Sample records for solid host matrix

  1. CH{sub 3} spin probe in solid Kr: Matrix structure and guest–host interaction

    Dmitriev, Yu.A., E-mail: [Ioffe Institute, 26 Politekhnicheskaya ul., 194021 St. Petersburg (Russian Federation); Melnikov, V.D. [Ioffe Institute, 26 Politekhnicheskaya ul., 194021 St. Petersburg (Russian Federation); Styrov, K.G. [Institute of Computing and Control, St. Petersburg State Polytechnical University, 29 Politekhnicheskaya ul., 195251 St. Petersburg (Russian Federation); Benetis, N.P. [Department of Pollution Control, Technological Education Institution, TEI, West Macedonia, Kozani 501 00 (Greece)


    Experimental EPR data obtained for the methyl, CH{sub 3}, radical trapped in quench condensed solid Kr are analyzed rendering the radical a probe for determination of regional disorder in Kr and similar solid matrices. Formation of regions of a highly disordered local matrix structure is proved. An attempt is presented of assessing a disorder parameter, based on the line broadening. The new structure is shown to be very effective in accumulating the radicals which are transiently mobile at the Kr 4.2 K surface. We discuss a model of the trapped radical rotation, which includes somewhat different mechanism than the hindrance of the rotation about the C{sub 3} axis and the rotation about the in-plane C{sub 2} axes. The level of the thermal contact of the radical spin-rotation motion with the lattice degrees of freedom in regions of varying order in the Kr solid matrix was assessed by progressive saturation curve-fitting parameters related to the spin-lattice relaxation time T{sub 1} of the radical.

  2. Solid-matrix luminescence analysis

    Hurtubise, R.J.


    Several interactions with lumiphors adsorbed on filter paper were elucidated from experiments with moisture, modulus and heavy-atom salts. The data were interpreted using static and dynamic quenching models, heavy-atom theory, and a theory related to the modulus of paper. With cyclodextrin-salt matrices, it was shown that 10% [alpha]-cyclodextrin/NaCl was very effective for obtaining strong room-temperature fluorescence and moderate room-temperature phosphorescence from adsorbed stereoisomeric tetrols. Extensive photophysical information was obtained for the four tetrols on 10% [alpha]-cyclodextrin/NaCl. The photophysical information acquired was used to develop a method for characterizing two of the tetrols. Work with model compounds adsorbed on deuterated sodium acetate showed that C-H vibrations in the undeuterated sodium acetate were not responsible for the deactivation of the excited triplet state in the model phosphors investigated. A considerable amount of solution luminescence and solid-matrix luminescence data were compared. The most important finding was that in several cases the room-temperature solid-matrix luminescence quantum yields were greater than the solution low-temperature quantum yield values.

  3. Synthesis of Ge nanocrystals embedded in a Si host matrix

    Ngiam, Shih-Tung; Jensen, Klavs F.; Kolenbrander, K. D.


    The synthesis of a composite material consisting of Ge nanoclusters (greater than or equal to 2 nm in diameter) embedded in a Si host matrix is reported. The Ge nanoparticles are produced by pulsed laser ablation and are codeposited in a Si film simultaneously grown by chemical beam epitaxy using disilane. Scanning transmission electron microscopy, combined with energy-dispersive x-ray measurements, show that discrete Ge particles (greater than or equal to 2 nm diameter) are deposited within a polycrystalline Si host matrix. High-resolution transmission electron microscopy reveals that the paricles are crystalline with a lattice spacing corresponding to that of Ge. The enhancement of Si deposition rates from silanes in the presence of Ge, previously demonstrated in chemical vapor deposition of Si(1 - x)Ge(x) alloys, is shown to facilitate the growth of a Si layer around the Ge nanocrystals. The overall composition of the Ge cluster/Si host composite material is determined by Rutherford backscattering measurements.

  4. Dentin matrix degradation by host Matrix Metalloproteinases: inhibition and clinical perspectives towards regeneration.

    Catherine eChaussain


    Full Text Available Bacterial enzymes have long been considered solely accountable for the degradation of the dentin matrix during the carious process. However, the emerging literature suggests that host-derived enzymes, and in particular the matrix metalloproteinases (MMPs contained in dentin and saliva can play a major role in this process by their ability to degrade the dentin matrix from within. These findings are important since they open new therapeutic options for caries prevention and treatment. The possibility of using MMP inhibitors to interfere with dentin caries progression is discussed. Furthermore, the potential release of bioactive peptides by the enzymatic cleavage of dentin matrix proteins by MMPs during the carious process is discussed. These peptides, once identified, may constitute promising therapeutical tools for tooth and bone regeneration.

  5. The Role of Host-derived Dentinal Matrix Metalloproteinases in Reducing Dentin Bonding of Resin Adhesives

    Zhang, Shan-chuan; Kern, Matthias


    Dentin matrix metalloproteinases (MMPs) are a family of host-derived proteolytic enzymes trapped within mineralized dentin matrix, which have the ability to hydrolyze the organic matrix of demineralized dentin. After bonding with resins to dentin there are usually some exposed collagen fibrils at the bottom of the hybrid layer owing to imperfect resin impregnation of the demineralized dentin matrix. Exposed collagen fibrils might be affected by MMPs inducing hydrolytic degradation, which migh...

  6. Dichromatic laser photolysis of eosin in solid gelatinous matrix

    Sizykh, A. G.; Slyusareva, E. A.


    The laser irradiation of the thin films of solid solution of eosin in gelatinous matrix in the first and some upper dyes absorption bands leads to decrease of films optical density due to reaction of photoreduction. In the paper the kinetic of photoreduction of the dye eosin K in polymeric matrix in three cases of irradiation was experimentally investigated: a) irradiation by N2 laser (λ=337nm, second band of absorption, π=2 nsec, repetition rate-100 Hz, average power-2,2 mW), b) irradiation by Ar-laser (λ=488 nm, first band of absorption, 6,5-12 mW), c) under a simultaneous action of both Ar and N2-lasers. It was demonstrated that the most effective reaction of photoreduction took place in case of direct populating of upper singlet states with probable following nonradiative transition into equienergetic triplet states (energy ranges 35000-45000 sm-1).

  7. Thermal transport investigation in a CNTs/solid matrix composite

    Boulerouah, Aoumeur; Longuemart, Stéphane; Hus, Philippe; Sahraoui, Abdelhak Hadj


    The evolution of the thermal parameters of solid-solid composites based on carbon nanotubes (CNTs) (single-walled (SWNT) and multi-walled (MWNT)) were studied. A granular potassium bromide (KBr) material was chosen as a matrix. The evolutions of the dynamic thermal parameters (diffusivity, effusivity and conductivity) of the composites as a function of the weight fraction of the CNTs inclusions were obtained using the photoacoustic technique. The experimental evolution of the thermal conductivity of the composites with the CNTs loading showed two distinct behaviours, an increase up to around 2% of CNTs loading followed by a decrease. A heat transport model has been proposed to account for these two different observed trends providing a consistent explanation of the experimental data.

  8. Thermalization of a two-dimensional photon gas in a polymeric host matrix

    Schmitt, Julian; Damm, Tobias; Vewinger, Frank; Weitz, Martin; Klaers, Jan


    We investigate thermodynamic properties of a two-dimensional photon gas confined by a dye-filled optical microcavity. A thermally equilibrated state of the photon gas is achieved by radiative coupling to a heat bath that is realized with dye molecules embedded in a polymer at room temperature. The chemical potential of the gas is freely adjustable. The optical microcavity consisting of two curved mirrors induces both a non-vanishing effective photon mass and a harmonic trapping potential for the photons. While previous experiments of our group have used liquid dye solutions, the measurements described here are based on dye molecules incorporated into a polymer host matrix. The solid state material allows a simplified operation of the experimental scheme. We furthermore describe studies of fluorescence properties of dye-doped polymers, and verify the applicability of Kennard-Stepanov theory in this system. In the future, dye-based solid state systems hold promise for the realization of single-mode light sources in thermal equilibrium based on Bose-Einstein condensation of photons, as well as for solar energy concentrators.

  9. Solid lipid excipients - matrix agents for sustained drug delivery.

    Rosiaux, Yvonne; Jannin, Vincent; Hughes, Sophie; Marchaud, Delphine


    Lipid excipients are attracting interest from drug developers due to their performance, ease of use, versatility and their potential to generate intellectual property through innovation in drug delivery particularly in the case of modifying drug release systems. Many articles have described the use of lipid excipients to develop matrix modified release dosage forms in a range of processing techniques, therefore a comprehensive review is timely to collect together and analyze key information. This review article focuses on the utility of lipid excipients in solid sustained drug delivery systems with emphasis on the efficiency and robustness of these systems with respect to: (i) the choice of the manufacturing process and impact on drug release, (ii) the fundamental drug release mechanisms, (iii) resistance of the drug formulation under physiological conditions and (iv) long-term stability. Understanding the functionality of these versatile excipients in formulation is elementary for the development of highly robust lipid-based sustained release medicines.

  10. Determining the solid phases hosting arsenic in Mekong Delta sediments

    Wucher, M.; Stuckey, J. W.; McCurdy, S.; Fendorf, S.


    The major river systems originating from the Himalaya deposit arsenic bearing sediment into the deltas of South and Southeast Asia. High rates of sediment and organic carbon deposition combined with frequent flooding leads to anaerobic processes that release arsenic into the pore-water. Arsenic concentrations in the groundwater of these sedimentary basins are often above the World Health Organization drinking water standard of 10 μg As L-1. As a result, 150 million people are at risk of chronic arsenic poisoning through water and rice consumption. The composition of the iron bearing phases hosting the arsenic in these deltaic sediments is poorly understood. Here we implemented a suite of selective chemical extractions to help constrain the types of arsenic bearing solid phases, which were complimented with synchrotron-based X-ray absorption spectroscopy and X-ray diffraction analyses to define the arsenic and iron mineralogy of the system. Sediment cores were collected in triplicate from a seasonally-inundated wetland in Cambodia at depths of 10, 50, 100, and 150 centimeters. We hypothesize that (i) arsenic will be predominantly associated with iron oxides, and (ii) the ratio of crystalline to amorphous iron oxides will increase with sediment depth (and age). We performed four selective extractions in parallel to quantify the various pools of arsenic. First, 1 M MgCl2 was used to extract electrostatically-bound arsenic (labile forms) from the sediment. Second, 1 M NaH2PO4 targeted strongly adsorbed arsenic. Third, 1 M HCl was used to liberated arsenic coprecipitated with amorphous Fe/Mn oxides, carbonates, and acid-volatile sulfides. Finally, a dithionite extraction was used to account for arsenic associated with reducible Fe/Mn oxides. Through this work, we identified the composition of the phases hosting arsenic at various depths through the soil profile, improving our understanding of how arsenic persists in the aquifer. In addition, defining the arsenic and

  11. Bottom-up and top-down solid-state NMR approaches for bacterial biofilm matrix composition

    Cegelski, Lynette


    The genomics and proteomics revolutions have been enormously successful in providing crucial "parts lists" for biological systems. Yet, formidable challenges exist in generating complete descriptions of how the parts function and assemble into macromolecular complexes and whole-cell assemblies. Bacterial biofilms are complex multicellular bacterial communities protected by a slime-like extracellular matrix that confers protection to environmental stress and enhances resistance to antibiotics and host defenses. As a non-crystalline, insoluble, heterogeneous assembly, the biofilm extracellular matrix poses a challenge to compositional analysis by conventional methods. In this perspective, bottom-up and top-down solid-state NMR approaches are described for defining chemical composition in complex macrosystems. The "sum-of-the-parts" bottom-up approach was introduced to examine the amyloid-integrated biofilms formed by Escherichia coli and permitted the first determination of the composition of the intact extracellular matrix from a bacterial biofilm. An alternative top-down approach was developed to define composition in Vibrio cholerae biofilms and relied on an extensive panel of NMR measurements to tease out specific carbon pools from a single sample of the intact extracellular matrix. These two approaches are widely applicable to other heterogeneous assemblies. For bacterial biofilms, quantitative parameters of matrix composition are needed to understand how biofilms are assembled, to improve the development of biofilm inhibitors, and to dissect inhibitor modes of action. Solid-state NMR approaches will also be invaluable in obtaining parameters of matrix architecture.

  12. The role of host-derived dentinal matrix metalloproteinases in reducing dentin bonding of resin adhesives.

    Zhang, Shan-chuan; Kern, Matthias


    Dentin matrix metalloproteinases (MMPs) are a family of host-derived proteolytic enzymes trapped within mineralized dentin matrix, which have the ability to hydrolyze the organic matrix of demineralized dentin. After bonding with resins to dentin there are usually some exposed collagen fibrils at the bottom of the hybrid layer owing to imperfect resin impregnation of the demineralized dentin matrix. Exposed collagen fibrils might be affected by MMPs inducing hydrolytic degradation, which might result in reduced bond strength. Most MMPs are synthesized and released from odontoblasts in the form of proenzymes, requiring activation to degrade extracellular matrix components. Unfortunately, they can be activated by modem self-etch and etch-and-rinse adhesives. The aim of this review is to summarize the current knowledge of the role of dentinal host-derived MMPs in dentin matrix degradation. We also discuss various available MMP inhibitors, especially chlorhexidine, and suggest that they could provide a potential pathway for inhibiting collagen degradation in bonding interfaces thereby increasing dentin bonding durability.

  13. Thermophysical processes initiated by inert-matrix-hosted nanoparticles heated by laser pulses of different durations

    Kalenskii, A. V.; Zvekov, A. A.; Nikitin, A. P.; Aduev, B. P.


    In the present study, a model for the heating of inert-matrix-hosted metal nanoparticles with laser radiation taking into account the melting processes is examined. The calculations were performed using the characteristics of gold and pentaerythritol tetranitrate materials. The kinetic dependences of the temperature and molten-layer thickness on nanoparticle surface were calculated. The main non-dimensional governing parameters of the model were identified. An expression for the maximum thickness of molten layer was obtained. The results can be used in predicting the stability of nonlinear-optics devices with hosted gold nanoparticles, in raising the efficiency of hyperthermia cancer therapy, and in optimizing the optical detonators.

  14. Solid-matrix luminescence analysis. Progress report, 15 June 1992--31 October 1994

    Hurtubise, R.J.


    Interaction models were developed for moisture effects on room-temperature fluorescence (RTF) and room-temperature phosphorescence (RTP) of compounds adsorbed on filter paper. The models described both dynamic and matrix quenching and also related the Young modulus of filter paper to quenching of phosphor on moist filter paper. Photophysical parameters for lumiphors in solution and on solid matrices were compared. Results showed that for some compounds, solid-matrix luminescence has greater analytical potential than solution luminescence. Also, the solid-matrix systems into one of two categories depending on how the intersystem crossing rate constants change with temperature. The first study was carried out on effects of heavy atom on solid-matrix luminescence. With some heavy atoms, maximum solid-matrix phosphorescence quantum yield was obtained at room temperature, and there was no need to use low temperature to obtain a strong phosphorescence signal. By studying solid-matrix luminescence properties of phosphors adsorbed on sodium acetate and deuterated sodium acetate, an interaction model was developed for p-aminobenzoic acid anion adsorbed on sodium acetate. It was shown that the energy-gap law was applicable to solid-matrix luminescence. Also, deuterated phenanthrene and undeuterated phenanthrene were used to study nonradiative transition of excited triplet state of adsorbed phosphors. Heat capacities of several solid matrices were obtained vs temperature and related to vibrational coupling of solid matrix with phosphor. Photophysical study was performed on the hydrolysis products of benzo(a)pyrene-DNA adducts. Also, an analytical method was developed for tetrols in human lung fractions. Work was initiated on the formation of room temperature glasses with glucose and trehalose. Also, work has begun for the development of an oxygen sensor by measuring the RTP quenching of triphenylene on filter paper.

  15. Development of Ceramic Solid-State Laser Host Material

    Prasad, Narasimha S.; Trivedi, Sudhir; Kutcher, Susan; Wang, Chen-Chia; Kim, Joo-Soo; Hommerich, Uwe; Shukla, Vijay; Sadangi, Rajendra


    Polycrystalline ceramic laser materials are gaining importance in the development of novel diode-pumped solid-state lasers. Compared to single-crystals, ceramic laser materials offer advantages in terms of ease of fabrication, shape, size, and control of dopant concentrations. Recently, we have developed Neodymium doped Yttria (Nd:Y2O3) as a solid-state ceramic laser material. A scalable production method was utilized to make spherical non agglomerated and monodisperse metastable ceramic powders of compositions that were used to fabricate polycrystalline ceramic material components. This processing technique allowed for higher doping concentrations without the segregation problems that are normally encountered in single crystalline growth. We have successfully fabricated undoped and Neodymium doped Yttria material up to 2" in diameter, Ytterbium doped Yttria, and erbium doped Yttria. We are also in the process of developing other sesquioxides such as scandium Oxide (Sc2O3) and Lutesium Oxide (Lu2O3) doped with Ytterbium, erbium and thulium dopants. In this paper, we present our initial results on the material, optical, and spectroscopic properties of the doped and undoped sesquioxide materials. Polycrystalline ceramic lasers have enormous potential applications including remote sensing, chem.-bio detection, and space exploration research. It is also potentially much less expensive to produce ceramic laser materials compared to their single crystalline counterparts because of the shorter fabrication time and the potential for mass production in large sizes.

  16. Host-Parasite Interaction: Parasite-Derived and -Induced Proteases That Degrade Human Extracellular Matrix

    Carolina Piña-Vázquez


    Full Text Available Parasitic protozoa are among the most important pathogens worldwide. Diseases such as malaria, leishmaniasis, amoebiasis, giardiasis, trichomoniasis, and trypanosomiasis affect millions of people. Humans are constantly threatened by infections caused by these pathogens. Parasites engage a plethora of surface and secreted molecules to attach to and enter mammalian cells. The secretion of lytic enzymes by parasites into host organs mediates critical interactions because of the invasion and destruction of interstitial tissues, enabling parasite migration to other sites within the hosts. Extracellular matrix is a complex, cross-linked structure that holds cells together in an organized assembly and that forms the basement membrane lining (basal lamina. The extracellular matrix represents a major barrier to parasites. Therefore, the evolution of mechanisms for connective-tissue degradation may be of great importance for parasite survival. Recent advances have been achieved in our understanding of the biochemistry and molecular biology of proteases from parasitic protozoa. The focus of this paper is to discuss the role of protozoan parasitic proteases in the degradation of host ECM proteins and the participation of these molecules as virulence factors. We divide the paper into two sections, extracellular and intracellular protozoa.

  17. Anormalous Optical Absorption in Porous Al_2O3 Host Matrix---Nano-Oxide Particle Nanocomposites

    Zhang, Lide; Zhang, Biao; Mo, Chimei


    Porous Al_2O3 host matrix---nano-γ-Fe_2O3 particle composites (porous nanocomposite) were prepared by pyrolysis of Fe(NO_3)_39H_2O in porous nano- Al_2O3 matrix at 250^0C. Comparing with simple nanocomposites formed by mixing nano-γ-Fe_2O3 and compacting at room temperature, followed by annealing at 250^0C, the following anomalous optical behaviors were observed: for porous nanocomposite containing 5% Fe_2O_3, the aborption edge shifts obviously from 827nm to 543nm, and with increasing dopping amount of Fe_2O3 from 5% to 70%, blue shift phenomina decreases. Namely, the absorption edge moves from 543nm to 710nm. The mechanism of shift of the absorption edge is discussed.

  18. Thixoforming of SiC ceramic matrix composites in pseudo-semi-solid state

    CHENG Yuan-sheng; LUO Shou-jing; DU Zhi-ming


    A new forming process, ceramic matrix composites thixoforming in pseudo-semi-solid state, was proposed based on powder metallurgy technology combined with the semi-solid metal forming process. The satellite angle-frames were prepared by this technology with Alp and SiCp materials mixed with different volume fractions. It is proved that it is feasible for the forming of the ceramic matrix composites by this technology through metallographic analyses and tensile tests. The results also show that the microstructures of samples are homogeneous and they have high hardness and certain plasticity.

  19. Local field enhancement at the core of cylindrical nanoinclusions embedded in a linear dielectric host matrix

    Y.A. Abbo


    Full Text Available In this paper we have discussed theoretical concepts and presented numerical results of local field enhancement at the core of different assemblages of metal/dielectric cylindrical nanoinclusions embedded in a linear dielectric host matrix. The obtained results show that for a composite with metal coated inclusions there exist two peak values of the enhancement factor at two different resonant frequencies. The existence of the second maxima becomes more important for a larger volume fraction of the metal part of the inclusion. For dielectric coated metal core inclusions and pure metal inclusions there is only one resonant frequency and one peak value of the enhancement factor. The enhancement of an electromagnetic wave is promising for the existence of nonlinear optical phenomena such as optical bistability which is important in optical communication and in optical computing such as optical switch and memory elements.

  20. Improving the Performance of Lithium-Sulfur Batteries by Employing Polyimide Particles as Hosting Matrixes.

    Gu, Pei-Yang; Zhao, Yi; Xie, Jian; Binte Ali, Nursimaa; Nie, Lina; Xu, Zhichuan J; Zhang, Qichun


    Sulfur cathodes with four polyimide (PI) compounds as hosting matrixes have been prepared through a simple one-step approach. These four PIs-S composites exhibited higher sulfur utilization and better cycling stability than pure sulfur. At a current rate of 300 mA g(-1), the initial discharge capacities of PI-1S, PI-2S, PI-3S, and BBLS reached 1120, 1100, 1150, and 1040 mAh g(-1), respectively. After the 30th cycle, PI-1S, PI-2S, PI-3S, BBLS and pristine sulfur powder still remained discharge capacities of 715, 673, 729, 643, and 550 mAh g(-1). Especially, PI-1S and PI-3S cathodes exhibit excellent cycling stability with the discharge capacities of 522 and 574 mAh g(-1) at the 450th cycle, respectively.

  1. Low surface area graphene/cellulose composite as a host matrix for lithium sulphur batteries

    Patel, Manu U. M.; Luong, Nguyen Dang; Seppälä, Jukka; Tchernychova, Elena; Dominko, Robert


    Graphene/cellulose composites were prepared and studied as potential host matrixes for sulphur impregnation and use in Li-S batteries. We demonstrate that with the proper design of a relatively low surface area graphene/cellulose composite, a high electrochemical performance along with good cyclability can be achieved. Graphene cellulose composites are built from two constituents: a two-dimensional electronic conductive graphene and cellulose fibres as a structural frame; together they form a laminar type of pore. The graphene sheets that uniformly anchor sulphur molecules provide confinement ability for polysulphides, sufficient space to accommodate sulphur volumetric expansion, a large contact area with the sulphur and a short transport pathway for both electrons and lithium ions. Nano-cellulose prevents the opening of graphene sheets due to the volume expansion caused by dissolved polysulphides during battery operation. This, in turn, prevents the diffusion of lithium polysulphides into the electrolyte, enabling a long cycle life.

  2. Visible luminescence of Al2O3 nanoparticles embedded in silica glass host matrix

    El Mir, L.; Amlouk, A.; Barthou, C.


    This paper deals with the sol gel elaboration and defects photoluminescence (PL) examination of Al2O3 nanocrystallites (size ˜30 nm) confined in glass based on silica aerogel. Aluminium oxide aerogels were synthesized using esterification reaction for hydrolysis of the precursor and supercritical conditions of ethyl alcohol for drying. The obtained nanopowder was incorporated in SiO2 host matrix. After heating under natural atmosphere at 1150 °C for 2 h, the composite Al2O3/SiO2 (AS) exhibited a strong PL bands at 400 600 and 700 900 nm in 78 300 K temperature range. PL excitation (PLE) measurements show different origins of the emission. It was suggested that OH-related radiative centres and non-bridging oxygen hole centres (NBOHCs) were responsible for the bands at 400 600 and 700 900 nm, respectively.

  3. Matrix supported tailored polymer for solid phase extraction of fluoride from variety of aqueous streams

    Thakur, Neha; Kumar, Sanjukta A.; Wagh, D.N. [Analytical Chemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085 (India); Das, Sadananda; Pandey, Ashok K. [Radiochemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085 (India); Kumar, Sangita D., E-mail: [Analytical Chemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085 (India); Reddy, A.V.R. [Analytical Chemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085 (India)


    Highlights: Black-Right-Pointing-Pointer Th complexed with poly (bis[2-(methacryloyloxy)-ethyl]phosphate) as tailored polymer membranes. Black-Right-Pointing-Pointer Membranes offered high capacity and selectivity for fluoride in aqueous media. Black-Right-Pointing-Pointer Quantitative uptake (80 {+-} 5%) of fluoride. Black-Right-Pointing-Pointer Fast sorption kinetics. Black-Right-Pointing-Pointer Reusability of polymer membranes. - Abstract: Fluoride related health hazards (fluorosis) are a major environmental problem in many regions of the world. It affects teeth; skeleton and its accumulation over a long period can lead to changes in the DNA structure. It is thus absolutely essential to bring down the fluoride levels to acceptable limits. Here, we present a new inorganic-organic hybrid polymer sorbent having tailored fixed-sites for fluoride sorption. The matrix supported poly (bis[2-(methacryloyloxy)-ethyl]phosphate) was prepared by photo-initiator induced graft-polymerization in fibrous and microporous (sheet) host poly(propylene) substrates. These substrates were conditioned for selective fluoride sorption by forming thorium complex with phosphate groups on bis[2-methacryloyloxy)-ethyl] phosphate (MEP). These tailored sorbents were studied for their selectivity towards fluoride in aqueous media having different chemical conditions. The fibrous sorbent was found to take up fluoride with a faster rate (15 min for Almost-Equal-To 76% sorption) than the sheet sorbent. But, the fluoride loading capacity of sheet sorbent (4320 mg kg{sup -1}), was higher than fibrous and any other sorbent reported in the literature so far. The sorbent developed in the present work was found to be reusable after desorption of fluoride using NaOH solution. It was tested for solid phase extraction of fluoride from natural water samples.

  4. Preparation of bioconjugates by solid-phase conjugation to ion exchange matrix-adsorbed carrier proteins

    Houen, G.; Olsen, D.T.; Hansen, P.R.;


    A solid-phase conjugation method utilizing carrier protein bound to an ion exchange matrix was developed. Ovalbumin was adsorbed to an anion exchange matrix using a batch procedure, and the immobilized protein was then derivatized with iodoacetic acid N-hydroxysuccinimid ester. The activated......, and immunization experiments with the eluted conjugates showed that the more substituted conjugates gave rise to the highest titers of glutathione antibodies. Direct immunization with the conjugates adsorbed to the ion exchange matrix was possible and gave rise to high titers of glutathione antibodies. Conjugates...... of ovalbumin and various peptides were prepared in a similar manner and used for production of peptide antisera by direct immunization with the conjugates bound to the ion exchanger. Advantages of the method are its solid-phase nature, allowing fast and efficient reactions and intermediate washings...

  5. Effect of host glass matrix on structural and optical behavior of glass-ceramic nanocomposite scintillators

    Brooke Barta, M.; Nadler, Jason H.; Kang, Zhitao; Wagner, Brent K.; Rosson, Robert; Kahn, Bernd


    Composite scintillator systems have received increased attention in recent years due to their promise for merging the radioisotope discrimination capabilities of single crystal scintillators with the high throughput scanning capabilities of portal monitors. However, producing the high light yield required for good energy resolution has proven challenging as scintillation photons are often scattered by variations in refractive index and agglomerated scintillator crystals within the composite. This investigation sought to mitigate these common problems by using glass-ceramic nanocomposite materials systems in which nanoscale scintillating crystallites are precipitated in a controlled manner from a transparent glass matrix. Precipitating crystallites in situ precludes nanoparticle agglomeration, and limiting crystallite size to 50 nm or less mitigates the effect of refractive index mismatch between the crystals and host glass. Cerium-doped gadolinium bromide (GdBr3(Ce)) scintillating crystals were incorporated into sodium-aluminosilicate (NAS) and alumino-borosilicate (ABS) host glass matrices, and the resulting glass-ceramic structures and luminescence behavior were characterized. The as-cast glass from the ABS system displayed a highly ordered microstructure that produced the highest luminescence intensity (light yield) of the samples studied. However, heat treating to form the glass-ceramic precipitated rare-earth oxide crystallites rather than rare-earth halides. This degraded light yield relative to the unaged sample.

  6. Characterization of and host response to tyramine substituted-hyaluronan enriched fascia extracellular matrix

    Chin, LiKang; Calabro, Anthony; Rodriguez, E. Rene; Tan, Carmela D.; Walker, Esteban


    Naturally-occurring biomaterial scaffolds derived from extracellular matrix (ECM) have been previously investigated for soft tissue repair. We propose to enrich fascia ECM with high molecular weight tyramine substituted-hyaluronan (TS-HA) to modulate inflammation associated with implantation and enhance fibroblast infiltration. As critical determinants of constructive remodeling, the host inflammatory response and macrophage polarization to TS-HA enriched fascia were characterized in a rat abdominal wall model. TS-HA treated fascia with cross-linking had a similar lymphocyte (P = 0.11) and plasma cell (P = 0.13) densities, greater macrophage (P = 0.001) and giant cell (P fascia, with or without cross-linking, exhibited a predominantly M2 pro-remodeling macrophage profile similar to water controls (P = 0.82), which is suggestive of constructive tissue remodeling. Our findings demonstrated that HA augmentation can alter the host response to an ECM, but the appropriate concentration and molecular weight needed to minimize chronic inflammation within the scaffold remains to be determined. PMID:21553156

  7. Solid-matrix luminescence interactions and analytical aspects of phenylphenol isomers on filter paper

    Purdy, B.B.


    The solid-matrix luminescence limits of detection, percent relative standard deviation, and linear concentration ranges were obtained for model compounds adsorbed on four different solid-matrices. Filter paper showed the best analytical merit. Several solid-matrix luminescence properties of phenylphenol isomers adsorbed on Whatman filter paper were investigated. In the presence of sodium halide salts, the luminescence intensity, lifetime, quantum yield and modulus data were obtained to study heavy-atom effects, quenching effects by salts and moisture, and photophysical processes and molecular interactions in the solid-matrix. For 4-phenylphenol, 3-phenylphenol, and 2-phenylphenol, heavy-atom effects were observed for the room-temperature luminescence intensities. The room-temperature phosphorescence was sensitive to the structural differences among the isomers. The quenching of room-temperature fluorescence by halides was best described by a modified Perrin quenching model which considered a quenching sphere volume and residual fluorescence. At room temperature, the phosphorescence intensities were quenched by moisture while the phosphorescence lifetimes and fluorescence intensities were slightly affected by moisture for 4-phenylphenol and 2-phenylphenol with sodium halides. It was concluded that the adsorption of moisture on the filter paper matrix decreased the matrix rigidity, and thus the phosphorescence intensities of adsorbed phosphors were diminished. The phosphors were well-protected in the matrix, and water molecules could not diffuse effectively to the phosphor molecules. The photophysical data showed how the absorbed energy was channeled into the various radiative and nonradiative processes. Modulus experiments showed there were no differences in the Young's modulus values of filter paper containing NaCl, NaBr, or NaI. A correlation was found between Young's modulus and phosphorescence intensity as a function of the water content adsorbed on

  8. Spectroscopy of lithium atoms sublimated from isolation matrix of solid Ne

    Sacramento, R. L.; Scudeller, L. A.; Lambo, R.; Crivelli, P.; Cesar, C. L.


    We have studied, via laser absorption spectroscopy, the velocity distribution of 7Li atoms released from a solid neon matrix at cryogenic temperatures. The Li atoms are implanted into the Ne matrix by laser ablation of a solid Li precursor. A heat pulse is then applied to the sapphire substrate sublimating the matrix together with the isolated atoms at around 12 K. We find interesting differences in the velocity distribution of the released Li atoms from the model developed for our previous experiment with Cr [R. Lambo, C. C. Rodegheri, D. M. Silveira, and C. L. Cesar, Phys. Rev. A 76, 061401-R (2007)], 10.1103/PhysRevA.76.061401. This may be due to the sublimation regime, which is at much lower flux for the Li experiment than for the Cr experiment, as well as to the different collisional cross sections between those species to the Ne gas. We find a drift velocity compatible with Li being thermally sublimated at 11-13 K, while the velocity dispersion around this drift velocity is low, around 5-7 K. With a slow sublimation of the matrix we can determine the penetration depth of the laser ablated Li atoms into the Ne matrix, an important information that is not usually available in most matrix isolation spectroscopy setups. The present results with Li, together with the previous results with Cr suggest this to be a general technique for obtaining cryogenic atoms, for spectroscopic studies, as well as for trap loading. The release of the isolated atoms is also a useful tool to study and confirm details of the matrix isolated atoms which are masked or poorly understood in the solid.

  9. Spectroscopy of lithium atoms sublimated from isolation matrix of solid Ne.

    Sacramento, R L; Scudeller, L A; Lambo, R; Crivelli, P; Cesar, C L


    We have studied, via laser absorption spectroscopy, the velocity distribution of (7)Li atoms released from a solid neon matrix at cryogenic temperatures. The Li atoms are implanted into the Ne matrix by laser ablation of a solid Li precursor. A heat pulse is then applied to the sapphire substrate sublimating the matrix together with the isolated atoms at around 12 K. We find interesting differences in the velocity distribution of the released Li atoms from the model developed for our previous experiment with Cr [R. Lambo, C. C. Rodegheri, D. M. Silveira, and C. L. Cesar, Phys. Rev. A 76, 061401(R) (2007)]. This may be due to the sublimation regime, which is at much lower flux for the Li experiment than for the Cr experiment, as well as to the different collisional cross sections between those species to the Ne gas. We find a drift velocity compatible with Li being thermally sublimated at 11-13 K, while the velocity dispersion around this drift velocity is low, around 5-7 K. With a slow sublimation of the matrix we can determine the penetration depth of the laser ablated Li atoms into the Ne matrix, an important information that is not usually available in most matrix isolation spectroscopy setups. The present results with Li, together with the previous results with Cr suggest this to be a general technique for obtaining cryogenic atoms, for spectroscopic studies, as well as for trap loading. The release of the isolated atoms is also a useful tool to study and confirm details of the matrix isolated atoms which are masked or poorly understood in the solid. © 2011 American Institute of Physics

  10. Recent advances in lipid nanoparticle formulations with solid matrix for oral drug delivery.

    Das, Surajit; Chaudhury, Anumita


    Lipid nanoparticles based on solid matrix have emerged as potential drug carriers to improve gastrointestinal (GI) absorption and oral bioavailability of several drugs, especially lipophilic compounds. These formulations may also be used for sustained drug release. Solid lipid nanoparticle (SLN) and the newer generation lipid nanoparticle, nanostructured lipid carrier (NLC), have been studied for their capability as oral drug carriers. Biodegradable, biocompatible, and physiological lipids are generally used to prepare these nanoparticles. Hence, toxicity problems related with the polymeric nanoparticles can be minimized. Furthermore, stability of the formulations might increase than other liquid nano-carriers due to the solid matrix of these lipid nanoparticles. These nanoparticles can be produced by different formulation techniques. Scaling up of the production process from lab scale to industrial scale can be easily achieved. Reasonably high drug encapsulation efficiency of the nanoparticles was documented. Oral absorption and bioavailability of several drugs were improved after oral administration of the drug-loaded SLNs or NLCs. In this review, pros and cons, different formulation and characterization techniques, drug incorporation models, GI absorption and oral bioavailability enhancement mechanisms, stability and storage condition of the formulations, and recent advances in oral delivery of the lipid nanoparticles based on solid matrix will be discussed. © 2010 American Association of Pharmaceutical Scientists

  11. Soxhlet-assisted matrix solid phase dispersion to extract flavonoids from rape (Brassica campestris) bee pollen.

    Ma, Shuangqin; Tu, Xijuan; Dong, Jiangtao; Long, Peng; Yang, Wenchao; Miao, Xiaoqing; Chen, Wenbin; Wu, Zhenhong


    Soxhlet-assisted matrix solid phase dispersion (SA-MSPD) method was developed to extract flavonoids from rape (Brassica campestris) bee pollen. Extraction parameters including the extraction solvent, the extraction time, and the solid support conditions were investigated and optimized. The best extraction yields were obtained using ethanol as the extraction solvent, silica gel as the solid support with 1:2 samples to solid support ratio, and the extraction time of one hour. Comparing with the conventional solvent extraction and Soxhlet method, our results show that SA-MSPD method is a more effective technique with clean-up ability. In the test of six different samples of rape bee pollen, the extracted content of flavonoids was close to 10mg/g. The present work provided a simple and effective method for extracting flavonoids from rape bee pollen, and it could be applied in the studies of other kinds of bee pollen.

  12. Ultra-thin Solid-State Li-Ion Electrolyte Membrane Facilitated by a Self-Healing Polymer Matrix.

    Whiteley, Justin M; Taynton, Philip; Zhang, Wei; Lee, Se-Hee


    Thin solid membranes are formed by a new strategy, whereby an in situ derived self-healing polymer matrix that penetrates the void space of an inorganic solid is created. The concept is applied as a separator in an all-solid-state battery with an FeS2 -based cathode and achieves tremendous performance for over 200 cycles. Processing in dry conditions represents a paradigm shift for incorporating high active-material mass loadings into mixed-matrix membranes.

  13. Molecular host-guest energy-transfer system with an ultralow amplified spontaneous emission threshold employing an ambipolar semiconducting host matrix.

    Toffanin, Stefano; Capelli, Raffaella; Hwu, Tsyr-Yuan; Wong, Ken-Tsung; Plötzing, Tobias; Först, Michael; Muccini, Michele


    We report on the characteristics of a host-guest lasing system obtained by coevaporation of an oligo(9,9-diarylfluorene) derivative named T3 with the red-emitter 4-(dicyanomethylene)-2-methyl-6-(p-dimethylaminostyryl)-4H-pyran dye (DCM). We demonstrate that the ambipolar semiconductor T3 can be implemented as an active matrix in the realization of a host-guest system in which an efficient energy transfer takes place from the T3 matrix to the lasing DCM molecules. We performed a detailed spectroscopic study on the system by systematically varying the DCM concentration in the T3 matrix. Measurements of steady-state photoluminescence (PL), PL quantum yield (PLQY), time-resolved picosecond PL, and amplified spontaneous emission (ASE) threshold are used to optimize the acceptor concentration at which the ASE from DCM molecules takes place with the lowest threshold. The sample with a DCM relative deposition ratio of 2% shows an ASE threshold as low as 0.6 kW/cm(2) and a net optical gain measured by femtosecond time-resolved pump-and-probe spectroscopy as high as 77 cm(-1). The reference model system Alq(3):DCM sample measured in exactly the same experimental conditions presents an one-order-of-magnitude higher ASE threshold. The ASE threshold of T3:DCM is the lowest reported to date for a molecular host-guest energy-transfer system, which makes the investigated blend an appealing system for use as an active layer in lasing devices. In particular, the ambipolar charge transport properties of the T3 matrix and its field-effect characteristics make the host-guest system presented here an ideal candidate for the realization of electrically pumped organic lasers.

  14. Bap, a biofilm matrix protein of Staphylococcus aureus prevents cellular internalization through binding to GP96 host receptor.

    Valle, Jaione; Latasa, Cristina; Gil, Carmen; Toledo-Arana, Alejandro; Solano, Cristina; Penadés, José R; Lasa, Iñigo


    The biofilm matrix, composed of exopolysaccharides, proteins, nucleic acids and lipids, plays a well-known role as a defence structure, protecting bacteria from the host immune system and antimicrobial therapy. However, little is known about its responsibility in the interaction of biofilm cells with host tissues. Staphylococcus aureus, a leading cause of biofilm-associated chronic infections, is able to develop a biofilm built on a proteinaceous Bap-mediated matrix. Here, we used the Bap protein as a model to investigate the role that components of the biofilm matrix play in the interaction of S. aureus with host cells. The results show that Bap promotes the adhesion but prevents the entry of S. aureus into epithelial cells. A broad analysis of potential interaction partners for Bap using ligand overlayer immunoblotting, immunoprecipitation with purified Bap and pull down with intact bacteria, identified a direct binding between Bap and Gp96/GRP94/Hsp90 protein. The interaction of Bap with Gp96 provokes a significant reduction in the capacity of S. aureus to invade epithelial cells by interfering with the fibronectin binding protein invasion pathway. Consistent with these results, Bap deficient bacteria displayed an enhanced capacity to invade mammary gland epithelial cells in a lactating mice mastitis model. Our observations begin to elucidate the mechanisms by which components of the biofilm matrix can facilitate the colonization of host tissues and the establishment of persistent infections.

  15. Composite Coatings with Ceramic Matrix Including Nanomaterials as Solid Lubricants for Oil-Less Automotive Applications

    Posmyk A.


    Full Text Available The paper presents the theoretical basis of manufacturing and chosen applications of composite coatings with ceramic matrix containing nanomaterials as a solid lubricant (AHC+NL. From a theoretical point of view, in order to reduce the friction coefficient of sliding contacts, two materials are required, i.e. one with a high hardness and the other with low shear strength. In case of composite coatings AHC+NL the matrix is a very hard and wear resistant anodic oxide coating (AHC whereas the solid lubricant used is the nanomaterial (NL featuring a low shear strength such as glassy carbon nanotubes (GC. Friction coefficient of cast iron GJL-350 sliding against the coating itself is much higher (0.18-0.22 than when it slides against a composite coating (0.08-0.14. It is possible to reduce the friction due to the presence of carbon nanotubes, or metal nanowires.


    Mariana A. Melaj


    Full Text Available The main purpose of this work was to optimize the preparation conditions of solid polymeric matrix based on Chitosan and Xanthan, to be used in the controlled release of fertilizers. KNO3 was chosen as model agrochemical to be released. Both individual polymers and the Xanthan:Chitosan complex are biocompatible, leaving a residue on the soil which is non-toxic. The influence of different variables on the release pattern was studied: the type of polymer, the pressed conditions of the tablets and the presence of a drug-free polymeric coating. The polymer that presented a more promising release profile was Xanthan. The compression pressure applied to prepare the tablets was a more relevant variable than the compression time, in its effect on the kinetics of release. It was determined that the coating of the polymer matrix with crosslinked chitosan-glutaraldehyde allows getting a larger release time.

  17. Mechanism of the radiation-induced transformations of fluoroform in solid noble gas matrixes

    Sosulin, Ilya S.; Shiryaeva, Ekaterina S.; Feldman, Vladimir I.


    The X-ray induced transformations in the CHF3/Ng systems (Ng=Ne, Ar, Kr or Xe) at 6 K were studied by FTIR spectroscopy. The radiation-induced decomposition of CHF3 was found to be rather inefficient in solid xenon with low ionization energy, which suggests primary significance of the positive hole transfer from matrix to the fluoroform molecule. CF3•, :CF2, CHF2• and CF4 were identified as the products of low-temperature radiolysis in all the noble gas matrixes. In addition, the anionic complex HF ⋯ CF2- was detected in Ne and Ar matrixes. The radiolysis also resulted in formation of noble gas compounds (HArF in argon, HKrF in krypton, and XeF2 in xenon). While XeF2 and HArF were essentially formed directly after irradiation (presumably due to reactions of 'hot' fluorine atoms), HKrF mainly resulted from annealing of irradiated samples below 20 K due to thermally induced mobility of trapped fluorine atoms. In both krypton and xenon matrixes, the thermally induced reactions of F atoms occur at lower temperatures than those of H atoms, while the opposite situation is observed in argon. The mechanisms of the radiation-induced processes and their implications are discussed.

  18. Solid-matrix luminescence analysis. Final technical report, June 15, 1986--June 14, 1995

    Hurtubise, R.J.


    In this report, the major results and conclusions of the research over the last two years and five months will be considered. The report discusses the physicochemical interactions discovered that are important for solid-matrix luminescence (SML), and the development of new interaction models which are very useful for the understanding the phenomena that are relevant for SML. The SML of 4-phenylphenol and 2-phenyl phenol adsorbed on filter paper is described. In addition, some new analytical methodology and applications are discussed.

  19. A transverse isotropic model for microporous solids: Application to coal matrix adsorption and swelling

    Espinoza, D. N.; Vandamme, M.; Dangla, P.; Pereira, J.-M.; Vidal-Gilbert, S.


    Understanding the adsorption-induced swelling in coal is critical for predictable and enhanced coal bed methane production. The coal matrix is a natural anisotropic disordered microporous solid. We develop an elastic transverse isotropic poromechanical model for microporous solids which couples adsorption and strain through adsorption stress functions and expresses the adsorption isotherm as a multivariate function depending on fluid pressure and solid strains. Experimental data from the literature help invert the anisotropic adsorptive-mechanical properties of Brzeszcze coal samples exposed to CO2. The main findings include the following: (1) adsorption-induced swelling can be modeled by including fluid-specific and pressure-dependent adsorption stress functions into equilibrium equations, (2) modeling results suggest that swelling anisotropy is mostly caused by anisotropy of the solid mechanical properties, and (3) the total amount of adsorbed gas measured by immersing coal in the adsorbate overestimates adsorption amount compared to in situ conditions up to ˜20%. The developed fully coupled model can be upscaled to determine the coal seam permeability through permeability-stress relationships.

  20. Solid-matrix luminescence analysis. Progress report, 1 November 1991--15 January 1993

    Hurtubise, R.J.


    Several interactions with lumiphors adsorbed on filter paper were elucidated from experiments with moisture, modulus and heavy-atom salts. The data were interpreted using static and dynamic quenching models, heavy-atom theory, and a theory related to the modulus of paper. With cyclodextrin-salt matrices, it was shown that 10% {alpha}-cyclodextrin/NaCl was very effective for obtaining strong room-temperature fluorescence and moderate room-temperature phosphorescence from adsorbed stereoisomeric tetrols. Extensive photophysical information was obtained for the four tetrols on 10% {alpha}-cyclodextrin/NaCl. The photophysical information acquired was used to develop a method for characterizing two of the tetrols. Work with model compounds adsorbed on deuterated sodium acetate showed that C-H vibrations in the undeuterated sodium acetate were not responsible for the deactivation of the excited triplet state in the model phosphors investigated. A considerable amount of solution luminescence and solid-matrix luminescence data were compared. The most important finding was that in several cases the room-temperature solid-matrix luminescence quantum yields were greater than the solution low-temperature quantum yield values.

  1. [Determination of aflatoxins in hot chilli products by matrix solid-phase dispersion and liquid chromatography].

    Zheng, Ping; Sheng, Xuan; Yu, Xiaofeng; Hu, Yanyun


    A new method based on matrix solid-phase dispersion (MSPD) extraction with neutral alumina and co-column purification with graphitized carbon black has been developed to determine aflatoxins B1, B2, G1, G2 in hot chilli products. The method includes liquid chromatography and fluorescence detection with on-line post-column derivatization with bromine. Optimization of different parameters, such as the type of solid supports for matrix dispersion and co-column clean-up was carried out. The recoveries of aflatoxins B1, B2, G1 and G2 were 95.4%, 87.3%, 91.5% and 92.6%, respectively, with relative standard deviations ranging from 3.3% to 6.1%. The limits of detection were in the range of 0.10 ng/g (B2, G2) to 0.25 ng/g (B1, G1). In addition, the comparison of the extraction and purification effect of MSPD with immunity affinity column showed that, MSPD is a valid method to analyze aflatoxins in hot chilli products.

  2. Determination of aflatoxins in rice samples by ultrasound-assisted matrix solid-phase dispersion.

    Manoochehri, Mahboobeh; Asgharinezhad, Ali Akbar; Safaei, Mahdi


    This work describes the application of ultrasound-assisted matrix solid-phase dispersion as an extraction and sample preparation approach for aflatoxins (B1, B2, G1 and G2) and subsequent determination of them by high-performance liquid chromatography-fluorescence detection. A Box-Behnken design in combination with response surface methodology was used to determine the affecting parameters on the extraction procedure. The influence of different variables including type of dispersing phase, sample-to-dispersing phase ratio, type and quantity of clean-up phase, ultrasonication time, ultrasonication temperature, nature and volume of the elution solvent was investigated in the optimization study. C18, primary-secondary amine (PSA) and acetonitrile were selected as dispersing phase, clean-up phase and elution solvent, respectively. The obtained optimized values were sample-to-dispersing phase ratio of 1 : 1, 60 mg of PSA, 11 min ultrasonication time, 30°C ultrasonication temperature and 4 mL acetonitrile. Under the optimal conditions, the limits of detection were ranged from 0.09 to 0.14 ng g(-1) and the precisions [relative standard deviation (RSD%)] were <8.6%. The recoveries of the matrix solid-phase dispersion process ranged from 78 to 83% with RSD <10% in all cases. Finally, this method was successfully applied to the extraction of trace amounts of aflatoxins in rice samples. © The Author [2014]. Published by Oxford University Press. All rights reserved. For Permissions, please email:

  3. Model Predictive Control of A Matrix-Converter Based Solid State Transformer for Utility Grid Interaction

    Xue, Yaosuo [ORNL


    The matrix converter solid state transformer (MC-SST), formed from the back-to-back connection of two three-to-single-phase matrix converters, is studied for use in the interconnection of two ac grids. The matrix converter topology provides a light weight and low volume single-stage bidirectional ac-ac power conversion without the need for a dc link. Thus, the lifetime limitations of dc-bus storage capacitors are avoided. However, space vector modulation of this type of MC-SST requires to compute vectors for each of the two MCs, which must be carefully coordinated to avoid commutation failure. An additional controller is also required to control power exchange between the two ac grids. In this paper, model predictive control (MPC) is proposed for an MC-SST connecting two different ac power grids. The proposed MPC predicts the circuit variables based on the discrete model of MC-SST system and the cost function is formulated so that the optimal switch vector for the next sample period is selected, thereby generating the required grid currents for the SST. Simulation and experimental studies are carried out to demonstrate the effectiveness and simplicity of the proposed MPC for such MC-SST-based grid interfacing systems.

  4. Solid waste bin level detection using gray level co-occurrence matrix feature extraction approach.

    Arebey, Maher; Hannan, M A; Begum, R A; Basri, Hassan


    This paper presents solid waste bin level detection and classification using gray level co-occurrence matrix (GLCM) feature extraction methods. GLCM parameters, such as displacement, d, quantization, G, and the number of textural features, are investigated to determine the best parameter values of the bin images. The parameter values and number of texture features are used to form the GLCM database. The most appropriate features collected from the GLCM are then used as inputs to the multi-layer perceptron (MLP) and the K-nearest neighbor (KNN) classifiers for bin image classification and grading. The classification and grading performance for DB1, DB2 and DB3 features were selected with both MLP and KNN classifiers. The results demonstrated that the KNN classifier, at KNN = 3, d = 1 and maximum G values, performs better than using the MLP classifier with the same database. Based on the results, this method has the potential to be used in solid waste bin level classification and grading to provide a robust solution for solid waste bin level detection, monitoring and management.

  5. Elaboration and characterization of TiO2 nanoparticles incorporated in SiO2 host matrix

    Amlouk, A.; El Mir, L.; Kraiem, S.; Alaya, S.


    Nanometer-scale TiO2 particles have been synthesized by sol gel method. It was incorporated in a glass-based silica aerogel. The composite was characterized by various techniques such as particle size analysis, scanning electron microscopy (SEM), atomic force microscopy (AFM), transmission electron microscopy (TEM), X-ray diffraction (XRD), infrared spectroscopy (IR) and photoluminescence (PL). The bulk glass presents a strong luminescence at wavelengths ranging from 750 to 950 nm. This PL was attributed to various non-bridging oxygen hole centers (NBOHCs) defects resulting from thermal treatment and crystallization of TiO2 at the interface between titania nanoparticles and silica host matrix.

  6. Continuum modeling of a porous solid with pressure-sensitive dilatant matrix

    Guo, T. F.; Faleskog, J.; Shih, C. F.

    The pressure-sensitive plastic response of a material has been studied in terms of the intrinsic sensitivity of its yield stress to pressure and the presence and growth of cavities. This work focuses on the interplay between these two distinctly different mechanisms and the attendant material behavior. To this end, a constitutive model is proposed taking both mechanisms into account. Using Gurson's homogenization, an upper bound model is developed for a voided solid with a plastically dilatant matrix material. This model is built around a three-parameter axisymmetric velocity field for a unit sphere containing a spherical void. The void is also subjected to internal pressure; this can be relevant for polymeric adhesives permeated by moisture that vaporizes at elevated temperatures. The plastic response of the matrix material is described by Drucker-Prager's yield criterion and an associated flow rule. The resulting yield surface and porosity evolution law of the homogenized constitutive model are presented in parametric form. Using the solutions to special cases as building blocks, approximate models with explicit forms are proposed. The parametric form and an approximate explicit form are compared against full-field solutions obtained from finite element analysis. They are also studied for loading under generalized tension conditions. These computational simulations shed light on the interplay between the two mechanisms and its enhanced effect on yield strength and plastic flow. Among other things, the tensile yield strength of the porous solid is greatly reduced by the internal void pressure, particularly when a liquid/vapor phase is the source of the internal pressure.

  7. Application of matrix solid-phase dispersion and high-performance liquid chromatography for determination of sulfonamides in honey.

    Zou, Qiong-Hui; Wang, Jin; Wang, Xiang-Feng; Liu, Yuan; Han, Jie; Hou, Feier; Xie, Meng-Xia


    A novel method for simultaneous determination of 8 sulfonamide residues (sulfathiazole, sulfapyridine, sulfadiazine, sulfamerazine, sulfamonome-thoxine, sulfachloropyridazine, sulfamethoxazole, and sulfadimethoxine) in honey samples by high-performance liquid chromatography (HPLC) has been developed on the basis of precolumn derivatization with 9-fluorenylmethyl-chloroformate (FMOC-Cl). Sulfonamide residues in honey samples were extracted and purified by matrix solid-phase dispersion with C18 as the solid support. The residues were derivatized by FMOC-CI, and the FMOC-sulfonamide derivatives were further purified by solid-phase extraction with silica gel as the solid support prior to HPLC analysis. The average recoveries for most sulfonamide compounds at different spiking levels (from 10 to 250 microg/kg) were > 70% with relative standard deviations < 16%, and their limits of detection were 4.0 microg/kg. The established analytical method has high sensitivity and repeatability and can be applicable for determining the sulfonamide residues in various honey matrixes.

  8. Study of complex matrix effect on solid phase microextraction for biological sample analysis.

    Jiang, Ruifen; Xu, Jianqiao; Zhu, Fang; Luan, Tiangang; Zeng, Feng; Shen, Yong; Ouyang, Gangfeng


    Solid phase microextraction (SPME) has become a useful tool for in vivo monitoring the behavior of environmental organic pollutants in biological species due to its simplicity, relatively non-invasive, and cost-effective manner. However, the complex matrices in biological samples could significantly influence the extraction kinetic, and bias the quantification result. In this study, we investigated the effect of complex matrix on the extraction kinetic of SPME for biological sample analysis. Two sample matrices, phosphate-buffered saline (PBS) with bovine serum albumin (BSA) and agarose gel with BSA were used to simulate the biological fluid and tissue. Results showed that the addition of BSA significantly enhanced the mass transfer of organic compounds onto SPME fiber in both PBS buffer and gel sample. Enhancement factors ranging from 1.3 to 27, and 2.0 to 80 were found for all selected polyaromatic hydrocarbons (PAHs) in PBS buffer and agarose gel with BSA concentration of 0.1-5%, respectively. Then, an improved theoretical model was applied to quantify the observed enhancement effect, and the result showed that the predicted sampling time constant agreed well with the experimental one in complex matrix. Furthermore, a simplified equation was proposed for the real biological sample analysis.

  9. Evaluation of Solid Modeling Software for Finite Element Analysis of Woven Ceramic Matrix Composites

    Nemeth, Noel N.; Mital, Subodh; Lang, Jerry


    Three computer programs, used for the purpose of generating 3-D finite element models of the Repeating Unit Cell (RUC) of a textile, were examined for suitability to model woven Ceramic Matrix Composites (CMCs). The programs evaluated were the open-source available TexGen, the commercially available WiseTex, and the proprietary Composite Material Evaluator (COMATE). A five-harness-satin (5HS) weave for a melt-infiltrated (MI) silicon carbide matrix and silicon carbide fiber was selected as an example problem and the programs were tested for their ability to generate a finite element model of the RUC. The programs were also evaluated for ease-of-use and capability, particularly for the capability to introduce various defect types such as porosity, ply shifting, and nesting of a laminate. Overall, it was found that TexGen and WiseTex were useful for generating solid models of the tow geometry; however, there was a lack of consistency in generating well-conditioned finite element meshes of the tows and matrix. TexGen and WiseTex were both capable of allowing collective and individual shifting of tows within a ply and WiseTex also had a ply nesting capability. TexGen and WiseTex were sufficiently userfriendly and both included a Graphical User Interface (GUI). COMATE was satisfactory in generating a 5HS finite element mesh of an idealized weave geometry but COMATE lacked a GUI and was limited to only 5HS and 8HS weaves compared to the larger amount of weave selections available with TexGen and WiseTex.

  10. Matrix compatible solid phase microextraction coating, a greener approach to sample preparation in vegetable matrices.

    Naccarato, Attilio; Pawliszyn, Janusz


    This work proposes the novel PDMS/DVB/PDMS fiber as a greener strategy for analysis by direct immersion solid phase microextraction (SPME) in vegetables. SPME is an established sample preparation approach that has not yet been adequately explored for food analysis in direct immersion mode due to the limitations of the available commercial coatings. The robustness and endurance of this new coating were investigated by direct immersion extractions in raw blended vegetables without any further sample preparation steps. The PDMS/DVB/PDMS coating exhibited superior features related to the capability of the external PDMS layer to protect the commercial coating, and showed improvements in terms of extraction capability and in the cleanability of the coating surface. In addition to having contributed to the recognition of the superior features of this new fiber concept before commercialization, the outcomes of this work serve to confirm advancements in the matrix compatibility of the PDMS-modified fiber, and open new prospects for the development of greener high-throughput analytical methods in food analysis using solid phase microextraction in the near future.

  11. Quasi-solid-state dye-sensitized solar cells with cyanoacrylate as electrolyte matrix

    Lu, Shengli [Linz Institute for Organic Solar Cells (LIOS), Johannes Kepler University Linz, Altenbergerstr. 69, A-4040 Linz (Austria); Institute for Organic Solar Energy Opto-Electronic Materials, College of Biological and Chemical Engineering, Zhejiang University of Science and Technology, Hangzhou 310012 (China); Koeppe, Robert; Guenes, Serap; Sariciftci, Niyazi Serdar [Linz Institute for Organic Solar Cells (LIOS), Johannes Kepler University Linz, Altenbergerstr. 69, A-4040 Linz (Austria)


    A quasi-solid-state dye-sensitized solar cells (DSSCs) employing a commercial glue (''SuperGlue {sup registered} '') as electrolyte matrix was fabricated. The cyano groups of the cyanoacrylate can form a supramolecular complex with tetrapropylammonium cations. This immobilizes the cations and therefore might lead to a favored anionic charge transport necessary for a good performance of the iodide/triiodide electrolytic conductor. Obtaining energy conversion efficiencies of more than 4% under 100 mW/cm{sup 2} of simulated A.M. 1.5 illumination, the cyanoacrylate quasi-solid-state electrolyte is an ordinary and low-cost compound which has fast drying property and offers significant advantages in the fabrication of solar cells and modules as it is in itself is a very good laminating agent. The influences of different porous layer thicknesses of titanium oxide and various kinds of cations on DSSC performance and long-term stability are presented. (author)

  12. Extracellular matrix metalloproteinase inducer (EMMPRIN) and matrix metalloproteinases (MMPs) as regulators of tumor-host interaction in a spontaneous metastasis model in rats.

    Donadio, Ana Carolina; Remedi, María Mónica; Susperreguy, Sebastián; Frede, Silvia; Gilardoni, Mónica Beatriz; Tang, Yi; Pellizas, Claudia Gabriela; Yan, Li


    EMMPRIN has a role in invasion and metastasis through the induction of MMPs and the consequent modulation of cell-substrate and cell-cell adhesion processes. The present study evaluates the expression of EMMPRIN protein and MMP-2/9 activity in tumor and parenchymal cells in a spontaneous metastasis model in rats. Moreover, we explore the regulation of EMMPRIN and MMP-9 by tumor-epithelial cell interactions in vitro. By zymography, we observed an increased proMMP-9 expression in both metastasized liver and spleen samples from tumor bearing rats. Immunohistochemical studies showed EMMPRIN-positive tumor cells in tumor biopsies as well as in spleen and liver samples from tumor bearing rats. Interestingly, a significant increase in EMMPRIN expression in hepatic cells was also detected. The regulation of EMMPRIN expression in tumor and liver cells in response to tumor-host interaction was investigated in vitro through a tumor cell line culture on extracellular matrix (ECM) molecules or in co-culture with normal rat liver cells (BRL3A cells). No significant changes in EMMPRIN expression were detected in tumor cells cultured on ECM molecules. On the other hand, EMMPRIN protein and MMP-9 mRNA expression were induced in BRL3A cells. The increase in EMMPRIN expression in BRL3A cells was inhibited by an anti-EMMPRIN antibody. These results reinforce the main role of EMMPRIN mediating tumor-host interactions that may evolve new opportunities for therapeutic interventions.

  13. Fabrication of metal matrix composite by semi-solid powder processing

    Wu, Yufeng [Iowa State Univ., Ames, IA (United States)


    Various metal matrix composites (MMCs) are widely used in the automotive, aerospace and electrical industries due to their capability and flexibility in improving the mechanical, thermal and electrical properties of a component. However, current manufacturing technologies may suffer from insufficient process stability and reliability and inadequate economic efficiency and may not be able to satisfy the increasing demands placed on MMCs. Semi-solid powder processing (SPP), a technology that combines traditional powder metallurgy and semi-solid forming methods, has potential to produce MMCs with low cost and high efficiency. In this work, the analytical study and experimental investigation of SPP on the fabrication of MMCs were explored. An analytical model was developed to understand the deformation mechanism of the powder compact in the semi-solid state. The densification behavior of the Al6061 and SiC powder mixtures was investigated with different liquid fractions and SiC volume fractions. The limits of SPP were analyzed in terms of reinforcement phase loading and its impact on the composite microstructure. To explore adoption of new materials, carbon nanotube (CNT) was investigated as a reinforcing material in aluminum matrix using SPP. The process was successfully modeled for the mono-phase powder (Al6061) compaction and the density and density distribution were predicted. The deformation mechanism at low and high liquid fractions was discussed. In addition, the compaction behavior of the ceramic-metal powder mixture was understood, and the SiC loading limit was identified by parametric study. For the fabrication of CNT reinforced Al6061 composite, the mechanical alloying of Al6061-CNT powders was first investigated. A mathematical model was developed to predict the CNT length change during the mechanical alloying process. The effects of mechanical alloying time and processing temperature during SPP were studied on the mechanical, microstructural and

  14. Solid H2 versus solid noble-gas environment: Influence on photoinduced hydrogen-atom transfer in matrix-isolated 4(3H)-pyrimidinone

    Lapinski, Leszek; Nowak, Maciej J.; Rostkowska, Hanna


    UV-induced transformations have been studied for 4(3H)-pyrimidinone monomers isolated in low-temperature Ar, Ne, n-D2, and n-H2 matrices. The observed photochemical behavior of the compound drastically depended on the solid matrix environment. For 4(3H)-pyrimidinone isolated in solid Ar, the UV-induced phototautomeric transformation was clearly the dominating process, leading to a nearly quantitative conversion of the oxo reactant into the hydroxy product. For solid Ne environment, the oxo → hydroxy transformation was still the major photoprocess, but yielding less of the hydroxy product (ca. 64% of the yield in solid Ar). For 4(3H)-pyrimidinone isolated in solid n-H2, the oxo → hydroxy phototautomeric conversion did not occur (or occurred at a very tiny scale). Also for deuterated 4(3D)-pyrimidinone isolated in solid hydrogen, the analogous oxo → deuteroxy phototransformation was not observed. Finally, for the compound trapped in solid n-D2, the oxo → hydroxy phototautomerism clearly occurred, but the yield of the hydroxy tautomer was small (ca. 18% of the yield in solid Ar). Apart from hydrogen-atom-transfer processes, two other phototransformations: generation of open-ring conjugated ketene and valence Dewar isomer were observed for the compound isolated in Ar, Ne, n-D2, and n-H2 matrices.

  15. Polymer-nanocomposite brush-like architectures as an all-solid electrolyte matrix.

    Gowneni, Soujanya; Ramanjaneyulu, Kota; Basak, Pratyay


    Herein, we report on polymer-nanocomposites with brush-like architectures and evaluate their feasibility as an all-solid electrolyte matrix supporting Li(+)-ion conduction. Showcased as a first example in the domain of electrolyte research, the study probes several key factors, such as (i) core morphology, (ii) surface modifiers/functionality, (iii) grafting length, and (iv) density of the brushes, and determines their role on the overall electrochemical properties of these nanostructured organic-inorganic hybrids. Nanostructured titania was synthesized via wet-chemical approaches using either controlled hydrolysis or hydrothermal methods. Exercising suitable control on reaction parameters led to well-defined morphologies/phases, such as nanoparticles, nanospindles, nanourchins, nanorods or nanotubes, in either anatase, rutile or mixed forms. Covalent anchoring on titania nanostructures was achieved using dopamine, gallic acid and glycerol as small organic moieties. A one-pot process of priming the available surface functional groups postmodification with isocyanate chemistry was followed by grafting polyethylene glycol monomethyl ethers of desired chain lengths. Finally, complexation with lithium salt yielded electrolyte compositions where the ethylene oxide (EO) fractions aid in ion-solvation with ease. The synthesized materials were characterized in detail employing XRD, TEM, DRS-UV, FTIR, micro-Raman, TG-DTA and DSC at each stage to confirm the products and ascertain the physicochemical properties. Comprehensive evaluation using temperature-step electrochemical impedance spectroscopy (EIS) of these brush-like nanocomposites provided crucial leads toward establishing a plausible physical model for the system and understanding the mechanism of ion transport in these all-solid matrices. The preliminary results on ionic conductivity (σ) obtained for some of the compositions are estimated to be within the range of ∼10(-4) to 10(-5) S cm(-1) in the temperature

  16. Matrix Metalloproteinase-9 and Haemozoin: Wedding Rings for Human Host and Plasmodium falciparum Parasite in Complicated Malaria

    Mauro Prato


    Full Text Available It is generally accepted that the combination of both Plasmodium falciparum parasite and human host factors is involved in the pathogenesis of complicated severe malaria, including cerebral malaria (CM. Among parasite products, the malarial pigment haemozoin (HZ has been shown to impair the functions of mononuclear and endothelial cells. Different CM models were associated with enhanced levels of matrix metalloproteinases (MMPs, a family of proteolytic enzymes able to disrupt subendothelial basement membrane and tight junctions and shed, activate, or inactivate cytokines, chemokines, and other MMPs through cleavage from their precursors. Among MMPs, a good candidate for targeted therapy might be MMP-9, whose mRNA and protein expression enhancement as well as direct proenzyme activation by HZ have been recently investigated in a series of studies by our group and others. In the present paper the role of HZ and MMP-9 in complicated malaria, as well as their interactions, will be discussed.

