported previously only in a ferret.

  7. Fault Zone Resistivity Structure and Monitoring at the Taiwan Chelungpu Drilling Project (TCDP

    Directory of Open Access Journals (Sweden)

    Chih-Wen Chiang

    2008-01-01

    Full Text Available The Taiwan Chelungpu-fault drilling project (TCDP has undertaken scientific drilling and directly sampled the sub-surface rupture of the 1999 Chi-Chi earthquake. Audio-magnetotelluric (AMT measurements were used to investigate electrical resistivity structure at the TCDP site from 2004 - 2006. These data show a geoelectric strike direction of N15°E to N30°E. Inversion and forward modeling of the AMT data were used to generate a 1-D resistivity model that has a prominent low resistivity zone (< 10 ohm-m between depths of 1100 and 1500 m. When combined with porosity measurements, theAMT measurements imply that the ground water has a resistivity of 0.55 ohm-m at the depth of the fault zone.

  8. Deep electrical resistivity structure of Costa Rican Subduction Zone

    Science.gov (United States)

    Worzewski, T.; Jegen, M.; Brasse, H.; Taylor, W.

    2009-04-01

    The water content and its distribution play an important role in the subduction process. Water is released from the subducting slab in a series of metamorphic reactions and the hydration of the mantle wedge may trigger the onset of melting, weakening and changes in the dynamics and thermal structure of subduction zones. However, the amount of water carried into the subduction zone and its distribution are not well constrained by existing data and are subject of vigorous current research in SFB574 (Volatiles and Fluids in Subduction Zones: Climate Feedback and Trigger Mechanisms for Natural Disasters). We will show numerical modeling studies which are used to determine the resolution and sensitivity of the MT response to fluids in the crust and subducting slab under the special condition of a coastal setting. In 2007-2008 we conducted a long-period magnetotelluric investigations in northwestern Costa Rica on- and offshore, where the Cocos Plate subducts beneath the Carribean plate. Eleven marine magnetotelluric Stations newly developed and constructed by IFM-GEOMAR and University of Kiel were deployed on the 200 km long marine extension of the profile for several months. We will present the data and its processing, as well as our attempts to eliminate motion induced noise observed on some stations on the cliffy shelf due to tidal waves hitting the shelf and trench parallel- and perpendicular currents. The marine profile was extended landwards by the Free University of Berlin over length of 160 kilometers with further 18 stations. We present preliminary modeling results of land data, which revealed interesting features, inter alia a possible image of fluid release from the downgoing slab in the forearc, as well as ongoing modeling of the combined on- and offshore data sets.

  9. Moving Aerospace Structural Design Practice to a Load and Resistance Factor Approach

    Science.gov (United States)

    Larsen, Curtis E.; Raju, Ivatury S.

    2016-01-01

    Aerospace structures are traditionally designed using the factor of safety (FOS) approach. The limit load on the structure is determined and the structure is then designed for FOS times the limit load - the ultimate load. Probabilistic approaches utilize distributions for loads and strengths. Failures are predicted to occur in the region of intersection of the two distributions. The load and resistance factor design (LRFD) approach judiciously combines these two approaches by intensive calibration studies on loads and strength to result in structures that are efficient and reliable. This paper discusses these three approaches.

  10. Identification of glycan structure alterations on cell membrane proteins in desoxyepothilone B resistant leukemia cells.

    Science.gov (United States)

    Nakano, Miyako; Saldanha, Rohit; Göbel, Anja; Kavallaris, Maria; Packer, Nicolle H

    2011-11-01

    Resistance to tubulin-binding agents used in cancer is often multifactorial and can include changes in drug accumulation and modified expression of tubulin isotypes. Glycans on cell membrane proteins play important roles in many cellular processes such as recognition and apoptosis, and this study investigated whether changes to the glycan structures on cell membrane proteins occur when cells become resistant to drugs. Specifically, we investigated the alteration of glycan structures on the cell membrane proteins of human T-cell acute lymphoblastic leukemia (CEM) cells that were selected for resistance to desoxyepothilone B (CEM/dEpoB). The glycan profile of the cell membrane glycoproteins was obtained by sequential release of N- and O-glycans from cell membrane fraction dotted onto polyvinylidene difluoride membrane with PNGase F and β-elimination respectively. The released glycan alditols were analyzed by liquid chromatography (graphitized carbon)-electrospray ionization tandem MS. The major N-glycan on CEM cell was the core fucosylated α2-6 monosialo-biantennary structure. Resistant CEM/dEpoB cells had a significant decrease of α2-6 linked sialic acid on N-glycans. The lower α2-6 sialylation was caused by a decrease in activity of β-galactoside α2-6 sialyltransferase (ST6Gal), and decreased expression of the mRNA. It is clear that the membrane glycosylation of leukemia cells changes during acquired resistance to dEpoB drugs and that this change occurs globally on all cell membrane glycoproteins. This is the first identification of a specific glycan modification on the surface of drug resistant cells and the mechanism of this downstream effect on microtubule targeting drugs may offer a route to new interventions to overcome drug resistance.

  11. Blast-Resistant Improvement of Sandwich Armor Structure with Aluminum Foam Composite

    Directory of Open Access Journals (Sweden)

    Shu Yang

    2013-01-01

    Full Text Available Sandwich armor structures with aluminum foam can be utilized to protect a military vehicle from harmful blast load such as a landmine explosion. In this paper, a system-level dynamic finite element model is developed to simulate the blast event and to evaluate the blast-resistant performance of the sandwich armor structure. It is found that a sandwich armor structure with only aluminum foam is capable of mitigating crew injuries under a moderate blast load. However, a severe blast load causes force enhancement and results in much worse crew injury. An isolating layer between the aluminum foam and the vehicle floor is introduced to remediate this drawback. The results show that the blast-resistant capability of the innovative sandwich armor structure with the isolating layer increases remarkably.

  12. Electronic structure, excitation properties, and chemical transformations of extreme ultra-violet resist materials

    Science.gov (United States)

    Rangan, Sylvie; Bartynski, Robert A.; Narasimhan, Amrit; Brainard, Robert L.

    2017-07-01

    The electronic structure of extreme ultra violet resist materials and of their individual components, two polymers and two photoacid generators (PAGs), is studied using a combination of x-ray and UV photoemission spectroscopies, electron energy loss spectroscopy, and ab-initio techniques. It is shown that simple molecular models can be used to understand the electronic structure of each sample and describe the experimental data. Additionally, effects directly relevant to the photochemical processes are observed: low energy loss processes are observed for the phenolic polymer containing samples that should favor thermalization of electrons; PAG segregation is measured at the surface of the resist films that could lead to surface inhomogeneities; both PAGs are found to be stable upon irradiation in the absence of the polymer, contrasting with a high reactivity that can be followed upon x-ray irradiation of the full resist.

  13. Structures of Two New Flavonoids and Effects of Licorice Phenolics on Vancomycin-Resistant Enterococcus Species

    Directory of Open Access Journals (Sweden)

    Eerdunbayaer

    2014-03-01

    Full Text Available Since our previous study revealed that several licorice phenolics have antibacterial effects on methicillin-resistant Staphylococcus aureus (MRSA, and suppressive effects on the oxacillin resistance of MRSA, we further investigated effectiveness of licorice constituents on vancomycin-resistant Enterococcus (VRE bacteria, and purified 32 phenolic compounds. Two flavonoids among them were characterized structurally, and identified their structures as demethylglycyrol (31 and 5,7-di-O-methylluteone (32, respectively. Examination of antibacterial effects of licorice phenolics showed that 3-arylcoumarins such as licoarylcoumarin (9 and glycycoumarin (26, and 2-arylcoumarones such as gancaonin I (17, have moderate to potent antibacterial effects on the VRE strains used in this study.

  14. Process for improving the corrosion resistance of zirconium alloy structure parts

    International Nuclear Information System (INIS)

    Hanneman, R.E.; Urquhart, A.W.; Vermilyea, D.A.

    1976-01-01

    A process is described for improving the corrosion resistance of zirconium alloy structure parts in the environment of BWR type reactors. It comprises the production on the structure parts of an adhesive film consisting of electron conducting and chemically inert materials in the conditions prevailing in the BWR type reactors. The film can be made of Au, Ag, Pt, Ni, Cr, Fe or Nb [fr

  15. A study of cross-bridge kelvin resistor structures for reliable measurement of low contact resistances

    NARCIS (Netherlands)

    Stavitski, N.; Klootwijk, J.H.; van Zeijl, H.W.; Kovalgin, Alexeij Y.; Wolters, Robertus A.M.

    2008-01-01

    The parasitic factors that strongly influence the measurement accuracy of Cross-Bridge Kelvin Resistor (CBKR) structures for low specific contact resistances (�?c) have been extensively discussed during last few decades and the minimum of the �?c value, which could be accurately extracted, was

  16. Structure Analysis Of Corrosion Resistant Thermal Sprayed Coatings On Low Alloy Steels

    Science.gov (United States)

    Chaliampalias, D.; Vourlias, G.; Pistofidis, N.; Pavlidou, E.; Stergiou, A.; Stergioudis, G.; Polychroniadis, E. K.

    2007-04-01

    Metallic coatings have been proved to reduce the rate of corrosion of steel in various atmospheres. In this work the structure of Al, Cu-Al and Zn thermal sprayed coatings is examined. The as formed coatings are extremely rough, and they are composed of several phases which increase corrosion resistance as it was determined Salt Spray Chamber tests.

  17. Role of masonry infill in seismic resistant resistance of RC structures

    International Nuclear Information System (INIS)

    Taher, Salah El-Din F.; Afefy, Hamdy Mohy El-Din

    2008-01-01

    The influence of partial masonry infilling on the seismic lateral behavior of low, medium and high rise buildings is addressed. The most simple equivalent frame system with reduced degrees of freedom is proposed for handling multi-story multi-bay infilled frames. The system is composed of a homogenized continuum for the reinforced concrete members braced with unilateral diagonal struts for each bay, which are only activated in compression. Identification of the equivalent characteristics and nonlinear material properties is accomplished from the concepts of inverse analysis, along with statistical tests of the hypotheses, employed to establish the appropriate filtering scheme and the proper accuracy tolerance. The suggested system allows for nonlinear finite element static and dynamic analysis of sophisticated infilled reinforced concrete frames. Sensitivity analysis is undertaken to check the suitability of the proposed system to manipulate various structural applications. The effect of number of stories, number of bays, infill proportioning and infill locations are investigated. Geometric and material nonlinearity of both infill panel and reinforced concrete frame are considered in the nonlinear finite element analysis. Energy consideration using modified Rayleigh's method is employed to figure out the response parameters under lateral dynamic excitations. The results reflect the significance of infill in increasing the strength, stiffness and frequency of the entire system depending on the position and amount of infilling. Lower infilling is noted to provide more stiffness for the system as compared with upper locations. (author)

  18. Mechanism and structural diversity of exoribonuclease-resistant RNA structures in flaviviral RNAs

    NARCIS (Netherlands)

    Macfadden, Andrea; O’Donoghue, Zoe; Silva, Patricia A.G.C.; Chapman, Erich G.; Olsthoorn, René C.; Sterken, Mark G.; Pijlman, Gorben P.; Bredenbeek, Peter J.; Kieft, Jeffrey S.

    2018-01-01

    Flaviviruses such as Yellow fever, Dengue, West Nile, and Zika generate disease-linked viral noncoding RNAs called subgenomic flavivirus RNAs. Subgenomic flavivirus RNAs result when the 5′–3′ progression of cellular exoribonuclease Xrn1 is blocked by RNA elements called Xrn1-resistant RNAs located

  19. Structure and function of ABCG2-rich extracellular vesicles mediating multidrug resistance.

    Directory of Open Access Journals (Sweden)

    Vicky Goler-Baron

    2011-01-01

    Full Text Available Multidrug resistance (MDR is a major impediment to curative cancer chemotherapy. The ATP-Binding Cassette transporters ABCG2, ABCB1 and ABCC2 form a unique defense network against multiple structurally and functionally distinct chemotherapeutics, thereby resulting in MDR. Thus, deciphering novel mechanisms of MDR and their overcoming is a major goal of cancer research. Recently we have shown that overexpression of ABCG2 in the membrane of novel extracellular vesicles (EVs in breast cancer cells results in mitoxantrone resistance due to its dramatic sequestration in EVs. However, nothing is known about EVs structure, biogenesis and their ability to concentrate multiple antitumor agents. To this end, we here found that EVs are structural and functional homologues of bile canaliculi, are apically localized, sealed structures reinforced by an actin-based cytoskeleton and secluded from the extracellular milieu by the tight junction proteins occludin and ZO-1. Apart from ABCG2, ABCB1 and ABCC2 were also selectively targeted to the membrane of EVs. Moreover, Ezrin-Radixin-Moesin protein complex selectively localized to the border of the EVs membrane, suggesting a key role for the tethering of MDR pumps to the actin cytoskeleton. The ability of EVs to concentrate and sequester different antitumor drugs was also explored. Taking advantage of the endogenous fluorescence of anticancer drugs, we found that EVs-forming breast cancer cells display high level resistance to topotecan, imidazoacridinones and methotrexate via efficient intravesicular drug concentration hence sequestering them away from their cellular targets. Thus, we identified a new modality of anticancer drug compartmentalization and resistance in which multiple chemotherapeutics are actively pumped from the cytoplasm and highly concentrated within the lumen of EVs via a network of MDR transporters differentially targeted to the EVs membrane. We propose a composite model for the structure and

  20. Resistivity structures imaging using time-domain electromagnetic data; TDEM ho ni yoru chika hiteiko kozo no imaging

    Energy Technology Data Exchange (ETDEWEB)

    Noguchi, K. [Waseda University, Tokyo (Japan). School of Science and Engineering; Endo, M. [Waseda University, Tokyo (Japan)

    1996-10-01

    The kernel function for transient vertical magnetic dipole was defined for semi-infinite uniform medium, and the 1-D imaging algorithm by TDEM (time-domain electromagnetic) method was developed for underground resistivity structure. Electromagnetic migration method directly images sectional resistivity profiles from the data observed by frequency-domain MT method, and determines underground resistivity profiles by integral equation of MT field using the concept of return travel time in reflection seismic exploration. The method reported in this paper is also one of the EM migration methods. The imaging algorithm of 2-D resistivity structure was developed by correcting 1-D imaging in consideration of the effect of 2-D anomaly on 1-D imaging (the resistivity of anomaly can be obtained from the resistivity contrast between anomaly and medium). The conventional methods require enormous forward computation, while this method can obtain underground resistivity structure in extremely short computation time, resulting in superior practicability. 12 refs., 7 figs.

  1. The role of fluid in the growth of fibrous diamond: a study of African and Canadian coated diamonds

    OpenAIRE

    Tomlinson, E. L.

    2006-01-01

    This multi-disciplinary study determines the composition and structure of mantle fluid inclusions in natural fibrous diamonds, and their role in diamond growth. Coated diamonds from Mbuji Mayi (Democratic Republic of Congo) and Panda (Canada) were analysed by electron microprobe, laser ablation inductively coupled mass spectrometry and infrared spectroscopy. Carbonate and KC1 are important components of the complex fluid. Therefore, KCI-K2CO3 was used as a solvent catalyst for graphite in hig...

  2. Structural insights into the quinolone resistance mechanism of Mycobacterium tuberculosis DNA gyrase.

    Directory of Open Access Journals (Sweden)

    Jérémie Piton

    Full Text Available Mycobacterium tuberculosis DNA gyrase, an indispensable nanomachine involved in the regulation of DNA topology, is the only type II topoisomerase present in this organism and is hence the sole target for quinolone action, a crucial drug active against multidrug-resistant tuberculosis. To understand at an atomic level the quinolone resistance mechanism, which emerges in extensively drug resistant tuberculosis, we performed combined functional, biophysical and structural studies of the two individual domains constituting the catalytic DNA gyrase reaction core, namely the Toprim and the breakage-reunion domains. This allowed us to produce a model of the catalytic reaction core in complex with DNA and a quinolone molecule, identifying original mechanistic properties of quinolone binding and clarifying the relationships between amino acid mutations and resistance phenotype of M. tuberculosis DNA gyrase. These results are compatible with our previous studies on quinolone resistance. Interestingly, the structure of the entire breakage-reunion domain revealed a new interaction, in which the Quinolone-Binding Pocket (QBP is blocked by the N-terminal helix of a symmetry-related molecule. This interaction provides useful starting points for designing peptide based inhibitors that target DNA gyrase to prevent its binding to DNA.

  3. Resistive MHD reconstruction of two-dimensional coherent structures in space

    Directory of Open Access Journals (Sweden)

    W.-L. Teh

    2010-11-01

    Full Text Available We present a reconstruction technique to solve the steady resistive MHD equations in two dimensions with initial inputs of field and plasma data from a single spacecraft as it passes through a coherent structure in space. At least two components of directly measured electric fields (the spacecraft spin-plane components are required for the reconstruction, to produce two-dimensional (2-D field and plasma maps of the cross section of the structure. For convenience, the resistivity tensor η is assumed diagonal in the reconstruction coordinates, which allows its values to be estimated from Ohm's law, E+v×B=η·j. In the present paper, all three components of the electric field are used. We benchmark our numerical code by use of an exact, axi-symmetric solution of the resistive MHD equations and then apply it to synthetic data from a 3-D, resistive, MHD numerical simulation of reconnection in the geomagnetic tail, in a phase of the event where time dependence and deviations from 2-D are both weak. The resistivity used in the simulation is time-independent and localized around the reconnection site in an ellipsoidal region. For the magnetic field, plasma density, and pressure, we find very good agreement between the reconstruction results and the simulation, but the electric field and plasma velocity are not predicted with the same high accuracy.

  4. Soil Structure Evaluation Across Geologic Transition Zones Using 2D Electrical Resistivity Imaging Technique

    Directory of Open Access Journals (Sweden)

    Geraldine C Anukwu

    2017-06-01

    Full Text Available This study utilizes the electrical resistivity values obtained using 2-D Electrical resistivity imaging (ERI technique to evaluate the subsurface lithology across different geological units. The primary objective was to determine the effect of subsurface lithology on the integrity of a road pavement, which had developed cracks and potholes at various locations. The dipole-dipole configuration was utilized and a total of nine traverses were established in the study area, whose geology cuts across both the basement and sedimentary complexes. The inverted resistivity section obtained showed significant variation in resistivity along established traverses and also across the different rock units, with the resistivity value ranging from about 4 ohm-m to greater than 7000 ohm- m. The lithology as interpreted from the resistivity section revealed the presence topsoil, clay, sandy clay, sand, sand stones/basement rocks, with varying vertical and horizontal arrangements to a depth of 40m. Results suggest that the geologic sequence and structure might have contributed to the observed pavement failure. The capability of the 2D ERI as an imaging tool is observed, especially across the transition zones as depicted in this study. The study further stressed the ability of this technique if properly designed and implemented, to be capable of providing a wealth of information that could complement other traditional geotechnical and geologic techniques.

  5. Development of chitosan-tripolyphosphate non-woven fibrous scaffolds for tissue engineering application.

    Science.gov (United States)

    Pati, Falguni; Adhikari, Basudam; Dhara, Santanu

    2012-04-01

    The fibrous scaffolds are promising for tissue engineering applications because of their close structural resemblance with native extracellular matrix. Additionally, the chemical composition of scaffold is also an important consideration as they have significant influences on modulating cell attachment, morphology and function. In this study, chitosan-tripolyphosphate (TPP) non-woven fibrous scaffolds were prepared through wetspinning process. Interestingly, at physiological pH these scaffolds release phosphate ions, which have significant influences on cellular function. For the first time, cell viability in presence of varying concentration of sodium TPP solution was analyzed and correlated with the phosphate release from the scaffolds during 30 days incubation period. In vitro degradation of the chitosan-TPP scaffolds was higher than chitosan scaffolds, which may be due to decrease in crystallinity as a result of instantaneous ionic cross-linking during fiber formation. The scaffolds with highly interconnected porous structure present a remarkable cytocompatibility for cell growing, and show a great potential for tissue engineering applications.

  6. Effect of crystals and fibrous network polymer additives on cellular morphology of microcellular foams

    Science.gov (United States)

    Miyamoto, Ryoma; Utano, Tatsumi; Yasuhara, Shunya; Ishihara, Shota; Ohshima, Masahiro

    2015-05-01

    In this study, the core-back foam injection molding was used for preparing microcelluar polypropylene (PP) foam with either a 1,3:2,4 bis-O-(4-methylbenzylidene)-D-sorbitol gelling agent (Gel-all MD) or a fibros network polymer additive (Metablen 3000). Both agent and addiive could effectively control the celluar morphology in foams but somehow different ways. In course of cooling the polymer with Gel-all MD in the mold caity, the agent enhanced the crystal nucleation and resulted in the large number of small crystals. The crystals acted as effective bubble nucleation agent in foaming process. Thus, the agent reduced the cell size and increased the cell density, drastically. Furthermore, the small crystals provided an inhomogenuity to the expanding cell wall and produced the high open cell content with nano-scale fibril structure. Gell-all as well as Metablene 3000 formed a gel-like fibrous network in melt. The network increased the elongational viscosity and tended to prevent the cell wall from breaking up. The foaming temperature window was widened by the presence of the network. Especially, the temperature window where the macro-fibrous structure was formed was expanded to the higher temperature. The effects of crystal nucleating agent and PTFE on crystals' size and number, viscoelsticity, rheological propreties of PP and cellular morphology were compared and thorougly investigated.

  7. Extraction of uranium from sea water by means of fibrous complex adsorbents

    International Nuclear Information System (INIS)

    Miyamatsu, Tokuhisa; Oguchi, Noboru; Kanchiku, Yoshihiko; Aoyagi, Takanobu

    1982-01-01

    Fibrous complex adsorbents for uranium extraction from sea water were prepared by introducing titanic acid or basic zinc carbonate as effective constituents into fibrous ion exchangers. A fibrous chelate type adsorbent was also tested. Among the adsorbents examined, the following ones demonstrated excellent properties for the recovery of uranium from sea water. a) A fibrous, weakly acidic cation exchanger was treated with titanyl sulfate in aqueous sulfuric acid solution, which was followed by neutralization to afford a fibrous adsorbent containing titanic acid (QC-1f(Ti)). The adsorption capacity for uranium in sea water was estimated by extrapolation to be 50μg-U/g-Ad or 1170 μg-U/g-Ti. b) A fibrous, strongly acidic cation exchanger was treated in a similar way to afford another type of fibrous adsorbent with titanic acid incorporated (QCS-Ti). The adsorption capacity was estimated by extrapolation to be 20-30 μg-U/g-Ad. (author)

  8. Carbon fiber polymer-matrix structural composites for electrical-resistance-based sensing

    Science.gov (United States)

    Wang, Daojun

    This dissertation has advanced the science and technology of electrical-resistance-based sensing of strain/stress and damage using continuous carbon fiber epoxy-matrix composites, which are widely used for aircraft structures. In particular, it has extended the technology of self-sensing of carbon fiber polymer-matrix composites from uniaxial longitudinal loading and flexural loading to uniaxial through-thickness loading and has extended the technology from structural composite self-sensing to the use of the composite (specifically a one-lamina composite) as an attached sensor. Through-thickness compression is encountered in the joining of composite components by fastening. Uniaxial through-thickness compression results in strain-induced reversible decreases in the through-thickness and longitudinal volume resistivities, due to increase in the fiber-fiber contact in the through-thickness direction, and minor-damage-induced irreversible changes in these resistivities. The Poisson effect plays a minor role. The effects in the longitudinal resistivity are small compared to those in the through-thickness direction, but longitudinal resistance measurement is more amenable to practical implementation in structures than through-thickness resistance measurement. The irreversible effects are associated with an increase in the through-thickness resistivity and a decrease in the longitudinal resistivity. The through-thickness gage factor is up to 5.1 and decreases with increasing compressive strain above 0.2%. The reversible fractional change in through-thickness resistivity per through-thickness strain is up to 4.0 and decreases with increasing compressive strain. The irreversible fractional change in through-thickness resistivity per unit through-thickness strain is around -1.1 and is independent of the strain. The sensing is feasible by measuring the resistance away from the stressed region, though the effectiveness is less than that at the stressed region. A one

  9. Fibrous and textile materials for composite applications

    CERN Document Server

    Fangueiro, Raul

    2016-01-01

    This book focuses on the fibers and textiles used in composite materials. It presents both existing technologies currently used in commercial applications and the latest advanced research and developments. It also discusses the different fiber forms and architectures, such as short fibers, unidirectional tows, directionally oriented structures or advanced 2D- and 3D-textile structures that are used in composite materials. In addition, it examines various synthetic, natural and metallic fibers that are used to reinforce polymeric, cementitious and metallic matrices, as well as fiber properties, special functionalities, manufacturing processes, and composite processing and properties. Two entire chapters are dedicated to advanced nanofiber and nanotube reinforced composite materials. The book goes on to highlight different surface treatments and finishes that are applied to improve fiber/matrix interfaces and other essential composite properties. Although a great deal of information about fibers and textile str...

  10. Zygomaticomaxillary complex fracture in a zygomatic bone affected by monostotic fibrous dysplasia: a very rare association.

    Science.gov (United States)

    Pinto, Lara Carolina D'Araújo; Ribeiro, André Luis Ribeiro; Aquime, João Rafael Habib Souza; Carreira, Aline Semblano Dias; Alves-Junior, Sérgio M; Pinheiro, João J V

    2013-05-01

    The association between fibrous dysplasia (FD) and fractures is very rare. This paper reports the case of a zygomaticomaxillary complex fracture in a bone affected by FD, a 29-year-old man who was involved in a bicycle accident and who subsequently presented with a zygomaticomaxillary complex fracture. Computed tomography revealed multiple fractures of the left zygomaticomaxillary complex with dysplastic bone alterations. Fracture lines occurred near transitional areas between the lesion and healthy bone. The patient was treated through an intraoral approach by an open reduction and internal fixation procedure, using a titanium miniplate and screws. An incisional biopsy was performed through the maxillary sinus to confirm the diagnosis of FD. After 12 months of follow-up, there were no postoperative complications. This paper reports a rare association thought to be caused by irregular trabecular bone deposition, which increases bone thickness/resiliency and thus increases its clinical fracture resistance.

  11. Use of thermal imaging in characterization of ceramic fiber structures

    International Nuclear Information System (INIS)

    Järveläinen, Matti; Keskinen, Lassi; Levänen, Erkki

    2013-01-01

    Fibrous bodies that contain open porosity can have a very heterogeneous structure that is difficult to characterize in terms of local flow resistance changes within the same sample. This article presents a method that is applicable for a quick analysis of flow distribution even with large samples. In this first attempt to understand how our flow distribution thermal imaging works, we present how the measuring parameters and the results correlate with sample's thickness and density. The results indicate that our method can quickly make a distinction between areas that have different flow resistances because of variations in the sample's density or wall thickness

  12. Fabrication of gelatin-siloxane fibrous mats via sol-gel and electrospinning procedure and its application for bone tissue engineering

    International Nuclear Information System (INIS)

    Ren Lei; Wang Jun; Yang Fangyu; Wang Lin; Wang Dong; Wang Tianxiao; Tian Miaomiao

    2010-01-01

    Our strategy is to design and fabricate biomimetic and bioactive scaffolds that resemble the native extracellular matrix as closely as possible so as to create conducive living milieu that will induce cell to function naturally. In the present study, gelatin/siloxane (GS) hybrids were prepared by a sol-gel processing, and electrospinning technique was used to fabricate GS fibrous mats to support the growth of bone marrow-derived mesenchymal stem cells (BMSCs) for tissue engineering of bone. The results indicate that the porous structure and fiber size of the GS fibrous mats can be fine tuned by varying the viscosity of GS precursor solution. Additionally, the Ca 2+ -containing GS fibrous mats biomimetically deposited apatite in a simulated body fluid (SBF), as well as stimulating its BMSCs proliferation and differentiation in vitro, thereby dignifying its in vitro bioactivity.

  13. A giant cranial aneurysmal bone cyst associated with fibrous dysplasia.

    Science.gov (United States)

    Składzieriń, J; Olés, K; Zagólski, O; Moskała, M; Sztuka, M; Strek, P; Wierzchowski, W; Tomik, J

    2008-01-01

    An aneurysmal bone cyst (ABC) is a rare, benign fibro-osseous lesion, considered a vascular phenomenon secondary to fibrous dysplasia or a giant-cell tumour, and occurs mainly in long bones and vertebrae. In this case report a 16-year-old male presented with massive epistaxis. He was admitted with a 3-year history of chronic rhinitis, headaches, right ocular pain and recurrent epistaxis. CT scans showed a predominantly cystic, expansive mass obstructing both nasal cavities, extending to all paranasal sinuses and both orbits, with evidence of anterior cranial fossa skull base destruction. The patient underwent a craniofacial resection of the tumour performed with an external approach and an immediate reconstruction of the dural defect. Histology confirmed the lesion was an ABC associated with fibrous dysplasia. The patient's recovery was complete. A large facial aneurysmal bone cyst can damage the facial skeleton and skull base, and requires excision by a combined external approach.

  14. Spontaneous involution of diffuse fibrous dysplasia of paranasal sinuses.

    Science.gov (United States)

    De Carlo, D; Zotto, L Dal; Carollo, C; Porzionato, A; D'Avella, D; Pomerri, F; Battistella, P A

    2015-05-01

    We report the case of a 25-year-old patient, diagnosed at age 10, with diffuse fibrous dysplasia of the paranasal sinuses, an extremely rare idiopathic condition. This diagnosis is possible only by cerebral computed tomography (CT), cerebral and anterior skull base magnetic resonance imaging (MRI), and histopathology. Surgical treatment is common. This boy had mild symptoms: moderate headache in the morning that did not affect his daily activity, and rhinitis, partially responsive to medication. The neurologic examination was abnormal. Radiographs, CT, and MRI showed a diffuse mass in the paranasal sinuses which had a histopathological diagnosis of fibrous dysplasias. The family refused to refer the patient to surgery. The boy has been monitored annually for 15 years. He has remained asymptomatic without headache since age 11, with normal, general and neurologic examinations. Serial MRIs showed a spontaneous partial involution of the mass. © The Author(s) 2014.

  15. Aging-caused changes in optical anisotropy of fibrous tissues

    Science.gov (United States)

    Mikhailova, Alyona D.; Ermolenko, Sergey B.; Zimnyakov, Dmitry A.; Angelsky, Oleg V.

    2009-10-01

    Energy density approach as a modification of the coherent potential approximation was applied to analyze the influence of aging-caused changes in the fibrous tissue on its birefringence. The real fibrous tissue such as tendon was modeled by disordered array of partially oriented dielectric cylinders illuminated by a normally incident linearly polarized plane wave. The supraspinatus human tendon was taken as an object for theoretical modeling. The morphological features of the studied tissue were considered for a system of collagen fiber bundles embedded in a carbohydrate matrix. The latter one is a mixture of glycosaminoglycans and proteoglycans. Age-caused changes of the fibers and matrix influence on the spectral dependence of optical anisotropy spectrum.

  16. Multilayer Impregnated Fibrous Thermal Insulation Tiles

    Science.gov (United States)

    Tran, Huy K.; Rasky, Daniel J.; Szalai, Christine e.; Hsu, Ming-ta; Carroll, Joseph A.

    2007-01-01

    The term "secondary polymer layered impregnated tile" ("SPLIT") denotes a type of ablative composite-material thermal- insulation tiles having engineered, spatially non-uniform compositions. The term "secondary" refers to the fact that each tile contains at least two polymer layers wherein endothermic reactions absorb considerable amounts of heat, thereby helping to prevent overheating of an underlying structure. These tiles were invented to afford lighter-weight alternatives to the reusable thermal-insulation materials heretofore variously used or considered for use in protecting the space shuttles and other spacecraft from intense atmospheric-entry heating.

  17. Comparative Study of Wear Resistance of the Composite with Microhybrid Structure and Nanocomposite

    Directory of Open Access Journals (Sweden)

    Pieniak Daniel

    2016-12-01

    Full Text Available The aim of the study was to compare microhardness and wear resistance of ceramic-polymer composites with micro and nano-hybrid structure. For the studies commercial composites were used, containing filler particles of the same type but different sizes, nano-sized (Filtek Ultimate and micro-sized (Filtek Z250 composites. Tribological testing was conducted using ball-on-disc micro-tribometer. Vickers testing method was applied for microhardness studies with the use of Futertech FM 700 device. It has been demonstrated that the wear of Filtek Ultimate is almost twice lower in comparison to wear of Filtek Z250 composite. It has been concluded that the use of filler nanoparticles significantly increased wear resistance of the material. Additionally, lack of correlation between material microhardness and wear resistance has been demonstrated.

  18. Crystal structure and electrical resistivity studies of Gd(Fe1-x Cox)2 intermetallics

    International Nuclear Information System (INIS)

    Onak, M.; Guzdek, P.; Stoch, P.; Chmist, J.; Bednarski, M.; Panta, A.; Pszczola, J.

    2007-01-01

    From X-ray analysis (295 K) it was found that the cubic, MgCu 2 -type, Fd3m crystal structure appears across the Gd(Fe 1-x Co x ) 2 series. Electrical resistivity measurements for the Gd(Fe 1-x Co x ) 2 intermetallics were performed in a wide temperature region and the parameters characterizing the resistivity dependence on temperature and composition were determined. The differential of the electrical resistivity against temperature was used to estimate Curie temperatures. The Curie temperature versus x, high and moderately increasing in the iron-rich area, rapidly drops in the cobalt-rich region. The obtained results are compared with the data known for the Dy(Fe 1-x Co x ) 2 series. The Curie temperature is related to both the number of 3d electrons and the de Gennes factor

  19. Malignant fibrous histiocytoma of pancreas: presentation of a case

    International Nuclear Information System (INIS)

    Garcia Sanchez, M.A.; Serrano Gotarredona, M.P.; Fernandez-Cruz, J.; Marrero Calvo, S.

    1995-01-01

    We present a case of malignant fibrous histiocytoma (MFH) located in the body and tail of the pancreas of a 60-year-old woman. The mass was large, lobulated and well delimited by a pseudocapsule. Pancreatectomy involving the body and tail and splenectomy were performed and the diagnosis was reached on the basis of pathological and immunohistochemical studies. The course was aggressive with local recurrence and liver metastases presenting two months after the operation. The computerized tomography (CT) findings are provided. (Author)

  20. Characteristics of sinonasal fibrous dysplasia: experience from a single department.

    Science.gov (United States)

    Duan, Chen; Dai, Qi; Liu, Quan; Yu, Hongmeng

    2018-01-01

    We summarized the characteristics of fibrous dysplasia patients in our department to obtain clinical data on this disease. We retrospectively reviewed 28 patients who were diagnosed with sinonasal fibrous dysplasia based on pathological examination results from March 2012 to February 2017 in our department. The 28 patients included 16 females and 12 males, and the median age was 31.5 (range, 7-69) years. The three most common symptoms were nasal obstruction (25%), impaired vision (21%) and headache (18%). Most of the tumors were located in the sphenoid sinus (50%), nasal cavity (39%) or ethmoid sinus (36%). The surgical strategy included an exclusive endoscopic approach (25 cases) and an endoscopic approach combined with sublabial incision (three cases). The median follow-up period was 29 months (range, 3-62 months), and three patients were lost to follow-up. Two of the remaining 25 patients developed recurrence. However, since the second surgery, there has been no recurrence to date. Our study indicates that the treatment of fibrous dysplasia patients should be tailored according to patient and disease characteristics. The main surgical procedure is the endoscopic approach, and the effect is good. Although the recurrence rate is low, follow-up is necessary.

  1. Feed Technology of Fibrous Sugarcane Residues for Ruminants

    Directory of Open Access Journals (Sweden)

    Kuswandi

    2007-06-01

    Full Text Available Abundant sugarcane residue during shortage of roughage in dry season gives an opportunity to raise ruminants around sugarcane industries. However, these products are not widely used by farmers due to an assumption that the usage is inefficient and that the feed utilization technology is not widely recognized. Sugarcane fibrous residues (tops, bagasse and pith may be a potential feed component if pre-treated to increase its digestion and consumption by the animal, and/or supplemented by other ingredients to balance nutrients in the rumen as well as those for production purpose. Digestibility can be increased by chemical treatments such as ammoniation and other alkaline treatments, whereas consumption can be increased by physical treatments such as grinding, hammermilling or pelleting. Nutrients that are missing in these fibrous residues can be provided by addition of urea, molasses and minerals for maintenance need, and bypass nutrients (carbohydrates, protein and fats that are digested in the small intestine and available for tissue or milk synthesis. There are three options for development of livestock agribusiness based on fibrous sugarcane residues; however, these require several technologies to optimize the utilization of these residues.

  2. Growth performance and behaviour in grouped pigs fed fibrous diet.

    Science.gov (United States)

    Bakare, A G; Madzimure, J; Ndou, S P; Chimonyo, M

    2014-08-01

    The objective of the study was to investigate the effect of feeding fibrous diets on growth performance and occurrence of aggressive behaviours in growing pigs. Sixty healthy castrated pigs (initial body weight: 46.7±4.35 kg) were used. A basal diet was diluted with maize cobs to two levels (0 and 160 g/kg dry matter). Behavioural activities were observed using video cameras for three weeks, 8 h/d starting at 0800 h. Pigs subjected to control diet gained more weight compared to pigs receiving fibrous diet in week 1 (0.47 vs 0.15 kg, respectively) and 2 (1.37 vs 1.04, respectively) (pdiet in the third week. Pigs on high fibrous spent more time eating, lying down, standing, walking and fighting (pdiet. Time spent eating increased as the weeks progressed whilst time spent lying down decreased. Time of day had an effect on time spent on different behavioural activities exhibited by all pigs on different treatment diet (pdiet had more skin lesions in all body regions compared to pigs on control diet (pdiet with maize cobs did not affect growth performance and also did not reduce aggressive behaviours. Aggressive behaviours emanated out of frustration when queuing on the feeder. The findings of this study suggest that maize cobs can be included at a level of 160 g/kg in diets of pigs. However, to reduce the level of aggression more feeding space should be provided.

  3. Escherichia coli Population Structure and Antibiotic Resistance at a Buffalo/Cattle Interface in Southern Africa.

    Science.gov (United States)

    Mercat, Mathilde; Clermont, Olivier; Massot, Méril; Ruppe, Etienne; de Garine-Wichatitsky, Michel; Miguel, Eve; Valls Fox, Hugo; Cornelis, Daniel; Andremont, Antoine; Denamur, Erick; Caron, Alexandre

    2015-12-28

    At a human/livestock/wildlife interface, Escherichia coli populations were used to assess the risk of bacterial and antibiotic resistance dissemination between hosts. We used phenotypic and genotypic characterization techniques to describe the structure and the level of antibiotic resistance of E. coli commensal populations and the resistant Enterobacteriaceae carriage of sympatric African buffalo (Syncerus caffer caffer) and cattle populations characterized by their contact patterns in the southern part of Hwange ecosystem in Zimbabwe. Our results (i) confirmed our assumption that buffalo and cattle share similar phylogroup profiles, dominated by B1 (44.5%) and E (29.0%) phylogroups, with some variability in A phylogroup presence (from 1.9 to 12%); (ii) identified a significant gradient of antibiotic resistance from isolated buffalo to buffalo in contact with cattle and cattle populations expressed as the Murray score among Enterobacteriaceae (0.146, 0.258, and 0.340, respectively) and as the presence of tetracycline-, trimethoprim-, and amoxicillin-resistant subdominant E. coli strains (0, 5.7, and 38%, respectively); (iii) evidenced the dissemination of tetracycline, trimethoprim, and amoxicillin resistance genes (tet, dfrA, and blaTEM-1) in 26 isolated subdominant E. coli strains between nearby buffalo and cattle populations, that led us (iv) to hypothesize the role of the human/animal interface in the dissemination of genetic material from human to cattle and toward wildlife. The study of antibiotic resistance dissemination in multihost systems and at anthropized/natural interface is necessary to better understand and mitigate its multiple threats. These results also contribute to attempts aiming at using E. coli as a tool for the identification of pathogen transmission pathway in multihost systems. Copyright © 2016, American Society for Microbiology. All Rights Reserved.

  4. Structural fire resistance experimental research priority needs of U.S. industry

    CERN Document Server

    Almand, Kathleen H

    2012-01-01

    Structural Fire Resistance Experimental Research – Priority Needs of U.S. Industry provides a synthesis of stakeholder input to a prioritized agenda for research at the National Fire Research Laboratory (NFRL) at the National Institute of Standards and Technology (NIST) designed to accelerate the implementation of performance-based fire engineering for structures. The NFRL presents a broad range of unanswered questions regarding the performance of real structures in fire conditions, and informs performance-based design methods and standards in this field. The authors conducted a comprehensive literature review of large-scale structural fire testing and compiled research needs from a variety of sources. The book addresses major issues of broad concern in the fire community, such as real fire exposure and structural response, composite floor system performance, enhancing modeling performance, and understanding the embedded safety features in design methods. It concludes with a prioritized set of research reco...

  5. Buried Man-made Structure Imaging using 2-D Resistivity Inversion

    Science.gov (United States)

    Anderson Bery, Andy; Nordiana, M. M.; El Hidayah Ismail, Noer; Jinmin, M.; Nur Amalina, M. K. A.

    2018-04-01

    This study is carried out with the objective to determine the suitable resistivity inversion method for buried man-made structure (bunker). This study was carried out with two stages. The first stage is suitable array determination using 2-D computerized modeling method. One suitable array is used for the infield resistivity survey to determine the dimension and location of the target. The 2-D resistivity inversion results showed that robust inversion method is suitable to resolve the top and bottom part of the buried bunker as target. In addition, the dimension of the buried bunker is successfully determined with height of 7 m and length of 20 m. The location of this target is located at -10 m until 10 m of the infield resistivity survey line. The 2-D resistivity inversion results obtained in this study showed that the parameters selection is important in order to give the optimum results. These parameters are array type, survey geometry and inversion method used in data processing.

  6. Resistivity Structures of the Chelungpu Fault in the Taichung Area, Taiwan

    Directory of Open Access Journals (Sweden)

    Ping-Hu Cheng

    2006-01-01

    Full Text Available We conducted magnetotelluric prospecting in the Taichung area to investigate subsurface resistivity structures of the Chelungpu fault and the resistivity of rock formations. The results indicate that the Chelungpu fault is a complex fault system consisting of two major fault zones, several fracture zones, and back thrust. The two major fault zones, the basal and the Chi-Chi fault zone are about 800 m apart on the ground and converge to a narrow band at a depth of 3000 m. The fault zones are not smooth, composed of ramps and platforms with an average eastward dipping angle of 35° - 37° within the depth of 3000 m. In the shallower region, the basal fault zone has developed along the boundary of the Toukoshan Formation (resistivity: 200 - 400 Ω-m at the footwall and the Neogene formations on the hanging wall, where the Cholan Formation, the Chinshiu Shale, and the Kueichulai Formation have respective resistivity mainly in the ranges: 40 - 100, 8 - 60, and 50 - 150 Ω-m. While the Chi-Chi fault zone has developed along the weak layers of the Cholan Formation where resistivity is lower than the unsheared block.

  7. Improved Bevirimat resistance prediction by combination of structural and sequence-based classifiers

    Directory of Open Access Journals (Sweden)

    Dybowski J Nikolaj

    2011-11-01

    Full Text Available Abstract Background Maturation inhibitors such as Bevirimat are a new class of antiretroviral drugs that hamper the cleavage of HIV-1 proteins into their functional active forms. They bind to these preproteins and inhibit their cleavage by the HIV-1 protease, resulting in non-functional virus particles. Nevertheless, there exist mutations in this region leading to resistance against Bevirimat. Highly specific and accurate tools to predict resistance to maturation inhibitors can help to identify patients, who might benefit from the usage of these new drugs. Results We tested several methods to improve Bevirimat resistance prediction in HIV-1. It turned out that combining structural and sequence-based information in classifier ensembles led to accurate and reliable predictions. Moreover, we were able to identify the most crucial regions for Bevirimat resistance computationally, which are in line with experimental results from other studies. Conclusions Our analysis demonstrated the use of machine learning techniques to predict HIV-1 resistance against maturation inhibitors such as Bevirimat. New maturation inhibitors are already under development and might enlarge the arsenal of antiretroviral drugs in the future. Thus, accurate prediction tools are very useful to enable a personalized therapy.

  8. Host population structure and treatment frequency maintain balancing selection on drug resistance

    Science.gov (United States)

    Baskerville, Edward B.; Colijn, Caroline; Hanage, William; Fraser, Christophe; Lipsitch, Marc

    2017-01-01

    It is a truism that antimicrobial drugs select for resistance, but explaining pathogen- and population-specific variation in patterns of resistance remains an open problem. Like other common commensals, Streptococcus pneumoniae has demonstrated persistent coexistence of drug-sensitive and drug-resistant strains. Theoretically, this outcome is unlikely. We modelled the dynamics of competing strains of S. pneumoniae to investigate the impact of transmission dynamics and treatment-induced selective pressures on the probability of stable coexistence. We find that the outcome of competition is extremely sensitive to structure in the host population, although coexistence can arise from age-assortative transmission models with age-varying rates of antibiotic use. Moreover, we find that the selective pressure from antibiotics arises not so much from the rate of antibiotic use per se but from the frequency of treatment: frequent antibiotic therapy disproportionately impacts the fitness of sensitive strains. This same phenomenon explains why serotypes with longer durations of carriage tend to be more resistant. These dynamics may apply to other potentially pathogenic, microbial commensals and highlight how population structure, which is often omitted from models, can have a large impact. PMID:28835542

  9. High-resolution structure of the antibiotic resistance protein NimA from Deinococcus radiodurans

    International Nuclear Information System (INIS)

    Leiros, Hanna-Kirsti S.; Tedesco, Consiglia; McSweeney, Seán M.

    2008-01-01

    In this paper, the 1.2 Å atomic resolution crystal structure of the 5-nitroimidazole antibiotic resistance protein NimA from Deinococcus radiodurans (DrNimA) is presented. Many anaerobic human pathogenic bacteria are treated using 5-nitroimidazole-based (5-Ni) antibiotics, a class of inactive prodrugs that contain a nitro group. The nitro group must be activated in an anaerobic one-electron reduction and is therefore dependent on the redox system in the target cells. Antibiotic resistance towards 5-Ni drugs is found to be related to the nim genes (nimA, nimB, nimC, nimD, nimE and nimF), which are proposed to encode a reductase that is responsible for converting the nitro group of the antibiotic into a nonbactericidal amine. A mechanism for the Nim enzyme has been proposed in which two-electron reduction of the nitro group leads to the generation of nontoxic derivatives and confers resistance against these antibiotics. The cofactor was found to be important in the mechanism and was found to be covalently linked to the reactive His71. In this paper, the 1.2 Å atomic resolution crystal structure of the 5-nitroimidazole antibiotic resistance protein NimA from Deinococcus radiodurans (DrNimA) is presented. A planar cofactor is clearly visible and well defined in the electron-density map adjacent to His71, the identification of the cofactor and its properties are discussed

  10. Development of rational design technique for frame steel structure combining seismic resistance and economic performance

    International Nuclear Information System (INIS)

    Kato, Motoki; Morishita, Kunihiro; Shimono, Masaki; Chuman, Yasuharu; Okafuji, Takashi; Monaka, Toshiaki

    2015-01-01

    Anti-seismic designs have been applied to plant support steel frames for years. Today, a rational structure that further improves seismic resistance and ensures economic performance is required in response to an increase of seismic load on the assumption of predicted future massive earthquakes. For satisfying this requirement, a steel frame design method that combines a steel frame weight minimizing method, which enables economic design through simultaneous minimization of multiple steel frame materials, and a seismic response control design technology that improves seismic resistance has been established. Its application in the design of real structures has been promoted. This paper gives an overview of this design technology and presents design examples to which this design technology is applied. (author)

  11. General Concerns Life-Cycle Design of Economical Ice-Resistant Structures in the Bohai Sea

    Directory of Open Access Journals (Sweden)

    Zhang Da-yong

    2017-08-01

    Full Text Available In China, the oil and natural gas resources of Bohai Bay are mainly marginal oil fields. It is necessary to build both iceresistant and economical offshore platforms. However, there are many risks during the life cycle of offshore platforms due to the imperfect preliminary design for the Bohai Sea economical ice-resistant structures. As a result, the whole life-cycle design should be considered, including plan, design, construction, management and maintenance design. Based on the demand of existing codes and research of the basic design, structural ice-resistant performance and the reasonable management and maintenance, the life-cycle design theory is discussed. It was concluded that the life-cycle cost-effective optimum design proposed will lead to a minimum risk.

  12. Structure and electrical resistivity of alkali-alkali and lithium-based liquid binary alloys

    International Nuclear Information System (INIS)

    Mishra, A.K.; Mukherjee, K.K.

    1990-01-01

    Harmonic model potential, developed and used for simple metals is applied here to evaluate hardsphere diameters, which ensure minimum interionic pair potential for alkali-alkali (Na-K, Na-Rb, Na-Cs, K-Rb, K-Cs) and lithium-based (Li-Na, Li-Mg, Li-In, Li-Tl) liquid binary alloys as a function of composition for use in the determination of their partial structure factors. These structure factors are then used to calculate electrical resistivities of alloys considered. The computed values of electrical resistivity as a function of composition agree both, in magnitude and gradient reasonably well with experimental values in all cases except in Cs systems, where the disagreement is appreciable. (author)

  13. Microphase Separation Controlled beta-Sheet Crystallization Kinetics in Fibrous Proteins

    International Nuclear Information System (INIS)

    Hu, X.; Lu, Q.; Kaplan, D.; Cebe, P.

    2009-01-01

    Silk is a naturally occurring fibrous protein with a multiblock chain architecture. As such, it has many similarities with synthetic block copolymers, including the possibility for e-sheet crystallization restricted within the crystallizable blocks. The mechanism of isothermal crystallization kinetics of e-sheet crystals in silk multiblock fibrous proteins is reported in this study. Kinetics theories, such as Avrami analysis which was established for studies of synthetic polymer crystal growth, are for the first time extended to investigate protein self-assembly in e-sheet rich Bombyx mori silk fibroin samples, using time-resolved Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC) and synchrotron real-time wide-angle X-ray scattering (WAXS). The Avrami exponent, n, was close to 2 for all methods and crystallization temperatures, indicating formation of e-sheet crystals in silk proteins is different from the 3-D spherulitic crystal growth found in synthetic polymers. Observations by scanning electron microscopy support the view that the protein structures vary during the different stages of crystal growth, and show a microphase separation pattern after chymotrypsin enzyme biodegradation. We present a model to explain the crystallization of the multiblock silk fibroin protein, by analogy to block copolymers: crystallization of e-sheets occurs under conditions of geometrical restriction caused by phase separation of the crystallizable and uncrystallizable blocks. This crystallization model could be widely applicable in other proteins with multiblock (i.e., crystallizable and noncrystallizable) domains.

  14. Developing a technique to enhance durability of fibrous ion-exchange resin substrate for space greenhouses

    Science.gov (United States)

    Krivobok, A. S.; Berkovich, Yu. A.; Shcherbakova, V. A.; Chuvilskaya, N. A.

    2018-02-01

    One way to cut consumables for space plant growth facilities (PGF) with artificial soil in the form of fibrous ion-exchange resin substrate (FIERS) is on-board regeneration of the used medium. After crop harvest the procedure includes removal of the roots from the fibrous media with preservation of the exchanger properties and capillary structure. One type of FIERS, namely BIONA-V3ۛ, has been used in Russian prototypes of space conveyors. We describe a two-stage treatment of BIONA-V3ۛ including primary microwave heating of the used FIERS until (90 ± 5) °C in alkali-peroxide solution during 3.5 hrs. The second stage of the treatment is decomposition of root vestiges inside pores of BIONA-V3ۛ by using thermophilic and mesophilic anaerobic bacteria Clostridium thermocellum, Clostridium cellulolyticum and Cellulosilyticum lentocellum during 7-10 days at 55 °C. The two-stage procedure allows extraction of 90% dead roots from the FIERS' pores and the preservation of root zone hydro-physical properties. A posterior enrichment of the FIERS by minerals makes BIONA- V3ۛ reusable.

  15. Direct E-jet printing of three-dimensional fibrous scaffold for tendon tissue engineering.

    Science.gov (United States)

    Wu, Yang; Wang, Zuyong; Ying Hsi Fuh, Jerry; San Wong, Yoke; Wang, Wilson; San Thian, Eng

    2017-04-01

    Tissue engineering (TE) offers a promising strategy to restore diseased tendon tissue. However, a suitable scaffold for tendon TE has not been achieved with current fabrication techniques. Herein, we report the development of a novel electrohydrodynamic jet printing (E-jetting) for engineering 3D tendon scaffold with high porosity and orientated micrometer-size fibers. The E-jetted scaffold comprised tubular multilayered micrometer-size fibrous bundles, with interconnected spacing and geometric anisotropy along the longitudinal direction of the scaffold. Fiber diameter, stacking pattern, and interfiber distance have been observed to affect the structural stability of the scaffold, of which the enhanced mechanical strength can be obtained for scaffolds with thick fibers as the supporting layer. Human tenocytes showed a significant increase in cellular metabolism on the E-jetted scaffolds as compared to that on conventional electrospun scaffolds (2.7-, 2.8-, and 3.1-fold increase for 150, 300, and 600 µm interfiber distance, respectively; p 3D fibrous scaffold to promote organized tissue reconstruction for potential tendon healing. © 2015 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 616-627, 2017. © 2015 Wiley Periodicals, Inc.

  16. Demonstration of Corrosion-Resistant Hybrid Composite Bridge Beams for Structural Applications

    Science.gov (United States)

    2016-09-01

    severity. Although the steel coupon testing resulted in a C2 classification , the results were on the upper limit of the category. The potential for...suggest the Fort Knox Bridge #4 site is a Category 3 classification of atmospheric corrosion severity. Although the steel coupon testing re- sulted in a...result of corrosion of the steel support structures or the reinforcing bar in the concrete. The application of corrosion-resistant technology can

  17. Drug resistance and population structure of M.tuberculosis isolates from prisons and communities in Ethiopia.

    Science.gov (United States)

    Ali, Solomon; Beckert, Patrick; Haileamlak, Abraham; Wieser, Andreas; Pritsch, Michael; Heinrich, Norbert; Löscher, Thomas; Hoelscher, Michael; Niemann, Stefan; Rachow, Andrea

    2016-11-21

    The population structure and drug resistance pattern of Mycobacterium tuberculosis complex (MTBC) isolates in Ethiopian prisons and some communities is still unknown. A comparative cross sectional study was conducted on 126 MTBC strains isolated from prisons and communities in southwestern, southern and eastern Ethiopia. Phenotypic drug susceptibility testing was performed with the MGIT960 system. Combined 24-loci Mycobacterium interspersed repetitive unit-variable number tandem repeat and spacer oligonucleotide typing methods were used to study the MTBC population structure. The obtained data from prisons and communities were compared using statistical tests and regression analysis. A diverse population structure with 11 different lineages and sub-lineages was identified. The predominant strains were the recently described Ethiopia_H37Rv like (27.52%) and Ethiopia_3 (16.51%) with equal lineage distribution between prisons and communities. 28.57% of prison strains and 31.82% of community strains shared the identical genotype with at least one other strain. The multidrug-resistance (MDR) prevalence of the community was 2.27% whereas that of prisons was 9.52%. The highest mono resistance was seen against streptomycin (15.89%). Tuberculosis in communities and prisons is caused by a variety of MTBC lineages with predominance of local Ethiopian lineages. The increasing prevalence of MDR MTBC strains is alarming. These findings suggest the need for new approaches for control of MDR tuberculosis in Ethiopia.

  18. Amorphous metal formulations and structured coatings for corrosion and wear resistance

    Science.gov (United States)

    Farmer, Joseph C [Tracy, CA

    2011-12-13

    A system for coating a surface comprising providing a source of amorphous metal that contains more than 11 elements and applying the amorphous metal that contains more than 11 elements to the surface by a spray. Also a coating comprising a composite material made of amorphous metal that contains more than 11 elements. An apparatus for producing a corrosion-resistant amorphous-metal coating on a structure comprises a deposition chamber, a deposition source in the deposition chamber that produces a deposition spray, the deposition source containing a composite material made of amorphous metal that contains more than 11 elements, and a system that directs the deposition spray onto the structure.

  19. Analysis of Structure and Deformation Mechanisms of Mineral Wool Slabs under Compression

    Directory of Open Access Journals (Sweden)

    Laimutis STEPONAITIS

    2012-06-01

    Full Text Available The products of mineral wool are widely used for thermal insulation of buildings, both at construction of new buildings and at renovation of old ones. The mechanical resistance and stability of them, as well as their energy saving and heat saving requirements are in most cases related to the essential specifications of the building. The mechanical characteristics of these products are subject to structure of material, density, content of binder in the product and to technology of production. Subject to the latter, mineral wool products with different fibrous structure are received, therefore, for the structure of each type, the individual structural models are developed attempting to describe the properties of fibrous systems. The deformability of mineral wool products is conditioned by mobility of fibrous structure, which shows up best under compression by short term loads. This study established the impact of various thicknesses and deformations on changes in structure of rock wool products. It also established that the thickness of mineral wool products conditions and influences considerable changes in their structure.DOI: http://dx.doi.org/10.5755/j01.ms.18.2.1926

  20. A highly resistant structure between cuticle and cortex of human hair.

    Science.gov (United States)

    Takahashi, T; Yoshida, S

    2017-06-01

    To clarify the presence and properties of a unique structure which is located between the cuticle and cortex of human hair. Whole hair fibre and longitudinally split hair were used. Treated with a mixture of urea, reductant and alkaline, hair was split at the interface between cuticle and cortex. The residues in the solution were observed by microscope, and the distribution of lipids and protein was determined. From the treated longitudinally split hair, a membrane-like structure which was located at the interface between cuticle and cortex was obtained. This structure showed especially high resistance against chemical treatment and was thought to be the region into which the proximal roots of the cuticle cells are embedded. It was supposed that some steryl glucoside-like lipid, of which the presence in the cuticle and cortex interface was previously reported, is located in this structure. This study proposed the presence of a membrane-like structure, which is highly resistant against chemical treatment, at the region between cuticle and cortex of human hair. This may protect cortex from external stimuli more firmly than the surface part of cuticle. © 2016 Society of Cosmetic Scientists and the Société Française de Cosmétologie.

  1. Design feasibility study of a divertor component reinforced with fibrous metal matrix composite laminate

    Energy Technology Data Exchange (ETDEWEB)

    You, J.-H. [Max-Planck-Institut fuer Plasmaphysik, EURATOM Association, Boltzmannstr. 2, D-85748 Garching (Germany)]. E-mail: j.h.you@ipp.mpg.de

    2005-01-01

    Fibrous metal matrix composites possess advanced mechanical properties compared to conventional alloys. It is expected that the application of these composites to a divertor component will enhance the structural reliability. A possible design concept would be a system consisting of tungsten armour, copper composite interlayer and copper heat sink where the composite interlayer is locally inserted into the highly stressed domain near the bond interface. For assessment of the design feasibility of the composite divertor concept, a non-linear multi-scale finite element analysis was performed. To this end, a micro-mechanics algorithm was implemented into a finite element code. A reactor-relevant heat flux load was assumed. Focus was placed on the evolution of stress state, plastic deformation and ductile damage on both macro- and microscopic scales. The structural response of the component and the micro-scale stress evolution of the composite laminate were investigated.