  17. Semi solid matrix formulations of meloxicam and tenoxicam: an in vitro and in vivo evaluation.

    Alladi, Saritha; Shastri, Nalini R


    The objective of this study was to improve the dissolution and subsequently the therapeutic efficacy of poorly water soluble BCS class-II drugs meloxicam and tenoxicam, by lipid semi solid matrix (SSM) systems filled in hard gelatin capsules by liquid fill technology. The present research involved preparation of SSM formulations using Gelucire 44/14 as a carrier due to its self emulsifying, wetting and hydrophilic properties. The SSM capsules were characterized by assay, in vitro dissolution studies, moisture uptake, FTIR and DSC. The optimized formulations were also evaluated for their in vivo anti inflammatory activity in rat model. Six to ten fold enhancement in vitro drug release, in both acidic and basic media, was obtained with formulations containing drug to carrier in 1:6 ratio. The absence of drug peak in DSC scans indicated complete dissolution of the drug in carrier, while IR revealed no chemical interaction of pure drug and Gelucire 44/14. The optimized SSM formulations of meloxicam and tenoxicam showed a rapid decrease in paw edema with a significant increase in anti-inflammatory activity. The SSM formulations were successful in providing rapid release of drugs with improved dissolution and in vivo anti-inflammatory activity by liquid fill technology in hard gelatin capsules.

  18. Stabilization of pH in solid-matrix hydroponic systems

    Frick, J.; Mitchell, C. A.


    2-[N-morpholino]ethanesulfonic acid (MES) buffer or Amberlite DP-1 (cation-exchange resin beads) were used to stabilize substrate pH of passive-wicking, solid-matrix hydroponic systems in which small canopies of Brassica napus L. (CrGC 5-2, genome : ACaacc) were grown to maturity. Two concentrations of MES (5 or 10 mM) were included in Hoagland 1 nutrient solution. Alternatively, resin beads were incorporated into the 2 vermiculite : 1 perlite (v/v) growth medium at 6% or 12% of total substrate volume. Both strategies stabilized pH without toxic side effects on plants. Average seed yield rates for all four pH stabilization treatments (13.3 to 16.9 g m-2 day-1) were about double that of the control (8.2 g m-2 day-1), for which there was no attempt to buffer substrate pH. Both the highest canopy seed yield rate (16.9 g m-2 day-1) and the highest shoot harvest index (19.5%) occurred with the 6% resin bead treatment, even though the 10 mM MES and 12% bead treatments maintained pH within the narrowest limits. The pH stabilization methods tested did not significantly affect seed oil and protein contents.

  19. Application Of Density Matrix Methods To Quadrupolar Spins In Solid State Nmr And Nqr

    Ageev, S Z


    Spin dynamics in solid state NMR and NQR are studied using spin density matrix theory. First, the response of spin 7/2 subject to the first order quadrupolar interaction, excited by one and two pulse sequences is examined. Specific pulse sequences with appropriate phase cycling designed for detection of MQ coherences developed during the first pulse are calculated analytically. The results are applied to the determination of quadrupolar parameters and true chemical shifts utilizing a 1D nutation experiment. Solomon echoes under soft pulse excitation are also considered for spin 7/2. Second, analytical solutions of off-resonance nutation line intensities for spin 3/2 are presented. The first order quadrupolar interaction is retained during the pulse. The third case puts forward a new theory of composite pulses in NQR. Shaped pulses are also considered. The calculation is valid for a non-zero asymmetry parameter and arbitrary orientation of the rf field. The results are generalized for half integer spins of mag...

  20. A single sorbent for tetracycline enrichment and subsequent solid-matrix time-resolved luminescence

    Liu Linshu [Eastern Regional Research Center, Agriculture Research Service, US Department of Agriculture, 600 East Mermaid Lane, Wyndmoor, PA 19038 (United States)]. E-mail:; Chen Guoying [Eastern Regional Research Center, Agriculture Research Service, US Department of Agriculture, 600 East Mermaid Lane, Wyndmoor, PA 19038 (United States); Fishman, Marshall L. [Eastern Regional Research Center, Agriculture Research Service, US Department of Agriculture, 600 East Mermaid Lane, Wyndmoor, PA 19038 (United States)


    The aim of this study was to search for a sorbent that could act as an extraction phase and as a support for solid-matrix time-resolved luminescence (SMTRL). Four potential sorbents were investigated for this purpose using tetracycline (TC) as a model analyte. Sorbents prepared from C18 silica gel or calcium cross-linked pectin gel were able to extract TC from dilute solutions. Europium(III)-TC complex adsorbed on the surface of C18 generated the most intense TRL signal when measured at {lambda}{sub ex} = 388 nm and {lambda}{sub em} = 615 nm. This method achieved a 1 ng/ml limit of detection (LOD) with a 100 {mu}l sample solution in a repeated spotting mode. Hyphenation of sorbent extraction and SMTRL was demonstrated using C18. This method is suitable for screening of TC in foods or aqueous solutions and can be extended to other luminescent lanthanide-chelating analytes in physiological or environmental samples.

  1. Evaluation of Antibacterial Enrofloxacin in Eggs by Matrix Solid Phase Dispersion-Flow Injection Chemiluminescence

    Xiaocui Duan


    Full Text Available The study based on the chemiluminescence (CL reaction of potassium ferricyanide and luminol in sodium hydroxide medium, enrofloxacin (ENRO could dramatically enhance CL intensities and incorporated with matrix solid-phase dispersion (MSPD technique (Florisil used as dispersant, dichloromethane eluted the target compounds. A simple flow injection chemiluminescence (FL-CL method with MSPD technique for determination of ENRO in eggs was described. Under optimal conditions, the CL intensities were linearly related to ENRO concentration ranging from 4.0×10-8 g.L−1 to 5.0×10-5 g.L−1, with a correlation coefficient of 0.9989 and detection limit of 5.0×10-9 g.L−1. The relative standard deviation was 3.6% at an ENRO concentration of 2.0×10-6 g.L−1. Our testing technique can help ensure food safety, and thus, protect public health.

  2. Electron spin-lattice relaxation in solid ethanol: the effect of nitroxyl radical hydrogen bonding and matrix disorder

    Kveder, Marina; Jokić, Milan; Makarević, Janja; Rakvin, Boris


    The electron spin-lattice relaxation of TEMPO and TEMPONE was measured at temperatures between 5 and 80 K in crystalline and glassy ethanol using X-band electron paramagnetic resonance spectroscopy. The experimental data at the lowest temperatures studied were explained in terms of electron-nuclear dipolar interaction between the paramagnetic center and the localized excitations, whereas at higher temperatures low-frequency vibrational modes from the host matrix and Raman processes should be considered. The strong impact of hydrogen bonding between the dopant molecule and ethanol host on the spin relaxation was observed in ethanol glass whereas in crystalline ethanol both paramagnetic guest molecules behaved similarly.

  3. Free base tetraazaporphine isolated in inert gas hosts: Matrix influence on its spectroscopic and photochemical properties

    Henchy, Chris; McCaffrey, John G.; Arabei, Serguei; Pavich, Tatiana; Galaup, Jean-Pierre; Shafizadeh, Niloufar; Crépin, Claudine


    The absorption, fluorescence, and excitation spectra of free base tetraazaporphine (H2TAP) trapped in Ne, N2, and Ar matrices have been recorded at cryogenic temperatures. Normal Raman spectra of H2TAP were recorded in KBr discs and predicted with density functional theory (DFT) using large basis sets calculations. The vibrational frequencies observed in the Raman Spectrum exhibit reasonable agreement with those deduced from the emission spectra, as well as with frequencies predicted from large basis set DFT computations. The upper state vibrational frequencies, obtained from highly resolved, site selected excitation spectra, are consistently lower than the ground state frequencies. This contrasts with the situation in free base phthalocyanine, where the upper state shows little changes in vibrational frequencies and geometry when compared with the ground state. Investigations of the photochemical properties of H2TAP isolated in the three matrices have been performed using the method of persistent spectral hole-burning (PSHB). This technique has been used to reveal sites corresponding to distinct N-H tautomers which were not evident in the absorption spectra. An analysis of the holes and antiholes produced with PSHB in the Qx (0-0) absorption band made it possible to identify inter-conversion of distinct host sites.

  4. Host-derived Loss of Dentin Matrix Stiffness Associated with Solubilization of Collagen

    Carrilho, Marcela R.; Tay, Franklin R.; Donnelly, Adam M.; Agee, Kelli A.; Tjäderhane, Leo; Mazzoni, Annalisa; Breschi, Lorenzo; Foulger, Stephen; Pashley, David H.


    Matrix metalloproteinases (MMPs) bound to dentin matrices are activated during adhesive bonding procedures and are thought to contribute to the progressive degradation of resin-dentin bonds over time. The purpose of this study was to evaluate the changes in mechanical, biochemical and structural properties of demineralized dentin treated with or without chlorhexidine (CHX), a known MMP-inhibitor. After demineralizing dentin beams in EDTA or phosphoric acid (PA), the baseline modulus of elasticity (E) of each beam was measured by 3-point flexure. Specimens were pretreated with water (control) or with 2% CHX (experimental) and then incubated in artificial saliva (AS) at 37°C for 4 weeks. The E of each specimen was remeasured weekly and, the media was analyzed for solubilized dentin collagen at first and fourth week of incubation. Some specimens were processed for electron microscopy (TEM) immediately after demineralization and after 4 weeks of incubation. In EDTA and PA-demineralized specimens, the E of the control specimens fell (p<0.05) after incubation in AS, while there were no changes in E in the CHX-pretreated specimens over time. More collagen was solubilized from PA-demineralized controls (p<0.05) than from EDTA-demineralized matrices after 1 or 4 weeks. Less collagen (p<0.05) was solubilized from CHX-pretreated specimens demineralized in EDTA compared to PA. TEM examination of control beams revealed that prolonged demineralization of dentin in 10% PA (12 h) did not denature the collagen fibrils. PMID:19090493

  5. Host-derived loss of dentin matrix stiffness associated with solubilization of collagen.

    Carrilho, Marcela R; Tay, Franklin R; Donnelly, Adam M; Agee, Kelli A; Tjäderhane, Leo; Mazzoni, Annalisa; Breschi, Lorenzo; Foulger, Stephen; Pashley, David H


    Matrix metalloproteinases (MMPs) bound to dentin matrices are activated during adhesive bonding procedures and are thought to contribute to the progressive degradation of resin-dentin bonds over time. The purpose of this study was to evaluate the changes in mechanical, biochemical, and structural properties of demineralized dentin treated with or without chlorhexidine (CHX), a known MMP-inhibitor. After demineralizing dentin beams in EDTA or phosphoric acid (PA), the baseline modulus of elasticity (E) of each beam was measured by three-point flexure. Specimens were pretreated with water (control) or with 2% CHX (experimental) and then incubated in artificial saliva (AS) at 37 degrees C for 4 weeks. The E of each specimen was remeasured weekly and, the media was analyzed for solubilized dentin collagen at first and fourth week of incubation. Some specimens were processed for electron microscopy (TEM) immediately after demineralization and after 4 weeks of incubation. In EDTA and PA-demineralized specimens, the E of the control specimens fell (p < 0.05) after incubation in AS, whereas there were no changes in E of the CHX-pretreated specimens over time. More collagen was solubilized from PA-demineralized controls (p < 0.05) than from EDTA-demineralized matrices after 1 or 4 weeks. Less collagen (p < 0.05) was solubilized from CHX-pretreated specimens demineralized in EDTA compared with PA. TEM examination of control beams revealed that prolonged demineralization of dentin in 10% PA (12 h) did not denature the collagen fibrils.

  6. Analytical criterion for porous solids containing cylindrical voids in an incompressible matrix exhibiting tension-compression asymmetry

    Cazacu, Oana; Stewart, Joel B.


    A new analytic plastic potential is developed using a rigorous limit analysis approach. Conditions of homogeneous boundary strain rate are imposed on every cylinder concentric with the cavity. It is shown that, due to the tension-compression asymmetry of the incompressible matrix, the third invariant of the stress deviator has a strong influence on the yielding of the porous solid. New and intriguing results are obtained; namely, for axisymmetric loadings and plane strain conditions, the stress state at yielding is not hydrostatic. In the case when the matrix has the same yield in tension as in compression, the new criterion reduces to Gurson's criterion for cylindrical voids.

  7. Wear of semi-solid rheocast SiCp/Al metal matrix composites

    Curle, UA


    Full Text Available casting of SiC metal matrix composites. The metal matrix consisting of nearly spherical proeutectic a(Al) globules was produced. Spheroidization of fibrous eutectic silicon took place upon heat treatment of the as-cast metal matrix composites (MMCs...

  8. Determination of Sudan Residues in Sausage by Matrix Solid-Phase Dispersion and High-Performance Liquid Chromatography.

    Zhai, Yujuan; Cheng, Jianhua


    A method based on matrix solid-phase dispersion and high-performance liquid chromatography was applied to the determination of four Sudan red residues in sausage. The proposed method required only 0.5 g sample. The neutral alumina was used as the dispersant sorbent while n-hexane containing 10% (v/v) acetone was used as the eluting solvent. The recoveries in samples ranged from 76.4 to 111.0% and relative standard deviations were sausage.

  9. Evaluation of a molecularly imprinted polymer for determination of steroids in goat milk by matrix solid phase dispersion.

    Gañán, Judith; Morante-Zarcero, Sonia; Gallego-Picó, Alejandrina; Garcinuño, Rosa María; Fernández-Hernando, Pilar; Sierra, Isabel


    A molecularly imprinted polymer-matrix solid-phase dispersion methodology for simultaneous determination of five steroids in goat milk samples was proposed. Factors affecting the extraction recovery such as sample/dispersant ratio and washing and elution solvents were investigated. The molecularly imprinted polymer used as dispersant in the matrix solid-phase dispersion procedure showed high affinity to steroids, and the obtained extracts were sufficiently cleaned to be directly analyzed. Analytical separation was performed by micellar electrokinetic chromatography using a capillary electrophoresis system equipped with a diode array detector. A background electrolyte composed of borate buffer (25mM, pH 9.3), sodium dodecyl sulfate (10mM) and acetonitrile (20%) was used. The developed MIP-MSPD methodology was applied for direct determination of testosterone (T), estrone (E1), 17β-estradiol (17β-E2), 17α-ethinylestradiol (EE2) and progesterone (P) in different goat milk samples. Mean recoveries obtained ranged from 81% to 110%, with relative standard deviations (RSD)≤12%. The molecularly imprinted polymer-matrix solid-phase dispersion method is fast, selective, cost-effective and environment-friendly compared with other pretreatment methods used for extraction of steroids in milk.

  10. A new solid polymer electrolyte incorporating Li10GeP2S12 into a polyethylene oxide matrix for all-solid-state lithium batteries

    Zhao, Yanran; Wu, Chuan; Peng, Gang; Chen, Xiaotian; Yao, Xiayin; Bai, Ying; Wu, Feng; Chen, Shaojie; Xu, Xiaoxiong


    Li10GeP2S12 (LGPS) is incorporated into polyethylene oxide (PEO) matrix to fabricate composite solid polymer electrolyte (SPE) membranes. The lithium ion conductivities of as-prepared composite membranes are evaluated, and the optimal composite membrane exhibits a maximum ionic conductivity of 1.21 × 10-3 S cm-1 at 80 °C and an electrochemical window of 0-5.7 V. The phase transition behaviors for electrolytes are characterized by DSC, and the possible reasons for their enhanced ionic conductivities are discussed. The LGPS microparticles, acting as active fillers incorporation into the PEO matrix, have a positive effect on the ionic conductivity, lithium ion transference number and electrochemical stabilities. In addition, two kinds of all-solid-state lithium batteries (LiFeO4/SPE/Li and LiCoO2/SPE/Li) are fabricated to demonstrate the good compatibility between this new SPE membrane and different electrodes. And the LiFePO4/Li battery exhibits fascinating electrochemical performance with high capacity retention (92.5% after 50 cycles at 60 °C) and attractive capacities of 158, 148, 138 and 99 mAh g-1 at current rates of 0.1 C, 0.2 C, 0.5 C and 1 C at 60 °C, respectively. It is demonstrated that this new composite SPE should be a promising electrolyte applied in solid state batteries based on lithium metal electrode.

  11. Surfactant-Free Solid Dispersions of Hydrophobic Drugs in an Amorphous Sugar Matrix Dried from an Organic Solvent.

    Takeda, Koji; Gotoda, Yuto; Hirota, Daichi; Hidaka, Fumihiro; Sato, Tomo; Matsuura, Tsutashi; Imanaka, Hiroyuki; Ishida, Naoyuki; Imamura, Koreyoshi


    The technique for homogeneously dispersing hydrophobic drugs in a water-soluble solid matrix (solid dispersion) is a subject that has been extensively investigated in the pharmaceutical industry. Herein, a novel technique for dispersing a solid, without the need to use a surfactant, is reported. A freeze-dried amorphous sugar sample was dissolved in an organic solvent, which contained a soluble model hydrophobic component. The suspension of the sugar and the model hydrophobic component was vacuum foam dried to give a solid powder. Four types of sugars and methanol were used as representative sugars and the organic medium. Four model drugs (indomethacin, ibuprofen, gliclazide, and nifedipine) were employed. Differential scanning calorimetry analyses indicated that the sugar and model drug (100:1) did not undergo segregation during the drying process. The dissolution of the hydrophobic drugs in water from the solid dispersion was then evaluated, and the results indicated that the Cmax and AUC0-60 min of the hydrophobic drug in water were increased when the surfactant-free solid dispersion was used. Palatinose and/or α-maltose were superior to the other tested carbohydrates in increasing Cmax and AUC0-60 min for all tested model drugs, and the model drug with a lower water solubility tended to exhibit a greater extent of over-dissolution.

  12. Determination of phenolic compounds in wines by novel matrix solid-phase dispersion extraction and gas chromatography/mass spectrometry.

    Minuti, Lucio; Pellegrino, Roberto


    A novel matrix solid-phase dispersion (MSPD) extraction method was developed to extract simultaneously 23 phenolic compounds from wine samples prior to determination by gas chromatography with mass spectrometric detection in the selected ion monitoring mode. Different parameters of the MSPD technique such as dispersant solid-phase, eluting solvent, and sample ionic strength and pH were optimized. The optimized MSPD procedure requires a small volume of wine (1 mL), commercial silica gel (1.5 g) as dispersant solid-phase and a small volume of ethyl acetate (5 mL) as eluting solvent. Under these conditions, the extraction of the studied compounds was almost complete (mean values of recoveries between 87 and 109%) in a short time (15 min). Moreover, satisfactory standard deviations of repeatability (RSD0.993) and detection limits (wines. Application was illustrated by analysis of different wine samples.

  13. Capacity Titration Technique for Determining the Solid Diffusion Coefficient of Intercalary Species within Insertion-host Materials

    Xin Cun TANG; Tian Duo LI


    In this paper, the capacity titration technique (CT technique) was developed on basis of the RPG (ratio of potentio-charge capacity to galvano-charge capacity) method to continuously determine the solid diffusion coefficient D of the intercalary species within insertion-host materials with a small voltage region. The linear equations of D vs. q (value of ratio of the potentio-charge capacity to the galvano-charge capacity) were given in different range of q. By the CT technique,the Li+ solid diffusion coefficients D within LiMn2O4 at different voltages were determined. The results showed that the values of D varied from 3.447× 10-9 cm2/s to 7.60× 10-11cm2/s in the voltage range of charge from 3.3V to 4.3V as a function of voltage with "W" shape.

  14. Leishmania amazonensis promastigotes in 3D Collagen I culture: an in vitro physiological environment for the study of extracellular matrix and host cell interactions

    Debora B. Petropolis


    Full Text Available Leishmania amazonensis is the causative agent of American cutaneous leishmaniasis, an important neglected tropical disease. Once Leishmania amazonensis is inoculated into the human host, promastigotes are exposed to the extracellular matrix (ECM of the dermis. However, little is known about the interaction between the ECM and Leishmania promastigotes. In this study we established L. amazonensis promastigote culture in a three-dimensional (3D environment mainly composed of Collagen I (COL I. This 3D culture recreates in vitro some aspects of the human host infection site, enabling the study of the interaction mechanisms of L. amazonensis with the host ECM. Promastigotes exhibited “freeze and run” migration in the 3D COL I matrix, which is completely different from the conventional in vitro swimming mode of migration. Moreover, L. amazonensis promastigotes were able to invade, migrate inside, and remodel the 3D COL I matrix. Promastigote trans-matrix invasion and the freeze and run migration mode were also observed when macrophages were present in the matrix. At least two classes of proteases, metallo- and cysteine proteases, are involved in the 3D COL I matrix degradation caused by Leishmania. Treatment with a mixture of protease inhibitors significantly reduced promastigote invasion and migration through this matrix. Together our results demonstrate that L. amazonensis promastigotes release proteases and actively remodel their 3D environment, facilitating their migration. This raises the possibility that promastigotes actively interact with their 3D environment during the search for their cellular “home”—macrophages. Supporting this hypothesis, promastigotes migrated faster than macrophages in a novel 3D co-culture model.


    AbstractFour tetrols of benzo[a]pyrene-DNA adducts were separated using reversed-phase high performance liquid chromatography. Chromatographic fractions containing a given tetrol were readily characterized with solid-matrix room temperature luminescence techniques. So...

  16. Evaluation of Iranian Leopold Matrix application in the Environmental Impact Assessment (EIA of solid waste management options in Birjand city

    S Valizadeh


    Full Text Available Background and Objective: Significant increase in population and as a result, the production of excessive waste has recently made attention to municipal solid waste management a necessary issue. The objective of this study was to use matrix-based EIA process in order to determine best waste management option in Birjand City and to suggest appropriate solutions to managers and planners of this city. Materials and Methods: Assessing the environmental impacts of waste management options was done using Iranian Leopold Matrix. Through this method, the environmental impacts of waste management options were determined in the Birjand City. The options were Open dumping, Recycling, Composting, and Sanitary damping. Results: The results indicated that Open dumping with a final score of -3.06 had the highest environmental impact and was introduced as the fourth preference. In addition, composting with final score of -2.34 has the lowest environmental impact compared with other options. Conclusion: About 76.95% of the composition of municipal solid waste of Birjand City is household waste; therefore, putrescible organic materials are the predominant waste. Thus, according to the results of the Iranian Leopold matrix method, composting option was introduced as the first priority and the most logical option for waste management in the Birjand City.

  17. A menthol-based solid dispersion technique for enhanced solubility and dissolution of sulfamethoxazole from an oral tablet matrix.

    Choonara, Bibi F; Choonara, Yahya E; Kumar, Pradeep; du Toit, Lisa C; Tomar, Lomas K; Tyagi, Charu; Pillay, Viness


    A menthol-based solid dispersion was designed to improve the intrinsic solubility of the poorly soluble sulfamethoxazole- a class II drug molecule of Biopharmaceutics Classification System (BCS) displaying widespread antibacterial activity. Solid dispersions of menthol and sulfamethoxazole were compressed with hydroxypropyl methylcellulose (HPMC) into suitable sulfamethoxazole-loaded matrix tablets for oral drug delivery. The sulfamethoxazole-loaded solid dispersions and compressed tablets were characterized for their physicochemical and physicomechanical properties such as changes in crystallinity, melting point, molecular transitions, and textural analysis for critical analysis of their effects on the solubility and dissolution of sulfamethoxazole. The formulations were further evaluated for swelling, degradation, solubility, and in vitro drug release behavior. In vitro drug release from the sulfamethoxazole-loaded matrix tablets displayed a minimum and maximum fractional release of 0.714 and 0.970, respectively. The tablets further displayed different release rate profiles over the study periods of 12, 16, 48, and 56 h which were attributed to the varying concentrations of menthol within each formulation. Menthol was determined as a suitable hydrophilic carrier for sulfamethoxazole since it functioned as a solubilizing and release-retarding agent for improving the solubility and dissolution of sulfamethoxazole as well as controlling the rate at which it was released.

  18. Effect of Host Medium on the Fluorescence Emission Intensity of Rhodamine B in Liquid and Solid Phase

    Fikry, M.; Omar, M. M.; Ismail, Lotfi Z.


    In this work, we study the effect of concentration, host medium, PH, ions complex and phase states on the fluorescence emission from the laser dye, Rhodamine B, pumping by UV laser as exited source. The polymethylmethacrylate PMMA used as host medium in case of solid phase samples while, ethanol and Tetrahydrofuran (THF) are used in case of liquid one. The Laser Induced Fluorescence (LIF) technique was used to study the fluorescence properties of the both cases liquid and thin film solid-state samples. In addition, the Dual Thermal Lens (DTL) technique was used to study the quantum yield of these samples. The maximum fluorescence emission observed at concentration of Rhodamine B C=3×10-4M. At this concentration of Rhodamine B, the type of solvent and polarity of the medium affect on the fluorescence emission intensity of Rhodamine B with. The measurements revile that, the behavior of both phases state was analogous and Rhodamine B/PMMA thin film sample by ratio of 4:1 and thickness 0.12 mm is the best photostability sample and its quantum yield about ≈ 0.82. Also, the fluorescence emission intensity of Rhodamine B was quenched by complex formation of Co, Al, Cu and iodide ions with Rhodamine B due to the increase of the charge density of the ions.

  19. Enhancing in vitro dissolution and in vivo bioavailability of fenofibrate by solid self-emulsifying matrix combined with SBA-15 mesoporous silica.

    Quan, Guilan; Wu, Qiaoli; Zhang, Xiaoxu; Zhan, Zhengwen; Zhou, Chan; Chen, Bao; Zhang, Zhengzan; Li, Ge; Pan, Xin; Wu, Chuanbin


    Mesoporous silica Santa Barbara amorphous-15 (SBA-15), derived from supermolecular assemblies of surfactant Pluronic(®) P123 with well-ordered 2-D hexagonal pores, was investigated as a reservoir to construct a novel solid self-emulsifying matrix for enhancing the oral bioavailability of fenofibrate (FNB). The emulsification rate and droplet size of a liquid self-emulsifying delivery system (SEDDS) were analyzed for optimization. SBA-15 was then added to the ethanol solution containing liquid SEDDS, and the obtained suspension changed into solid SEDDS matrix via solvent evaporation. The characterizations by SEM and XRD revealed that the solid matrix consisted of particles with smooth surface and FNB was completely transformed into molecular or amorphous state in the formulation. When introduced to aqueous media under gentle agitation, the solid matrix exhibited excellent self-emulsification properties and formed a uniform microemulsion with mean diameter of 117.35 ± 2.33 nm. The solid SEDDS matrix showed faster in vitro release rate than the raw powder and commercial capsule. The absorption of FNB delivered by solid SEDDS matrix was significantly improved in beagle dogs, and its Cmax and AUC values were about 8- and 4-fold greater than those of commercial products, respectively. In conclusion, SBA-15 emerged as a promising reservoir for SEDDS to enhance the bioavailability of poorly water-soluble drugs, which may provide a new strategy for advanced therapies. Copyright © 2016 Elsevier B.V. All rights reserved.

  20. A novel approach for the fabrication of all-inorganic nanocrystal solids: Semiconductor matrix encapsulated nanocrystal arrays

    Moroz, Pavel

    Growing fossil fuels consumption compels researchers to find new alternative pathways to produce energy. Along with new materials for the conversion of different types of energy into electricity innovative methods for efficient processing of energy sources are also introduced. The main criteria for the success of such materials and methods are the low cost and compelling performance. Among different types of materials semiconductor nanocrystals are considered as promising candidates for the role of the efficient and cheap absorbers for solar energy applications. In addition to the anticipated cost reduction, the integration of nanocrystals (NC) into device architectures is inspired by the possibility of tuning the energy of electrical charges in NCs via nanoparticle size. However, the stability of nanocrystals in photovoltaic devices is limited by the stability of organic ligands which passivate the surface of semiconductors to preserve quantum confinement. The present work introduces a new strategy for low-temperature processing of colloidal nanocrystals into all-inorganic films: semiconductor matrix encapsulated nanocrystal arrays (SMENA). This methodology goes beyond the traditional ligand-interlinking scheme and relies on the encapsulation of morphologically-defined nanocrystal arrays into a matrix of a wide-band gap semiconductor, which preserves optoelectronic properties of individual nanoparticles. Fabricated solids exhibit excellent thermal stability, which is attributed to the heteroepitaxial structure of nanocrystal-matrix interfaces. The main characteristics and properties of these solids were investigated and compared with ones of traditionally fabricated nanocrystal films using standard spectroscopic, optoelectronic and electronic techniques. As a proof of concept, we. We also characterized electron transport phenomena in different types of nanocrystal films using all-optical approach. By measuring excited carrier lifetimes in either ligand-linked or

  1. Rovibrational matrix elements of the multipole moments and of the polarizability of the H2 molecule in the solid phase: Effect of intermolecular potential

    Adya Prasad Mishra; T K Balasubramanian


    Rovibrational matrix elements of the multipole moments ℓ up to rank 10 and of the linear polarizability of the H2 molecule in the condensed phase have been computed taking into account the effect of the intermolecular potential. Comparison with gas phase matrix elements shows that the effect of solid state interactions is marginal.

  2. Modeling of transverse welds formation during liquid–solid extrusion directly following vacuum infiltration of magnesium matrix composite

    Jian Liu


    Full Text Available Liquid–solid extrusion directly following vacuum infiltration (LSEVI is an infiltration–extrusion integrated forming technique, and transverse weld between upper residual magnesium alloy and magnesium matrix composites is a common internal defect, which can severely reduce the yield of composite products. To improve current understanding on the mechanism of transverse welding phenomenon, a thermo-mechanical numerical model of LSEVI for magnesium matrix composites was developed. The formation of transverse weld during extrusion was visualized using finite element simulation method, and the formation mechanism was discussed from the aspect of velocity field using a point tracking technique. The simulation results were verified by the experimental results in term of weld shape.

  3. Polarizable continuum model study on the solvent effect of polymer matrix in poly(ethylene oxide)-based solid electrolyte.

    Eilmes, Andrzej; Kubisiak, Piotr


    The Polarizable Continuum Model has been used to study the effect of polymer matrix on Li (+) and Mg (2+) complexation in poly(ethylene oxide)-based solid electrolyte. Structures of complexes, stabilization energies, and vibrational frequencies are compared with corresponding vacuum values. The solvent effect of the polymer decreases with increasing cation coordination number. Optimized complex geometries do not differ significantly compared to vacuum calculations. Calculated shifts in vibrational frequencies depend on the complex structure; for hexacoordinated ion most frequencies are slightly red-shifted. The most important effect is the decrease of differences between relative stabilities of different structures in the solvent.

  4. Surfactant-free solid dispersion of fat-soluble flavour in an amorphous sugar matrix.

    Satoh, Tomo; Hidaka, Fumihiro; Miyake, Kento; Yoshiyama, Natsuki; Takeda, Koji; Matsuura, Tsutashi; Imanaka, Hiroyuki; Ishida, Naoyuki; Imamura, Koreyoshi


    A solid dispersion technique to homogeneously disperse hydrophobic ingredients in a water-soluble solid without using surfactant was examined as follows: first, freeze-dried amorphous sugar was dissolved in an organic medium that contained a soluble model hydrophobic component. Second, the mixed solution of sugar and the model hydrophobic component was vacuum dried into a solid (solid dispersion). Methanol and six fat-soluble flavours, including cinnamaldehyde, were used as organic media and model hydrophobic components. The retention of flavours in the solid dispersion during drying and storage under vacuum was evaluated. The amorphised disaccharides dissolved in methanol up to 100mg/mL, even temporarily (20s to 10 days) and could be solidified without any evidence of crystallisation and segregation from flavour. The solid dispersion, prepared using α-maltose usually showed 65-95% flavour retention during drying (and storage for cinnamaldehyde), whereas ⩾ 50% of the flavour was lost when the flavour was O/W emulsified with a surfactant and then freeze-dried with sugar.

  5. Very fast dissolving acid carboxymethylcellulose-rifampicin matrix: Development and solid-state characterization.

    Luciani-Giacobbe, Laura C; Ramírez-Rigo, María V; Garro-Linck, Yamila; Monti, Gustavo A; Manzo, Ruben H; Olivera, María E


    One of the main obstacles to the successful treatment of tuberculosis is the poor and variable oral bioavailability of rifampicin (RIF), which is mainly due to its low hydrophilicity and dissolution rate. The aim of this work was to obtain a hydrophilic new material that allows a very fast dissolution rate of RIF and therefore is potentially useful in the development of oral solid dosage forms. The acid form of carboxymethylcellulose (CMC) was co-processed with RIF by solvent impregnation to obtain CMC-RIF powder, which was characterized by polarized optical microscopy, powder x-ray diffraction, DSC-TGA, hot stage microscopy, (13)C and (15)N solid-state NMR and FT-IR spectroscopy. In addition, the CMC-RIF matrices were subjected to water uptake and dissolution studies to assess hydrophilicity and release kinetics. CMC-RIF is a crystalline solid dispersion. Solid-state characterization indicated that no ionic interaction occurred between the components, but RIF crystallized as a zwitterion over the surface of CMC, which drastically increased the hydrophilicity of the solid. The CMC-RIF matrices significantly improved the water uptake of RIF and disintegrated in a very short period immediately releasing RIF. As CMC improves the hydrophilicity and delivery properties of RIF, CMC-RIF is very useful in the design of oral solid dosage forms with very fast dissolution of RIF, either alone or in combination with other antitubercular drugs. Copyright © 2016 Elsevier B.V. All rights reserved.

  6. Solid dispersion matrix tablet comprising indomethacin-PEG-HPMC fabricated with fusion and mold technique

    Mesnukul A


    Full Text Available The purpose of this study is to fabricate the polyethylene glycol matrix tablet by mold technique. Indomethacin and hydroxypropylmethylcellulose were used as model drug and polymer, respectively, in PEG matrix system. The physical and drug release characteristics of developed matrix tablet were studied. This inert carrier system comprising 7:3 polyethylene glycol 4000: polyethylene glycol 400 could effectively enhance the solubility of indomethacin and an addition of hydroxypropylmethylcellulose could sustain the drug release. Scanning electron microscope photomicrograph indicated the drug diffusion outward through the porous network of this developed matrix tablet into the dissolution fluid. Least square fitting the experimental dissolution data to the mathematical expressions (power law, first-order, Higuchi′s and zero-order indicated the drug release kinetics primarily as Fickian diffusion. Both the enhancement of drug dissolution and the prolongation of the drug release could be achieved for aqueous insoluble drug such as, indomethacin, by using polyethylene glycol-hydroxypropylmethylcellulose matrix system prepared with melting and mold technique.

  7. Biofilms produced by Burkholderia cenocepacia: influence of media and solid supports on composition of matrix exopolysaccharides.

    Pellizzoni, Elena; Ravalico, Fabio; Scaini, Denis; Delneri, Ambra; Rizzo, Roberto; Cescutti, Paola


    Bacteria usually grow forming biofilms, which are communities of cells embedded in a self-produced dynamic polymeric matrix, characterized by a complex three-dimensional structure. The matrix holds cells together and above a surface, and eventually releases them, resulting in colonization of other surfaces. Although exopolysaccharides (EPOLs) are important components of the matrix, determination of their structure is usually performed on samples produced in non-biofilm conditions, or indirectly through genetic studies. Among the Burkholderia cepacia complex species, Burkholderia cenocepacia is an important pathogen in cystic fibrosis (CF) patients and is generally more aggressive than other species. In the present investigation, B. cenocepacia strain BTS2, a CF isolate, was grown in biofilm mode on glass slides and cellulose membranes, using five growth media, one of which mimics the nutritional content of CF sputum. The structure of the matrix EPOLs was determined by 1H-NMR spectroscopy, while visualization of the biofilms on glass slides was obtained by means of confocal laser microscopy, phase-contrast microscopy and atomic force microscopy. The results confirmed that the type of EPOLs biosynthesized depends both on the medium used and on the type of support, and showed that mucoid conditions do not always lead to significant biofilm production, while bacteria in a non-mucoid state can still form biofilm containing EPOLs.

  8. Role of constitutive behavior and tumor-host mechanical interactions in the state of stress and growth of solid tumors.

    Chrysovalantis Voutouri

    Full Text Available Mechanical forces play a crucial role in tumor patho-physiology. Compression of cancer cells inhibits their proliferation rate, induces apoptosis and enhances their invasive and metastatic potential. Additionally, compression of intratumor blood vessels reduces the supply of oxygen, nutrients and drugs, affecting tumor progression and treatment. Despite the great importance of the mechanical microenvironment to the pathology of cancer, there are limited studies for the constitutive modeling and the mechanical properties of tumors and on how these parameters affect tumor growth. Also, the contribution of the host tissue to the growth and state of stress of the tumor remains unclear. To this end, we performed unconfined compression experiments in two tumor types and found that the experimental stress-strain response is better fitted to an exponential constitutive equation compared to the widely used neo-Hookean and Blatz-Ko models. Subsequently, we incorporated the constitutive equations along with the corresponding values of the mechanical properties - calculated by the fit - to a biomechanical model of tumor growth. Interestingly, we found that the evolution of stress and the growth rate of the tumor are independent from the selection of the constitutive equation, but depend strongly on the mechanical interactions with the surrounding host tissue. Particularly, model predictions - in agreement with experimental studies - suggest that the stiffness of solid tumors should exceed a critical value compared with that of the surrounding tissue in order to be able to displace the tissue and grow in size. With the use of the model, we estimated this critical value to be on the order of 1.5. Our results suggest that the direct effect of solid stress on tumor growth involves not only the inhibitory effect of stress on cancer cell proliferation and the induction of apoptosis, but also the resistance of the surrounding tissue to tumor expansion.

  9. Solid-phase synthesis of succinylhydroxamate peptides : Functionalized matrix metalloproteinase inhibitors

    Leeuwenburgh, MA; Geurink, PP; Klein, T; Kauffman, HF; van der Marel, GA; Bischoff, R; Overkleeft, HS


    A novel solid-phase synthesis strategy toward succinylhydroxamate peptides, using an appropriately protected hydroxamate building block, is described. Rapid and efficient access is gained to amine-functionalized peptides, which can be decorated with, for instance, a fluorescent label. In addition, w

  10. Investigating the solid state hosting abilities of homo- and hetero-valent [Co7] metallocalix[6]arenes.

    Meally, Seán T; McDonald, Cecelia; Kealy, Patrick; Taylor, Stephanie M; Brechin, Euan K; Jones, Leigh F


    A family of homo-valent [Co(II)(7)(OH)(6)(L(1))(6)](NO(3))(2) (1), [(MeOH)(2) is a subset of Co(II)(7)(OH)(6)(L(1))(6)](NO(3))(2) (2) (where L(1)H = 2-iminomethyl-6-methoxyphenol) and hetero-valent [(NO(3))(2) is a subset of Co(III)Co(II)(6)(OH)(6)(L(2))(6)](NO(3))·3MeCN (4) (where L(2)H = 2-iminophenyl-6-methoxyphenol) complexes possess metallic skeletons describing planar hexagonal discs. Their organic exteriors form double-bowl shaped topologies, and coupled with their 3-D connectivity, this results in the formation of molecular cavities in the solid state. These confined spaces are shown to behave as host units in the solid state for guests including solvent molecules and charge balancing counter anions. Magnetic susceptibility measurements on 2 and 4 reveal weak ferro- and ferrimagnetism, respectively. The utilisation of other Co(II) salt precursors gives rise to entirely different species including the mononuclear and trinuclear complexes [Co(II)(L(2))(2)] (5) and [Co(III)(2)Na(I)(1)(L(3))(6)](BF(4)) (6) (where L(3)H = 2-iminomethyl-4-bromo-6-methoxyphenol).

  11. Evaluation of alternative environmentally friendly matrix solid phase dispersion solid supports for the simultaneous extraction of 15 pesticides of different chemical classes from drinking water treatment sludge.

    Soares, Karina Lotz; Cerqueira, Maristela Barnes Rodrigues; Caldas, Sergiane Souza; Primel, Ednei Gilberto


    This study describes the development, optimization and validation of a method for the extraction of 15 pesticides of different chemical classes in drinking water treatment sludge (DWTS) by vortex-assisted Matrix Solid Phase Dispersion (MSPD) with determination by gas chromatography coupled to mass spectrometry. It focused on the application of alternative and different solid supports to the extraction step of the MSPD. The main parameters that influenced the extraction were studied in order to obtain better recovery responses. Recoveries ranged from 70 to 120% with RSD below 20% for all analytes. Limits of quantification (LOQ) of the method ranged from 5 to 500 μg kg(-1) whereas the analytical curves showed correlation coefficients above 0.997. The method under investigation used low volume of solvent (5 mL), low sample mass (1.5 g) and low mass of chitin (0.5 g), an environmentally friendly support. It has advantages, such as speed, simplicity and low cost material, over other methods. When the method was applied, 4 out of 15 pesticides were detected in the DWTS samples in concentrations below the LOQ. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. Formation of Splats from Suspension Particles with Solid Inclusions Finely Dispersed in a Melted Metal Matrix

    Solonenko, O. P.


    A theoretical model has been developed to describe the splats formation from composite particles of several tens of micrometers in size whose liquid metal binder contains a high volume concentration of ultra-fine refractory solid inclusions uniformly distributed in the binder. A theoretical solution was derived, enabling evaluation of splat thickness and diameter, and also the contact temperature at the particle-substrate interface, under complete control of key physical parameters (KPPs) of the spray process (impact velocity, temperature, and size of the particle, and substrate temperature) versus the concentration of solid inclusions suspended in the metal-binder melt. Using the solution obtained, the calculations performed demonstrate the possibility of formulating adequate requirements on the KPPs of particle-substrate interaction providing a deposition of ceramic-metal coatings with predictable splat thickness and degree of particle flattening on the substrate, and also with desired contact temperature during the formation of the first coating monolayer.

  13. Adaptation response of Pseudomonas fragi on refrigerated solid matrix to a moderate electric field

    Chen, Wenbo; HU, HONGHAI; Zhang, Chunjiang; HUANG, Feng; Zhang, Dequan; Zhang, Hong


    Background Moderate electric field (MEF) technology is a promising food preservation strategy since it relies on physical properties—rather than chemical additives—to preserve solid cellular foods during storage. However, the effectiveness of long-term MEF exposure on the psychrotrophic microorganisms responsible for the food spoilage at cool temperatures remains unclear. Results The spoilage-associated psychrotroph Pseudomonas fragi MC16 was obtained from pork samples stored at 7 °C. Continu...

  14. Reduction in crystal symmetry of a solid solution: A neutron diffraction study at 15 K of the host/guest system asparagine/aspartic acid

    Weisinger-Lewin, Y.; Frolow, F.; Lahav, M.; Leiserowitz, L. (Weizmann Institute of Science, Rehovot (Israel)); McMullan, R.K.; Koetzle, T.F. (Brookhaven National Lab., Upton, NY (USA))


    It has been demonstrated, for the first time by diffraction methods, that a solid solution composed of host and guest molecules can exhibit a crystal symmetry lower than that of the host. The study proves that the symmetry of a solid solution is dependent not only upon the host crystal structure and the guest molecular structure but also upon the surface structure and symmetry of the host crystal. The crystal structures of (S)-asparagine monohydrate (D{sub 2}NCOCH{sub 2}CH(ND{sub 3})CO{sub 2} {times} D{sub 2}O) and of the solid solution (0.848:0.152) (S)-asparagine/(S)-aspartic acid (DO{sub 2}CCD{sub 2}CD(ND{sub 3})CO{sub 2}) monohydrate were refined by using neutron diffraction data obtained at 15 K. The space group of the pure host crystal is P2{sub 1}2{sub 1}2{sub 1} (Z = 4), whereas that of the host/guest crystal is monoclinic P12{sub 1}1 with two molecular sites per asymmetric unit. The ratios of guest/host occupancies of the two independent sites are 0.173:0.827 and 0.132:0.868. The reduction in symmetry is in accordance with the preferred adsorption of guest aspartic acid on the (010) crystal face at half of the orthorhombic, symmetry-related surface sites. Aspartic acid mimics, at the preferred (010) surface sites, molecular asparagine, participating in all hydrogen bonds. At the less-favored (010) surface sites a normal N-H{hor ellipsis}O(host) hydrogen bond is replaced by O(hydroxyl){hor ellipsis}O(host) repulsion between lone-pair electrons. 21 refs., 5 figs., 6 tabs.

  15. Solid Matrix Transformation and Tracer Addition using Molten Ammonium Bifluoride Salt as a Sample Preparation Method for Laser Ablation Inductively Coupled Plasma Mass Spectrometry

    Grate, Jay W.; Gonzalez, Jhanis J.; O' Hara, Matthew J.; Kellogg, Cynthia M.; Morrison, Samuel S.; Koppenaal, David W.; Chan, George C.; Mao, Xianglei; Zorba, Vassilia; Russo, Richard


    Laser ablation (LA) is a means of sample introduction to inductively coupled plasma (ICP) mass spectrometry (MS) that avoids acid dissolution and chemical separation steps conventionally associated with solid sample analysis. At the same time, certain features of LA-ICP-MS are often mentioned in critical reviews including solid matrix variability and its influence on the ablation process, matrix dependent elemental fractionation, lack of matrix matched standards for external calibration, and limitations to internal calibration because it is challenging to add and distribute spikes into solid samples. In this paper we introduce the concept of a synergistic minimal sample preparation method that is used in combination with LA-ICP-MS as a means to overcome these limitations. The aim of this minimal sample preparation procedure is to reactively transform the original matrix to a more consistent matrix for LA-based analysis, thus reducing the effects of matrix variability, while enabling the addition of tracers. In conjunction with ICP-MS, we call this MTR-LA-ICP-MS, where MTR is derived from matrix transformation including the option to add tracers

  16. Matrix solid-phase dispersion as a tool for phytochemical and bioactivities characterisation: Crataegus oxyacantha L._A case study.

    Benabderrahmane, Wassila; Lores, Marta; Lamas, Juan Pablo; Benayache, Samir


    The use of a matrix solid-phase dispersion (MSPD) process to extract polyphenols from hawthorn (Crataegus oxyacantha L.) a deciduous shrub with an expected rich phytochemical profile, has been evaluated. MSPD extracts of fruits and leaves have an outstanding content of polyphenols, although the particular phenolic profile is solvent dependent. The extracts were analysed by HPLC-DAD for the accurate identification of the major bioactive polyphenols, some of which have never been described for this species. MSPD has proven to be a good alternative to the classic methods of obtaining natural extracts, fast and with low consumption of organic solvents, therefore, environmentally friendly. The bioactivities can be considered also very remarkable, revealing extracts with high levels of antioxidant activity.

  17. Lipid nanoparticles with a solid matrix (SLN, NLC, LDC) for oral drug delivery.

    Muchow, Marc; Maincent, Philippe; Muller, Rainer H


    Solid lipid nanoparticles (SLN), nanostructured lipid carriers (NLC), and lipid-drug conjugates (LDC), commonly produced by high-pressure homogenization, are interesting vectors for oral delivery of lipophilic and, to a certain extent, hydrophilic substances. Their production can be done without the use of organic solvents. Techniques to make them a physically stable delivery system have been developed. Scaling up of the production process from lab-size to large-scale dimensions using high-pressure homogenization can be easily achieved by using a different type of homogenizer. The machines used for large-scale production often yield an even better product quality than the lab-scale types. This review article covers the methods of production, characterization, mechanisms of oral bioavailability enhancement, scale-up, final oral dosage forms, and regulatory aspects of lipid nanoparticles for oral drug delivery. It focuses mainly on high-pressure homogenization production methods.

  18. Optical limiting effect in a two-photon absorption dye doped solid matrix

    He, Guang S.; Bhawalkar, Jayant D.; Zhao, Chan F.; Prasad, Paras N.


    We recently reported a new lasing dye, trans-4-[p-(N-ethyl-N-hydroxylethylamino)styryl]-N-methylpyridinium tetraphenylborate (ASPT), which has also been shown to possess a strong two-photon absorption (TPA) and subsequent frequency upconversion fluorescence behavior when excited with near infrared laser radiation. Based on the TPA mechanism, a highly efficient optical limiting performance has been demonstrated in a 2 cm long ASPT-doped epoxy rod pumped with 1.06 μm Q-switched laser pulses at 50-250 MW/cm2 intensity levels. The measured nonlinear absorption coefficient reached 6 cm/GW for the tested sample of dopant concentration d0=4×10-3 M/L. The molecular TPA cross section of ASPT in the epoxy matrix is estimated as σ2=2.5×10-18 cm4/GW or σ2'=4.7×10-46 cm4/photon/s, respectively. Two-photon pumped cavity lasing is also observed in an ASPT-doped polymer rod.

  19. Matrix solid-phase dispersion and solid-phase microextraction applied to study the distribution of fenbutatin oxide in grapes and white wine.

    Montes, R; Canosa, P; Lamas, J Pablo; Piñeiro, A; Orriols, I; Cela, R; Rodríguez, I


    The fate of the acaricide fenbutatin oxide (FBTO) during the elaboration of white wine is evaluated. Matrix solid-phase dispersion (MSPD) and solid-phase microextraction (SPME) were used as sample preparation techniques applied to the semi-solid and the liquid matrices involved in this research, respectively. Selective determination of FBTO was achieved by gas chromatography with atomic emission detection (GC-AED). GC coupled to mass spectrometry was also used to establish the identity of FBTO by-products detected in must and wine samples. MSPD extractions were accomplished using C18 as dispersant and co-sorbent. Sugars and other polar interferences were first removed with water and water/acetone mixtures, then FBTO was recovered with 8 mL of acetone. When used in combination with GC-AED, the MSPD method provided limits of quantification (LOQs) in the low nanogram per gram range, recoveries around 90% and relative standard deviations below 13% for extractions performed in different days. Performance of SPME for must and wine was mainly controlled by the extraction temperature, time and fibre coating. Under final conditions, FBTO was extracted in the headspace mode for 45 min at 100 degrees C, using a 100 microm poly(dimethylsiloxane)-coated fibre. The achieved LOQs remained around or below 0.1 ng mL(-1), depending on the type of sample, and the inter-day precision ranged from 10% to 13%. FBTO residues in grapes stayed mostly on the skin of the fruit. Although FBTO was not removed during must and white wine elaboration, it remained associated with suspended particles existing in must and lees, settled after must fermentation, with a negligible risk of being transferred to commercialised wine. On the other hand, two by-products of FBTO (bis and mono (2-methyl-2-phenylpropyl) tin) were identified, for first time, in must and final white wines obtained from FBTO treated grapes. Found values for the first species ranged from 0.03 to 0.9 ng mL(-1).

  20. Adaptation response of Pseudomonas fragi on refrigerated solid matrix to a moderate electric field.

    Chen, Wenbo; Hu, Honghai; Zhang, Chunjiang; Huang, Feng; Zhang, Dequan; Zhang, Hong


    Moderate electric field (MEF) technology is a promising food preservation strategy since it relies on physical properties-rather than chemical additives-to preserve solid cellular foods during storage. However, the effectiveness of long-term MEF exposure on the psychrotrophic microorganisms responsible for the food spoilage at cool temperatures remains unclear. The spoilage-associated psychrotroph Pseudomonas fragi MC16 was obtained from pork samples stored at 7 °C. Continuous MEF treatment attenuated growth and resulted in subsequent adaptation of M16 cultured on nutrient agar plates at 7 °C, compared to the control cultures, as determined by biomass analysis and plating procedures. Moreover, intracellular dehydrogenase activity and ATP levels also indicated an initial effect of MEF treatment followed by cellular recovery, and extracellular β-galactosidase activity assays indicated no obvious changes in cell membrane permeability. Furthermore, microscopic observations using scanning and transmission electron microscopy revealed that MEF induced sublethal cellular injury during early treatment stages, but no notable changes in morphology or cytology on subsequent days. Our study provides direct evidence that psychrotrophic P. fragi MC16 cultured on nutrient agar plates at 7 °C are capable of adapting to MEF treatment.

  1. Solid Matrix Based Lipidic Nanoparticles in Oral Cancer Chemotherapy: Applications and Pharmacokinetics.

    Ahmad, Javed; Amin, Saima; Rahman, Mahfoozur; Rub, Rehan Abdur; Singhal, Madhur; Ahmad, Mohammad Zaki; Rahman, Ziyaur; Addo, Richard T; Ahmad, Farhan Jalees; Mushtaq, Gohar; Kamal, Mohammad Amjad; Akhter, Sohail


    Chemotherapeutic delivery by oral route in cancer patients has the potential to create "hospitalization free chemotherapy" which is a vision of oncologists, formulation scientists and patients. Such a therapeutic approach will improve patients' compliance, ease the burden of the patients' caregivers and significantly reduce the cost of treatment. In current clinical practice, chemotherapy carried out by intravenous injection or infusion leads to undesired side-effects such as plasma concentrations crossing the maximum safe concentration, rapid body clearance and lower bioavailability. Despite the presence of challenges such as poor aqueous solubility and stability of drugs and the presence of biological barriers like multidrug efflux transporter in the GI tract, oral cancer chemotherapy has the potential to surmount those obstacles. Lipid nanoparticles (LNPs) such as solid lipid nanoparticle, nanostructured lipid carriers, nano lipid-drug conjugates, mixed micelles, liposomes and nanoemulsions have shown some promising results for use in oral anticancer drug delivery through nanotechnological approach. LNPs demonstrate enhanced oral bioavailability owing to their ability to inhibit first pass metabolism via lymphatic absorption by chylomicron-linked and/or M-cell uptake. LNPs reduce the inter- and intrasubject pharmacokinetics variability of administrated drugs. Moreover, certain classes of phospholipids and surfactants used in the formulations of LNPs can suppress the P-glycoprotein efflux system. Here, we shall be discussing the biopharmaceutical challenges in oral cancer chemotherapy and how the LNPs may provide solutions to such challenges. The effect of GI tract environment on LNPs and pharmacokinetics shall also be discussed.

  2. Simultaneous determination of phenolic compounds in Equisetum palustre L. by ultra high performance liquid chromatography with tandem mass spectrometry combined with matrix solid-phase dispersion extraction.

    Wei, Zuofu; Pan, Youzhi; Li, Lu; Huang, Yuyang; Qi, Xiaolin; Luo, Meng; Zu, Yuangang; Fu, Yujie


    A method based on matrix solid-phase dispersion extraction followed by ultra high performance liquid chromatography with tandem mass spectrometry is presented for the extraction and determination of phenolic compounds in Equisetum palustre. This method combines the high efficiency of matrix solid-phase dispersion extraction and the rapidity, sensitivity, and accuracy of ultra high performance liquid chromatography with tandem mass spectrometry. The influential parameters of the matrix solid-phase dispersion extraction were investigated and optimized. The optimized conditions were as follows: silica gel was selected as dispersing sorbent, the ratio of silica gel to sample was selected to be 2:1 (400/200 mg), and 8 mL of 80% methanol was used as elution solvent. Furthermore, a fast and sensitive ultra high performance liquid chromatography with tandem mass spectrometry method was developed for the determination of nine phenolic compounds in E. palustre. This method was carried out within <6 min, and exhibited satisfactory linearity, precision, and recovery. Compared with ultrasound-assisted extraction, the proposed matrix solid-phase dispersion procedure possessed higher extraction efficiency, and was more convenient and time saving with reduced requirements on sample and solvent amounts. All these results suggest that the developed method represents an excellent alternative for the extraction and determination of active components in plant matrices.

  3. Solvent-controlled 2D host-guest (2,7,12-trihexyloxytruxene/coronene) molecular nanostructures at organic liquid/solid interface investigated by scanning tunneling microscopy.

    Liu, Jia; Zhang, Xu; Yan, Hui-Juan; Wang, Dong; Wang, Jie-Yu; Pei, Jian; Wan, Li-Jun


    The two-dimensional (2D) self-assembled networks of 2,7,12-trihexyloxytruxene (Tr) are shown to accommodate coronene guest molecules on highly oriented pyrolytic graphite (HOPG) surfaces. The host-guest structures are revealed by scanning tunneling microscopy (STM) at liquid/solid interfaces. The effect of solvents on the host-guest structures is intensively investigated in different solvents such as 1,2,4-trichlorobenzene (TCB), 1-phenyloctane, 1-octanol, and tetradecane. In contrast to the similar 2D hexagonal self-assembly of Tr host template on HOPG in different solvents, the formation of host-guest nanostructures of coronene in Tr 2D network strongly depend on the polarity of the solvents. The thermodynamic equilibrium during the host-guest assembly process is discussed, and the solvent-guest interaction is proposed as a main contributor for the observed solvent effect in the 2D host-guest self-assembly process. The results are significant to surface host-guest chemistry and nanopatterning.

  4. Utilization of chemically treated municipal solid waste (spent coffee bean powder) as reinforcement in cellulose matrix for packaging applications.

    Thiagamani, Senthil Muthu Kumar; Nagarajan, Rajini; Jawaid, Mohammad; Anumakonda, Varadarajulu; Siengchin, Suchart


    As the annual production of the solid waste generable in the form of spent coffee bean powder (SCBP) is over 6 million tons, its utilization in the generation of green energy, waste water treatment and as a filler in biocomposites is desirable. The objective of this article is to analyze the possibilities to valorize coffee bean powder as a filler in cellulose matrix. Cellulose matrix was dissolved in the relatively safer aqueous solution mixture (8% LiOH and 15% Urea) precooled to -12.5°C. To the cellulose solution (SCBP) was added in 5-25wt% and the composite films were prepared by regeneration method using ethyl alcohol as a coagulant. Some SCBP was treated with aq. 5% NaOH and the composite films were also prepared using alkali treated SCBP as a filler. The films of composites were uniform with brown in color. The cellulose/SCBP films without and with alkali treated SCBP were characterized by FTIR, XRD, optical and polarized optical microscopy, thermogravimetric analysis (TGA) and tensile tests. The maximum tensile strength of the composite films with alkali treated SCBP varied between (106-149MPa) and increased with SCBP content when compared to the composites with untreated SCBP. The thermal stability of the composite was higher at elevated temperatures when alkali treated SCBP was used. Based on the improved tensile properties and photo resistivity, the cellulose/SCBP composite films with alkali treated SCBP may be considered for packaging and wrapping of flowers and vegetables. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. Development of a poly(dimethylacrylamide) based matrix material for solid phase high density peptide array synthesis employing a laser based material transfer

    Ridder, Barbara; Foertsch, Tobias C.; Welle, Alexander; Mattes, Daniela S.; von Bojnicic-Kninski, Clemens M.; Loeffler, Felix F.; Nesterov-Mueller, Alexander; Meier, Michael A. R.; Breitling, Frank


    Poly(dimethylacrylamide) (PDMA) based matrix materials were developed for laser-based in situ solid phase peptide synthesis to produce high density arrays. In this specific array synthesis approach, amino acid derivatives are embedded into a matrix material, serving as a "solid" solvent material at room temperature. Then, a laser pulse transfers this mixture to the target position on a synthesis slide, where the peptide array is synthesized. Upon heating above the glass transition temperature of the matrix material, it softens, allowing diffusion of the amino acid derivatives to the synthesis surface and serving as a solvent for peptide bond formation. Here, we synthesized PDMA six-arm star polymers, offering the desired matrix material properties, using atom transfer radical polymerization. With the synthesized polymers as matrix material, we structured and synthesized arrays with combinatorial laser transfer. With densities of up to 20,000 peptide spots per cm2, the resolution could be increased compared to the commercially available standard matrix material. Time-of-Flight Secondary Ion Mass Spectrometry experiments revealed the penetration behavior of an amino acid derivative into the prepared acceptor synthesis surface and the effectiveness of the washing protocols.

  6. Matrix molecularly imprinted mesoporous sol-gel sorbent for efficient solid-phase extraction of chloramphenicol from milk.

    Samanidou, Victoria; Kehagia, Maria; Kabir, Abuzar; Furton, Kenneth G


    Highly selective and efficient chloramphenicol imprinted sol-gel silica based inorganic polymeric sorbent (sol-gel MIP) was synthesized via matrix imprinting approach for the extraction of chloramphenicol in milk. Chloramphenicol was used as the template molecule, 3-aminopropyltriethoxysilane (3-APTES) and triethoxyphenylsilane (TEPS) as the functional precursors, tetramethyl orthosilicate (TMOS) as the cross-linker, isopropanol as the solvent/porogen, and HCl as the sol-gel catalyst. Non-imprinted sol-gel polymer (sol-gel NIP) was synthesized under identical conditions in absence of template molecules for comparison purpose. Both synthesized materials were characterized by Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FT-IR) and nitrogen adsorption porosimetry, which unambiguously confirmed their significant structural and morphological differences. The synthesized MIP and NIP materials were evaluated as sorbents for molecularly imprinted solid phase extraction (MISPE) of chloramphenicol in milk. The effect of critical extraction parameters (flow rate, elution solvent, sample and eluent volume, selectivity coefficient, retention capacity) was studied in terms of retention and desorption of chloramphenicol. Competition and cross reactivity tests have proved that sol-gel MIP sorbent possesses significantly higher specific retention and enrichment capacity for chloramphenicol compared to its non-imprinted analogue. The maximum imprinting factor (IF) was found as 9.7, whereas the highest adsorption capacity of chloramphenicol by sol-gel MIP was 23 mg/g. The sol-gel MIP was found to be adequately selective towards chloramphenicol to provide the necessary minimum required performance limit (MRPL) of 0.3 μg/kg set forth by European Commission after analysis by LC-MS even without requiring time consuming solvent evaporation and sample reconstitution step, often considered as an integral part in solid phase extraction work-flow. Intra and

  7. Matrix solid phase dispersion assisted enzymatic hydrolysis as a novel approach for cocaine and opiates isolation from human hair.

    Míguez-Framil, Martha; Cabarcos, Pamela; Tabernero, María Jesús; Bermejo, Ana María; Bermejo-Barrera, Pilar; Moreda-Piñeiro, Antonio


    The possibility of assisting enzymatic hydrolysis (EH) procedures by sample disruption mechanisms inherent to matrix solid phase dispersion (MSPD) has been explored in the current study. EH of hair specimens from poly-drug abusers was assisted by dispersing/blending the sample (0.05 g) with alumina (2.25 g) before loading the dissolved enzyme (6 mL of 1 mg mL(-1) Pronase E in 1.4 M/1.4 M Tris/HCl, pH 7.3) through the hair-alumina solid phase packaged inside a disposable MSPD syringe. The MSPD-EH method was developed, and it proved to offer quantitative results when isolating cocaine, benzoylecgonine (BZE), codeine, morphine and 6-monoacethylmorphine (6-MAM) from human hair samples. The procedure allows an on column clean-up/pre-concentration procedure of the isolated targets by attaching a previously conditioned Oasis HLB cartridge to the end of the MSPD syringe. The EH procedure of human hair with Pronase E can therefore be shortened to approximately 30 min. Within this time, sample blending/dispersion, MSPD syringe package, elution (EH when dissolved Pronase E is passing through the sample-dispersant bed), and extract clean-up and target pre-concentration stages are achieved. Gas chromatography-mass spectrometry (GC-MS) was used for determining each target after elution from the Oasis HLB cartridges with 2 mL of 2% (v/v) acetic acid in methanol, concentration by N2 stream evaporation, and dried extract derivatization with N-methyl-tert-butylsilyltrifluoroacetamide (BSTFA) and chlorotrimethylsilane (TMCS). The method was validated according to the guidance for bioanalytical method validation of the US Department of Health and Human Services, Food and Drug Administration. The simplicity of the proposed approach makes it a useful procedure for screening/quantifying drugs of abuse in hair specimens from poly-drug abusers.

  8. Tilted Orientation of Photochromic Dyes with Guest-Host Effect of Liquid Crystalline Polymer Matrix for Electrical UV Sensing

    Amid Ranjkesh


    Full Text Available We propose a highly oriented photochromic dye film for an ultraviolet (UV-sensing layer, where spirooxazine (SO derivatives are aligned with the liquid crystalline UV-curable reactive mesogens (RM using a guest-host effect. For effective electrical UV sensing with a simple metal-insulator-metal structure, our results show that the UV-induced switchable dipole moment amount of the SO derivatives is high; however, their tilting orientation should be controlled. Compared to the dielectric layer with the nearly planar SO dye orientation, the photochromic dielectric layer with the moderately tilted dye orientation shows more than seven times higher the UV-induced capacitance variation.

  9. Tilted Orientation of Photochromic Dyes with Guest-Host Effect of Liquid Crystalline Polymer Matrix for Electrical UV Sensing.

    Ranjkesh, Amid; Park, Min-Kyu; Park, Do Hyuk; Park, Ji-Sub; Choi, Jun-Chan; Kim, Sung-Hoon; Kim, Hak-Rin


    We propose a highly oriented photochromic dye film for an ultraviolet (UV)-sensing layer, where spirooxazine (SO) derivatives are aligned with the liquid crystalline UV-curable reactive mesogens (RM) using a guest-host effect. For effective electrical UV sensing with a simple metal-insulator-metal structure, our results show that the UV-induced switchable dipole moment amount of the SO derivatives is high; however, their tilting orientation should be controlled. Compared to the dielectric layer with the nearly planar SO dye orientation, the photochromic dielectric layer with the moderately tilted dye orientation shows more than seven times higher the UV-induced capacitance variation.

  10. Evaluation of polycyclic aromatic hydrocarbons in asphalt binder using matrix solid-phase dispersion and gas chromatography.

    Fernandes, Paulo R N; Soares, Sandra de A; Nascimento, Ronaldo F; Soares, Jorge B; Cavalcante, Rivelino M


    A method developed for the extraction and analysis of polycyclic aromatic hydrocarbons (PAHs) in the asphalt binder using a matrix solid-phase dispersion (MSPD) and gas chromatography is presented. The MSPD method was proposed as a rapid and easy approach to determining PAHs present in the maltenic phase of asphalt binder extracted through a mechanical shaking and sonication of the material. The recovery rates ranged from 62.77-89.92% (shaking) and from 56.54-93.6% (sonication) with relative standard deviations lower than 8.8%. The study shows that the recovery rates using shaking and sonication extractions are not significantly different at the p asphalt binder from Brazil. The main PAHs found were BbF, BaP, Per, IncdP, DahA, and BghiP, with average concentrations of 10.2-20.7 mg/kg, but the PAHs Ace and Acy were not detected. However, Nap, Fl, Phen, Ant, Flr, Pyr, Chry, BaA, and BkF were present in average concentrations amounting to less than 10 mg/kg. The results showed that the MSPD method is potentially a valuable tool for the determination of PAHs in the asphalt binder.

  11. Analysis of four toxic metals in a single rice seed by matrix solid phase dispersion -inductively coupled plasma mass spectrometry

    He, Xiufen; Chen, Lixia; Chen, Xin; Yu, Huamei; Peng, Lixu; Han, Bingjun


    Toxic metals in rice pose great risks to human health. Metal bioaccumulation in rice grains is a criterion of breeding. Rice breeding requires a sensitive method to determine metal content in single rice grains to assist the variety selection. In the present study, four toxic metals of arsenic (As), cadmium (Cd), chromium (Cr) and lead (Pb) in a single rice grain were determined by a simple and rapid method. The developed method is based on matrix solid phase dispersion using multi-wall carbon nanotubes (MWCNTs) as dispersing agent and analyzed by inductively coupled plasma mass spectrometry. The experimental parameters were systematically investigated. The limits of detection (LOD) were 5.0, 0.6, 10 and 2.1 ng g‑1 for As, Cd, Cr, and Pb, respectively, with relative standard deviations (n = 6) of microwave digestion. The amount of sample required was reduced approximately 100 fold in comparison with the microwave digestion. The method has a high application potential for other sample matrices and elements with high sensitivity and sample throughput.

  12. Graphene nanoplatelets based matrix solid-phase dispersion microextraction for phenolic acids by ultrahigh performance liquid chromatography with electrochemical detection.

    Peng, Li-Qing; Yi, Ling; Yang, Qiu-Cheng; Cao, Jun; Du, Li-Jing; Zhang, Qi-Dong


    A simple, rapid and eco-friendly approach based on matrix solid-phase dispersion microextraction (MSPDM) followed by ultrahigh performance liquid chromatography coupled with electrochemical detection (UHPLC-ECD) was presented for the microextraction and determination of six phenolic acids in a plant preparation (Danshen tablets). The parameters that influenced the extraction performance of phenolic acids were investigated and optimized. The optimal MSPDM conditions were determined as follows: sorbent, using graphene nanoplatelets with sample/sorbent ratio of 1:1, grinding time set at 60 s, and 0.2 mL of water as elution solvent. Under the optimum conditions, the validation experiments indicated that the proposed method exhibited good linearity (r(2) ≥ 0.9991), excellent precision (RSD ≤ 4.57%), and satisfactory recoveries (82.34-98.34%). The limits of detection were from 1.19 to 4.62 ng/mL for six phenolic acids. Compared with other reported methods, this proposal required less sample, solvent and extraction time. Consequently, the proposed method was successfully used to the extraction and determination of phenolic acids in Danshen tablets.

  13. Novel dummy molecularly imprinted polymers for matrix solid-phase dispersion extraction of eight fluoroquinolones from fish samples.

    Sun, Xiaoli; Wang, Jincheng; Li, Yun; Yang, Jiajia; Jin, Jing; Shah, Syed Mazhar; Chen, Jiping


    A series of novel dummy molecularly imprinted polymers (DMIPs) were prepared as highly class-selective sorbents for fluoroquinolones. A non-poisonous dummy template, daidzein, was used for the first time to create specific molecular recognition sites for fluoroquinolones in the synthesized polymers. The influence of porogen polarity on dummy molecular imprinting effect was studied. The DMIP prepared using dimethylsulfoxide-acetonitrile (1:1.8, v/v) as porogen achieved the highest imprinting factors (IF) for fluoroquinolones over a range of IF 13.4-84.0. This DMIP was then used for selective extraction of eight fluoroquinolones (fleroxacin, ofloxacin, norfloxacin, pefloxacin, ciprofloxacin, lomefloxacin, enrofloxacin and gatifloxacin) from fish samples based on dummy molecularly imprinted matrix solid-phase dispersion (DMI-MSPD). The extracted fluoroquinolones were subsequently analyzed by high-performance liquid chromatography (HPLC) equipped with a fluorescence detector (FLD). The developed method had acceptable recoveries (64.4-102.7%) and precision (RSDs: 1.7-8.5%, n=5) for determination of fluoroquinolones in fish samples fortified at levels of 10 and 100ngg(-1). The limits of detection (LODs) for identification of eight fluoroquinolones ranged between 0.06 and 0.22ngg(-1). The results demonstrated great potential of the optimized method for sample preparation in routine analysis of trace fluoroquinolones in fish samples. Copyright © 2014 Elsevier B.V. All rights reserved.

  14. High-flexibility combinatorial peptide synthesis with laser-based transfer of monomers in solid matrix material.

    Loeffler, Felix F; Foertsch, Tobias C; Popov, Roman; Mattes, Daniela S; Schlageter, Martin; Sedlmayr, Martyna; Ridder, Barbara; Dang, Florian-Xuan; von Bojničić-Kninski, Clemens; Weber, Laura K; Fischer, Andrea; Greifenstein, Juliane; Bykovskaya, Valentina; Buliev, Ivan; Bischoff, F Ralf; Hahn, Lothar; Meier, Michael A R; Bräse, Stefan; Powell, Annie K; Balaban, Teodor Silviu; Breitling, Frank; Nesterov-Mueller, Alexander


    Laser writing is used to structure surfaces in many different ways in materials and life sciences. However, combinatorial patterning applications are still limited. Here we present a method for cost-efficient combinatorial synthesis of very-high-density peptide arrays with natural and synthetic monomers. A laser automatically transfers nanometre-thin solid material spots from different donor slides to an acceptor. Each donor bears a thin polymer film, embedding one type of monomer. Coupling occurs in a separate heating step, where the matrix becomes viscous and building blocks diffuse and couple to the acceptor surface. Furthermore, we can consecutively deposit two material layers of activation reagents and amino acids. Subsequent heat-induced mixing facilitates an in situ activation and coupling of the monomers. This allows us to incorporate building blocks with click chemistry compatibility or a large variety of commercially available non-activated, for example, posttranslationally modified building blocks into the array's peptides with >17,000 spots per cm(2).

  15. Metal-organic framework mixed-matrix disks: Versatile supports for automated solid-phase extraction prior to chromatographic separation.

    Ghani, Milad; Font Picó, Maria Francesca; Salehinia, Shima; Palomino Cabello, Carlos; Maya, Fernando; Berlier, Gloria; Saraji, Mohammad; Cerdà, Víctor; Turnes Palomino, Gemma


    We present for the first time the application of metal-organic framework (MOF) mixed-matrix disks (MMD) for the automated flow-through solid-phase extraction (SPE) of environmental pollutants. Zirconium terephthalate UiO-66 and UiO-66-NH2 MOFs with different size (90, 200 and 300nm) have been incorporated into mechanically stable polyvinylidene difluoride (PVDF) disks. The performance of the MOF-MMDs for automated SPE of seven substituted phenols prior to HPLC analysis has been evaluated using the sequential injection analysis technique. MOF-MMDs enabled the simultaneous extraction of phenols with the concomitant size exclusion of molecules of larger size. The best extraction performance was obtained using a MOF-MMD containing 90nm UiO-66-NH2 crystals. Using the selected MOF-MMD, detection limits ranging from 0.1 to 0.2μgL(-1) were obtained. Relative standard deviations ranged from 3.9 to 5.3% intra-day, and 4.7-5.7% inter-day. Membrane batch-to-batch reproducibility was from 5.2 to 6.4%. Three different groundwater samples were analyzed with the proposed method using MOF-MMDs, obtaining recoveries ranging from 90 to 98% for all tested analytes.

  16. High-flexibility combinatorial peptide synthesis with laser-based transfer of monomers in solid matrix material

    Loeffler, Felix F.; Foertsch, Tobias C.; Popov, Roman; Mattes, Daniela S.; Schlageter, Martin; Sedlmayr, Martyna; Ridder, Barbara; Dang, Florian-Xuan; von Bojničić-Kninski, Clemens; Weber, Laura K.; Fischer, Andrea; Greifenstein, Juliane; Bykovskaya, Valentina; Buliev, Ivan; Bischoff, F. Ralf; Hahn, Lothar; Meier, Michael A. R.; Bräse, Stefan; Powell, Annie K.; Balaban, Teodor Silviu; Breitling, Frank; Nesterov-Mueller, Alexander


    Laser writing is used to structure surfaces in many different ways in materials and life sciences. However, combinatorial patterning applications are still limited. Here we present a method for cost-efficient combinatorial synthesis of very-high-density peptide arrays with natural and synthetic monomers. A laser automatically transfers nanometre-thin solid material spots from different donor slides to an acceptor. Each donor bears a thin polymer film, embedding one type of monomer. Coupling occurs in a separate heating step, where the matrix becomes viscous and building blocks diffuse and couple to the acceptor surface. Furthermore, we can consecutively deposit two material layers of activation reagents and amino acids. Subsequent heat-induced mixing facilitates an in situ activation and coupling of the monomers. This allows us to incorporate building blocks with click chemistry compatibility or a large variety of commercially available non-activated, for example, posttranslationally modified building blocks into the array's peptides with >17,000 spots per cm2.

  17. Application of ionic liquids for elution of bioactive flavonoid glycosides from lime fruit by miniaturized matrix solid-phase dispersion.

    Xu, Jing-Jing; Yang, Rui; Ye, Li-Hong; Cao, Jun; Cao, Wan; Hu, Shuai-Shuai; Peng, Li-Qing


    In this work, two flavonoid glycosides (neohesperidin and naringin) in lime fruit were effectively extracted by miniaturized matrix solid phase dispersion (MSPD), followed by ultra-performance liquid chromatography-ultraviolet detection. The best results were obtained using Florisil (150mg) as the sorbent and 1-butyl-3-methylimidazolium tetrafluoroborate (0.4mL, 250mM) as the elution solvent. This work represents the first attempt of using ionic liquids as a green eluent for extraction of the investigated compounds in miniaturized MSPD. Compared with the conventional methods, the proposed method is advantageous due to improved enrichment factor and reduced reagent consumption. A good linearity was observed with r(2) values (>0.998). Meanwhile, the method gave acceptable recoveries (90.16-96.47%) for the determination of flavonoids in plant samples. The limits of detection of the two analytes ranged between 4.08 and 5.04μg/g. The results showed that the optimized method has a great potential for sample preparation in routine analysis of complex plant samples.

  18. Tissue-specific and SRSF1-dependent splicing of fibronectin, a matrix protein that controls host cell invasion

    Lopez-Mejia, Isabel Cristina; De Toledo, Marion; Della Seta, Flavio; Fafet, Patrick; Rebouissou, Cosette; Deleuze, Virginie; Blanchard, Jean Marie; Jorgensen, Christian; Tazi, Jamal; Vignais, Marie-Luce


    Cell invasion targets specific tissues in physiological placental implantation and pathological metastasis, which raises questions about how this process is controlled. We compare dermis and endometrium capacities to support trophoblast invasion, using matching sets of human primary fibroblasts in a coculture assay with human placental explants. Substituting endometrium, the natural trophoblast target, with dermis dramatically reduces trophoblast interstitial invasion. Our data reveal that endometrium expresses a higher rate of the fibronectin (FN) extra type III domain A+ (EDA+) splicing isoform, which displays stronger matrix incorporation capacity. We demonstrate that the high FN content of the endometrium matrix, and not specifically the EDA domain, supports trophoblast invasion by showing that forced incorporation of plasma FN (EDA–) promotes efficient trophoblast invasion. We further show that the serine/arginine-rich protein serine/arginine-rich splicing factor 1 (SRSF1) is more highly expressed in endometrium and, using RNA interference, that it is involved in the higher EDA exon inclusion rate in endometrium. Our data therefore show a mechanism by which tissues can be distinguished, for their capacity to support invasion, by their different rates of EDA inclusion, linked to their SRSF1 protein levels. In the broader context of cancer pathology, the results suggest that SRSF1 might play a central role not only in the tumor cells, but also in the surrounding stroma. PMID:23966470

  19. Matrix solid-phase dispersion coupled with homogeneous ionic liquid microextraction for the determination of sulfonamides in animal tissues using high-performance liquid chromatography.

    Wang, Zhibing; He, Mengyu; Jiang, Chunzhu; Zhang, Fengqing; Du, Shanshan; Feng, Wennan; Zhang, Hanqi


    Matrix solid-phase dispersion coupled with homogeneous ionic liquid microextraction was developed and applied to the extraction of some sulfonamides, including sulfamerazine, sulfamethazine, sulfathiazole, sulfachloropyridazine, sulfadoxine, sulfisoxazole, and sulfaphenazole, in animal tissues. High-performance liquid chromatography was applied to the separation and determination of the target analytes. The solid sample was directly treated by matrix solid-phase dispersion and the eluate obtained was treated by homogeneous ionic liquid microextraction. The ionic liquid was used as the extraction solvent in this method, which may result in the improvement of the recoveries of the target analytes. To avoid using organic solvent and reduce environmental pollution, water was used as the elution solvent of matrix solid-phase dispersion. The effects of the experimental parameters on recoveries, including the type and volume of ionic liquid, type of dispersant, ratio of sample to dispersant, pH value of elution solvent, volume of elution solvent, amount of salt in eluate, amount of ion-pairing agent (NH4 PF6 ), and centrifuging time, were evaluated. When the present method was applied to the analysis of animal tissues, the recoveries of the analytes ranged from 85.4 to 118.0%, and the relative standard deviations were lower than 9.30%. The detection limits for the analytes were 4.3-13.4 μg/kg.

  20. Matrix molecularly imprinted mesoporous sol–gel sorbent for efficient solid-phase extraction of chloramphenicol from milk

    Samanidou, Victoria, E-mail: [Laboratory of Analytical Chemistry, Department of Chemistry, Aristotle University of Thessaloniki (Greece); Kehagia, Maria [Laboratory of Analytical Chemistry, Department of Chemistry, Aristotle University of Thessaloniki (Greece); Kabir, Abuzar, E-mail: [International Forensic Research Institute, Department of Chemistry and Biochemistry, Florida International University, Miami, FL (United States); Furton, Kenneth G. [International Forensic Research Institute, Department of Chemistry and Biochemistry, Florida International University, Miami, FL (United States)


    Highly selective and efficient chloramphenicol imprinted sol–gel silica based inorganic polymeric sorbent (sol–gel MIP) was synthesized via matrix imprinting approach for the extraction of chloramphenicol in milk. Chloramphenicol was used as the template molecule, 3-aminopropyltriethoxysilane (3-APTES) and triethoxyphenylsilane (TEPS) as the functional precursors, tetramethyl orthosilicate (TMOS) as the cross-linker, isopropanol as the solvent/porogen, and HCl as the sol–gel catalyst. Non-imprinted sol–gel polymer (sol–gel NIP) was synthesized under identical conditions in absence of template molecules for comparison purpose. Both synthesized materials were characterized by Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FT-IR) and nitrogen adsorption porosimetry, which unambiguously confirmed their significant structural and morphological differences. The synthesized MIP and NIP materials were evaluated as sorbents for molecularly imprinted solid phase extraction (MISPE) of chloramphenicol in milk. The effect of critical extraction parameters (flow rate, elution solvent, sample and eluent volume, selectivity coefficient, retention capacity) was studied in terms of retention and desorption of chloramphenicol. Competition and cross reactivity tests have proved that sol–gel MIP sorbent possesses significantly higher specific retention and enrichment capacity for chloramphenicol compared to its non-imprinted analogue. The maximum imprinting factor (IF) was found as 9.7, whereas the highest adsorption capacity of chloramphenicol by sol–gel MIP was 23 mg/g. The sol–gel MIP was found to be adequately selective towards chloramphenicol to provide the necessary minimum required performance limit (MRPL) of 0.3 μg/kg set forth by European Commission after analysis by LC-MS even without requiring time consuming solvent evaporation and sample reconstitution step, often considered as an integral part in solid phase extraction work

  1. Determination of perfluorinated compounds in mollusks by matrix solid-phase dispersion and liquid chromatography-tandem mass spectrometry.

    Villaverde-de-Sáa, Eugenia; Quintana, José Benito; Rodil, Rosario; Ferrero-Refojos, Raúl; Rubí, Elisa; Cela, Rafael


    Perfluorinated compounds (PFCs) have been used for over 40 years in different commercial and industrial applications mainly as surfactants and surface protectors and have become an important class of marine emerging pollutants. This study presents the development and validation of a new analytical method to determine the simultaneous presence of eight PFCs in different kinds of mollusks using matrix solid-phase dispersion (MSPD) followed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Simplicity of the analytical procedure, low volume of solvent and quantity of sample required, low global price, and integration of extraction and clean-up into a single step, are the most important advantages of the developed methodology. Solvent, solid support (dispersing agent), clean-up sorbent, and their amounts were optimized by means of an experimental design. In the final method, 0.5 g of sample are dispersed with 0.2 g of diatomaceous earth and transferred into a polypropylene syringe containing 4 g of silica as clean-up sorbent. Then, analytes are eluted with 20 mL of acetonitrile. The extract is finally concentrated to a final volume of 0.5 mL in methanol, avoiding extract dryness in order to prevent evaporation losses and injected in the LC-MS/MS. The combination of this MSPD protocol with LC-MS/MS afforded detection limits from 0.05 to 0.3 ng g(-1). Also, a good linearity was established for the eight PFCs in the range from limit of quantification (LOQ) to 500 ng mL(-1) with R(2) > 0.9917. The recovery of the method was studied with three types of spiked mollusk and was in the 64-126% range. Moreover, a mussel sample was spiked and aged for more than 1 month and analyzed by the developed method and a reference method, ion-pair extraction, for comparison, producing both methods statistically equal concentration values. The method was finally applied to the determination of PFCs in different kinds of mollusks revealing concentrations up to 8.3 ng g(-1) for

  2. Vortex-homogenized matrix solid-phase dispersion for the extraction of short chain chlorinated paraffins from indoor dust samples.

    Chen, Yu-Hsuan; Chang, Chia-Yu; Ding, Wang-Hsien


    A simple and effective method for determining short chain chlorinated paraffins (SCCPs) in indoor dust is presented. The method employed a modified vortex-homogenized matrix solid-phase dispersion (VH-MSPD) prior to its detection by gas chromatography - electron-capture negative-ion mass spectrometry (GC-ECNI-MS) operating in the selected-ion-monitoring (SIM) mode. Under the best extraction conditions, 0.1-g of dust sample was dispersed with 0.1-g of silica gel by using vortex (2min) instead of using a mortar and pestle (3min). After that step, the blend was transferred to a glass column containing 3-g acidic silica gel, 2-g basic silica gel, and 2-g of deactivated silica gel, used as clean-up co-sorbents. Then, target analytes were eluted with 5mL of n-hexane/dichloromethane (2:1, v/v) mixture. The extract was evaporated to dryness under a gentle stream of nitrogen. The residue was then re-dissolved in n-hexane (10μL), and subjected to GC-ECNI-MS analysis. The limits of quantitation (LOQs) ranged from 0.06 to 0.25μg/g for each SCCP congener. Precision was less than 7% for both intra- and inter-day analysis. Trueness was above 89%, which was calculated by mean extraction recovery. The VH-MSPD combined with GC-ECNI-MS was successfully applied to quantitatively detect SCCPs from various indoor dust samples, and the concentrations ranged from 1.2 to 31.2μg/g. Copyright © 2016 Elsevier B.V. All rights reserved.

  3. Organ heterogeneity of host-derived matrix metalloproteinase expression and its involvement in multiple-organ metastasis by lung cancer cell lines.

    Shiraga, Minoru; Yano, Seiji; Yamamoto, Akihiko; Ogawa, Hirohisa; Goto, Hisatsugu; Miki, Toyokazu; Miki, Keisuke; Zhang, Helong; Sone, Saburo


    Cancer metastasis is tightly regulated by the interaction of tumor cells and host organ microenvironments. Matrix metalloproteinases (MMPs), produced by both tumor cells and host stromal cells, play a central role in tumor invasion and angiogenesis. We determined whether metastatic potential of lung cancer to multiple organs is dependent solely on the expression of MMPs by tumor cells, using two metastasis models of human lung cancer cell lines expressing various levels of MMPs and a MMP inhibitor (ONO-4817). In the lung metastasis model, tumor cells (PC14, PC14PE6, H226, A549) inoculated i.v. into nude or SCID mice metastasized only in the lung. In the multiple-organ metastasis model, tumor cells (RERF-LC-AI, SBC-3/DOX, H69/VP, which express low levels of MMPs) inoculated i.v. into natural killer cell-depleted SCID mice metastasized into the liver, kidneys, and systemic lymph nodes. Film in situ zymography analysis revealed that the nontumor parenchyma of the lung had no gelatinolytic activity, whereas gelatinolytic activity of the liver and kidney was high and low, respectively. In the lung metastasis model, gelatinolytic activity of lung nodules directly correlated with the in vitro expression of MMP-2 and MMP-9 by tumor cells. Inhibition of MMP activity by ONO-4817 suppressed lung metastasis by the cell lines that expressed MMPs, but not those that did not express MMP, via the inhibition of MMP activity of lung tumors. In the multiple-organ metastasis model, liver parenchyma, but not liver nodules, showed gelatinolytic activity. The MMP inhibition reduced metastasis to the liver, but not to the kidney or lymph nodes, via inhibition of MMP activity of liver parenchyma. These findings suggest that MMP expression varies among the host organ microenvironments and that stromal MMPs may promote metastasis of lung cancer. Therefore, antimetastatic effects based on MMP inhibition may be dependent on MMPs derived not only from tumor cells but also from organ

  4. Graphene-encapsulated silica as matrix solid-phase dispersion extraction sorbents for the analysis of poly-methoxylated flavonoids in the leaves of Murraya panaculata (L.) Jack.

    Sun, Ting; Li, Xuwen; Yang, Jie; Li, Lanjie; Jin, Yongri; Shi, Xiaolei


    In this study, graphene-encapsulated silica was synthesized by a hydrothermal reduction strategy. The presence of silica in graphene was identified by Fourier-transform infrared spectrometry, X-ray diffraction and scanning electron microscopy. The graphene-encapsulated silica subsequently was used as adsorbent for matrix solid-phase dispersion extraction of poly-methoxylated flavonoids from the dried leaves of Murraya panaculata (L.) Jack. Compared with the other adsorbents (graphene, silica gel, C18 silica, neutral alumina, diatomaceous earth) and without any adsorbents, better results were obtained. Then a method for analysis of poly-methoxylated flavonoids was established by coupling matrix solid-phase dispersion extraction with ultra high performance liquid chromatography and UV detection. Compared with reflux extraction and ultrasonic extraction, the proposed method is quicker, more efficient and more environmental protection. Less than 10 min is needed from extraction to detection.

  5. Behaviors of Oxide Layer at Interface between Semi-solid Filler Metal and Aluminum Matrix Composites during Vibration

    Lei Shi; Jiuchun Yan; Yanfei Han; Bo Peng


    The joint interface between semi-solid Zn-Al filler metal and SiCp/Al composites with applying vibration for different time was examined. With increasing vibrating time, the oxide layer was disrupted prior at the centre to the periphery of the interface. And the solid grains near the centre of interface in semi-solid filler metal aggregated into two solid regions and compressed the composites during vibration; the solid grains near the periphery of interface moved toward the edge and scraped the composites during vibration. The models of disrupting oxide layer under the vibration condition were developed. At the centre of interface, the oxide layer was tore and stripped during the solid grains in the semi-solid filler metal depressing the composites with a very high compressive stress. At the periphery of interface, the oxide layer was cut and stripped into the filler metal during the solid grains scraping the interface.

  6. Matrix Solid-Phase Dispersion Coupled with High-Performance Liquid Chromatography Diode Array Detection for Simultaneous Determination of Four Lipophilic Constituents from Salvia miltiorrhiza Bunge.

    Wang, Zhibing; Ma, Siyu; Zhang, Qian; He, Shuang; Li, Qing; Hu, Jianxue; Zhang, Hanqi


    A simple, rapid and efficient method based on matrix solid-phase dispersion coupled with high-performance liquid chromatography was developed for determination of lipophilic constituents, including dihydrotanshinone, tanshinone I, cryptotanshinone and tanshinone II A in Salvia miltiorrhiza Bunge Box-Behnken design was employed for optimization of the extraction conditions of matrix solid-phase dispersion, including mass ratio of dispersant to sample, volume of elution solvent, and amount of cleanup reagent. The optimal experimental results were obtained using 0.27 g of acid alumina as dispersant, 13 mL of acetonitrile as elution solvent and 0.36 g of acid alumina as cleanup reagent. The target analytes was determined by high-performance liquid chromatography. The recoveries of tanshinones obtained by analyzing the spiked samples were from 83.81% to 93.74% and relative standard deviations from 2.87% to 6.83%. Matrix solid-phase dispersion integrated the extraction and cleanup into a single step, which provides the advantages of being simple, fast and convenient. Compared with other conventional methods, the present method consumed less time and less organic solvent. The results demonstrate that this method has potential for the determination of active constituents and the quality control of traditional Chinese medicine.

  7. Spectroscopy of low-energy atoms released from a solid noble-gas matrix: Proposal for a trap-loading technique

    Lambo, R.; Rodegheri, C. C.; Silveira, D. M.; Cesar, C. L.


    We have studied the velocity distribution of chromium atoms released from a solid neon matrix at cryogenic temperatures via Doppler spectroscopy. The Ne matrix is grown by directing a small flux of gas onto a cold substrate, while Cr atoms are simultaneously implanted by laser ablation, with the resultant plume directed toward the growing matrix. The atoms are then released by a heat pulse. We have observed neutral Cr atoms at temperatures around 13K with densities close to 1012cm-3 . The released atoms have a large initial drift velocity, explained by simple kinetic theory arguments, due to the light species’ drag force. The scheme could be adapted to produce cryogenic beams of atoms, molecules, and possibly ions, for collisional studies and spectroscopy. However, our main motivation was the construction of a hydrogen trap, and here we discuss the prospects and problems of using this technique for this purpose.

  8. Investigation of the Matrix Effect on the Accuracy of Quantitative Analysis of Trace Metals in Liquids Using Laser-Induced Breakdown Spectroscopy with Solid Substrates.

    Xiu, Junshan; Dong, Lili; Qin, Hua; Liu, Yunyan; Yu, Jin


    The detection limit of trace metals in liquids has been improved greatly by laser-induced breakdown spectroscopy (LIBS) using solid substrate. A paper substrate and a metallic substrate were used as a solid substrate for the detection of trace metals in aqueous solutions and viscous liquids (lubricating oils) respectively. The matrix effect on quantitative analysis of trace metals in two types of liquids was investigated. For trace metals in aqueous solutions using paper substrate, the calibration curves established for pure solutions and mixed solutions samples presented large variation on both the slope and the intercept for the Cu, Cd, and Cr. The matrix effects among the different elements in mixed solutions were observed. However, good agreement was obtained between the measured and known values in real wastewater. For trace metals in lubricating oils, the matrix effect between the different oils is relatively small and reasonably negligible under the conditions of our experiment. A universal calibration curve can be established for trace metals in different types of oils. The two approaches are verified that it is possible to develop a feasible and sensitive method with accuracy results for rapid detection of trace metals in industrial wastewater and viscous liquids by laser-induced breakdown spectroscopy. © The Author(s) 2016.

  9. Thiourea-succinonitrile based polymer matrix for efficient and stable quasi solid state dye sensitized solar cells

    Grover, Rakhi; Jauhari, Himanshi; Saxena, Kanchan


    Dye sensitized solar cells (DSSCs) are considered to be emerging alternatives to the low cost indoor photovoltaic technologies. However, to make the application of these cells economically feasible, the stability of the cells need to be enhanced. This can be achieved by employing solid or quasi solid state electrolytes to reduce the leakage and sealing problems in DSSCs. In the present work, a gel state electrolyte composition was successfully prepared using thiourea and solid state ionic conductor succinonitrile along with other components. The composition has been used for the fabrication of quasi solid state DSSCs using Eosin B as the sensitizer material. The cells fabricated exhibited consistent photovoltaic properties even after 24 hours of storage under ambient conditions without sealing. The present work therefore, demonstrates a rapid and simple preparation of electrolyte medium for quasi solid state DSSCs.

  10. Molecular Characterization of the Multiple Interactions of SpsD, a Surface Protein from Staphylococcus pseudintermedius, with Host Extracellular Matrix Proteins.

    Giampiero Pietrocola

    Full Text Available Staphylococcus pseudintermedius, a commensal and pathogen of dogs and occasionally of humans, expresses surface proteins potentially involved in host colonization and pathogenesis. Here, we describe the cloning and characterization of SpsD, a surface protein of S. pseudintermedius reported as interacting with extracellular matrix proteins and corneocytes. A ligand screen and Western immunoblotting revealed that the N-terminal A domain of SpsD bound fibrinogen, fibronectin, elastin and cytokeratin 10. SpsD also interfered with thrombin-induced fibrinogen coagulation and blocked ADP-induced platelet aggregation. The binding site for SpsD was mapped to residues 395-411 in the fibrinogen γ-chain, while binding sites in fibronectin were localized to the N- and C-terminal regions. SpsD also bound to glycine- and serine-rich omega loops within the C-terminal tail region of cytokeratin 10. Ligand binding studies using SpsD variants lacking the C-terminal segment or containing an amino-acid substitution in the putative ligand binding site provided insights into interaction mechanism of SpsD with the different ligands. Together these data demonstrate the multi-ligand binding properties of SpsD and illustrate some interesting differences in the variety of ligands bound by SpsD and related proteins from S. aureus.

  11. LC/MS method using cloud point extraction for the determination of permitted and illegal food colors in liquid, semiliquid, and solid food matrixes: single-laboratory validation.

    Ates, Ebru; Mittendorf, Klaus; Senyuva, Hamide


    A cloud point extraction method is reported using LC/MS for the determination of regulated water-soluble food colors (Allura Red, Sunset Yellow, erythrosine, and tartrazine) and banned fat-soluble synthetic azo dyes (Sudan I, II, III, and IV; Red B; 7B; Black B; Red G; Metanil Yellow; and Rhodamine B). The extraction of all 14 colors was carried out with cloud point extraction using the nonionic surfactant Triton X 114. Optimized conditions for cloud point extraction were 3% Triton X 114 (w/v), 0.1 M ammonium acetate, and heating at 50 degrees C for 30 min. This approach proved effective in giving quantitative recoveries from a diverse range of food matrixes, and optimized LC gave baseline chromatographic separation for all colors including Sudan IV and Red B. Single-laboratory validation was performed with spiking into liquid matrixes (wine and homemade wine), semiliquid matrixes (sauce and homemade paprika paste), and solid matrixes (spice and homemade chili powder) using the respective blank matrixes for matrix-matched calibration. The LOQ values for water-soluble colors were in the range of 15-150 mg/kg, and for the fat-soluble colors, 0.1-1.5 mg/kg. The mean recovery values were in the range of 69.6-116.0% (except Allura Red and Sunset Yellow in wine, for which recoveries were lower). The mean RSDs for colors were in the range of 4.0-14.8%. A small survey was conducted of samples of confectionery products, dried fruits, wines, bitter sodas, juices, sauces, pastes, and spices, which demonstrated the applicability of the method to a diverse selection of real food samples. Allura Red was detected in strawberry jelly and Sunset Yellow in artificial saffron.

  12. Reproducibility of serum protein profiling by systematic assessment using solid-phase extraction and matrix-assisted laser desorption/ionization mass spectrometry

    Callesen, Anne K; Christensen, René Depont; Madsen, Jonna S


    for serum protein profiling we investigated a range of sample preparation techniques and developed a statistical method based on repeated analyses for evaluation of protein-profiling performance of MALDI MS. Two different solid-phase extraction (SPE) methods were investigated, namely custom......Protein profiling of human serum by matrix-assisted laser desorption/ionization mass spectrometry (MALDI MS) is potentially a new diagnostic tool for early detection of human diseases, including cancer. Sample preparation is a key issue in MALDI MS and the analysis of complex samples such as serum......-made microcolumns and commercially available magnetic beads. Using these two methods, nineteen different sample preparation methods for serum profiling by MALDI MS were systematically tested with regard to matrix selection, stationary phase, selectivity, and reproducibility. Microcolumns were tested with regard...

  13. A new and efficient Solid Phase Microextraction approach for analysis of high fat content food samples using a matrix-compatible coating.

    De Grazia, Selenia; Gionfriddo, Emanuela; Pawliszyn, Janusz


    The current work presents the optimization of a protocol enabling direct extraction of avocado samples by a new Solid Phase Microextraction matrix compatible coating. In order to further extend the coating life time, pre-desorption and post-desorption washing steps were optimized for solvent type, time, and degree of agitation employed. Using optimized conditions, lifetime profiles of the coating related to extraction of a group of analytes bearing different physical-chemical properties were obtained. Over 80 successive extractions were carried out to establish coating efficiency using PDMS/DVB 65µm commercial coating in comparison with the PDMS/DVB/PDMS. The PDMS/DVB coating was more prone to irreversible matrix attachment on its surface, with consequent reduction of its extractive performance after 80 consecutive extractions. Conversely, the PDMS/DVB/PDMS coating showed enhanced inertness towards matrix fouling due to its outer smooth PDMS layer. This work represents the first step towards the development of robust SPME methods for quantification of contaminants in avocado as well as other fatty-based matrices, with minimal sample pre-treatment prior to extraction. In addition, an evaluation of matrix components attachment on the coating surface and related artifacts created by desorption of the coating at high temperatures in the GC-injector port, has been performed by GCxGC-ToF/MS.

  14. Simultaneous determination of multiclass emerging contaminants in aquatic plants by ultrasound-assisted matrix solid-phase dispersion and GC-MS.

    Aznar, Ramón; Albero, Beatriz; Sánchez-Brunete, Consuelo; Miguel, Esther; Martín-Girela, Isabel; Tadeo, José L


    A multiresidue method was developed for the simultaneous determination of 31 emerging contaminants (pharmaceutical compounds, hormones, personal care products, biocides, and flame retardants) in aquatic plants. Analytes were extracted by ultrasound-assisted matrix solid-phase dispersion (UA-MSPD) and determined by gas chromatography-mass spectrometry after sylilation, The method was validated for different aquatic plants (Typha angustifolia, Arundo donax, and Lemna minor) and a semiaquatic cultivated plant (Oryza sativa) with good recoveries at concentrations of 100 and 25 ng g(-1) wet weight, ranging from 70 to 120 %, and low method detection limits (0.3 to 2.2 ng g(-1) wet weight). A significant difference of the chromatographic response was observed for some compounds in neat solvent versus matrix extracts, and therefore, quantification was carried out using matrix-matched standards in order to overcome this matrix effect. Aquatic plants taken from rivers located at three Spanish regions were analyzed, and the compounds detected were parabens, bisphenol A, benzophenone-3, cyfluthrin, and cypermethrin. The levels found ranged from 6 to 25 ng g(-1) wet weight except for cypermethrin that was detected at 235 ng g(-1) wet weight in O. sativa samples.

  15. Host-guest supramolecular chemistry at solid-liquid interface:An important strategy for preparing two-dimensional functional nanostructures

    ZHANG XueMei; ZENG QingDao; WANG Chen


    Supramolecular self-assembly,an important strategy in nanotechnology,has been widely studied in the past two decades.In this review,we have introduced the recent progress on construction of two-dimensional(2D)nanostructures by host-guest supramolecular chemistry at solid-liquid interface,and the interactions between the host assembly and the guest molecules are the major concerns.At first,the hydrogen bonds connected hybrid structures are discussed.And then we have paid a close attention on the surface-confined condensation reactions that has flourished recently in direct preparing novel nanostructures with increasing structural complexity.In the end,the cavity confinement of the 2D supramolecular host-guest architectures has been studied.On the basis of the above-mentioned interactions,a group of functional hybrid structures have been prepared.Notably,scanning tunneling microscopy(STM),a unique technique to probe the surface morphology and information at the single molecule level,has been used to probe the formed structures on highly oriented pyrolytic graphite(HOPG)surface.

  16. Recovery evaluation of organophosphorus pesticides from bee pollen by matrix solid-phase dispersion extraction using sorbents based on silica and titania

    Torres-Perea, C.; Muñoz-Rodríguez, D.; Medina-Peralta, S.; Carrera-Figueiras, C.; Moguel-Ordóñez, Y. B.


    This work focused on the evaluation of the recovery of organophosphorus pesticides from bee pollen after matrix solid phase-dispersion extraction (MSPD). Materials based on silica, titania and titania modified with polivylnylimidazole or polyestirene were used as adsorbents for the extraction of pesticides. Small amounts of fortified pollen (0.1 g, at 1 micro-g/g of pesticides), adsorbent (0.4 g) and solvent elution (1 mL de acetonitrile - ACN) were used in the extractions. For recovery evaluation, pollen extracts were analyzed by gas chromatography coupled with mass spectrometry.

  17. Simulation and Experimental on the Solvation Interaction between the GAP Matrix and Insensitive Energetic Plasticizers in Solid Propellants.

    Zhao, Yu; Zhang, Xiaohong; Zhang, Wei; Xu, Hongjun; Xie, Wuxi; Du, Jiaojiao; Liu, Yingzhe


    Multimethods of simulation and experiment have been performed to investigate the interaction between glycidyl azide polymer (GAP) matrix and insensitive energetic plasticizers N-butyl-N-(2-nitroxy-ethyl)nitramine (Bu-NENA) and bis(2,2-dinitropropyl)formal/acetal (BDNPF/A). To start with, the blending energy distribution and Huggins parameters have been calculated, indicating fine miscibility between the GAP matrix and both plasticizers. The solubility parameter and binding energies show better compatibility between Bu-NENA and the GAP matrix than BDNPF/A, owing to stronger interactions. The interaction mechanism includes both hydrogen bonds and van der Waals forces. The low field NMR physical cross-link density and dynamic rheological behaviors imply larger disentanglement effect of Bu-NENA in the GAP matrix. The dynamic mechanical performance of elastomers show lower glass transition temperature of GAP/Bu-NENA blends, as supportive proof of stronger interactions between the GAP matrix and Bu-NENA in comparison with BDNPF/A.

  18. Trypanosoma cruzi infection: a continuous invader-host cell cross talk with participation of extracellular matrix and adhesion and chemoattractant molecules

    Marino A.P.M.P.


    Full Text Available Several lines of evidence have shown that Trypanosoma cruzi interacts with host extracellular matrix (ECM components producing breakdown products that play an important role in parasite mobilization and infectivity. Parasite-released antigens also modulate ECM expression that could participate in cell-cell and/or cell-parasite interactions. Increased expression of ECM components has been described in the cardiac tissue of chronic chagasic patients and diverse target tissues including heart, thymus, central nervous system and skeletal muscle of experimentally T. cruzi-infected mice. ECM components may adsorb parasite antigens and cytokines that could contribute to the establishment and perpetuation of inflammation. Furthermore, T. cruzi-infected mammalian cells produce cytokines and chemokines that not only participate in the control of parasitism but also contribute to the establishment of chronic inflammatory lesions in several target tissues and most frequently lead to severe myocarditis. T. cruzi-driven cytokines and chemokines may also modulate VCAM-1 and ICAM-1 adhesion molecules on endothelial cells of target tissues and play a key role in cell recruitment, especially of activated VLA-4+LFA-1+CD8+ T lymphocytes, resulting in a predominance of this cell population in the inflamed heart, central nervous system and skeletal muscle. The VLA-4+-invading cells are surrounded by a fine network of fibronectin that could contribute to cell anchorage, activation and effector functions. Since persistent "danger signals" triggered by the parasite and its antigens are required for the establishment of inflammation and ECM alterations, therapeutic interventions that control parasitism and selectively modulate cell migration improve ECM abnormalities, paving the way for the development of new therapeutic strategies improving the prognosis of T. cruzi-infected individuals.

  19. IR spectrum of CH3CN-BF3 in solid neon: matrix effects on the structure of a Lewis acid-base complex.

    Eigner, Audrey A; Rohde, John A; Knutson, Christopher C; Phillips, James A


    We have observed several IR bands of CH3CN-BF3 in neon and nitrogen matrices. For the 11B isotopomer in neon matrices, we observed the BF3 symmetric deformation band (nu7) as a doublet at 600 and 603 cm(-1), the BF3 symmetric stretching band (nu6) as a doublet at 833 and 838 cm(-1), the BF3 asymmetric stretching mode (nu13) at 1281 cm(-1) (partially obscured), and the C-N stretching mode (nu2) as a doublet at 2352 and 2356 cm(-1). The nitrogen matrix data are largely consistent with those reported recently, though we do propose a refinement of one band assignment. Comparisons of the frequencies of a few key, structurally sensitive vibrational modes either observed in various condensed-phase environments or calculated for two minimum-energy gas-phase structures indicate that inert matrix media significantly alter the structural properties of CH3CN-BF3. Specifically, the B-N dative bond compresses relative to the gas phase and other concomitant changes occur as well. Furthermore, the frequency shifts depict structural changes that occur across the various matrix hosts in a manner that largely parallels the degree of stabilization offered by these inert media.

  20. In-line micro-matrix solid-phase dispersion extraction for simultaneous separation and extraction of Sudan dyes in different spices.

    Rajabi, Maryam; Sabzalian, Sedigheh; Barfi, Behruz; Arghavani-Beydokhti, Somayeh; Asghari, Alireza


    A novel, simple, fast, and miniaturized method, termed in-line micro-matrix solid-phase dispersion (in-line MMSPD), coupled with high performance liquid chromatography (HPLC) was developed for the simultaneous extraction and determination of Sudan dyes (i.e. Sudan I-IV, Sudan orange G, Sudan black B, and Sudan red G) with the aid of an experimental design strategy. In this method, a matrix solid-phase dispersion (MSPD) column including a suitable mixture of polar sorbents was inserted in the mobile phase pathway, and while the interfering compounds were retained, the analytes were eluted and entered into the analytical column. In this way, the extraction, elution, and separation of the analytes were performed sequentially. Under the optimal experimental conditions (including the amount of sample, 0.0426g; amount of dispersant phase, 0.0216g of florisil, 0.0227g of silica, 0.0141g of alumina; and blending time, 112s), the limits of detection (LODs), limits of quantification, linear dynamic ranges, and recoveries were obtained to be 0.3-15.3μgkg(-1), 1-50μgkg(-1), 50-28,000μgkg(-1), and 94.5-99.1%, respectively. The results obtained showed that determination of the selected Sudan dyes in food samples using an enough sensitive and a simple analytically validated method like in-line MMSPD may offer a suitable screening method, which could be useful for food analysis and adulteration.

  1. Research on Friction Property of WS2 Matrix Solid Lubricating Coatings%WS2基固体润滑涂层摩擦性能研究

    侯锁霞; 高辉; 贾晓鸣


    The tribological properties of WS2 matrix solid lubricating coating were investigated by friction and wear tests.The results show that,under normal temperature,the tribological coefficient of WS2 matrix solid lubricating coatings are close to that of MoS2 matrix solid lubricating coating,however,the coating quality of WS2 metal matrix is inferior to that of MoS2 ; under high temperature,WS2 matrix coatings have stable friction coefficient,the tribological properties of WS2 coatings are superior to MoS2 matrix solid lubricating coatings.The composite coatings including MoS2,WS2 and Sb2 O3 can play a better role in friction reducing and lubrication,and the friction coefficient can reach to 0.045 under high temperature of 400℃.For the composite coatings including MoS2,WS2 and Sb2 O3,Sb2 O3 reacts preferentially with the oxygen in the air under high temperature,which slows down the oxidation rate of MoS2 and WS2,and elevates the temperature that MoS2 and WS2 can withstand.In the condition of boundary lubrication,the mixed films of FeS and MoS2 are generated by the electrochemical catalysis and heat friction chemical reaction of MoS2,which improves the boundary lubrication.%通过摩擦磨损试验,研究WS2固体润滑剂的摩擦性能.结果表明:常温工况下,WS2固体润滑剂的摩擦因数与MoS2的相近,但WS2涂层在金属基上成膜状态不如MoS2涂层;高温工况下,WS2基涂层摩擦因数稳定,摩擦性能优于MoS2基固体润滑涂层;在400℃的温度条件下,WS2、MoS2、Sb2 O3复合涂层摩擦因数可达0.045,减摩润滑作用显著提高.在高温工况下,WS2、MoS2、Sb2O3复合涂层中Sb2O3优先与空气中的氧发生反应从而减缓MoS2、WS2的氧化速度,提高MoS2、WS2所能承受的温度;在边界润滑条件下,MoS2发生电化学催化和热摩擦化学反应,生成FeS和MoS2混合膜,改善了边界润滑.

  2. Molecularly designed lipid microdomains for solid dispersions using a polymer/inorganic carrier matrix produced by hot-melt extrusion.

    Adler, Camille; Schönenberger, Monica; Teleki, Alexandra; Kuentz, Martin


    Amorphous solid dispersions have for many years been a focus in oral formulations, especially in combination with a hot-melt extrusion process. The present work targets a novel approach with a system based on a fatty acid, a polymer and an inorganic carrier. It was intended to adsorb the acidic lipid by specific molecular interactions onto the solid carrier to design disorder in the alkyl chains of the lipid. Such designed lipid microdomains (DLM) were created as a new microstructure to accommodate a compound in a solid dispersion. Vibrational spectroscopy, X-ray powder diffraction, atomic force microscopy as well as electron microscopic imaging were employed to study a system of stearic acid, hydroxypropylcellulose and aluminum magnesium silicate. β-carotene was used as a poorly water-soluble model substance that is difficult to formulate with conventional solid dispersion formulations. The results indicated that the targeted molecular excipient interactions indeed led to DLMs for specific compositions. The different methods provided complementary aspects and important insights into the created microstructure. The novel delivery system appeared to be especially promising for the formulation of oral compounds that exhibit both high crystal energy and lipophilicity.

  3. The formation and physical stability of two-phase solid dispersion systems of indomethacin in supercooled molten mixtures with different matrix formers.

    Semjonov, Kristian; Kogermann, Karin; Laidmäe, Ivo; Antikainen, Osmo; Strachan, Clare J; Ehlers, Henrik; Yliruusi, Jouko; Heinämäki, Jyrki


    Amorphous solid dispersions (SDs) are a promising approach to improve the dissolution rate of and oral bioavailability of poorly water-soluble drugs. In some cases multi-phase, instead of single-phase, SD systems with amorphous drug are obtained. While it is widely assumed that one-phase amorphous systems are desirable, two-phase systems may still potentially exhibit enhanced stability and dissolution advantages over undispersed systems. The objective of the present study was to understand the solid-state properties of two-phase SDs with amorphous drug and their relation to physical stability. Two different types of excipients for SD formation were used, one being a polymer and the other a small molecule excipient. The supercooled molten SDs of a poorly water-soluble indomethacin (IND) with a graft copolymer, Soluplus® (SOL) and sugar alcohol, xylitol (XYL) were prepared. Supercooled molten SDs of IND with SOL were two-phase glassy suspension in which the amorphous drug was dispersed in an amorphous polymer matrix. A short-term aging of the SDs led to the formation of glassy suspensions where the crystalline drug was dispersed in an amorphous polymer matrix. These were physically stable at room temperature for the time period studied (RT, 23±2°C), but aging at high-humidity conditions (75% RH) recrystallization to metastable α-IND occurred. Interestingly, the SDs with XYL were two-phase amorphous precipitation systems in which the drug was in an amorphous form in the crystalline sugar alcohol matrix. The SDs of IND and XYL exhibited fast drug recrystallization. In conclusion, the preparation method of two-phase systems via co-melting in association with the rapid quench cooling is a feasible method for the formulation of poorly water-soluble drugs. The physical stability of these two-phase systems, however, is dependent on the carrier material and storage conditions.

  4. Vortex-assisted matrix solid-liquid dispersive microextraction for the analysis of triazole fungicides in cotton seed and honeysuckle by gas chromatography.

    Xue, Jiaying; Li, Huichen; Liu, Fengmao; Jiang, Wenqing; Hou, Fan


    A one-step analytical method termed vortex-assisted matrix solid-liquid dispersive microextraction (VA-MSLDME) was developed for the determination of seven triazole fungicides from cotton seed and honeysuckle prior to gas chromatography with electron capture detection. The VA-MSLDME was performed by mixing the matrix, primary secondary amine, acetonitrile, toluene, and water in one single system. The target fungicides in the sample were extracted, cleaned up and preconcentrated simultaneously in the matrix/acetonitrile/water/toluene system. Meanwhile, the interferences were adsorbed by the cleanup adsorbent. The extraction recoveries of the fungicides from the samples varied from 82.9% to 97.8% with relative standard deviations of 4.4-8.5%. The enrichment factors of the analytes ranged from 22 to 47, and the limits of detection were in the range of 0.05-20 μg/kg. The results demonstrated the significant predominance of VA-MSLDME in the analysis of pesticide residues in cotton seed and honeysuckle samples.

  5. Micro-matrix solid-phase dispersion coupled with MEEKC for quantitative analysis of lignans in Schisandrae Chinensis Fructus using molecular sieve TS-1 as a sorbent.

    Chu, Chu; Wei, Mengmeng; Wang, Shan; Zheng, Liqiong; He, Zheng; Cao, Jun; Yan, Jizhong


    A simple and effective method was developed for determining lignans in Schisandrae Chinensis Fructus by using a micro-matrix solid phase dispersion (MSPD) technique coupled with microemulsion electrokinetic chromatography (MEEKC). Molecular sieve, TS-1, was applied as a solid supporting material in micro MSPD extraction for the first time. Parameters that affect extraction efficiency, such as type of dispersant, mass ratio of the sample to the dispersant, grinding time, elution solvent and volume were optimized. The optimal extraction conditions involve dispersing 25mg of powdered Schisandrae samples with 50mg of TS-1 by a mortar and pestle. A grinding time of 150s was adopted. The blend was then transferred to a solid-phase extraction cartridge and the target analytes were eluted with 500μL of methanol. Moreover, several parameters affecting MEEKC separation were studied, including the type of oil, SDS concentration, type and concentration of cosurfactant, and concentration of organic modifier. A satisfactory linearity (R>0.9998) was obtained, and the calculated limits of quantitation were less than 2.77μg/mL. Finally, the micro MSPD-MEEKC method was successfully applied to the analysis of lignans in complex Schisandrae fructus samples. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. C-Cl activation by group IV metal oxides in solid argon matrixes: matrix isolation infrared spectroscopy and theoretical investigations of the reactions of MOx (M = Ti, Zr; x = 1, 2) with CH3Cl.

    Zhao, Yanying


    Reactions of the ground-state titanium and zirconium monoxide and dioxide molecules with monochloromethane in excess argon matrixes have been investigated in solid argon by infrared absorption spectroscopy and density functional theoretical calculations. The results show that the ground-state MOx (M = Ti, Zr; x = 1, 2) molecules react with CH3Cl to first form the weakly bound MO(CH3Cl) and MO2(CH3Cl) complexes. The MO(CH3Cl) complexes can rearrange to the CH3M(O)Cl isomers with the Cl atom of CH3Cl coordination to the metal center of MO upon UV light irradiation (λ MOx mechanism was interpreted by the calculated potential energy profiles.

  7. Matrix effect on the performance of headspace solid phase microextraction method for the analysis of target volatile organic compounds (VOCs) in environmental samples.

    Higashikawa, Fábio S; Cayuela, Maria Luz; Roig, Asunción; Silva, Carlos A; Sánchez-Monedero, Miguel A


    Solid phase microextraction (SPME) is a fast, cheap and solvent free methodology widely used for environmental analysis. A SPME methodology has been optimized for the analysis of VOCs in a range of matrices covering different soils of varying textures, organic matrices from manures and composts from different origins, and biochars. The performance of the technique was compared for the different matrices spiked with a multicomponent VOC mixture, selected to cover different VOC groups of environmental relevance (ketone, terpene, alcohol, aliphatic hydrocarbons and alkylbenzenes). VOC recovery was dependent on the nature itself of the VOC and the matrix characteristics. The SPME analysis of non-polar compounds, such as alkylbenzenes, terpenes and aliphatic hydrocarbons, was markedly affected by the type of matrix as a consequence of the competition for the adsorption sites in the SPME fiber. These non-polar compounds were strongly retained in the biochar surfaces limiting the use of SPME for this type of matrices. However, this adsorption capacity was not evident when biochar had undergone a weathering/aging process through composting. Polar compounds (alcohol and ketone) showed a similar behavior in all matrices, as a consequence of the hydrophilic characteristics, affected by water content in the matrix. SPME showed a good performance for soils and organic matrices especially for non-polar compounds, achieving a limit of detection (LD) and limit of quantification (LQ) of 0.02 and 0.03 ng g(-1) for non-polar compounds and poor extraction for more hydrophilic and polar compounds (LD and LQ higher 310 and 490 ng g(-1)). The characteristics of the matrix, especially pH and organic matter, had a marked impact on SPME, due to the competition of the analytes for active sites in the fiber, but VOC biodegradation should not be discarded in matrices with active microbial biomass.

  8. Chiral discrimination in host-guest supramolecular complexes. Understanding enantioselectivity and solid solution behaviors by using spectroscopic methods and chemical sensors.

    Grandeury, Arnaud; Condamine, Eric; Hilfert, Liane; Gouhier, Géraldine; Petit, Samuel; Coquerel, Gérard


    Diastereomeric host-guest associations formed between permethylated-beta-cyclodextrin (TMbeta-Cd) and the two enantiomers of p-bromophenylethanol (pBrPE) were characterized in aqueous solution by NMR spectroscopy, revealing similar inclusion geometries and weak binding constants, whatever the guest configuration. These features were confirmed by hydrogenation experiments, and do not allow to account for the ability of TMbeta-Cd to resolve racemic pBrPE by successive crystallizations [Grandeury, A.; Petit, S.; Gouhier, G.; Agasse, V.; Coquerel, G. Tetrahedron: Asymmetry 2003, 14, 2143-2152]. The analysis, by means of solid-state NMR, oxidation experiments, and solubility measurements, of the two crystalline phases containing known proportions of guest enantiomers revealed identical inclusion geometries in a given phase, irrespective of the enantiomeric composition. The corresponding solid solutions were further characterized by the determination of an isothermal section (40 degrees C) in the relevant ternary phase diagram. It appears from all these data that chiral resolution mechanisms in this system can only be envisaged in terms of nucleation conditions of each crystal form (with its specific inclusion geometry) and enantiomeric recognition at crystal solution interfaces during the growth of each crystal packing.

  9. Current state of knowledge when it comes to consumer exposure to nanomaterial embedded in a solid matrix

    Mackevica, Aiga; Hansen, Steffen Foss


    Little is known about consumer exposure to engineered nanomaterials (ENMs) stemming from NM-containing consumer products. Here, we focus especially on studies that have investigated the release of ENMs from consumer products, investigating to what extent the information in the open literature can......, we summarized the studies by identifying nanomaterial(s), product name, product type, Product or Article Category according to REACH; experimental setup, total content in product, information on release, techniques used for characterization of nanomaterials both in product matrix and in the released...

  10. Strong work-hardening behavior induced by the solid solution strengthening of dendrites in TiZr-based bulk metallic glass matrix composites

    Ma, D.Q. [State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004 (China); Jiao, W.T. [College of Education, Hebei Normal University of Science and Technology, Qinhuangdao 066004 (China); Zhang, Y.F. [State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004 (China); Hebei Vocational and Technical College of Building Materials, Qinhuangdao 066004 (China); Wang, B.A.; Li, J.; Zhang, X.Y. [State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004 (China); Ma, M.Z., E-mail: [State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004 (China); Liu, R.P. [State Key Laboratory of Metastable Materials Science and Technology, Yanshan University, Qinhuangdao 066004 (China)


    Highlights: • Hardness of dendrite of TiZr-based BMGMCs increases. • Strong work-hardening behavior is obtained after solid solution strengthening. • Lattice distortions of dendrite suffering from rapid cooling are detected. - Abstract: A series of TiZr-based bulk metallic glass matrix composites (BMGMCs) with distinguished mechanical properties are successfully fabricated by adding different volume fractions of Ta (Ti{sub 38.8}Zr{sub 28.8}Cu{sub 6.2}Be{sub 16.2}Nb{sub 10} as the basic composition, denoted as Ta{sub 0.0}–Ta{sub 8.0}). Along with the growth of precipitated phase, typical dendritic morphology is fully developed in the TiZr-based BMGMCs of Ta{sub 8.0}. Energy-dispersive spectrometry analysis of the dendrites and glass matrix indicates that the metallic elements of Nb and Ta should preferentially form solid solution into dendrites. The chaotic structure of high-temperature precipitate phase is trapped down by the rapid cooling of the copper-mould. The detected lattice distortions in the dendrites are attributed to the strong solid solution strengthening of the metallic elements of Ti, Zr, Nb, and Ta. These lattice distortions increase the resistance of the dislocation motion and pin the dislocations, thus the strength and hardness of dendrite increase. Dendrites create a strong barrier for the shear band propagation and generate multiple shear bands after solid solution strengthening, thereby providing the TiZr-based BMGMCs with greatly improved capacity to sustain plastic deformation and resistance to brittle fracture. Thus, the TiZr-based BMGMCs possess distinguished work-hardening capability. Among these TiZr-based BMGMCs, the sample Ta{sub 0.5} possesses the largest plastic strain (ε{sub p}) at 20.3% and ultimate strength (σ{sub max}) of 2613 MPa during compressive loading. In addition, the sample of Ta{sub 0.5} exhibits work-hardening up to an ultrahigh tensile strength of 1680 MPa during the tensile process, and then progressively

  11. Serum protein profiling by miniaturized solid-phase extraction and matrix-assisted laser desorption/ionization mass spectrometry

    Callesen, Anne K; Mohammed, Shabaz; Bunkenborg, Jakob;


    for translation of MALDI-MS based diagnostic methods to clinical applications. We have investigated a number of MALDI matrices and several miniaturized solid-phase extraction (SPE) methods for serum protein concentration and desalting with the aim of generating reproducible, high-quality protein profiles by MALDI...... mass spectra (m/z 1000-12,000) to be obtained from serum. In a proof-of-principle application, SPE with chelating material and MALDI-MS identified protein peaks in serum that had been previously reported for distinguishing a person diagnosed with breast cancer from a control. These preliminary results...

  12. Electrical field assisted matrix solid phase dispersion as a powerful tool to improve the extraction efficiency and clean-up of fluoroquinolones in bovine milk.

    da Silva, Mariana Cristina; Orlando, Ricardo Mathias; Faria, Adriana Ferreira


    This work presents a new method by electrical matrix solid phase dispersion for the extraction and clean-up of marbofloxacin, ofloxacin, norfloxacin, ciprofloxacin, enrofloxacin, difloxacin and sarafloxacin in bovine milk. Composition and pH of the eluent, applied electrical potential and polarity were optimized by experimental designs. The combination of the chromatographic and electrophoretic mechanisms allowed the extraction and clean-up in one step with low organic solvent consumption, high extraction throughput and elution automation. Linearity, precision, trueness and limit of quantification were evaluated and provided values in accordance with other methods recently developed for the analysis of fluoroquinolones in milk. This technique proved to be promising for the extraction and clean-up of ionizable analytes in different milk matrices. Copyright © 2016 Elsevier B.V. All rights reserved.

  13. Tracer aroma compound transfer from a solid and complex-flavored food matrix packed in treated papers or plastic packaging film.

    Dury-Brun, Cécile; Lequin, Sonia; Chalier, Pascale; Desobry, Stéphane; Voilley, Andrée


    The objective of this work was to study the transfer of four aroma compounds (ethyl butyrate, ethyl hexanoate, cis-3-hexenol, and benzaldehyde) from a solid and complex-flavored food matrix (sponge cake) toward and through packaging films placed in indirect contact during storage in accelerated aging conditions (38 degrees C and 86% relative humidity gradient). The efficiency of treated papers relative to that of standard paper and plastic as barrier was tested. Before storage, aroma compound volatility in the sponge cake was measured, and similar values were found between aroma compounds, due to the fat content of the sponge cake. Whatever the aroma compound, permeability values during storage were similar for the same packaging film. The plastic film was the highest barrier, whereas calendering and coating treatments applied to treated papers decreased effectively their permeability. An opposite trend was observed for aroma compound sorption into packaging films during storage.

  14. Rotational States of Methyl Radical Monitored by EPR Line Shape of Matrix-Isolated CH3 in CO2 and N2O Solids

    Dmitriev, Yu. A.; Melnikov, V. D.; Zelenetckii, I. A.; Benetis, N. P.


    Methyl radicals, CH3, were trapped in matrices of solid CO2 and N2O by condensing the methyl along with the matrix constituents from the gas phase. The obtained EPR spectra were analyzed using EasySpin and/ or SimFonia simulation software and ab-initio computed quantum-chemistry parameters. We focus on two distinguished features of the spectra: the temperature-dependent linewidth anisotropy and the origin of the weak satellite doublets. The low-temperature spectral analysis of the satellites was based on the coupled representation of the three proton spins of CH3 and a recently obtained parameterization of the spin Hamiltonian based on one nuclear quartet and two doublets within the D3 group. These features were closely correlated to the state of rotation of the trapped radical.

  15. Application of matrix solid-phase dispersion followed by GC-MS/MS to the analysis of emerging contaminants in vegetables.

    Albero, Beatriz; Sánchez-Brunete, Consuelo; Miguel, Esther; Tadeo, José L


    A multiresidue method for the determination of 17 emerging contaminants in vegetables was developed based on ultrasound-assisted matrix solid-phase dispersion (MSPD). The analysis was performed using isotope dilution gas chromatography tandem mass spectrometry. In the development of the MSPD procedure, different parameters such as sonication and the type of sorbent or extraction solvent were assayed. Manual and in situ derivatization was assayed and the chromatographic response was higher when the reaction takes place in the injection port. The limits of detection obtained for the studied compounds were in the range of 0.1-0.4ngg(-1) for the different vegetables analyzed. The developed method was applied to vegetables obtained from several local markets. At least one of the organophosphates was detected in the analyzed samples at levels ranging from 0.6 to 4.6ngg(-1) and bisphenol A was detected in all the samples at concentration up to 16ngg(-1).

  16. Determination of the major constituents in fruit of Arctium lappa L. by matrix solid-phase dispersion extraction coupled with HPLC separation and fluorescence detection.

    Liu, He; Zhang, Yupu; Sun, Yantao; Wang, Xue; Zhai, Yujuan; Sun, Ye; Sun, Shuo; Yu, Aimin; Zhang, Hanqi; Wang, Yinghua


    The arctiin and arctigenin in the fruit of Arctium lappa L. were extracted by matrix solid-phase dispersion (MSPD) and determined by high-performance liquid chromatography (HPLC) with fluorescence detection. The experimental conditions for the MSPD were optimized. Silica gel was selected as dispersion adsorbent and methanol as elution solvent. The calibration curve showed good relationship (r>0.9998) in the concentration range of 0.010-5.0μgmL(-1) for arctiin and 0.025-7.5μgmL(-1) for arctigenin. The recoveries were between 74.4% and 100%. The proposed method consumed less sample, time and solvent compared with conventional methods, including ultrasonic and Soxhlet extraction.

  17. New method based on combining ultrasonic assisted miniaturized matrix solid-phase dispersion and homogeneous liquid-liquid extraction for the determination of some organochlorinated pesticides in fish

    Rezaei, Farahnaz [Department of Analytical Chemistry, Faculty of Chemistry, Iran University of Science and Technology, Narmak, Tehran 16846 (Iran, Islamic Republic of); Hosseini, Mohammad-Reza Milani, E-mail: [Department of Analytical Chemistry, Faculty of Chemistry, Iran University of Science and Technology, Narmak, Tehran 16846 (Iran, Islamic Republic of); Electroanalytical Chemistry Research Center, Iran University of Science and Technology, Narmak, Tehran 16846 (Iran, Islamic Republic of)


    Highlights: {yields} Ultrasonic assisted miniaturized matrix solid-phase dispersion combined with HLLE was developed as a new method for the extraction of OCPs in fish. {yields} The goal of this combination was to enhance the selectivity of HLLE procedure and to extend its application in biological samples. {yields} This method proposed the advantages of good detection limits, lower consumption of reagents, and does not need any special instrumentation. - Abstract: In this study, ultrasonic assisted miniaturized matrix solid-phase dispersion (US-MMSPD) combined with homogeneous liquid-liquid extraction (HLLE) has been developed as a new method for the extraction of organochlorinated pesticides (OCPs) in fish prior to gas chromatography with electron capture detector (GC-ECD). In the proposed method, OCPs (heptachlor, aldrin, DDE, DDD, lindane and endrin) were first extracted from fish sample into acetonitrile by US-MMSPD procedure, and the extract was then used as consolute solvent in HLLE process. Optimal condition for US-MMSPD step was as follows: volume of acetonitrile, 1.5 mL; temperature of ultrasound, 40 deg. C; time of ultrasound, 10 min. For HLLE step, optimal results were obtained at the following conditions: volume of chloroform, 35 {mu}L; volume of aqueous phase, 1.5 mL; volume of double distilled water, 0.5 mL; time of centrifuge, 10 min. Under the optimum conditions, the enrichment factors for the studied compounds were obtained in the range of 185-240, and the overall recoveries were ranged from 39.1% to 81.5%. The limits of detection were 0.4-1.2 ng g{sup -1} and the relative standard deviations for 20 ng g{sup -1} of the OCPs, varied from 3.2% to 8% (n = 4). Finally, the proposed method has been successfully applied to the analysis of the OCPs in real fish sample, and satisfactory results were obtained.