  2. Design feasibility study of a divertor component reinforced with fibrous metal matrix composite laminate

    International Nuclear Information System (INIS)

    You, J.-H.

    2005-01-01

    Fibrous metal matrix composites possess advanced mechanical properties compared to conventional alloys. It is expected that the application of these composites to a divertor component will enhance the structural reliability. A possible design concept would be a system consisting of tungsten armour, copper composite interlayer and copper heat sink where the composite interlayer is locally inserted into the highly stressed domain near the bond interface. For assessment of the design feasibility of the composite divertor concept, a non-linear multi-scale finite element analysis was performed. To this end, a micro-mechanics algorithm was implemented into a finite element code. A reactor-relevant heat flux load was assumed. Focus was placed on the evolution of stress state, plastic deformation and ductile damage on both macro- and microscopic scales. The structural response of the component and the micro-scale stress evolution of the composite laminate were investigated

  3. Association Between Insulin Resistance and Bone Structure in Nondiabetic Postmenopausal Women

    Science.gov (United States)

    Finkelstein, Joel S.; Bouxsein, Mary L.; Yu, Elaine W.

    2016-01-01

    Context: The clinical consequences of insulin resistance and hyperinsulinemia on bone remain largely unknown. Objective: The objective of the study was to evaluate the effect of insulin resistance on peripheral bone geometry, volumetric bone mineral density (vBMD), bone microarchitecture, and estimated bone strength. Design, Setting, and Participants: This cross-sectional study included 146 postmenopausal, nondiabetic Caucasian women (mean age 60.3 ± 2.7 y) who were participating in the Study of Women's Health Across the Nation. Interventions: There were no interventions. Main Outcome Measures: High-resolution peripheral quantitative computed tomography was used to assess bone density and microstructure at the distal radius and tibia. Fasting insulin and glucose were measured and insulin resistance was estimated using homeostasis model assessment of insulin resistance (HOMA-IR), with higher values indicating greater insulin resistance. Results: There was a negative association between HOMA-IR and bone size and a positive association between HOMA-IR and total vBMD, trabecular vBMD, trabecular thickness, and cortical thickness at the radius and tibia. These relationships remained, even after adjusting for body weight and other potential covariates (eg, time since menopause, cigarette smoking, physical activity, prior use of osteoporosis medications or glucocorticoids). Conclusions: In nondiabetic, postmenopausal women, insulin resistance was associated with smaller bone size, greater volumetric bone mineral density, and generally favorable bone microarchitecture at weight-bearing and nonweight-bearing skeletal sites. These associations were independent of body weight and other potential covariates, suggesting that hyperinsulinemia directly affects bone structure independent of obesity and may explain, in part, the higher trabecular bone density and favorable trabecular microarchitecture seen in individuals with type 2 diabetes mellitus. PMID:27243136

  4. Formulae for predicting non-acoustical parameters of deformed fibrous porous materials.

    Science.gov (United States)

    Hirosawa, Kunikazu; Nakagawa, Hiroshi

    2017-06-01

    Formulae to predict non-acoustical parameters (i.e., flow resistivity, tortuosity, and viscous and thermal characteristic lengths) of deformed fibrous porous materials are proposed provided that the original values of these parameters are known in advance. These formulae are developed using numerical fluid analyses. The flow resistivity was calculated by using the finite element method for a two-dimensional incompressible viscous fluid approximated by Oseen flow. The tortuosity and characteristic lengths were calculated by using the complex variable boundary element method for a two-dimensional potential flow. These calculations showed that the flow resistivity was inversely proportional to the porosity multiplied by the three-halves power of the compression ratio, that the tortuosity can be represented by a linear expression of the porosity, and that both characteristic lengths changed in the same manner with respect to the porosity. These tendencies agreed well with measurements of real glass wools of various bulk densities. The proposed prediction formulae for the parameters were then derived from the tendencies obtained from the numerical analyses. The predicted parameter values were compared with the calculated parameters and good agreement was obtained, confirming the validity of the proposed formulae.

  5. The anti-Staphylococcus aureus activity of the phenanthrene fraction from fibrous roots of Bletilla striata.

    Science.gov (United States)

    Guo, Jing-Jing; Dai, Bin-Ling; Chen, Ni-Pi; Jin, Li-Xia; Jiang, Fu-Sheng; Ding, Zhi-Shan; Qian, Chao-Dong

    2016-11-29

    Bletillae Rhizoma, the tuber of Bletilla striata, has been used in Chinese traditional medicine to treat infectious diseases. Chemical studies indicated that phenanthrene was one of the most important components of the herb, with a broad spectrum of antibiotic activity against Gram-positive bacteria. The objective of this study was to further characterize the antibacterial activity of the phenanthrene fraction from the fibrous root of the pseudobulb of B. striata. The phenanthrene fraction (EF60) from the ethanol extract of fibrous roots of Bletilla striata pseudobulbs was isolated using polyamide column chromatography. The antibacterial activity of the fraction was evaluated in vitro using a 96-well microtiter plate and microbroth dilution method. The cytotoxicity of EF60 against mammalian cells was tested by hemolysis and MTT assays. EF60 was obtained using alcohol extraction and polyamide column chromatography, with a yield of 14.9 g per 1 kg of the fibrous roots of B. striata. In vitro tests indicated that EF60 was active against all tested strains of Staphylococcus aureus, including clinical isolates and methicillin-resistant S. aureus (MRSA). The minimum inhibitory concentration (MIC) values of EF60 against these pathogens ranged from 8 to 64 μg/mL. Minimum bactericidal concentration tests demonstrated that EF60 was bactericidal against S. aureus 3304 and ATCC 29213 and was bacteriostatic against S. aureus 3211, ATCC 25923, and ATCC 43300. Consistently, the time-kill assay indicated that EF60 could completely kill S. aureus ATCC 29213 at 2× the MIC within 3 h but could kill less than two logarithmic units of ATCC 43300, even at 4× the MIC within 24 h. The postantibiotic effects (PAE) of EF60 (4× MIC) against strains 29213 and 43300 were 2.0 and 0.38 h, respectively. Further studies indicated that EF60 (160 μg/mL) showed no cytotoxicity against human erythrocytes, and was minimally toxic to Human Umbilical Vein Endothelial Cells with an IC 50 of 75

  6. Honey-based PET or PET/chitosan fibrous wound dressings: effect of honey on electrospinning process.

    Science.gov (United States)

    Arslan, Aysu; Simşek, Murat; Aldemir, Sevcan Dalkıranoğlu; Kazaroğlu, Nur Merve; Gümüşderelioğlu, Menemşe

    2014-07-01

    In this study, fibrous mats were fabricated via electrospinning from solutions of polyethylene terephthalate (PET), PET/chitosan, and PET/honey at different concentrations. The effect of honey and chitosan on electrospinning process was investigated and compared. Fibers containing chitosan had a beaded or ribbon-like/branched morphology, but this morphology improved in the presence of honey. The diameter of electrospun fibers decreased with an increased ratio of honey in PET solution. In addition, fiber deposition area in the collector increased by increasing the honey content. PET/chitosan and PET/honey fibrous mats reached an equilibrium water content in 15 min and their water uptake capacities, which are important for exudating wounds, were found in the range of 280-430% on dry basis. Cytotoxicity evaluation demonstrated that fibers exhibited no cytotoxic activity. This study discloses that PET fibrous mats especially electrospun in the presence of honey could be proposed as potential wound dressing materials owing to their improved processing abilities besides their suitable structural properties.

  7. Morphology and In Vitro Behavior of Electrospun Fibrous Poly(D,L-lactic acid for Biomedical Applications

    Directory of Open Access Journals (Sweden)

    Toshihiro Inami

    2013-01-01

    Full Text Available This work describes the fabrication, optimization, and characterization of electrospun fibrous poly(D,L-lactic acid (PDLLA for biomedical applications. The influences of the polymer concentration of the electrospinning solution (5, 10, or 15 wt% and the solution flow rate (0.1, 0.5, 1.0, or 2.0 mL/h on the morphology of the obtained fibrous PDLLA were evaluated. The in vitro biocompatibility of two types of PDLLA, ester terminated PDLLA (PDLLA-R and carboxyl terminated PDLLA (PDLLA-COOH, was evaluated by monitoring apatite formation on samples immersed in Hanks’ balanced salt (HBS solution. 15 wt% polymer solution was the most beneficial for preparing a fibrous PDLLA structure. Meanwhile, no differences in morphology were observed for PDLLA prepared at various flow rates. Apatite precipitate is formed on both types of PDLLA only 1 day after immersion in HBS solution. After 7 days of immersion, PDLLA-COOH showed greater apatite formation ability compared with that of PDLLA-R, as measured by thin-film X-ray diffraction. The results indicated that the carboxyl group is effective for apatite precipitation in the body environment.

  8. PTFE-nanocomposites structure and wear-resistance changing in various methods of structural modification

    Science.gov (United States)

    Mashkov, Yu K.; Ruban, A. S.; Rogachev, E. A.; Chemisenko, O. V.

    2018-01-01

    Conditions of polymer materials usage containing nanoelements as modifiers significantly affect the requirements for their physic-mechanical and tribological properties. However, the mechanisms of nanoparticles effect to the polymers tribotechnical properties have not been studied enough. The article aim is to analyze the results of studying polytetrafluoroethylene modified with cryptocrystalline graphite and silicon dioxide and to determine the effectiveness of the modification methods used and methods for further improving filled PTFE mechanical and tribotechnical properties. The effect of modifiers to PCM supramolecular structure was analyzed with SEM methods. The results of modifying the PCM samples surface by depositing a copper film with ion-vacuum deposition methods and changing the structural-phase composition and tribological characteristics are considered. The findings make possible to characterize the physicochemical processes under frictional interaction in metal polymer tribosystems.

  9. Structural Insights into the Fluoroquinolone Resistance Mechanism of Shigella flexneri DNA Gyrase and Topoisomerase IV.

    Science.gov (United States)

    Tamanna; Ramana, Jayashree

    2016-07-01

    Traveler's diarrhea (TD) is an important public health concern that can result from a variety of intestinal pathogens, including bacteria, parasites, and virus. A number of antibiotics are being used to cure TD, but due to widespread use of these antibiotics, the pathogens are becoming resistant to them. In this work, we performed docking studies of DNA gyraseA (GyrA) and topoisomerase IV (ParC) of Shigella flexneri and their mutants with two different fluoroquinolones, ciprofloxacin and norfloxacin, to understand their resistance mechanism at the structural level. S. flexneri strains with mutations at serine 83 to leucine and aspartic acid 87 to glutamate or asparagine of GyrA and that of serine 80 to isoleucine in ParC have decreased susceptibility to fluoroquinolones. This analysis revealed that interaction of ciprofloxacin/norfloxacin with all the mutants was weaker than the interaction of ciprofloxacin/norfloxacin with the wild type. This study highlights the importance of aspartic acid and serine in GyrA and that of serine in ParC, forming bonds with ciprofloxacin/norfloxacin, which may play a crucial role in antibiotic resistance. This work corelates very well with the experimental outcomes and gives a good explanation for fluoroquinolone resistance in S. flexneri.

  10. Electrospun fibrous mats with conjugated tetraphenylethylene and mannose for sensitive turn-on fluorescent sensing of Escherichia coli.

    Science.gov (United States)

    Zhao, Long; Chen, Yufei; Yuan, Jiang; Chen, Maohua; Zhang, Hong; Li, Xiaohong

    2015-03-11

    A rapid and sensitive detection of microbes in water and biological fluids is a key requirement in water and food safety, environmental monitoring, and clinical diagnosis and treatment. In the current study, electrospun polystyrene-co-maleic anhydride (PSMA) fibers with conjugated mannose and tetraphenylethylene (TPE) were developed for Escherichia coli (E. coli) detection, taking advantage of the high grafting capabilities of ultrafine fibers and the highly porous structure of the fibrous mat to entrap bacterial cells. The specific binding between mannose grafts on PSMA fibers and FimH proteins from the fimbriae of E. coli led to an efficient "turn-on" profile of TPE due to the aggregation-induced emission (AIE) effect. Poly(ethylene glycol) diamine was used as hydrophilic tethers to increase the conformational mobility of mannose grafts, indicating a more sensitive change in the fluorescence intensity against bacteria concentrations, a lower fluorescence background of fibers without bacteria incubation, and a sufficient space for bacteria binding, compared with the use of hexamethylenediamine or poly(ethylene imine) as spacers for mannose grafting. The addition of bovine serum albumin, glucose, or both of them into bacteria suspensions showed no significant changes in the fluorescence intensity of fibrous mats, indicating the anti-interference capability against these proteins and saccharides. An equation was drafted of the fluorescence intensities of fibrous mats against E. coli concentrations ranging from 10(2) to 10(5) CFU/mL. The test strip format was established on mannose-conjugated PSMA fibers after exposure to E. coli of different concentrations, providing a potential tool with a visual sensitivity of bacteria concentrations as low as 10(2) CFU/mL in a matter of minutes. This strategy may offer a capacity to be expanded to exploit electrospun fibrous mats and other carbohydrate-cell interactions for bioanalysis and biosensing of pathogenic bacteria.

  11. The impact of a freshwater fish farm on the community of tetracycline-resistant bacteria and the structure of tetracycline resistance genes in river water.

    Science.gov (United States)

    Harnisz, Monika; Korzeniewska, Ewa; Gołaś, Iwona

    2015-06-01

    The aim of this study was to assess the impact of a fish farm on the structure of antibiotic resistant bacteria and antibiotic resistance genes in water of Drwęca River. Samples of upstream river waters; post-production waters and treated post-production waters from fish farm; as well as downstream river waters were monitored for tetracycline resistant bacteria, tetracycline resistant genes, basic physico-chemical parameters and tetracyclines concentration. The river waters was characterized by low levels of pollution, which was determined based on water temperature, pH and concentrations of dissolved oxygen and tetracycline antibiotics. Culture-dependent (heterotrophic plate counts, counts of bacteria resistant to oxytetracycline (OTC(R)) and doxycycline (DOX(R)), minimum inhibitory concentrations for oxytetracycline and doxycycline, multidrug resistance of OTC(R) and DOX(R), qualitative composition of OTC(R) and DOX(R), prevalence of tet genes in resistant isolates) and culture-independent surveys (quantity of tet gene copies) revealed no significant differences in the abundance of antibiotic-resistant bacteria and antibiotic resistance genes between the studied samples. The only way in which the fish farm influenced water quality in the Drwęca River was by increasing the diversity of tetracycline-resistance genes. However, it should also be noted that the bacteria of the genera Aeromonas sp. and Acinetobacter sp. were able to transfer 6 out of 13 tested tet genes into Escherichiacoli, which can promote the spread of antibiotic resistance in the environment. Copyright © 2015 Elsevier Ltd. All rights reserved.

  12. Influence of mutations in some structural genes of heat-shock proteins on radiation resistance of Escherichia coli

    International Nuclear Information System (INIS)

    Verbenko, V.N.; Kuznetsova, L.V.; Bikineeva, E.G.; Kalinin, V.L.

    1992-01-01

    Lethal effects of γ-irradiation were studied in Escherichia coli strains with normal repair genotype and in radiation-resistant Gam r strains, both carrying additional mutations in the structural genes dnaK, grpE, groES or groEL. The null mutation ΔdnaK52::Cm r enhanced radiation sensitivity of wild-type cells and abolished the effect of heat induced rediation-resistance (ETIRR) and elevated radiation resistance of the Gam r strains

  13. Chromium-modified a-C films with advanced structural, mechanical and corrosive-resistant characteristics

    Energy Technology Data Exchange (ETDEWEB)

    Ming, Miao Yi [International Chinese-Belarusian scientific laboratory on vacuum-plasma technology, Nanjing University of Science and Technology, Nanjing 210094 (China); Francisk Skorina Gomel State University, Gomel 246019 (Belarus); Jiang, Xiaohong, E-mail: jxh0668@sina.com [International Chinese-Belarusian scientific laboratory on vacuum-plasma technology, Nanjing University of Science and Technology, Nanjing 210094 (China); Francisk Skorina Gomel State University, Gomel 246019 (Belarus); Piliptsou, D.G., E-mail: pdg_@mail.ru [International Chinese-Belarusian scientific laboratory on vacuum-plasma technology, Nanjing University of Science and Technology, Nanjing 210094 (China); Francisk Skorina Gomel State University, Gomel 246019 (Belarus); Zhuang, Yuzhao; Rogachev, A.V.; Rudenkov, A.S. [International Chinese-Belarusian scientific laboratory on vacuum-plasma technology, Nanjing University of Science and Technology, Nanjing 210094 (China); Francisk Skorina Gomel State University, Gomel 246019 (Belarus); Balmakou, A. [Faculty of Material Science and Technology, Slovak University of Technology, Trnava 91724 (Slovakia)

    2016-08-30

    Highlights: • Influence of the chromium interlayer on the structure and mechanical properties of a-C:Cr films. • Residual stress and wear of a-C:Cr and Cr/a-C varies due to their phase and surface morphology. • Chromium-modified a-C films with advanced structural, mechanical and corrosive-resistant characteristics. - Abstract: To improve structural, mechanical and chemical properties of diamond-like carbon films, we developed amorphous carbon chromium-modified composite films fabricated by means of cathode magnetic filtered arc deposition. The properties were analyzed by Raman spectroscopy, X-ray photoelectron spectroscopy and atomic force microscopy for the purpose of the structure characterization, elemental analysis and topology examination. Moreover, we also assessed residual stress, the coefficient of friction, hardness, the elastic modulus and corrosion parameters through X-ray double-crystal surface profilometry, tribo-testing, nanoindenter-testing, as well as contact angle measurements and potentiodynamic polarization analysis. As a result of a comparative analysis, we revealed a substantial improvement in the characteristics of developed composite films in comparison with amorphous carbon films. For example, Cr-modification is resulted, in greater integrated performance, toughness and corrosion resistance; the residual stress was reduced substantially.

  14. Influence of polymer structure on plasma-polymer interactions in resist materials

    Science.gov (United States)

    Bruce, Robert Lawson

    The controlled patterning of polymer resists by plasma plays an essential role in the fabrication of integrated circuits and nanostructures. As the dimensions of patterned structures continue to decrease, we require an atomistic understanding underlying the morphological changes that occur during plasma-polymer interactions. In this work, we investigated how plasma surface modifications and the initial polymer structure influenced plasma etch behavior and morphological changes in polymer resists. Using a prototypical argon discharge, we observed polymer modification by ions and vacuum ultraviolet (VUV) radiation from the plasma. A thin, highly dense modified layer was formed at the polymer surface due to ion bombardment. The thickness and physical properties of this ion-damaged layer was independent of polymer structure for the systems examined here. A relationship was observed that strongly suggests that buckling caused by ion-damaged layer formation on a polymer is the origin of roughness that develops during plasma etching. Our results indicate that with knowledge of the mechanical properties of the ion-damaged layer and the polymer being processed, plasma-induced surface roughness can be predicted and the surface morphology calculated. Examining a wide variety of polymer structures, the polymer poly(4-vinylpyridine) (P4VP) was observed to produce extremely smooth surfaces during high-ion energy plasma etching. Our data suggest that VUV crosslinking of P4VP below the ion-damaged layer may prevent wrinkling. We also studied another form of resists, silicon-containing polymers that form a SiO2 etch barrier layer during O2 plasma processing. In this study, we examined whether assisting SiO2 layer formation by adding Si-O bonds to the polymer structure would improve O2 etch behavior and reduce polymer surface roughness. Our results showed that while adding Si-O bonds decreased etch rates and silicon volatilization during O2 plasma exposure, the surface roughness

  15. Embolism resistance of three boreal conifer species varies with pit structure.

    Science.gov (United States)

    Hacke, Uwe G; Jansen, Steven

    2009-01-01

    While tracheid size of conifers is often a good proxy of water transport efficiency, correlations between conifer wood structure and transport safety remain poorly understood. It is hypothesized that at least some of the variation in bordered pit and tracheid structure is associated with both transport efficiency and embolism resistance. Stem and root samples from three boreal Pinaceae species were collected to test this hypothesis. Tracheid and pit anatomy were studied using light microscopy as well as scanning and transmission electron microscopy. While tracheid size explained at least 90% of the variation in specific conductivity for stem and root samples, the strongest correlations with embolism resistance occurred at the pit level. Both torus thickness and depth of the pit chamber showed a linear increase with greater vulnerability to cavitation. Greater embolism resistance was correlated with increasing wood density and tracheid wall reinforcement. A thinner torus may be more flexible and better able to seal the pit aperture. The pit chamber depth is proportional to the distance that the margo needs to deflect for pit aspiration.

  16. Methylbenzene-Containing Polyketides from a Streptomyces that Spontaneously Acquired Rifampicin Resistance: Structural Elucidation and Biosynthesis.

    Science.gov (United States)

    Thong, Wei Li; Shin-ya, Kazuo; Nishiyama, Makoto; Kuzuyama, Tomohisa

    2016-04-22

    Conventional screening for novel bioactive compounds in actinomycetes often results in the rediscovery of known compounds. In contrast, recent genome sequencing revealed that most of the predicted gene clusters for secondary metabolisms are not expressed under standard cultivation conditions. To explore the potential metabolites produced by these gene clusters, we implemented a cryptic gene activation strategy by screening mutants that acquire resistance to rifampicin. The induction of rifampicin resistance in 11 actinomycete strains generated 164 rifampicin-resistant mutants (rif mutants). The comparison of the metabolic profiles between the rif mutants and their wild-type strains indicated that one mutant (TW-R50-13) overproduced an unidentified metabolite (1). During the isolation and structural elucidation of metabolite 1, an additional metabolite was found; both are unprecedented compounds featuring a C5N unit and a methylbenzene moiety. Of these partial structures, the biosynthesis of the latter has not been reported. A feeding experiment using (13)C-labeled precursors demonstrated that the methylbenzene moiety is most likely synthesized by the action of polyketide synthase. The gene deletion experiments revealed that the genes for the methylbenzene moiety are located at a different locus than the genes for the C5N unit.

  17. Analysis of the series resistance and interface state densities in metal semiconductor structures

    Energy Technology Data Exchange (ETDEWEB)

    Gueler, G [Department of Physics, Faculty of Education, University of Adiyaman, 02100 Adiyaman (Turkey); Guellue, Oe [Department of Physics, Faculty of Sciences and Arts, Atatuerk University, 25240 Erzurum (Turkey); Karatas, S [Department of Physics, Faculty of Sciences and Arts, University of Kahramanmaras Suetcue Imam, 46100 Kahramanmaras (Turkey); Bakkaloglu, Oe F, E-mail: skaratas@ksu.edu.t [Department of Engineering Physics, Faculty of Engineering Physics, University of Gaziantep, 27310 Gaziantep (Turkey)

    2009-03-01

    The electrical properties of Co/n-Si metal-semiconductor (MS) Schottky structure investigated at room temperature using current-voltage (I-V) characteristics. The characteristic parameters of the structure such as barrier height, ideality factor and series resistance have been determined from the I-V measurements. The values of barrier height obtained from Norde's function were compared with those from Cheung functions, and it was seen that there was a good agreement between barrier heights from both methods. The series resistance values calculated with Cheung's two methods were compared and seen that there was an agreement with each other. However, the values of series resistance obtained from Cheung functions and Norde's functions are not agreeing with each other. Because, Cheung functions are only applied to the non-linear region (high voltage region) of the forward bias I-V characteristics. Furthermore, the energy distribution of interface state density was determined from the forward bias I-V characteristics by taking into account the bias dependence of the effective barrier height. The results show that the presence of thin interfacial layer between the metal and semiconductor.

  18. Tailorable Release of Small Molecules Utilizing Plant Viral Nanoparticles and Fibrous Matrix

    Science.gov (United States)

    Cao, Jing

    We have engineered Red clover necrotic mosaic virus (RCNMV) derived plant viral nanoparticles (PVNs) within a fibrous matrix to optimize its application for delivery and controlled release of active ingredients. RCNMV's structure and unique response to divalent cation depletion and re-addition enables the infusion of small molecules into its viral capsid through a pore formation mechanism. While this PVN technology shows a potential use in nano-scale therapeutic drug delivery, its inherent molecular dynamics to environmental stimuli places a constraint on its application and functionality as a vehicle for tailorable release of loading cargo. In this study, we enhance the understanding of the PVN technology by elucidating its mechanism for loading and triggered release of doxorubicin (Dox), a chemotherapeutic drug for breast cancer. Of critical importance is the methodology for manipulation of Dox's loading capacity and its binding location on either the exterior or interior of the virion capsid. The ability to control the active ingredient binding location provides an additional approach of tunable release from the PVN delivery vehicle besides its inherent pH- and ion- responsive release of loading cargo. The efficacious and controlled release strategy for agricultural active ingredients, such as nematicides, is also a large social need right now. Crop infestation of plant parasite nematodes causes in excess of 157 billion in worldwide crop damage annually. If an effective control strategy for these pests could be developed, it is estimated that the current market for effective nematicides is between 700 million and $1 billion each year worldwide. In this study, we report on the utilization of PVN technology to encapsulate the biological nematicide, abamectin (Abm), within the PVN's interior capsid (PVNAbm). Creating PVNAbm addresses Abm's issues of soil immobility while rendering a controlled release strategy for its bioavailability to root knot nematodes (RKNs

  19. Study of the fire resistant behavior of unfilled and carbon nanofibers reinforced polybenzimidazole coating for structural applications

    NARCIS (Netherlands)

    Iqbal, H.M.S.; Stec, A.A.; Patel, P.; Bhowmik, S.; Benedictus, R.

    2013-01-01

    With increasing interest in epoxy-based carbon fiber composites for structural applications, it is important to improve the fire resistant properties of these materials. The fire resistant performance of these materials can be improved either by using high performance epoxy resin for manufacturing

  20. Fibrous dysplasia of the frontal sinus: an uncommon cause of frontal lobe abscess.

    Science.gov (United States)

    Aygun, D; Sahin, H

    2004-11-01

    Fibrous dysplasia of the cranial air sinuses is rarely reported in the literature. This is the first report of frontal lobe abscess (FLA) associated with fibrous dysplasia of the frontal sinus (FDFS). A 29-year-old female presented with seizures and acute confusion. Cranial computed tomography (CT) revealed fibrous dysplasia of the left frontal sinus and associated FLA. She was referred to the neurosurgical service and the abscess and dysplastic tissue were removed. Histological examination confirmed fibrous dysplasia. We review the radiological appearance of FDFS with FLA. Clinicians should be aware of the association between these two conditions.

  1. Influence of deep cryogenic treatment on structure and wear resistance of materials of hydraulic breaker chisels

    Science.gov (United States)

    Bolobov, V. I.; BinhLe, Thanh

    2018-03-01

    It is shown that shallow cryogenic treatment at -75°C (SCT) of the materials of hydraulic breaker chisels - P20, 1080 and D2 steels leads to a decrease (44 ÷ 82%) in the amount of retained austenite and an increase (26 ÷ 99%) in the amount of carbides in the structure of hardened steel, which is accompanied by an increase in its hardness (1.4 ÷ 2.1%) and abrasive wear resistance (10 ÷ 31%) with a simultaneous decrease in impact toughness (19 ÷ 24%). Deep cryogenic treatment at -196°C (DCT) and subsequent low-temperature tempering of D2 steel leads to a significant increase in its wear resistance (98%) and impact toughness (32%).

  2. Seismic resistance design of nuclear power plant building structures in Japan

    International Nuclear Information System (INIS)

    Kitano, Takehito

    1997-01-01

    Japan is one of the countries where earthquakes occur most frequently in the world and has incurred a lot of disasters in the past. Therefore, the seismic resistance design of a nuclear power plant plays a very important role in Japan. This report describes the general method of seismic resistance design of a nuclear power plant giving examples of PWR and BWR type reactor buildings in Japan. Nuclear facilities are classified into three seismic classes and is designed according to the corresponding seismic class in Japan. Concerning reactor buildings, the short-term allowable stress design is applied for the S1 seismic load and it is confirmed that the structures have a safety margin against the S2 seismic load. (J.P.N.)

  3. An assessment of the resistance gene analogues of Oryza sativa ssp. japonica: their presence and structure.

    Science.gov (United States)

    Koczyk, Grzegorz; Chełkowski, Jerzy

    2003-01-01

    Rice is the first cereal genome of known draft sequence, and the finished sequence for it is now nearly complete. In this paper, we describe a preliminary analysis of known rice genes aimed to detect resistance gene analogues of known structural classes. Putative resistance genes were identified in a dual approach--by using BLASTP searches to identify candidate sequences and by using Hidden Markov Models to predict domain presence in the candidates. The set of proteins examined was obtained from the publicly available data of TIGR (The Institute for Genomic Research). 1744 distinct RGAs were identified, 597 of which belonged to the NBS-LRR class. Supplementary data (sequences and annotations) is available on the web site http:/gkoczyk.bioinfo.pl/CMBL.