  18. A Solid Binding Matrix/Mimic Receptor-Based Sensor System for Trace Level Determination of Iron Using Potential Measurements

    Ayman H. Kamel


    Full Text Available Iron(II-(1,10-phenanthroline complex imprinted membrane was prepared by ionic imprinting technology. In the first step, Fe(II established a coordination linkage with 1,10-phenanthroline and functional monomer 2-vinylpyridine (2-VP. Next, the complex was copolymerized with ethylene glycol dimethacrylate (EGDMA as a crosslinker in the presence of benzoyl peroxide (BPO as an initiator. Potentiometric chemical sensors were designed by dispersing the iron(II-imprinted polymer particles in 2-nitrophenyloctyl ether (o-NPOE plasticizer and then embedded in poly vinyl chloride (PVC matrix. The sensors showed a Nernstian response for [Fe(phen3]2+ with limit of detection 3.15 ng mL−1 and a Nernstian slope of 35.7 mV per decade.

  19. Density matrix treatment of combined instantaneous and delayed dissipation for an electronically excited adsorbate on a solid surface

    Leathers, Andrew S.; Micha, David A.; Kilin, Dmitri S.


    The interaction of an excited adsorbate with a medium undergoing electronic and vibrational transitions leads to fast dissipation due to electronic energy relaxation and slow (or delayed) dissipation from vibrational energy relaxation. A theoretical and computational treatment of these phenomena has been done in terms of a reduced density matrix satisfying a generalized Liouville-von Neumann equation, with instantaneous dissipation constructed from state-to-state transition rates, and delayed dissipation given by a memory term derived from the time-correlation function (TCF) of atomic displacements in the medium. Two representative applications are presented here, where electronic excitation may enhance vibrational relaxation of an adsorbate. They involve femtosecond excitation of (a) a CO molecule adsorbed on the Cu(001) metal surface and (b) a metal cluster on a semiconductor surface, Ag3Si(111):H, both electronically excited by visible light and undergoing electron transfer and dissipative dynamics by electronic and vibrational relaxations. Models have been parametrized in both cases from electronic structure calculations and known TCFs for the medium, which are slowly decaying in case (a) and fast decaying in case (b). This requires different numerical procedures in the solution of the integrodifferential equations for the reduced density matrix, which have been solved with an extension of the Runge-Kutta algorithm. Results for the populations of vibronic states versus time show that they oscillate due to vibrational coupling through dissipative interaction with the substrate and show quantum coherence. The total population of electronic states is, however, little affected by vibrational motions. Vibrational relaxation is important only at very long times to establish thermal equilibrium.

  20. Development of surface imprinted core-shell nanoparticles and their application in a solid-phase dispersion extraction matrix for methyl parathion.

    Tan, Lei; Li, Weiming; Li, He; Tang, Youwen


    Applying molecular imprinting techniques to the surface of functionalized SiO2 allows the preparation of molecularly imprinted polymers (MIPs) with accessible, high affinity and surface exposed binding sites. This paper demonstrates a new strategy for producing such hybrid organic-inorganic surface imprinted silica nanoparticles for specific recognition of methyl parathion. The technique provides surface grafting imprinting in chloroform using amino modified silica nanoparticles as supports, acrylamide as the functional monomer, γ-methacryloxypropyl trimethoxy silane as the grafting agent, and methyl parathion as a template. The amino propyl functional monomer layer directs the selective occurrence of imprinting polymerization at the silica surface through copolymerization of grafting agents with functional monomers, but also acts as an assistive monomer to drive the template into the formed polymer shells to create effective recognition sites. The resulting MIPs-SiO2 nanoparticles display three-dimensional core-shell architectures and large surface areas. The molecularly imprinted shell provides recognition sites for methyl parathion, with the materials exhibiting excellent performance for selecting the template. Using MIPs-SiO2 nanoparticles as a matrix of solid-phase dispersion extraction sorbents, trace amounts of methyl parathion are selectivity extracted from pear and green vegetable samples while simultaneously eliminating matrix interferences, attaining recoveries of 84.7-94.4% for the samples.

  1. Matrix effect on leaching of Bisphenol A diglycidyl ether (BADGE) from epoxy resin based inner lacquer of aluminium tubes into semi-solid dosage forms.

    Lipke, Uwe; Haverkamp, Jan Boris; Zapf, Thomas; Lipperheide, Cornelia


    To study the impact of different semi-solid dosage form components on the leaching of Bisphenol A (BPA) and Bisphenol A diglycidyl ether (BADGE) from the epoxy resin-based inner lacquer of aluminium tubes, the tubes were filled with different matrix preparations and stored at an elevated temperature. Despite compliance with the European Standards EN 15348 and EN 15766 on porosity and polymerisation of internal coatings of aluminium tubes, the commercially available tubes used in the study contained an increased amount of polymerisation residues, such as unbound BPA, BADGE and BADGE derivatives in the lacquer, as determined by acetonitrile extraction. Storage of Macrogol ointments in these tubes resulted in an almost quantitative migration of the unbound polymerisation residues from the coating into the ointment. In addition, due to alterations observed in the RP-HPLC chromatograms of the matrix spiked with BADGE and BADGE derivatives it is supposed that the leachates can react with formulation components. The contamination of the medicinal product by BPA, BADGE and BADGE derivatives can be precluded by using aluminium tubes with an internal lacquer with a low degree of unbound polymerisation residues. Copyright © 2015 The Authors. Published by Elsevier B.V. All rights reserved.

  2. Synbeads porous-rigid methacrylic support: application to solid phase peptide synthesis and characterization of the polymeric matrix by FTIR microspectroscopy and high resolution magic angle spinning NMR.

    Sinigoi, Loris; Bravin, Paola; Ebert, Cynthia; D'Amelio, Nicola; Vaccari, Lisa; Ciccarelli, Laura; Cantone, Sara; Basso, Alessandra; Gardossi, Lucia


    Porous and rigid methacrylic Synbeads were optimized and applied efficiently to the solid phase peptide synthesis with the objective of improving significantly volumetric yields (0.33 mol/L calculated on the basis of maximum chemical accessibility, i.e. the maximum number of functional groups that can be acylated by FmocCl) as compared to swelling commercial polymers (from 0.06 to 0.12 mol/L). The effects of the density of functional groups and spacer length were investigated obtaining a chemical accessibility of the functional groups up to 1 mmol/g(dry). High resolution magic angle spinning (HR-MAS) was exploited to evidence the presence of "solution-like" flexible linkers anchored on the rigid methacrylic backbone of Synbeads and to study the degree of functionalization by the Wang linker. To demonstrate the efficiency of the optimized Synbeads, the peptides Somatostatin and Terlipressin were synthesized. In the case of Somatostatin, final synthetic yields of 45 and 60% were achieved by following the HCTU/DIPEA and DIC/HOBt routes respectively, with the HPLC purity always higher than 83%. In the case of Terlipressin, the synthesis was carried out in parallel on Synbeads and also on TentaGel, ChemMatrix, and PS-DVB for comparison (DIC/HOBt route). The profiles describing the synthetic efficiency demonstrated that Synbeads leads to synthetic efficiency (86%) comparable to PS-DVB (96%) or ChemMatrix (84%). In order to gain a more precise picture of chemical and morphological features of Synbeads, their matrix was also characterized by exploiting innovative approaches based on FTIR microspectroscopy with a conventional source and with synchrotron radiation. A uniform distribution of the functional groups was evidenced through a detailed chemical mapping.

  3. Stromal matrix metalloprotease-13 knockout alters Collagen I structure at the tumor-host interface and increases lung metastasis of C57BL/6 syngeneic E0771 mammary tumor cells.

    Perry, Seth W; Schueckler, Jill M; Burke, Kathleen; Arcuri, Giuseppe L; Brown, Edward B


    Matrix metalloproteases and collagen are key participants in breast cancer, but their precise roles in cancer etiology and progression remain unclear. MMP13 helps regulate collagen structure and has been ascribed largely harmful roles in cancer, but some studies demonstrate that MMP13 may also protect against tumor pathology. Other studies indicate that collagen's organizational patterns at the breast tumor-host interface influence metastatic potential. Therefore we investigated how MMP13 modulates collagen I, a principal collagen subtype in breast tissue, and affects tumor pathology and metastasis in a mouse model of breast cancer. Tumors were implanted into murine mammary tissues, and their growth analyzed in Wildtype and MMP13 KO mice. Following extraction, tumors were analyzed for collagen I levels and collagen I macro- and micro-structural properties at the tumor-host boundary using immunocytochemistry and two-photon and second harmonic generation microscopy. Lungs were analyzed for metastases counts, to correlate collagen I changes with a clinically significant functional parameter. Statistical analyses were performed by t-test, analysis of variance, or Wilcoxon-Mann-Whitney tests as appropriate. We found that genetic ablation of host stromal MMP13 led to: 1. Increased mammary tumor collagen I content, 2. Marked changes in collagen I spatial organization, and 3. Altered collagen I microstructure at the tumor-host boundary, as well as 4. Increased metastasis from the primary mammary tumor to lungs. These results implicate host MMP13 as a key regulator of collagen I structure and metastasis in mammary tumors, thus making it an attractive potential therapeutic target by which we might alter metastatic potential, one of the chief determinants of clinical outcome in breast cancer. In addition to identifying stromal MMP13 is an important regulator of the tumor microenvironment and metastasis, these results also suggest that stromal MMP13 may protect against breast

  4. Determination of N,N-dimethyltryptamine in Mimosa tenuiflora inner barks by matrix solid-phase dispersion procedure and GC-MS.

    Gaujac, Alain; Aquino, Adriano; Navickiene, Sandro; de Andrade, Jailson Bittencourt


    N,N-dimethyltryptamine (DMT) is a potent hallucinogen found in beverages consumed in religion rituals and neo-shamanic practices over the world. Two of these religions, Santo Daime and União do Vegetal (UDV), are represented in countries including Australia, the United States and several European nations. In some of this countries there have been legal disputes concerning the legalization of ayahuasca consumption during religious rituals, a beverage rich in DMT. In Brazil, even children and pregnant women are legally authorized to consume ayahuasca in a religious context. A simple and low-cost method based on matrix solid-phase dispersion (MSPD) and gas chromatography with mass spectrometric detection (GC-MS) has been optimized for the determination of N,N-dimethyltryptamine in Mimosa tenuiflora inner bark. The experimental variables that affect the MSPD method, such as the amounts of solid-phase and herbal sample, solvent nature, eluate volume and NaOH concentration were optimized using an experimental design. The method showed good linearity (r = 0.9962) and repeatability (RSD < 7.4%) for DMT compound, with detection limit of 0.12 mg/g. The proposed method was used to analyze 24 samples obtained locally. The results showed that concentrations of the target compound in M. tenuiflora barks, ranged from 1.26 to 9.35 mg/g for these samples. Copyright © 2011 Elsevier B.V. All rights reserved.

  5. EPR spectrum of the Y@C82 metallofullerene isolated in solid argon matrix: hyperfine structure from EPR spectroscopy and relativistic DFT calculations.

    Misochko, Eugenii Ya; Akimov, Alexander V; Belov, Vasilii A; Tyurin, Daniil A; Bubnov, Vyacheslav P; Kareev, Ivan E; Yagubskii, Eduard B


    The EPR spectrum of the Y@C(82) molecules isolated in solid argon matrix was recorded for the first time at a temperature of 5 K. The isotropic hyperfine coupling constant (hfcc) A(iso) = 0.12 +/- 0.02 mT on the nucleus (89)Y as derived from the EPR spectrum is found in more than two times greater than that obtained in previous EPR measurements in liquid solutions. Comparison of the measured hfcc on a metal atom with that predicted by density-functional theory calculations (PBE/L22) indicate that relativistic method provides good agreement between experiment in solid argon and theory. Analysis of the DFT calculated dipole-dipole hf-interaction tensor and electron spin distribution in the endometallofullerenes with encaged group 3 metal atoms Sc, Y and La has been performed. It shows that spin density on the scandium atom represents the Sc d(yz) orbital lying in the symmetry plane of the C(2v) fullerene isomer and interacting with two carbon atoms located in the para-position on the fullerene hexagon. In contrast, the configuration of electron spin density on the heavier atoms, Y and La, is associated with the hybridized orbital formed by interaction of the metal d(yz) and p(y) electronic orbitals.

  6. Miniaturized matrix solid-phase dispersion combined with ultrasound-assisted dispersive liquid-liquid microextraction for the determination of three pyrethroids in soil.

    Wang, Hui; Yan, Hongyuan; Qiao, Jindong


    A simple and miniaturized pretreatment procedure combining matrix solid-phase dispersion (MSPD) with ultrasound-assisted dispersive liquid-liquid microextraction (UA-DLLME) technique was proposed in first time for simultaneous determination of three pyrethroids (fenpropathrin, cyhalothrin and fenvalerate) in soils. The solid samples were directly extracted using MSPD procedure, and the eluent of MSPD was used as the dispersive solvent of the followed DLLME procedure for further purification and enrichment of the analytes before GC-ECD analysis. Good linear relationships were obtained for all the analytes in a range of 5.0-500.0 ng/g with LOQs (S/N=10) ranged from 1.51 to 3.77 ng/g. Average recoveries at three spiked levels were in a range of 83.6-98.5% with RSD≤7.3%. The present method combined the advantages of MSPD and DLLME, and was successfully applied for the determination of three pyrethroids in soil samples.

  7. [Determination of gibberellins in Arabidopsis thaliana by matrix solid-phase dispersion extraction and high performance liquid chromatography-tandem mass spectrometry].

    Wang, Lu; Wu, Qian; Duan, Chunfeng; Wu, Dapeng; Guan, Yafeng


    A method for the analysis of gibberellin A1 (GA1), gibberellin A3 (GA3) and gibberellin A4 (GA4) in Arabidopsis thaliana by matrix solid-phase dispersion extraction (MSPD) and high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS) was developed. The solid sample of Arabidopsis thaliana was gently blended with C18 to obtain a homogeneous mixture. This mixture was transferred to an SPE cartridge filled with 0.5 g C18 to form a MSPD column. GA1, GA3 and GA4 were eluted with cold 80% methanol aqueous solution. The target compounds were separated on a C18 column with a gradient elution of 0.05% formic acid aqueous solution and acetonitrile as the mobile phase. The identification and quantification were carried out by using electrospray ionization in negative ion mode (ESI-) with multiple reaction monitoring (MRM). The linear ranges for GA1, GA3 and GA4 were all from 10 to 300 ng/g with correlation coefficients greater than 0.98. The limits of detection were in the range of 1.1-4.1 ng/g. The average recoveries and relative standard deviations were 54.7%-102.6% and 3.2%-12.8% respectively in the spiked range of 10-50 ng/g. The method is simple, sensitive, efficient and accurate. It is suitable for the confirmation and quantitative determination of GA1, GA3 and GA4 in Arabidopsis thaliana.

  8. Optimization of matrix solid-phase dispersion for the rapid determination of salicylate and benzophenone-type UV absorbing substances in marketed fish.

    Tsai, Dung-Ying; Chen, Chien-Liang; Ding, Wang-Hsien


    A simple and effective method for the rapid determination of five salicylate and benzophenone-type UV absorbing substances in marketed fish is described. The method involves the use of matrix solid-phase dispersion (MSPD) prior to their determination by on-line silylation gas chromatography tandem mass spectrometry (GC-MS/MS). The parameters that affect the extraction efficiency were optimized using a Box-Behnken design method. The optimal extraction conditions involved dispersing 0.5g of freeze-dried powdered fish with 1.0g of Florisil using a mortar and pestle. This blend was then transferred to a solid-phase extraction (SPE) cartridge containing 1.0g of octadecyl bonded silica (C18), as the clean-up co-sorbent. The target analytes were then eluted with 7mL of acetonitrile. The extract was derivatized on-line in the GC injection-port by reaction with a trimethylsilylating (TMS) reagent. The TMS-derivatives were then identified and quantitated by GC-MS/MS. The limits of quantitation (LOQs) were less than 0.1ng/g. Copyright © 2014 Elsevier Ltd. All rights reserved.

  9. Solid matrix priming with chitosan enhances seed germination and seedling invigoration in mung bean under salinity stress

    Sujoy SEN


    Full Text Available The objective of present study was to evaluate the response of the mung bean seeds of ‘Sonali B1’ variety primed with chitosan in four different concentrations (0, 0.1%, 0.2% and 0.5% under salinity stress of five different concentrations (i.e., 0, 4, 6, 8 and 12 dS*mm-1 and halotolerance pattern by applying Celite as matrix at three different moisture levels (5%, 10% and 20%. Improved germination percentage, germination index, mean germination time, coefficient of velocity of germination along with root and shoot length was observed comparing with control. Germination stress tolerance index (GSI, plant height stress tolerance index (PHSI and root length stress tolerance index (RLSI were used to evaluate the tolerance of the mung bean seeds against salinity stress induced by chitosan. Results of GSI, PHSI, RLSI showing noteworthy inhibitory effect of salinity stress in control set was significantly less pronounced in chitosan treated seedlings. Chitosan can remarkably alleviate the detrimental effect of salinity up to the level of 6 dS*m-1, beyond which no improvement was noticed. In conclusion present investigation revealed that chitosan is an ideal elicitor for enhancing the speed of germination and seedling invigoration that synchronize with emergence of radicle and salinity stress tolerance.

  10. Calibration of the complex matrix effects on the sampling of polycyclic aromatic hydrocarbons in milk samples using solid phase microextraction.

    Lin, Wei; Wei, Songbo; Jiang, Ruifen; Zhu, Fang; Ouyang, Gangfeng


    Solid phase microextraction (SPME), a simple, fast and promising sampling technique, has been widely used for complex sample analysis. However, complex matrices could modify the absorption property of coatings as well as the uptake kinetics of analytes, eventually biasing the quantification results. In the current study, we demonstrated the feasibility of a developed calibration method for the analysis of polycyclic aromatic hydrocarbons (PAHs) in complex milk samples. Effects of the complex matrices on the SPME sampling process and the sampling conditions were investigated. Results showed that short exposure time (pre-equilibrium SPME, PE-SPME) could increase the lifetime of coatings, and the complex matrices in milk samples could significantly influence the sampling kinetics of SPME. In addition, the optimized sampling time, temperature and dilution factor for PAHs were 10 min, 85 °C and 20, respectively. The obtained LODs and LOQs of all the PAHs were 0.1-0.8 ng/mL and 1.4-4.7 ng/mL, respectively. Furthermore, the accuracy of the proposed PE-SPME method for milk sampling was validated by the recoveries of the studied compounds in two concentration levels, which ranged from 75% to 110% for all the compounds. Finally, the proposed method was applied to the screening of PAHs in milk samples.

  11. Determination of nucleoside analog mono-, di-, and tri-phosphates in cellular matrix by solid phase extraction and ultra-sensitive LC-MS/MS detection.

    Bushman, Lane R; Kiser, Jennifer J; Rower, Joseph E; Klein, Brandon; Zheng, Jia-Hua; Ray, Michelle L; Anderson, Peter L


    An ultra-sensitive liquid chromatography tandem mass spectrometry (LC-MS/MS) assay was developed and validated to facilitate the assessment of clinical pharmacokinetics of nucleotide analogs from lysed intracellular matrix. The method utilized a strong anion exchange isolation of mono-(MP), di-(DP), and tri-phosphates (TP) from intracellular matrix. Each fraction was then dephosphorylated to the parent moiety yielding a molar equivalent to the original nucleotide analog intracellular concentration. The analytical portion of the methodology was optimized in specific nucleoside analog centric modes (i.e. tenofovir (TFV) centric, zidovudine (ZDV) centric), which included desalting/concentration by solid phase extraction and detection by LC-MS/MS. Nucleotide analog MP-, DP-, and TP-determined on the TFV centric mode of analysis include TFV, lamivudine (3TC), and emtricitibine (FTC). The quantifiable linear range for TFV was 2.5-2000 fmol/sample, and that for 3TC/FTC was 0.1 200 pmol/sample. Nucleoside analog MP-, DP-, and TP-determined on the ZDV centric mode of analysis included 3TC and ZDV. The quantifiable linear range for 3TC was 0.1 100 pmol/sample, and 5-2000 fmol/sample for ZDV. Stable labeled isotopic internal standards facilitated accuracy and precision in alternative cell matrices, which supported the intended use of the method for MP, DP, and TP determinations in various cell types. The method was successfully applied to clinical research samples generating novel intracellular information for TFV, FTC, ZDV, and 3TC nucleotides. This document outlines method development, validation, and application to clinical research.

  12. Simplified matrix solid phase dispersion procedure for the determination of parabens and benzophenone-ultraviolet filters in human placental tissue samples.

    Vela-Soria, F; Rodríguez, I; Ballesteros, O; Zafra-Gómez, A; Ballesteros, L; Cela, R; Navalón, A


    In recent decades, the industrial development has resulted in the appearance of a large amount of new chemicals that are able to produce disorders in the human endocrine system. These substances, so-called endocrine disrupting chemicals (EDCs), include many families of compounds, such as parabens and benzophenone-UV filters. Taking into account the demonstrated biological activity of these compounds, it is necessary to develop new analytical procedures to assess the exposure in order to establish, in an accurate way, relationships between EDCs and harmful health effects in population. In the present work, a new method based on a simplified sample treatment by matrix solid phase dispersion (MSPD) followed by ultrahigh performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) analysis, is validated for the determination of four parabens (methyl-, ethyl-, propyl- and butylparaben) and six benzophenone-UV filters (benzophenone-1, benzophenone-2, benzophenone-3, benzophenone-6, benzophenone-8 and 4-hydroxybenzophenone) in human placental tissue samples. The extraction parameters were accurately optimized using multivariate optimization strategies. Ethylparaben ring-13C6 and benzophenone-d10 were used as surrogates. The found limits of quantification ranged from 0.2 to 0.4 ng g(-1) and inter-day variability (evaluated as relative standard deviation) ranged from 5.4% to 12.8%. The method was validated using matrix-matched standard calibration followed by a recovery assay with spiked samples. Recovery rates ranged from 96% to 104%. The method was satisfactorily applied for the determination of compounds in human placental tissue samples collected at the moment of delivery from 10 randomly selected women. Copyright © 2014 Elsevier B.V. All rights reserved.

  13. Simultaneous analysis of 45 pharmaceuticals and personal care products in sludge by matrix solid-phase dispersion and liquid chromatography tandem mass spectrometry.

    Li, Mingyue; Sun, Qian; Li, Yan; Lv, Min; Lin, Lifeng; Wu, Yang; Ashfaq, Muhammad; Yu, Chang-Ping


    Pharmaceuticals and personal care products (PPCPs) are a class of emerging contaminants widely distributed in the wastewater treatment system. The simultaneous analysis of multiple PPCPs in the sludge, which is a complex matrix, is still not fully studied. In this study, a procedure based on matrix solid-phase dispersion (MSPD) for the extraction of PPCPs from the sludge with determination by liquid chromatography tandem mass spectrometry (LC-MS/MS) was investigated. Forty-five PPCPs, including antibiotics, nonsteroidal anti-inflammatory drugs, β-blockers, antidepressants, antimicrobial agents, preservatives, UV filters, and so on, were studied. MSPD parameters, including the sorbent materials, the ratio of sample to sorbent, the eluent composition, and the elution volumes, were sequentially optimized. Best results were achieved by 0.1 g of sludge homogenized with 0.4 g of C18-bonded silica sorbent and elution by 6 mL methanol and 10 mL acetonitrile/5 % oxalic acid (8/2, v/v). The method quantification limits for the 45 PPCPs ranged 0.117-5.55 μg/kg. The PPCP recoveries ranged from 50.3 to 107 % with relative standard deviation lower than 15 %. The proposed method was applied to analyze PPCPs in the sludge collected from a domestic wastewater treatment plant over 1 year. Thirteen PPCPs were detected, with the concentrations of ofloxacin and triclocarban more than 1000 μg/kg. Temporal variations of the PPCP levels were observed. Thus, MSPD-LC-MS/MS method could achieve good sensitivity and recovery for the target PPCP analysis in the sludge samples, while MSPD provided one-step sample preparation which was easier and faster to perform compared to the commonly used methods. Graphical abstract Workflow of MSPD and LC-MS/MS chromatograms for PPCP analysis.

  14. Matrix solid-phase dispersion combined to liquid chromatography-tandem mass spectrometry for the determination of paraben preservatives in mollusks.

    Villaverde-de-Sáa, Eugenia; Rodil, Rosario; Quintana, José Benito; Cela, Rafael


    A method for the extraction and determination of seven parabens, esters of 4-hydroxybenzoic acid, widely used as preservatives in personal care products, pharmaceuticals, etc., and two chlorinated derivatives (mono- and di-chloro methyl paraben) from mollusk samples was developed by combining matrix solid-phase dispersion (MSPD) and liquid chromatography-tandem mass spectrometry. MSPD parameters, such as solvent, solid support and clean-up sorbent, were optimized. Besides, since blank problems were observed for some parabens, these were investigated and blanks were tackled by precleaning all sorbents prior to use. Under final conditions, 0.5g of freeze-dried mollusk were dispersed with 1.2g of silica and packed into a cartridge containing 3g of C18, as on-line clean-up sorbent. This cartridge was eluted with 10mL of acetonitrile, evaporated and reconstituted in methanol for analysis. In the validation stage, successful linearity (R(2)>0.999), recoveries (between 71 and 117% for most analytes), precision (RSD lower than 21%) and limits of detection and quantification (LOD and LOQ, lower than 0.4 and 1.4ngg(-1) dry weight respectively) levels were achieved. Finally, the new methodology was applied to mussel, clam and cockle samples. Methyl paraben was above the LOQ in five of the six samples (not found in one clam sample) at concentrations up to 7ngg(-1) dry weight. Ethyl paraben was found above the LOQ in mussel and cockle samples at a concentration level around 0.3ngg(-1). n-Propyl paraben was only above the LOQ in one mussel sample.

  15. Universal chemiluminescence flow-through device based on directed self-assembly of solid-state organic chromophores on layered double hydroxide matrix.

    Wang, Zhihua; Teng, Xu; Lu, Chao


    In this work, a universal chemiluminescence (CL) flow-through device suitable for various CL resonance energy transfer (CRET) systems has been successfully fabricated. Highly efficient CRET in solid-state photoactive organic molecules can be achieved by assembling them on the surface of layered double hydroxides (LDHs). We attribute these observations to the suppression of the intermolecular π-π stacking interactions among aromatic rings and the improvement of molecular orientation and planarity in the LDH matrix, enabling a remarkable increase in fluorescence lifetime and quantum yield of organic molecules. Under optimal conditions, using peroxynitrous acid-fluorescein dianion (FLUD) as a model CRET system, trace FLUD (10 μM) was assembled on the surface of LDHs. Peroxynitrous acid/nitrite could be assayed in the range of 1.0-500 μM, and the detection limit for peroxynitrous acid/nitrite (S/N = 3) was 0.6 μM. This CL flow-through device exhibited operational stability, high reproducibility, and long lifetime. While LDHs were immobilized in a flow-through device in the absence of FLUD, the detection limit for peroxynitrous acid/nitrite was 100 μM. On the other hand, FLUD at the same concentration can not enhance the CL intensity of peroxynitrous acid system. This fabricated CL flow-through column has been successfully applied to determine nitrite in sausage samples with recoveries of 98-102%. These satisfactory results demonstrated that our studies pave a novel way toward flow-through column-based CRET using solid-state organic molecules as acceptors for signal amplification.

  16. Microscopic Dynamics and Topology of Polymer Rings Immersed in a Host Matrix of Longer Linear Polymers: Results from a Detailed Molecular Dynamics Simulation Study and Comparison with Experimental Data

    George D. Papadopoulos


    Full Text Available We have performed molecular dynamics (MD simulations of melt systems consisting of a small number of long ring poly(ethylene oxide (PEO probes immersed in a host matrix of linear PEO chains and have studied their microscopic dynamics and topology as a function of the molecular length of the host linear chains. Consistent with a recent neutron spin echo spectroscopy study (Goossen et al., Phys. Rev. Lett. 2015, 115, 148302, we have observed that the segmental dynamics of the probe ring molecules is controlled by the length of the host linear chains. In matrices of short, unentangled linear chains, the ring probes exhibit a Rouse-like dynamics, and the spectra of their dynamic structure factor resemble those in their own melt. In striking contrast, in matrices of long, entangled linear chains, their dynamics is drastically altered. The corresponding dynamic structure factor spectra exhibit a steep initial decay up to times on the order of the entanglement time τe of linear PEO at the same temperature but then they become practically time-independent approaching plateau values. The plateau values are different for different wavevectors; they also depend on the length of the host linear chains. Our results are supported by a geometric analysis of topological interactions, which reveals significant threading of all ring molecules by the linear chains. In most cases, each ring is simultaneously threaded by several linear chains. As a result, its dynamics at times longer than a few τe should be completely dictated by the release of the topological restrictions imposed by these threadings (interpenetrations. Our topological analysis did not indicate any effect of the few ring probes on the statistical properties of the network of primitive paths of the host linear chains.

  17. Determination of paraben preservatives in seafood using matrix solid-phase dispersion and on-line acetylation gas chromatography-mass spectrometry.

    Djatmika, Rosalina; Hsieh, Chih-Chung; Chen, Jhih-Ming; Ding, Wang-Hsien


    An effective method for determining four commonly detected paraben preservatives (methyl, ethyl, propyl and butyl paraben) in marketed seafood is presented. This method employs matrix solid-phase dispersion (MSPD) before identification and quantification of the paraben preservatives via on-line acetylation gas chromatography-mass spectrometry (GC-MS). Parameters affecting the extraction efficiency of MSPD were optimized through a Box-Behnken design method. Under optimal condition, 0.5-g of freeze-dried seafood was mixed with 0.5-g of anhydrous sodium sulfate, and dispersed with 1.0-g of Florisil using vortex. After that, the blend was transferred to a glass column containing 1.5-g of silica gel+C18 (w/w, 9:1), which acted as clean-up co-sorbents. Then, target analytes were eluted with 12mL of acetonitrile. The extract was then derivatized on-line in the GC injection-port through reaction with acetic anhydride, and the identity and quantity of the target analytes were determined by the GC-MS system. The limits of quantitation (LOQs) were 0.2 to 1.0ng/g (dry weight). Preliminary results showed that the total concentrations of four selected parabens ranged from 16.7 to 44.7ng/g (dry weight).

  18. Optimization of a method based on micro-matrix solid-phase dispersion (micro-MSPD for the determination of PCBs in mussel samples

    Nieves Carro


    Full Text Available This paper reports the development and optimization of micro-matrix solid-phase dispersion (micro-MSPD of nine polychlorinated biphenyls (PCBs in mussel samples (Mytilus galloprovincialis by using a two-level factorial design. Four variables (amount of sample, anhydrous sodium sulphate, Florisil and solvent volume were considered as factors in the optimization process. The results suggested that only the interaction between the amount of anhydrous sodium sulphate and the solvent volume was statistically significant for the overall recovery of a trichlorinated compound, CB 28. Generally most of the considered species exhibited a similar behaviour, the sample and Florisil amounts had a positive effect on PCBs extractions and solvent volume and sulphate amount had a negative effect. The analytical determination and confirmation of PCBs were carried out by using GC-ECD and GC-MS/MS, respectively. The method was validated having satisfactory precision and accuracy with RSD values below 6% and recoveries between 81 and 116% for all congeners. The optimized method was applied to the extraction of real mussel samples from two Galician Rías.

  19. Molecularly Imprinted Nanomicrospheres as Matrix Solid-Phase Dispersant Combined with Gas Chromatography for Determination of Four Phosphorothioate Pesticides in Carrot and Yacon

    Mengchun Zhou


    Full Text Available An efficient, rapid, and selective method for sample pretreatment, namely, molecularly imprinted matrix solid-phase dispersion (MI-MSPD coupled with gas chromatography (GC, was developed for the rapid isolation of four phosphorothioate organophosphorus pesticides (tolclofos-methyl, phoxim, chlorpyrifos, and parathion-methyl from carrot and yacon samples. New molecularly imprinted polymer nanomicrospheres were synthesized by using typical structural analogue tolclofos-methyl as a dummy template via surface grafting polymerization on nanosilica. Then, these four pesticides in carrot and yacon were extracted and adsorbed using the imprinted nanomicrospheres and further determined by gas chromatography. Under the optimized conditions, a good linearity of four pesticides was obtained in a range of 0.05–17.0 ng·g−1 with R varying from 0.9971 to 0.9996, and the detection limit of the method was 0.012~0.026 ng·g−1 in carrot and yacon samples. The recovery rates at two spiked levels were in the range of 85.4–105.6% with RSD ≤9.6%. The presented MI-MSPD method combined the advantages of MSPD for allowing the extraction, dispersion, and homogenization in two steps and the advantages of MIPs for high affinity and selectivity towards four phosphorothioate pesticides, which could be applied to the determination of pesticide residues in complicated vegetal samples.

  20. Simultaneous determination of fumonisins B1 and B2 in different types of maize by matrix solid phase dispersion and HPLC-MS/MS.

    de Oliveira, Gabriel Barros; de Castro Gomes Vieira, Carolyne Menezes; Orlando, Ricardo Mathias; Faria, Adriana Ferreira


    This work involved the optimization and validation of a method, according to Directive 2002/657/EC and the Analytical Quality Assurance Manual of Ministério da Agricultura, Pecuária e Abastecimento, Brazil, for simultaneous extraction and determination of fumonisins B1 and B2 in maize. The extraction procedure was based on a matrix solid phase dispersion approach, the optimization of which employed a sequence of different factorial designs. A liquid chromatography-tandem mass spectrometry method was developed for determining these analytes using the selected reaction monitoring mode. The optimized method employed only 1g of silica gel for dispersion and elution with 70% ammonium formate aqueous buffer (50mmolL(-1), pH 9), representing a simple, cheap and chemically friendly sample preparation method. Trueness (recoveries: 86-106%), precision (RSD ≤19%), decision limits, detection capabilities and measurement uncertainties were calculated for the validated method. The method scope was expanded to popcorn kernels, white maize kernels and yellow maize grits. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. In-Vial Micro-Matrix-Solid Phase Dispersion for the Analysis of Fragrance Allergens, Preservatives, Plasticizers, and Musks in Cosmetics

    Maria Celeiro


    Full Text Available Fragrance allergens, preservatives, plasticizers, and synthetic musks are usually present in cosmetic and personal care products formulations and many of them are subjected to use restrictions or labeling requirements. Matrix solid-phase dispersion (MSPD is a very suitable analytical technique for the extraction of these compounds providing a simple, low cost sample preparation, and the possibility of performing both extraction and clean-up in one step, reducing possible contamination and analyte losses. This extraction technique has been successfully applied to many cosmetics ingredients allowing obtaining quantitative recoveries. A new very simple micro-MSPD procedure performing the disruption step in a vial is proposed for the gas chromatography-mass spectrometry (GC-MS analysis of 66 chemicals usually present in cosmetics and personal care products. The method was validated showing general recoveries between 80% and 110%, relative standard deviation (RSD values lower than 15%, and limits of detection (LODs below 30 ng·g−1. The validated method was applied to a broad range of cosmetics and personal care products, including several products intended for baby care.

  2. Single "click" synthesis of a mixed-mode silica sorbent and application in matrix solid-phase dispersion extraction of β-agonists from porcine liver.

    Zhu, Yuling; Yang, Siwen; Chen, Gang; Xing, Jun


    A single "click" strategy is proposed for the preparation of a reversed-phase/weak cation-exchange mixed-mode silica-based sorbent (silica-WCX). Upon this strategy, both 1-dodecyne and 5-hexynoic acid were simultaneously immobilized onto azide-silica in varied ratio via Cu (I)-catalyzed azide-alkyne cycloaddition click reaction. The chemical compositions of silica-WCXs were characterized by elemental analysis, acid-base titration and Fourier transform-infrared spectroscopy. The results indicated that the actual mole ratio of n-dodecyl to carboxylic group on the sorbent is almost the same as the reactant ratio of 1-dodecyne to 5-hexynoic acid, and the repeatability of synthesis method is good. After that, two β-agonists, clenbuterol and ractopamine, were selected as model drug residues to evaluate the applicability of silica-WCX in matrix solid-phase dispersion extraction for the determination of basic drug residues in porcine liver by HPLC/UV. In comparison with some commercial sorbents, silica-WCX exhibited higher recoveries and better purification capability. Under the optimized conditions, linearity ranges were between 0.04 and 8.0μg/g for both analytes with coefficients of determination (R(2)) higher than 0.9997. The average recoveries at three spiked levels ranged from 92.5% to 105.0% with RSDs less than 6.6%.

  3. Application of matrix solid-phase dispersion to the propham and maleic hydrazide determination in potatoes by differential pulse voltammetry and HPLC.

    Arribas, Alberto Sánchez; Bermejo, Esperanza; Chicharro, Manuel; Zapardiel, Antonio


    The application of the matrix solid-phase dispersion (MSPD) process as sample treatment in connection with the electrochemical detection is studied for the first time. For this purpose, a novel methodology is introduced for the extraction of propham and maleic hydrazide herbicides from potatoes samples based in the MSPD process prior to their electrochemical detection. Potato samples disruption was done by blending them with C(8) bonded-phase and selective herbicide extraction was achieved by successive treatment of the blended with 50mM phosphate buffer pH 7.4 (for maleic hydrazide) and methanol (for propham). The extraction procedure efficiency was estimated using differential pulse voltammetry in potato samples spiked with the herbicides yielding recovery values of 98% and 68% for propham and maleic hydrazide, respectively. No significant adverse effect of the MSPD process was observed on the herbicides electrochemical signals. For comparison, recovery studies using HPLC with UV detection were carried out and a good correlation in the results obtained by using both techniques was observed.

  4. Acellular dermal matrix and negative pressure wound therapy: a tissue-engineered alternative to free tissue transfer in the compromised host.

    Menn, Zachary K; Lee, Edward; Klebuc, Michael J


    Free tissue transfer has revolutionized lower extremity reconstruction; however, its use in elderly patients with multiple medical problems can be associated with elevated rate s of perioperative morbidity and mortality. This study evaluates the use of acellular dermal matrix (ADM) in conjunction with negative pressure wound therapy (NPWT) and delayed skin graft application as an alternative to free tissue transfer in this compromised population. Bilayer, ADM (Integra, Plainsboro, NJ) was used in conjunction with NPWT (Wound V.A.C, Kinetic Concepts Inc., San Antonio, TX) to achieve vascularized coverage of complex lower extremity wounds with denuded tendon and bone in elderly, medically compromised patients. Following incorporation, the matrix was covered with split-thickness skin graft. Four patients (age range, 50 to 76 years) with multiple medical comorbidities were treated with the above protocol. The average time to complete vascularization of the matrix was 29 days. Definitive closure with split-thickness skin graft was achieved in three patients and one wound healed by secondary intention. No medical or surgical complications were encountered and stable soft tissue coverage was achieved in all patients. This early experience suggests that dermal substitute and NPWT with delayed skin graft application can provide a reasonable tissue-engineered alternative to free tissue transfer in the medically compromised individual.

  5. Synthesis of diluted magnetic semiconductor Bi{sub 2−x}Mn{sub x}Te{sub 3} nanocrystals in a host glass matrix

    Silva, R.S. [Instituto de Ciências Exatas, Naturais e Educação (ICENE), Departamento de Física, Universidade Federal do Triângulo Mineiro, 38025-180 Uberaba, Minas Gerais (Brazil); Mikhail, H.D., E-mail: [Instituto de Ciências Tecnológicas e Exatas (ICTE), Departamento de Engenharia Mecânica, Universidade Federal do Triângulo Mineiro, 38064-200 Uberaba, Minas Gerais (Brazil); Pavani, R. [Instituto de Ciências Exatas, Naturais e Educação (ICENE), Departamento de Física, Universidade Federal do Triângulo Mineiro, 38025-180 Uberaba, Minas Gerais (Brazil); Cano, N.F. [Departamento de Ciências do Mar, Universidade Federal de São Paulo, 11030-400 Santos, São Paulo (Brazil); Silva, A.C.A.; Dantas, N.O. [Instituto de Física, Laboratório de Novos Materiais Isolantes e Semicondutores (LNMIS), Universidade Federal de Uberlândia, 38400-902 Uberlândia, Minas Gerais (Brazil)


    Diluted magnetic semiconductors of manganese doped in bismuth-telluride nanocrystals (Bi{sub 2−x}Mn{sub x}Te{sub 3} NCs) were grown in a glass matrix and investigated by Transmission Electron Microscopy, X-Ray Diffraction, Atomic Force Microscopy/Magnetic Force Microscopy, and Electron Paramagnetic Resonance. TEM images showed that the nanocrystals formed within the glass matrix were nearly spherical, with average sizes between 4 and 5 nm, and d{sub 015}-spacing of approximately 0.322 nm, which corresponds to the (015) interplanar distance in Bi{sub 2}Te{sub 3} bulk. The diffraction patterns showed that the diffraction peak associated with the (015) plane of the Bi{sub 2−x}Mn{sub x}Te{sub 3} nanocrystals shifts to larger diffraction angles as manganese (Mn) concentration increases, suggesting that the Mn{sup 2+} ions are substitutional defects occupying Bi sites (Mn{sub Bi}). AFM and MFM measurements showed magnetic phase contrast patterns, providing further evidence of Mn{sup 2+} ion incorporation in the nanocrystal structure. EPR signal of manganese ion incorporation and valence states in the crystalline structure of the Bi{sub 2}Te{sub 3} nanocrystals confirmed the presence of the Mn{sup 2+} state. - Highlights: • Bi{sub 2−x}Mn{sub x}Te{sub 3} NCs were synthesized in a glass matrix by fusion method. • Transmission Electronic Microscopy shows the formation of Bi{sub 2−x}Mn{sub x}Te{sub 3} NCs. • The sp-d exchange interaction in DMS NCs can be evidenced by X Ray-Diffraction and Magnetic Force Microscopy. • Electron Paramagnetic Resonance spectra confirmed that Mn{sup 2+} ions are located in two distinct Bi{sub 2}Te{sub 3} NCs sites.

  6. Rapid Detection and Identification of Candidemia by Direct Blood Culturing on Solid Medium by Use of Lysis-Centrifugation Method Combined with Matrix-Assisted Laser Desorption Ionization-Time of Flight Mass Spectrometry (MALDI-TOF MS).

    Idelevich, Evgeny A; Grünastel, Barbara; Becker, Karsten


    Candida sepsis is a life-threatening condition with increasing prevalence. In this study, direct blood culturing on solid medium using a lysis-centrifugation procedure enabled successful Candida species identification by matrix-assisted laser desorption-ionization time of flight mass spectrometry on average 3.8 h (Sabouraud agar) or 7.4 h (chocolate agar) before the positivity signal for control samples in Bactec mycosis-IC/F or Bactec Plus aerobic/F bottles, respectively. Direct culturing on solid medium accelerated candidemia diagnostics compared to that with automated broth-based systems. Copyright © 2016 American Society for Microbiology.

  7. Analysis of multi-class preservatives in leave-on and rinse-off cosmetics by matrix solid-phase dispersion.

    Sanchez-Prado, Lucia; Alvarez-Rivera, Gerardo; Lamas, J Pablo; Lores, Marta; Garcia-Jares, Carmen; Llompart, Maria


    Matrix solid-phase extraction has been successfully applied for the determination of multi-class preservatives in a wide variety of cosmetic samples including rinse-off and leave-on products. After extraction, derivatization with acetic anhydride, and gas chromatography-mass spectrometry analysis were performed. Optimization studies were done on real non-spiked and spiked leave-on and rinse-off cosmetic samples. The selection of the most suitable extraction conditions was made using statistical tools such as ANOVA, as well as factorial experimental designs. The final optimized conditions were common for both groups of cosmetics and included the dispersion of the sample with Florisil (1:4), and the elution of the MSPD column with 5 mL of hexane/acetone (1:1). After derivatization, the extract was analyzed without any further clean-up or concentration step. Accuracy, precision, linearity and detection limits were evaluated to assess the performance of the proposed method. The recovery studies on leave-on and rinse-off cosmetics gave satisfactory values (>78% for all analytes in all the samples) with an average relative standard deviation value of 4.2%. The quantification limits were well below those set by the international cosmetic regulations, making this multi-component analytical method suitable for routine control. The analysis of a broad range of cosmetics including body milk, moisturizing creams, anti-stretch marks creams, hand creams, deodorant, shampoos, liquid soaps, makeup, sun milk, hand soaps, among others, demonstrated the high use of most of the target preservatives, especially butylated hydroxytoluene, methylparaben, propylparaben, and butylparaben.

  8. Determination of isothiazolinone preservatives in cosmetics and household products by matrix solid-phase dispersion followed by high-performance liquid chromatography-tandem mass spectrometry.

    Alvarez-Rivera, Gerardo; Dagnac, Thierry; Lores, Marta; Garcia-Jares, Carmen; Sanchez-Prado, Lucia; Lamas, J Pablo; Llompart, Maria


    In this work, the development of a new efficient methodology applying, for the first time, matrix solid phase dispersion (MSPD) for the determination of sensitizer isothiazolinone biocides in cosmetics and household products - 2-methyl-3-isothiazolinone (MI), 5-chloro-2-methyl-3-isothiazolinone (CMI), 1,2-benzisothiazolinone (BzI) and 2-octyl-3-isothiazolinone (OI) - is described. The main factors affecting the MSPD extraction procedure, the dispersive phase and the elution solvent, are assessed and optimized through a multicategorical experimental design, using a real cosmetic sample. The most suitable extraction conditions comprise the use of 2g of florisil as dispersive phase and 5 mL of methanol as elution solvent. Subsequently, the extract is readily analyzed by HPLC-MS/MS without any further clean-up or concentration steps. Method performance was evaluated demonstrating to have a broad linear range (R(2)>0.9980) and limits of detection (LOD) and quantification (LOQ) at the low nanogram per gram level, which are well below the required limits for UE regulation compliance. Satisfactory recoveries above 80%, except for MI (mean values close to 60%), were obtained. In all cases, the method precision (% RSD) was lower than 7%, making this low cost extraction method reliable for routine control. The validated methodology was finally applied to the analysis of a wide variety of cosmetics and household products. Most of the real samples analyzed have been shown to comply with the current European Cosmetic Regulation, although the results obtained for some rinse-off cosmetics (e.g. baby care products) revealed high isothiazolinone content.

  9. Multivariate optimisation of an ultrasound assisted-matrix solid-phase dispersion method combined with LC-fluorescence detection for simultaneous extraction and determination of aflatoxins in pistachio nut samples.

    Manoochehri, Mahboobeh; Asgharinezhad, Ali Akbar; Safaei, Mahdi


    This paper describes the application of ultrasound-assisted matrix solid-phase dispersion as an extraction and clean-up procedure for aflatoxins (B1, B2, G1 and G2) and subsequent determination by LC-fluorescence detection. A Box-Behnken design was used to determine the parameters influencing the extraction procedure through response surface methodology and experimental design. The influence of different variables including type of dispersing phase, sample-to-dispersing phase ratio, type and quantity of clean-up phase, ultrasonication time, ultrasonication temperature, nature and volume of the elution solvent were investigated in the optimisation study. C18, graphitic carbon black and acetonitrile were selected as dispersing phase, clean-up phase and elution solvent, respectively. The optimised values were sample-to-dispersing phase ratio of 1:1, 50 mg of graphitic carbon black, 11 min ultrasonication time, 30°C ultrasonication temperature and 3 ml acetonitrile. Under the optimal conditions the limits of detection (LODs) were ranged from 0.04-0.11 µg kg(-1) and the relative standard deviations (RSDs) of the extraction method were less than 8.6%. The recoveries of the matrix solid-phase dispersion process ranged from 74% to 78% with relative standard deviation lower than 9% in all cases. Finally, the matrix solid-phase dispersion was successfully applied to extraction of trace amounts of aflatoxins in pistachio samples.

  10. Role of the Emp Pilus Subunits of Enterococcus faecium in Biofilm Formation, Adherence to Host Extracellular Matrix Components, and Experimental Infection.

    Montealegre, Maria Camila; Singh, Kavindra V; Somarajan, Sudha R; Yadav, Puja; Chang, Chungyu; Spencer, Robert; Sillanpää, Jouko; Ton-That, Hung; Murray, Barbara E


    Enterococcus faecium is an important cause of hospital-associated infections, including urinary tract infections (UTIs), bacteremia, and infective endocarditis. Pili have been shown to play a role in the pathogenesis of Gram-positive bacteria, including E. faecium We previously demonstrated that a nonpiliated ΔempABC::cat derivative of E. faecium TX82 was attenuated in biofilm formation and in a UTI model. Here, we studied the contributions of the individual pilus subunits EmpA, EmpB, and EmpC to pilus architecture, biofilm formation, adherence to extracellular matrix (ECM) proteins, and infection. We identified EmpA as the tip of the pili and found that deletion of empA reduced biofilm formation to the same level as deletion of the empABC operon, a phenotype that was restored by reconstituting in situ the empA gene. Deletion of empB also caused a reduction in biofilm, while EmpC was found to be dispensable. Significant reductions in adherence to fibrinogen and collagen type I were observed with deletion of empA and empB, while deletion of empC had no adherence defect. Furthermore, we showed that each deletion mutant was significantly attenuated in comparison to the isogenic parental strain, TX82, in a mixed-inoculum UTI model (P Emp pilins are important for E. faecium to cause infection in the urinary tract.

  11. The biomechanical behavior and host response to porcine-derived small intestine submucosa, pericardium and dermal matrix acellular grafts in a rat abdominal defect model.

    Zhang, Jian; Wang, Guan Yu; Xiao, Yi Pin; Fan, Lie Ying; Wang, Qiang


    Several porcine-derived acellular biologic grafts are increasingly used in abdominal wall reconstruction due to the limitations of synthetic meshes in many clinical situations. However, relatively little is known so far about their comparative mechanical characteristics and performance after defect repair. We therefore investigated three most commonly used porcine-derived acellular biomaterials, small intestine submucosa (P-SIS), pericardium (P-PC) and acellular dermal matrix (P-ADM) immediately after prepared, and their effectiveness, biomechanical and histological characteristics in repairing full-thickness abdominal defect in a rat model. P-PC had the best native performance in the burst strength, tensile strength and ball burst among the three porcine-derived scaffolds. P-SIS showed a significantly higher water vapor transmission in comparison with P-PC or P-ADM. Abdominal wall defects in rats were all satisfied repaired with P-SIS, P-PC or P-ADM. No laxity or fistula was observed in the repaired abdominal wall in the P-SIS group up to 8 weeks after surgery. However, there was a tendency for high postoperative abdominal eventration in the P-ADM and P-PC groups as compared with the P-SIS group. With regard to overall aspects of the postoperative laxity, intra-abdominal adhesion formation, tensile stress, stretchability, and degree of tissue ingrowth in terms of collagen deposition and neovascularization, P-SIS exhibits clear advantages over P-PC as well as P-ADM after large abdominal wall defect reconstruction.

  12. Role of microRNA 1207-5P and its host gene, the long non-coding RNA Pvt1, as mediators of extracellular matrix accumulation in the kidney: implications for diabetic nephropathy.

    Alvarez, M Lucrecia; Khosroheidari, Mahdieh; Eddy, Elena; Kiefer, Jeff


    Diabetic nephropathy is the most common cause of chronic kidney failure and end-stage renal disease in the Western World. One of the major characteristics of this disease is the excessive accumulation of extracellular matrix (ECM) in the kidney glomeruli. While both environmental and genetic determinants are recognized for their role in the development of diabetic nephropathy, epigenetic factors, such as DNA methylation, long non-coding RNAs, and microRNAs, have also recently been found to underlie some of the biological mechanisms, including ECM accumulation, leading to the disease. We previously found that a long non-coding RNA, the plasmacytoma variant translocation 1 (PVT1), increases plasminogen activator inhibitor 1 (PAI-1) and transforming growth factor beta 1 (TGF-β1) in mesangial cells, the two main contributors to ECM accumulation in the glomeruli under hyperglycemic conditions, as well as fibronectin 1 (FN1), a major ECM component. Here, we report that miR-1207-5p, a PVT1-derived microRNA, is abundantly expressed in kidney cells, and is upregulated by glucose and TGF-β1. We also found that like PVT1, miR-1207-5p increases expression of TGF-β1, PAI-1, and FN1 but in a manner that is independent of its host gene. In addition, regulation of miR-1207-5p expression by glucose and TGFβ1 is independent of PVT1. These results provide evidence supporting important roles for miR-1207-5p and its host gene in the complex pathogenesis of diabetic nephropathy.

  13. Matriz de indicadores de sustentabilidade para a gestão de resíduos sólidos urbanos Matrix of sustainability indicatorsfor the urban solid waste management

    Leila Santos Santiago


    Full Text Available O artigo apresenta uma matriz de indicadores de sustentabilidade para a gestão de resíduos sólidos urbanos e a forma de sua construção. A construção foi realizada baseando-se em informações adquiridas em referências nacionais e internacionais. Os indicadores foram organizados em uma matriz preliminar, a qual passou por um processo de validação externa, com especialistas, por meio do método Delphi. Para a realização deste método foram necessárias duas rodadas. A matriz final possui 6 dimensões de sustentabilidade: política, tecnológica, econômica/financeira, ambiental/ecológica, conhecimento e inclusão social, contemplando 42 indicadores e 126 descritores. A matriz elaborada poderá ser utilizada como instrumento de avaliação e planejamento da gestão dos resíduos sólidos em municípios.This paper presents a matrix of Sustainability Indicators for the Urban Solid Waste Management and the way of its construction. The construction was performed based on information acquired in national and international references. The indicators were organized into a primary matrix, which has gone an external validation process, with experts through the Delphi method. To perform this method two rounds were necessary. The final matrix has 6 dimensions of sustainability: politics, technology, economic/financial, environmental/ecological, knowledge and social inclusion, comprising 42 indicators, 126 descriptors. The matrix produced can be used as a tool for evaluation and planning of the solid waste management in municipalities.

  14. Multispin correlations and pseudo-thermalization of the transient density matrix in solid-state NMR: free induction decay and magic echo

    Morgan, Steven W.; Oganesyan, Vadim; Boutis, Gregory S.


    Quantum unitary evolution typically leads to thermalization of generic interacting many-body systems. There are very few known general methods for reversing this process, and we focus on the magic echo, a radio-frequency pulse sequence known to approximately “rewind” the time evolution of dipolar coupled homonuclear spin systems in a large magnetic field. By combining analytic, numerical, and experimental results we systematically investigate factors leading to the degradation of magic echoes, as observed in reduced revival of mean transverse magnetization. Going beyond the conventional analysis based on mean magnetization we use a phase encoding technique to measure the growth of spin correlations in the density matrix at different points in time following magic echoes of varied durations and compare the results to those obtained during a free induction decay (FID). While considerable differences are documented at short times, the long-time behavior of the density matrix appears to be remarkably universal among the types of initial states considered – simple low order multispin correlations are observed to decay exponentially at the same rate, seeding the onset of increasingly complex high order correlations. This manifestly athermal process is constrained by conservation of the second moment of the spectrum of the density matrix and proceeds indefinitely, assuming unitary dynamics. PMID:23710125

  15. Methodical evaluation and improvement of matrix compatible PDMS-overcoated coating for direct immersion solid phase microextraction gas chromatography (DI-SPME-GC)-based applications.

    Souza-Silva, Érica A; Gionfriddo, Emanuela; Shirey, Robert; Sidisky, Len; Pawliszyn, Janusz


    The main quest for the implementation of direct SPME to complex matrices has been the development of matrix compatible coatings that provide sufficient sensitivity towards the target analytes. In this context, we present here a thorough evaluation of PDMS-overcoated fibers suitable for simultaneous extraction of different polarities analytes, while maintaining adequate matrix compatibility. For this, eleven analytes were selected, from various application classes (pesticides, industrial chemicals and pharmaceuticals) and with a wide range of log P values (ranging from 1.43 to 6). The model matrix chosen was commercial Concord grape juice, which is rich in pigments such as anthocyanins, and contains approximately 20% of sugar (w/w). Two types of PDMS, as well as other intrinsic factors associated with the PDMS-overcoated fiber fabrication are studied. The evaluation showed that the PDMS-overcoated fibers considerably slowed down the coating fouling process during direct immersion in complex matrices of high sugar content. Longevity differences could be seen between the two types of PDMS tested, with a proprietary Sylgard(®) giving superior performance because of lesser amount of reactive groups and enhanced hydrophobicity. Conversely, the thickness of the outer layer did not seem to have a significant effect on the fiber lifetime. We also demonstrate that the uniformity of the overcoated PDMS layer is paramount to the achievement of reliable data and extended fiber lifetime. Employing the optimum overcoated fiber, limits of detection (LOD) in the range of 0.2-1.3 ng/g could be achieved. Additional improvement is attainable by introducing washing of the coatings after desorption, so that any carbon build-up (fouling) left on the coating surface after thermal desorption can be removed.

  16. Matrix theory

    Franklin, Joel N


    Mathematically rigorous introduction covers vector and matrix norms, the condition-number of a matrix, positive and irreducible matrices, much more. Only elementary algebra and calculus required. Includes problem-solving exercises. 1968 edition.

  17. Can matrix solid phase dispersion (MSPD) be more simplified? Application of solventless MSPD sample preparation method for GC-MS and GC-FID analysis of plant essential oil components.

    Wianowska, Dorota; Dawidowicz, Andrzej L


    This paper proposes and shows the analytical capabilities of a new variant of matrix solid phase dispersion (MSPD) with the solventless blending step in the chromatographic analysis of plant volatiles. The obtained results prove that the use of a solvent is redundant as the sorption ability of the octadecyl brush is sufficient for quantitative retention of volatiles from 9 plants differing in their essential oil composition. The extraction efficiency of the proposed simplified MSPD method is equivalent to the efficiency of the commonly applied variant of MSPD with the organic dispersing liquid and pressurized liquid extraction, which is a much more complex, technically advanced and highly efficient technique of plant extraction. The equivalency of these methods is confirmed by the variance analysis. The proposed solventless MSPD method is precise, accurate, and reproducible. The recovery of essential oil components estimated by the MSPD method exceeds 98%, which is satisfactory for analytical purposes.

  18. Matrix-assisted laser desorption/ionization mass spectrometric analysis of poly(3,4-ethylenedioxythiophene) in solid-state dye-sensitized solar cells: comparison of in situ photoelectrochemical polymerization in aqueous micellar and organic media.

    Zhang, Jinbao; Ellis, Hanna; Yang, Lei; Johansson, Erik M J; Boschloo, Gerrit; Vlachopoulos, Nick; Hagfeldt, Anders; Bergquist, Jonas; Shevchenko, Denys


    Solid-state dye-sensitized solar cells (sDSCs) are devoid of such issues as electrolyte evaporation or leakage and electrode corrosion, which are typical for traditional liquid electrolyte-based DSCs. Poly(3,4-ethylenedioxythiophene) (PEDOT) is one of the most popular and efficient p-type conducting polymers that are used in sDSCs as a solid-state hole-transporting material. The most convenient way to deposit this insoluble polymer into the dye-sensitized mesoporous working electrode is in situ photoelectrochemical polymerization. Apparently, the structure and the physicochemical properties of the generated conducting polymer, which determine the photovoltaic performance of the corresponding solar cell, can be significantly affected by the preparation conditions. Therefore, a simple and fast analytical method that can reveal information on polymer chain length, possible chemical modifications, and impurities is strongly required for the rapid development of efficient solar energy-converting devices. In this contribution, we applied matrix-assisted laser desorption/ionization mass spectrometry (MALDI MS) for the analysis of PEDOT directly on sDSCs. It was found that the PEDOT generated in aqueous micellar medium possesses relatively shorter polymeric chains than the PEDOT deposited from an organic medium. Furthermore, the micellar electrolyte promotes a transformation of one of the thiophene terminal units to thiophenone. The introduction of a carbonyl group into the PEDOT molecule impedes the growth of the polymer chain and reduces the conductivity of the final polymer film. Both the simplicity of sample preparation (only application of the organic matrix onto the solar cell is needed) and the rapidity of analysis hold the promise of making MALDI MS an essential tool for the physicochemical characterization of conducting polymer-based sDSCs.

  19. The stability of non-ionic surfactants and linear alkylbenzene sulfonates in a water matrix and on solid-phase extraction cartridges.

    Petrović, M; Barceló, D


    The stability of nonylphenol ethoxylates (NPEO), alcohol ethoxylates (AEO), coconut diethanol amides (CDEA) and linear alkylbenzene sulfonates (LAS) in a water matrix and preconcentrated on SPE cartridges was studied. A stability study was carried out in a water matrix (spiked ground water and real-world waste water) comparing different pretreatment procedures (addition of sulfuric acid to pH = 3, preservation with 1% and 3% of formaldehyde). When stored in a water matrix serious qualitative and quantitative changes occurred in waste water during the period of time studied (30 days). The losses of C12-C14 alcohol ethoxylates ranged from 72% to 88% when the sample was preserved with acid and from 17% to 86% when the sample was preserved with formaldehyde (3%). Simultaneously, an enrichment of the shorter alkyl chain homologues (C7EO and C10EO) was observed. The losses of NPEO were from 45% (sample preserved by acidification or by addition of 3% of formaldehyde) to 85% (sample preserved with 1% of formaldehyde). Additionally, an increase in concentration of polyethylene glycols (PEGs) and formation of different acidic forms, such as monocarboxylated (MCPEGs) and dicarboxylated polyethylene glycols (DCPEGs) were observed. The stability of surfactants preconcentrated on SPE cartridges was studied as a function of storage time and storage conditions (room temperature, 4 degrees C and -20 degrees C). The results indicate that disposable SPE cartridges can be recommended for the stabilization of non-ionic surfactants and LAS. Storage at -20 degrees C is feasible for long periods (up to 3 months for ground water and up to 2 months for waste water), while storage at 4 C can be recommended for a maximum of 1 month. When cartridges were kept at -20 degrees C the losses of AEOs (n = 12, 13 and 14), preconcentrated from waste water, ranged from 17 to 29% (after 60 days) and other compounds suffered small losses (maximum of 14% for C13LAS). At room temperature, after 7 days, the

  20. Multiresidue LC-MS/MS analysis of cephalosporins and quinolones in milk following ultrasound-assisted matrix solid-phase dispersive extraction combined with the quick, easy, cheap, effective, rugged, and safe methodology.

    Karageorgou, Eftichia; Myridakis, Antonis; Stephanou, Euripides G; Samanidou, Victoria


    A sensitive and selective confirmatory method for milk-residue analysis of ten quinolones and eight cephalosporins by LC-MS/MS has been developed herein. For the chromatographic separation of target analytes, a Perfectsil ODS-2 (250 × 4 mm, 5 μm) analytical column was used and gradient elution was applied, using a mobile phase of 0.1% w/w TFA in water and 0.1% w/w TFA in ACN. Ultrasound-assisted matrix solid-phase dispersion procedure was applied for the extraction and clean-up procedure of antimicrobials agents from milk matrix using a mixture of Bond Elut Plexa sorbent and QuEChERS. The method was validated meeting the European Legislation determining selectivity, linearity response, trueness, precision (repeatability and between-day reproducibility), decision limit, detection capability, and ruggedness following the Youden approach. Recoveries of all antibiotics ranged from 81.7 to 117.9%, while RSD values were lower than 13.7%. Limits of quantification for all examined compounds ranged from 2.4 to 15.0 μg/kg, substantially lower than the maximum residue limits established by the European Union (30-100 μg/kg).

  1. Determination of polybrominated diphenyl ethers in fish tissues by matrix solid-phase dispersion and gas chromatography coupled to triple quadrupole mass spectrometry: case study on European eel (Anguilla anguilla) from Mediterranean coastal lagoons.

    Labadie, Pierre; Alliot, Fabrice; Bourges, Catherine; Desportes, Annie; Chevreuil, Marc


    This paper describes the development and validation of an analytical methodology to determine 28 polybrominated diphenyl ethers (PBDEs) in European eel (Anguilla anguilla) tissues using matrix solid-phase dispersion (MSPD) and gas chromatography coupled to triple quadrupole mass spectrometry (GC-QQQ-MS/MS). A total of 28 PBDEs were targeted, including tri- to deca-brominated congeners. The robustness and effectiveness of the proposed sample preparation procedure was demonstrated in lipid-rich eel tissues. The use of batch MSPD with activated silica gel and H(2)SO(4)-impregnated silica gel, followed by H(2)SO(4) digestion and multilayer cartridge clean-up allowed for complete lipid removal and eliminated matrix effects during GC-QQQ-MS/MS analysis. The average PBDE recoveries from eel muscle samples spiked with PBDEs at two levels were in the range 56.2-119.0%. Precision was satisfactory since relative standard deviations were lower than 19.6%, regardless of spike level, and method quantification limits ranged between 1 and 170 pg g(-1) (wet weight). The method demonstrated its successful application for the analysis of eel samples from two coastal lagoons located on the western French Mediterranean coast. All samples tested positive, but for tri- to hexa-brominated congeners only and total PBDE levels observed in this study were in the range 0.08-1.80 ng g(-1) wet weight.

  2. A combination of solid-phase extraction and dispersive solid-phase extraction effectively reduces the matrix interference in liquid chromatography-ultraviolet detection during pyraclostrobin analysis in perilla leaves.