  4. Seismic resistance design of nuclear power plant building structures in Japan

    Energy Technology Data Exchange (ETDEWEB)

    Kitano, Takehito [Kansai Electric Power Co., Inc., Osaka (Japan)

    1997-03-01

    Japan is one of the countries where earthquakes occur most frequently in the world and has incurred a lot of disasters in the past. Therefore, the seismic resistance design of a nuclear power plant plays a very important role in Japan. This report describes the general method of seismic resistance design of a nuclear power plant giving examples of PWR and BWR type reactor buildings in Japan. Nuclear facilities are classified into three seismic classes and is designed according to the corresponding seismic class in Japan. Concerning reactor buildings, the short-term allowable stress design is applied for the S1 seismic load and it is confirmed that the structures have a safety margin against the S2 seismic load. (J.P.N.)

  5. Finite element normal mode analysis of resistance welding jointed of dissimilar plate hat structure

    Science.gov (United States)

    Nazri, N. A.; Sani, M. S. M.

    2017-10-01

    Structural joints offer connection between structural element (beam, plate, solid etc.) in order to build a whole assembled structure. The complex behaviour of connecting elements plays a valuable role in characteristics of dynamic such as natural frequencies and mode shapes. In automotive structures, the trustworthiness arrangement of the structure extremely depends on joints. In this paper, top hat structure is modelled and designed with spot welding joint using dissimilar materials which is mild steel 1010 and stainless steel 304, using finite element software. Different types of connector elements such as rigid body element (RBE2), welding joint element (CWELD), and bar element (CBAR) are applied to represent real connection between two dissimilar plates. Normal mode analysis is simulated with different types of joining element in order to determine modal properties. Natural frequencies using RBE2, CBAR and CWELD are compared to equivalent rigid body method. Connection that gives the lowest percentage error among these three will be selected as the most reliable joining for resistance spot weld. From the analysis, it is shown that CWELD is better compared to others in term of weld joining among dissimilar plate materials. It is expected that joint modelling of finite element plays significant role in structural dynamics.

  6. Frontal sinus mucocele: a rare complication of craniofacial fibrous dysplasia.

    Science.gov (United States)

    Atasoy, C; Ustüner, E; Erden, I; Akyar, S

    2001-01-01

    We present plain radiographic, computed tomographic and magnetic resonance imaging (MRI) findings in a 25-year-old female patient with craniofacial fibrous dysplasia (FD). Although FD has a tendency to involve craniofacial bones in a unilateral fashion, the involvement was bilateral and extensive in this case. An additional feature was the presence of a frontal sinus mucocele, presumably due to the involvement of the sinus recess by the dysplastic process. This complication of the craniofacial FD has been reported very infrequently in the literature.

  7. Fibrous dysplasia of inferior turbinate, middle turbinate, and frontal sinus.

    Science.gov (United States)

    Ozcan, K M; Akdogan, O; Gedikli, Y; Ozcan, I; Dere, H; Unal, T

    2007-01-01

    Fibrous dysplasia (FD) is a non-neoplastic fibro-osseous lesion. Paranasal sinus involvement is infrequent. Involvement of the frontal sinus, sphenoid sinus, and middle turbinate is rare, and only sporadic cases have been reported in the literature. Nasal turbinates and especially the inferior turbinate are the least involved bones of the craniofacial region. To the best of our knowledge, only one case with McCune-Albright syndrome had FD of the inferior turbinate. Here, we report a rare case with FD of inferior and middle turbinates and review literature concerning FD of the craniofacial region.

  8. Endoscopic marsupialization of frontoethmoid mucocele with underlying craniofacial fibrous dysplasia.

    Science.gov (United States)

    Wie, Chan-Eun; Hong, Sung-Lyong; Mun, Sue-Jean; Cho, Kyu-Sup

    2015-01-01

    Fibrous dysplasia (FD) is a benign progressive fibro-osseous lesion that is rarely associated with mucocele formation. This complication most probably results from the involvement and subsequent occlusion of the recesses of the sinuses by the dysplastic process. The frontoethmoid mucocele associated with FD represents a rare pathology, but it is important to consider this in the differential diagnosis of patients with proptosis, visual disturbance, and bony fronto-orbital swellings. Here, we describe the first case of frontoethmoid mucocele with underlying craniofacial FD, which was successfully treated by wide marsupialization via the transnasal endoscopic approach.

  9. Fibrous dysplasia with cystic appearance in maxillary sinus.

    Science.gov (United States)

    Muraoka, H; Ishihara, A; Kumagai, J

    2001-01-01

    Fibrous dysplasia (FD) in the paranasal sinuses is uncommon, and its management may be difficult. We report the case of a 25-year-old female with FD exhibiting a cystic appearance in the maxillary sinus. The patient had been complaining of facial swelling for few years. Imagery study showed a cystic lesion and dense bone changes in the maxillary bone. Inferior meatal antrostomy with a nasal endoscope failed to confirm a histological diagnosis. After a 3-year follow-up, the degree of facial swelling was unchanged, and the patient underwent middle meatal antrostomy and was diagnosed with FD.

  10. IMPREGNATED FIBROUS CHEMOSORBENTS OF ACID GASES FOR RESPIRATORY PURPOSE

    Directory of Open Access Journals (Sweden)

    A. A. Ennan

    2017-11-01

    Full Text Available The present review is dedicated to the analysis of scientific works carried out in Physico- Chemical Institute of Environment and Human Protection (Odessa, Ukrainie and directed to the development of import-substituting sorption-filtering materials for respiratory purposes – impregnated fibrous chemisorbents (IFCS of acid gases, which are manufactured using standard equipment, as well as affordable and inexpensive chemical reagents and carriers of domestic origin. The process of chemisorption of sulphur dioxide by hexamethylenetetramine (HMTA modified nonwoven fibrous material resulted acid-catalyzed hydrolysis of HMTA to form aminomethanesulfonic acid and toxic formaldehyde. The IFCS with HMTA carried was recommended to use for air purification only from SiF4, HF, HCl and Cl2. Chemisorption of sulphur dioxide by fibrous materials impregnated by ethanolamines (monoethanolamine, diethanomamine, triethanomamine and N-methylethanolamine and polyethylenepolyamine (PEPA occurs only in the presence of “free” water with formation of “onium” sulphites, hydrosulphites and pyrosulphites. IFCS-PEPA (dynamic activity is 1,38 mmol(SO2/g are not inferior to the protective characteristics of IFCS with Na2CO3, HMTA, ethanolamines and the best foreign ionexchange fibrous chemisorbents brand VION and FIBAN (dynamic activity is 0,263 ÷0,422 mmol(SO2/g under conditions of respirators actual use (jAGM = 60 ÷ 90 %, TAGM = 297 K, VAGM = 2,0 sm/s, СSO2 = 20 ÷ 1000 mg/g3, QPEPA = 3,45 mmol/g. It is recommended to use the condensation products of primary alkylamines with formaldehyde (with large molar masses than the bases, complex compounds of amines with 3d-metals (Ni(II and Cu(II, salts of amine with aminoacids (glycine and polybasic acids (orthophosphoric acid (pKa1 = 2,12 and citric acid (pKa1 = 3,13 for manufacturing of IFCS of acid gases The IFCS with indication of dynamic absorptive capacity “wearing” (IVKS-I was developed.

  11. Solitary fibrous tumor arising in an intrathoracic goiter

    DEFF Research Database (Denmark)

    Larsen, Stine Rosenkilde; Godballe, Christian; Krogdahl, Annelise

    2010-01-01

    . CONCLUSION: The histological appearance and immunohistochemical reaction pattern of SFT is characteristic. The entity should be considered when dealing with a spindle cell lesion in the thyroid gland. All cases of this site of origin reported have had a benign clinical course. As only a small number of cases......BACKGROUND: Solitary fibrous tumor (SFT) is a rare spindle cell tumor most often found in the mediastinal pleura. Nineteen cases of SFT arising in the thyroid gland have been reported. We report a case of SFT of the thyroid gland with immunohistochemical and cytogenetic investigation. SUMMARY: A 58...

  12. A case of solitary fibrous tumor of the kidney

    Directory of Open Access Journals (Sweden)

    H N Naveen

    2011-01-01

    Full Text Available A solitary fibrous tumor (SFT is an unusual spindle cell neoplasm that usually occurs in the pleura but has recently been described in diverse extrapleural sites. Urogenital localization is rare and to our knowledge, only 39 cases of SFT of the kidney have been described. Although SFT of the kidney is extremely rare, this tumor must be included in the differential diagnosis, whenever a renal tumor consisting of mesenchymal elements is encountered. We report a case of a large SFT of the right kidney which was clinically and radiologically thought to be renal cell carcinoma and a final diagnosis of SFT was made only after immunohistochemical study.

  13. The Experiment of Drying Process of the Fibrous Material

    Directory of Open Access Journals (Sweden)

    Jiří RASZKA

    2015-06-01

    Full Text Available The article describes the experiment of water evaporation from fibrous material (cotton. The material is placed in the tube and hot air flows through (process of drying. Temperature of air is measured by thermocouple. The textile represents porous medium with certain amount of water (wet textile. Porous layer makes pressure drop when airflow starts. Properties of air (temperature, relative humidity change during evaporation process. Values of pressure drop, temperature and humidity measured during experiment are used for set up of boundary condition, porous layer and evaporation model in Ansys Fluent 13.

  14. Solitary fibrous tumor of the orbit presenting in pregnancy.

    Science.gov (United States)

    Das, Jayanta K; Sharma, Angshuman Sen; Deka, Akshay Ch; Das, Dipankar

    2009-01-01

    A 32-year-old woman, three months pregnant, reported with the complaint of protrusion of the right eye for six months. She gave history of rapid protrusion of eyeball for the last two months along with the history of double vision for the last one month. Computer tomography (CT) scan revealed a well-defined mass lesion in the intraconal space of the right orbit which was excised through a lateral orbitotomy approach. Histological examination and immunohistochemistry revealed a solitary fibrous tumor, which showed a rapid progression in pregnancy.

  15. Growth Performance and Behaviour in Grouped Pigs Fed Fibrous Diet

    OpenAIRE

    Bakare, A. G.; Madzimure, J.; Ndou, S. P.; Chimonyo, M.

    2014-01-01

    The objective of the study was to investigate the effect of feeding fibrous diets on growth performance and occurrence of aggressive behaviours in growing pigs. Sixty healthy castrated pigs (initial body weight: 46.7±4.35 kg) were used. A basal diet was diluted with maize cobs to two levels (0 and 160 g/kg dry matter). Behavioural activities were observed using video cameras for three weeks, 8 h/d starting at 0800 h. Pigs subjected to control diet gained more weight compared to pigs receiving...

  16. Metastatic melanoma mimicking solitary fibrous tumor: report of two cases.

    Science.gov (United States)

    Bekers, Elise M; van Engen-van Grunsven, Adriana C H; Groenen, Patricia J T A; Westdorp, Harm; Koornstra, Rutger H T; Bonenkamp, Johannes J; Flucke, Uta; Blokx, Willeke A M

    2014-02-01

    Malignant melanomas are known for their remarkable morphological variation and aberrant immunophenotype with loss of lineage-specific markers, especially in recurrences and metastases. Hot spot mutations in BRAF, NRAS, GNAQ, and GNA11 and mutations in KIT are oncogenic events in melanomas. Therefore, genotyping can be a useful ancillary diagnostic tool. We present one case each of recurrent and metastatic melanoma, both showing histological and immunohistochemical features of solitary fibrous tumor (SFT). Mutational analysis detected BRAF and NRAS mutations in the primary and secondary lesions, respectively. This result confirmed the diagnosis of recurrent/metastastic melanoma.

  17. Growth Performance and Behaviour in Grouped Pigs Fed Fibrous Diet

    Directory of Open Access Journals (Sweden)

    A. G. Bakare

    2014-08-01

    Full Text Available The objective of the study was to investigate the effect of feeding fibrous diets on growth performance and occurrence of aggressive behaviours in growing pigs. Sixty healthy castrated pigs (initial body weight: 46.7±4.35 kg were used. A basal diet was diluted with maize cobs to two levels (0 and 160 g/kg dry matter. Behavioural activities were observed using video cameras for three weeks, 8 h/d starting at 0800 h. Pigs subjected to control diet gained more weight compared to pigs receiving fibrous diet in week 1 (0.47 vs 0.15 kg, respectively and 2 (1.37 vs 1.04, respectively (p<0.05. Average daily gain was not affected by treatment diet in the third week. Pigs on high fibrous spent more time eating, lying down, standing, walking and fighting (p<0.05 compared to pigs on control diet. Time spent eating increased as the weeks progressed whilst time spent lying down decreased. Time of day had an effect on time spent on different behavioural activities exhibited by all pigs on different treatment diet (p<0.05. Inactivity was greatest in 5th (1200 to 1300 h hour of the day for all the pigs on different dietary treatments. Skin lesions appeared the most on neck and shoulder region followed by chest, stomach and hind leg region, and finally head region (p<0.05. Pigs on high fibre diet had more skin lesions in all body regions compared to pigs on control diet (p<0.05. It can be concluded that the high fibrous diet with maize cobs did not affect growth performance and also did not reduce aggressive behaviours. Aggressive behaviours emanated out of frustration when queuing on the feeder. The findings of this study suggest that maize cobs can be included at a level of 160 g/kg in diets of pigs. However, to reduce the level of aggression more feeding space should be provided.

  18. Angiomatoid fibrous histiocytoma in a 25-year-old male

    Directory of Open Access Journals (Sweden)

    David Dingli

    2010-06-01

    Full Text Available Angiomatoid fibrous histiocytoma (AFH is a rare disease that is often misdiagnosed initially. Patients can present with a clinical picture concerning for other diseases, and pathologic review is not always revealing. Molecular diagnostics are increasingly being utilized to detect gene fusions characteristic for AFH. Surgery remains the mainstay of management, and can effectively control local recurrences and metastases. Herein we describe a case report of a 25-year-old gentleman whose presentation was concerning for lymphoma. Subsequently we review of the relevant literature.

  19. Permeability and compression of fibrous porous media generated from dilute suspensions of fiberglass debris during a loss of coolant accident

    International Nuclear Information System (INIS)

    Lee, Saya; Abdulsattar, Suhaeb S.; Vaghetto, Rodolfo; Hassan, Yassin A.

    2015-01-01

    Highlights: • Experimental investigation on fibrous debris buildup was conducted. • Head loss through fibrous media was recorded at different approach velocities. • A head loss model through fibrous media was proposed for high porosity (>0.99). • A compression model of fibrous media was developed. - Abstract: Permeability of fibrous porous media has been studied for decades in various engineering applications, including liquid purifications, air filters, and textiles. In nuclear engineering, fiberglass has been found to be a hazard during a Loss-of-Coolant Accident. The high energy steam jet from a break impinges on surrounding fiberglass insulation materials, producing a large amount of fibrous debris. The fibrous debris is then transported through the reactor containment and reaches the sump strainers. Accumulation of such debris on the surface of the strainers produces a fibrous bed, which is a fibrous porous medium that can undermine reactor core cooling. The present study investigated the buildup of fibrous porous media on two types of perforated plate and the pressure drop through the fibrous porous media without chemical effect. The development of the fibrous bed was visually recorded in order to correlate the pressure drop, the approach velocity, and the thickness of the fibrous porous media. The experimental results were compared to semi-theoretical models and theoretical models proposed by other researchers. Additionally, a compression model was developed to predict the thickness and the local porosity of a fibrous bed as a function of pressure

  20. Structure dependent resistivity and dielectric characteristics of tantalum oxynitride thin films produced by magnetron sputtering

    Energy Technology Data Exchange (ETDEWEB)

    Cristea, D., E-mail: daniel.cristea@unitbv.ro [Department of Materials Science, Transilvania University, 500036 Brasov (Romania); Crisan, A. [Department of Materials Science, Transilvania University, 500036 Brasov (Romania); Cretu, N. [Electrical Engineering and Applied Physics Department, Transilvania University, 500036 Brasov (Romania); Borges, J. [Centro de Física, Universidade do Minho, Campus de Gualtar, 4710 - 057 Braga (Portugal); Instituto Pedro Nunes, Laboratório de Ensaios, Desgaste e Materiais, Rua Pedro Nunes, 3030-199 Coimbra (Portugal); SEG-CEMUC, Mechanical Engineering Department, University of Coimbra, 3030-788 Coimbra (Portugal); Lopes, C.; Cunha, L. [Centro de Física, Universidade do Minho, Campus de Gualtar, 4710 - 057 Braga (Portugal); Ion, V.; Dinescu, M. [National Institute for Lasers, Plasma and Radiation Physics, Lasers Department, “Photonic Processing of Advanced Materials” Group, PO Box MG-16, RO 77125 Magurele-Bucharest (Romania); Barradas, N.P. [Centro de Ciências e Tecnologias Nucleares, Instituto Superior Técnico, Universidade de Lisboa, E.N. 10 ao km 139,7, 2695-066 Bobadela LRS (Portugal); Alves, E. [Instituto de Plasmas e Fusão Nuclear, Instituto Superior Técnico, Universidade de Lisboa, E.N. 10 ao km 139,7, 2695-066 Bobadela LRS (Portugal); Apreutesei, M. [MATEIS Laboratory-INSA de Lyon, 21 Avenue Jean Capelle, 69621 Villeurbanne cedex (France); Université de Lyon, Institut des Nanotechnologies de Lyon INL-UMR5270, CNRS, Ecole Centrale de Lyon, Ecully F-69134 (France); Munteanu, D. [Department of Materials Science, Transilvania University, 500036 Brasov (Romania)

    2015-11-01

    Highlights: • Tantalum oxynitride thin films have been deposited by magnetron sputtering, in various configurations. • The rising of the reactive gases mixture flow has the consequence of a gradual increase in the non-metallic content in the films, which results in a 10 orders of magnitude resistivity domain. • The higher resistivity films exhibit dielectric constants up to 41 and quality factors up to 70. - Abstract: The main purpose of this work is to present and to interpret the change of electrical properties of Ta{sub x}N{sub y}O{sub z} thin films, produced by DC reactive magnetron sputtering. Some parameters were varied during deposition: the flow of the reactive gases mixture (N{sub 2} and O{sub 2}, with a constant concentration ratio of 17:3); the substrate voltage bias (grounded, −50 V or −100 V) and the substrate (glass, (1 0 0) Si or high speed steel). The obtained films exhibit significant differences. The variation of the deposition parameters induces variations of the composition, microstructure and morphology. These differences cause variation of the electrical resistivity essentially correlated with the composition and structural changes. The gradual decrease of the Ta concentration in the films induces amorphization and causes a raise of the resistivity. The dielectric characteristics of some of the high resistance Ta{sub x}N{sub y}O{sub z} films were obtained in the samples with a capacitor-like design (deposited onto high speed steel, with gold pads deposited on the dielectric Ta{sub x}N{sub y}O{sub z} films). Some of these films exhibited dielectric constant values higher than those reported for other tantalum based dielectric films.

  1. Structural Resistance of Reinforced Concrete Buildings in Areas of Moderate Seismicity and Assessment of Strategies for Structural Improvement

    Directory of Open Access Journals (Sweden)

    David Dominguez-Santos

    2017-10-01

    Full Text Available Moderate magnitude seismic events have occurred during the last decade in non-seismic areas and have highlighted that many existing buildings do not sufficiently resist these types of events. The objective of this work is to illustrate that most buildings dating from 2002–2010 constructed from wide beams, which were designed to previous earthquake resistance codes, do not offer a satisfactory seismic behaviour, and to identify which structural attributes can best help alleviate this problem. In this work the effect of a real earthquake of medium magnitude (Lorca, 2011 on buildings of three, five and eight stories with unidirectional frames of wide-beam concrete was assessed. The methodology included non-linear static (pushover analyses and dynamic response simulations with the aim to understand the effect on the seismic performance of changing some of the geometrical and material parameters. Maximum displacements and capacity curves for the top floor of a set of representative buildings were evaluated and compared. In particular, capacity curves obtained from non-linear static (pushover analysis are compared for different building configurations, as well as the maximum displacements obtained through non-linear dynamic analysis. This paper highlights the seismic vulnerability of buildings constructed between 2002 and 2010 and the results indicate that a higher density of infill walls (walls whose bricks are not part of the main structure is the feature that most significantly improves the seismic behaviour of the structures analysed. Moreover, counterintuitively, incorporating stronger concrete and reinforcing steel and using alternative column arrangements only have a small positive effect on the seismic behaviour of these types of buildings.

  2. INVESTIGATION OF PLASMA WEAR RESISTANCE COATING STRUCTURE ON BASIS OF OXIDE CERAMICS WITH INCLUSIONS OF SOLID LUBRICATION

    Directory of Open Access Journals (Sweden)

    F. I. Panteleenko

    2013-01-01

    Full Text Available The paper describes an investigation of the structure, chemical and phase composition of wear resistance coatings on the basis of  oxide ceramics with inclusions of  solid lubrication.

  3. Near-Net-Shape Processing of Sintered Fibrous Ceramics Achieved

    Science.gov (United States)

    Angel, Paul W.

    2000-01-01

    A variety of sintered fibrous ceramic (SFC) materials have been developed over the last 50 years as thermal barrier materials for reentry applications. SFC materials typically exhibit very low thermal conductivities combined with low densities and good thermal stability up to 2500 F. These materials have flown successfully on the space shuttle orbiters since the 1960's. More recently, the McDonnell Douglas Corporation successfully used SFC tiles as a heat shield on the underside of its DC X test vehicle. For both of these applications, tiles are machined from blocks of a specific type of SFC called an alumina-enhanced thermal barrier (AETB). The sizes of these blocks have been limited by the manufacturing process. In addition, as much as 80 to 90 percent of the material can be lost during the machining of tiles with significant amounts of curvature. To address these problems, the NASA Glenn Research Center at Lewis Field entered a cooperative contract with the Boeing Company to develop a vacuum-assisted forming process that can produce large (approximately 4 square feet), severely contoured panels of AETB while saving costs in comparison to the conventional cast-and-machine billet process. For shuttle use, AETB is slurry cast, drained, and fired to form square billets conforming to the shape of the filtration box. The billets are then cut into tiles of the appropriate size for thermally protecting the space shuttle. Processing techniques have limited the maximum size of AETB billets to 21.5 square inches by 6.5-in. thick, but the space shuttles use discrete heat shield tiles no more than 8 to 12 square inches. However, in other applications, large, complex shapes are needed, and the tiling approach is undesirable. For such applications, vacuum-assisted forming can produce large parts with complex shapes while reducing machining waste and eliminating cemented joints between bonded billets. Because it allows contoured shapes to be formed, material utilization is

  4. Population structure of Japanese extraintestinal pathogenic Escherichia coli and its relationship with antimicrobial resistance.

    Science.gov (United States)

    Matsumura, Yasufumi; Noguchi, Taro; Tanaka, Michio; Kanahashi, Toru; Yamamoto, Masaki; Nagao, Miki; Takakura, Shunji; Ichiyama, Satoshi

    2017-04-01

    To define the population structure of extraintestinal pathogenic Escherichia coli (ExPEC) in Japan and its relationship with antimicrobial resistance and the major resistance mechanisms for fluoroquinolones and β-lactams, we designed a multicentre prospective study. A total of 329 ExPEC isolates were collected at 10 Japanese acute-care hospitals during December 2014. We defined the clonal groups of ExPEC by fumC and fimH sequencing (CH typing). Antimicrobial susceptibility testing of 18 agents and the detection of mutations in quinolone resistance-determining regions (QRDRs) and β-lactamases were performed. Among the study isolates, 103 CH types were found, and CH40-30 (25%) and another 10 CH types (35% in total) constituted the major ExPEC population. Ciprofloxacin non-susceptibility, ESBLs and MDR phenotypes were found in 34%, 22% and 33%, respectively. CH40-30, corresponding to the C/H30 clade of the global pandemic ST131 clone, was associated with four QRDR mutations (100%) and bla CTX-M (60%) and was the most frequent type in 15 antimicrobial-non-susceptible populations (dominating 39%-75% of each population, the highest prevalence for ciprofloxacin), the ESBL producers (70%) and the MDR isolates (59%). Isolates that were non-susceptible to nalidixic acid and low-level resistant to ciprofloxacin with one or two QRDR mutations represented 16% of the study isolates and were distributed among the eight major and non-major CH types. More than half of the ExPEC population in Japan consisted of 11 major clones. Of these clones, the CH40-30-ST131-C/H30 clone was the predominant antimicrobial-resistant population. The presence of major clones with low-level ciprofloxacin resistance supports the potential future success of a non-ST131 fluoroquinolone-resistant clone. © The Author 2017. Published by Oxford University Press on behalf of the British Society for Antimicrobial Chemotherapy. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  5. Optimization of chemical structure of Schottky-type selection diode for crossbar resistive memory.

    Science.gov (United States)

    Kim, Gun Hwan; Lee, Jong Ho; Jeon, Woojin; Song, Seul Ji; Seok, Jun Yeong; Yoon, Jung Ho; Yoon, Kyung Jean; Park, Tae Joo; Hwang, Cheol Seong

    2012-10-24

    The electrical performances of Pt/TiO(2)/Ti/Pt stacked Schottky-type diode (SD) was systematically examined, and this performance is dependent on the chemical structures of the each layer and their interfaces. The Ti layers containing a tolerable amount of oxygen showed metallic electrical conduction characteristics, which was confirmed by sheet resistance measurement with elevating the temperature, transmission line measurement (TLM), and Auger electron spectroscopy (AES) analysis. However, the chemical structure of SD stack and resulting electrical properties were crucially affected by the dissolved oxygen concentration in the Ti layers. The lower oxidation potential of the Ti layer with initially higher oxygen concentration suppressed the oxygen deficiency of the overlying TiO(2) layer induced by consumption of the oxygen from TiO(2) layer. This structure results in the lower reverse current of SDs without significant degradation of forward-state current. Conductive atomic force microscopy (CAFM) analysis showed the current conduction through the local conduction paths in the presented SDs, which guarantees a sufficient forward-current density as a selection device for highly integrated crossbar array resistive memory.

  6. Multi-scale modeling of soft fibrous tissues based on proteoglycan mechanics.

    Science.gov (United States)

    Linka, Kevin; Khiêm, Vu Ngoc; Itskov, Mikhail

    2016-08-16

    Collagen in the form of fibers or fibrils is an essential source of strength and structural integrity in most organs of the human body. Recently, with the help of complex experimental setups, a paradigm change concerning the mechanical contribution of proteoglycans (PGs) took place. Accordingly, PG connections protect the surrounding collagen fibrils from over-stretching rather than transmitting load between them. In this paper, we describe the reported PG mechanics and incorporate it into a multi-scale model of soft fibrous tissues. To this end, a nano-to-micro model of a single collagen fiber is developed by taking the entropic-energetic transition on the collagen molecule level into account. The microscopic damage occurring inside the collagen fiber is elucidated by sliding of PGs as well as by over-stretched collagen molecules. Predictions of this two-constituent-damage model are compared to experimental data available in the literature. Copyright © 2016 Elsevier Ltd. All rights reserved.

  7. Flexural Behaviour of Precast Aerated Concrete Panel (PACP with Added Fibrous Material: An Overview

    Directory of Open Access Journals (Sweden)

    Abdul Rahim Noor Hazlin

    2017-01-01

    Full Text Available The usage of precast aerated concrete panel as an IBS system has become the main alternative to conventional construction system. The usage of this panel system contributes to a sustainable and environmental friendly construction. This paper presents an overview of the precast aerated concrete panel with added fibrous material (PACP. PACP is fabricated from aerated foamed concrete with added Polypropylene fibers (PP. The influence of PP on the mechanical properties of PACP are studied and reviewed from previous research. The structural behaviour of precast concrete panel subjected to flexure load is also reviewed. It is found that PP has significant affects on the concrete mixture’s compressive stregth, tensile strength and flexural strength. It is also found that PP manage to control the crack propagation in the concrete panel.

  8. Solitary fibrous tumour of the lower leg: an uncommon site with atypical histopathological features

    Science.gov (United States)

    Sherwani, Rana K; Kumar, Amit

    2010-01-01

    A 40-year-old man of low socioeconomic status presented with a slowly growing painless mass for 1 year at the antero-medial aspect of the right leg. On local examination, the overlying skin was normal and the mass was soft to firm in consistency, non-tender and freely mobile with no fixity to underlying structures. MRI revealed a lobulated mass with central areas of necrosis and no involvement of underlying muscles and neurovascular bundles suggesting a benign soft tissue tumour. The tumour was totally excised and submitted for histopathological examination, which, along with immunopositivity for CD34, CD99 and focally for Bcl2, led to a confirmatory diagnosis of solitary fibrous tumour with atypical histopathological features of increased mitosis and necrosis. After 4 months of follow-up, the patient was disease free without any recurrence or metastasis. PMID:22791854

  9. The impacts of triclosan on anaerobic community structures, function, and antimicrobial resistance.

    Science.gov (United States)

    McNamara, Patrick J; LaPara, Timothy M; Novak, Paige J

    2014-07-01

    Triclosan is a widespread antimicrobial agent that accumulates in anaerobic digesters used to treat the residual solids generated at municipal wastewater treatment plants; there is very little information, however, about how triclosan impacts microbial communities in anaerobic digesters. We investigated how triclosan impacts the community structure, function and antimicrobial resistance genes in lab-scale anaerobic digesters. Previously exposed (to triclosan) communities were amended with 5, 50, and 500 mg/kg of triclosan, corresponding to the median, 95th percentile, and 4-fold higher than maximum triclosan concentration that has been detected in U.S. biosolids. Triclosan amendment caused all of the Bacteria and Archaea communities to structurally diverge from that of the control cultures (based on ARISA). At the end of the experiment, all triclosan-amended Archaea communities had diverged from the control communities, regardless of the triclosan concentration added. In contrast, over time the Bacteria communities that were amended with lower concentrations of triclosan (5 mg/kg and 50 mg/kg) initially diverged and then reconverged with the control community structure. Methane production at 500 mg/kg was nearly half the methane production in control cultures. At 50 mg/kg, a large variability in methane production was observed, suggesting that 50 mg/kg may be a tipping point where function begins to fail in some communities. When previously unexposed communities were exposed to 500 mg triclosan/kg, function was maintained, but the abundance of a gene encoding for triclosan resistance (mexB) increased. This research suggests that triclosan could inhibit methane production in anaerobic digesters if concentrations were to increase and may also select for resistant Bacteria. In both cases, microbial community composition and exposure history alter the influence of triclosan.

  10. Malignant fibrous histiocytoma of the face: report of a case

    Directory of Open Access Journals (Sweden)

    Bánkfalvi Ágnes

    2007-10-01

    Full Text Available Abstract Background Soft tissue sarcomas in the head and neck region are rare and often present a difficult differential diagnosis. The aim of our presentation is to point out the complexity of the diagnosis, treatment and follow up. Case presentation An eighty-seven year old female patient was referred to our unit with a fast growing brownish lump on the face. Four months beforehand, a benign fibrous histiocytoma (BFH had been removed from the same location by excision biopsy with wide tumour-free resection margins. Excision biopsy of the recurrent lesion revealed a malignant fibrous histiocytoma (MFH. Radical tumour resection was completed by extended parotidectomy and neck dissection; the skin defect was covered by a regional bi-lobed flap. No adjuvant radio- or chemotherapy was administered. Full functional and cosmetic recovery was achieved; follow-up has been uneventful more than two years postoperatively. Discussion Malignant transformation of BFH is extremely rare and if so, extended radical surgery may give a fair chance for a favourable outcome even in patients with advanced age.

  11. Fibrous Fillers to Manufacture Ultra High Ash/Performance Paper

    Energy Technology Data Exchange (ETDEWEB)

    Dr. VIjay K. Mathur

    2009-04-30

    The paper industry is one of the largest users of energy and emitters of CO2 in the US manufacturing industry. In addition to that, it is facing tremendous financial pressure due to lower cost imports. The fine paper industry has shrunk from 15 million tons per year production to 10 million tons per year in the last 5 years. This has resulted in mill closures and job loses. The AF&PA and the DOE formed a program called Agenda 2020 to help in funding to develop breakthrough technologies to provide help in meeting these challenges. The objectives of this project were to optimize and scale-up Fibrous Fillers technology, ready for commercial deployment and to develop ultra high ash/high performance paper using Fibrous Fillers. The goal was to reduce energy consumption, carbon footprint, and cost of manufacturing paper and related industries. GRI International (GRI) has been able to demonstrate the techno - economic feasibility and economic advantages of using its various products in both handsheets as well as in commercial paper mills. GRI has also been able to develop sophisticated models that demonstrate the effect of combinations of GRI's fillers at multiple filler levels. GRI has also been able to develop, optimize, and successfully scale-up new products for use in commercial paper mills.

  12. Heat Transfer Modeling for Rigid High-Temperature Fibrous Insulation

    Science.gov (United States)

    Daryabeigi, Kamran; Cunnington, George R.; Knutson, Jeffrey R.

    2012-01-01

    Combined radiation and conduction heat transfer through a high-temperature, high-porosity, rigid multiple-fiber fibrous insulation was modeled using a thermal model previously used to model heat transfer in flexible single-fiber fibrous insulation. The rigid insulation studied was alumina enhanced thermal barrier (AETB) at densities between 130 and 260 kilograms per cubic meter. The model consists of using the diffusion approximation for radiation heat transfer, a semi-empirical solid conduction model, and a standard gas conduction model. The relevant parameters needed for the heat transfer model were estimated from steady-state thermal measurements in nitrogen gas at various temperatures and environmental pressures. The heat transfer modeling methodology was evaluated by comparison with standard thermal conductivity measurements, and steady-state thermal measurements in helium and carbon dioxide gases. The heat transfer model is applicable over the temperature range of 300 to 1360 K, pressure range of 0.133 to 101.3 x 10(exp 3) Pa, and over the insulation density range of 130 to 260 kilograms per cubic meter in various gaseous environments.

  13. Modeling fibrous biological tissues with a general invariant that excludes compressed fibers

    Science.gov (United States)

    Li, Kewei; Ogden, Ray W.; Holzapfel, Gerhard A.

    2018-01-01

    Dispersed collagen fibers in fibrous soft biological tissues have a significant effect on the overall mechanical behavior of the tissues. Constitutive modeling of the detailed structure obtained by using advanced imaging modalities has been investigated extensively in the last decade. In particular, our group has previously proposed a fiber dispersion model based on a generalized structure tensor. However, the fiber tension-compression switch described in that study is unable to exclude compressed fibers within a dispersion and the model requires modification so as to avoid some unphysical effects. In a recent paper we have proposed a method which avoids such problems, but in this present study we introduce an alternative approach by using a new general invariant that only depends on the fibers under tension so that compressed fibers within a dispersion do not contribute to the strain-energy function. We then provide expressions for the associated Cauchy stress and elasticity tensors in a decoupled form. We have also implemented the proposed model in a finite element analysis program and illustrated the implementation with three representative examples: simple tension and compression, simple shear, and unconfined compression on articular cartilage. We have obtained very good agreement with the analytical solutions that are available for the first two examples. The third example shows the efficacy of the fibrous tissue model in a larger scale simulation. For comparison we also provide results for the three examples with the compressed fibers included, and the results are completely different. If the distribution of collagen fibers is such that it is appropriate to exclude compressed fibers then such a model should be adopted.

  14. Electrospinning of multicomponent ultrathin fibrous nonwovens for semi-occlusive wound dressings.

    Science.gov (United States)

    Hong, Youliang; Li, Yanan; Zhuang, Xiuli; Chen, Xuesi; Jing, Xiabin

    2009-05-01

    This work describes the design and assembly of multifunctional and cost-efficient composite fiber nonwovens as semi-occlusive wound dressings using a simple electrospinning process to incorporate a variety of functional components into an ultrathin fiber. These components include non-hydrophilic poly(L-lactide) (PLLA) as fibrous backbone, hydrophilic poly(vinyl pyrrolidone)-iodine (PVP-I), TiO(2) nanoparticles, zinc chloride as antimicrobial, odor-controlling, and antiphlogistic agents, respectively. The process of synthesis starts with a multicomponent solution of PLLA, PVP, TiO(2) nanoparticles plus zinc chloride, in which TiO(2) nanoparticles are synthesized by in situ hydrolysis of TiO(2) precursors in a PVP solution for the sake of obtaining the particle-uniformly dispersive solution. Subsequent electrospinning generates the corresponding composite fibers. A further iodine vapor treatment to the composite fibers combines iodine with PVP to produce the PVP-I complexes. Experiments indicate that the assembled composite fibers (300-400 nm) possess the ointment-releasing characteristic and the phase-separate, core-sheath structures in which PVP-I residing in fiber surface layer becomes the sheath, and PLLA distributing inside the fiber acts as the core. Based on this design, the structural advantages combining active components endow the assembled composite nonwovens with a variety of functions, especially, the existence of PVP-I, endows the nonwoven with water absorbability, antimicrobial activity, adhesive ability, and transformable characteristic from hydrophilicity to non-hydrophilicity. The multifunctional, cost-efficient, and ointment-releasing characteristics make the multicomponent composite fibrous nonwovens potentially useful in applications such as initial stage of dressing of the cankerous or contaminated wounds.

  15. Crystal Structures of Wild-type and Mutant Methicillin-resistant Staphylococcus aureus Dihydrofolate Reductase Reveal an Alternative Conformation of NADPH that may be Linked to Trimethoprim Resistance

    Energy Technology Data Exchange (ETDEWEB)

    Frey, K.; Liu, J; Lombardo, M; Bolstad, D; Wright, D; Anderson, A

    2009-01-01

    Both hospital- and community-acquired Staphylococcus aureus infections have become major health concerns in terms of morbidity, suffering and cost. Trimethoprim-sulfamethoxazole (TMP-SMZ) is an alternative treatment for methicillin-resistant S. aureus (MRSA) infections. However, TMP-resistant strains have arisen with point mutations in dihydrofolate reductase (DHFR), the target for TMP. A single point mutation, F98Y, has been shown biochemically to confer the majority of this resistance to TMP. Using a structure-based approach, we have designed a series of novel propargyl-linked DHFR inhibitors that are active against several trimethoprim-resistant enzymes. We screened this series against wild-type and mutant (F98Y) S. aureus DHFR and found that several are active against both enzymes and specifically that the meta-biphenyl class of these inhibitors is the most potent. In order to understand the structural basis of this potency, we determined eight high-resolution crystal structures: four each of the wild-type and mutant DHFR enzymes bound to various propargyl-linked DHFR inhibitors. In addition to explaining the structure-activity relationships, several of the structures reveal a novel conformation for the cofactor, NADPH. In this new conformation that is predominantly associated with the mutant enzyme, the nicotinamide ring is displaced from its conserved location and three water molecules complete a network of hydrogen bonds between the nicotinamide ring and the protein. In this new position, NADPH has reduced interactions with the inhibitor. An equilibrium between the two conformations of NADPH, implied by their occupancies in the eight crystal structures, is influenced both by the ligand and the F98Y mutation. The mutation induced equilibrium between two NADPH-binding conformations may contribute to decrease TMP binding and thus may be responsible for TMP resistance.

  16. A Built-In Self-Test Structure (BIST) for Resistive RAMs characterization: Application to bipolar OxRRAM

    Science.gov (United States)

    Aziza, H.; Bocquet, M.; Moreau, M.; Portal, J.-M.

    2015-01-01

    Resistive Random Access Memory (RRAM) is a form of nonvolatile storage that operates by changing the resistance of a specially formulated solid dielectric material [1]. Among RRAMs, oxide-based Resistive RAMs (so-called OxRRAMs) are promising candidates due their compatibility with CMOS processes and high ON/OFF resistance ratio. Common problems with OxRRAM are related to high variability in operating conditions and low yield. OxRRAM variability mainly impact ON/OFF resistance ratio. This ratio is a key parameter to determine the overall performance of an OxRRAM memory. In this context, the presented built-in structure allows collecting statistical data related to the OxRRAM memory array (ON/OFF resistance distributions) for reliability assessment of the technology.

  17. Structure and corrosion resistance of Co-Cr-Mo alloy used in Birmingham Hip Resurfacing system.

    Science.gov (United States)

    Dobruchowska, Ewa; Paziewska, Monika; Przybyl, Krzysztof; Reszka, Kazimierz

    2017-01-01

    The endoprostheses made of cobalt-chromium-molybdenum (Co-Cr-Mo) alloys belong to the group of the most popular metallic implants used for reconstruction of hip joints. For such biomaterials, the primary goal is a correct and long-term functioning in the aggressive environment of body fluids. Therefore, the purpose of this study was to examine both the morphology and the corrosion resistance of implants made of the cobalt alloy used in Birmingham Hip Resurfacing (BHR) system (Smith & Nephew). For comparative purposes, the electrochemical studies were done for the nitrided stainless steel - Orthinox. Observations of the microstructure of the material under investigation were performed by means of the optical metallographic microscope and the scanning electron microscope. Furthermore, Energy Dispersive X-ray Spectroscopy was used to analyse the chemical composition of the endoprosthesis. Characterisation and evaluation of electrochemical corrosion resistance of the selected alloys were performed by potentiodynamic polarisation tests. The structural studies confirmed that Co-Cr-Mo (BHR system) is characterised by a typical dendritic microstructure with carbide precipitates, mainly M23C6, within the interdendritic areas. The results of the polarisation measurements showed that the cobalt alloy investigated exhibits lower corrosion potential than Orthinox in the utilised environments (3% NaCl, simulated body fluid - Hank's Body Fluid). However, the high passivation ability of the Co-Cr-Mo alloy, as well as its resistance to the initiation and propagation of localised corrosion processes, indicate that this material is significantly more appropriate for long-term implants.

  18. Resistive switching characteristics of Pt/TaOx/HfNx structure and its performance improvement

    Directory of Open Access Journals (Sweden)

    Qigang Zhou

    2013-03-01

    Full Text Available The refractory transition metal nitride (TMN film Hafnium nitride (HfNx was successfully prepared on silicon-based substrates as bottom electrodes for resistive random access memory (RRAM cells in Pt (top/metal oxide/ HfNx (bottom sandwich structure. The reproducible resistive switching (RS characteristics of the memory cells were studied systematically for RRAM applications. The advantages of adopting HfNx instead of Pt as bottom electrode material were demonstrated, including the improvement of the low resistive state value, the RS endurance and the uniformity of RS parameters. The composition and chemical bonding states of the prepared HfNx was analyzed by X-ray photoelectron spectroscopy (XPS technique. The nitrogen content in the HfNx and the Gibbs free energy of the corresponding metal oxide formation has great influences on the RS properties. The oxygen reservoir ability and diffusion barrier effect of the HfNx play a key role in the RS performance improvement of the RRAM devices.

  19. Tuning the resistive switching memory in a metal–ferroelectric–semiconductor capacitor by field effect structure

    Energy Technology Data Exchange (ETDEWEB)

    Wang, S.Y., E-mail: shouyu.wang@yahoo.com [College of Physics and Electronic Information Science, Tianjin Normal University, Tianjin 300074 (China); Guo, F.; Wang, X. [College of Physics and Electronic Information Science, Tianjin Normal University, Tianjin 300074 (China); Liu, W.F., E-mail: wfliu@tju.edu.cn [Department of Applied Physics, Faculty of Science, Tianjin University, Weijin Road, Nankai District, Tianjin 300072 (China); Gao, J., E-mail: jugao@hku.hk [Department of Physics, the University of Hong Kong, Pokfulam Road (Hong Kong)

    2015-11-30

    Highlights: • Bistable or tristable electrically conducting state is observed. • Coefficient can be tuned in situ by modulating carrier's density. • The RS effects may be of significance for multi-source controlled memory devices. - Abstract: Resistive switching (RS) effects based on a correlation between ferroelectric polarization and conductivity might become of particular interest for nonvolatile memory applications, because they are not subjected to the scaling restrictions. Here we report on RS behaviors modulated by a reversal of ferroelectric polarization in heterostructures comprising of a ferroelectric layer and a semiconducting manganite film. It is found that electrically conducting state is bistable or even tristable; and via the polarization flipping, a maximum resistive switching coefficient (R{sub max}/R{sub min}) is found to be larger than 3000 with bias of 6 V in Ag/BaTiO{sub 3}/La{sub 0.8}Ca{sub 0.2}MnO{sub 3} at room temperature. More importantly, employing field-effect structure with ferroelectric PMN-PT as substrate, we found that the resistive switching behaviors can be tuned in situ by modulating the concentration of carriers in the semiconducting manganite layer. Possible mechanisms are discussed on the basis of the interplay of bound ferroelectric charges, charged defects in ferroelectric layer and mobile carriers in manganite thin films. The giant RS effects observed here may be of significance for memory devices by combing electronic conduction with magnetic, spintronic, and optical functionalities.

  20. Crosslinked copolyazoles with a zwitterionic structure for organic solvent resistant membranes

    KAUST Repository

    Chisca, Stefan

    2015-01-01

    The preparation of crosslinked membranes with a zwitterionic structure based on a facile reaction between a newly synthesized copolyazole with free OH groups and (3-glycidyloxypropyl)trimethoxysilane (GPTMS) is reported. The new OH-functionalized copolyazole is soluble in common organic solvents, such as tetrahydrofuran (THF), dimethylsulfoxide (DMSO), N,N′-dimethylformamide (DMF) and N-methyl-2-pyrrolidone (NMP) and can be easily processed by phase inversion. After crosslinking with GPTMS, the membranes acquire high solvent resistance. We show the membrane performance and the influence of the crosslinking reaction conditions on the thermal stability, surface polarity, pore morphology, and solvent resistance. By using UV-spectroscopy we monitored the solvent resistance of the membranes in four aggressive solvents (THF, DMSO, DMF and NMP) for 30 days. After this time, only minor changes (less than 2%) were detected for membranes subjected to a crosslinking reaction for 6 hours or longer. Our data suggest that the novel crosslinked membranes can be used for industrial applications in wide harsh environments in the presence of organic solvents.

  1. Improved resistive switching reliability by using dual-layer nanoporous carbon structure

    Science.gov (United States)

    Tao, Ye; Li, Xuhong; Wang, Zhongqiang; Xu, Haiyang; Ding, Wentao; Ma, Jiangang; Liu, Yichun

    2017-10-01

    We optimized the diameter and microgeometry of preformed conductive filaments (CFs) to improve the switching reliability of copper/nanoporous amorphous carbon (a-C)/platinum memory devices. Forming-free devices were obtained because of the introduction of preformed CFs into the nanoporous layer during the copper electrode evaporation process. The switching fluctuation decreased with the increasing preformed CF size in a certain range; however, the device with stronger preformed CFs suffered from high current in the first RESET process. Furthermore, to achieve both high switching uniformity and low power consumption, a dual-layer structure was proposed to regulate the microgeometry of preformed CFs. Compared with those of a pristine device and single-layer nanoporous device, the fluctuation of high/low resistance values was further suppressed to 26% and 21%, respectively. In addition, Resistive random access memory (RRAM) devices exhibited a fast switching speed (endurance (>105 cycles), and long retention time (>105 s at 85 °C). These results reveal the key role of preformed CF optimization in resistive switching performance improvement, providing an effective approach to develop high-performance RRAM devices.

  2. Ductile crack growth resistance of PWR components. Application for structural integrity assessment

    International Nuclear Information System (INIS)

    Bethmont, M.; Eripret, C.; Le Delliou, P.; Frund, J.M.

    1995-01-01

    Structural integrity assessment of PWR components, as pressure vessel and piping, needs to evaluate the ductile crack growth resistance which is generally characterized by J resistance curves (or J-R curves) based on the path-independent J Integral. These curves are more often obtained from laboratory tests with small specimens as CT-specimens and their application to large component safety analysis could be questionable Indeed, it is well known that J-R curves could depend on the specimen size and on the loading mode (i.e. bending stress versus tensile stress) but this dependency could be different from one material to another. This means that it would depend not only on the stress-strain state but also on the actual local fracture mechanisms (i. e. the damage) occurring before the crack initiation or during the crack propagation. The purpose of this paper is to gather some results of crack growth resistance measurement studied at EDF with different materials in order to show how the effect of the parameters, as specimen geometry and mode of loading, is directly related to the local fracture mechanisms or the microstructure of the materials. For that a number of results are analysed by means of the local approach of fracture which is a very useful tool to predict quantitatively the J-R curve dependency, related to fracture mechanisms (authors). 12 refs., 9 figs

  3. Structural sensitivity of cyclic crack resistance of rotor steel in gaseous hydrogen

    International Nuclear Information System (INIS)

    Romaniv, O.N.; Nikiforchin, G.N.; Kozak, L.Yu.

    1984-01-01

    Comparative evaluation of cyclic crack resistance of hardened rotor set steel 35KhN3MFA in different cstructural states during tesis in agea geseous hydrogen, in the air and in vacuum, has been mde made. It is shown, that structural sensitivity of near-threshold crack resistance of the studied rotor steel in gaseous hydrogen is to a high extent determined by the closing and morphology of fatigue crack. The decrease in crack closing (CC) observed during tests in hydrogen in low-strenght and crack branching in high-strength steels results in the fact, that in contrast to well-known notions on a higher sensitivity to hydrogen embrittlement of high-strenght alloys the negative effect of hydrogen on the near-threshold cyclic crack resistance is manifested only in steel in low-strenght state. The considered regularities in crack growth in low-alloyed steel under the effect of gaseous hydrogen are just only for high-frequency loading. In all probability in the case of fatigue crack growth (GCG) at low frequencies of loading not only the medium activity, but also the role o, closing and crack geometty in the kinetics of fatigue fracture, the clarifying of which requires further studieds, will change

  4. Resistance to malaria through structural variation of red blood cell invasion receptors.

    Science.gov (United States)

    Leffler, Ellen M; Band, Gavin; Busby, George B J; Kivinen, Katja; Le, Quang Si; Clarke, Geraldine M; Bojang, Kalifa A; Conway, David J; Jallow, Muminatou; Sisay-Joof, Fatoumatta; Bougouma, Edith C; Mangano, Valentina D; Modiano, David; Sirima, Sodiomon B; Achidi, Eric; Apinjoh, Tobias O; Marsh, Kevin; Ndila, Carolyne M; Peshu, Norbert; Williams, Thomas N; Drakeley, Chris; Manjurano, Alphaxard; Reyburn, Hugh; Riley, Eleanor; Kachala, David; Molyneux, Malcolm; Nyirongo, Vysaul; Taylor, Terrie; Thornton, Nicole; Tilley, Louise; Grimsley, Shane; Drury, Eleanor; Stalker, Jim; Cornelius, Victoria; Hubbart, Christina; Jeffreys, Anna E; Rowlands, Kate; Rockett, Kirk A; Spencer, Chris C A; Kwiatkowski, Dominic P

    2017-06-16

    The malaria parasite Plasmodium falciparum invades human red blood cells by a series of interactions between host and parasite surface proteins. By analyzing genome sequence data from human populations, including 1269 individuals from sub-Saharan Africa, we identify a diverse array of large copy-number variants affecting the host invasion receptor genes GYPA and GYPB We find that a nearby association with severe malaria is explained by a complex structural rearrangement involving the loss of GYPB and gain of two GYPB-A hybrid genes, which encode a serologically distinct blood group antigen known as Dantu. This variant reduces the risk of severe malaria by 40% and has recently increased in frequency in parts of Kenya, yet it appears to be absent from west Africa. These findings link structural variation of red blood cell invasion receptors with natural resistance to severe malaria. Copyright © 2017, American Association for the Advancement of Science.

  5. Wear Resistance of Steels with Surface Nanocrystalline Structure Generated by Mechanical-Pulse Treatment.

    Science.gov (United States)

    Nykyforchyn, Hryhoriy; Kyryliv, Volodymyr; Maksymiv, Olha

    2017-12-01

    The influence of the surface mechanical-pulse treatment based on high-speed friction with a rapid cooling by the technological environment on the wear resistance of medium- and high-carbon steels was considered. The treatment due to a severe plastic deformation enabled obtaining the nanocrystalline structure with a grain size of 14-40 nm. A high positive effect of this treatment was obtained not only because of metal nanocrystallization but also thanks to other factors, namely, structural-phase transformations, carbon saturation of the surface due to decomposition of the coolant and the friction coefficient decrease. Higher carbon content leads to better strengthening of the surface, and its microhardness can reach 12 GPa.

  6. Improving of wear resistance of alloys with metastable austenite structure in abrasion wearing

    International Nuclear Information System (INIS)

    Popov, V.S.; Brykov, N.N.; Pugachev, G.A.

    1979-01-01

    The effect of grain composition of abrasive masses upon the wear resistance of alloys having a metastable austenitic structure is studied. The investigations have been carried out on Kh12F1 steel, using diffraction and hardness measurements and the metallographic analysis. Experimental data indicate that the specific wear of the stable alloys increases substantially with the size of abrasive particles. As regards the metastable alloys, the increase in the size of the abrasive grains has little effect upon the specific wear, as the increasing abradability of the grains is compensated for by the strengthening of the rubbing surfaces, this resulting from the ability of the metal surface layer to underao structure transformations in the course of wear

  7. Crystal Structure of the Protease-Resistant Core Domain of Yersinia Pestis Virulence Factor Yopr

    Energy Technology Data Exchange (ETDEWEB)

    Schubot,F.; Cherry, S.; Austin, B.; Tropea, J.; Waugh, D.

    2005-01-01

    Yersinia pestis, the causative agent of the plague, employs a type III secretion system (T3SS) to secrete and translocate virulence factors into the cytoplasm of mammalian host cells. One of the secreted virulence factors is YopR. Little is known about the function of YopR other than that it is secreted into the extracellular milieu during the early stages of infection and that it contributes to virulence. Hoping to gain some insight into the function of YopR, we determined the crystal structure of its protease-resistant core domain, which consists of residues 38--149 out of 165 amino acids. The core domain is composed of five {alpha}-helices that display unexpected structural similarity with one domain of YopN, a central regulator of type III secretion in Y. pestis. This finding raises the possibility that YopR may play a role in the regulation of type III secretion.

  8. BJT-based detector on high-resistivity silicon with integrated biasing structure

    Science.gov (United States)

    Verzellesi, G.; Batignani, G.; Bettarini, S.; Boscardin, M.; Bosisio, L.; Dalla Betta, G.-F.; Giacomini, G.; Piemonte, C.

    2006-11-01

    A novel method for biasing phototransistor-based radiation detectors on high-resistivity Si is presented, that relies on the integration into the detector base of a pnp transistor acting as a current source. The proposed approach can be extended in a natural way to the biasing of npn detector arrays, allowing different detectors to be biased at the same quiescent current, by connecting all the biasing pnp transistors with a diode-connected reference transistor (integrated onto the same chip), so that they form a current-mirror circuit. Relying on two-dimensional numerical device simulations, several test structures have been designed and fabricated, including single BJT detectors and detector arrays with pnp biasing transistors connected in the current-mirror configuration. The electrical characterization of fabricated structures shows that both single detectors and detector arrays are operational and behave in good agreement with simulations, thus demonstrating the feasibility of the proposed approach.

  9. Structural and Functional Basis for Targeting Campylobacter jejuni Agmatine Deiminase To Overcome Antibiotic Resistance.

    Science.gov (United States)

    Shek, Roger; Dattmore, Devon A; Stives, Devin P; Jackson, Ashley L; Chatfield, Christa H; Hicks, Katherine A; French, Jarrod B

    2017-12-26

    Campylobacter jejuni is the most common bacterial cause of gastroenteritis and a major contributor to infant mortality in the developing world. The increasing incidence of antibiotic-resistant C. jejuni only adds to the urgency to develop effective therapies. Because of the essential role that polyamines play, particularly in protection from oxidative stress, enzymes involved in the biosynthesis of these metabolites are emerging as promising antibiotic targets. The recent description of an alternative pathway for polyamine synthesis, distinct from that in human cells, in C. jejuni suggests this pathway could be a target for novel therapies. To that end, we determined X-ray crystal structures of C. jejuni agmatine deiminase (CjADI) and demonstrated that loss of CjADI function contributes to antibiotic sensitivity, likely because of polyamine starvation. The structures provide details of key molecular features of the active site of this protein. Comparison of the unliganded structure (2.1 Å resolution) to that of the CjADI-agmatine complex (2.5 Å) reveals significant structural rearrangements that occur upon substrate binding. The shift of two helical regions of the protein and a large conformational change in a loop near the active site generate a narrow binding pocket around the bound substrate. This change optimally positions the substrate for catalysis. In addition, kinetic analysis of this enzyme demonstrates that CjADI is an iminohydrolase that effectively deiminates agmatine. Our data suggest that C. jejuni agmatine deiminase is a potentially important target for combatting antibiotic resistance, and these results provide a valuable framework for guiding future drug development.

  10. Mechanistic insights into landscape genetic structure of two tropical amphibians using field-derived resistance surfaces.

    Science.gov (United States)

    Nowakowski, A Justin; DeWoody, J Andrew; Fagan, Matthew E; Willoughby, Janna R; Donnelly, Maureen A

    2015-02-01

    Conversion of forests to agriculture often fragments distributions of forest species and can disrupt gene flow. We examined effects of prevalent land uses on genetic connectivity of two amphibian species in northeastern Costa Rica. We incorporated data from field surveys and experiments to develop resistance surfaces that represent local mechanisms hypothesized to modify dispersal success of amphibians, such as habitat-specific predation and desiccation risk. Because time lags can exist between forest conversion and genetic responses, we evaluated landscape effects using land-cover data from different time periods. Populations of both species were structured at similar spatial scales but exhibited differing responses to landscape features. Litter frog population differentiation was significantly related to landscape resistances estimated from abundance and experiment data. Model support was highest for experiment-derived surfaces that represented responses to microclimate variation. Litter frog genetic variation was best explained by contemporary landscape configuration, indicating rapid population response to land-use change. Poison frog genetic structure was strongly associated with geographic isolation, which explained up to 45% of genetic variation, and long-standing barriers, such as rivers and mountains. However, there was also partial support for abundance- and microclimate response-derived resistances. Differences in species responses to landscape features may be explained by overriding effects of population size on patterns of differentiation for poison frogs, but not litter frogs. In addition, pastures are likely semi-permeable to poison frog gene flow because the species is known to use pastures when remnant vegetation is present, but litter frogs do not. Ongoing reforestation efforts will probably increase connectivity in the region by increasing tree cover and reducing area of pastures. © 2014 John Wiley & Sons Ltd.

  11. Structures of HIV Protease Guide Inhibitor Design to Overcome Drug Resistance

    Energy Technology Data Exchange (ETDEWEB)

    Weber, Irene T.; Kovalevsky, Andrey Y.; Harrison, Robert W. (GSU)

    2008-06-03

    The HIV/AIDS infection continues to be a major epidemic worldwide despite the initial promise of antiviral drugs. Current therapy includes a combination of drugs that inhibit two of the virally-encoded enzymes, the reverse transcriptase and the protease. The first generation of HIV protease inhibitors that have been in clinical use for treatment of AIDS since 1995 was developed with the aid of structural analysis of protease-inhibitor complexes. These drugs were successful in improving the life span of HIV-infected people. Subsequently, the rapid emergence of drug resistance has necessitated the design of new inhibitors that target mutant proteases. This second generation of antiviral protease inhibitors has been developed with the aid of data from medicinal chemistry, kinetics, and X-ray crystallographic analysis. Traditional computational methods such as molecular mechanics and dynamics can be supplemented with intelligent data mining approaches. One approach, based on similarities to the protease interactions with substrates, is to incorporate additional interactions with main chain atoms that cannot easily be eliminated by mutations. Our structural and inhibition data for darunavir have helped to understand its antiviral activity and effectiveness on drug resistant HIV and demonstrate the success of this approach.