    Farha, Waziha; Rahman, Md Musfiqur; Abd El-Aty, A M; Jung, Da-I; Kabir, Md Humayun; Choi, Jeong-Heui; Kim, Sung-Woo; Im, So Jeong; Lee, Young-Jun; Shin, Ho-Chul; Kwon, Chan-Hyeok; Son, Young-Wook; Lee, Kang-Bong; Shim, Jae-Han


    Perilla leaves contain many interfering substances; thus, it is difficult to protect the analytes during identification and integration. Furthermore, increasing the amount of sample to lower the detection limit worsens the situation. To overcome this problem, we established a new method using a combination of solid-phase extraction and dispersive solid-phase extraction to analyze pyraclostrobin in perilla leaves by liquid chromatography with ultraviolet absorbance detection. The target compound was quantitated by external calibration with a good determination coefficient (R(2) = 0.997). The method was validated (in triplicate) with three fortification levels, and 79.06- 89.10% of the target compound was recovered with a relative standard deviation <4. The limits of detection and quantification were 0.0033 and 0.01 mg/kg, respectively. The method was successfully applied to field samples collected from two different areas at Gwangju and Muan. The decline in the resiudue concentrations was best ascribed to a first-order kinetic model with half-lives of 5.7 and 4.6 days. The variation between the patterns was attributed to humidity.

  3. Novel molecularly imprinted polymers with carbon nanotube as matrix for selective solid-phase extraction of emodin from kiwi fruit root.

    Yang, Xiao; Zhang, Zhaohui; Li, Jiaxing; Chen, Xing; Zhang, Minlei; Luo, Lijuan; Yao, Shouzhuo


    In this paper, we present a novel surface imprinting technique for the preparation of molecularly imprinted polymers/multi-walled carbon nanotubes (MIPs/MWNTs) for extraction of emodin from kiwi fruit root. The MIPs/MWNTs were characterised by scanning electron microscopy (SEM) and Fourier transform-infrared spectroscopy (FT-IR). The properties involving adsorption dynamics, static adsorption, and selective recognition capacity were evaluated. The MIPs/MWNTs exhibited good site accessibility in which it only took 60 min to achieve adsorption equilibrium and highly selective recognition for the template emodin. Furthermore, the performance of the MIPs/MWNTs as solid phase extraction (SPE) material was investigated in detail. The proposed MIPs/MWNTs-SPE procedure for emodin exhibited satisfactory recoveries ranging from 89.2% to 93.8% for real samples. It was used for the purification and enrichment of emodin from kiwi fruit root successfully.

  4. Simplified miniaturized ultrasound-assisted matrix solid phase dispersion extraction and high performance liquid chromatographic determination of seven flavonoids in citrus fruit juice and human fluid samples: hesperetin and naringenin as biomarkers.

    Barfi, Behruz; Asghari, Alireza; Rajabi, Maryam; Barfi, Azadeh; Saeidi, Iman


    In the present study, for the first time, a simplified miniaturized ultrasound-assisted matrix solid-phase dispersion (SM-USA-MSPD) method with a different application for liquid matrices was developed to extract different flavonoids (hesperidin, diosmin, eriocitrin, narirutin, naringin, hesperetin and naringenin) from citrus fruit juice and human fluid samples prior to their determination using high performance liquid chromatography (HPLC). Different effective parameters were studied and under the optimum conditions (including sample volume: 150μL; solid phase: silica-based C18, 200mg; eluting solvent: methanol, 500μL; pH: 4; and sonication: 6min; at room temperature), limits of detection and limits of quantification were ranged from 23.3 to 46.8ngmL(-1) and 74.8 to 141.5ngmL(-1), respectively. Once optimized, analytical performance of the method was studied in terms of linearity (0.074-198.5μgmL(-1), r(2)>0.991), accuracy (recovery=84.6-101.5%), and precision (repeatability: intra-day precisionjuices- and the obtained results confirmed that these compounds could be used as good biomarkers of citrus fruit juice intake.

  5. Microcrystalline cellulose based matrix solid phase dispersion microextration for isomeric triterpenoid acids in loquat leaves by ultrahigh-performance liquid chromatography and quadrupole time-of-flight mass spectrometry.

    Cao, Jun; Peng, Li-Qing; Xu, Jing-Jing


    An analytical procedure based on matrix solid phase dispersion (MSPD) microextration and ultrahigh-performance liquid chromatography coupled with quadrupole time-of-flight tandem mass spectrometry was developed for the determination of isomeric triterpenoid acids (maslinic acid, corosolic acid, oleanolic acid and ursolic acid) in loquat leaves. Microcrystalline cellulose was used for the first time as a solid sorbent in MSPD microextration. Compared with the traditional extraction methods, the proposed method possessed the advantages of shorter extraction time, and lower consumption of sample, sorbent and organic solvent. The MSPD parameters that influenced the extraction efficiency of isomeric analytes were investigated and optimized in detail. Under the optimized conditions, good linearity was obtained with correlation coefficients higher than 0.9990. The limits of detection and quantification were 19.6-51.6μg/kg and 65.3-171.8μg/kg, respectively. Meanwhile, the recoveries obtained for all the analytes were ranging from 90.1% to 107.5%. Finally, the optimized method was successfully applied for analyzing these isomeric acids in loquat leaves samples obtained from different cultivated areas.

  6. Rheocasting Al Matrix Composites

    Girot, F. A.; Albingre, L.; Quenisset, J. M.; Naslain, R.


    Aluminum alloy matrix composites reinforced by SiC short fibers (or whiskers) can be prepared by rheocasting, a process which consists of the incorporation and homogeneous distribution of the reinforcement by stirring within a semi-solid alloy. Using this technique, composites containing fiber volume fractions in the range of 8-15%, have been obtained for various fibers lengths (i.e., 1 mm, 3 mm and 6 mm for SiC fibers). This paper attempts to delineate the best compocasting conditions for aluminum matrix composites reinforced by short SiC (e.g Nicalon) or SiC whiskers (e.g., Tokamax) and characterize the resulting microstructures.

  7. Novel Transparent Phosphor Conversion Matrix with High Thermal Conductivity for Next Generation Phosphor-Converted LED-based Solid State Lighting

    Bockstaller, Michael [Carnegie Mellon Univ., Pittsburgh, PA (United States)


    The low thermal conductivity of state-of-the-art polymer encapsulants (k ~ 0.15 Wm-1K-1) limits the efficiency and power density of current phosphor conversion light emitting diodes (pc-LEDs). The technical objective of this project was to demonstrate synthesis and processing schemes for the fabrication of polymer hybrid encapsulants with a thermal conductivity exceeding k = 0.4 Wm-1K-1 for LED applications. The ‘hybrid polymer’ approach encompasses the dispersion of high thermal conductivity particle fillers (zinc oxide, ZnO as well as the alpha-polymorph of alumina, Al2O3) within a polysiloxane matrix (poly(dimethylsiloxane), PDMS as well as poly(phenyl methyl siloxane), PPMS) to increase the thermal conductivity while maintaining optical transparency and photothermal stability at levels consistent with LED applications. To accomplish this goal, a novel synthesis method for the fabrication of nanosized ZnO particles was developed and a novel surface chemistry was established to modify the surface of zinc oxide particle fillers and thus to enable their dispersion in poly(dimethyl siloxane) (PDMS) matrix polymers. Molecular dynamics and Mie simulations were used to optimize ligand structure and to enable the concurrent mixing of particles in PDMS/PPMS embedding media while also minimizing the thermal boundary resistance as well as optical scattering of particle fillers. Using this approach the synthesis of PDMS/ZnO hybrid encapsulants exhibiting a thermal conductivity of 0.64 Wm-1K-1 and optical transparency > 0.7 mm-1 was demonstrated. A forming process based on micromolding was developed to demonstrate the forming of particle filled PDMS into film and lens shapes. Photothermal stability testing revealed stability of the materials for approximately 4000 min when exposed to blue light LED (450 nm, 30 W/cm2). One postgraduate and seven graduate students were supported by the project. The research performed within this project led to fifteen publications in peer

  8. Multi-residue analysis of pharmaceuticals in aqueous environmental samples by online solid-phase extraction-ultra-high-performance liquid chromatography-tandem mass spectrometry: optimisation and matrix effects reduction by quick, easy, cheap, effective, rugged and safe extraction.

    Bourdat-Deschamps, Marjolaine; Leang, Sokha; Bernet, Nathalie; Daudin, Jean-Jacques; Nélieu, Sylvie


    The aim of this study was to develop and optimise an analytical method for the quantification of a bactericide and 13 pharmaceutical products, including 8 antibiotics (fluoroquinolones, tetracyclines, sulfonamides, macrolide), in various aqueous environmental samples: soil water and aqueous fractions of pig slurry, digested pig slurry and sewage sludge. The analysis was performed by online solid-phase extraction coupled to ultra-high performance liquid chromatography with tandem mass spectrometry (online SPE-UHPLC-MS-MS). The main challenge was to minimize the matrix effects observed in mass spectrometry, mostly due to ion suppression. They depended on the dissolved organic carbon (DOC) content and its origin, and ranged between -22% and +20% and between -38% and -93% of the signal obtained without matrix, in soil water and slurry supernatant, respectively. The very variable levels of these matrix effects suggested DOC content cut-offs above which sample purification was required. These cut-offs depended on compounds, with concentrations ranging from 30 to 290mgC/L for antibiotics (except tylosine) up to 600-6400mgC/L for the most apolar compounds. A modified Quick, Easy, Cheap, Effective, Rugged and Safe (QuEChERS) extraction procedure was therefore optimised using an experimental design methodology, in order to purify samples with high DOC contents. Its performance led to a compromise, allowing fluoroquinolone and tetracycline analysis. The QuEChERS extraction salts consisted therefore of sodium acetate, sodium sulfate instead of magnesium sulfate, and sodium ethylenediaminetetraacetate (EDTA) as a ligand of divalent cations. The modified QuEChERS procedure employed for the extraction of pharmaceuticals in slurry and digested slurry liquid phases reduced the matrix effects for almost all the compounds, with extraction recoveries generally above 75%. The performance characteristics of the method were evaluated in terms of linearity, intra-day and inter

  9. Determination of solid solubility level of Ho nanoparticles in Y-123 superconducting matrix and strong Cu{sub 1} site preference of nanoparticles

    Sarıtekin, N.K. [Abant Izzet Baysal University, Department of Physics, Bolu 14280 (Turkey); Zalaoglu, Y., E-mail: [Abant Izzet Baysal University, Department of Physics, Bolu 14280 (Turkey); Osmaniye Korkut Ata University, Department of Physics, Osmaniye 80000 (Turkey); Yildirim, G. [Abant Izzet Baysal University, Department of Mechanical Engineering, Bolu 14280 (Turkey); Doğruer, M.; Terzioglu, C.; Varilci, A.; Gorur, O. [Abant Izzet Baysal University, Department of Physics, Bolu 14280 (Turkey)


    Graphical abstract: The excess Ho particles inserted in the Y-123 superconducting matrix not only damage the crystal plane alignments and crystallinity of poly-crystallized Y-123 bulk samples but also lead to the phase transition from optimally doped state to the underdoped position in the crystal structure. - Highlights: • Identification of Y-123 ceramics by ρ–T, J{sub c}, XRD, SEM, EDX, H{sub V} and density measurements. • Optimum dopant level of x = 0.100 for Ho concentration in the Y-123 crystal structure. • Phase transition from optimally doped to the underdoped position with excess Ho impurities (x > 0.100). • Improvement of mechanical behavior with increase in strength of interaction between grains. • Superiority of IIC model to HK approach for the description of the real microhardness values. - Abstract: This comprehensive study reports the effect of the Ho inclusions on the microstructural, electrical, mechanical and superconducting characteristics of YBa{sub 2}Cu{sub 3}O{sub 7−δ} ceramic superconductors with the aid of standard characterization methods including the bulk density, dc resistivity (ρ–T), transport critical current density (J{sub c}), X-ray diffraction (XRD), electron dispersive X-ray (EDX), scanning electron microscopy (SEM) and Vickers microhardness (H{sub V}) investigations. The experimental results such as the degree of granularity, hole (filling) localization effect, room temperature resistivity, onset–offset critical transition temperature, degree of the broadening, thermodynamic fluctuations (spin-gap opening temperature), crystallinity, crystal plane alignments (texturing), crystal structure, grain size, phase purity and lattice parameters, appearance of flux pinning centers, grain boundary weak-links (interaction between the superconducting grains), surface morphologies (grain size distribution), real (load independent) microhardness values, elemental compositions and distributions belonging to the pure and Y

  10. In matrix derivatization of trichloroethylene metabolites in human plasma with methyl chloroformate and their determination by solid-phase microextraction-gas chromatography-electron capture detector.

    Mudiam, Mohana Krishna Reddy; Jain, Rajeev; Varshney, Meenu; Ch, Ratnasekhar; Chauhan, Abhishek; Goyal, Sudhir Kumar; Khan, Haider A; Murthy, R C


    Trichloroethylene (TCE) is a common industrial chemical that has been widely used as metal degreaser and for many industrial purposes. In humans, TCE is metabolized into dichloroacetic acid (DCA), trichloroacetic acid (TCA) and trichloroethanol (TCOH). A simple and rapid method has been developed for the quantitative determination of TCE metabolites. The procedure involves the in situ derivatization of TCE metabolites with methyl chloroformate (MCF) directly in diluted plasma samples followed by extraction and analysis with solid-phase microextraction (SPME) coupled to gas chromatography-electron capture detector (GC-ECD). Factors which can influence the efficiency of derivatization such as amount of MCF and pyridine (PYR), ratio of water/methanol were optimized. The factors which can affect the extraction efficiencies of SPME were screened using 2(7-4) Placket-Burman Design (PBD). A central composite design (CCD) was then applied to further optimize the most significant factors for optimum SPME extraction. The optimum factors for the SPME extraction were found to be 562.5mg of NaCl, pH at 1 and an extraction time of 22 min. Recoveries and detection limits of all three analytes in plasma were found to be in the range of 92.69-97.55% and 0.036-0.068 μg mL(-1) of plasma, respectively. The correlation coefficients were found to be in the range of 0.990-0.995. The intra- and inter-day precisions for TCE metabolites were found to be in the range of 2.37-4.81% and 5.13-7.61%, respectively. The major advantage of this method is that MCF derivatization allows conversion of TCE metabolites into their methyl esters in very short time (≤30 s) at room temperature directly in the plasma samples, thus makes it a solventless analysis. The method developed was successfully applied to the plasma samples of humans exposed to TCE.

  11. Matrix Factorization and Matrix Concentration

    Mackey, Lester


    Motivated by the constrained factorization problems of sparse principal components analysis (PCA) for gene expression modeling, low-rank matrix completion for recommender systems, and robust matrix factorization for video surveillance, this dissertation explores the modeling, methodology, and theory of matrix factorization.We begin by exposing the theoretical and empirical shortcomings of standard deflation techniques for sparse PCA and developing alternative methodology more suitable for def...

  12. Preparation of magnetic graphene/mesoporous silica composites with phenyl-functionalized pore-walls as the restricted access matrix solid phase extraction adsorbent for the rapid extraction of parabens from water-based skin toners.

    Feng, Jianan; He, Xinying; Liu, Xiaodan; Sun, Xueni; Li, Yan


    In this work, phenyl-functionalized magnetic graphene/mesoporous silica composites (MG-mSiO2-Ph) were prepared and applied as restricted access matrix solid phase extraction (RAM-SPE) adsorbents to determine the parabens in commercially available retail cosmetics. MG-mSiO2-Ph composites were synthesized by a surfactant-mediated co-condensation reaction in which mesoporous silica with phenyl-functionalized pore-walls was coated on a magnetic graphene sheet. The obtained nano-composites were proven to be of sufficient quality for an ideal RAM-SPE adsorbent with a large specific surface area of 369m(2)g(-1), uniform mesopores of 2.8nm, and special phenyl-functionalized pore-walls. Parabens, such as methyl paraben, ethyl paraben and propyl paraben, were extracted from water-based skin toners using one step of the RAM-SPE and were then analysed by a HPLC-DAD system. The SPE conditions were optimized by studying the parameters, such as the adsorbent amount, elution solvent type, adsorption time and desorption time, that influence the extraction efficiency. For each analyte, there were good linearities of approximately 0.10-120μgmL(-1) with determination coefficients (R(2))>0.995. The sensitivity was as low as 0.01-0.025μgmL(-1) for the LOD, and the percent recoveries were 98.37-105.84%. The intra-day and inter-day RSDs were 1.44-6.11% (n=6) and 3.12-11.70% (n=6), respectively. The results indicated that this method with novel RAM-SPE adsorbents is sensitive and convenient. The results also offered an attractive alternative for the extraction and determination of paraben preservatives in a complex matrix, such as cosmetics. Copyright © 2016 Elsevier B.V. All rights reserved.

  13. Matrix calculus

    Bodewig, E


    Matrix Calculus, Second Revised and Enlarged Edition focuses on systematic calculation with the building blocks of a matrix and rows and columns, shunning the use of individual elements. The publication first offers information on vectors, matrices, further applications, measures of the magnitude of a matrix, and forms. The text then examines eigenvalues and exact solutions, including the characteristic equation, eigenrows, extremum properties of the eigenvalues, bounds for the eigenvalues, elementary divisors, and bounds for the determinant. The text ponders on approximate solutions, as well

  14. Thermal-cycling-induced spectral diffusion and thermal barriers in anisole-doped cyclohexane, an unusual multiphase host-guest system.

    Somoza, Mark M; Friedrich, Josef


    The host-guest system of anisole incorporated into a cyclohexane matrix was investigated in a series of hole-burning experiments. This system is unusual in that cyclohexane can freeze into coexisting solid phases. The hole-burning experiments support the existence of two crystalline phases and one disordered phase. A second surprising characteristic of this system is that the quasi-line absorption features of the spectra appear inverted at low temperature because of unexpected dominance of fluorescence and phosphorescence.

  15. Graphene/TiO2 nanocomposite based solid-phase extraction and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry for lipidomic profiling of avocado (Persea americana Mill.).

    Shen, Qing; Yang, Mei; Li, Linqiu; Cheung, Hon-Yeung


    Phospholipids possess important physiological, structural and nutritional functions in biological systems. This study described a solid-phase extraction (SPE) method, employing graphene and titanium dioxide (G/TiO2) nanocomposite as sorbent, for the selective isolation and enrichment of phospholipids from avocado (Persea americana Mill.). Based on the principal that the phosphoryl group in the phospholipid can interact with TiO2 via a bridging bidentate mode, an optimum condition was established for SPE, and was successfully applied to prepare avocado samples. The extracts were monitored by matrix-assisted laser desorption ionization time-of-flight/tandem mass spectrometry (MALDI-TOF/MS) in both positive-ion and negative-ion modes. Results showed that phospholipids could be efficiently extracted in a clean manner by G/TiO2 based SPE. In addition, the signals of phospholipids were enhanced while the noise was reduced. Some minor peaks became more obvious. In conclusion, the nanocomposite material of G/TiO2 was proved to be a promising sorbent for selective separation of phospholipids from crude lipid extract.

  16. Importance of the coupling between the sign of the mean stress and the third invariant on the rate of void growth and collapse in porous solids with a von Mises matrix

    Alves, J. L.; Revil-Baudard, Benoit; Cazacu, Oana


    Recently, Cazacu et al (2013a J. Appl. Mech. 80 64501) demonstrated that the plastic potential of porous solids with a von Mises matrix containing randomly distributed spherical cavities should involve a very specific coupling between the mean stress and J_{3}^{\\Sigma} , the third invariant of the stress deviator. In this paper, the effects of this coupling on void evolution are investigated. It is shown that the new analytical model predicts that for axisymmetric stress states, void growth is faster for loading histories corresponding to J_{3}^{\\Sigma} \\ge 0 than for those corresponding to J_{3}^{\\Sigma} \\le 0 . However, void collapse occurs faster for loadings where J_{3}^{\\Sigma} \\le 0 than for those characterized by J_{3}^{\\Sigma} \\ge 0 . Finite-element (FE) results also confirm these trends. Furthermore, comparisons between FE results and corresponding predictions of yielding and void evolution show the improvements provided by the new model with respect to Gurson's. Irrespective of the loading history, the predicted rate of void growth is much faster than that according to Gurson's criterion.

  17. Direct analysis of 18 flavonol glycosides, aglycones and terpene trilactones in Ginkgo biloba tablets by matrix solid phase dispersion coupled with ultra-high performance liquid chromatography tandem triple quadrupole mass spectrometry.

    Liu, Xin-Guang; Yang, Hua; Cheng, Xiao-Lan; Liu, Lei; Qin, Yong; Wang, Qi; Qi, Lian-Wen; Li, Ping


    Analysis and quality control of Ginkgo biloba have been comprehensively studied. However, little attention has been devoted to the simultaneous extraction and analysis of flavonols and terpene trilactones, especially for direct quantification of flavonol glycosides. This work described a rapid strategy for one-step extraction and quantification of the components. A matrix solid phase dispersion (MSPD) method was designed for the extraction of ginkgo ingredients and compared with the heat-reflux and ultrasonic extraction methods. An ultra-high performance liquid chromatography (UHPLC)-tandem-triple-quadrupole-mass spectrometry (QQQ-MS) method was developed for detection of the 18 components, including 10 original flavonol glycosides, 3 aglycones, and 5 lactones. Subsequently, the proposed strategy was used for the analysis of 12 G. biloba tablets. Results showed that MSPD produced comparable extraction efficiency but consumed less time and required lower solvent volumes compared with conventional methods. Without hydrolysis, the concentration detected was much closer to the original in the sample. The total flavonol glycoside contents in ginkgo tablets ranged from 3.59 to 125.21μgmg(-1), and the terpene trilactone varied from 3.45 to 57.8μgmg(-1) among different manufacturers. In conclusion, the proposed MSPD and UHPLC-QQQ-MS is rapid and sensitive in providing comprehensive profile of chemical constituents especially the genuine flavonol glycosides for improved quality control of ginkgo products.

  18. Matrix Thermalization

    Craps, Ben; Nguyen, Kévin


    Matrix quantum mechanics offers an attractive environment for discussing gravitational holography, in which both sides of the holographic duality are well-defined. Similarly to higher-dimensional implementations of holography, collapsing shell solutions in the gravitational bulk correspond in this setting to thermalization processes in the dual quantum mechanical theory. We construct an explicit, fully nonlinear supergravity solution describing a generic collapsing dilaton shell, specify the holographic renormalization prescriptions necessary for computing the relevant boundary observables, and apply them to evaluating thermalizing two-point correlation functions in the dual matrix theory.

  19. Single-Drop Solution Electrode Discharge-Induced Cold Vapor Generation Coupling to Matrix Solid-Phase Dispersion: A Robust Approach for Sensitive Quantification of Total Mercury Distribution in Fish.

    Chen, Qian; Lin, Yao; Tian, Yunfei; Wu, Li; Yang, Lu; Hou, Xiandeng; Zheng, Chengbin


    Sensitive quantification of mercury distribution in fish is challenging because of insufficient sensitivities of conventional analytical methods, the limited mass of organs (tens of micrograms to several milligrams), and dilution of analyte concentration from sample digestion. In this work, a simple and robust approach coupling multiwall carbon nanotubes assisted matrix solid-phase dispersion (MWCNTs-MSPD) to single-drop solution electrode glow discharge-induced cold vapor generation (SD-SEGD-CVG) was developed for the sensitive determination of mercury in limited amount of sample. Mercury species contained in a limited amount of sample can be efficiently extracted into a 100 μL of eluent by MWCNTs-MSPD, which are conveniently converted to Hg(0) by SD-SEGD-CVG and further transported to atomic fluorescence spectrometry for their determination. Therefore, analyte dilution resulted from sample preparation is avoided and sensitivity is significantly improved. On the basis of consumption of 1 mg of sample, a limit of detection of 0.01 μg L(-1) (0.2 pg) was obtained with relative standard deviations (RSDs) of 5.2% and 4.6% for 2 and 20 μg L(-1), respectively. The accuracy of the proposed method was validated by analysis of three Certified Reference Materials with satisfying results. To confirm that SD-SEGD-CVG-AFS coupling to MWCNTs-MSPD is a promising method to quantify mercury distribution in fish, this method was successfully applied for the sensitive determination of mercury in seven organs of common carps (muscle, gill, intestine, liver, gallbladder, brain, and eye) after dietary of mercury species. The proposed method provides advantages of minimum sample dilution, low blank, high sample introduction efficiency, high sensitivity, and minimum toxic chemicals and sample consumption.

  20. Matrix inequalities

    Zhan, Xingzhi


    The main purpose of this monograph is to report on recent developments in the field of matrix inequalities, with emphasis on useful techniques and ingenious ideas. Among other results this book contains the affirmative solutions of eight conjectures. Many theorems unify or sharpen previous inequalities. The author's aim is to streamline the ideas in the literature. The book can be read by research workers, graduate students and advanced undergraduates.

  1. Synthesis and application of Fe3O4@SiO2@TiO2 for photocatalytic decomposition of organic matrix simultaneously with magnetic solid phase extraction of heavy metals prior to ICP-MS analysis.

    Habila, Mohamed A; ALOthman, Zeid A; El-Toni, Ahmed Mohamed; Labis, Joselito Puzon; Soylak, Mustafa


    Interference of organic compounds in the matrix of heavy metal solution could suppress their pre-concentration and detection processes. Therefore, this work aimed to develop simple and facile methods for separation of heavy metals before ICP-MS analysis. Fe3O4@SiO2@TiO2 core-double shell magnetic adsorbent was prepared and characterized by TEM, SEM, FTIR, XRD and surface area, and tested for Magnetic Solid Phase Extraction (MSPE) of Cu(II), Zn(II), Cd(II) and Pb(II). TEM micrograph of Fe3O4@SiO2@TiO2 reveals the uniform coating of TiO2 layer of about 20nm onto the Fe3O4@SiO2 nanoparticles and indicates that all nanoparticles are monodispersed and uniform. The saturation magnetization from the room-temperature hysteresis loops of Fe3O4 and Fe3O4@SiO2@TiO2 was found to be 72 and 40emug(-1), respectively, suggesting good separability of the nanoparticles. The Fe3O4@SiO2@TiO2 showed maximum adsorption capacity of 125, 137, 148 and 160mgg(-1) for Cu(II), Zn(II), Cd(II) and Pb(II) respectively, and the process was found to fit with the second order kinetic model and Langmuir isotherm. Fe3O4@SiO2@TiO2 showed efficient photocatalytic decomposition for tartrazine and sunset yellow (consider as Interfering organic compounds) in aqueous solution under the irradiation of UV light. The maximum recovery% was achieved at pH 5, by elution with 10mL of 2M nitric acid solution. The LODs were found to be 0.066, 0.049, 0.041 and 0.082µgL(-1) for Cu(II), Zn(II), Cd(II) and Pb(II), respectively while the LOQs were found to be 0.20, 0.15, 0.12 and 0.25µgL(-1) for Cu(II), Zn(II), Cd(II) and Pb(II), respectively. Copyright © 2016 Elsevier B.V. All rights reserved.

  2. Host thin films incorporating nanoparticles

    Qureshi, Uzma

    The focus of this research project was the investigation of the functional properties of thin films that incorporate a secondary nanoparticulate phase. In particular to assess if the secondary nanoparticulate material enhanced a functional property of the coating on glass. In order to achieve this, new thin film deposition methods were developed, namely use of nanopowder precursors, an aerosol assisted transport technique and an aerosol into atmospheric pressure chemical vapour deposition system. Aerosol assisted chemical vapour deposition (AACVD) was used to deposit 8 series of thin films on glass. Five different nanoparticles silver, gold, ceria, tungsten oxide and zinc oxide were tested and shown to successfully deposit thin films incorporating nanoparticles within a host matrix. Silver nanoparticles were synthesised and doped within a titania film by AACVD. This improved solar control properties. A unique aerosol assisted chemical vapour deposition (AACVD) into atmospheric pressure chemical vapour deposition (APCVD) system was used to deposit films of Au nanoparticles and thin films of gold nanoparticles incorporated within a host titania matrix. Incorporation of high refractive index contrast metal oxide particles within a host film altered the film colour. The key goal was to test the potential of nanopowder forms and transfer the suspended nanopowder via an aerosol to a substrate in order to deposit a thin film. Discrete tungsten oxide nanoparticles or ceria nanoparticles within a titanium dioxide thin film enhanced the self-cleaning and photo-induced super-hydrophilicity. The nanopowder precursor study was extended by deposition of zinc oxide thin films incorporating Au nanoparticles and also ZnO films deposited from a ZnO nanopowder precursor. Incorporation of Au nanoparticles within a VO: host matrix improved the thermochromic response, optical and colour properties. Composite VC/TiC and Au nanoparticle/V02/Ti02 thin films displayed three useful

  3. Treponema denticola interactions with host proteins

    J. Christopher Fenno


    Full Text Available Oral Treponema species, most notably T. denticola, are implicated in the destructive effects of human periodontal disease. Progress in the molecular analysis of interactions between T. denticola and host proteins is reviewed here, with particular emphasis on the characterization of surface-expressed and secreted proteins of T. denticola involved in interactions with host cells, extracellular matrix components, and components of the innate immune system.

  4. Matrix analysis

    Bhatia, Rajendra


    A good part of matrix theory is functional analytic in spirit. This statement can be turned around. There are many problems in operator theory, where most of the complexities and subtleties are present in the finite-dimensional case. My purpose in writing this book is to present a systematic treatment of methods that are useful in the study of such problems. This book is intended for use as a text for upper division and gradu­ ate courses. Courses based on parts of the material have been given by me at the Indian Statistical Institute and at the University of Toronto (in collaboration with Chandler Davis). The book should also be useful as a reference for research workers in linear algebra, operator theory, mathe­ matical physics and numerical analysis. A possible subtitle of this book could be Matrix Inequalities. A reader who works through the book should expect to become proficient in the art of deriving such inequalities. Other authors have compared this art to that of cutting diamonds. One first has to...

  5. Highly efficient direct aerobic oxidative esterification of cinnamyl alcohol with alkyl alcohols catalysed by gold nanoparticles incarcerated in a nanoporous polymer matrix: a tool for investigating the role of the polymer host.

    Buonerba, Antonio; Noschese, Annarita; Grassi, Alfonso


    The selective aerobic oxidation of cinnamyl alcohol to cinnamaldehyde, as well as direct oxidative esterification of this alcohol with primary and secondary aliphatic alcohols, were achieved with high chemoselectivity by using gold nanoparticles supported in a nanoporous semicrystalline multi-block copolymer matrix, which consisted of syndiotactic polystyrene-co-cis-1,4-polybutadiene. The cascade reaction that leads to the alkyl cinnamates occurs through two oxidation steps: the selective oxidation of cinnamyl alcohol to cinnamaldehyde, followed by oxidation of the hemiacetal that results from the base-catalysed reaction of cinnamaldehyde with an aliphatic alcohol. The rate constants for the two steps were evaluated in the temperature range 10-45 °C. The cinnamyl alcohol oxidation is faster than the oxidative esterification of cinnamaldehyde with methanol, ethanol, 2-propanol, 1-butanol, 1-hexanol or 1-octanol. The rate constants of the latter reaction are pseudo-zero order with respect to the aliphatic alcohol and decrease as the bulkiness of the alcohol is increased. The activation energy (Ea) for the two oxidation steps was calculated for esterification of cinnamyl alcohol with 1-butanol (Ea = 57.8±11.5 and 62.7±16.7 kJ mol(-1) for the first and second step, respectively). The oxidative esterification of cinnamyl alcohol with 2-phenylethanol follows pseudo-first-order kinetics with respect to 2-phenylethanol and is faster than observed for other alcohols because of fast diffusion of the aromatic alcohol in the crystalline phase of the support. The kinetic investigation allowed us to assess the role of the polymer support in the determination of both high activity and selectivity in the title reaction.

  6. Matrix pentagons

    Belitsky, A V


    The Operator Product Expansion for null polygonal Wilson loop in planar maximally supersymmetric Yang-Mills theory runs systematically in terms of multiparticle pentagon transitions which encode the physics of excitations propagating on the color flux tube ending on the sides of the four-dimensional contour. Their dynamics was unravelled in the past several years and culminated in a complete description of pentagons as an exact function of the 't Hooft coupling. In this paper we provide a solution for the last building block in this program, the SU(4) matrix structure arising from internal symmetry indices of scalars and fermions. This is achieved by a recursive solution of the Mirror and Watson equations obeyed by the so-called singlet pentagons and fixing the form of the twisted component in their tensor decomposition. The non-singlet, or charged, pentagons are deduced from these by a limiting procedure.

  7. Photoprocess of molecules encapsulated in porous solids X: Photosensitization of zeolite-Y encapsulated tris(2,2'-bipyridine-nickel-(II)ion by phenosafranine adsorbed onto the external surface of the nanoporous host

    Karuppannan Senthil Kumar; Sudha T; Paramasivam Natarajan


    Tris-(2,2'-bipyridine)-nickel-(II) complex ion encapsulated by zeolite-Y host has been synthesized by ship-in-a-bottle method. Photosensitization of nickel(II) complex (Ni(bpy)$^{2+}_{3}$) in the zeolite host by surface adsorbed phenosafranine dye was investigated by time-resolved fluorescence and absorption spectral measurements. Formation of nickel (II)-complex in the super cage of the host was ascertained by XRD, FTIR, solidstate NMR, diffuse reflectance UV-visible absorption spectroscopic techniques and ICP-OES measurements. Phenosafranine dye adsorbed on the external surface of zeolite-Y shows a decrease in fluorescence intensity with increased loading of the nickel(II) complex in zeolite-Y. Time-resolved emission studies show two excited state lifetimes for the photoexcited phenosafranine dye. Average fluorescence lifetimes of the dye in this case do not change with increase in the loading of the nickel(II) complex. However, relative contribution of short lifetime component increases when the amount of encapsulated nickel(II) complex is increased. The zeolite-Y host containing only bipyridyl ligand shows a marked decrease in fluorescence intensity. Fluorescence lifetimes of the dye however do not change with increased loading of bipyridyl while relative contribution of short lifetime component increases with an increase in the loading of bipyridyl in the host. This observation is interpreted to be due to electron transfer from the excited state of phenosafranine dye to the bipyridine. Picosecond pump-probe investigations confirm that the photoinduced electron transfer occurs from the surfaceadsorbed phenosafranine in the excited state to the nickel(II) complex within zeolite-Y cavity and also to the Ni(bpy)$^{2+}_{3}$ complex in contact with the phenosafranine dye co-adsorbed on the external surface of the host.

  8. Diversity of dynamics and morphologies of invasive solid tumors

    Yang Jiao


    Full Text Available Complex tumor-host interactions can significantly affect the growth dynamics and morphologies of progressing neoplasms. The growth of a confined solid tumor induces mechanical pressure and deformation of the surrounding microenvironment, which in turn influences tumor growth. In this paper, we generalize a recently developed cellular automaton model for invasive tumor growth in heterogeneous microenvironments [Y. Jiao and S. Torquato, PLoS Comput. Biol. 7, e1002314 (2011] by incorporating the effects of pressure. Specifically, we explicitly model the pressure exerted on the growing tumor due to the deformation of the microenvironment and its effect on the local tumor-host interface instability. Both noninvasive-proliferative growth and invasive growth with individual cells that detach themselves from the primary tumor and migrate into the surrounding microenvironment are investigated. We find that while noninvasive tumors growing in “soft” homogeneous microenvironments develop almost isotropic shapes, both high pressure and host heterogeneity can strongly enhance malignant behavior, leading to finger-like protrusions of the tumor surface. Moreover, we show that individual invasive cells of an invasive tumor degrade the local extracellular matrix at the tumor-host interface, which diminishes the fingering growth of the primary tumor. The implications of our results for cancer diagnosis, prognosis and therapy are discussed.


    Louis Dionissopoulos


    involved in Non-Specific Host Defense (NSHD, Remodeling or adaptation (RM and Immune Response (IR. Of the 49 genes tested by qRT-PCR, 9 (LCN2, MMP1, MUC16, GPX2, CSTA, FUT1, SERPINE2, BCAM, RAC3 were upregulated, 20 (MTOR, AKIRIN2, NFKBIZ, NFKB2, ACVR2A, LAMB1, FRS2, PPARD, LBP, NEDD4L, SGK1, DEDD2, MAP3K8, PARD6B, PLIN2, ADA, HPGD, FMO5, BMP6, TCHH were downregulated and 20 were unchanged due to butyrate administration in the proximal gastrointestinal tract. These results demonstrate the potential protective effect and molecular mechanisms involved in a novel butyrate treatment for inflammatory gastrointestinal conditions.

  10. Gastrointestinal mucormycosis in immunocompromised hosts.

    Dioverti, M Veronica; Cawcutt, Kelly A; Abidi, Maheen; Sohail, M Rizwan; Walker, Randall C; Osmon, Douglas R


    Invasive mucormycosis is a rare fungal infection in immunocompromised hosts, but it carries a high mortality rate. Primary gastrointestinal disease is the least frequent form of presentation. Early diagnosis and treatment are critical in the management; however, symptoms are typically non-specific in gastrointestinal disease, leading to delayed therapy. To describe the clinical presentation, diagnosis, treatment and outcomes of gastrointestinal mucormycosis in immunocompromised hosts, we reviewed all cases of primary gastrointestinal mucormycosis in immunocompromised hosts reported in English literature as well as in our Institution from January 1st 1991 to December 31st 2013 for a total of 31 patients. About 52% of patients underwent solid organ transplant (SOT), while the rest had an underlying haematologic malignancy. Abdominal pain was the most common presenting symptom, followed by gastrointestinal bleeding and fever. Gastric disease was more common in SOT, whereas those with haematologic malignancy presented with intestinal disease (P = 0.002). Although gastrointestinal mucormycosis remains an uncommon condition in immunocompromised hosts, it carries significant morbidity and mortality, particularly in cases with intestinal involvement. A high index of suspicion is of utmost importance to institute early and appropriate therapy and improve outcomes.

  11. Riemann Zeta Matrix Function

    Kargın, Levent; Kurt, Veli


    In this study, obtaining the matrix analog of the Euler's reflection formula for the classical gamma function we expand the domain of the gamma matrix function and give a infinite product expansion of sinπxP.  Furthermore we define Riemann zeta matrix function and evaluate some other matrix integrals. We prove a functional equation for Riemann zeta matrix function.

  12. Vibrational relaxation of guest and host in mixed molecular crystals

    Hill, Jeffrey R.; Chronister, Eric L.; Chang, Ta-Chau; Kim, Hackjin; Postlewaite, Jay C.; Dlott, Dana D.


    Vibrational relaxation (VR) of dilute impurity molecules (naphthalene, anthracene) in crystalline host matrices (durene, naphthalene) is studied with the ps photon echo technique. The results obtained by echoes on vibrations in the electronically excited state are compared to previous ps time delayed coherent Raman studies of ground state vibrations of the pure host matrix. The relaxation channels for guest and host, and the effects of molecular and crystal structure on VR rates are determined.

  13. Solid propellants.

    Marsh, H. E., Jr.; Hutchison, J. J.


    The basic principles underlying propulsion by rocket motor are examined together with the configuration of a solid propellant motor. Solid propellants and their preparation are discussed, giving attention to homogeneous propellants, composite propellants, energetic considerations in choosing a solid propellant, the processing of composite propellants, and some examples of new developments. The performance of solid propellants is investigated, taking into account characteristics velocity, the specific impulse, and performance calculations. Aspects of propellant development considered include nonperformance requirements for solid propellants, the approach to development, propellant mechanical properties, and future trends.

  14. Advanced instrumental methods for analyzing organics in solid waste: The use of gas chromatography/matrix isolation infrared spectroscopy (GC/MIIR) and supercritical fluid chromatography (SFC) for waste characterization

    Raphaelian, L.A.; Boparai, A.S.; Schneider, J.F.


    Objectives of this research project were: (1) to enhance the capabilities of analyzing the complex mixtures found in coal wastes by using gas chromatography/matrix isolation infrared spectroscopy (GC/MIIR); (2) to separate, by supercritical fluid chromatography (SFC), the complex mixtures found in coal wastes into a few, less-complex mixtures so that analysis by gas chromatography (GC/MS) and GC/MIIR would be simplified. Preliminary results are presented for the mass spectra and infrared spectra of xylene isomers, gas chromatogram of 12 C/sub 2/-Napthalenes, averaged IR spectrum and a comparison of matrix isolation with light-pipe infrared spectra. A SFC chromatogram of polynuclear aromatic hydrocarbons is also presented. 2 refs., 5 figs.

  15. Bartonella entry mechanisms into mammalian host cells.

    Eicher, Simone C; Dehio, Christoph


    The Gram-negative genus Bartonella comprises arthropod-borne pathogens that typically infect mammals in a host-specific manner. Bartonella bacilliformis and Bartonella quintana are human-specific pathogens, while several zoonotic bartonellae specific for diverse animal hosts infect humans as an incidental host. Clinical manifestations of Bartonella infections range from mild symptoms to life-threatening disease. Following transmission by blood-sucking arthropods or traumatic contact with infected animals, bartonellae display sequential tropisms towards endothelial and possibly other nucleated cells and erythrocytes, the latter in a host-specific manner. Attachment to the extracellular matrix (ECM) and to nucleated cells is mediated by surface-exposed bacterial adhesins, in particular trimeric autotransporter adhesins (TAAs). The subsequent engulfment of the pathogen into a vacuolar structure follows a unique series of events whereby the pathogen avoids the endolysosomal compartments. For Bartonella henselae and assumingly most other species, the infection process is aided at different steps by Bartonella effector proteins (Beps). They are injected into host cells through the type IV secretion system (T4SS) VirB/D4 and subvert host cellular functions to favour pathogen uptake. Bacterial binding to erythrocytes is mediated by Trw, another T4SS, in a strictly host-specific manner, followed by pathogen-forced uptake involving the IalB invasin and subsequent replication and persistence within a membrane-bound intra-erythrocytic compartment.

  16. Dynamics of solid state coherent light sources

    Pollnau, M.; Di Bartolo, B.; Forte, O.


    This book chapter aims at reviewing in brief the fundamentals of rare-earth-ion spectroscopy in dielectric solids, with special emphasis on energy-transfer upconversion between neighboring active ions in a solid-state host lattice. The energy-level scheme of the 4f sub-shell of rare-earth ions is ex

  17. Solid lubricants

    Sliney, Harold E.


    The state of knowledge of solid lubricants is reviewed. The results of research on solid lubricants from the 1940's to the present are presented from a historical perspective. Emphasis is placed largely, but not exclusively, on work performed at NASA Lewis Research Center with a natural focus on aerospace applications. However, because of the generic nature of the research, the information presented in this review is applicable to most areas where solid lubricant technology is useful.

  18. Dye Photodestruction in a Solid-State Dye Laser with a Polymeric Gain Medium

    Popov, Sergei


    The process of dye photodestruction in a solid-state dye laser is studied, and implemented is a polymeric gain medium doped with a strongly concentrated dye. The behavior of the conversion efficiency in the polymeric gain medium pumped with different laser-pulse repetition rates and the process of dye photobleaching are analyzed. The contribution of the heating of the host material into the dye molecules deactivation is discussed. The negative effect of high dye concentration on the dye stability under a high pump repetition rate is reported and analyzed for the first time to my knowledge. A comparison of the present results with recently published data demonstrates the major role of photodestruction, rather than direct thermodestruction, in the dye stability of the solid-state gain medium. The role of additives with low molecular weights in the polymeric matrix, for increasing the stability of the gain material, is discussed.

  19. Solid Matter

    Angelo, Joseph A


    Supported by a generous quantity of full-color illustrations and interesting sidebars, Solid Matter introduces the basic characteristics and properties of solid matter. It briefly describes the cosmic connection of the elements, leading readers through several key events in human pre-history that resulted in more advanced uses of matter in the solid state. Chapters include:. -Solid Matter: An Initial Perspective. -Physical Behavior of Matter. -The Gravity of Matter. -Fundamentals of Materials Science. -Rocks and Minerals. -Metals. -Building Materials. -Carbon Earth's Most Versatile Element. -S

  20. Liquid-liquid extraction followed by solid-phase extraction for the determination of lipophilic pesticides in beeswax by gas chromatography-electron-capture detection and matrix-matched calibration.

    Jiménez, J J; Bernal, J L; del Nozal, Ma J; Alonso, C


    Analytical methods for the simultaneous analysis of lindane, chlorpyriphos, z-chlorfenvinphos, endosulfan A and B, 4,4'-DDE, 4,4'-TDE, acrinathrine, bromopropylate, tetradifon, coumaphos and fluvalinate in pure beeswax samples are studied. For the analysis of bleached beeswaxes, a liquid-liquid extraction with acetonitrile followed by a clean-up on polymeric cartridges is the best option in terms of recovery and precision. However, some interferences that hinder the identification and quantification of important varroacides are found when non-bleached beeswaxes are analyzed. The analysis of all compounds in the latter samples require a clean-up by coupling an ODS cartridge before the polymeric cartridge. Considerations about the influence of the matrix in the quantitative analysis by a classical external standard calibration are also made and the use of a matrix-matched calibration is advised. Recoveries resulted to be about 100% with coefficients of variation between 10% and 20% (n = 5) for concentrations of 0.5 and 5 mg/kg.

  1. Numerical matrix method for quantum periodic potentials

    Le Vot, Felipe; Meléndez, Juan J.; Yuste, Santos B.


    A numerical matrix methodology is applied to quantum problems with periodic potentials. The procedure consists essentially in replacing the true potential by an alternative one, restricted by an infinite square well, and in expressing the wave functions as finite superpositions of eigenfunctions of the infinite well. A matrix eigenvalue equation then yields the energy levels of the periodic potential within an acceptable accuracy. The methodology has been successfully used to deal with problems based on the well-known Kronig-Penney (KP) model. Besides the original model, these problems are a dimerized KP solid, a KP solid containing a surface, and a KP solid under an external field. A short list of additional problems that can be solved with this procedure is presented.

  2. Chemically modified tetracyclines: The novel host modulating agents

    Devulapalli Narasimha Swamy


    Full Text Available Periodontal pathogens and destructive host responses are involved in the initiation and progression of periodontitis. The emergence of host response modulation as a treatment concept has resulted from our improved understanding of the pathogenesis of periodontal disease. A variety of drugs have been evaluated as host modulation agents (HMA, including Non Steroidal Anti Inflammatory Drugs (NSAIDS, bisphosphonates, tetracyclines, enamel matrix proteins and bone morphogenetic proteins. Chemically modified tetracyclines (CMTs are one such group of drugs which have been viewed as potential host modulating agents by their anticollagenolytic property. The CMTs are designed to be more potent inhibitors of pro inflammatory mediators and can increase the levels of anti inflammatory mediators.

  3. Thermal conductivity of microPCMs-filled epoxy matrix composites

    Su, J.F.; Wang, X.Y; Huang, Z.; Zhao, Y.H.; Yuan, X.Y.


    Microencapsulated phase change materials (microPCMs) have been widely applied in solid matrix as thermal-storage or temperature-controlling functional composites. The thermal conductivity of these microPCMs/matrix composites is an important property need to be considered. In this study, a series of

  4. Stability evaluation of CNBr-Sepharose 4 B for using as solid matrix in immunoradiometric assay antibodies coupling; Avaliacao da estabilidade da CNBr-sepharose 4B para emprego como matriz solida no acoplamento de anticorpos especificos de ensaios imunorradiometricos

    Haber, Esther Piltcher; Silva, Sandra Rosa da; Borghi, Vania Caira [Instituto de Pesquisas Energeticas e Nucleares (IPEN), Sao Paulo, SP (Brazil); Wajchenberg, Bernardo Leo [Sao Paulo Univ., SP (Brazil). Faculdade de Medicina


    The present work verifies the stability of a CNBr-Sepharose 4 B product (Pharmacia) stored at our laboratory one year after its expire date in view of its application as solid phase antibodies in the development of an immunoradiometric assay for measurement of serum human proinsulin. From rabbit IgG antiserum previously purified and concentrated by ultrafiltration (Publication IPEN 294, 1990) the antibodies were isolated by affinity chromatography. Sheep antiserum anti-rabbit IgG were coupled to cyanogen bromide activated Sepharose 4 B and the rabbit IgG which were bound to the immunosorbent could be obtained by elution with stepwise pH gradient from pH 7.0 to pH 2.5. The complying efficiency of the sheep antiserum to this solid phase material was 97%. The elution profile obtained shows identify of the sample related to the antiserum anti-rabbit IgG by affinity chromatography. These results suggest that this CNBr-Sepharose 4 B lot can be used satisfactorily to attach antibodies for use in the two-site immunoradiometric assay. (author). 7 refs., 1 fig.

  5. High ionic conductivity P(VDF-TrFE)/PEO blended polymer electrolytes for solid electrochromic devices.

    Nguyen, Chien A; Xiong, Shanxin; Ma, Jan; Lu, Xuehong; Lee, Pooi See


    Solid polymer electrolytes with excellent ionic conductivity (above 10(-4) S cm(-1)), which result in high optical modulation for solid electrochromic (EC) devices are presented. The combination of a polar host matrix poly(vinylidene fluoride-trifluoroethylene) P(VDF-TrFE) and a solid plasticized of a low molecular weight poly(ethylene oxide) (PEO) (M(w)≤ 20,000) blended polymer electrolyte serves to enhance both the dissolution of lithium salt and the ionic transport. Calorimetric measurement shows a reduced crystallization due to a better intermixing of the polymers with small molecular weight PEO. Vibrational spectroscopy identifies the presence of free ions and ion pairs in the electrolytes with PEO of M(w)≤ 8000. The ionic dissolution is improved using PEO as a plasticizer when compared to liquid propylene carbonate, evidently shown in the transference number analysis. Ionic transport follows the Arrhenius equation with a low activation energy (0.16-0.2 eV), leading to high ionic conductivities. Solid electrochromic devices fabricated with the blended P(VDF-TrFE)/PEO electrolytes and polyaniline show good spectroelectrochemical performance in the visible (300-800 nm) and near-infrared (0.9-2.4 μm) regions with a modulation up to 60% and fast switching speed of below 20 seconds. The successful introduction of the solid polymer electrolytes with its best harnessed qualities helps to expedite the application of various electrochemical devices. This journal is © the Owner Societies 2011

  6. Amino Acids in the Asteroidal Water-Bearing Salt Crystals Hosted in the Zag Meteorite

    Chan, Q. H. S.; Zolensky, M. E.; Burton, A. S.; Locke, D. R.


    Solid evidence of liquid water in primitive meteorites is given by the ordinary chondrites H5 Monahans (1998) and H3-6 Zag. Aqueous fluid inclusion-bearing halite (NaCl) crystals were shown to be common in Zag. These striking blue/purple crystals (Figure 1), which gained the coloration from electron-trapping in the Cl-vacancies through exposure to ionizing radiation, were determined to be over 4.0-4.7 billion years old by I-Xe dating. The halite grains are present as discrete grains within an H-chondrite matrix with no evidence for aqueous alteration that indicates a xenogenic source, possibly ancient cryovolcanism. They were proposed to be formed from the cryovolcanic plumes on icy C-type asteroids (possibly Ceres), and were transferred and incorporated into the H chondrite parent asteroid following the eruption event(s). A unique aspect of these halites is that they contain abundant solid inclusions hosted within the halites alongside the water inclusions. The solid inclusions were suggested to be entrained within the fluid erupted from the cryovolcanic event(s), and were shown to be comprised of abundant organics. Spectrofluorometric study and Raman imaging of the halites have identified macromolecular carbon and aliphatic carbon compounds. In order to investigate the type of organics present in Zag and in particular within the fluid-bearing halites, we studied for the first time the amino acid contents of a selected mineral (halite) phase in a meteorite sample.

  7. Enhancement of ionic conductivity of composite membranes for all-solid-state lithium rechargeable batteries incorporating tetragonal Li7La3Zr2O12 into a polyethylene oxide matrix

    Choi, Jeong-Hee; Lee, Chul-Ho; Yu, Ji-Hyun; Doh, Chil-Hoon; Lee, Sang-Min


    The lithium ion conductivities of as-prepared composite membranes consisting of a polyethylene oxide (PEO) matrix with various contents of tetragonal Li7La3Zr2O12 (LLZO) were evaluated, and the optimum composition (52.5% LLZO) was determined by performing AC impedance measurements. The ionic conductivities of the composite membranes pass through a maximum as the LLZO content varies. Therefore, the hybridization of the organic and inorganic components of these membranes results in synergetic effects on their lithium ionic conductivity. In addition, tests of Li/composite membrane/LiNi0.6Co0.2Mn0.2O2 half-cells found that their charge/discharge properties are better than those of a PEO-only membrane and a membrane containing 52.5% Al2O3 instead of LLZO.

  8. Baculovirus Host-Range

    Suzanne M. Thiem; Xiao-Wen Cheng


    Baculoviruses are used as microbial insecticides, protein expression vectors, epitope display platforms, and most recently as vectors for gene therapy. Understanding the mechanisms that control baculovirus host-range and tissue tropisms are important for assessing their safety and for improving their properties for these biotechnology applications. In the past two decades some progress has been made and several baculovirus genes that influence host-range have been identified. Despite this progress, our understanding of the underlying mechanisms that restrict baculovirus host-range is still limited. Here we review what is currently known about baculovirus genes that influence virus host-range.

  9. New Hosts of The Lassa Virus.

    Olayemi, Ayodeji; Cadar, Daniel; Magassouba, N'Faly; Obadare, Adeoba; Kourouma, Fode; Oyeyiola, Akinlabi; Fasogbon, Samuel; Igbokwe, Joseph; Rieger, Toni; Bockholt, Sabrina; Jérôme, Hanna; Schmidt-Chanasit, Jonas; Garigliany, Mutien; Lorenzen, Stephan; Igbahenah, Felix; Fichet, Jean-Nicolas; Ortsega, Daniel; Omilabu, Sunday; Günther, Stephan; Fichet-Calvet, Elisabeth


    Lassa virus (LASV) causes a deadly haemorrhagic fever in humans, killing several thousand people in West Africa annually. For 40 years, the Natal multimammate rat, Mastomys natalensis, has been assumed to be the sole host of LASV. We found evidence that LASV is also hosted by other rodent species: the African wood mouse Hylomyscus pamfi in Nigeria, and the Guinea multimammate mouse Mastomys erythroleucus in both Nigeria and Guinea. Virus strains from these animals were isolated in the BSL-4 laboratory and fully sequenced. Phylogenetic analyses of viral genes coding for glycoprotein, nucleoprotein, polymerase and matrix protein show that Lassa strains detected in M. erythroleucus belong to lineages III and IV. The strain from H. pamfi clusters close to lineage I (for S gene) and between II &III (for L gene). Discovery of new rodent hosts has implications for LASV evolution and its spread into new areas within West Africa.

  10. Optical properties of matrix confined species

    Lezhnina, M. M.; Kynast, U. H.


    A majority of optically functional materials can be perceived as a liaison between ionic or molecular guests and a more or less rigid host. The guests exhibit an optical function, whereas the host provides suitable space, both of them synergistically complementing each other. The embracement of guests and hosts is often very intimate, as e.g. in typical phosphors, where luminescent ions even become part of the host. While the host-guest terminology usually is not applied to such marriages, the term becomes appropriate, if the host grants some degrees of spatial freedom, yet giving order and structure to its guests. Zeolites, clays and inverse opals are porous materials naturally providing hospitable cavities, channels or other compartments, and at the same time the guests are often demanded to occupy preassigned positions within these, or to structurally adapt to the interior host topology. Whereas zeolites and clays are merely patient providers of guest space, inverse opals, can actively turn the light on and off. The present article summarises and highlights recent experimental evidence, ongoing research and some envisaged merits resulting from the interaction of matrix confined luminescent ions, complexes and molecules with a focus on the optical properties of rare earth based materials.

  11. The Matrix Cookbook

    Petersen, Kaare Brandt; Pedersen, Michael Syskind

    Matrix identities, relations and approximations. A desktop reference for quick overview of mathematics of matrices.......Matrix identities, relations and approximations. A desktop reference for quick overview of mathematics of matrices....

  12. Solid consistency

    Bordin, Lorenzo; Creminelli, Paolo; Mirbabayi, Mehrdad; Noreña, Jorge


    We argue that isotropic scalar fluctuations in solid inflation are adiabatic in the super-horizon limit. During the solid phase this adiabatic mode has peculiar features: constant energy-density slices and comoving slices do not coincide, and their curvatures, parameterized respectively by ζ and Script R, both evolve in time. The existence of this adiabatic mode implies that Maldacena's squeezed limit consistency relation holds after angular average over the long mode. The correlation functions of a long-wavelength spherical scalar mode with several short scalar or tensor modes is fixed by the scaling behavior of the correlators of short modes, independently of the solid inflation action or dynamics of reheating.

  13. Structure and assembly of a paramyxovirus matrix protein.

    Battisti, Anthony J; Meng, Geng; Winkler, Dennis C; McGinnes, Lori W; Plevka, Pavel; Steven, Alasdair C; Morrison, Trudy G; Rossmann, Michael G


    Many pleomorphic, lipid-enveloped viruses encode matrix proteins that direct their assembly and budding, but the mechanism of this process is unclear. We have combined X-ray crystallography and cryoelectron tomography to show that the matrix protein of Newcastle disease virus, a paramyxovirus and relative of measles virus, forms dimers that assemble into pseudotetrameric arrays that generate the membrane curvature necessary for virus budding. We show that the glycoproteins are anchored in the gaps between the matrix proteins and that the helical nucleocapsids are associated in register with the matrix arrays. About 90% of virions lack matrix arrays, suggesting that, in agreement with previous biological observations, the matrix protein needs to dissociate from the viral membrane during maturation, as is required for fusion and release of the nucleocapsid into the host's cytoplasm. Structure and sequence conservation imply that other paramyxovirus matrix proteins function similarly.

  14. Matrix with Prescribed Eigenvectors

    Ahmad, Faiz


    It is a routine matter for undergraduates to find eigenvalues and eigenvectors of a given matrix. But the converse problem of finding a matrix with prescribed eigenvalues and eigenvectors is rarely discussed in elementary texts on linear algebra. This problem is related to the "spectral" decomposition of a matrix and has important technical…

  15. Acute graft versus host disease

    Vogelsang Georgia B


    Full Text Available Abstract Acute graft-versus-host disease (GVHD occurs after allogeneic hematopoietic stem cell transplant and is a reaction of donor immune cells against host tissues. Activated donor T cells damage host epithelial cells after an inflammatory cascade that begins with the preparative regimen. About 35%–50% of hematopoietic stem cell transplant (HSCT recipients will develop acute GVHD. The exact risk is dependent on the stem cell source, age of the patient, conditioning, and GVHD prophylaxis used. Given the number of transplants performed, we can expect about 5500 patients/year to develop acute GVHD. Patients can have involvement of three organs: skin (rash/dermatitis, liver (hepatitis/jaundice, and gastrointestinal tract (abdominal pain/diarrhea. One or more organs may be involved. GVHD is a clinical diagnosis that may be supported with appropriate biopsies. The reason to pursue a tissue biopsy is to help differentiate from other diagnoses which may mimic GVHD, such as viral infection (hepatitis, colitis or drug reaction (causing skin rash. Acute GVHD is staged and graded (grade 0-IV by the number and extent of organ involvement. Patients with grade III/IV acute GVHD tend to have a poor outcome. Generally the patient is treated by optimizing their immunosuppression and adding methylprednisolone. About 50% of patients will have a solid response to methylprednisolone. If patients progress after 3 days or are not improved after 7 days, they will get salvage (second-line immunosuppressive therapy for which there is currently no standard-of-care. Well-organized clinical trials are imperative to better define second-line therapies for this disease. Additional management issues are attention to wound infections in skin GVHD and fluid/nutrition management in gastrointestinal GVHD. About 50% of patients with acute GVHD will eventually have manifestations of chronic GVHD.

  16. SolidWorks 2011 Assemblies Bible

    Lombard, Matt


    A fan of the SolidWorks Bible, but want more detail on assemblies? Here you go. SolidWorks fans have long sought more detail on SolidWorks topics, and now you have it. We took our popular SolidWorks Bible, divided it into two books (SolidWorks 2011 Assemblies Bible and SolidWorks 2011 Parts Bible) and packed each new book with a host of items from your wish lists, such as more extensive coverage of the basics, additional tutorials, and expanded coverage of topics largely ignored by other books. This SolidWorks 2011 Assemblies Bible shows you how to organize parts data to create assemblies or s

  17. Deposition of matrix-free fullerene films with improved morphology by matrix-assisted pulsed laser evaporation (MAPLE)

    Canulescu, Stela; Schou, Jørgen; Fæster, Søren;


    Thin films of C60 were deposited by matrix-assisted pulsed laser evaporation (MAPLE) from a frozen target of anisole with 0.67 wt% C60. Above a fluence of 1.5 J/cm2 the C60 films are strongly non-uniform and are resulting from transfer of matrix-droplets containing fullerenes. At low fluence...... the fullerene molecules in the films are intact, the surface morphology is substantially improved and there are no measurable traces of the matrix molecules in the film. This may indicate a regime of dominant evaporation at low fluence which merges into the MAPLE regime of liquid ejection of the host matrix...

  18. Matrix-compatible sorbent coatings based on structurally-tuned polymeric ionic liquids for the determination of acrylamide in brewed coffee and coffee powder using solid-phase microextraction.

    Cagliero, Cecilia; Nan, He; Bicchi, Carlo; Anderson, Jared L


    Nine crosslinked polymeric ionic liquid (PIL)-based SPME sorbent coatings were designed and screened in this study for the trace level determination of acrylamide in brewed coffee and coffee powder using gas chromatography-mass spectrometry (GC-MS). The structure of the ionic liquid (IL) monomer was tailored by introducing different functional groups to the cation and the nature of the IL crosslinker was designed by altering both the structure of the cation as well as counteranions. The extraction efficiency of the new PIL coatings towards acrylamide was investigated and compared to a previously reported PIL sorbent coating. All PIL fibers exhibited excellent analytical precision and linearity. The PIL fiber coating consisting of 50% 1,12-di(3-vinylbenzylbenzimidazolium)dodecane dibis[(trifluoromethyl)sulfonyl]imide as IL crosslinker in 1-vinyl-3-(10-hydroxydecyl)imidazolium bis[(trifluoromethyl)sulfonyl]imide IL monomer resulted in a limit of quantitation of 0.5μgL(-1) with in-solution SPME sampling. The hydroxyl moiety appended to the IL cation was observed to significantly increase the sensitivity of the PIL coating toward acrylamide. The quantitation of acrylamide in brewed coffee and coffee powder was performed using the different PIL-based fibers by the method of standard addition after a quenching reaction using ninhydrin to inhibit the formation of interfering acrylamide in the GC inlet, mainly by asparagine thermal degradation. Excellent repeatability with relative standard deviations below 10% were obtained on the real coffee samples and the structure of the coatings appeared intact by scanning electron microscopy after coffee sampling proving the matrix-compatibility of the PIL sorbent coatings.

  19. Acoustic superfocusing by solid phononic crystals

    Zhou, Xiaoming; Assouar, M. Badreddine; Oudich, Mourad


    We propose a solid phononic crystal lens capable of acoustic superfocusing beyond the diffraction limit. The unit cell of the crystal is formed by four rigid cylinders in a hosting material with a cavity arranged in the center. Theoretical studies reveal that the solid lens produces both negative refraction to focus propagating waves and surface states to amplify evanescent waves. Numerical analyses of the superfocusing effect of the considered solid phononic lens are presented with a separated source excitation to the lens. In this case, acoustic superfocusing beyond the diffraction limit is evidenced. Compared to the fluid phononic lenses, the solid lens is more suitable for ultrasonic imaging applications.

  20. Inflammatory Alterations of the Extracellular Matrix in the Tumor Microenvironment

    Iijima, Junko [Department of Molecular Biosciences, Faculty of Life Sciences, Kyoto Sangyo University, Motoyama, Kamigamo, Kita-Ku, Kyoto 603-8555 (Japan); Konno, Kenjiro [Department of Animal Medical Sciences, Faculty of Life Sciences, Kyoto Sangyo University, Motoyama, Kamigamo, Kita-Ku, Kyoto 603-8555 (Japan); Itano, Naoki, E-mail: [Department of Molecular Biosciences, Faculty of Life Sciences, Kyoto Sangyo University, Motoyama, Kamigamo, Kita-Ku, Kyoto 603-8555 (Japan)


    Complex interactions between cancer cells and host stromal cells result in the formation of the “tumor microenvironment”, where inflammatory alterations involve the infiltration of tumor-associated fibroblasts and inflammatory leukocytes that contribute to the acquisition of malignant characteristics, such as increased cancer cell proliferation, invasiveness, metastasis, angiogenesis, and avoidance of adaptive immunity. The microenvironment of a solid tumor is comprised not only of cellular compartments, but also of bioactive substances, including cytokines, growth factors, and extracellular matrix (ECM). ECM can act as a scaffold for cell migration, a reservoir for cytokines and growth factors, and a signal through receptor binding. During inflammation, ECM components and their degraded fragments act directly and indirectly as inflammatory stimuli in certain cases and regulate the functions of inflammatory and immune cells. One such ECM component, hyaluronan, has recently been implicated to modulate innate immune cell function through pattern recognition toll-like receptors and accelerate the recruitment and activation of tumor-associated macrophages in inflamed cancers. Here, we will summarize the molecular mechanism linking inflammation with ECM remodeling in the tumor microenvironment, with a particular emphasis on the role of hyaluronan in controlling the inflammatory response.

  1. The participation ratios of cement matrix and latex network in latex cement co-matrix strength

    Ahmed M. Diab


    Full Text Available This investigation aims to determine the participation ratio of cement matrix and latex network in latex cement co-matrix strength. The first stage of this study was carried out to investigate the effect of styrene butadiene rubber (SBR on cement matrix participation ratio by measuring degree of hydration and compressive strength. The second stage in this study shows an attempt to evaluate the latex participation ratio in mortar and concrete strength with different latex chemical bases. Effect of latex particle size on latex network strength was studied. The test results indicated that the latex participation ratio in co-matrix strength is influenced by type of cement matrix, type of curing, latex type, latex solid/water ratio, strength type and age. For modified concrete, when the SBR solid/water ratio increases the latex participation ratio in flexural and pull out bond strength increases. The latex participation ratio in co-matrix strength decreases as latex particle size increases.

  2. Matrix Solid-phase Dispersion and Gas Chromatographic Analysis and Matrix Effect in Determination of 6 Fungicides Residues in Fruits and Vegetables%果蔬中6种杀真菌剂残留的固相分散气相色谱检测及基质效应



    A rapid method based on matrix solid—phase dispersion was developed for the determination of pen-tachloronitrobenzene (PCNB), pentachloraniline (PCA), methyl-pentachlorophenyl sulfide (MPCS), procymidone(PRO), captan(CAP) and Iprodione(IPR) in fruits and vegetables. After the optimisation of different parameters such as the type of adsorbent, the extraction solvent, and the extraction assistance by sonication. The analysis of samples was accomplished using gas chromatography with electron-capture detector(GC-ECD). Spiked blank samples were used as standards to counteract the matrix effect observed in the chromatographie determination. The results showed the recoveries of the method were in the range 78.4%~109.7%, and with relative standard deviations lower than 10%. The limits of detections ranged from 0.1-0.4 μg/kg. The proposed methods were applied to the analysis of these compounds in fruits and vegetables samples.%采用基质固相分散样品前处理技术,气相色谱-电子捕获检测器测定果蔬中残留的常用杀真菌剂--五氯硝基苯(PCNB)、五氯苯胺(PCA)、甲基五氯苯基硫醚(MPCS)、腐霉利(PRO)、克茵丹(CAP)和异茵脲(IPR).对影响提取效果的参数,如吸附剂类型、提取溶剂、超声波辅助提取等工艺条件进行优化.利用空白基质配制标准样品溶液来补偿和消除色谱分析中存在的基质效应,结果表明,该方法的回收率在78.4%~109.7%,相对标准偏差低于10%,检测限0.1~0.4 ug/kg.该方法可用于水果、蔬菜中杀真菌剂残留量的测定.

  3. Parallelism in matrix computations

    Gallopoulos, Efstratios; Sameh, Ahmed H


    This book is primarily intended as a research monograph that could also be used in graduate courses for the design of parallel algorithms in matrix computations. It assumes general but not extensive knowledge of numerical linear algebra, parallel architectures, and parallel programming paradigms. The book consists of four parts: (I) Basics; (II) Dense and Special Matrix Computations; (III) Sparse Matrix Computations; and (IV) Matrix functions and characteristics. Part I deals with parallel programming paradigms and fundamental kernels, including reordering schemes for sparse matrices. Part II is devoted to dense matrix computations such as parallel algorithms for solving linear systems, linear least squares, the symmetric algebraic eigenvalue problem, and the singular-value decomposition. It also deals with the development of parallel algorithms for special linear systems such as banded ,Vandermonde ,Toeplitz ,and block Toeplitz systems. Part III addresses sparse matrix computations: (a) the development of pa...

  4. 基质固相分散-气相色谱热能检测法测定电子烟烟油中的TSNAs%Determination of TSNAs in electronic cigarette liquids by GC-TEA with matrix solid phase dispersion

    张凤梅; 杨光宇; 刘志华; 朱瑞芝; 司晓喜; 刘春波; 申钦鹏; 何沛; 王昆淼


    利用基质固相分散-气相色谱热能检测法测定电子烟烟油中的烟草特有亚硝胺(TSNAs).电子烟烟油用碱性氧化铝分散处理,然后用带柱层析净化功能的索氏提取器净化.经净化后的样品用气相色谱热能进行检测分析.在选定条件下,NNK、NNN、NAB、NAT的4种烟草特有亚硝胺检出限分别为7.6、12.8、13.2、4.0 ng/mL,方法的回收率为89.6%~ 94.7%;对样品进行7次测定,日内相对标准偏差为3.2% ~4.0%;日间相对标准偏差为4.2% ~4.6%,结果令人满意.%A matrix solid phase dispersion and gas chromatography method are used to determine N-nitrosamines (TSNAs) in electronic cigarette liquids in combination with matrix solid phase dispersion.The electronic cigarette liquids samples are firstly dispersed with basic alumina and purified by basic alumina column chromatography combined with cable extraction.The purified samples are analyzed by gas chromatouraphy equipped with thermal energy analyser (TEA).The detection limits for four TSNAs (NNK、NNN、NAB、NAT) are 7.6,12.8,13.2,and 4.0 ng/mL,respectively.The developed method provides spiked recoveries of 89.6%-94.7% for TSNAs.The intra-day relative standard deviations are 3.2%-4.0% and the inter-day relative standard deviations are 4.2%-4.6%.This method is applied for the determination of TSNAs in electronic cigarette liquids with good results.

  5. Phosphine in various matrixes


    Matrix-bound phosphine was determined in the Jiaozhou Bay coastal sediment, in prawn-pond bottom soil, in the eutrophic lake Wulongtan, in the sewage sludge and in paddy soil as well. Results showed that matrix-bound phosphine levels in freshwater and coastal sediment, as well as in sewage sludge, are significantly higher than that in paddy soil. The correlation between matrix bound phosphine concentrations and organic phosphorus contents in sediment samples is discussed.

  6. Synthesis, spectroscopy, and electrochemistry of ionic hosts for organic electronics

    Shavaleev, Nail M.; Nazeeruddin, Mohammad K.


    We report on charge- and ion-transport ionic hosts made from an imidazolium-cation-modified aryl-1,2,4-triazole, phosphineoxide-carbazole, and phosphineoxide. The hosts are white solids that have short-wavelength absorption cut-off at 28,200 cm-1) and that exhibit oxidation at (-2.75) V against ferrocene with a wide redox gap of >3.9 V.

  7. Nanophosphor composite scintillators comprising a polymer matrix

    Muenchausen, Ross Edward; Mckigney, Edward Allen; Gilbertson, Robert David


    An improved nanophosphor composite comprises surface modified nanophosphor particles in a solid matrix. The nanophosphor particle surface is modified with an organic ligand, or by covalently bonding a polymeric or polymeric precursor material. The surface modified nanophosphor particle is essentially charge neutral, thereby preventing agglomeration of the nanophosphor particles during formation of the composite material. The improved nanophosphor composite may be used in any conventional scintillator application, including in a radiation detector.

  8. Association and host selectivity in multi-host pathogens.

    José M Malpica

    Full Text Available The distribution of multi-host pathogens over their host range conditions their population dynamics and structure. Also, host co-infection by different pathogens may have important consequences for the evolution of hosts and pathogens, and host-pathogen co-evolution. Hence it is of interest to know if the distribution of pathogens over their host range is random, or if there are associations between hosts and pathogens, or between pathogens sharing a host. To analyse these issues we propose indices for the observed patterns of host infection by pathogens, and for the observed patterns of co-infection, and tests to analyse if these patterns conform to randomness or reflect associations. Applying these tests to the prevalence of five plant viruses on 21 wild plant species evidenced host-virus associations: most hosts and viruses were selective for viruses and hosts, respectively. Interestingly, the more host-selective viruses were the more prevalent ones, suggesting that host specialisation is a successful strategy for multi-host pathogens. Analyses also showed that viruses tended to associate positively in co-infected hosts. The developed indices and tests provide the tools to analyse how strong and common are these associations among different groups of pathogens, which will help to understand and model the population biology of multi-host pathogens.

  9. Engineered glass seals for solid-oxide fuel cells

    Surdoval, Wayne; Lara-Curzio, Edgar; Stevenson, Jeffry; Muth, Joseph Thomas; Armstrong, Beth L.; Shyam, Amit; Trejo, Rosa M.; Wang, Yanli; Chou, Yeong Shyung; Shultz, Travis Ray


    A seal for a solid oxide fuel cell includes a glass matrix having glass percolation therethrough and having a glass transition temperature below C. A deformable second phase material is dispersed in the glass matrix. The second phase material can be a compliant material. The second phase material can be a crushable material. A solid oxide fuel cell, a precursor for forming a seal for a solid oxide fuel cell, and a method of making a seal for a solid oxide fuel cell are also disclosed.

  10. Engineered glass seals for solid-oxide fuel cells

    Surdoval, Wayne; Lara-Curzio, Edgar; Stevenson, Jeffry; Muth, Joseph Thomas; Armstrong, Beth L.; Shyam, Amit; Trejo, Rosa M.; Wang, Yanli; Chou, Yeong Shyung; Shultz, Travis Ray


    A seal for a solid oxide fuel cell includes a glass matrix having glass percolation therethrough and having a glass transition temperature below C. A deformable second phase material is dispersed in the glass matrix. The second phase material can be a compliant material. The second phase material can be a crushable material. A solid oxide fuel cell, a precursor for forming a seal for a solid oxide fuel cell, and a method of making a seal for a solid oxide fuel cell are also disclosed.

  11. Scandia doped tungsten matrix for impregnated cathode

    WANG Jinshu; WANG Yanchun; LIU Wei; LI Hongyi; ZHOU Meiling


    As a matrix for Sc-type impregnated cathode,scandia doped tungsten with a uniform ldistribution of SC2O3 was obtained by powder metallurgy combined with the liquid-solid doping method.The microstructure and composition of the powder and the anti-ion bombardment behavior of scandium in the matrix were studied by means of SEM,EDS,XRD,and in-situ AES methods.Tungsten powder covered with scandium oxide,an ideal scandium oxide-doped tungsten powder for the preparation of Sc-type impregnated cathode,was obtained using the liquid-solid doping method.Compared with the matrix prepared with the mechanically mixed powder of tungsten and scandium oxide,SC2O3-W matrix prepared with this kind of powder had smaller grain size and uniform distribution of scandium.Sc on the surface of Sc2O3 doped tungsten mauix had good high temperature stability and good anti-ion bombardment capability.

  12. Parasite host range and the evolution of host resistance

    Gorter, F.A.; Hall, A.R.; A., Buckling; P.D., Scanlan


    Parasite host range plays a pivotal role in the evolution and ecology of hosts
    and the emergence of infectious disease. Although the factors that promote
    host range and the epidemiological consequences of variation in host range
    are relatively well characterized, the effect of parasite

  13. Patience of matrix games

    Hansen, Kristoffer Arnsfelt; Ibsen-Jensen, Rasmus; Podolskii, Vladimir V.;


    For matrix games we study how small nonzero probability must be used in optimal strategies. We show that for image win–lose–draw games (i.e. image matrix games) nonzero probabilities smaller than image are never needed. We also construct an explicit image win–lose game such that the unique optimal...

  14. Patience of matrix games

    Hansen, Kristoffer Arnsfelt; Ibsen-Jensen, Rasmus; Podolskii, Vladimir V.


    For matrix games we study how small nonzero probability must be used in optimal strategies. We show that for image win–lose–draw games (i.e. image matrix games) nonzero probabilities smaller than image are never needed. We also construct an explicit image win–lose game such that the unique optimal...

  15. Transfer function matrix

    Seraji, H.


    Given a multivariable system, it is proved that the numerator matrix N(s) of the transfer function evaluated at any system pole either has unity rank or is a null matrix. It is also shown that N(s) evaluated at any transmission zero of the system has rank deficiency. Examples are given for illustration.

  16. Lensed Quasar Hosts

    Peng, C Y; Rix, H W; Keeton, C R; Falco, E E; Kochanek, C S; Lehár, J; McLeod, B A; Peng, Chien Y.; Impey, Chris D.; Rix, Hans-Walter; Keeton, Charles R.; Falco, Emilio E.; Kochanek, Chris S.; Lehar, Joseph; Leod, Brian A. Mc


    Gravitational lensing assists in the detection of quasar hosts by amplifying and distorting the host light away from the unresolved quasar core images. We present the results of HST observations of 30 quasar hosts at redshifts 1 1.7 is a factor of 3--6 higher than the local value. But, depending on the stellar content the ratio may decline at z>4 (if E/S0-like), flatten off to 6--10 times the local value (if Sbc-like), or continue to rise (if Im-like). We infer that galaxy bulge masses must have grown by a factor of 3--6 over the redshift range 3>z>1, and then changed little since z~1. This suggests that the peak epoch of galaxy formation for massive galaxies is above z~1. We also estimate the duty cycle of luminous AGNs at z>1 to be ~1%, or 10^7 yrs, with sizable scatter.

  17. A crystal chemistry approach for high-power ytterbium doped solid-state lasers: diffusion-bonded crystals and new crystalline hosts; Relations structures-proprietes dans les lasers solides de puissance a l'ytterbium: elaboration et caracterisation de nouveaux materiaux et de cristaux composites soudes par diffusion

    Gaume, R


    This work deals with ytterbium based crystals for high-power laser applications. In particular, we focus our interest in reducing crystal heating and its consequences during laser operation following two different ways. First, we review the specific properties of ytterbium doped solid-state lasers in order to define a figure-of-merit which gives the evaluation of laser performances, thermo-mechanical and thermo-optical properties. Bearing in mind this analysis, we propose a set of theoretical tools, based on the crystallographic structure of the crystal and its chemical composition, to predict thermo-mechanical and optical potentials. This approach, used for the seek of new Yb{sup 3+}-doped materials for high-power laser applications, shows that simple oxides containing rare-earths are favorable. Therefore, the spectroscopic properties of six new materials Yb{sup 3+}:GdVO{sub 4}, Yb{sup 3+}:GdAlO{sub 3}, Yb{sup 3+}:Gd{sub 2}O{sub 3}, Yb{sup 3+}:Sc{sub 2}SiO{sub 5}, Yb{sup 3+}:CaSc{sub 2}O{sub 4} and Yb{sup 3+}:SrSc{sub 2}O{sub 4} are described. The second aspect developed in this work deals with thermal properties enhancement of already well characterized laser materials. Two different ways are explored: a) elaboration by diffusion bonding of end-caps lasers with undoped crystals (composite crystals). Thus, different composites were obtained and a fairly lowering of thermal lensing effect was observed during laser operation. b) strengthening of crystalline structures by ionic substitution of one of its constituents. We demonstrate how crystal growth ability can be improved by a cationic substitution in the case of Yb{sup 3+}:BOYS, a largely-tunable laser material which is of great interest for femtosecond pulses generation. (author)

  18. Review on Fabrication Methods of in situ Metal Matrix Composites


    This paper deals with a series of novel processing techniques based on the in situ production of metal matrix composites (MMCs). In situ techniques involve a chemical reaction resulting in the formation of a very fine and thermodynamically stable reinforcing ceramic phase within a metal matrix. As a result, this provides thermodynamic compatibility at the matrix-reinforcement interface. The reinforcement surfaces are also likely to be free of contamination and, therefore, a stronger matrix-dispersion bond can be achieved. Some of these technologies including DIMOXTM, XD, PRIMEXTM, reactive gas infiltration, high-temperature self-propagating synthesis (SHS), and liquid-solid, or solid-gas-liquid reactions as well as plasma in situ MMCs are expressed in this paper.

  19. Improved Matrix Uncertainty Selector

    Rosenbaum, Mathieu


    We consider the regression model with observation error in the design: y=X\\theta* + e, Z=X+N. Here the random vector y in R^n and the random n*p matrix Z are observed, the n*p matrix X is unknown, N is an n*p random noise matrix, e in R^n is a random noise vector, and \\theta* is a vector of unknown parameters to be estimated. We consider the setting where the dimension p can be much larger than the sample size n and \\theta* is sparse. Because of the presence of the noise matrix N, the commonly used Lasso and Dantzig selector are unstable. An alternative procedure called the Matrix Uncertainty (MU) selector has been proposed in Rosenbaum and Tsybakov (2010) in order to account for the noise. The properties of the MU selector have been studied in Rosenbaum and Tsybakov (2010) for sparse \\theta* under the assumption that the noise matrix N is deterministic and its values are small. In this paper, we propose a modification of the MU selector when N is a random matrix with zero-mean entries having the variances th...

  20. Avian host defense peptides

    Cuperus, Tryntsje; Coorens, M.; van Dijk, A.; Haagsman, H.P.


    Host defense peptides (HDPs) are important effector molecules of the innate immune system of vertebrates. These antimicrobial peptides are also present in invertebrates, plants and fungi. HDPs display broad-spectrum antimicrobial activities and fulfill an important role in the first line of defense

  1. SARS Pathogenesis: Host Factors

    A. de Lang (Anna)


    textabstractWhile it is hypothesized that Sever Acute Respiratory Syndrome (SARS) in humans is caused by a disproportional immune response illustrated by inappropriate induction of inflammatory cytokines, the exact nature of the host response to SARS coronavirus (CoV) infection causing severe

  2. Elementary matrix theory

    Eves, Howard


    The usefulness of matrix theory as a tool in disciplines ranging from quantum mechanics to psychometrics is widely recognized, and courses in matrix theory are increasingly a standard part of the undergraduate curriculum.This outstanding text offers an unusual introduction to matrix theory at the undergraduate level. Unlike most texts dealing with the topic, which tend to remain on an abstract level, Dr. Eves' book employs a concrete elementary approach, avoiding abstraction until the final chapter. This practical method renders the text especially accessible to students of physics, engineeri

  3. Rheocasting Al matrix composites

    Girot, F.A.; Albingre, L.; Quenisset, J.M.; Naslain, R.


    A development status account is given for the rheocasting method of Al-alloy matrix/SiC-whisker composites, which involves the incorporation and homogeneous distribution of 8-15 vol pct of whiskers through the stirring of the semisolid matrix melt while retaining sufficient fluidity for casting. Both 1-, 3-, and 6-mm fibers of Nicalon SiC and and SiC whisker reinforcements have been experimentally investigated, with attention to the characterization of the resulting microstructures and the effects of fiber-matrix interactions. A thin silica layer is found at the whisker surface. 7 references.

  4. Mueller matrix differential decomposition.

    Ortega-Quijano, Noé; Arce-Diego, José Luis


    We present a Mueller matrix decomposition based on the differential formulation of the Mueller calculus. The differential Mueller matrix is obtained from the macroscopic matrix through an eigenanalysis. It is subsequently resolved into the complete set of 16 differential matrices that correspond to the basic types of optical behavior for depolarizing anisotropic media. The method is successfully applied to the polarimetric analysis of several samples. The differential parameters enable one to perform an exhaustive characterization of anisotropy and depolarization. This decomposition is particularly appropriate for studying media in which several polarization effects take place simultaneously. © 2011 Optical Society of America

  5. Host Phylogeny Determines Viral Persistence and Replication in Novel Hosts

    Longdon, Ben; Hadfield, Jarrod D.; Webster, Claire L.


    Pathogens switching to new hosts can result in the emergence of new infectious diseases, and determining which species are likely to be sources of such host shifts is essential to understanding disease threats to both humans and wildlife. However, the factors that determine whether a pathogen can infect a novel host are poorly understood. We have examined the ability of three host-specific RNA-viruses (Drosophila sigma viruses from the family Rhabdoviridae) to persist and replicate in 51 different species of Drosophilidae. Using a novel analytical approach we found that the host phylogeny could explain most of the variation in viral replication and persistence between different host species. This effect is partly driven by viruses reaching a higher titre in those novel hosts most closely related to the original host. However, there is also a strong effect of host phylogeny that is independent of the distance from the original host, with viral titres being similar in groups of related hosts. Most of this effect could be explained by variation in general susceptibility to all three sigma viruses, as there is a strong phylogenetic correlation in the titres of the three viruses. These results suggest that the source of new emerging diseases may often be predictable from the host phylogeny, but that the effect may be more complex than simply causing most host shifts to occur between closely related hosts. PMID:21966271

  6. An Osteoconductive Antibiotic Bone Eluting Putty with a Custom Polymer Matrix

    John Curley


    Full Text Available With the rising tide of antibiotic resistant bacteria, extending the longevity of the current antibiotic arsenal is becoming a necessity. Developing local, controlled release antibiotic strategies, particularly for difficult to penetrate tissues such as bone, may prove to be a better alternative. Previous efforts to develop an osteoconductive local antibiotic release device for bone were created as solid molded composites; however, intimate contact with host bone was found to be critical to support host bone regrowth; thus, an osteocondconductive antibiotic releasing bone void filling putty was developed. Furthermore, a controlled releasing polymer matrix was refined using pendant-functionalized diols to provide tailorable pharmacokinetics. In vitro pharmacokinetic and bioactivity profiles were compared for a putty formulation with an analogous composition as its molded counterpart as well as four new pendant-functionalized polymers. A best-fit analysis of polymer composition in either small cylindrical disks or larger spheres revealed that the new pendant-functionalized polymers appear to release vancomycin via both diffusion and erosion regardless of the geometry of the putty. In silico simulations, a valuable technique for diffusion mediated controlled release models, will be used to confirm and optimize this property.

  7. Pesticide-Exposure Matrix

    The "Pesticide-exposure Matrix" was developed to help epidemiologists and other researchers identify the active ingredients to which people were likely exposed when their homes and gardens were treated for pests in past years.

  8. Matrix theory of gravitation

    Koehler, Wolfgang


    A new classical theory of gravitation within the framework of general relativity is presented. It is based on a matrix formulation of four-dimensional Riemann-spaces and uses no artificial fields or adjustable parameters. The geometrical stress-energy tensor is derived from a matrix-trace Lagrangian, which is not equivalent to the curvature scalar R. To enable a direct comparison with the Einstein-theory a tetrad formalism is utilized, which shows similarities to teleparallel gravitation theories, but uses complex tetrads. Matrix theory might solve a 27-year-old, fundamental problem of those theories (sec. 4.1). For the standard test cases (PPN scheme, Schwarzschild-solution) no differences to the Einstein-theory are found. However, the matrix theory exhibits novel, interesting vacuum solutions.

  9. Matrix comparison, Part 2

    Schneider, Jesper Wiborg; Borlund, Pia


    The present two-part article introduces matrix comparison as a formal means for evaluation purposes in informetric studies such as cocitation analysis. In the first part, the motivation behind introducing matrix comparison to informetric studies, as well as two important issues influencing...... such comparisons, matrix generation, and the composition of proximity measures, are introduced and discussed. In this second part, the authors introduce and thoroughly demonstrate two related matrix comparison techniques the Mantel test and Procrustes analysis, respectively. These techniques can compare...... important. Alternatively, or as a supplement, Procrustes analysis compares the actual ordination results without investigating the underlying proximity measures, by matching two configurations of the same objects in a multidimensional space. An advantage of the Procrustes analysis though, is the graphical...

  10. Controlling frustrated liquids and solids with an applied field in a kagome Heisenberg antiferromagnet.

    Nishimoto, Satoshi; Shibata, Naokazu; Hotta, Chisa


    Quantum spin-1/2 kagome Heisenberg antiferromagnet is the representative frustrated system possibly hosting a spin liquid. Clarifying the nature of this elusive topological phase is a key challenge in condensed matter; however, even identifying it still remains unsettled. Here we apply a magnetic field and discover a series of spin-gapped phases appearing at five different fractions of magnetization by means of a grand canonical density matrix renormalization group, an unbiased state-of-the-art numerical technique. The magnetic field dopes magnons and first gives rise to a possible Z₃ spin liquid plateau at 1/9 magnetization. Higher field induces a self-organized super-lattice unit, a six-membered ring of quantum spins, resembling an atomic orbital structure. Putting magnons into this unit one by one yields three quantum solid plateaus. We thus find that the magnetic field could control the transition between various emergent phases by continuously releasing the frustration.

  11. Electrical transport in RbCl-Al{sub 2}O{sub 3} composite solid electrolytes

    Kumar, A.; Shahi, K. [Indian Inst. of Technology, Kanpur (India). Dept. of Materials Science


    The composite solid electrolytes RbCl-{chi} mole percent (m/o) Al{sub 2}O{sub 3} (0 {<=} x {<=} 50) prepared by conventional powder metallurgy and solution casting processes, have been investigated by impedance analysis, x-ray diffraction (XRD), differential thermal analysis (DTA), and scanning electron microscopy (SEM). The composites prepared by the former method exhibit about an order of magnitude lower conductivity than those prepared by the latter technique. The XRD and DT-A results show that no phases other than RbCl and Al{sub 2}O{sub 3}, are present in the composites, SEM results show that RbCl grains are interspersed with Al{sub 2}O{sub 3} particles. The conductivity of dispersed systems depends on the processing, particle size, and concentration of Al{sub 2}O{sub 3}. The mechanism of enhanced conductivity is proposed to be the generation of excess Rb{sup +} for, vacancies in the host matrix at the matrix-particle interface. Macroscopically the results are explained satisfactorily on the basis of random resistor network model by assuming the formation of high conducting space charge layer along the matrix-particle interface.

  12. The Matrix Organization Revisited

    Gattiker, Urs E.; Ulhøi, John Parm


    This paper gives a short overview of matrix structure and technology management. It outlines some of the characteristics and also points out that many organizations may actualy be hybrids (i.e. mix several ways of organizing to allocate resorces effectively).......This paper gives a short overview of matrix structure and technology management. It outlines some of the characteristics and also points out that many organizations may actualy be hybrids (i.e. mix several ways of organizing to allocate resorces effectively)....

  13. Optical Coherency Matrix Tomography


    optics has been studied theoretically11, but has not been demonstrated experimentally heretofore. Even in the simplest case of two binary DoFs6 (e.g...coherency matrix G spanning these DoFs. This optical coherency matrix has not been measured in its entirety to date—even in the simplest case of two...dense coding, etc. CREOL, The College of Optics & Photonics, University of Central Florida, Orlando , Florida 32816, USA. Correspondence and requests

  14. Matrix fractional systems

    Tenreiro Machado, J. A.


    This paper addresses the matrix representation of dynamical systems in the perspective of fractional calculus. Fractional elements and fractional systems are interpreted under the light of the classical Cole-Cole, Davidson-Cole, and Havriliak-Negami heuristic models. Numerical simulations for an electrical circuit enlighten the results for matrix based models and high fractional orders. The conclusions clarify the distinction between fractional elements and fractional systems.

  15. Hacking the Matrix.

    Czerwinski, Michael; Spence, Jason R


    Recently in Nature, Gjorevski et al. (2016) describe a fully defined synthetic hydrogel that mimics the extracellular matrix to support in vitro growth of intestinal stem cells and organoids. The hydrogel allows exquisite control over the chemical and physical in vitro niche and enables identification of regulatory properties of the matrix. Copyright © 2017 Elsevier Inc. All rights reserved.

  16. The Matrix Organization Revisited

    Gattiker, Urs E.; Ulhøi, John Parm


    This paper gives a short overview of matrix structure and technology management. It outlines some of the characteristics and also points out that many organizations may actualy be hybrids (i.e. mix several ways of organizing to allocate resorces effectively).......This paper gives a short overview of matrix structure and technology management. It outlines some of the characteristics and also points out that many organizations may actualy be hybrids (i.e. mix several ways of organizing to allocate resorces effectively)....

  17. Determination of ochratoxin A in cereal by high performance liquid chromatography with matrix solid-phase dispersion cleaning%基质分散固相萃取净化液相色谱检测谷物中赭曲霉毒素A

    李尧; 张雪梅; 党献民; 任正东; 刘旭; 龚珊; 呼鑫


    To establish a method of extraction with matrix solid-phase dispersion (MSPD), high performance liquid chromatography ( HPLC) coupled with fluorescence detection for determination of ochratoxin A (OTA) in cereal. C18 solid-phase and samples powder placed in the mortar gently and fully mixed by pestle. And then put in glass syringes with sieve plate,rinsed by 10 ml methanohand collect the eluent through 0. 45 μm membrane filter. The filtrate analysis by high performance liquid chromatography coupled with fluorescence detection. The results showed that ochratoxin A in cereal can be an effective separation in selected conditions,recovery rate is between 80. 0% to 93. 65% .the limit of detection is 0. 5 μg/kg. These indicated that this method could detect the additive contents of ochratoxin A in cereal,accurately and simultaneously.%建立了经基质分散固相萃取(MSPD)净化,使用液相色谱仪配荧光检测器分析谷物中赭曲霉毒素A含量的方法.C18固定相与粉碎后的样品置于研钵中,使用研棒轻柔的充分混合,将研磨后的混合物置于带有筛板的玻璃注射器管中,用10 ml甲醇淋洗、定容,收集淋洗液经过0.45 μm滤膜过滤.滤液直接使用配有荧光检测器(FLD)液相色谱仪分析.结果显示,在选定色谱条件下,方法对谷物中含有的赭曲霉毒素A可以有效分离.回收率为80.0%~93.65%,最低检测限为0.5μg/kg.表明该方法能够快速、准确地检测谷物中赭曲霉毒素A的含量.

  18. Characterization of exoplanet hosts

    Valenti Jeff A.


    Full Text Available Spectroscopic analysis of exoplanet hosts and the stellar sample from which they are drawn provides abundances and other properties that quantitively constrain models of planet formation. The program Spectroscopy Made Easy (SME determines stellar parameters by fitting observed spectra, though line lists must be selected wisely. For giant planets, it is now well established that stars with higher metallicity are more likely to have detected companions. Stellar metallicity does not seem to affect the formation and/or migration of detectable planets less massive than Neptune, especially when considering only the most massive planet in the system. In systems with at least one planet less than 10 times the mass of Earth, the mass of the most massive planet increases dramatically with host star metallicity. This may reflect metallicity dependent timescales for core formation, envelope accretion, and/or migration into the detection zone.

  19. HostPhinder: A Phage Host Prediction Tool

    Villarroel, Julia; Kleinheinz, Kortine Annina; Jurtz, Vanessa Isabell


    The current dramatic increase of antibiotic resistant bacteria has revitalised the interest in bacteriophages as alternative antibacterial treatment. Meanwhile, the development of bioinformatics methods for analysing genomic data places high-throughput approaches for phage characterization within...... reach. Here, we present HostPhinder, a tool aimed at predicting the bacterial host of phages by examining the phage genome sequence. Using a reference database of 2196 phages with known hosts, HostPhinder predicts the host species of a query phage as the host of the most genomically similar reference...... phages. As a measure of genomic similarity the number of co-occurring k-mers (DNA sequences of length k) is used. Using an independent evaluation set, HostPhinder was able to correctly predict host genus and species for 81% and 74% of the phages respectively, giving predictions for more phages than BLAST...

  20. Solid aneurysmal bone cyst in the humerus

    Yamamoto, Tetsuji; Marui, Takashi; Akisue, Toshihiro; Mizuno, Kosaku [Dept. of Orthopaedic Surgery, Kobe University School of Medicine, Chuo-Ku (Japan)


    We report on a 69-year-old woman with a solid variant of aneurysmal bone cyst (solid ABC) in the left humerus with a pathological fracture. Radiographically, the lesion exhibited a relatively well-defined osteolytic lesion in the diaphysis of the left humerus. On magnetic resonance (MR) imaging, the medullary lesion exhibited a homogeneous signal intensity isointense with surrounding normal muscles on the T1-weighted images and a mixture of low and high signal intensity on the T2-weighted images. Contrast-enhanced T1-weighted images revealed diffuse enhancement of the entire lesion. The pathological study showed a proliferation of fibroblasts, histiocytes, chronic inflammatory cells and numerous multinucleated giant cells in a collagenous matrix. Abundant osteoid formation in the matrix was observed, but the cells were devoid of nuclear atypia. Aneurysmal cystic cavities were absent. A review of the English literature found 22 cases of solid ABC of the long bones. (orig.)

  1. Matrix Information Geometry

    Bhatia, Rajendra


    This book is an outcome of the Indo-French Workshop on Matrix Information Geometries (MIG): Applications in Sensor and Cognitive Systems Engineering, which was held in Ecole Polytechnique and Thales Research and Technology Center, Palaiseau, France, in February 23-25, 2011. The workshop was generously funded by the Indo-French Centre for the Promotion of Advanced Research (IFCPAR).  During the event, 22 renowned invited french or indian speakers gave lectures on their areas of expertise within the field of matrix analysis or processing. From these talks, a total of 17 original contribution or state-of-the-art chapters have been assembled in this volume. All articles were thoroughly peer-reviewed and improved, according to the suggestions of the international referees. The 17 contributions presented  are organized in three parts: (1) State-of-the-art surveys & original matrix theory work, (2) Advanced matrix theory for radar processing, and (3) Matrix-based signal processing applications.  

  2. Fast acquisition of multidimensional NMR spectra of solids and mesophases using alternative sampling methods.

    Lesot, Philippe; Kazimierczuk, Krzysztof; Trébosc, Julien; Amoureux, Jean-Paul; Lafon, Olivier


    Unique information about the atom-level structure and dynamics of solids and mesophases can be obtained by the use of multidimensional nuclear magnetic resonance (NMR) experiments. Nevertheless, the acquisition of these experiments often requires long acquisition times. We review here alternative sampling methods, which have been proposed to circumvent this issue in the case of solids and mesophases. Compared to the spectra of solutions, those of solids and mesophases present some specificities because they usually display lower signal-to-noise ratios, non-Lorentzian line shapes, lower spectral resolutions and wider spectral widths. We highlight herein the advantages and limitations of these alternative sampling methods. A first route to accelerate the acquisition time of multidimensional NMR spectra consists in the use of sparse sampling schemes, such as truncated, radial or random sampling ones. These sparsely sampled datasets are generally processed by reconstruction methods differing from the Discrete Fourier Transform (DFT). A host of non-DFT methods have been applied for solids and mesophases, including the G-matrix Fourier transform, the linear least-square procedures, the covariance transform, the maximum entropy and the compressed sensing. A second class of alternative sampling consists in departing from the Jeener paradigm for multidimensional NMR experiments. These non-Jeener methods include Hadamard spectroscopy as well as spatial or orientational encoding of the evolution frequencies. The increasing number of high field NMR magnets and the development of techniques to enhance NMR sensitivity will contribute to widen the use of these alternative sampling methods for the study of solids and mesophases in the coming years.

  3. Quantum Diffusion-Controlled Chemistry: Reactions of Atomic Hydrogen with Nitric Oxide in Solid Parahydrogen.

    Ruzi, Mahmut; Anderson, David T


    Our group has been working to develop parahydrogen (pH2) matrix isolation spectroscopy as a method to study low-temperature condensed-phase reactions of atomic hydrogen with various reaction partners. Guided by the well-defined studies of cold atom chemistry in rare-gas solids, the special properties of quantum hosts such as solid pH2 afford new opportunities to study the analogous chemical reactions under quantum diffusion conditions in hopes of discovering new types of chemical reaction mechanisms. In this study, we present Fourier transform infrared spectroscopic studies of the 193 nm photoinduced chemistry of nitric oxide (NO) isolated in solid pH2 over the 1.8 to 4.3 K temperature range. Upon short-term in situ irradiation the NO readily undergoes photolysis to yield HNO, NOH, NH, NH3, H2O, and H atoms. We map the postphotolysis reactions of mobile H atoms with NO and document first-order growth in HNO and NOH reaction products for up to 5 h after photolysis. We perform three experiments at 4.3 K and one at 1.8 K to permit the temperature dependence of the reaction kinetics to be quantified. We observe Arrhenius-type behavior with a pre-exponential factor of A = 0.036(2) min(-1) and Ea = 2.39(1) cm(-1). This is in sharp contrast to previous H atom reactions we have studied in solid pH2 that display definitively non-Arrhenius behavior. The contrasting temperature dependence measured for the H + NO reaction is likely related to the details of H atom quantum diffusion in solid pH2 and deserves further study.

  4. Illuminating coronavirus-host interactions

    Raaben, M.


    Viruses are infectious agents incapable of growing or reproducing outside a host cell. They are completely dependent on the cellular machinery of the host for their multiplication. On the other hand, however, viruses also have to deal with the immune defences of the host. Apparently, viruses are wal

  5. Ceramic Matrix Composites .

    J. Mukerji


    Full Text Available The present state of the knowledge of ceramic-matrix composites have been reviewed. The fracture toughness of present structural ceramics are not enough to permit design of high performance machines with ceramic parts. They also fail by catastrophic brittle fracture. It is generally believed that further improvement of fracture toughness is only possible by making composites of ceramics with ceramic fibre, particulate or platelets. Only ceramic-matrix composites capable of working above 1000 degree centigrade has been dealt with keeping reinforced plastics and metal-reinforced ceramics outside the purview. The author has discussed the basic mechanisms of toughening and fabrication of composites and the difficulties involved. Properties of available fibres and whiskers have been given. The best results obtained so far have been indicated. The limitations of improvement in properties of ceramic-matrix composites have been discussed.

  6. Matrix interdiction problem

    Pan, Feng [Los Alamos National Laboratory; Kasiviswanathan, Shiva [Los Alamos National Laboratory


    In the matrix interdiction problem, a real-valued matrix and an integer k is given. The objective is to remove k columns such that the sum over all rows of the maximum entry in each row is minimized. This combinatorial problem is closely related to bipartite network interdiction problem which can be applied to prioritize the border checkpoints in order to minimize the probability that an adversary can successfully cross the border. After introducing the matrix interdiction problem, we will prove the problem is NP-hard, and even NP-hard to approximate with an additive n{gamma} factor for a fixed constant {gamma}. We also present an algorithm for this problem that achieves a factor of (n-k) mUltiplicative approximation ratio.

  7. Extracellular matrix structure.

    Theocharis, Achilleas D; Skandalis, Spyros S; Gialeli, Chrysostomi; Karamanos, Nikos K


    Extracellular matrix (ECM) is a non-cellular three-dimensional macromolecular network composed of collagens, proteoglycans/glycosaminoglycans, elastin, fibronectin, laminins, and several other glycoproteins. Matrix components bind each other as well as cell adhesion receptors forming a complex network into which cells reside in all tissues and organs. Cell surface receptors transduce signals into cells from ECM, which regulate diverse cellular functions, such as survival, growth, migration, and differentiation, and are vital for maintaining normal homeostasis. ECM is a highly dynamic structural network that continuously undergoes remodeling mediated by several matrix-degrading enzymes during normal and pathological conditions. Deregulation of ECM composition and structure is associated with the development and progression of several pathologic conditions. This article emphasizes in the complex ECM structure as to provide a better understanding of its dynamic structural and functional multipotency. Where relevant, the implication of the various families of ECM macromolecules in health and disease is also presented.

  8. Finite Temperature Matrix Theory

    Meana, M L; Peñalba, J P; Meana, Marco Laucelli; Peñalba, Jesús Puente


    We present the way the Lorentz invariant canonical partition function for Matrix Theory as a light-cone formulation of M-theory can be computed. We explicitly show how when the eleventh dimension is decompactified, the N=1 eleven dimensional SUGRA partition function appears. From this particular analysis we also clarify the question about the discernibility problem when making statistics with supergravitons (the N! problem) in Matrix black hole configurations. We also provide a high temperature expansion which captures some structure of the canonical partition function when interactions amongst D-particles are on. The connection with the semi-classical computations thermalizing the open superstrings attached to a D-particle is also clarified through a Born-Oppenheimer approximation. Some ideas about how Matrix Theory would describe the complementary degrees of freedom of the massless content of eleven dimensional SUGRA are also discussed.

  9. Surface-associated plasminogen binding of Cryptococcus neoformans promotes extracellular matrix invasion.

    Jamal Stie

    Full Text Available BACKGROUND: The fungal pathogen Cryptococcus neoformans is a leading cause of illness and death in persons with predisposing factors, including: malignancies, solid organ transplants, and corticosteroid use. C. neoformans is ubiquitous in the environment and enters into the lungs via inhalation, where it can disseminate through the bloodstream and penetrate the central nervous system (CNS, resulting in a difficult to treat and often-fatal infection of the brain, called meningoencephalitis. Plasminogen is a highly abundant protein found in the plasma component of blood and is necessary for the degradation of fibrin, collagen, and other structural components of tissues. This fibrinolytic system is utilized by cancer cells during metastasis and several pathogenic species of bacteria have been found to manipulate the host plasminogen system to facilitate invasion of tissues during infection by modifying the activation of this process through the binding of plasminogen at their surface. METHODOLOGY: The invasion of the brain and the central nervous system by penetration of the protective blood-brain barrier is a prerequisite to the establishment of meningoencephalitis by the opportunistic fungal pathogen C. neoformans. In this study, we examined the ability of C. neoformans to subvert the host plasminogen system to facilitate tissue barrier invasion. Through a combination of biochemical, cell biology, and proteomic approaches, we have shown that C. neoformans utilizes the host plasminogen system to cross tissue barriers, providing support for the hypothesis that plasminogen-binding may contribute to the invasion of the blood-brain barrier by penetration of the brain endothelial cells and underlying matrix. In addition, we have identified the cell wall-associated proteins that serve as plasminogen receptors and characterized both the plasminogen-binding and plasmin-activation potential for this significant human pathogen. CONCLUSIONS: The results of

  10. HostPhinder: A Phage Host Prediction Tool

    Julia Villarroel


    Full Text Available The current dramatic increase of antibiotic resistant bacteria has revitalised the interest in bacteriophages as alternative antibacterial treatment. Meanwhile, the development of bioinformatics methods for analysing genomic data places high-throughput approaches for phage characterization within reach. Here, we present HostPhinder, a tool aimed at predicting the bacterial host of phages by examining the phage genome sequence. Using a reference database of 2196 phages with known hosts, HostPhinder predicts the host species of a query phage as the host of the most genomically similar reference phages. As a measure of genomic similarity the number of co-occurring k-mers (DNA sequences of length k is used. Using an independent evaluation set, HostPhinder was able to correctly predict host genus and species for 81% and 74% of the phages respectively, giving predictions for more phages than BLAST and significantly outperforming BLAST on phages for which both had predictions. HostPhinder predictions on phage draft genomes from the INTESTI phage cocktail corresponded well with the advertised targets of the cocktail. Our study indicates that for most phages genomic similarity correlates well with related bacterial hosts. HostPhinder is available as an interactive web service [1] and as a stand alone download from the Docker registry [2].

  11. Vibrational relaxation and energy transfer of matrix isolated HCl and DCl

    Wiesenfeld, J.M.


    Vibrational kinetic and spectroscopic studies have been performed on matrix-isolated HCl and DCl between 9 and 20 K. Vibrational relaxation rates for v = 2 and v = 1 were measured by a tunable infrared laser-induced, time-resolved fluorescence technique. In an Ar matrix, vibrational decay times are faster than radiative and it is found that HCl relaxes about 35 times more rapidly than CCl, in spite of the fact that HCl must transfer more energy to the lattice than DCl. This result is explained by postulating that the rate-determining step for vibrational relaxation produces a highly rotationally excited guest in a V yield R step; rotational relaxation into lattice phonons follows rapidly. HCl v = 1, but not v = 2, excitation rapidly diffuses through the sample by a resonant dipole-dipole vibrational energy transfer process. Molecular complexes, and in particular the HCl dimer, relax too rapidly for direct observation, less than or approximately 1, and act as energy sinks in the energy diffusion process. The temperature dependence for all these processes is weak--less than a factor of two between 9 and 20 K. Vibrational relaxation of HCl in N/sub 2/ and O/sub 2/ matrices is unobservable, presumably due to rapid V yield V transfer to the host. A V yield R binary collision model for relaxation in solids is successful in explaining the HCl(DCl)/Ar results as well as results of other experimenters. The model considers relaxation to be the result of ''collisions'' due to molecular motion in quantized lattice normal modes--gas phase potential parameters can fit the matrix kinetic data.

  12. Matrix fluid chemistry experiment. Final report June 1998 - March 2003

    Smellie, John A.T. [Conterra AB, Luleaa (Sweden); Waber, H. Niklaus [Univ. of Bern (Switzerland). Inst. of Geology; Frape, Shaun K. [Univ. of Waterloo (Canada). Dept. of Earth Sciences


    The Matrix Fluid Chemistry Experiment set out to determine the composition and evolution of matrix pore fluids/waters in low permeable rock located at repository depths in the Aespoe Hard Rock Laboratory (HRL). Matrix pore fluids/waters can be highly saline in composition and, if accessible, may influence the near-field groundwater chemistry of a repository system. Characterising pore fluids/waters involved in-situ borehole sampling and analysis integrated with laboratory studies and experiments on rock matrix drill core material. Relating the rate of in-situ pore water accumulation during sampling to the measured rock porosity indicated a hydraulic conductivity of 10{sup -14}-10{sup -13} m/s for the rock matrix. This was in accordance with earlier estimated predictions. The sampled matrix pore water, brackish in type, mostly represents older palaeo- groundwater mixtures preserved in the rock matrix and dating back to at least the last glaciation. A component of matrix pore 'fluid' is also present. One borehole section suggests a younger groundwater component which has accessed the rock matrix during the experiment. There is little evidence that the salinity of the matrix pore waters has been influenced significantly by fluid inclusion populations hosted by quartz. Crush/leach, cation exchange, pore water diffusion and pore water displacement laboratory experiments were carried out to compare extracted/calculated matrix pore fluids/waters with in-situ sampling. Of these the pore water diffusion experiments appear to be the most promising approach and a recommended site characterisation protocol has been formulated. The main conclusions from the Matrix Fluid Chemistry Experiment are: Groundwater movement within the bedrock hosting the experimental site has been enhanced by increased hydraulic gradients generated by the presence of the tunnel, and to a much lesser extent by the borehole itself. Over experimental timescales {approx}4 years) solute transport

  13. Matrixed business support comparison study.

    Parsons, Josh D.


    The Matrixed Business Support Comparison Study reviewed the current matrixed Chief Financial Officer (CFO) division staff models at Sandia National Laboratories. There were two primary drivers of this analysis: (1) the increasing number of financial staff matrixed to mission customers and (2) the desire to further understand the matrix process and the opportunities and challenges it creates.

  14. Reliability analysis of ceramic matrix composite laminates

    Thomas, David J.; Wetherhold, Robert C.


    At a macroscopic level, a composite lamina may be considered as a homogeneous orthotropic solid whose directional strengths are random variables. Incorporation of these random variable strengths into failure models, either interactive or non-interactive, allows for the evaluation of the lamina reliability under a given stress state. Using a non-interactive criterion for demonstration purposes, laminate reliabilities are calculated assuming previously established load sharing rules for the redistribution of load as the failure of laminae occur. The matrix cracking predicted by ACK theory is modeled to allow a loss of stiffness in the fiber direction. The subsequent failure in the fiber direction is controlled by a modified bundle theory. Results using this modified bundle model are compared with previous models which did not permit separate consideration of matrix cracking, as well as to results obtained from experimental data.

  15. IIB Matrix Model

    Aoki, H; Kawai, H; Kitazawa, Y; Tada, T; Tsuchiya, A


    We review our proposal for a constructive definition of superstring, type IIB matrix model. The IIB matrix model is a manifestly covariant model for space-time and matter which possesses N=2 supersymmetry in ten dimensions. We refine our arguments to reproduce string perturbation theory based on the loop equations. We emphasize that the space-time is dynamically determined from the eigenvalue distributions of the matrices. We also explain how matter, gauge fields and gravitation appear as fluctuations around dynamically determined space-time.

  16. Little IIB Matrix Model

    Kitazawa, Y; Saito, O; Kitazawa, Yoshihisa; Mizoguchi, Shun'ya; Saito, Osamu


    We study the zero-dimensional reduced model of D=6 pure super Yang-Mills theory and argue that the large N limit describes the (2,0) Little String Theory. The one-loop effective action shows that the force exerted between two diagonal blocks of matrices behaves as 1/r^4, implying a six-dimensional spacetime. We also observe that it is due to non-gravitational interactions. We construct wave functions and vertex operators which realize the D=6, (2,0) tensor representation. We also comment on other "little" analogues of the IIB matrix model and Matrix Theory with less supercharges.

  17. Elementary matrix algebra

    Hohn, Franz E


    This complete and coherent exposition, complemented by numerous illustrative examples, offers readers a text that can teach by itself. Fully rigorous in its treatment, it offers a mathematically sound sequencing of topics. The work starts with the most basic laws of matrix algebra and progresses to the sweep-out process for obtaining the complete solution of any given system of linear equations - homogeneous or nonhomogeneous - and the role of matrix algebra in the presentation of useful geometric ideas, techniques, and terminology.Other subjects include the complete treatment of the structur

  18. Reduced Google matrix

    Frahm, K M


    Using parallels with the quantum scattering theory, developed for processes in nuclear and mesoscopic physics and quantum chaos, we construct a reduced Google matrix $G_R$ which describes the properties and interactions of a certain subset of selected nodes belonging to a much larger directed network. The matrix $G_R$ takes into account effective interactions between subset nodes by all their indirect links via the whole network. We argue that this approach gives new possibilities to analyze effective interactions in a group of nodes embedded in a large directed networks. Possible efficient numerical methods for the practical computation of $G_R$ are also described.

  19. Density matrix perturbation theory.

    Niklasson, Anders M N; Challacombe, Matt


    An orbital-free quantum perturbation theory is proposed. It gives the response of the density matrix upon variation of the Hamiltonian by quadratically convergent recursions based on perturbed projections. The technique allows treatment of embedded quantum subsystems with a computational cost scaling linearly with the size of the perturbed region, O(N(pert.)), and as O(1) with the total system size. The method allows efficient high order perturbation expansions, as demonstrated with an example involving a 10th order expansion. Density matrix analogs of Wigner's 2n+1 rule are also presented.

  20. Complex matrix model duality

    Brown, T.W.


    The same complex matrix model calculates both tachyon scattering for the c=1 non-critical string at the self-dual radius and certain correlation functions of half-BPS operators in N=4 super- Yang-Mills. It is dual to another complex matrix model where the couplings of the first model are encoded in the Kontsevich-like variables of the second. The duality between the theories is mirrored by the duality of their Feynman diagrams. Analogously to the Hermitian Kontsevich- Penner model, the correlation functions of the second model can be written as sums over discrete points in subspaces of the moduli space of punctured Riemann surfaces. (orig.)

  1. The Drosophila melanogaster host model

    Igboin, Christina O.; Griffen, Ann L.; Leys, Eugene J.


    The deleterious and sometimes fatal outcomes of bacterial infectious diseases are the net result of the interactions between the pathogen and the host, and the genetically tractable fruit fly, Drosophila melanogaster, has emerged as a valuable tool for modeling the pathogen–host interactions of a wide variety of bacteria. These studies have revealed that there is a remarkable conservation of bacterial pathogenesis and host defence mechanisms between higher host organisms and Drosophila. This review presents an in-depth discussion of the Drosophila immune response, the Drosophila killing model, and the use of the model to examine bacterial–host interactions. The recent introduction of the Drosophila model into the oral microbiology field is discussed, specifically the use of the model to examine Porphyromonas gingivalis–host interactions, and finally the potential uses of this powerful model system to further elucidate oral bacterial-host interactions are addressed. PMID:22368770

  2. The Drosophila melanogaster host model

    Christina O. Igboin


    Full Text Available The deleterious and sometimes fatal outcomes of bacterial infectious diseases are the net result of the interactions between the pathogen and the host, and the genetically tractable fruit fly, Drosophila melanogaster, has emerged as a valuable tool for modeling the pathogen–host interactions of a wide variety of bacteria. These studies have revealed that there is a remarkable conservation of bacterial pathogenesis and host defence mechanisms between higher host organisms and Drosophila. This review presents an in-depth discussion of the Drosophila immune response, the Drosophila killing model, and the use of the model to examine bacterial–host interactions. The recent introduction of the Drosophila model into the oral microbiology field is discussed, specifically the use of the model to examine Porphyromonas gingivalis–host interactions, and finally the potential uses of this powerful model system to further elucidate oral bacterial-host interactions are addressed.

  3. Dynamic Matrix Rank

    Frandsen, Gudmund Skovbjerg; Frandsen, Peter Frands


    We consider maintaining information about the rank of a matrix under changes of the entries. For n×n matrices, we show an upper bound of O(n1.575) arithmetic operations and a lower bound of Ω(n) arithmetic operations per element change. The upper bound is valid when changing up to O(n0.575) entri...... closed fields. The upper bound for element updates uses fast rectangular matrix multiplication, and the lower bound involves further development of an earlier technique for proving lower bounds for dynamic computation of rational functions.......We consider maintaining information about the rank of a matrix under changes of the entries. For n×n matrices, we show an upper bound of O(n1.575) arithmetic operations and a lower bound of Ω(n) arithmetic operations per element change. The upper bound is valid when changing up to O(n0.575) entries...... in a single column of the matrix. We also give an algorithm that maintains the rank using O(n2) arithmetic operations per rank one update. These bounds appear to be the first nontrivial bounds for the problem. The upper bounds are valid for arbitrary fields, whereas the lower bound is valid for algebraically...

  4. Empirical codon substitution matrix

    Gonnet Gaston H


    Full Text Available Abstract Background Codon substitution probabilities are used in many types of molecular evolution studies such as determining Ka/Ks ratios, creating ancestral DNA sequences or aligning coding DNA. Until the recent dramatic increase in genomic data enabled construction of empirical matrices, researchers relied on parameterized models of codon evolution. Here we present the first empirical codon substitution matrix entirely built from alignments of coding sequences from vertebrate DNA and thus provide an alternative to parameterized models of codon evolution. Results A set of 17,502 alignments of orthologous sequences from five vertebrate genomes yielded 8.3 million aligned codons from which the number of substitutions between codons were counted. From this data, both a probability matrix and a matrix of similarity scores were computed. They are 64 × 64 matrices describing the substitutions between all codons. Substitutions from sense codons to stop codons are not considered, resulting in block diagonal matrices consisting of 61 × 61 entries for the sense codons and 3 × 3 entries for the stop codons. Conclusion The amount of genomic data currently available allowed for the construction of an empirical codon substitution matrix. However, more sequence data is still needed to construct matrices from different subsets of DNA, specific to kingdoms, evolutionary distance or different amount of synonymous change. Codon mutation matrices have advantages for alignments up to medium evolutionary distances and for usages that require DNA such as ancestral reconstruction of DNA sequences and the calculation of Ka/Ks ratios.

  5. Matrix Embedded Organic Synthesis

    Kamakolanu, U. G.; Freund, F. T.


    In the matrix of minerals such as olivine, a redox reaction of the low-z elements occurs. Oxygen is oxidized to the peroxy state while the low-Z-elements become chemically reduced. We assign them a formula [CxHyOzNiSj]n- and call them proto-organics.

  6. Measurement of Chiral Recognition Properties of Crown Ethers Using Matrix Assisted Laser Desorption Ionization Mass Spectrometry

    SAWADA, Masami; Harada, Manabu; TAKAI, Yoshio; NAKANO, Kazurou; Kuroda, Masao; ARAKAWA, Ryuichi; 荒川, 隆一


    Hydrogen bonding host-guest complex ions between chiral crown ethers and chiral amino acid ester salts, detected by matrix assisted laser desorption ionization (MALDI) mass spectrometry (MS) with a DHBA or MSA matrix, were studied on the view point of chiral recognition properties of the chiral crown hosts. The chiral recognition property (IR/IS-dn value≅1.0) obtained by the present MALDI-MS is sharply different from the IR/IS-dn value obtained by FAB-MS or ESI-MS (≠1.0) in the same host-gues...

  7. Recent advances in laser cooling of solids

    Nemova, Galina; Kashyap, Raman


    The recent achievements devoted to cooling of solids with a laser are presented in this paper. We discuss the latest results of traditional laser cooling of solids based on rare earth ions and new techniques based on colloidal lead-salt quantum dots doped in a glass host, laser cooling in Tm3+-doped oxy-fluoride glass ceramic. Relatively short (microsecond) lifetime of the excited level of the PbSe QDs compared to the millisecond lifetime of the excited level of RE ions allows an acceleration of the cooling process and provides an opportunity to use new materials with higher phonon energy as hosts, which are normally considered unsuitable for cooling with RE ions. Another new approach to the laser cooling problem based on super-radiance has been considered in this paper. The advantages of optical refrigeration with rare earth doped semiconductors, in which not only optically active electrons of the 4f shell but the valence and conduction bands of the host material are involved in cooling cycle is discussed. It is shown that involving the valence and conduction bands of the host in the cooling cycle allows the pump wavelength to be shorter than mean fluorescence wavelength. Raman laser cooling of solids as well as observation of spontaneous Brillouin cooling have been presented.

  8. Statics of deformable solids

    Bisplinghoff, Raymond L; Pian, Theodore HH


    Profusely illustrated exposition of fundamentals of solid mechanics and principles of mechanics, statics, and simple statically indeterminate systems. Covers strain and stress in three-dimensional solids, elementary elasticity, energy principles in solid continuum, and more. 1965 edition.

  9. Measuring the pollutant transport capacity of dissolved organic matter in complex matrixes

    Persson, L.; Alsberg, T.; Odham, G.


    were used and evaluated, head-space solid-phase micro-extraction (HS-SPME), enhanced solubility (ES) and fluorescence quenching (FQ). It was concluded that for samples with complex matrixes it was possible to measure the net effect of the DOM binding capacity and the salting out effect of the matrix...

  10. Cell-extracellular matrix and cell-cell adhesion are linked by syndecan-4

    Pakideeri Karat, Sandeep Gopal; Multhaupt, Hinke A B; Pocock, Roger


    Cell-extracellular matrix (ECM) and cell-cell junctions that employ microfilaments are sites of tension. They are important for tissue repair, morphogenetic movements and can be emblematic of matrix contraction in fibrotic disease and the stroma of solid tumors. One cell surface receptor, syndeca...

  11. Avian host defense peptides.

    Cuperus, Tryntsje; Coorens, Maarten; van Dijk, Albert; Haagsman, Henk P


    Host defense peptides (HDPs) are important effector molecules of the innate immune system of vertebrates. These antimicrobial peptides are also present in invertebrates, plants and fungi. HDPs display broad-spectrum antimicrobial activities and fulfill an important role in the first line of defense of many organisms. It is becoming increasingly clear that in the animal kingdom the functions of HDPs are not confined to direct antimicrobial actions. Research in mammals has indicated that HDPs have many immunomodulatory functions and are also involved in other physiological processes ranging from development to wound healing. During the past five years our knowledge about avian HDPs has increased considerably. This review addresses our current knowledge on the evolution, regulation and biological functions of HDPs of birds.

  12. Host Integration Server 2004

    PaulThurrott; 杨岩


    微软发布的Host Integration Server(HIS)2004,是IBM大型主机集成服务器的一个重要的更新,添加了一些重要的新特点和改进。与大多数微软公司协同工作的产品不同,HIS 2004的设计目的是为了移植,而不是纯粹的集成,事实上它将会帮助客户从现有的传统平台中得到更多的价值——在这种情况下,所指的产品就是IBM大型主机和iSeries(也就是以前的AS/400)系列机型。

  13. Ultrasonic Scattering by an Elastic Sphere in Matrix with Imperfect Interface

    WU Rui-Xin; WANG Yao-Jun


    The general solution of ultrasonic wave scattering by an elastic sphere embedded in solid matrix with an interface layer is developed. A transfer matrix connecting the displacement and stress components on the opposite surfaces of the layer is derived. Asymptotically expanding the transfer matrix gives the equivalent boundary conditions at an interface. A spring model for describing physically a spherical imperfect interface is thus established and its validity is evaluated. Ultrasonic scatterings respectively from rigid and slip interface are numerically compared.

  14. Flow acoustics in solid-fluid structures

    Willatzen, Morten; Mads, Mikhail Vladimirovich Deryabin


    along the x direction. In the first part of the paper, the governing set of differential equations are derived as well as the imposed boundary conditions. Solutions are provided using Hamilton's equations for the wavenumber vs. frequency as a function of the number and thickness of solid layers....... A wavenumber condition for an arbitrary set of consecutive solid and fluid layers, involving four propagating waves in each solid region, is obtained again using the monodromy matrix method. Case examples are finally discussed.......The governing two-dimensional equations of a heterogeneous material composed of a fluid (allowed to flow in the absence of acoustic excitations) and a crystalline piezoelectric cubic solid stacked one-dimensionally (along the z direction) are derived and special emphasis is given to the discussion...

  15. Social Hackers: Integration in the Host Chemical Recognition System by a Paper Wasp Social Parasite

    Turillazzi, S.; Sledge, M. F.; Dani, F. R.; Cervo, R.; Massolo, A.; Fondelli, L.

    Obligate social parasites in the social insects have lost the worker caste and the ability to establish nests. As a result, parasites must usurp a host nest, overcome the host recognition system, and depend on the host workers to rear their offspring. We analysed cuticular hydrocarbon profiles of live parasite females of the paper wasp social parasite Polistes sulcifer before and after usurpation of host nests, using the non-destructive technique of solid-phase micro-extraction. Our results reveal that hydrocarbon profiles of parasites change after usurpation of host nests to match the cuticular profile of the host species. Chemical evidence further shows that the parasite queen changes the odour of the nest by the addition of a parasite-specific hydrocarbon. We discuss the possible role of this in the recognition and acceptance of the parasite and its offspring in the host colony.

  16. Solid-surface luminescence analysis

    Hurtubise, R.J.


    We have characterized several interactions that are very important in solid-matrix luminescence. With silica gel chromatoplates and filter paper, simple equations were derived for calculating the individual contributions to the percent decrease in luminescence due to either moisture or to a quenching gas. For sodium acetate as a solid matrix and p-aminobenzoate as a model compound, it was concluded that p-aminobenzoate was incorporated into the crystal structure of sodium acetate, and the triplet energy was lost be skeletal vibrations in sodium acetate. Also, with the same system is was shown that p-aminobenzoate did not undergo rotational relaxation, and thus rotational processes did not contribute to the deactivation of the triplet state. Several results were obtained from model compounds adsorbed on filter paper under different temperature and humidity conditions and with a variety of heavy atoms present. Fundamental photophysical equations were used in calculating several basic parameters that revealed information on rate processes and how the absorbed energy was distributed in an adsorbed lumiphor. The most important advancement with filter paper was the development of equations that relate phosphorescence parameters of adsorbed phosphors to the Young's modulus of filter paper. These equations are based on a fundamental theory that relates the hydrogen-bonding network of paper to the modulus of paper.

  17. Matrix string theory

    Dijkgraaf, Robbert; Verlinde, Erik; Verlinde, Herman


    Via compactification on a circle, the matrix mode] of M-theory proposed by Banks et a]. suggests a concrete identification between the large N limit of two-dimensional N = 8 supersymmetric Yang-Mills theory and type IIA string theory. In this paper we collect evidence that supports this identification. We explicitly identify the perturbative string states and their interactions, and describe the appearance of D-particle and D-membrane states.

  18. Matrix string theory

    Dijkgraaf, R. [Amsterdam Univ. (Netherlands). Dept. of Mathematics; Verlinde, E. [TH-Division, CERN, CH-1211 Geneva 23 (Switzerland)]|[Institute for Theoretical Physics, Universtity of Utrecht, 3508 TA Utrecht (Netherlands); Verlinde, H. [Institute for Theoretical Physics, University of Amsterdam, 1018 XE Amsterdam (Netherlands)


    Via compactification on a circle, the matrix model of M-theory proposed by Banks et al. suggests a concrete identification between the large N limit of two-dimensional N=8 supersymmetric Yang-Mills theory and type IIA string theory. In this paper we collect evidence that supports this identification. We explicitly identify the perturbative string states and their interactions, and describe the appearance of D-particle and D-membrane states. (orig.).

  19. Matrix String Theory

    Dijkgraaf, R; Verlinde, Herman L


    Via compactification on a circle, the matrix model of M-theory proposed by Banks et al suggests a concrete identification between the large N limit of two-dimensional N=8 supersymmetric Yang-Mills theory and type IIA string theory. In this paper we collect evidence that supports this identification. We explicitly identify the perturbative string states and their interactions, and describe the appearance of D-particle and D-membrane states.

  20. Holomorphic matrix integrals

    Felder, G; Felder, Giovanni; Riser, Roman


    We study a class of holomorphic matrix models. The integrals are taken over middle dimensional cycles in the space of complex square matrices. As the size of the matrices tends to infinity, the distribution of eigenvalues is given by a measure with support on a collection of arcs in the complex planes. We show that the arcs are level sets of the imaginary part of a hyperelliptic integral connecting branch points.

  1. Matrix groups for undergraduates

    Tapp, Kristopher


    Matrix groups touch an enormous spectrum of the mathematical arena. This textbook brings them into the undergraduate curriculum. It makes an excellent one-semester course for students familiar with linear and abstract algebra and prepares them for a graduate course on Lie groups. Matrix Groups for Undergraduates is concrete and example-driven, with geometric motivation and rigorous proofs. The story begins and ends with the rotations of a globe. In between, the author combines rigor and intuition to describe the basic objects of Lie theory: Lie algebras, matrix exponentiation, Lie brackets, maximal tori, homogeneous spaces, and roots. This second edition includes two new chapters that allow for an easier transition to the general theory of Lie groups. From reviews of the First Edition: This book could be used as an excellent textbook for a one semester course at university and it will prepare students for a graduate course on Lie groups, Lie algebras, etc. … The book combines an intuitive style of writing w...

  2. Metal matrix Composites

    Pradeep K. Rohatgi


    Full Text Available This paper reviews the world wide upsurge in metal matrix composite research and development activities with particular emphasis on cast metal-matrix particulate composites. Extensive applications of cast aluminium alloy MMCs in day-to-day use in transportation as well as durable good industries are expected to advance rapidly in the next decade. The potential for extensive application of cast composites is very large in India, especially in the areas of transportation, energy and electromechanical machinery; the extensive use of composites can lead to large savings in materials and energy, and in several instances, reduce environmental pollution. It is important that engineering education and short-term courses be organized to bring MMCs to the attention of students and engineering industry leaders. India already has excellent infrastructure for development of composites, and has a long track record of world class research in cast metal matrix particulate composites. It is now necessary to catalyze prototype and regular production of selected composite components, and get them used in different sectors, especially railways, cars, trucks, buses, scooters and other electromechanical machinery. This will require suitable policies backed up by funding to bring together the first rate talent in cast composites which already exists in India, to form viable development groups followed by setting up of production plants involving the process engineering capability already available within the country. On the longer term, cast composites should be developed for use in energy generation equipment, electronic packaging aerospace systems, and smart structures.