  12. Bioinformatics and structural characterization of a hypothetical protein from Streptococcus mutans: implication of antibiotic resistance.

    Directory of Open Access Journals (Sweden)

    Jie Nan

    2009-10-01

    Full Text Available As an oral bacterial pathogen, Streptococcus mutans has been known as the aetiologic agent of human dental caries. Among a total of 1960 identified proteins within the genome of this organism, there are about 500 without any known functions. One of these proteins, SMU.440, has very few homologs in the current protein databases and it does not fall into any protein functional families. Phylogenetic studies showed that SMU.440 is related to a particular ecological niche and conserved specifically in some oral pathogens, due to lateral gene transfer. The co-occurrence of a MarR protein within the same operon among these oral pathogens suggests that SMU.440 may be associated with antibiotic resistance. The structure determination of SMU.440 revealed that it shares the same fold and a similar pocket as polyketide cyclases, which indicated that it is very likely to bind some polyketide-like molecules. From the interlinking structural and bioinformatics studies, we have concluded that SMU.440 could be involved in polyketide-like antibiotic resistance, providing a better understanding of this hypothetical protein. Besides, the combination of multiple methods in this study can be used as a general approach for functional studies of a protein with unknown function.

  13. Thermal strain measurement of EAST W/Cu divertor structure using electric resistance strain gauges

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Xingli [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei, 230031 (China); Science Island Branch of Graduate School, University of Science & Technology of China, Hefei, 230031 (China); Wang, Wanjing, E-mail: wjwang@ipp.ac.cn [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei, 230031 (China); Wang, Jichao [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei, 230031 (China); Wei, Ran; Sun, Zhaoxuan [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei, 230031 (China); Science Island Branch of Graduate School, University of Science & Technology of China, Hefei, 230031 (China); Li, Qiang; Xie, Chunyi [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei, 230031 (China); Chen, Hong-En; Wang, Kaiqiang; Wu, Lei; Chen, Zhenmao [State Key Lab for Strength and Vibration of Mechanical Structures, Xi’an Jiaotong University (China); Luo, Guang-Nan [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei, 230031 (China); Science Island Branch of Graduate School, University of Science & Technology of China, Hefei, 230031 (China); Hefei Center for Physical Science and Technology, Hefei, 230022 (China); Hefei Science Center of Chinese Academy of Sciences, Hefei, 230027 (China)

    2016-12-15

    Highlights: • To understand the service behavior of W/Cu divertor, an electrical resistance strain gauge system had been introduced in a thermal strain measurement experiment. • The measurement system successfully finished the experiment and obtained valued thermal strain data. • Two thermomechanical analyses had also been carried out and compared with the measurement results. • Experiment results corresponded well to simulations and threw a light upon the failure of W/Cu divertor in the previous baking tests. - Abstract: W/Cu divertor has complex structure and faces extreme work environment in EAST Tokamak device. To measure its thermal strain shall be a valued way to understand its service behavior and then optimize its design and manufacturing process. This work presents a preliminary study on measuring thermal strain of EAST W/Cu divertor structure using electric resistance strain gauges. Eight gauges had been used in the experiment and the heating temperature had been set to 230 °C with respect to the work temperature. To realize the measuring experiment, an appropriate fixing method of gauges in divertor narrow spaces had been taken and tested, which could not only withstand high temperature but also had no damage to the divertor sample. The measurement results were that three gauges showed positive strain while other three showed negative strain after having been compensated, which corresponded to tensile stress and compressed stress respectively. Two thermomechanical simulations had also been carried out and used for comparing with the experiment.

  14. Analytical and numerical calculations of resistive wall impedances for thin beam pipe structures at low frequencies

    Energy Technology Data Exchange (ETDEWEB)

    Niedermayer, U., E-mail: u.niedermayer@gsi.de [Technische Universitaet Darmstadt, Institut fuer Theorie Elektromagnetischer Felder, Schlossgartenstrasse 8, 64289 Darmstadt (Germany); Boine-Frankenheim, O. [Technische Universitaet Darmstadt, Institut fuer Theorie Elektromagnetischer Felder, Schlossgartenstrasse 8, 64289 Darmstadt (Germany)

    2012-09-21

    The resistive wall impedance is one of the main sources for beam instabilities in synchrotrons and storage rings. The fast ramped SIS18 synchrotron at GSI and the projected SIS100 synchrotron for FAIR both employ thin (0.3 mm) stainless steel beam pipes in order to reduce eddy current effects. The lowest betatron sidebands are at about 100 kHz, which demands accurate impedance predictions in the low frequency (LF) range where the beam pipe and possibly also the structures behind the pipe are the dominating impedance sources. The longitudinal and transverse resistive wall impedances of a circular multi-layer pipe are calculated analytically using the field matching technique. We compare the impedances obtained from a radial wave model, which corresponds to the setup used in bench measurements, with the axial wave model, which corresponds to an actual beam moving with relativistic velocity. For thin beam pipes the induced wall current and the corresponding shielding properties of the pipe are important. In both models the wall current is obtained analytically. The characteristic frequencies for the onset of the wall current are calculated from equivalent lumped element circuits corresponding to the radial model. For more complex structures, like the SIS100 beam pipe, we use a numerical method, in which the impedance is obtained from the total power loss. The method is validated by the analytic expressions for circular beam pipes.

  15. Evaluation of different measurements for effective thermal conductivity of fibrous materials

    Directory of Open Access Journals (Sweden)

    Tian Ming-Wei

    2014-01-01

    Full Text Available Effective thermal conductivity is generally recognized as the intrinsic factor to reveal the thermal responses of fibrous materials. Here, two typical measurements, the step-wise transient method and the guarded hot plate method, were utilized to identify their feasibility for the effective thermal conductivity of fibrous materials (non-woven fabric and twill fabric with different stacking layers.

  16. Low level hydrogen peroxide generation from a nonwoven fibrous pectin-cellulose blend

    Science.gov (United States)

    Fibrous pectic-cellulose (FPC) (cellulose blended with primary cell wall pectin at 2 percent by weight of pectin) is product made from naturally occurring plant fibers. FPC is a fibrous mixture of polysaccharides with a low percent by weight of pectin-based primary cell wall and lipid components att...

  17. High-surface-area silica nanospheres (KCC-1) with a fibrous morphology

    KAUST Repository

    Polshettiwar, Vivek

    2010-08-02

    Fibrous nanosilica: A new family of high-surface-area silica nanospheres (KCC-1) have been prepared (see picture). KCC-1 features excellent physical properties, including high surface area, unprecedented fibrous surface morphology, high thermal (up to 950 °C) and hydrothermal stabilities, and high mechanical stability. Copyright © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Malignant solitary fibrous tumor in anterior mediastinum with pleural metastasis simulating invasive thymoma

    International Nuclear Information System (INIS)

    Kim, Jong Bum; Lee, Ju Won; Kim, Youn Jeong; Kim, Yeo Ju; Lee, Kyung Hee; Chu, Young Chae; Song, Ju Young; Yoon, Yong Han

    2012-01-01

    Malignant solitary fibrous tumor, which arises in the anterior mediastinum, is rare. Its image findings simulate other mediastinal mass, such as malignant lymphoma, malignant thymic epithelial tumor or invasive thymoma. Here, we report a pleural malignant fibrous tumor of a 60 year old man who is presented with a well defined lobulating anterior mediastinal mass with pleural metastasis mimicking invasive thymoma with pleural seeding

  19. Malignant solitary fibrous tumor in anterior mediastinum with pleural metastasis simulating invasive thymoma

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jong Bum; Lee, Ju Won; Kim, Youn Jeong; Kim, Yeo Ju; Lee, Kyung Hee; Chu, Young Chae; Song, Ju Young; Yoon, Yong Han [Inha Univ. School of Medicine/Inha Univ. Hospital, Incheon (Korea, Republic of)

    2012-05-15

    Malignant solitary fibrous tumor, which arises in the anterior mediastinum, is rare. Its image findings simulate other mediastinal mass, such as malignant lymphoma, malignant thymic epithelial tumor or invasive thymoma. Here, we report a pleural malignant fibrous tumor of a 60 year old man who is presented with a well defined lobulating anterior mediastinal mass with pleural metastasis mimicking invasive thymoma with pleural seeding.

  20. Evaluation of Chemical Structure and Resistance Switching Characteristics of Undoped Titanium Oxide and Titanium-Yttrium Mixed Oxide

    Science.gov (United States)

    Ohta, Akio; Goto, Yuta; Wei, Guobin; Murakami, Hideki; Higashi, Seiichiro; Miyazaki, Seiichi

    2011-10-01

    We have studied the chemical bonding features in the region near the TiO2/Pt interface after resistance change to gain a better understanding of the mechanism of resistance switching in TiO2-based resistance random access memory (ReRAM). For the Pt/TiO2/Pt structure after resistance switching, oxidation of the Pt electrode at the Pt/TiO2 interface in switching from a high resistance state (HRS) to a low resistance state (LRS) and reduction of this Pt-oxide in switching from the LRS to the HRS were observed by hard X-ray photoelectron spectroscopy. The result suggests that the generation of oxygen vacancies in the Ti-oxide matrix is responsible for the formation of the conductive pass resulting in the LRS and that repeatable redox reaction at the Pt/TiO2 interface plays an important role in resistance switching behavior. To modify the oxide network, which leads to the change in the conduction pass formation, trivalent Y ions were added to the oxide matrix of quadrivalent Ti ions. Raman scattering and X-ray diffraction measurements show that the crystallization of TiO2 by thermal annealing was suppressed by the Y2O3 addition. In Au/TiYxOy/Pt structures, it has been demonstrated that the variations in resistance switching voltages are markedly suppressed by the Y2O3 addition to TiO2.

  1. Pulping and papermaking properties of the leaf fiber and fibrous residue from Agave tequilana

    Energy Technology Data Exchange (ETDEWEB)

    Kurita, T.; Mitsuhashi, S.; Kanetsuna, H.; Iguchi, M.; Shirota, T.; Trujillo, J.J.; Herrera, T.

    1981-01-01

    The leaves and fibrous residue of A. tequilana had fibriles with parallel orientation and helical arrangement to the fiber axis and contained fibers in average length and width of 1.7 mm and 10.3 mu m and 0.8 mm and 25.5 mu m, respectively. The cell wall in leaves was thicker and narrower than those in fibrous residue, and leaves contained cellulose and lignin lower than fibrous residue did. Alkali sulfite cooking of leaves gave pulp, the yield of which was lower than that from fibrous residue. The H/sub 2/On retention and bulk density of leaf pulps increased rapidly on beating suggesting that an internal fibrillation in pulp occurs easily during beating. The breaking length and burst and tear factors of paper from leaf pulp were higher than those from fibrous residue.

  2. Analysis for the depth of underground resistivity structure by using MT method

    International Nuclear Information System (INIS)

    Matsuo, Koichi; Yokoi, Koichi; Negi, Tateyuki; Kasagi, Toshio; Takahashi, Takeharu; Teshima, Minoru

    2005-03-01

    was admitted, and the unexpected value was removed. The standard deviation was 10% or less except 320 Hz, 0.094 Hz and 0.00055 Hz. 7) Effect of earthquake was studied. Seismic amplitude was recalculated from earthquake magnitude and distance from the epicenter. As a result, resistivity did not change before and behind the earthquake, this means underground water and underground structure were stable. 8) Resistivity change of the long term was calculated by the moving average of 41 days. As a result, resistivity change similar with the outside temperature was observed at some frequency. It is uncertain that this cause was seasonal change of underground water or temperature characteristic of equipment. It is necessary to accumulate data to judge this cause. (author)

  3. Microstructure and Wear Resistance of Al2O3 Coatings on Functional Structure

    Directory of Open Access Journals (Sweden)

    Jiang Chao-Ping

    2016-01-01

    Full Text Available To enhance the wear properties of function structure, Al2O3-13%TiO2 (AT13 coatings were plasma sprayed on 45 steel functional structure using micro and nano powders. The microstructures and phase compositions of the coatings were investigated by scanning electron microscopy and X-ray diffraction, respectively. Results show that the nano powder coating consists of fully-melted region and partially-melted region. The fully-melted regions show a lamellar structure, while the partially-melted regions retain the powders structure. The phases of coatings are α-A12O3 and TiO2.The wear test was carried out on a ML-10 friction and wear tester under dry sliding condition. It is found that the wear resistance of the micro powder coating is higher than that of nano powder coating. This is mainly ascribe to the breakage of the nano powder coating resulted from low agglomerated binding force.

  4. Evaluation of polyacrylonitrile electrospun nano-fibrous mats as leukocyte removal filter media.

    Science.gov (United States)

    Pourbaghi, Raha; Zarrebini, Mohammad; Semnani, Dariush; Pourazar, Abbasali; Akbari, Nahid; Shamsfar, Reihaneh

    2017-09-13

    Removal of leukocytes from blood products is the most effective means for elimination of undesirable side effects and prevention of possible reactions in recipients. Micro-fibrous mats are currently used for removal of leukocytes from blood. In this study, samples of electrospun nano-fibrous mats were produced. The performance of the produced electrospun nano-fibrous mats as means of leukocytes removal from fresh whole blood was both evaluated and compared with that of commercially available micro-fibrous mats. In order to produce the samples, polyacrylonitrile (PAN) nano-fibrous mats were made under different electrospinning conditions. Mean fiber diameter, pore characterization and surface roughness of the PAN nano-fibrous mats were determined using image processing technique. In order to evaluate the surface tension of the fabricated mats, water contact angle was measured. The leukocyte removal performance, erythrocytes recovery percent and hemolysis rate of the nano-fibrous mats were compared. The effectiveness of nano-fibrous mats in removing leukocyte was established using both scanning electron microscope and optical microscope. Results showed that for given weight, the fabricated nano-fibrous mats were not only more efficient but also more cost-effective than their commercial counterparts. Results confirmed that changes in mean fiber diameter, the number of layer and weight of each layer in the absence of any chemical reaction or physical surface modification, the fabricated nano-fibrous mats were able to remove 5-log of leukocytes. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2017. © 2017 Wiley Periodicals, Inc.

  5. Structural and Functional Adaptation of Vancomycin Resistance VanT Serine Racemases.

    Science.gov (United States)

    Meziane-Cherif, Djalal; Stogios, Peter J; Evdokimova, Elena; Egorova, Olga; Savchenko, Alexei; Courvalin, Patrice

    2015-08-11

    Vancomycin resistance in Gram-positive bacteria results from the replacement of the D-alanyl-D-alanine target of peptidoglycan precursors with D-alanyl-D-lactate or D-alanyl-D-serine (D-Ala-D-Ser), to which vancomycin has low binding affinity. VanT is one of the proteins required for the production of D-Ala-D-Ser-terminating precursors by converting L-Ser to D-Ser. VanT is composed of two domains, an N-terminal membrane-bound domain, likely involved in L-Ser uptake, and a C-terminal cytoplasmic catalytic domain which is related to bacterial alanine racemases. To gain insight into the molecular function of VanT, the crystal structure of the catalytic domain of VanTG from VanG-type resistant Enterococcus faecalis BM4518 was determined. The structure showed significant similarity to type III pyridoxal 5'-phosphate (PLP)-dependent alanine racemases, which are essential for peptidoglycan synthesis. Comparative structural analysis between VanTG and alanine racemases as well as site-directed mutagenesis identified three specific active site positions centered around Asn696 which are responsible for the L-amino acid specificity. This analysis also suggested that VanT racemases evolved from regular alanine racemases by acquiring additional selectivity toward serine while preserving that for alanine. The 4-fold-lower relative catalytic efficiency of VanTG against L-Ser versus L-Ala implied that this enzyme relies on its membrane-bound domain for L-Ser transport to increase the overall rate of d-Ser production. These findings illustrate how vancomycin pressure selected for molecular adaptation of a housekeeping enzyme to a bifunctional enzyme to allow for peptidoglycan remodeling, a strategy increasingly observed in antibiotic-resistant bacteria. Vancomycin is one of the drugs of last resort against Gram-positive antibiotic-resistant pathogens. However, bacteria have evolved a sophisticated mechanism which remodels the drug target, the D-alanine ending precursors in cell wall

  6. Plasmodium falciparum parasite population structure and gene flow associated to anti-malarial drugs resistance in Cambodia.

    Science.gov (United States)

    Dwivedi, Ankit; Khim, Nimol; Reynes, Christelle; Ravel, Patrice; Ma, Laurence; Tichit, Magali; Bourchier, Christiane; Kim, Saorin; Dourng, Dany; Khean, Chanra; Chim, Pheaktra; Siv, Sovannaroth; Frutos, Roger; Lek, Dysoley; Mercereau-Puijalon, Odile; Ariey, Frédéric; Menard, Didier; Cornillot, Emmanuel

    2016-06-14

    Western Cambodia is recognized as the epicentre of emergence of Plasmodium falciparum multi-drug resistance. The emergence of artemisinin resistance has been observed in this area since 2008-2009 and molecular signatures associated to artemisinin resistance have been characterized in k13 gene. At present, one of the major threats faced, is the possible spread of Asian artemisinin resistant parasites over the world threatening millions of people and jeopardizing malaria elimination programme efforts. To anticipate the diffusion of artemisinin resistance, the identification of the P. falciparum population structure and the gene flow among the parasite population in Cambodia are essential. To this end, a mid-throughput PCR-LDR-FMA approach based on LUMINEX technology was developed to screen for genetic barcode in 533 blood samples collected in 2010-2011 from 16 health centres in malaria endemics areas in Cambodia. Based on successful typing of 282 samples, subpopulations were characterized along the borders of the country. Each 11-loci barcode provides evidence supporting allele distribution gradient related to subpopulations and gene flow. The 11-loci barcode successfully identifies recently emerging parasite subpopulations in western Cambodia that are associated with the C580Y dominant allele for artemisinin resistance in k13 gene. A subpopulation was identified in northern Cambodia that was associated to artemisinin (R539T resistant allele of k13 gene) and mefloquine resistance. The gene flow between these subpopulations might have driven the spread of artemisinin resistance over Cambodia.

  7. Fabrication of two-dimensional visible wavelength nanoscale plasmonic structures using hydrogen silsesquioxane based resist

    Science.gov (United States)

    Smith, Kyle Z.; Gadde, Akshitha; Kadiyala, Anand; Dawson, Jeremy M.

    2016-03-01

    In recent years, the global market for biosensors has continued to increase in combination with their expanding use in areas such as biodefense/detection, home diagnostics, biometric identification, etc. A constant necessity for inexpensive, portable bio-sensing methods, while still remaining simple to understand and operate, is the motivation behind novel concepts and designs. Labeled visible spectrum bio-sensing systems provide instant feedback that is both simple and easy to work with, but are limited by the light intensity thresholds required by the imaging systems. In comparison, label-free bio-sensing systems and other detection modalities like electrochemical, frequency resonance, thermal change, etc., can require additional technical processing steps to convey the final result, increasing the system's complexity and possibly the time required for analysis. Further decrease in the detection limit can be achieved through the addition of plasmonic structures into labeled bio-sensing systems. Nano-structures that operate in the visible spectrum have feature sizes typically in the order of the operating wavelength, calling for high aspect ratio nanoscale fabrication capabilities. In order to achieve these dimensions, electron beam lithography (EBL) is used due to its accurate feature production. Hydrogen silsesquioxane (HSQ) based electron beam resist is chosen for one of its benefits, which is after exposure to oxygen plasma, the patterned resist cures into silicon dioxide (SiO2). These cured features in conjunction with nanoscale gold particles help in producing a high electric field through dipole generation. In this work, a detailed process flow of the fabrication of square lattice of plasmonic structures comprising of gold coated silicon dioxide pillars designed to operate at 560 nm wavelength and produce an intensity increase of roughly 100 percent will be presented.

  8. Rare giant frontal sinus osteoma mimicking fibrous dysplasia.

    Science.gov (United States)

    Exley, R P; Markey, A; Rutherford, S; Bhalla, R K

    2015-03-01

    To present the first report of a giant frontal sinus osteoma treated by excision and single-stage reconstruction with custom-made titanium cranioplasty and left orbital roof prostheses. A 31-year-old man with a history of chronic frontal sinusitis presented with a deforming, painless, midline forehead swelling of 11 years' duration, which had been treated unsuccessfully in Nigeria. Differential diagnosis included both benign and malignant bony tumours. Computerised tomography revealed a giant bony frontal sinus tumour extending beyond the sinus roof and breaching the left orbit, consistent with fibrous dysplasia. Given the extent of the tumour, open craniectomy was performed for surgical extirpation. Histological analysis identified multiple osteomas. This surgical approach achieved excellent cosmesis, with no evidence of recurrence at 12-month follow up. Forehead swelling may pose diagnostic and management dilemmas for the ENT surgeon; however, effective management is facilitated by a multidisciplinary approach.

  9. Intramuscular myxoma and fibrous dysplasia of bone - Mazabraud's syndrome

    International Nuclear Information System (INIS)

    Court-Payen, M.; Ingemann Jensen, L.; Bjerregaard, B.; Schwarz Lausten, G.; Skjoldbye, B.

    1997-01-01

    We present a case of Mazabroud's syndrome, a rare benign disease, with multiple intramuscular myxomas of the thoracic wall associated with fibrous dysplasia of bone. CT, MR imaging and ultrasonography (US) of the thorax showed 2 well circumscribed homogeneous intramuscular tumors. A US-guided needle biopsy with a large-core needle (2.0 mm) and a fine needle (0.8 mm) showed that the tumors were intramuscular myxomas with no sign of malignancy. 99m Tc bone scintigraphy showed a markedly increased uptake in the right lower skull, and multiple smaller foci. CT of the skull revealed a right-sided unilateral bone thickening of the orbit and the ethomoidal cells, and right-sided exophthalmia. This case history suggests that patients with multiple intramuscular myxomas should be preoperatively examined for osseous lesions. A postoperative follow-up should also be performed to detect other soft-tissue myxomas not as yet clinically detectable, or rare osseous complications. (orig.)

  10. Focal fibrous overgrowths: A case series and review of literature

    Directory of Open Access Journals (Sweden)

    Abhay P Kolte

    2010-01-01

    Full Text Available Intraoral fibrous overgrowths of the soft tissues are relatively common and may be benign reactive or neoplastic lesions. A series of 10 lesions is presented which included pyogenic granuloma, fibroma and peripheral ossifying fibroma. Almost all the lesions occurred in the second and third decades and were present in the anterior segment of the jaws, with a distinct female predilection. Majority of these lesions were asymptomatic and the patients reported for treatment only due to the discomfort during function. Histopathologic examinations were done for diagnosis of these lesions. Surgical excision along with removal of causative irritants remains the treatment of choice. The extent of excision should depend on the severity of the lesion, as some of these lesions have a tendency for recurrence. All the patients in this series were closely followed up for a period of 2 years and showed no signs of recurrence.

  11. Malignant Fibrous Histiocytoma of the Breast: A Case Report

    Directory of Open Access Journals (Sweden)

    Dimosthenis Miliaras

    2012-01-01

    Full Text Available This paper concerns a case of Malignant Fibrous Histiocytoma (MFH of the Breast in a 73-years-old woman. A lump was found in her right breast, measuring 1.7 cm in diameter. Surgical excision followed, and pathology revealed a highly atypical spindle cell tumor. Immunohistochemistry along the histological features, excluded the possibility of carcinoma, malignant phyllodes tumor, or another type of pure sarcoma. There was no history of previous irradiation in the region. MFH is among the rarest types of sarcoma of the breast, and most of the times behaves aggressively. Excision with wide, free-of-tumor margins is the most effective treatment, when feasible.

  12. A postirradiation, myxoid type, malignant fibrous histiocytoma; A case report

    Energy Technology Data Exchange (ETDEWEB)

    Takeuchi, Masaki; Higuchi, Ryouhei; Ohsige, Kenji; Kouya, Michiko (Tokyo Metropolitan Fuchu Hospital, Tokyo (Japan)); Nozaki, Motohiro

    1993-09-01

    The authors discuss the case of a 59-year-old man who presented a mass in the dorsum of his right foot. He previously had had a hemangioma in this region from birth, and at the age of 10, radiation therapy had been administered to this region because of an ulcer that had developed. Additionally, so as to cover the ulcer, he had been given a free skin graft and a cross-leg flap. Some 50 years after this radiation, he noticed a mass in his foot, and a microscopic examination of a biopsied specimen of this mass revealed it to be a myxoid type, malignant fibrous histiocytoma (MFH). Thus, a below-the-knee amputation was performed. To the best of their knowledge, the authors report that 29 cases of an MFH developing after radiotherapy have been reported in the Japanese literature, and an analysis of these 29 cases is provided and the details of this case are given. (author).

  13. Mishmash Impression Technique for Managing Maxillary Anterior Fibrous Ridge

    Directory of Open Access Journals (Sweden)

    Poonam Kulkarni

    2018-06-01

    Full Text Available Introduction: Flabby or fibrous ridge is one of the consequences of long term wearing of complete dentures. It can develop where hyperplasic soft tissue replaces the alveolar bone and is a common finding, particularly in the upper anterior region of long term denture wearers. Forces exerted during impression making can result in distortion of the mobile tissue unless managed appropriately; such flabby ridges adversely affect support, retention and stability of complete dentures. Many impression techniques have been developed to help overcome this problem. While these vary in the method applied, they are similar in their complexity, are often quite time-consuming to perform and rely on materials not commonly used in contemporary general dental practice. The purpose of this article is to describe an impression technique for flabby ridges usingrubber base impression materials, routinely available in general dental practice.

  14. Idiopathic hypothalamic hypogonadotropic hypogonadism with polyostotic fibrous dysplasia.

    Science.gov (United States)

    Shires, R; Whyte, M P; Avioli, L V

    1979-10-01

    A 22-year-old woman had polyostotic fibrous dysplasia (POFD) and idiopathic hypothalamic hypogonadotropic hypogonadism (isolated gonadotropin deficiency). Recurrent fracture of dysplastic bone during childhood was associated with primary amenorrhea, clinical and laboratory evidence of estrogen deficiency, and subnormal circulating and urinary gonadotropin levels during adolescence. Gonadorelin (luteinizing hormone-releasing hormone) stimulation initially showed a luteinizing hormone (LH) response but absent follicle-stimulating hormone (FSH) response. After three months without estrogen and progesterone and after four days of gonadorelin "priming," a subsequent gonadorelin infusion produced an enhanced LH and FSH response. All other tests of peripheral and trophic hormone levels and pituitary trophic hormone reserves were normal. Whereas POFD is known to occur with sexual precocity and other endocrinopathies, to our knowledge this is the first report of its association with isolated gonadotropin deficiency.

  15. A theoretical analysis of local thermal equilibrium in fibrous materials

    Directory of Open Access Journals (Sweden)

    Tian Mingwei

    2015-01-01

    Full Text Available The internal heat exchange between each phase and the Local Thermal Equilibrium (LTE scenarios in multi-phase fibrous materials are considered in this paper. Based on the two-phase heat transfer model, a criterion is proposed to evaluate the LTE condition, using derived characteristic parameters. Furthermore, the LTE situations in isothermal/adiabatic boundary cases with two different heat sources (constant heat flux and constant temperature are assessed as special transient cases to test the proposed criterion system, and the influence of such different cases on their LTE status are elucidated. In addition, it is demonstrated that even the convective boundary problems can be generally estimated using this approach. Finally, effects on LTE of the material properties (thermal conductivity, volumetric heat capacity of each phase, sample porosity and pore hydraulic radius are investigated, illustrated and discussed in our study.

  16. Solitary fibrous tumor of the liver: a case report

    Directory of Open Access Journals (Sweden)

    Ying Li-Xiong

    2011-03-01

    Full Text Available Abstract Hepatic solitary fibrous tumor (SFT is a rare tumor originating from the mesenchyme. Here we report a new case of SFT in the liver and review the clinical presentation, radiological and operative findings, diagnosis, treatment, and outcome. The patient was a 59-year-old man who presented with progressive fatigue for 3 months and an abdominal mass for 3 days. On laboratory tests, no abnormality was detected except that abdominal ultrasonography revealed a 9.0 × 6.2 cm hypoechogenic mass in the left lobe of the liver. A computed tomographic scan confirmed a hypodense lesion in the left lobe of the liver. The patient underwent left hepatectomy. SFT was diagnosed on the basis of histopathological findings. The patient was free from all symptoms and had no signs of local recurrence after 24 months' follow up.

  17. Giant Solitary Fibrous Tumor of the Parotid Gland

    Directory of Open Access Journals (Sweden)

    Octavian Chis

    2014-01-01

    Full Text Available Solitary fibrous tumors (SFTs are rare tumors that are mostly found arising from the pleura. SFT of the parotid gland is a rare tumor; only a few cases have been described in the literature. SFTs are benign in most cases. Clinically, SFTs usually manifest as well circumscribed, slow-growing, smooth, and painless masses. CT-Scan and MRI are the most sensitive imaging procedures used. The treatment of choice is complete surgical excision of the lesion. Since recurrence and metastasis can take place after several years, a lifelong clinical and imaging regular follow-up is compulsory. In this paper, we describe the diagnostic and therapeutic challenges of the up-to-now biggest parotid SFT. The clinical presentation, surgical management, and pathological and immunohistochemistry findings are described.