  3. Cavitation instabilities between fibres in a metal matrix composite

    Tvergaard, Viggo


    Short fibre reinforced metal matrix composites (MMC) are studied here to investigate the possibility that a cavitation instability can develop in the metal matrix. The high stress levels needed for a cavitation instability may occur in metal–ceramic systems due to the constraint on plastic flow...... of transversely staggered fibres is here modelled by using an axisymmetric cell model analysis. First the critical stress level is determined for a cavitation instability in an infinite solid made of the Al matrix material. By studying composites with different distributions and aspect ratios of the fibres...... induced by bonding to the ceramics that only show elastic deformation. In an MMC the stress state in the metal matrix is highly non-uniform, varying between regions where shear stresses are dominant and regions where hydrostatic tension is strong. An Al–SiC whisker composite with a periodic pattern...

  4. Correlation of ion-ion interaction with electrical conductivity in solid state polymeric separator for energy storage applications

    Sharma, Parul Kumar; Sadiq, M.; Bhatt, Chandni; Sharma, A. L.


    In the present study, we report innovative study on the prepared high quality solid state free standing thin polymeric separator. In prepared free standing polymeric separator, polymer (PEO) has been used as host matrix; appropriate bulky anion salt (LiPF6) as conducting species and Nano ceramic filler (BaTiO3) is used to enrich the mechanical and thermal stability of separator used for the device applications. The Fourier Transform Infra-Red (FTIR) result has been analysed properly of the prepared materials to look the microscopic interaction among polymer-ion, ion-ion and polymer-ion-clay interaction. Electrical conductivity results has been recorded using the impedance spectroscopy results which gives the estimated value of the order of ˜10-3 Scm-1 of the nano ceramic doped polymeric separator which is desirable for energy storage application. A fine correlation has been established between the obtained results by this two analysis.

  5. Matrix Theory of Small Oscillations

    Chavda, L. K.


    A complete matrix formulation of the theory of small oscillations is presented. Simple analytic solutions involving matrix functions are found which clearly exhibit the transients, the damping factors, the Breit-Wigner form for resonances, etc. (BB)

  6. Probing the microenvironment of an oligo-(p-phenylene vinylene) derivative encapsulated in polymer-impregnated sol-gel silica matrix

    TANG Jun; DU Chuang; YU Xiaoqiang; ZHANG Guo; WANG Ce


    Polymer-impregnated silica sol-gel composite materials are hosts for organics in advanced optics application. An oligo-phenylene vinylene derivative 4,4'-(1,4-phenylene dithenylene)-bis-(N-methyl pyridinium iodide)(OPVD) was introduced to poly(hydroxyethyl methacrylate)(PHEMA)-impregnated silica composite film by the sol-gel process. By comparing the X-ray diffraction, UV-visible spectra, steady-state and time-resolved fluorescence spectra of OPVD in three solid matrices (PHEMA/silica composite film, pure PHEMA film, and pure silica film), the similar results of PHEMA/silica composite film and pure PHEMA film demonstrate that the OPVD is primarily surrounded by a PHEMA-like environment in the composite matrix. The model of such structure is presented, which is useful for further understanding and optimizing of properties of doped sol-gel materials.

  7. Matrix Completions and Chordal Graphs

    Kenneth John HARRISON


    In a matrix-completion problem the aim is to specifiy the missing entries of a matrix inorder to produce a matrix with particular properties. In this paper we survey results concerning matrix-completion problems where we look for completions of various types for partial matrices supported ona given pattern. We see that thc existence of completions of the required type often depends on thechordal properties of graphs associated with the pattern.

  8. Alternative mechanisms of increased eggshell hardness of avian brood parasites relative to host species

    Igic, Branislav; Braganza, Kim; Hyland, Margaret M.; Silyn-Roberts, Heather; Cassey, Phillip; Grim, Tomas; Rutila, Jarkko; Moskát, Csaba; Hauber, Mark E.


    Obligate brood parasitic birds lay their eggs in nests of other species and parasite eggs typically have evolved greater structural strength relative to host eggs. Increased mechanical strength of the parasite eggshell is an adaptation that can interfere with puncture ejection behaviours of discriminating hosts. We investigated whether hardness of eggshells is related to differences between physical and chemical traits from three different races of the parasitic common cuckoo Cuculus canorus, and their respective hosts. Using tools developed for materials science, we discovered a novel correlate of increased strength of parasite eggs: the common cuckoo's egg exhibits a greater microhardness, especially in the inner region of the shell matrix, relative to its host and sympatric non-host species. We then tested predictions of four potential mechanisms of shell strength: (i) increased relative thickness overall, (ii) greater proportion of the structurally harder shell layers, (iii) higher concentration of inorganic components in the shell matrix, and (iv) elevated deposition of a high density compound, MgCO3, in the shell matrix. We confirmed support only for hypothesis (i). Eggshell characteristics did not differ between parasite eggs sampled from different host nests in distant geographical sites, suggesting an evolutionarily shared microstructural mechanism of stronger parasite eggshells across diverse host-races of brood parasitic cuckoos. PMID:21561966


    the Least Square Best Estimate of the Generalized Polarization matrix from a set of measurements is then developed. It is shown that the Faraday...matrix data. It is then shown that the Least Square Best Estimate of the orientation angle of a symmetric target is also determinable from Faraday rotation contaminated short pulse monostatic polarization matrix data.

  10. Solid lubricants and surfaces

    Braithwaite, E R


    Solid Lubricants and Surfaces deals with the theory and use of solid lubricants, particularly in colloidal form. Portions of this book are devoted to graphite and molybdenum disulfides, which are widely used solid lubricants in colloidal form. An extensive literature on the laboratory examination of hundreds of solids as potential lubricants is also provided in this text. Other topics discussed include the metals and solid lubricants; techniques for examining surfaces; other solid lubricants; metal shaping; and industrial uses of solid-lubricant dispersions. This publication is beneficial to e

  11. Experimental study of kinetic and mechanism of dissolution of apatite structured minerals. Application to the prediction of the long term behavior of an actinides storage host matrix; Etude experimentale de la cinetique et des mecanismes d'alteration de mineraux apatitiques. Application au comportement d'une ceramique de confinement d'actinides mineurs

    Chairat, C


    The motivation for this study is to assess the potential of using apatite structured ceramics as long-lived actinide storage hosts. To assess their ability to resist aqueous corrosion, the dissolution of natural fluoro-apatite and synthetic Nd-britholite (neodymium is a proxy for the trivalent actinides) was studied. Mineral surfaces were characterized using a combined spectrometric, electrokinetic and potentiometric approach and dissolution rates were measured in closed and open system reactors as a function of solution composition. Experimental results suggest apatitic minerals dissolve via distinct step sequence: 1) fluoride release, 2) release of the calcium situated in the M1, and 3) the simultaneous removal of phosphate and calcium II via the breaking of only Ca-O bonds. TST based rate equations based in this mechanism accurately describe fluoro-apatite and synthetic britholite dissolution rates as a function of solution composition. Nd release rates are limited by precipitation of Nd-rhabdophane. (author)

  12. The cellulose resource matrix.

    Keijsers, Edwin R P; Yılmaz, Gülden; van Dam, Jan E G


    The emerging biobased economy is causing shifts from mineral fossil oil based resources towards renewable resources. Because of market mechanisms, current and new industries utilising renewable commodities, will attempt to secure their supply of resources. Cellulose is among these commodities, where large scale competition can be expected and already is observed for the traditional industries such as the paper industry. Cellulose and lignocellulosic raw materials (like wood and non-wood fibre crops) are being utilised in many industrial sectors. Due to the initiated transition towards biobased economy, these raw materials are intensively investigated also for new applications such as 2nd generation biofuels and 'green' chemicals and materials production (Clark, 2007; Lange, 2007; Petrus & Noordermeer, 2006; Ragauskas et al., 2006; Regalbuto, 2009). As lignocellulosic raw materials are available in variable quantities and qualities, unnecessary competition can be avoided via the choice of suitable raw materials for a target application. For example, utilisation of cellulose as carbohydrate source for ethanol production (Kabir Kazi et al., 2010) avoids the discussed competition with easier digestible carbohydrates (sugars, starch) deprived from the food supply chain. Also for cellulose use as a biopolymer several different competing markets can be distinguished. It is clear that these applications and markets will be influenced by large volume shifts. The world will have to reckon with the increase of competition and feedstock shortage (land use/biodiversity) (van Dam, de Klerk-Engels, Struik, & Rabbinge, 2005). It is of interest - in the context of sustainable development of the bioeconomy - to categorize the already available and emerging lignocellulosic resources in a matrix structure. When composing such "cellulose resource matrix" attention should be given to the quality aspects as well as to the available quantities and practical possibilities of processing the

  13. Host factors in nidovirus replication

    Wilde, Adriaan Hugo de


    The interplay between nidoviruses and the infected host cell was investigated. Arterivirus RNA-synthesising activity was shown to depend on intact membranes and on a cytosolic host protein which does not cosediment with the RTC. Furthermore, the immunosuppressant drug cyclosporin A (CsA) blocks repl

  14. Host Adaptation of Staphylococcal Leukocidins

    Vrieling, M.


    Staphylococcus aureus is a human and animal pathogen of global importance and has the capacity to cause disease in distinct host populations, using a large arsenal of secreted proteins to evade the host immune response. Amongst the immune evasion proteins of S. aureus, secreted cytotoxins play a pre

  15. Stennis hosts 2010 Special Olympics


    Sarah Johnson, 28, of Gulfport, carries in the Olympic torch to signal the start of the 2010 Area III Special Olympic games at NASA's John C. Stennis Space Center on March 27. Stennis volunteers hosted special needs athletes from across the area for the event. Stennis is an annual host of the games.

  16. Mesoscale Modeling of Impact Compaction of Primitive Solar System Solids

    Davison, Thomas M; Bland, Philip A


    We have developed a method for simulating the mesoscale compaction of early solar system solids in low velocity impact events, using the iSALE shock physics code. Chondrules are represented by nonporous disks, placed within a porous matrix. By simulating impacts into bimodal mixtures over a wide range of parameter space (including the chondrule-to-matrix ratio, the matrix porosity and composition and the impact velocity), we have shown how each of these parameters influences the shock processing of heterogeneous materials. The temperature after shock processing shows a strong dichotomy: matrix temperatures are elevated much higher than the chondrules, which remain largely cold. Chondrules can protect some matrix from shock compaction, with shadow regions in the lee side of chondrules exhibiting higher porosity that elsewhere in the matrix. Using the results from this mesoscale modelling, we show how the $\\varepsilon-\\alpha$ porous compaction model parameters depend on initial bulk porosity. We also show that ...

  17. CN radical hydrogenation from solid H2 reactions, an alternative way of HCN formation in the interstellar medium

    Borget, Fabien; Müller, Sandra; Grote, Dirk; Theulé, Patrice; Vinogradoff, Vassilissa; Chiavassa, Thierry; Sander, Wolfram


    Context. Molecular hydrogen (H2) is the most abundant molecule of the interstellar medium (ISM) in gas phase and it has been assumed to exist in solid state or as coating on grains. Aims: Our goal is to show that solid H2 can act as a hydrogenation agent, reacting with CN radicals to form HCN. Methods: In a H2 matrix, we studied the hydrogenation of the CN radical generated from the vacuum ultraviolet photolysis (VUV-photolysis) of C2N2 at 3.8 K. We modified the wavelengths and the host gas in order to be sure that CN radicals can abstract H from H2 molecules. Results: HCN monomers, dimers, and oligomers have been characterised by Fourier transform infrared spectroscopy (FTIR). H2CN as well as CN radicals have also been clearly observed during the photolysis performed at 3.8 K. Conclusions: H2 is a hydrogenation reagent towards CN radicals producing HCN. This type of reaction should be taken into account for the reactivity at low temperature in contaminated H2 ice macro-particles (CHIMPs), H2 flakes or in the first sublayers of grains where solid H2 has accumulated.

  18. Electrical and Dielectric Properties of Polyaniline and Polyaniline/Montmorillonite Nanocomposite Prepared by Solid Reaction Using Spectroscopy Impedance

    Imene Bekri-Abbes


    Full Text Available The combination of two components with uniform distribution in nanoscale is expected to facilitate wider applications of the material. In this study, polyaniline (PAn and polyaniline/montmorillonite (Mt nanocomposite were prepared by solid reaction using persulfate of ammonium as oxidant. The phase composition and morphology of the nanocomposite were characterized by FTIR, UV-visible spectroscopy, X-ray diffractometer, thermal gravimetric analysis, and scanning electron microscopy. The electrical and dielectric properties were determined using spectroscopy impedance. The analysis of UV-visible and FTIR spectroscopy demonstrated that aniline chloride has been polymerized into PAn in its conducting emeraldine form. Thermogravimetric analysis suggested that PAn chains intercalated in the clay host are more thermally stable than those of free PAn prepared by solid-solid reaction. Electrical measurements were carried out using the complex impedance technique in the frequency range of 10−2 to 104 Hz at different temperatures. The ac conductivity data of different nanocomposites were analyzed as a function of frequency and temperature. It has been found that the incorporation of inorganic clay phase into polyaniline matrix has an effect on the electrical and dielectric properties of the nanomaterial.

  19. Polyethylene imine-metal salt solid electrolyte

    Davis, G. T.; Chiang, C. K.; Takahashi, T.


    This research pertains to the development of new solid battery electrolytes. An object of this invention is to provide polymeric electrolytes using a wider variety of metal salts. These and other objects of this invention are accomplished by providing: (1) a solid polymer electrolyte comprising: a matrix of linear poly(ethylene amine) having the formula (-CH2CH2NH-)n; and (2) a metal salt which is LiI, LiClO4, NaI, NaBr, KI, CsSCN, AgNO3, CuCl1, CoCl2, or Mg(ClO4)2, wherein the salt is dissolved in and distributed throughout the poly(ethylene amine) matrix and from more than zero to 0.10 moles of salt are used per mole of monomer repeat unit, (-CH2CH2NH-).

  20. Matrix string partition function

    Kostov, Ivan K; Kostov, Ivan K.; Vanhove, Pierre


    We evaluate quasiclassically the Ramond partition function of Euclidean D=10 U(N) super Yang-Mills theory reduced to a two-dimensional torus. The result can be interpreted in terms of free strings wrapping the space-time torus, as expected from the point of view of Matrix string theory. We demonstrate that, when extrapolated to the ultraviolet limit (small area of the torus), the quasiclassical expressions reproduce exactly the recently obtained expression for the partition of the completely reduced SYM theory, including the overall numerical factor. This is an evidence that our quasiclassical calculation might be exact.

  1. Matrix vector analysis

    Eisenman, Richard L


    This outstanding text and reference applies matrix ideas to vector methods, using physical ideas to illustrate and motivate mathematical concepts but employing a mathematical continuity of development rather than a physical approach. The author, who taught at the U.S. Air Force Academy, dispenses with the artificial barrier between vectors and matrices--and more generally, between pure and applied mathematics.Motivated examples introduce each idea, with interpretations of physical, algebraic, and geometric contexts, in addition to generalizations to theorems that reflect the essential structur

  2. Random matrix theory

    Deift, Percy


    This book features a unified derivation of the mathematical theory of the three classical types of invariant random matrix ensembles-orthogonal, unitary, and symplectic. The authors follow the approach of Tracy and Widom, but the exposition here contains a substantial amount of additional material, in particular, facts from functional analysis and the theory of Pfaffians. The main result in the book is a proof of universality for orthogonal and symplectic ensembles corresponding to generalized Gaussian type weights following the authors' prior work. New, quantitative error estimates are derive

  3. Supported Molecular Matrix Electrophoresis.

    Matsuno, Yu-Ki; Kameyama, Akihiko


    Mucins are difficult to separate using conventional gel electrophoresis methods such as SDS-PAGE and agarose gel electrophoresis, owing to their large size and heterogeneity. On the other hand, cellulose acetate membrane electrophoresis can separate these molecules, but is not compatible with glycan analysis. Here, we describe a novel membrane electrophoresis technique, termed "supported molecular matrix electrophoresis" (SMME), in which a porous polyvinylidene difluoride (PVDF) membrane filter is used to achieve separation. This description includes the separation, visualization, and glycan analysis of mucins with the SMME technique.

  4. Larval helminths in intermediate hosts

    Fredensborg, Brian Lund; Poulin, R


    a reduction in size, caused by crowding, virtually nothing is known about longer-lasting effects after transmission to the definitive host. This study is the first to use in vitro cultivation with feeding of adult trematodes to investigate how numbers of parasites in the intermediate host affect the size......Density-dependent effects on parasite fitness have been documented from adult helminths in their definitive hosts. There have, however, been no studies on the cost of sharing an intermediate host with other parasites in terms of reduced adult parasite fecundity. Even if larval parasites suffer...... and fecundity of adult parasites. For this purpose, we examined two different infracommunities of parasites in crustacean hosts. Firstly, we used experimental infections of Maritrema novaezealandensis in the amphipod, Paracalliope novizealandiae, to investigate potential density-dependent effects in single...

  5. Salmonellae interactions with host processes.

    LaRock, Doris L; Chaudhary, Anu; Miller, Samuel I


    Salmonellae invasion and intracellular replication within host cells result in a range of diseases, including gastroenteritis, bacteraemia, enteric fever and focal infections. In recent years, considerable progress has been made in our understanding of the molecular mechanisms that salmonellae use to alter host cell physiology; through the delivery of effector proteins with specific activities and through the modulation of defence and stress response pathways. In this Review, we summarize our current knowledge of the complex interplay between bacterial and host factors that leads to inflammation, disease and, in most cases, control of the infection by its animal hosts, with a particular focus on Salmonella enterica subsp. enterica serovar Typhimurium. We also highlight gaps in our knowledge of the contributions of salmonellae and the host to disease pathogenesis, and we suggest future avenues for further study.

  6. Matrix algebra for linear models

    Gruber, Marvin H J


    Matrix methods have evolved from a tool for expressing statistical problems to an indispensable part of the development, understanding, and use of various types of complex statistical analyses. This evolution has made matrix methods a vital part of statistical education. Traditionally, matrix methods are taught in courses on everything from regression analysis to stochastic processes, thus creating a fractured view of the topic. Matrix Algebra for Linear Models offers readers a unique, unified view of matrix analysis theory (where and when necessary), methods, and their applications. Written f

  7. Extracellular Matrix Proteins

    Linda Christian Carrijo-Carvalho


    Full Text Available Lipocalin family members have been implicated in development, regeneration, and pathological processes, but their roles are unclear. Interestingly, these proteins are found abundant in the venom of the Lonomia obliqua caterpillar. Lipocalins are β-barrel proteins, which have three conserved motifs in their amino acid sequence. One of these motifs was shown to be a sequence signature involved in cell modulation. The aim of this study is to investigate the effects of a synthetic peptide comprising the lipocalin sequence motif in fibroblasts. This peptide suppressed caspase 3 activity and upregulated Bcl-2 and Ki-67, but did not interfere with GPCR calcium mobilization. Fibroblast responses also involved increased expression of proinflammatory mediators. Increase of extracellular matrix proteins, such as collagen, fibronectin, and tenascin, was observed. Increase in collagen content was also observed in vivo. Results indicate that modulation effects displayed by lipocalins through this sequence motif involve cell survival, extracellular matrix remodeling, and cytokine signaling. Such effects can be related to the lipocalin roles in disease, development, and tissue repair.

  8. Current Generation in Double-Matrix Structure: A Theoretical Simulation

    Bogdan Lukiyanets; Dariya Matulka; Ivan Grygorchak


    Peculiarities of kinetic characteristics in a supramolecular system, in particular, in a double‐matrix structure observed at change of the guest content in a matrix‐host are investigated. Results obtained within the framework of a time‐independent one‐dimensional Schrödinger equation with three barrier potential qualitatively explain experimental data. They indicate the importance of size quantization of a system, correlation between energy and geometric characteristics of both guest and hos...

  9. Reducing Actinide Production Using Inert Matrix Fuels

    Deinert, Mark [Colorado School of Mines, Golden, CO (United States)


    The environmental and geopolitical problems that surround nuclear power stem largely from the longlived transuranic isotopes of Am, Cm, Np and Pu that are contained in spent nuclear fuel. New methods for transmuting these elements into more benign forms are needed. Current research efforts focus largely on the development of fast burner reactors, because it has been shown that they could dramatically reduce the accumulation of transuranics. However, despite five decades of effort, fast reactors have yet to achieve industrial viability. A critical limitation to this, and other such strategies, is that they require a type of spent fuel reprocessing that can efficiently separate all of the transuranics from the fission products with which they are mixed. Unfortunately, the technology for doing this on an industrial scale is still in development. In this project, we explore a strategy for transmutation that can be deployed using existing, current generation reactors and reprocessing systems. We show that use of an inert matrix fuel to recycle transuranics in a conventional pressurized water reactor could reduce overall production of these materials by an amount that is similar to what is achievable using proposed fast reactor cycles. Furthermore, we show that these transuranic reductions can be achieved even if the fission products are carried into the inert matrix fuel along with the transuranics, bypassing the critical separations hurdle described above. The implications of these findings are significant, because they imply that inert matrix fuel could be made directly from the material streams produced by the commercially available PUREX process. Zirconium dioxide would be an ideal choice of inert matrix in this context because it is known to form a stable solid solution with both fission products and transuranics.

  10. 双重介质非饱和两相流岩体热流固损伤模型研究%Study on Thermal Deterioration Model of Liquid and Solid in Double Porous Medium Rock Matrix with Unsaturated Two-phase Flow

    魏长霖; 齐悦


    以孔隙-裂缝双重孔隙介质为研究对象,建立孔隙度与岩体应变数学模型和温度场诱导应力模型.基于Terzaghi有效应力原理,建立注水开采过程温度-流体-岩石骨架的应力分布模型.考虑注水压力和注水温度场应力导致的岩体孔隙-裂隙的变形、成核和增长,采用应变孔隙度定义损伤变量,建立了以Gurson-Tvergaard-Needleman圆柱体胞模型为塑性屈服函数的双重孔隙介质饱和热流固损伤本构模型.以某1口生产井为研究对象,通过有限元软件数值模拟得到:温度场诱导应力、注水压力诱导应力和岩石应力分布规律;应力与损伤变量、应变孔隙度演化规律.新模型对油田注水开采过程中储层孔隙和裂缝的变化提供了新的研究方法和理论依据.%The double porous medium that is a medium between pore and fracture is selected as an object of study. The inductive stress model of thermal field is built, as well as the mathematical model of porosity and rock matrix strain. Based on the Terzaghi effective stress principle, the stress distribution model is built which is the relationship of temperature, liquid and rock skeleton during period of waterflood exploitation. The processes are considered , which are deformation, nucleation and growing of pore and fracture that are induced by stress of injection pressure and injection temperature field stress. The damage variable is defined by strain porosity. The constitutional equation of double pore medium saturated liquid-solid is set up where the Gurson Tvergaard Needleman cylindric representative volume element ( RVE) is taken as plastic yielding function. Take some well in one oil field, the result is concluded form numerical simulation of finite element software, which are induced stresses of thermal field and waterflood pressure and rock stress distribution rule, together with evolving regulations of stress and damage variable and strain porosity. The new model

  11. Leptospira interrogans endostatin-like outer membrane proteins bind host fibronectin, laminin and regulators of complement.

    Brian Stevenson

    Full Text Available The pathogenic spirochete Leptospira interrogans disseminates throughout its hosts via the bloodstream, then invades and colonizes a variety of host tissues. Infectious leptospires are resistant to killing by their hosts' alternative pathway of complement-mediated killing, and interact with various host extracellular matrix (ECM components. The LenA outer surface protein (formerly called LfhA and Lsa24 was previously shown to bind the host ECM component laminin and the complement regulators factor H and factor H-related protein-1. We now demonstrate that infectious L. interrogans contain five additional paralogs of lenA, which we designated lenB, lenC, lenD, lenE and lenF. All six genes encode domains predicted to bear structural and functional similarities with mammalian endostatins. Sequence analyses of genes from seven infectious L. interrogans serovars indicated development of sequence diversity through recombination and intragenic duplication. LenB was found to bind human factor H, and all of the newly-described Len proteins bound laminin. In addition, LenB, LenC, LenD, LenE and LenF all exhibited affinities for fibronectin, a distinct host extracellular matrix protein. These characteristics suggest that Len proteins together facilitate invasion and colonization of host tissues, and protect against host immune responses during mammalian infection.

  12. Towards host-to-host meeting scheduling negotiation

    Rani Megasari


    Full Text Available This paper presents a different scheme of meeting scheduling negotiation among a large number of personnel in a heterogeneous community. This scheme, named Host-to-Host Negotiation, attempts to produce a stable schedule under uncertain personnel preferences. By collecting information from hosts’ inter organizational meeting, this study intends to guarantee personnel availability. As a consequence, personnel’s and meeting’s profile in this scheme are stored in a centralized manner. This study considers personnel preferences by adapting the Clarke Tax Mechanism, which is categorized as a non manipulated mechanism design. Finally, this paper introduces negotiation strategies based on the conflict handling mode. A host-to-host scheme can give notification if any conflict exist and lead to negotiation process with acceptable disclosed information. Nevertheless, a complete negotiation process will be more elaborated in the future works.

  13. Solid state physics

    Burns, Gerald


    Solid State Physics, International Edition covers the fundamentals and the advanced concepts of solid state physics. The book is comprised of 18 chapters that tackle a specific aspect of solid state physics. Chapters 1 to 3 discuss the symmetry aspects of crystalline solids, while Chapter 4 covers the application of X-rays in solid state science. Chapter 5 deals with the anisotropic character of crystals. Chapters 6 to 8 talk about the five common types of bonding in solids, while Chapters 9 and 10 cover the free electron theory and band theory. Chapters 11 and 12 discuss the effects of moveme

  14. Theoretical solid state physics

    Haug, Albert


    Theoretical Solid State Physics, Volume 1 focuses on the study of solid state physics. The volume first takes a look at the basic concepts and structures of solid state physics, including potential energies of solids, concept and classification of solids, and crystal structure. The book then explains single-electron approximation wherein the methods for calculating energy bands; electron in the field of crystal atoms; laws of motion of the electrons in solids; and electron statistics are discussed. The text describes general forms of solutions and relationships, including collective electron i

  15. Sensing dissolved sediment porewater concentrations of persistent and bioaccumulative poolutants using disposable solid-phase microextraction fibers

    Mayer, P.; Vaes, W.H.J.; Wijnker, F.; Legierse, K.C.H.M.; Kraaij, R.H.; Tolls, J.; Hermens, J.L.M.


    Polymer coated glass fibers were applied as disposable samplers to measure dissolved concentrations of persistent and bioaccumulative pollutants (PBPs) in sediment porewater. The method is called matrix solid-phase microextraction (matrix-SPME), because it utilizes the entire sediment matrix as a re

  16. Host factors influencing viral persistence

    Thomsen, Allan Randrup; Nansen, A; Ørding Andreasen, Susanne


    host were used. Our results reveal that very different outcomes may be observed depending on virus strain and immunocompetence of the host. Thus while CD4+ cells are not critical during the initial phase of virus control, infectious virus reappear in mice lacking CD4+ cells, B cells or CD40 ligand...... that these different outcomes may be explained in relatively simple mathematical terms. This suggests that modelling may be used as a means to predict critical host and virus parameters. Therefore, combining mathematical modelling with precise, quantitative, in vivo analyses looks to be a promising approach...

  17. A critical evaluation of bifidobacterial adhesion to the host tissue

    Christina Westermann


    Full Text Available Bifidobacteria are common inhabitants of the human gastrointestinal tract that, despite a long history of research, have not shown any pathogenic potential whatsoever. By contrast, some bifidobacteria are associated with a number of health-related benefits for the host. The reported beneficial effects of bifidobacteria include competitive exclusion of pathogens, alleviation of symptoms of irritable bowel syndrome and inflammatory bowel disease, and modulation of intestinal and systemic immune responses. Based on these effects, bifidobacteria are widely used as probiotics by pharmaceutical and dairy industries. In order to exert a beneficial effect bifidobacteria have to, at least transiently, colonize the host in a sufficient population size. Besides other criteria such as resistance to manufacturing processes and intestinal transit, potential probiotic bacteria are tested for adhesion to the host structures including intestinal epithelial cells (IECs, mucus and extracellular matrix (ECM components. In the present review article, we summarize the current knowledge on bifidobacterial structures that mediate adhesion to host tissue and compare these to similar structures of pathogenic bacteria. This reveals that most of the adhesive structures and mechanisms involved in adhesion of bifidobacteria to host tissue are similar or even identical to those employed by pathogens to cause disease. It is thus reasonable to assume that these structures and mechanisms are equally important for commensal or probiotic bacteria and play a similar role in the beneficial effects exerted by bifidobacteria.

  18. Modeling supercritical fluid extraction process involving solute-solid interaction

    Goto, M.; Roy, B. Kodama, A.; Hirose, T. [Kumamoto Univ., Kumamoto (Japan)


    Extraction or leaching of solute from natural solid material is a mass transfer process involving dissolution or release of solutes from a solid matrix. Interaction between the solute and solid matrix often influences the supercritical fluid extraction process. A model accounting for the solute-solid interaction as well as mass transfer is developed. The BET equation is used to incorporate the interaction and the solubility of solutes into the local equilibrium in the model. Experimental data for the supercritical extraction of essential oil and cuticular wax from peppermint leaves are successfully analyzed by the model. The effects of parameters on the extraction behavior are demonstrated to illustrate the concept of the model. 18 refs., 5 figs., 1 tab.

  19. Matrix Quantization of Turbulence

    Floratos, Emmanuel


    Based on our recent work on Quantum Nambu Mechanics $\\cite{af2}$, we provide an explicit quantization of the Lorenz chaotic attractor through the introduction of Non-commutative phase space coordinates as Hermitian $ N \\times N $ matrices in $ R^{3}$. For the volume preserving part, they satisfy the commutation relations induced by one of the two Nambu Hamiltonians, the second one generating a unique time evolution. Dissipation is incorporated quantum mechanically in a self-consistent way having the correct classical limit without the introduction of external degrees of freedom. Due to its volume phase space contraction it violates the quantum commutation relations. We demonstrate that the Heisenberg-Nambu evolution equations for the Matrix Lorenz system develop fast decoherence to N independent Lorenz attractors. On the other hand there is a weak dissipation regime, where the quantum mechanical properties of the volume preserving non-dissipative sector survive for long times.

  20. Matrix Graph Grammars

    Velasco, Pedro Pablo Perez


    This book objective is to develop an algebraization of graph grammars. Equivalently, we study graph dynamics. From the point of view of a computer scientist, graph grammars are a natural generalization of Chomsky grammars for which a purely algebraic approach does not exist up to now. A Chomsky (or string) grammar is, roughly speaking, a precise description of a formal language (which in essence is a set of strings). On a more discrete mathematical style, it can be said that graph grammars -- Matrix Graph Grammars in particular -- study dynamics of graphs. Ideally, this algebraization would enforce our understanding of grammars in general, providing new analysis techniques and generalizations of concepts, problems and results known so far.

  1. Matrix anticirculant calculus

    Dimiev, Stancho; Stoev, Peter; Stoilova, Stanislava


    The notion of anticirculant is ordinary of interest for specialists of general algebra (to see for instance [1]). In this paper we develop some aspects of anticirculants in real function theory. Denoting by X≔x0+jx1+⋯+jmxm, xk∈R, m+1 = 2n, and jk is the k-th degree of the matrix j = (0100...00010...00001...0..................-1000...0), we study the functional anticirculants f(X)≔f0(x0,x1,...,xm)+jf1(x0,x1,...,xm)+⋯+jm-1fm-1(x0,x1,...,xm)+jmfm(x0,x1,...,xm), where fk(x0,x1,...,xm) are smooth functions of 2n real variables. A continuation for complex function theory will appear.

  2. Light cone matrix product

    Hastings, Matthew B [Los Alamos National Laboratory


    We show how to combine the light-cone and matrix product algorithms to simulate quantum systems far from equilibrium for long times. For the case of the XXZ spin chain at {Delta} = 0.5, we simulate to a time of {approx} 22.5. While part of the long simulation time is due to the use of the light-cone method, we also describe a modification of the infinite time-evolving bond decimation algorithm with improved numerical stability, and we describe how to incorporate symmetry into this algorithm. While statistical sampling error means that we are not yet able to make a definite statement, the behavior of the simulation at long times indicates the appearance of either 'revivals' in the order parameter as predicted by Hastings and Levitov (e-print arXiv:0806.4283) or of a distinct shoulder in the decay of the order parameter.

  3. Matrix membranes and integrability

    Zachos, C. [Argonne National Lab., IL (United States); Fairlie, D. [University of Durham (United Kingdom). Dept. of Mathematical Sciences; Curtright, T. [University of Miami, Coral Gables, FL (United States). Dept. of Physics


    This is a pedagogical digest of results reported in Curtright, Fairlie, {ampersand} Zachos 1997, and an explicit implementation of Euler`s construction for the solution of the Poisson Bracket dual Nahm equation. But it does not cover 9 and 10-dimensional systems, and subsequent progress on them Fairlie 1997. Cubic interactions are considered in 3 and 7 space dimensions, respectively, for bosonic membranes in Poisson Bracket form. Their symmetries and vacuum configurations are explored. Their associated first order equations are transformed to Nahm`s equations, and are hence seen to be integrable, for the 3-dimensional case, by virtue of the explicit Lax pair provided. Most constructions introduced also apply to matrix commutator or Moyal Bracket analogs.

  4. Mistletoe ecophysiology: Host-parasite interactions

    G. Glatzel; B. W. Geils


    Mistletoes are highly specialized perennial flowering plants adapted to parasitic life on aerial parts of their hosts. In our discussion on the physiological interactions between parasite and host, we focus on water relations, mineral nutrition, and the effect of host vigour. When host photosynthesis is greatest, the xylem water potential of the host is most negative....

  5. Meningococcal interactions with the host.

    Carbonnelle, Etienne; Hill, Darryl J; Morand, Philippe; Griffiths, Natalie J; Bourdoulous, Sandrine; Murillo, Isabel; Nassif, Xavier; Virji, Mumtaz


    Neisseria meningitidis interacts with host tissues through hierarchical, concerted and co-ordinated actions of a number of adhesins; many of which undergo antigenic and phase variation, a strategy that helps immune evasion. Three major structures, pili, Opa and Opc predominantly influence bacterial adhesion to host cells. Pili and Opa proteins also determine host and tissue specificity while Opa and Opc facilitate efficient cellular invasion. Recent studies have also implied a role of certain adhesin-receptor pairs in determining increased host susceptibility to infection. This chapter examines our current knowledge of meningococcal adhesion and invasion mechanisms particularly related to human epithelial and endothelial cells which are of primary importance in the disease process.

  6. Spherical membranes in Matrix theory

    Kabat, D; Kabat, Daniel; Taylor, Washington


    We consider membranes of spherical topology in uncompactified Matrix theory. In general for large membranes Matrix theory reproduces the classical membrane dynamics up to 1/N corrections; for certain simple membrane configurations, the equations of motion agree exactly at finite N. We derive a general formula for the one-loop Matrix potential between two finite-sized objects at large separations. Applied to a graviton interacting with a round spherical membrane, we show that the Matrix potential agrees with the naive supergravity potential for large N, but differs at subleading orders in N. The result is quite general: we prove a pair of theorems showing that for large N, after removing the effects of gravitational radiation, the one-loop potential between classical Matrix configurations agrees with the long-distance potential expected from supergravity. As a spherical membrane shrinks, it eventually becomes a black hole. This provides a natural framework to study Schwarzschild black holes in Matrix theory.

  7. What Are Solid Fats?

    ... fatty acids. Most solid fats are high in saturated fats and/or trans fats and have less monounsaturated ... Animal products containing solid fats also contain cholesterol. Saturated fats and trans fats tend to raise "bad" (LDL) ...

  8. Nonlinear algebraic multigrid for constrained solid mechanics problems using Trilinos

    Gee, M.W.; R. S. Tuminaro


    The application of the finite element method to nonlinear solid mechanics problems results in the neccessity to repeatedly solve a large nonlinear set of equations. In this paper we limit ourself to problems arising in constrained solid mechanics problems. It is common to apply some variant of Newton?s method or a Newton? Krylov method to such problems. Often, an analytic Jacobian matrix is formed and used in the above mentioned methods. However, if no analytic Jacobian is given, Newton metho...

  9. Design and performance of felodipine-based solid dispersions

    Langham, Zoe A.


    In recent years the pharmaceutical industry has seen a rise in the number of drug compounds with low aqueous solubility, and consequently poor oral bioavailablility. One potential solution to this problem is to formulate such compounds as solid dispersions, whereby the drug is dispersed in a carrier matrix in the solid state. In this thesis, the hypothesis that a number of drug-drug and drug-polymer intermolecular interactions influence the physical stability and dissolution performance o...

  10. Linearized supergravity from Matrix theory

    Kabat, D; Kabat, Daniel; Taylor, Washington


    We show that the linearized supergravity potential between two objects arising from the exchange of quanta with zero longitudinal momentum is reproduced to all orders in 1/r by terms in the one-loop Matrix theory potential. The essential ingredient in the proof is the identification of the Matrix theory quantities corresponding to moments of the stress tensor and membrane current. We also point out that finite-N Matrix theory violates the Equivalence Principle.

  11. Lectures on Matrix Field Theory

    Ydri, Badis

    The subject of matrix field theory involves matrix models, noncommutative geometry, fuzzy physics and noncommutative field theory and their interplay. In these lectures, a lot of emphasis is placed on the matrix formulation of noncommutative and fuzzy spaces, and on the non-perturbative treatment of the corresponding field theories. In particular, the phase structure of noncommutative $\\phi^4$ theory is treated in great detail, and an introduction to noncommutative gauge theory is given.

  12. Matrix elements of unstable states

    Bernard, V; Meißner, U -G; Rusetsky, A


    Using the language of non-relativistic effective Lagrangians, we formulate a systematic framework for the calculation of resonance matrix elements in lattice QCD. The generalization of the L\\"uscher-Lellouch formula for these matrix elements is derived. We further discuss in detail the procedure of the analytic continuation of the resonance matrix elements into the complex energy plane and investigate the infinite-volume limit.

  13. Enhancing an R-matrix

    MacKaay, M A


    In order to construct a representation of the tangle category one needs an enhanced R-matrix. In this paper we define a sufficient and necessary condition for enhancement that can be checked easily for any R-matrix. If the R-matrix can be enhanced, we also show how to construct the additional data that define the enhancement. As a direct consequence we find a sufficient condition for the construction of a knot invariant.

  14. Tetraphenylborate Solids Stability Tests

    Walker, D.D. [Westinghouse Savannah River Company, AIKEN, SC (United States)


    Tetraphenylborate solids are a potentially large source of benzene in the slurries produced in the In-Tank Precipitation (ITP) process. The stability of the solids is an important consideration in the safety analysis of the process and we desire an understanding of the factors that influence the rate of conversion of the solids to benzene. This report discusses current testing of the stability of tetraphenylborate solids.

  15. Laser cooling of solids

    Epstein, Richard I [Los Alamos National Laboratory; Sheik-bahae, Mansoor [UNM


    We present an overview of solid-state optical refrigeration also known as laser cooling in solids by fluorescence upconversion. The idea of cooling a solid-state optical material by simply shining a laser beam onto it may sound counter intuitive but is rapidly becoming a promising technology for future cryocooler. We chart the evolution of this science in rare-earth doped solids and semiconductors.

  16. Electron Spin Resonance of Tetrahedral Transition Metal Oxyanions (MO4n-) in Solids.

    Greenblatt, M.


    Outlines general principles in observing sharp electron spin resonance (ESR) lines in the solid state by incorporating the transition metal ion of interest into an isostructural diamagnetic host material in small concentration. Examples of some recent studies are described. (CS)

  17. Matrix Models and Gravitational Corrections

    Dijkgraaf, R; Temurhan, M; Dijkgraaf, Robbert; Sinkovics, Annamaria; Temurhan, Mine


    We provide evidence of the relation between supersymmetric gauge theories and matrix models beyond the planar limit. We compute gravitational R^2 couplings in gauge theories perturbatively, by summing genus one matrix model diagrams. These diagrams give the leading 1/N^2 corrections in the large N limit of the matrix model and can be related to twist field correlators in a collective conformal field theory. In the case of softly broken SU(N) N=2 super Yang-Mills theories, we find that these exact solutions of the matrix models agree with results obtained by topological field theory methods.

  18. A matrix model for WZW

    Dorey, Nick [Department of Applied Mathematics and Theoretical Physics, University of Cambridge,Wilberforce Road, Cambridge, CB3 OWA (United Kingdom); Tong, David [Department of Applied Mathematics and Theoretical Physics, University of Cambridge,Wilberforce Road, Cambridge, CB3 OWA (United Kingdom); Department of Theoretical Physics, TIFR,Homi Bhabha Road, Mumbai 400 005 (India); Stanford Institute for Theoretical Physics,Via Pueblo, Stanford, CA 94305 (United States); Turner, Carl [Department of Applied Mathematics and Theoretical Physics, University of Cambridge,Wilberforce Road, Cambridge, CB3 OWA (United Kingdom)


    We study a U(N) gauged matrix quantum mechanics which, in the large N limit, is closely related to the chiral WZW conformal field theory. This manifests itself in two ways. First, we construct the left-moving Kac-Moody algebra from matrix degrees of freedom. Secondly, we compute the partition function of the matrix model in terms of Schur and Kostka polynomials and show that, in the large N limit, it coincides with the partition function of the WZW model. This same matrix model was recently shown to describe non-Abelian quantum Hall states and the relationship to the WZW model can be understood in this framework.

  19. A Matrix Model for WZW

    Dorey, Nick; Turner, Carl


    We study a U(N) gauged matrix quantum mechanics which, in the large N limit, is closely related to the chiral WZW conformal field theory. This manifests itself in two ways. First, we construct the left-moving Kac-Moody algebra from matrix degrees of freedom. Secondly, we compute the partition function of the matrix model in terms of Schur and Kostka polynomials and show that, in the large $N$ limit, it coincides with the partition function of the WZW model. This same matrix model was recently shown to describe non-Abelian quantum Hall states and the relationship to the WZW model can be understood in this framework.

  20. Solid State Division

    Green, P.H.; Watson, D.M. (eds.)


    This report contains brief discussions on work done in the Solid State Division of Oak Ridge National Laboratory. The topics covered are: Theoretical Solid State Physics; Neutron scattering; Physical properties of materials; The synthesis and characterization of materials; Ion beam and laser processing; and Structure of solids and surfaces. (LSP)

  1. Extended Matrix Variate Hypergeometric Functions and Matrix Variate Distributions

    Daya K. Nagar


    Full Text Available Hypergeometric functions of matrix arguments occur frequently in multivariate statistical analysis. In this paper, we define and study extended forms of Gauss and confluent hypergeometric functions of matrix arguments and show that they occur naturally in statistical distribution theory.

  2. Resolidification of metal matrix composites in microgravity

    Vugt, L. van; Froyen, L. [Leuven Univ., Heverlee (BE). Dept. of Metallurgy and Materials Engineering (MTM)


    During EuroMIR 94 (Altibor) and EuroMIR 95 (Alinsitu) space experiments, the influence of gravity on segregation and clustering of ceramic particles in an aluminium matrix is investigated, in combination with the effect of the thermal gradient and cooling rate. The reinforcements were respectively TiB{sub 2} and SiC. On comparison with the ground processed reference samples it appears that the distribution of the particles in the resolidified material is much more homogeneous, due to sedimentation of the reinforcements. On microscopic scale, differences in particle distribution can be found at a slow and fast cooling. The agglomeration of particles increases with a decreasing of the thermal gradient. In all used systems the particles arranged as a three dimensional skeleton during the liquid state, which interact with the solid-liquid interface during solidification. (orig.)

  3. Matrix Product Operators, Matrix Product States, and ab initio Density Matrix Renormalization Group algorithms

    Chan, Garnet Kin-Lic; Nakatani, Naoki; Li, Zhendong; White, Steven R


    Current descriptions of the ab initio DMRG algorithm use two superficially different languages: an older language of the renormalization group and renormalized operators, and a more recent language of matrix product states and matrix product operators. The same algorithm can appear dramatically different when written in the two different vocabularies. In this work, we carefully describe the translation between the two languages in several contexts. First, we describe how to efficiently implement the ab-initio DMRG sweep using a matrix product operator based code, and the equivalence to the original renormalized operator implementation. Next we describe how to implement the general matrix product operator/matrix product state algebra within a pure renormalized operator-based DMRG code. Finally, we discuss two improvements of the ab initio DMRG sweep algorithm motivated by matrix product operator language: Hamiltonian compression, and a sum over operators representation that allows for perfect computational par...

  4. Load redistribution considerations in the fracture of ceramic matrix composites

    Thomas, David J.; Wetherhold, Robert C.


    Using a macroscopic viewpoint, composite laminae are homogeneous orthotropic solids whose directional strengths are random variables. Incorporation of these random variable strengths into failure models, either interactive or noninteractive, allows for the evaluation of the lamina reliability under a given stress state. Using a noninteractive criterion for demonstration purposes, laminate reliabilities are calculated assuming previously established load sharing rules for the redistribution of load as the failure of laminae occur. The matrix cracking predicted by ACK theory is modeled to allow a loss of stiffness in the fiber direction. The subsequent failure in the fiber direction is controlled by a modified bundle theory. Results are compared with previous models which did not permit separate consideration of matrix cracking, as well as to results obtained from experimental data. The effects of variations from the ideal physical geometry which is normally used to depict the matrix cracking are also studied.

  5. Ceramic matrix composite article and process of fabricating a ceramic matrix composite article

    Cairo, Ronald Robert; DiMascio, Paul Stephen; Parolini, Jason Robert


    A ceramic matrix composite article and a process of fabricating a ceramic matrix composite are disclosed. The ceramic matrix composite article includes a matrix distribution pattern formed by a manifold and ceramic matrix composite plies laid up on the matrix distribution pattern, includes the manifold, or a combination thereof. The manifold includes one or more matrix distribution channels operably connected to a delivery interface, the delivery interface configured for providing matrix material to one or more of the ceramic matrix composite plies. The process includes providing the manifold, forming the matrix distribution pattern by transporting the matrix material through the manifold, and contacting the ceramic matrix composite plies with the matrix material.

  6. Preparation of SiC Fiber Reinforced Nickel Matrix Composite

    Lu Zhang; Nanlin Shi; Jun Gong; Chao Sunt


    A method of preparing continuous(Al+Al2O3)-coated SiC fiber reinforced nickel matrix composite was presented,in which the diffusion between SiC fiber and nickel matrix could be prevented.Magnetron sputtering is used to deposit Ni coating on the surface of the(Al+Al2O3)-coated SiC fiber in preparation of the precursor wires.It is shown that the deposited Ni coating combines well with the(Al+Al2O3) coating and has little negative effect on the tensile strength of(Al+Al2O3)-coated SiC fiber.Solid-state diffusion bonding process is employed to prepare the(Al+Al2O3)-coated SiC fiber reinforced nickel matrix with 37% fibers in volume.The solid-state diffusion bonding process is optimized and the optimum parameters are temperature of 870,pressure of 50 MPa and holding time of 2 h.Under this condition,the precursor wires can diffuse well,composite of full density can be formed and the(Al+Al2O3) coating is effective to restrict the reaction between SiC fiber and nickel matrix.

  7. Solid expellant plasma generator

    Stone, Nobie H. (Inventor); Poe, Garrett D. (Inventor); Rood, Robert (Inventor)


    An improved solid expellant plasma generator has been developed. The plasma generator includes a support housing, an electrode rod located in the central portion of the housing, and a mass of solid expellant material that surrounds the electrode rod within the support housing. The electrode rod and the solid expellant material are made of separate materials that are selected so that the electrode and the solid expellant material decompose at the same rate when the plasma generator is ignited. This maintains a point of discharge of the plasma at the interface between the electrode and the solid expellant material.

  8. Solid state phenomena

    Lawrance, R


    Solid State Phenomena explores the fundamentals of the structure and their influence on the properties of solids. This book is composed of five chapters that focus on the electrical and thermal conductivities of crystalline solids. Chapter 1 describes the nature of solids, particularly metals and crystalline materials. This chapter also presents a model to evaluate crystal structure, the forces between atom pairs, and the mechanism of plastic and elastic deformation. Chapter 2 demonstrates random vibrations of atoms in a solid using a one-dimensional array, while Chapter 3 examines the resista


    Qiu Jinghui


    The author gives a dual characterization of solid cones in locally convex spaces.From this the author obtains some criteria for judging convex cones to be solid in various inds of locally convex spaces. Using a general expression of the interior of a solid cone,the author obtains a number of necessary and sufficient conditions for convex cones to be solid in the framework of Banach spaces. In particular, the author gives a dual relationship between solid cones and generalized sharp cones. The related known results are improved and extended.

  10. Solids fluidizer-injector

    Bulicz, T.R.


    An apparatus and process are described for fluidizing solid particles by causing rotary motion of the solid particles in a fluidizing chamber by a plurality of rotating projections extending from a rotatable cylinder end wall interacting with a plurality of fixed projections extending from an opposite fixed end wall and passing the solid particles through a radial feed orifice open to the solids fluidizing chamber on one side and a solid particle utilization device on the other side. The apparatus and process are particularly suited for obtaining intermittent feeding with continual solids supply to the fluidizing chamber. The apparatus and process are suitable for injecting solid particles, such as coal, to an internal combustion engine. 3 figs.

  11. Solid Base Catalysis

    Ono, Yoshio


    The importance of solid base catalysts has come to be recognized for their environmentally benign qualities, and much significant progress has been made over the past two decades in catalytic materials and solid base-catalyzed reactions. The book is focused on the solid base. Because of the advantages over liquid bases, the use of solid base catalysts in organic synthesis is expanding. Solid bases are easier to dispose than liquid bases, separation and recovery of products, catalysts and solvents are less difficult, and they are non-corrosive. Furthermore, base-catalyzed reactions can be performed without using solvents and even in the gas phase, opening up more possibilities for discovering novel reaction systems. Using numerous examples, the present volume describes the remarkable role solid base catalysis can play, given the ever increasing worldwide importance of "green" chemistry. The reader will obtain an overall view of solid base catalysis and gain insight into the versatility of the reactions to whic...

  12. Photochemistry of the ozone-water complex in cryogenic neon, argon, and krypton matrixes.

    Tsuge, Masashi; Tsuji, Kazuhide; Kawai, Akio; Shibuya, Kazuhiko


    The photochemistry of ozone-water complexes and the wavelength dependence of the reactions were studied by matrix isolation FTIR spectrometry in neon, argon, and krypton matrixes. Hydrogen peroxide was formed upon the irradiation of UV light below 355 nm. Quantitative analyses of the reactant and product were performed to evaluate the matrix cage effect of the photoreaction. In argon and krypton matrixes, a bimolecular O((1)D) + H2O → H2O2 reaction was found to occur to form hydrogen peroxide, where the O((1)D) atom generated by the photolysis of ozone diffused in the cryogenic solids to encounter water. In a neon matrix, hydrogen peroxide was generated through intracage photoreaction of the ozone-water complex, indicating that a neon matrix medium is most appropriate to study the photochemistry of the ozone-water complex.

  13. Matrix Theory of pp Waves

    Michelson, J


    The Matrix Theory that has been proposed for various pp wave backgrounds is discussed. Particular emphasis is on the existence of novel nontrivial supersymmetric solutions of the Matrix Theory. These correspond to branes of various shapes (ellipsoidal, paraboloidal, and possibly hyperboloidal) that are unexpected from previous studies of branes in pp wave geometries.

  14. How to Study a Matrix

    Jairam, Dharmananda; Kiewra, Kenneth A.; Kauffman, Douglas F.; Zhao, Ruomeng


    This study investigated how best to study a matrix. Fifty-three participants studied a matrix topically (1 column at a time), categorically (1 row at a time), or in a unified way (all at once). Results revealed that categorical and unified study produced higher: (a) performance on relationship and fact tests, (b) study material satisfaction, and…

  15. Machining of Metal Matrix Composites


    Machining of Metal Matrix Composites provides the fundamentals and recent advances in the study of machining of metal matrix composites (MMCs). Each chapter is written by an international expert in this important field of research. Machining of Metal Matrix Composites gives the reader information on machining of MMCs with a special emphasis on aluminium matrix composites. Chapter 1 provides the mechanics and modelling of chip formation for traditional machining processes. Chapter 2 is dedicated to surface integrity when machining MMCs. Chapter 3 describes the machinability aspects of MMCs. Chapter 4 contains information on traditional machining processes and Chapter 5 is dedicated to the grinding of MMCs. Chapter 6 describes the dry cutting of MMCs with SiC particulate reinforcement. Finally, Chapter 7 is dedicated to computational methods and optimization in the machining of MMCs. Machining of Metal Matrix Composites can serve as a useful reference for academics, manufacturing and materials researchers, manu...

  16. Matrix Model Approach to Cosmology

    Chaney, A; Stern, A


    We perform a systematic search for rotationally invariant cosmological solutions to matrix models, or more specifically the bosonic sector of Lorentzian IKKT-type matrix models, in dimensions $d$ less than ten, specifically $d=3$ and $d=5$. After taking a continuum (or commutative) limit they yield $d-1$ dimensional space-time surfaces, with an attached Poisson structure, which can be associated with closed, open or static cosmologies. For $d=3$, we obtain recursion relations from which it is possible to generate rotationally invariant matrix solutions which yield open universes in the continuum limit. Specific examples of matrix solutions have also been found which are associated with closed and static two-dimensional space-times in the continuum limit. The solutions provide for a matrix resolution of cosmological singularities. The commutative limit reveals other desirable features, such as a solution describing a smooth transition from an initial inflation to a noninflationary era. Many of the $d=3$ soluti...

  17. Matrix convolution operators on groups

    Chu, Cho-Ho


    In the last decade, convolution operators of matrix functions have received unusual attention due to their diverse applications. This monograph presents some new developments in the spectral theory of these operators. The setting is the Lp spaces of matrix-valued functions on locally compact groups. The focus is on the spectra and eigenspaces of convolution operators on these spaces, defined by matrix-valued measures. Among various spectral results, the L2-spectrum of such an operator is completely determined and as an application, the spectrum of a discrete Laplacian on a homogeneous graph is computed using this result. The contractivity properties of matrix convolution semigroups are studied and applications to harmonic functions on Lie groups and Riemannian symmetric spaces are discussed. An interesting feature is the presence of Jordan algebraic structures in matrix-harmonic functions.

  18. Selected Topics on Mass Transport in Gas-solid Interactions

    Somers, Marcel A.J.


    The present article is a short review containing examples of the role of mass transport in the solid state during gas-solid interactions. Examples are taken from the authors' research on the interaction of carbon and/or nitrogen with iron-based metals. Topics dealt with are diffusion......-controlled dissolution of carbon in an austenite matrix, nucleation of nitrides at an iron surface, the competition between surface reaction and solid state diffusion during iron-nitride layer growth and the evolution of the morphology of a carbonitride layer during nitrocarburizing. The work presented focuses...

  19. Targeting a single mismatched minor histocompatibility antigen with tumor-restricted expression eradicates human solid tumors

    L. Hambaeh (Lothar); M. Vermeij (Marcel); A. Buser (Andreas); Z. Aghai (Zohara); Th.H. van der Kwast (Theo); E. Goulmy (Els)


    textabstractRegressions of metastatic solid tumors after allogeneic human leukocyte antigen (HLA)-matched stem cell transplantation (SCT) are often associated with detrimental graft-versus-host disease (GVHD). The graft-versus-host reaction of the HLA-matched donor is directed mainly against the mul

  20. Interactions between Trypanosoma cruzi Secreted Proteins and Host Cell Signaling Pathways

    Watanabe Costa, Renata; da Silveira, Jose F.; Bahia, Diana


    Chagas disease is one of the prevalent neglected tropical diseases, affecting at least 6–7 million individuals in Latin America. It is caused by the protozoan parasite Trypanosoma cruzi, which is transmitted to vertebrate hosts by blood-sucking insects. After infection, the parasite invades and multiplies in the myocardium, leading to acute myocarditis that kills around 5% of untreated individuals. T. cruzi secretes proteins that manipulate multiple host cell signaling pathways to promote host cell invasion. The primary secreted lysosomal peptidase in T. cruzi is cruzipain, which has been shown to modulate the host immune response. Cruzipain hinders macrophage activation during the early stages of infection by interrupting the NF-kB P65 mediated signaling pathway. This allows the parasite to survive and replicate, and may contribute to the spread of infection in acute Chagas disease. Another secreted protein P21, which is expressed in all of the developmental stages of T. cruzi, has been shown to modulate host phagocytosis signaling pathways. The parasite also secretes soluble factors that exert effects on host extracellular matrix, such as proteolytic degradation of collagens. Finally, secreted phospholipase A from T. cruzi contributes to lipid modifications on host cells and concomitantly activates the PKC signaling pathway. Here, we present a brief review of the interaction between secreted proteins from T. cruzi and the host cells, emphasizing the manipulation of host signaling pathways during invasion. PMID:27065960

  1. Interactions between Trypanosoma cruzi secreted proteins and host cell signaling pathways

    Renata Watanabe Costa


    Full Text Available Chagas disease is one of the prevalent neglected tropical diseases, affecting at least 6-7 million individuals in Latin America. It is caused by the protozoan parasite Trypanosoma cruzi (T. cruzi, which is transmitted to vertebrate hosts by blood-sucking insects. After infection, the parasite invades and multiplies in the myocardium, leading to acute myocarditis that kills around 5% of untreated individuals. T. cruzi secretes proteins that manipulate multiple host cell signaling pathways to promote host cell invasion. The primary secreted lysosomal peptidase in T. cruzi is cruzipain, which has been shown to modulate the host immune response. Cruzipain hinders macrophage activation during the early stages of infection by interrupting the NF-kB P65 mediated signaling pathway. This allows the parasite to survive and replicate, and may contribute to the spread of infection in acute Chagas disease. Another secreted protein P21, which is expressed in all of the developmental stages of T. cruzi, has been shown to modulate host phagocytosis signaling pathways. The parasite also secretes soluble factors that exert effects on host extracellular matrix, such as proteolytic degradation of collagens. Finally, secreted phospholipase A from T. cruzi contributes to lipid modifications on host cells and concomitantly activates the PKC signaling pathway. Here we present a brief review of the interaction between secreted proteins from T. cruzi and the host cells, emphasizing the manipulation of host signaling pathways during invasion.

  2. Dissection of the host-pathogen interaction in human tuberculosis using a bioengineered 3-dimensional model

    Tezera, Liku B; Bielecka, Magdalena K; Chancellor, Andrew; Reichmann, Michaela T; Shammari, Basim Al; Brace, Patience; Batty, Alex; Tocheva, Annie; Jogai, Sanjay; Marshall, Ben G; Tebruegge, Marc; Jayasinghe, Suwan N; Mansour, Salah; Elkington, Paul T


    Cell biology differs between traditional cell culture and 3-dimensional (3-D) systems, and is modulated by the extracellular matrix. Experimentation in 3-D presents challenges, especially with virulent pathogens. Mycobacterium tuberculosis (Mtb) kills more humans than any other infection and is characterised by a spatially organised immune response and extracellular matrix remodelling. We developed a 3-D system incorporating virulent mycobacteria, primary human blood mononuclear cells and collagen–alginate matrix to dissect the host-pathogen interaction. Infection in 3-D led to greater cellular survival and permitted longitudinal analysis over 21 days. Key features of human tuberculosis develop, and extracellular matrix integrity favours the host over the pathogen. We optimised multiparameter readouts to study emerging therapeutic interventions: cytokine supplementation, host-directed therapy and immunoaugmentation. Each intervention modulates the host-pathogen interaction, but has both beneficial and harmful effects. This methodology has wide applicability to investigate infectious, inflammatory and neoplastic diseases and develop novel drug regimes and vaccination approaches. DOI: PMID:28063256

  3. Host-related factors explaining interindividual variability of carotenoid bioavailability and tissue concentrations in humans

    Bohn, Torsten; Desmarchelier, Charles; Dragsted, Lars O.; Nielsen, Charlotte S.; Stahl, Wilhelm; Rühl, Ralph; Keijer, Jaap; Borel, Patrick


    Carotenoid dietary intake and their endogenous levels have been associated with a decreased risk of several chronic diseases. There are indications that carotenoid bioavailability depends, in addition to the food matrix, on host factors. These include diseases (e.g. colitis), life-style habits (e

  4. The Smallest AGN Host Galaxies

    Greene, J E; Ho, L C


    We describe our efforts to study dwarf galaxies with active nuclei, whose black holes, with masses < 10^6 M_sun, provide the best current observational constraints on the mass distribution of primordial seed black holes. Although these low-mass galaxies do not necessarily contain classical bulges, Barth, Greene, & Ho (2005) show that their stellar velocity dispersions and black hole masses obey the same relation as more massive systems. In order to characterize the properties of the dwarf hosts without the glare of the active nucleus, we have compiled a complementary sample of narrow-line active galaxies with low-mass hosts. The host galaxy properties, both their structures and stellar populations, are consistent with the general properties of low-mass, blue galaxies from Sloan. The black holes in these galaxies are probably radiating close to their Eddington limits, suggesting we may have found Type 2 analogues of narrow-line Seyfert 1 galaxies.

  5. Asteroseismology of Exoplanet Host Stars

    Huber, Daniel


    Asteroseismology is among the most powerful observational tools to determine fundamental properties of stars. Space-based photometry has recently enabled the systematic detection of oscillations in exoplanet host stars, allowing a combination of asteroseismology with transit and radial-velocity measurements to characterize planetary systems. In this contribution I will review the key synergies between asteroseismology and exoplanet science such as the precise determination of radii and ages of exoplanet host stars, as well as applications of asteroseismology to measure spin-orbit inclinations in multiplanet systems and orbital eccentricities of small planets. Finally I will give a brief outlook on asteroseismic studies of exoplanet hosts with current and future space-based missions such as K2 and TESS.

  6. Formation of solid Kr nanoclusters in MgO

    van Huis, MA; van Veen, A; Schut, H; Kooi, BJ; De Hosson, JTM


    The phenomenon of positron confinement enables us to investigate the electronic structure of nanoclusters embedded in host matrices. Solid Kr nanoclusters are a very interesting subject of investigation because of the very low predicted value of the positron affinity of bulk Kr. In this work,

  7. The Inflammasome in Host Defense

    Gang Chen


    Full Text Available Nod-like receptors have emerged as an important family of sensors in host defense. These receptors are expressed in macrophages, dendritic cells and monocytes and play an important role in microbial immunity. Some Nod-like receptors form the inflammasome, a protein complex that activates caspase-1 in response to several stimuli. Caspase-1 activation leads to processing and secretion of pro-inflammatory cytokines such as interleukin (IL-1β and IL-18. Here, we discuss recent advances in the inflammasome field with an emphasis on host defense. We also compare differential requirements for inflammasome activation in dendritic cells, macrophages and monocytes.

  8. Solid state physics advances in research and applications

    Ehrenreich, Henry


    The latest volume in the world renowned Solid State Physics series marks the fruition of Founding Editor David Turnbull''s outstanding tenure as series editor. Volume 47 presents five articles written by leadingexperts on areas including crystal-melt interfacial tension, order-disorder transformation in alloys, brittle matrix composites, surfaces and interfaces, and magnetoresistance.

  9. Propagating Instabilities in Solids

    Kyriakides, Stelios


    Instability is one of the factors which limit the extent to which solids can be loaded or deformed and plays a pivotal role in the design of many structures. Such instabilities often result in localized deformation which precipitates catastrophic failure. Some materials have the capacity to recover their stiffness following a certain amount of localized deformation. This local recovery in stiffness arrests further local deformation and spreading of the instability to neighboring material becomes preferred. Under displacement controlled loading the propagation of the transition fronts can be achieved in a steady-state manner at a constant stress level known as the propagation stress. The stresses in the transition fronts joining the highly deformed zone to the intact material overcome the instability nucleation stresses and, as a result, the propagation stress is usually much lower than the stress required to nucleate the instability. The classical example of this class of material instabilities is L/"uders bands which tend to affect mild steels and other metals. Recent work has demonstrated that propagating instabilities occur in several other materials. Experimental and analytical results from four examples will be used to illustrate this point: First the evolution of L=FCders bands in mild steel strips will be revisited. The second example involves the evolution of stress induced phase transformations (austenite to martensite phases and the reverse) in a shape memory alloy under displacement controlled stretching. The third example is the crushing behavior of cellular materials such as honeycombs and foams made from metals and polymers. The fourth example involves the axial broadening/propagation of kink bands in aligned fiber/matrix composites under compression. The microstructure and, as a result, the micromechanisms governing the onset, localization, local arrest and propagation of instabilities in each of the four materials are vastly different. Despite this

  10. Compensation for risks: host community benefits in siting locally unwanted facilities

    Himmelberger, Jeffery J.; Ratick, Samuel J.; White, Allen L.


    This article analyzes the recent negotiations connected with siting 24 solid-waste landfills in Wisconsin. We examine the association between the type and amount of compensation paid to host communities by facility developers and the size of facilities, certain facility characteristics, the timing of negotiated agreements, the size of the host community, and the socioeconomic status of the host area. Our findings suggest that the level of compensation after adjusting for landfill capacity is positively associated with the percentage of total facility capacity dedicated to host community use, positively associated with the percentage of people of the host area who are in poverty, and larger for public facilities that accept municipal wastes. Other explanatory variables we examined, whose association with levels of compensation proved statistically insignificant, were facility size, facility status (new vs expansion), facility use (countyonly vs multicounty), timing of negotiation, host community size, and the host area education level, population density, and per capita income. We discuss the policy implications of our principal findings and future research questions in light of the persistent opposition surrounding the siting of solid-waste and other waste-management facilities.