  18. Pentazocine-induced leg ulcers and fibrous papules

    Directory of Open Access Journals (Sweden)

    De Dipankar

    2007-01-01

    Full Text Available We herein describe a case of 55-year-old farmer, who presented with chronic non-healing ulcers over both shins of 4 years duration. Intravenous drug abuse was suspected due to inability to find any venous access and all peripheral veins being found thickened and fibrosed. There were multiple atrophic scars in linear distribution in all limbs as well as in both groins. In addition there were multiple discrete fibrous papules in linear distribution on both hands, which were more obvious on the left side. The patient denied abusing intravenous drugs. However, his relatives confirmed that he abused pentazocine for almost one year before his chronic pain in abdomen was treated by appendicectomy. With subsequent counseling, it was found that he continued to abuse pentazocine at times even after surgery leading to the non-healing of ulcers.

  19. Case report 490: Monostotic fibrous dysplasia of the pubis

    Energy Technology Data Exchange (ETDEWEB)

    Buckwalter, J.A.; El-Khoury, G.; Bonfiglio, M.M.; Platz, C.C.

    1988-07-01

    An expansile lesion of the superior pubic ramus in a 32 year old man was discovered incidentally when roentgenograms were obtained to assess the possibility of fracture following an automobile accident. A technetium scan showed increased uptake in the lesion and computed tomography showed expansion of the superior pubic ramus and extension of the lesion from the pubic symphysis to the acetabulum. A needle aspirate of the lesion consisted of blood and giant cells. Based on the appearance of the lesion and the needle aspirate a preliminary diagnosis of giant cell tumor or aneurysmal bone cyst was made. When examined at the time of operation, the lesion was found to be firm and gritty. It was removed and the remaining bone surfaces curetted. Histological examination showed a pattern most consistent with fibrous dysplasia. The pubic ramus healed uneventfully.

  20. Solitary fibrous tumor of the pleura: 3 case reports

    Directory of Open Access Journals (Sweden)

    Elias Amorim

    2015-06-01

    Full Text Available Summary Introduction: solitary fibrous tumor of the pleura (SFTP is a rare tumor arising from mesenchymatous cells in submesothelial pleural tissue which, unlike mesothelioma, is not related to asbestos or smoking. Methods: report of four patients who underwent surgical treatment for giant SFTP and review of the pertinent literature. Results: of the four patients operated, two presented symptoms including cough, chest pain and feeling of compression, whereas the other two subjects were asymptomatic. All patients underwent complete surgical resection by wide posterolateral thoracotomy, and surgical specimens removed with minimum bleeding. None of the cases required complementary lobectomy or segmentectomy. All tumors were histologically benign. Conclusion: complete resection of the lesion is the treatment of choice in all SFTP cases. Prognosis of the benign lesion is excellent, although close follow-up is necessary. In the rarer, more aggressive forms, treatment may be complemented by adjunctive chemotherapy or radiotherapy, the benefits of which have yet to be confirmed.

  1. Hypoglyceamia in a Patient with a Solitary Fibrous Tumour

    Directory of Open Access Journals (Sweden)

    Andrew Okpe

    2016-04-01

    Full Text Available Objective: To illustrate an unusual mechanism causing hypoglycaemia. Material and methods: A 76-year-old man presented with episodes of agitation and confusion and was resuscitated with oral glucose gel when found to be hypoglycaemic. Results: A CT scan for an abdominal mass confirmed a solitary fibrous tumour (SFT. The sarcoma multidisciplinary team suggested conservative management. The patient's episodic hypoglycaemia was managed with diet modification including corn-based starch, scheduled snacks and dexamethasone. Glucose levels were within normal range at discharge from hospital. The patient was referred to the palliative care team for follow-up. Conclusion: SFTs causing non-islet cell tumour hypoglycaemia are difficult to treat.

  2. Primary Malignant Fibrous Histiocytoma of the Lung: A Case Report

    Directory of Open Access Journals (Sweden)

    Chuan-Sheng Wang

    2003-08-01

    Full Text Available Malignant fibrous histiocytoma (MFH is the most common soft tissue sarcoma in adults. However, primary MFH of the lung is rare, with only a few cases reported in the literature. Here, we report the case of an 86-year-old male who was admitted to our hospital with the chief complaint of exertional dyspnea and poor appetite. Chest roentgenography revealed a 9 × 15 cm, pleural-based opacity in the left lower lobe. Chest computerized tomography disclosed a well-defined mass with heterogeneous density in the left lower lung field. The diagnosis of MFH was confirmed by thoracoscopic lung biopsy and pathologic examination. Supportive care was given because of extreme old age and poor performance status (the patient's Karnofsky performance status was 30. The patient died from respiratory failure 2 months later.

  3. Bioactive Nano-fibrous Scaffold for Vascularized Craniofacial Bone Regeneration

    DEFF Research Database (Denmark)

    Prabha, Rahul Damodaran; Kraft, David Christian Evar; Harkness, Linda

    2018-01-01

    There has been a growing demand for bone grafts for correction of bone defects in complicated fractures or tumors in the craniofacial region. Soft flexible membrane like material that could be inserted into defect by less invasive approaches; promote osteoconductivity and act as a barrier to soft...... tissue in growth while promoting bone formation is an attractive option for this region. Electrospinning has recently emerged as one of the most promising techniques for fabrication of extracellular matrix (ECM) like nano-fibrous scaffolds that can serve as a template for bone formation. To overcome...... and biocompatibility properties of the new scaffold material. Our results indicate PVA-PCL-HAB scaffolds support attachment and growth of stromal stem cells; (human bone marrow skeletal (mesenchymal) stem cells (hMSC) and dental pulp stem cells (DPSC)). In addition, the scaffold supported in vitro osteogenic...

  4. Determination of physical properties of fibrous thermal insulation

    Directory of Open Access Journals (Sweden)

    Jeandel G.

    2012-10-01

    Full Text Available The objective of this study is to characterize both experimentally and theoretically, conductive and radiative heat transfer within polyester batting. This material is derived from recycled bottles (PET with fibres of constant diameters. Two other mineral and plant fibrous insulation materials, (glass wool and hemp wool are also characterized for comparative purposes. To determine the overall thermophysical properties of the tested materials, heat flux measurement are carried out using a device developed in house. The radiative properties of the material are determined by an inverse method based on measurements of transmittance and reflectance using a FTIR spectrometer and by solving the equation of radiative heat transfer. These measures are compared to results of numerical simulations.

  5. Factors influencing the survival and leaching of tetracycline-resistant bacteria and Escherichia coli through structured agricultural fields

    DEFF Research Database (Denmark)

    Bech, Tina Bundgaard; Rosenbom, Annette E.; Kjær, Jeanne

    2014-01-01

    Intense use of antibiotics in agricultural production may lead to the contamination of surface and groundwater by antibiotic-resistant bacteria. In the present study, the survival and leaching of E. coli and tetracycline-resistant bacteria were monitored at two well-structured agricultural fields....... Non-spiked pig slurry was injected in accordance with agricultural practice in the area. In both fields, the concentration of E. coli and tetracycline-resistant bacteria in the injected part of the plough layer decreased to the detection limit within 46–49 days. At Silstrup the decay was initiated...... with a lag phase and a decimal reduction time of 16 days for E. coli and 18 days for tetracycline-resistant bacteria. At Estrup the decay was immediate and the decimal reduction time was 22 days for E .coli and 26 days for tetracycline-resistant bacteria. Despite the two fields being prone to rapid...

  6. Electrical resistivity imaging of the near-surface structure of the Solfatara volcano

    Science.gov (United States)

    Giulia Di Giuseppe, Maria; Troiano, Antonio; Fedele, Alessandro; Patella, Domenico; Troise, Claudia; De Natale, Giuseppe

    2014-05-01

    We describe the results from an high-resolution study of the near-surface electrical resistivity structures carried out in the Solfatara area, located in the central part of the Campi Flegrei (CF) composite caldera, west of Naples, Italy. This area represents the most active zone within the CF area. It has been the site of an intense hydrothermal activity since Greek times, and currently exhibits the most impressive degassing manifestations. A direct relationship has always been observed between the increase of hydrothermal activity and ground uplift in the caldera. For this reason, dynamic of the Solfatara zone is considered a direct indicator of the volcanism taking place in the CF caldera. Since 2005 a new gradual increase of the hydrothermal activity and ground uplift has been observed. A steep growth of these effects has been recorded from 2012, accompanied by seismic events with hypocentres mostly concentrated below the area of Pozzuoli at depths ranging between 1 and 3 km, and highest magnitude of 1.8. It is thought that a further increase of the activity might lead to more critical conditions, including the occurrence of phreatic explosions. The detailed recovery of the structure and features of the shallow aquifers, mainly in the largest fumarole areas, is a crucial step for interpreting the ground movements and to improve our capability to forecast future pre-eruptive scenarios. Electrical resistivity results particularly sensitive to the presence of aqueous fluids and partial melts. By electrical imaging the volume of subsurface fluids can be constrained and the rheology of the subsoil can be reconstructed. To this aim, we have carried out eight profiles for electrical resistivity imaging, crossing the fumaroles field, deducting an electric model of the structural setting of the hydrothermal system in the first 100 m depth. Six of the profiles were 250 m long, with an electrodic distance of 5 m. Two longer profiles, up to 750 m, characterised by an

  7. Resistivity structure of the Furnas hydrothermal system (Azores archipelago, Portugal) from AMT and ERT imaging.

    Science.gov (United States)

    Byrdina, Svetlana; Vandemeulebrouck, Jean; Rath, Volker; Silva, Catarina; Hogg, Colin; Kiyan, Duygu; Viveiros, Fatima; Eleuterio, Joana; Gresse, Marceau

    2016-04-01

    The Furnas volcanic complex is located in the eastern part of the São Miguel Island and comprises a 5 km × 8 km summit depression filled by two nested calderas with several craters and a lake. Present-day volcanic activity of Furnas volcano is mostly located in the northern part of the caldera, within the Furnas village and north to Furnas Lake, where hydrothermal manifestations are mainly fumarolic fields, steam vents, thermal springs, and intense soil diffuse degassing. Considering the Furnas volcano as a whole, the total integrated CO2 efflux is extremely high, with a total amount of CO2 close to 1000 ton per day (Viveiros et al., 2009). We present the first results of an electrical resistivity tomography (ERT), combined with audio-magneto-telluric (AMT) measurements aligned along two profiles inside the caldera. The purpose of this survey is to delimit the extent, the geometry, and the depth of the hydrothermal system and to correlate the deep resistivity structure with high resolution cartography of diffuse CO2 flux (Viveiros et al, 2015). The ERT and AMT methods are complementary in terms of resolution and penetration depth: ERT can image the structural details of shallow hydrothermal system (down to 100 m in our study) while AMT can image at lower resolution deeper structures at the roots of a volcano (down to 4 km in our study). Our first independent 2D inversions of the ERT-AMT data show a good agreement between the surficial and deeper features. Below the main fumarole area we observe a low resistivity body (less than 1 Ohmm) which corresponds well to the high CO2 flux at the surface and is associated with an extended conductive body at larger depth. These results strongly suggest the presence of hydrothermal waters at depth or/and the presence of altered clay-rich material. On a larger scale however, the geometry of the conducting zones differs slightly from what was expected from earlier surface studies, and may not be directly related to fault zones

  8. Impact of Vat resistance in melon on viral epidemics and genetic structure of virus populations.

    Science.gov (United States)

    Schoeny, Alexandra; Desbiez, Cécile; Millot, Pauline; Wipf-Scheibel, Catherine; Nozeran, Karine; Gognalons, Patrick; Lecoq, Hervé; Boissot, Nathalie

    2017-09-15

    Cultivar choice is at the heart of cropping systems and resistant cultivars should be at the heart of disease management strategies whenever available. They are the easiest, most efficient and environmentally friendly way of combating viral diseases at the farm level. Among the melon genetic resources, Vat is a unique gene conferring resistance to both the melon aphid Aphis gossypii and the viruses it carries. The 'virus side' of this pleiotropic phenotype is seldom regarded as an asset for virus control. Indeed, the effect of Vat on virus epidemics in the field is expected to vary according to the composition of aphid populations in the environment and long-term studies are needed to draw a correct trend. Therefore, the first objective of the study was to re-evaluate the potential of Vat to reduce viral diseases in melon crops. The second objective was to investigate the potential of Vat to exert a selection pressure on virus populations. We monitored the epidemics of Cucurbit aphid-borne yellows virus (CABYV), Cucumber mosaic virus (CMV), Watermelon mosaic virus (WMV) and Zucchini yellow mosaic virus (ZYMV) in two melon lines having a common genetic background, a resistant line (R) and a susceptible line (S), in eight field trials conducted in southeastern France between 2011 and 2015. Vat had limited impact if any on WMV epidemics probably because A. gossypii is not the main vector of WMV in the field, but a favorable impact on CMV, yet of variable intensity probably related to the importance of A. gossypii in the total aphid population. Vat had a significant impact on CABYV epidemics with mean incidence reduction exceeding 50% in some trials. There was no effect of Vat on the structure of virus populations, both for the non-persistent WMV transmitted by numerous aphid species and for the persistent CABYV transmitted predominantly by A. gossypii. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. Structure and corrosion resistance of nickel coatings containing tungsten and silicon powders

    International Nuclear Information System (INIS)

    Popczyk, Magdalena; Budniok, Antoni; Lagiewka, Eugeniusz

    2007-01-01

    Ni + W + Si coatings were prepared by nickel deposition from a bath containing a suspension of tungsten and silicon powders. These coatings were obtained at galvanostatic conditions, at the current density of j dep = - 0.100 A cm -2 and at the temperature of 338 K. For determination of the influence of phase composition and surface morphology of these coatings on changes in the corrosion resistance, these coatings were modified in an argon atmosphere by thermal treatment at 1373 K during 1 h. A scanning electron microscope was used for surface morphology characterization of the coatings. The chemical composition of the coatings was determined by EDS and phase composition investigations were conducted by X-ray diffraction. It was found that the as-deposited coatings consist of a three-phase structure, i.e., nickel, tungsten and silicon. The phase composition for the Ni + W + Si coatings after thermal treatment is markedly different. The main peaks corresponding to Ni and W coexist with the new phases: NiW, NiWSi and a solid solution of W in Ni. Electrochemical corrosion resistance investigations were carried out in 5 M KOH, using potentiodynamic and electrochemical impedance spectroscopy (EIS) methods. On the basis of these investigations it was found that the Ni + W + Si coatings after thermal treatment are more corrosion resistant in alkaline solution than the as-deposited coatings. The reasons for this are a reduction in the amount of free nickel and tungsten, the presence of new phases (in particular polymetallic silicides), and a decrease of the active surface area of the coatings after thermal treatment

  10. Application of resistivity-based high-density prospecting to embankments with underground structure; Chika kozobutsu wo yusuru moritsuchi ni okeru hiteiko komitsudo tansa no tekiyosei

    Energy Technology Data Exchange (ETDEWEB)

    Matsui, T.; Park, G. [Osaka University, Osaka (Japan). Faculty of Engineering; Ueno, N. [Dai Nippon Construction, Gifu (Japan); Park, K. [Osaka University, Osaka (Japan)

    1997-10-22

    A structure was embedded in an embankment with homogeneous sandy soil. Resistivity was measured using three kinds of arrays, to investigate effects of the array on the underground structure. For a vertical structural model with high resistivity and a horizontal structural model with low resistivity, location of the underground structure could be grasped from the apparent resistivity profiles by individual arrays. For a transverse structural model with high resistivity, location of the underground structure could be grasped from the apparent resistivity profiles using Wenner array and pole-pole array. However, it could not be grasped from the apparent resistivity profile using dipole-dipole array. Based on the resistivity measurements for individual structural models, the dipole-dipole array was suitable for the vertical structural model, the pole-pole array was suitable for the transverse structural model, and the Wenner array was suitable for the horizontal structural model. Thus, the best apparent resistivity profiles and contrasts were obtained for individual structural models. 7 refs., 7 figs.

  11. Aminoglycoside resistance profile and structural architecture of the aminoglycoside acetyltransferase AAC(6')-Im.

    Science.gov (United States)

    Smith, Clyde A; Bhattacharya, Monolekha; Toth, Marta; Stewart, Nichole K; Vakulenko, Sergei B

    2017-11-09

    Aminoglycoside 6'-acetyltransferase-Im (AAC(6')-Im) is the closest monofunctional homolog of the AAC(6')-Ie acetyltransferase of the bifunctional enzyme AAC(6')-Ie/APH(2")-Ia. The AAC(6')-Im acetyltransferase confers 4- to 64-fold higher MICs to 4,6-disubstituted aminoglycosides and the 4,5-disubstituted aminoglycoside neomycin than AAC(6')-Ie, yet unlike AAC(6')-Ie, the AAC(6')-Im enzyme does not confer resistance to the atypical aminoglycoside fortimicin. The structure of the kanamycin A complex of AAC(6')-Im shows that the substrate binds in a shallow positively-charged pocket, with the N6' amino group positioned appropriately for an efficient nucleophilic attack on an acetyl-CoA cofactor. The AAC(6')-Ie enzyme binds kanamycin A in a sufficiently different manner to position the N6' group less efficiently, thereby reducing the activity of this enzyme towards the 4,6-disubstituted aminoglycosides. Conversely, docking studies with fortimicin in both acetyltransferases suggest that the atypical aminoglycoside might bind less productively in AAC(6')-Im, thus explaining the lack of resistance to this molecule.

  12. Wear Resistance and Mechanical Behaviour of Epoxy/Mollusk Shell Biocomposites developed for Structural Applications

    Directory of Open Access Journals (Sweden)

    I.O. Oladele

    2016-09-01

    Full Text Available Epoxy resin is one of the strongest commercially exploitable thermosetting polymers in the polymer family; however its expensive nature in comparison with other thermosetting polymers such as vinylester and polyester limits its applications as a structural material. Inexpensive fillers on the other hand, especially those derived from agro-industrial wastes are very important in reducing the overall cost of polymer composites and furthermore influential in enhancing some of their engineering properties. In the present study, the wear resistance and mechanical behaviour of epoxy polymer matrix filled with <75 and 75 μm calcined particles of African land snail shells have been comparatively investigated. The wear resistance and the mechanical behaviour of the composites were studied via Taber Abraser and INSTRON universal testing machine. Also, the elemental constituents of the calcined snail shell and the epoxy biocomposites were characterized by X-Ray Fluorescence Spectroscopy and Scanning Electron Microscopy/Energy Dispersion Spectroscopy. From the experimental results, it was observed that, at the highest filler loading, smaller particle size presented a biocomposite with significant enhancement in wear and mechanical properties. However, it was also observed that increase in particle size showed no significant enhancement in the mechanical properties of the biocomposites.

  13. Population structure of the NPGS Senegalese sorghum collection and its evaluation to identify new disease resistant genes.

    Directory of Open Access Journals (Sweden)

    Hugo E Cuevas

    Full Text Available Sorghum germplasm from West and Central Africa is cultivated in rainy and high humidity regions and is an important source of resistance genes to fungal diseases. Mold and anthracnose are two important biotic constraints to sorghum production in wet areas worldwide. Here, 158 National Plant Germplasm System (NPGS accessions from Senegal were evaluated for agronomic traits, anthracnose, and grain mold resistance at two locations, and genetically characterized according to 20 simple sequence repeat markers. A total of 221 alleles were amplified with an average of 11 alleles per locus. Each accession had a unique genetic profile (i.e., no duplicates, and the average genetic distance between accessions was 0.42. Population structure and cluster analysis separated the collection into four populations with pairwise FST values >0.15. Three of the populations were composed of Guinea-race sorghum germplasm, and one included multiple races. Anthracnose resistant accessions were present at high frequency and evenly distributed among the three Guinea-race populations. Fourteen accessions showed resistance to grain mold, and eight were resistant to both diseases. These results indicated that the NPGS of Senegal is a genetically diverse collection with a high frequency of disease resistant accessions. Nevertheless, its population structure suggests the presence of few sources of resistance to both grain mold and anthracnose, which are fixed in the germplasm. The phenotypic and genotypic information for these accessions provides a valuable resource for its correct use to broaden the genetic base of breeding programs.

  14. Population structure of the NPGS Senegalese sorghum collection and its evaluation to identify new disease resistant genes.

    Science.gov (United States)

    Cuevas, Hugo E; Prom, Louis K; Rosa-Valentin, Giseiry

    2018-01-01

    Sorghum germplasm from West and Central Africa is cultivated in rainy and high humidity regions and is an important source of resistance genes to fungal diseases. Mold and anthracnose are two important biotic constraints to sorghum production in wet areas worldwide. Here, 158 National Plant Germplasm System (NPGS) accessions from Senegal were evaluated for agronomic traits, anthracnose, and grain mold resistance at two locations, and genetically characterized according to 20 simple sequence repeat markers. A total of 221 alleles were amplified with an average of 11 alleles per locus. Each accession had a unique genetic profile (i.e., no duplicates), and the average genetic distance between accessions was 0.42. Population structure and cluster analysis separated the collection into four populations with pairwise FST values >0.15. Three of the populations were composed of Guinea-race sorghum germplasm, and one included multiple races. Anthracnose resistant accessions were present at high frequency and evenly distributed among the three Guinea-race populations. Fourteen accessions showed resistance to grain mold, and eight were resistant to both diseases. These results indicated that the NPGS of Senegal is a genetically diverse collection with a high frequency of disease resistant accessions. Nevertheless, its population structure suggests the presence of few sources of resistance to both grain mold and anthracnose, which are fixed in the germplasm. The phenotypic and genotypic information for these accessions provides a valuable resource for its correct use to broaden the genetic base of breeding programs.

  15. Specific heat, Electrical resistivity and Electronic band structure properties of noncentrosymmetric Th7Fe3superconductor.

    Science.gov (United States)

    Tran, V H; Sahakyan, M

    2017-11-17

    Noncentrosymmetric superconductor Th 7 Fe 3 has been investigated by means of specific heat, electrical resisitivity measurements and electronic properties calculations. Sudden drop in the resistivity at 2.05 ± 0.15 K and specific heat jump at 1.98 ± 0.02 K are observed, rendering the superconducting transition. A model of two BCS-type gaps appears to describe the zero-magnetic-field specific heat better than those based on the isotropic BCS theory or anisotropic functions. A positive curvature of the upper critical field H c2 (T c ) and nonlinear field dependence of the Sommerfeld coefficient at 0.4 K qualitatively support the two-gap scenario, which predicts H c2 (0) = 13 kOe. The theoretical densities of states and electronic band structures (EBS) around the Fermi energy show a mixture of Th 6d- and Fe 3d-electrons bands, being responsible for the superconductivity. Furthermore, the EBS and Fermi surfaces disclose significantly anisotropic splitting associated with asymmetric spin-orbit coupling (ASOC). The ASOC sets up also multiband structure, which presumably favours a multigap superconductivity. Electron Localization Function reveals the existence of both metallic and covalent bonds, the latter may have different strengths depending on the regions close to the Fe or Th atoms. The superconducting, electronic properties and implications of asymmetric spin-orbit coupling associated with noncentrosymmetric structure are discussed.

  16. Structure-activity relationships of diverse xanthones against multidrug resistant human tumor cells.

    Science.gov (United States)

    Wang, Qiwen; Ma, Chenyao; Ma, Yun; Li, Xiang; Chen, Yong; Chen, Jianwei

    2017-02-01

    Thirteen xanthones were isolated naturally from the stem of Securidaca inappendiculata Hassk, and structure-activity relationships (SARs) of these compounds were comparatively predicted for their cytotoxic activity against three human multidrug resistant (MDR) cell lines MCF-7/ADR, SMMC-7721/Taxol, and A549/Taxol cells. The results showed that the selected xanthones exhibited different potent cytotoxic activity against the growth of different human tumor cell lines, and most of the xanthones exhibited selective cytotoxicity against SMMC-7721/Taxol cells. Furthermore, some tested xanthones showed stronger cytotoxicity than Cisplatin, which has been used in clinical application extensively. The SARs analysis revealed that the cytotoxic activities of diverse xanthones were affected mostly by the number and position of methoxyl and hydroxyl groups. Xanthones with more free hydroxyl and methoxyl groups increased the cytotoxic activity significantly, especially for those with the presence of C-3 hydroxyl and C-4 methoxyl groups. Copyright © 2016 Elsevier Ltd. All rights reserved.

  17. Study of the structure and development of the set of reference materials of composition and structure of heat resisting nickel and intermetallic alloys

    Directory of Open Access Journals (Sweden)

    E. B. Chabina

    2016-01-01

    Full Text Available Relevance of research: There are two sizes (several microns and nanodimensional of strengthening j'-phase in single-crystal heat resisting nickel and intermetallic alloys, used for making blades of modern gas turbine engines (GTD. For in-depth study of structural and phase condition of such alloys not only qualitative description of created structure is necessary, but quantitative analysis of alloy components geometrical characteristics. Purpose of the work: Development of reference material sets of heat resisting nickel and intermetallic alloy composition and structure. Research methods: To address the measurement problem of control of structural and geometrical characteristics of single-crystal heat resisting and intermetallic alloys by analytical microscopy and X-ray diffraction analysis the research was carried out using certified measurement techniques on facilities, entered in the Register of Measurement Means of the Russian Federation. The research was carried out on microsections, foils and plates, cut in the plane {100}. Results: It is established that key parameters, defining the properties of these alloys are particle size of strengthening j' -phase, the layer thickness of j-phase between them and parameters of phases lattice. Metrological requirements for reference materials of composition and structure of heat resisting nickel and intermetallic alloys are formulated. The necessary and sufficient reference material set providing the possibility to determine the composition and structure parameters of single-crystal heat resisting nickel and intermetallic alloys is defined. The developed RM sets are certified as in-plant reference materials. Conclusion: The reference materials can be used for graduation of spectral equipment when conducting element analysis of specified class alloys; for calibration of means of measuring alloy structure parameters; for measurement of alloys phases lattice parameters; for structure reference pictures

  18. Structure of a NADH-insensitive hexameric citrate synthase that resists acid inactivation.

    Science.gov (United States)

    Francois, Julie A; Starks, Courtney M; Sivanuntakorn, Sasitorn; Jiang, Hong; Ransome, Aaron E; Nam, Jeong-Won; Constantine, Charles Z; Kappock, T Joseph

    2006-11-14

    Acetobacter aceti converts ethanol to acetic acid, and strains highly resistant to both are used to make vinegar. A. aceti survives acetic acid exposure by tolerating cytoplasmic acidification, which implies an unusual adaptation of cytoplasmic components to acidic conditions. A. aceti citrate synthase (AaCS), a hexameric type II citrate synthase, is required for acetic acid resistance and, therefore, would be expected to function at low pH. Recombinant AaCS has intrinsic acid stability that may be a consequence of strong selective pressure to function at low pH, and unexpectedly high thermal stability for a protein that has evolved to function at approximately 30 degrees C. The crystal structure of AaCS, complexed with oxaloacetate (OAA) and the inhibitor carboxymethyldethia-coenzyme A (CMX), was determined to 1.85 A resolution using protein purified by a tandem affinity purification procedure. This is the first crystal structure of a "closed" type II CS, and its active site residues interact with OAA and CMX in the same manner observed in the corresponding type I chicken CS.OAA.CMX complex. While AaCS is not regulated by NADH, it retains many of the residues used by Escherichia coli CS (EcCS) for NADH binding. The surface of AaCS is abundantly decorated with basic side chains and has many fewer uncompensated acidic charges than EcCS; this constellation of charged residues is stable in varied pH environments and may be advantageous in the A. aceti cytoplasm.

  19. Resistance and the management of complicated skin and skin structure infections: the role of ceftobiprole

    Directory of Open Access Journals (Sweden)

    April Barbour

    2010-09-01

    Full Text Available April Barbour1, Hartmut Derendorf21GlaxoSmithKline, King of Prussia, PA, USA; 2Department of Pharmaceutics, College of Pharmacy, University of Florida, Gainesville, FL, USAAbstract: Antimicrobial resistant bacteria are an increasing concern due to the resulting increase in morbidity, mortality, and health-care costs associated with the administration of inadequate or delayed antimicrobial therapy. The implications of inadequate antimicrobial therapy in complicated skin and skin structure infections (cSSSIs have gained more attention recently, most likely due to the recent emergence of community-acquired methicillin resistant Staphylococcus aureus (MRSA and the already high prevalence of MRSA in the nosocomial setting. Due to the continuous threat of resistance arising and the limitations of currently available agents for the treatment of cSSSIs, it is necessary to develop new antimicrobials for this indication. Ceftobiprole medocaril, the prodrug of ceftobiprole, is a parental investigational cephalosporin for the treatment of cSSSIs displaying a wide-spectrum of activity against both Gram-positive and Gram-negative species, including MRSA. Ceftobiprole displays noncomplex linear pharmacokinetics, is eliminated primarily by glomerular filtration, and distributes to extracellular fluid. Additionally, it has been shown that the extent of distribution to the site of action with regard to cSSSIs, ie, the extracellular space fluid of subcutaneous adipose tissue and skeletal muscle, is expected to be efficacious, as free concentrations meet efficacy targets for most pathogens. Similar to other beta-lactams, it displays an excellent safety and tolerability profile with the primary adverse events being dysgeusia in healthy volunteers, resulting from the conversion of the prodrug to the active, and nausea in patients. Ceftobiprole has demonstrated noninferiority in two large-scale pivotal studies comparing it to vancomycin, clinical cure rates 93.3% vs

  20. Structural changes and conductance thresholds in metal-free intrinsic SiOx resistive random access memory

    Science.gov (United States)

    Mehonic, Adnan; Buckwell, Mark; Montesi, Luca; Garnett, Leon; Hudziak, Stephen; Fearn, Sarah; Chater, Richard; McPhail, David; Kenyon, Anthony J.

    2015-03-01

    We present an investigation of structural changes in silicon-rich silicon oxide metal-insulator-metal resistive RAM devices. The observed unipolar switching, which is intrinsic to the bulk oxide material and does not involve movement of metal ions, correlates with changes in the structure of the oxide. We use atomic force microscopy, conductive atomic force microscopy, x-ray photoelectron spectroscopy, and secondary ion mass spectroscopy to examine the structural changes occurring as a result of switching. We confirm that protrusions formed at the surface of samples during switching are bubbles, which are likely to be related to the outdiffusion of oxygen. This supports existing models for valence-change based resistive switching in oxides. In addition, we describe parallel linear and nonlinear conduction pathways and suggest that the conductance quantum, G0, is a natural boundary between the high and low resistance states of our devices.

  1. Structural changes and conductance thresholds in metal-free intrinsic SiOx resistive random access memory

    International Nuclear Information System (INIS)

    Mehonic, Adnan; Buckwell, Mark; Montesi, Luca; Garnett, Leon; Hudziak, Stephen; Kenyon, Anthony J.; Fearn, Sarah; Chater, Richard; McPhail, David

    2015-01-01

    We present an investigation of structural changes in silicon-rich silicon oxide metal-insulator-metal resistive RAM devices. The observed unipolar switching, which is intrinsic to the bulk oxide material and does not involve movement of metal ions, correlates with changes in the structure of the oxide. We use atomic force microscopy, conductive atomic force microscopy, x-ray photoelectron spectroscopy, and secondary ion mass spectroscopy to examine the structural changes occurring as a result of switching. We confirm that protrusions formed at the surface of samples during switching are bubbles, which are likely to be related to the outdiffusion of oxygen. This supports existing models for valence-change based resistive switching in oxides. In addition, we describe parallel linear and nonlinear conduction pathways and suggest that the conductance quantum, G 0 , is a natural boundary between the high and low resistance states of our devices

  2. Structural changes and conductance thresholds in metal-free intrinsic SiO{sub x} resistive random access memory

    Energy Technology Data Exchange (ETDEWEB)

    Mehonic, Adnan, E-mail: a.mehonic@ee.ucl.ac.uk, E-mail: t.kenyon@ucl.ac.uk; Buckwell, Mark; Montesi, Luca; Garnett, Leon; Hudziak, Stephen; Kenyon, Anthony J., E-mail: a.mehonic@ee.ucl.ac.uk, E-mail: t.kenyon@ucl.ac.uk [Department of Electronic and Electrical Engineering, UCL, Torrington Place, London WC1E 7JE (United Kingdom); Fearn, Sarah; Chater, Richard; McPhail, David [Department of Materials, Imperial College London, South Kensington Campus, London SW7 2AZ (United Kingdom)

    2015-03-28

    We present an investigation of structural changes in silicon-rich silicon oxide metal-insulator-metal resistive RAM devices. The observed unipolar switching, which is intrinsic to the bulk oxide material and does not involve movement of metal ions, correlates with changes in the structure of the oxide. We use atomic force microscopy, conductive atomic force microscopy, x-ray photoelectron spectroscopy, and secondary ion mass spectroscopy to examine the structural changes occurring as a result of switching. We confirm that protrusions formed at the surface of samples during switching are bubbles, which are likely to be related to the outdiffusion of oxygen. This supports existing models for valence-change based resistive switching in oxides. In addition, we describe parallel linear and nonlinear conduction pathways and suggest that the conductance quantum, G{sub 0}, is a natural boundary between the high and low resistance states of our devices.

  3. Partial Prestress Concrete Beams Reinforced Concrete Column Joint Earthquake Resistant On Frame Structure Building

    Science.gov (United States)

    Astawa, M. D.; Kartini, W.; Lie, F. X. E.

    2018-01-01

    Floor Building that requires a large space such as for the meeting room, so it must remove the column in the middle of the room, then the span beam above the room will be long. If the beam of structural element with a span length reaches 15.00 m, then it is less effective and efficient using a regular Reinforced Concrete Beam because it requires a large section dimension, and will reduce the beauty of the view in terms of aesthetics of Architecture. In order to meet these criteria, in this design will use partial prestressing method with 400/600 mm section dimension, assuming the partial Prestressed Beam structure is still able to resist the lateral force of the earthquake. The design of the reinforcement has taken into account to resist the moment due to the gravitational load and lateral forces. The earthquake occurring on the frame structure of the building. In accordance with the provisions, the flexural moment capacity of the tendon is permitted only by 25% of the total bending moment on support of the beam, while the 75% will be charged to the reinforcing steel. Based on the analysis result, bring ini 1 (one) tendon contains 6 strand with diameter 15,2 mm. On the beam pedestal, requires 5D25 tensile reinforcement and 3D25 for the compression reinforcement, for shear reinforcement on the pedestal using Ø10-100 mm. Dimensional column section are 600/600 mm with longitudinal main reinforcement of 12D25, and transverse reinforcement Ø10-150. At the core of the beam-column joint, use the transversal reinforcement Ø10-100 mm. The moment of Column versus Beam Moment ∑Me > 1.2 Mg, with a value of 906.99 kNm > 832.25 kNm, qualify for ductility and Strong Columns-weak beam. Capacity of contribution bending moment of Strand Tendon’s is 23.95% from the total bending moment capacity of the beam, meaning in accordance with the provisions. Thus, the stability and ductility structure of Beam-Column joint is satisfy the requirements of SNI 2847: 2013 and ACI 318-11.

  4. Development of radiation resistant structural materials utilizing fission research reactors in Japan (Role of research reactors)

    International Nuclear Information System (INIS)

    Shikama, T.; Tanigawa, H.; Nozawa, T.; Muroga, T.; Aoyama, T.; Kawamura, H.; Ishihara, M.; Ito, C.; Kaneda, S.; Mimura, S.

    2009-01-01

    Structural materials for next-generation nuclear power systems should have a good radiation resistance, where the expected accumulation dose will largely exceed 10 dpa. Among several candidate materials, materials of five categories, 1. Austenitic steels, including high nickel alloys, 2. Low activation ferritic martensitic steels, 3. ODS steels (austenitic and ferritic), 4. Vanadium based alloys, 5. Silicon carbide composites (SiC/SiCf). All have been most extensively studied in Japan, in collaboration among industries, national institutes such as Japan Atomic Energy Agency (JAEA), National Institute for Fusion Science (NIFS) and National Institute for Materials Science (NIMS), and universities. The high nickel base alloys were studied for their low swelling behaviors mainly by the NIMS and the austenitic steels are studied for their reliable engineering data base and their reliable performance in irradiation environments mainly by the JAEA, mainly for their application in the near-term projects such as the ITER and the Sodium Cooled Fast Reactors. The most extensive studies are now concentrated on the Low Activation Ferritic Marsensitic steels and ODS steels, for their application in a demonstration fusion reactor and prototype sodium cooled fast reactors. Fundamental studies on radiation effects are carried out, mainly utilizing Japan Materials Testing Rector (JMTR) with its flexible irradiation ability, up to a few dpa. For higher dpa irradiation, a fast test reactor, JOYO is utilized up to several 10s dpa. Some international collaborations such as Japan/USA and Japan/France are effective to utilize reactors abroad, such as High Flux Isotope Reactor (HFIR) of Oak Ridge National Laboratory, and sodium cooled high flux fast reactors in France. Silicon carbide based composites are extensively studied by university groups led by Kyoto University and the JAEA. For their performance in heavy irradiation environments, the Japan/USA collaboration plays an important role

  5. Molecular analysis of the HIV-1 resistance development: Enzymatic activities, crystal structures, and thermodynamics of nelfinavir-resistant HIV protease mutants

    Czech Academy of Sciences Publication Activity Database

    Kožíšek, Milan; Bray, J.; Řezáčová, Pavlína; Šašková, Klára; Brynda, Jiří; Pokorná, Jana; Mammano, F.; Rulíšek, Lubomír; Konvalinka, Jan

    2007-01-01

    Roč. 374, č. 4 (2007), s. 1005-1016 ISSN 0022-2836 R&D Projects: GA MŠk 1M0508; GA MŠk LC512; GA MZd NR8571 Institutional research plan: CEZ:AV0Z40550506; CEZ:AV0Z50520514 Keywords : HIV protease inhibitors * protease-inhibitor structure * isothermal calorimetry * antiviral resistance development Subject RIV: CE - Biochemistry Impact factor: 4.472, year: 2007

  6. Determinants of impaired quality of life in patients with fibrous dysplasia.

    Science.gov (United States)

    Majoor, Bas C J; Andela, Cornelie D; Bruggemann, Jens; van de Sande, Michiel A J; Kaptein, Ad A; Hamdy, Neveen A T; Dijkstra, P D Sander; Appelman-Dijkstra, Natasha M

    2017-04-27

    Fibrous dysplasia is a rare bone disorder, commonly associated with pain, deformity and fractures, which may significantly impact on quality of life. In this study we evaluate quality of life in patients with fibrous dysplasia using the Short Form-36 and the Brief Pain Inventory questionnaires. Data were compared with those of the general Dutch population. Out of 138 patients from a cohort of 255 patients with fibrous dysplasia that were sent questionnaires assessing quality of life and pain, the response rate was 70.3%, with 97 patients, predominantly female (65%), completing the questionnaires. Monostotic fibrous dysplasia was predominant (n = 62, 64%). Fibrous dysplasia patients had significantly lower quality of life outcome scores than the general Dutch population for all tested domains of the Short Form-36 except for the "Mental health" and the "Role emotional" domains. More severe forms of fibrous dysplasia, had the more severe Short-Form-36 quality of life outcomes, but there was no significant difference in Brief Pain Inventory domains between different subtypes of fibrous dysplasia. Quality of life was lower in patients with higher disease burden, as reflected by high skeletal burden scores (p = 0.003) and high levels of P1NP (p = 0.002). We demonstrate impairments in all domains of quality of life, except for 'Mental health' and 'Role emotional' domains, across the wide spectrum of fibrous dysplasia including its milder forms. We identified high skeletal burden scores, reflecting disease severity, as the most consistent predictor of impaired quality of life. Our findings hold significant clinical implications as they draw attention to the clinically unmet need to address quality of life issues in the management of patients with all subtypes of fibrous dysplasia, including its milder forms.

  7. Structure and Function of APH(4)-Ia, a Hygromycin B Resistance Enzyme

    Energy Technology Data Exchange (ETDEWEB)

    Stogios, Peter J.; Shakya, Tushar; Evdokimova, Elena; Savchenko, Alexei; Wright, Gerard D. (Toronto); (McMaster U.)

    2011-11-18

    The aminoglycoside phosphotransferase (APH) APH(4)-Ia is one of two enzymes responsible for bacterial resistance to the atypical aminoglycoside antibiotic hygromycin B (hygB). The crystal structure of APH(4)-Ia enzyme was solved in complex with hygB at 1.95 {angstrom} resolution. The APH(4)-Ia structure adapts a general two-lobe architecture shared by other APH enzymes and eukaryotic kinases, with the active site located at the interdomain cavity. The enzyme forms an extended hydrogen bond network with hygB primarily through polar and acidic side chain groups. Individual alanine substitutions of seven residues involved in hygB binding did not have significant effect on APH(4)-Ia enzymatic activity, indicating that the binding affinity is spread across a distributed network. hygB appeared as the only substrate recognized by APH(4)-Ia among the panel of 14 aminoglycoside compounds. Analysis of the active site architecture and the interaction with the hygB molecule demonstrated several unique features supporting such restricted substrate specificity. Primarily the APH(4)-Ia substrate-binding site contains a cluster of hydrophobic residues that provides a complementary surface to the twisted structure of the substrate. Similar to APH(2{double_prime}) enzymes, the APH(4)-Ia is able to utilize either ATP or GTP for phosphoryl transfer. The defined structural features of APH(4)-Ia interactions with hygB and the promiscuity in regard to ATP or GTP binding could be exploited for the design of novel aminoglycoside antibiotics or inhibitors of this enzyme.

  8. Fibrous Myopathy as a Complication of Repeated Intramuscular Injections for Chronic Headache

    Directory of Open Access Journals (Sweden)

    R Burnham

    2006-01-01

    Full Text Available Two cases of fibrous myopathy associated with repeated, long-term intramuscular injections for treatment of chronic temporomandibular joint pain and chronic headache, respectively, are described. Both patients developed severe, function-limiting contractures in upper and lower extremity muscles used as injection sites. In one of the cases, the contractures were painful. Electrophysiological testing, magnetic resonance imaging and muscle biopsy results were all consistent with myopathy and replacement of skeletal muscle with noncontractile fibrous tissue. These cases are presented to increase awareness of fibrous myopathy and to promote surveillance for this serious potential complication of long-term intramuscular injections in chronic headache and other pain patients.

  9. Comparison of MRA source image and IVUS for evaluating fibrous cap of carotid plaque

    International Nuclear Information System (INIS)

    Sakamoto, Masahiko; Taoka, Toshiaki; Nakagawa, Hiroyuki; Myochin, Kaoru; Yoshikawa, Kimihiko; Takayama, Katsutoshi; Wada, Takeshi; Iwasaki, Satoru; Fukuzumi, Akio

    2007-01-01

    The purpose is evaluating the usefulness of three-dimensional (3D) time of flight (TOF) MR angiography (MRA) source image for investigating fibrous cap of carotid plaque. The percentage of fibrous cap defect of 17 carotid stenotic lesions was calculated on both MRA source images and intravascular ultrasound (IVUS) images. Five lesions were correlated, but 9 had slight gap (10-20%) and 3 had moderate gap (30-40%). There was significant correlation (P<;0.01, r=0.721) by the Pearson's correlation coefficient. MRA source image can evaluate fibrous cap of carotid plaque. (author)

  10. A large infiltrating fibrous hamartoma of infancy in the abdominal wall with rare associated tuberous sclerosis

    Energy Technology Data Exchange (ETDEWEB)

    Han, Hye-Jeong; Lim, Gye-Yeon [The Catholic University of Korea, Department of Radiology, St. Mary' s Hospital, Seoul (Korea); You, Chang-Young [The Catholic University of Korea, Department of Pathology, St. Mary' s Hospital, Seoul (Korea)

    2009-07-15

    Tuberous sclerosis is a complex autosomal-dominant neurocutaneous syndrome characterized by hamartomatous malformations of fibrous and connective tissues in various organs. Although various histologic types of soft-tissue masses can occur with tuberous sclerosis, we present a unique case of fibrous hamartoma of infancy presenting as large infiltrating cutaneous and subcutaneous masses in the abdominal wall in a 4-year-old boy with tuberous sclerosis. Although the co-occurrence of tuberous sclerosis and fibrous hamartoma of infancy is very rare, it should be considered in the differential diagnosis of subcutaneous soft-tissue masses found in children with tuberous sclerosis. (orig.)

  11. Congenital costo-vertebral fibrous band and congenital kyphoscoliosis: a previously unreported combination.

    Science.gov (United States)

    Eid, Tony; Ghostine, Bachir; Kreichaty, Gaby; Daher, Paul; Ghanem, Ismat

    2013-05-01

    Congenital kyphoscoliosis (CKS) results from abnormal vertebral chondrification. Congenital fibrous bands occur in several locations with variable impact on vertebral development. We report a previously unreported case of a female infant with CKS presenting with an L2 hypoplastic vertebra and a costo-vertebral fibrous band extending to the skin in the form of a dimple. We also describe the therapeutic approach, consisting of surgical excision of the fibrous band and postoperative fulltime bracing, with a 7-year follow-up. We recommend a high index of suspicion in any unusual presentation of CKS and insist on case by case management in such cases.

  12. Effect of Thermal Fields on the Structure of Corrosion-Resistant Steels Under Different Modes of Laser Treatment

    Science.gov (United States)

    Tarasova, T. V.; Gusarov, A. V.; Protasov, K. E.; Filatova, A. A.

    2017-11-01

    The influence of temperature fields on the structure and properties of corrosion-resistant chromium steels under different modes of laser treatment is investigated. A model of heat transfer under laser impact on target is used to plot thermal fields and cycles and cooling rates. It is shown that the model used for computing thermal fields gives tentative geometric sizes of the fusion zones under laser treatment and selective laser fusion. The cooling rate is shown to have decisive influence on the structure of corrosion-resistant steels after laser treatment with surface fusion in devices for pulsed, continuous, and selective laser melting.

  13. Preparation and characterization of NaOH treated micro-fibrous polyethylene terephthalate nonwovens for biomedical application.

    Science.gov (United States)

    Hadjizadeh, Afra; Ajji, Abdellah; Bureau, Martin N

    2010-11-01

    Recently, micro-fibrous polyethylene terephthalate nonwovens have been investigated and applied in many biotechnological and biomedical applications. NaOH treatment has been used as a simple and cost effective method to alter surface properties, in order to overcome their surface inertness. However, the effects of this treatment on the matrices mechanical and physical properties; particularly, those composed of fibers with small diameter (<20 microm); have been poorly investigated. This study investigates the variations, imposed by the NaOH treatment, in the physical and tensile properties of micro-fibrous polyethylene terephthalate mats. Polyethylene terephthalate webs with two different average fiber diameters of 6+/-2.5 and 10+/-4 microm were produced by melt blowing process. A number of these webs were consolidated to prepare fibrous matrices using a thermal treatment. The matrices were treated using NaOH 1 N at 65 degrees C for various durations (ranging from 20 min to 24 h). In addition to their physical properties such as weight loss, thickness, porosity, shrinkage and surface density; their morphology and tensile properties were also evaluated using scanning electron microscopy and micromechanical tester, respectively. In general, by increasing treatment duration, weight loss, porosity, and shrinkage increased, while thickness and density decreased. As a result of treatment duration, pores appeared on the surface of individual fibers, and tensile stress and Young's modulus decreased while tensile strain increased. Mats with different fiber diameters showed different physical and mechanical properties. These findings suggested that the structure of the matrices and the properties required for its end use, for biomedical applications including scaffolding materials for tissue engineering, should be considered in selecting NaOH treatment condition. (c) 2010. Published by Elsevier Ltd.

  14. Optical and electrochemical studies of polyaniline/SnO{sub 2} fibrous nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Manivel, P. [Department of Nanoscience and Technology, Bharathiar University, Coimbatore 641 046, Tamil Nadu (India); Ramakrishnan, S.; Kothurkar, Nikhil K. [Department of Chemical Engineering and Material Science, Amrita Vishwa Vidyapeetham, Coimbatore 641 112, Tamil Nadu (India); Balamurugan, A.; Ponpandian, N.; Mangalaraj, D. [Department of Nanoscience and Technology, Bharathiar University, Coimbatore 641 046, Tamil Nadu (India); Viswanathan, C., E-mail: viswanathan@buc.edu.in [Department of Nanoscience and Technology, Bharathiar University, Coimbatore 641 046, Tamil Nadu (India)

    2013-02-15

    Graphical abstract: Fiber with porous like structure of PANI/SnO{sub 2} nanocomposites were prepared by simplest in situ chemical polymerization method. The PL emission spectra revealed that the band from 404 and 436 nm which is related with oxygen vacancies. The excellent electrochemical properties of composite electrode show the specific capacitance of 173 F/g at a scan rate of 25 m V/s. Display Omitted Highlights: ► Self assembled PANI/SnO{sub 2} nanocomposites were synthesized by simple polymerization method. ► Electrochemical behavior of PANI/SnO{sub 2} nanocomposites electrode was analyzed by CV. ► Nanocomposites exhibit a higher specific capacitance of 173 F/g, compared with pure SnO{sub 2}. -- Abstract: Polyaniline (PANI)/tin oxide (SnO{sub 2}) fibrous nanocomposites were successfully prepared by an in situ chemical polymerization method with suitable conditions. The obtained composites were characterized by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy, photoluminescence (PL), electrical conductivity and cyclic voltammetry studies (CV). The XRD pattern of the as-prepared sample shows the presence of tetragonal SnO{sub 2} and the crystalline structure of SnO{sub 2} was not affected with the incorporation of PANI. The FTIR analysis confirms the uniform attachment of PANI on the surface of SnO{sub 2} nanostructures. SEM images show a fibrous agglomerated structure of PANI/SnO{sub 2}. The PL emission spectra revealed that the band from 404 and 436 nm which is related with oxygen vacancies. The electrochemical behavior of the PANI/SnO{sub 2} composite electrode was evaluated in a H{sub 2}SO{sub 4} solution using cyclic voltammetry. The composite electrode exhibited a specific capacitance of 173 F/g at a scan rate 25 mV/s. Thus the as-prepared PANI/SnO{sub 2} composite shows excellent electrochemical properties, suggesting that this composite is a promising material for supercapacitors.

  15. Fibrous-Root-Inspired Design and Lithium Storage Applications of a Co-Zn Binary Synergistic Nanoarray System.

    Science.gov (United States)

    Yu, Jia; Chen, Shimou; Hao, Wenjun; Zhang, Suojiang

    2016-02-23

    Developing lithium ion batteries (LIBs) with fast charging/discharging capability and high capacity is a significant issue for future technical requirements. Transition-metal oxide (TMO) materials are widely studied as the next-generation LIB anode to satisfy this requirement due to their specific capacity, nearly three times than that of conventional graphite anode, and low cost. Meanwhile, they also suffer from slow lithium diffusion and limited electrochemical and structural stability, especially at high charging/discharging rate. The structure design of TMO is an effective strategy to obtain desirable LIB performance. Herein, inspired by natural fibrous roots consisting of functional and supporting units that can enhance substances and energy exchange efficiently, fibrous-root-like Zn(x)Co(3-x)O4@Zn(1-y)Co(y)O binary TMO nanoarrays are designed and synthesized on Cu substrates through a facile one-pot, successive-deposition process for use as an integrated LIB anode. In a multilevel array ordered by orientation, ultrafine Zn(x)Co(3-x)O4 nanowire functional units and stable Zn(1-y)Co(y)O nanorod supporting units synergize, resulting in superior rate performance. At a high current density of 500 mAg(-1), they could maintain a discharge capacity as high as 804 mAh g(-1) after 100 cycles, working much higher than unary cobalt-based and zinc-based nanoarrays. This binary synergistic nanoarray system identifies an optimized electrode design strategy for advanced battery materials.

  16. Bacterial community structure and abundances of antibiotic resistance genes in heavy metals contaminated agricultural soil.

    Science.gov (United States)

    Zhang, Fengli; Zhao, Xiaoxue; Li, Qingbo; Liu, Jia; Ding, Jizhe; Wu, Huiying; Zhao, Zongsheng; Ba, Yue; Cheng, Xuemin; Cui, Liuxin; Li, Hongping; Zhu, Jingyuan

    2018-01-22

    Soil contamination with heavy metals is a worldwide problem especially in China. The interrelation of soil bacterial community structure, antibiotic resistance genes, and heavy metal contamination in soil is still unclear. Here, seven agricultural areas (G1-G7) with heavy metal contamination were sampled with different distances (741 to 2556 m) to the factory. Denaturing gradient gel electrophoresis (DGGE) and Shannon index were used to analyze bacterial community diversity. Real-time fluorescence quantitative PCR was used to detect the relative abundance of ARGs sul1, sul2, tetA, tetM, tetW, one mobile genetic elements (MGE) inti1. Results showed that all samples were polluted by Cadmium (Cd), and some of them were polluted by lead (Pb), mercury (Hg), arsenic (As), copper (Cu), and zinc (Zn). DGGE showed that the most abundant bacterial species were found in G7 with the lightest heavy metal contamination. The results of the principal component analysis and clustering analysis both showed that G7 could not be classified with other samples. The relative abundance of sul1 was correlated with Cu, Zn concentration. Gene sul2 are positively related with total phosphorus, and tetM was associated with organic matter. Total gene abundances and relative abundance of inti1 both correlated with organic matter. Redundancy analysis showed that Zn and sul2 were significantly related with bacterial community structure. Together, our results indicate a complex linkage between soil heavy metal concentration, bacterial community composition, and some global disseminated ARG abundance.

  17. Nanoscale fluid-structure interaction: flow resistance and energy transfer between water and carbon nanotubes.

    Science.gov (United States)

    Chen, Chao; Ma, Ming; Jin, Kai; Liu, Jefferson Zhe; Shen, Luming; Zheng, Quanshui; Xu, Zhiping

    2011-10-01

    We investigate here water flow passing a single-walled carbon nanotube (CNT), through analysis based on combined atomistic and continuum mechanics simulations. The relation between drag coefficient C(D) and Reynolds number Re is obtained for a wide range of flow speed u from 5 to 600 m/s. The results suggest that Stokes law for creep flow works well for small Reynolds numbers up to 0.1 (u ≈ 100 m/s), and indicates a linear dependence between drag force and flow velocity. Significant deviation is observed at elevated Re values, which is discussed by considering the interfacial slippage, reduction of viscosity due to friction-induced local heating, and flow-induced structural vibration. We find that interfacial slippage has a limited contribution to the reduction of the resistance, and excitations of low-frequency vibration modes in the carbon nanotube play an important role in energy transfer between water and carbon nanotubes, especially at high flow speeds where drastic enhancement of the carbon nanotube vibration is observed. The results reported here reveal nanoscale fluid-structure interacting mechanisms, and lay the ground for rational design of nanofluidics and nanoelectromechanical devices operating in a fluidic environment.

  18. Characterization of oligomeric xylan structures from corn fiber resistant to pretreatment and simultaneous saccharification and fermentation.

    Science.gov (United States)

    Appeldoorn, Maaike M; Kabel, Mirjam A; Van Eylen, David; Gruppen, Harry; Schols, Henk A

    2010-11-10

    Corn fiber, a byproduct from the corn industry, would be a good source for bioethanol production if the hemicellulose, consisting of polymeric glucoronoarabinoxylans, can be degraded into fermentable sugars. Structural knowledge of the hemicellulose is needed to improve the enzymatic hydrolyses of corn fiber. Oligosaccharides that resisted a mild acid pretreatment and subsequent enzymatic hydrolysis, representing 50% of the starting material, were fractionated on reversed phase and size exclusion material and characterized. The oligosaccharides within each fraction were highly substituted by various compounds. Oligosaccharides containing uronic acid were accumulated in two polar fractions unless also a feruloyl group was present. Feruloylated oligosaccharides, containing mono- and/or diferulic acid, were accumulated within four more apolar fractions. All fractions contained high amounts of acetyl substituents. The data show that complex xylan oligomers are present in which ferulic acid, diferulates, acetic acid, galactose, arabinose, and uronic acids were combined within an oligomer. Hypothetical structures are discussed, demonstrating which enzyme activities are lacking to fully degrade corn glucuronoarabinoxylans.

  19. Three-dimensional resistivity structure of Furnas volcano (Azores archipelago, Portugal) revealed by magnetotelluric data

    Science.gov (United States)

    Kiyan, Duygu; Hogg, Colin; Rath, Volker; Byrdina, Svetlana; Vandemeulebrouck, Jean; Revil, Andre; Silva, Catarina; Viveiros, Fatima; Ferreira, Teresa; Carmo, Rita

    2017-04-01

    The Furnas volcano is the eastern-most of the three active central volcanoes of Sao Miguel Island. The main caldera formed about 30 ka BP, followed by a younger eruption at 10-12 ka BP, which is responsible for the steep topography of more than 200 m in the target area. It contains several very young eruptive centers, and a shallow caldera lake. Tectonic features of varying directions have been identified in the caldera and its vicinity (Carmo et al., 2015). In the northern part of the caldera, containing the fumarole field of Caldeiras das Furnas, a detailed map of surface CO2 emissions was recently made available (Viveiros et al., 2010). Following a pilot survey of 13 AudioMagnetoTelluric soundings (AMT) and Electrical Resistivity Tomography (ERT) data collected along two profiles in the eastern part of Furnas caldera in 2015, a second campaign was completed in June 2016, yielding a total of 39 separate soundings including 15 broad-band magnetotelluric (MT) soundings to image the electrical conductivity of the subsurface. The data quality achieved by both techniques is very good, and initial results indicate a general correlation between regions of elevated conductivity at depth and the mapped surface CO2 emissions, suggesting that they may both be caused by the presence hydrothermal fluids. Dimensionality and directionality analysis using the WALDIM (Marti et al., 2009) approach in conjunction with Phase Tensor (Caldwell et al., 2004) indicate that the geo-electrical structure needs to be inverted in 3-D. Indicators of directionality derived from the analysis follow the general geological, fault dominated structural trend of NE-SW of Sao Miguel Island. A quantitative analysis of the potential influence of the Atlantic Ocean indicates that MT data up to 1 second period can be used in inversions with confidence without including the ocean. The 3-D inversions thus have been performed including only high-resolution topography and the Furnas lake bathymetry data

  20. Influence of structural relaxation and partial devitrification on the corrosion resistance of Fe78B13Si9 amorphous alloy

    International Nuclear Information System (INIS)

    Souza, C.A.C.; Politi, F.S.; Kiminami, C.S.

    1998-01-01

    Amorphous alloys obtained by rapid solidification from the melt exhibit a similar structure to those observed in the liquid state, i.e., without long range ordering, in such a way that the constituents of the alloy usually are randomly and homogeneously distributed. Amorphous alloys, depending on their composition, may exhibit interesting characteristics such as very soft magnetic properties and improved resistance to corrosion. The high corrosion resistance of these alloys is attributed mainly to a higher rate of dissolution of passivating elements in the amorphous state. In addition, amorphous alloys are chemically homogeneous and free of defects such as grain boundaries, precipitates and segregation, which are favorable sites for corrosion. The corrosion resistance of amorphous alloys also depends on their thermal history. Several authors have reported that structural changes, such as structural relaxation and devitrification caused by annealing, change significantly the corrosion properties of these alloys. The purpose of this paper is to study corrosion resistance of the amorphous FeBSi alloy and the effects of structural changes such as structural relaxation and partial crystallization caused by annealing