  11. Supramolecular chiral host-guest nanoarchitecture induced by the selective assembly of barbituric acid derivative enantiomers

    Sun, Xiaonan; Silly, Fabien; Maurel, Francois; Dong, Changzhi


    Barbituric acid derivatives are prochiral molecules, i.e. they are chiral upon adsorption on surfaces. Scanning tunneling microscopy reveals that barbituric acid derivatives self-assemble into a chiral guest-host supramolecular architecture at the solid-liquid interface on graphite. The host nanoarchitecture has a sophisticated wavy shape pattern and paired guest molecules are nested insides the cavities of the host structure. Each unit cell of the host structure is composed of both enantiomers with a ratio of 1:1. Furthermore, the wavy patterns of the nanoarchitecture are formed from alternative appearance of left- and right-handed chiral building blocks, which makes the network heterochiral. The functional guest-host nanoarchitecture is the result of two-dimensional chiral amplification from single enantiomers to organizational heterochiral supramolecular self-assembly.

  12. Reconstruction of rabbit urethra using urethral extracellular matrix

    杨嗣星; 姚颐; 胡云飞; 宋超; 王玲珑; 金化民


    Background Urethral reconstruction for both congenital and acquired etiologies remains a challenge for most urologic surgeons. Tissue engineering has been proposed as a strategy for urethral reconstruction. The purpose of This study was to determine whether a naturally derived extracellular matrix substitute developed for urethral reconstruction would be suitable for urethral repair in an animal model.Methods A urethral segmental defect was created in 20 male rabbits. The urethral extracellular matrix, obtained and processed from rabbit urethral tissue, was trimmed and transplanted to repair the urethral defect. Then, the regenerated segment was studied histologically by haematoxylin-eosin staining and Van Gieson staining at 10 days, 3 weeks, 6 weeks, and 24 weeks postoperation. Retrograde urethrography was used to evaluate the function of the regenerated urethras of 4 rabbits 10 and 24 weeks after the operation. The urodynamics of 4 rabbits from the experimental group and control group Ⅰ were assessed and compared. In addition, 4 experimental group rabbits were examined by a urethroscope 24 weeks after the operation.Results At 10 days after operation, epithelial cells had migrated from each side, and small vessels were observed in the extracellular matrix. The matrix and adjacent areas of the host tissue were infiltrated with inflammatory cells. The epithelium covered the extracellular matrix fully at 3 weeks postoperation. Well-formed smooth-muscle cells were first confirmed after 6 weeks, at which point the inflammatory cells had disappeared. At 24 weeks postoperation, the regenerated tissue was equivalent to the normal urethra. Urethrography and urodynamic evaluations showed that there was no difference between normal tissue and regenerated tissue.Conclusions Urethral extracellular matrix appears to be a useful material for urethral repair in rabbits. The matrix can be processed easily and has good characteristics for tissue handling and urethral function.

  13. Evaluation of lymphangiogenesis in acellular dermal matrix

    Mario Cherubino


    Full Text Available Introduction: Much attention has been directed towards understanding the phenomena of angiogenesis and lymphangiogenesis in wound healing. Thanks to the manifold dermal substitute available nowadays, wound treatment has improved greatly. Many studies have been published about angiogenesis and cell invasion in INTEGRA® . On the other hand, the development of the lymphatic network in acellular dermal matrix (ADM is a more obscure matter. In this article, we aim to characterize the different phases of host cell invasion in ADM. Special attention was given to lymphangiogenic aspects. Materials and Methods: Among 57 rats selected to analyse the role of ADM in lymphangiogenesis, we created four groups. We performed an excision procedure on both thighs of these rats: On the left one we did not perform any action except repairing the borders of the wound; while on the right one we used INTEGRA® implant. The excision biopsy was performed at four different times: First group after 7 days, second after 14 days, third after 21 days and fourth after 28 days. For our microscopic evaluation, we used the classical staining technique of haematoxylin and eosin and a semi-quantitative method in order to evaluate cellularity counts. To assess angiogenesis and lymphangiogenesis development we employed PROX-1 Ab and CD31/PECAM for immunohistochemical analysis. Results: We found remarkable wound contraction in defects that healed by secondary intention while minor wound contraction was observed in defects treated with ADM. At day 7, optical microscopy revealed a more plentiful cellularity in the granulation tissue compared with the dermal regeneration matrix. The immunohistochemical process highlighted vascular and lymphatic cells in both groups. After 14 days a high grade of fibrosis was noticeable in the non-treated group. At day 21, both lymphatic and vascular endothelial cells were better developed in the group with a dermal matrix application. At day 28

  14. Rheological and solid-state NMR assessments of copovidone/clotrimazole model solid dispersions.

    Yang, Fengyuan; Su, Yongchao; Zhu, Lei; Brown, Chad D; Rosen, Lawrence A; Rosenberg, Kenneth J


    This study aims to assess several model solid dispersions by using dynamic oscillatory rheology, solid-state NMR and other solid phase characterization techniques, and correlate their viscoelastic responses with processing methods and microstructures. A model active pharmaceutical ingredient (API), clotrimazole, was compounded with copovidone to form solid dispersions via various techniques with different mixing capabilities. Physicochemical characterizations of the resulting solid dispersions demonstrated that simple physical mixing led to a poorly mixed blend manifested by existence of large API crystalline content and heterogeneous distribution. Cryogenic milling significantly improved mixing of two components as a result of reduced particle size and increased contact surface area, but produced limited amorphous content. In contrast, hot melt extrusion (HME) processing resulted in a homogenous amorphous solid dispersion because of its inherent mixing efficiency. Storage modulus and viscosities versus frequency of different solid dispersions indicated that the incorporation of API into the polymer matrix resulted in a plasticizing effect which reduced the viscosity. The crystalline/aggregated forms of API also exhibited more elastic response than its amorphous/dispersed counterpart. Temperature ramps of the physical mixture with high API concentration captured a critical temperature, at which a bump was observed in damping factor. This bump was attributed to the dissolution of crystalline API into the polymer. In addition, heating-cooling cycles of various solid dispersions suggested that cryomilling and HME processing could form a homogeneous solid dispersion at low API content, whereas high drug concentration led to a relatively unstable dispersion due to supersaturation of API in the polymer.

  15. Manufacturing Titanium Metal Matrix Composites by Consolidating Matrix Coated Fibres

    Hua-Xin PENG


    Titanium metal matrix composites (TiMMCs) reinforced by continuous silicon carbide fibres are being developed for aerospace applications. TiMMCs manufactured by the consolidation of matrix-coated fibre (MCF) method offer optimum properties because of the resulting uniform fibre distribution, minimum fibre damage and fibre volume fraction control. In this paper, the consolidation of Ti-6Al-4V matrix-coated SiC fibres during vacuum hot pressing has been investigated. Experiments were carried out on multi-ply MCFs under vacuum hot pressing (VHP). In contrast to most of existing studies, the fibre arrangement has been carefully controlled either in square or hexagonal arraysthroughout the consolidated sample. This has enabled the dynamic consolidation behaviour of MCFs to be demonstrated by eliminating the fibre re-arrangement during the VHP process. The microstructural evolution of the matrix coating was reported and the deformation mechanisms involved were discussed.

  16. Plant cell proliferation inside an inorganic host.

    Perullini, Mercedes; Rivero, María Mercedes; Jobbágy, Matías; Mentaberry, Alejandro; Bilmes, Sara A


    In recent years, much attention has been paid to plant cell culture as a tool for the production of secondary metabolites and the expression of recombinant proteins. Plant cell immobilization offers many advantages for biotechnological processes. However, the most extended matrices employed, such as calcium-alginate, cannot fully protect entrapped cells. Sol-gel chemistry of silicates has emerged as an outstanding strategy to obtain biomaterials in which living cells are truly protected. This field of research is rapidly developing and a large number of bacteria and yeast-entrapping ceramics have already been designed for different applications. But even mild thermal and chemical conditions employed in sol-gel synthesis may result harmful to cells of higher organisms. Here we present a method for the immobilization of plant cells that allows cell growth at cavities created inside a silica matrix. Plant cell proliferation was monitored for a 6-month period, at the end of which plant calli of more than 1 mm in diameter were observed inside the inorganic host. The resulting hybrid device had good mechanical stability and proved to be an effective barrier against biological contamination, suggesting that it could be employed for long-term plant cell entrapment applications.

  17. Porous Silicon—A Versatile Host Material

    Klemens Rumpf


    Full Text Available This work reviews the use of porous silicon (PS as a nanomaterial which is extensively investigated and utilized for various applications, e.g., in the fields of optics, sensor technology and biomedicine. Furthermore the combination of PS with one or more materials which are also nanostructured due to their deposition within the porous matrix is discussed. Such nanocompounds offer a broad avenue of new and interesting properties depending on the kind of involved materials as well as on their morphology. The filling of the pores performed by electroless or electrochemical deposition is described, whereas different morphologies, reaching from micro- to macro pores are utilized as host material which can be self-organized or fabricated by prestructuring. For metal-deposition within the porous structures, both ferromagnetic and non-magnetic metals are used. Emphasis will be put on self-arranged mesoporous silicon, offering a quasi-regular pore arrangement, employed as template for filling with ferromagnetic metals. By varying the deposition parameters the precipitation of the metal structures within the pores can be tuned in geometry and spatial distribution leading to samples with desired magnetic properties. The correlation between morphology and magnetic behaviour of such semiconducting/magnetic systems will be determined. Porous silicon and its combination with a variety of filling materials leads to nanocomposites with specific physical properties caused by the nanometric size and give rise to a multiplicity of potential applications in spintronics, magnetic and magneto-optic devices, nutritional food additives as well as drug delivery.

  18. Combining Phylogenetic and Occurrence Information for Risk Assessment of Pest and Pathogen Interactions with Host Plants

    Ángel L. Robles-Fernández


    Full Text Available Phytosanitary agencies conduct plant biosecurity activities, including early detection of potential introduction pathways, to improve control and eradication of pest and pathogen incursions. For such actions, analytical tools based on solid scientific knowledge regarding plant-pest or pathogen relationships for pest risk assessment are needed. Recent evidence indicating that closely related species share a higher chance of becoming infected or attacked by pests has allowed the identification of taxa with different degrees of vulnerability. Here, we use information readily available online about pest-host interactions and their geographic distributions, in combination with host phylogenetic reconstructions, to estimate a pest-host interaction (in some cases infection index in geographic space as a more comprehensive, spatially explicit tool for risk assessment. We demonstrate this protocol using phylogenetic relationships for 20 beetle species and 235 host plant genera: first, we estimate the probability of a host sharing pests, and second, we project the index in geographic space. Overall, the predictions allow identification of the pest-host interaction type (e.g., generalist or specialist, which is largely determined by both host range and phylogenetic constraints. Furthermore, the results can be valuable in terms of identifying hotspots where pests and vulnerable hosts interact. This knowledge is useful for anticipating biological invasions or spreading of disease. We suggest that our understanding of biotic interactions will improve after combining information from multiple dimensions of biodiversity at multiple scales (e.g., phylogenetic signal and host-vector-pathogen geographic distribution.

  19. New pole placement algorithm - Polynomial matrix approach

    Shafai, B.; Keel, L. H.


    A simple and direct pole-placement algorithm is introduced for dynamical systems having a block companion matrix A. The algorithm utilizes well-established properties of matrix polynomials. Pole placement is achieved by appropriately assigning coefficient matrices of the corresponding matrix polynomial. This involves only matrix additions and multiplications without requiring matrix inversion. A numerical example is given for the purpose of illustration.

  20. High temperature polymer matrix composites

    Serafini, Tito T. (Editor)


    These are the proceedings of the High Temperature Polymer Matrix Composites Conference held at the NASA Lewis Research Center on March 16 to 18, 1983. The purpose of the conference is to provide scientists and engineers working in the field of high temperature polymer matrix composites an opportunity to review, exchange, and assess the latest developments in this rapidly expanding area of materials technology. Technical papers are presented in the following areas: (1) matrix development; (2) adhesive development; (3) Characterization; (4) environmental effects; and (5) applications.

  1. Matrix Elements for Hylleraas CI

    Harris, Frank E.

    The limitation to at most a single interelectron distance in individual configurations of a Hylleraas-type multiconfiguration wave function restricts significantly the types of integrals occurring in matrix elements for energy calculations, but even then if the formulation is not handled efficiently the angular parts of these integrals escalate to create expressions of great complexity. This presentation reviews ways in which the angular-momentum calculus can be employed to systematize and simplify the matrix element formulas, particularly those for the kinetic-energy matrix elements.

  2. Investigation of Utilizing a Secant Stiffness Matrix for 2D Nonlinear Shape Optimization and Sensitivity Analysis

    Asghar Vatani Oskouie


    Full Text Available In this article the general non-symmetric parametric form of the incremental secant stiffness matrix for nonlinear analysis of solids have been investigated to present a semi analytical sensitivity analysis approach for geometric nonlinear shape optimization. To approach this aim the analytical formulas of secant stiffness matrix are presented. The models were validated and used to perform investigating different parameters affecting the shape optimization. Numerical examples utilized for this investigating sensitivity analysis with detailed discussions presented.

  3. Solid state video cameras

    Cristol, Y


    Solid State Video Cameras reviews the state of the art in the field of solid-state television cameras as compiled from patent literature. Organized into 10 chapters, the book begins with the basic array types of solid-state imagers and appropriate read-out circuits and methods. Documents relating to improvement of picture quality, such as spurious signal suppression, uniformity correction, or resolution enhancement, are also cited. The last part considerssolid-state color cameras.

  4. Solid propellant rocket motor

    Dowler, W. L.; Shafer, J. I.; Behm, J. W.; Strand, L. D. (Inventor)


    The characteristics of a solid propellant rocket engine with a controlled rate of thrust buildup to a desired thrust level are discussed. The engine uses a regressive burning controlled flow solid propellant igniter and a progressive burning main solid propellant charge. The igniter is capable of operating in a vacuum and sustains the burning of the propellant below its normal combustion limit until the burning propellant surface and combustion chamber pressure have increased sufficiently to provide a stable chamber pressure.

  5. Visual mimicry of host nestlings by cuckoos

    Langmore, Naomi E.; Stevens, Martin; Maurer, Golo; Heinsohn, Robert; Hall, Michelle L.; Peters, Anne; Kilner, Rebecca M.


    Coevolution between antagonistic species has produced instances of exquisite mimicry. Among brood-parasitic cuckoos, host defences have driven the evolution of mimetic eggs, but the evolutionary arms race was believed to be constrained from progressing to the chick stage, with cuckoo nestlings generally looking unlike host young. However, recent studies on bronze-cuckoos have confounded theoretical expectations by demonstrating cuckoo nestling rejection by hosts. Coevolutionary theory predicts reciprocal selection for visual mimicry of host young by cuckoos, although this has not been demonstrated previously. Here we show that, in the eyes of hosts, nestlings of three bronze-cuckoo species are striking visual mimics of the young of their morphologically diverse hosts, providing the first evidence that coevolution can select for visual mimicry of hosts in cuckoo chicks. Bronze-cuckoos resemble their own hosts more closely than other host species, but the accuracy of mimicry varies according to the diversity of hosts they exploit. PMID:21227972


    ZHAO Ji-sheng; TAO Xia-xin; SHI Li-jing; OU Jin-ping


    Based on governing equations of saturated porous media and Liapunov's stability here, onset conditions matrix of porous media used by solid stress and Terzaghi's effective stress constitutive description under seepage flow state, are presented, which have different forms with different representation of the solid phase, matrix or skeleton, constitutive model of porous media. The main difference relates with how to describe the interaction between solid phase and liquid phase in constitutive model. The derived onset condition of strain localization under Terzaghi's effective stress description can be used to interpret different failure types, piping effect, landslides and mudflows, by means of the type and the magnitude ratio of relative movement between solid phase and liquid phase. Examples here illuminate the onset condition of how to work.

  7. Biosignatures of Pathogen and Host

    Fitch, J P; Chromy, B A; Forde, C E; Garcia, E; Gardner, S N; Gu, P P; Kuczmarksi, T A; Melius, C F; McCutchen-Maloney, S L; Milanovich, F P; Motin, V L; Ott, L L; Quong, A A; Quong, J N; Rocco, J M; Slezak, T R; Sokhansanj, B A; Vitalis, E A; Zemla, A T; McCready, P M


    In information theory, a signature is characterized by the information content as well as noise statistics of the communication channel. Biosignatures have analogous properties. A biosignature can be associated with a particular attribute of a pathogen or a host. However, the signature may be lost in backgrounds of similar or even identical signals from other sources. In this paper, we highlight statistical and signal processing challenges associated with identifying good biosignatures for pathogens in host and other environments. In some cases it may be possible to identify useful signatures of pathogens through indirect but amplified signals from the host. Discovery of these signatures requires new approaches to modeling and data interpretation. For environmental biosignal collections, it is possible to use signal processing techniques from other applications (e.g., synthetic aperture radar) to track the natural progression of microbes over large areas. We also present a computer-assisted approach to identify unique nucleic-acid based microbial signatures. Finally, an understanding of host-pathogen interactions will result in better detectors as well as opportunities in vaccines and therapeutics.

  8. Host Defence to Pulmonary Mycosis

    Christopher H Mody


    Full Text Available OBJECTIVE: To provide a basic understanding of the mechanisms of host defense to pathogenic fungi. This will help physicians understand why some patients are predisposed to fungal infections and update basic scientists on how microbial immunology applies to fungal disease.

  9. Host Event Based Network Monitoring

    Jonathan Chugg


    The purpose of INL’s research on this project is to demonstrate the feasibility of a host event based network monitoring tool and the effects on host performance. Current host based network monitoring tools work on polling which can miss activity if it occurs between polls. Instead of polling, a tool could be developed that makes use of event APIs in the operating system to receive asynchronous notifications of network activity. Analysis and logging of these events will allow the tool to construct the complete real-time and historical network configuration of the host while the tool is running. This research focused on three major operating systems commonly used by SCADA systems: Linux, WindowsXP, and Windows7. Windows 7 offers two paths that have minimal impact on the system and should be seriously considered. First is the new Windows Event Logging API, and, second, Windows 7 offers the ALE API within WFP. Any future work should focus on these methods.

  10. Understanding solid state physics

    Holgate, Sharon Ann


    Where Sharon Ann Holgate has succeeded in this book is in packing it with examples of the application of solid state physics to technology. … All the basic elements of solid state physics are covered … . The range of materials is good, including as it does polymers and glasses as well as crystalline solids. In general, the style makes for easy reading. … Overall this book succeeds in showing the relevance of solid state physics to the modern world … .-Contemporary Physics, Vol. 52, No. 2, 2011I was indeed amused and inspired by the wonderful images throughout the book, carefully selected by th

  11. Birefringence Oscillations In An Organic Guest-Host System

    Knabke, Gerhard; Franke, Hilmar; Frank, Werner F.


    The nonlinear dye N,N-Dihexyl-4 amino-4-nitrostilbene (DHANS) was incorporated in the polymer matrix of poly(α-methyl-styrene) (Pα MS). Dye concentrations between 1 and 10 weight % were investigated. Bulk samples of DHANS/Pα MS were prepared with a residual solvent content of 5 wt% in an optical cell between electrodes. Solid samples of high viscosity were obtained. Electrooptic measurements were perfomed for DC electric fields up to 30 RV/cm with a HeNe laser. Besides the usual Pockels- and Kerreffect we observed birefringence oscillations. For this experiment the Pα MS matrix has to be in the glass transition region. Parallel to the birefringence oscillations peaks in the DC current were measured. Frequency and amplitude of the oscillations depend on the external electric field. We suggest an interpretation of local discharging due to the anisotropic electrical conductivity of the dye molecules.

  12. Matrix product operators, matrix product states, and ab initio density matrix renormalization group algorithms

    Chan, Garnet Kin-Lic; Keselman, Anna; Nakatani, Naoki; Li, Zhendong; White, Steven R.


    Current descriptions of the ab initio density matrix renormalization group (DMRG) algorithm use two superficially different languages: an older language of the renormalization group and renormalized operators, and a more recent language of matrix product states and matrix product operators. The same algorithm can appear dramatically different when written in the two different vocabularies. In this work, we carefully describe the translation between the two languages in several contexts. First, we describe how to efficiently implement the ab initio DMRG sweep using a matrix product operator based code, and the equivalence to the original renormalized operator implementation. Next we describe how to implement the general matrix product operator/matrix product state algebra within a pure renormalized operator-based DMRG code. Finally, we discuss two improvements of the ab initio DMRG sweep algorithm motivated by matrix product operator language: Hamiltonian compression, and a sum over operators representation that allows for perfect computational parallelism. The connections and correspondences described here serve to link the future developments with the past and are important in the efficient implementation of continuing advances in ab initio DMRG and related algorithms.

  13. Matrix product operators, matrix product states, and ab initio density matrix renormalization group algorithms.

    Chan, Garnet Kin-Lic; Keselman, Anna; Nakatani, Naoki; Li, Zhendong; White, Steven R


    Current descriptions of the ab initio density matrix renormalization group (DMRG) algorithm use two superficially different languages: an older language of the renormalization group and renormalized operators, and a more recent language of matrix product states and matrix product operators. The same algorithm can appear dramatically different when written in the two different vocabularies. In this work, we carefully describe the translation between the two languages in several contexts. First, we describe how to efficiently implement the ab initio DMRG sweep using a matrix product operator based code, and the equivalence to the original renormalized operator implementation. Next we describe how to implement the general matrix product operator/matrix product state algebra within a pure renormalized operator-based DMRG code. Finally, we discuss two improvements of the ab initio DMRG sweep algorithm motivated by matrix product operator language: Hamiltonian compression, and a sum over operators representation that allows for perfect computational parallelism. The connections and correspondences described here serve to link the future developments with the past and are important in the efficient implementation of continuing advances in ab initio DMRG and related algorithms.

  14. GoM Diet Matrix

    National Oceanic and Atmospheric Administration, Department of Commerce — This data set was taken from CRD 08-18 at the NEFSC. Specifically, the Gulf of Maine diet matrix was developed for the EMAX exercise described in that center...

  15. Linear connections on matrix geometries

    Madore, J; Mourad, J; Madore, John; Masson, Thierry; Mourad, Jihad


    A general definition of a linear connection in noncommutative geometry has been recently proposed. Two examples are given of linear connections in noncommutative geometries which are based on matrix algebras. They both possess a unique metric connection.

  16. Matrix Quantum Mechanics from Qubits

    Hartnoll, Sean A; Mazenc, Edward A


    We introduce a transverse field Ising model with order N^2 spins interacting via a nonlocal quartic interaction. The model has an O(N,Z), hyperoctahedral, symmetry. We show that the large N partition function admits a saddle point in which the symmetry is enhanced to O(N). We further demonstrate that this `matrix saddle' correctly computes large N observables at weak and strong coupling. The matrix saddle undergoes a continuous quantum phase transition at intermediate couplings. At the transition the matrix eigenvalue distribution becomes disconnected. The critical excitations are described by large N matrix quantum mechanics. At the critical point, the low energy excitations are waves propagating in an emergent 1+1 dimensional spacetime.

  17. The R-matrix theory

    Descouvemont, P; Baye, D [Physique Nucleaire Theorique et Physique Mathematique, C.P. 229, Universite Libre de Bruxelles (ULB), B 1050 Brussels (Belgium)], E-mail:, E-mail:


    The different facets of the R-matrix method are presented pedagogically in a general framework. Two variants have been developed over the years: (i) The 'calculable' R-matrix method is a calculational tool to derive scattering properties from the Schroedinger equation in a large variety of physical problems. It was developed rather independently in atomic and nuclear physics with too little mutual influence. (ii) The 'phenomenological' R-matrix method is a technique to parametrize various types of cross sections. It was mainly (or uniquely) used in nuclear physics. Both directions are explained by starting from the simple problem of scattering by a potential. They are illustrated by simple examples in nuclear and atomic physics. In addition to elastic scattering, the R-matrix formalism is applied to inelastic and radiative-capture reactions. We also present more recent and more ambitious applications of the theory in nuclear physics.

  18. Detection of extracellular matrix modification in cancer models with inverse spectroscopic optical coherence tomography

    Spicer, Graham L. C.; Azarin, Samira M.; Yi, Ji; Young, Scott T.; Ellis, Ronald; Bauer, Greta M.; Shea, Lonnie D.; Backman, Vadim


    In cancer biology, there has been a recent effort to understand tumor formation in the context of the tissue microenvironment. In particular, recent progress has explored the mechanisms behind how changes in the cell-extracellular matrix ensemble influence progression of the disease. The extensive use of in vitro tissue culture models in simulant matrix has proven effective at studying such interactions, but modalities for non-invasively quantifying aspects of these systems are scant. We present the novel application of an imaging technique, Inverse Spectroscopic Optical Coherence Tomography, for the non-destructive measurement of in vitro biological samples during matrix remodeling. Our findings indicate that the nanoscale-sensitive mass density correlation shape factor D of cancer cells increases in response to a more crosslinked matrix. We present a facile technique for the non-invasive, quantitative study of the micro- and nano-scale structure of the extracellular matrix and its host cells.

  19. Manipulation of spontaneous emission dynamics of organic dyes in the porous silicon matrix.

    Makhal, Abhinandan; Kumar, Pushpendra; Lemmens, Peter; Pal, Samir Kumar


    The control of the spontaneous emission (SE) rate of dye molecules (4-dicyanomethylene-2-methyl-6-p-dimethylaminostyryl-4H-pyran (DCM) and Coumarin 523 (C523)) embedded in the Porous Silicon (PS) matrix has been studied using picosecond resolved fluorescence decay and polarization studies. We have shown that the SE rates of the two organic dyes embedded in the PS matrix depend on the relative positions of the emission maxima of the dyes with respect to electronic band gap energy of the PS matrix. We have also explored that the electronic band gap of the host PS matrix can easily be tuned by partial oxidation of the PS and the nature of SE of the embedded dyes can be tuned accordingly. The demonstrated retardation or enhancement of the spontaneous photon emission may enable the application of fluorescent organic molecules in PS matrix in several quantum optical devices including the realization of single photon sources.

  20. Improvement of the dissolution rate of silymarin by means of solid dispersions

    Li FQ; Hu JH


    Solid dispersions of silymarin were prepared by the fusion method with the intention of improving the dissolution properties of silymarin. Polyethylene glycol 6000 (PEG 6000) was used as the inert hydrophilic matrix. The dissolution studies of the solid dispersions were performed in vitro. And the results obtained showed that the dissolution rate of silymarin was considerably improved when formulated in solid dispersions with PEG 6000 as compared to original drug, and the increased dissolution rate might be favorable for further oral absorption.

  1. Solid dispersion application in pharmaceutical technology: Methods of preparation and characterization

    Medarević, Đorđe; Ibrić, Svetlana; Đuriš, Jelena; Đurić, Zorica


    A growing number of newly synthesized drugs exhibit low aqueous solubility, leading to poor bioavailability. Therefore, improving drug solubility and dissolution rate became one of the greatest challenges during formulation development. Solid dispersions formulation is one of the commonly investigated techniques for improving solubility of poorly soluble drugs. Solid dispersions are dispersions of one or more drugs in an inert carrier (matrix) in the solid state prepared by melting, solvent, ...

  2. Matrix analysis of electrical machinery

    Hancock, N N


    Matrix Analysis of Electrical Machinery, Second Edition is a 14-chapter edition that covers the systematic analysis of electrical machinery performance. This edition discusses the principles of various mathematical operations and their application to electrical machinery performance calculations. The introductory chapters deal with the matrix representation of algebraic equations and their application to static electrical networks. The following chapters describe the fundamentals of different transformers and rotating machines and present torque analysis in terms of the currents based on the p

  3. Location of Host and Host Habitat by Fruit Fly Parasitoids

    Pascal Rousse


    Full Text Available Augmentative releases of parasitoids may be a useful tool for the area-wide management of tephritid pests. The latter are parasitized by many wasp species, though only a few of them are relevant for augmentative biocontrol purposes. To date, nearly all the actual or potential biocontrol agents for such programs are egg or larval Opiinae parasitoids (Hymenoptera: Braconidae. Here, we review the literature published on their habitat and host location behavior, as well as the factors that modulate this behavior, which is assumed to be sequential; parasitoids forage first for the host habitat and then for the host itself. Parasitoids rely on chemical, visual, and mechanical stimuli, often strongly related to their ecology. Behavioral modulation factors include biotic and abiotic factors including learning, climatic conditions and physiological state of the insect. Finally, conclusions and perspectives for future research are briefly highlighted. A detailed knowledge of this behavior may be very useful for selecting the release sites for both inundative/augmentative releases of mass-reared parasitoids and inoculative releases for classical biocontrol.

  4. SVD row or column symmetric matrix


    A new architecture for row or column symmetric matrix called extended matrix is defined, and a precise correspondence of the singular values and singular vectors between the extended matrix and its original (namely, the mother matrix) is derived. As an illustration of potential, we show that, for a class of extended matrices, the singular value decomposition using the mother matrix rather than the extended matrix per se can save the CPU time and memory without loss of numerical precision.

  5. Matrix isolation sublimation: An apparatus for producing cryogenic beams of atoms and molecules

    Sacramento, R. L.; Oliveira, A. N.; Alves, B. X.; Silva, B. A.; Li, M. S.; Wolff, W.; Cesar, C. L.


    We describe the apparatus to generate cryogenic beams of atoms and molecules based on matrix isolation sublimation. Isolation matrices of Ne and H2 are hosts for atomic and molecular species which are sublimated into vacuum at cryogenic temperatures. The resulting cryogenic beams are used for high-resolution laser spectroscopy. The technique also aims at loading atomic and molecular traps.

  6. Cholesterol Biosensor Based on Entrapment of Monoenzyme and Multienzymes in Clay/Chitosan Hybrid Matrix

    Dan Shan; YanNa Wang; HuaiGuo Xue; En Han


    @@ This work aimed at showing the interest of the composite material based on layered double hydroxides(LDHs) and chitosan (CHT) as suitable host matrix likely to immobilize enzyme onto electrode surface for amperometric biosensing application.This hybrid material combined the advantages of inorganic LDHs and organic biopolymer,CHT.

  7. Matrix isolation sublimation: An apparatus for producing cryogenic beams of atoms and molecules

    Sacramento, R. L.; Alves, B. X.; Silva, B. A.; Wolff, W.; Cesar, C. L. [Instituto de Física, Universidade Federal do Rio de Janeiro, Caixa Postal 68528, 21941-972 Rio de Janeiro, RJ (Brazil); Oliveira, A. N. [Instituto de Física, Universidade Federal do Rio de Janeiro, Caixa Postal 68528, 21941-972 Rio de Janeiro, RJ (Brazil); INMETRO, Av. Nossa Senhora das Graças, 50 25250-020 Duque de Caxias, RJ (Brazil); Li, M. S. [Instituto de Física de São Carlos, Universidade de São Paulo, Ave. Trabalhador São Carlense, 400, 13565-590 São Carlos, SP (Brazil)


    We describe the apparatus to generate cryogenic beams of atoms and molecules based on matrix isolation sublimation. Isolation matrices of Ne and H{sub 2} are hosts for atomic and molecular species which are sublimated into vacuum at cryogenic temperatures. The resulting cryogenic beams are used for high-resolution laser spectroscopy. The technique also aims at loading atomic and molecular traps.

  8. Matrix isolation sublimation: An apparatus for producing cryogenic beams of atoms and molecules.

    Sacramento, R L; Oliveira, A N; Alves, B X; Silva, B A; Li, M S; Wolff, W; Cesar, C L


    We describe the apparatus to generate cryogenic beams of atoms and molecules based on matrix isolation sublimation. Isolation matrices of Ne and H2 are hosts for atomic and molecular species which are sublimated into vacuum at cryogenic temperatures. The resulting cryogenic beams are used for high-resolution laser spectroscopy. The technique also aims at loading atomic and molecular traps.

  9. Hardfacing of aluminium alloys by means of metal matrix composites produced by laser surface alloying

    Pityana, SL


    Full Text Available Metal matrix composite layers were formed on an aluminium substrate by means of laser surface alloying method. Aluminium 1200 was used as a host material and TiC particles were used as the reinforcement. The microstructure of the modified layer...

  10. Polyoma virus-induced osteosarcomas in inbred strains of mice: host determinants of metastasis.

    Palanivel Velupillai


    Full Text Available The mouse polyoma virus induces a broad array of solid tumors in mice of many inbred strains. In most strains tumors grow rapidly but fail to metastasize. An exception has been found in the Czech-II/Ei mouse in which bone tumors metastasize regularly to the lung. These tumors resemble human osteosarcoma in their propensity for pulmonary metastasis. Cell lines established from these metastatic tumors have been compared with ones from non-metastatic osteosarcomas arising in C3H/BiDa mice. Osteopontin, a chemokine implicated in migration and metastasis, is known to be transcriptionally induced by the viral middle T antigen. Czech-II/Ei and C3H/BiDa tumor cells expressed middle T and secreted osteopontin at comparable levels as the major chemoattractant. The tumor cell lines migrated equally well in response to recombinant osteopontin as the sole attractant. An important difference emerged in assays for invasion in which tumor cells from Czech-II/Ei mice were able to invade across an extracellular matrix barrier while those from C3H/BiDa mice were unable to invade. Invasive behavior was linked to elevated levels of the metalloproteinase MMP-2 and of the transcription factor NFAT. Inhibition of either MMP-2 or NFAT inhibited invasion by Czech-II/Ei osteosarcoma cells. The metastatic phenotype is dominant in F1 mice. Osteosarcoma cell lines from F1 mice expressed intermediate levels of MMP-2 and NFAT and were invasive. Osteosarcomas in Czech-II/Ei mice retain functional p53. This virus-host model of metastasis differs from engineered models targeting p53 or pRb and provides a system for investigating the genetic and molecular basis of bone tumor metastasis in the absence of p53 loss.

  11. Fibrinogen Is at the Interface of Host Defense and Pathogen Virulence in Staphylococcus aureus Infection

    Ko, Ya-Ping; Flick, Matthew J.


    Fibrinogen not only plays a pivotal role in hemostasis but also serves key roles in antimicrobial host defense. As a rapidly assembled provisional matrix protein, fibrin(ogen) can function as an early line of host protection by limiting bacterial growth, suppressing dissemination of microbes to distant sites, and mediating host bacterial killing. Fibrinogen-mediated host antimicrobial activity occurs predominantly through two general mechanisms, namely, fibrin matrices functioning as a protective barrier and fibrin(ogen) directly or indirectly driving host protective immune function. The potential of fibrin to limit bacterial infection and disease has been countered by numerous bacterial species evolving and maintaining virulence factors that engage hemostatic system components within vertebrate hosts. Bacterial factors have been isolated that simply bind fibrinogen or fibrin, promote fibrin polymer formation, or promote fibrin dissolution. Staphylococcus aureus is an opportunistic gram-positive bacterium, the causative agent of a wide range of human infectious diseases, and a prime example of a pathogen exquisitely sensitive to host fibrinogen. Indeed, current data suggest fibrinogen serves as a context-dependent determinant of host defense or pathogen virulence in Staphylococcus infection whose ultimate contribution is dictated by the expression of S. aureus virulence factors, the path of infection, and the tissue microenvironment. PMID:27056151

  12. Efficiency of Gas-Phase Ion Formation in Matrix-Assisted Laser Desorption Ionization with 2,5-Dihydroxybenzoic Acid as Matrix

    Park, Kyung Man; Ahn, Sung Hee; Bae, Yong Jin; Kim, Myung Soo [Seoul National Univ., Seoul (Korea, Republic of)


    Numbers of matrix- and analyte-derived ions and their sum in matrix-assisted laser desorption ionization (MALDI) of a peptide were measured using 2,5-dihydroxybenzoic acid (DHB) as matrix. As for MALDI with α-cyano-4-hydroxy cinnamic acid as matrix, the sum was independent of the peptide concentration in the solid sample, or was the same as that of pure DHB. This suggested that the matrix ion was the primary ion and that the peptide ion was generated by matrix-to-peptide proton transfer. Experimental ionization efficiencies of 10{sup -5}-10{sup -4} for peptides and 10{sup -8}-10{sup -7} for matrices are far smaller than 10.3-10.1 for peptides and 10{sup -5}-10{sup -3} for matrices speculated by Hillenkamp and Karas. Number of gas-phase ions generated by MALDI was unaffected by laser wavelength or pulse energy. This suggests that the main role of photo-absorption in MALDI is not in generating ions via a multi-photon process but in ablating materials in a solid sample to the gas phase.

  13. Minimal Realizations of Supersymmetry for Matrix Hamiltonians

    Andrianov, Alexandr A


    The notions of weak and strong minimizability of a matrix intertwining operator are introduced. Criterion of strong minimizability of a matrix intertwining operator is revealed. Criterion and sufficient condition of existence of a constant symmetry matrix for a matrix Hamiltonian are presented. A method of constructing of a matrix Hamiltonian with a given constant symmetry matrix in terms of a set of arbitrary scalar functions and eigen- and associated vectors of this matrix is offered. Examples of constructing of $2\\times2$ matrix Hamiltonians with given symmetry matrices for the cases of different structure of Jordan form of these matrices are elucidated.

  14. Applied mechanics of solids

    Bower, Allan F


    Modern computer simulations make stress analysis easy. As they continue to replace classical mathematical methods of analysis, these software programs require users to have a solid understanding of the fundamental principles on which they are based. Develop Intuitive Ability to Identify and Avoid Physically Meaningless Predictions Applied Mechanics of Solids is a powerful tool for understanding how to take advantage of these revolutionary computer advances in the field of solid mechanics. Beginning with a description of the physical and mathematical laws that govern deformation in solids, the text presents modern constitutive equations, as well as analytical and computational methods of stress analysis and fracture mechanics. It also addresses the nonlinear theory of deformable rods, membranes, plates, and shells, and solutions to important boundary and initial value problems in solid mechanics. The author uses the step-by-step manner of a blackboard lecture to explain problem solving methods, often providing...

  15. Sparse Planar Array Synthesis Using Matrix Enhancement and Matrix Pencil

    Mei-yan Zheng


    Full Text Available The matrix enhancement and matrix pencil (MEMP plays important roles in modern signal processing applications. In this paper, MEMP is applied to attack the problem of two-dimensional sparse array synthesis. Firstly, the desired array radiation pattern, as the original pattern for approximating, is sampled to form an enhanced matrix. After performing the singular value decomposition (SVD and discarding the insignificant singular values according to the prior approximate error, the minimum number of elements can be obtained. Secondly, in order to obtain the eigenvalues, the generalized eigen-decomposition is employed on the approximate matrix, which is the optimal low-rank approximation of the enhanced matrix corresponding to sparse planar array, and then the ESPRIT algorithm is utilized to pair the eigenvalues related to each dimension of the planar array. Finally, element positions and excitations of the sparse planar array are calculated according to the correct pairing of eigenvalues. Simulation results are presented to illustrate the effectiveness of the proposed approach.

  16. Solid-state single-photon emitters

    Aharonovich, Igor; Englund, Dirk; Toth, Milos


    Single-photon emitters play an important role in many leading quantum technologies. There is still no 'ideal' on-demand single-photon emitter, but a plethora of promising material systems have been developed, and several have transitioned from proof-of-concept to engineering efforts with steadily improving performance. Here, we review recent progress in the race towards true single-photon emitters required for a range of quantum information processing applications. We focus on solid-state systems including quantum dots, defects in solids, two-dimensional hosts and carbon nanotubes, as these are well positioned to benefit from recent breakthroughs in nanofabrication and materials growth techniques. We consider the main challenges and key advantages of each platform, with a focus on scalable on-chip integration and fabrication of identical sources on photonic circuits.

  17. Observations of Solids in Protoplanetary Disks

    Andrews, Sean M


    This review addresses the state of research that employs astronomical (remote sensing) observations of solids ("dust") in young circumstellar disks to learn about planet formation. The intention is for it to serve as an accessible, introductory, pedagogical resource for junior scientists interested in the subject. After some historical background and a basic observational primer, the focus is shifted to the three fundamental topics that broadly define the field: (1) demographics -- the relationships between disk properties and the characteristics of their environments and hosts; (2) structure -- the spatial distribution of disk material and its associated physical conditions and composition; and (3) evolution -- the signposts of key changes in disk properties, including the growth and migration of solids and the impact of dynamical interactions with young planetary systems. Based on the state of the art results in these areas, suggestions are made for potentially fruitful lines of work in the near future.

  18. Magnetic hyperthermia in solid magnetic colloids

    Zubarev, A. Yu.; Iskakova, L. Yu.; Abu-Bakr, A. F.


    We present results of theoretical study of magnetic hyperthermia in systems of single-domain ferromagnetic particles homogeneously distributed in a solid matrix. The heat effect is induced by linearly polarized alternating magnetic field. The effect of magnetic interaction between the particles as well as influence of orientation of the particles magnetic axes are in a focus of our consideration. Analysis shows that the interparticle interaction increases intensity of the heat production. The thermal effect in the systems with parallel orientation of the particles axes of easy magnetization is significantly higher than that in the case of random orientation of these axes.

  19. Host modulation by therapeutic agents

    Sugumari Elavarasu


    Full Text Available Periodontal disease susceptible group present advanced periodontal breakdown even though they achieve a high standard of oral hygiene. Various destructive enzymes and inflammatory mediators are involved in destruction. These are elevated in case of periodontal destruction. Host modulation aims at bringing these enzymes and mediators to normal level. Doxycycline, nonsteroidal anti-inflammatory drugs (NSAIDs, bisphosphonates, nitrous oxide (NO synthase inhibitors, recombinant human interleukin-11 (rhIL-11, omega-3 fatty acid, mouse anti-human interleukin-6 receptor antibody (MRA, mitogen-activated protein kinase (MAPK inhibitors, nuclear factor-kappa B (NF-kb inhibitors, osteoprotegerin, and tumor necrosis factor antagonist (TNF-α are some of the therapeutic agents that have host modulation properties.

  20. Extracellular Matrix-Based Biohybrid Materials for Engineering Compliant, Matrix-Dense Tissues.

    Bracaglia, Laura G; Fisher, John P


    An ideal tissue engineering scaffold should not only promote, but take an active role in, constructive remodeling and formation of site appropriate tissue. Extracellular matrix (ECM)-derived proteins provide unmatched cellular recognition, and therefore influence cellular response towards predicted remodeling behaviors. Materials built with only these proteins, however, can degrade rapidly or begin too weak to substitute for compliant, matrix-dense tissues. The focus of this Progress Report is on biohybrid materials that incorporate polymer components with ECM-derived proteins, to produce a substrate with desired mechanical and degradation properties, as well as actively guide tissue remodeling. Materials are described through four fabrication methods: 1) polymer and ECM-protein fibers woven together, 2) polymer and ECM proteins combined in a bilayer, 3) cell-built ECM on polymer scaffold, and 4) ECM proteins and polymers combined in a single hydrogel. Scaffolds from each fabrication method can achieve characteristics suitable for different types of tissue. In vivo testing has shown progressive remodeling in injury models, and suggests ECM-based biohybrid materials promote a prohealing immune response over single component alternatives. The prohealing immune response is associated with lasting success and long term host maintenance of the implant.



    To develop new kinds of matrix resin of composite and utilize lignosulfonate in large scale and high value, a kind of lignosulfonate was modified into epoxide in this paper. Two kinds of phenolized lignosulfonic acid and two kinds of lignin epoxides were prepared. The lignin epoxides and a kind of bisphenol-A epoxy resin were mixed respectively with a kind of liquid anhydride (MNA) to be measured by DSC technology. Both of these two kinds of epoxides can be cured by MNA, and curing exotherm of the liquid one is more than that of the solid one. Samples of the phenolized lignosulfonic acid and the epoxides were all analyzed by IR spectroscopy to find relations between them. It is suggested that the phenolation decide the type and the yield of the lignin epoxides.

  2. Source of slow lithium atoms from Ne or H2 matrix isolation sublimation

    Sacramento, R. L.; Alves, B. X.; Almeida, D. T.; Wolff, W.; Li, M. S.; Cesar, C. L.


    We have studied, via laser absorption spectroscopy, the velocity distribution of 7Li atoms released from cryogenic matrices of solid neon or molecular hydrogen. The Li atoms are implanted into the Ne or H2 matrices - grown onto a sapphire substrate - by laser ablation of a solid Li or LiH precursor. A heat pulse is then applied to the sapphire substrate sublimating the matrix together with the isolated atoms. With a NiCr film resistor deposited directly onto the sapphire substrate we are able to transfer high instantaneous power to the matrix, thus reaching a fast sublimation regime. In this regime the Li atoms can get entrained in the released matrix gas, and we were also able to achieve matrix sublimation times down to 10 μs for both H2 or Ne matrix, enabling us to proceed with the trapping of the species of our interest such as atomic hydrogen, lithium, and molecules. The sublimation of the H2 matrix, with its large center-of-mass velocity, provides evidence for a new regime of one-dimensional thermalization. The laser ablated Li seems to penetrate the H2 matrix deeper than it does in Ne.

  3. Source of slow lithium atoms from Ne or H2 matrix isolation sublimation.

    Sacramento, R L; Alves, B X; Almeida, D T; Wolff, W; Li, M S; Cesar, C L


    We have studied, via laser absorption spectroscopy, the velocity distribution of (7)Li atoms released from cryogenic matrices of solid neon or molecular hydrogen. The Li atoms are implanted into the Ne or H(2) matrices--grown onto a sapphire substrate--by laser ablation of a solid Li or LiH precursor. A heat pulse is then applied to the sapphire substrate sublimating the matrix together with the isolated atoms. With a NiCr film resistor deposited directly onto the sapphire substrate we are able to transfer high instantaneous power to the matrix, thus reaching a fast sublimation regime. In this regime the Li atoms can get entrained in the released matrix gas, and we were also able to achieve matrix sublimation times down to 10 μs for both H(2) or Ne matrix, enabling us to proceed with the trapping of the species of our interest such as atomic hydrogen, lithium, and molecules. The sublimation of the H(2) matrix, with its large center-of-mass velocity, provides evidence for a new regime of one-dimensional thermalization. The laser ablated Li seems to penetrate the H(2) matrix deeper than it does in Ne.

  4. Solid-to-solid oxidation of a vanadium(IV) to a vanadium(V) compound: chemisty of a sulfur-containing siderophore.

    Chatterjee, Pabitra B; Crans, Debbie C


    Visible light facilitates a solid-to-solid photochemical aerobic oxidation of a hunter-green microcrystalline oxidovanadium(IV) compound (1) to form a black powder of cis-dioxidovanadium(V) (2) at ambient temperature. The siderophore ligand pyridine-2,6-bis(thiocarboxylic acid), H(2)L, is secreted by a microorganism from the Pseudomonas genus. This irreversible transformation of a metal monooxo to a metal dioxo complex in the solid state in the absence of solvent is unprecedented. It serves as a proof-of-concept reaction for green chemistry occurring in solid matrixes.

  5. Do symbiotic bacteria subvert host immunity?

    Hooper, Lora V


    The mammalian intestine is home to dense and complex indigenous bacterial communities. Most of these bacteria establish beneficial symbiotic relationships with their hosts, making important contributions to host metabolism and digestive efficiency. The vast numbers of intestinal bacteria and their proximity to host tissues raise the question of how symbiotic host-bacterial relationships are established without eliciting potentially harmful immune responses. In light of the varied ways in which pathogenic bacteria manipulate host immunity, this Opinion article explores the role of immune suppression, subversion and evasion in the establishment of symbiotic host-bacterial associations.

  6. Hosting anions. The energetic perspective.

    Schmidtchen, Franz P


    Hosting anions addresses the widely spread molecular recognition event of negatively charged species by dedicated organic compounds in condensed phases at equilibrium. The experimentally accessible energetic features comprise the entire system including the solvent, any buffers, background electrolytes or other components introduced for e.g. analysis. The deconvolution of all these interaction types and their dependence on subtle structural variation is required to arrive at a structure-energy correlation that may serve as a guide in receptor construction. The focus on direct host-guest interactions (lock-and-key complementarity) that have dominated the binding concepts of artificial receptors in the past must be widened in order to account for entropic contributions which constitute very significant fractions of the total free energy of interaction. Including entropy necessarily addresses the ambiguity and fuzziness of the host-guest structural ensemble and requires the appreciation of the fact that most liquid phases possess distinct structures of their own. Apparently, it is the perturbation of the intrinsic solvent structure occurring upon association that rules ion binding in polar media where ions are soluble and abundant. Rather than specifying peculiar structural elements useful in anion binding this critical review attempts an illumination of the concepts and individual energetic contributions resulting in the final observation of specific anion recognition (95 references).

  7. Multiplexed Colorimetric Solid-Phase Extraction

    Gazda, Daniel B.; Fritz, James S.; Porter, Marc D.


    Multiplexed colorimetric solid-phase extraction (MC-SPE) is an extension of colorimetric solid-phase extraction (C-SPE) an analytical platform that combines colorimetric reagents, solid phase extraction, and diffuse reflectance spectroscopy to quantify trace analytes in water. In CSPE, analytes are extracted and complexed on the surface of an extraction membrane impregnated with a colorimetric reagent. The analytes are then quantified directly on the membrane surface using a handheld diffuse reflectance spectrophotometer. Importantly, the use of solid-phase extraction membranes as the matrix for impregnation of the colorimetric reagents creates a concentration factor that enables the detection of low concentrations of analytes in small sample volumes. In extending C-SPE to a multiplexed format, a filter holder that incorporates discrete analysis channels and a jig that facilitates the concurrent operation of multiple sample syringes have been designed, enabling the simultaneous determination of multiple analytes. Separate, single analyte membranes, placed in a readout cartridge create unique, analyte-specific addresses at the exit of each channel. Following sample exposure, the diffuse reflectance spectrum of each address is collected serially and the Kubelka-Munk function is used to quantify each water quality parameter via calibration curves. In a demonstration, MC-SPE was used to measure the pH of a sample and quantitate Ag(I) and Ni(II).

  8. Athermal nonlinear elastic constants of amorphous solids.

    Karmakar, Smarajit; Lerner, Edan; Procaccia, Itamar


    We derive expressions for the lowest nonlinear elastic constants of amorphous solids in athermal conditions (up to third order), in terms of the interaction potential between the constituent particles. The effect of these constants cannot be disregarded when amorphous solids undergo instabilities such as plastic flow or fracture in the athermal limit; in such situations the elastic response increases enormously, bringing the system much beyond the linear regime. We demonstrate that the existing theory of thermal nonlinear elastic constants converges to our expressions in the limit of zero temperature. We motivate the calculation by discussing two examples in which these nonlinear elastic constants play a crucial role in the context of elastoplasticity of amorphous solids. The first example is the plasticity-induced memory that is typical to amorphous solids (giving rise to the Bauschinger effect). The second example is how to predict the next plastic event from knowledge of the nonlinear elastic constants. Using the results of our calculations we derive a simple differential equation for the lowest eigenvalue of the Hessian matrix in the external strain near mechanical instabilities; this equation predicts how the eigenvalue vanishes at the mechanical instability and the value of the strain where the mechanical instability takes place.

  9. Organ-specific chemotactic factors present in lung extracellular matrix.

    Cerra, R F; Nathanson, S D


    The preferential colonization of a distant organ by a circulating tumor cell (organ specific metastasis) may be regulated by chemotactic factors present within the extracellular matrix of the host organ. Organ-specific extracellular matrix was prepared from murine kidney and lung by high salt extraction and DNAase/RNAase digestion. A soluble protein fraction (S2) from each of the matricies was obtained by 4 M guanidine extraction and was tested for organ-specific chemotactic activity in a modified Boyden chamber. The lung colonizing B16-F10 and B16-BL6 tumor cell lines demonstrated organ-specific motility only toward the lung extract. The low metastasizing B16 parental line and liver colonizing B16-L4b line showed no preference for either lung or kidney. The lung activity resolves into five fractions by gel filtration chromatography, with the highest activity eluting at Mr approximately 71,000. Chemotactic factors present in lung extracellular matrix may regulate the preferential colonization of an organ by stimulating the migration of tumor cells in a specific manner. These factors may be released during the degradation of the extracellular matrix.

  10. The Astrobiology Matrix and the "Drake Matrix" in Education

    Mizser, A.; Kereszturi, A.


    We organized astrobiology lectures in the Eotvos Lorand University of Sciences and the Polaris Observatory in 2002. We present here the "Drake matrix" for the comparison of the astrobiological potential of different bodies [1], and astrobiology matrix for the visualization of the interdisciplinary connections between different fields of astrobiology. Conclusion: In Hungary it is difficult to integrate astrobiology in the education system but the great advantage is that it can connect different scientific fields and improve the view of students. We would like to get in contact with persons and organizations who already have experience in the education of astrobiology.

  11. A survey of matrix theory and matrix inequalities

    Marcus, Marvin


    Written for advanced undergraduate students, this highly regarded book presents an enormous amount of information in a concise and accessible format. Beginning with the assumption that the reader has never seen a matrix before, the authors go on to provide a survey of a substantial part of the field, including many areas of modern research interest.Part One of the book covers not only the standard ideas of matrix theory, but ones, as the authors state, ""that reflect our own prejudices,"" among them Kronecker products, compound and induced matrices, quadratic relations, permanents, incidence

  12. Neodymium as a magnesium tetraborate matrix dopant and its applicability in dosimetry and as a temperature sensor

    Souza, Luiza F.; Antonio, Patrícia L.; Caldas, Linda V. E.; Souza, Divanizia N.


    MgB4O7 doped with lanthanides such as Dy3+ and Tm3+ are phosphors with very well established use in routine personal dosimetry. Certain characteristics, for example linearity in a broad dose range, low energy dependence, Zeff=8.5, high sensitivity and a relatively simple thermoluminescent (TL) emission curve make MgB4O7 a good material for thermoluminescent dosimetry. With the aim of analyzing other doping possibilities, this paper presents some preliminary results on the use of Nd3+ as a dopant in the MgB4O7 matrix. Furthermore, we evaluated the effect of using two different lanthanides, Nd and Dy, in the host matrix. In the present work, the phosphors were produced through solid state synthesis and X-ray diffraction confirmed the success of the technique. The TL behavior of MgB4O7:Nd was assessed when irradiated with gamma (60Co) and beta radiation, to determine the effect of the dopant concentration and the dose-response over a broad dose range. We also evaluated the dose-response of MgB4O7:Nd,Dy when irradiated with 60Co. The TL responses of the phosphors were compared with that of MgB4O7:Dy. These preliminary studies show that for the absorbed dose range studied, the sensitivity of MgB4O7:Nd,Dy was 3.8 and 28 times higher than that of MgB4O7:Dy and MgB4O7:Nd. The materials also presented linearity from 5 to 40 Gy. Above this value, the dose response curve exhibited sublinear behavior. These preliminary results will assist in developing a new temperature sensor based on a MgB4O7 dosimeter.

  13. Radionuclide solubility control by solid solutions

    Brandt, F.; Klinkenberg, M.; Rozov, K.; Bosbach, D. [Forschungszentrum Juelich GmbH (Germany). Inst. of Energy and Climate Research - Nuclear Waste Management and Reactor Safety (IEK-6); Vinograd, V. [Frankfurt Univ. (Germany). Inst. of Geosciences


    The migration of radionuclides in the geosphere is to a large extend controlled by sorption processes onto minerals and colloids. On a molecular level, sorption phenomena involve surface complexation, ion exchange as well as solid solution formation. The formation of solid solutions leads to the structural incorporation of radionuclides in a host structure. Such solid solutions are ubiquitous in natural systems - most minerals in nature are atomistic mixtures of elements rather than pure compounds because their formation leads to a thermodynamically more stable situation compared to the formation of pure compounds. However, due to a lack of reliable data for the expected scenario at close-to equilibrium conditions, solid solution systems have so far not been considered in long-term safety assessments for nuclear waste repositories. In recent years, various solid-solution aqueous solution systems have been studied. Here we present state-of-the art results regarding the formation of (Ra,Ba)SO{sub 4} solid solutions. In some scenarios describing a waste repository system for spent nuclear fuel in crystalline rocks {sup 226}Ra dominates the radiological impact to the environment associated with the potential release of radionuclides from the repository in the future. The solubility of Ra in equilibrium with (Ra,Ba)SO{sub 4} is much lower than the one calculated with RaSO{sub 4} as solubility limiting phase. Especially, the available literature data for the interaction parameter W{sub BaRa}, which describes the non-ideality of the solid solution, vary by about one order of magnitude (Zhu, 2004; Curti et al., 2010). The final {sup 226}Ra concentration in this system is extremely sensitive to the amount of barite, the difference in the solubility products of the end-member phases, and the degree of non-ideality of the solid solution phase. Here, we have enhanced the fundamental understanding regarding (1) the thermodynamics of (Ra,Ba)SO{sub 4} solid solutions and (2) the

  14. Matrix factorizations and elliptic fibrations

    Omer, Harun


    I use matrix factorizations to describe branes at simple singularities of elliptic fibrations. Each node of the corresponding Dynkin diagrams of the ADE-type singularities is associated with one indecomposable matrix factorization which can be deformed into one or more factorizations of lower rank. Branes with internal fluxes arise naturally as bound states of the indecomposable factorizations. Describing branes in such a way avoids the need to resolve singularities. This paper looks at gauge group breaking from E8 fibers down to SU (5) fibers due to the relevance of such fibrations for local F-theory GUT models. A purpose of this paper is to understand how the deformations of the singularity are understood in terms of its matrix factorizations. By systematically factorizing the elliptic fiber equation, this paper discusses geometries which are relevant for building semi-realistic local models. In the process it becomes evident that breaking patterns which are identical at the level of the Kodaira type of the fibers can be inequivalent at the level of matrix factorizations. Therefore the matrix factorization picture supplements information which the conventional less detailed descriptions lack.

  15. Octonionic matrix representation and electromagnetism

    Chanyal, B. C. [Kumaun University, S. S. J. Campus, Almora (India)


    Keeping in mind the important role of octonion algebra, we have obtained the electromagnetic field equations of dyons with an octonionic 8 x 8 matrix representation. In this paper, we consider the eight - dimensional octonionic space as a combination of two (external and internal) four-dimensional spaces for the existence of magnetic monopoles (dyons) in a higher-dimensional formalism. As such, we describe the octonion wave equations in terms of eight components from the 8 x 8 matrix representation. The octonion forms of the generalized potential, fields and current source of dyons in terms of 8 x 8 matrix are discussed in a consistent manner. Thus, we have obtained the generalized Dirac-Maxwell equations of dyons from an 8x8 matrix representation of the octonion wave equations in a compact and consistent manner. The generalized Dirac-Maxwell equations are fully symmetric Maxwell equations and allow for the possibility of magnetic charges and currents, analogous to electric charges and currents. Accordingly, we have obtained the octonionic Dirac wave equations in an external field from the matrix representation of the octonion-valued potentials of dyons.

  16. Matrix factorizations and elliptic fibrations

    Harun Omer


    Full Text Available I use matrix factorizations to describe branes at simple singularities of elliptic fibrations. Each node of the corresponding Dynkin diagrams of the ADE-type singularities is associated with one indecomposable matrix factorization which can be deformed into one or more factorizations of lower rank. Branes with internal fluxes arise naturally as bound states of the indecomposable factorizations. Describing branes in such a way avoids the need to resolve singularities. This paper looks at gauge group breaking from E8 fibers down to SU(5 fibers due to the relevance of such fibrations for local F-theory GUT models. A purpose of this paper is to understand how the deformations of the singularity are understood in terms of its matrix factorizations. By systematically factorizing the elliptic fiber equation, this paper discusses geometries which are relevant for building semi-realistic local models. In the process it becomes evident that breaking patterns which are identical at the level of the Kodaira type of the fibers can be inequivalent at the level of matrix factorizations. Therefore the matrix factorization picture supplements information which the conventional less detailed descriptions lack.

  17. Novel lanthanide doped micro- and mesoporous solids. Characterization of ion-host-interactions, species distribution and luminescence properties using time-resolved luminescence spectroscopy; Neuartige Lanthanoid-dotierte mikro- und mesoporoese Feststoffe. Charakterisierung von Ion-Wirt-Wechselwirkungen, Speziesverteilung und Lumineszenzeigenschaften mittels zeitaufgeloester Lumineszenzspektroskopie

    Gessner, Andre


    In this work lanthanide-doped microporous zeolites, microporous-mesoporous hybrid materials and mesoporous silicates were investigated regarding their luminescence properties and the ion-host-interactions using time-resolved luminescence spectroscopy. Thereby, time-resolved emission spectra (TRES) provide information in the wavelength and time domain. For the analysis of the TRES a broad set of analytic methods was applied and thus a corresponding ''toolbox'' developed. Fitting of the luminescence decays was performed with a discrete number of exponentials and supported by luminescence decay times distributions. Time-resolved area normalized emission spectra (TRANES), an advancement of TRES, could be used for the determination of the number of emissive lanthanide species in porous materials for the first time. Calculation of the decay-associated spectra (DAS) allowed the correlation of spectral information with luminescence decay times and thus delivered the luminescence spectra of the different europium species. For europium(III) we could use in addition the time-dependent asymmetry ratio and spectral evolution of the {sup 5}D{sub 0}-{sup 7}F{sub 0}-transition with time to obtain further information about the distribution of the lanthanide ions in the host material. Luminescence decay times and spectra allowed conclusions on the number of OH-oscillators in and the symmetry of the first coordination sphere. For the microporous and microporous-mesoporous materials were found different lanthanide species, which were characterized by the above mentioned methods. These lanthanide species can be found on different positions in the host material. One position is located deep in the pore system. Here, lanthanide ions are hardly accessible for water and mainly coordinated by framework oxygens. This results in long luminescence decay times and distorted coordination spheres. The second position can be found near or on the outer surface or in the

  18. Solidification phenomena in metal matrix nanocomposites

    de Cicco, Michael Peter


    Nanoparticles in metal matrix nanocomposites (MMNCs) were shown to act as catalysts for nucleation of solidification of the matrix alloy, as well as to alter the intermetallic phase formation. These phenomena were studied in zinc, aluminum, and magnesium alloys. In all alloys studied, a refinement of the microstructure was seen with the addition of the nanoparticles. Various types of nanoparticles were used and had varying degrees of refinement. In a zinc alloy, AC43A, SiC, TiC, and Al2O3 gamma nanoparticles were all found to refine the alloy. Thermal analysis of bulk samples showed the onset of solidification at reduced undercoolings, indicating nucleation catalysis. Nucleation of the primary phase was also observed by employing the droplet emulsion technique (DET). DET results showed that the secondary phase nucleation was also catalyzed by the nanoparticles. Exploiting the nucleation catalysis of the nanoparticles and the associated grain refinement, a semi-solid casting (SSC) process was demonstrated in AC43A + SiC nanocomposites. This novel process successfully incorporated the strength enhancement of MMNCs and the casting quality benefits of SSC. This process required no additional processing steps or material handling typical of existing SSC processes. The nucleation catalysis of the nanoparticles was sufficient to create semi-solid slurries appropriate for SSC. Nanoparticle induced nucleation catalysis was also examined in a common aluminum alloy, A356, using the DET. All nanoparticles catalyzed nucleation of the primary Al phase. However, undercoolings varied depending on the nanoparticle identity and average diameter. The variation in undercoolings generally agreed with a modified lattice disregistry theory and the free growth theory. For nanoparticles with a small lattice spacing mismatch with the Al phase, undercoolings approached the size dependent free growth limit. Binary alloys of magnesium and zinc showed significant strength and ductility

  19. Host compatibility rather than vector-host-encounter rate determines the host range of avian Plasmodium parasites.

    Medeiros, Matthew C I; Hamer, Gabriel L; Ricklefs, Robert E


    Blood-feeding arthropod vectors are responsible for transmitting many parasites between vertebrate hosts. While arthropod vectors often feed on limited subsets of potential host species, little is known about the extent to which this influences the distribution of vector-borne parasites in some systems. Here, we test the hypothesis that different vector species structure parasite-host relationships by restricting access of certain parasites to a subset of available hosts. Specifically, we investigate how the feeding patterns of Culex mosquito vectors relate to distributions of avian malaria parasites among hosts in suburban Chicago, IL, USA. We show that Plasmodium lineages, defined by cytochrome b haplotypes, are heterogeneously distributed across avian hosts. However, the feeding patterns of the dominant vectors (Culex restuans and Culex pipiens) are similar across these hosts, and do not explain the distributions of Plasmodium parasites. Phylogenetic similarity of avian hosts predicts similarity in their Plasmodium parasites. This effect was driven primarily by the general association of Plasmodium parasites with particular host superfamilies. Our results suggest that a mosquito-imposed encounter rate does not limit the distribution of avian Plasmodium parasites across hosts. This implies that compatibility between parasites and their avian hosts structure Plasmodium host range.

  20. Value of established solid-organ transplant tolerance from experience of host im-munomodulation with helminth infection%蠕虫感染的免疫调节作用在诱导器官移植免疫耐受中应用价值的探讨

    明英姿; 邹义洲


    器官移植是重建器官功能的有效治疗方法,探寻无需长期服用免疫抑制的移植免疫耐受则是当前研究的热点。尽管几种诱导器官移植免疫耐受的方案已经被提出,甚至有些已应用于临床Ⅰ期试验,但这些免疫耐受诱导方案并没有达到理想的效果。本文从蠕虫感染能够长期调节宿主免疫反应的能力出发,从理论上阐明将蠕虫抗原用作调节受者免疫耐受的诱导的理论依据,提出受者免疫系统对供者移植器官的免疫耐受的形成需要供体抗原的刺激。输注供者脾脏来源的B淋巴细胞在联合蠕虫可溶性抗原作用下,让受者诱导供者特异性的免疫耐受具有重要的研究价值。%Organ transplantation is the effective method to replace the function of the patient failed organ. But it is very disappoint that recipients have to receive the long-term immunosuppression regimens for prevention of allograft rejection. To induce allograft immune tolerance without immunosuppressant is in great demand. Although several tolerance strategies for organ transplant have been proposed, even some has already been tested in the 1st clinical trial, these strategies haven ' t approached to ideal efficacy. Helminths are remarkably successful parasites to achieve immunological tolerance to host immune response. It is now well established that the parasites′ success is the result of active immunomodulation of their hosts ' immune response. We suggest that injecting B cells from donor spleen and helminth soluble antigens, recipient might become tolerance to donor organ, but not tolerated to other antigens. Research based on this approach has great translated value for future clinic practice.